/src/libarchive/libarchive/archive_read_support_format_tar.c

Source
/*-
 * Copyright (c) 2003-2023 Tim Kientzle
 * Copyright (c) 2011-2012 Michihiro NAKAJIMA
 * Copyright (c) 2016 Martin Matuska
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR(S) BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "archive_platform.h"

#ifdef HAVE_ERRNO_H
#include <errno.h>
#endif
#include <stddef.h>
#ifdef HAVE_STDLIB_H
#include <stdlib.h>
#endif
#ifdef HAVE_STRING_H
#include <string.h>
#endif

#include "archive.h"
#include "archive_acl_private.h" /* For ACL parsing routines. */
#include "archive_entry.h"
#include "archive_entry_locale.h"
#include "archive_private.h"
#include "archive_read_private.h"

#define tar_min(a,b) ((a) < (b) ? (a) : (b))

/*
 * Layout of POSIX 'ustar' tar header.
 */
struct archive_entry_header_ustar {
  char  name[100];
  char  mode[8];
  char  uid[8];
  char  gid[8];
  char  size[12];
  char  mtime[12];
  char  checksum[8];
  char  typeflag[1];
  char  linkname[100];  /* "old format" header ends here */
  char  magic[6]; /* For POSIX: "ustar\0" */
  char  version[2]; /* For POSIX: "00" */
  char  uname[32];
  char  gname[32];
  char  rdevmajor[8];
  char  rdevminor[8];
  char  prefix[155];
};

/*
 * Structure of GNU tar header
 */
struct gnu_sparse {
  char  offset[12];
  char  numbytes[12];
};

struct archive_entry_header_gnutar {
  char  name[100];
  char  mode[8];
  char  uid[8];
  char  gid[8];
  char  size[12];
  char  mtime[12];
  char  checksum[8];
  char  typeflag[1];
  char  linkname[100];
  char  magic[8];  /* "ustar  \0" (note blank/blank/null at end) */
  char  uname[32];
  char  gname[32];
  char  rdevmajor[8];
  char  rdevminor[8];
  char  atime[12];
  char  ctime[12];
  char  offset[12];
  char  longnames[4];
  char  unused[1];
  struct gnu_sparse sparse[4];
  char  isextended[1];
  char  realsize[12];
  /*
   * Old GNU format doesn't use POSIX 'prefix' field; they use
   * the 'L' (longname) entry instead.
   */
};

/*
 * Data specific to this format.
 */
struct sparse_block {
  struct sparse_block *next;
  int64_t offset;
  int64_t remaining;
  int hole;
};

struct tar {
  struct archive_string  entry_pathname;
  /* For "GNU.sparse.name" and other similar path extensions. */
  struct archive_string  entry_pathname_override;
  struct archive_string  entry_uname;
  struct archive_string  entry_gname;
  struct archive_string  entry_linkpath;
  struct archive_string  line;
  int      pax_hdrcharset_utf8;
  int64_t      entry_bytes_remaining;
  int64_t      entry_offset;
  int64_t      entry_padding;
  int64_t      entry_bytes_unconsumed;
  int64_t      disk_size;
  int64_t      GNU_sparse_realsize;
  int64_t      GNU_sparse_size;
  int64_t      SCHILY_sparse_realsize;
  int64_t      pax_size;
  struct sparse_block *sparse_list;
  struct sparse_block *sparse_last;
  int64_t      sparse_offset;
  int64_t      sparse_numbytes;
  int      sparse_gnu_major;
  int      sparse_gnu_minor;
  char       sparse_gnu_attributes_seen;
  char       filetype;
  char       size_fields; /* Bits defined below */

  struct archive_string  localname;
  struct archive_string_conv *opt_sconv;
  struct archive_string_conv *sconv;
  struct archive_string_conv *sconv_acl;
  struct archive_string_conv *sconv_default;
  int      init_default_conversion;
  int      compat_2x;
  int      process_mac_extensions;
  int      read_concatenated_archives;
  int      default_inode;
  int      default_dev;
};

/* Track which size fields were present in the headers */
#define TAR_SIZE_PAX_SIZE 1
#define TAR_SIZE_GNU_SPARSE_REALSIZE 2
#define TAR_SIZE_GNU_SPARSE_SIZE 4
#define TAR_SIZE_SCHILY_SPARSE_REALSIZE 8


static int  archive_block_is_null(const char *p);
static char *base64_decode(const char *, size_t, size_t *);
static int  gnu_add_sparse_entry(struct archive_read *, struct tar *,
        int64_t offset, int64_t remaining);

static void gnu_clear_sparse_list(struct tar *);
static int  gnu_sparse_old_read(struct archive_read *, struct tar *,
        const struct archive_entry_header_gnutar *header, int64_t *);
static int  gnu_sparse_old_parse(struct archive_read *, struct tar *,
        const struct gnu_sparse *sparse, int length);
static int  gnu_sparse_01_parse(struct archive_read *, struct tar *,
        const char *, size_t);
static int64_t  gnu_sparse_10_read(struct archive_read *, struct tar *,
        int64_t *);
static int  header_Solaris_ACL(struct archive_read *,  struct tar *,
        struct archive_entry *, const void *, int64_t *);
static int  header_common(struct archive_read *,  struct tar *,
        struct archive_entry *, const void *);
static int  header_old_tar(struct archive_read *, struct tar *,
        struct archive_entry *, const void *);
static int  header_pax_extension(struct archive_read *, struct tar *,
        struct archive_entry *, const void *, int64_t *);
static int  header_pax_global(struct archive_read *, struct tar *,
        struct archive_entry *, const void *h, int64_t *);
static int  header_gnu_longlink(struct archive_read *, struct tar *,
        struct archive_entry *, const void *h, int64_t *);
static int  header_gnu_longname(struct archive_read *, struct tar *,
        struct archive_entry *, const void *h, int64_t *);
static int  is_mac_metadata_entry(struct archive_entry *entry);
static int  read_mac_metadata_blob(struct archive_read *,
        struct archive_entry *, int64_t *);
static int  header_volume(struct archive_read *, struct tar *,
        struct archive_entry *, const void *h, int64_t *);
static int  header_ustar(struct archive_read *, struct tar *,
        struct archive_entry *, const void *h);
static int  header_gnutar(struct archive_read *, struct tar *,
        struct archive_entry *, const void *h, int64_t *);
static int  archive_read_format_tar_bid(struct archive_read *, int);
static int  archive_read_format_tar_options(struct archive_read *,
        const char *, const char *);
static int  archive_read_format_tar_cleanup(struct archive_read *);
static int  archive_read_format_tar_read_data(struct archive_read *a,
        const void **buff, size_t *size, int64_t *offset);
static int  archive_read_format_tar_skip(struct archive_read *a);
static int  archive_read_format_tar_read_header(struct archive_read *,
        struct archive_entry *);
static int  checksum(struct archive_read *, const void *);
static int  pax_attribute(struct archive_read *, struct tar *,
        struct archive_entry *, const char *key, size_t key_length,
        size_t value_length, int64_t *unconsumed);
static int  pax_attribute_LIBARCHIVE_xattr(struct archive_entry *,
        const char *, size_t, const char *, size_t);
static int  pax_attribute_SCHILY_acl(struct archive_read *, struct tar *,
        struct archive_entry *, size_t, int);
static int  pax_attribute_SUN_holesdata(struct archive_read *, struct tar *,
        struct archive_entry *, const char *, size_t);
static void pax_time(const char *, size_t, int64_t *sec, long *nanos);
static ssize_t  readline(struct archive_read *, struct tar *, const char **,
        ssize_t limit, int64_t *);
static int  read_body_to_string(struct archive_read *, struct tar *,
        struct archive_string *, const void *h, int64_t *);
static int  read_bytes_to_string(struct archive_read *,
        struct archive_string *, size_t, int64_t *);
static int64_t  tar_atol(const char *, size_t);
static int64_t  tar_atol10(const char *, size_t);
static int64_t  tar_atol256(const char *, size_t);
static int64_t  tar_atol8(const char *, size_t);
static int  tar_read_header(struct archive_read *, struct tar *,
        struct archive_entry *, int64_t *);
static int  tohex(int c);
static char *url_decode(const char *, size_t);
static int  tar_flush_unconsumed(struct archive_read *, int64_t *);

/* Sanity limits:  These numbers should be low enough to
 * prevent a maliciously-crafted archive from forcing us to
 * allocate extreme amounts of memory.  But of course, they
 * need to be high enough for any correct value.  These
 * will likely need some adjustment as we get more experience. */
static const size_t guname_limit = 65536; /* Longest uname or gname: 64kiB */
static const size_t pathname_limit = 1048576; /* Longest path name: 1MiB */
static const size_t sparse_map_limit = 8 * 1048576; /* Longest sparse map: 8MiB */
static const size_t xattr_limit = 16 * 1048576; /* Longest xattr: 16MiB */
static const size_t fflags_limit = 512; /* Longest fflags */
static const size_t acl_limit = 131072; /* Longest textual ACL: 128kiB */
static const int64_t entry_limit = 0xfffffffffffffffLL; /* 2^60 bytes = 1 ExbiByte */

/*
 * There's no standard for TIME_T_MAX.  So we compute it
 * here.  TODO: Move this to configure time, but be careful
 * about cross-compile environments.
 */
static time_t
get_time_t_max(void)
{
#if defined(TIME_T_MAX)
        return TIME_T_MAX;
#else
        /* ISO C allows time_t to be a floating-point type,
           but POSIX requires an integer type.  The following
           should work on any system that follows the POSIX
           conventions. */
        if (((time_t)0) < ((time_t)-1)) {
                /* Time_t is unsigned */
                return (~(time_t)0);
        } else {
                /* Time_t is signed. */
                /* Assume it's the same as int64_t or int32_t */
                if (sizeof(time_t) == sizeof(int64_t)) {
                        return (time_t)INT64_MAX;
                } else {
                        return (time_t)INT32_MAX;
                }
        }
#endif
}

int
archive_read_support_format_gnutar(struct archive *a)
{
  archive_check_magic(a, ARCHIVE_READ_MAGIC,
      ARCHIVE_STATE_NEW, "archive_read_support_format_gnutar");
  return (archive_read_support_format_tar(a));
}


int
archive_read_support_format_tar(struct archive *_a)
{
  struct archive_read *a = (struct archive_read *)_a;
  struct tar *tar;
  int r;

  archive_check_magic(_a, ARCHIVE_READ_MAGIC,
      ARCHIVE_STATE_NEW, "archive_read_support_format_tar");

  tar = calloc(1, sizeof(*tar));
  if (tar == NULL) {
    archive_set_error(&a->archive, ENOMEM,
        "Can't allocate tar data");
    return (ARCHIVE_FATAL);
  }
#ifdef HAVE_COPYFILE_H
  /* Set this by default on Mac OS. */
  tar->process_mac_extensions = 1;
#endif

  r = __archive_read_register_format(a, tar, "tar",
      archive_read_format_tar_bid,
      archive_read_format_tar_options,
      archive_read_format_tar_read_header,
      archive_read_format_tar_read_data,
      archive_read_format_tar_skip,
      NULL,
      archive_read_format_tar_cleanup,
      NULL,
      NULL);

  if (r != ARCHIVE_OK)
    free(tar);
  return (ARCHIVE_OK);
}

static int
archive_read_format_tar_cleanup(struct archive_read *a)
{
  struct tar *tar;

  tar = (struct tar *)(a->format->data);
  gnu_clear_sparse_list(tar);
  archive_string_free(&tar->entry_pathname);
  archive_string_free(&tar->entry_pathname_override);
  archive_string_free(&tar->entry_uname);
  archive_string_free(&tar->entry_gname);
  archive_string_free(&tar->entry_linkpath);
  archive_string_free(&tar->line);
  archive_string_free(&tar->localname);
  free(tar);
  (a->format->data) = NULL;
  return (ARCHIVE_OK);
}

/*
 * Validate number field
 *
 * This has to be pretty lenient in order to accommodate the enormous
 * variety of tar writers in the world:
 *  = POSIX (IEEE Std 1003.1-1988) ustar requires octal values with leading
 *    zeros and allows fields to be terminated with space or null characters
 *  = Many writers use different termination (in particular, libarchive
 *    omits terminator bytes to squeeze one or two more digits)
 *  = Many writers pad with space and omit leading zeros
 *  = GNU tar and star write base-256 values if numbers are too
 *    big to be represented in octal
 *
 *  Examples of specific tar headers that we should support:
 *  = Perl Archive::Tar terminates uid, gid, devminor and devmajor with two
 *    null bytes, pads size with spaces and other numeric fields with zeroes
 *  = plexus-archiver prior to 2.6.3 (before switching to commons-compress)
 *    may have uid and gid fields filled with spaces without any octal digits
 *    at all and pads all numeric fields with spaces
 *
 * This should tolerate all variants in use.  It will reject a field
 * where the writer just left garbage after a trailing NUL.
 */
static int
validate_number_field(const char* p_field, size_t i_size)
{
  unsigned char marker = (unsigned char)p_field[0];
  if (marker == 128 || marker == 255 || marker == 0) {
    /* Base-256 marker, there's nothing we can check. */
    return 1;
  } else {
    /* Must be octal */
    size_t i = 0;
    /* Skip any leading spaces */
    while (i < i_size && p_field[i] == ' ') {
      ++i;
    }
    /* Skip octal digits. */
    while (i < i_size && p_field[i] >= '0' && p_field[i] <= '7') {
      ++i;
    }
    /* Any remaining characters must be space or NUL padding. */
    while (i < i_size) {
      if (p_field[i] != ' ' && p_field[i] != 0) {
        return 0;
      }
      ++i;
    }
    return 1;
  }
}

static int
archive_read_format_tar_bid(struct archive_read *a, int best_bid)
{
  int bid;
  const char *h;
  const struct archive_entry_header_ustar *header;

  (void)best_bid; /* UNUSED */

  bid = 0;

  /* Now let's look at the actual header and see if it matches. */
  h = __archive_read_ahead(a, 512, NULL);
  if (h == NULL)
    return (-1);

  /* If it's an end-of-archive mark, we can handle it. */
  if (h[0] == 0 && archive_block_is_null(h)) {
    /*
     * Usually, I bid the number of bits verified, but
     * in this case, 4096 seems excessive so I picked 10 as
     * an arbitrary but reasonable-seeming value.
     */
    return (10);
  }

  /* If it's not an end-of-archive mark, it must have a valid checksum.*/
  if (!checksum(a, h))
    return (0);
  bid += 48;  /* Checksum is usually 6 octal digits. */

  header = (const struct archive_entry_header_ustar *)h;

  /* Recognize POSIX formats. */
  if ((memcmp(header->magic, "ustar\0", 6) == 0)
      && (memcmp(header->version, "00", 2) == 0))
    bid += 56;

  /* Recognize GNU tar format. */
  if ((memcmp(header->magic, "ustar ", 6) == 0)
      && (memcmp(header->version, " \0", 2) == 0))
    bid += 56;

  /* Type flag must be null, digit or A-Z, a-z. */
  if (header->typeflag[0] != 0 &&
      !( header->typeflag[0] >= '0' && header->typeflag[0] <= '9') &&
      !( header->typeflag[0] >= 'A' && header->typeflag[0] <= 'Z') &&
      !( header->typeflag[0] >= 'a' && header->typeflag[0] <= 'z') )
    return (0);
  bid += 2;  /* 6 bits of variation in an 8-bit field leaves 2 bits. */

  /*
   * Check format of mode/uid/gid/mtime/size/rdevmajor/rdevminor fields.
   */
  if (validate_number_field(header->mode, sizeof(header->mode)) == 0
      || validate_number_field(header->uid, sizeof(header->uid)) == 0
      || validate_number_field(header->gid, sizeof(header->gid)) == 0
      || validate_number_field(header->mtime, sizeof(header->mtime)) == 0
      || validate_number_field(header->size, sizeof(header->size)) == 0
      || validate_number_field(header->rdevmajor, sizeof(header->rdevmajor)) == 0
      || validate_number_field(header->rdevminor, sizeof(header->rdevminor)) == 0) {
    bid = 0;
  }

  return (bid);
}

static int
archive_read_format_tar_options(struct archive_read *a,
    const char *key, const char *val)
{
  struct tar *tar;
  int ret = ARCHIVE_FAILED;

  tar = (struct tar *)(a->format->data);
  if (strcmp(key, "compat-2x")  == 0) {
    /* Handle UTF-8 filenames as libarchive 2.x */
    tar->compat_2x = (val != NULL && val[0] != 0);
    tar->init_default_conversion = tar->compat_2x;
    return (ARCHIVE_OK);
  } else if (strcmp(key, "hdrcharset")  == 0) {
    if (val == NULL || val[0] == 0)
      archive_set_error(&a->archive, ARCHIVE_ERRNO_MISC,
          "tar: hdrcharset option needs a character-set name");
    else {
      tar->opt_sconv =
          archive_string_conversion_from_charset(
        &a->archive, val, 0);
      if (tar->opt_sconv != NULL)
        ret = ARCHIVE_OK;
      else
        ret = ARCHIVE_FATAL;
    }
    return (ret);
  } else if (strcmp(key, "mac-ext") == 0) {
    tar->process_mac_extensions = (val != NULL && val[0] != 0);
    return (ARCHIVE_OK);
  } else if (strcmp(key, "read_concatenated_archives") == 0) {
    tar->read_concatenated_archives = (val != NULL && val[0] != 0);
    return (ARCHIVE_OK);
  }

  /* Note: The "warn" return is just to inform the options
   * supervisor that we didn't handle it.  It will generate
   * a suitable error if no one used this option. */
  return (ARCHIVE_WARN);
}

/* utility function- this exists to centralize the logic of tracking
 * how much unconsumed data we have floating around, and to consume
 * anything outstanding since we're going to do read_aheads
 */
static int
tar_flush_unconsumed(struct archive_read *a, int64_t *unconsumed)
{
  if (*unconsumed) {
/*
    void *data = (void *)__archive_read_ahead(a, *unconsumed, NULL);
     * this block of code is to poison claimed unconsumed space, ensuring
     * things break if it is in use still.
     * currently it WILL break things, so enable it only for debugging this issue
    if (data) {
      memset(data, 0xff, *unconsumed);
    }
*/
    int64_t consumed = __archive_read_consume(a, *unconsumed);
    if (consumed != *unconsumed) {
      return (ARCHIVE_FATAL);
    }
    *unconsumed = 0;
  }
  return (ARCHIVE_OK);
}

/*
 * The function invoked by archive_read_next_header().  This
 * just sets up a few things and then calls the internal
 * tar_read_header() function below.
 */
static int
archive_read_format_tar_read_header(struct archive_read *a,
    struct archive_entry *entry)
{
  /*
   * When converting tar archives to cpio archives, it is
   * essential that each distinct file have a distinct inode
   * number.  To simplify this, we keep a static count here to
   * assign fake dev/inode numbers to each tar entry.  Note that
   * pax format archives may overwrite this with something more
   * useful.
   *
   * Ideally, we would track every file read from the archive so
   * that we could assign the same dev/ino pair to hardlinks,
   * but the memory required to store a complete lookup table is
   * probably not worthwhile just to support the relatively
   * obscure tar->cpio conversion case.
   */
  struct tar *tar;
  const char *p;
  const wchar_t *wp;
  int r;
  size_t l;
  int64_t unconsumed = 0;

  tar = (struct tar *)(a->format->data);

  /* Assign default device/inode values. */
  archive_entry_set_dev(entry, 1 + tar->default_dev); /* Don't use zero. */
  archive_entry_set_ino(entry, ++tar->default_inode); /* Don't use zero. */
  /* Limit generated st_ino number to 16 bits. */
  if (tar->default_inode >= 0xffff) {
    ++tar->default_dev;
    tar->default_inode = 0;
  }

  tar->entry_offset = 0;
  gnu_clear_sparse_list(tar);
  tar->size_fields = 0; /* We don't have any size info yet */

  /* Setup default string conversion. */
  tar->sconv = tar->opt_sconv;
  if (tar->sconv == NULL) {
    if (!tar->init_default_conversion) {
      tar->sconv_default =
          archive_string_default_conversion_for_read(&(a->archive));
      tar->init_default_conversion = 1;
    }
    tar->sconv = tar->sconv_default;
  }

  r = tar_read_header(a, tar, entry, &unconsumed);

  tar_flush_unconsumed(a, &unconsumed);

  /*
   * "non-sparse" files are really just sparse files with
   * a single block.
   */
  if (tar->sparse_list == NULL) {
    if (gnu_add_sparse_entry(a, tar, 0, tar->entry_bytes_remaining)
        != ARCHIVE_OK)
      return (ARCHIVE_FATAL);
  } else {
    struct sparse_block *sb;

    for (sb = tar->sparse_list; sb != NULL; sb = sb->next) {
      if (!sb->hole)
        archive_entry_sparse_add_entry(entry,
            sb->offset, sb->remaining);
    }
  }

  if (r == ARCHIVE_OK && archive_entry_filetype(entry) == AE_IFREG) {
    /*
     * "Regular" entry with trailing '/' is really
     * directory: This is needed for certain old tar
     * variants and even for some broken newer ones.
     */
    if ((wp = archive_entry_pathname_w(entry)) != NULL) {
      l = wcslen(wp);
      if (l > 0 && wp[l - 1] == L'/') {
        archive_entry_set_filetype(entry, AE_IFDIR);
        tar->entry_bytes_remaining = 0;
        tar->entry_padding = 0;
      }
    } else if ((p = archive_entry_pathname(entry)) != NULL) {
      l = strlen(p);
      if (l > 0 && p[l - 1] == '/') {
        archive_entry_set_filetype(entry, AE_IFDIR);
        tar->entry_bytes_remaining = 0;
        tar->entry_padding = 0;
      }
    }
  }
  return (r);
}

static int
archive_read_format_tar_read_data(struct archive_read *a,
    const void **buff, size_t *size, int64_t *offset)
{
  ssize_t bytes_read;
  struct tar *tar;
  struct sparse_block *p;

  tar = (struct tar *)(a->format->data);

  for (;;) {
    /* Remove exhausted entries from sparse list. */
    while (tar->sparse_list != NULL &&
        tar->sparse_list->remaining == 0) {
      p = tar->sparse_list;
      tar->sparse_list = p->next;
      free(p);
    }

    if (tar->entry_bytes_unconsumed) {
      __archive_read_consume(a, tar->entry_bytes_unconsumed);
      tar->entry_bytes_unconsumed = 0;
    }

    /* If we're at end of file, return EOF. */
    if (tar->sparse_list == NULL ||
        tar->entry_bytes_remaining == 0) {
      int64_t request = tar->entry_bytes_remaining +
          tar->entry_padding;

      if (__archive_read_consume(a, request) != request)
        return (ARCHIVE_FATAL);
      tar->entry_padding = 0;
      *buff = NULL;
      *size = 0;
      *offset = tar->disk_size;
      return (ARCHIVE_EOF);
    }

    *buff = __archive_read_ahead(a, 1, &bytes_read);
    if (*buff == NULL) {
      archive_set_error(&a->archive, ARCHIVE_ERRNO_MISC,
          "Truncated tar archive"
          " detected while reading data");
      return (ARCHIVE_FATAL);
    }
    if (bytes_read > tar->entry_bytes_remaining)
      bytes_read = (ssize_t)tar->entry_bytes_remaining;
    /* Don't read more than is available in the
     * current sparse block. */
    if (tar->sparse_list->remaining < bytes_read)
      bytes_read = (ssize_t)tar->sparse_list->remaining;
    *size = bytes_read;
    *offset = tar->sparse_list->offset;
    tar->sparse_list->remaining -= bytes_read;
    tar->sparse_list->offset += bytes_read;
    tar->entry_bytes_remaining -= bytes_read;
    tar->entry_bytes_unconsumed = bytes_read;

    if (!tar->sparse_list->hole)
      return (ARCHIVE_OK);
    /* Current is hole data and skip this. */
  }
}

static int
archive_read_format_tar_skip(struct archive_read *a)
{
  int64_t request;
  struct tar* tar;

  tar = (struct tar *)(a->format->data);

  request = tar->entry_bytes_remaining + tar->entry_padding +
      tar->entry_bytes_unconsumed;

  if (__archive_read_consume(a, request) != request)
    return (ARCHIVE_FATAL);

  tar->entry_bytes_remaining = 0;
  tar->entry_bytes_unconsumed = 0;
  tar->entry_padding = 0;

  /* Free the sparse list. */
  gnu_clear_sparse_list(tar);

  return (ARCHIVE_OK);
}

/*
 * This function resets the accumulated state while reading
 * a header.
 */
static void
tar_reset_header_state(struct tar *tar)
{
  tar->pax_hdrcharset_utf8 = 1;
  tar->sparse_gnu_attributes_seen = 0;
  archive_string_empty(&(tar->entry_gname));
  archive_string_empty(&(tar->entry_pathname));
  archive_string_empty(&(tar->entry_pathname_override));
  archive_string_empty(&(tar->entry_uname));
  archive_string_empty(&tar->entry_linkpath);
}

/*
 * This function reads and interprets all of the headers associated
 * with a single entry.
 */
static int
tar_read_header(struct archive_read *a, struct tar *tar,
    struct archive_entry *entry, int64_t *unconsumed)
{
  ssize_t bytes;
  int err = ARCHIVE_OK, err2;
  int eof_fatal = 0; /* EOF is okay at some points... */
  const char *h;
  const struct archive_entry_header_ustar *header;
  const struct archive_entry_header_gnutar *gnuheader;

  /* Bitmask of what header types we've seen. */
  int32_t seen_headers = 0;
  static const int32_t seen_A_header = 1;
  static const int32_t seen_g_header = 2;
  static const int32_t seen_K_header = 4;
  static const int32_t seen_L_header = 8;
  static const int32_t seen_V_header = 16;
  static const int32_t seen_x_header = 32; /* Also X */
  static const int32_t seen_mac_metadata = 512;

  tar_reset_header_state(tar);

  /* Ensure format is set. */
  if (a->archive.archive_format_name == NULL) {
    a->archive.archive_format = ARCHIVE_FORMAT_TAR;
    a->archive.archive_format_name = "tar";
  }

  /*
   * TODO: Write global/default pax options into
   * 'entry' struct here before overwriting with
   * file-specific options.
   */

  /* Loop over all the headers needed for the next entry */
  for (;;) {

    /* Find the next valid header record. */
    while (1) {
      if (tar_flush_unconsumed(a, unconsumed) != ARCHIVE_OK) {
        return (ARCHIVE_FATAL);
      }

      /* Read 512-byte header record */
      h = __archive_read_ahead(a, 512, &bytes);
      if (bytes == 0) { /* EOF at a block boundary. */
        if (eof_fatal) {
          /* We've read a special header already;
           * if there's no regular header, then this is
           * a premature EOF. */
          archive_set_error(&a->archive, EINVAL,
                "Damaged tar archive (end-of-archive within a sequence of headers)");
          return (ARCHIVE_FATAL);
        } else {
          return (ARCHIVE_EOF);
        }
      }
      if (h == NULL) {  /* Short block at EOF; this is bad. */
        archive_set_error(&a->archive,
            ARCHIVE_ERRNO_FILE_FORMAT,
            "Truncated tar archive"
            " detected while reading next header");
        return (ARCHIVE_FATAL);
      }
      *unconsumed += 512;

      if (h[0] == 0 && archive_block_is_null(h)) {
        /* We found a NULL block which indicates end-of-archive */

        if (tar->read_concatenated_archives) {
          /* We're ignoring NULL blocks, so keep going. */
          continue;
        }

        /* Try to consume a second all-null record, as well. */
        /* If we can't, that's okay. */
        tar_flush_unconsumed(a, unconsumed);
        h = __archive_read_ahead(a, 512, NULL);
        if (h != NULL && h[0] == 0 && archive_block_is_null(h))
            __archive_read_consume(a, 512);

        archive_clear_error(&a->archive);
        return (ARCHIVE_EOF);
      }

      /* This is NOT a null block, so it must be a valid header. */
      if (!checksum(a, h)) {
        if (tar_flush_unconsumed(a, unconsumed) != ARCHIVE_OK) {
          return (ARCHIVE_FATAL);
        }
        archive_set_error(&a->archive, EINVAL,
              "Damaged tar archive (bad header checksum)");
        /* If we've read some critical information (pax headers, etc)
         * and _then_ see a bad header, we can't really recover. */
        if (eof_fatal) {
          return (ARCHIVE_FATAL);
        } else {
          return (ARCHIVE_RETRY);
        }
      }
      break;
    }

    /* Determine the format variant. */
    header = (const struct archive_entry_header_ustar *)h;
    switch(header->typeflag[0]) {
    case 'A': /* Solaris tar ACL */
      if (seen_headers & seen_A_header) {
        archive_set_error(&a->archive, ARCHIVE_ERRNO_MISC,
              "Redundant 'A' header");
        return (ARCHIVE_FATAL);
      }
      seen_headers |= seen_A_header;
      a->archive.archive_format = ARCHIVE_FORMAT_TAR_PAX_INTERCHANGE;
      a->archive.archive_format_name = "Solaris tar";
      err2 = header_Solaris_ACL(a, tar, entry, h, unconsumed);
      break;
    case 'g': /* POSIX-standard 'g' header. */
      if (seen_headers & seen_g_header) {
        archive_set_error(&a->archive, ARCHIVE_ERRNO_MISC,
              "Redundant 'g' header");
        return (ARCHIVE_FATAL);
      }
      seen_headers |= seen_g_header;
      a->archive.archive_format = ARCHIVE_FORMAT_TAR_PAX_INTERCHANGE;
      a->archive.archive_format_name = "POSIX pax interchange format";
      err2 = header_pax_global(a, tar, entry, h, unconsumed);
      break;
    case 'K': /* Long link name (GNU tar, others) */
      if (seen_headers & seen_K_header) {
        archive_set_error(&a->archive, ARCHIVE_ERRNO_MISC,
              "Damaged archive: Redundant 'K' headers may cause linknames to be incorrect");
        err = err_combine(err, ARCHIVE_WARN);
      }
      seen_headers |= seen_K_header;
      a->archive.archive_format = ARCHIVE_FORMAT_TAR_GNUTAR;
      a->archive.archive_format_name = "GNU tar format";
      err2 = header_gnu_longlink(a, tar, entry, h, unconsumed);
      break;
    case 'L': /* Long filename (GNU tar, others) */
      if (seen_headers & seen_L_header) {
        archive_set_error(&a->archive, ARCHIVE_ERRNO_MISC,
              "Damaged archive: Redundant 'L' headers may cause filenames to be incorrect");
        err = err_combine(err, ARCHIVE_WARN);
      }
      seen_headers |= seen_L_header;
      a->archive.archive_format = ARCHIVE_FORMAT_TAR_GNUTAR;
      a->archive.archive_format_name = "GNU tar format";
      err2 = header_gnu_longname(a, tar, entry, h, unconsumed);
      break;
    case 'V': /* GNU volume header */
      if (seen_headers & seen_V_header) {
        archive_set_error(&a->archive, ARCHIVE_ERRNO_MISC,
              "Redundant 'V' header");
        err = err_combine(err, ARCHIVE_WARN);
      }
      seen_headers |= seen_V_header;
      a->archive.archive_format = ARCHIVE_FORMAT_TAR_GNUTAR;
      a->archive.archive_format_name = "GNU tar format";
      err2 = header_volume(a, tar, entry, h, unconsumed);
      break;
    case 'X': /* Used by SUN tar; same as 'x'. */
      if (seen_headers & seen_x_header) {
        archive_set_error(&a->archive, ARCHIVE_ERRNO_MISC,
              "Redundant 'X'/'x' header");
        return (ARCHIVE_FATAL);
      }
      seen_headers |= seen_x_header;
      a->archive.archive_format = ARCHIVE_FORMAT_TAR_PAX_INTERCHANGE;
      a->archive.archive_format_name =
        "POSIX pax interchange format (Sun variant)";
      err2 = header_pax_extension(a, tar, entry, h, unconsumed);
      break;
    case 'x': /* POSIX-standard 'x' header. */
      if (seen_headers & seen_x_header) {
        archive_set_error(&a->archive, ARCHIVE_ERRNO_MISC,
              "Redundant 'x' header");
        return (ARCHIVE_FATAL);
      }
      seen_headers |= seen_x_header;
      a->archive.archive_format = ARCHIVE_FORMAT_TAR_PAX_INTERCHANGE;
      a->archive.archive_format_name = "POSIX pax interchange format";
      err2 = header_pax_extension(a, tar, entry, h, unconsumed);
      break;
    default: /* Regular header: Legacy tar, GNU tar, or ustar */
      gnuheader = (const struct archive_entry_header_gnutar *)h;
      if (memcmp(gnuheader->magic, "ustar  \0", 8) == 0) {
        a->archive.archive_format = ARCHIVE_FORMAT_TAR_GNUTAR;
        a->archive.archive_format_name = "GNU tar format";
        err2 = header_gnutar(a, tar, entry, h, unconsumed);
      } else if (memcmp(header->magic, "ustar", 5) == 0) {
        if (a->archive.archive_format != ARCHIVE_FORMAT_TAR_PAX_INTERCHANGE) {
          a->archive.archive_format = ARCHIVE_FORMAT_TAR_USTAR;
          a->archive.archive_format_name = "POSIX ustar format";
        }
        err2 = header_ustar(a, tar, entry, h);
      } else {
        a->archive.archive_format = ARCHIVE_FORMAT_TAR;
        a->archive.archive_format_name = "tar (non-POSIX)";
        err2 = header_old_tar(a, tar, entry, h);
      }
      err = err_combine(err, err2);
      /* We return warnings or success as-is.  Anything else is fatal. */
      if (err < ARCHIVE_WARN) {
        return (ARCHIVE_FATAL);
      }
      /* Filename of the form `._filename` is an AppleDouble
       * extension entry.  The body is the macOS metadata blob;
       * this is followed by another entry with the actual
       * regular file data.
       * This design has two drawbacks:
       * = it's brittle; you might just have a file with such a name
       * = it duplicates any long pathname extensions
       *
       * TODO: This probably shouldn't be here at all.  Consider
       * just returning the contents as a regular entry here and
       * then dealing with it when we write data to disk.
       */
      if (tar->process_mac_extensions
          && ((seen_headers & seen_mac_metadata) == 0)
          && is_mac_metadata_entry(entry)) {
        err2 = read_mac_metadata_blob(a, entry, unconsumed);
        if (err2 < ARCHIVE_WARN) {
          return (ARCHIVE_FATAL);
        }
        err = err_combine(err, err2);
        /* Note: Other headers can appear again. */
        seen_headers = seen_mac_metadata;
        tar_reset_header_state(tar);
        break;
      }

      /* Reconcile GNU sparse attributes */
      if (tar->sparse_gnu_attributes_seen) {
        /* Only 'S' (GNU sparse) and ustar '0' regular files can be sparse */
        if (tar->filetype != 'S' && tar->filetype != '0') {
          archive_set_error(&a->archive, ARCHIVE_ERRNO_MISC,
                "Non-regular file cannot be sparse");
          return (ARCHIVE_WARN);
        } else if (tar->sparse_gnu_major == 0 &&
            tar->sparse_gnu_minor == 0) {
          /* Sparse map already parsed from 'x' header */
        } else if (tar->sparse_gnu_major == 0 &&
            tar->sparse_gnu_minor == 1) {
          /* Sparse map already parsed from 'x' header */
        } else if (tar->sparse_gnu_major == 1 &&
            tar->sparse_gnu_minor == 0) {
          /* Sparse map is prepended to file contents */
          ssize_t bytes_read;
          bytes_read = gnu_sparse_10_read(a, tar, unconsumed);
          if (bytes_read < 0)
            return ((int)bytes_read);
          tar->entry_bytes_remaining -= bytes_read;
        } else {
          archive_set_error(&a->archive,
                ARCHIVE_ERRNO_MISC,
                "Unrecognized GNU sparse file format");
          return (ARCHIVE_WARN);
        }
      }
      return (err);
    }

    /* We're between headers ... */
    err = err_combine(err, err2);
    if (err == ARCHIVE_FATAL)
      return (err);

    /* The GNU volume header and the pax `g` global header
     * are both allowed to be the only header in an
     * archive.  If we've seen any other header, a
     * following EOF is fatal. */
    if ((seen_headers & ~seen_V_header & ~seen_g_header) != 0) {
      eof_fatal = 1;
    }
  }
}

/*
 * Return true if block checksum is correct.
 */
static int
checksum(struct archive_read *a, const void *h)
{
  const unsigned char *bytes;
  const struct archive_entry_header_ustar *header;
  int check, sum;
  size_t i;

  (void)a; /* UNUSED */
  bytes = (const unsigned char *)h;
  header = (const struct archive_entry_header_ustar *)h;

  /* Checksum field must hold an octal number */
  for (i = 0; i < sizeof(header->checksum); ++i) {
    char c = header->checksum[i];
    if (c != ' ' && c != '\0' && (c < '0' || c > '7'))
      return 0;
  }

  /*
   * Test the checksum.  Note that POSIX specifies _unsigned_
   * bytes for this calculation.
   */
  sum = (int)tar_atol(header->checksum, sizeof(header->checksum));
  check = 0;
  for (i = 0; i < 148; i++)
    check += (unsigned char)bytes[i];
  for (; i < 156; i++)
    check += 32;
  for (; i < 512; i++)
    check += (unsigned char)bytes[i];
  if (sum == check)
    return (1);

  /*
   * Repeat test with _signed_ bytes, just in case this archive
   * was created by an old BSD, Solaris, or HP-UX tar with a
   * broken checksum calculation.
   */
  check = 0;
  for (i = 0; i < 148; i++)
    check += (signed char)bytes[i];
  for (; i < 156; i++)
    check += 32;
  for (; i < 512; i++)
    check += (signed char)bytes[i];
  if (sum == check)
    return (1);

#if DONT_FAIL_ON_CRC_ERROR
  /* Speed up fuzzing by pretending the checksum is always right. */
  return (1);
#else
  return (0);
#endif
}

/*
 * Return true if this block contains only nulls.
 */
static int
archive_block_is_null(const char *p)
{
  unsigned i;

  for (i = 0; i < 512; i++)
    if (*p++)
      return (0);
  return (1);
}

/*
 * Interpret 'A' Solaris ACL header
 */
static int
header_Solaris_ACL(struct archive_read *a, struct tar *tar,
    struct archive_entry *entry, const void *h, int64_t *unconsumed)
{
  const struct archive_entry_header_ustar *header;
  struct archive_string  acl_text;
  size_t size;
  int err, acl_type;
  uint64_t type;
  char *acl, *p;

  header = (const struct archive_entry_header_ustar *)h;
  size = (size_t)tar_atol(header->size, sizeof(header->size));
  archive_string_init(&acl_text);
  err = read_body_to_string(a, tar, &acl_text, h, unconsumed);
  if (err != ARCHIVE_OK) {
    archive_string_free(&acl_text);
    return (err);
  }

  /* TODO: Examine the first characters to see if this
   * is an AIX ACL descriptor.  We'll likely never support
   * them, but it would be polite to recognize and warn when
   * we do see them. */

  /* Leading octal number indicates ACL type and number of entries. */
  p = acl = acl_text.s;
  type = 0;
  while (*p != '\0' && p < acl + size) {
    if (*p < '0' || *p > '7') {
      archive_set_error(&a->archive, ARCHIVE_ERRNO_MISC,
          "Malformed Solaris ACL attribute (invalid digit)");
      archive_string_free(&acl_text);
      return(ARCHIVE_WARN);
    }
    type <<= 3;
    type += *p - '0';
    if (type > 077777777) {
      archive_set_error(&a->archive, ARCHIVE_ERRNO_MISC,
          "Malformed Solaris ACL attribute (count too large)");
      archive_string_free(&acl_text);
      return (ARCHIVE_WARN);
    }
    p++;
  }
  switch (type & ~0777777) {
  case 01000000:
    /* POSIX.1e ACL */
    acl_type = ARCHIVE_ENTRY_ACL_TYPE_ACCESS;
    break;
  case 03000000:
    /* NFSv4 ACL */
    acl_type = ARCHIVE_ENTRY_ACL_TYPE_NFS4;
    break;
  default:
    archive_set_error(&a->archive, ARCHIVE_ERRNO_MISC,
        "Malformed Solaris ACL attribute (unsupported type %llu)",
        (unsigned long long)type);
    archive_string_free(&acl_text);
    return (ARCHIVE_WARN);
  }
  p++;

  if (p >= acl + size) {
    archive_set_error(&a->archive, ARCHIVE_ERRNO_MISC,
        "Malformed Solaris ACL attribute (body overflow)");
    archive_string_free(&acl_text);
    return(ARCHIVE_WARN);
  }

  /* ACL text is null-terminated; find the end. */
  size -= (p - acl);
  acl = p;

  while (*p != '\0' && p < acl + size)
    p++;

  if (tar->sconv_acl == NULL) {
    tar->sconv_acl = archive_string_conversion_from_charset(
        &(a->archive), "UTF-8", 1);
    if (tar->sconv_acl == NULL) {
      archive_string_free(&acl_text);
      return (ARCHIVE_FATAL);
    }
  }
  archive_strncpy(&(tar->localname), acl, p - acl);
  err = archive_acl_from_text_l(archive_entry_acl(entry),
      tar->localname.s, acl_type, tar->sconv_acl);
  /* Workaround: Force perm_is_set() to be correct */
  /* If this bit were stored in the ACL, this wouldn't be needed */
  archive_entry_set_perm(entry, archive_entry_perm(entry));
  if (err != ARCHIVE_OK) {
    if (errno == ENOMEM) {
      archive_set_error(&a->archive, ENOMEM,
          "Can't allocate memory for ACL");
    } else
      archive_set_error(&a->archive, ARCHIVE_ERRNO_MISC,
          "Malformed Solaris ACL attribute (unparsable)");
  }
  archive_string_free(&acl_text);
  return (err);
}

/*
 * Interpret 'K' long linkname header.
 */
static int
header_gnu_longlink(struct archive_read *a, struct tar *tar,
    struct archive_entry *entry, const void *h, int64_t *unconsumed)
{
  int err;

  struct archive_string linkpath;
  archive_string_init(&linkpath);
  err = read_body_to_string(a, tar, &linkpath, h, unconsumed);
  if (err == ARCHIVE_OK) {
    archive_entry_set_link(entry, linkpath.s);
  }
  archive_string_free(&linkpath);
  return (err);
}

static int
set_conversion_failed_error(struct archive_read *a,
    struct archive_string_conv *sconv, const char *name)
{
  if (errno == ENOMEM) {
    archive_set_error(&a->archive, ENOMEM,
        "Can't allocate memory for %s", name);
    return (ARCHIVE_FATAL);
  }
  archive_set_error(&a->archive, ARCHIVE_ERRNO_FILE_FORMAT,
      "%s can't be converted from %s to current locale",
      name, archive_string_conversion_charset_name(sconv));
  return (ARCHIVE_WARN);
}

/*
 * Interpret 'L' long filename header.
 */
static int
header_gnu_longname(struct archive_read *a, struct tar *tar,
    struct archive_entry *entry, const void *h, int64_t *unconsumed)
{
  int err;
  struct archive_string longname;

  archive_string_init(&longname);
  err = read_body_to_string(a, tar, &longname, h, unconsumed);
  if (err == ARCHIVE_OK) {
    if (archive_entry_copy_pathname_l(entry, longname.s,
        archive_strlen(&longname), tar->sconv) != 0)
      err = set_conversion_failed_error(a, tar->sconv, "Pathname");
  }
  archive_string_free(&longname);
  return (err);
}

/*
 * Interpret 'V' GNU tar volume header.
 */
static int
header_volume(struct archive_read *a, struct tar *tar,
    struct archive_entry *entry, const void *h, int64_t *unconsumed)
{
  const struct archive_entry_header_ustar *header;
  int64_t size, to_consume;

  (void)a; /* UNUSED */
  (void)tar; /* UNUSED */
  (void)entry; /* UNUSED */

  header = (const struct archive_entry_header_ustar *)h;
  size = tar_atol(header->size, sizeof(header->size));
  if (size < 0 || size > (int64_t)pathname_limit) {
    return (ARCHIVE_FATAL);
  }
  to_consume = ((size + 511) & ~511);
  *unconsumed += to_consume;
  return (ARCHIVE_OK);
}

/*
 * Read the next `size` bytes into the provided string.
 * Null-terminate the string.
 */
static int
read_bytes_to_string(struct archive_read *a,
         struct archive_string *as, size_t size,
         int64_t *unconsumed) {
  const void *src;

  /* Fail if we can't make our buffer big enough. */
  if (archive_string_ensure(as, size + 1) == NULL) {
    archive_set_error(&a->archive, ENOMEM,
        "No memory");
    return (ARCHIVE_FATAL);
  }

  if (tar_flush_unconsumed(a, unconsumed) != ARCHIVE_OK) {
    return (ARCHIVE_FATAL);
  }

  /* Read the body into the string. */
  src = __archive_read_ahead(a, size, NULL);
  if (src == NULL) {
    archive_set_error(&a->archive, EINVAL,
        "Truncated archive"
        " detected while reading metadata");
    *unconsumed = 0;
    return (ARCHIVE_FATAL);
  }
  memcpy(as->s, src, size);
  as->s[size] = '\0';
  as->length = size;
  *unconsumed += size;
  return (ARCHIVE_OK);
}

/*
 * Read body of an archive entry into an archive_string object.
 */
static int
read_body_to_string(struct archive_read *a, struct tar *tar,
    struct archive_string *as, const void *h, int64_t *unconsumed)
{
  int64_t size;
  const struct archive_entry_header_ustar *header;
  int r;

  (void)tar; /* UNUSED */
  header = (const struct archive_entry_header_ustar *)h;
  size  = tar_atol(header->size, sizeof(header->size));
  if (size < 0 || size > entry_limit) {
    archive_set_error(&a->archive, EINVAL,
        "Special header has invalid size: %lld",
        (long long)size);
    return (ARCHIVE_FATAL);
  }
  if (size > (int64_t)pathname_limit) {
    archive_string_empty(as);
    int64_t to_consume = ((size + 511) & ~511);
    if (to_consume != __archive_read_consume(a, to_consume)) {
      return (ARCHIVE_FATAL);
    }
    archive_set_error(&a->archive, EINVAL,
        "Special header too large: %lld > 1MiB",
        (long long)size);
    return (ARCHIVE_WARN);
  }
  r = read_bytes_to_string(a, as, size, unconsumed);
  *unconsumed += 0x1ff & (-size);
  return(r);
}

/*
 * Parse out common header elements.
 *
 * This would be the same as header_old_tar, except that the
 * filename is handled slightly differently for old and POSIX
 * entries  (POSIX entries support a 'prefix').  This factoring
 * allows header_old_tar and header_ustar
 * to handle filenames differently, while still putting most of the
 * common parsing into one place.
 *
 * This is called _after_ ustar, GNU tar, Schily, etc, special
 * fields have already been parsed into the `tar` structure.
 * So we can make final decisions here about how to reconcile
 * size, mode, etc, information.
 */
static int
header_common(struct archive_read *a, struct tar *tar,
    struct archive_entry *entry, const void *h)
{
  const struct archive_entry_header_ustar *header;
  const char *existing_linkpath;
  const wchar_t *existing_wcs_linkpath;
  int     err = ARCHIVE_OK;

  header = (const struct archive_entry_header_ustar *)h;

  /* Parse out the numeric fields (all are octal) */

  /* Split mode handling: Set filetype always, perm only if not already set */
  archive_entry_set_filetype(entry,
      (mode_t)tar_atol(header->mode, sizeof(header->mode)));
  if (!archive_entry_perm_is_set(entry)) {
    archive_entry_set_perm(entry,
      (mode_t)tar_atol(header->mode, sizeof(header->mode)));
  }

  /* Set uid, gid, mtime if not already set */
  if (!archive_entry_uid_is_set(entry)) {
    archive_entry_set_uid(entry, tar_atol(header->uid, sizeof(header->uid)));
  }
  if (!archive_entry_gid_is_set(entry)) {
    archive_entry_set_gid(entry, tar_atol(header->gid, sizeof(header->gid)));
  }
  if (!archive_entry_mtime_is_set(entry)) {
    int64_t t64 = tar_atol(header->mtime, sizeof(header->mtime));
    time_t t = (time_t)t64;
    if ((int64_t)t != t64) { /* time_t overflowed */
      t = get_time_t_max();
    }
    archive_entry_set_mtime(entry, t, 0);
  }

  /* Reconcile the size info. */
  /* First, how big is the file on disk? */
  if ((tar->size_fields & TAR_SIZE_GNU_SPARSE_REALSIZE) != 0) {
    /* GNU sparse format 1.0 uses `GNU.sparse.realsize`
     * to hold the size of the file on disk. */
    tar->disk_size = tar->GNU_sparse_realsize;
  } else if ((tar->size_fields & TAR_SIZE_GNU_SPARSE_SIZE) != 0
       && (tar->sparse_gnu_major == 0)) {
    /* GNU sparse format 0.0 and 0.1 use `GNU.sparse.size`
     * to hold the size of the file on disk. */
    tar->disk_size = tar->GNU_sparse_size;
  } else if ((tar->size_fields & TAR_SIZE_SCHILY_SPARSE_REALSIZE) != 0) {
    tar->disk_size = tar->SCHILY_sparse_realsize;
  } else if ((tar->size_fields & TAR_SIZE_PAX_SIZE) != 0) {
    tar->disk_size = tar->pax_size;
  } else {
    /* There wasn't a suitable pax header, so use the ustar info */
    tar->disk_size = tar_atol(header->size, sizeof(header->size));
  }

  if (tar->disk_size < 0) {
    archive_set_error(&a->archive, ARCHIVE_ERRNO_MISC,
          "Tar entry has negative file size");
    return (ARCHIVE_FATAL);
  } else if (tar->disk_size > entry_limit) {
    archive_set_error(&a->archive, ARCHIVE_ERRNO_MISC,
          "Tar entry size overflow");
    return (ARCHIVE_FATAL);
  } else {
    archive_entry_set_size(entry, tar->disk_size);
  }

  /* Second, how big is the data in the archive? */
  if ((tar->size_fields & TAR_SIZE_GNU_SPARSE_SIZE) != 0
      && (tar->sparse_gnu_major == 1)) {
    /* GNU sparse format 1.0 uses `GNU.sparse.size`
     * to hold the size of the data in the archive. */
    tar->entry_bytes_remaining = tar->GNU_sparse_size;
  } else if ((tar->size_fields & TAR_SIZE_PAX_SIZE) != 0) {
    tar->entry_bytes_remaining = tar->pax_size;
  } else {
    tar->entry_bytes_remaining
      = tar_atol(header->size, sizeof(header->size));
  }
  if (tar->entry_bytes_remaining < 0) {
    tar->entry_bytes_remaining = 0;
    archive_set_error(&a->archive, ARCHIVE_ERRNO_MISC,
          "Tar entry has negative size");
    return (ARCHIVE_FATAL);
  } else if (tar->entry_bytes_remaining > entry_limit) {
    tar->entry_bytes_remaining = 0;
    archive_set_error(&a->archive, ARCHIVE_ERRNO_MISC,
          "Tar entry size overflow");
    return (ARCHIVE_FATAL);
  }

  /* Handle the tar type flag appropriately. */
  tar->filetype = header->typeflag[0];

  /*
   * TODO: If the linkpath came from Pax extension header, then
   * we should obey the hdrcharset_utf8 flag when converting these.
   */
  switch (tar->filetype) {
  case '1': /* Hard link */
    archive_entry_set_link_to_hardlink(entry);
    existing_wcs_linkpath = archive_entry_hardlink_w(entry);
    existing_linkpath = archive_entry_hardlink(entry);
    if ((existing_linkpath == NULL || existing_linkpath[0] == '\0')
        && (existing_wcs_linkpath == NULL || existing_wcs_linkpath[0] == '\0')) {
      struct archive_string linkpath;
      archive_string_init(&linkpath);
      archive_strncpy(&linkpath,
          header->linkname, sizeof(header->linkname));
      if (archive_entry_copy_hardlink_l(entry, linkpath.s,
                archive_strlen(&linkpath), tar->sconv) != 0) {
        err = set_conversion_failed_error(a, tar->sconv,
                  "Linkname");
        if (err == ARCHIVE_FATAL) {
          archive_string_free(&linkpath);
          return (err);
        }
      }
      archive_string_free(&linkpath);
    }
    /*
     * The following may seem odd, but: Technically, tar
     * does not store the file type for a "hard link"
     * entry, only the fact that it is a hard link.  So, I
     * leave the type zero normally.  But, pax interchange
     * format allows hard links to have data, which
     * implies that the underlying entry is a regular
     * file.
     */
    if (archive_entry_size(entry) > 0)
      archive_entry_set_filetype(entry, AE_IFREG);

    /*
     * A tricky point: Traditionally, tar readers have
     * ignored the size field when reading hardlink
     * entries, and some writers put non-zero sizes even
     * though the body is empty.  POSIX blessed this
     * convention in the 1988 standard, but broke with
     * this tradition in 2001 by permitting hardlink
     * entries to store valid bodies in pax interchange
     * format, but not in ustar format.  Since there is no
     * hard and fast way to distinguish pax interchange
     * from earlier archives (the 'x' and 'g' entries are
     * optional, after all), we need a heuristic.
     */
    if (archive_entry_size(entry) == 0) {
      /* If the size is already zero, we're done. */
    }  else if (a->archive.archive_format
        == ARCHIVE_FORMAT_TAR_PAX_INTERCHANGE) {
      /* Definitely pax extended; must obey hardlink size. */
    } else if (a->archive.archive_format == ARCHIVE_FORMAT_TAR
        || a->archive.archive_format == ARCHIVE_FORMAT_TAR_GNUTAR)
    {
      /* Old-style or GNU tar: we must ignore the size. */
      archive_entry_set_size(entry, 0);
      tar->entry_bytes_remaining = 0;
    } else if (archive_read_format_tar_bid(a, 50) > 50) {
      /*
       * We don't know if it's pax: If the bid
       * function sees a valid ustar header
       * immediately following, then let's ignore
       * the hardlink size.
       */
      archive_entry_set_size(entry, 0);
      tar->entry_bytes_remaining = 0;
    }
    /*
     * TODO: There are still two cases I'd like to handle:
     *   = a ustar non-pax archive with a hardlink entry at
     *     end-of-archive.  (Look for block of nulls following?)
     *   = a pax archive that has not seen any pax headers
     *     and has an entry which is a hardlink entry storing
     *     a body containing an uncompressed tar archive.
     * The first is worth addressing; I don't see any reliable
     * way to deal with the second possibility.
     */
    break;
  case '2': /* Symlink */
    archive_entry_set_link_to_symlink(entry);
    existing_wcs_linkpath = archive_entry_symlink_w(entry);
    existing_linkpath = archive_entry_symlink(entry);
    if ((existing_linkpath == NULL || existing_linkpath[0] == '\0')
        && (existing_wcs_linkpath == NULL || existing_wcs_linkpath[0] == '\0')) {
      struct archive_string linkpath;
      archive_string_init(&linkpath);
      archive_strncpy(&linkpath,
          header->linkname, sizeof(header->linkname));
      if (archive_entry_copy_symlink_l(entry, linkpath.s,
          archive_strlen(&linkpath), tar->sconv) != 0) {
        err = set_conversion_failed_error(a, tar->sconv,
            "Linkname");
        if (err == ARCHIVE_FATAL) {
          archive_string_free(&linkpath);
          return (err);
        }
      }
      archive_string_free(&linkpath);
    }
    archive_entry_set_filetype(entry, AE_IFLNK);
    archive_entry_set_size(entry, 0);
    tar->entry_bytes_remaining = 0;
    break;
  case '3': /* Character device */
    archive_entry_set_filetype(entry, AE_IFCHR);
    archive_entry_set_size(entry, 0);
    tar->entry_bytes_remaining = 0;
    break;
  case '4': /* Block device */
    archive_entry_set_filetype(entry, AE_IFBLK);
    archive_entry_set_size(entry, 0);
    tar->entry_bytes_remaining = 0;
    break;
  case '5': /* Dir */
    archive_entry_set_filetype(entry, AE_IFDIR);
    archive_entry_set_size(entry, 0);
    tar->entry_bytes_remaining = 0;
    break;
  case '6': /* FIFO device */
    archive_entry_set_filetype(entry, AE_IFIFO);
    archive_entry_set_size(entry, 0);
    tar->entry_bytes_remaining = 0;
    break;
  case 'D': /* GNU incremental directory type */
    /*
     * No special handling is actually required here.
     * It might be nice someday to preprocess the file list and
     * provide it to the client, though.
     */
    archive_entry_set_filetype(entry, AE_IFDIR);
    break;
  case 'M': /* GNU "Multi-volume" (remainder of file from last archive)*/
    /*
     * As far as I can tell, this is just like a regular file
     * entry, except that the contents should be _appended_ to
     * the indicated file at the indicated offset.  This may
     * require some API work to fully support.
     */
    break;
  case 'N': /* Old GNU "long filename" entry. */
    /* The body of this entry is a script for renaming
     * previously-extracted entries.  Ugh.  It will never
     * be supported by libarchive. */
    archive_entry_set_filetype(entry, AE_IFREG);
    break;
  case 'S': /* GNU sparse files */
    /*
     * Sparse files are really just regular files with
     * sparse information in the extended area.
     */
    /* FALLTHROUGH */
  case '0': /* ustar "regular" file */
    /* FALLTHROUGH */
  default: /* Non-standard file types */
    /*
     * Per POSIX: non-recognized types should always be
     * treated as regular files.
     */
    archive_entry_set_filetype(entry, AE_IFREG);
    break;
  }
  return (err);
}

/*
 * Parse out header elements for "old-style" tar archives.
 */
static int
header_old_tar(struct archive_read *a, struct tar *tar,
    struct archive_entry *entry, const void *h)
{
  const struct archive_entry_header_ustar *header;
  int err = ARCHIVE_OK, err2;

  /*
   * Copy filename over (to ensure null termination).
   * Skip if pathname was already set e.g. by header_gnu_longname()
   */
  header = (const struct archive_entry_header_ustar *)h;

  const char *existing_pathname = archive_entry_pathname(entry);
  const wchar_t *existing_wcs_pathname = archive_entry_pathname_w(entry);
  if ((existing_pathname == NULL || existing_pathname[0] == '\0')
      && (existing_wcs_pathname == NULL || existing_wcs_pathname[0] == '\0') &&
      archive_entry_copy_pathname_l(entry,
      header->name, sizeof(header->name), tar->sconv) != 0) {
    err = set_conversion_failed_error(a, tar->sconv, "Pathname");
    if (err == ARCHIVE_FATAL)
      return (err);
  }

  /* Grab rest of common fields */
  err2 = header_common(a, tar, entry, h);
  if (err > err2)
    err = err2;

  tar->entry_padding = 0x1ff & (-tar->entry_bytes_remaining);
  return (err);
}

/*
 * Is this likely an AppleDouble extension?
 */
static int
is_mac_metadata_entry(struct archive_entry *entry) {
  const char *p, *name;
  const wchar_t *wp, *wname;

  wname = wp = archive_entry_pathname_w(entry);
  if (wp != NULL) {
    /* Find the last path element. */
    for (; *wp != L'\0'; ++wp) {
      if (wp[0] == '/' && wp[1] != L'\0')
        wname = wp + 1;
    }
    /*
     * If last path element starts with "._", then
     * this is a Mac extension.
     */
    if (wname[0] == L'.' && wname[1] == L'_' && wname[2] != L'\0')
      return 1;
  } else {
    /* Find the last path element. */
    name = p = archive_entry_pathname(entry);
    if (p == NULL)
      return (ARCHIVE_FAILED);
    for (; *p != '\0'; ++p) {
      if (p[0] == '/' && p[1] != '\0')
        name = p + 1;
    }
    /*
     * If last path element starts with "._", then
     * this is a Mac extension.
     */
    if (name[0] == '.' && name[1] == '_' && name[2] != '\0')
      return 1;
  }
  /* Not a mac extension */
  return 0;
}

/*
 * Read a Mac AppleDouble-encoded blob of file metadata,
 * if there is one.
 *
 * TODO: In Libarchive 4, we should consider ripping this
 * out -- instead, return a file starting with `._` as
 * a regular file and let the client (or archive_write logic)
 * handle it.
 */
static int
read_mac_metadata_blob(struct archive_read *a,
    struct archive_entry *entry, int64_t *unconsumed)
{
  int64_t size;
  size_t msize;
  const void *data;

  /* Read the body as a Mac OS metadata blob. */
  size = archive_entry_size(entry);
  msize = (size_t)size;
  if (size < 0 || (uintmax_t)msize != (uintmax_t)size) {
    *unconsumed = 0;
    return (ARCHIVE_FATAL);
  }

  /* TODO: Should this merely skip the overlarge entry and
   * WARN?  Or is xattr_limit sufficiently large that we can
   * safely assume anything larger is malicious? */
  if (size > (int64_t)xattr_limit) {
    archive_set_error(&a->archive, ARCHIVE_ERRNO_MISC,
        "Oversized AppleDouble extension has size %llu > %llu",
        (unsigned long long)size,
        (unsigned long long)xattr_limit);
    return (ARCHIVE_FATAL);
  }

  /*
   * TODO: Look beyond the body here to peek at the next header.
   * If it's a regular header (not an extension header)
   * that has the wrong name, just return the current
   * entry as-is, without consuming the body here.
   * That would reduce the risk of us mis-identifying
   * an ordinary file that just happened to have
   * a name starting with "._".
   *
   * Q: Is the above idea really possible?  Even
   * when there are GNU or pax extension entries?
   */
  if (tar_flush_unconsumed(a, unconsumed) != ARCHIVE_OK) {
    return (ARCHIVE_FATAL);
  }
  data = __archive_read_ahead(a, msize, NULL);
  if (data == NULL) {
    archive_set_error(&a->archive, EINVAL,
        "Truncated archive"
        " detected while reading macOS metadata");
    *unconsumed = 0;
    return (ARCHIVE_FATAL);
  }
  archive_entry_clear(entry);
  archive_entry_copy_mac_metadata(entry, data, msize);
  *unconsumed = (msize + 511) & ~ 511;
  return (ARCHIVE_OK);
}

/*
 * Parse a file header for a pax extended archive entry.
 */
static int
header_pax_global(struct archive_read *a, struct tar *tar,
    struct archive_entry *entry, const void *h, int64_t *unconsumed)
{
  const struct archive_entry_header_ustar *header;
  int64_t size, to_consume;

  (void)a; /* UNUSED */
  (void)tar; /* UNUSED */
  (void)entry; /* UNUSED */

  header = (const struct archive_entry_header_ustar *)h;
  size = tar_atol(header->size, sizeof(header->size));
  if (size < 0 || size > entry_limit) {
    archive_set_error(&a->archive, EINVAL,
        "Special header has invalid size: %lld",
        (long long)size);
    return (ARCHIVE_FATAL);
  }
  to_consume = ((size + 511) & ~511);
  *unconsumed += to_consume;
  return (ARCHIVE_OK);
}

/*
 * Parse a file header for a Posix "ustar" archive entry.  This also
 * handles "pax" or "extended ustar" entries.
 *
 * In order to correctly handle pax attributes (which precede this),
 * we have to skip parsing any field for which the entry already has
 * contents.
 */
static int
header_ustar(struct archive_read *a, struct tar *tar,
    struct archive_entry *entry, const void *h)
{
  const struct archive_entry_header_ustar *header;
  int err = ARCHIVE_OK, r;

  header = (const struct archive_entry_header_ustar *)h;

  /*
   * The name field is fixed-width and may not be NUL-terminated.
   * Use a temporary string only when prefix/name joining is required.
   */
  const char *existing_pathname = archive_entry_pathname(entry);
  const wchar_t *existing_wcs_pathname = archive_entry_pathname_w(entry);
  if ((existing_pathname == NULL || existing_pathname[0] == '\0')
      && (existing_wcs_pathname == NULL || existing_wcs_pathname[0] == '\0')) {
    struct archive_string as;
    const char *pathname;
    size_t pathname_length;

    archive_string_init(&as);
    if (header->prefix[0]) {
      archive_strncpy(&as, header->prefix, sizeof(header->prefix));
      if (as.s[archive_strlen(&as) - 1] != '/')
        archive_strappend_char(&as, '/');
      archive_strncat(&as, header->name, sizeof(header->name));
      pathname = as.s;
      pathname_length = archive_strlen(&as);
    } else {
      pathname = header->name;
      pathname_length = sizeof(header->name);
    }
    r = archive_entry_copy_pathname_l(entry, pathname,
        pathname_length, tar->sconv);
    archive_string_free(&as);
    if (r != 0) {
      err = set_conversion_failed_error(a, tar->sconv, "Pathname");
      if (err == ARCHIVE_FATAL)
        return (err);
    }
  }

  /* Handle rest of common fields. */
  r = header_common(a, tar, entry, h);
  if (r == ARCHIVE_FATAL)
    return (r);
  if (r < err)
    err = r;

  /* Handle POSIX ustar fields. */
  const char *existing_uname = archive_entry_uname(entry);
  if (existing_uname == NULL || existing_uname[0] == '\0') {
    if (archive_entry_copy_uname_l(entry,
        header->uname, sizeof(header->uname), tar->sconv) != 0) {
      err = set_conversion_failed_error(a, tar->sconv, "Uname");
      if (err == ARCHIVE_FATAL)
        return (err);
    }
  }

  const char *existing_gname = archive_entry_gname(entry);
  if (existing_gname == NULL || existing_gname[0] == '\0') {
    if (archive_entry_copy_gname_l(entry,
        header->gname, sizeof(header->gname), tar->sconv) != 0) {
      err = set_conversion_failed_error(a, tar->sconv, "Gname");
      if (err == ARCHIVE_FATAL)
        return (err);
    }
  }

  /* Parse out device numbers only for char and block specials. */
  if (header->typeflag[0] == '3' || header->typeflag[0] == '4') {
    if (!archive_entry_rdev_is_set(entry)) {
      archive_entry_set_rdevmajor(entry, (dev_t)
          tar_atol(header->rdevmajor, sizeof(header->rdevmajor)));
      archive_entry_set_rdevminor(entry, (dev_t)
          tar_atol(header->rdevminor, sizeof(header->rdevminor)));
    }
  } else {
    archive_entry_set_rdev(entry, 0);
  }

  tar->entry_padding = 0x1ff & (-tar->entry_bytes_remaining);

  return (err);
}

static int
header_pax_extension(struct archive_read *a, struct tar *tar,
    struct archive_entry *entry, const void *h, int64_t *unconsumed)
{
  /* Sanity checks: The largest `x` body I've ever heard of was
   * a little over 4MB.  So I doubt there has ever been a
   * well-formed archive with an `x` body over 1GiB.  Similarly,
   * it seems plausible that no single attribute has ever been
   * larger than 100MB.  So if we see a larger value here, it's
   * almost certainly a sign of a corrupted/malicious archive. */

  /* Maximum sane size for extension body: 1 GiB */
  /* This cannot be raised to larger than 8GiB without
   * exceeding the maximum size for a standard ustar
   * entry. */
  const int64_t ext_size_limit = 1024 * 1024 * (int64_t)1024;
  /* Maximum size for a single line/attr: 100 million characters */
  /* This cannot be raised to more than 2GiB without exceeding
   * a `size_t` on 32-bit platforms. */
  const size_t max_parsed_line_length = 99999999ULL;
  /* Largest attribute prolog:  size + name. */
  const size_t max_size_name = 512;

  /* Size and padding of the full extension body */
  int64_t ext_size, ext_padding;
  size_t line_length, value_length, name_length;
  ssize_t to_read, did_read;
  const struct archive_entry_header_ustar *header;
  const char *p, *attr_start, *name_start;
  struct archive_string_conv *sconv;
  struct archive_string *pas = NULL;
  struct archive_string attr_name;
  int err = ARCHIVE_OK, r;

  header = (const struct archive_entry_header_ustar *)h;
  ext_size  = tar_atol(header->size, sizeof(header->size));
  if (ext_size > entry_limit) {
    return (ARCHIVE_FATAL);
  }
  if (ext_size < 0) {
    archive_set_error(&a->archive, EINVAL,
          "pax extension header has invalid size: %lld",
          (long long)ext_size);
    return (ARCHIVE_FATAL);
  }

  ext_padding = 0x1ff & (-ext_size);
  if (ext_size > ext_size_limit) {
    /* Consume the pax extension body and return an error */
    if (ext_size + ext_padding != __archive_read_consume(a, ext_size + ext_padding)) {
      return (ARCHIVE_FATAL);
    }
    archive_set_error(&a->archive, EINVAL,
        "Ignoring oversized pax extensions: %lld > %lld",
        (long long)ext_size, (long long)ext_size_limit);
    return (ARCHIVE_WARN);
  }
  if (tar_flush_unconsumed(a, unconsumed) != ARCHIVE_OK) {
    return (ARCHIVE_FATAL);
  }

  /* Parse the size/name of each pax attribute in the body */
  archive_string_init(&attr_name);
  while (ext_size > 0) {
    /* Read enough bytes to parse the size/name of the next attribute */
    to_read = max_size_name;
    if (to_read > ext_size) {
      to_read = ext_size;
    }
    p = __archive_read_ahead(a, to_read, &did_read);
    if (p == NULL) { /* EOF */
      archive_set_error(&a->archive, EINVAL,
            "Truncated tar archive"
            " detected while reading pax attribute name");
      return (ARCHIVE_FATAL);
    }
    if (did_read > ext_size) {
      did_read = ext_size;
    }

    /* Parse size of attribute */
    line_length = 0;
    attr_start = p;
    while (1) {
      if (p >= attr_start + did_read) {
        archive_set_error(&a->archive, ARCHIVE_ERRNO_MISC,
              "Ignoring malformed pax attributes: overlarge attribute size field");
        *unconsumed += ext_size + ext_padding;
        return (ARCHIVE_WARN);
      }
      if (*p == ' ') {
        p++;
        break;
      }
      if (*p < '0' || *p > '9') {
        archive_set_error(&a->archive, ARCHIVE_ERRNO_MISC,
              "Ignoring malformed pax attributes: malformed attribute size field");
        *unconsumed += ext_size + ext_padding;
        return (ARCHIVE_WARN);
      }
      line_length *= 10;
      line_length += *p - '0';
      if (line_length > max_parsed_line_length) {
        archive_set_error(&a->archive, ARCHIVE_ERRNO_MISC,
              "Ignoring malformed pax attribute: size > %lld",
              (long long)max_parsed_line_length);
        *unconsumed += ext_size + ext_padding;
        return (ARCHIVE_WARN);
      }
      p++;
    }

    if ((int64_t)line_length > ext_size) {
        archive_set_error(&a->archive, ARCHIVE_ERRNO_MISC,
              "Ignoring malformed pax attribute:  %lld > %lld",
              (long long)line_length, (long long)ext_size);
        *unconsumed += ext_size + ext_padding;
        return (ARCHIVE_WARN);
    }

    /* Parse name of attribute */
    if (p >= attr_start + did_read
        || p >= attr_start + line_length
        || *p == '=') {
      archive_set_error(&a->archive, ARCHIVE_ERRNO_MISC,
            "Ignoring malformed pax attributes: empty name found");
      *unconsumed += ext_size + ext_padding;
      return (ARCHIVE_WARN);
    }
    name_start = p;
    while (1) {
      if (p >= attr_start + did_read || p >= attr_start + line_length) {
        archive_set_error(&a->archive, ARCHIVE_ERRNO_MISC,
              "Ignoring malformed pax attributes: overlarge attribute name");
        *unconsumed += ext_size + ext_padding;
        return (ARCHIVE_WARN);
      }
      if (*p == '=') {
        break;
      }
      p++;
    }
    name_length = p - name_start;
    p++; // Skip '='

    // Save the name before we consume it
    archive_strncpy(&attr_name, name_start, name_length);

    ext_size -= p - attr_start;
    value_length = line_length - (p - attr_start);

    /* Consume size, name, and `=` */
    *unconsumed += p - attr_start;
    if (tar_flush_unconsumed(a, unconsumed) != ARCHIVE_OK) {
      archive_string_free(&attr_name);
      return (ARCHIVE_FATAL);
    }

    if (value_length == 0) {
      archive_set_error(&a->archive, EINVAL,
            "Malformed pax attributes");
      *unconsumed += ext_size + ext_padding;
      archive_string_free(&attr_name);
      return (ARCHIVE_WARN);
    }

    /* pax_attribute will consume value_length - 1 */
    r = pax_attribute(a, tar, entry, attr_name.s, archive_strlen(&attr_name), value_length - 1, unconsumed);
    ext_size -= value_length - 1;

    // Release the allocated attr_name (either here or before every return in this function)
    archive_string_free(&attr_name);

    if (r < ARCHIVE_WARN) {
      *unconsumed += ext_size + ext_padding;
      return (r);
    }
    err = err_combine(err, r);

    /* Consume the `\n` that follows the pax attribute value. */
    if (tar_flush_unconsumed(a, unconsumed) != ARCHIVE_OK) {
      return (ARCHIVE_FATAL);
    }
    p = __archive_read_ahead(a, 1, &did_read);
    if (p == NULL) {
      archive_set_error(&a->archive, EINVAL,
            "Truncated tar archive"
            " detected while completing pax attribute");
      return (ARCHIVE_FATAL);
    }
    if (p[0] != '\n') {
      archive_set_error(&a->archive, EINVAL,
            "Malformed pax attributes");
      *unconsumed += ext_size + ext_padding;
      return (ARCHIVE_WARN);
    }
    ext_size -= 1;
    *unconsumed += 1;
    if (tar_flush_unconsumed(a, unconsumed) != ARCHIVE_OK) {
      return (ARCHIVE_FATAL);
    }
  }
  *unconsumed += ext_size + ext_padding;

  /*
   * Some PAX values -- pathname, linkpath, uname, gname --
   * can't be copied into the entry until we know the character
   * set to use:
   */
  if (!tar->pax_hdrcharset_utf8)
    /* PAX specified "BINARY", so use the default charset */
    sconv = tar->opt_sconv;
  else {
    /* PAX default UTF-8 */
    sconv = archive_string_conversion_from_charset(
        &(a->archive), "UTF-8", 1);
    if (sconv == NULL)
      return (ARCHIVE_FATAL);
    if (tar->compat_2x)
      archive_string_conversion_set_opt(sconv,
          SCONV_SET_OPT_UTF8_LIBARCHIVE2X);
  }

  /* Pathname */
  pas = NULL;
  if (archive_strlen(&(tar->entry_pathname_override)) > 0) {
    /* Prefer GNU.sparse.name attribute if present */
    /* GNU sparse files store a fake name under the standard
     * "pathname" key. */
    pas = &(tar->entry_pathname_override);
  } else if (archive_strlen(&(tar->entry_pathname)) > 0) {
    /* Use standard "pathname" PAX extension */
    pas = &(tar->entry_pathname);
  }
  if (pas != NULL) {
    if (archive_entry_copy_pathname_l(entry, pas->s,
        archive_strlen(pas), sconv) != 0) {
      err = set_conversion_failed_error(a, sconv, "Pathname");
      if (err == ARCHIVE_FATAL)
        return (err);
      /* Use raw name without conversion */
      archive_entry_copy_pathname(entry, pas->s);
    }
  }
  /* Uname */
  if (archive_strlen(&(tar->entry_uname)) > 0) {
    if (archive_entry_copy_uname_l(entry, tar->entry_uname.s,
        archive_strlen(&(tar->entry_uname)), sconv) != 0) {
      err = set_conversion_failed_error(a, sconv, "Uname");
      if (err == ARCHIVE_FATAL)
        return (err);
      /* Use raw name without conversion */
      archive_entry_copy_uname(entry, tar->entry_uname.s);
    }
  }
  /* Gname */
  if (archive_strlen(&(tar->entry_gname)) > 0) {
    if (archive_entry_copy_gname_l(entry, tar->entry_gname.s,
        archive_strlen(&(tar->entry_gname)), sconv) != 0) {
      err = set_conversion_failed_error(a, sconv, "Gname");
      if (err == ARCHIVE_FATAL)
        return (err);
      /* Use raw name without conversion */
      archive_entry_copy_gname(entry, tar->entry_gname.s);
    }
  }
  /* Linkpath */
  if (archive_strlen(&(tar->entry_linkpath)) > 0) {
    if (archive_entry_copy_link_l(entry, tar->entry_linkpath.s,
        archive_strlen(&(tar->entry_linkpath)), sconv) != 0) {
      err = set_conversion_failed_error(a, sconv, "Linkpath");
      if (err == ARCHIVE_FATAL)
        return (err);
      /* Use raw name without conversion */
      archive_entry_copy_link(entry, tar->entry_linkpath.s);
    }
  }

  /* Extension may have given us a corrected `entry_bytes_remaining` for
   * the main entry; update the padding appropriately. */
  tar->entry_padding = 0x1ff & (-tar->entry_bytes_remaining);
  return (err);
}

static int
pax_attribute_LIBARCHIVE_xattr(struct archive_entry *entry,
  const char *name, size_t name_length, const char *value, size_t value_length)
{
  char *name_decoded;
  void *value_decoded;
  size_t value_len;

  if (name_length < 1)
    return 3;

  /* URL-decode name */
  name_decoded = url_decode(name, name_length);
  if (name_decoded == NULL)
    return 2;

  /* Base-64 decode value */
  value_decoded = base64_decode(value, value_length, &value_len);
  if (value_decoded == NULL) {
    free(name_decoded);
    return 1;
  }

  archive_entry_xattr_add_entry(entry, name_decoded,
    value_decoded, value_len);

  free(name_decoded);
  free(value_decoded);
  return 0;
}

static int
pax_attribute_SCHILY_xattr(struct archive_entry *entry,
  const char *name, size_t name_length, const char *value, size_t value_length)
{
  if (name_length < 1 || name_length > 128) {
    return 1;
  }

  char * null_terminated_name = malloc(name_length + 1);
  if (null_terminated_name != NULL) {
    memcpy(null_terminated_name, name, name_length);
    null_terminated_name[name_length] = '\0';
    archive_entry_xattr_add_entry(entry, null_terminated_name, value, value_length);
    free(null_terminated_name);
  }

  return 0;
}

static int
pax_attribute_RHT_security_selinux(struct archive_entry *entry,
  const char *value, size_t value_length)
{
  archive_entry_xattr_add_entry(entry, "security.selinux",
            value, value_length);

  return 0;
}

static int
pax_attribute_SCHILY_acl(struct archive_read *a, struct tar *tar,
  struct archive_entry *entry, size_t value_length, int type)
{
  int r;
  const char *p;
  const char* errstr;

  switch (type) {
  case ARCHIVE_ENTRY_ACL_TYPE_ACCESS:
    errstr = "SCHILY.acl.access";
    break;
  case ARCHIVE_ENTRY_ACL_TYPE_DEFAULT:
    errstr = "SCHILY.acl.default";
    break;
  case ARCHIVE_ENTRY_ACL_TYPE_NFS4:
    errstr = "SCHILY.acl.ace";
    break;
  default:
    archive_set_error(&a->archive, ARCHIVE_ERRNO_MISC,
        "Unknown ACL type: %d", type);
    return(ARCHIVE_FATAL);
  }

  if (tar->sconv_acl == NULL) {
    tar->sconv_acl =
        archive_string_conversion_from_charset(
      &(a->archive), "UTF-8", 1);
    if (tar->sconv_acl == NULL)
      return (ARCHIVE_FATAL);
  }

  if (value_length > acl_limit) {
    __archive_read_consume(a, value_length);
    archive_set_error(&a->archive, ARCHIVE_ERRNO_MISC,
          "Unreasonably large ACL: %llu > %llu",
          (unsigned long long)value_length,
          (unsigned long long)acl_limit);
    return (ARCHIVE_WARN);
  }

  p = __archive_read_ahead(a, value_length, NULL);
  if (p == NULL) {
    archive_set_error(&a->archive, ARCHIVE_ERRNO_FILE_FORMAT,
          "Truncated tar archive "
          "detected while reading ACL data");
    return (ARCHIVE_FATAL);
  }

  r = archive_acl_from_text_nl(archive_entry_acl(entry), p, value_length,
      type, tar->sconv_acl);
  __archive_read_consume(a, value_length);
  /* Workaround: Force perm_is_set() to be correct */
  /* If this bit were stored in the ACL, this wouldn't be needed */
  archive_entry_set_perm(entry, archive_entry_perm(entry));
  if (r != ARCHIVE_OK) {
    if (r == ARCHIVE_FATAL) {
      archive_set_error(&a->archive, ENOMEM,
          "%s %s", "Can't allocate memory for",
          errstr);
      return (r);
    }
    archive_set_error(&a->archive,
        ARCHIVE_ERRNO_MISC, "%s %s", "Parse error:", errstr);
  }
  return (r);
}

static int
pax_attribute_read_time(struct archive_read *a, size_t value_length, __LA_TIME_T *ps, long *pn, int64_t *unconsumed) {
  struct archive_string as;
  int r;

  if (value_length > 128) {
    __archive_read_consume(a, value_length);
    *ps = 0;
    *pn = 0;
    return (ARCHIVE_FATAL);
  }

  archive_string_init(&as);
  r = read_bytes_to_string(a, &as, value_length, unconsumed);
  if (r < ARCHIVE_OK) {
    archive_string_free(&as);
    *ps = 0;
    *pn = 0;
    return (r);
  }

  int64_t sec = 0;
  pax_time(as.s, archive_strlen(&as), &sec, pn);
  archive_string_free(&as);

  if (sec == INT64_MIN) {
    *ps = 0;
    *pn = 0;
    return (ARCHIVE_WARN);
  } else {
    *ps = (__LA_TIME_T)sec;
  }
  return (ARCHIVE_OK);
}

static int
pax_attribute_read_number(struct archive_read *a, size_t value_length, int64_t *result) {
  struct archive_string as;
  int64_t unconsumed = 0;
  int r;

  if (value_length > 64) {
    __archive_read_consume(a, value_length);
    *result = 0;
    return (ARCHIVE_FATAL);
  }

  archive_string_init(&as);
  r = read_bytes_to_string(a, &as, value_length, &unconsumed);
  if (tar_flush_unconsumed(a, &unconsumed) != ARCHIVE_OK) {
    *result = 0;
    return (ARCHIVE_FATAL);
  }
  if (r < ARCHIVE_OK) {
    archive_string_free(&as);
    *result = 0;
    return (r);
  }

  *result = tar_atol10(as.s, archive_strlen(&as));
  archive_string_free(&as);
  if (*result < 0 || *result == INT64_MAX) {
    *result = INT64_MAX;
    return (ARCHIVE_WARN);
  }
  return (ARCHIVE_OK);
}

/*
 * Parse a single key=value attribute.
 *
 * POSIX reserves all-lowercase keywords.  Vendor-specific extensions
 * should always have keywords of the form "VENDOR.attribute" In
 * particular, it's quite feasible to support many different vendor
 * extensions here.  I'm using "LIBARCHIVE" for extensions unique to
 * this library.
 *
 * TODO: Investigate other vendor-specific extensions and see if
 * any of them look useful.
 */
static int
pax_attribute(struct archive_read *a, struct tar *tar, struct archive_entry *entry,
        const char *key, size_t key_length, size_t value_length, int64_t *unconsumed)
{
  int64_t t;
  long n;
  const char *p;
  ssize_t bytes_read;
  int err = ARCHIVE_OK;

  switch (key[0]) {
  case 'G':
    /* GNU.* extensions */
    if (key_length > 4 && memcmp(key, "GNU.", 4) == 0) {
      key += 4;
      key_length -= 4;

      /* GNU.sparse marks the existence of GNU sparse information */
      if (key_length == 6 && memcmp(key, "sparse", 6) == 0) {
        tar->sparse_gnu_attributes_seen = 1;
      }

      /* GNU.sparse.* extensions */
      else if (key_length > 7 && memcmp(key, "sparse.", 7) == 0) {
        tar->sparse_gnu_attributes_seen = 1;
        key += 7;
        key_length -= 7;

        /* GNU "0.0" sparse pax format. */
        if (key_length == 9 && memcmp(key, "numblocks", 9) == 0) {
          /* GNU.sparse.numblocks */
          tar->sparse_offset = -1;
          tar->sparse_numbytes = -1;
          tar->sparse_gnu_major = 0;
          tar->sparse_gnu_minor = 0;
        }
        else if (key_length == 6 && memcmp(key, "offset", 6) == 0) {
          /* GNU.sparse.offset */
          if ((err = pax_attribute_read_number(a, value_length, &t)) == ARCHIVE_OK) {
            tar->sparse_offset = t;
            if (tar->sparse_numbytes != -1) {
              if (gnu_add_sparse_entry(a, tar,
                   tar->sparse_offset, tar->sparse_numbytes)
                  != ARCHIVE_OK)
                return (ARCHIVE_FATAL);
              tar->sparse_offset = -1;
              tar->sparse_numbytes = -1;
            }
          }
          return (err);
        }
        else if (key_length == 8 && memcmp(key, "numbytes", 8) == 0) {
          /* GNU.sparse.numbytes */
          if ((err = pax_attribute_read_number(a, value_length, &t)) == ARCHIVE_OK) {
            tar->sparse_numbytes = t;
            if (tar->sparse_offset != -1) {
              if (gnu_add_sparse_entry(a, tar,
                   tar->sparse_offset, tar->sparse_numbytes)
                  != ARCHIVE_OK)
                return (ARCHIVE_FATAL);
              tar->sparse_offset = -1;
              tar->sparse_numbytes = -1;
            }
          }
          return (err);
        }
        else if (key_length == 4 && memcmp(key, "size", 4) == 0) {
          /* GNU.sparse.size */
          /* This is either the size of stored entry OR the size of data on disk,
           * depending on which GNU sparse format version is in use.
           * Since pax attributes can be in any order, we may not actually
           * know at this point how to interpret this. */
          if ((err = pax_attribute_read_number(a, value_length, &t)) == ARCHIVE_OK) {
            tar->GNU_sparse_size = t;
            tar->size_fields |= TAR_SIZE_GNU_SPARSE_SIZE;
          }
          return (err);
        }

        /* GNU "0.1" sparse pax format. */
        else if (key_length == 3 && memcmp(key, "map", 3) == 0) {
          /* GNU.sparse.map */
          tar->sparse_gnu_major = 0;
          tar->sparse_gnu_minor = 1;
          if (value_length > sparse_map_limit) {
            archive_set_error(&a->archive, ARCHIVE_ERRNO_MISC,
                  "Unreasonably large sparse map: %llu > %llu",
                  (unsigned long long)value_length,
                  (unsigned long long)sparse_map_limit);
            err = ARCHIVE_FAILED;
          } else {
            p = __archive_read_ahead(a, value_length, &bytes_read);
            if (p == NULL) {
              archive_set_error(&a->archive, EINVAL,
                    "Truncated archive"
                    " detected while reading GNU sparse data");
              return (ARCHIVE_FATAL);
            }
            if (gnu_sparse_01_parse(a, tar, p, value_length) != ARCHIVE_OK) {
              err = ARCHIVE_WARN;
            }
          }
          __archive_read_consume(a, value_length);
          return (err);
        }

        /* GNU "1.0" sparse pax format */
        else if (key_length == 5 && memcmp(key, "major", 5) == 0) {
          /* GNU.sparse.major */
          if ((err = pax_attribute_read_number(a, value_length, &t)) == ARCHIVE_OK
              && t >= 0
              && t <= 10) {
            tar->sparse_gnu_major = (int)t;
          }
          return (err);
        }
        else if (key_length == 5 && memcmp(key, "minor", 5) == 0) {
          /* GNU.sparse.minor */
          if ((err = pax_attribute_read_number(a, value_length, &t)) == ARCHIVE_OK
              && t >= 0
              && t <= 10) {
            tar->sparse_gnu_minor = (int)t;
          }
          return (err);
        }
        else if (key_length == 4 && memcmp(key, "name", 4) == 0) {
          /* GNU.sparse.name */
          /*
           * The real filename; when storing sparse
           * files, GNU tar puts a synthesized name into
           * the regular 'path' attribute in an attempt
           * to limit confusion. ;-)
           */
          if (value_length > pathname_limit) {
            *unconsumed += value_length;
            err = ARCHIVE_WARN;
          } else {
            err = read_bytes_to_string(a, &(tar->entry_pathname_override),
                     value_length, unconsumed);
          }
          return (err);
        }
        else if (key_length == 8 && memcmp(key, "realsize", 8) == 0) {
          /* GNU.sparse.realsize = size of file on disk */
          if ((err = pax_attribute_read_number(a, value_length, &t)) == ARCHIVE_OK) {
            tar->GNU_sparse_realsize = t;
            tar->size_fields |= TAR_SIZE_GNU_SPARSE_REALSIZE;
          }
          return (err);
        }
      }
    }
    break;
  case 'L':
    /* LIBARCHIVE extensions */
    if (key_length > 11 && memcmp(key, "LIBARCHIVE.", 11) == 0) {
      key_length -= 11;
      key += 11;

      /* TODO: Handle arbitrary extended attributes... */
      /*
        if (strcmp(key, "LIBARCHIVE.xxxxxxx") == 0)
          archive_entry_set_xxxxxx(entry, value);
      */
      if (key_length == 12 && memcmp(key, "creationtime", 12) == 0) {
        /* LIBARCHIVE.creationtime */
        __LA_TIME_T sec = 0;
        if ((err = pax_attribute_read_time(a, value_length, &sec, &n, unconsumed)) == ARCHIVE_OK) {
          archive_entry_set_birthtime(entry, sec, n);
        } else {
          archive_set_error(&a->archive,
                ARCHIVE_ERRNO_MISC,
                "Ignoring malformed pax creationtime");
        }
        return (err);
      }
      else if (key_length == 11 && memcmp(key, "symlinktype", 11) == 0) {
        /* LIBARCHIVE.symlinktype */
        if (value_length < 16) {
          p = __archive_read_ahead(a, value_length, &bytes_read);
          if (p == NULL) {
            archive_set_error(&a->archive, ARCHIVE_ERRNO_FILE_FORMAT,
                  "Truncated tar archive "
                  "detected while reading `symlinktype` attribute");
            return (ARCHIVE_FATAL);
          }
          if (value_length == 4 && memcmp(p, "file", 4) == 0) {
            archive_entry_set_symlink_type(entry,
                         AE_SYMLINK_TYPE_FILE);
          } else if (value_length == 3 && memcmp(p, "dir", 3) == 0) {
              archive_entry_set_symlink_type(entry,
                           AE_SYMLINK_TYPE_DIRECTORY);
          } else {
            archive_set_error(&a->archive, ARCHIVE_ERRNO_MISC,
                  "Unrecognized symlink type");
            err = ARCHIVE_WARN;
          }
        } else {
          archive_set_error(&a->archive, ARCHIVE_ERRNO_MISC,
                "symlink type is very long"
                "(longest recognized value is 4 bytes, this is %llu)",
                (unsigned long long)value_length);
          err = ARCHIVE_WARN;
        }
        __archive_read_consume(a, value_length);
        return (err);
      }
      else if (key_length > 6 && memcmp(key, "xattr.", 6) == 0) {
        key_length -= 6;
        key += 6;
        if (value_length > xattr_limit) {
          err = ARCHIVE_WARN;
        } else {
          p = __archive_read_ahead(a, value_length, &bytes_read);
          if (p == NULL) {
            archive_set_error(&a->archive, EINVAL,
                  "Truncated archive"
                  " detected while reading xattr information");
            return (ARCHIVE_FATAL);
          }
          if (pax_attribute_LIBARCHIVE_xattr(entry, key, key_length, p, value_length)) {
            /* TODO: Unable to parse xattr */
            err = ARCHIVE_WARN;
          }
        }
        __archive_read_consume(a, value_length);
        return (err);
      }
    }
    break;
  case 'R':
    /* GNU tar uses RHT.security header to store SELinux xattrs
     * SCHILY.xattr.security.selinux == RHT.security.selinux */
    if (key_length == 20 && memcmp(key, "RHT.security.selinux", 20) == 0) {
      if (value_length > xattr_limit) {
        archive_set_error(&a->archive, ARCHIVE_ERRNO_MISC,
              "Ignoring unreasonably large security.selinux attribute:"
              " %llu > %llu",
              (unsigned long long)value_length,
              (unsigned long long)xattr_limit);
        /* TODO: Should this be FAILED instead? */
        err = ARCHIVE_WARN;
      } else {
        p = __archive_read_ahead(a, value_length, &bytes_read);
        if (p == NULL) {
          archive_set_error(&a->archive, EINVAL,
                "Truncated archive"
                " detected while reading selinux data");
          return (ARCHIVE_FATAL);
        }
        if (pax_attribute_RHT_security_selinux(entry, p, value_length)) {
          /* TODO: Unable to parse xattr */
          err = ARCHIVE_WARN;
        }
      }
      __archive_read_consume(a, value_length);
      return (err);
    }
    break;
  case 'S':
    /* SCHILY.* extensions used by "star" archiver */
    if (key_length > 7 && memcmp(key, "SCHILY.", 7) == 0) {
      key_length -= 7;
      key += 7;

      if (key_length == 10 && memcmp(key, "acl.access", 10) == 0) {
        err = pax_attribute_SCHILY_acl(a, tar, entry, value_length,
                  ARCHIVE_ENTRY_ACL_TYPE_ACCESS);
        // TODO: Mark mode as set
        return (err);
      }
      else if (key_length == 11 && memcmp(key, "acl.default", 11) == 0) {
        err = pax_attribute_SCHILY_acl(a, tar, entry, value_length,
                  ARCHIVE_ENTRY_ACL_TYPE_DEFAULT);
        return (err);
      }
      else if (key_length == 7 && memcmp(key, "acl.ace", 7) == 0) {
        err = pax_attribute_SCHILY_acl(a, tar, entry, value_length,
                  ARCHIVE_ENTRY_ACL_TYPE_NFS4);
        // TODO: Mark mode as set
        return (err);
      }
      else if (key_length == 8 && memcmp(key, "devmajor", 8) == 0) {
        if ((err = pax_attribute_read_number(a, value_length, &t)) == ARCHIVE_OK) {
          archive_entry_set_rdevmajor(entry, (dev_t)t);
        }
        return (err);
      }
      else if (key_length == 8 && memcmp(key, "devminor", 8) == 0) {
        if ((err = pax_attribute_read_number(a, value_length, &t)) == ARCHIVE_OK) {
          archive_entry_set_rdevminor(entry, (dev_t)t);
        }
        return (err);
      }
      else if (key_length == 6 && memcmp(key, "fflags", 6) == 0) {
        if (value_length < fflags_limit) {
          p = __archive_read_ahead(a, value_length, &bytes_read);
          if (p == NULL) {
            /* Truncated archive */
            archive_set_error(&a->archive, EINVAL,
                  "Truncated archive"
                  " detected while reading SCHILY.fflags");
            return (ARCHIVE_FATAL);
          }
          archive_entry_copy_fflags_text_len(entry, p, value_length);
          err = ARCHIVE_OK;
        } else {
          /* Overlong fflags field */
          err = ARCHIVE_WARN;
        }
        __archive_read_consume(a, value_length);
        return (err);
      }
      else if (key_length == 3 && memcmp(key, "dev", 3) == 0) {
        if ((err = pax_attribute_read_number(a, value_length, &t)) == ARCHIVE_OK) {
          archive_entry_set_dev(entry, (dev_t)t);
        }
        return (err);
      }
      else if (key_length == 3 && memcmp(key, "ino", 3) == 0) {
        if ((err = pax_attribute_read_number(a, value_length, &t)) == ARCHIVE_OK) {
          archive_entry_set_ino(entry, t);
        }
        return (err);
      }
      else if (key_length == 5 && memcmp(key, "nlink", 5) == 0) {
        if ((err = pax_attribute_read_number(a, value_length, &t)) == ARCHIVE_OK) {
          archive_entry_set_nlink(entry, (unsigned int)t);
        }
        return (err);
      }
      else if (key_length == 8 && memcmp(key, "realsize", 8) == 0) {
        if ((err = pax_attribute_read_number(a, value_length, &t)) == ARCHIVE_OK) {
          tar->SCHILY_sparse_realsize = t;
          tar->size_fields |= TAR_SIZE_SCHILY_SPARSE_REALSIZE;
        }
        return (err);
      }
      /* TODO: Is there a SCHILY.sparse.size similar to GNU.sparse.size ? */
      else if (key_length > 6 && memcmp(key, "xattr.", 6) == 0) {
        key_length -= 6;
        key += 6;
        if (value_length < xattr_limit) {
          p = __archive_read_ahead(a, value_length, &bytes_read);
          if (p == NULL) {
            archive_set_error(&a->archive, EINVAL,
                  "Truncated archive"
                  " detected while reading SCHILY.xattr");
            return (ARCHIVE_FATAL);
          }
          if (pax_attribute_SCHILY_xattr(entry, key, key_length, p, value_length)) {
            /* TODO: Unable to parse xattr */
            err = ARCHIVE_WARN;
          }
        } else {
          archive_set_error(&a->archive, ARCHIVE_ERRNO_MISC,
                "Unreasonably large xattr: %llu > %llu",
                (unsigned long long)value_length,
                (unsigned long long)xattr_limit);
          err = ARCHIVE_WARN;
        }
        __archive_read_consume(a, value_length);
        return (err);
      }
    }
    /* SUN.* extensions from Solaris tar */
    if (key_length > 4 && memcmp(key, "SUN.", 4) == 0) {
      key_length -= 4;
      key += 4;

      if (key_length == 9 && memcmp(key, "holesdata", 9) == 0) {
        /* SUN.holesdata */
        if (value_length < sparse_map_limit) {
          p = __archive_read_ahead(a, value_length, &bytes_read);
          if (p == NULL) {
            archive_set_error(&a->archive, EINVAL,
                  "Truncated archive"
                  " detected while reading SUN.holesdata");
            return (ARCHIVE_FATAL);
          }
          err = pax_attribute_SUN_holesdata(a, tar, entry, p, value_length);
          if (err < ARCHIVE_OK) {
            archive_set_error(&a->archive,
                  ARCHIVE_ERRNO_MISC,
                  "Parse error: SUN.holesdata");
          }
        } else {
          archive_set_error(&a->archive, ARCHIVE_ERRNO_MISC,
                "Unreasonably large sparse map: %llu > %llu",
                (unsigned long long)value_length,
                (unsigned long long)sparse_map_limit);
          err = ARCHIVE_FAILED;
        }
        __archive_read_consume(a, value_length);
        return (err);
      }
    }
    break;
  case 'a':
    if (key_length == 5 && memcmp(key, "atime", 5) == 0) {
      __LA_TIME_T sec = 0;
      if ((err = pax_attribute_read_time(a, value_length, &sec, &n, unconsumed)) == ARCHIVE_OK) {
        archive_entry_set_atime(entry, sec, n);
      } else {
        archive_set_error(&a->archive,
            ARCHIVE_ERRNO_MISC,
            "Ignoring malformed pax atime");
      }
      return (err);
    }
    break;
  case 'c':
    if (key_length == 5 && memcmp(key, "ctime", 5) == 0) {
      __LA_TIME_T sec = 0;
      if ((err = pax_attribute_read_time(a, value_length, &sec, &n, unconsumed)) == ARCHIVE_OK) {
        archive_entry_set_ctime(entry, sec, n);
      } else {
        archive_set_error(&a->archive,
            ARCHIVE_ERRNO_MISC,
            "Ignoring malformed pax ctime");
      }
      return (err);
    } else if (key_length == 7 && memcmp(key, "charset", 7) == 0) {
      /* TODO: Publish charset information in entry. */
    } else if (key_length == 7 && memcmp(key, "comment", 7) == 0) {
      /* TODO: Publish comment in entry. */
    }
    break;
  case 'g':
    if (key_length == 3 && memcmp(key, "gid", 3) == 0) {
      if ((err = pax_attribute_read_number(a, value_length, &t)) == ARCHIVE_OK) {
        archive_entry_set_gid(entry, t);
      }
      return (err);
    } else if (key_length == 5 && memcmp(key, "gname", 5) == 0) {
      if (value_length > guname_limit) {
        *unconsumed += value_length;
        err = ARCHIVE_WARN;
      } else {
        err = read_bytes_to_string(a, &(tar->entry_gname), value_length, unconsumed);
      }
      return (err);
    }
    break;
  case 'h':
    if (key_length == 10 && memcmp(key, "hdrcharset", 10) == 0) {
      if (value_length < 64) {
        p = __archive_read_ahead(a, value_length, &bytes_read);
        if (p == NULL) {
          archive_set_error(&a->archive, ARCHIVE_ERRNO_FILE_FORMAT,
                "Truncated tar archive "
                "detected while reading hdrcharset attribute");
          return (ARCHIVE_FATAL);
        }
        if (value_length == 6
            && memcmp(p, "BINARY", 6) == 0) {
          /* Binary  mode. */
          tar->pax_hdrcharset_utf8 = 0;
          err = ARCHIVE_OK;
        } else if (value_length == 23
             && memcmp(p, "ISO-IR 10646 2000 UTF-8", 23) == 0) {
          tar->pax_hdrcharset_utf8 = 1;
          err = ARCHIVE_OK;
        } else {
          /* TODO: Unrecognized character set */
          err  = ARCHIVE_WARN;
        }
      } else {
        archive_set_error(&a->archive, ARCHIVE_ERRNO_FILE_FORMAT,
              "hdrcharset attribute is unreasonably large (%llu bytes)",
              (unsigned long long)value_length);
        err = ARCHIVE_WARN;
      }
      __archive_read_consume(a, value_length);
      return (err);
    }
    break;
  case 'l':
    /* pax interchange doesn't distinguish hardlink vs. symlink. */
    if (key_length == 8 && memcmp(key, "linkpath", 8) == 0) {
      if (value_length > pathname_limit) {
        *unconsumed += value_length;
        err = ARCHIVE_WARN;
      } else {
        err = read_bytes_to_string(a, &tar->entry_linkpath, value_length, unconsumed);
      }
      return (err);
    }
    break;
  case 'm':
    if (key_length == 5 && memcmp(key, "mtime", 5) == 0) {
      __LA_TIME_T sec;
      if ((err = pax_attribute_read_time(a, value_length, &sec, &n, unconsumed)) == ARCHIVE_OK) {
        archive_entry_set_mtime(entry, sec, n);
      } else {
        archive_set_error(&a->archive,
            ARCHIVE_ERRNO_MISC,
            "Ignoring malformed pax mtime");
      }
      return (err);
    }
    break;
  case 'p':
    if (key_length == 4 && memcmp(key, "path", 4) == 0) {
      if (value_length > pathname_limit) {
        *unconsumed += value_length;
        err = ARCHIVE_WARN;
      } else {
        err = read_bytes_to_string(a, &(tar->entry_pathname), value_length, unconsumed);
      }
      return (err);
    }
    break;
  case 'r':
    /* POSIX has reserved 'realtime.*' */
    break;
  case 's':
    /* POSIX has reserved 'security.*' */
    /* Someday: if (strcmp(key, "security.acl") == 0) { ... } */
    if (key_length == 4 && memcmp(key, "size", 4) == 0) {
      /* "size" is the size of the data in the entry. */
      if ((err = pax_attribute_read_number(a, value_length, &t)) == ARCHIVE_OK) {
        tar->pax_size = t;
        tar->size_fields |= TAR_SIZE_PAX_SIZE;
      }
      else if (t == INT64_MAX) {
        /* Note: pax_attr_read_number returns INT64_MAX on overflow or < 0 */
        tar->entry_bytes_remaining = 0;
        archive_set_error(&a->archive,
            ARCHIVE_ERRNO_MISC,
            "Tar size attribute overflow");
        return (ARCHIVE_FATAL);
      }
      return (err);
    }
    break;
  case 'u':
    if (key_length == 3 && memcmp(key, "uid", 3) == 0) {
      if ((err = pax_attribute_read_number(a, value_length, &t)) == ARCHIVE_OK) {
        archive_entry_set_uid(entry, t);
      }
      return (err);
    } else if (key_length == 5 && memcmp(key, "uname", 5) == 0) {
      if (value_length > guname_limit) {
        *unconsumed += value_length;
        err = ARCHIVE_WARN;
      } else {
        err = read_bytes_to_string(a, &(tar->entry_uname), value_length, unconsumed);
      }
      return (err);
    }
    break;
  }

  /* Unrecognized key, just skip the entire value. */
  __archive_read_consume(a, value_length);
  return (err);
}



/*
 * Parse a decimal time value, which may include a fractional portion
 *
 * Sets ps to INT64_MIN on error, including syntax issues such as non-digits,
 * or a time value that's outside the range of time_t.
 */
static void
pax_time(const char *p, size_t length, int64_t *ps, long *pn)
{
  char digit;
  int64_t s;
  unsigned long l;
  int sign;
  int64_t limit, last_digit_limit;

  limit = INT64_MAX / 10;
  last_digit_limit = INT64_MAX % 10;

  if (length <= 0) {
    *ps = 0;
    *pn = 0;
    return;
  }
  s = 0;
  sign = 1;
  if (*p == '-') {
    sign = -1;
    p++;
    length--;
  }
  while (length > 0 && *p >= '0' && *p <= '9') {
    digit = *p - '0';
    if (s > limit ||
        (s == limit && digit > last_digit_limit)) {
      *ps = INT64_MIN;
      *pn = 0;
      return;
    }
    s = (s * 10) + digit;
    ++p;
    --length;
  }

  *ps = s * sign;

#if ARCHIVE_VERSION_NUMBER < 4000000
  /* Libarchive 4.0 will have __LA_TIME_T == int64_t, so
     this will be unnecessary. */
  /* Test whether it overflows __LA_TIME_T */
  __LA_TIME_T sec = (__LA_TIME_T)*ps;
  if ((int64_t)sec != *ps) {
    *ps = INT64_MIN;
    *pn = 0;
    return;
  }
#endif

  /* Calculate nanoseconds. */
  *pn = 0;

  if (length <= 0) {
    return;
  }

  /* Skip `.` */
  if (*p != '.') {
    *ps = INT64_MIN;
    *pn = 0;
    return;
  }
  ++p;
  --length;

  l = 100000000UL;
  do {
    if (length <= 0) {
      return;
    }
    if (*p >= '0' && *p <= '9') {
      *pn += (*p - '0') * l;
    } else {
      *ps = INT64_MIN;
      *pn = 0;
      return;
    }
    ++p;
    --length;
  } while (l /= 10);

  /* Ignore resolution beyond nanoseconds,
     but verify it's all decimal digits. */
  while (length > 0) {
    if (*p < '0' || *p > '9') {
      *ps = INT64_MIN;
      *pn = 0;
      return;
    }
    ++p;
    --length;
  }
}

/*
 * Parse GNU tar header
 */
static int
header_gnutar(struct archive_read *a, struct tar *tar,
    struct archive_entry *entry, const void *h, int64_t *unconsumed)
{
  const struct archive_entry_header_gnutar *header;
  int64_t t;
  int err = ARCHIVE_OK;

  /*
   * GNU header is like POSIX ustar, except 'prefix' is
   * replaced with some other fields. This also means the
   * filename is stored as in old-style archives.
   */

  /* Copy filename over (to ensure null termination). */
  header = (const struct archive_entry_header_gnutar *)h;
  const char *existing_pathname = archive_entry_pathname(entry);
  const wchar_t *existing_wcs_pathname = archive_entry_pathname_w(entry);
  if ((existing_pathname == NULL || existing_pathname[0] == '\0')
      && (existing_wcs_pathname == NULL || existing_wcs_pathname[0] == L'\0')) {
    if (archive_entry_copy_pathname_l(entry,
        header->name, sizeof(header->name), tar->sconv) != 0) {
      err = set_conversion_failed_error(a, tar->sconv, "Pathname");
      if (err == ARCHIVE_FATAL)
        return (err);
    }
  }

  /* Fields common to ustar and GNU */
  /* XXX Can the following be factored out since it's common
   * to ustar and gnu tar?  Is it okay to move it down into
   * header_common, perhaps?  */
  const char *existing_uname = archive_entry_uname(entry);
  if (existing_uname == NULL || existing_uname[0] == '\0') {
    if (archive_entry_copy_uname_l(entry,
        header->uname, sizeof(header->uname), tar->sconv) != 0) {
      err = set_conversion_failed_error(a, tar->sconv, "Uname");
      if (err == ARCHIVE_FATAL)
        return (err);
    }
  }

  const char *existing_gname = archive_entry_gname(entry);
  if (existing_gname == NULL || existing_gname[0] == '\0') {
    if (archive_entry_copy_gname_l(entry,
        header->gname, sizeof(header->gname), tar->sconv) != 0) {
      err = set_conversion_failed_error(a, tar->sconv, "Gname");
      if (err == ARCHIVE_FATAL)
        return (err);
    }
  }

  /* Parse out device numbers only for char and block specials */
  if (header->typeflag[0] == '3' || header->typeflag[0] == '4') {
    if (!archive_entry_rdev_is_set(entry)) {
      archive_entry_set_rdevmajor(entry, (dev_t)
          tar_atol(header->rdevmajor, sizeof(header->rdevmajor)));
      archive_entry_set_rdevminor(entry, (dev_t)
          tar_atol(header->rdevminor, sizeof(header->rdevminor)));
    }
  } else {
    archive_entry_set_rdev(entry, 0);
  }

  /* Grab GNU-specific fields. */
  if (!archive_entry_atime_is_set(entry)) {
    t = tar_atol(header->atime, sizeof(header->atime));
    if (t > 0)
      archive_entry_set_atime(entry, t, 0);
  }
  if (!archive_entry_ctime_is_set(entry)) {
    t = tar_atol(header->ctime, sizeof(header->ctime));
    if (t > 0)
      archive_entry_set_ctime(entry, t, 0);
  }

  if (header->realsize[0] != 0) {
    /* Treat as a synonym for the pax GNU.sparse.realsize attr */
    tar->GNU_sparse_realsize
        = tar_atol(header->realsize, sizeof(header->realsize));
    tar->size_fields |= TAR_SIZE_GNU_SPARSE_REALSIZE;
  }

  if (header->sparse[0].offset[0] != 0) {
    if (gnu_sparse_old_read(a, tar, header, unconsumed)
        != ARCHIVE_OK)
      return (ARCHIVE_FATAL);
  } else {
    if (header->isextended[0] != 0) {
      /* XXX WTF? XXX */
    }
  }

  /* Grab fields common to all tar variants. */
  err = header_common(a, tar, entry, h);
  if (err == ARCHIVE_FATAL)
    return (err);

  tar->entry_padding = 0x1ff & (-tar->entry_bytes_remaining);

  return (err);
}

static int
gnu_add_sparse_entry(struct archive_read *a, struct tar *tar,
    int64_t offset, int64_t remaining)
{
  struct sparse_block *p;

  p = calloc(1, sizeof(*p));
  if (p == NULL) {
    archive_set_error(&a->archive, ENOMEM, "Out of memory");
    return (ARCHIVE_FATAL);
  }
  if (tar->sparse_last != NULL)
    tar->sparse_last->next = p;
  else
    tar->sparse_list = p;
  tar->sparse_last = p;
  if (remaining < 0 || offset < 0 || offset > INT64_MAX - remaining) {
    archive_set_error(&a->archive, ARCHIVE_ERRNO_MISC, "Malformed sparse map data");
    return (ARCHIVE_FATAL);
  }
  p->offset = offset;
  p->remaining = remaining;
  return (ARCHIVE_OK);
}

static void
gnu_clear_sparse_list(struct tar *tar)
{
  struct sparse_block *p;

  while (tar->sparse_list != NULL) {
    p = tar->sparse_list;
    tar->sparse_list = p->next;
    free(p);
  }
  tar->sparse_last = NULL;
}

/*
 * GNU tar old-format sparse data.
 *
 * GNU old-format sparse data is stored in a fixed-field
 * format.  Offset/size values are 11-byte octal fields (same
 * format as 'size' field in ustart header).  These are
 * stored in the header, allocating subsequent header blocks
 * as needed.  Extending the header in this way is a pretty
 * severe POSIX violation; this design has earned GNU tar a
 * lot of criticism.
 */

static int
gnu_sparse_old_read(struct archive_read *a, struct tar *tar,
    const struct archive_entry_header_gnutar *header, int64_t *unconsumed)
{
  ssize_t bytes_read;
  const void *data;
  struct extended {
    struct gnu_sparse sparse[21];
    char  isextended[1];
    char  padding[7];
  };
  const struct extended *ext;

  if (gnu_sparse_old_parse(a, tar, header->sparse, 4) != ARCHIVE_OK)
    return (ARCHIVE_FATAL);
  if (header->isextended[0] == 0)
    return (ARCHIVE_OK);

  do {
    if (tar_flush_unconsumed(a, unconsumed) != ARCHIVE_OK) {
      return (ARCHIVE_FATAL);
    }
    data = __archive_read_ahead(a, 512, &bytes_read);
    if (data == NULL) {
      archive_set_error(&a->archive, ARCHIVE_ERRNO_FILE_FORMAT,
          "Truncated tar archive "
          "detected while reading sparse file data");
      return (ARCHIVE_FATAL);
    }
    *unconsumed = 512;
    ext = (const struct extended *)data;
    if (gnu_sparse_old_parse(a, tar, ext->sparse, 21) != ARCHIVE_OK)
      return (ARCHIVE_FATAL);
  } while (ext->isextended[0] != 0);
  if (tar->sparse_list != NULL)
    tar->entry_offset = tar->sparse_list->offset;
  return (ARCHIVE_OK);
}

static int
gnu_sparse_old_parse(struct archive_read *a, struct tar *tar,
    const struct gnu_sparse *sparse, int length)
{
  while (length > 0 && sparse->offset[0] != 0) {
    if (gnu_add_sparse_entry(a, tar,
        tar_atol(sparse->offset, sizeof(sparse->offset)),
        tar_atol(sparse->numbytes, sizeof(sparse->numbytes)))
        != ARCHIVE_OK)
      return (ARCHIVE_FATAL);
    sparse++;
    length--;
  }
  return (ARCHIVE_OK);
}

/*
 * GNU tar sparse format 0.0
 *
 * Beginning with GNU tar 1.15, sparse files are stored using
 * information in the pax extended header.  The GNU tar maintainers
 * have gone through a number of variations in the process of working
 * out this scheme; fortunately, they're all numbered.
 *
 * Sparse format 0.0 uses attribute GNU.sparse.numblocks to store the
 * number of blocks, and GNU.sparse.offset/GNU.sparse.numbytes to
 * store offset/size for each block.  The repeated instances of these
 * latter fields violate the pax specification (which frowns on
 * duplicate keys), so this format was quickly replaced.
 */

/*
 * GNU tar sparse format 0.1
 *
 * This version replaced the offset/numbytes attributes with
 * a single "map" attribute that stored a list of integers.  This
 * format had two problems: First, the "map" attribute could be very
 * long, which caused problems for some implementations.  More
 * importantly, the sparse data was lost when extracted by archivers
 * that didn't recognize this extension.
 */
static int
gnu_sparse_01_parse(struct archive_read *a, struct tar *tar, const char *p, size_t length)
{
  const char *e;
  int64_t offset = -1, size = -1;

  for (;;) {
    e = p;
    while (length > 0 && *e != ',') {
      if (*e < '0' || *e > '9')
        return (ARCHIVE_WARN);
      e++;
      length--;
    }
    if (offset < 0) {
      offset = tar_atol10(p, e - p);
      if (offset < 0)
        return (ARCHIVE_WARN);
    } else {
      size = tar_atol10(p, e - p);
      if (size < 0)
        return (ARCHIVE_WARN);
      if (gnu_add_sparse_entry(a, tar, offset, size)
          != ARCHIVE_OK)
        return (ARCHIVE_FATAL);
      offset = -1;
    }
    if (length == 0)
      return (ARCHIVE_OK);
    p = e + 1;
    length--;
  }
}

/*
 * GNU tar sparse format 1.0
 *
 * The idea: The offset/size data is stored as a series of base-10
 * ASCII numbers prepended to the file data, so that dearchivers that
 * don't support this format will extract the block map along with the
 * data and a separate post-process can restore the sparseness.
 *
 * Unfortunately, GNU tar 1.16 had a bug that added unnecessary
 * padding to the body of the file when using this format.  GNU tar
 * 1.17 corrected this bug without bumping the version number, so
 * it's not possible to support both variants.  This code supports
 * the later variant at the expense of not supporting the former.
 *
 * This variant also introduced the GNU.sparse.major/GNU.sparse.minor attributes.
 */

/*
 * Read the next line from the input, and parse it as a decimal
 * integer followed by '\n'.  Returns positive integer value or
 * negative on error.
 */
static int64_t
gnu_sparse_10_atol(struct archive_read *a, struct tar *tar,
    int64_t *remaining, int64_t *unconsumed)
{
  int64_t l, limit, last_digit_limit;
  const char *p;
  ssize_t bytes_read;
  int base, digit;

  base = 10;
  limit = INT64_MAX / base;
  last_digit_limit = INT64_MAX % base;

  /*
   * Skip any lines starting with '#'; GNU tar specs
   * don't require this, but they should.
   */
  do {
    bytes_read = readline(a, tar, &p,
      (ssize_t)tar_min(*remaining, 100), unconsumed);
    if (bytes_read <= 0)
      return (ARCHIVE_FATAL);
    *remaining -= bytes_read;
  } while (p[0] == '#');

  l = 0;
  while (bytes_read > 0) {
    if (*p == '\n')
      return (l);
    if (*p < '0' || *p >= '0' + base)
      return (ARCHIVE_WARN);
    digit = *p - '0';
    if (l > limit || (l == limit && digit > last_digit_limit))
      l = INT64_MAX; /* Truncate on overflow. */
    else
      l = (l * base) + digit;
    p++;
    bytes_read--;
  }
  /* TODO: Error message. */
  return (ARCHIVE_WARN);
}

/*
 * Returns length (in bytes) of the sparse data description
 * that was read.
 */
static int64_t
gnu_sparse_10_read(struct archive_read *a, struct tar *tar, int64_t *unconsumed)
{
  int64_t bytes_read, entries, offset, size, to_skip, remaining;

  /* Clear out the existing sparse list. */
  gnu_clear_sparse_list(tar);

  remaining = tar->entry_bytes_remaining;

  /* Parse entries. */
  entries = gnu_sparse_10_atol(a, tar, &remaining, unconsumed);
  if (entries < 0)
    return (ARCHIVE_FATAL);
  /* Parse the individual entries. */
  while (entries-- > 0) {
    /* Parse offset/size */
    offset = gnu_sparse_10_atol(a, tar, &remaining, unconsumed);
    if (offset < 0)
      return (ARCHIVE_FATAL);
    size = gnu_sparse_10_atol(a, tar, &remaining, unconsumed);
    if (size < 0)
      return (ARCHIVE_FATAL);
    /* Add a new sparse entry. */
    if (gnu_add_sparse_entry(a, tar, offset, size) != ARCHIVE_OK)
      return (ARCHIVE_FATAL);
  }
  /* Skip rest of block... */
  if (tar_flush_unconsumed(a, unconsumed) != ARCHIVE_OK) {
    return (ARCHIVE_FATAL);
  }
  bytes_read = tar->entry_bytes_remaining - remaining;
  to_skip = 0x1ff & -bytes_read;
  /* Fail if tar->entry_bytes_remaing would get negative */
  if (to_skip > remaining)
    return (ARCHIVE_FATAL);
  if (to_skip != __archive_read_consume(a, to_skip))
    return (ARCHIVE_FATAL);
  return (bytes_read + to_skip);
}

/*
 * Solaris pax extension for a sparse file. This is recorded with the
 * data and hole pairs. The way recording sparse information by Solaris'
 * pax simply indicates where data and sparse are, so the stored contents
 * consist of both data and hole.
 */
static int
pax_attribute_SUN_holesdata(struct archive_read *a, struct tar *tar,
  struct archive_entry *entry, const char *p, size_t length)
{
  const char *e;
  int64_t start, end;
  int hole = 1;

  (void)entry; /* UNUSED */

  end = 0;
  if (length <= 0)
    return (ARCHIVE_WARN);
  if (*p == ' ') {
    p++;
    length--;
  } else {
    return (ARCHIVE_WARN);
  }
  for (;;) {
    e = p;
    while (length > 0 && *e != ' ') {
      if (*e < '0' || *e > '9')
        return (ARCHIVE_WARN);
      e++;
      length--;
    }
    start = end;
    end = tar_atol10(p, e - p);
    if (end < 0)
      return (ARCHIVE_WARN);
    if (start < end) {
      if (gnu_add_sparse_entry(a, tar, start,
          end - start) != ARCHIVE_OK)
        return (ARCHIVE_FATAL);
      tar->sparse_last->hole = hole;
    }
    if (length == 0 || *e == '\n') {
      if (length == 0 && *e == '\n') {
        return (ARCHIVE_OK);
      } else {
        return (ARCHIVE_WARN);
      }
    }
    p = e + 1;
    length--;
    hole = hole == 0;
  }
}

/*-
 * Convert text->integer.
 *
 * Traditional tar formats (including POSIX) specify base-8 for
 * all of the standard numeric fields.  This is a significant limitation
 * in practice:
 *   = file size is limited to 8GB
 *   = rdevmajor and rdevminor are limited to 21 bits
 *   = uid/gid are limited to 21 bits
 *
 * There are two workarounds for this:
 *   = pax extended headers, which use variable-length string fields
 *   = GNU tar and STAR both allow either base-8 or base-256 in
 *      most fields.  The high bit is set to indicate base-256.
 *
 * On read, this implementation supports both extensions.
 */
static int64_t
tar_atol(const char *p, size_t char_cnt)
{
  /*
   * Technically, GNU tar considers a field to be in base-256
   * only if the first byte is 0xff or 0x80.
   */
  if (*p & 0x80)
    return (tar_atol256(p, char_cnt));
  return (tar_atol8(p, char_cnt));
}

/*
 * Note that this implementation does not (and should not!) obey
 * locale settings; you cannot simply substitute strtol here, since
 * it does obey locale.
 */
static int64_t
tar_atol_base_n(const char *p, size_t char_cnt, int base)
{
  int64_t l, maxval, limit, last_digit_limit;
  int digit, sign;

  maxval = INT64_MAX;
  limit = INT64_MAX / base;
  last_digit_limit = INT64_MAX % base;

  /* the pointer will not be dereferenced if char_cnt is zero
   * due to the way the && operator is evaluated.
   */
  while (char_cnt != 0 && (*p == ' ' || *p == '\t')) {
    p++;
    char_cnt--;
  }

  sign = 1;
  if (char_cnt != 0 && *p == '-') {
    sign = -1;
    p++;
    char_cnt--;

    maxval = INT64_MIN;
    limit = -(INT64_MIN / base);
    last_digit_limit = -(INT64_MIN % base);
  }

  l = 0;
  if (char_cnt != 0) {
    digit = *p - '0';
    while (digit >= 0 && digit < base  && char_cnt != 0) {
      if (l>limit || (l == limit && digit >= last_digit_limit)) {
        return maxval; /* Truncate on overflow. */
      }
      l = (l * base) + digit;
      digit = *++p - '0';
      char_cnt--;
    }
  }
  return (sign < 0) ? -l : l;
}

static int64_t
tar_atol8(const char *p, size_t char_cnt)
{
  return tar_atol_base_n(p, char_cnt, 8);
}

static int64_t
tar_atol10(const char *p, size_t char_cnt)
{
  return tar_atol_base_n(p, char_cnt, 10);
}

/*
 * Parse a base-256 integer.  This is just a variable-length
 * twos-complement signed binary value in big-endian order, except
 * that the high-order bit is ignored.  The values here can be up to
 * 12 bytes, so we need to be careful about overflowing 64-bit
 * (8-byte) integers.
 *
 * This code unashamedly assumes that the local machine uses 8-bit
 * bytes and twos-complement arithmetic.
 */
static int64_t
tar_atol256(const char *_p, size_t char_cnt)
{
  uint64_t l;
  const unsigned char *p = (const unsigned char *)_p;
  unsigned char c, neg;

  /* Extend 7-bit 2s-comp to 8-bit 2s-comp, decide sign. */
  c = *p;
  if (c & 0x40) {
    neg = 0xff;
    c |= 0x80;
    l = ~ARCHIVE_LITERAL_ULL(0);
  } else {
    neg = 0;
    c &= 0x7f;
    l = 0;
  }

  /* If more than 8 bytes, check that we can ignore
   * high-order bits without overflow. */
  while (char_cnt > sizeof(int64_t)) {
    --char_cnt;
    if (c != neg)
      return neg ? INT64_MIN : INT64_MAX;
    c = *++p;
  }

  /* c is first byte that fits; if sign mismatch, return overflow */
  if ((c ^ neg) & 0x80) {
    return neg ? INT64_MIN : INT64_MAX;
  }

  /* Accumulate remaining bytes. */
  while (--char_cnt > 0) {
    l = (l << 8) | c;
    c = *++p;
  }
  l = (l << 8) | c;
  /* Return signed twos-complement value. */
  return (int64_t)(l);
}

/*
 * Returns length of line (including trailing newline)
 * or negative on error.  'start' argument is updated to
 * point to first character of line.  This avoids copying
 * when possible.
 */
static ssize_t
readline(struct archive_read *a, struct tar *tar, const char **start,
    ssize_t limit, int64_t *unconsumed)
{
  ssize_t bytes_read;
  ssize_t total_size = 0;
  const void *p, *t;
  const char *s;

  if (tar_flush_unconsumed(a, unconsumed) != ARCHIVE_OK) {
    return (ARCHIVE_FATAL);
  }

  t = __archive_read_ahead(a, 1, &bytes_read);
  if (bytes_read <= 0 || t == NULL)
    return (ARCHIVE_FATAL);
  s = t;  /* Start of line? */
  p = memchr(t, '\n', bytes_read);
  /* If we found '\n' in the read buffer, return pointer to that. */
  if (p != NULL) {
    bytes_read = 1 + ((const char *)p) - s;
    if (bytes_read > limit) {
      archive_set_error(&a->archive,
          ARCHIVE_ERRNO_FILE_FORMAT,
          "Line too long");
      return (ARCHIVE_FATAL);
    }
    *unconsumed = bytes_read;
    *start = s;
    return (bytes_read);
  }
  *unconsumed = bytes_read;
  /* Otherwise, we need to accumulate in a line buffer. */
  for (;;) {
    if (total_size + bytes_read > limit) {
      archive_set_error(&a->archive,
          ARCHIVE_ERRNO_FILE_FORMAT,
          "Line too long");
      return (ARCHIVE_FATAL);
    }
    if (archive_string_ensure(&tar->line, total_size + bytes_read) == NULL) {
      archive_set_error(&a->archive, ENOMEM,
          "Can't allocate working buffer");
      return (ARCHIVE_FATAL);
    }
    memcpy(tar->line.s + total_size, t, bytes_read);
    tar_flush_unconsumed(a, unconsumed);
    total_size += bytes_read;
    /* If we found '\n', clean up and return. */
    if (p != NULL) {
      *start = tar->line.s;
      return (total_size);
    }
    /* Read some more. */
    t = __archive_read_ahead(a, 1, &bytes_read);
    if (bytes_read <= 0 || t == NULL)
      return (ARCHIVE_FATAL);
    s = t;  /* Start of line? */
    p = memchr(t, '\n', bytes_read);
    /* If we found '\n', trim the read. */
    if (p != NULL) {
      bytes_read = 1 + ((const char *)p) - s;
    }
    *unconsumed = bytes_read;
  }
}

/*
 * base64_decode - Base64 decode
 *
 * This accepts most variations of base-64 encoding, including:
 *    * with or without line breaks
 *    * with or without the final group padded with '=' or '_' characters
 * (The most economical Base-64 variant does not pad the last group and
 * omits line breaks; RFC1341 used for MIME requires both.)
 */
static char *
base64_decode(const char *s, size_t len, size_t *out_len)
{
  static const unsigned char decode_table[128] = {
    255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
    255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
    255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
    255, 255, 255, 255, 255, 255, 255, 62, 255, 255, 255, 63,
    52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 255, 255, 255, 255,
    255, 255, 255, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13,
    14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 255, 255,
    255, 255, 255, 255, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35,
    36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50,
    51, 255, 255, 255, 255, 255 };
  char *out, *d;
  const unsigned char *src = (const unsigned char *)s;

  /* Allocate enough space to hold the entire output. */
  /* Note that we may not use all of this... */
  out = malloc(len - len / 4 + 1);
  if (out == NULL) {
    *out_len = 0;
    return (NULL);
  }
  d = out;

  while (len > 0) {
    /* Collect the next group of (up to) four characters. */
    int v = 0;
    int group_size = 0;
    while (group_size < 4 && len > 0) {
      /* '=' or '_' padding indicates final group. */
      if (*src == '=' || *src == '_') {
        len = 0;
        break;
      }
      /* Skip illegal characters (including line breaks) */
      if (*src > 127 || *src < 32
          || decode_table[*src] == 0xff) {
        len--;
        src++;
        continue;
      }
      v <<= 6;
      v |= decode_table[*src++];
      len --;
      group_size++;
    }
    /* Align a short group properly. */
    v <<= 6 * (4 - group_size);
    /* Unpack the group we just collected. */
    switch (group_size) {
    case 4: d[2] = v & 0xff;
      /* FALLTHROUGH */
    case 3: d[1] = (v >> 8) & 0xff;
      /* FALLTHROUGH */
    case 2: d[0] = (v >> 16) & 0xff;
      break;
    case 1: /* this is invalid! */
      break;
    }
    d += group_size * 3 / 4;
  }

  *out_len = d - out;
  return (out);
}

static char *
url_decode(const char *in, size_t length)
{
  char *out, *d;
  const char *s;

  out = malloc(length + 1);
  if (out == NULL)
    return (NULL);
  for (s = in, d = out; length > 0 && *s != '\0'; ) {
    if (s[0] == '%' && length > 2) {
      /* Try to convert % escape */
      int digit1 = tohex(s[1]);
      int digit2 = tohex(s[2]);
      if (digit1 >= 0 && digit2 >= 0) {
        /* Looks good, consume three chars */
        s += 3;
        length -= 3;
        /* Convert output */
        *d++ = ((digit1 << 4) | digit2);
        continue;
      }
      /* Else fall through and treat '%' as normal char */
    }
    *d++ = *s++;
    --length;
  }
  *d = '\0';
  return (out);
}

static int
tohex(int c)
{
  if (c >= '0' && c <= '9')
    return (c - '0');
  else if (c >= 'A' && c <= 'F')
    return (c - 'A' + 10);
  else if (c >= 'a' && c <= 'f')
    return (c - 'a' + 10);
  else
    return (-1);
}

Coverage Report

Created: 2026-06-13 06:52