/* minigzip.c -- simulate gzip using the zlib compression library

 * Copyright (C) 1995-2006, 2010, 2011, 2016 Jean-loup Gailly

 * For conditions of distribution and use, see copyright notice in zlib.h

 */

/*

 * minigzip is a minimal implementation of the gzip utility. This is

 * only an example of using zlib and isn't meant to replace the

 * full-featured gzip. No attempt is made to deal with file systems

 * limiting names to 14 or 8+3 characters, etc... Error checking is

 * very limited. So use minigzip only for testing; use gzip for the

 * real thing.

 */

/* @(#) $Id$ */

#include "zlib.h"

#include <stdio.h>

#include <assert.h>

#include <string.h>

#include <stdlib.h>

#include <inttypes.h>

#ifdef USE_MMAP

#  include <sys/types.h>

#  include <sys/mman.h>

#  include <sys/stat.h>

#endif

#ifndef UNALIGNED_OK

#  include <malloc.h>

#endif

#if defined(WIN32) || defined(__CYGWIN__)

#  include <fcntl.h>

#  include <io.h>

#  define SET_BINARY_MODE(file) setmode(fileno(file), O_BINARY)

#else

#  define SET_BINARY_MODE(file)

#endif

#if defined(_MSC_VER) && _MSC_VER < 1900

#  define snprintf _snprintf

#endif

#if !defined(Z_HAVE_UNISTD_H) && !defined(_LARGEFILE64_SOURCE)

#ifndef WIN32 /* unlink already in stdio.h for WIN32 */

  extern int unlink (const char *);

#endif

#endif

#ifndef GZ_SUFFIX

#  define GZ_SUFFIX ".gz"

#endif

#define SUFFIX_LEN (sizeof(GZ_SUFFIX)-1)

#define BUFLEN      16384        /* read buffer size */

#define BUFLENW     (BUFLEN * 3) /* write buffer size */

#define MAX_NAME_LEN 1024

#ifdef Z_SOLO

/* for Z_SOLO, create simplified gz* functions using deflate and inflate */

#if defined(Z_HAVE_UNISTD_H) || defined(Z_LARGE)

#  include <unistd.h>       /* for unlink() */

#endif

void *myalloc (void *, unsigned, unsigned);

void myfree (void *, void *);

void *myalloc(void *q, unsigned n, unsigned m)

{

    (void)q;

#ifndef UNALIGNED_OK

    return memalign(16, n * m);

#else

    return calloc(n, m);

#endif

}

void myfree(void *q, void *p)

{

    (void)q;

    free(p);

}

typedef struct gzFile_s {

    FILE *file;

    int write;

    int err;

    const char *msg;

    z_stream strm;

    unsigned char *buf;

} *gzFile;

gzFile gzopen(const char *, const char *);

gzFile gzdopen(int, const char *);

gzFile gz_open (const char *, int, const char *);

gzFile gzopen(const char *path, const char *mode)

{

    return gz_open(path, -1, mode);

}

gzFile gzdopen(int fd, const char *mode)

{

    return gz_open(NULL, fd, mode);

}

gzFile gz_open(const char *path, int fd, const char *mode)

{

    gzFile gz;

    int ret;

    int level = Z_DEFAULT_COMPRESSION;

    const char *plevel = mode;

    gz = malloc(sizeof(struct gzFile_s));

    if (gz == NULL)

        return NULL;

    gz->write = strchr(mode, 'w') != NULL;

    gz->strm.zalloc = myalloc;

    gz->strm.zfree = myfree;

    gz->strm.opaque = NULL;

    gz->buf = malloc(gz->write ? BUFLENW : BUFLEN);

    if (gz->buf == NULL) {

        free(gz);

        return NULL;

    }

    while (*plevel) {

        if (*plevel >= '0' && *plevel <= '9') {

           level = *plevel - '0';

           break;

        }

        plevel++;

    }

    if (gz->write)

        ret = deflateInit2(&(gz->strm), level, 8, 15 + 16, 8, 0);

    else {

        gz->strm.next_in = NULL;

        gz->strm.avail_in = 0;

        ret = inflateInit2(&(gz->strm), 15 + 16);

    }

    if (ret != Z_OK) {

        free(gz);

        return NULL;

    }

    gz->file = path == NULL ? fdopen(fd, gz->write ? "wb" : "rb") :

                              fopen(path, gz->write ? "wb" : "rb");

    if (gz->file == NULL) {

        gz->write ? deflateEnd(&(gz->strm)) : inflateEnd(&(gz->strm));

        free(gz);

        return NULL;

    }

    gz->err = 0;

    gz->msg = "";

    return gz;

}

int gzwrite(gzFile, const void *, unsigned);

int gzwrite(gzFile gz, const void *buf, unsigned len)

{

    z_stream *strm;

    if (gz == NULL || !gz->write)

        return 0;

    strm = &(gz->strm);

    strm->next_in = (void *)buf;

    strm->avail_in = len;

    do {

        strm->next_out = gz->buf;

        strm->avail_out = BUFLENW;

        (void)deflate(strm, Z_NO_FLUSH);

        fwrite(gz->buf, 1, BUFLENW - strm->avail_out, gz->file);

    } while (strm->avail_out == 0);

    return len;

}

int gzread(gzFile, void *, unsigned);

int gzread(gzFile gz, void *buf, unsigned len)

{

    z_stream *strm;

    if (gz == NULL || gz->write || gz->err)

        return 0;

    strm = &(gz->strm);

    strm->next_out = buf;

    strm->avail_out = len;

    do {

        if (strm->avail_in == 0)

        {

            strm->next_in = gz->buf;

            strm->avail_in = (uint32_t)fread(gz->buf, 1, BUFLEN, gz->file);

        }

        if (strm->avail_in > 0)

        {

            int ret = inflate(strm, Z_NO_FLUSH);

            if (ret == Z_DATA_ERROR) {

                gz->err = ret;

                gz->msg = strm->msg;

                return 0;

            }

            else if (ret == Z_STREAM_END)

                inflateReset(strm);

        }

        else

            break;

    } while (strm->avail_out);

    return len - strm->avail_out;

}

int gzclose(gzFile);

int gzclose(gzFile gz)

{

    z_stream *strm;

    if (gz == NULL)

        return Z_STREAM_ERROR;

    strm = &(gz->strm);

    if (gz->write) {

        strm->next_in = NULL;

        strm->avail_in = 0;

        do {

            strm->next_out = gz->buf;

            strm->avail_out = BUFLENW;

            (void)deflate(strm, Z_FINISH);

            fwrite(gz->buf, 1, BUFLENW - strm->avail_out, gz->file);

        } while (strm->avail_out == 0);

        deflateEnd(strm);

    }

    else

        inflateEnd(strm);

    free(gz->buf);

    fclose(gz->file);

    free(gz);

    return Z_OK;

}

const char *gzerror(gzFile, int *);

const char *gzerror(gzFile gz, int *err)

{

    *err = gz->err;

    return gz->msg;

}

#endif

static char *prog;

int error            (const char *msg);

int gz_compress      (FILE   *in, gzFile out);

#ifdef USE_MMAP

int  gz_compress_mmap (FILE   *in, gzFile out);

#endif

void gz_uncompress    (gzFile in, FILE   *out);

int file_compress    (char  *file, char *mode);

int file_uncompress  (char  *file);

int  main             (int argc, char *argv[]);

/* ===========================================================================

 * Display error message and return

 */

int error(const char *msg)

{

    fprintf(stderr, "%s: %s\n", prog, msg);

    return 0;

}

/* ===========================================================================

 * Compress input to output then close both files.

 */

int gz_compress(FILE   *in, gzFile out)

{

    char buf[BUFLEN];

    int len;

    int err;

#ifdef USE_MMAP

    /* Try first compressing with mmap. If mmap fails (minigzip used in a

     * pipe), use the normal fread loop.

     */

    if (gz_compress_mmap(in, out) == Z_OK) return;

#endif

    /* Clear out the contents of buf before reading from the file to avoid

       MemorySanitizer: use-of-uninitialized-value warnings. */

    memset(buf, 0, sizeof(buf));

    for (;;) {

        len = (int)fread(buf, 1, sizeof(buf), in);

        if (ferror(in)) {

            perror("fread");

            return 0;

        }

        if (len == 0) break;

        if (gzwrite(out, buf, (unsigned)len) != len) error(gzerror(out, &err));

    }

    fclose(in);

    if (gzclose(out) != Z_OK) error("failed gzclose");

    return 0;

}

#ifdef USE_MMAP /* MMAP version, Miguel Albrecht <malbrech@eso.org> */

/* Try compressing the input file at once using mmap. Return Z_OK if

 * if success, Z_ERRNO otherwise.

 */

int gz_compress_mmap(FILE   *in, gzFile out)

{

    int len;

    int err;

    int ifd = fileno(in);

    caddr_t buf;    /* mmap'ed buffer for the entire input file */

    off_t buf_len;  /* length of the input file */

    struct stat sb;

    /* Determine the size of the file, needed for mmap: */

    if (fstat(ifd, &sb) < 0) return Z_ERRNO;

    buf_len = sb.st_size;

    if (buf_len <= 0) return Z_ERRNO;

    /* Now do the actual mmap: */

    buf = mmap((caddr_t) 0, buf_len, PROT_READ, MAP_SHARED, ifd, (off_t)0);

    if (buf == (caddr_t)(-1)) return Z_ERRNO;

    /* Compress the whole file at once: */

    len = gzwrite(out, (char *)buf, (unsigned)buf_len);

    if (len != (int)buf_len) error(gzerror(out, &err));

    munmap(buf, buf_len);

    fclose(in);

    if (gzclose(out) != Z_OK) error("failed gzclose");

    return Z_OK;

}

#endif /* USE_MMAP */

/* ===========================================================================

 * Uncompress input to output then close both files.

 */

void gz_uncompress(gzFile in, FILE   *out)

{

    char buf[BUFLENW];

    int len;

    int err;

    for (;;) {

        len = gzread(in, buf, sizeof(buf));

        if (len < 0) error (gzerror(in, &err));

        if (len == 0) break;

        if ((int)fwrite(buf, 1, (unsigned)len, out) != len) {

            error("failed fwrite");

        }

    }

    if (fclose(out)) error("failed fclose");

    if (gzclose(in) != Z_OK) error("failed gzclose");

}

/* ===========================================================================

 * Compress the given file: create a corresponding .gz file and remove the

 * original.

 */

int file_compress(char  *file, char  *mode)

{

    char outfile[MAX_NAME_LEN];

    FILE  *in;

    gzFile out;

    if (strlen(file) + strlen(GZ_SUFFIX) >= sizeof(outfile)) {

        fprintf(stderr, "%s: filename too long\n", prog);

        return 0;

    }

    snprintf(outfile, sizeof(outfile), "%s%s", file, GZ_SUFFIX);

    in = fopen(file, "rb");

    if (in == NULL) {

        perror(file);

        return 0;

    }

    out = gzopen(outfile, mode);

    if (out == NULL) {

        fprintf(stderr, "%s: can't gzopen %s\n", prog, outfile);

        return 0;

    }

    gz_compress(in, out);

    unlink(file);

    return 0;

}

/* ===========================================================================

 * Uncompress the given file and remove the original.

 */

int file_uncompress(char  *file)

{

    char buf[MAX_NAME_LEN];

    char *infile, *outfile;

    FILE  *out;

    gzFile in;

    size_t len = strlen(file);

    if (len + strlen(GZ_SUFFIX) >= sizeof(buf)) {

        fprintf(stderr, "%s: filename too long\n", prog);

        return 0;

    }

    snprintf(buf, sizeof(buf), "%s", file);

    if (len > SUFFIX_LEN && strcmp(file+len-SUFFIX_LEN, GZ_SUFFIX) == 0) {

        infile = file;

        outfile = buf;

        outfile[len-3] = '\0';

    } else {

        outfile = file;

        infile = buf;

        snprintf(buf + len, sizeof(buf) - len, "%s", GZ_SUFFIX);

    }

    in = gzopen(infile, "rb");

    if (in == NULL) {

        fprintf(stderr, "%s: can't gzopen %s\n", prog, infile);

        return 0;

    }

    out = fopen(outfile, "wb");

    if (out == NULL) {

        perror(file);

        return 0;

    }

    gz_uncompress(in, out);

    unlink(infile);

    return 0;

}

int LLVMFuzzerTestOneInput(const uint8_t *data, size_t dataLen) {

  char *inFileName = "/tmp/minigzip_fuzzer.out";

  char *outFileName = "/tmp/minigzip_fuzzer.out.gz";

  char outmode[20];

  FILE *in;

  char buf[BUFLEN];

  uint32_t offset = 0;

  /* Discard inputs larger than 1Mb. */

  static size_t kMaxSize = 1024 * 1024;

  if (dataLen < 1 || dataLen > kMaxSize)

    return 0;

  in = fopen(inFileName, "w");

  if (fwrite(data, 1, (unsigned)dataLen, in) != dataLen)

    error("failed fwrite");

  if (fclose(in))

    error("failed fclose");

  memset(outmode, 0, sizeof(outmode));

  snprintf(outmode, sizeof(outmode), "%s", "wb");

  /* Compression level: [0..9]. */

  outmode[2] = data[0] % 10;

  switch (data[0] % 4) {

  default:

  case 0:

    outmode[3] = 0;

    break;

  case 1:

    /* compress with Z_FILTERED */

    outmode[3] = 'f';

    break;

  case 2:

    /* compress with Z_HUFFMAN_ONLY */

    outmode[3] = 'h';

    break;

  case 3:

    /* compress with Z_RLE */

    outmode[3] = 'R';

    break;

  }

  file_compress(inFileName, outmode);

  file_uncompress(outFileName);

  /* Check that the uncompressed file matches the input data. */

  in = fopen(inFileName, "rb");

  if (in == NULL) {

    perror(inFileName);

    return 0;

  }

  memset(buf, 0, sizeof(buf));

  for (;;) {

    int len = (int)fread(buf, 1, sizeof(buf), in);

    if (ferror(in)) {

      perror("fread");

      return 0;

    }

    if (len == 0)

      break;

    assert(0 == memcmp(data + offset, buf, len));

    offset += len;

  }

  if (fclose(in))

    error("failed fclose");

  /* This function must return 0. */

  return 0;

}