/*

 * Copyright (C) Internet Systems Consortium, Inc. ("ISC")

 *

 * SPDX-License-Identifier: MPL-2.0

 *

 * This Source Code Form is subject to the terms of the Mozilla Public

 * License, v. 2.0. If a copy of the MPL was not distributed with this

 * file, you can obtain one at https://mozilla.org/MPL/2.0/.

 *

 * See the COPYRIGHT file distributed with this work for additional

 * information regarding copyright ownership.

 */

/*

 * Portions Copyright (c) 1987, 1993

 *      The Regents of the University of California.  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.

 * 3. Neither the name of the University nor the names of its contributors

 *    may be used to endorse or promote products derived from this software

 *    without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``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 REGENTS OR CONTRIBUTORS 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.

 */

/*! \file */

#include <errno.h>

#include <fcntl.h>

#include <inttypes.h>

#include <limits.h>

#include <stdbool.h>

#include <stdlib.h>

#include <sys/stat.h>

#include <sys/time.h>

#include <time.h>   /* Required for utimes on some platforms. */

#include <unistd.h> /* Required for mkstemp on NetBSD. */

#ifdef HAVE_SYS_MMAN_H

#include <sys/mman.h>

#endif /* ifdef HAVE_SYS_MMAN_H */

#include <isc/dir.h>

#include <isc/file.h>

#include <isc/log.h>

#include <isc/md.h>

#include <isc/mem.h>

#include <isc/random.h>

#include <isc/string.h>

#include <isc/time.h>

#include <isc/util.h>

#include "errno2result.h"

/*

 * XXXDCL As the API for accessing file statistics undoubtedly gets expanded,

 * it might be good to provide a mechanism that allows for the results

 * of a previous stat() to be used again without having to do another stat,

 * such as perl's mechanism of using "_" in place of a file name to indicate

 * that the results of the last stat should be used.  But then you get into

 * annoying MP issues.   BTW, Win32 has stat().

 */

static isc_result_t

file_stats(const char *file, struct stat *stats) {

  isc_result_t result = ISC_R_SUCCESS;

  REQUIRE(file != NULL);

  REQUIRE(stats != NULL);

  if (stat(file, stats) != 0) {

    result = isc__errno2result(errno);

  }

  return result;

}

static isc_result_t

fd_stats(int fd, struct stat *stats) {

  isc_result_t result = ISC_R_SUCCESS;

  REQUIRE(stats != NULL);

  if (fstat(fd, stats) != 0) {

    result = isc__errno2result(errno);

  }

  return result;

}

isc_result_t

isc_file_getsizefd(int fd, off_t *size) {

  isc_result_t result;

  struct stat stats;

  REQUIRE(size != NULL);

  result = fd_stats(fd, &stats);

  if (result == ISC_R_SUCCESS) {

    *size = stats.st_size;

  }

  return result;

}

isc_result_t

isc_file_mode(const char *file, mode_t *modep) {

  isc_result_t result;

  struct stat stats;

  REQUIRE(modep != NULL);

  result = file_stats(file, &stats);

  if (result == ISC_R_SUCCESS) {

    *modep = (stats.st_mode & 07777);

  }

  return result;

}

isc_result_t

isc_file_getmodtime(const char *file, isc_time_t *modtime) {

  isc_result_t result;

  struct stat stats;

  REQUIRE(file != NULL);

  REQUIRE(modtime != NULL);

  result = file_stats(file, &stats);

  if (result == ISC_R_SUCCESS) {

#if defined(HAVE_STAT_NSEC)

    isc_time_set(modtime, stats.st_mtime, stats.st_mtim.tv_nsec);

#else  /* if defined(HAVE_STAT_NSEC) */

    isc_time_set(modtime, stats.st_mtime, 0);

#endif /* if defined(HAVE_STAT_NSEC) */

  }

  return result;

}

isc_result_t

isc_file_getsize(const char *file, off_t *size) {

  isc_result_t result;

  struct stat stats;

  REQUIRE(file != NULL);

  REQUIRE(size != NULL);

  result = file_stats(file, &stats);

  if (result == ISC_R_SUCCESS) {

    *size = stats.st_size;

  }

  return result;

}

isc_result_t

isc_file_settime(const char *file, isc_time_t *when) {

  struct timeval times[2];

  REQUIRE(file != NULL && when != NULL);

  /*

   * tv_sec is at least a 32 bit quantity on all platforms we're

   * dealing with, but it is signed on most (all?) of them,

   * so we need to make sure the high bit isn't set.  This unfortunately

   * loses when either:

   *   * tv_sec becomes a signed 64 bit integer but long is 32 bits

   *  and isc_time_seconds > LONG_MAX, or

   *   * isc_time_seconds is changed to be > 32 bits but long is 32 bits

   *      and isc_time_seconds has at least 33 significant bits.

   */

  times[0].tv_sec = times[1].tv_sec = (long)isc_time_seconds(when);

  /*

   * Here is the real check for the high bit being set.

   */

  if ((times[0].tv_sec &

       (1ULL << (sizeof(times[0].tv_sec) * CHAR_BIT - 1))) != 0)

  {

    return ISC_R_RANGE;

  }

  /*

   * isc_time_nanoseconds guarantees a value that divided by 1000 will

   * fit into the minimum possible size tv_usec field.

   */

  times[0].tv_usec = times[1].tv_usec =

    (int32_t)(isc_time_nanoseconds(when) / 1000);

  if (utimes(file, times) < 0) {

    return isc__errno2result(errno);

  }

  return ISC_R_SUCCESS;

}

#undef TEMPLATE

#define TEMPLATE "tmp-XXXXXXXXXX" /*%< 14 characters. */

isc_result_t

isc_file_mktemplate(const char *path, char *buf, size_t buflen) {

  return isc_file_template(path, TEMPLATE, buf, buflen);

}

isc_result_t

isc_file_template(const char *path, const char *templet, char *buf,

      size_t buflen) {

  const char *s;

  REQUIRE(templet != NULL);

  REQUIRE(buf != NULL);

  if (path == NULL) {

    path = "";

  }

  s = strrchr(templet, '/');

  if (s != NULL) {

    templet = s + 1;

  }

  s = strrchr(path, '/');

  if (s != NULL) {

    size_t prefixlen = s - path + 1;

    if ((prefixlen + strlen(templet) + 1) > buflen) {

      return ISC_R_NOSPACE;

    }

    /* Copy 'prefixlen' bytes and NUL terminate. */

    strlcpy(buf, path, ISC_MIN(prefixlen + 1, buflen));

    strlcat(buf, templet, buflen);

  } else {

    if ((strlen(templet) + 1) > buflen) {

      return ISC_R_NOSPACE;

    }

    strlcpy(buf, templet, buflen);

  }

  return ISC_R_SUCCESS;

}

static const char alphnum[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuv"

            "wxyz0123456789";

isc_result_t

isc_file_renameunique(const char *file, char *templet) {

  char *x;

  char *cp;

  REQUIRE(file != NULL);

  REQUIRE(templet != NULL);

  cp = templet;

  while (*cp != '\0') {

    cp++;

  }

  if (cp == templet) {

    return ISC_R_FAILURE;

  }

  x = cp--;

  while (cp >= templet && *cp == 'X') {

    *cp = alphnum[isc_random_uniform(sizeof(alphnum) - 1)];

    x = cp--;

  }

  while (link(file, templet) == -1) {

    if (errno != EEXIST) {

      return isc__errno2result(errno);

    }

    for (cp = x;;) {

      const char *t;

      if (*cp == '\0') {

        return ISC_R_FAILURE;

      }

      t = strchr(alphnum, *cp);

      if (t == NULL || *++t == '\0') {

        *cp++ = alphnum[0];

      } else {

        *cp = *t;

        break;

      }

    }

  }

  if (unlink(file) < 0) {

    if (errno != ENOENT) {

      return isc__errno2result(errno);

    }

  }

  return ISC_R_SUCCESS;

}

isc_result_t

isc_file_openunique(char *templet, FILE **fp) {

  int mode = S_IWUSR | S_IRUSR | S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH;

  return isc_file_openuniquemode(templet, mode, fp);

}

isc_result_t

isc_file_openuniqueprivate(char *templet, FILE **fp) {

  int mode = S_IWUSR | S_IRUSR;

  return isc_file_openuniquemode(templet, mode, fp);

}

isc_result_t

isc_file_openuniquemode(char *templet, int mode, FILE **fp) {

  int fd;

  FILE *f;

  isc_result_t result = ISC_R_SUCCESS;

  char *x;

  char *cp;

  REQUIRE(templet != NULL);

  REQUIRE(fp != NULL && *fp == NULL);

  cp = templet;

  while (*cp != '\0') {

    cp++;

  }

  if (cp == templet) {

    return ISC_R_FAILURE;

  }

  x = cp--;

  while (cp >= templet && *cp == 'X') {

    *cp = alphnum[isc_random_uniform(sizeof(alphnum) - 1)];

    x = cp--;

  }

  while ((fd = open(templet, O_RDWR | O_CREAT | O_EXCL, mode)) == -1) {

    if (errno != EEXIST) {

      return isc__errno2result(errno);

    }

    for (cp = x;;) {

      char *t;

      if (*cp == '\0') {

        return ISC_R_FAILURE;

      }

      t = strchr(alphnum, *cp);

      if (t == NULL || *++t == '\0') {

        *cp++ = alphnum[0];

      } else {

        *cp = *t;

        break;

      }

    }

  }

  f = fdopen(fd, "w+");

  if (f == NULL) {

    result = isc__errno2result(errno);

    if (remove(templet) < 0) {

      isc_log_write(ISC_LOGCATEGORY_GENERAL,

              ISC_LOGMODULE_FILE, ISC_LOG_ERROR,

              "remove '%s': failed", templet);

    }

    (void)close(fd);

  } else {

    *fp = f;

  }

  return result;

}

isc_result_t

isc_file_remove(const char *filename) {

  int r;

  REQUIRE(filename != NULL);

  r = unlink(filename);

  if (r == 0) {

    return ISC_R_SUCCESS;

  } else {

    return isc__errno2result(errno);

  }

}

isc_result_t

isc_file_rename(const char *oldname, const char *newname) {

  int r;

  REQUIRE(oldname != NULL);

  REQUIRE(newname != NULL);

  r = rename(oldname, newname);

  if (r == 0) {

    return ISC_R_SUCCESS;

  } else {

    return isc__errno2result(errno);

  }

}

bool

isc_file_exists(const char *pathname) {

  struct stat stats;

  REQUIRE(pathname != NULL);

  return file_stats(pathname, &stats) == ISC_R_SUCCESS;

}

isc_result_t

isc_file_isplainfile(const char *filename) {

  /*

   * This function returns success if filename is a plain file.

   */

  struct stat filestat;

  memset(&filestat, 0, sizeof(struct stat));

  if ((stat(filename, &filestat)) == -1) {

    return isc__errno2result(errno);

  }

  if (!S_ISREG(filestat.st_mode)) {

    return ISC_R_INVALIDFILE;

  }

  return ISC_R_SUCCESS;

}

isc_result_t

isc_file_isplainfilefd(int fd) {

  /*

   * This function returns success if filename is a plain file.

   */

  struct stat filestat;

  memset(&filestat, 0, sizeof(struct stat));

  if ((fstat(fd, &filestat)) == -1) {

    return isc__errno2result(errno);

  }

  if (!S_ISREG(filestat.st_mode)) {

    return ISC_R_INVALIDFILE;

  }

  return ISC_R_SUCCESS;

}

isc_result_t

isc_file_isdirectory(const char *filename) {

  /*

   * This function returns success if filename exists and is a

   * directory.

   */

  struct stat filestat;

  memset(&filestat, 0, sizeof(struct stat));

  if ((stat(filename, &filestat)) == -1) {

    return isc__errno2result(errno);

  }

  if (!S_ISDIR(filestat.st_mode)) {

    return ISC_R_INVALIDFILE;

  }

  return ISC_R_SUCCESS;

}

bool

isc_file_isabsolute(const char *filename) {

  REQUIRE(filename != NULL);

  return filename[0] == '/';

}

bool

isc_file_iscurrentdir(const char *filename) {

  REQUIRE(filename != NULL);

  return filename[0] == '.' && filename[1] == '\0';

}

bool

isc_file_ischdiridempotent(const char *filename) {

  REQUIRE(filename != NULL);

  if (isc_file_isabsolute(filename)) {

    return true;

  }

  if (isc_file_iscurrentdir(filename)) {

    return true;

  }

  return false;

}

const char *

isc_file_basename(const char *filename) {

  const char *s;

  REQUIRE(filename != NULL);

  s = strrchr(filename, '/');

  if (s == NULL) {

    return filename;

  }

  return s + 1;

}

void

isc_file_progname(const char *filename, char *buf, size_t buflen) {

  const char *base;

  size_t len;

  REQUIRE(filename != NULL);

  REQUIRE(buf != NULL);

  base = isc_file_basename(filename);

  /*

   * Libtool doesn't preserve the program name prior to final

   * installation.  Remove the libtool prefix ("lt-").

   */

  if (strncmp(base, "lt-", 3) == 0) {

    base += 3;

  }

  len = strlen(base) + 1;

  RUNTIME_CHECK(len <= buflen);

  memmove(buf, base, len);

}

/*

 * Put the absolute name of the current directory into 'dirname', which is

 * a buffer of at least 'length' characters.  End the string with the

 * appropriate path separator, such that the final product could be

 * concatenated with a relative pathname to make a valid pathname string.

 */

static isc_result_t

dir_current(char *dirname, size_t length) {

  char *cwd;

  isc_result_t result = ISC_R_SUCCESS;

  REQUIRE(dirname != NULL);

  REQUIRE(length > 0U);

  cwd = getcwd(dirname, length);

  if (cwd == NULL) {

    if (errno == ERANGE) {

      result = ISC_R_NOSPACE;

    } else {

      result = isc__errno2result(errno);

    }

  } else {

    if (strlen(dirname) + 1 == length) {

      result = ISC_R_NOSPACE;

    } else if (dirname[1] != '\0') {

      strlcat(dirname, "/", length);

    }

  }

  return result;

}

isc_result_t

isc_file_absolutepath(const char *filename, char *path, size_t pathlen) {

  isc_result_t result;

  result = dir_current(path, pathlen);

  if (result != ISC_R_SUCCESS) {

    return result;

  }

  if (strlen(path) + strlen(filename) + 1 > pathlen) {

    return ISC_R_NOSPACE;

  }

  strlcat(path, filename, pathlen);

  return ISC_R_SUCCESS;

}

isc_result_t

isc_file_truncate(const char *filename, off_t size) {

  isc_result_t result = ISC_R_SUCCESS;

  if (truncate(filename, size) < 0) {

    result = isc__errno2result(errno);

  }

  return result;

}

isc_result_t

isc_file_safecreate(const char *filename, FILE **fp) {

  isc_result_t result;

  int flags;

  struct stat sb;

  FILE *f;

  int fd;

  REQUIRE(filename != NULL);

  REQUIRE(fp != NULL && *fp == NULL);

  result = file_stats(filename, &sb);

  if (result == ISC_R_SUCCESS) {

    if ((sb.st_mode & S_IFREG) == 0) {

      return ISC_R_INVALIDFILE;

    }

    flags = O_WRONLY | O_TRUNC;

  } else if (result == ISC_R_FILENOTFOUND) {

    flags = O_WRONLY | O_CREAT | O_EXCL;

  } else {

    return result;

  }

  fd = open(filename, flags, S_IRUSR | S_IWUSR);

  if (fd == -1) {

    return isc__errno2result(errno);

  }

  f = fdopen(fd, "w");

  if (f == NULL) {

    result = isc__errno2result(errno);

    close(fd);

    return result;

  }

  *fp = f;

  return ISC_R_SUCCESS;

}

isc_result_t

isc_file_splitpath(isc_mem_t *mctx, const char *path, char **dirname,

       char const **bname) {

  char *dir = NULL;

  const char *file = NULL, *slash = NULL;

  if (path == NULL) {

    return ISC_R_INVALIDFILE;

  }

  slash = strrchr(path, '/');

  if (slash == path) {

    file = ++slash;

    dir = isc_mem_strdup(mctx, "/");

  } else if (slash != NULL) {

    file = ++slash;

    dir = isc_mem_allocate(mctx, slash - path);

    strlcpy(dir, path, slash - path);

  } else {

    file = path;

    dir = isc_mem_strdup(mctx, ".");

  }

  if (*file == '\0') {

    isc_mem_free(mctx, dir);

    return ISC_R_INVALIDFILE;

  }

  *dirname = dir;

  *bname = file;

  return ISC_R_SUCCESS;

}

#define DISALLOW "\\/ABCDEFGHIJKLMNOPQRSTUVWXYZ"

static isc_result_t

digest2hex(unsigned char *digest, unsigned int digestlen, char *hash,

     size_t hashlen) {

  unsigned int i;

  int ret;

  for (i = 0; i < digestlen; i++) {

    size_t left = hashlen - i * 2;

    ret = snprintf(hash + i * 2, left, "%02x", digest[i]);

    if (ret < 0 || (size_t)ret >= left) {

      return ISC_R_NOSPACE;

    }

  }

  return ISC_R_SUCCESS;

}

isc_result_t

isc_file_sanitize(const char *dir, const char *base, const char *ext,

      char *path, size_t length) {

  char buf[PATH_MAX];

  unsigned char digest[ISC_MAX_MD_SIZE];

  unsigned int digestlen;

  char hash[ISC_MAX_MD_SIZE * 2 + 1];

  size_t l = 0;

  isc_result_t err;

  REQUIRE(base != NULL);

  REQUIRE(path != NULL);

  l = strlen(base) + 1;

  /*

   * allow room for a full sha256 hash (64 chars

   * plus null terminator)

   */

  if (l < 65U) {

    l = 65;

  }

  if (dir != NULL) {

    l += strlen(dir) + 1;

  }

  if (ext != NULL) {

    l += strlen(ext) + 1;

  }

  if (l > length || l > (unsigned int)PATH_MAX) {

    return ISC_R_NOSPACE;

  }

  /* Check whether the full-length SHA256 hash filename exists */

  err = isc_md(ISC_MD_SHA256, (const unsigned char *)base, strlen(base),

         digest, &digestlen);

  if (err != ISC_R_SUCCESS) {

    return err;

  }

  err = digest2hex(digest, digestlen, hash, sizeof(hash));

  if (err != ISC_R_SUCCESS) {

    return err;

  }

  snprintf(buf, sizeof(buf), "%s%s%s%s%s", dir != NULL ? dir : "",

     dir != NULL ? "/" : "", hash, ext != NULL ? "." : "",

     ext != NULL ? ext : "");

  if (isc_file_exists(buf)) {

    strlcpy(path, buf, length);

    return ISC_R_SUCCESS;

  }

  /* Check for a truncated SHA256 hash filename */

  hash[16] = '\0';

  snprintf(buf, sizeof(buf), "%s%s%s%s%s", dir != NULL ? dir : "",

     dir != NULL ? "/" : "", hash, ext != NULL ? "." : "",

     ext != NULL ? ext : "");

  if (isc_file_exists(buf)) {

    strlcpy(path, buf, length);

    return ISC_R_SUCCESS;

  }

  /*

   * If neither hash filename already exists, then we'll use

   * the original base name if it has no disallowed characters,

   * or the truncated hash name if it does.

   */

  if (strpbrk(base, DISALLOW) != NULL) {

    strlcpy(path, buf, length);

    return ISC_R_SUCCESS;

  }

  snprintf(buf, sizeof(buf), "%s%s%s%s%s", dir != NULL ? dir : "",

     dir != NULL ? "/" : "", base, ext != NULL ? "." : "",

     ext != NULL ? ext : "");

  strlcpy(path, buf, length);

  return ISC_R_SUCCESS;

}

bool

isc_file_isdirwritable(const char *path) {

  return access(path, W_OK | X_OK) == 0;

}