/***************************************************************************

 *                                  _   _ ____  _

 *  Project                     ___| | | |  _ \| |

 *                             / __| | | | |_) | |

 *                            | (__| |_| |  _ <| |___

 *                             \___|\___/|_| \_\_____|

 *

 * Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.

 *

 * This software is licensed as described in the file COPYING, which

 * you should have received as part of this distribution. The terms

 * are also available at https://curl.se/docs/copyright.html.

 *

 * You may opt to use, copy, modify, merge, publish, distribute and/or sell

 * copies of the Software, and permit persons to whom the Software is

 * furnished to do so, under the terms of the COPYING file.

 *

 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY

 * KIND, either express or implied.

 *

 * SPDX-License-Identifier: curl

 *

 ***************************************************************************/

#include "curl_setup.h"

#if !defined(CURL_DISABLE_COOKIES) || !defined(CURL_DISABLE_ALTSVC) || \

  !defined(CURL_DISABLE_HSTS)

#include "urldata.h"

#include "rand.h"

#include "curl_fopen.h"

/* The dirslash() function breaks a null-terminated pathname string into

   directory and filename components then returns the directory component up

   to, *AND INCLUDING*, a final '/'. If there is no directory in the path,

   this instead returns a "" string.

   This function returns a pointer to malloc'ed memory.

   The input path to this function is expected to have a filename part.

 */

#ifdef _WIN32

#define PATHSEP   "\\"

#define IS_SEP(x) (((x) == '/') || ((x) == '\\'))

#elif defined(MSDOS) || defined(OS2)

#define PATHSEP   "\\"

#define IS_SEP(x) ((x) == '\\')

#else

#define PATHSEP   "/"

#define IS_SEP(x) ((x) == '/')

#endif

static char *dirslash(const char *path)

{

  size_t n;

  struct dynbuf out;

  DEBUGASSERT(path);

  curlx_dyn_init(&out, CURL_MAX_INPUT_LENGTH);

  n = strlen(path);

  if(n) {

    /* find the rightmost path separator, if any */

    while(n && !IS_SEP(path[n - 1]))

      --n;

    /* skip over all the path separators, if any */

    while(n && IS_SEP(path[n - 1]))

      --n;

  }

  if(curlx_dyn_addn(&out, path, n))

    return NULL;

  /* if there was a directory, append a single trailing slash */

  if(n && curlx_dyn_addn(&out, PATHSEP, 1))

    return NULL;

  return curlx_dyn_ptr(&out);

}

/*

 * Curl_fopen() opens a file for writing with a temp name, to be renamed

 * to the final name when completed. If there is an existing file using this

 * name at the time of the open, this function will clone the mode from that

 * file. if 'tempname' is non-NULL, it needs a rename after the file is

 * written.

 */

CURLcode Curl_fopen(struct Curl_easy *data, const char *filename,

                    FILE **fh, char **tempname)

{

  CURLcode result = CURLE_WRITE_ERROR;

  unsigned char randbuf[41];

  char *tempstore = NULL;

#ifndef _WIN32

  curlx_struct_stat sb;

#endif

  int fd = -1;

  char *dir = NULL;

  *tempname = NULL;

#ifndef _WIN32

  *fh = curlx_fopen(filename, FOPEN_WRITETEXT);

  if(!*fh)

    goto fail;

  if(curlx_fstat(fileno(*fh), &sb) == -1 || !S_ISREG(sb.st_mode)) {

    return CURLE_OK;

  }

  curlx_fclose(*fh);

#ifdef HAVE_GETEUID

  /* If the existing file is not owned by the user, do not inherit

   * its permissions at the temp file created below. The permissions

   * might be unsuitable for holding user private data. */

  if(sb.st_uid != geteuid())

    sb.st_mode = 0;

#endif

#endif /* !_WIN32 */

  *fh = NULL;

  result = Curl_rand_alnum(data, randbuf, sizeof(randbuf));

  if(result)

    goto fail;

  dir = dirslash(filename);

  if(dir) {

    /* The temp filename should not end up too long for the target file

       system */

    tempstore = curl_maprintf("%s%s.tmp", dir, randbuf);

    curlx_free(dir);

  }

  if(!tempstore) {

    result = CURLE_OUT_OF_MEMORY;

    goto fail;

  }

  result = CURLE_WRITE_ERROR;

#ifdef _WIN32

  fd = curlx_open(tempstore, _O_WRONLY | _O_CREAT | _O_EXCL,

                  _S_IREAD | _S_IWRITE);

#elif (defined(ANDROID) || defined(__ANDROID__)) && \

  (defined(__i386__) || defined(__arm__))

  fd = curlx_open(tempstore, O_WRONLY | O_CREAT | O_EXCL,

                  (mode_t)(S_IRUSR | S_IWUSR | sb.st_mode));

#else

  fd = curlx_open(tempstore, O_WRONLY | O_CREAT | O_EXCL,

                  S_IRUSR | S_IWUSR | sb.st_mode);

#endif

  if(fd == -1)

    goto fail;

  *fh = curlx_fdopen(fd, FOPEN_WRITETEXT);

  if(!*fh)

    goto fail;

  *tempname = tempstore;

  return CURLE_OK;

fail:

  if(fd != -1) {

    curlx_close(fd);

    unlink(tempstore);

  }

  curlx_free(tempstore);

  return result;

}

#endif /* !disabled */