/* tempfile.c

 * Routines to create temporary files

 *

 * Wireshark - Network traffic analyzer

 * By Gerald Combs <gerald@wireshark.org>

 * Copyright 1998 Gerald Combs

 *

 * SPDX-License-Identifier: GPL-2.0-or-later

 */

#include "config.h"

#include "tempfile.h"

#include <errno.h>

#include "file_util.h"

static char *

sanitize_prefix(const char *prefix)

{

  if (!prefix) {

      return NULL;

  }

  /* The characters in "delimiters" come from:

   * https://docs.microsoft.com/en-us/windows/win32/fileio/naming-a-file#naming-conventions.

   * Add to the list as necessary for other OS's.

   */

  const char *delimiters = "<>:\"/\\|?*"

    "\x01\x02\x03\x04\x05\x06\x07\x08\x09\x0a"

    "\x0b\x0c\x0d\x0e\x0f\x10\x11\x12\x13\x14"

    "\x15\x16\x17\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f";

  /* Sanitize the prefix to resolve bug 7877 */

  char *safe_prefx = g_strdup(prefix);

  safe_prefx = g_strdelimit(safe_prefx, delimiters, '-');

  return safe_prefx;

}

 /**

 * Create a tempfile with the given prefix (e.g. "wireshark"). The path

 * is created using g_file_open_tmp.

 *

 * @param tempdir [in] If not NULL, the directory in which to create the file.

 * @param namebuf [in,out] If not NULL, receives the full path of the temp file.

 *                Must be freed.

 * @param pfx [in] A prefix for the temporary file.

 * @param sfx [in] A file extension for the temporary file. NULL can be passed

 *                 if no file extension is needed

 * @param err [out] Any error returned by g_file_open_tmp. May be NULL

 * @return The file descriptor of the new tempfile, from mkstemps().

 */

int

create_tempfile(const char *tempdir, char **namebuf, const char *pfx, const char *sfx, GError **err)

{

  int fd;

  char *safe_pfx = sanitize_prefix(pfx);

  if (tempdir == NULL || tempdir[0] == '\0') {

    /* Use OS default tempdir behaviour */

    char* filetmpl = ws_strdup_printf("%sXXXXXX%s", safe_pfx ? safe_pfx : "", sfx ? sfx : "");

    g_free(safe_pfx);

    fd = g_file_open_tmp(filetmpl, namebuf, err);

    g_free(filetmpl);

  }

  else {

    /* User-specified tempdir.

     * We don't get libc's help generating a random name here.

     */

    const char alphabet[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789_-";

    const int32_t a_len = 64;

    char* filetmpl = NULL;

    while(1) {

      g_free(filetmpl);

      filetmpl = ws_strdup_printf("%s%c%s%c%c%c%c%c%c%s",

          tempdir,

          G_DIR_SEPARATOR,

          safe_pfx ? safe_pfx : "",

          alphabet[g_random_int_range(0, a_len)],

          alphabet[g_random_int_range(0, a_len)],

          alphabet[g_random_int_range(0, a_len)],

          alphabet[g_random_int_range(0, a_len)],

          alphabet[g_random_int_range(0, a_len)],

          alphabet[g_random_int_range(0, a_len)],

          sfx ? sfx : "");

      fd = ws_open(filetmpl, O_CREAT|O_EXCL|O_BINARY|O_WRONLY, 0600);

      if (fd >= 0) {

        break;

      }

      if (errno != EEXIST) {

        g_set_error_literal(err, G_FILE_ERROR,

            g_file_error_from_errno(errno), g_strerror(errno));

        g_free(filetmpl);

        filetmpl = NULL;

        break;

      }

      /* Loop continues if error was EEXIST, meaning the file we tried

       * to make already existed at the destination

       */

    }

    if (namebuf == NULL) {

      g_free(filetmpl);

    }

    else {

      *namebuf = filetmpl;

    }

    g_free(safe_pfx);

  }

  return fd;

}

char *

create_tempdir(const char *parent_dir, const char *tmpl, GError **err)

{

  if (parent_dir == NULL || parent_dir[0] == '\0') {

      parent_dir = g_get_tmp_dir();

  }

  char *safe_pfx = sanitize_prefix(tmpl);

  if (safe_pfx == NULL) {

    safe_pfx = g_strdup("wireshark_XXXXXX");

  }

  char *temp_subdir = g_build_path(G_DIR_SEPARATOR_S, parent_dir, safe_pfx, NULL);

  g_free(safe_pfx);

  if (g_mkdtemp(temp_subdir) == NULL)

  {

      g_free(temp_subdir);

      g_set_error_literal(err, G_FILE_ERROR,

          g_file_error_from_errno(errno), g_strerror(errno));

      return NULL;

  }

  return temp_subdir;

}

/*

 * Editor modelines  -  https://www.wireshark.org/tools/modelines.html

 *

 * Local Variables:

 * c-basic-offset: 2

 * tab-width: 8

 * indent-tabs-mode: nil

 * End:

 *

 * ex: set shiftwidth=2 tabstop=8 expandtab:

 * :indentSize=2:tabSize=8:noTabs=true:

 */