//
// Temp file utilities for CUPS.
//
// Copyright © 2021-2023 by OpenPrinting.
// Copyright © 2007-2018 by Apple Inc.
// Copyright © 1997-2006 by Easy Software Products.
//
// Licensed under Apache License v2.0.  See the file "LICENSE" for more
// information.
//

#include "cups-private.h"
#include <stdlib.h>
#include <fcntl.h>
#include <sys/stat.h>
#if defined(_WIN32) || defined(__EMX__)
#  include <io.h>
#else
#  include <unistd.h>
#endif // _WIN32 || __EMX__


//
// 'cupsCreateTempFd()' - Creates a temporary file.
//
// This function creates a temporary file and returns a file descriptor for the
// file.  The unique temporary filename uses the "prefix" and "suffix" arguments
// and is returned in the filename buffer.  The temporary file is opened for
// reading and writing.
//

int					// O - New file descriptor or `-1` on error
cupsCreateTempFd(const char *prefix,	// I - Filename prefix or `NULL` for none
                 const char *suffix, 	// I - Filename suffix or `NULL` for none
                 char       *filename,	// I - Pointer to buffer
                 size_t     len)	// I - Size of buffer
{
  int		fd;			// File descriptor for temp file
  int		tries;			// Number of tries
  const char	*tmpdir;		// TMPDIR environment var
#if (defined(__APPLE__) && defined(_CS_DARWIN_USER_TEMP_DIR)) || defined(_WIN32)
  char		tmppath[1024];		// Temporary directory
#endif // (__APPLE__ && _CS_DARWIN_USER_TEMP_DIR) || _WIN32
#ifdef _WIN32
  DWORD		curtime;		// Current time
#else
  struct timeval curtime;		// Current time
#endif // _WIN32


  // Get the current temporary directory...
#ifdef _WIN32
  if ((tmpdir = getenv("TEMP")) == NULL)
  {
    // Use the Windows API to get the system temporary directory...
    GetTempPathA(sizeof(tmppath), tmppath);
    tmpdir = tmppath;
  }

#elif defined(__APPLE__)
  // On macOS and iOS, the TMPDIR environment variable is not always the best
  // location to place temporary files due to sandboxing.  Instead, the confstr
  // function should be called to get the proper per-user, per-process TMPDIR
  // value.
  if ((tmpdir = getenv("TMPDIR")) != NULL && access(tmpdir, W_OK))
    tmpdir = NULL;

  if (!tmpdir)
  {
#ifdef _CS_DARWIN_USER_TEMP_DIR
    if (confstr(_CS_DARWIN_USER_TEMP_DIR, tmppath, sizeof(tmppath)))
      tmpdir = tmppath;
    else
#endif // _CS_DARWIN_USER_TEMP_DIR
      tmpdir = "/private/tmp";		// macOS 10.4 and earlier
  }

#else
  // Previously we put root temporary files in the default CUPS temporary
  // directory under /var/spool/cups.  However, since the scheduler cleans
  // out temporary files there and runs independently of the user apps, we
  // don't want to use it unless specifically told to by cupsd.
  if ((tmpdir = getenv("TMPDIR")) == NULL)
    tmpdir = "/tmp";
#endif // _WIN32

  // Make the temporary name using the specified directory...
  tries = 0;

  do
  {
#ifdef _WIN32
    // Get the current time of day...
    curtime =  GetTickCount() + tries;

    // Format a string using the hex time values...
    snprintf(filename, (size_t)len - 1, "%s/%s%05lx%08lx%s", tmpdir, prefix ? prefix : "", GetCurrentProcessId(), curtime, suffix ? suffix : "");

#else
    // Get the current time of day...
    gettimeofday(&curtime, NULL);

    // Format a string using the hex time values...
    snprintf(filename, (size_t)len - 1, "%s/%s%05x%08x%s", tmpdir, prefix ? prefix : "", (unsigned)getpid(), (unsigned)(curtime.tv_sec + curtime.tv_usec + tries), suffix ? suffix : "");
#endif // _WIN32

    // Open the file in "exclusive" mode, making sure that we don't
    // stomp on an existing file or someone's symlink crack...
#ifdef _WIN32
    fd = open(filename, _O_CREAT | _O_RDWR | _O_TRUNC | _O_BINARY, _S_IREAD | _S_IWRITE);
#elif defined(O_NOFOLLOW)
    fd = open(filename, O_RDWR | O_CREAT | O_EXCL | O_NOFOLLOW, 0600);
#else
    fd = open(filename, O_RDWR | O_CREAT | O_EXCL, 0600);
#endif // _WIN32

    if (fd < 0 && errno != EEXIST)
      break;

    tries ++;
  }
  while (fd < 0 && tries < 1000);

  // Clear the filename if we didn't create a file...
  if (fd < 0)
    *filename = '\0';

  // Return the file descriptor...
  return (fd);
}


//
// 'cupsCreateTempFile()' - Creates a temporary CUPS file.
//
// This function creates a temporary file and returns a file descriptor for the
// file.  The unique temporary filename uses the "prefix" and "suffix" arguments
// and is returned in the filename buffer.  The temporary file is opened for
// writing.
//

cups_file_t *				// O - CUPS file or `NULL` on error
cupsCreateTempFile(const char *prefix,	// I - Filename prefix or `NULL` for none
                   const char *suffix, 	// I - Filename suffix or `NULL` for none
		   char       *filename,// I - Pointer to buffer
		   size_t     len)	// I - Size of buffer
{
  cups_file_t	*file;			// CUPS file
  int		fd;			// File descriptor


  if ((fd = cupsCreateTempFd(prefix, suffix, filename, len)) < 0)
  {
    return (NULL);
  }
  else if ((file = cupsFileOpenFd(fd, "w")) == NULL)
  {
    close(fd);
    unlink(filename);
    return (NULL);
  }
  else
  {
    return (file);
  }
}
