cups/tempfile.c

   1 /*
   2  * Temp file utilities for CUPS.
   3  *
   4  * Copyright © 2007-2018 by Apple Inc.
   5  * Copyright © 1997-2006 by Easy Software Products.
   6  *
   7  * These coded instructions, statements, and computer programs are the
   8  * property of Apple Inc. and are protected by Federal copyright
   9  * law.  Distribution and use rights are outlined in the file "LICENSE.txt"
  10  * which should have been included with this file.  If this file is
  11  * missing or damaged, see the license at "http://www.cups.org/".
  12  *
  13  * This file is subject to the Apple OS-Developed Software exception.
  14  */
  15
  16 /*
  17  * Include necessary headers...
  18  */
  19
  20 #include "cups-private.h"
  21 #include <stdlib.h>
  22 #include <fcntl.h>
  23 #include <sys/stat.h>
  24 #if defined(WIN32) || defined(__EMX__)
  25 #  include <io.h>
  26 #else
  27 #  include <unistd.h>
  28 #endif /* WIN32 || __EMX__ */
  29
  30
  31 /*
  32  * 'cupsTempFd()' - Creates a temporary file.
  33  *
  34  * The temporary filename is returned in the filename buffer.
  35  * The temporary file is opened for reading and writing.
  36  */
  37
  38 int                                     /* O - New file descriptor or -1 on error */
  39 cupsTempFd(char *filename,              /* I - Pointer to buffer */
  40            int  len)                    /* I - Size of buffer */
  41 {
  42   int           fd;                     /* File descriptor for temp file */
  43   int           tries;                  /* Number of tries */
  44   const char    *tmpdir;                /* TMPDIR environment var */
  45 #if defined(__APPLE__) || defined(WIN32)
  46   char          tmppath[1024];          /* Temporary directory */
  47 #endif /* __APPLE__ || WIN32 */
  48 #ifdef WIN32
  49   DWORD         curtime;                /* Current time */
  50 #else
  51   struct timeval curtime;               /* Current time */
  52 #endif /* WIN32 */
  53
  54
  55  /*
  56   * See if TMPDIR is defined...
  57   */
  58
  59 #ifdef WIN32
  60   if ((tmpdir = getenv("TEMP")) == NULL)
  61   {
  62     GetTempPath(sizeof(tmppath), tmppath);
  63     tmpdir = tmppath;
  64   }
  65
  66 #elif defined(__APPLE__)
  67  /*
  68   * On macOS and iOS, the TMPDIR environment variable is not always the best
  69   * location to place temporary files due to sandboxing.  Instead, the confstr
  70   * function should be called to get the proper per-user, per-process TMPDIR
  71   * value.
  72   */
  73
  74   if ((tmpdir = getenv("TMPDIR")) != NULL && access(tmpdir, W_OK))
  75     tmpdir = NULL;
  76
  77   if (!tmpdir)
  78   {
  79     if (confstr(_CS_DARWIN_USER_TEMP_DIR, tmppath, sizeof(tmppath)))
  80       tmpdir = tmppath;
  81     else
  82       tmpdir = "/private/tmp";          /* This should never happen */
  83   }
  84
  85 #else
  86  /*
  87   * Previously we put root temporary files in the default CUPS temporary
  88   * directory under /var/spool/cups.  However, since the scheduler cleans
  89   * out temporary files there and runs independently of the user apps, we
  90   * don't want to use it unless specifically told to by cupsd.
  91   */
  92
  93   if ((tmpdir = getenv("TMPDIR")) == NULL)
  94     tmpdir = "/tmp";
  95 #endif /* WIN32 */
  96
  97  /*
  98   * Make the temporary name using the specified directory...
  99   */
 100
 101   tries = 0;
 102
 103   do
 104   {
 105 #ifdef WIN32
 106    /*
 107     * Get the current time of day...
 108     */
 109
 110     curtime =  GetTickCount() + tries;
 111
 112    /*
 113     * Format a string using the hex time values...
 114     */
 115
 116     snprintf(filename, (size_t)len - 1, "%s/%05lx%08lx", tmpdir, GetCurrentProcessId(), curtime);
 117 #else
 118    /*
 119     * Get the current time of day...
 120     */
 121
 122     gettimeofday(&curtime, NULL);
 123
 124    /*
 125     * Format a string using the hex time values...
 126     */
 127
 128     snprintf(filename, (size_t)len - 1, "%s/%05x%08x", tmpdir, (unsigned)getpid(), (unsigned)(curtime.tv_sec + curtime.tv_usec + tries));
 129 #endif /* WIN32 */
 130
 131    /*
 132     * Open the file in "exclusive" mode, making sure that we don't
 133     * stomp on an existing file or someone's symlink crack...
 134     */
 135
 136 #ifdef WIN32
 137     fd = open(filename, _O_CREAT | _O_RDWR | _O_TRUNC | _O_BINARY,
 138               _S_IREAD | _S_IWRITE);
 139 #elif defined(O_NOFOLLOW)
 140     fd = open(filename, O_RDWR | O_CREAT | O_EXCL | O_NOFOLLOW, 0600);
 141 #else
 142     fd = open(filename, O_RDWR | O_CREAT | O_EXCL, 0600);
 143 #endif /* WIN32 */
 144
 145     if (fd < 0 && errno != EEXIST)
 146       break;
 147
 148     tries ++;
 149   }
 150   while (fd < 0 && tries < 1000);
 151
 152  /*
 153   * Return the file descriptor...
 154   */
 155
 156   return (fd);
 157 }
 158
 159
 160 /*
 161  * 'cupsTempFile()' - Generates a temporary filename.
 162  *
 163  * The temporary filename is returned in the filename buffer.
 164  * This function is deprecated and will no longer generate a temporary
 165  * filename - use @link cupsTempFd@ or @link cupsTempFile2@ instead.
 166  *
 167  * @deprecated@
 168  */
 169
 170 char *                                  /* O - Filename or @code NULL@ on error */
 171 cupsTempFile(char *filename,            /* I - Pointer to buffer */
 172              int  len)                  /* I - Size of buffer */
 173 {
 174   (void)len;
 175
 176   if (filename)
 177     *filename = '\0';
 178
 179   return (NULL);
 180 }
 181
 182
 183 /*
 184  * 'cupsTempFile2()' - Creates a temporary CUPS file.
 185  *
 186  * The temporary filename is returned in the filename buffer.
 187  * The temporary file is opened for writing.
 188  *
 189  * @since CUPS 1.2/macOS 10.5@
 190  */
 191
 192 cups_file_t *                           /* O - CUPS file or @code NULL@ on error */
 193 cupsTempFile2(char *filename,           /* I - Pointer to buffer */
 194               int  len)                 /* I - Size of buffer */
 195 {
 196   cups_file_t   *file;                  /* CUPS file */
 197   int           fd;                     /* File descriptor */
 198
 199
 200   if ((fd = cupsTempFd(filename, len)) < 0)
 201     return (NULL);
 202   else if ((file = cupsFileOpenFd(fd, "w")) == NULL)
 203   {
 204     close(fd);
 205     unlink(filename);
 206     return (NULL);
 207   }
 208   else
 209     return (file);
 210 }