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  * Licensed under Apache License v2.0.  See the file "LICENSE" for more
   8  * information.
   9  */
  10
  11 /*
  12  * Include necessary headers...
  13  */
  14
  15 #include "cups-private.h"
  16 #include <stdlib.h>
  17 #include <fcntl.h>
  18 #include <sys/stat.h>
  19 #if defined(_WIN32) || defined(__EMX__)
  20 #  include <io.h>
  21 #else
  22 #  include <unistd.h>
  23 #endif /* _WIN32 || __EMX__ */
  24
  25
  26 /*
  27  * 'cupsTempFd()' - Creates a temporary file.
  28  *
  29  * The temporary filename is returned in the filename buffer.
  30  * The temporary file is opened for reading and writing.
  31  */
  32
  33 int                                     /* O - New file descriptor or -1 on error */
  34 cupsTempFd(char *filename,              /* I - Pointer to buffer */
  35            int  len)                    /* I - Size of buffer */
  36 {
  37   int           fd;                     /* File descriptor for temp file */
  38   int           tries;                  /* Number of tries */
  39   const char    *tmpdir;                /* TMPDIR environment var */
  40 #if defined(__APPLE__) || defined(_WIN32)
  41   char          tmppath[1024];          /* Temporary directory */
  42 #endif /* __APPLE__ || _WIN32 */
  43 #ifdef _WIN32
  44   DWORD         curtime;                /* Current time */
  45 #else
  46   struct timeval curtime;               /* Current time */
  47 #endif /* _WIN32 */
  48
  49
  50  /*
  51   * See if TMPDIR is defined...
  52   */
  53
  54 #ifdef _WIN32
  55   if ((tmpdir = getenv("TEMP")) == NULL)
  56   {
  57     GetTempPath(sizeof(tmppath), tmppath);
  58     tmpdir = tmppath;
  59   }
  60
  61 #elif defined(__APPLE__)
  62  /*
  63   * On macOS and iOS, the TMPDIR environment variable is not always the best
  64   * location to place temporary files due to sandboxing.  Instead, the confstr
  65   * function should be called to get the proper per-user, per-process TMPDIR
  66   * value.
  67   */
  68
  69   if ((tmpdir = getenv("TMPDIR")) != NULL && access(tmpdir, W_OK))
  70     tmpdir = NULL;
  71
  72   if (!tmpdir)
  73   {
  74     if (confstr(_CS_DARWIN_USER_TEMP_DIR, tmppath, sizeof(tmppath)))
  75       tmpdir = tmppath;
  76     else
  77       tmpdir = "/private/tmp";          /* This should never happen */
  78   }
  79
  80 #else
  81  /*
  82   * Previously we put root temporary files in the default CUPS temporary
  83   * directory under /var/spool/cups.  However, since the scheduler cleans
  84   * out temporary files there and runs independently of the user apps, we
  85   * don't want to use it unless specifically told to by cupsd.
  86   */
  87
  88   if ((tmpdir = getenv("TMPDIR")) == NULL)
  89     tmpdir = "/tmp";
  90 #endif /* _WIN32 */
  91
  92  /*
  93   * Make the temporary name using the specified directory...
  94   */
  95
  96   tries = 0;
  97
  98   do
  99   {
 100 #ifdef _WIN32
 101    /*
 102     * Get the current time of day...
 103     */
 104
 105     curtime =  GetTickCount() + tries;
 106
 107    /*
 108     * Format a string using the hex time values...
 109     */
 110
 111     snprintf(filename, (size_t)len - 1, "%s/%05lx%08lx", tmpdir, GetCurrentProcessId(), curtime);
 112 #else
 113    /*
 114     * Get the current time of day...
 115     */
 116
 117     gettimeofday(&curtime, NULL);
 118
 119    /*
 120     * Format a string using the hex time values...
 121     */
 122
 123     snprintf(filename, (size_t)len - 1, "%s/%05x%08x", tmpdir, (unsigned)getpid(), (unsigned)(curtime.tv_sec + curtime.tv_usec + tries));
 124 #endif /* _WIN32 */
 125
 126    /*
 127     * Open the file in "exclusive" mode, making sure that we don't
 128     * stomp on an existing file or someone's symlink crack...
 129     */
 130
 131 #ifdef _WIN32
 132     fd = open(filename, _O_CREAT | _O_RDWR | _O_TRUNC | _O_BINARY,
 133               _S_IREAD | _S_IWRITE);
 134 #elif defined(O_NOFOLLOW)
 135     fd = open(filename, O_RDWR | O_CREAT | O_EXCL | O_NOFOLLOW, 0600);
 136 #else
 137     fd = open(filename, O_RDWR | O_CREAT | O_EXCL, 0600);
 138 #endif /* _WIN32 */
 139
 140     if (fd < 0 && errno != EEXIST)
 141       break;
 142
 143     tries ++;
 144   }
 145   while (fd < 0 && tries < 1000);
 146
 147  /*
 148   * Return the file descriptor...
 149   */
 150
 151   return (fd);
 152 }
 153
 154
 155 /*
 156  * 'cupsTempFile()' - Generates a temporary filename.
 157  *
 158  * The temporary filename is returned in the filename buffer.
 159  * This function is deprecated and will no longer generate a temporary
 160  * filename - use @link cupsTempFd@ or @link cupsTempFile2@ instead.
 161  *
 162  * @deprecated@
 163  */
 164
 165 char *                                  /* O - Filename or @code NULL@ on error */
 166 cupsTempFile(char *filename,            /* I - Pointer to buffer */
 167              int  len)                  /* I - Size of buffer */
 168 {
 169   (void)len;
 170
 171   if (filename)
 172     *filename = '\0';
 173
 174   return (NULL);
 175 }
 176
 177
 178 /*
 179  * 'cupsTempFile2()' - Creates a temporary CUPS file.
 180  *
 181  * The temporary filename is returned in the filename buffer.
 182  * The temporary file is opened for writing.
 183  *
 184  * @since CUPS 1.2/macOS 10.5@
 185  */
 186
 187 cups_file_t *                           /* O - CUPS file or @code NULL@ on error */
 188 cupsTempFile2(char *filename,           /* I - Pointer to buffer */
 189               int  len)                 /* I - Size of buffer */
 190 {
 191   cups_file_t   *file;                  /* CUPS file */
 192   int           fd;                     /* File descriptor */
 193
 194
 195   if ((fd = cupsTempFd(filename, len)) < 0)
 196     return (NULL);
 197   else if ((file = cupsFileOpenFd(fd, "w")) == NULL)
 198   {
 199     close(fd);
 200     unlink(filename);
 201     return (NULL);
 202   }
 203   else
 204     return (file);
 205 }