libiberty/make-temp-file.c

   1 /* Utility to pick a temporary filename prefix.
   2    Copyright (C) 1996-2023 Free Software Foundation, Inc.
   3
   4 This file is part of the libiberty library.
   5 Libiberty is free software; you can redistribute it and/or
   6 modify it under the terms of the GNU Library General Public
   7 License as published by the Free Software Foundation; either
   8 version 2 of the License, or (at your option) any later version.
   9
  10 Libiberty is distributed in the hope that it will be useful,
  11 but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13 Library General Public License for more details.
  14
  15 You should have received a copy of the GNU Library General Public
  16 License along with libiberty; see the file COPYING.LIB.  If not,
  17 write to the Free Software Foundation, Inc., 51 Franklin Street - Fifth Floor,
  18 Boston, MA 02110-1301, USA.  */
  19
  20 #ifdef HAVE_CONFIG_H
  21 #include "config.h"
  22 #endif
  23
  24 #include <stdio.h>      /* May get P_tmpdir.  */
  25 #include <sys/types.h>
  26 #include <errno.h>
  27 #ifdef HAVE_UNISTD_H
  28 #include <unistd.h>
  29 #endif
  30 #ifdef HAVE_STDLIB_H
  31 #include <stdlib.h>
  32 #endif
  33 #ifdef HAVE_STRING_H
  34 #include <string.h>
  35 #endif
  36 #ifdef HAVE_SYS_FILE_H
  37 #include <sys/file.h>   /* May get R_OK, etc. on some systems.  */
  38 #endif
  39 #if defined(_WIN32) && !defined(__CYGWIN__)
  40 #define WIN32_LEAN_AND_MEAN
  41 #include <windows.h>
  42 #endif
  43 #if HAVE_SYS_STAT_H
  44 #include <sys/stat.h>
  45 #endif
  46
  47
  48 #ifndef R_OK
  49 #define R_OK 4
  50 #define W_OK 2
  51 #define X_OK 1
  52 #endif
  53
  54 #include "libiberty.h"
  55 extern int mkstemps (char *, int);
  56
  57 /* '/' works just fine on MS-DOS based systems.  */
  58 #ifndef DIR_SEPARATOR
  59 #define DIR_SEPARATOR '/'
  60 #endif
  61
  62 /* Name of temporary file.
  63    mktemp requires 6 trailing X's.  */
  64 #define TEMP_FILE "XXXXXX"
  65 #define TEMP_FILE_LEN (sizeof(TEMP_FILE) - 1)
  66
  67 #if !defined(_WIN32) || defined(__CYGWIN__)
  68
  69 /* Subroutine of choose_tmpdir.
  70    If BASE is non-NULL, return it.
  71    Otherwise it checks if DIR is a usable directory.
  72    If success, DIR is returned.
  73    Otherwise NULL is returned.  */
  74
  75 static inline const char *try_dir (const char *, const char *);
  76
  77 static inline const char *
  78 try_dir (const char *dir, const char *base)
  79 {
  80   if (base != 0)
  81     return base;
  82   if (dir != 0
  83       && access (dir, R_OK | W_OK | X_OK) == 0)
  84     {
  85       /* Check to make sure dir is actually a directory. */
  86 #ifdef S_ISDIR
  87       struct stat s;
  88       if (stat (dir, &s))
  89         return NULL;
  90       if (!S_ISDIR (s.st_mode))
  91         return NULL;
  92 #endif
  93       return dir;
  94     }
  95   return 0;
  96 }
  97
  98 static const char tmp[] = { DIR_SEPARATOR, 't', 'm', 'p', 0 };
  99 static const char vartmp[] =
 100 { DIR_SEPARATOR, 'v', 'a', 'r', DIR_SEPARATOR, 't', 'm', 'p', 0 };
 101
 102 #endif
 103
 104 static char *memoized_tmpdir;
 105
 106 /*
 107
 108 @deftypefn Replacement const char* choose_tmpdir ()
 109
 110 Returns a pointer to a directory path suitable for creating temporary
 111 files in.
 112
 113 @end deftypefn
 114
 115 */
 116
 117 const char *
 118 choose_tmpdir (void)
 119 {
 120   if (!memoized_tmpdir)
 121     {
 122 #if !defined(_WIN32) || defined(__CYGWIN__)
 123       const char *base = 0;
 124       char *tmpdir;
 125       unsigned int len;
 126
 127 #ifdef VMS
 128       /* Try VMS standard temp logical.  */
 129       base = try_dir ("/sys$scratch", base);
 130 #else
 131       base = try_dir (getenv ("TMPDIR"), base);
 132       base = try_dir (getenv ("TMP"), base);
 133       base = try_dir (getenv ("TEMP"), base);
 134 #endif
 135
 136 #ifdef P_tmpdir
 137       /* We really want a directory name here as if concatenated with say \dir
 138          we do not end up with a double \\ which defines an UNC path.  */
 139       if (strcmp (P_tmpdir, "\\") == 0)
 140         base = try_dir ("\\.", base);
 141       else
 142         base = try_dir (P_tmpdir, base);
 143 #endif
 144
 145       /* Try /var/tmp, then /tmp.  */
 146       base = try_dir (vartmp, base);
 147       base = try_dir (tmp, base);
 148
 149       /* If all else fails, use the current directory!  */
 150       if (base == 0)
 151         base = ".";
 152       /* Append DIR_SEPARATOR to the directory we've chosen
 153          and return it.  */
 154       len = strlen (base);
 155       tmpdir = XNEWVEC (char, len + 2);
 156       strcpy (tmpdir, base);
 157       tmpdir[len] = DIR_SEPARATOR;
 158       tmpdir[len+1] = '\0';
 159       memoized_tmpdir = tmpdir;
 160 #else /* defined(_WIN32) && !defined(__CYGWIN__) */
 161       DWORD len;
 162
 163       /* Figure out how much space we need.  */
 164       len = GetTempPath(0, NULL);
 165       if (len)
 166         {
 167           memoized_tmpdir = XNEWVEC (char, len);
 168           if (!GetTempPath(len, memoized_tmpdir))
 169             {
 170               XDELETEVEC (memoized_tmpdir);
 171               memoized_tmpdir = NULL;
 172             }
 173         }
 174       if (!memoized_tmpdir)
 175         /* If all else fails, use the current directory.  */
 176         memoized_tmpdir = xstrdup (".\\");
 177 #endif /* defined(_WIN32) && !defined(__CYGWIN__) */
 178     }
 179
 180   return memoized_tmpdir;
 181 }
 182
 183 /*
 184
 185 @deftypefn Replacement char* make_temp_file (const char *@var{suffix})
 186
 187 Return a temporary file name (as a string) or @code{NULL} if unable to
 188 create one.  @var{suffix} is a suffix to append to the file name.  The
 189 string is @code{malloc}ed, and the temporary file has been created.
 190
 191 @end deftypefn
 192
 193 */
 194
 195 char *
 196 make_temp_file_with_prefix (const char *prefix, const char *suffix)
 197 {
 198   const char *base = choose_tmpdir ();
 199   char *temp_filename;
 200   int base_len, suffix_len, prefix_len;
 201   int fd;
 202
 203   if (prefix == 0)
 204     prefix = "cc";
 205
 206   if (suffix == 0)
 207     suffix = "";
 208
 209   base_len = strlen (base);
 210   prefix_len = strlen (prefix);
 211   suffix_len = strlen (suffix);
 212
 213   temp_filename = XNEWVEC (char, base_len
 214                            + TEMP_FILE_LEN
 215                            + suffix_len
 216                            + prefix_len + 1);
 217   strcpy (temp_filename, base);
 218   strcpy (temp_filename + base_len, prefix);
 219   strcpy (temp_filename + base_len + prefix_len, TEMP_FILE);
 220   strcpy (temp_filename + base_len + prefix_len + TEMP_FILE_LEN, suffix);
 221
 222   fd = mkstemps (temp_filename, suffix_len);
 223   /* Mkstemps failed.  It may be EPERM, ENOSPC etc.  */
 224   if (fd == -1)
 225     {
 226       fprintf (stderr, "Cannot create temporary file in %s: %s\n",
 227                base, strerror (errno));
 228       abort ();
 229     }
 230   /* We abort on failed close out of sheer paranoia.  */
 231   if (close (fd))
 232     abort ();
 233   return temp_filename;
 234 }
 235
 236 char *
 237 make_temp_file (const char *suffix)
 238 {
 239   return make_temp_file_with_prefix (NULL, suffix);
 240 }