libiberty/make-temp-file.c

   1 /* Utility to pick a temporary filename prefix.
   2    Copyright (C) 1996-2022 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 #include <windows.h>
  41 #endif
  42 #if HAVE_SYS_STAT_H
  43 #include <sys/stat.h>
  44 #endif
  45
  46
  47 #ifndef R_OK
  48 #define R_OK 4
  49 #define W_OK 2
  50 #define X_OK 1
  51 #endif
  52
  53 #include "libiberty.h"
  54 extern int mkstemps (char *, int);
  55
  56 /* '/' works just fine on MS-DOS based systems.  */
  57 #ifndef DIR_SEPARATOR
  58 #define DIR_SEPARATOR '/'
  59 #endif
  60
  61 /* Name of temporary file.
  62    mktemp requires 6 trailing X's.  */
  63 #define TEMP_FILE "XXXXXX"
  64 #define TEMP_FILE_LEN (sizeof(TEMP_FILE) - 1)
  65
  66 #if !defined(_WIN32) || defined(__CYGWIN__)
  67
  68 /* Subroutine of choose_tmpdir.
  69    If BASE is non-NULL, return it.
  70    Otherwise it checks if DIR is a usable directory.
  71    If success, DIR is returned.
  72    Otherwise NULL is returned.  */
  73
  74 static inline const char *try_dir (const char *, const char *);
  75
  76 static inline const char *
  77 try_dir (const char *dir, const char *base)
  78 {
  79   if (base != 0)
  80     return base;
  81   if (dir != 0
  82       && access (dir, R_OK | W_OK | X_OK) == 0)
  83     {
  84       /* Check to make sure dir is actually a directory. */
  85 #ifdef S_ISDIR
  86       struct stat s;
  87       if (stat (dir, &s))
  88         return NULL;
  89       if (!S_ISDIR (s.st_mode))
  90         return NULL;
  91 #endif
  92       return dir;
  93     }
  94   return 0;
  95 }
  96
  97 static const char tmp[] = { DIR_SEPARATOR, 't', 'm', 'p', 0 };
  98 static const char vartmp[] =
  99 { DIR_SEPARATOR, 'v', 'a', 'r', DIR_SEPARATOR, 't', 'm', 'p', 0 };
 100
 101 #endif
 102
 103 static char *memoized_tmpdir;
 104
 105 /*
 106
 107 @deftypefn Replacement const char* choose_tmpdir ()
 108
 109 Returns a pointer to a directory path suitable for creating temporary
 110 files in.
 111
 112 @end deftypefn
 113
 114 */
 115
 116 const char *
 117 choose_tmpdir (void)
 118 {
 119   if (!memoized_tmpdir)
 120     {
 121 #if !defined(_WIN32) || defined(__CYGWIN__)
 122       const char *base = 0;
 123       char *tmpdir;
 124       unsigned int len;
 125
 126 #ifdef VMS
 127       /* Try VMS standard temp logical.  */
 128       base = try_dir ("/sys$scratch", base);
 129 #else
 130       base = try_dir (getenv ("TMPDIR"), base);
 131       base = try_dir (getenv ("TMP"), base);
 132       base = try_dir (getenv ("TEMP"), base);
 133 #endif
 134
 135 #ifdef P_tmpdir
 136       /* We really want a directory name here as if concatenated with say \dir
 137          we do not end up with a double \\ which defines an UNC path.  */
 138       if (strcmp (P_tmpdir, "\\") == 0)
 139         base = try_dir ("\\.", base);
 140       else
 141         base = try_dir (P_tmpdir, base);
 142 #endif
 143
 144       /* Try /var/tmp, then /tmp.  */
 145       base = try_dir (vartmp, base);
 146       base = try_dir (tmp, base);
 147
 148       /* If all else fails, use the current directory!  */
 149       if (base == 0)
 150         base = ".";
 151       /* Append DIR_SEPARATOR to the directory we've chosen
 152          and return it.  */
 153       len = strlen (base);
 154       tmpdir = XNEWVEC (char, len + 2);
 155       strcpy (tmpdir, base);
 156       tmpdir[len] = DIR_SEPARATOR;
 157       tmpdir[len+1] = '\0';
 158       memoized_tmpdir = tmpdir;
 159 #else /* defined(_WIN32) && !defined(__CYGWIN__) */
 160       DWORD len;
 161
 162       /* Figure out how much space we need.  */
 163       len = GetTempPath(0, NULL);
 164       if (len)
 165         {
 166           memoized_tmpdir = XNEWVEC (char, len);
 167           if (!GetTempPath(len, memoized_tmpdir))
 168             {
 169               XDELETEVEC (memoized_tmpdir);
 170               memoized_tmpdir = NULL;
 171             }
 172         }
 173       if (!memoized_tmpdir)
 174         /* If all else fails, use the current directory.  */
 175         memoized_tmpdir = xstrdup (".\\");
 176 #endif /* defined(_WIN32) && !defined(__CYGWIN__) */
 177     }
 178
 179   return memoized_tmpdir;
 180 }
 181
 182 /*
 183
 184 @deftypefn Replacement char* make_temp_file (const char *@var{suffix})
 185
 186 Return a temporary file name (as a string) or @code{NULL} if unable to
 187 create one.  @var{suffix} is a suffix to append to the file name.  The
 188 string is @code{malloc}ed, and the temporary file has been created.
 189
 190 @end deftypefn
 191
 192 */
 193
 194 char *
 195 make_temp_file_with_prefix (const char *prefix, const char *suffix)
 196 {
 197   const char *base = choose_tmpdir ();
 198   char *temp_filename;
 199   int base_len, suffix_len, prefix_len;
 200   int fd;
 201
 202   if (prefix == 0)
 203     prefix = "cc";
 204
 205   if (suffix == 0)
 206     suffix = "";
 207
 208   base_len = strlen (base);
 209   prefix_len = strlen (prefix);
 210   suffix_len = strlen (suffix);
 211
 212   temp_filename = XNEWVEC (char, base_len
 213                            + TEMP_FILE_LEN
 214                            + suffix_len
 215                            + prefix_len + 1);
 216   strcpy (temp_filename, base);
 217   strcpy (temp_filename + base_len, prefix);
 218   strcpy (temp_filename + base_len + prefix_len, TEMP_FILE);
 219   strcpy (temp_filename + base_len + prefix_len + TEMP_FILE_LEN, suffix);
 220
 221   fd = mkstemps (temp_filename, suffix_len);
 222   /* Mkstemps failed.  It may be EPERM, ENOSPC etc.  */
 223   if (fd == -1)
 224     {
 225       fprintf (stderr, "Cannot create temporary file in %s: %s\n",
 226                base, strerror (errno));
 227       abort ();
 228     }
 229   /* We abort on failed close out of sheer paranoia.  */
 230   if (close (fd))
 231     abort ();
 232   return temp_filename;
 233 }
 234
 235 char *
 236 make_temp_file (const char *suffix)
 237 {
 238   return make_temp_file_with_prefix (NULL, suffix);
 239 }