libiberty/choose-temp.c

   1 /* Utility to pick a temporary filename prefix.
   2    Copyright (C) 1996, 1997, 1998 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., 59 Temple Place - Suite 330,
  18 Boston, MA 02111-1307, USA.  */
  19
  20 /* This file exports two functions: choose_temp_base and make_temp_file.  */
  21
  22 /* This file lives in at least two places: libiberty and gcc.
  23    Don't change one without the other.  */
  24
  25 #ifdef HAVE_CONFIG_H
  26 #include "config.h"
  27 #endif
  28
  29 #include <stdio.h>      /* May get P_tmpdir.  */
  30 #include <sys/types.h>
  31 #ifdef HAVE_UNISTD_H
  32 #include <unistd.h>
  33 #endif
  34 #ifdef HAVE_STDLIB_H
  35 #include <stdlib.h>
  36 #endif
  37 #ifdef HAVE_STRING_H
  38 #include <string.h>
  39 #endif
  40 #ifdef HAVE_SYS_FILE_H
  41 #include <sys/file.h>   /* May get R_OK, etc. on some systems.  */
  42 #endif
  43
  44 #ifndef R_OK
  45 #define R_OK 4
  46 #define W_OK 2
  47 #define X_OK 1
  48 #endif
  49
  50 #include "libiberty.h"
  51 extern int mkstemps ();
  52
  53 #ifndef IN_GCC
  54 #if defined (__MSDOS__) || defined (_WIN32)
  55 #define DIR_SEPARATOR '\\'
  56 #endif
  57 #endif
  58
  59 #ifndef DIR_SEPARATOR
  60 #define DIR_SEPARATOR '/'
  61 #endif
  62
  63 /* On MSDOS, write temp files in current dir
  64    because there's no place else we can expect to use.  */
  65 /* ??? Although the current directory is tried as a last resort,
  66    this is left in so that on MSDOS it is preferred to /tmp on the
  67    off chance that someone requires this, since that was the previous
  68    behaviour.  */
  69 #ifdef __MSDOS__
  70 #ifndef P_tmpdir
  71 #define P_tmpdir "."
  72 #endif
  73 #endif
  74
  75 /* Name of temporary file.
  76    mktemp requires 6 trailing X's.  */
  77 #define TEMP_FILE "ccXXXXXX"
  78
  79 /* Subroutine of choose_temp_base.
  80    If BASE is non-NULL, return it.
  81    Otherwise it checks if DIR is a usable directory.
  82    If success, DIR is returned.
  83    Otherwise NULL is returned.  */
  84
  85 static char *
  86 try (dir, base)
  87      char *dir, *base;
  88 {
  89   if (base != 0)
  90     return base;
  91   if (dir != 0
  92       && access (dir, R_OK | W_OK | X_OK) == 0)
  93     return dir;
  94   return 0;
  95 }
  96
  97 /* Return a prefix for temporary file names or NULL if unable to find one.
  98    The current directory is chosen if all else fails so the program is
  99    exited if a temporary directory can't be found (mktemp fails).
 100    The buffer for the result is obtained with xmalloc.
 101
 102    This function is provided for backwards compatability only.  It use
 103    is not recommended.  */
 104
 105 char *
 106 choose_temp_base ()
 107 {
 108   char *base = 0;
 109   char *temp_filename;
 110   int len;
 111   static char tmp[] = { DIR_SEPARATOR, 't', 'm', 'p', 0 };
 112   static char usrtmp[] = { DIR_SEPARATOR, 'u', 's', 'r', DIR_SEPARATOR, 't', 'm', 'p', 0 };
 113
 114   base = try (getenv ("TMPDIR"), base);
 115   base = try (getenv ("TMP"), base);
 116   base = try (getenv ("TEMP"), base);
 117
 118 #ifdef P_tmpdir
 119   base = try (P_tmpdir, base);
 120 #endif
 121
 122   /* Try /usr/tmp, then /tmp.  */
 123   base = try (usrtmp, base);
 124   base = try (tmp, base);
 125
 126   /* If all else fails, use the current directory!  */
 127   if (base == 0)
 128     base = ".";
 129
 130   len = strlen (base);
 131   temp_filename = xmalloc (len + 1 /*DIR_SEPARATOR*/
 132                            + strlen (TEMP_FILE) + 1);
 133   strcpy (temp_filename, base);
 134
 135   if (len != 0
 136       && temp_filename[len-1] != '/'
 137       && temp_filename[len-1] != DIR_SEPARATOR)
 138     temp_filename[len++] = DIR_SEPARATOR;
 139   strcpy (temp_filename + len, TEMP_FILE);
 140
 141   mktemp (temp_filename);
 142   if (strlen (temp_filename) == 0)
 143     abort ();
 144   return temp_filename;
 145 }
 146 /* Return a temporary file name (as a string) or NULL if unable to create
 147    one.  */
 148
 149 char *
 150 make_temp_file (suffix)
 151      char *suffix;
 152 {
 153   char *base = 0;
 154   char *temp_filename;
 155   int base_len, suffix_len;
 156   int fd;
 157   static char tmp[] = { DIR_SEPARATOR, 't', 'm', 'p', 0 };
 158   static char usrtmp[] = { DIR_SEPARATOR, 'u', 's', 'r', DIR_SEPARATOR, 't', 'm', 'p', 0 };
 159
 160   base = try (getenv ("TMPDIR"), base);
 161   base = try (getenv ("TMP"), base);
 162   base = try (getenv ("TEMP"), base);
 163
 164 #ifdef P_tmpdir
 165   base = try (P_tmpdir, base);
 166 #endif
 167
 168   /* Try /usr/tmp, then /tmp.  */
 169   base = try (usrtmp, base);
 170   base = try (tmp, base);
 171
 172   /* If all else fails, use the current directory!  */
 173   if (base == 0)
 174     base = ".";
 175
 176   base_len = strlen (base);
 177
 178   if (suffix)
 179     suffix_len = strlen (suffix);
 180   else
 181     suffix_len = 0;
 182
 183   temp_filename = xmalloc (base_len + 1 /*DIR_SEPARATOR*/
 184                            + strlen (TEMP_FILE)
 185                            + suffix_len + 1);
 186   strcpy (temp_filename, base);
 187
 188   if (base_len != 0
 189       && temp_filename[base_len-1] != '/'
 190       && temp_filename[base_len-1] != DIR_SEPARATOR)
 191     temp_filename[base_len++] = DIR_SEPARATOR;
 192   strcpy (temp_filename + base_len, TEMP_FILE);
 193
 194   if (suffix)
 195     strcat (temp_filename, suffix);
 196
 197   fd = mkstemps (temp_filename, suffix_len);
 198   /* If mkstemps failed, then something bad is happening.  Maybe we should
 199      issue a message about a possible security attack in progress?  */
 200   if (fd == -1)
 201     abort ();
 202   /* Similarly if we can not close the file.  */
 203   if (close (fd))
 204     abort ();
 205   return temp_filename;
 206 }