gcc/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 #if defined (IN_GCC) || defined (HAVE_CONFIG_H)
  26 #include "config.h"
  27 #endif
  28
  29 #ifdef IN_GCC
  30 #include "system.h"
  31 #else
  32
  33 /* If we are in gcc, system.h has handled everything.  When not in
  34    gcc, if we have a config.h we assume that HAVE_SYS_FILE_H tells us
  35    whether to include sys/file.h.  However, libiberty does not have a
  36    config.h, and instead arranges to define NO_SYS_FILE_H on the
  37    command line when there is no sys/file.h.  */
  38
  39 #if defined (HAVE_CONFIG_H) ? defined (HAVE_SYS_FILE_H) : ! defined (NO_SYS_FILE_H)
  40 #include <sys/types.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 <stdio.h>      /* May get P_tmpdir.  */
  51 #endif /* IN_GCC */
  52
  53 #ifdef IN_GCC
  54 #include "gansidecl.h"
  55 extern char *xmalloc ();
  56 #else
  57 #include "ansidecl.h"
  58 #include "libiberty.h"
  59 #if defined (__MSDOS__) || defined (_WIN32)
  60 #define DIR_SEPARATOR '\\'
  61 #endif
  62 #endif
  63
  64 #ifndef DIR_SEPARATOR
  65 #define DIR_SEPARATOR '/'
  66 #endif
  67
  68 /* On MSDOS, write temp files in current dir
  69    because there's no place else we can expect to use.  */
  70 /* ??? Although the current directory is tried as a last resort,
  71    this is left in so that on MSDOS it is preferred to /tmp on the
  72    off chance that someone requires this, since that was the previous
  73    behaviour.  */
  74 #ifdef __MSDOS__
  75 #ifndef P_tmpdir
  76 #define P_tmpdir "."
  77 #endif
  78 #endif
  79
  80 /* Name of temporary file.
  81    mktemp requires 6 trailing X's.  */
  82 #define TEMP_FILE "ccXXXXXX"
  83
  84 /* Subroutine of choose_temp_base.
  85    If BASE is non-NULL, return it.
  86    Otherwise it checks if DIR is a usable directory.
  87    If success, DIR is returned.
  88    Otherwise NULL is returned.  */
  89
  90 static char *
  91 try (dir, base)
  92      char *dir, *base;
  93 {
  94   if (base != 0)
  95     return base;
  96   if (dir != 0
  97       && access (dir, R_OK | W_OK | X_OK) == 0)
  98     return dir;
  99   return 0;
 100 }
 101
 102 /* Return a prefix for temporary file names or NULL if unable to find one.
 103    The current directory is chosen if all else fails so the program is
 104    exited if a temporary directory can't be found (mktemp fails).
 105    The buffer for the result is obtained with xmalloc.
 106
 107    This function is provided for backwards compatability only.  It use
 108    is not recommended.  */
 109
 110 char *
 111 choose_temp_base ()
 112 {
 113   char *base = 0;
 114   char *temp_filename;
 115   int len;
 116   static char tmp[] = { DIR_SEPARATOR, 't', 'm', 'p', 0 };
 117   static char usrtmp[] = { DIR_SEPARATOR, 'u', 's', 'r', DIR_SEPARATOR, 't', 'm', 'p', 0 };
 118
 119   base = try (getenv ("TMPDIR"), base);
 120   base = try (getenv ("TMP"), base);
 121   base = try (getenv ("TEMP"), base);
 122
 123 #ifdef P_tmpdir
 124   base = try (P_tmpdir, base);
 125 #endif
 126
 127   /* Try /usr/tmp, then /tmp.  */
 128   base = try (usrtmp, base);
 129   base = try (tmp, base);
 130
 131   /* If all else fails, use the current directory!  */
 132   if (base == 0)
 133     base = ".";
 134
 135   len = strlen (base);
 136   temp_filename = xmalloc (len + 1 /*DIR_SEPARATOR*/
 137                            + strlen (TEMP_FILE) + 1);
 138   strcpy (temp_filename, base);
 139
 140   if (len != 0
 141       && temp_filename[len-1] != '/'
 142       && temp_filename[len-1] != DIR_SEPARATOR)
 143     temp_filename[len++] = DIR_SEPARATOR;
 144   strcpy (temp_filename + len, TEMP_FILE);
 145
 146   mktemp (temp_filename);
 147   if (strlen (temp_filename) == 0)
 148     abort ();
 149   return temp_filename;
 150 }
 151 /* Return a temporary file name (as a string) or NULL if unable to create
 152    one.  */
 153
 154 char *
 155 make_temp_file (suffix)
 156      char *suffix;
 157 {
 158   char *base = 0;
 159   char *temp_filename;
 160   int base_len, suffix_len;
 161   int fd;
 162   static char tmp[] = { DIR_SEPARATOR, 't', 'm', 'p', 0 };
 163   static char usrtmp[] = { DIR_SEPARATOR, 'u', 's', 'r', DIR_SEPARATOR, 't', 'm', 'p', 0 };
 164
 165   base = try (getenv ("TMPDIR"), base);
 166   base = try (getenv ("TMP"), base);
 167   base = try (getenv ("TEMP"), base);
 168
 169 #ifdef P_tmpdir
 170   base = try (P_tmpdir, base);
 171 #endif
 172
 173   /* Try /usr/tmp, then /tmp.  */
 174   base = try (usrtmp, base);
 175   base = try (tmp, base);
 176
 177   /* If all else fails, use the current directory!  */
 178   if (base == 0)
 179     base = ".";
 180
 181   base_len = strlen (base);
 182
 183   if (suffix)
 184     suffix_len = strlen (suffix);
 185   else
 186     suffix_len = 0;
 187
 188   temp_filename = xmalloc (base_len + 1 /*DIR_SEPARATOR*/
 189                            + strlen (TEMP_FILE)
 190                            + suffix_len + 1);
 191   strcpy (temp_filename, base);
 192
 193   if (base_len != 0
 194       && temp_filename[base_len-1] != '/'
 195       && temp_filename[base_len-1] != DIR_SEPARATOR)
 196     temp_filename[base_len++] = DIR_SEPARATOR;
 197   strcpy (temp_filename + base_len, TEMP_FILE);
 198
 199   if (suffix)
 200     strcat (temp_filename, suffix);
 201
 202   fd = mkstemps (temp_filename, suffix_len);
 203   /* If mkstemps failed, then something bad is happening.  Maybe we should
 204      issue a message about a possible security attack in progress?  */
 205   if (fd == -1)
 206     abort ();
 207   /* Similarly if we can not close the file.  */
 208   if (close (fd))
 209     abort ();
 210   return temp_filename;
 211 }