gcc/choose-temp.c

   1 /* Utility to pick a temporary filename prefix.
   2    Copyright (C) 1996 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 one function: choose_temp_base.  */
  21
  22 /* This file lives in at least two places: libiberty and gcc.
  23    Don't change one without the other.  */
  24
  25 #ifndef NO_SYS_FILE_H
  26 #include <sys/types.h>
  27 #include <sys/file.h>   /* May get R_OK, etc. on some systems.  */
  28 #endif
  29
  30 #ifndef R_OK
  31 #define R_OK 4
  32 #define W_OK 2
  33 #define X_OK 1
  34 #endif
  35
  36 #include <stdio.h>      /* May get P_tmpdir.  */
  37
  38 #ifdef IN_GCC
  39 #include "config.h"
  40 #include "gansidecl.h"
  41 extern char *xmalloc ();
  42 #else
  43 #include "ansidecl.h"
  44 #include "libiberty.h"
  45 #if defined (__MSDOS__) || defined (_WIN32)
  46 #define DIR_SEPARATOR '\\'
  47 #endif
  48 #endif
  49
  50 #ifndef DIR_SEPARATOR
  51 #define DIR_SEPARATOR '/'
  52 #endif
  53
  54 /* On MSDOS, write temp files in current dir
  55    because there's no place else we can expect to use.  */
  56 /* ??? Although the current directory is tried as a last resort,
  57    this is left in so that on MSDOS it is prefered to /tmp on the
  58    off chance that someone requires this, since that was the previous
  59    behaviour.  */
  60 #ifdef __MSDOS__
  61 #ifndef P_tmpdir
  62 #define P_tmpdir "."
  63 #endif
  64 #endif
  65
  66 /* Name of temporary file.
  67    mktemp requires 6 trailing X's.  */
  68 #define TEMP_FILE "ccXXXXXX"
  69
  70 /* Subroutine of choose_temp_base.
  71    If BASE is non-NULL, returh it.
  72    Otherwise it checks if DIR is a usable directory.
  73    If success, DIR is returned.
  74    Otherwise NULL is returned.  */
  75
  76 static char *
  77 try (dir, base)
  78      char *dir, *base;
  79 {
  80   if (base != 0)
  81     return base;
  82   if (dir != 0
  83       && access (dir, R_OK | W_OK | X_OK) == 0)
  84     return dir;
  85   return 0;
  86 }
  87
  88 /* Return a prefix for temporary file names or NULL if unable to find one.
  89    The current directory is chosen if all else fails so the program is
  90    exited if a temporary directory can't be found (mktemp fails).
  91    The buffer for the result is obtained with xmalloc.  */
  92
  93 char *
  94 choose_temp_base ()
  95 {
  96   char *base = 0;
  97   char *temp_filename;
  98   int len;
  99   static char tmp[] = { DIR_SEPARATOR, 't', 'm', 'p', 0 };
 100   static char usrtmp[] = { DIR_SEPARATOR, 'u', 's', 'r', DIR_SEPARATOR, 't', 'm', 'p', 0 };
 101
 102 #ifndef MPW
 103   base = try (getenv ("TMPDIR"), base);
 104   base = try (getenv ("TMP"), base);
 105   base = try (getenv ("TEMP"), base);
 106
 107 #ifdef P_tmpdir
 108   base = try (P_tmpdir, base);
 109 #endif
 110
 111   /* Try /usr/tmp, then /tmp.  */
 112   base = try (usrtmp, base);
 113   base = try (tmp, base);
 114
 115   /* If all else fails, use the current directory!  */
 116   if (base == 0)
 117 #ifdef VMS
 118     base = "[";
 119 #else
 120     base = ".";
 121 #endif
 122
 123 #else /* MPW */
 124   base = ":";
 125 #endif
 126
 127   len = strlen (base);
 128   temp_filename = xmalloc (len + 1 /*DIR_SEPARATOR*/
 129                            + strlen (TEMP_FILE) + 1);
 130   strcpy (temp_filename, base);
 131
 132 #ifndef MPW
 133   if (len != 0
 134       && temp_filename[len-1] != '/'
 135       && temp_filename[len-1] != DIR_SEPARATOR)
 136     temp_filename[len++] = DIR_SEPARATOR;
 137 #else /* MPW */
 138   if (temp_filename[len-1] != ':')
 139     temp_filename[len++] = ':';
 140 #endif /* MPW */
 141   strcpy (temp_filename + len, TEMP_FILE);
 142
 143   mktemp (temp_filename);
 144   if (strlen (temp_filename) == 0)
 145     abort ();
 146   return temp_filename;
 147 }