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
  17 not, 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 #if ! defined (_WIN32) && ! defined (NO_SYS_FILE_H)
  23 #include <sys/file.h>   /* May get R_OK, etc. on some systems.  */
  24 #endif
  25
  26 #ifndef R_OK
  27 #define R_OK 4
  28 #define W_OK 2
  29 #define X_OK 1
  30 #endif
  31
  32 #include <stdio.h>      /* May get P_tmpdir.  */
  33
  34 #ifdef IN_GCC
  35 #include "config.h"
  36 #include "gansidecl.h"
  37 extern char *xmalloc ();
  38 #else
  39 #include "ansidecl.h"
  40 #include "libiberty.h"
  41 #if defined (__MSDOS__) || defined (_WIN32)
  42 #define DIR_SEPARATOR '\\'
  43 #endif
  44 #endif
  45
  46 #ifndef DIR_SEPARATOR
  47 #define DIR_SEPARATOR '/'
  48 #endif
  49
  50 /* On MSDOS, write temp files in current dir
  51    because there's no place else we can expect to use.  */
  52 /* ??? Although the current directory is tried as a last resort,
  53    this is left in so that on MSDOS it is prefered to /tmp on the
  54    off chance that someone requires this, since that was the previous
  55    behaviour.  */
  56 #ifdef __MSDOS__
  57 #ifndef P_tmpdir
  58 #define P_tmpdir "."
  59 #endif
  60 #endif
  61
  62 /* Name of temporary file.
  63    mktemp requires 6 trailing X's.  */
  64 #define TEMP_FILE "ccXXXXXX"
  65
  66 /* Subroutine of choose_temp_base.
  67    If BASE is non-NULL, returh it.
  68    Otherwise it checks if DIR is a usable directory.
  69    If success, DIR is returned.
  70    Otherwise NULL is returned.  */
  71
  72 static char *
  73 try (dir, base)
  74      char *dir, *base;
  75 {
  76   if (base != 0)
  77     return base;
  78   if (dir != 0
  79       && access (dir, R_OK | W_OK) == 0)
  80     return dir;
  81   return 0;
  82 }
  83
  84 /* Return a prefix for temporary file names or NULL if unable to find one.
  85    The current directory is chosen if all else fails so the program is
  86    exited if a temporary directory can't be found (mktemp fails).
  87    The buffer for the result is obtained with xmalloc.  */
  88
  89 char *
  90 choose_temp_base ()
  91 {
  92   char *base = 0;
  93   char *temp_filename;
  94   int len;
  95   static char tmp[] = { DIR_SEPARATOR, 't', 'm', 'p', 0 };
  96   static char usrtmp[] = { DIR_SEPARATOR, 'u', 's', 'r', DIR_SEPARATOR, 't', 'm', 'p', 0 };
  97
  98 #ifndef MPW
  99   base = try (getenv ("TMPDIR"), base);
 100   base = try (getenv ("TMP"), base);
 101   base = try (getenv ("TEMP"), base);
 102
 103 #ifdef P_tmpdir
 104   base = try (P_tmpdir, base);
 105 #endif
 106
 107   /* Try /usr/tmp, then /tmp.  */
 108   base = try (usrtmp, base);
 109   base = try (tmp, base);
 110
 111   /* If all else fails, use the current directory!  */
 112   if (base == 0)
 113     base = ".";
 114
 115 #else /* MPW */
 116   base = ":";
 117 #endif
 118
 119   len = strlen (base);
 120   if (len == 0)
 121     abort ();
 122   temp_filename = xmalloc (len + 1 /*DIR_SEPARATOR*/
 123                            + strlen (TEMP_FILE) + 1);
 124   strcpy (temp_filename, base);
 125
 126 #ifndef MPW
 127   if (temp_filename[len-1] != '/'
 128       && temp_filename[len-1] != DIR_SEPARATOR)
 129     temp_filename[len++] = DIR_SEPARATOR;
 130 #else /* MPW */
 131   if (temp_filename[len-1] != ':')
 132     temp_filename[len++] = ':';
 133 #endif /* MPW */
 134   strcpy (temp_filename + len, TEMP_FILE);
 135
 136   mktemp (temp_filename);
 137   if (strlen (temp_filename) == 0)
 138     abort ();
 139   return temp_filename;
 140 }