1 /* Utility to pick a temporary filename prefix. 2 Copyright (C) 1996, 1997, 1998, 2001 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 40 #ifndef R_OK 41 #define R_OK 4 42 #define W_OK 2 43 #define X_OK 1 44 #endif 45 46 #include "libiberty.h" 47 extern int mkstemps (char *, int); 48 49 /* '/' works just fine on MS-DOS based systems. */ 50 #ifndef DIR_SEPARATOR 51 #define DIR_SEPARATOR '/' 52 #endif 53 54 /* Name of temporary file. 55 mktemp requires 6 trailing X's. */ 56 #define TEMP_FILE "ccXXXXXX" 57 #define TEMP_FILE_LEN (sizeof(TEMP_FILE) - 1) 58 59 /* Subroutine of choose_tmpdir. 60 If BASE is non-NULL, return it. 61 Otherwise it checks if DIR is a usable directory. 62 If success, DIR is returned. 63 Otherwise NULL is returned. */ 64 65 static inline const char *try_dir (const char *, const char *); 66 67 static inline const char * 68 try_dir (const char *dir, const char *base) 69 { 70 if (base != 0) 71 return base; 72 if (dir != 0 73 && access (dir, R_OK | W_OK | X_OK) == 0) 74 return dir; 75 return 0; 76 } 77 78 static const char tmp[] = { DIR_SEPARATOR, 't', 'm', 'p', 0 }; 79 static const char usrtmp[] = 80 { DIR_SEPARATOR, 'u', 's', 'r', DIR_SEPARATOR, 't', 'm', 'p', 0 }; 81 static const char vartmp[] = 82 { DIR_SEPARATOR, 'v', 'a', 'r', DIR_SEPARATOR, 't', 'm', 'p', 0 }; 83 84 static char *memoized_tmpdir; 85 86 /* 87 88 @deftypefn Replacement char* choose_tmpdir () 89 90 Returns a pointer to a directory path suitable for creating temporary 91 files in. 92 93 @end deftypefn 94 95 */ 96 97 char * 98 choose_tmpdir (void) 99 { 100 const char *base = 0; 101 char *tmpdir; 102 unsigned int len; 103 104 if (memoized_tmpdir) 105 return memoized_tmpdir; 106 107 base = try_dir (getenv ("TMPDIR"), base); 108 base = try_dir (getenv ("TMP"), base); 109 base = try_dir (getenv ("TEMP"), base); 110 111 #ifdef P_tmpdir 112 base = try_dir (P_tmpdir, base); 113 #endif 114 115 /* Try /var/tmp, /usr/tmp, then /tmp. */ 116 base = try_dir (vartmp, base); 117 base = try_dir (usrtmp, base); 118 base = try_dir (tmp, base); 119 120 /* If all else fails, use the current directory! */ 121 if (base == 0) 122 base = "."; 123 124 /* Append DIR_SEPARATOR to the directory we've chosen 125 and return it. */ 126 len = strlen (base); 127 tmpdir = XNEWVEC (char, len + 2); 128 strcpy (tmpdir, base); 129 tmpdir[len] = DIR_SEPARATOR; 130 tmpdir[len+1] = '\0'; 131 132 memoized_tmpdir = tmpdir; 133 return tmpdir; 134 } 135 136 /* 137 138 @deftypefn Replacement char* make_temp_file (const char *@var{suffix}) 139 140 Return a temporary file name (as a string) or @code{NULL} if unable to 141 create one. @var{suffix} is a suffix to append to the file name. The 142 string is @code{malloc}ed, and the temporary file has been created. 143 144 @end deftypefn 145 146 */ 147 148 char * 149 make_temp_file (const char *suffix) 150 { 151 const char *base = choose_tmpdir (); 152 char *temp_filename; 153 int base_len, suffix_len; 154 int fd; 155 156 if (suffix == 0) 157 suffix = ""; 158 159 base_len = strlen (base); 160 suffix_len = strlen (suffix); 161 162 temp_filename = XNEWVEC (char, base_len 163 + TEMP_FILE_LEN 164 + suffix_len + 1); 165 strcpy (temp_filename, base); 166 strcpy (temp_filename + base_len, TEMP_FILE); 167 strcpy (temp_filename + base_len + TEMP_FILE_LEN, suffix); 168 169 fd = mkstemps (temp_filename, suffix_len); 170 /* Mkstemps failed. It may be EPERM, ENOSPC etc. */ 171 if (fd == -1) 172 { 173 fprintf (stderr, "Cannot create temporary file in %s: %s\n", 174 base, strerror (errno)); 175 abort (); 176 } 177 /* We abort on failed close out of sheer paranoia. */ 178 if (close (fd)) 179 abort (); 180 return temp_filename; 181 } 182