lib/sh/tmpfile.c

   1 /*
   2  * tmpfile.c - functions to create and safely open temp files for the shell.
   3  */
   4
   5 /* Copyright (C) 2000-2020 Free Software Foundation, Inc.
   6
   7    This file is part of GNU Bush, the Bourne Again SHell.
   8
   9    Bush is free software: you can redistribute it and/or modify
  10    it under the terms of the GNU General Public License as published by
  11    the Free Software Foundation, either version 3 of the License, or
  12    (at your option) any later version.
  13
  14    Bush is distributed in the hope that it will be useful,
  15    but WITHOUT ANY WARRANTY; without even the implied warranty of
  16    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17    GNU General Public License for more details.
  18
  19    You should have received a copy of the GNU General Public License
  20    along with Bush.  If not, see <http://www.gnu.org/licenses/>.
  21 */
  22
  23 #include <config.h>
  24
  25 #include <bushtypes.h>
  26 #include <posixstat.h>
  27 #include <posixtime.h>
  28 #include <filecntl.h>
  29
  30 #if defined (HAVE_UNISTD_H)
  31 #  include <unistd.h>
  32 #endif
  33
  34 #include <bushansi.h>
  35
  36 #include <stdio.h>
  37 #include <errno.h>
  38
  39 #include <shell.h>
  40
  41 #ifndef errno
  42 extern int errno;
  43 #endif
  44
  45 #define BASEOPENFLAGS   (O_CREAT | O_TRUNC | O_EXCL | O_BINARY)
  46
  47 #define DEFAULT_TMPDIR          "."     /* bogus default, should be changed */
  48 #define DEFAULT_NAMEROOT        "shtmp"
  49
  50 /* Use ANSI-C rand() interface if random(3) is not available */
  51 #if !HAVE_RANDOM
  52 #define random() rand()
  53 #endif
  54
  55 extern pid_t dollar_dollar_pid;
  56
  57 static char *get_sys_tmpdir PARAMS((void));
  58 static char *get_tmpdir PARAMS((int));
  59
  60 static char *sys_tmpdir = (char *)NULL;
  61 static int ntmpfiles;
  62 static int tmpnamelen = -1;
  63 static unsigned long filenum = 1L;
  64
  65 static char *
  66 get_sys_tmpdir ()
  67 {
  68   if (sys_tmpdir)
  69     return sys_tmpdir;
  70
  71 #ifdef P_tmpdir
  72   sys_tmpdir = P_tmpdir;
  73   if (file_iswdir (sys_tmpdir))
  74     return sys_tmpdir;
  75 #endif
  76
  77   sys_tmpdir = "/tmp";
  78   if (file_iswdir (sys_tmpdir))
  79     return sys_tmpdir;
  80
  81   sys_tmpdir = "/var/tmp";
  82   if (file_iswdir (sys_tmpdir))
  83     return sys_tmpdir;
  84
  85   sys_tmpdir = "/usr/tmp";
  86   if (file_iswdir (sys_tmpdir))
  87     return sys_tmpdir;
  88
  89   sys_tmpdir = DEFAULT_TMPDIR;
  90
  91   return sys_tmpdir;
  92 }
  93
  94 static char *
  95 get_tmpdir (flags)
  96      int flags;
  97 {
  98   char *tdir;
  99
 100   tdir = (flags & MT_USETMPDIR) ? get_string_value ("TMPDIR") : (char *)NULL;
 101   if (tdir && (file_iswdir (tdir) == 0 || strlen (tdir) > PATH_MAX))
 102     tdir = 0;
 103
 104   if (tdir == 0)
 105     tdir = get_sys_tmpdir ();
 106
 107 #if defined (HAVE_PATHCONF) && defined (_PC_NAME_MAX)
 108   if (tmpnamelen == -1)
 109     tmpnamelen = pathconf (tdir, _PC_NAME_MAX);
 110 #else
 111   tmpnamelen = 0;
 112 #endif
 113
 114   return tdir;
 115 }
 116
 117 static void
 118 sh_seedrand ()
 119 {
 120 #if HAVE_RANDOM
 121   int d;
 122   static int seeded = 0;
 123   if (seeded == 0)
 124     {
 125       struct timeval tv;
 126
 127       gettimeofday (&tv, NULL);
 128       srandom (tv.tv_sec ^ tv.tv_usec ^ (getpid () << 16) ^ (uintptr_t)&d);
 129       seeded = 1;
 130     }
 131 #endif
 132 }
 133
 134 char *
 135 sh_mktmpname (nameroot, flags)
 136      char *nameroot;
 137      int flags;
 138 {
 139   char *filename, *tdir, *lroot;
 140   struct stat sb;
 141   int r, tdlen;
 142   static int seeded = 0;
 143
 144   filename = (char *)xmalloc (PATH_MAX + 1);
 145   tdir = get_tmpdir (flags);
 146   tdlen = strlen (tdir);
 147
 148   lroot = nameroot ? nameroot : DEFAULT_NAMEROOT;
 149   if (nameroot == 0)
 150     flags &= ~MT_TEMPLATE;
 151
 152   if ((flags & MT_TEMPLATE) && strlen (nameroot) > PATH_MAX)
 153     flags &= ~MT_TEMPLATE;
 154
 155 #ifdef USE_MKTEMP
 156   if (flags & MT_TEMPLATE)
 157     strcpy (filename, nameroot);
 158   else
 159     sprintf (filename, "%s/%s.XXXXXX", tdir, lroot);
 160   if (mktemp (filename) == 0)
 161     {
 162       free (filename);
 163       filename = NULL;
 164     }
 165 #else  /* !USE_MKTEMP */
 166   sh_seedrand ();
 167   while (1)
 168     {
 169       filenum = (filenum << 1) ^
 170                 (unsigned long) time ((time_t *)0) ^
 171                 (unsigned long) dollar_dollar_pid ^
 172                 (unsigned long) ((flags & MT_USERANDOM) ? random () : ntmpfiles++);
 173       sprintf (filename, "%s/%s-%lu", tdir, lroot, filenum);
 174       if (tmpnamelen > 0 && tmpnamelen < 32)
 175         filename[tdlen + 1 + tmpnamelen] = '\0';
 176 #  ifdef HAVE_LSTAT
 177       r = lstat (filename, &sb);
 178 #  else
 179       r = stat (filename, &sb);
 180 #  endif
 181       if (r < 0 && errno == ENOENT)
 182         break;
 183     }
 184 #endif /* !USE_MKTEMP */
 185
 186   return filename;
 187 }
 188
 189 int
 190 sh_mktmpfd (nameroot, flags, namep)
 191      char *nameroot;
 192      int flags;
 193      char **namep;
 194 {
 195   char *filename, *tdir, *lroot;
 196   int fd, tdlen;
 197
 198   filename = (char *)xmalloc (PATH_MAX + 1);
 199   tdir = get_tmpdir (flags);
 200   tdlen = strlen (tdir);
 201
 202   lroot = nameroot ? nameroot : DEFAULT_NAMEROOT;
 203   if (nameroot == 0)
 204     flags &= ~MT_TEMPLATE;
 205
 206   if ((flags & MT_TEMPLATE) && strlen (nameroot) > PATH_MAX)
 207     flags &= ~MT_TEMPLATE;
 208
 209 #ifdef USE_MKSTEMP
 210   if (flags & MT_TEMPLATE)
 211     strcpy (filename, nameroot);
 212   else
 213     sprintf (filename, "%s/%s.XXXXXX", tdir, lroot);
 214   fd = mkstemp (filename);
 215   if (fd < 0 || namep == 0)
 216     {
 217       free (filename);
 218       filename = NULL;
 219     }
 220   if (namep)
 221     *namep = filename;
 222   return fd;
 223 #else /* !USE_MKSTEMP */
 224   sh_seedrand ();
 225   do
 226     {
 227       filenum = (filenum << 1) ^
 228                 (unsigned long) time ((time_t *)0) ^
 229                 (unsigned long) dollar_dollar_pid ^
 230                 (unsigned long) ((flags & MT_USERANDOM) ? random () : ntmpfiles++);
 231       sprintf (filename, "%s/%s-%lu", tdir, lroot, filenum);
 232       if (tmpnamelen > 0 && tmpnamelen < 32)
 233         filename[tdlen + 1 + tmpnamelen] = '\0';
 234       fd = open (filename, BASEOPENFLAGS | ((flags & MT_READWRITE) ? O_RDWR : O_WRONLY), 0600);
 235     }
 236   while (fd < 0 && errno == EEXIST);
 237
 238   if (namep)
 239     *namep = filename;
 240   else
 241     free (filename);
 242
 243   return fd;
 244 #endif /* !USE_MKSTEMP */
 245 }
 246
 247 FILE *
 248 sh_mktmpfp (nameroot, flags, namep)
 249      char *nameroot;
 250      int flags;
 251      char **namep;
 252 {
 253   int fd;
 254   FILE *fp;
 255
 256   fd = sh_mktmpfd (nameroot, flags, namep);
 257   if (fd < 0)
 258     return ((FILE *)NULL);
 259   fp = fdopen (fd, (flags & MT_READWRITE) ? "w+" : "w");
 260   if (fp == 0)
 261     close (fd);
 262   return fp;
 263 }
 264
 265 char *
 266 sh_mktmpdir (nameroot, flags)
 267      char *nameroot;
 268      int flags;
 269 {
 270   char *filename, *tdir, *lroot, *dirname;
 271   int fd, tdlen;
 272
 273 #ifdef USE_MKDTEMP
 274   filename = (char *)xmalloc (PATH_MAX + 1);
 275   tdir = get_tmpdir (flags);
 276   tdlen = strlen (tdir);
 277
 278   lroot = nameroot ? nameroot : DEFAULT_NAMEROOT;
 279   if (nameroot == 0)
 280     flags &= ~MT_TEMPLATE;
 281
 282   if ((flags & MT_TEMPLATE) && strlen (nameroot) > PATH_MAX)
 283     flags &= ~MT_TEMPLATE;
 284
 285   if (flags & MT_TEMPLATE)
 286     strcpy (filename, nameroot);
 287   else
 288     sprintf (filename, "%s/%s.XXXXXX", tdir, lroot);
 289   dirname = mkdtemp (filename);
 290   if (dirname == 0)
 291     {
 292       free (filename);
 293       filename = NULL;
 294     }
 295   return dirname;
 296 #else /* !USE_MKDTEMP */
 297   filename = (char *)NULL;
 298   do
 299     {
 300       filename = sh_mktmpname (nameroot, flags);
 301       fd = mkdir (filename, 0700);
 302       if (fd == 0)
 303         break;
 304       free (filename);
 305       filename = (char *)NULL;
 306     }
 307   while (fd < 0 && errno == EEXIST);
 308
 309   return (filename);
 310 #endif /* !USE_MKDTEMP */
 311 }