lib/relocwrapper.c

   1 /* Relocating wrapper program.
   2    Copyright (C) 2003, 2005-2007, 2009-2024 Free Software Foundation, Inc.
   3    Written by Bruno Haible <bruno@clisp.org>, 2003.
   4
   5    This program is free software: you can redistribute it and/or modify
   6    it under the terms of the GNU General Public License as published by
   7    the Free Software Foundation, either version 3 of the License, or
   8    (at your option) any later version.
   9
  10    This program 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
  13    GNU General Public License for more details.
  14
  15    You should have received a copy of the GNU General Public License
  16    along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
  17
  18 /* Dependencies:
  19    relocwrapper
  20     -> progname
  21     -> progreloc
  22        -> stat
  23           -> filename
  24           -> pathmax
  25           -> verify
  26        -> areadlink
  27           -> careadlinkat
  28              -> allocator
  29           -> readlink
  30              -> stat
  31        -> canonicalize-lgpl
  32           -> c-bool
  33           -> libc-config
  34           -> errno
  35           -> fcntl-h
  36           -> sys_stat
  37           -> unistd
  38           -> eloop-threshold
  39           -> filename
  40           -> idx
  41           -> intprops
  42           -> scratch_buffer
  43              -> malloc-posix
  44              -> realloc-posix
  45              -> free-posix
  46           -> pathmax
  47           -> mempcpy
  48           -> rawmemchr
  49           -> readlink
  50           -> stat
  51           -> double-slash-root
  52     -> relocatable
  53     -> setenv
  54        -> malloca
  55     -> fprintf-posix [ignore, cut dependency tree here]
  56     -> strerror [ignore, cut dependency tree here]
  57     -> c-ctype
  58
  59    Macros that need to be set while compiling this file:
  60      - ENABLE_RELOCATABLE 1
  61      - INSTALLPREFIX the base installation directory
  62      - INSTALLDIR the directory into which this program is installed
  63      - LIBPATHVAR the platform dependent runtime library path variable
  64      - LIBDIRS a comma-terminated list of strings representing the list of
  65        directories that contain the libraries at installation time
  66
  67    We don't want to internationalize this wrapper because then it would
  68    depend on libintl and therefore need relocation itself.  So use only
  69    libc functions, no gettext(), no error(), no xmalloc(), no xsetenv().
  70  */
  71
  72 #define _GL_USE_STDLIB_ALLOC 1
  73 #include <config.h>
  74
  75 #include <stdio.h>
  76 #include <stdlib.h>
  77 #include <string.h>
  78 #include <unistd.h>
  79 #include <errno.h>
  80
  81 #include "progname.h"
  82 #include "relocatable.h"
  83 #include "c-ctype.h"
  84
  85 /* Use the system functions, not the gnulib overrides in this file.  */
  86 #undef fprintf
  87 #undef strerror
  88
  89 /* Return a copy of the filename, with an extra ".bin" at the end.
  90    More generally, it replaces "${EXEEXT}" at the end with ".bin${EXEEXT}".  */
  91 static char *
  92 add_dotbin (const char *filename)
  93 {
  94   size_t filename_len = strlen (filename);
  95   char *result = (char *) malloc (filename_len + 4 + 1);
  96
  97   if (result != NULL)
  98     {
  99       if (sizeof (EXEEXT) > sizeof (""))
 100         {
 101           /* EXEEXT handling.  */
 102           const size_t exeext_len = sizeof (EXEEXT) - sizeof ("");
 103           static const char exeext[] = EXEEXT;
 104           if (filename_len > exeext_len)
 105             {
 106               /* Compare using an inlined copy of c_strncasecmp(), because
 107                  the filenames may have undergone a case conversion since
 108                  they were packaged.  In other words, EXEEXT may be ".exe"
 109                  on one system and ".EXE" on another.  */
 110               const char *s1 = filename + filename_len - exeext_len;
 111               const char *s2 = exeext;
 112               for (; *s1 != '\0'; s1++, s2++)
 113                 {
 114                   unsigned char c1 = *s1;
 115                   unsigned char c2 = *s2;
 116                   if (c_tolower (c1) != c_tolower (c2))
 117                     goto simple_append;
 118                 }
 119               /* Insert ".bin" before EXEEXT or its equivalent.  */
 120               memcpy (result, filename, filename_len - exeext_len);
 121               memcpy (result + filename_len - exeext_len, ".bin", 4);
 122               memcpy (result + filename_len - exeext_len + 4,
 123                       filename + filename_len - exeext_len,
 124                       exeext_len + 1);
 125               return result;
 126             }
 127         }
 128      simple_append:
 129       /* Simply append ".bin".  */
 130       memcpy (result, filename, filename_len);
 131       memcpy (result + filename_len, ".bin", 4 + 1);
 132       return result;
 133     }
 134   else
 135     {
 136       fprintf (stderr, "%s: %s\n", program_name, "memory exhausted");
 137       exit (1);
 138     }
 139 }
 140
 141 /* List of directories that contain the libraries.  */
 142 static const char *libdirs[] = { LIBDIRS NULL };
 143 /* Verify that at least one directory is given.  */
 144 static_assert (sizeof (libdirs) / sizeof (libdirs[0]) > 1);
 145
 146 /* Relocate the list of directories that contain the libraries.  */
 147 static void
 148 relocate_libdirs ()
 149 {
 150   size_t i;
 151
 152   for (i = 0; i < sizeof (libdirs) / sizeof (libdirs[0]) - 1; i++)
 153     libdirs[i] = relocate (libdirs[i]);
 154 }
 155
 156 /* Activate the list of directories in the LIBPATHVAR.  */
 157 static void
 158 activate_libdirs ()
 159 {
 160   const char *old_value;
 161   size_t total;
 162   size_t i;
 163   char *value;
 164   char *p;
 165
 166   old_value = getenv (LIBPATHVAR);
 167   if (old_value == NULL)
 168     old_value = "";
 169
 170   total = 0;
 171   for (i = 0; i < sizeof (libdirs) / sizeof (libdirs[0]) - 1; i++)
 172     total += strlen (libdirs[i]) + 1;
 173   total += strlen (old_value) + 1;
 174
 175   value = (char *) malloc (total);
 176   if (value == NULL)
 177     {
 178       fprintf (stderr, "%s: %s\n", program_name, "memory exhausted");
 179       exit (1);
 180     }
 181   p = value;
 182   for (i = 0; i < sizeof (libdirs) / sizeof (libdirs[0]) - 1; i++)
 183     {
 184       size_t len = strlen (libdirs[i]);
 185       memcpy (p, libdirs[i], len);
 186       p += len;
 187       *p++ = ':';
 188     }
 189   if (old_value[0] != '\0')
 190     strcpy (p, old_value);
 191   else
 192     p[-1] = '\0';
 193
 194   if (setenv (LIBPATHVAR, value, 1) < 0)
 195     {
 196       fprintf (stderr, "%s: %s\n", program_name, "memory exhausted");
 197       exit (1);
 198     }
 199 }
 200
 201 int
 202 main (int argc, char *argv[])
 203 {
 204   char *full_program_name;
 205
 206   /* Set the program name and perform preparations for
 207      get_full_program_name() and relocate().  */
 208   set_program_name_and_installdir (argv[0], INSTALLPREFIX, INSTALLDIR);
 209
 210   /* Get the full program path.  (Important if accessed through a symlink.)  */
 211   full_program_name = get_full_program_name ();
 212   if (full_program_name == NULL)
 213     full_program_name = argv[0];
 214
 215   /* Invoke the real program, with suffix ".bin".  */
 216   argv[0] = add_dotbin (full_program_name);
 217   relocate_libdirs ();
 218   activate_libdirs ();
 219   execv (argv[0], argv);
 220   fprintf (stderr, "%s: could not execute %s: %s\n",
 221            program_name, argv[0], strerror (errno));
 222   exit (127);
 223 }