lib/relocwrapper.c

   1 /* Relocating wrapper program.
   2    Copyright (C) 2003, 2005-2007, 2009-2018 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        -> areadlink
  23           -> careadlinkat
  24              -> allocator
  25           -> readlink
  26              -> stat
  27                 -> dosname
  28                 -> pathmax
  29                 -> verify
  30        -> canonicalize-lgpl
  31           -> malloca
  32           -> lstat
  33           -> readlink
  34     -> relocatable
  35     -> setenv
  36        -> malloca
  37     -> fprintf-posix [ignore, cut dependency tree here]
  38     -> strerror [ignore, cut dependency tree here]
  39     -> c-ctype
  40
  41    Macros that need to be set while compiling this file:
  42      - ENABLE_RELOCATABLE 1
  43      - INSTALLPREFIX the base installation directory
  44      - INSTALLDIR the directory into which this program is installed
  45      - LIBPATHVAR the platform dependent runtime library path variable
  46      - LIBDIRS a comma-terminated list of strings representing the list of
  47        directories that contain the libraries at installation time
  48
  49    We don't want to internationalize this wrapper because then it would
  50    depend on libintl and therefore need relocation itself.  So use only
  51    libc functions, no gettext(), no error(), no xmalloc(), no xsetenv().
  52  */
  53
  54 #define _GL_USE_STDLIB_ALLOC 1
  55 #include <config.h>
  56
  57 #include <stdio.h>
  58 #include <stdlib.h>
  59 #include <string.h>
  60 #include <unistd.h>
  61 #include <errno.h>
  62
  63 #include "progname.h"
  64 #include "relocatable.h"
  65 #include "c-ctype.h"
  66 #include "verify.h"
  67
  68 /* Use the system functions, not the gnulib overrides in this file.  */
  69 #undef fprintf
  70 #undef strerror
  71
  72 /* Return a copy of the filename, with an extra ".bin" at the end.
  73    More generally, it replaces "${EXEEXT}" at the end with ".bin${EXEEXT}".  */
  74 static char *
  75 add_dotbin (const char *filename)
  76 {
  77   size_t filename_len = strlen (filename);
  78   char *result = (char *) malloc (filename_len + 4 + 1);
  79
  80   if (result != NULL)
  81     {
  82       if (sizeof (EXEEXT) > sizeof (""))
  83         {
  84           /* EXEEXT handling.  */
  85           const size_t exeext_len = sizeof (EXEEXT) - sizeof ("");
  86           static const char exeext[] = EXEEXT;
  87           if (filename_len > exeext_len)
  88             {
  89               /* Compare using an inlined copy of c_strncasecmp(), because
  90                  the filenames may have undergone a case conversion since
  91                  they were packaged.  In other words, EXEEXT may be ".exe"
  92                  on one system and ".EXE" on another.  */
  93               const char *s1 = filename + filename_len - exeext_len;
  94               const char *s2 = exeext;
  95               for (; *s1 != '\0'; s1++, s2++)
  96                 {
  97                   unsigned char c1 = *s1;
  98                   unsigned char c2 = *s2;
  99                   if (c_tolower (c1) != c_tolower (c2))
 100                     goto simple_append;
 101                 }
 102               /* Insert ".bin" before EXEEXT or its equivalent.  */
 103               memcpy (result, filename, filename_len - exeext_len);
 104               memcpy (result + filename_len - exeext_len, ".bin", 4);
 105               memcpy (result + filename_len - exeext_len + 4,
 106                       filename + filename_len - exeext_len,
 107                       exeext_len + 1);
 108               return result;
 109             }
 110         }
 111      simple_append:
 112       /* Simply append ".bin".  */
 113       memcpy (result, filename, filename_len);
 114       memcpy (result + filename_len, ".bin", 4 + 1);
 115       return result;
 116     }
 117   else
 118     {
 119       fprintf (stderr, "%s: %s\n", program_name, "memory exhausted");
 120       exit (1);
 121     }
 122 }
 123
 124 /* List of directories that contain the libraries.  */
 125 static const char *libdirs[] = { LIBDIRS NULL };
 126 /* Verify that at least one directory is given.  */
 127 verify (sizeof (libdirs) / sizeof (libdirs[0]) > 1);
 128
 129 /* Relocate the list of directories that contain the libraries.  */
 130 static void
 131 relocate_libdirs ()
 132 {
 133   size_t i;
 134
 135   for (i = 0; i < sizeof (libdirs) / sizeof (libdirs[0]) - 1; i++)
 136     libdirs[i] = relocate (libdirs[i]);
 137 }
 138
 139 /* Activate the list of directories in the LIBPATHVAR.  */
 140 static void
 141 activate_libdirs ()
 142 {
 143   const char *old_value;
 144   size_t total;
 145   size_t i;
 146   char *value;
 147   char *p;
 148
 149   old_value = getenv (LIBPATHVAR);
 150   if (old_value == NULL)
 151     old_value = "";
 152
 153   total = 0;
 154   for (i = 0; i < sizeof (libdirs) / sizeof (libdirs[0]) - 1; i++)
 155     total += strlen (libdirs[i]) + 1;
 156   total += strlen (old_value) + 1;
 157
 158   value = (char *) malloc (total);
 159   if (value == NULL)
 160     {
 161       fprintf (stderr, "%s: %s\n", program_name, "memory exhausted");
 162       exit (1);
 163     }
 164   p = value;
 165   for (i = 0; i < sizeof (libdirs) / sizeof (libdirs[0]) - 1; i++)
 166     {
 167       size_t len = strlen (libdirs[i]);
 168       memcpy (p, libdirs[i], len);
 169       p += len;
 170       *p++ = ':';
 171     }
 172   if (old_value[0] != '\0')
 173     strcpy (p, old_value);
 174   else
 175     p[-1] = '\0';
 176
 177   if (setenv (LIBPATHVAR, value, 1) < 0)
 178     {
 179       fprintf (stderr, "%s: %s\n", program_name, "memory exhausted");
 180       exit (1);
 181     }
 182 }
 183
 184 int
 185 main (int argc, char *argv[])
 186 {
 187   char *full_program_name;
 188
 189   /* Set the program name and perform preparations for
 190      get_full_program_name() and relocate().  */
 191   set_program_name_and_installdir (argv[0], INSTALLPREFIX, INSTALLDIR);
 192
 193   /* Get the full program path.  (Important if accessed through a symlink.)  */
 194   full_program_name = get_full_program_name ();
 195   if (full_program_name == NULL)
 196     full_program_name = argv[0];
 197
 198   /* Invoke the real program, with suffix ".bin".  */
 199   argv[0] = add_dotbin (full_program_name);
 200   relocate_libdirs ();
 201   activate_libdirs ();
 202   execv (argv[0], argv);
 203   fprintf (stderr, "%s: could not execute %s: %s\n",
 204            program_name, argv[0], strerror (errno));
 205   exit (127);
 206 }