libgfortran/runtime/main.c

   1 /* Copyright (C) 2002-2003, 2005, 2007, 2009, 2011
   2    Free Software Foundation, Inc.
   3    Contributed by Andy Vaught and Paul Brook <paul@nowt.org>
   4
   5 This file is part of the GNU Fortran runtime library (libgfortran).
   6
   7 Libgfortran is free software; you can redistribute it and/or modify
   8 it under the terms of the GNU General Public License as published by
   9 the Free Software Foundation; either version 3, or (at your option)
  10 any later version.
  11
  12 Libgfortran is distributed in the hope that it will be useful,
  13 but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 GNU General Public License for more details.
  16
  17 Under Section 7 of GPL version 3, you are granted additional
  18 permissions described in the GCC Runtime Library Exception, version
  19 3.1, as published by the Free Software Foundation.
  20
  21 You should have received a copy of the GNU General Public License and
  22 a copy of the GCC Runtime Library Exception along with this program;
  23 see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  24 <http://www.gnu.org/licenses/>.  */
  25
  26 #include "libgfortran.h"
  27 #include <stdlib.h>
  28 #include <string.h>
  29 #include <limits.h>
  30
  31
  32 #ifdef HAVE_UNISTD_H
  33 #include <unistd.h>
  34 #endif
  35
  36 /* Stupid function to be sure the constructor is always linked in, even
  37    in the case of static linking.  See PR libfortran/22298 for details.  */
  38 void
  39 stupid_function_name_for_static_linking (void)
  40 {
  41   return;
  42 }
  43
  44 /* This will be 0 for little-endian
  45    machines and 1 for big-endian machines.  */
  46 int big_endian = 0;
  47
  48
  49 /* Figure out endianness for this machine.  */
  50
  51 static void
  52 determine_endianness (void)
  53 {
  54   union
  55   {
  56     GFC_LOGICAL_8 l8;
  57     GFC_LOGICAL_4 l4[2];
  58   } u;
  59
  60   u.l8 = 1;
  61   if (u.l4[0])
  62     big_endian = 0;
  63   else if (u.l4[1])
  64     big_endian = 1;
  65   else
  66     runtime_error ("Unable to determine machine endianness");
  67 }
  68
  69
  70 static int argc_save;
  71 static char **argv_save;
  72
  73 static const char *exe_path;
  74 static int please_free_exe_path_when_done;
  75
  76 /* Save the path under which the program was called, for use in the
  77    backtrace routines.  */
  78 void
  79 store_exe_path (const char * argv0)
  80 {
  81 #ifndef PATH_MAX
  82 #define PATH_MAX 1024
  83 #endif
  84
  85 #ifndef DIR_SEPARATOR
  86 #define DIR_SEPARATOR '/'
  87 #endif
  88
  89   char buf[PATH_MAX], *cwd, *path;
  90
  91   /* This can only happen if store_exe_path is called multiple times.  */
  92   if (please_free_exe_path_when_done)
  93     free ((char *) exe_path);
  94
  95   /* Reading the /proc/self/exe symlink is Linux-specific(?), but if
  96      it works it gives the correct answer.  */
  97 #ifdef HAVE_READLINK
  98   int len;
  99   if ((len = readlink ("/proc/self/exe", buf, sizeof (buf) - 1)) != -1)
 100     {
 101       buf[len] = '\0';
 102       exe_path = strdup (buf);
 103       please_free_exe_path_when_done = 1;
 104       return;
 105     }
 106 #endif
 107
 108   /* On the simulator argv is not set.  */
 109   if (argv0 == NULL || argv0[0] == '/')
 110     {
 111       exe_path = argv0;
 112       please_free_exe_path_when_done = 0;
 113       return;
 114     }
 115
 116   memset (buf, 0, sizeof (buf));
 117 #ifdef HAVE_GETCWD
 118   cwd = getcwd (buf, sizeof (buf));
 119 #else
 120   cwd = "";
 121 #endif
 122
 123   /* exe_path will be cwd + "/" + argv[0] + "\0".  This will not work
 124      if the executable is not in the cwd, but at this point we're out
 125      of better ideas.  */
 126   size_t pathlen = strlen (cwd) + 1 + strlen (argv0) + 1;
 127   path = malloc (pathlen);
 128   snprintf (path, pathlen, "%s%c%s", cwd, DIR_SEPARATOR, argv0);
 129   exe_path = path;
 130   please_free_exe_path_when_done = 1;
 131 }
 132
 133
 134 /* Return the full path of the executable.  */
 135 char *
 136 full_exe_path (void)
 137 {
 138   return (char *) exe_path;
 139 }
 140
 141
 142 char *addr2line_path;
 143
 144 /* Find addr2line and store the path.  */
 145
 146 void
 147 find_addr2line (void)
 148 {
 149 #ifdef HAVE_ACCESS
 150 #define A2L_LEN 10
 151   char *path = getenv ("PATH");
 152   size_t n = strlen (path);
 153   char ap[n + 1 + A2L_LEN];
 154   size_t ai = 0;
 155   for (size_t i = 0; i < n; i++)
 156     {
 157       if (path[i] != ':')
 158         ap[ai++] = path[i];
 159       else
 160         {
 161           ap[ai++] = '/';
 162           memcpy (ap + ai, "addr2line", A2L_LEN);
 163           if (access (ap, R_OK|X_OK) == 0)
 164             {
 165               addr2line_path = strdup (ap);
 166               return;
 167             }
 168           else
 169             ai = 0;
 170         }
 171     }
 172 #endif
 173 }
 174
 175
 176 /* Set the saved values of the command line arguments.  */
 177
 178 void
 179 set_args (int argc, char **argv)
 180 {
 181   argc_save = argc;
 182   argv_save = argv;
 183   store_exe_path (argv[0]);
 184 }
 185 iexport(set_args);
 186
 187
 188 /* Retrieve the saved values of the command line arguments.  */
 189
 190 void
 191 get_args (int *argc, char ***argv)
 192 {
 193   *argc = argc_save;
 194   *argv = argv_save;
 195 }
 196
 197
 198 /* Initialize the runtime library.  */
 199
 200 static void __attribute__((constructor))
 201 init (void)
 202 {
 203   /* Figure out the machine endianness.  */
 204   determine_endianness ();
 205
 206   /* Must be first */
 207   init_variables ();
 208
 209   init_units ();
 210   set_fpu ();
 211   init_compile_options ();
 212
 213 #ifdef DEBUG
 214   /* Check for special command lines.  */
 215
 216   if (argc > 1 && strcmp (argv[1], "--help") == 0)
 217     show_variables ();
 218
 219   /* if (argc > 1 && strcmp(argv[1], "--resume") == 0) resume();  */
 220 #endif
 221
 222   if (options.backtrace == 1)
 223     find_addr2line ();
 224
 225   random_seed_i4 (NULL, NULL, NULL);
 226 }
 227
 228
 229 /* Cleanup the runtime library.  */
 230
 231 static void __attribute__((destructor))
 232 cleanup (void)
 233 {
 234   close_units ();
 235
 236   if (please_free_exe_path_when_done)
 237     free ((char *) exe_path);
 238
 239   free (addr2line_path);
 240 }