libgfortran/runtime/main.c

   1 /* Copyright (C) 2002-2015 Free Software Foundation, Inc.
   2    Contributed by Andy Vaught and Paul Brook <paul@nowt.org>
   3
   4 This file is part of the GNU Fortran runtime library (libgfortran).
   5
   6 Libgfortran is free software; you can redistribute it and/or modify
   7 it under the terms of the GNU General Public License as published by
   8 the Free Software Foundation; either version 3, or (at your option)
   9 any later version.
  10
  11 Libgfortran is distributed in the hope that it will be useful,
  12 but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 GNU General Public License for more details.
  15
  16 Under Section 7 of GPL version 3, you are granted additional
  17 permissions described in the GCC Runtime Library Exception, version
  18 3.1, as published by the Free Software Foundation.
  19
  20 You should have received a copy of the GNU General Public License and
  21 a copy of the GCC Runtime Library Exception along with this program;
  22 see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  23 <http://www.gnu.org/licenses/>.  */
  24
  25 #include "libgfortran.h"
  26 #include <stdlib.h>
  27 #include <string.h>
  28 #include <limits.h>
  29 #include <errno.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 bool 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 DIR_SEPARATOR
  82 #define DIR_SEPARATOR '/'
  83 #endif
  84
  85   char *cwd, *path;
  86
  87   /* This can only happen if store_exe_path is called multiple times.  */
  88   if (please_free_exe_path_when_done)
  89     free ((char *) exe_path);
  90
  91   /* Reading the /proc/self/exe symlink is Linux-specific(?), but if
  92      it works it gives the correct answer.  */
  93 #ifdef HAVE_READLINK
  94   ssize_t len, psize = 256;
  95   while (1)
  96     {
  97       path = xmalloc (psize);
  98       len = readlink ("/proc/self/exe", path, psize);
  99       if (len < 0)
 100         {
 101           free (path);
 102           break;
 103         }
 104       else if (len < psize)
 105         {
 106           path[len] = '\0';
 107           exe_path = strdup (path);
 108           free (path);
 109           please_free_exe_path_when_done = true;
 110           return;
 111         }
 112       /* The remaining option is len == psize.  */
 113       free (path);
 114       psize *= 4;
 115     }
 116 #endif
 117
 118   /* If the path is absolute or on a simulator where argv is not set.  */
 119 #ifdef __MINGW32__
 120   if (argv0 == NULL
 121       || ('A' <= argv0[0] && argv0[0] <= 'Z' && argv0[1] == ':')
 122       || ('a' <= argv0[0] && argv0[0] <= 'z' && argv0[1] == ':')
 123       || (argv0[0] == '/' && argv0[1] == '/')
 124       || (argv0[0] == '\\' && argv0[1] == '\\'))
 125 #else
 126   if (argv0 == NULL || argv0[0] == DIR_SEPARATOR)
 127 #endif
 128     {
 129       exe_path = argv0;
 130       please_free_exe_path_when_done = false;
 131       return;
 132     }
 133
 134 #ifdef HAVE_GETCWD
 135   size_t cwdsize = 256;
 136   while (1)
 137     {
 138       cwd = xmalloc (cwdsize);
 139       if (getcwd (cwd, cwdsize))
 140         break;
 141       else if (errno == ERANGE)
 142         {
 143           free (cwd);
 144           cwdsize *= 4;
 145         }
 146       else
 147         {
 148           free (cwd);
 149           cwd = NULL;
 150           break;
 151         }
 152     }
 153 #else
 154   cwd = NULL;
 155 #endif
 156
 157   if (!cwd)
 158     {
 159       exe_path = argv0;
 160       please_free_exe_path_when_done = false;
 161       return;
 162     }
 163
 164   /* exe_path will be cwd + "/" + argv[0] + "\0".  This will not work
 165      if the executable is not in the cwd, but at this point we're out
 166      of better ideas.  */
 167   size_t pathlen = strlen (cwd) + 1 + strlen (argv0) + 1;
 168   path = xmalloc (pathlen);
 169   snprintf (path, pathlen, "%s%c%s", cwd, DIR_SEPARATOR, argv0);
 170   free (cwd);
 171   exe_path = path;
 172   please_free_exe_path_when_done = true;
 173 }
 174
 175
 176 /* Return the full path of the executable.  */
 177 char *
 178 full_exe_path (void)
 179 {
 180   return (char *) exe_path;
 181 }
 182
 183
 184 #ifndef HAVE_STRTOK_R
 185 static char*
 186 gfstrtok_r (char *str, const char *delim,
 187             char **saveptr __attribute__ ((unused)))
 188 {
 189   return strtok (str, delim);
 190 }
 191 #define strtok_r gfstrtok_r
 192 #endif
 193
 194 char *addr2line_path;
 195
 196 /* Find addr2line and store the path.  */
 197
 198 void
 199 find_addr2line (void)
 200 {
 201 #ifdef HAVE_ACCESS
 202 #define A2L_LEN 11
 203   char *path = secure_getenv ("PATH");
 204   if (!path)
 205     return;
 206   char *tp = strdup (path);
 207   if (!tp)
 208     return;
 209   size_t n = strlen (path);
 210   char *ap = xmalloc (n + A2L_LEN);
 211   char *saveptr;
 212   for (char *str = tp;; str = NULL)
 213     {
 214       char *token = strtok_r (str, ":", &saveptr);
 215       if (!token)
 216         break;
 217       size_t toklen = strlen (token);
 218       memcpy (ap, token, toklen);
 219       memcpy (ap + toklen, "/addr2line", A2L_LEN);
 220       if (access (ap, R_OK|X_OK) == 0)
 221         {
 222           addr2line_path = strdup (ap);
 223           break;
 224         }
 225     }
 226   free (tp);
 227   free (ap);
 228 #endif
 229 }
 230
 231
 232 /* Set the saved values of the command line arguments.  */
 233
 234 void
 235 set_args (int argc, char **argv)
 236 {
 237   argc_save = argc;
 238   argv_save = argv;
 239   store_exe_path (argv[0]);
 240 }
 241 iexport(set_args);
 242
 243
 244 /* Retrieve the saved values of the command line arguments.  */
 245
 246 void
 247 get_args (int *argc, char ***argv)
 248 {
 249   *argc = argc_save;
 250   *argv = argv_save;
 251 }
 252
 253
 254 /* Initialize the runtime library.  */
 255
 256 static void __attribute__((constructor))
 257 init (void)
 258 {
 259   /* Figure out the machine endianness.  */
 260   determine_endianness ();
 261
 262   /* Must be first */
 263   init_variables ();
 264
 265   init_units ();
 266   set_fpu ();
 267   init_compile_options ();
 268
 269 #ifdef DEBUG
 270   /* Check for special command lines.  */
 271
 272   if (argc > 1 && strcmp (argv[1], "--help") == 0)
 273     show_variables ();
 274
 275   /* if (argc > 1 && strcmp(argv[1], "--resume") == 0) resume();  */
 276 #endif
 277
 278   if (options.backtrace == 1)
 279     find_addr2line ();
 280
 281   random_seed_i4 (NULL, NULL, NULL);
 282 }
 283
 284
 285 /* Cleanup the runtime library.  */
 286
 287 static void __attribute__((destructor))
 288 cleanup (void)
 289 {
 290   close_units ();
 291
 292   if (please_free_exe_path_when_done)
 293     free ((char *) exe_path);
 294
 295   free (addr2line_path);
 296 }