djgpp/subpipe.c

   1 /* Subprocesses with pipes.
   2
   3    Copyright (C) 2005, 2006 Free Software Foundation, Inc.
   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 2, or (at your option)
   8    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, write to the Free Software Foundation,
  17    Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
  18
  19 /* Written by Juan Manuel Guerrero <juan.guerrero@gmx.de>. */
  20
  21
  22 #include <config.h>
  23
  24 #include "subpipe.h"
  25
  26 #include <errno.h>
  27 #include <fcntl.h>
  28 #include <sys/stat.h>
  29 #include <process.h>
  30 #include <signal.h>
  31 #include <stdio.h>
  32 #include <stdlib.h>
  33 #include <string.h>
  34 #include <unistd.h>
  35 #include "xalloc.h"
  36
  37
  38 #ifndef STDIN_FILENO
  39 # define STDIN_FILENO 0
  40 #endif
  41 #ifndef STDOUT_FILENO
  42 # define STDOUT_FILENO 1
  43 #endif
  44
  45
  46 #include "error.h"
  47
  48 #include "gettext.h"
  49 #define _(Msgid)  gettext (Msgid)
  50
  51
  52 /* Initialize this module. */
  53
  54
  55 static int old_stdin;
  56 static int old_stdout;
  57 static char **arguments;
  58 static char tmp_file_name[2][L_tmpnam];
  59
  60 #define remove_tmp_file(fd, name)                                     \
  61   do {                                                                \
  62     close ((fd));                                                     \
  63     if (unlink ((name)))                                              \
  64       error (EXIT_FAILURE, 0, _("removing of `%s' failed"), (name));  \
  65   } while (0)
  66
  67
  68 void
  69 init_subpipe(void)
  70 {
  71   int fd;
  72
  73   strcpy(tmp_file_name[0], "/dev/env/TMPDIR/bnXXXXXX");
  74   fd = mkstemp(tmp_file_name[0]);
  75   if (fd < 0)
  76     error(EXIT_FAILURE, 0, _("creation of a temporary file failed"));
  77   close (fd);
  78
  79   strcpy(tmp_file_name[1], "/dev/env/TMPDIR/bnXXXXXX");
  80   fd = mkstemp(tmp_file_name[1]);
  81   if (fd < 0)
  82     error(EXIT_FAILURE, 0, _("creation of a temporary file failed"));
  83   close (fd);
  84 }
  85
  86
  87 /* Create a subprocess that is run as a filter.  ARGV is the
  88    NULL-terminated argument vector for the subprocess.  Store read and
  89    write file descriptors for communication with the subprocess into
  90    FD[0] and FD[1]: input meant for the process can be written into
  91    FD[0], and output from the process can be read from FD[1].  Return
  92    the subprocess id.
  93
  94    Because DOS has neither fork nor pipe functionality to run the subprocess
  95    as a filter, the filter is reproduced using temporary files. First bison's
  96    stdout is redirected to a temporary file. After bison has produced all of
  97    is output, this file is closed and connected to m4's stdin. All m4's output
  98    is redirected from m4's stdout to a second temporary file and reopened as
  99    bison's stdin. */
 100
 101 pid_t
 102 create_subpipe(char const *const *argv, int fd[2])
 103 {
 104   int argc;
 105   int from_in_fd;  /* pipe from bison to m4. */
 106   pid_t pid;
 107
 108
 109   pid = getpid();
 110
 111   /*
 112    *  Save original stdin and stdout
 113    *  for later restauration.
 114    */
 115   old_stdin = dup(STDIN_FILENO);
 116   if (old_stdin < 0)
 117     error(EXIT_FAILURE, 0, _("saving stdin failed"));
 118
 119   old_stdout = dup(STDOUT_FILENO);
 120   if (old_stdout < 0)
 121     error(EXIT_FAILURE, 0, _("saving stdout failed"));
 122
 123   /*
 124    *  Save argv for later use.
 125    */
 126   for (argc = 0; argv[argc]; argc++)
 127     ;
 128   argc++;
 129   arguments = xmalloc(argc * sizeof(arguments[0]));
 130   for (argc = 0; argv[argc]; argc++)
 131   {
 132     arguments[argc] = xmalloc((strlen(argv[argc]) + 1) * sizeof(arguments[0][0]));
 133     strcpy(arguments[argc], argv[argc]);
 134   }
 135   arguments[argc] = NULL;
 136
 137   /*
 138    *  All bison's output will be gathered in this temporary file
 139    *  and will be redirected to m4's stdin.
 140    */
 141   from_in_fd = open(tmp_file_name[0], O_WRONLY | O_CREAT | O_TRUNC, S_IWUSR);
 142   if (from_in_fd < 0)
 143     error(EXIT_FAILURE, 0, _("opening of tmpfile failed"));
 144   if (dup2(from_in_fd, STDOUT_FILENO) < 0)
 145   {
 146     remove_tmp_file(from_in_fd, tmp_file_name[0]);
 147     error(EXIT_FAILURE, 0, _("redirecting bison's stdout to the temporary file failed"));
 148   }
 149   close(from_in_fd);
 150
 151
 152   fd[0] = STDOUT_FILENO;
 153   return pid;
 154 }
 155
 156
 157 /* A signal handler that just records that a signal has happened. */
 158 static int child_interrupted;
 159
 160 static void
 161 signal_catcher(int signo)
 162 {
 163   child_interrupted++;
 164 }
 165
 166
 167 void
 168 end_of_output_subpipe(pid_t pid, int fd[2])
 169 {
 170   char *program;
 171   int from_out_fd = open(tmp_file_name[0], O_RDONLY, S_IRUSR);                   /* pipe from bison to m4. */
 172   int to_in_fd = open(tmp_file_name[1], O_WRONLY | O_CREAT | O_TRUNC, S_IWUSR);  /* pipe from m4 to bison. */
 173   int status;
 174   void (*previous_handler)(int);
 175
 176
 177   program = strrchr(arguments[0], '/');
 178   if (program)
 179     program++;
 180   else
 181     program = arguments[0];
 182
 183   /*
 184    *  Redirect bison's output to m4's stdin.
 185    */
 186   if (from_out_fd < 0)
 187     error(EXIT_FAILURE, 0, _("opening of tmpfile failed"));
 188   if (dup2(from_out_fd, STDIN_FILENO) < 0)
 189   {
 190     remove_tmp_file(from_out_fd, tmp_file_name[0]);
 191     error(EXIT_FAILURE, 0, _("redirecting m4's stdin from the temporary file failed"));
 192   }
 193   close(from_out_fd);
 194
 195   /*
 196    *  All m4's output will be gathered in this temporary file
 197    *  and will be redirected to bison's stdin.
 198    */
 199   if (to_in_fd < 0)
 200   {
 201     remove_tmp_file(STDIN_FILENO, tmp_file_name[0]);
 202     error(EXIT_FAILURE, 0, _("opening of a temporary file failed"));
 203   }
 204   if (dup2(to_in_fd, STDOUT_FILENO) < 0)
 205   {
 206     remove_tmp_file(STDIN_FILENO, tmp_file_name[0]);
 207     remove_tmp_file(to_in_fd, tmp_file_name[1]);
 208     error(EXIT_FAILURE, 0, _("redirecting m4's stdout to a temporary file failed"));
 209   }
 210   close(to_in_fd);
 211
 212   /*
 213    *  Run m4.
 214    */
 215   child_interrupted = 0;
 216   errno = 0;
 217   previous_handler = signal(SIGINT, signal_catcher);
 218   status = spawnvp(P_WAIT, program, arguments);
 219   signal(SIGINT, previous_handler);
 220   if (child_interrupted)
 221   {
 222     remove_tmp_file(STDIN_FILENO, tmp_file_name[0]);
 223     remove_tmp_file(STDOUT_FILENO, tmp_file_name[1]);
 224     error(EXIT_FAILURE, 0, _("subsidiary program `%s' interrupted"), program);
 225   }
 226   if (status)
 227   {
 228     remove_tmp_file(STDIN_FILENO, tmp_file_name[0]);
 229     remove_tmp_file(STDOUT_FILENO, tmp_file_name[1]);
 230     error(EXIT_FAILURE, 0, _(errno == ENOENT
 231                              ? "subsidiary program `%s' not found"
 232                              : status < 1
 233                              ? "subsidiary program `%s' failed"
 234                              : "subsidiary program `%s' failed (status=%i, errno=%i)"), program, status, errno);
 235   }
 236
 237
 238   /*
 239    *  Redirect m4's output to bison's stdin.
 240    */
 241   if (dup2(old_stdout, STDOUT_FILENO) < 0)
 242     error(EXIT_FAILURE, 0, "restore of bison's stdout failed");
 243   close(old_stdout);
 244   to_in_fd = open(tmp_file_name[1], O_RDONLY, S_IRUSR);  /* pipe from m4 to bison. */
 245   if (to_in_fd < 0)
 246   {
 247     remove_tmp_file(STDIN_FILENO, tmp_file_name[0]);
 248     error(EXIT_FAILURE, 0, _("opening of tmpfile failed"));
 249   }
 250   if (dup2(to_in_fd, STDIN_FILENO) < 0)
 251   {
 252     remove_tmp_file(STDIN_FILENO, tmp_file_name[0]);
 253     remove_tmp_file(to_in_fd, tmp_file_name[1]);
 254     error(EXIT_FAILURE, -1, "dup2");
 255     error(EXIT_FAILURE, 0, _("redirecting bison's stdin from the temporary file failed"));
 256   }
 257   close(to_in_fd);
 258
 259
 260   fd[1] = STDIN_FILENO;
 261 }
 262
 263
 264 /* Free resources, unlink temporary files and restore stdin and stdout. */
 265
 266 void
 267 reap_subpipe(pid_t pid, char const *program)
 268 {
 269   int argc;
 270
 271   for (argc = 0; arguments[argc]; argc++)
 272     free(arguments[argc]);
 273   free(arguments);
 274
 275   if (unlink(tmp_file_name[0]))
 276     error(EXIT_FAILURE, 0, _("removing of `%s' failed"), tmp_file_name[0]);
 277   if (unlink(tmp_file_name[1]))
 278     error(EXIT_FAILURE, 0, _("removing of `%s' failed"), tmp_file_name[1]);
 279
 280   if (dup2(old_stdin, STDIN_FILENO) < 0)
 281     error(EXIT_FAILURE, 0, "restore of bison's stdin failed");
 282   close(old_stdin);
 283 }