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 #ifdef HAVE_CONFIG_H
  23 # include <config.h>
  24 #endif
  25
  26 #include "subpipe.h"
  27
  28 #include <errno.h>
  29 #include <fcntl.h>
  30 #include <sys/stat.h>
  31 #include <process.h>
  32 #include <signal.h>
  33 #include <stdio.h>
  34 #include <stdlib.h>
  35 #include <string.h>
  36 #include <unistd.h>
  37 #include "xalloc.h"
  38
  39
  40 #ifndef STDIN_FILENO
  41 # define STDIN_FILENO 0
  42 #endif
  43 #ifndef STDOUT_FILENO
  44 # define STDOUT_FILENO 1
  45 #endif
  46
  47
  48 #include "error.h"
  49
  50 #include "gettext.h"
  51 #define _(Msgid)  gettext (Msgid)
  52
  53
  54 /* Initialize this module. */
  55
  56
  57 static int old_stdin;
  58 static int old_stdout;
  59 static char **arguments;
  60 static char tmp_file_name[2][L_tmpnam];
  61
  62 #define remove_tmp_file(fd, name)                                     \
  63   do {                                                                \
  64     close ((fd));                                                     \
  65     if (unlink ((name)))                                              \
  66       error (EXIT_FAILURE, 0, _("removing of `%s' failed"), (name));  \
  67   } while (0)
  68
  69
  70 void
  71 init_subpipe(void)
  72 {
  73   int fd;
  74
  75   strcpy(tmp_file_name[0], "/dev/env/TMPDIR/bnXXXXXX");
  76   fd = mkstemp(tmp_file_name[0]);
  77   if (fd < 0)
  78     error(EXIT_FAILURE, 0, _("creation of a temporary file failed"));
  79   close (fd);
  80
  81   strcpy(tmp_file_name[1], "/dev/env/TMPDIR/bnXXXXXX");
  82   fd = mkstemp(tmp_file_name[1]);
  83   if (fd < 0)
  84     error(EXIT_FAILURE, 0, _("creation of a temporary file failed"));
  85   close (fd);
  86 }
  87
  88
  89 /* Create a subprocess that is run as a filter.  ARGV is the
  90    NULL-terminated argument vector for the subprocess.  Store read and
  91    write file descriptors for communication with the subprocess into
  92    FD[0] and FD[1]: input meant for the process can be written into
  93    FD[0], and output from the process can be read from FD[1].  Return
  94    the subprocess id.
  95
  96    Because DOS has neither fork nor pipe functionality to run the subprocess
  97    as a filter, the filter is reproduced using temporary files. First bison's
  98    stdout is redirected to a temporary file. After bison has produced all of
  99    is output, this file is closed and connected to m4's stdin. All m4's output
 100    is redirected from m4's stdout to a second temporary file and reopened as
 101    bison's stdin. */
 102
 103 pid_t
 104 create_subpipe(char const *const *argv, int fd[2])
 105 {
 106   int argc;
 107   int from_in_fd;  /* pipe from bison to m4. */
 108   pid_t pid;
 109
 110
 111   pid = getpid();
 112
 113   /*
 114    *  Save original stdin and stdout
 115    *  for later restauration.
 116    */
 117   old_stdin = dup(STDIN_FILENO);
 118   if (old_stdin < 0)
 119     error(EXIT_FAILURE, 0, _("saving stdin failed"));
 120
 121   old_stdout = dup(STDOUT_FILENO);
 122   if (old_stdout < 0)
 123     error(EXIT_FAILURE, 0, _("saving stdout failed"));
 124
 125   /*
 126    *  Save argv for later use.
 127    */
 128   for (argc = 0; argv[argc]; argc++)
 129     ;
 130   argc++;
 131   arguments = xmalloc(argc * sizeof(arguments[0]));
 132   for (argc = 0; argv[argc]; argc++)
 133   {
 134     arguments[argc] = xmalloc((strlen(argv[argc]) + 1) * sizeof(arguments[0][0]));
 135     strcpy(arguments[argc], argv[argc]);
 136   }
 137   arguments[argc] = NULL;
 138
 139   /*
 140    *  All bison's output will be gathered in this temporary file
 141    *  and will be redirected to m4's stdin.
 142    */
 143   from_in_fd = open(tmp_file_name[0], O_WRONLY | O_CREAT | O_TRUNC, S_IWUSR);
 144   if (from_in_fd < 0)
 145     error(EXIT_FAILURE, 0, _("opening of tmpfile failed"));
 146   if (dup2(from_in_fd, STDOUT_FILENO) < 0)
 147   {
 148     remove_tmp_file(from_in_fd, tmp_file_name[0]);
 149     error(EXIT_FAILURE, 0, _("redirecting bison's stdout to the temporary file failed"));
 150   }
 151   close(from_in_fd);
 152
 153
 154   fd[0] = STDOUT_FILENO;
 155   return pid;
 156 }
 157
 158
 159 /* A signal handler that just records that a signal has happened. */
 160 static int child_interrupted;
 161
 162 static void
 163 signal_catcher(int signo)
 164 {
 165   child_interrupted++;
 166 }
 167
 168
 169 void
 170 end_of_output_subpipe(pid_t pid, int fd[2])
 171 {
 172   char *program;
 173   int from_out_fd = open(tmp_file_name[0], O_RDONLY, S_IRUSR);                   /* pipe from bison to m4. */
 174   int to_in_fd = open(tmp_file_name[1], O_WRONLY | O_CREAT | O_TRUNC, S_IWUSR);  /* pipe from m4 to bison. */
 175   int status;
 176   void (*previous_handler)(int);
 177
 178
 179   program = strrchr(arguments[0], '/');
 180   if (program)
 181     program++;
 182   else
 183     program = arguments[0];
 184
 185   /*
 186    *  Redirect bison's output to m4's stdin.
 187    */
 188   if (from_out_fd < 0)
 189     error(EXIT_FAILURE, 0, _("opening of tmpfile failed"));
 190   if (dup2(from_out_fd, STDIN_FILENO) < 0)
 191   {
 192     remove_tmp_file(from_out_fd, tmp_file_name[0]);
 193     error(EXIT_FAILURE, 0, _("redirecting m4's stdin from the temporary file failed"));
 194   }
 195   close(from_out_fd);
 196
 197   /*
 198    *  All m4's output will be gathered in this temporary file
 199    *  and will be redirected to bison's stdin.
 200    */
 201   if (to_in_fd < 0)
 202   {
 203     remove_tmp_file(STDIN_FILENO, tmp_file_name[0]);
 204     error(EXIT_FAILURE, 0, _("opening of a temporary file failed"));
 205   }
 206   if (dup2(to_in_fd, STDOUT_FILENO) < 0)
 207   {
 208     remove_tmp_file(STDIN_FILENO, tmp_file_name[0]);
 209     remove_tmp_file(to_in_fd, tmp_file_name[1]);
 210     error(EXIT_FAILURE, 0, _("redirecting m4's stdout to a temporary file failed"));
 211   }
 212   close(to_in_fd);
 213
 214   /*
 215    *  Run m4.
 216    */
 217   child_interrupted = 0;
 218   errno = 0;
 219   previous_handler = signal(SIGINT, signal_catcher);
 220   status = spawnvp(P_WAIT, program, arguments);
 221   signal(SIGINT, previous_handler);
 222   if (child_interrupted)
 223   {
 224     remove_tmp_file(STDIN_FILENO, tmp_file_name[0]);
 225     remove_tmp_file(STDOUT_FILENO, tmp_file_name[1]);
 226     error(EXIT_FAILURE, 0, _("subsidiary program `%s' interrupted"), program);
 227   }
 228   if (status)
 229   {
 230     remove_tmp_file(STDIN_FILENO, tmp_file_name[0]);
 231     remove_tmp_file(STDOUT_FILENO, tmp_file_name[1]);
 232     error(EXIT_FAILURE, 0, _(errno == ENOENT
 233                              ? "subsidiary program `%s' not found"
 234                              : status < 1
 235                              ? "subsidiary program `%s' failed"
 236                              : "subsidiary program `%s' failed (status=%i, errno=%i)"), program, status, errno);
 237   }
 238
 239
 240   /*
 241    *  Redirect m4's output to bison's stdin.
 242    */
 243   if (dup2(old_stdout, STDOUT_FILENO) < 0)
 244     error(EXIT_FAILURE, 0, "restore of bison's stdout failed");
 245   close(old_stdout);
 246   to_in_fd = open(tmp_file_name[1], O_RDONLY, S_IRUSR);  /* pipe from m4 to bison. */
 247   if (to_in_fd < 0)
 248   {
 249     remove_tmp_file(STDIN_FILENO, tmp_file_name[0]);
 250     error(EXIT_FAILURE, 0, _("opening of tmpfile failed"));
 251   }
 252   if (dup2(to_in_fd, STDIN_FILENO) < 0)
 253   {
 254     remove_tmp_file(STDIN_FILENO, tmp_file_name[0]);
 255     remove_tmp_file(to_in_fd, tmp_file_name[1]);
 256     error(EXIT_FAILURE, -1, "dup2");
 257     error(EXIT_FAILURE, 0, _("redirecting bison's stdin from the temporary file failed"));
 258   }
 259   close(to_in_fd);
 260
 261
 262   fd[1] = STDIN_FILENO;
 263 }
 264
 265
 266 /* Free resources, unlink temporary files and restore stdin and stdout. */
 267
 268 void
 269 reap_subpipe(pid_t pid, char const *program)
 270 {
 271   int argc;
 272
 273   for (argc = 0; arguments[argc]; argc++)
 274     free(arguments[argc]);
 275   free(arguments);
 276
 277   if (unlink(tmp_file_name[0]))
 278     error(EXIT_FAILURE, 0, _("removing of `%s' failed"), tmp_file_name[0]);
 279   if (unlink(tmp_file_name[1]))
 280     error(EXIT_FAILURE, 0, _("removing of `%s' failed"), tmp_file_name[1]);
 281
 282   if (dup2(old_stdin, STDIN_FILENO) < 0)
 283     error(EXIT_FAILURE, 0, "restore of bison's stdin failed");
 284   close(old_stdin);
 285 }