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