djgpp/subpipe.c

   1 /* Subprocesses with pipes.
   2
   3    Copyright (C) 2005, 2006, 2007, 2008-2009 Free Software Foundation,
   4    Inc.
   5
   6    This program 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 of the License, or
   9    (at your option) any later version.
  10
  11    This program 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    You should have received a copy of the GNU General Public License
  17    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  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   char *tmpdir;
  72   int fd;
  73
  74   tmpdir = getenv("TMPDIR");
  75   if (tmpdir == NULL)
  76     tmpdir = getenv("TMP");
  77   if (tmpdir == NULL)
  78     tmpdir = getenv("TEMP");
  79   if (access(tmpdir, D_OK))
  80     tmpdir = ".";
  81
  82   strcpy(tmp_file_name[0], tmpdir);
  83   strcat(tmp_file_name[0], "/bnXXXXXX");
  84   fd = mkstemp(tmp_file_name[0]);
  85   if (fd < 0)
  86     error(EXIT_FAILURE, 0, _("creation of a temporary file failed"));
  87   close (fd);
  88
  89   strcpy(tmp_file_name[1], tmpdir);
  90   strcat(tmp_file_name[1], "/bnXXXXXX");
  91   fd = mkstemp(tmp_file_name[1]);
  92   if (fd < 0)
  93     error(EXIT_FAILURE, 0, _("creation of a temporary file failed"));
  94   close (fd);
  95 }
  96
  97
  98 /* Create a subprocess that is run as a filter.  ARGV is the
  99    NULL-terminated argument vector for the subprocess.  Store read and
 100    write file descriptors for communication with the subprocess into
 101    FD[0] and FD[1]: input meant for the process can be written into
 102    FD[0], and output from the process can be read from FD[1].  Return
 103    the subprocess id.
 104
 105    Because DOS has neither fork nor pipe functionality to run the subprocess
 106    as a filter, the filter is reproduced using temporary files. First bison's
 107    stdout is redirected to a temporary file. After bison has produced all of
 108    is output, this file is closed and connected to m4's stdin. All m4's output
 109    is redirected from m4's stdout to a second temporary file and reopened as
 110    bison's stdin. */
 111
 112 pid_t
 113 create_subpipe(char const *const *argv, int fd[2])
 114 {
 115   int argc;
 116   int from_in_fd;  /* pipe from bison to m4. */
 117   pid_t pid;
 118
 119
 120   pid = getpid();
 121
 122   /*
 123    *  Save original stdin and stdout
 124    *  for later restauration.
 125    */
 126   old_stdin = dup(STDIN_FILENO);
 127   if (old_stdin < 0)
 128     error(EXIT_FAILURE, 0, _("saving stdin failed"));
 129
 130   old_stdout = dup(STDOUT_FILENO);
 131   if (old_stdout < 0)
 132     error(EXIT_FAILURE, 0, _("saving stdout failed"));
 133
 134   /*
 135    *  Save argv for later use.
 136    */
 137   for (argc = 0; argv[argc]; argc++)
 138     ;
 139   argc++;
 140   arguments = xmalloc(argc * sizeof(arguments[0]));
 141   for (argc = 0; argv[argc]; argc++)
 142   {
 143     arguments[argc] = xmalloc((strlen(argv[argc]) + 1) * sizeof(arguments[0][0]));
 144     strcpy(arguments[argc], argv[argc]);
 145   }
 146   arguments[argc] = NULL;
 147
 148   /*
 149    *  All bison's output will be gathered in this temporary file
 150    *  and will be redirected to m4's stdin.
 151    */
 152   from_in_fd = open(tmp_file_name[0], O_WRONLY | O_CREAT | O_TRUNC, S_IWUSR);
 153   if (from_in_fd < 0)
 154     error(EXIT_FAILURE, 0, _("opening of tmpfile failed"));
 155   if (dup2(from_in_fd, STDOUT_FILENO) < 0)
 156   {
 157     remove_tmp_file(from_in_fd, tmp_file_name[0]);
 158     error(EXIT_FAILURE, 0, _("redirecting bison's stdout to the temporary file failed"));
 159   }
 160   close(from_in_fd);
 161
 162
 163   fd[0] = STDOUT_FILENO;
 164   return pid;
 165 }
 166
 167
 168 /* A signal handler that just records that a signal has happened. */
 169 static int child_interrupted;
 170
 171 static void
 172 signal_catcher(int signo)
 173 {
 174   child_interrupted++;
 175 }
 176
 177
 178 void
 179 end_of_output_subpipe(pid_t pid, int fd[2])
 180 {
 181   char *program;
 182   int from_out_fd = open(tmp_file_name[0], O_RDONLY, S_IRUSR);                   /* pipe from bison to m4. */
 183   int to_in_fd = open(tmp_file_name[1], O_WRONLY | O_CREAT | O_TRUNC, S_IWUSR);  /* pipe from m4 to bison. */
 184   int status;
 185   void (*previous_handler)(int);
 186
 187
 188   program = strrchr(arguments[0], '/');
 189   if (program)
 190     program++;
 191   else
 192     program = arguments[0];
 193
 194   /*
 195    *  Redirect bison's output to m4's stdin.
 196    */
 197   if (from_out_fd < 0)
 198     error(EXIT_FAILURE, 0, _("opening of tmpfile failed"));
 199   if (dup2(from_out_fd, STDIN_FILENO) < 0)
 200   {
 201     remove_tmp_file(from_out_fd, tmp_file_name[0]);
 202     error(EXIT_FAILURE, 0, _("redirecting m4's stdin from the temporary file failed"));
 203   }
 204   close(from_out_fd);
 205
 206   /*
 207    *  All m4's output will be gathered in this temporary file
 208    *  and will be redirected to bison's stdin.
 209    */
 210   if (to_in_fd < 0)
 211   {
 212     remove_tmp_file(STDIN_FILENO, tmp_file_name[0]);
 213     error(EXIT_FAILURE, 0, _("opening of a temporary file failed"));
 214   }
 215   if (dup2(to_in_fd, STDOUT_FILENO) < 0)
 216   {
 217     remove_tmp_file(STDIN_FILENO, tmp_file_name[0]);
 218     remove_tmp_file(to_in_fd, tmp_file_name[1]);
 219     error(EXIT_FAILURE, 0, _("redirecting m4's stdout to a temporary file failed"));
 220   }
 221   close(to_in_fd);
 222
 223   /*
 224    *  Run m4.
 225    */
 226   child_interrupted = 0;
 227   errno = 0;
 228   previous_handler = signal(SIGINT, signal_catcher);
 229   status = spawnvp(P_WAIT, program, arguments);
 230   signal(SIGINT, previous_handler);
 231   if (child_interrupted)
 232   {
 233     remove_tmp_file(STDIN_FILENO, tmp_file_name[0]);
 234     remove_tmp_file(STDOUT_FILENO, tmp_file_name[1]);
 235     error(EXIT_FAILURE, 0, _("subsidiary program `%s' interrupted"), program);
 236   }
 237   if (status)
 238   {
 239     remove_tmp_file(STDIN_FILENO, tmp_file_name[0]);
 240     remove_tmp_file(STDOUT_FILENO, tmp_file_name[1]);
 241     error(EXIT_FAILURE, 0, _(errno == ENOENT
 242                              ? "subsidiary program `%s' not found"
 243                              : status < 1
 244                              ? "subsidiary program `%s' failed"
 245                              : "subsidiary program `%s' failed (status=%i, errno=%i)"), program, status, errno);
 246   }
 247
 248
 249   /*
 250    *  Redirect m4's output to bison's stdin.
 251    */
 252   if (dup2(old_stdout, STDOUT_FILENO) < 0)
 253     error(EXIT_FAILURE, 0, "restore of bison's stdout failed");
 254   close(old_stdout);
 255   to_in_fd = open(tmp_file_name[1], O_RDONLY, S_IRUSR);  /* pipe from m4 to bison. */
 256   if (to_in_fd < 0)
 257   {
 258     remove_tmp_file(STDIN_FILENO, tmp_file_name[0]);
 259     error(EXIT_FAILURE, 0, _("opening of tmpfile failed"));
 260   }
 261   if (dup2(to_in_fd, STDIN_FILENO) < 0)
 262   {
 263     remove_tmp_file(STDIN_FILENO, tmp_file_name[0]);
 264     remove_tmp_file(to_in_fd, tmp_file_name[1]);
 265     error(EXIT_FAILURE, -1, "dup2");
 266     error(EXIT_FAILURE, 0, _("redirecting bison's stdin from the temporary file failed"));
 267   }
 268   close(to_in_fd);
 269
 270
 271   fd[1] = STDIN_FILENO;
 272 }
 273
 274
 275 /* Free resources, unlink temporary files and restore stdin and stdout. */
 276
 277 void
 278 reap_subpipe(pid_t pid, char const *program)
 279 {
 280   int argc;
 281
 282   for (argc = 0; arguments[argc]; argc++)
 283     free(arguments[argc]);
 284   free(arguments);
 285
 286   if (unlink(tmp_file_name[0]))
 287     error(EXIT_FAILURE, 0, _("removing of `%s' failed"), tmp_file_name[0]);
 288   if (unlink(tmp_file_name[1]))
 289     error(EXIT_FAILURE, 0, _("removing of `%s' failed"), tmp_file_name[1]);
 290
 291   if (dup2(old_stdin, STDIN_FILENO) < 0)
 292     error(EXIT_FAILURE, 0, "restore of bison's stdin failed");
 293   close(old_stdin);
 294 }