djgpp/subpipe.c

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