1 /* Creation of subprocesses, communicating via pipes.
2 Copyright (C) 2001-2004, 2006-2013 Free Software Foundation, Inc.
3 Written by Bruno Haible <haible@clisp.cons.org>, 2001.
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.
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.
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/>. */
22 #include "spawn-pipe.h"
31 #include "fatal-signal.h"
32 #include "unistd-safer.h"
33 #include "wait-process.h"
36 #define _(str) gettext (str)
38 #if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
40 /* Native Windows API. */
42 # include "w32spawn.h"
51 /* The results of open() in this file are not used with fchdir,
52 therefore save some unnecessary work in fchdir.c. */
59 /* EINTR handling for close().
60 These functions can return -1/EINTR even though we don't have any
61 signal handlers set up, namely when we get interrupted via SIGSTOP. */
64 nonintr_close (int fd)
70 while (retval < 0 && errno == EINTR);
74 #define close nonintr_close
76 #if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
78 nonintr_open (const char *pathname, int oflag, mode_t mode)
83 retval = open (pathname, oflag, mode);
84 while (retval < 0 && errno == EINTR);
88 # undef open /* avoid warning on VMS */
89 # define open nonintr_open
95 /* Open a pipe connected to a child process.
98 * parent -> fd[1] -> STDIN_FILENO -> child if pipe_stdin
99 * parent <- fd[0] <- STDOUT_FILENO <- child if pipe_stdout
102 * At least one of pipe_stdin, pipe_stdout must be true.
103 * pipe_stdin and prog_stdin together determine the child's standard input.
104 * pipe_stdout and prog_stdout together determine the child's standard output.
105 * If pipe_stdin is true, prog_stdin is ignored.
106 * If pipe_stdout is true, prog_stdout is ignored.
109 create_pipe (const char *progname,
110 const char *prog_path, char **prog_argv,
111 bool pipe_stdin, bool pipe_stdout,
112 const char *prog_stdin, const char *prog_stdout,
114 bool slave_process, bool exit_on_error,
117 #if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
119 /* Native Windows API.
120 This uses _pipe(), dup2(), and spawnv(). It could also be implemented
121 using the low-level functions CreatePipe(), DuplicateHandle(),
122 CreateProcess() and _open_osfhandle(); see the GNU make and GNU clisp
123 and cvs source code. */
135 /* FIXME: Need to free memory allocated by prepare_spawn. */
136 prog_argv = prepare_spawn (prog_argv);
139 if (pipe2_safer (ifd, O_BINARY | O_CLOEXEC) < 0)
140 error (EXIT_FAILURE, errno, _("cannot create pipe"));
142 if (pipe2_safer (ofd, O_BINARY | O_CLOEXEC) < 0)
143 error (EXIT_FAILURE, errno, _("cannot create pipe"));
144 /* Data flow diagram:
147 * parent -> ofd[1] -> ofd[0] -> child if pipe_stdin
148 * parent <- ifd[0] <- ifd[1] <- child if pipe_stdout
153 /* Save standard file handles of parent process. */
154 if (pipe_stdin || prog_stdin != NULL)
155 orig_stdin = dup_safer_noinherit (STDIN_FILENO);
156 if (pipe_stdout || prog_stdout != NULL)
157 orig_stdout = dup_safer_noinherit (STDOUT_FILENO);
159 orig_stderr = dup_safer_noinherit (STDERR_FILENO);
162 /* Create standard file handles of child process. */
166 if ((!pipe_stdin || dup2 (ofd[0], STDIN_FILENO) >= 0)
167 && (!pipe_stdout || dup2 (ifd[1], STDOUT_FILENO) >= 0)
169 || ((nulloutfd = open ("NUL", O_RDWR, 0)) >= 0
170 && (nulloutfd == STDERR_FILENO
171 || (dup2 (nulloutfd, STDERR_FILENO) >= 0
172 && close (nulloutfd) >= 0))))
174 || prog_stdin == NULL
175 || ((stdinfd = open (prog_stdin, O_RDONLY, 0)) >= 0
176 && (stdinfd == STDIN_FILENO
177 || (dup2 (stdinfd, STDIN_FILENO) >= 0
178 && close (stdinfd) >= 0))))
180 || prog_stdout == NULL
181 || ((stdoutfd = open (prog_stdout, O_WRONLY, 0)) >= 0
182 && (stdoutfd == STDOUT_FILENO
183 || (dup2 (stdoutfd, STDOUT_FILENO) >= 0
184 && close (stdoutfd) >= 0)))))
185 /* The child process doesn't inherit ifd[0], ifd[1], ofd[0], ofd[1],
186 but it inherits all open()ed or dup2()ed file handles (which is what
187 we want in the case of STD*_FILENO). */
188 /* Use spawnvpe and pass the environment explicitly. This is needed if
189 the program has modified the environment using putenv() or [un]setenv().
190 On Windows, programs have two environments, one in the "environment
191 block" of the process and managed through SetEnvironmentVariable(), and
192 one inside the process, in the location retrieved by the 'environ'
193 macro. When using spawnvp() without 'e', the child process inherits a
194 copy of the environment block - ignoring the effects of putenv() and
197 child = spawnvpe (P_NOWAIT, prog_path, (const char **) prog_argv,
198 (const char **) environ);
199 if (child < 0 && errno == ENOEXEC)
201 /* prog is not a native executable. Try to execute it as a
202 shell script. Note that prepare_spawn() has already prepended
203 a hidden element "sh.exe" to prog_argv. */
205 child = spawnvpe (P_NOWAIT, prog_argv[0], (const char **) prog_argv,
206 (const char **) environ);
218 /* Restore standard file handles of parent process. */
220 undup_safer_noinherit (orig_stderr, STDERR_FILENO);
221 if (pipe_stdout || prog_stdout != NULL)
222 undup_safer_noinherit (orig_stdout, STDOUT_FILENO);
223 if (pipe_stdin || prog_stdin != NULL)
224 undup_safer_noinherit (orig_stdin, STDIN_FILENO);
232 if (exit_on_error || !null_stderr)
233 error (exit_on_error ? EXIT_FAILURE : 0, saved_errno,
234 _("%s subprocess failed"), progname);
254 sigset_t blocked_signals;
255 posix_spawn_file_actions_t actions;
256 bool actions_allocated;
257 posix_spawnattr_t attrs;
258 bool attrs_allocated;
263 if (pipe_safer (ifd) < 0)
264 error (EXIT_FAILURE, errno, _("cannot create pipe"));
266 if (pipe_safer (ofd) < 0)
267 error (EXIT_FAILURE, errno, _("cannot create pipe"));
268 /* Data flow diagram:
271 * parent -> ofd[1] -> ofd[0] -> child if pipe_stdin
272 * parent <- ifd[0] <- ifd[1] <- child if pipe_stdout
279 sigprocmask (SIG_SETMASK, NULL, &blocked_signals);
280 block_fatal_signals ();
282 actions_allocated = false;
283 attrs_allocated = false;
284 if ((err = posix_spawn_file_actions_init (&actions)) != 0
285 || (actions_allocated = true,
287 && (err = posix_spawn_file_actions_adddup2 (&actions,
288 ofd[0], STDIN_FILENO))
291 && (err = posix_spawn_file_actions_adddup2 (&actions,
292 ifd[1], STDOUT_FILENO))
295 && (err = posix_spawn_file_actions_addclose (&actions, ofd[0]))
298 && (err = posix_spawn_file_actions_addclose (&actions, ifd[1]))
301 && (err = posix_spawn_file_actions_addclose (&actions, ofd[1]))
304 && (err = posix_spawn_file_actions_addclose (&actions, ifd[0]))
307 && (err = posix_spawn_file_actions_addopen (&actions,
313 && prog_stdin != NULL
314 && (err = posix_spawn_file_actions_addopen (&actions,
316 prog_stdin, O_RDONLY,
320 && prog_stdout != NULL
321 && (err = posix_spawn_file_actions_addopen (&actions,
323 prog_stdout, O_WRONLY,
327 && ((err = posix_spawnattr_init (&attrs)) != 0
328 || (attrs_allocated = true,
329 (err = posix_spawnattr_setsigmask (&attrs,
332 || (err = posix_spawnattr_setflags (&attrs,
333 POSIX_SPAWN_SETSIGMASK))
335 || (err = posix_spawnp (&child, prog_path, &actions,
336 attrs_allocated ? &attrs : NULL, prog_argv,
340 if (actions_allocated)
341 posix_spawn_file_actions_destroy (&actions);
343 posix_spawnattr_destroy (&attrs);
345 unblock_fatal_signals ();
346 if (exit_on_error || !null_stderr)
347 error (exit_on_error ? EXIT_FAILURE : 0, err,
348 _("%s subprocess failed"), progname);
362 posix_spawn_file_actions_destroy (&actions);
364 posix_spawnattr_destroy (&attrs);
367 register_slave_subprocess (child);
368 unblock_fatal_signals ();
384 /* Open a bidirectional pipe.
387 * parent -> fd[1] -> STDIN_FILENO -> child
388 * parent <- fd[0] <- STDOUT_FILENO <- child
393 create_pipe_bidi (const char *progname,
394 const char *prog_path, char **prog_argv,
396 bool slave_process, bool exit_on_error,
399 pid_t result = create_pipe (progname, prog_path, prog_argv,
400 true, true, NULL, NULL,
401 null_stderr, slave_process, exit_on_error,
406 /* Open a pipe for input from a child process.
407 * The child's stdin comes from a file.
410 * parent <- fd[0] <- STDOUT_FILENO <- child
414 create_pipe_in (const char *progname,
415 const char *prog_path, char **prog_argv,
416 const char *prog_stdin, bool null_stderr,
417 bool slave_process, bool exit_on_error,
421 pid_t result = create_pipe (progname, prog_path, prog_argv,
422 false, true, prog_stdin, NULL,
423 null_stderr, slave_process, exit_on_error,
430 /* Open a pipe for output to a child process.
431 * The child's stdout goes to a file.
434 * parent -> fd[0] -> STDIN_FILENO -> child
438 create_pipe_out (const char *progname,
439 const char *prog_path, char **prog_argv,
440 const char *prog_stdout, bool null_stderr,
441 bool slave_process, bool exit_on_error,
445 pid_t result = create_pipe (progname, prog_path, prog_argv,
446 true, false, NULL, prog_stdout,
447 null_stderr, slave_process, exit_on_error,