diff options
Diffstat (limited to 'lib/spawn-pipe.c')
| -rw-r--r-- | lib/spawn-pipe.c | 452 |
1 files changed, 452 insertions, 0 deletions
diff --git a/lib/spawn-pipe.c b/lib/spawn-pipe.c new file mode 100644 index 0000000..35567d4 --- /dev/null +++ b/lib/spawn-pipe.c @@ -0,0 +1,452 @@ +/* Creation of subprocesses, communicating via pipes. + Copyright (C) 2001-2004, 2006-2013 Free Software Foundation, Inc. + Written by Bruno Haible <haible@clisp.cons.org>, 2001. + + This program is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 3 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see <http://www.gnu.org/licenses/>. */ + + +#include <config.h> + +/* Specification. */ +#include "spawn-pipe.h" + +#include <errno.h> +#include <fcntl.h> +#include <stdlib.h> +#include <signal.h> +#include <unistd.h> + +#include "error.h" +#include "fatal-signal.h" +#include "unistd-safer.h" +#include "wait-process.h" +#include "gettext.h" + +#define _(str) gettext (str) + +#if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__ + +/* Native Windows API. */ +# include <process.h> +# include "w32spawn.h" + +#else + +/* Unix API. */ +# include <spawn.h> + +#endif + +/* The results of open() in this file are not used with fchdir, + therefore save some unnecessary work in fchdir.c. */ +#undef open +#undef close + + +#ifdef EINTR + +/* EINTR handling for close(). + These functions can return -1/EINTR even though we don't have any + signal handlers set up, namely when we get interrupted via SIGSTOP. */ + +static int +nonintr_close (int fd) +{ + int retval; + + do + retval = close (fd); + while (retval < 0 && errno == EINTR); + + return retval; +} +#define close nonintr_close + +#if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__ +static int +nonintr_open (const char *pathname, int oflag, mode_t mode) +{ + int retval; + + do + retval = open (pathname, oflag, mode); + while (retval < 0 && errno == EINTR); + + return retval; +} +# undef open /* avoid warning on VMS */ +# define open nonintr_open +#endif + +#endif + + +/* Open a pipe connected to a child process. + * + * write system read + * parent -> fd[1] -> STDIN_FILENO -> child if pipe_stdin + * parent <- fd[0] <- STDOUT_FILENO <- child if pipe_stdout + * read system write + * + * At least one of pipe_stdin, pipe_stdout must be true. + * pipe_stdin and prog_stdin together determine the child's standard input. + * pipe_stdout and prog_stdout together determine the child's standard output. + * If pipe_stdin is true, prog_stdin is ignored. + * If pipe_stdout is true, prog_stdout is ignored. + */ +static pid_t +create_pipe (const char *progname, + const char *prog_path, char **prog_argv, + bool pipe_stdin, bool pipe_stdout, + const char *prog_stdin, const char *prog_stdout, + bool null_stderr, + bool slave_process, bool exit_on_error, + int fd[2]) +{ +#if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__ + + /* Native Windows API. + This uses _pipe(), dup2(), and spawnv(). It could also be implemented + using the low-level functions CreatePipe(), DuplicateHandle(), + CreateProcess() and _open_osfhandle(); see the GNU make and GNU clisp + and cvs source code. */ + int ifd[2]; + int ofd[2]; + int orig_stdin; + int orig_stdout; + int orig_stderr; + int child; + int nulloutfd; + int stdinfd; + int stdoutfd; + int saved_errno; + + /* FIXME: Need to free memory allocated by prepare_spawn. */ + prog_argv = prepare_spawn (prog_argv); + + if (pipe_stdout) + if (pipe2_safer (ifd, O_BINARY | O_CLOEXEC) < 0) + error (EXIT_FAILURE, errno, _("cannot create pipe")); + if (pipe_stdin) + if (pipe2_safer (ofd, O_BINARY | O_CLOEXEC) < 0) + error (EXIT_FAILURE, errno, _("cannot create pipe")); +/* Data flow diagram: + * + * write system read + * parent -> ofd[1] -> ofd[0] -> child if pipe_stdin + * parent <- ifd[0] <- ifd[1] <- child if pipe_stdout + * read system write + * + */ + + /* Save standard file handles of parent process. */ + if (pipe_stdin || prog_stdin != NULL) + orig_stdin = dup_safer_noinherit (STDIN_FILENO); + if (pipe_stdout || prog_stdout != NULL) + orig_stdout = dup_safer_noinherit (STDOUT_FILENO); + if (null_stderr) + orig_stderr = dup_safer_noinherit (STDERR_FILENO); + child = -1; + + /* Create standard file handles of child process. */ + nulloutfd = -1; + stdinfd = -1; + stdoutfd = -1; + if ((!pipe_stdin || dup2 (ofd[0], STDIN_FILENO) >= 0) + && (!pipe_stdout || dup2 (ifd[1], STDOUT_FILENO) >= 0) + && (!null_stderr + || ((nulloutfd = open ("NUL", O_RDWR, 0)) >= 0 + && (nulloutfd == STDERR_FILENO + || (dup2 (nulloutfd, STDERR_FILENO) >= 0 + && close (nulloutfd) >= 0)))) + && (pipe_stdin + || prog_stdin == NULL + || ((stdinfd = open (prog_stdin, O_RDONLY, 0)) >= 0 + && (stdinfd == STDIN_FILENO + || (dup2 (stdinfd, STDIN_FILENO) >= 0 + && close (stdinfd) >= 0)))) + && (pipe_stdout + || prog_stdout == NULL + || ((stdoutfd = open (prog_stdout, O_WRONLY, 0)) >= 0 + && (stdoutfd == STDOUT_FILENO + || (dup2 (stdoutfd, STDOUT_FILENO) >= 0 + && close (stdoutfd) >= 0))))) + /* The child process doesn't inherit ifd[0], ifd[1], ofd[0], ofd[1], + but it inherits all open()ed or dup2()ed file handles (which is what + we want in the case of STD*_FILENO). */ + /* Use spawnvpe and pass the environment explicitly. This is needed if + the program has modified the environment using putenv() or [un]setenv(). + On Windows, programs have two environments, one in the "environment + block" of the process and managed through SetEnvironmentVariable(), and + one inside the process, in the location retrieved by the 'environ' + macro. When using spawnvp() without 'e', the child process inherits a + copy of the environment block - ignoring the effects of putenv() and + [un]setenv(). */ + { + child = spawnvpe (P_NOWAIT, prog_path, (const char **) prog_argv, + (const char **) environ); + if (child < 0 && errno == ENOEXEC) + { + /* prog is not a native executable. Try to execute it as a + shell script. Note that prepare_spawn() has already prepended + a hidden element "sh.exe" to prog_argv. */ + --prog_argv; + child = spawnvpe (P_NOWAIT, prog_argv[0], (const char **) prog_argv, + (const char **) environ); + } + } + if (child == -1) + saved_errno = errno; + if (stdinfd >= 0) + close (stdinfd); + if (stdoutfd >= 0) + close (stdoutfd); + if (nulloutfd >= 0) + close (nulloutfd); + + /* Restore standard file handles of parent process. */ + if (null_stderr) + undup_safer_noinherit (orig_stderr, STDERR_FILENO); + if (pipe_stdout || prog_stdout != NULL) + undup_safer_noinherit (orig_stdout, STDOUT_FILENO); + if (pipe_stdin || prog_stdin != NULL) + undup_safer_noinherit (orig_stdin, STDIN_FILENO); + + if (pipe_stdin) + close (ofd[0]); + if (pipe_stdout) + close (ifd[1]); + if (child == -1) + { + if (exit_on_error || !null_stderr) + error (exit_on_error ? EXIT_FAILURE : 0, saved_errno, + _("%s subprocess failed"), progname); + if (pipe_stdout) + close (ifd[0]); + if (pipe_stdin) + close (ofd[1]); + errno = saved_errno; + return -1; + } + + if (pipe_stdout) + fd[0] = ifd[0]; + if (pipe_stdin) + fd[1] = ofd[1]; + return child; + +#else + + /* Unix API. */ + int ifd[2]; + int ofd[2]; + sigset_t blocked_signals; + posix_spawn_file_actions_t actions; + bool actions_allocated; + posix_spawnattr_t attrs; + bool attrs_allocated; + int err; + pid_t child; + + if (pipe_stdout) + if (pipe_safer (ifd) < 0) + error (EXIT_FAILURE, errno, _("cannot create pipe")); + if (pipe_stdin) + if (pipe_safer (ofd) < 0) + error (EXIT_FAILURE, errno, _("cannot create pipe")); +/* Data flow diagram: + * + * write system read + * parent -> ofd[1] -> ofd[0] -> child if pipe_stdin + * parent <- ifd[0] <- ifd[1] <- child if pipe_stdout + * read system write + * + */ + + if (slave_process) + { + sigprocmask (SIG_SETMASK, NULL, &blocked_signals); + block_fatal_signals (); + } + actions_allocated = false; + attrs_allocated = false; + if ((err = posix_spawn_file_actions_init (&actions)) != 0 + || (actions_allocated = true, + (pipe_stdin + && (err = posix_spawn_file_actions_adddup2 (&actions, + ofd[0], STDIN_FILENO)) + != 0) + || (pipe_stdout + && (err = posix_spawn_file_actions_adddup2 (&actions, + ifd[1], STDOUT_FILENO)) + != 0) + || (pipe_stdin + && (err = posix_spawn_file_actions_addclose (&actions, ofd[0])) + != 0) + || (pipe_stdout + && (err = posix_spawn_file_actions_addclose (&actions, ifd[1])) + != 0) + || (pipe_stdin + && (err = posix_spawn_file_actions_addclose (&actions, ofd[1])) + != 0) + || (pipe_stdout + && (err = posix_spawn_file_actions_addclose (&actions, ifd[0])) + != 0) + || (null_stderr + && (err = posix_spawn_file_actions_addopen (&actions, + STDERR_FILENO, + "/dev/null", O_RDWR, + 0)) + != 0) + || (!pipe_stdin + && prog_stdin != NULL + && (err = posix_spawn_file_actions_addopen (&actions, + STDIN_FILENO, + prog_stdin, O_RDONLY, + 0)) + != 0) + || (!pipe_stdout + && prog_stdout != NULL + && (err = posix_spawn_file_actions_addopen (&actions, + STDOUT_FILENO, + prog_stdout, O_WRONLY, + 0)) + != 0) + || (slave_process + && ((err = posix_spawnattr_init (&attrs)) != 0 + || (attrs_allocated = true, + (err = posix_spawnattr_setsigmask (&attrs, + &blocked_signals)) + != 0 + || (err = posix_spawnattr_setflags (&attrs, + POSIX_SPAWN_SETSIGMASK)) + != 0))) + || (err = posix_spawnp (&child, prog_path, &actions, + attrs_allocated ? &attrs : NULL, prog_argv, + environ)) + != 0)) + { + if (actions_allocated) + posix_spawn_file_actions_destroy (&actions); + if (attrs_allocated) + posix_spawnattr_destroy (&attrs); + if (slave_process) + unblock_fatal_signals (); + if (exit_on_error || !null_stderr) + error (exit_on_error ? EXIT_FAILURE : 0, err, + _("%s subprocess failed"), progname); + if (pipe_stdout) + { + close (ifd[0]); + close (ifd[1]); + } + if (pipe_stdin) + { + close (ofd[0]); + close (ofd[1]); + } + errno = err; + return -1; + } + posix_spawn_file_actions_destroy (&actions); + if (attrs_allocated) + posix_spawnattr_destroy (&attrs); + if (slave_process) + { + register_slave_subprocess (child); + unblock_fatal_signals (); + } + if (pipe_stdin) + close (ofd[0]); + if (pipe_stdout) + close (ifd[1]); + + if (pipe_stdout) + fd[0] = ifd[0]; + if (pipe_stdin) + fd[1] = ofd[1]; + return child; + +#endif +} + +/* Open a bidirectional pipe. + * + * write system read + * parent -> fd[1] -> STDIN_FILENO -> child + * parent <- fd[0] <- STDOUT_FILENO <- child + * read system write + * + */ +pid_t +create_pipe_bidi (const char *progname, + const char *prog_path, char **prog_argv, + bool null_stderr, + bool slave_process, bool exit_on_error, + int fd[2]) +{ + pid_t result = create_pipe (progname, prog_path, prog_argv, + true, true, NULL, NULL, + null_stderr, slave_process, exit_on_error, + fd); + return result; +} + +/* Open a pipe for input from a child process. + * The child's stdin comes from a file. + * + * read system write + * parent <- fd[0] <- STDOUT_FILENO <- child + * + */ +pid_t +create_pipe_in (const char *progname, + const char *prog_path, char **prog_argv, + const char *prog_stdin, bool null_stderr, + bool slave_process, bool exit_on_error, + int fd[1]) +{ + int iofd[2]; + pid_t result = create_pipe (progname, prog_path, prog_argv, + false, true, prog_stdin, NULL, + null_stderr, slave_process, exit_on_error, + iofd); + if (result != -1) + fd[0] = iofd[0]; + return result; +} + +/* Open a pipe for output to a child process. + * The child's stdout goes to a file. + * + * write system read + * parent -> fd[0] -> STDIN_FILENO -> child + * + */ +pid_t +create_pipe_out (const char *progname, + const char *prog_path, char **prog_argv, + const char *prog_stdout, bool null_stderr, + bool slave_process, bool exit_on_error, + int fd[1]) +{ + int iofd[2]; + pid_t result = create_pipe (progname, prog_path, prog_argv, + true, false, NULL, prog_stdout, + null_stderr, slave_process, exit_on_error, + iofd); + if (result != -1) + fd[0] = iofd[1]; + return result; +} |