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glib/gspawn.c
Sebastian Wilhelmi 9c574a6a9a Changed unportable __FUNCTION__ to the verbatim function name. 
2000-11-02  Sebastian Wilhelmi  <wilhelmi@ira.uka.de>

	* gspawn.c: Changed unportable __FUNCTION__ to the verbatim
	function name.
2000-11-02 12:31:10 +00:00

1398 lines
41 KiB
C
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/* gspawn.c - Process launching
*
* Copyright 2000 Red Hat, Inc.
* g_execvpe implementation based on GNU libc execvp:
* Copyright 1991, 92, 95, 96, 97, 98, 99 Free Software Foundation, Inc.
*
* GLib is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2 of the
* License, or (at your option) any later version.
*
* GLib 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with GLib; see the file COPYING.LIB. If not, write
* to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*/
#include "glib.h"
#include <sys/time.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>
#include <errno.h>
#include <fcntl.h>
#include <signal.h>
#include <string.h>
#ifdef HAVE_SYS_SELECT_H
#include <sys/select.h>
#endif /* HAVE_SYS_SELECT_H */
#ifdef _
#warning "FIXME remove gettext hack"
#endif
#define _(x) x
static gint g_execute (const gchar *file,
gchar **argv,
gchar **envp,
gboolean search_path);
static gboolean make_pipe (gint p[2],
GError **error);
static gboolean fork_exec_with_pipes (gboolean intermediate_child,
const gchar *working_directory,
gchar **argv,
gchar **envp,
gboolean close_descriptors,
gboolean search_path,
gboolean stdout_to_null,
gboolean stderr_to_null,
gboolean child_inherits_stdin,
GSpawnChildSetupFunc child_setup,
gpointer user_data,
gint *child_pid,
gint *standard_input,
gint *standard_output,
gint *standard_error,
GError **error);
GQuark
g_spawn_error_quark (void)
{
static GQuark quark = 0;
if (quark == 0)
quark = g_quark_from_static_string ("g-exec-error-quark");
return quark;
}
/**
* g_spawn_async:
* @working_directory: child's current working directory, or NULL to inherit parent's
* @argv: child's argument vector
* @envp: child's environment, or NULL to inherit parent's
* @flags: flags from #GSpawnFlags
* @child_setup: function to run in the child just before exec()
* @user_data: user data for @child_setup
* @child_pid: return location for child process ID, or NULL
* @error: return location for error
*
* See g_spawn_async_with_pipes() for a full description; this function
* simply calls the g_spawn_async_with_pipes() without any pipes.
*
* Return value: TRUE on success, FALSE if error is set
**/
gboolean
g_spawn_async (const gchar *working_directory,
gchar **argv,
gchar **envp,
GSpawnFlags flags,
GSpawnChildSetupFunc child_setup,
gpointer user_data,
gint *child_pid,
GError **error)
{
g_return_val_if_fail (argv != NULL, FALSE);
return g_spawn_async_with_pipes (working_directory,
argv, envp,
flags,
child_setup,
user_data,
child_pid,
NULL, NULL, NULL,
error);
}
/* Avoids a danger in threaded situations (calling close()
* on a file descriptor twice, and another thread has
* re-opened it since the first close)
*/
static gint
close_and_invalidate (gint *fd)
{
gint ret;
ret = close (*fd);
*fd = -1;
return ret;
}
typedef enum
{
READ_FAILED = 0, /* FALSE */
READ_OK,
READ_EOF
} ReadResult;
static ReadResult
read_data (GString *str,
gint fd,
GError **error)
{
gint bytes;
gchar buf[4096];
again:
bytes = read (fd, &buf, 4096);
if (bytes == 0)
return READ_EOF;
else if (bytes > 0)
{
g_string_append_len (str, buf, bytes);
return READ_OK;
}
else if (bytes < 0 && errno == EINTR)
goto again;
else if (bytes < 0)
{
g_set_error (error,
G_SPAWN_ERROR,
G_SPAWN_ERROR_READ,
_("Failed to read data from child process (%s)"),
g_strerror (errno));
return READ_FAILED;
}
else
return READ_OK;
}
/**
* g_spawn_sync:
* @working_directory: child's current working directory, or NULL to inherit parent's
* @argv: child's argument vector
* @envp: child's environment, or NULL to inherit parent's
* @flags: flags from #GSpawnFlags
* @child_setup: function to run in the child just before exec()
* @user_data: user data for @child_setup
* @standard_output: return location for child output
* @standard_error: return location for child error messages
* @exit_status: child exit status, as returned by waitpid()
* @error: return location for error
*
* Executes a child synchronously (waits for the child to exit before returning).
* All output from the child is stored in @standard_output and @standard_error,
* if those parameters are non-NULL. If @exit_status is non-NULL, the exit status
* of the child is stored there as it would be by waitpid(); standard UNIX
* macros such as WIFEXITED() and WEXITSTATUS() must be used to evaluate the
* exit status. If an error occurs, no data is returned in @standard_output,
* @standard_error, or @exit_status.
*
* This function calls g_spawn_async_with_pipes() internally; see that function
* for full details on the other parameters.
*
* Return value: TRUE on success, FALSE if an error was set.
**/
gboolean
g_spawn_sync (const gchar *working_directory,
gchar **argv,
gchar **envp,
GSpawnFlags flags,
GSpawnChildSetupFunc child_setup,
gpointer user_data,
gchar **standard_output,
gchar **standard_error,
gint *exit_status,
GError **error)
{
gint outpipe = -1;
gint errpipe = -1;
gint pid;
fd_set fds;
gint ret;
GString *outstr = NULL;
GString *errstr = NULL;
gboolean failed;
gint status;
g_return_val_if_fail (argv != NULL, FALSE);
g_return_val_if_fail (!(flags & G_SPAWN_DO_NOT_REAP_CHILD), FALSE);
g_return_val_if_fail (standard_output == NULL ||
!(flags & G_SPAWN_STDOUT_TO_DEV_NULL), FALSE);
g_return_val_if_fail (standard_error == NULL ||
!(flags & G_SPAWN_STDERR_TO_DEV_NULL), FALSE);
/* Just to ensure segfaults if callers try to use
* these when an error is reported.
*/
if (standard_output)
*standard_output = NULL;
if (standard_error)
*standard_error = NULL;
if (!fork_exec_with_pipes (FALSE,
working_directory,
argv,
envp,
!(flags & G_SPAWN_LEAVE_DESCRIPTORS_OPEN),
(flags & G_SPAWN_SEARCH_PATH) != 0,
(flags & G_SPAWN_STDOUT_TO_DEV_NULL) != 0,
(flags & G_SPAWN_STDERR_TO_DEV_NULL) != 0,
(flags & G_SPAWN_CHILD_INHERITS_STDIN) != 0,
child_setup,
user_data,
&pid,
NULL,
standard_output ? &outpipe : NULL,
standard_error ? &errpipe : NULL,
error))
return FALSE;
/* Read data from child. */
failed = FALSE;
if (outpipe >= 0)
{
outstr = g_string_new ("");
}
if (errpipe >= 0)
{
errstr = g_string_new ("");
}
/* Read data until we get EOF on both pipes. */
while (!failed &&
(outpipe >= 0 ||
errpipe >= 0))
{
ret = 0;
FD_ZERO (&fds);
if (outpipe >= 0)
FD_SET (outpipe, &fds);
if (errpipe >= 0)
FD_SET (errpipe, &fds);
ret = select (MAX (outpipe, errpipe) + 1,
&fds,
NULL, NULL,
NULL /* no timeout */);
if (ret < 0 && errno != EINTR)
{
failed = TRUE;
g_set_error (error,
G_SPAWN_ERROR,
G_SPAWN_ERROR_READ,
_("Unexpected error in select() reading data from a child process (%s)"),
g_strerror (errno));
break;
}
if (outpipe >= 0 && FD_ISSET (outpipe, &fds))
{
switch (read_data (outstr, outpipe, error))
{
case READ_FAILED:
failed = TRUE;
break;
case READ_EOF:
close_and_invalidate (&outpipe);
outpipe = -1;
break;
default:
break;
}
if (failed)
break;
}
if (errpipe >= 0 && FD_ISSET (errpipe, &fds))
{
switch (read_data (errstr, errpipe, error))
{
case READ_FAILED:
failed = TRUE;
break;
case READ_EOF:
close_and_invalidate (&errpipe);
errpipe = -1;
break;
default:
break;
}
if (failed)
break;
}
}
/* These should only be open still if we had an error. */
if (outpipe >= 0)
close_and_invalidate (&outpipe);
if (errpipe >= 0)
close_and_invalidate (&errpipe);
/* Wait for child to exit, even if we have
* an error pending.
*/
again:
ret = waitpid (pid, &status, 0);
if (ret < 0)
{
if (errno == EINTR)
goto again;
else if (errno == ECHILD)
{
if (exit_status)
{
g_warning ("In call to g_spawn_sync(), exit status of a child process was requested but SIGCHLD action was set to SIG_IGN and ECHILD was received by waitpid(), so exit status can't be returned. This is a bug in the program calling g_spawn_sync(); either don't request the exit status, or don't set the SIGCHLD action.");
}
else
{
/* We don't need the exit status. */
}
}
else
{
if (!failed) /* avoid error pileups */
{
failed = TRUE;
g_set_error (error,
G_SPAWN_ERROR,
G_SPAWN_ERROR_READ,
_("Unexpected error in waitpid() (%s)"),
g_strerror (errno));
}
}
}
if (failed)
{
if (outstr)
g_string_free (outstr, TRUE);
if (errstr)
g_string_free (errstr, TRUE);
return FALSE;
}
else
{
if (exit_status)
*exit_status = status;
if (standard_output)
*standard_output = g_string_free (outstr, FALSE);
if (standard_error)
*standard_error = g_string_free (errstr, FALSE);
return TRUE;
}
}
/**
* g_spawn_async_with_pipes:
* @working_directory: child's current working directory, or NULL to inherit parent's
* @argv: child's argument vector
* @envp: child's environment, or NULL to inherit parent's
* @flags: flags from #GSpawnFlags
* @child_setup: function to run in the child just before exec()
* @user_data: user data for @child_setup
* @child_pid: return location for child process ID, or NULL
* @standard_input: return location for file descriptor to write to child's stdin, or NULL
* @standard_output: return location for file descriptor to read child's stdout, or NULL
* @standard_error: return location for file descriptor to read child's stderr, or NULL
* @error: return location for error
*
* Executes a child program asynchronously (your program will not
* block waiting for the child to exit). The child program is
* specified by the only argument that must be provided, @argv. @argv
* should be a NULL-terminated array of strings, to be passed as the
* argument vector for the child. The first string in @argv is of
* course the name of the program to execute. By default, the name of
* the program must be a full path; the PATH shell variable will only
* be searched if you pass the %G_SPAWN_SEARCH_PATH flag.
*
* @envp is a NULL-terminated array of strings, where each string
* has the form <literal>KEY=VALUE</literal>. This will become
* the child's environment. If @envp is NULL, the child inherits its
* parent's environment.
*
* @flags should be the bitwise OR of any flags you want to affect the
* function's behavior. The %G_SPAWN_DO_NOT_REAP_CHILD means that the
* child will not be automatically reaped; you must call waitpid() or
* handle SIGCHLD yourself, or the child will become a zombie.
* %G_SPAWN_LEAVE_DESCRIPTORS_OPEN means that the parent's open file
* descriptors will be inherited by the child; otherwise all
* descriptors except stdin/stdout/stderr will be closed before
* calling exec() in the child. %G_SPAWN_SEARCH_PATH means that
* <literal>argv[0]</literal> need not be an absolute path, it
* will be looked for in the user's PATH. %G_SPAWN_STDOUT_TO_DEV_NULL
* means that the child's standad output will be discarded, instead
* of going to the same location as the parent's standard output.
* %G_SPAWN_STDERR_TO_DEV_NULL means that the child's standard error
* will be discarded. %G_SPAWN_CHILD_INHERITS_STDIN means that
* the child will inherit the parent's standard input (by default,
* the child's standard input is attached to /dev/null).
*
* @child_setup and @user_data are a function and user data to be
* called in the child after GLib has performed all the setup it plans
* to perform (including creating pipes, closing file descriptors,
* etc.) but before calling exec(). That is, @child_setup is called
* just before calling exec() in the child. Obviously actions taken in
* this function will only affect the child, not the parent.
*
* If non-NULL, @child_pid will be filled with the child's process
* ID. You can use the process ID to send signals to the child, or
* to waitpid() if you specified the %G_SPAWN_DO_NOT_REAP_CHILD flag.
*
* If non-NULL, the @standard_input, @standard_output, @standard_error
* locations will be filled with file descriptors for writing to the child's
* standard input or reading from its standard output or standard error.
* The caller of g_spawn_async_with_pipes() must close these file descriptors
* when they are no longer in use. If these parameters are NULL, the
* corresponding pipe won't be created.
*
* @error can be NULL to ignore errors, or non-NULL to report errors.
* If an error is set, the function returns FALSE. Errors
* are reported even if they occur in the child (for example if the
* executable in <literal>argv[0]</literal> is not found). Typically
* the <literal>message</literal> field of returned errors should be displayed
* to users. Possible errors are those from the #G_SPAWN_ERROR domain.
*
* If an error occurs, @child_pid, @standard_input, @standard_output,
* and @standard_error will not be filled with valid values.
*
* Return value: TRUE on success, FALSE if an error was set
**/
gboolean
g_spawn_async_with_pipes (const gchar *working_directory,
gchar **argv,
gchar **envp,
GSpawnFlags flags,
GSpawnChildSetupFunc child_setup,
gpointer user_data,
gint *child_pid,
gint *standard_input,
gint *standard_output,
gint *standard_error,
GError **error)
{
g_return_val_if_fail (argv != NULL, FALSE);
g_return_val_if_fail (standard_output == NULL ||
!(flags & G_SPAWN_STDOUT_TO_DEV_NULL), FALSE);
g_return_val_if_fail (standard_error == NULL ||
!(flags & G_SPAWN_STDERR_TO_DEV_NULL), FALSE);
/* can't inherit stdin if we have an input pipe. */
g_return_val_if_fail (standard_input == NULL ||
!(flags & G_SPAWN_CHILD_INHERITS_STDIN), FALSE);
return fork_exec_with_pipes (!(flags & G_SPAWN_DO_NOT_REAP_CHILD),
working_directory,
argv,
envp,
!(flags & G_SPAWN_LEAVE_DESCRIPTORS_OPEN),
(flags & G_SPAWN_SEARCH_PATH) != 0,
(flags & G_SPAWN_STDOUT_TO_DEV_NULL) != 0,
(flags & G_SPAWN_STDERR_TO_DEV_NULL) != 0,
(flags & G_SPAWN_CHILD_INHERITS_STDIN) != 0,
child_setup,
user_data,
child_pid,
standard_input,
standard_output,
standard_error,
error);
}
/**
* g_spawn_command_line_sync:
* @command_line: a command line
* @standard_output: return location for child output
* @standard_error: return location for child errors
* @exit_status: return location for child exit status
* @error: return location for errors
*
* A simple version of g_spawn_sync() with little-used parameters
* removed, taking a command line instead of an argument vector. See
* g_spawn_sync() for full details. @command_line will be parsed by
* g_shell_parse_argv(). Unlike g_spawn_sync(), the %G_SPAWN_SEARCH_PATH flag
* is enabled. Note that %G_SPAWN_SEARCH_PATH can have security
* implications, so consider using g_spawn_sync() directly if
* appropriate. Possible errors are those from g_spawn_sync() and those
* from g_shell_parse_argv().
*
* Return value: TRUE on success, FALSE if an error was set
**/
gboolean
g_spawn_command_line_sync (const gchar *command_line,
gchar **standard_output,
gchar **standard_error,
gint *exit_status,
GError **error)
{
gboolean retval;
gchar **argv = 0;
g_return_val_if_fail (command_line != NULL, FALSE);
if (!g_shell_parse_argv (command_line,
NULL, &argv,
error))
return FALSE;
retval = g_spawn_sync (NULL,
argv,
NULL,
G_SPAWN_SEARCH_PATH,
NULL,
NULL,
standard_output,
standard_error,
exit_status,
error);
g_strfreev (argv);
return retval;
}
/**
* g_spawn_command_line_async:
* @command_line: a command line
* @error: return location for errors
*
* A simple version of g_spawn_async() that parses a command line with
* g_shell_parse_argv() and passes it to g_spawn_async(). Runs a
* command line in the background. Unlike g_spawn_async(), the
* %G_SPAWN_SEARCH_PATH flag is enabled, other flags are not. Note
* that %G_SPAWN_SEARCH_PATH can have security implications, so
* consider using g_spawn_async() directly if appropriate. Possible
* errors are those from g_shell_parse_argv() and g_spawn_async().
*
* Return value: TRUE on success, FALSE if error is set.
**/
gboolean
g_spawn_command_line_async (const gchar *command_line,
GError **error)
{
gboolean retval;
gchar **argv = 0;
g_return_val_if_fail (command_line != NULL, FALSE);
if (!g_shell_parse_argv (command_line,
NULL, &argv,
error))
return FALSE;
retval = g_spawn_async (NULL,
argv,
NULL,
G_SPAWN_SEARCH_PATH,
NULL,
NULL,
NULL,
error);
g_strfreev (argv);
return retval;
}
static gint
exec_err_to_g_error (gint en)
{
switch (en)
{
#ifdef EACCES
case EACCES:
return G_SPAWN_ERROR_ACCES;
break;
#endif
#ifdef EPERM
case EPERM:
return G_SPAWN_ERROR_PERM;
break;
#endif
#ifdef E2BIG
case E2BIG:
return G_SPAWN_ERROR_2BIG;
break;
#endif
#ifdef ENOEXEC
case ENOEXEC:
return G_SPAWN_ERROR_NOEXEC;
break;
#endif
#ifdef ENAMETOOLONG
case ENAMETOOLONG:
return G_SPAWN_ERROR_NAMETOOLONG;
break;
#endif
#ifdef ENOENT
case ENOENT:
return G_SPAWN_ERROR_NOENT;
break;
#endif
#ifdef ENOMEM
case ENOMEM:
return G_SPAWN_ERROR_NOMEM;
break;
#endif
#ifdef ENOTDIR
case ENOTDIR:
return G_SPAWN_ERROR_NOTDIR;
break;
#endif
#ifdef ELOOP
case ELOOP:
return G_SPAWN_ERROR_LOOP;
break;
#endif
#ifdef ETXTBUSY
case ETXTBUSY:
return G_SPAWN_ERROR_TXTBUSY;
break;
#endif
#ifdef EIO
case EIO:
return G_SPAWN_ERROR_IO;
break;
#endif
#ifdef ENFILE
case ENFILE:
return G_SPAWN_ERROR_NFILE;
break;
#endif
#ifdef EMFILE
case EMFILE:
return G_SPAWN_ERROR_MFILE;
break;
#endif
#ifdef EINVAL
case EINVAL:
return G_SPAWN_ERROR_INVAL;
break;
#endif
#ifdef EISDIR
case EISDIR:
return G_SPAWN_ERROR_ISDIR;
break;
#endif
#ifdef ELIBBAD
case ELIBBAD:
return G_SPAWN_ERROR_LIBBAD;
break;
#endif
default:
return G_SPAWN_ERROR_FAILED;
break;
}
}
static void
write_err_and_exit (gint fd, gint msg)
{
gint en = errno;
write (fd, &msg, sizeof(msg));
write (fd, &en, sizeof(en));
_exit (1);
}
static void
set_cloexec (gint fd)
{
fcntl (fd, F_SETFD, FD_CLOEXEC);
}
static gint
sane_dup2 (gint fd1, gint fd2)
{
gint ret;
retry:
ret = dup2 (fd1, fd2);
if (ret < 0 && errno == EINTR)
goto retry;
return ret;
}
enum
{
CHILD_CHDIR_FAILED,
CHILD_EXEC_FAILED,
CHILD_DUP2_FAILED,
CHILD_FORK_FAILED
};
static void
do_exec (gint child_err_report_fd,
gint stdin_fd,
gint stdout_fd,
gint stderr_fd,
const gchar *working_directory,
gchar **argv,
gchar **envp,
gboolean close_descriptors,
gboolean search_path,
gboolean stdout_to_null,
gboolean stderr_to_null,
gboolean child_inherits_stdin,
GSpawnChildSetupFunc child_setup,
gpointer user_data)
{
if (working_directory && chdir (working_directory) < 0)
write_err_and_exit (child_err_report_fd,
CHILD_CHDIR_FAILED);
/* Close all file descriptors but stdin stdout and stderr as
* soon as we exec. Note that this includes
* child_err_report_fd, which keeps the parent from blocking
* forever on the other end of that pipe.
*/
if (close_descriptors)
{
gint open_max;
gint i;
open_max = sysconf (_SC_OPEN_MAX);
for (i = 3; i < open_max; i++)
set_cloexec (i);
}
else
{
/* We need to do child_err_report_fd anyway */
set_cloexec (child_err_report_fd);
}
/* Redirect pipes as required */
if (stdin_fd >= 0)
{
/* dup2 can't actually fail here I don't think */
if (sane_dup2 (stdin_fd, 0) < 0)
write_err_and_exit (child_err_report_fd,
CHILD_DUP2_FAILED);
/* ignore this if it doesn't work */
close_and_invalidate (&stdin_fd);
}
else if (!child_inherits_stdin)
{
/* Keep process from blocking on a read of stdin */
gint read_null = open ("/dev/null", O_RDONLY);
sane_dup2 (read_null, 0);
close_and_invalidate (&read_null);
}
if (stdout_fd >= 0)
{
/* dup2 can't actually fail here I don't think */
if (sane_dup2 (stdout_fd, 1) < 0)
write_err_and_exit (child_err_report_fd,
CHILD_DUP2_FAILED);
/* ignore this if it doesn't work */
close_and_invalidate (&stdout_fd);
}
else if (stdout_to_null)
{
gint write_null = open ("/dev/null", O_WRONLY);
sane_dup2 (write_null, 1);
close_and_invalidate (&write_null);
}
if (stderr_fd >= 0)
{
/* dup2 can't actually fail here I don't think */
if (sane_dup2 (stderr_fd, 2) < 0)
write_err_and_exit (child_err_report_fd,
CHILD_DUP2_FAILED);
/* ignore this if it doesn't work */
close_and_invalidate (&stderr_fd);
}
else if (stderr_to_null)
{
gint write_null = open ("/dev/null", O_WRONLY);
sane_dup2 (write_null, 2);
close_and_invalidate (&write_null);
}
/* Call user function just before we exec */
if (child_setup)
{
(* child_setup) (user_data);
}
g_execute (argv[0], argv, envp, search_path);
/* Exec failed */
write_err_and_exit (child_err_report_fd,
CHILD_EXEC_FAILED);
}
static gboolean
read_ints (int fd,
gint* buf,
gint n_ints_in_buf,
gint *n_ints_read,
GError **error)
{
gint bytes = 0;
while (TRUE)
{
gint chunk;
if (bytes >= sizeof(gint)*2)
break; /* give up, who knows what happened, should not be
* possible.
*/
again:
chunk = read (fd,
((gchar*)buf) + bytes,
sizeof(gint)*n_ints_in_buf - bytes);
if (chunk < 0 && errno == EINTR)
goto again;
if (chunk < 0)
{
/* Some weird shit happened, bail out */
g_set_error (error,
G_SPAWN_ERROR,
G_SPAWN_ERROR_FAILED,
_("Failed to read from child pipe (%s)"),
g_strerror (errno));
return FALSE;
}
else if (chunk == 0)
break; /* EOF */
else
{
g_assert (chunk > 0);
bytes += chunk;
}
}
*n_ints_read = bytes/4;
return TRUE;
}
static gboolean
fork_exec_with_pipes (gboolean intermediate_child,
const gchar *working_directory,
gchar **argv,
gchar **envp,
gboolean close_descriptors,
gboolean search_path,
gboolean stdout_to_null,
gboolean stderr_to_null,
gboolean child_inherits_stdin,
GSpawnChildSetupFunc child_setup,
gpointer user_data,
gint *child_pid,
gint *standard_input,
gint *standard_output,
gint *standard_error,
GError **error)
{
gint pid;
gint stdin_pipe[2] = { -1, -1 };
gint stdout_pipe[2] = { -1, -1 };
gint stderr_pipe[2] = { -1, -1 };
gint child_err_report_pipe[2] = { -1, -1 };
gint child_pid_report_pipe[2] = { -1, -1 };
gint status;
if (!make_pipe (child_err_report_pipe, error))
return FALSE;
if (intermediate_child && !make_pipe (child_pid_report_pipe, error))
goto cleanup_and_fail;
if (standard_input && !make_pipe (stdin_pipe, error))
goto cleanup_and_fail;
if (standard_output && !make_pipe (stdout_pipe, error))
goto cleanup_and_fail;
if (standard_error && !make_pipe (stderr_pipe, error))
goto cleanup_and_fail;
pid = fork ();
if (pid < 0)
{
g_set_error (error,
G_SPAWN_ERROR,
G_SPAWN_ERROR_FORK,
_("Failed to fork (%s)"),
g_strerror (errno));
goto cleanup_and_fail;
}
else if (pid == 0)
{
/* Immediate child. This may or may not be the child that
* actually execs the new process.
*/
/* Be sure we crash if the parent exits
* and we write to the err_report_pipe
*/
signal (SIGPIPE, SIG_DFL);
/* Close the parent's end of the pipes;
* not needed in the close_descriptors case,
* though
*/
close_and_invalidate (&child_err_report_pipe[0]);
close_and_invalidate (&child_pid_report_pipe[0]);
close_and_invalidate (&stdin_pipe[1]);
close_and_invalidate (&stdout_pipe[0]);
close_and_invalidate (&stderr_pipe[0]);
if (intermediate_child)
{
/* We need to fork an intermediate child that launches the
* final child. The purpose of the intermediate child
* is to exit, so we can waitpid() it immediately.
* Then the grandchild will not become a zombie.
*/
gint grandchild_pid;
grandchild_pid = fork ();
if (grandchild_pid < 0)
{
/* report -1 as child PID */
write (child_pid_report_pipe[1], &grandchild_pid,
sizeof(grandchild_pid));
write_err_and_exit (child_err_report_pipe[1],
CHILD_FORK_FAILED);
}
else if (grandchild_pid == 0)
{
do_exec (child_err_report_pipe[1],
stdin_pipe[0],
stdout_pipe[1],
stderr_pipe[1],
working_directory,
argv,
envp,
close_descriptors,
search_path,
stdout_to_null,
stderr_to_null,
child_inherits_stdin,
child_setup,
user_data);
}
else
{
write (child_pid_report_pipe[1], &grandchild_pid, sizeof(grandchild_pid));
close_and_invalidate (&child_pid_report_pipe[1]);
_exit (0);
}
}
else
{
/* Just run the child.
*/
do_exec (child_err_report_pipe[1],
stdin_pipe[0],
stdout_pipe[1],
stderr_pipe[1],
working_directory,
argv,
envp,
close_descriptors,
search_path,
stdout_to_null,
stderr_to_null,
child_inherits_stdin,
child_setup,
user_data);
}
}
else
{
/* Parent */
gint buf[2];
gint n_ints = 0;
/* Close the uncared-about ends of the pipes */
close_and_invalidate (&child_err_report_pipe[1]);
close_and_invalidate (&child_pid_report_pipe[1]);
close_and_invalidate (&stdin_pipe[0]);
close_and_invalidate (&stdout_pipe[1]);
close_and_invalidate (&stderr_pipe[1]);
/* If we had an intermediate child, reap it */
if (intermediate_child)
{
wait_again:
if (waitpid (pid, &status, 0) < 0)
{
if (errno == EINTR)
goto wait_again;
else if (errno == ECHILD)
; /* do nothing, child already reaped */
else
g_warning ("waitpid() should not fail in "
"'fork_exec_with_pipes'");
}
}
if (!read_ints (child_err_report_pipe[0],
buf, 2, &n_ints,
error))
goto cleanup_and_fail;
if (n_ints >= 2)
{
/* Error from the child. */
switch (buf[0])
{
case CHILD_CHDIR_FAILED:
g_set_error (error,
G_SPAWN_ERROR,
G_SPAWN_ERROR_CHDIR,
_("Failed to change to directory '%s' (%s)"),
working_directory,
g_strerror (buf[1]));
break;
case CHILD_EXEC_FAILED:
g_set_error (error,
G_SPAWN_ERROR,
exec_err_to_g_error (buf[1]),
_("Failed to execute child process (%s)"),
g_strerror (buf[1]));
break;
case CHILD_DUP2_FAILED:
g_set_error (error,
G_SPAWN_ERROR,
G_SPAWN_ERROR_FAILED,
_("Failed to redirect output or input of child process (%s)"),
g_strerror (buf[1]));
break;
case CHILD_FORK_FAILED:
g_set_error (error,
G_SPAWN_ERROR,
G_SPAWN_ERROR_FORK,
_("Failed to fork child process (%s)"),
g_strerror (buf[1]));
break;
default:
g_set_error (error,
G_SPAWN_ERROR,
G_SPAWN_ERROR_FAILED,
_("Unknown error executing child process"));
break;
}
goto cleanup_and_fail;
}
/* Get child pid from intermediate child pipe. */
if (intermediate_child)
{
n_ints = 0;
if (!read_ints (child_pid_report_pipe[0],
buf, 1, &n_ints, error))
goto cleanup_and_fail;
if (n_ints < 1)
{
g_set_error (error,
G_SPAWN_ERROR,
G_SPAWN_ERROR_FAILED,
_("Failed to read enough data from child pid pipe (%s)"),
g_strerror (errno));
goto cleanup_and_fail;
}
else
{
/* we have the child pid */
pid = buf[0];
}
}
/* Success against all odds! return the information */
if (child_pid)
*child_pid = pid;
if (standard_input)
*standard_input = stdin_pipe[1];
if (standard_output)
*standard_output = stdout_pipe[0];
if (standard_error)
*standard_error = stderr_pipe[0];
return TRUE;
}
cleanup_and_fail:
close_and_invalidate (&child_err_report_pipe[0]);
close_and_invalidate (&child_err_report_pipe[1]);
close_and_invalidate (&child_pid_report_pipe[0]);
close_and_invalidate (&child_pid_report_pipe[1]);
close_and_invalidate (&stdin_pipe[0]);
close_and_invalidate (&stdin_pipe[1]);
close_and_invalidate (&stdout_pipe[0]);
close_and_invalidate (&stdout_pipe[1]);
close_and_invalidate (&stderr_pipe[0]);
close_and_invalidate (&stderr_pipe[1]);
return FALSE;
}
static gboolean
make_pipe (gint p[2],
GError **error)
{
if (pipe (p) < 0)
{
g_set_error (error,
G_SPAWN_ERROR,
G_SPAWN_ERROR_FAILED,
_("Failed to create pipe for communicating with child process (%s)"),
g_strerror (errno));
return FALSE;
}
else
return TRUE;
}
/* Based on execvp from GNU C Library */
static void
script_execute (const gchar *file,
gchar **argv,
gchar **envp,
gboolean search_path)
{
/* Count the arguments. */
int argc = 0;
while (argv[argc])
++argc;
/* Construct an argument list for the shell. */
{
gchar **new_argv;
new_argv = g_new0 (gchar*, argc + 1);
new_argv[0] = (char *) "/bin/sh";
new_argv[1] = (char *) file;
while (argc > 1)
{
new_argv[argc] = argv[argc - 1];
--argc;
}
/* Execute the shell. */
if (envp)
execve (new_argv[0], new_argv, envp);
else
execv (new_argv[0], new_argv);
g_free (new_argv);
}
}
static gchar*
my_strchrnul (const gchar *str, gchar c)
{
gchar *p = (gchar*) str;
while (*p && (*p != c))
++p;
return p;
}
static gint
g_execute (const gchar *file,
gchar **argv,
gchar **envp,
gboolean search_path)
{
if (*file == '\0')
{
/* We check the simple case first. */
errno = ENOENT;
return -1;
}
if (!search_path || strchr (file, '/') != NULL)
{
/* Don't search when it contains a slash. */
if (envp)
execve (file, argv, envp);
else
execv (file, argv);
if (errno == ENOEXEC)
script_execute (file, argv, envp, FALSE);
}
else
{
gboolean got_eacces = 0;
char *path, *p, *name, *freeme;
size_t len;
size_t pathlen;
path = g_getenv ("PATH");
if (path == NULL)
{
/* There is no `PATH' in the environment. The default
* search path in libc is the current directory followed by
* the path `confstr' returns for `_CS_PATH'.
*/
/* In GLib we put . last, for security, and don't use the
* unportable confstr(); UNIX98 does not actually specify
* what to search if PATH is unset. POSIX may, dunno.
*/
path = "/bin:/usr/bin:.";
}
len = strlen (file) + 1;
pathlen = strlen (path);
freeme = name = g_malloc (pathlen + len + 1);
/* Copy the file name at the top, including '\0' */
memcpy (name + pathlen + 1, file, len);
name = name + pathlen;
/* And add the slash before the filename */
*name = '/';
p = path;
do
{
char *startp;
path = p;
p = my_strchrnul (path, ':');
if (p == path)
/* Two adjacent colons, or a colon at the beginning or the end
* of `PATH' means to search the current directory.
*/
startp = name + 1;
else
startp = memcpy (name - (p - path), path, p - path);
/* Try to execute this name. If it works, execv will not return. */
if (envp)
execve (startp, argv, envp);
else
execv (startp, argv);
if (errno == ENOEXEC)
script_execute (startp, argv, envp, search_path);
switch (errno)
{
case EACCES:
/* Record the we got a `Permission denied' error. If we end
* up finding no executable we can use, we want to diagnose
* that we did find one but were denied access.
*/
got_eacces = TRUE;
/* FALL THRU */
case ENOENT:
#ifdef ESTALE
case ESTALE:
#endif
#ifdef ENOTDIR
case ENOTDIR:
#endif
/* Those errors indicate the file is missing or not executable
* by us, in which case we want to just try the next path
* directory.
*/
break;
default:
/* Some other error means we found an executable file, but
* something went wrong executing it; return the error to our
* caller.
*/
g_free (freeme);
return -1;
}
}
while (*p++ != '\0');
/* We tried every element and none of them worked. */
if (got_eacces)
/* At least one failure was due to permissions, so report that
* error.
*/
errno = EACCES;
g_free (freeme);
}
/* Return the error from the last attempt (probably ENOENT). */
return -1;
}
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