#include "gspawn.h"
#include "gthread.h"
+#include "glib/gstdio.h"
#include "genviron.h"
#include "gmem.h"
-#include "gmain.h"
#include "gshell.h"
#include "gstring.h"
#include "gstrfuncs.h"
* SECTION:spawn
* @Short_description: process launching
* @Title: Spawning Processes
+ *
+ * GLib supports spawning of processes with an API that is more
+ * convenient than the bare UNIX fork() and exec().
+ *
+ * The g_spawn family of functions has synchronous (g_spawn_sync())
+ * and asynchronous variants (g_spawn_async(), g_spawn_async_with_pipes()),
+ * as well as convenience variants that take a complete shell-like
+ * commandline (g_spawn_command_line_sync(), g_spawn_command_line_async()).
+ *
+ * See #GSubprocess in GIO for a higher-level API that provides
+ * stream interfaces for communication with child processes.
*/
* You should call g_spawn_close_pid() on the returned child process
* reference when you don't need it any more.
*
- * <note><para>
- * If you are writing a GTK+ application, and the program you
- * are spawning is a graphical application, too, then you may
- * want to use gdk_spawn_on_screen() instead to ensure that
- * the spawned program opens its windows on the right screen.
- * </para></note>
+ * If you are writing a GTK+ application, and the program you are
+ * spawning is a graphical application, too, then you may want to
+ * use gdk_spawn_on_screen() instead to ensure that the spawned program
+ * opens its windows on the right screen.
*
- * <note><para> Note that the returned @child_pid on Windows is a
- * handle to the child process and not its identifier. Process handles
- * and process identifiers are different concepts on Windows.
- * </para></note>
+ * Note that the returned @child_pid on Windows is a handle to the child
+ * process and not its identifier. Process handles and process identifiers
+ * are different concepts on Windows.
*
- * Return value: %TRUE on success, %FALSE if error is set
+ * Returns: %TRUE on success, %FALSE if error is set
**/
gboolean
g_spawn_async (const gchar *working_directory,
* on a file descriptor twice, and another thread has
* re-opened it since the first close)
*/
-static gint
+static void
close_and_invalidate (gint *fd)
{
- gint ret;
-
if (*fd < 0)
- return -1;
+ return;
else
{
- again:
- ret = close (*fd);
- if (ret == -1 && errno == EINTR)
- goto again;
+ (void) g_close (*fd, NULL);
*fd = -1;
}
-
- return ret;
}
/* Some versions of OS X define READ_OK in public headers */
}
}
-typedef struct {
- GMainLoop *loop;
- gint *status_p;
-} SyncWaitpidData;
-
-static void
-on_sync_waitpid (GPid pid,
- gint status,
- gpointer user_data)
-{
- SyncWaitpidData *data = user_data;
- *(data->status_p) = status;
- g_main_loop_quit (data->loop);
-}
-
/**
* g_spawn_sync:
* @working_directory: (allow-none): child's current working directory, or %NULL to inherit parent's
* passing %NULL for @standard_output and @standard_error.
*
* If @exit_status is non-%NULL, the platform-specific exit status of
- * the child is stored there; see the doucumentation of
+ * the child is stored there; see the documentation of
* g_spawn_check_exit_status() for how to use and interpret this.
* Note that it is invalid to pass %G_SPAWN_DO_NOT_REAP_CHILD in
* @flags.
* function for full details on the other parameters and details on
* how these functions work on Windows.
*
- * Return value: %TRUE on success, %FALSE if an error was set.
- **/
+ * Returns: %TRUE on success, %FALSE if an error was set
+ */
gboolean
g_spawn_sync (const gchar *working_directory,
gchar **argv,
GString *errstr = NULL;
gboolean failed;
gint status;
- SyncWaitpidData waitpid_data;
g_return_val_if_fail (argv != NULL, FALSE);
g_return_val_if_fail (!(flags & G_SPAWN_DO_NOT_REAP_CHILD), FALSE);
close_and_invalidate (&outpipe);
if (errpipe >= 0)
close_and_invalidate (&errpipe);
-
- /* Now create a temporary main context and loop, with just one
- * waitpid source. We used to invoke waitpid() directly here, but
- * this way we unify with the worker thread in gmain.c.
+
+ /* Wait for child to exit, even if we have
+ * an error pending.
*/
- {
- GMainContext *context;
- GMainLoop *loop;
- GSource *source;
-
- context = g_main_context_new ();
- loop = g_main_loop_new (context, TRUE);
+ again:
+
+ ret = waitpid (pid, &status, 0);
- waitpid_data.loop = loop;
- waitpid_data.status_p = &status;
-
- source = g_child_watch_source_new (pid);
- g_source_set_callback (source, (GSourceFunc)on_sync_waitpid, &waitpid_data, NULL);
- g_source_attach (source, context);
- g_source_unref (source);
-
- g_main_loop_run (loop);
+ 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 ECHILD was received by waitpid(). Most likely the process is ignoring SIGCHLD, or some other thread is invoking waitpid() with a nonpositive first argument; either behavior can break applications that use g_spawn_sync either directly or indirectly.");
+ }
+ else
+ {
+ /* We don't need the exit status. */
+ }
+ }
+ else
+ {
+ if (!failed) /* avoid error pileups */
+ {
+ int errsv = errno;
- g_main_context_unref (context);
- g_main_loop_unref (loop);
- }
+ failed = TRUE;
+
+ g_set_error (error,
+ G_SPAWN_ERROR,
+ G_SPAWN_ERROR_READ,
+ _("Unexpected error in waitpid() (%s)"),
+ g_strerror (errsv));
+ }
+ }
+ }
if (failed)
{
*
* 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. If @flags contains the
- * %G_SPAWN_SEARCH_PATH flag, the <envar>PATH</envar> environment variable
- * is used to search for the executable. If @flags contains the
- * %G_SPAWN_SEARCH_PATH_FROM_ENVP flag, the <envar>PATH</envar> variable from
- * @envp is used to search for the executable.
- * If both the %G_SPAWN_SEARCH_PATH and %G_SPAWN_SEARCH_PATH_FROM_ENVP
- * flags are set, the <envar>PATH</envar> variable from @envp takes precedence
- * over the environment variable.
+ * 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. If @flags contains the
+ * %G_SPAWN_SEARCH_PATH flag, the `PATH` environment variable is
+ * used to search for the executable. If @flags contains the
+ * %G_SPAWN_SEARCH_PATH_FROM_ENVP flag, the `PATH` variable from
+ * @envp is used to search for the executable. If both the
+ * %G_SPAWN_SEARCH_PATH and %G_SPAWN_SEARCH_PATH_FROM_ENVP flags
+ * are set, the `PATH` variable from @envp takes precedence over
+ * the environment variable.
*
* If the program name is not a full path and %G_SPAWN_SEARCH_PATH flag is not
* used, then the program will be run from the current directory (or
* level wide character command line passed to the spawned program
* using the GetCommandLineW() function.
*
- * On Windows the low-level child process creation API
- * <function>CreateProcess()</function> doesn't use argument vectors,
- * but a command line. The C runtime library's
- * <function>spawn*()</function> family of functions (which
- * g_spawn_async_with_pipes() eventually calls) paste the argument
- * vector elements together into a command line, and the C runtime startup code
- * does a corresponding reconstruction of an argument vector from the
- * command line, to be passed to main(). Complications arise when you have
- * argument vector elements that contain spaces of double quotes. The
- * <function>spawn*()</function> functions don't do any quoting or
- * escaping, but on the other hand the startup code does do unquoting
- * and unescaping in order to enable receiving arguments with embedded
- * spaces or double quotes. To work around this asymmetry,
- * g_spawn_async_with_pipes() will do quoting and escaping on argument
- * vector elements that need it before calling the C runtime
+ * On Windows the low-level child process creation API CreateProcess()
+ * doesn't use argument vectors, but a command line. The C runtime
+ * library's spawn*() family of functions (which g_spawn_async_with_pipes()
+ * eventually calls) paste the argument vector elements together into
+ * a command line, and the C runtime startup code does a corresponding
+ * reconstruction of an argument vector from the command line, to be
+ * passed to main(). Complications arise when you have argument vector
+ * elements that contain spaces of double quotes. The spawn*() functions
+ * don't do any quoting or escaping, but on the other hand the startup
+ * code does do unquoting and unescaping in order to enable receiving
+ * arguments with embedded spaces or double quotes. To work around this
+ * asymmetry, g_spawn_async_with_pipes() will do quoting and escaping on
+ * argument vector elements that need it before calling the C runtime
* spawn() function.
*
* The returned @child_pid on Windows is a handle to the child
* identifiers are different concepts on Windows.
*
* @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.
+ * has the form `KEY=VALUE`. 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 behaviour. The %G_SPAWN_DO_NOT_REAP_CHILD means that the
* call g_spawn_close_pid() on the @child_pid, in order to free
* resources which may be associated with the child process. (On Unix,
* using a child watch is equivalent to calling waitpid() or handling
- * the <literal>SIGCHLD</literal> signal manually. On Windows, calling g_spawn_close_pid()
+ * the %SIGCHLD signal manually. On Windows, calling g_spawn_close_pid()
* is equivalent to calling CloseHandle() on the process handle returned
- * in @child_pid). See g_child_watch_add().
+ * in @child_pid). See g_child_watch_add().
*
* %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 <envar>PATH</envar> environment variable.
- * %G_SPAWN_SEARCH_PATH_FROM_ENVP means need not be an absolute path, it
- * will be looked for in the <envar>PATH</envar> variable from @envp. If
- * both %G_SPAWN_SEARCH_PATH and %G_SPAWN_SEARCH_PATH_FROM_ENVP are used,
- * the value from @envp takes precedence over the environment.
- * %G_SPAWN_STDOUT_TO_DEV_NULL means that the child's standard output will
- * be discarded, instead of going to the same location as the parent's
+ * 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 @argv[0] need not be an
+ * absolute path, it will be looked for in the `PATH` environment
+ * variable. %G_SPAWN_SEARCH_PATH_FROM_ENVP means need not be an
+ * absolute path, it will be looked for in the `PATH` variable from
+ * @envp. If both %G_SPAWN_SEARCH_PATH and %G_SPAWN_SEARCH_PATH_FROM_ENVP
+ * are used, the value from @envp takes precedence over the environment.
+ * %G_SPAWN_STDOUT_TO_DEV_NULL means that the child's standard output
+ * will be discarded, instead of going to the same location as the parent's
* standard output. If you use this flag, @standard_output must be %NULL.
* %G_SPAWN_STDERR_TO_DEV_NULL means that the child's standard error
* will be discarded, instead of going to the same location as the parent's
* standard input (by default, the child's standard input is attached to
* /dev/null). If you use this flag, @standard_input must be %NULL.
* %G_SPAWN_FILE_AND_ARGV_ZERO means that the first element of @argv is
- * the file to execute, while the remaining elements are the
- * actual argument vector to pass to the file. Normally
- * g_spawn_async_with_pipes() uses @argv[0] as the file to execute, and
- * passes all of @argv to the child.
+ * the file to execute, while the remaining elements are the actual
+ * argument vector to pass to the file. Normally g_spawn_async_with_pipes()
+ * uses @argv[0] as the file to execute, and passes all of @argv to the child.
*
* @child_setup and @user_data are a function and user data. On POSIX
* platforms, the function is 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.
+ * 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.
*
- * On Windows, there is no separate fork() and exec()
- * functionality. Child processes are created and run with a single
- * API call, CreateProcess(). There is no sensible thing @child_setup
+ * On Windows, there is no separate fork() and exec() functionality.
+ * Child processes are created and run with a single API call,
+ * CreateProcess(). There is no sensible thing @child_setup
* could be used for on Windows so it is ignored and not called.
*
* If non-%NULL, @child_pid will on Unix be filled with the child's
- * process ID. You can use the process ID to send signals to the
- * child, or to use g_child_watch_add() (or waitpid()) if you specified the
+ * process ID. You can use the process ID to send signals to the child,
+ * or to use g_child_watch_add() (or waitpid()) if you specified the
* %G_SPAWN_DO_NOT_REAP_CHILD flag. On Windows, @child_pid will be
* filled with a handle to the child process only if you specified the
* %G_SPAWN_DO_NOT_REAP_CHILD flag. You can then access the child
* process using the Win32 API, for example wait for its termination
- * with the <function>WaitFor*()</function> functions, or examine its
- * exit code with GetExitCodeProcess(). You should close the handle
- * with CloseHandle() or g_spawn_close_pid() when you no longer need it.
+ * with the WaitFor*() functions, or examine its exit code with
+ * GetExitCodeProcess(). You should close the handle with CloseHandle()
+ * or g_spawn_close_pid() when you no longer need it.
*
* 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.
+ * when they are no longer in use. If these parameters are %NULL, the
+ * corresponding pipe won't be created.
*
* If @standard_input is NULL, the child's standard input is attached to
* /dev/null unless %G_SPAWN_CHILD_INHERITS_STDIN is set.
* is set.
*
* @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 is set, the function returns %FALSE. Errors are reported
+ * even if they occur in the child (for example if the executable in
+ * @argv[0] is not found). Typically the `message` 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.
* If @child_pid is not %NULL and an error does not occur then the returned
* process reference must be closed using g_spawn_close_pid().
*
- * <note><para>
* If you are writing a GTK+ application, and the program you
* are spawning is a graphical application, too, then you may
* want to use gdk_spawn_on_screen_with_pipes() instead to ensure that
* the spawned program opens its windows on the right screen.
- * </para></note>
*
- * Return value: %TRUE on success, %FALSE if an error was set
- **/
+ * Returns: %TRUE on success, %FALSE if an error was set
+ */
gboolean
g_spawn_async_with_pipes (const gchar *working_directory,
gchar **argv,
* separator. You need to enclose such paths with single quotes, like
* "'c:\\program files\\app\\app.exe' 'e:\\folder\\argument.txt'".
*
- * Return value: %TRUE on success, %FALSE if an error was set
+ * Returns: %TRUE on success, %FALSE if an error was set
**/
gboolean
g_spawn_command_line_sync (const gchar *command_line,
*
* The same concerns on Windows apply as for g_spawn_command_line_sync().
*
- * Return value: %TRUE on success, %FALSE if error is set.
+ * Returns: %TRUE on success, %FALSE if error is set
**/
gboolean
g_spawn_command_line_async (const gchar *command_line,
*
* The g_spawn_sync() and g_child_watch_add() family of APIs return an
* exit status for subprocesses encoded in a platform-specific way.
- * On Unix, this is guaranteed to be in the same format
- * <literal>waitpid(2)</literal> returns, and on Windows it is
- * guaranteed to be the result of
- * <literal>GetExitCodeProcess()</literal>. Prior to the introduction
- * of this function in GLib 2.34, interpreting @exit_status required
- * use of platform-specific APIs, which is problematic for software
- * using GLib as a cross-platform layer.
+ * On Unix, this is guaranteed to be in the same format waitpid() returns,
+ * and on Windows it is guaranteed to be the result of GetExitCodeProcess().
+ *
+ * Prior to the introduction of this function in GLib 2.34, interpreting
+ * @exit_status required use of platform-specific APIs, which is problematic
+ * for software using GLib as a cross-platform layer.
*
* Additionally, many programs simply want to determine whether or not
* the child exited successfully, and either propagate a #GError or
- * print a message to standard error. In that common case, this
- * function can be used. Note that the error message in @error will
- * contain human-readable information about the exit status.
+ * print a message to standard error. In that common case, this function
+ * can be used. Note that the error message in @error will contain
+ * human-readable information about the exit status.
*
- * The <literal>domain</literal> and <literal>code</literal> of @error
- * have special semantics in the case where the process has an "exit
- * code", as opposed to being killed by a signal. On Unix, this
- * happens if <literal>WIFEXITED</literal> would be true of
- * @exit_status. On Windows, it is always the case.
+ * The @domain and @code of @error have special semantics in the case
+ * where the process has an "exit code", as opposed to being killed by
+ * a signal. On Unix, this happens if WIFEXITED() would be true of
+ * @exit_status. On Windows, it is always the case.
*
* The special semantics are that the actual exit code will be the
* code set in @error, and the domain will be %G_SPAWN_EXIT_ERROR.
*
* This function just offers convenience; you can of course also check
* the available platform via a macro such as %G_OS_UNIX, and use
- * <literal>WIFEXITED()</literal> and <literal>WEXITSTATUS()</literal>
- * on @exit_status directly. Do not attempt to scan or parse the
- * error message string; it may be translated and/or change in future
- * versions of GLib.
+ * WIFEXITED() and WEXITSTATUS() on @exit_status directly. Do not attempt
+ * to scan or parse the error message string; it may be translated and/or
+ * change in future versions of GLib.
+ *
+ * Returns: %TRUE if child exited successfully, %FALSE otherwise (and
+ * @error will be set)
*
- * Returns: %TRUE if child exited successfully, %FALSE otherwise (and @error will be set)
* Since: 2.34
*/
gboolean
}
else if (grandchild_pid == 0)
{
+ close_and_invalidate (&child_pid_report_pipe[1]);
do_exec (child_err_report_pipe[1],
stdin_pipe[0],
stdout_pipe[1],
if (path == NULL)
{
- /* There is no `PATH' in the environment. The default
+ /* 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'.
+ * the path 'confstr' returns for '_CS_PATH'.
*/
/* In GLib we put . last, for security, and don't use the
if (p == path)
/* Two adjacent colons, or a colon at the beginning or the end
- * of `PATH' means to search the current directory.
+ * of 'PATH' means to search the current directory.
*/
startp = name + 1;
else
switch (errno)
{
case EACCES:
- /* Record the we got a `Permission denied' error. If we end
+ /* 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.
*/
projects / platform / upstream / glib.git / blobdiff