glib/glib-unix.h - third_party/glib - Git at Google

 /* glib-unix.h - Unix specific integration
  * Copyright (C) 2011 Red Hat, Inc.
  * Copyright 2023 Collabora Ltd.
  *
  * SPDX-License-Identifier: LGPL-2.1-or-later
  *
  * This library 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 2.1 of the License, or (at your option) any later version.
  *
  * This library 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 this library; if not, see <http://www.gnu.org/licenses/>.
  */

 #ifndef __G_UNIX_H__
 #define __G_UNIX_H__

 /* We need to include the UNIX headers needed to use the APIs below,
  * but we also take this opportunity to include a wide selection of
  * other UNIX headers.  If one of the headers below is broken on some
  * system, work around it here (or better, fix the system or tell
  * people to use a better one).
  */
 #include <unistd.h>
 #include <errno.h>
 #include <sys/wait.h>
 #include <stdlib.h>
 #include <fcntl.h>

 #include <glib.h>
 #include <glib/gstdio.h>

 #ifndef G_OS_UNIX
 #error "This header may only be used on UNIX"
 #endif

 G_BEGIN_DECLS

 /**
  * G_UNIX_ERROR:
  *
  * Error domain for API in the g_unix_ namespace. Note that there is no
  * exported enumeration mapping %errno. Instead, all functions ensure that
  * %errno is relevant. The code for all %G_UNIX_ERROR is always 0, and the
  * error message is always generated via g_strerror().
  *
  * It is expected that most code will not look at %errno from these APIs.
  * Important cases where one would want to differentiate between errors are
  * already covered by existing cross-platform GLib API, such as e.g. #GFile
  * wrapping `ENOENT`. However, it is provided for completeness, at least.
  */
 #define G_UNIX_ERROR (g_unix_error_quark())

 GLIB_AVAILABLE_IN_2_30
 GQuark g_unix_error_quark (void);

 GLIB_AVAILABLE_IN_2_30
 gboolean g_unix_open_pipe (gint    *fds,
                            gint     flags,
                            GError **error);

 GLIB_AVAILABLE_IN_2_30
 gboolean g_unix_set_fd_nonblocking (gint       fd,
                                     gboolean   nonblock,
                                     GError   **error);

 GLIB_AVAILABLE_IN_2_30
 GSource *g_unix_signal_source_new  (gint signum);

 GLIB_AVAILABLE_IN_2_30
 guint    g_unix_signal_add_full    (gint           priority,
                                     gint           signum,
                                     GSourceFunc    handler,
                                     gpointer       user_data,
                                     GDestroyNotify notify);

 GLIB_AVAILABLE_IN_2_30
 guint    g_unix_signal_add         (gint        signum,
                                     GSourceFunc handler,
                                     gpointer    user_data);

 /**
  * GUnixFDSourceFunc:
  * @fd: the fd that triggered the event
  * @condition: the IO conditions reported on @fd
  * @user_data: user data passed to g_unix_fd_add()
  *
  * The type of functions to be called when a UNIX fd watch source
  * triggers.
  *
  * Returns: %FALSE if the source should be removed
  **/
 typedef gboolean (*GUnixFDSourceFunc) (gint         fd,
                                        GIOCondition condition,
                                        gpointer     user_data);

 GLIB_AVAILABLE_IN_2_36
 GSource *g_unix_fd_source_new      (gint         fd,
                                     GIOCondition condition);

 GLIB_AVAILABLE_IN_2_36
 guint    g_unix_fd_add_full        (gint              priority,
                                     gint              fd,
                                     GIOCondition      condition,
                                     GUnixFDSourceFunc function,
                                     gpointer          user_data,
                                     GDestroyNotify    notify);

 GLIB_AVAILABLE_IN_2_36
 guint    g_unix_fd_add             (gint              fd,
                                     GIOCondition      condition,
                                     GUnixFDSourceFunc function,
                                     gpointer          user_data);

 GLIB_AVAILABLE_IN_2_64
 struct passwd *g_unix_get_passwd_entry (const gchar  *user_name,
                                         GError      **error);

 /**
  * GUnixPipe:
  * @fds: A pair of file descriptors, each negative if closed or not yet opened.
  *  The file descriptor with index %G_UNIX_PIPE_END_READ is readable.
  *  The file descriptor with index %G_UNIX_PIPE_END_WRITE is writable.
  *
  * A Unix pipe. The advantage of this type over `int[2]` is that it can
  * be closed automatically when it goes out of scope, using `g_auto(GUnixPipe)`,
  * on compilers that support that feature.
  *
  * Since: 2.80
  */
 GLIB_AVAILABLE_TYPE_IN_2_80
 typedef struct {
   int fds[2];
 } GUnixPipe;

 /**
  * GUnixPipeEnd:
  * @G_UNIX_PIPE_END_READ: The readable file descriptor 0
  * @G_UNIX_PIPE_END_WRITE: The writable file descriptor 1
  *
  * Mnemonic constants for the ends of a Unix pipe.
  *
  * Since: 2.80
  */
 GLIB_AVAILABLE_TYPE_IN_2_80
 typedef enum
 {
   G_UNIX_PIPE_END_READ = 0,
   G_UNIX_PIPE_END_WRITE = 1
 } GUnixPipeEnd;

 /**
  * G_UNIX_PIPE_INIT:
  *
  * Initializer for a #GUnixPipe that has not yet been opened.
  * Both of its file descriptors are initialized to `-1` (invalid),
  * the same as if they had been closed.
  *
  * Since: 2.80
  */
 #define G_UNIX_PIPE_INIT { { -1, -1 } } GLIB_AVAILABLE_MACRO_IN_2_80

 /* Suppress "Not available before" warnings when declaring the
  * implementations */
 G_GNUC_BEGIN_IGNORE_DEPRECATIONS

 /**
  * g_unix_pipe_open:
  * @self: A pair of file descriptors
  * @flags: Flags to pass to g_unix_open_pipe(), typically `O_CLOEXEC`
  * @error: Used to report an error on failure
  *
  * Open a pipe. This is the same as g_unix_open_pipe(), but uses the
  * #GUnixPipe data structure.
  *
  * Returns: %TRUE on success
  *
  * Since: 2.80
  */
 GLIB_AVAILABLE_STATIC_INLINE_IN_2_80
 static inline gboolean
 g_unix_pipe_open (GUnixPipe *self,
                   int flags,
                   GError **error)
 {
   return g_unix_open_pipe (self->fds, flags, error);
 }

 /**
  * g_unix_pipe_get:
  * @self: A pair of file descriptors
  * @end: One of the ends of the pipe
  *
  * Return one of the ends of the pipe. It remains owned by @self.
  *
  * This function is async-signal safe (see [`signal(7)`](man:signal(7)) and
  * [`signal-safety(7)`](man:signal-safety(7))), making it safe to call from a
  * signal handler or a #GSpawnChildSetupFunc.
  *
  * This function preserves the value of `errno`.
  *
  * Returns: a non-negative file descriptor owned by @self, which must not
  *  be closed by the caller, or a negative number if the corresponding
  *  end of the pipe was already closed or stolen
  *
  * Since: 2.80
  */
 GLIB_AVAILABLE_STATIC_INLINE_IN_2_80
 static inline int
 g_unix_pipe_get (GUnixPipe *self,
                  GUnixPipeEnd end)
 {
   return self->fds[end];
 }

 /**
  * g_unix_pipe_steal:
  * @self: A pair of file descriptors
  * @end: One of the ends of the pipe
  *
  * Return one of the ends of the pipe. It becomes owned by the caller,
  * and the file descriptor in the data structure is set to `-1`,
  * similar to g_steal_fd().
  *
  * This function is async-signal safe (see [`signal(7)`](man:signal(7)) and
  * [`signal-safety(7)`](man:signal-safety(7))), making it safe to call from a
  * signal handler or a #GSpawnChildSetupFunc.
  *
  * This function preserves the value of `errno`.
  *
  * Returns: a non-negative file descriptor, which becomes owned by the
  *  caller and must be closed by the caller if required, or a negative
  *  number if the corresponding end of the pipe was already closed or stolen
  *
  * Since: 2.80
  */
 GLIB_AVAILABLE_STATIC_INLINE_IN_2_80
 static inline int
 g_unix_pipe_steal (GUnixPipe *self,
                    GUnixPipeEnd end)
 {
   return g_steal_fd (&self->fds[end]);
 }

 /**
  * g_unix_pipe_close:
  * @self: A pair of file descriptors
  * @end: One of the ends of the pipe
  * @error: Optionally used to report an error on failure
  *
  * Close one of the ends of the pipe and set the relevant member of @fds
  * to `-1` before returning, equivalent to g_clear_fd().
  *
  * Like g_close(), if closing the file descriptor fails, the error is
  * stored in both %errno and @error. If this function succeeds,
  * %errno is undefined.
  *
  * This function is async-signal safe if @error is %NULL and the relevant
  * member of @fds is either negative or a valid open file descriptor.
  * This makes it safe to call from a signal handler or a #GSpawnChildSetupFunc
  * under those conditions.
  * See [`signal(7)`](man:signal(7)) and
  * [`signal-safety(7)`](man:signal-safety(7)) for more details.
  *
  * To close both file descriptors and ignore any errors, use
  * g_unix_pipe_clear() instead.
  *
  * Returns: %TRUE on success
  *
  * Since: 2.80
  */
 GLIB_AVAILABLE_STATIC_INLINE_IN_2_80
 static inline gboolean
 g_unix_pipe_close (GUnixPipe *self,
                    GUnixPipeEnd end,
                    GError **error)
 {
   return g_clear_fd (&self->fds[end], error);
 }

 /**
  * g_unix_pipe_clear:
  * @self: a #GUnixPipe
  *
  * Close both ends of the pipe, unless they have already been closed or
  * stolen. Any errors are ignored: use g_unix_pipe_close() or g_clear_fd()
  * if error-handling is required.
  *
  * This function is async-signal safe if @error is %NULL and each member
  * of @fds are either negative or a valid open file descriptor.
  * As a result, it is safe to call this function or use `g_auto(GUnixPipe)`
  * (on compilers that support it) in a signal handler or a
  * #GSpawnChildSetupFunc, as long as those conditions are ensured to be true.
  * See [`signal(7)`](man:signal(7)) and
  * [`signal-safety(7)`](man:signal-safety(7)) for more details.
  *
  * This function preserves the value of `errno`.
  *
  * Since: 2.80
  */
 GLIB_AVAILABLE_STATIC_INLINE_IN_2_80
 static inline void
 g_unix_pipe_clear (GUnixPipe *self)
 {
   /* Don't overwrite thread-local errno if closing the fd fails */
   int errsv = errno;

   if (!g_unix_pipe_close (self, G_UNIX_PIPE_END_READ, NULL))
     {
       /* ignore */
     }

   if (!g_unix_pipe_close (self, G_UNIX_PIPE_END_WRITE, NULL))
     {
       /* ignore */
     }

   errno = errsv;
 }

 G_DEFINE_AUTO_CLEANUP_CLEAR_FUNC (GUnixPipe, g_unix_pipe_clear)

 GLIB_AVAILABLE_IN_2_80
 int g_closefrom (int lowfd);

 GLIB_AVAILABLE_IN_2_80
 int g_fdwalk_set_cloexec (int lowfd);

 G_GNUC_END_IGNORE_DEPRECATIONS

 G_END_DECLS

 #endif  /* __G_UNIX_H__ */
	/* glib-unix.h - Unix specific integration
	* Copyright (C) 2011 Red Hat, Inc.
	* Copyright 2023 Collabora Ltd.
	*
	* SPDX-License-Identifier: LGPL-2.1-or-later
	*
	* This library 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 2.1 of the License, or (at your option) any later version.
	*
	* This library 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 this library; if not, see <http://www.gnu.org/licenses/>.
	*/

	#ifndef __G_UNIX_H__
	#define __G_UNIX_H__

	/* We need to include the UNIX headers needed to use the APIs below,
	* but we also take this opportunity to include a wide selection of
	* other UNIX headers. If one of the headers below is broken on some
	* system, work around it here (or better, fix the system or tell
	* people to use a better one).
	*/
	#include <unistd.h>
	#include <errno.h>
	#include <sys/wait.h>
	#include <stdlib.h>
	#include <fcntl.h>

	#include <glib.h>
	#include <glib/gstdio.h>

	#ifndef G_OS_UNIX
	#error "This header may only be used on UNIX"
	#endif

	G_BEGIN_DECLS

	/**
	* G_UNIX_ERROR:
	*
	* Error domain for API in the g_unix_ namespace. Note that there is no
	* exported enumeration mapping %errno. Instead, all functions ensure that
	* %errno is relevant. The code for all %G_UNIX_ERROR is always 0, and the
	* error message is always generated via g_strerror().
	*
	* It is expected that most code will not look at %errno from these APIs.
	* Important cases where one would want to differentiate between errors are
	* already covered by existing cross-platform GLib API, such as e.g. #GFile
	* wrapping `ENOENT`. However, it is provided for completeness, at least.
	*/
	#define G_UNIX_ERROR (g_unix_error_quark())

	GLIB_AVAILABLE_IN_2_30
	GQuark g_unix_error_quark (void);

	GLIB_AVAILABLE_IN_2_30
	gboolean g_unix_open_pipe (gint *fds,
	gint flags,
	GError **error);

	GLIB_AVAILABLE_IN_2_30
	gboolean g_unix_set_fd_nonblocking (gint fd,
	gboolean nonblock,
	GError **error);

	GLIB_AVAILABLE_IN_2_30
	GSource *g_unix_signal_source_new (gint signum);

	GLIB_AVAILABLE_IN_2_30
	guint g_unix_signal_add_full (gint priority,
	gint signum,
	GSourceFunc handler,
	gpointer user_data,
	GDestroyNotify notify);

	GLIB_AVAILABLE_IN_2_30
	guint g_unix_signal_add (gint signum,
	GSourceFunc handler,
	gpointer user_data);

	/**
	* GUnixFDSourceFunc:
	* @fd: the fd that triggered the event
	* @condition: the IO conditions reported on @fd
	* @user_data: user data passed to g_unix_fd_add()
	*
	* The type of functions to be called when a UNIX fd watch source
	* triggers.
	*
	* Returns: %FALSE if the source should be removed
	**/
	typedef gboolean (*GUnixFDSourceFunc) (gint fd,
	GIOCondition condition,
	gpointer user_data);

	GLIB_AVAILABLE_IN_2_36
	GSource *g_unix_fd_source_new (gint fd,
	GIOCondition condition);

	GLIB_AVAILABLE_IN_2_36
	guint g_unix_fd_add_full (gint priority,
	gint fd,
	GIOCondition condition,
	GUnixFDSourceFunc function,
	gpointer user_data,
	GDestroyNotify notify);

	GLIB_AVAILABLE_IN_2_36
	guint g_unix_fd_add (gint fd,
	GIOCondition condition,
	GUnixFDSourceFunc function,
	gpointer user_data);

	GLIB_AVAILABLE_IN_2_64
	struct passwd g_unix_get_passwd_entry (const gchar user_name,
	GError **error);

	/**
	* GUnixPipe:
	* @fds: A pair of file descriptors, each negative if closed or not yet opened.
	* The file descriptor with index %G_UNIX_PIPE_END_READ is readable.
	* The file descriptor with index %G_UNIX_PIPE_END_WRITE is writable.
	*
	* A Unix pipe. The advantage of this type over `int[2]` is that it can
	* be closed automatically when it goes out of scope, using `g_auto(GUnixPipe)`,
	* on compilers that support that feature.
	*
	* Since: 2.80
	*/
	GLIB_AVAILABLE_TYPE_IN_2_80
	typedef struct {
	int fds[2];
	} GUnixPipe;

	/**
	* GUnixPipeEnd:
	* @G_UNIX_PIPE_END_READ: The readable file descriptor 0
	* @G_UNIX_PIPE_END_WRITE: The writable file descriptor 1
	*
	* Mnemonic constants for the ends of a Unix pipe.
	*
	* Since: 2.80
	*/
	GLIB_AVAILABLE_TYPE_IN_2_80
	typedef enum
	{
	G_UNIX_PIPE_END_READ = 0,
	G_UNIX_PIPE_END_WRITE = 1
	} GUnixPipeEnd;

	/**
	* G_UNIX_PIPE_INIT:
	*
	* Initializer for a #GUnixPipe that has not yet been opened.
	* Both of its file descriptors are initialized to `-1` (invalid),
	* the same as if they had been closed.
	*
	* Since: 2.80
	*/
	#define G_UNIX_PIPE_INIT { { -1, -1 } } GLIB_AVAILABLE_MACRO_IN_2_80

	/* Suppress "Not available before" warnings when declaring the
	* implementations */
	G_GNUC_BEGIN_IGNORE_DEPRECATIONS

	/**
	* g_unix_pipe_open:
	* @self: A pair of file descriptors
	* @flags: Flags to pass to g_unix_open_pipe(), typically `O_CLOEXEC`
	* @error: Used to report an error on failure
	*
	* Open a pipe. This is the same as g_unix_open_pipe(), but uses the
	* #GUnixPipe data structure.
	*
	* Returns: %TRUE on success
	*
	* Since: 2.80
	*/
	GLIB_AVAILABLE_STATIC_INLINE_IN_2_80
	static inline gboolean
	g_unix_pipe_open (GUnixPipe *self,
	int flags,
	GError **error)
	{
	return g_unix_open_pipe (self->fds, flags, error);
	}

	/**
	* g_unix_pipe_get:
	* @self: A pair of file descriptors
	* @end: One of the ends of the pipe
	*
	* Return one of the ends of the pipe. It remains owned by @self.
	*
	* This function is async-signal safe (see [`signal(7)`](man:signal(7)) and
	* [`signal-safety(7)`](man:signal-safety(7))), making it safe to call from a
	* signal handler or a #GSpawnChildSetupFunc.
	*
	* This function preserves the value of `errno`.
	*
	* Returns: a non-negative file descriptor owned by @self, which must not
	* be closed by the caller, or a negative number if the corresponding
	* end of the pipe was already closed or stolen
	*
	* Since: 2.80
	*/
	GLIB_AVAILABLE_STATIC_INLINE_IN_2_80
	static inline int
	g_unix_pipe_get (GUnixPipe *self,
	GUnixPipeEnd end)
	{
	return self->fds[end];
	}

	/**
	* g_unix_pipe_steal:
	* @self: A pair of file descriptors
	* @end: One of the ends of the pipe
	*
	* Return one of the ends of the pipe. It becomes owned by the caller,
	* and the file descriptor in the data structure is set to `-1`,
	* similar to g_steal_fd().
	*
	* This function is async-signal safe (see [`signal(7)`](man:signal(7)) and
	* [`signal-safety(7)`](man:signal-safety(7))), making it safe to call from a
	* signal handler or a #GSpawnChildSetupFunc.
	*
	* This function preserves the value of `errno`.
	*
	* Returns: a non-negative file descriptor, which becomes owned by the
	* caller and must be closed by the caller if required, or a negative
	* number if the corresponding end of the pipe was already closed or stolen
	*
	* Since: 2.80
	*/
	GLIB_AVAILABLE_STATIC_INLINE_IN_2_80
	static inline int
	g_unix_pipe_steal (GUnixPipe *self,
	GUnixPipeEnd end)
	{
	return g_steal_fd (&self->fds[end]);
	}

	/**
	* g_unix_pipe_close:
	* @self: A pair of file descriptors
	* @end: One of the ends of the pipe
	* @error: Optionally used to report an error on failure
	*
	* Close one of the ends of the pipe and set the relevant member of @fds
	* to `-1` before returning, equivalent to g_clear_fd().
	*
	* Like g_close(), if closing the file descriptor fails, the error is
	* stored in both %errno and @error. If this function succeeds,
	* %errno is undefined.
	*
	* This function is async-signal safe if @error is %NULL and the relevant
	* member of @fds is either negative or a valid open file descriptor.
	* This makes it safe to call from a signal handler or a #GSpawnChildSetupFunc
	* under those conditions.
	* See [`signal(7)`](man:signal(7)) and
	* [`signal-safety(7)`](man:signal-safety(7)) for more details.
	*
	* To close both file descriptors and ignore any errors, use
	* g_unix_pipe_clear() instead.
	*
	* Returns: %TRUE on success
	*
	* Since: 2.80
	*/
	GLIB_AVAILABLE_STATIC_INLINE_IN_2_80
	static inline gboolean
	g_unix_pipe_close (GUnixPipe *self,
	GUnixPipeEnd end,
	GError **error)
	{
	return g_clear_fd (&self->fds[end], error);
	}

	/**
	* g_unix_pipe_clear:
	* @self: a #GUnixPipe
	*
	* Close both ends of the pipe, unless they have already been closed or
	* stolen. Any errors are ignored: use g_unix_pipe_close() or g_clear_fd()
	* if error-handling is required.
	*
	* This function is async-signal safe if @error is %NULL and each member
	* of @fds are either negative or a valid open file descriptor.
	* As a result, it is safe to call this function or use `g_auto(GUnixPipe)`
	* (on compilers that support it) in a signal handler or a
	* #GSpawnChildSetupFunc, as long as those conditions are ensured to be true.
	* See [`signal(7)`](man:signal(7)) and
	* [`signal-safety(7)`](man:signal-safety(7)) for more details.
	*
	* This function preserves the value of `errno`.
	*
	* Since: 2.80
	*/
	GLIB_AVAILABLE_STATIC_INLINE_IN_2_80
	static inline void
	g_unix_pipe_clear (GUnixPipe *self)
	{
	/* Don't overwrite thread-local errno if closing the fd fails */
	int errsv = errno;

	if (!g_unix_pipe_close (self, G_UNIX_PIPE_END_READ, NULL))
	{
	/* ignore */
	}

	if (!g_unix_pipe_close (self, G_UNIX_PIPE_END_WRITE, NULL))
	{
	/* ignore */
	}

	errno = errsv;
	}

	G_DEFINE_AUTO_CLEANUP_CLEAR_FUNC (GUnixPipe, g_unix_pipe_clear)

	GLIB_AVAILABLE_IN_2_80
	int g_closefrom (int lowfd);

	GLIB_AVAILABLE_IN_2_80
	int g_fdwalk_set_cloexec (int lowfd);

	G_GNUC_END_IGNORE_DEPRECATIONS

	G_END_DECLS

	#endif /* __G_UNIX_H__ */