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/* 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__ */
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