1 /* GLIB - Library of useful routines for C programming
2 * Copyright (C) 2011 Red Hat, Inc.
4 * glib-unix.c: UNIX specific API wrappers and convenience functions
6 * This library is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
9 * version 2 of the License, or (at your option) any later version.
11 * This library is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * Lesser General Public License for more details.
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with this library; if not, write to the
18 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
19 * Boston, MA 02111-1307, USA.
21 * Authors: Colin Walters <walters@verbum.org>
26 #include "glib-unix.h"
27 #include "gmain-internal.h"
33 * @title: UNIX-specific utilities and integration
34 * @short_description: pipes, signal handling
35 * @include: glib-unix.h
37 * Most of GLib is intended to be portable; in contrast, this set of
38 * functions is designed for programs which explicitly target UNIX,
39 * or are using it to build higher level abstractions which would be
40 * conditionally compiled if the platform matches G_OS_UNIX.
42 * To use these functions, you must explicitly include the
43 * "glib-unix.h" header.
46 G_DEFINE_QUARK (g
-unix
-error
-quark
, g_unix_error
)
49 g_unix_set_error_from_errno (GError
**error
,
52 g_set_error_literal (error
,
55 g_strerror (saved_errno
));
62 * @fds: Array of two integers
63 * @flags: Bitfield of file descriptor flags, see "man 2 fcntl"
66 * Similar to the UNIX pipe() call, but on modern systems like Linux
67 * uses the pipe2() system call, which atomically creates a pipe with
68 * the configured flags. The only supported flag currently is
69 * <literal>FD_CLOEXEC</literal>. If for example you want to configure
70 * <literal>O_NONBLOCK</literal>, that must still be done separately with
73 * <note>This function does *not* take <literal>O_CLOEXEC</literal>, it takes
74 * <literal>FD_CLOEXEC</literal> as if for fcntl(); these are
75 * different on Linux/glibc.</note>
77 * Returns: %TRUE on success, %FALSE if not (and errno will be set).
82 g_unix_open_pipe (int *fds
,
88 /* We only support FD_CLOEXEC */
89 g_return_val_if_fail ((flags
& (FD_CLOEXEC
)) == flags
, FALSE
);
94 if (flags
& FD_CLOEXEC
)
95 pipe2_flags
|= O_CLOEXEC
;
97 ecode
= pipe2 (fds
, pipe2_flags
);
98 if (ecode
== -1 && errno
!= ENOSYS
)
99 return g_unix_set_error_from_errno (error
, errno
);
102 /* Fall through on -ENOSYS, we must be running on an old kernel */
107 return g_unix_set_error_from_errno (error
, errno
);
112 ecode
= fcntl (fds
[0], F_SETFD
, flags
);
115 int saved_errno
= errno
;
118 return g_unix_set_error_from_errno (error
, saved_errno
);
120 ecode
= fcntl (fds
[1], F_SETFD
, flags
);
123 int saved_errno
= errno
;
126 return g_unix_set_error_from_errno (error
, saved_errno
);
132 * g_unix_set_fd_nonblocking:
133 * @fd: A file descriptor
134 * @nonblock: If %TRUE, set the descriptor to be non-blocking
137 * Control the non-blocking state of the given file descriptor,
138 * according to @nonblock. On most systems this uses <literal>O_NONBLOCK</literal>, but
139 * on some older ones may use <literal>O_NDELAY</literal>.
141 * Returns: %TRUE if successful
146 g_unix_set_fd_nonblocking (gint fd
,
152 fcntl_flags
= fcntl (fd
, F_GETFL
);
154 if (fcntl_flags
== -1)
155 return g_unix_set_error_from_errno (error
, errno
);
160 fcntl_flags
|= O_NONBLOCK
;
162 fcntl_flags
|= O_NDELAY
;
168 fcntl_flags
&= ~O_NONBLOCK
;
170 fcntl_flags
&= ~O_NDELAY
;
174 if (fcntl (fd
, F_SETFL
, fcntl_flags
) == -1)
175 return g_unix_set_error_from_errno (error
, errno
);
178 return g_unix_set_error_from_errno (error
, EINVAL
);
183 * g_unix_signal_source_new:
184 * @signum: A signal number
186 * Create a #GSource that will be dispatched upon delivery of the UNIX
187 * signal @signum. In GLib versions before 2.36, only
188 * <literal>SIGHUP</literal>, <literal>SIGINT</literal>,
189 * <literal>SIGTERM</literal> can be monitored. In GLib 2.36,
190 * <literal>SIGUSR1</literal> and <literal>SIGUSR2</literal> were
193 * Note that unlike the UNIX default, all sources which have created a
194 * watch will be dispatched, regardless of which underlying thread
195 * invoked g_unix_signal_source_new().
197 * For example, an effective use of this function is to handle <literal>SIGTERM</literal>
198 * cleanly; flushing any outstanding files, and then calling
199 * g_main_loop_quit (). It is not safe to do any of this a regular
200 * UNIX signal handler; your handler may be invoked while malloc() or
201 * another library function is running, causing reentrancy if you
202 * attempt to use it from the handler. None of the GLib/GObject API
203 * is safe against this kind of reentrancy.
205 * The interaction of this source when combined with native UNIX
206 * functions like sigprocmask() is not defined.
208 * The source will not initially be associated with any #GMainContext
209 * and must be added to one with g_source_attach() before it will be
212 * Returns: A newly created #GSource
217 g_unix_signal_source_new (int signum
)
219 g_return_val_if_fail (signum
== SIGHUP
|| signum
== SIGINT
|| signum
== SIGTERM
||
220 signum
== SIGUSR1
|| signum
== SIGUSR2
, NULL
);
222 return _g_main_create_unix_signal_watch (signum
);
226 * g_unix_signal_add_full:
227 * @priority: the priority of the signal source. Typically this will be in
228 * the range between #G_PRIORITY_DEFAULT and #G_PRIORITY_HIGH.
229 * @signum: Signal number
231 * @user_data: Data for @handler
232 * @notify: #GDestroyNotify for @handler
234 * A convenience function for g_unix_signal_source_new(), which
235 * attaches to the default #GMainContext. You can remove the watch
236 * using g_source_remove().
238 * Returns: An ID (greater than 0) for the event source
240 * Rename to: g_unix_signal_add
244 g_unix_signal_add_full (int priority
,
248 GDestroyNotify notify
)
253 source
= g_unix_signal_source_new (signum
);
255 if (priority
!= G_PRIORITY_DEFAULT
)
256 g_source_set_priority (source
, priority
);
258 g_source_set_callback (source
, handler
, user_data
, notify
);
259 id
= g_source_attach (source
, NULL
);
260 g_source_unref (source
);
267 * @signum: Signal number
269 * @user_data: Data for @handler
271 * A convenience function for g_unix_signal_source_new(), which
272 * attaches to the default #GMainContext. You can remove the watch
273 * using g_source_remove().
275 * Returns: An ID (greater than 0) for the event source
280 g_unix_signal_add (int signum
,
284 return g_unix_signal_add_full (G_PRIORITY_DEFAULT
, signum
, handler
, user_data
, NULL
);
296 g_unix_fd_source_dispatch (GSource
*source
,
297 GSourceFunc callback
,
300 GUnixFDSource
*fd_source
= (GUnixFDSource
*) source
;
301 GUnixFDSourceFunc func
= (GUnixFDSourceFunc
) callback
;
305 g_warning ("GUnixFDSource dispatched without callback\n"
306 "You must call g_source_set_callback().");
310 return (* func
) (fd_source
->fd
, g_source_query_unix_fd (source
, fd_source
->tag
), user_data
);
315 * g_unix_fd_source_new:
316 * @fd: a file descriptor
317 * @condition: IO conditions to watch for on @fd
319 * Creates a #GSource to watch for a particular IO condition on a file
322 * The source will never close the fd -- you must do it yourself.
324 * Returns: the newly created #GSource
329 g_unix_fd_source_new (gint fd
,
330 GIOCondition condition
)
332 static GSourceFuncs source_funcs
= {
333 NULL
, NULL
, g_unix_fd_source_dispatch
, NULL
335 GUnixFDSource
*fd_source
;
338 source
= g_source_new (&source_funcs
, sizeof (GUnixFDSource
));
339 fd_source
= (GUnixFDSource
*) source
;
342 fd_source
->tag
= g_source_add_unix_fd (source
, fd
, condition
);
348 * g_unix_fd_add_full:
349 * @priority: the priority of the source
350 * @fd: a file descriptor
351 * @condition: IO conditions to watch for on @fd
352 * @function: a #GUnixFDSourceFunc
353 * @user_data: data to pass to @function
354 * @notify: function to call when the idle is removed, or %NULL
356 * Sets a function to be called when the IO condition, as specified by
357 * @condition becomes true for @fd.
359 * This is the same as g_unix_fd_add(), except that it allows you to
360 * specify a non-default priority and a provide a #GDestroyNotify for
363 * Returns: the ID (greater than 0) of the event source
368 g_unix_fd_add_full (gint priority
,
370 GIOCondition condition
,
371 GUnixFDSourceFunc function
,
373 GDestroyNotify notify
)
378 g_return_val_if_fail (function
!= NULL
, 0);
380 source
= g_unix_fd_source_new (fd
, condition
);
382 if (priority
!= G_PRIORITY_DEFAULT
)
383 g_source_set_priority (source
, priority
);
385 g_source_set_callback (source
, (GSourceFunc
) function
, user_data
, notify
);
386 id
= g_source_attach (source
, NULL
);
387 g_source_unref (source
);
394 * @fd: a file descriptor
395 * @condition: IO conditions to watch for on @fd
396 * @function: a #GPollFDFunc
397 * @user_data: data to pass to @function
399 * Sets a function to be called when the IO condition, as specified by
400 * @condition becomes true for @fd.
402 * @function will be called when the specified IO condition becomes
403 * %TRUE. The function is expected to clear whatever event caused the
404 * IO condition to become true and return %TRUE in order to be notified
405 * when it happens again. If @function returns %FALSE then the watch
408 * The return value of this function can be passed to g_source_remove()
409 * to cancel the watch at any time that it exists.
411 * The source will never close the fd -- you must do it yourself.
413 * Returns: the ID (greater than 0) of the event source
418 g_unix_fd_add (gint fd
,
419 GIOCondition condition
,
420 GUnixFDSourceFunc function
,
423 return g_unix_fd_add_full (G_PRIORITY_DEFAULT
, fd
, condition
, function
, user_data
, NULL
);