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);
108 ecode = fcntl (fds[0], flags);
111 int saved_errno = errno;
114 return g_unix_set_error_from_errno (error, saved_errno);
116 ecode = fcntl (fds[1], flags);
119 int saved_errno = errno;
122 return g_unix_set_error_from_errno (error, saved_errno);
128 * g_unix_set_fd_nonblocking:
129 * @fd: A file descriptor
130 * @nonblock: If %TRUE, set the descriptor to be non-blocking
133 * Control the non-blocking state of the given file descriptor,
134 * according to @nonblock. On most systems this uses <literal>O_NONBLOCK</literal>, but
135 * on some older ones may use <literal>O_NDELAY</literal>.
137 * Returns: %TRUE if successful
142 g_unix_set_fd_nonblocking (gint fd,
148 fcntl_flags = fcntl (fd, F_GETFL);
150 if (fcntl_flags == -1)
151 return g_unix_set_error_from_errno (error, errno);
156 fcntl_flags |= O_NONBLOCK;
158 fcntl_flags |= O_NDELAY;
164 fcntl_flags &= ~O_NONBLOCK;
166 fcntl_flags &= ~O_NDELAY;
170 if (fcntl (fd, F_SETFL, fcntl_flags) == -1)
171 return g_unix_set_error_from_errno (error, errno);
174 return g_unix_set_error_from_errno (error, EINVAL);
180 * g_unix_signal_source_new:
181 * @signum: A signal number
183 * Create a #GSource that will be dispatched upon delivery of the UNIX
184 * signal @signum. In GLib versions before 2.36, only
185 * <literal>SIGHUP</literal>, <literal>SIGINT</literal>,
186 * <literal>SIGTERM</literal> can be monitored. In GLib 2.36,
187 * <literal>SIGUSR1</literal> and <literal>SIGUSR2</literal> were
190 * Note that unlike the UNIX default, all sources which have created a
191 * watch will be dispatched, regardless of which underlying thread
192 * invoked g_unix_signal_source_new().
194 * For example, an effective use of this function is to handle <literal>SIGTERM</literal>
195 * cleanly; flushing any outstanding files, and then calling
196 * g_main_loop_quit (). It is not safe to do any of this a regular
197 * UNIX signal handler; your handler may be invoked while malloc() or
198 * another library function is running, causing reentrancy if you
199 * attempt to use it from the handler. None of the GLib/GObject API
200 * is safe against this kind of reentrancy.
202 * The interaction of this source when combined with native UNIX
203 * functions like sigprocmask() is not defined.
205 * The source will not initially be associated with any #GMainContext
206 * and must be added to one with g_source_attach() before it will be
209 * Returns: A newly created #GSource
214 g_unix_signal_source_new (int signum)
216 g_return_val_if_fail (signum == SIGHUP || signum == SIGINT || signum == SIGTERM ||
217 signum == SIGUSR1 || signum == SIGUSR2, NULL);
219 return _g_main_create_unix_signal_watch (signum);
223 * g_unix_signal_add_full:
224 * @priority: the priority of the signal source. Typically this will be in
225 * the range between #G_PRIORITY_DEFAULT and #G_PRIORITY_HIGH.
226 * @signum: Signal number
228 * @user_data: Data for @handler
229 * @notify: #GDestroyNotify for @handler
231 * A convenience function for g_unix_signal_source_new(), which
232 * attaches to the default #GMainContext. You can remove the watch
233 * using g_source_remove().
235 * Returns: An ID (greater than 0) for the event source
240 g_unix_signal_add_full (int priority,
244 GDestroyNotify notify)
249 source = g_unix_signal_source_new (signum);
251 if (priority != G_PRIORITY_DEFAULT)
252 g_source_set_priority (source, priority);
254 g_source_set_callback (source, handler, user_data, notify);
255 id = g_source_attach (source, NULL);
256 g_source_unref (source);
263 * @signum: Signal number
265 * @user_data: Data for @handler
267 * A convenience function for g_unix_signal_source_new(), which
268 * attaches to the default #GMainContext. You can remove the watch
269 * using g_source_remove().
271 * Returns: An ID (greater than 0) for the event source
276 g_unix_signal_add (int signum,
280 return g_unix_signal_add_full (G_PRIORITY_DEFAULT, signum, handler, user_data, NULL);