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/* GLIB - Library of useful routines for C programming
* Copyright (C) 2011 Red Hat, Inc.
*
* glib-unix.c: UNIX specific API wrappers and convenience functions
*
* 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/>.
*
* Authors: Colin Walters <walters@verbum.org>
*/
#include "config.h"
/* To make bionic export pipe2() */
#ifndef _GNU_SOURCE
#define _GNU_SOURCE 1
#endif
#include "glib-unix.h"
#include "gmain-internal.h"
#include <string.h>
/**
* SECTION:gunix
* @title: UNIX-specific utilities and integration
* @short_description: pipes, signal handling
* @include: glib-unix.h
*
* Most of GLib is intended to be portable; in contrast, this set of
* functions is designed for programs which explicitly target UNIX,
* or are using it to build higher level abstractions which would be
* conditionally compiled if the platform matches G_OS_UNIX.
*
* To use these functions, you must explicitly include the
* "glib-unix.h" header.
*/
G_DEFINE_QUARK (g-unix-error-quark, g_unix_error)
static gboolean
g_unix_set_error_from_errno (GError **error,
gint saved_errno)
{
g_set_error_literal (error,
G_UNIX_ERROR,
0,
g_strerror (saved_errno));
errno = saved_errno;
return FALSE;
}
/**
* g_unix_open_pipe:
* @fds: Array of two integers
* @flags: Bitfield of file descriptor flags, as for fcntl()
* @error: a #GError
*
* Similar to the UNIX pipe() call, but on modern systems like Linux
* uses the pipe2() system call, which atomically creates a pipe with
* the configured flags. The only supported flag currently is
* %FD_CLOEXEC. If for example you want to configure %O_NONBLOCK, that
* must still be done separately with fcntl().
*
* This function does not take %O_CLOEXEC, it takes %FD_CLOEXEC as if
* for fcntl(); these are different on Linux/glibc.
*
* Returns: %TRUE on success, %FALSE if not (and errno will be set).
*
* Since: 2.30
*/
gboolean
g_unix_open_pipe (int *fds,
int flags,
GError **error)
{
int ecode;
/* We only support FD_CLOEXEC */
g_return_val_if_fail ((flags & (FD_CLOEXEC)) == flags, FALSE);
#ifdef HAVE_PIPE2
{
int pipe2_flags = 0;
if (flags & FD_CLOEXEC)
pipe2_flags |= O_CLOEXEC;
/* Atomic */
ecode = pipe2 (fds, pipe2_flags);
if (ecode == -1 && errno != ENOSYS)
return g_unix_set_error_from_errno (error, errno);
else if (ecode == 0)
return TRUE;
/* Fall through on -ENOSYS, we must be running on an old kernel */
}
#endif
ecode = pipe (fds);
if (ecode == -1)
return g_unix_set_error_from_errno (error, errno);
if (flags == 0)
return TRUE;
ecode = fcntl (fds[0], F_SETFD, flags);
if (ecode == -1)
{
int saved_errno = errno;
close (fds[0]);
close (fds[1]);
return g_unix_set_error_from_errno (error, saved_errno);
}
ecode = fcntl (fds[1], F_SETFD, flags);
if (ecode == -1)
{
int saved_errno = errno;
close (fds[0]);
close (fds[1]);
return g_unix_set_error_from_errno (error, saved_errno);
}
return TRUE;
}
/**
* g_unix_set_fd_nonblocking:
* @fd: A file descriptor
* @nonblock: If %TRUE, set the descriptor to be non-blocking
* @error: a #GError
*
* Control the non-blocking state of the given file descriptor,
* according to @nonblock. On most systems this uses %O_NONBLOCK, but
* on some older ones may use %O_NDELAY.
*
* Returns: %TRUE if successful
*
* Since: 2.30
*/
gboolean
g_unix_set_fd_nonblocking (gint fd,
gboolean nonblock,
GError **error)
{
#ifdef F_GETFL
glong fcntl_flags;
fcntl_flags = fcntl (fd, F_GETFL);
if (fcntl_flags == -1)
return g_unix_set_error_from_errno (error, errno);
if (nonblock)
{
#ifdef O_NONBLOCK
fcntl_flags |= O_NONBLOCK;
#else
fcntl_flags |= O_NDELAY;
#endif
}
else
{
#ifdef O_NONBLOCK
fcntl_flags &= ~O_NONBLOCK;
#else
fcntl_flags &= ~O_NDELAY;
#endif
}
if (fcntl (fd, F_SETFL, fcntl_flags) == -1)
return g_unix_set_error_from_errno (error, errno);
return TRUE;
#else
return g_unix_set_error_from_errno (error, EINVAL);
#endif
}
/**
* g_unix_signal_source_new:
* @signum: A signal number
*
* Create a #GSource that will be dispatched upon delivery of the UNIX
* signal @signum. In GLib versions before 2.36, only `SIGHUP`, `SIGINT`,
* `SIGTERM` can be monitored. In GLib 2.36, `SIGUSR1` and `SIGUSR2`
* were added. In GLib 2.54, `SIGWINCH` was added.
*
* Note that unlike the UNIX default, all sources which have created a
* watch will be dispatched, regardless of which underlying thread
* invoked g_unix_signal_source_new().
*
* For example, an effective use of this function is to handle `SIGTERM`
* cleanly; flushing any outstanding files, and then calling
* g_main_loop_quit (). It is not safe to do any of this a regular
* UNIX signal handler; your handler may be invoked while malloc() or
* another library function is running, causing reentrancy if you
* attempt to use it from the handler. None of the GLib/GObject API
* is safe against this kind of reentrancy.
*
* The interaction of this source when combined with native UNIX
* functions like sigprocmask() is not defined.
*
* The source will not initially be associated with any #GMainContext
* and must be added to one with g_source_attach() before it will be
* executed.
*
* Returns: A newly created #GSource
*
* Since: 2.30
*/
GSource *
g_unix_signal_source_new (int signum)
{
g_return_val_if_fail (signum == SIGHUP || signum == SIGINT || signum == SIGTERM ||
signum == SIGUSR1 || signum == SIGUSR2 || signum == SIGWINCH,
NULL);
return _g_main_create_unix_signal_watch (signum);
}
/**
* g_unix_signal_add_full: (rename-to g_unix_signal_add)
* @priority: the priority of the signal source. Typically this will be in
* the range between #G_PRIORITY_DEFAULT and #G_PRIORITY_HIGH.
* @signum: Signal number
* @handler: Callback
* @user_data: Data for @handler
* @notify: #GDestroyNotify for @handler
*
* A convenience function for g_unix_signal_source_new(), which
* attaches to the default #GMainContext. You can remove the watch
* using g_source_remove().
*
* Returns: An ID (greater than 0) for the event source
*
* Since: 2.30
*/
guint
g_unix_signal_add_full (int priority,
int signum,
GSourceFunc handler,
gpointer user_data,
GDestroyNotify notify)
{
guint id;
GSource *source;
source = g_unix_signal_source_new (signum);
if (priority != G_PRIORITY_DEFAULT)
g_source_set_priority (source, priority);
g_source_set_callback (source, handler, user_data, notify);
id = g_source_attach (source, NULL);
g_source_unref (source);
return id;
}
/**
* g_unix_signal_add:
* @signum: Signal number
* @handler: Callback
* @user_data: Data for @handler
*
* A convenience function for g_unix_signal_source_new(), which
* attaches to the default #GMainContext. You can remove the watch
* using g_source_remove().
*
* Returns: An ID (greater than 0) for the event source
*
* Since: 2.30
*/
guint
g_unix_signal_add (int signum,
GSourceFunc handler,
gpointer user_data)
{
return g_unix_signal_add_full (G_PRIORITY_DEFAULT, signum, handler, user_data, NULL);
}
typedef struct
{
GSource source;
gint fd;
gpointer tag;
} GUnixFDSource;
static gboolean
g_unix_fd_source_dispatch (GSource *source,
GSourceFunc callback,
gpointer user_data)
{
GUnixFDSource *fd_source = (GUnixFDSource *) source;
GUnixFDSourceFunc func = (GUnixFDSourceFunc) callback;
if (!callback)
{
g_warning ("GUnixFDSource dispatched without callback. "
"You must call g_source_set_callback().");
return FALSE;
}
return (* func) (fd_source->fd, g_source_query_unix_fd (source, fd_source->tag), user_data);
}
GSourceFuncs g_unix_fd_source_funcs = {
NULL, NULL, g_unix_fd_source_dispatch, NULL
};
/**
* g_unix_fd_source_new:
* @fd: a file descriptor
* @condition: IO conditions to watch for on @fd
*
* Creates a #GSource to watch for a particular IO condition on a file
* descriptor.
*
* The source will never close the fd -- you must do it yourself.
*
* Returns: the newly created #GSource
*
* Since: 2.36
**/
GSource *
g_unix_fd_source_new (gint fd,
GIOCondition condition)
{
GUnixFDSource *fd_source;
GSource *source;
source = g_source_new (&g_unix_fd_source_funcs, sizeof (GUnixFDSource));
fd_source = (GUnixFDSource *) source;
fd_source->fd = fd;
fd_source->tag = g_source_add_unix_fd (source, fd, condition);
return source;
}
/**
* g_unix_fd_add_full:
* @priority: the priority of the source
* @fd: a file descriptor
* @condition: IO conditions to watch for on @fd
* @function: a #GUnixFDSourceFunc
* @user_data: data to pass to @function
* @notify: function to call when the idle is removed, or %NULL
*
* Sets a function to be called when the IO condition, as specified by
* @condition becomes true for @fd.
*
* This is the same as g_unix_fd_add(), except that it allows you to
* specify a non-default priority and a provide a #GDestroyNotify for
* @user_data.
*
* Returns: the ID (greater than 0) of the event source
*
* Since: 2.36
**/
guint
g_unix_fd_add_full (gint priority,
gint fd,
GIOCondition condition,
GUnixFDSourceFunc function,
gpointer user_data,
GDestroyNotify notify)
{
GSource *source;
guint id;
g_return_val_if_fail (function != NULL, 0);
source = g_unix_fd_source_new (fd, condition);
if (priority != G_PRIORITY_DEFAULT)
g_source_set_priority (source, priority);
g_source_set_callback (source, (GSourceFunc) function, user_data, notify);
id = g_source_attach (source, NULL);
g_source_unref (source);
return id;
}
/**
* g_unix_fd_add:
* @fd: a file descriptor
* @condition: IO conditions to watch for on @fd
* @function: a #GUnixFDSourceFunc
* @user_data: data to pass to @function
*
* Sets a function to be called when the IO condition, as specified by
* @condition becomes true for @fd.
*
* @function will be called when the specified IO condition becomes
* %TRUE. The function is expected to clear whatever event caused the
* IO condition to become true and return %TRUE in order to be notified
* when it happens again. If @function returns %FALSE then the watch
* will be cancelled.
*
* The return value of this function can be passed to g_source_remove()
* to cancel the watch at any time that it exists.
*
* The source will never close the fd -- you must do it yourself.
*
* Returns: the ID (greater than 0) of the event source
*
* Since: 2.36
**/
guint
g_unix_fd_add (gint fd,
GIOCondition condition,
GUnixFDSourceFunc function,
gpointer user_data)
{
return g_unix_fd_add_full (G_PRIORITY_DEFAULT, fd, condition, function, user_data, NULL);
}