/* GLIB - Library of useful routines for C programming
* Copyright (C) 2011 Red Hat, Inc.
*
- * glib-unix.c: UNIX specific API wrappers and convenience functions
+ * 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
*
* 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
+ * 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, write to the
- * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
- * Boston, MA 02111-1307, USA.
+ * 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>
+#include <fcntl.h>
+#include <sys/syscall.h>
+#include <unistd.h>
+
+#ifdef __linux__
+
+/* We want to support these features of Linux even when building GLib
+ * against older versions of system headers. This will allow us to
+ * 'automatically' start supporting a particular feature when GLib is
+ * used with a newer kernel, without recompile.
+ *
+ * This means that we're not changing functionality of GLib simply based
+ * on the set of headers we happen to compile against...
+ */
+
+#ifndef F_LINUX_SPECIFIC_BASE
+#define F_LINUX_SPECIFIC_BASE 1024
+#endif
+
+#ifndef F_ADD_SEALS
+#define F_ADD_SEALS (F_LINUX_SPECIFIC_BASE + 9)
+#define F_GET_SEALS (F_LINUX_SPECIFIC_BASE + 10)
+
+#define F_SEAL_SEAL 0x0001 /* prevent further seals from being set */
+#define F_SEAL_SHRINK 0x0002 /* prevent file from shrinking */
+#define F_SEAL_GROW 0x0004 /* prevent file from growing */
+#define F_SEAL_WRITE 0x0008 /* prevent writes */
+#endif
+
+#endif
+
/**
* 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 constrast, this set of
- * functions is designed for programs which explicitly target UNIX, or
- * are using it to build higher level abstractions which would be
+ * 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.
*/
-GQuark
-g_unix_error_quark (void)
-{
- return g_quark_from_static_string ("g-unix-error-quark");
-}
+G_DEFINE_QUARK (g-unix-error-quark, g_unix_error)
static gboolean
-g_unix_set_error_from_errno (GError **error)
+g_unix_set_error_from_errno (GError **error,
+ gint saved_errno)
{
- int saved_errno = errno;
g_set_error_literal (error,
- G_UNIX_ERROR,
- 0,
- g_strerror (errno));
- errno = saved_errno;
- return FALSE;
-}
-
-static gboolean
-g_unix_set_error_from_errno_saved (GError **error,
- int saved_errno)
-{
- g_set_error_literal (error,
- G_UNIX_ERROR,
- 0,
- g_strerror (saved_errno));
+ G_UNIX_ERROR,
+ 0,
+ g_strerror (saved_errno));
errno = saved_errno;
return FALSE;
}
/**
- * g_unix_pipe_flags:
+ * g_unix_open_pipe:
* @fds: Array of two integers
- * @flags: Bitfield of file descriptor flags, see "man 2 fcntl"
+ * @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
+ * 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().
*
- * <note>This function does *not* take %O_CLOEXEC, it takes %FD_CLOEXEC as if
- * for fcntl(); these are different on Linux/glibc.</note>
+ * 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_pipe_flags (int *fds,
- int flags,
- GError **error)
+g_unix_open_pipe (int *fds,
+ int flags,
+ GError **error)
{
int ecode;
/* Atomic */
ecode = pipe2 (fds, pipe2_flags);
if (ecode == -1 && errno != ENOSYS)
- return g_unix_set_error_from_errno (error);
+ 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);
- ecode = fcntl (fds[0], flags);
+ 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]);
- return g_unix_set_error_from_errno_saved (error, saved_errno);
+ close (fds[1]);
+ return g_unix_set_error_from_errno (error, saved_errno);
}
- ecode = fcntl (fds[0], flags);
+ 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_saved (error, saved_errno);
+ 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. Currently only %SIGHUP, %SIGINT, and %SIGTERM can
- * be monitored. 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_create_watch().
- *
- * For example, an effective use of this function is to handle SIGTERM
+ * signal @signum. In GLib versions before 2.36, only `SIGHUP`, `SIGINT`,
+ * `SIGTERM` can be monitored. In GLib 2.36, `SIGUSR1` and `SIGUSR2`
+ * were 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
* The interaction of this source when combined with native UNIX
* functions like sigprocmask() is not defined.
*
- * <note>For reliable behavior, if your program links to gthread
- * (either directly or indirectly via GObject, GIO, or a higher level
- * library), you should ensure g_thread_init() is called before using
- * this function. For example, if your program uses GObject, call
- * g_type_init().</note>
- *
* 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, NULL);
+ g_return_val_if_fail (signum == SIGHUP || signum == SIGINT || signum == SIGTERM ||
+ signum == SIGUSR1 || signum == SIGUSR2, NULL);
return _g_main_create_unix_signal_watch (signum);
}
/**
- * g_unix_signal_add_watch_full:
- * @signum: Signal number
+ * g_unix_signal_add_full:
* @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
* using g_source_remove().
*
* Returns: An ID (greater than 0) for the event source
+ *
+ * Rename to: g_unix_signal_add
+ * Since: 2.30
*/
guint
-g_unix_signal_add_watch_full (int signum,
- int priority,
- GSourceFunc handler,
- gpointer user_data,
- GDestroyNotify notify)
+g_unix_signal_add_full (int priority,
+ int signum,
+ GSourceFunc handler,
+ gpointer user_data,
+ GDestroyNotify notify)
{
guint id;
GSource *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\n"
+ "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 #GPollFDFunc
+ * @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);
+}
+
+/**
+ * g_unix_fd_ensure_zero_copy_safe:
+ * @fd: a file descriptor
+ *
+ * Checks whether @fd can be use in zero-copy mode. On Linux, this checks that
+ * the descriptor is a memfd, created with memfd_create(), and tries to apply
+ * seals to it so that it can be safely consumed by another process. On other
+ * Unix systems, this function will fail.
+ *
+ * Returns: whether the fd is safe to use in zero-copy mode. Sealing of memfds
+ * is required for the @fd to be considered safe. If sealing fails, or
+ * memfds are not available, or the @fd is not a memfd, returns %FALSE
+ *
+ * Since: 2.44
+ **/
+gboolean
+g_unix_fd_ensure_zero_copy_safe (gint fd)
+{
+#ifdef F_GET_SEALS
+ gint seals;
+ const gint IMMUTABLE_SEALS = F_SEAL_WRITE |
+ F_SEAL_SHRINK |
+ F_SEAL_GROW |
+ F_SEAL_SEAL;
+
+ g_return_val_if_fail (fd >= 0, FALSE);
+
+ /* Seal the fd if possible (only on Linux 3.17+, and if the fd was created
+ * with memfd_create()). */
+ seals = fcntl (fd, F_GET_SEALS);
+ if (seals == -1)
+ {
+ g_debug ("Retrieving fd seals failed: %s", g_strerror (errno));
+ return FALSE;
+ }
+
+ /* Seal the fd, if it is not already. */
+ if ((seals & (IMMUTABLE_SEALS)) >= IMMUTABLE_SEALS)
+ {
+ g_debug ("%s", "fd already sealed");
+ }
+ else
+ {
+ gint error;
+
+ error = fcntl (fd, F_ADD_SEALS, IMMUTABLE_SEALS);
+ if (error == -1)
+ {
+ g_debug ("fd sealing failed: %s", g_strerror (errno));
+ return FALSE;
+ }
+ }
+
+ return TRUE;
+#else
+ return FALSE;
+#endif
+}
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