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/* GLIB - Library of useful routines for C programming
*
* gthreadprivate.h - GLib internal thread system related declarations.
*
* Copyright (C) 2003 Sebastian Wilhelmi
*
* 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_THREADPRIVATE_H__
#define __G_THREADPRIVATE_H__
#include "config.h"
#include "deprecated/gthread.h"
typedef struct _GRealThread GRealThread;
struct _GRealThread
{
GThread thread;
gint ref_count;
gboolean ours;
char name[16];
gpointer retval;
};
/* system thread implementation (gthread-posix.c, gthread-win32.c) */
#if defined(HAVE_FUTEX) || defined(HAVE_FUTEX_TIME64)
#include <errno.h>
#include <linux/futex.h>
#include <sys/syscall.h>
#include <unistd.h>
#ifndef FUTEX_WAIT_PRIVATE
#define FUTEX_WAIT_PRIVATE FUTEX_WAIT
#define FUTEX_WAKE_PRIVATE FUTEX_WAKE
#endif
/* Wrapper macro to call `futex_time64` and/or `futex` with simple
* parameters and without returning the return value.
*
* We expect futex to sometimes return EAGAIN due to the race
* between the caller checking the current value and deciding to
* do the futex op. To avoid splattering errno on success, we
* restore the original errno if EAGAIN is seen. See also:
* https://gitlab.gnome.org/GNOME/glib/-/issues/3034
*
* If the `futex_time64` syscall does not exist (`ENOSYS`), we retry again
* with the normal `futex` syscall. This can happen if newer kernel headers
* are used than the kernel that is actually running.
*
* The `futex_time64` syscall is also skipped in favour of `futex` if the
* Android runtime’s API level is lower than 30, as it’s blocked by seccomp
* there and using it will cause the app to be terminated:
* https://android-review.googlesource.com/c/platform/bionic/+/1094758
* https://github.com/aosp-mirror/platform_bionic/commit/ee7bc3002dc3127faac110167d28912eb0e86a20
*
* This must not be called with a timeout parameter as that differs
* in size between the two syscall variants!
*/
#if defined(HAVE_FUTEX) && defined(HAVE_FUTEX_TIME64)
#if defined(__ANDROID__)
#define g_futex_simple(uaddr, futex_op, ...) \
G_STMT_START \
{ \
int saved_errno = errno; \
int res = 0; \
if (__builtin_available (android 30, *)) \
{ \
res = syscall (__NR_futex_time64, uaddr, (gsize) futex_op, __VA_ARGS__); \
if (res < 0 && errno == ENOSYS) \
{ \
errno = saved_errno; \
res = syscall (__NR_futex, uaddr, (gsize) futex_op, __VA_ARGS__); \
} \
} \
else \
{ \
res = syscall (__NR_futex, uaddr, (gsize) futex_op, __VA_ARGS__); \
} \
if (res < 0 && errno == EAGAIN) \
{ \
errno = saved_errno; \
} \
} \
G_STMT_END
#else
#define g_futex_simple(uaddr, futex_op, ...) \
G_STMT_START \
{ \
int saved_errno = errno; \
int res = syscall (__NR_futex_time64, uaddr, (gsize) futex_op, __VA_ARGS__); \
if (res < 0 && errno == ENOSYS) \
{ \
errno = saved_errno; \
res = syscall (__NR_futex, uaddr, (gsize) futex_op, __VA_ARGS__); \
} \
if (res < 0 && errno == EAGAIN) \
{ \
errno = saved_errno; \
} \
} \
G_STMT_END
#endif /* defined(__ANDROID__) */
#elif defined(HAVE_FUTEX_TIME64)
#define g_futex_simple(uaddr, futex_op, ...) \
G_STMT_START \
{ \
int saved_errno = errno; \
int res = syscall (__NR_futex_time64, uaddr, (gsize) futex_op, __VA_ARGS__); \
if (res < 0 && errno == EAGAIN) \
{ \
errno = saved_errno; \
} \
} \
G_STMT_END
#elif defined(HAVE_FUTEX)
#define g_futex_simple(uaddr, futex_op, ...) \
G_STMT_START \
{ \
int saved_errno = errno; \
int res = syscall (__NR_futex, uaddr, (gsize) futex_op, __VA_ARGS__); \
if (res < 0 && errno == EAGAIN) \
{ \
errno = saved_errno; \
} \
} \
G_STMT_END
#else /* !defined(HAVE_FUTEX) && !defined(HAVE_FUTEX_TIME64) */
#error "Neither __NR_futex nor __NR_futex_time64 are available"
#endif /* defined(HAVE_FUTEX) && defined(HAVE_FUTEX_TIME64) */
#endif
void g_system_thread_wait (GRealThread *thread);
GRealThread *g_system_thread_new (GThreadFunc proxy,
gulong stack_size,
const char *name,
GThreadFunc func,
gpointer data,
GError **error);
void g_system_thread_free (GRealThread *thread);
G_NORETURN void g_system_thread_exit (void);
void g_system_thread_set_name (const gchar *name);
void g_system_thread_get_name (char *buffer,
gsize length);
/* gthread.c */
GThread *g_thread_new_internal (const gchar *name,
GThreadFunc proxy,
GThreadFunc func,
gpointer data,
gsize stack_size,
GError **error);
gpointer g_thread_proxy (gpointer thread);
guint g_thread_n_created (void);
gpointer g_private_set_alloc0 (GPrivate *key,
gsize size);
#endif /* __G_THREADPRIVATE_H__ */
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