gstreamer1.0: use futex_time64 syscall if available (32-bit systems) #1725

recipes-multimedia/gstreamer/gstreamer1.0/0006-systemclock-Use-futex_time64-syscall-if-available-32.patch

@@ -0,0 +1,211 @@
+From 9ca6b1196e31a4a483fdddad191221616e2c9c3d Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Sebastian=20Dr=C3=B6ge?= <[email protected]>
+Date: Mon, 12 Dec 2022 11:34:51 +0200
+Subject: [PATCH] systemclock: Use `futex_time64` syscall if available (32-bit
+ systems) and use correct `struct timespec` definition
+
+See also https://gitlab.gnome.org/GNOME/glib/-/issues/2634
+
+Fixes https://gitlab.freedesktop.org/gstreamer/gstreamer/-/issues/1648
+
+Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/3561>
+---
+ gst/gstsystemclock.c | 125 ++++++++++++++++++---
+ meson.build          |  11 +-
+ 2 files changed, 121 insertions(+), 15 deletions(-)
+
+diff --git a/gst/gstsystemclock.c b/gst/gstsystemclock.c
+index 6d0b6ec47b..7d8efb171e 100644
+--- a/gst/gstsystemclock.c
++++ b/gst/gstsystemclock.c
+@@ -70,11 +70,15 @@
+ #define GST_SYSTEM_CLOCK_WAIT(clock)            g_cond_wait(GST_SYSTEM_CLOCK_GET_COND(clock),GST_SYSTEM_CLOCK_GET_LOCK(clock))
+ #define GST_SYSTEM_CLOCK_BROADCAST(clock)       g_cond_broadcast(GST_SYSTEM_CLOCK_GET_COND(clock))
+
+-#if defined(HAVE_FUTEX)
++#if defined(HAVE_FUTEX) || defined(HAVE_FUTEX_TIME64)
+ #include <unistd.h>
+ #include <linux/futex.h>
+ #include <sys/syscall.h>
+
++#if !defined(__NR_futex) && !defined(__NR_futex_time64)
++#error "Neither __NR_futex nor __NR_futex_time64 are defined but were found by meson"
++#endif
++
+ #ifndef FUTEX_WAIT_BITSET_PRIVATE
+ #define FUTEX_WAIT_BITSET_PRIVATE FUTEX_WAIT_BITSET
+ #endif
+@@ -123,14 +127,35 @@ gst_futex_cond_broadcast (guint * cond_val)
+ {
+   g_atomic_int_inc (cond_val);
+
++#if defined(__NR_futex_time64)
++  {
++    int res;
++    res = syscall (__NR_futex_time64, cond_val, (gsize) FUTEX_WAKE_PRIVATE,
++        (gsize) INT_MAX, NULL);
++
++    /* If the syscall does not exist (`ENOSYS`), we retry again below with the
++     * normal `futex` syscall. This can happen if newer kernel headers are
++     * used than the kernel that is actually running.
++     */
++#ifdef __NR_futex
++    if (res >= 0 || errno != ENOSYS) {
++#else
++    {
++#endif
++      return;
++    }
++  }
++#endif
++
++#if defined(__NR_futex)
+   syscall (__NR_futex, cond_val, (gsize) FUTEX_WAKE_PRIVATE, (gsize) INT_MAX,
+       NULL);
++#endif
+ }
+
+ static gboolean
+ gst_futex_cond_wait_until (guint * cond_val, GMutex * mutex, gint64 end_time)
+ {
+-  struct timespec end;
+   guint sampled;
+   int res;
+   gboolean success;
+@@ -138,20 +163,92 @@ gst_futex_cond_wait_until (guint * cond_val, GMutex * mutex, gint64 end_time)
+   if (end_time < 0)
+     return FALSE;
+
+-  end.tv_sec = end_time / 1000000000;
+-  end.tv_nsec = end_time % 1000000000;
+-
+   sampled = *cond_val;
+   g_mutex_unlock (mutex);
+-  /* we use FUTEX_WAIT_BITSET_PRIVATE rather than FUTEX_WAIT_PRIVATE to be
+-   * able to use absolute time */
+-  res =
+-      syscall (__NR_futex, cond_val, (gsize) FUTEX_WAIT_BITSET_PRIVATE,
+-      (gsize) sampled, &end, NULL, FUTEX_BITSET_MATCH_ANY);
+-  success = (res < 0 && errno == ETIMEDOUT) ? FALSE : TRUE;
+-  g_mutex_lock (mutex);
+-
+-  return success;
++
++  /* `struct timespec` as defined by the libc headers does not necessarily
++   * have any relation to the one used by the kernel for the `futex` syscall.
++   *
++   * Specifically, the libc headers might use 64-bit `time_t` while the kernel
++   * headers use 32-bit `__kernel_old_time_t` on certain systems.
++   *
++   * To get around this problem we
++   *   a) check if `futex_time64` is available, which only exists on 32-bit
++   *      platforms and always uses 64-bit `time_t`.
++   *   b) otherwise (or if that returns `ENOSYS`), we call the normal `futex`
++   *      syscall with the `struct timespec_t` used by the kernel, which uses
++   *      `__kernel_long_t` for both its fields. We use that instead of
++   *      `__kernel_old_time_t` because it is equivalent and available in the
++   *      kernel headers for a longer time.
++   *
++   * Also some 32-bit systems do not define `__NR_futex` at all and only
++   * define `__NR_futex_time64`.
++   */
++
++#ifdef __NR_futex_time64
++  {
++    struct
++    {
++      gint64 tv_sec;
++      gint64 tv_nsec;
++    } end;
++
++    end.tv_sec = end_time / 1000000000;
++    end.tv_nsec = end_time % 1000000000;
++
++    /* we use FUTEX_WAIT_BITSET_PRIVATE rather than FUTEX_WAIT_PRIVATE to be
++     * able to use absolute time */
++    res =
++        syscall (__NR_futex_time64, cond_val, (gsize) FUTEX_WAIT_BITSET_PRIVATE,
++        (gsize) sampled, &end, NULL, FUTEX_BITSET_MATCH_ANY);
++
++    /* If the syscall does not exist (`ENOSYS`), we retry again below with the
++     * normal `futex` syscall. This can happen if newer kernel headers are
++     * used than the kernel that is actually running.
++     */
++#ifdef __NR_futex
++    if (res >= 0 || errno != ENOSYS) {
++#else
++    {
++#endif
++      success = (res < 0 && errno == ETIMEDOUT) ? FALSE : TRUE;
++      g_mutex_lock (mutex);
++
++      return success;
++    }
++  }
++#endif
++
++#ifdef __NR_futex
++  {
++    struct
++    {
++      __kernel_long_t tv_sec;
++      __kernel_long_t tv_nsec;
++    } end;
++
++    /* Make sure to only ever call this if the end time actually fits into the
++     * target type */
++    g_assert (sizeof (__kernel_long_t) >= 8
++        || end_time / 1000000000 <= G_MAXINT32);
++
++    end.tv_sec = end_time / 1000000000;
++    end.tv_nsec = end_time % 1000000000;
++
++    /* we use FUTEX_WAIT_BITSET_PRIVATE rather than FUTEX_WAIT_PRIVATE to be
++     * able to use absolute time */
++    res =
++        syscall (__NR_futex, cond_val, (gsize) FUTEX_WAIT_BITSET_PRIVATE,
++        (gsize) sampled, &end, NULL, FUTEX_BITSET_MATCH_ANY);
++    success = (res < 0 && errno == ETIMEDOUT) ? FALSE : TRUE;
++    g_mutex_lock (mutex);
++
++    return success;
++  }
++#endif
++
++  /* We can't end up here because of the checks above */
++  g_assert_not_reached ();
+ }
+
+ #elif defined (G_OS_UNIX)
+diff --git a/meson.build b/meson.build
+index 0641f7678b..7331c66150 100644
+--- a/meson.build
++++ b/meson.build
+@@ -294,7 +294,7 @@ if cc.has_header_symbol('pthread.h', 'pthread_cond_timedwait_relative_np')
+ endif
+
+ # Check for futex(2)
+-if cc.links('''#include <linux/futex.h>
++if cc.compiles('''#include <linux/futex.h>
+                #include <sys/syscall.h>
+                #include <unistd.h>
+                int main (int argc, char ** argv) {
+@@ -303,6 +303,15 @@ if cc.links('''#include <linux/futex.h>
+                }''', name : 'futex(2) system call')
+   cdata.set('HAVE_FUTEX', 1)
+ endif
++if cc.compiles('''#include <linux/futex.h>
++               #include <sys/syscall.h>
++               #include <unistd.h>
++               int main (int argc, char ** argv) {
++                 syscall (__NR_futex_time64, NULL, FUTEX_WAKE, FUTEX_WAIT);
++                 return 0;
++               }''', name : 'futex(2) system call')
++  cdata.set('HAVE_FUTEX_TIME64', 1)
++endif
+
+ # Check for posix timers and monotonic clock
+ time_prefix = '#include <time.h>\n'
+-- 
+2.25.1
+

recipes-multimedia/gstreamer/gstreamer1.0_1.20.3.imx.bb

@@ -29,6 +29,7 @@ SRC_URI = "https://gstreamer.freedesktop.org/src/gstreamer/gstreamer-${PV}.tar.x
            file://0003-tests-use-a-dictionaries-for-environment.patch;striplevel=3 \
            file://0004-tests-add-helper-script-to-run-the-installed_tests.patch;striplevel=3 \
            file://0005-tests-remove-gstbin-test_watch_for_state_change-test.patch \
+           file://0006-systemclock-Use-futex_time64-syscall-if-available-32.patch \
            "
 SRC_URI[sha256sum] = "de094a404a3ad8f4977829ea87edf695a4da0b5c8f613ebe54ab414bac89f031"