user/gstreamer: Fix for time64 issue

The patch fixes #853 (libs_gstnetclientclock).

The glib-2.72.4 update is actually what fixed #874, as futex was broken
on 32-bit architectures.  It was affecting PowerPC harder because the
MSB was what the kernel was seeing, but in 2038 the other arches would
have started seeing the same failures.

Fixes: #853, #874

1 files changed, 60 insertions, 0 deletions

diff --git a/user/gstreamer/time64.patch b/user/gstreamer/time64.patch
new file mode 100644
index 000000000..89c88c380
--- /dev/null
+++ b/user/gstreamer/time64.patch
@@ -0,0 +1,60 @@
+From 664fc63a246cba97e202f712aa48105f46a9ff69 Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Sebastian=20Dr=C3=B6ge?= <sebastian@centricular.com>
+Date: Mon, 12 Dec 2022 11:34:51 +0200
+Subject: [PATCH] systemclock: Use `futex_time64` syscall on x32 and other
+ platforms that always use a 32-bit `struct timespec` for the normal `futex`
+ syscall
+
+See also https://gitlab.gnome.org/GNOME/glib/-/issues/2634
+---
+ gst/gstsystemclock.c | 26 +++++++++++++++++++++-
+ 1 file changed, 25 insertions(+), 1 deletion(-)
+
+diff --git a/gst/gstsystemclock.c b/gst/gstsystemclock.c
+index 6d0b6ec47b6..8c396d2c7b4 100644
+--- a/gst/gstsystemclock.c
++++ b/gst/gstsystemclock.c
+@@ -130,7 +130,31 @@ gst_futex_cond_broadcast (guint * cond_val)
+ static gboolean
+ gst_futex_cond_wait_until (guint * cond_val, GMutex * mutex, gint64 end_time)
+ {
++  /* On x32 (ILP32 ABI on x86_64) and potentially sparc64, the raw futex()
++   * syscall takes a 32-bit timespan argument *regardless* of whether userspace
++   * is using 32-bit or 64-bit `struct timespec`. This means that we can’t
++   * unconditionally pass a `struct timespec` pointer into the syscall.
++   *
++   * Assume that any such platform is new enough to define the
++   * `__NR_futex_time64` workaround syscall (which accepts 64-bit timespecs,
++   * introduced in kernel 5.1), and use that to pass a 64-bit timespec instead.
++   *
++   * `clock_gettime()` on such systems will either return a 32-bit `struct
++   * timespec`, in which case the values we will get passed in here are
++   * already not y2038-safe, or `struct timespec` is using 64-bit `time_t` and
++   * everything is fine.
++   */
++#ifdef __NR_futex_time64
++  struct
++  {
++    gint64 tv_sec;
++    gint64 tv_nsec;
++  } end;
++  const long int futex_syscall_id = __NR_futex_time64;
++#else
+   struct timespec end;
++  const long int futex_syscall_id = __NR_futex;
++#endif
+   guint sampled;
+   int res;
+   gboolean success;
+@@ -146,7 +170,7 @@ gst_futex_cond_wait_until (guint * cond_val, GMutex * mutex, gint64 end_time)
+   /* 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,
++      syscall (futex_syscall_id, 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);
+-- 
+GitLab
+