From cb306a8f174bec9ded95191b91797f59250e6808 Mon Sep 17 00:00:00 2001
From: Peter Hutterer <peter.hutterer@who-t.net>
Date: Tue, 31 Jul 2012 16:09:38 +1000
Subject: [PATCH 1/2] dix: make sure the mask is set for emulated scroll events
 (#52508)

If a device has smooth scrolling axes, but submits scroll button events, we
convert those to motion events and update the valuators. For legacy button
events, the valuator mask is likely unset though, causing
add_to_scroll_valuator() to return early, leaving us with an empty mask.
That again skipped the rest of the code and no events were generated.

Fix it by making sure that the scroll valuator in the mask is at least
initialized to 0.

Broke evdev wheel emulation, introduced by
54476b5e4461ff523e935961affabcf0de12c556.

X.Org Bug 52508 <http://bugs.freedesktop.org/show_bug.cgi?id=52508>

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
Reviewed-by: Chase Douglas <chase.douglas@canonical.com>
---
 dix/getevents.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/dix/getevents.c b/dix/getevents.c
index 27c2e04d1..b3bb162ae 100644
--- a/dix/getevents.c
+++ b/dix/getevents.c
@@ -1625,6 +1625,8 @@ GetPointerEvents(InternalEvent *events, DeviceIntPtr pDev, int type,
 
         if (adj != 0.0 && axis != -1) {
             adj *= pDev->valuator->axes[axis].scroll.increment;
+            if (!valuator_mask_isset(&mask, axis))
+                valuator_mask_set(&mask, axis, 0);
             add_to_scroll_valuator(pDev, &mask, axis, adj);
             type = MotionNotify;
             buttons = 0;

From 7f09126e068015db54c56bb982b8f91065375700 Mon Sep 17 00:00:00 2001
From: Peter Hutterer <peter.hutterer@who-t.net>
Date: Fri, 3 Aug 2012 15:36:34 +1000
Subject: [PATCH 2/2] os: don't unconditionally unblock SIGIO in
 OsReleaseSignals()

Calling OsReleaseSignal() inside the signal handler releases SIGIO, causing
the signal handler to be called again from within the handler.

Practical use-case: when synaptics calls TimerSet in the signal handler,
this causes the signals to be released, eventually hanging the server.

Regression introduced in 08962951de.

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
Reviewed-by: Jeremy Huddleston <jeremyhu@apple.com>
---
 os/utils.c | 13 +++++--------
 test/os.c  | 36 ++++++++++++++++++++++++++++++++++++
 2 files changed, 41 insertions(+), 8 deletions(-)

diff --git a/os/utils.c b/os/utils.c
index cdf5fd82e..947f8673a 100644
--- a/os/utils.c
+++ b/os/utils.c
@@ -1186,6 +1186,7 @@ OsBlockSignals(void)
 
 #ifdef SIG_BLOCK
 static sig_atomic_t sigio_blocked;
+static sigset_t PreviousSigIOMask;
 #endif
 
 /**
@@ -1198,13 +1199,13 @@ OsBlockSIGIO(void)
 #ifdef SIGIO
 #ifdef SIG_BLOCK
     if (sigio_blocked++ == 0) {
-        sigset_t set, old;
+        sigset_t set;
         int ret;
 
         sigemptyset(&set);
         sigaddset(&set, SIGIO);
-        sigprocmask(SIG_BLOCK, &set, &old);
-        ret = sigismember(&old, SIGIO);
+        sigprocmask(SIG_BLOCK, &set, &PreviousSigIOMask);
+        ret = sigismember(&PreviousSigIOMask, SIGIO);
         return ret;
     } else
         return 1;
@@ -1218,11 +1219,7 @@ OsReleaseSIGIO(void)
 #ifdef SIGIO
 #ifdef SIG_BLOCK
     if (--sigio_blocked == 0) {
-        sigset_t set;
-
-        sigemptyset(&set);
-        sigaddset(&set, SIGIO);
-        sigprocmask(SIG_UNBLOCK, &set, NULL);
+        sigprocmask(SIG_SETMASK, &PreviousSigIOMask, 0);
     } else if (sigio_blocked < 0) {
         BUG_WARN(sigio_blocked < 0);
         sigio_blocked = 0;
diff --git a/test/os.c b/test/os.c
index 1460a34d6..8f1107ded 100644
--- a/test/os.c
+++ b/test/os.c
@@ -28,6 +28,21 @@
 #include <signal.h>
 #include "os.h"
 
+static int last_signal = 0;
+static int expect_signal = 0;
+
+static void sighandler(int signal)
+{
+    assert(expect_signal);
+    expect_signal = 0;
+    if (!last_signal)
+        raise(signal);
+    OsBlockSignals();
+    OsReleaseSignals();
+    last_signal = 1;
+    expect_signal = 1;
+}
+
 static int
 sig_is_blocked(int sig)
 {
@@ -118,7 +133,27 @@ static void block_sigio_test(void)
     assert(sig_is_blocked(SIGIO));
     OsReleaseSignals();
     assert(!sig_is_blocked(SIGIO));
+#endif
+}
 
+static void block_sigio_test_nested(void)
+{
+#ifdef SIG_BLOCK
+    /* Check for bug releasing SIGIO during SIGIO signal handling.
+       test case:
+           raise signal
+           → in signal handler:
+                raise signal
+                OsBlockSignals()
+                OsReleaseSignals()
+                tail guard
+       tail guard must be hit.
+     */
+    sighandler_t old_handler;
+    old_handler = signal(SIGIO, sighandler);
+    expect_signal = 1;
+    assert(raise(SIGIO) == 0);
+    assert(signal(SIGIO, old_handler) == sighandler);
 #endif
 }
 
@@ -126,5 +161,6 @@ int
 main(int argc, char **argv)
 {
     block_sigio_test();
+    block_sigio_test_nested();
     return 0;
 }