handle EINTR when waiting for transmit timestamp (#2123224)

Resolves: #2123224

linuxptp-eintr.patch

@@ -0,0 +1,30 @@
+commit b8ecf4ddd6533437020c4589a6f7bcd9a62307ad
+Author: Miroslav Lichvar <mlichvar@redhat.com>
+Date:   Tue Sep 13 13:44:10 2022 +0200
+
+    sk: Handle EINTR when waiting for transmit timestamp.
+    
+    If ptp4l received a signal in poll() waiting for a transmit timestamp,
+    multiple (possibly confusing) error messages are logged before exit.
+    
+    If poll() returns with EINTR, call it once again to get the timestamp
+    and avoid logging the errors. Don't call it in a loop to avoid getting
+    stuck in case the timestamp is lost and the signal is repeated before
+    the poll timeout can be reached.
+    
+    Signed-off-by: Miroslav Lichvar <mlichvar@redhat.com>
+
+diff --git a/sk.c b/sk.c
+index 8be0708..3595649 100644
+--- a/sk.c
++++ b/sk.c
+@@ -349,6 +349,9 @@ int sk_receive(int fd, void *buf, int buflen,
+ 	if (flags == MSG_ERRQUEUE) {
+ 		struct pollfd pfd = { fd, sk_events, 0 };
+ 		res = poll(&pfd, 1, sk_tx_timeout);
++		/* Retry once on EINTR to avoid logging errors before exit */
++		if (res < 0 && errno == EINTR)
++			res = poll(&pfd, 1, sk_tx_timeout);
+ 		if (res < 1) {
+ 			pr_err(res ? "poll for tx timestamp failed: %m" :
+ 			             "timed out while polling for tx timestamp");

linuxptp.spec

@@ -41,6 +41,8 @@ Patch9:		linuxptp-zerolength.patch
 Patch10:	linuxptp-clockcheck.patch
 # handle PHC read failing with EBUSY in phc2sys
 Patch11:	linuxptp-phcerr.patch
+# handle EINTR when waiting for transmit timestamp
+Patch15:	linuxptp-eintr.patch
 # don't re-arm fault clearing timer on unrelated netlink events
 Patch17:	linuxptp-faultrearm.patch
 
@@ -68,6 +70,7 @@ Supporting legacy APIs and other platforms is not a goal.
 %patch9 -p1 -b .zerolength
 %patch10 -p1 -b .clockcheck
 %patch11 -p1 -b .phcerr
+%patch15 -p1 -b .eintr
 %patch17 -p1 -b .faultrearm
 mv linuxptp-testsuite-%{testsuite_ver}* testsuite
 mv clknetsim-%{clknetsim_ver}* testsuite/clknetsim