git: 3109a31bf21b - stable/13 - tail: Retry kevent if the system call was interrupted

The branch stable/13 has been updated by des:

URL: https://cgit.FreeBSD.org/src/commit/?id=3109a31bf21b50aded5f27900e7a58490daeac48

commit 3109a31bf21b50aded5f27900e7a58490daeac48
Author:     Warner Losh <imp@FreeBSD.org>
AuthorDate: 2023-02-19 03:04:29 +0000
Commit:     Dag-Erling Smørgrav <des@FreeBSD.org>
CommitDate: 2023-12-13 16:39:38 +0000

    tail: Retry kevent if the system call was interrupted
    
    kevent returns EINTR when I suspend / resume. This causes tail -f
    and tail -F to exit with interrupt system call. Ignore this error
    and try kevent again.
    
    Sponsored by:           Netflix
    
    (cherry picked from commit ef6f20ce47613db7cc615b45f4b6fa1eb99ae0ba)
---
 usr.bin/tail/forward.c | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/usr.bin/tail/forward.c b/usr.bin/tail/forward.c
index f991b2517c48..e2a3eb77aade 100644
--- a/usr.bin/tail/forward.c
+++ b/usr.bin/tail/forward.c
@@ -408,10 +408,16 @@ follow(file_info_t *files, enum STYLE style, off_t off)
 			/*
 			 * In the -F case we set a timeout to ensure that
 			 * we re-stat the file at least once every second.
+			 * If we've recieved EINTR, ignore it. Both reasons
+			 * for its generation are transient.
 			 */
-			n = kevent(kq, NULL, 0, ev, 1, Fflag ? &ts : NULL);
-			if (n < 0)
-				err(1, "kevent");
+			do {
+				n = kevent(kq, NULL, 0, ev, 1, Fflag ? &ts : NULL);
+				if (n < 0 && errno == EINTR)
+					continue;
+				if (n < 0)
+					err(1, "kevent");
+			} while (n < 0);
 			if (n == 0) {
 				/* timeout */
 				break;