more(1): make sure we have data on stderr

Resolves: RHEL-55725

0004-more-make-sure-we-have-data-on-stderr.patch

@@ -0,0 +1,97 @@
+From ddadbe77a79d46e5bf8ff279ba5aa14573653d16 Mon Sep 17 00:00:00 2001
+From: Karel Zak <kzak@redhat.com>
+Date: Thu, 22 Aug 2024 08:56:52 +0200
+Subject: more: make sure we have data on stderr
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+more(1) uses more_poll() to monitor data on stdin, stderr, and
+signals. It is used before read_command(), but this function only
+reads from stderr. Therefore, if any other non-stderr event occurs,
+this function will wait on read(). In this case, more(1) will not
+react to signals anymore. We need to ensure that more(1) only waits in
+more_poll().
+
+Try
+
+ for x in {1..1000}; do echo "line $x"; done | more
+
+to reproduce.
+
+Addresses: https://issues.redhat.com/browse/RHEL-55725
+Reported-by: Radka Skvarilova <rskvaril@redhat.com>
+Signed-off-by: Karel Zak <kzak@redhat.com>
+(cherry picked from commit 640b9480bd3efc0f4bc7f38a785d02cda70ec5c3)
+---
+ text-utils/more.c | 18 +++++++++++++-----
+ 1 file changed, 13 insertions(+), 5 deletions(-)
+
+diff --git a/text-utils/more.c b/text-utils/more.c
+index 1badf67d5..38a226638 100644
+--- a/text-utils/more.c
++++ b/text-utils/more.c
+@@ -1350,7 +1350,7 @@ static void read_line(struct more_control *ctl)
+ }
+ 
+ /* returns: 0 timeout or nothing; <0 error, >0 success */
+-static int more_poll(struct more_control *ctl, int timeout)
++static int more_poll(struct more_control *ctl, int timeout, int *stderr_active)
+ {
+ 	enum {
+ 		POLLFD_SIGNAL = 0,
+@@ -1364,6 +1364,9 @@ static int more_poll(struct more_control *ctl, int timeout)
+ 	};
+ 	int has_data = 0;
+ 
++	if (stderr_active)
++		*stderr_active = 0;
++
+ 	while (!has_data) {
+ 		int rc;
+ 
+@@ -1430,8 +1433,11 @@ static int more_poll(struct more_control *ctl, int timeout)
+ 		}
+ 
+ 		/* event on stderr (we reads user commands from stderr!) */
+-		if (pfd[POLLFD_STDERR].revents)
++		if (pfd[POLLFD_STDERR].revents) {
+ 			has_data++;
++			if (stderr_active)
++				*stderr_active = 1;
++		}
+ 	}
+ 
+ 	return has_data;
+@@ -1502,7 +1508,7 @@ static void search(struct more_control *ctl, char buf[], int n)
+ 			}
+ 			break;
+ 		}
+-		more_poll(ctl, 0);
++		more_poll(ctl, 0, NULL);
+ 	}
+ 	/* Move ctrl+c signal handling back to more_key_command(). */
+ 	signal(SIGINT, SIG_DFL);
+@@ -1656,7 +1662,7 @@ static int skip_forwards(struct more_control *ctl, int nlines, cc_t comchar)
+ static int more_key_command(struct more_control *ctl, char *filename)
+ {
+ 	int retval = 0;
+-	int done = 0, search_again = 0;
++	int done = 0, search_again = 0, stderr_active = 0;
+ 	char cmdbuf[INIT_BUF];
+ 	struct number_command cmd;
+ 
+@@ -1666,7 +1672,9 @@ static int more_key_command(struct more_control *ctl, char *filename)
+ 		ctl->report_errors = 0;
+ 	ctl->search_called = 0;
+ 	for (;;) {
+-		if (more_poll(ctl, -1) <= 0)
++		if (more_poll(ctl, -1, &stderr_active) <= 0)
++			continue;
++		if (stderr_active == 0)
+ 			continue;
+ 		cmd = read_command(ctl);
+ 		if (cmd.key == more_kc_unknown_command)
+-- 
+2.47.1
+

util-linux.spec

@@ -99,9 +99,11 @@ Patch0: 0000-login-lastlog-create.patch
 # https://github.com/coreos/console-login-helper-messages/issues/60
 Patch1: 0001-login-default-motd-file.patch
 
-# upstream
+# Upstream
 Patch2: 0002-uuidd-fix-var-lib-libuuid-mode-uuidd-tmpfiles.conf.patch
 Patch3: 0003-uuidd-fix-typo-in-tmpfiles.conf.patch
+# RHEL-55725 - more: make sure we have data on stderr
+Patch4: 0004-more-make-sure-we-have-data-on-stderr.patch
 
 
 %description