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

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Resolves: RHEL-55725
This commit is contained in:
Karel Zak 2025-01-14 12:01:53 +01:00
parent 2dd965c4d8
commit 462a2bd284
2 changed files with 100 additions and 1 deletions
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97
0004-more-make-sure-we-have-data-on-stderr.patch Normal file
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@ -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

4
util-linux.spec
View File

@ -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