From 95f427178720d047316e95f44777cfdf2ecf2b46 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?P=C3=A1draig=20Brady?= <P@draigBrady.com>
Date: Fri, 4 Jan 2019 09:29:13 -0800
Subject: [PATCH 1/4] tail: don't exit immediately with filters on AIX
* src/tail.c: Fix the check_output_available check on AIX.
Note we don't use poll for all systems as the overhead
of adding the gnulib poll module wouldn't be worth it
just for this single use.
* tests/tail-2/pipe-f.sh: Fix the test which always passed
due to only the exit code of sleep being checked.
* NEWS: Mention the bug fix and rearrange alphabetically.
Fixes http://bugs.gnu.org/33946
Upstream-commit: d5ab4cbe424e3e95140eec22ef828f50b2fb3067
Signed-off-by: Kamil Dudka <kdudka@redhat.com>
---
src/tail.c | 13 +++++++++++++
tests/tail-2/pipe-f.sh | 5 ++++-
2 files changed, 17 insertions(+), 1 deletion(-)
diff --git a/src/tail.c b/src/tail.c
index ac001d7..d63aacc 100644
--- a/src/tail.c
+++ b/src/tail.c
@@ -30,6 +30,9 @@
#include <getopt.h>
#include <sys/types.h>
#include <signal.h>
+#ifdef _AIX
+# include <poll.h>
+#endif
#include "system.h"
#include "argmatch.h"
@@ -335,6 +338,16 @@ named file in a way that accommodates renaming, removal and creation.\n\
static void
check_output_alive (void)
{
+#ifdef _AIX
+ /* select on AIX was seen to give a readable event immediately. */
+ struct pollfd pfd;
+ pfd.fd = STDOUT_FILENO;
+ pfd.events = POLLERR;
+
+ if (poll (&pfd, 1, 0) >= 0 && (pfd.revents & POLLERR))
+ raise (SIGPIPE);
+#endif
+
if (! monitor_output)
return;
diff --git a/tests/tail-2/pipe-f.sh b/tests/tail-2/pipe-f.sh
index 76b0d90..1126c93 100755
--- a/tests/tail-2/pipe-f.sh
+++ b/tests/tail-2/pipe-f.sh
@@ -37,7 +37,10 @@ compare exp out || fail=1
# This would wait indefinitely before v8.28 due to no EPIPE being
# generated due to no data written after the first small amount
-timeout 10 tail -f $mode $fastpoll out | sleep .1 || fail=1
+(returns_ 124 timeout 10 tail -n2 -f $mode $fastpoll out && touch timed_out) |
+ sed 2q > out2
+test -e timed_out && fail=1
+compare exp out2 || fail=1
# This would wait indefinitely before v8.28 (until first write)
(returns_ 1 timeout 10 tail -f $mode $fastpoll /dev/null >&-) || fail=1
--
2.31.1
From 125bb79d3e9f414533b1c29237ee3f647053d0d6 Mon Sep 17 00:00:00 2001
From: Ayappan <ayappap2@in.ibm.com>
Date: Sun, 20 Jan 2019 00:17:33 -0800
Subject: [PATCH 2/4] tail: fix recent ineffective AIX change
* src/tail.c: Fix commit v8.30-40-gd5ab4cb which was ineffective.
Fixes http://bugs.gnu.org/33946
Upstream-commit: 17983b2cb3bccbb4fa69691178caddd99269bda9
Signed-off-by: Kamil Dudka <kdudka@redhat.com>
---
src/tail.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/src/tail.c b/src/tail.c
index d63aacc..9ed6d48 100644
--- a/src/tail.c
+++ b/src/tail.c
@@ -338,6 +338,9 @@ named file in a way that accommodates renaming, removal and creation.\n\
static void
check_output_alive (void)
{
+ if (! monitor_output)
+ return;
+
#ifdef _AIX
/* select on AIX was seen to give a readable event immediately. */
struct pollfd pfd;
@@ -346,11 +349,7 @@ check_output_alive (void)
if (poll (&pfd, 1, 0) >= 0 && (pfd.revents & POLLERR))
raise (SIGPIPE);
-#endif
-
- if (! monitor_output)
- return;
-
+#else
struct timeval delay;
delay.tv_sec = delay.tv_usec = 0;
@@ -362,6 +361,7 @@ check_output_alive (void)
and implies an error condition on output like broken pipe. */
if (select (STDOUT_FILENO + 1, &rfd, NULL, NULL, &delay) == 1)
raise (SIGPIPE);
+#endif
}
static bool
--
2.31.1
From 7741989c3e633aa44f01d8f91332cb65a9280ba3 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?P=C3=A1draig=20Brady?= <P@draigBrady.com>
Date: Sun, 20 Jan 2019 00:13:15 -0800
Subject: [PATCH 3/4] tail: fix handling of broken pipes with SIGPIPE ignored
* init.cfg (trap_sigpipe_or_skip_): A new function refactored from...
* tests/misc/printf-surprise.sh: ...here.
* tests/misc/seq-epipe.sh. Likewise.
* src/tail.c (die_pipe): Ensure we exit upon sending SIGPIPE.
* tests/tail-2/pipe-f.sh: Ensure we exit even if SIGPIPE is ignored.
* NEWS: Mention the bug fix.
Upstream-commit: fa50623394f491b975dbd7ad73193519dd721771
Signed-off-by: Kamil Dudka <kdudka@redhat.com>
---
init.cfg | 6 ++++++
src/tail.c | 14 +++++++++++---
tests/misc/printf-surprise.sh | 4 +---
tests/misc/seq-epipe.sh | 4 +---
tests/tail-2/pipe-f.sh | 19 ++++++++++++++-----
5 files changed, 33 insertions(+), 14 deletions(-)
diff --git a/init.cfg b/init.cfg
index b6c81ab..985c8d3 100644
--- a/init.cfg
+++ b/init.cfg
@@ -613,6 +613,12 @@ mkfifo_or_skip_()
fi
}
+trap_sigpipe_or_skip_()
+{
+ (trap '' PIPE && yes | :) 2>&1 | grep -qF 'Broken pipe' ||
+ skip_ 'trapping SIGPIPE is not supported'
+}
+
# Disable the current test if the working directory seems to have
# the setgid bit set.
skip_if_setgid_()
diff --git a/src/tail.c b/src/tail.c
index 9ed6d48..16e0d73 100644
--- a/src/tail.c
+++ b/src/tail.c
@@ -333,6 +333,14 @@ named file in a way that accommodates renaming, removal and creation.\n\
exit (status);
}
+/* Ensure exit, either with SIGPIPE or EXIT_FAILURE status. */
+static void ATTRIBUTE_NORETURN
+die_pipe (void)
+{
+ raise (SIGPIPE);
+ exit (EXIT_FAILURE);
+}
+
/* If the output has gone away, then terminate
as we would if we had written to this output. */
static void
@@ -348,7 +356,7 @@ check_output_alive (void)
pfd.events = POLLERR;
if (poll (&pfd, 1, 0) >= 0 && (pfd.revents & POLLERR))
- raise (SIGPIPE);
+ die_pipe ();
#else
struct timeval delay;
delay.tv_sec = delay.tv_usec = 0;
@@ -360,7 +368,7 @@ check_output_alive (void)
/* readable event on STDOUT is equivalent to POLLERR,
and implies an error condition on output like broken pipe. */
if (select (STDOUT_FILENO + 1, &rfd, NULL, NULL, &delay) == 1)
- raise (SIGPIPE);
+ die_pipe ();
#endif
}
@@ -1658,7 +1666,7 @@ tail_forever_inotify (int wd, struct File_spec *f, size_t n_files,
{
/* readable event on STDOUT is equivalent to POLLERR,
and implies an error on output like broken pipe. */
- raise (SIGPIPE);
+ die_pipe ();
}
else
break;
diff --git a/tests/misc/printf-surprise.sh b/tests/misc/printf-surprise.sh
index fd88133..acac0b1 100755
--- a/tests/misc/printf-surprise.sh
+++ b/tests/misc/printf-surprise.sh
@@ -49,9 +49,7 @@ vm=$(get_min_ulimit_v_ env $prog %20f 0) \
# triggering the printf(3) misbehavior -- which, btw, is required by ISO C99.
mkfifo_or_skip_ fifo
-
-(trap '' PIPE && yes | :) 2>&1 | grep -qF 'Broken pipe' ||
- skip_ 'trapping SIGPIPE is not supported'
+trap_sigpipe_or_skip_
# Disable MALLOC_PERTURB_, to avoid triggering this bug
# https://bugs.debian.org/481543#77
diff --git a/tests/misc/seq-epipe.sh b/tests/misc/seq-epipe.sh
index 3e89158..127d61c 100755
--- a/tests/misc/seq-epipe.sh
+++ b/tests/misc/seq-epipe.sh
@@ -18,9 +18,7 @@
. "${srcdir=.}/tests/init.sh"; path_prepend_ ./src
print_ver_ seq
-
-(trap '' PIPE && yes | :) 2>&1 | grep -qF 'Broken pipe' ||
- skip_ 'trapping SIGPIPE is not supported'
+trap_sigpipe_or_skip_
# upon EPIPE with signals ignored, 'seq' should exit with an error.
timeout 10 sh -c \
diff --git a/tests/tail-2/pipe-f.sh b/tests/tail-2/pipe-f.sh
index 1126c93..f734a61 100755
--- a/tests/tail-2/pipe-f.sh
+++ b/tests/tail-2/pipe-f.sh
@@ -18,6 +18,7 @@
. "${srcdir=.}/tests/init.sh"; path_prepend_ ./src
print_ver_ tail
+trap_sigpipe_or_skip_
# Speedup the non inotify case
fastpoll='-s.1 --max-unchanged-stats=1'
@@ -36,11 +37,19 @@ echo bar | returns_ 1 \
compare exp out || fail=1
# This would wait indefinitely before v8.28 due to no EPIPE being
-# generated due to no data written after the first small amount
-(returns_ 124 timeout 10 tail -n2 -f $mode $fastpoll out && touch timed_out) |
- sed 2q > out2
-test -e timed_out && fail=1
-compare exp out2 || fail=1
+# generated due to no data written after the first small amount.
+# Also check tail exits if SIGPIPE is being ignored.
+# Note 'trap - SIGPIPE' is ineffective if the initiating shell
+# has ignored SIGPIPE, but that's not the normal case.
+for disposition in '' '-'; do
+ (trap "$disposition" PIPE;
+ returns_ 124 timeout 10 \
+ tail -n2 -f $mode $fastpoll out && touch timed_out) |
+ sed 2q > out2
+ test -e timed_out && fail=1
+ compare exp out2 || fail=1
+ rm -f timed_out
+done
# This would wait indefinitely before v8.28 (until first write)
(returns_ 1 timeout 10 tail -f $mode $fastpoll /dev/null >&-) || fail=1
--
2.31.1
From 0f5760466d167e955d28a1250ffd0af347d48dc9 Mon Sep 17 00:00:00 2001
From: Paul Eggert <eggert@cs.ucla.edu>
Date: Sat, 26 Jun 2021 18:23:52 -0700
Subject: [PATCH 4/4] tail: use poll, not select
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
This fixes an unlikely stack out-of-bounds write reported by
Stepan Broz via Kamil Dudka (Bug#49209).
* src/tail.c: Do not include <sys/select.h>.
[!_AIX]: Include poll.h.
(check_output_alive) [!_AIX]: Use poll instead of select.
(tail_forever_inotify): Likewise. Simplify logic, as there is no
need for a ‘while (len <= evbuf_off)’ loop.
Upstream-commit: da0d448bca62c6305fc432f67e2c5ccc2da75346
Signed-off-by: Kamil Dudka <kdudka@redhat.com>
---
src/tail.c | 101 +++++++++++++++++++++--------------------------------
1 file changed, 39 insertions(+), 62 deletions(-)
diff --git a/src/tail.c b/src/tail.c
index 16e0d73..d77c660 100644
--- a/src/tail.c
+++ b/src/tail.c
@@ -29,10 +29,8 @@
#include <assert.h>
#include <getopt.h>
#include <sys/types.h>
+#include <poll.h>
#include <signal.h>
-#ifdef _AIX
-# include <poll.h>
-#endif
#include "system.h"
#include "argmatch.h"
@@ -55,8 +53,6 @@
#if HAVE_INOTIFY
# include "hash.h"
# include <sys/inotify.h>
-/* 'select' is used by tail_forever_inotify. */
-# include <sys/select.h>
/* inotify needs to know if a file is local. */
# include "fs.h"
@@ -349,27 +345,12 @@ check_output_alive (void)
if (! monitor_output)
return;
-#ifdef _AIX
- /* select on AIX was seen to give a readable event immediately. */
struct pollfd pfd;
pfd.fd = STDOUT_FILENO;
pfd.events = POLLERR;
if (poll (&pfd, 1, 0) >= 0 && (pfd.revents & POLLERR))
die_pipe ();
-#else
- struct timeval delay;
- delay.tv_sec = delay.tv_usec = 0;
-
- fd_set rfd;
- FD_ZERO (&rfd);
- FD_SET (STDOUT_FILENO, &rfd);
-
- /* readable event on STDOUT is equivalent to POLLERR,
- and implies an error condition on output like broken pipe. */
- if (select (STDOUT_FILENO + 1, &rfd, NULL, NULL, &delay) == 1)
- die_pipe ();
-#endif
}
static bool
@@ -1609,7 +1590,7 @@ tail_forever_inotify (int wd, struct File_spec *f, size_t n_files,
/* Wait for inotify events and handle them. Events on directories
ensure that watched files can be re-added when following by name.
This loop blocks on the 'safe_read' call until a new event is notified.
- But when --pid=P is specified, tail usually waits via the select. */
+ But when --pid=P is specified, tail usually waits via poll. */
while (1)
{
struct File_spec *fspec;
@@ -1626,54 +1607,51 @@ tail_forever_inotify (int wd, struct File_spec *f, size_t n_files,
return false;
}
- /* When watching a PID, ensure that a read from WD will not block
- indefinitely. */
- while (len <= evbuf_off)
+ if (len <= evbuf_off)
{
- struct timeval delay; /* how long to wait for file changes. */
+ /* Poll for inotify events. When watching a PID, ensure
+ that a read from WD will not block indefinitely.
+ If MONITOR_OUTPUT, also poll for a broken output pipe. */
- if (pid)
+ int file_change;
+ struct pollfd pfd[2];
+ do
{
- if (writer_is_dead)
- exit (EXIT_SUCCESS);
+ /* How many ms to wait for changes. -1 means wait forever. */
+ int delay = -1;
- writer_is_dead = (kill (pid, 0) != 0 && errno != EPERM);
-
- if (writer_is_dead)
- delay.tv_sec = delay.tv_usec = 0;
- else
+ if (pid)
{
- delay.tv_sec = (time_t) sleep_interval;
- delay.tv_usec = 1000000 * (sleep_interval - delay.tv_sec);
+ if (writer_is_dead)
+ exit (EXIT_SUCCESS);
+
+ writer_is_dead = (kill (pid, 0) != 0 && errno != EPERM);
+
+ if (writer_is_dead || sleep_interval <= 0)
+ delay = 0;
+ else if (sleep_interval < INT_MAX / 1000 - 1)
+ {
+ /* delay = ceil (sleep_interval * 1000), sans libm. */
+ double ddelay = sleep_interval * 1000;
+ delay = ddelay;
+ delay += delay < ddelay;
+ }
}
+
+ pfd[0].fd = wd;
+ pfd[0].events = POLLIN;
+ pfd[1].fd = STDOUT_FILENO;
+ pfd[1].events = pfd[1].revents = 0;
+ file_change = poll (pfd, monitor_output + 1, delay);
}
+ while (file_change == 0);
- fd_set rfd;
- FD_ZERO (&rfd);
- FD_SET (wd, &rfd);
- if (monitor_output)
- FD_SET (STDOUT_FILENO, &rfd);
-
- int file_change = select (MAX (wd, STDOUT_FILENO) + 1,
- &rfd, NULL, NULL, pid ? &delay: NULL);
-
- if (file_change == 0)
- continue;
- else if (file_change == -1)
- die (EXIT_FAILURE, errno,
- _("error waiting for inotify and output events"));
- else if (FD_ISSET (STDOUT_FILENO, &rfd))
- {
- /* readable event on STDOUT is equivalent to POLLERR,
- and implies an error on output like broken pipe. */
- die_pipe ();
- }
- else
- break;
- }
+ if (file_change < 0)
+ die (EXIT_FAILURE, errno,
+ _("error waiting for inotify and output events"));
+ if (pfd[1].revents)
+ die_pipe ();
- if (len <= evbuf_off)
- {
len = safe_read (wd, evbuf, evlen);
evbuf_off = 0;
@@ -2434,8 +2412,7 @@ main (int argc, char **argv)
if (forever && ignore_fifo_and_pipe (F, n_files))
{
/* If stdout is a fifo or pipe, then monitor it
- so that we exit if the reader goes away.
- Note select() on a regular file is always readable. */
+ so that we exit if the reader goes away. */
struct stat out_stat;
if (fstat (STDOUT_FILENO, &out_stat) < 0)
die (EXIT_FAILURE, errno, _("standard output"));
--
2.31.1