* [PATCH] linux: always update select timeout (bug 27706)
@ 2021-04-07 13:04 Andreas Schwab
2021-04-07 14:19 ` Adhemerval Zanella
0 siblings, 1 reply; 2+ messages in thread
From: Andreas Schwab @ 2021-04-07 13:04 UTC (permalink / raw)
To: libc-alpha
When select returns, sucessfully or not, the timeout argument should
always be updated with the remaining timeout value. Due to a use of the
wrong function for conversion, that never happend for configurations that
support 64-bit time_t. For other configurations, the timeout was only
updated on sucessful return.
---
sysdeps/unix/sysv/linux/Makefile | 2 +-
sysdeps/unix/sysv/linux/select.c | 6 +-
.../sysv/linux/tst-select-update-timeout.c | 55 +++++++++++++++++++
3 files changed, 59 insertions(+), 4 deletions(-)
create mode 100644 sysdeps/unix/sysv/linux/tst-select-update-timeout.c
diff --git a/sysdeps/unix/sysv/linux/Makefile b/sysdeps/unix/sysv/linux/Makefile
index 303fa297bc..e8524e0483 100644
--- a/sysdeps/unix/sysv/linux/Makefile
+++ b/sysdeps/unix/sysv/linux/Makefile
@@ -109,7 +109,7 @@ tests += tst-clone tst-clone2 tst-clone3 tst-fanotify tst-personality \
tst-tgkill tst-sysvsem-linux tst-sysvmsg-linux tst-sysvshm-linux \
tst-timerfd tst-ppoll tst-futimens tst-utime tst-utimes \
tst-clock_adjtime tst-adjtimex tst-ntp_adjtime tst-ntp_gettime \
- tst-ntp_gettimex tst-sigtimedwait
+ tst-ntp_gettimex tst-sigtimedwait tst-select-update-timeout
# Test for the symbol version of fcntl that was replaced in glibc 2.28.
ifeq ($(have-GLIBC_2.27)$(build-shared),yesyes)
diff --git a/sysdeps/unix/sysv/linux/select.c b/sysdeps/unix/sysv/linux/select.c
index 415aa87d3c..ad3e0ec634 100644
--- a/sysdeps/unix/sysv/linux/select.c
+++ b/sysdeps/unix/sysv/linux/select.c
@@ -55,7 +55,7 @@ __select64 (int nfds, fd_set *readfds, fd_set *writefds, fd_set *exceptfds,
if (r == 0 || errno != ENOSYS)
{
if (timeout != NULL)
- TIMEVAL_TO_TIMESPEC (timeout, &ts64);
+ TIMESPEC_TO_TIMEVAL (timeout, &ts64);
return r;
}
@@ -84,7 +84,7 @@ __select64 (int nfds, fd_set *readfds, fd_set *writefds, fd_set *exceptfds,
r = SYSCALL_CANCEL (pselect6, nfds, readfds, writefds, exceptfds, pts32,
NULL);
# endif
- if (r >= 0 && timeout != NULL)
+ if (timeout != NULL)
*timeout = valid_timespec_to_timeval64 (ts32);
#endif
@@ -105,7 +105,7 @@ __select (int nfds, fd_set *readfds, fd_set *writefds, fd_set *exceptfds,
ptv64 = &tv64;
}
int r = __select64 (nfds, readfds, writefds, exceptfds, ptv64);
- if (r >= 0 && timeout != NULL)
+ if (timeout != NULL)
/* The remanining timeout will be always less the input TIMEOUT. */
*timeout = valid_timeval64_to_timeval (tv64);
return r;
diff --git a/sysdeps/unix/sysv/linux/tst-select-update-timeout.c b/sysdeps/unix/sysv/linux/tst-select-update-timeout.c
new file mode 100644
index 0000000000..454d4e3ada
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/tst-select-update-timeout.c
@@ -0,0 +1,55 @@
+/* Test for select timeout updated after return.
+ Copyright (C) 2021 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <https://www.gnu.org/licenses/>. */
+
+#include <sys/select.h>
+#include <errno.h>
+#include <unistd.h>
+#include <support/check.h>
+#include <support/xsignal.h>
+
+static void
+alarm_handler (int signum)
+{
+ /* Do nothing. */
+}
+
+static int
+do_test (void)
+{
+ /* When select returns, successfully or not, the timeout argument should
+ be updated with the remaining timeout value. */
+
+ struct timeval tv = { .tv_sec = 1 };
+ int r = select (0, NULL, NULL, NULL, &tv);
+ TEST_COMPARE (r, 0);
+ TEST_COMPARE (tv.tv_sec, 0);
+
+ struct sigaction act = { .sa_handler = alarm_handler };
+ xsigaction (SIGALRM, &act, NULL);
+ alarm (2);
+
+ tv.tv_sec = 10;
+ r = select (0, NULL, NULL, NULL, &tv);
+ TEST_COMPARE (r, -1);
+ TEST_COMPARE (errno, EINTR);
+ TEST_VERIFY (tv.tv_sec < 10);
+
+ return 0;
+}
+
+#include <support/test-driver.c>
--
2.31.1
--
Andreas Schwab, SUSE Labs, schwab@suse.de
GPG Key fingerprint = 0196 BAD8 1CE9 1970 F4BE 1748 E4D4 88E3 0EEA B9D7
"And now for something completely different."
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [PATCH] linux: always update select timeout (bug 27706)
2021-04-07 13:04 [PATCH] linux: always update select timeout (bug 27706) Andreas Schwab
@ 2021-04-07 14:19 ` Adhemerval Zanella
0 siblings, 0 replies; 2+ messages in thread
From: Adhemerval Zanella @ 2021-04-07 14:19 UTC (permalink / raw)
To: Andreas Schwab, Adhemerval Zanella via Libc-alpha
On 07/04/2021 10:04, Andreas Schwab wrote:
> When select returns, sucessfully or not, the timeout argument should
> always be updated with the remaining timeout value. Due to a use of the
> wrong function for conversion, that never happend for configurations that
> support 64-bit time_t. For other configurations, the timeout was only
> updated on sucessful return.
Could we the other select fix [1] revised as well? With that I can add
the timeout tests on the generic tests instead of add as Linux
specific.
https://patchwork.sourceware.org/project/glibc/patch/20210331175610.3002618-1-adhemerval.zanella@linaro.org/ ?
> ---
> sysdeps/unix/sysv/linux/Makefile | 2 +-
> sysdeps/unix/sysv/linux/select.c | 6 +-
> .../sysv/linux/tst-select-update-timeout.c | 55 +++++++++++++++++++
> 3 files changed, 59 insertions(+), 4 deletions(-)
> create mode 100644 sysdeps/unix/sysv/linux/tst-select-update-timeout.c
>
> diff --git a/sysdeps/unix/sysv/linux/Makefile b/sysdeps/unix/sysv/linux/Makefile
> index 303fa297bc..e8524e0483 100644
> --- a/sysdeps/unix/sysv/linux/Makefile
> +++ b/sysdeps/unix/sysv/linux/Makefile
> @@ -109,7 +109,7 @@ tests += tst-clone tst-clone2 tst-clone3 tst-fanotify tst-personality \
> tst-tgkill tst-sysvsem-linux tst-sysvmsg-linux tst-sysvshm-linux \
> tst-timerfd tst-ppoll tst-futimens tst-utime tst-utimes \
> tst-clock_adjtime tst-adjtimex tst-ntp_adjtime tst-ntp_gettime \
> - tst-ntp_gettimex tst-sigtimedwait
> + tst-ntp_gettimex tst-sigtimedwait tst-select-update-timeout
>
> # Test for the symbol version of fcntl that was replaced in glibc 2.28.
> ifeq ($(have-GLIBC_2.27)$(build-shared),yesyes)
> diff --git a/sysdeps/unix/sysv/linux/select.c b/sysdeps/unix/sysv/linux/select.c
> index 415aa87d3c..ad3e0ec634 100644
> --- a/sysdeps/unix/sysv/linux/select.c
> +++ b/sysdeps/unix/sysv/linux/select.c
> @@ -55,7 +55,7 @@ __select64 (int nfds, fd_set *readfds, fd_set *writefds, fd_set *exceptfds,
> if (r == 0 || errno != ENOSYS)
> {
> if (timeout != NULL)
> - TIMEVAL_TO_TIMESPEC (timeout, &ts64);
> + TIMESPEC_TO_TIMEVAL (timeout, &ts64);
> return r;
> }
>
> @@ -84,7 +84,7 @@ __select64 (int nfds, fd_set *readfds, fd_set *writefds, fd_set *exceptfds,
> r = SYSCALL_CANCEL (pselect6, nfds, readfds, writefds, exceptfds, pts32,
> NULL);
> # endif
> - if (r >= 0 && timeout != NULL)
> + if (timeout != NULL)
> *timeout = valid_timespec_to_timeval64 (ts32);
> #endif
>
> @@ -105,7 +105,7 @@ __select (int nfds, fd_set *readfds, fd_set *writefds, fd_set *exceptfds,
> ptv64 = &tv64;
> }
> int r = __select64 (nfds, readfds, writefds, exceptfds, ptv64);
> - if (r >= 0 && timeout != NULL)
> + if (timeout != NULL)
> /* The remanining timeout will be always less the input TIMEOUT. */
> *timeout = valid_timeval64_to_timeval (tv64);
> return r;
> diff --git a/sysdeps/unix/sysv/linux/tst-select-update-timeout.c b/sysdeps/unix/sysv/linux/tst-select-update-timeout.c
> new file mode 100644
> index 0000000000..454d4e3ada
> --- /dev/null
> +++ b/sysdeps/unix/sysv/linux/tst-select-update-timeout.c
> @@ -0,0 +1,55 @@
> +/* Test for select timeout updated after return.
> + Copyright (C) 2021 Free Software Foundation, Inc.
> + This file is part of the GNU C Library.
> +
> + The GNU C Library is free software; you can redistribute it and/or
> + modify it under the terms of the GNU Lesser General Public
> + License as published by the Free Software Foundation; either
> + version 2.1 of the License, or (at your option) any later version.
> +
> + The GNU C Library is distributed in the hope that it will be useful,
> + but WITHOUT ANY WARRANTY; without even the implied warranty of
> + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
> + Lesser General Public License for more details.
> +
> + You should have received a copy of the GNU Lesser General Public
> + License along with the GNU C Library; if not, see
> + <https://www.gnu.org/licenses/>. */
> +
> +#include <sys/select.h>
> +#include <errno.h>
> +#include <unistd.h>
> +#include <support/check.h>
> +#include <support/xsignal.h>
> +
> +static void
> +alarm_handler (int signum)
> +{
> + /* Do nothing. */
> +}
> +
> +static int
> +do_test (void)
> +{
> + /* When select returns, successfully or not, the timeout argument should
> + be updated with the remaining timeout value. */
> +
> + struct timeval tv = { .tv_sec = 1 };
> + int r = select (0, NULL, NULL, NULL, &tv);
> + TEST_COMPARE (r, 0);
> + TEST_COMPARE (tv.tv_sec, 0);
> +
> + struct sigaction act = { .sa_handler = alarm_handler };
> + xsigaction (SIGALRM, &act, NULL);
> + alarm (2);
> +
> + tv.tv_sec = 10;
> + r = select (0, NULL, NULL, NULL, &tv);
> + TEST_COMPARE (r, -1);
> + TEST_COMPARE (errno, EINTR);
> + TEST_VERIFY (tv.tv_sec < 10);
> +
> + return 0;
> +}
> +
> +#include <support/test-driver.c>
>
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2021-04-07 13:04 [PATCH] linux: always update select timeout (bug 27706) Andreas Schwab
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