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[v2,2/2] linux: always update select timeout (BZ #27706)

Message ID 20210409113639.1124756-2-adhemerval.zanella@linaro.org
State Superseded
Headers show
Series [v2,1/2] linux: Normalize and return timeout on select (BZ #27651) | expand

Commit Message

Adhemerval Zanella April 9, 2021, 11:36 a.m. UTC
The timeout should be updated even on failure for time64 support.

Checked on i686-linux-gnu.
---
 misc/tst-select.c                | 30 ++++++++++++++++++++++++++++++
 sysdeps/unix/sysv/linux/select.c |  4 ++--
 2 files changed, 32 insertions(+), 2 deletions(-)

Comments

Florian Weimer April 9, 2021, 12:26 p.m. UTC | #1
* Adhemerval Zanella via Libc-alpha:

> diff --git a/misc/tst-select.c b/misc/tst-select.c
> index dc7717a7a6..9c817f4035 100644
> --- a/misc/tst-select.c
> +++ b/misc/tst-select.c
> @@ -23,6 +23,7 @@
>  #include <support/timespec.h>
>  #include <support/xunistd.h>
>  #include <support/xtime.h>
> +#include <support/xsignal.h>
>  
>  struct child_args
>  {
> @@ -30,6 +31,12 @@ struct child_args
>    struct timeval tmo;
>  };
>  
> +static void
> +alarm_handler (int signum)
> +{
> +  /* Do nothing.  */
> +}
> +
>  static void
>  do_test_child (void *clousure)
>  {
> @@ -59,6 +66,22 @@ do_test_child (void *clousure)
>    xwrite (args->fds[1][1], "foo", 3);
>  }
>  
> +static void
> +do_test_child_alarm (void *clousure)
> +{
> +  struct sigaction act = { .sa_handler = alarm_handler };
> +  xsigaction (SIGALRM, &act, NULL);
> +  alarm (1);
> +
> +  struct timeval tv = { .tv_sec = 10, .tv_usec = 0 };
> +  int r = select (0, NULL, NULL, NULL, &tv);
> +  TEST_COMPARE (r, -1);
> +  TEST_COMPARE (errno, EINTR);
> +
> +  if (support_select_modify_timeout ())
> +    TEST_VERIFY (tv.tv_sec < 10);
> +}
> +
>  static int
>  do_test (void)
>  {
> @@ -98,6 +121,13 @@ do_test (void)
>    xclose (args.fds[0][0]);
>    xclose (args.fds[1][1]);
>  
> +  {
> +    struct support_capture_subprocess result;
> +    result = support_capture_subprocess (do_test_child_alarm, NULL);
> +    support_capture_subprocess_check (&result, "tst-select-child", 0,
> +				      sc_allow_none);
> +  }
> +
>    {
>      fd_set rfds;
>      FD_ZERO (&rfds);

I thought a bit about how this would interact with SIGALRM in the test
suite, but this should be okay: the SIGALRM handler is in the parent
wrapper process, not in the child process, and in --direct mode (without
a wrapper), there is no timeout at all.  So the test should be okay.

The actual code change looks okay to me too.

Thanks,
Florian
diff mbox series

Patch

diff --git a/misc/tst-select.c b/misc/tst-select.c
index dc7717a7a6..9c817f4035 100644
--- a/misc/tst-select.c
+++ b/misc/tst-select.c
@@ -23,6 +23,7 @@ 
 #include <support/timespec.h>
 #include <support/xunistd.h>
 #include <support/xtime.h>
+#include <support/xsignal.h>
 
 struct child_args
 {
@@ -30,6 +31,12 @@  struct child_args
   struct timeval tmo;
 };
 
+static void
+alarm_handler (int signum)
+{
+  /* Do nothing.  */
+}
+
 static void
 do_test_child (void *clousure)
 {
@@ -59,6 +66,22 @@  do_test_child (void *clousure)
   xwrite (args->fds[1][1], "foo", 3);
 }
 
+static void
+do_test_child_alarm (void *clousure)
+{
+  struct sigaction act = { .sa_handler = alarm_handler };
+  xsigaction (SIGALRM, &act, NULL);
+  alarm (1);
+
+  struct timeval tv = { .tv_sec = 10, .tv_usec = 0 };
+  int r = select (0, NULL, NULL, NULL, &tv);
+  TEST_COMPARE (r, -1);
+  TEST_COMPARE (errno, EINTR);
+
+  if (support_select_modify_timeout ())
+    TEST_VERIFY (tv.tv_sec < 10);
+}
+
 static int
 do_test (void)
 {
@@ -98,6 +121,13 @@  do_test (void)
   xclose (args.fds[0][0]);
   xclose (args.fds[1][1]);
 
+  {
+    struct support_capture_subprocess result;
+    result = support_capture_subprocess (do_test_child_alarm, NULL);
+    support_capture_subprocess_check (&result, "tst-select-child", 0,
+				      sc_allow_none);
+  }
+
   {
     fd_set rfds;
     FD_ZERO (&rfds);
diff --git a/sysdeps/unix/sysv/linux/select.c b/sysdeps/unix/sysv/linux/select.c
index d075270ff4..4e426f9aed 100644
--- a/sysdeps/unix/sysv/linux/select.c
+++ b/sysdeps/unix/sysv/linux/select.c
@@ -110,7 +110,7 @@  __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
 
@@ -131,7 +131,7 @@  __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;