[1/3] support: Add support_wait_for_thread_exit
Checks
Context |
Check |
Description |
dj/TryBot-apply_patch |
success
|
Patch applied to master at the time it was sent
|
Commit Message
---
support/support.h | 4 ++
support/support_wait_for_thread_exit.c | 67 ++++++++++++++++++++++++++
2 files changed, 71 insertions(+)
create mode 100644 support/support_wait_for_thread_exit.c
Comments
On 17/08/2021 10:50, Florian Weimer via Libc-alpha wrote:
> ---
> support/support.h | 4 ++
> support/support_wait_for_thread_exit.c | 67 ++++++++++++++++++++++++++
Missing the Makefile entry for support_wait_for_thread_exit
> 2 files changed, 71 insertions(+)
> create mode 100644 support/support_wait_for_thread_exit.c
>
> diff --git a/support/support.h b/support/support.h
> index 834dba9097..a5978b939a 100644
> --- a/support/support.h
> +++ b/support/support.h
> @@ -174,6 +174,10 @@ timer_t support_create_timer (uint64_t sec, long int nsec, bool repeat,
> /* Disable the timer TIMER. */
> void support_delete_timer (timer_t timer);
>
> +/* Wait until all threads except the current thread have exited (as
> + far as the kernel is concerned). */
> +void support_wait_for_thread_exit (void);
> +
> struct support_stack
> {
> void *stack;
Ok.
> diff --git a/support/support_wait_for_thread_exit.c b/support/support_wait_for_thread_exit.c
> new file mode 100644
> index 0000000000..808901f746
> --- /dev/null
> +++ b/support/support_wait_for_thread_exit.c
> @@ -0,0 +1,67 @@
> +/* Wait until all threads except the current thread has exited.
> + 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 <dirent.h>
> +#include <errno.h>
> +#include <string.h>
> +#include <support/check.h>
> +#include <support/support.h>
> +#include <unistd.h>
> +
> +void
> +support_wait_for_thread_exit (void)
> +{
> + DIR *proc_self_task = opendir ("/proc/self/task");
> + if (proc_self_task == NULL)
> + /* Use a large timeout because we cannot verify that the thread
> + has exited. */
> + usleep (5 * 1000 * 1000);
> + else
> + {
> + int count;
> +
> + wait_again:
> + count = 0;
> + rewinddir (proc_self_task);
> + while (true)
> + {
> + errno = 0;
> + struct dirent *e = readdir (proc_self_task);
> + if (e == NULL && errno != 0)
> + FAIL_EXIT1 ("readdir: %m");
> + if (e == NULL)
> + {
> + /* Only the main thread remains. Testing may continue. */
> + TEST_VERIFY (count >= 1);
> + closedir (proc_self_task);
> + return;
> + }
> +
> + if (strcmp (e->d_name, ".") == 0 || strcmp (e->d_name, "..") == 0)
> + continue;
> +
> + ++count;
> + if (count > 1)
> + {
> + /* Small timeout to give the thread a chance to exit. */
> + usleep (50 * 1000);
> + goto wait_again;
> + }
> + }
> + }
> +}
>
I am not very found of interfaces that poll kernel resources using timeouts,
but I don't think we have a better Linux interface to handle this.
* Adhemerval Zanella:
> On 17/08/2021 10:50, Florian Weimer via Libc-alpha wrote:
>> ---
>> support/support.h | 4 ++
>> support/support_wait_for_thread_exit.c | 67 ++++++++++++++++++++++++++
>
> Missing the Makefile entry for support_wait_for_thread_exit
Huh, right. I must have put that into one of the other patches. Will
reshuffle.
>> +void
>> +support_wait_for_thread_exit (void)
>> +{
>> + DIR *proc_self_task = opendir ("/proc/self/task");
>> + if (proc_self_task == NULL)
>> + /* Use a large timeout because we cannot verify that the thread
>> + has exited. */
>> + usleep (5 * 1000 * 1000);
>> + else
>> + {
>> + int count;
>> +
>> + wait_again:
>> + count = 0;
>> + rewinddir (proc_self_task);
>> + while (true)
>> + {
>> + errno = 0;
>> + struct dirent *e = readdir (proc_self_task);
>> + if (e == NULL && errno != 0)
>> + FAIL_EXIT1 ("readdir: %m");
>> + if (e == NULL)
>> + {
>> + /* Only the main thread remains. Testing may continue. */
>> + TEST_VERIFY (count >= 1);
>> + closedir (proc_self_task);
>> + return;
>> + }
>> +
>> + if (strcmp (e->d_name, ".") == 0 || strcmp (e->d_name, "..") == 0)
>> + continue;
>> +
>> + ++count;
>> + if (count > 1)
>> + {
>> + /* Small timeout to give the thread a chance to exit. */
>> + usleep (50 * 1000);
>> + goto wait_again;
>> + }
>> + }
>> + }
>> +}
>>
>
> I am not very found of interfaces that poll kernel resources using timeouts,
> but I don't think we have a better Linux interface to handle this.
I think we could use pidfd_open and poll once we have a wrapper for
pidfd_open. Not sure if it's possible to get a pollable descriptor via
/proc.
Thanks,
Florian
@@ -174,6 +174,10 @@ timer_t support_create_timer (uint64_t sec, long int nsec, bool repeat,
/* Disable the timer TIMER. */
void support_delete_timer (timer_t timer);
+/* Wait until all threads except the current thread have exited (as
+ far as the kernel is concerned). */
+void support_wait_for_thread_exit (void);
+
struct support_stack
{
void *stack;
new file mode 100644
@@ -0,0 +1,67 @@
+/* Wait until all threads except the current thread has exited.
+ 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 <dirent.h>
+#include <errno.h>
+#include <string.h>
+#include <support/check.h>
+#include <support/support.h>
+#include <unistd.h>
+
+void
+support_wait_for_thread_exit (void)
+{
+ DIR *proc_self_task = opendir ("/proc/self/task");
+ if (proc_self_task == NULL)
+ /* Use a large timeout because we cannot verify that the thread
+ has exited. */
+ usleep (5 * 1000 * 1000);
+ else
+ {
+ int count;
+
+ wait_again:
+ count = 0;
+ rewinddir (proc_self_task);
+ while (true)
+ {
+ errno = 0;
+ struct dirent *e = readdir (proc_self_task);
+ if (e == NULL && errno != 0)
+ FAIL_EXIT1 ("readdir: %m");
+ if (e == NULL)
+ {
+ /* Only the main thread remains. Testing may continue. */
+ TEST_VERIFY (count >= 1);
+ closedir (proc_self_task);
+ return;
+ }
+
+ if (strcmp (e->d_name, ".") == 0 || strcmp (e->d_name, "..") == 0)
+ continue;
+
+ ++count;
+ if (count > 1)
+ {
+ /* Small timeout to give the thread a chance to exit. */
+ usleep (50 * 1000);
+ goto wait_again;
+ }
+ }
+ }
+}