diff mbox series

[2.31,3/5] support record failure: allow use from constructor

Message ID 20190807142726.2579-4-mathieu.desnoyers@efficios.com
State New
Headers show
Series Restartable Sequences support for glibc 2.31 | expand

Commit Message

Mathieu Desnoyers Aug. 7, 2019, 2:27 p.m. UTC 
Expose support_record_failure_init () so constructors can explicitly
initialize the record failure API.

This is preferred to lazy initialization at first use, because
lazy initialization does not cover use in constructors within
forked children processes (forked from parent constructor).

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
CC: Carlos O'Donell <carlos@redhat.com>
CC: Florian Weimer <fweimer@redhat.com>
CC: Joseph Myers <joseph@codesourcery.com>
CC: Szabolcs Nagy <szabolcs.nagy@arm.com>
CC: libc-alpha@sourceware.org
---
 support/check.h                  |  4 ++++
 support/support_record_failure.c | 18 +++++++++++++-----
 2 files changed, 17 insertions(+), 5 deletions(-)

Comments

Florian Weimer Oct. 16, 2019, 1:41 p.m. UTC | #1 
* Mathieu Desnoyers:

> diff --git a/support/support_record_failure.c b/support/support_record_failure.c
> index a8ffd1fb7d..86d9c71409 100644
> --- a/support/support_record_failure.c
> +++ b/support/support_record_failure.c
> @@ -32,8 +32,12 @@
>     zero, the failure of a test can be detected.
>  
>     The init constructor function below puts *state on a shared
> -   annonymous mapping, so that failure reports from subprocesses
> -   propagate to the parent process.  */
> +   anonymous mapping, so that failure reports from subprocesses
> +   propagate to the parent process.
> +
> +   support_record_failure_init is exposed so it can be called explicitly
> +   in case this API needs to be used from a constructor.  */
> +
>  struct test_failures
>  {
>    unsigned int counter;
> @@ -41,10 +45,14 @@ struct test_failures
>  };
>  static struct test_failures *state;
>  
> -static __attribute__ ((constructor)) void
> -init (void)
> +__attribute__ ((constructor)) void
> +support_record_failure_init (void)
>  {
> -  void *ptr = mmap (NULL, sizeof (*state), PROT_READ | PROT_WRITE,
> +  void *ptr;
> +
> +  if (state != NULL)
> +    return;
> +  ptr = mmap (NULL, sizeof (*state), PROT_READ | PROT_WRITE,
>                      MAP_ANONYMOUS | MAP_SHARED, -1, 0);
>    if (ptr == MAP_FAILED)
>      {

I think the general direction is useful here, but we should rather avoid
constructor ordering problems by using <allocate_once.h> here.  Let me
check how this would look like.

Thanks,
Florian
diff mbox series

Patch

diff --git a/support/check.h b/support/check.h
index eb3d2487a7..f8684a477a 100644
--- a/support/check.h
+++ b/support/check.h
@@ -88,6 +88,10 @@  void support_test_verify_exit_impl (int status, const char *file, int line,
    does not support reporting failures from a DSO.  */
 void support_record_failure (void);
 
+/* Initialize record failure.  Calling this is only needed when
+   recording failures from constructors.  */
+void support_record_failure_init (void);
+
 /* Static assertion, under a common name for both C++ and C11.  */
 #ifdef __cplusplus
 # define support_static_assert static_assert
diff --git a/support/support_record_failure.c b/support/support_record_failure.c
index a8ffd1fb7d..86d9c71409 100644
--- a/support/support_record_failure.c
+++ b/support/support_record_failure.c
@@ -32,8 +32,12 @@ 
    zero, the failure of a test can be detected.
 
    The init constructor function below puts *state on a shared
-   annonymous mapping, so that failure reports from subprocesses
-   propagate to the parent process.  */
+   anonymous mapping, so that failure reports from subprocesses
+   propagate to the parent process.
+
+   support_record_failure_init is exposed so it can be called explicitly
+   in case this API needs to be used from a constructor.  */
+
 struct test_failures
 {
   unsigned int counter;
@@ -41,10 +45,14 @@  struct test_failures
 };
 static struct test_failures *state;
 
-static __attribute__ ((constructor)) void
-init (void)
+__attribute__ ((constructor)) void
+support_record_failure_init (void)
 {
-  void *ptr = mmap (NULL, sizeof (*state), PROT_READ | PROT_WRITE,
+  void *ptr;
+
+  if (state != NULL)
+    return;
+  ptr = mmap (NULL, sizeof (*state), PROT_READ | PROT_WRITE,
                     MAP_ANONYMOUS | MAP_SHARED, -1, 0);
   if (ptr == MAP_FAILED)
     {