support: Add signal support to support_capture_subprocess_check

Signal zero does not terminate a process, so it is safe to use negative
values for signal numbers.

Adjust libio/tst-vtables-common.c to use this new functionality,
instead of determining the termination status for a signal indirectly.

1 files changed, 9 insertions, 6 deletions

diff --git a/support/capture_subprocess.h b/support/capture_subprocess.h
index b0886ba1d1..4734b877ad 100644
--- a/support/capture_subprocess.h
+++ b/support/capture_subprocess.h
@@ -49,13 +49,16 @@ enum support_capture_allow
   sc_allow_stderr = 0x04,
 };
 
-/* Check that the subprocess exited with STATUS and that only the
-   allowed outputs happened.  ALLOWED is a combination of
-   support_capture_allow flags.  Report errors under the CONTEXT
-   message.  */
+/* Check that the subprocess exited and that only the allowed outputs
+   happened.  If STATUS_OR_SIGNAL is nonnegative, it is the expected
+   (decoded) exit status of the process, as returned by WEXITSTATUS.
+   If STATUS_OR_SIGNAL is negative, -STATUS_OR_SIGNAL is the expected
+   termination signal, as returned by WTERMSIG.  ALLOWED is a
+   combination of support_capture_allow flags.  Report errors under
+   the CONTEXT message.  */
 void support_capture_subprocess_check (struct support_capture_subprocess *,
-                                       const char *context, int status,
-                                       int allowed)
+                                       const char *context,
+                                       int status_or_signal, int allowed)
   __attribute__ ((nonnull (1, 2)));
 
 #endif /* SUPPORT_CAPTURE_SUBPROCESS_H */