nptl: Perform signal initialization upon pthread_create

Install signal handlers and unblock signals before pthread_create
creates the first thread.

create_thread in sysdeps/unix/sysv/linux/createthread.c can send
SIGCANCEL to the current thread, so the SIGCANCEL handler is currently
needed even if pthread_cancel is never called.  (The way timer_create
uses SIGCANCEL does not need a signal handler; both SIG_DFL and SIG_IGN
dispositions should work.)

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>

1 files changed, 6 insertions, 0 deletions

diff --git a/nptl/pthreadP.h b/nptl/pthreadP.h
index f93806e540..497c2ad3d9 100644
--- a/nptl/pthreadP.h
+++ b/nptl/pthreadP.h
@@ -571,6 +571,12 @@ libc_hidden_proto (__pthread_attr_setsigmask_internal)
 extern __typeof (pthread_attr_getsigmask_np) __pthread_attr_getsigmask_np;
 libc_hidden_proto (__pthread_attr_getsigmask_np)
 
+/* The cancellation signal handler defined alongside with
+   pthread_cancel.  This is included in statically linked binaries
+   only if pthread_cancel is linked in.  */
+void __nptl_sigcancel_handler (int sig, siginfo_t *si, void *ctx);
+libc_hidden_proto (__nptl_sigcancel_handler)
+
 /* Special versions which use non-exported functions.  */
 extern void __pthread_cleanup_push (struct _pthread_cleanup_buffer *buffer,
 				    void (*routine) (void *), void *arg);