[hurd,commited 02/10] htl: Add support for libc cancellation points

[Samuel Thibault]

---
 htl/Makefile                      |  1 +
 htl/Versions                      |  2 ++
 htl/cancellation.c                | 45 +++++++++++++++++++++++++++++++
 htl/pt-testcancel.c               |  3 ++-
 sysdeps/htl/pthreadP.h            |  1 +
 sysdeps/mach/hurd/sysdep-cancel.h | 20 ++++++++++++--
 6 files changed, 69 insertions(+), 3 deletions(-)
 create mode 100644 htl/cancellation.c

diff --git a/htl/Makefile b/htl/Makefile
index b2dc797ee4..1b33748934 100644
--- a/htl/Makefile
+++ b/htl/Makefile
@@ -132,6 +132,7 @@ libpthread-routines := pt-attr pt-attr-destroy 
pt-attr-getdetachstate           \
                                                                            \
        shm-directory                                                       \
                                                                            \
+       cancellation                                                        \
        cthreads-compat                                                     \
        herrno                                                              \
        $(SYSDEPS)
diff --git a/htl/Versions b/htl/Versions
index 4f5f727753..1ec6f363d5 100644
--- a/htl/Versions
+++ b/htl/Versions
@@ -168,6 +168,8 @@ libpthread {
     __pthread_mutex_init;
     __pthread_mutex_destroy;
     __pthread_mutex_timedlock;
+    __pthread_enable_asynccancel;
+    __pthread_disable_asynccancel;
 
     _pthread_mutex_lock; _pthread_mutex_trylock; _pthread_mutex_unlock;
     _pthread_rwlock_destroy; _pthread_rwlock_init;
diff --git a/htl/cancellation.c b/htl/cancellation.c
new file mode 100644
index 0000000000..598f911d91
--- /dev/null
+++ b/htl/cancellation.c
@@ -0,0 +1,45 @@
+/* Set the cancel type during blocking calls.
+   Copyright (C) 2020 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 <pthread.h>
+#include <pthreadP.h>
+#include <pt-internal.h>
+
+int __pthread_enable_asynccancel (void)
+{
+  struct __pthread *p = _pthread_self ();
+  int oldtype;
+
+  __pthread_mutex_lock (&p->cancel_lock);
+  oldtype = p->cancel_type;
+  p->cancel_type = PTHREAD_CANCEL_ASYNCHRONOUS;
+  __pthread_mutex_unlock (&p->cancel_lock);
+
+  __pthread_testcancel ();
+
+  return oldtype;
+}
+
+void __pthread_disable_asynccancel (int oldtype)
+{
+  struct __pthread *p = _pthread_self ();
+
+  __pthread_mutex_lock (&p->cancel_lock);
+  p->cancel_type = oldtype;
+  __pthread_mutex_unlock (&p->cancel_lock);
+}
diff --git a/htl/pt-testcancel.c b/htl/pt-testcancel.c
index 1ec324b95f..37326280ee 100644
--- a/htl/pt-testcancel.c
+++ b/htl/pt-testcancel.c
@@ -22,7 +22,7 @@
 #include <pthreadP.h>
 
 void
-pthread_testcancel (void)
+__pthread_testcancel (void)
 {
   struct __pthread *p = _pthread_self ();
   int cancelled;
@@ -34,3 +34,4 @@ pthread_testcancel (void)
   if (cancelled)
     __pthread_exit (PTHREAD_CANCELED);
 }
+strong_alias (__pthread_testcancel, pthread_testcancel)
diff --git a/sysdeps/htl/pthreadP.h b/sysdeps/htl/pthreadP.h
index 7de96120a4..2bb4baa249 100644
--- a/sysdeps/htl/pthreadP.h
+++ b/sysdeps/htl/pthreadP.h
@@ -84,6 +84,7 @@ int __pthread_attr_setstacksize (pthread_attr_t *__attr, 
size_t __stacksize);
 int __pthread_attr_setstack (pthread_attr_t *__attr, void *__stackaddr,
                             size_t __stacksize);
 int __pthread_attr_getstack (const pthread_attr_t *, void **, size_t *);
+void __pthread_testcancel (void);
 
 #if IS_IN (libpthread)
 hidden_proto (__pthread_key_create)
diff --git a/sysdeps/mach/hurd/sysdep-cancel.h 
b/sysdeps/mach/hurd/sysdep-cancel.h
index f686a39024..669c17151a 100644
--- a/sysdeps/mach/hurd/sysdep-cancel.h
+++ b/sysdeps/mach/hurd/sysdep-cancel.h
@@ -1,8 +1,24 @@
 #include <sysdep.h>
 
+int __pthread_enable_asynccancel (void);
+void __pthread_disable_asynccancel (int oldtype);
+
+#pragma weak __pthread_enable_asynccancel
+#pragma weak __pthread_disable_asynccancel
+
 /* Always multi-thread (since there's at least the sig handler), but no
    handling enabled.  */
 #define SINGLE_THREAD_P (0)
 #define RTLD_SINGLE_THREAD_P (0)
-#define LIBC_CANCEL_ASYNC()    0 /* Just a dummy value.  */
-#define LIBC_CANCEL_RESET(val) ((void)(val)) /* Nothing, but evaluate it.  */
+
+#define LIBC_CANCEL_ASYNC() ({ \
+       int __cancel_oldtype = 0; \
+       if (__pthread_enable_asynccancel) \
+               __cancel_oldtype = __pthread_enable_asynccancel(); \
+       __cancel_oldtype; \
+})
+
+#define LIBC_CANCEL_RESET(val) do { \
+       if (__pthread_disable_asynccancel) \
+               __pthread_disable_asynccancel (val); \
+} while (0)
-- 
2.24.1