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nptl: Consolidate async cancel enable/disable implementation in libc 

Previously, the source file nptl/cancellation.c was compiled multiple
times, for libc, libpthread, librt.  This commit switches to a single
implementation, with new __pthread_enable_asynccancel@@GLIBC_PRIVATE,
__pthread_disable_asynccancel@@GLIBC_PRIVATE exports.

The almost-unused CANCEL_ASYNC and CANCEL_RESET macros are replaced
by LIBC_CANCEL_ASYNC and LIBC_CANCEL_ASYNC macros.  They call the
__pthread_* functions unconditionally now.  The macros are still
needed because shared code uses them; Hurd has different definitions.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
This commit is contained in:
Florian Weimer 2021-05-05 17:15:57 +02:00
parent 0197c1bc60
commit ce0b7961ae
14 changed files with 25 additions and 110 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
elf/Makefile
View File

@ -528,8 +528,10 @@ $(objpfx)dl-allobjs.os: $(all-rtld-routines:%=$(objpfx)%.os)
# discovery mechanism is not compatible with the libc implementation
# when compiled for libc.
rtld-stubbed-symbols = \
__libc_disable_asynccancel \
__libc_enable_asynccancel \
__GI___pthread_disable_asynccancel \
__GI___pthread_enable_asynccancel \
__pthread_disable_asynccancel \
__pthread_enable_asynccancel \
calloc \
free \
malloc \

4
manual/llio.texi
View File

@ -2534,13 +2534,13 @@ aiocb64}, since the LFS transparently replaces the old interface.
@c sigemptyset ok
@c sigaddset ok
@c setjmp ok
@c CANCEL_ASYNC -> pthread_enable_asynccancel ok
@c LIBC_CANCEL_ASYNC -> __pthread_enable_asynccancel ok
@c do_cancel ok
@c pthread_unwind ok
@c Unwind_ForcedUnwind or longjmp ok [@ascuheap @acsmem?]
@c lll_lock @asulock @aculock
@c lll_unlock @asulock @aculock
@c CANCEL_RESET -> pthread_disable_asynccancel ok
@c LIBC_CANCEL_RESET -> __pthread_disable_asynccancel ok
@c lll_futex_wait ok
@c ->start_routine ok -----
@c call_tls_dtors @asulock @ascuheap @aculock @acsmem

4
nptl/Makefile
View File

@ -30,6 +30,7 @@ extra-libs-others := $(extra-libs)
routines = \
alloca_cutoff \
cancellation \
cleanup_compat \
cleanup_defer_compat \
cleanup_routine \
@ -39,7 +40,6 @@ routines = \
elision-trylock \
elision-unlock \
futex-internal \
libc-cancellation \
libc-cleanup \
libc_multiple_threads \
libc_pthread_init \
@ -157,7 +157,6 @@ shared-only-routines = forward
static-only-routines = pthread_atfork
libpthread-routines = \
cancellation \
cleanup \
cleanup_defer \
events \
@ -239,7 +238,6 @@ CFLAGS-pthread_setcanceltype.c += -fexceptions -fasynchronous-unwind-tables
# These are internal functions which similar functionality as setcancelstate
# and setcanceltype.
CFLAGS-cancellation.c += -fasynchronous-unwind-tables
CFLAGS-libc-cancellation.c += -fasynchronous-unwind-tables
# Calling pthread_exit() must cause the registered cancel handlers to
# be executed. Therefore exceptions have to be thrown through this

2
nptl/Versions
View File

@ -281,6 +281,8 @@ libc {
__pthread_cleanup_push;
__pthread_cleanup_upto;
__pthread_current_priority;
__pthread_disable_asynccancel;
__pthread_enable_asynccancel;
__pthread_force_elision;
__pthread_getattr_default_np;
__pthread_keys;

4
nptl/cancellation.c
View File

@ -28,7 +28,6 @@
AS-safe, with the exception of the actual cancellation, because they
are called by wrappers around AS-safe functions like write().*/
int
attribute_hidden
__pthread_enable_asynccancel (void)
{
struct pthread *self = THREAD_SELF;
@ -60,11 +59,11 @@ __pthread_enable_asynccancel (void)
return oldval;
}
libc_hidden_def (__pthread_enable_asynccancel)
/* See the comment for __pthread_enable_asynccancel regarding
the AS-safety of this function. */
void
attribute_hidden
__pthread_disable_asynccancel (int oldtype)
{
/* If asynchronous cancellation was enabled before we do not have
@ -102,3 +101,4 @@ __pthread_disable_asynccancel (int oldtype)
newval = THREAD_GETMEM (self, cancelhandling);
}
}
libc_hidden_def (__pthread_disable_asynccancel)

24
nptl/libc-cancellation.c
View File

@ -1,24 +0,0 @@
/* Copyright (C) 2002-2021 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
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 "pthreadP.h"
#define __pthread_enable_asynccancel __libc_enable_asynccancel
#define __pthread_disable_asynccancel __libc_disable_asynccancel
#include <nptl/cancellation.c>

2
nptl/pthreadP.h
View File

@ -567,8 +567,6 @@ libc_hidden_proto (__pthread_exit)
extern int __pthread_join (pthread_t threadid, void **thread_return);
extern int __pthread_setcanceltype (int type, int *oldtype);
libc_hidden_proto (__pthread_setcanceltype)
extern int __pthread_enable_asynccancel (void) attribute_hidden;
extern void __pthread_disable_asynccancel (int oldtype) attribute_hidden;
extern void __pthread_testcancel (void);
libc_hidden_proto (__pthread_testcancel)
extern int __pthread_clockjoin_ex (pthread_t, void **, clockid_t,

4
nptl/pthread_create.c
View File

@ -353,7 +353,7 @@ START_THREAD_DEFN
have ownership (see CONCURRENCY NOTES above). */
if (__glibc_unlikely (pd->stopped_start))
{
int oldtype = CANCEL_ASYNC ();
int oldtype = LIBC_CANCEL_ASYNC ();
/* Get the lock the parent locked to force synchronization. */
lll_lock (pd->lock, LLL_PRIVATE);
@ -363,7 +363,7 @@ START_THREAD_DEFN
/* And give it up right away. */
lll_unlock (pd->lock, LLL_PRIVATE);
CANCEL_RESET (oldtype);
LIBC_CANCEL_RESET (oldtype);
}
LIBC_PROBE (pthread_start, 3, (pthread_t) pd, pd->start_routine, pd->arg);

1
rt/Makefile
View File

@ -59,7 +59,6 @@ include ../Rules
CFLAGS-aio_suspend.c += -fexceptions
CFLAGS-mq_timedreceive.c += -fexceptions -fasynchronous-unwind-tables
CFLAGS-mq_timedsend.c += -fexceptions -fasynchronous-unwind-tables
CFLAGS-librt-cancellation.c += -fasynchronous-unwind-tables
LDFLAGS-rt.so = -Wl,--enable-new-dtags,-z,nodelete

3
sysdeps/nptl/Makefile
View File

@ -21,8 +21,7 @@ libpthread-sysdep_routines += errno-loc
endif
ifeq ($(subdir),rt)
librt-sysdep_routines += timer_routines librt-cancellation
CFLAGS-librt-cancellation.c += -fexceptions -fasynchronous-unwind-tables
librt-sysdep_routines += timer_routines
tests += tst-mqueue8x
CFLAGS-tst-mqueue8x.c += -fexceptions

24
sysdeps/nptl/librt-cancellation.c
View File

@ -1,24 +0,0 @@
/* Copyright (C) 2002-2021 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
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 <nptl/pthreadP.h>
#define __pthread_enable_asynccancel __librt_enable_asynccancel
#define __pthread_disable_asynccancel __librt_disable_asynccancel
#include <nptl/cancellation.c>

8
sysdeps/nptl/lowlevellock-futex.h
View File

@ -121,18 +121,18 @@
/* Like lll_futex_wait, but acting as a cancellable entrypoint. */
# define lll_futex_wait_cancel(futexp, val, private) \
({ \
int __oldtype = CANCEL_ASYNC (); \
int __oldtype = LIBC_CANCEL_ASYNC (); \
long int __err = lll_futex_wait (futexp, val, LLL_SHARED); \
CANCEL_RESET (__oldtype); \
LIBC_CANCEL_RESET (__oldtype); \
__err; \
})
/* Like lll_futex_timed_wait, but acting as a cancellable entrypoint. */
# define lll_futex_timed_wait_cancel(futexp, val, timeout, private) \
({ \
int __oldtype = CANCEL_ASYNC (); \
int __oldtype = LIBC_CANCEL_ASYNC (); \
long int __err = lll_futex_timed_wait (futexp, val, timeout, private); \
CANCEL_RESET (__oldtype); \
LIBC_CANCEL_RESET (__oldtype); \
__err; \
})

5
sysdeps/unix/sysv/linux/socketcall.h
View File

@ -89,11 +89,6 @@
})
#if IS_IN (libc)
# define __pthread_enable_asynccancel __libc_enable_asynccancel
# define __pthread_disable_asynccancel __libc_disable_asynccancel
#endif
#define SOCKETCALL_CANCEL(name, args...) \
({ \
int oldtype = LIBC_CANCEL_ASYNC (); \

44
sysdeps/unix/sysv/linux/sysdep-cancel.h
View File

@ -24,44 +24,14 @@
#include <tls.h>
#include <errno.h>
/* The two functions are in libc.so and not exported. */
extern int __libc_enable_asynccancel (void) attribute_hidden;
extern void __libc_disable_asynccancel (int oldtype) attribute_hidden;
/* The two functions are in librt.so and not exported. */
extern int __librt_enable_asynccancel (void) attribute_hidden;
extern void __librt_disable_asynccancel (int oldtype) attribute_hidden;
/* The two functions are in libpthread.so and not exported. */
extern int __pthread_enable_asynccancel (void) attribute_hidden;
extern void __pthread_disable_asynccancel (int oldtype) attribute_hidden;
/* Set cancellation mode to asynchronous. */
#define CANCEL_ASYNC() \
__pthread_enable_asynccancel ()
extern int __pthread_enable_asynccancel (void);
libc_hidden_proto (__pthread_enable_asynccancel)
#define LIBC_CANCEL_ASYNC() __pthread_enable_asynccancel ()
/* Reset to previous cancellation mode. */
#define CANCEL_RESET(oldtype) \
__pthread_disable_asynccancel (oldtype)
#if IS_IN (libc)
/* Same as CANCEL_ASYNC, but for use in libc.so. */
# define LIBC_CANCEL_ASYNC() \
__libc_enable_asynccancel ()
/* Same as CANCEL_RESET, but for use in libc.so. */
# define LIBC_CANCEL_RESET(oldtype) \
__libc_disable_asynccancel (oldtype)
#elif IS_IN (libpthread)
# define LIBC_CANCEL_ASYNC() CANCEL_ASYNC ()
# define LIBC_CANCEL_RESET(val) CANCEL_RESET (val)
#elif IS_IN (librt)
# define LIBC_CANCEL_ASYNC() \
__librt_enable_asynccancel ()
# define LIBC_CANCEL_RESET(val) \
__librt_disable_asynccancel (val)
#else
# define LIBC_CANCEL_ASYNC() 0 /* Just a dummy value. */
# define LIBC_CANCEL_RESET(val) ((void)(val)) /* Nothing, but evaluate it. */
#endif
extern void __pthread_disable_asynccancel (int oldtype);
libc_hidden_proto (__pthread_disable_asynccancel)
#define LIBC_CANCEL_RESET(oldtype) __pthread_disable_asynccancel (oldtype)
#endif