diff options
Diffstat (limited to 'libpthread/linuxthreads/cancel.c')
| -rw-r--r-- | libpthread/linuxthreads/cancel.c | 238 |
1 files changed, 238 insertions, 0 deletions
diff --git a/libpthread/linuxthreads/cancel.c b/libpthread/linuxthreads/cancel.c new file mode 100644 index 000000000..27ec7f9c2 --- /dev/null +++ b/libpthread/linuxthreads/cancel.c @@ -0,0 +1,238 @@ +/* Linuxthreads - a simple clone()-based implementation of Posix */ +/* threads for Linux. */ +/* Copyright (C) 1996 Xavier Leroy (Xavier.Leroy@inria.fr) */ +/* */ +/* This program is free software; you can redistribute it and/or */ +/* modify it under the terms of the GNU Library General Public License */ +/* as published by the Free Software Foundation; either version 2 */ +/* of the License, or (at your option) any later version. */ +/* */ +/* This program 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 Library General Public License for more details. */ + +/* Thread cancellation */ + +#include <errno.h> +#include <libc-internal.h> +#include "pthread.h" +#include "internals.h" +#include "spinlock.h" +#include "restart.h" + +#ifdef _STACK_GROWS_DOWN +# define FRAME_LEFT(frame, other) ((char *) frame >= (char *) other) +#elif _STACK_GROWS_UP +# define FRAME_LEFT(frame, other) ((char *) frame <= (char *) other) +#else +# error "Define either _STACK_GROWS_DOWN or _STACK_GROWS_UP" +#endif + + +int __pthread_setcancelstate(int state, int * oldstate) +{ + pthread_descr self = thread_self(); + if (state < PTHREAD_CANCEL_ENABLE || state > PTHREAD_CANCEL_DISABLE) + return EINVAL; + if (oldstate != NULL) *oldstate = THREAD_GETMEM(self, p_cancelstate); + THREAD_SETMEM(self, p_cancelstate, state); + if (THREAD_GETMEM(self, p_canceled) && + THREAD_GETMEM(self, p_cancelstate) == PTHREAD_CANCEL_ENABLE && + THREAD_GETMEM(self, p_canceltype) == PTHREAD_CANCEL_ASYNCHRONOUS) + __pthread_do_exit(PTHREAD_CANCELED, CURRENT_STACK_FRAME); + return 0; +} +strong_alias (__pthread_setcancelstate, pthread_setcancelstate); + +int __pthread_setcanceltype(int type, int * oldtype) +{ + pthread_descr self = thread_self(); + if (type < PTHREAD_CANCEL_DEFERRED || type > PTHREAD_CANCEL_ASYNCHRONOUS) + return EINVAL; + if (oldtype != NULL) *oldtype = THREAD_GETMEM(self, p_canceltype); + THREAD_SETMEM(self, p_canceltype, type); + if (THREAD_GETMEM(self, p_canceled) && + THREAD_GETMEM(self, p_cancelstate) == PTHREAD_CANCEL_ENABLE && + THREAD_GETMEM(self, p_canceltype) == PTHREAD_CANCEL_ASYNCHRONOUS) + __pthread_do_exit(PTHREAD_CANCELED, CURRENT_STACK_FRAME); + return 0; +} +strong_alias (__pthread_setcanceltype, pthread_setcanceltype); + + +/* The next two functions are similar to pthread_setcanceltype() but + more specialized for the use in the cancelable functions like write(). + They do not need to check parameters etc. */ +int +attribute_hidden +__pthread_enable_asynccancel (void) +{ + pthread_descr self = thread_self(); + int oldtype = THREAD_GETMEM(self, p_canceltype); + THREAD_SETMEM(self, p_canceltype, PTHREAD_CANCEL_ASYNCHRONOUS); + if (__builtin_expect (THREAD_GETMEM(self, p_canceled), 0) && + THREAD_GETMEM(self, p_cancelstate) == PTHREAD_CANCEL_ENABLE) + __pthread_do_exit(PTHREAD_CANCELED, CURRENT_STACK_FRAME); + return oldtype; +} + +void +internal_function attribute_hidden +__pthread_disable_asynccancel (int oldtype) +{ + pthread_descr self = thread_self(); + THREAD_SETMEM(self, p_canceltype, oldtype); +} + + +int pthread_cancel(pthread_t thread) +{ + pthread_handle handle = thread_handle(thread); + int pid; + int dorestart = 0; + pthread_descr th; + pthread_extricate_if *pextricate; + int already_canceled; + + __pthread_lock(&handle->h_lock, NULL); + if (invalid_handle(handle, thread)) { + __pthread_unlock(&handle->h_lock); + return ESRCH; + } + + th = handle->h_descr; + + already_canceled = th->p_canceled; + th->p_canceled = 1; + + if (th->p_cancelstate == PTHREAD_CANCEL_DISABLE || already_canceled) { + __pthread_unlock(&handle->h_lock); + return 0; + } + + pextricate = th->p_extricate; + pid = th->p_pid; + + /* If the thread has registered an extrication interface, then + invoke the interface. If it returns 1, then we succeeded in + dequeuing the thread from whatever waiting object it was enqueued + with. In that case, it is our responsibility to wake it up. + And also to set the p_woken_by_cancel flag so the woken thread + can tell that it was woken by cancellation. */ + + if (pextricate != NULL) { + dorestart = pextricate->pu_extricate_func(pextricate->pu_object, th); + th->p_woken_by_cancel = dorestart; + } + + __pthread_unlock(&handle->h_lock); + + /* If the thread has suspended or is about to, then we unblock it by + issuing a restart, instead of a cancel signal. Otherwise we send + the cancel signal to unblock the thread from a cancellation point, + or to initiate asynchronous cancellation. The restart is needed so + we have proper accounting of restarts; suspend decrements the thread's + resume count, and restart() increments it. This also means that suspend's + handling of the cancel signal is obsolete. */ + + if (dorestart) + restart(th); + else + kill(pid, __pthread_sig_cancel); + + return 0; +} + +void pthread_testcancel(void) +{ + pthread_descr self = thread_self(); + if (THREAD_GETMEM(self, p_canceled) + && THREAD_GETMEM(self, p_cancelstate) == PTHREAD_CANCEL_ENABLE) + __pthread_do_exit(PTHREAD_CANCELED, CURRENT_STACK_FRAME); +} + +void _pthread_cleanup_push(struct _pthread_cleanup_buffer * buffer, + void (*routine)(void *), void * arg) +{ + pthread_descr self = thread_self(); + buffer->__routine = routine; + buffer->__arg = arg; + buffer->__prev = THREAD_GETMEM(self, p_cleanup); + if (buffer->__prev != NULL && FRAME_LEFT (buffer, buffer->__prev)) + buffer->__prev = NULL; + THREAD_SETMEM(self, p_cleanup, buffer); +} + +void _pthread_cleanup_pop(struct _pthread_cleanup_buffer * buffer, + int execute) +{ + pthread_descr self = thread_self(); + if (execute) buffer->__routine(buffer->__arg); + THREAD_SETMEM(self, p_cleanup, buffer->__prev); +} + +void _pthread_cleanup_push_defer(struct _pthread_cleanup_buffer * buffer, + void (*routine)(void *), void * arg) +{ + pthread_descr self = thread_self(); + buffer->__routine = routine; + buffer->__arg = arg; + buffer->__canceltype = THREAD_GETMEM(self, p_canceltype); + buffer->__prev = THREAD_GETMEM(self, p_cleanup); + if (buffer->__prev != NULL && FRAME_LEFT (buffer, buffer->__prev)) + buffer->__prev = NULL; + THREAD_SETMEM(self, p_canceltype, PTHREAD_CANCEL_DEFERRED); + THREAD_SETMEM(self, p_cleanup, buffer); +} + +void _pthread_cleanup_pop_restore(struct _pthread_cleanup_buffer * buffer, + int execute) +{ + pthread_descr self = thread_self(); + if (execute) buffer->__routine(buffer->__arg); + THREAD_SETMEM(self, p_cleanup, buffer->__prev); + THREAD_SETMEM(self, p_canceltype, buffer->__canceltype); + if (THREAD_GETMEM(self, p_canceled) && + THREAD_GETMEM(self, p_cancelstate) == PTHREAD_CANCEL_ENABLE && + THREAD_GETMEM(self, p_canceltype) == PTHREAD_CANCEL_ASYNCHRONOUS) + __pthread_do_exit(PTHREAD_CANCELED, CURRENT_STACK_FRAME); +} + +extern void __rpc_thread_destroy(void); +void __pthread_perform_cleanup(char *currentframe) +{ + pthread_descr self = thread_self(); + struct _pthread_cleanup_buffer *c = THREAD_GETMEM(self, p_cleanup); + struct _pthread_cleanup_buffer *last; + + if (c != NULL) + while (FRAME_LEFT (currentframe, c)) + { + last = c; + c = c->__prev; + + if (c == NULL || FRAME_LEFT (last, c)) + { + c = NULL; + break; + } + } + + while (c != NULL) + { + c->__routine(c->__arg); + + last = c; + c = c->__prev; + + if (FRAME_LEFT (last, c)) + break; + } + +#ifdef __UCLIBC_HAS_RPC__ + /* And the TSD which needs special help. */ + if (THREAD_GETMEM(self, p_libc_specific[_LIBC_TSD_KEY_RPC_VARS]) != NULL) + __rpc_thread_destroy (); +#endif +} |