Rich Felker
9c738dc183
applying the attribute to a weak_alias macro was a hack. instead use a separate declaration to apply the visibility, and consolidate declarations together to avoid having visibility mess all over the file.
106 lines
2.7 KiB
C
106 lines
2.7 KiB
C
#include <string.h>
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#include "pthread_impl.h"
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#include "syscall.h"
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#include "libc.h"
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#ifdef SHARED
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__attribute__((__visibility__("hidden")))
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#endif
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long __cancel(), __cp_cancel(), __syscall_cp_asm(), __syscall_cp_c();
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long __cancel()
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{
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pthread_t self = __pthread_self();
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if (self->canceldisable == PTHREAD_CANCEL_ENABLE || self->cancelasync)
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pthread_exit(PTHREAD_CANCELED);
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self->canceldisable = PTHREAD_CANCEL_DISABLE;
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return -ECANCELED;
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}
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/* If __syscall_cp_asm has adjusted the stack pointer, it must provide a
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* definition of __cp_cancel to undo those adjustments and call __cancel.
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* Otherwise, __cancel provides a definition for __cp_cancel. */
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weak_alias(__cancel, __cp_cancel);
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long __syscall_cp_asm(volatile void *, syscall_arg_t,
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syscall_arg_t, syscall_arg_t, syscall_arg_t,
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syscall_arg_t, syscall_arg_t, syscall_arg_t);
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long __syscall_cp_c(syscall_arg_t nr,
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syscall_arg_t u, syscall_arg_t v, syscall_arg_t w,
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syscall_arg_t x, syscall_arg_t y, syscall_arg_t z)
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{
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pthread_t self;
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long r;
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int st;
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if ((st=(self=__pthread_self())->canceldisable)
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&& (st==PTHREAD_CANCEL_DISABLE || nr==SYS_close))
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return __syscall(nr, u, v, w, x, y, z);
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r = __syscall_cp_asm(&self->cancel, nr, u, v, w, x, y, z);
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if (r==-EINTR && nr!=SYS_close && self->cancel &&
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self->canceldisable != PTHREAD_CANCEL_DISABLE)
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r = __cancel();
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return r;
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}
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static void _sigaddset(sigset_t *set, int sig)
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{
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unsigned s = sig-1;
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set->__bits[s/8/sizeof *set->__bits] |= 1UL<<(s&8*sizeof *set->__bits-1);
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}
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#ifdef SHARED
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__attribute__((__visibility__("hidden")))
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#endif
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extern const char __cp_begin[1], __cp_end[1];
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static void cancel_handler(int sig, siginfo_t *si, void *ctx)
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{
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pthread_t self = __pthread_self();
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ucontext_t *uc = ctx;
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const char *ip = ((char **)&uc->uc_mcontext)[CANCEL_REG_IP];
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a_barrier();
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if (!self->cancel || self->canceldisable == PTHREAD_CANCEL_DISABLE) return;
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_sigaddset(&uc->uc_sigmask, SIGCANCEL);
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if (self->cancelasync || ip >= __cp_begin && ip < __cp_end) {
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((char **)&uc->uc_mcontext)[CANCEL_REG_IP] = (char *)__cp_cancel;
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return;
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}
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__syscall(SYS_tkill, self->tid, SIGCANCEL);
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}
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void __testcancel()
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{
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pthread_t self = __pthread_self();
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if (self->cancel && !self->canceldisable)
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__cancel();
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}
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static void init_cancellation()
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{
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struct sigaction sa = {
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.sa_flags = SA_SIGINFO | SA_RESTART,
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.sa_sigaction = cancel_handler
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};
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memset(&sa.sa_mask, -1, _NSIG/8);
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__libc_sigaction(SIGCANCEL, &sa, 0);
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}
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int pthread_cancel(pthread_t t)
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{
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static int init;
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if (!init) {
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init_cancellation();
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init = 1;
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}
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a_store(&t->cancel, 1);
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return pthread_kill(t, SIGCANCEL);
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}
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