Rich Felker
e74664016b
signals were wrongly left masked, and cancellability state was not switched to disabled, during the execution of cleanup handlers.
79 lines
1.8 KiB
C
79 lines
1.8 KiB
C
#include "pthread_impl.h"
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void __cancel()
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{
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pthread_t self = __pthread_self();
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self->canceldisable = 1;
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self->cancelasync = 0;
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pthread_exit(PTHREAD_CANCELED);
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}
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long __syscall_cp_asm(volatile void *, long, long, long, long, long, long, long);
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long (__syscall_cp)(long nr, long u, long v, long w, long x, long y, long z)
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{
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pthread_t self;
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uintptr_t old_sp, old_ip;
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long r;
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if (!libc.lock || (self = __pthread_self())->canceldisable)
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return __syscall(nr, u, v, w, x, y, z);
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old_sp = self->cp_sp;
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old_ip = self->cp_ip;
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self->cp_sp = 0;
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self->cp_ip = 0;
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r = __syscall_cp_asm(&self->cp_sp, nr, u, v, w, x, y, z);
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self->cp_sp = old_sp;
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self->cp_ip = old_ip;
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if (r == -EINTR && self->cancel) __cancel();
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return r;
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}
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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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uintptr_t sp = ((uintptr_t *)&uc->uc_mcontext)[CANCEL_REG_SP];
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uintptr_t ip = ((uintptr_t *)&uc->uc_mcontext)[CANCEL_REG_IP];
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if (!self->cancel || self->canceldisable) return;
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sigaddset(&uc->uc_sigmask, SIGCANCEL);
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if (self->cancelasync || sp == self->cp_sp && ip <= self->cp_ip) {
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self->canceldisable = 1;
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pthread_sigmask(SIG_SETMASK, &uc->uc_sigmask, 0);
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__cancel();
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}
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if (self->cp_sp)
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__syscall(SYS_tgkill, self->pid, self->tid, SIGCANCEL);
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}
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static 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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sigfillset(&sa.sa_mask);
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__libc_sigaction(SIGCANCEL, &sa, 0);
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libc.testcancel = testcancel;
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}
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int pthread_cancel(pthread_t t)
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{
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static pthread_once_t once;
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pthread_once(&once, init_cancellation);
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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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