1#define _GNU_SOURCE 2#include <string.h> 3#include "pthread_impl.h" 4#include "syscall.h" 5#include "libc.h" 6 7__attribute__((__visibility__("hidden"))) 8long __cancel(), __syscall_cp_asm(), __syscall_cp_c(); 9 10long __cancel() 11{ 12 pthread_t self = __pthread_self(); 13 if (self->canceldisable == PTHREAD_CANCEL_ENABLE || self->cancelasync) 14 pthread_exit(PTHREAD_CANCELED); 15 self->canceldisable = PTHREAD_CANCEL_DISABLE; 16 return -ECANCELED; 17} 18 19long __syscall_cp_asm(volatile void *, syscall_arg_t, 20 syscall_arg_t, syscall_arg_t, syscall_arg_t, 21 syscall_arg_t, syscall_arg_t, syscall_arg_t); 22 23long __syscall_cp_c(syscall_arg_t nr, 24 syscall_arg_t u, syscall_arg_t v, syscall_arg_t w, 25 syscall_arg_t x, syscall_arg_t y, syscall_arg_t z) 26{ 27 pthread_t self; 28 long r; 29 int st; 30 31 if ((st=(self=__pthread_self())->canceldisable) 32 && (st==PTHREAD_CANCEL_DISABLE || nr==SYS_close)) 33 return __syscall(nr, u, v, w, x, y, z); 34 35 r = __syscall_cp_asm(&self->cancel, nr, u, v, w, x, y, z); 36 if (r==-EINTR && nr!=SYS_close && self->cancel && 37 self->canceldisable != PTHREAD_CANCEL_DISABLE) 38 r = __cancel(); 39 return r; 40} 41 42static void _sigaddset(sigset_t *set, int sig) 43{ 44 unsigned s = sig-1; 45 set->__bits[s/8/sizeof *set->__bits] |= 1UL<<(s&8*sizeof *set->__bits-1); 46} 47 48__attribute__((__visibility__("hidden"))) 49extern const char __cp_begin[1], __cp_end[1], __cp_cancel[1]; 50 51static void cancel_handler(int sig, siginfo_t *si, void *ctx) 52{ 53 pthread_t self = __pthread_self(); 54 ucontext_t *uc = ctx; 55 uintptr_t pc = uc->uc_mcontext.MC_PC; 56 57 a_barrier(); 58 if (!self->cancel || self->canceldisable == PTHREAD_CANCEL_DISABLE) return; 59 60 _sigaddset(&uc->uc_sigmask, SIGCANCEL); 61 62 if (self->cancelasync || pc >= (uintptr_t)__cp_begin && pc < (uintptr_t)__cp_end) { 63 uc->uc_mcontext.MC_PC = (uintptr_t)__cp_cancel; 64 return; 65 } 66 67 __syscall(SYS_tkill, self->tid, SIGCANCEL); 68} 69 70void __testcancel() 71{ 72 pthread_t self = __pthread_self(); 73 if (self->cancel && !self->canceldisable) 74 __cancel(); 75} 76 77static void init_cancellation() 78{ 79 struct sigaction sa = { 80 .sa_flags = SA_SIGINFO | SA_RESTART, 81 .sa_sigaction = cancel_handler 82 }; 83 memset(&sa.sa_mask, -1, _NSIG/8); 84 __libc_sigaction(SIGCANCEL, &sa, 0); 85} 86 87int pthread_cancel(pthread_t t) 88{ 89 static int init; 90 if (!init) { 91 init_cancellation(); 92 init = 1; 93 } 94 a_store(&t->cancel, 1); 95 if (t == pthread_self() && !t->cancelasync) return 0; 96 return pthread_kill(t, SIGCANCEL); 97} 98