mirror of
https://github.com/fluencelabs/musl
synced 2025-06-27 05:32:06 +00:00
36e8b6a28b
previously, only archs that needed to do stack cleanup defined a __cp_cancel label for acting on cancellation in their syscall asm, and a default definition was provided by a weak alias to __cancel, the C function. this resulted in wrong codegen for arm on gcc versions affected by pr 68178 and possibly similar issues (like pr 66609) on other archs, and also created an inconsistency where the __cp_begin and __cp_end labels were treated as const data but __cp_cancel was treated as a function. this in turn caused incorrect code generation on archs where function pointers point to function descriptors rather than code (for now, only sh/fdpic).
101 lines
2.4 KiB
C
101 lines
2.4 KiB
C
#define _GNU_SOURCE
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#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(), __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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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], __cp_cancel[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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uintptr_t pc = uc->uc_mcontext.MC_PC;
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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 || pc >= (uintptr_t)__cp_begin && pc < (uintptr_t)__cp_end) {
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uc->uc_mcontext.MC_PC = (uintptr_t)__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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