mirror of
https://github.com/fluencelabs/musl
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99b8a25e94
the new approach relies on the fact that the only ways to create sigset_t objects without invoking UB are to use the sig*set() functions, or from the masks returned by sigprocmask, sigaction, etc. or in the ucontext_t argument to a signal handler. thus, as long as sigfillset and sigaddset avoid adding the "protected" signals, there is no way the application will ever obtain a sigset_t including these bits, and thus no need to add the overhead of checking/clearing them when sigprocmask or sigaction is called. note that the old code actually *failed* to remove the bits from sa_mask when sigaction was called. the new implementations are also significantly smaller, simpler, and faster due to ignoring the useless "GNU HURD signals" 65-1024, which are not used and, if there's any sanity in the world, never will be used.
46 lines
992 B
C
46 lines
992 B
C
#include <stdlib.h>
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#include <signal.h>
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#include <errno.h>
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#include "syscall.h"
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#include "pthread_impl.h"
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void __restore(), __restore_rt();
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int __libc_sigaction(int sig, const struct sigaction *sa, struct sigaction *old)
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{
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struct {
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void *handler;
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unsigned long flags;
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void (*restorer)(void);
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sigset_t mask;
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} ksa, kold;
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long pksa=0, pkold=0;
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if (sa) {
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ksa.handler = sa->sa_handler;
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ksa.flags = sa->sa_flags | SA_RESTORER;
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ksa.restorer = (sa->sa_flags & SA_SIGINFO) ? __restore_rt : __restore;
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ksa.mask = sa->sa_mask;
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pksa = (long)&ksa;
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}
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if (old) pkold = (long)&kold;
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if (syscall(SYS_rt_sigaction, sig, pksa, pkold, 8))
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return -1;
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if (old) {
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old->sa_handler = kold.handler;
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old->sa_flags = kold.flags;
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old->sa_mask = kold.mask;
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}
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return 0;
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}
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int __sigaction(int sig, const struct sigaction *sa, struct sigaction *old)
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{
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if (sig-32U < 3) {
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errno = EINVAL;
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return -1;
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}
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return __libc_sigaction(sig, sa, old);
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}
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weak_alias(__sigaction, sigaction);
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