From 99b8a25e941e54537bf39ca2f265c345f393f112 Mon Sep 17 00:00:00 2001 From: Rich Felker Date: Sat, 7 May 2011 23:23:58 -0400 Subject: overhaul implementation-internal signal protections 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. --- src/signal/raise.c | 8 +++----- src/signal/sigaction.c | 2 +- src/signal/sigaddset.c | 2 +- src/signal/sigdelset.c | 2 +- src/signal/sigemptyset.c | 3 ++- src/signal/sigfillset.c | 8 +++++++- src/signal/sigismember.c | 2 +- src/signal/sigprocmask.c | 20 ++------------------ 8 files changed, 18 insertions(+), 29 deletions(-) (limited to 'src/signal') diff --git a/src/signal/raise.c b/src/signal/raise.c index 9948f418..71e0505b 100644 --- a/src/signal/raise.c +++ b/src/signal/raise.c @@ -1,18 +1,16 @@ #include #include +#include #include "syscall.h" -int __sigprocmask(int, const sigset_t *, sigset_t *); - int raise(int sig) { int pid, tid, ret; sigset_t set; - sigfillset(&set); - __sigprocmask(SIG_BLOCK, &set, &set); + __syscall(SYS_rt_sigprocmask, SIG_BLOCK, (uint64_t[]){-1}, &set, 8); tid = syscall(SYS_gettid); pid = syscall(SYS_getpid); ret = syscall(SYS_tgkill, pid, tid, sig); - __sigprocmask(SIG_SETMASK, &set, 0); + __syscall(SYS_rt_sigprocmask, SIG_SETMASK, &set, 0, 8); return ret; } diff --git a/src/signal/sigaction.c b/src/signal/sigaction.c index 887bbc4f..18956c6b 100644 --- a/src/signal/sigaction.c +++ b/src/signal/sigaction.c @@ -35,7 +35,7 @@ int __libc_sigaction(int sig, const struct sigaction *sa, struct sigaction *old) int __sigaction(int sig, const struct sigaction *sa, struct sigaction *old) { - if (sig-SIGCANCEL < 3U) { + if (sig-32U < 3) { errno = EINVAL; return -1; } diff --git a/src/signal/sigaddset.c b/src/signal/sigaddset.c index 23e655db..d632c6fb 100644 --- a/src/signal/sigaddset.c +++ b/src/signal/sigaddset.c @@ -4,7 +4,7 @@ int sigaddset(sigset_t *set, int sig) { unsigned s = sig-1; - if (s >= 8*sizeof(sigset_t)) { + if (s >= 8*sizeof(sigset_t) || s-32U<3) { errno = EINVAL; return -1; } diff --git a/src/signal/sigdelset.c b/src/signal/sigdelset.c index 14042fb8..f8794ad6 100644 --- a/src/signal/sigdelset.c +++ b/src/signal/sigdelset.c @@ -4,7 +4,7 @@ int sigdelset(sigset_t *set, int sig) { unsigned s = sig-1; - if (s >= 8*sizeof(sigset_t)) { + if (s >= 8*sizeof(sigset_t) || s-32U<3) { errno = EINVAL; return -1; } diff --git a/src/signal/sigemptyset.c b/src/signal/sigemptyset.c index 91f77adf..ca9b8920 100644 --- a/src/signal/sigemptyset.c +++ b/src/signal/sigemptyset.c @@ -3,6 +3,7 @@ int sigemptyset(sigset_t *set) { - memset(set, 0, sizeof *set); + set->__bits[0] = 0; + if (sizeof(long)==4) set->__bits[1] = 0; return 0; } diff --git a/src/signal/sigfillset.c b/src/signal/sigfillset.c index fab50a52..6c84b9b7 100644 --- a/src/signal/sigfillset.c +++ b/src/signal/sigfillset.c @@ -1,8 +1,14 @@ #include #include +#include int sigfillset(sigset_t *set) { - memset(set, -1, sizeof *set); +#if ULONG_MAX == 0xffffffff + set->__bits[0] = 0x7ffffffful; + set->__bits[1] = 0xfffffffcul; +#else + set->__bits[0] = 0xfffffffc7ffffffful; +#endif return 0; } diff --git a/src/signal/sigismember.c b/src/signal/sigismember.c index afd29e52..d3de6efb 100644 --- a/src/signal/sigismember.c +++ b/src/signal/sigismember.c @@ -4,7 +4,7 @@ int sigismember(const sigset_t *set, int sig) { unsigned s = sig-1; - if (s >= 8*sizeof(sigset_t)) { + if (s >= 8*sizeof(sigset_t) || s-32U<3) { errno = EINVAL; return -1; } diff --git a/src/signal/sigprocmask.c b/src/signal/sigprocmask.c index a272c10d..3f003afb 100644 --- a/src/signal/sigprocmask.c +++ b/src/signal/sigprocmask.c @@ -4,27 +4,11 @@ #include "libc.h" #include "pthread_impl.h" -int __libc_sigprocmask(int how, const sigset_t *set, sigset_t *old) +int sigprocmask(int how, const sigset_t *set, sigset_t *old) { - return syscall(SYS_rt_sigprocmask, how, set, old, 8); -} - -int __sigprocmask(int how, const sigset_t *set, sigset_t *old) -{ - sigset_t tmp; if (how > 2U) { errno = EINVAL; return -1; } - /* Disallow blocking thread control signals */ - if (set && how != SIG_UNBLOCK) { - tmp = *set; - set = &tmp; - sigdelset(&tmp, SIGCANCEL); - sigdelset(&tmp, SIGSYSCALL); - sigdelset(&tmp, SIGTIMER); - } - return __libc_sigprocmask(how, set, old); + return syscall(SYS_rt_sigprocmask, how, set, old, 8); } - -weak_alias(__sigprocmask, sigprocmask); -- cgit v1.2.1