From 2c074b0d6cb2b28c5d1c0ccb2809965f4676efeb Mon Sep 17 00:00:00 2001 From: Rich Felker Date: Fri, 26 Apr 2013 19:48:01 -0400 Subject: [PATCH] transition to using functions for internal signal blocking/restoring there are several reasons for this change. one is getting rid of the repetition of the syscall signature all over the place. another is sharing the constant masks without costly GOT accesses in PIC. the main motivation, however, is accurately representing whether we want to block signals that might be handled by the application, or all signals. --- src/internal/pthread_impl.h | 4 ++++ src/signal/block.c | 44 +++++++++++++++++++++++++++++++++++++ src/signal/raise.c | 4 ++-- src/signal/siglongjmp.c | 4 ++-- src/thread/pthread_create.c | 13 +++++------ 5 files changed, 57 insertions(+), 12 deletions(-) create mode 100644 src/signal/block.c diff --git a/src/internal/pthread_impl.h b/src/internal/pthread_impl.h index 78b69cde..67b05753 100644 --- a/src/internal/pthread_impl.h +++ b/src/internal/pthread_impl.h @@ -115,6 +115,10 @@ void __acquire_ptc(); void __release_ptc(); void __inhibit_ptc(); +void __block_all_sigs(void *); +void __block_app_sigs(void *); +void __restore_sigs(void *); + #define DEFAULT_STACK_SIZE 81920 #define DEFAULT_GUARD_SIZE PAGE_SIZE diff --git a/src/signal/block.c b/src/signal/block.c new file mode 100644 index 00000000..d7f61001 --- /dev/null +++ b/src/signal/block.c @@ -0,0 +1,44 @@ +#include "pthread_impl.h" +#include "syscall.h" +#include + +static const unsigned long all_mask[] = { +#if ULONG_MAX == 0xffffffff && _NSIG == 129 + -1UL, -1UL, -1UL, -1UL +#elif ULONG_MAX == 0xffffffff + -1UL, -1UL +#else + -1UL +#endif +}; + +static const unsigned long app_mask[] = { +#if ULONG_MAX == 0xffffffff +#if _NSIG == 65 + 0x7fffffff, 0xfffffffc +#else + 0x7fffffff, 0xfffffffc, -1UL, -1UL +#endif +#else +#if _NSIG == 65 + 0xfffffffc7fffffff +#else + 0xfffffffc7fffffff, -1UL +#endif +#endif +}; + +void __block_all_sigs(void *set) +{ + __syscall(SYS_rt_sigprocmask, SIG_BLOCK, &all_mask, set, _NSIG/8); +} + +void __block_app_sigs(void *set) +{ + __syscall(SYS_rt_sigprocmask, SIG_BLOCK, &app_mask, set, _NSIG/8); +} + +void __restore_sigs(void *set) +{ + __syscall(SYS_rt_sigprocmask, SIG_SETMASK, set, 0, _NSIG/8); +} diff --git a/src/signal/raise.c b/src/signal/raise.c index b24dc741..6fa43bef 100644 --- a/src/signal/raise.c +++ b/src/signal/raise.c @@ -8,10 +8,10 @@ int raise(int sig) { int pid, tid, ret; sigset_t set; - __syscall(SYS_rt_sigprocmask, SIG_BLOCK, SIGALL_SET, &set, _NSIG/8); + __block_app_sigs(&set); tid = __syscall(SYS_gettid); pid = __syscall(SYS_getpid); ret = syscall(SYS_tgkill, pid, tid, sig); - __syscall(SYS_rt_sigprocmask, SIG_SETMASK, &set, 0, _NSIG/8); + __restore_sigs(&set); return ret; } diff --git a/src/signal/siglongjmp.c b/src/signal/siglongjmp.c index bbdde796..a7bcca24 100644 --- a/src/signal/siglongjmp.c +++ b/src/signal/siglongjmp.c @@ -2,10 +2,10 @@ #include #include #include "syscall.h" +#include "pthread_impl.h" _Noreturn void siglongjmp(sigjmp_buf buf, int ret) { - if (buf->__fl) __syscall(SYS_rt_sigprocmask, SIG_SETMASK, - buf->__ss, 0, _NSIG/8); + if (buf->__fl) __restore_sigs(buf->__ss); longjmp(buf->__jb, ret); } diff --git a/src/thread/pthread_create.c b/src/thread/pthread_create.c index 6e49acdc..6c841be7 100644 --- a/src/thread/pthread_create.c +++ b/src/thread/pthread_create.c @@ -35,7 +35,7 @@ _Noreturn void pthread_exit(void *result) * This is important to ensure that dynamically allocated TLS * is not under-allocated/over-committed, and possibly for other * reasons as well. */ - __syscall(SYS_rt_sigprocmask, SIG_BLOCK, SIGALL_SET, &set, _NSIG/8); + __block_all_sigs(&set); /* Wait to unlock the kill lock, which governs functions like * pthread_kill which target a thread id, until signals have @@ -51,7 +51,7 @@ _Noreturn void pthread_exit(void *result) * stdio cleanup code a consistent state. */ if (a_fetch_add(&libc.threads_minus_1, -1)==0) { libc.threads_minus_1 = 0; - __syscall(SYS_rt_sigprocmask, SIG_SETMASK, &set, 0, _NSIG/8); + __restore_sigs(&set); exit(0); } @@ -94,8 +94,7 @@ static int start(void *p) self->detached = 2; pthread_exit(0); } - __syscall(SYS_rt_sigprocmask, SIG_SETMASK, - self->sigmask, 0, _NSIG/8); + __restore_sigs(self->sigmask); } if (self->unblock_cancel) __syscall(SYS_rt_sigprocmask, SIG_UNBLOCK, @@ -202,8 +201,7 @@ int pthread_create(pthread_t *restrict res, const pthread_attr_t *restrict attrp } if (attr._a_sched) { do_sched = new->startlock[0] = 1; - __syscall(SYS_rt_sigprocmask, SIG_BLOCK, - SIGALL_SET, new->sigmask, _NSIG/8); + __block_app_sigs(new->sigmask); } new->unblock_cancel = self->cancel; new->canary = self->canary; @@ -214,8 +212,7 @@ int pthread_create(pthread_t *restrict res, const pthread_attr_t *restrict attrp __release_ptc(); if (do_sched) { - __syscall(SYS_rt_sigprocmask, SIG_SETMASK, - new->sigmask, 0, _NSIG/8); + __restore_sigs(new->sigmask); } if (ret < 0) { -- 2.25.1