From 370f78f2c80c64b7b0780a01e672494a26b5678e Mon Sep 17 00:00:00 2001 From: Rich Felker Date: Wed, 9 Mar 2011 19:42:06 -0500 Subject: fix raise semantics with threads. --- src/signal/raise.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) diff --git a/src/signal/raise.c b/src/signal/raise.c index 52f8b428..f437d23f 100644 --- a/src/signal/raise.c +++ b/src/signal/raise.c @@ -1,7 +1,18 @@ #include +#include #include "syscall.h" int raise(int sig) { - return __syscall_kill(__syscall_getpid(), sig); + int pid, tid, ret; + /* Getting the pid/tid pair is not atomic, and could give wrong + * result if a fork occurs in a signal handler between the two + * syscalls. Use the tgkill syscall's ESRCH semantics to detect + * this condition and retry. */ + do { + tid = syscall0(__NR_gettid); + pid = syscall0(__NR_getpid); + ret = syscall3(__NR_tgkill, pid, tid, sig); + } while (ret<0 && errno == ESRCH); + return ret; } -- cgit v1.2.1