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authorTimothy E Baldwin <T.E.Baldwin99@members.leeds.ac.uk>2016-05-27 15:18:39 +0100
committerPeter Maydell <peter.maydell@linaro.org>2016-05-27 15:18:39 +0100
commitac42af98f74d6502e8ab3f8f7e014f3a1580e323 (patch)
treea52102eafff7106fe1ae6e8e85750f8566f81cde
parent3fbc3d58a2a05e54ef3d10ab990e35a226056002 (diff)
downloadqemu-arm-ac42af98f74d6502e8ab3f8f7e014f3a1580e323.tar.gz
linux-user: Block signals during sigaction() handling
Block signals while emulating sigaction. This is a non-interruptible syscall, and using block_signals() avoids races where the host signal handler is invoked and tries to examine the signal handler data structures while we are updating them. Signed-off-by: Timothy Edward Baldwin <T.E.Baldwin99@members.leeds.ac.uk> Message-id: 1441497448-32489-29-git-send-email-T.E.Baldwin99@members.leeds.ac.uk [PMM: expanded commit message] Reviewed-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
-rw-r--r--linux-user/signal.c12
1 files changed, 9 insertions, 3 deletions
diff --git a/linux-user/signal.c b/linux-user/signal.c
index f48902882d..b21d6bf625 100644
--- a/linux-user/signal.c
+++ b/linux-user/signal.c
@@ -640,7 +640,7 @@ out:
return ret;
}
-/* do_sigaction() return host values and errnos */
+/* do_sigaction() return target values and host errnos */
int do_sigaction(int sig, const struct target_sigaction *act,
struct target_sigaction *oact)
{
@@ -649,8 +649,14 @@ int do_sigaction(int sig, const struct target_sigaction *act,
int host_sig;
int ret = 0;
- if (sig < 1 || sig > TARGET_NSIG || sig == TARGET_SIGKILL || sig == TARGET_SIGSTOP)
- return -EINVAL;
+ if (sig < 1 || sig > TARGET_NSIG || sig == TARGET_SIGKILL || sig == TARGET_SIGSTOP) {
+ return -TARGET_EINVAL;
+ }
+
+ if (block_signals()) {
+ return -TARGET_ERESTARTSYS;
+ }
+
k = &sigact_table[sig - 1];
if (oact) {
__put_user(k->_sa_handler, &oact->_sa_handler);