debuggerd_handler: restore errno.
Bug: http://b/31448909
Test: mma
Change-Id: I737d66e8bed5fb31c2558f68608d3df460fa73c9
diff --git a/debuggerd/handler/debuggerd_handler.cpp b/debuggerd/handler/debuggerd_handler.cpp
index c09c2f3..cf24d57 100644
--- a/debuggerd/handler/debuggerd_handler.cpp
+++ b/debuggerd/handler/debuggerd_handler.cpp
@@ -62,6 +62,19 @@
#define CRASH_DUMP_PATH "/system/bin/" CRASH_DUMP_NAME
+class ErrnoRestorer {
+ public:
+ ErrnoRestorer() : saved_errno_(errno) {
+ }
+
+ ~ErrnoRestorer() {
+ errno = saved_errno_;
+ }
+
+ private:
+ int saved_errno_;
+};
+
extern "C" void debuggerd_fallback_handler(siginfo_t*, ucontext_t*, void*);
static debuggerd_callbacks_t g_callbacks;
@@ -328,6 +341,10 @@
// Handler that does crash dumping by forking and doing the processing in the child.
// Do this by ptracing the relevant thread, and then execing debuggerd to do the actual dump.
static void debuggerd_signal_handler(int signal_number, siginfo_t* info, void* context) {
+ // Make sure we don't change the value of errno, in case a signal comes in between the process
+ // making a syscall and checking errno.
+ ErrnoRestorer restorer;
+
// It's possible somebody cleared the SA_SIGINFO flag, which would mean
// our "info" arg holds an undefined value.
if (!have_siginfo(signal_number)) {