Merge "incidentd: fix race in waitpid_with_timeout" into tm-dev (83a91c85) · Commits · e / os / android_frameworks_base

cmds/incidentd/src/incidentd_util.cpp

+27 −12

Original line number	Diff line number	Diff line
		@@ -184,11 +184,26 @@ static bool waitpid_with_timeout(pid_t pid, int timeout_ms, int* status) {
		sigemptyset(&child_mask);
		sigaddset(&child_mask, SIGCHLD);

		// block SIGCHLD before we check if a process has exited
		if (sigprocmask(SIG_BLOCK, &child_mask, &old_mask) == -1) {
		ALOGW("sigprocmask failed: %s", strerror(errno));
		ALOGW("*** sigprocmask failed: %s\n", strerror(errno));
		return false;
		}

		// if the child has exited already, handle and reset signals before leaving
		pid_t child_pid = waitpid(pid, status, WNOHANG);
		if (child_pid != pid) {
		if (child_pid > 0) {
		ALOGW("*** Waiting for pid %d, got pid %d instead\n", pid, child_pid);
		sigprocmask(SIG_SETMASK, &old_mask, nullptr);
		return false;
		}
		} else {
		sigprocmask(SIG_SETMASK, &old_mask, nullptr);
		return true;
		}

		// wait for a SIGCHLD
		timespec ts;
		ts.tv_sec = timeout_ms / 1000;
		ts.tv_nsec = (timeout_ms % 1000) * 1000000;
		@@ -197,7 +212,7 @@ static bool waitpid_with_timeout(pid_t pid, int timeout_ms, int* status) {

		// Set the signals back the way they were.
		if (sigprocmask(SIG_SETMASK, &old_mask, nullptr) == -1) {
		ALOGW("sigprocmask failed: %s", strerror(errno));
		ALOGW("*** sigprocmask failed: %s\n", strerror(errno));
		if (ret == 0) {
		return false;
		}
		@@ -207,22 +222,22 @@ static bool waitpid_with_timeout(pid_t pid, int timeout_ms, int* status) {
		if (errno == EAGAIN) {
		errno = ETIMEDOUT;
		} else {
		ALOGW("sigtimedwait failed: %s", strerror(errno));
		ALOGW("*** sigtimedwait failed: %s\n", strerror(errno));
		}
		return false;
		}

		pid_t child_pid = waitpid(pid, status, WNOHANG);
		if (child_pid == pid) {
		return true;
		}
		if (child_pid == -1) {
		ALOGW("waitpid failed: %s", strerror(errno));
		child_pid = waitpid(pid, status, WNOHANG);
		if (child_pid != pid) {
		if (child_pid != -1) {
		ALOGW("*** Waiting for pid %d, got pid %d instead\n", pid, child_pid);
		} else {
		ALOGW("Waiting for pid %d, got pid %d instead", pid, child_pid);
		ALOGW("*** waitpid failed: %s\n", strerror(errno));
		}
		return false;
		}
		return true;
		}

		status_t kill_child(pid_t pid) {
		int status;