Commit 24ef8601 authored Dec 20, 2016 by Adrian Salido

init/service.cpp: fix access check for console

Commit 9596d2b9 changes how
availability of console is checked by only checking access bits for
the console device. However, in cases where there is no console it
defaults to /dev/console. This device is always enumerated by tty
driver (i.e. file and access bits may be correct), but it doesn't
always map to an underlying console driver. Because the lookup for the
underlying console driver happens during the open system call, checking
only the access bits is not sufficient and need to make sure open
system call is successful, we can safely close the FD afterwards to
avoid FD leaks.

Test: boot device and check console svc doesn't continuously restart
Bug: 33691649
Change-Id: Ia51a8a2f56c345b70db55e95f61a057a98b52895

parent 8a1c4b85

init/service.cpp

+6 −3

Original line number	Diff line number	Diff line
		@@ -582,12 +582,15 @@ bool Service::Start() {
		console_ = default_console;
		}

		bool have_console = (access(console_.c_str(), R_OK \| W_OK) != -1);
		if (!have_console) {
		PLOG(ERROR) << "service '" << name_ << "' cannot gain read/write access to console '" << console_ << "'";
		// Make sure that open call succeeds to ensure a console driver is
		// properly registered for the device node
		int console_fd = open(console_.c_str(), O_RDWR \| O_CLOEXEC);
		if (console_fd < 0) {
		PLOG(ERROR) << "service '" << name_ << "' couldn't open console '" << console_ << "'";
		flags_ \|= SVC_DISABLED;
		return false;
		}
		close(console_fd);
		}

		struct stat sb;