logd: inherit android_get_control_file() (1259d9ea) · Commits · e / os / android_system_core

logd/logd.rc

+2 −0

Original line number	Diff line number	Diff line
		@@ -2,6 +2,8 @@ service logd /system/bin/logd
		socket logd stream 0666 logd logd
		socket logdr seqpacket 0666 logd logd
		socket logdw dgram 0222 logd logd
		file /proc/kmsg r
		file /dev/kmsg w
		group root system readproc
		writepid /dev/cpuset/system-background/tasks

logd/main.cpp

+28 −16

Original line number	Diff line number	Diff line
		@@ -39,6 +39,7 @@
		#include <android-base/macros.h>
		#include <cutils/properties.h>
		#include <cutils/sched_policy.h>
		#include <cutils/files.h>
		#include <cutils/sockets.h>
		#include <libminijail.h>
		#include <log/event_tag_map.h>
		@@ -189,11 +190,11 @@ static void reinit_thread_start(void /obj/) {
		set_sched_policy(0, SP_BACKGROUND);
		setpriority(PRIO_PROCESS, 0, ANDROID_PRIORITY_BACKGROUND);

		// If we are AID_ROOT, we should drop to AID_SYSTEM, if we are anything
		// else, we have even lesser privileges and accept our fate. Not worth
		// checking for error returns setting this thread's privileges.
		(void)setgid(AID_SYSTEM);
		(void)setuid(AID_SYSTEM);
		// If we are AID_ROOT, we should drop to AID_LOGD+AID_SYSTEM, if we are
		// anything else, we have even lesser privileges and accept our fate. Not
		// worth checking for error returns setting this thread's privileges.
		(void)setgid(AID_SYSTEM); // readonly access to /data/system/packages.list
		(void)setuid(AID_LOGD); // access to everything logd.

		while (reinit_running && !sem_wait(&reinit) && reinit_running) {

		@@ -318,17 +319,6 @@ static void readDmesg(LogAudit al, LogKlog kl) {
		// logging plugins like auditd and restart control. Additional
		// transitory per-client threads are created for each reader.
		int main(int argc, char *argv[]) {
		int fdPmesg = -1;
		bool klogd = __android_logger_property_get_bool("logd.kernel",
		BOOL_DEFAULT_TRUE \|
		BOOL_DEFAULT_FLAG_PERSIST \|
		BOOL_DEFAULT_FLAG_ENG \|
		BOOL_DEFAULT_FLAG_SVELTE);
		if (klogd) {
		fdPmesg = open("/proc/kmsg", O_RDONLY \| O_NDELAY);
		}
		fdDmesg = open("/dev/kmsg", O_WRONLY);

		// issue reinit command. KISS argument parsing.
		if ((argc > 1) && argv[1] && !strcmp(argv[1], "--reinit")) {
		int sock = TEMP_FAILURE_RETRY(
		@@ -364,6 +354,28 @@ int main(int argc, char *argv[]) {
		return strncmp(buffer, success, sizeof(success) - 1) != 0;
		}

		static const char dev_kmsg[] = "/dev/kmsg";
		fdDmesg = android_get_control_file(dev_kmsg);
		if (fdDmesg < 0) {
		fdDmesg = TEMP_FAILURE_RETRY(open(dev_kmsg, O_WRONLY \| O_CLOEXEC));
		}

		int fdPmesg = -1;
		bool klogd = __android_logger_property_get_bool("logd.kernel",
		BOOL_DEFAULT_TRUE \|
		BOOL_DEFAULT_FLAG_PERSIST \|
		BOOL_DEFAULT_FLAG_ENG \|
		BOOL_DEFAULT_FLAG_SVELTE);
		if (klogd) {
		static const char proc_kmsg[] = "/proc/kmsg";
		fdPmesg = android_get_control_file(proc_kmsg);
		if (fdPmesg < 0) {
		fdPmesg = TEMP_FAILURE_RETRY(open(proc_kmsg,
		O_RDONLY \| O_NDELAY \| O_CLOEXEC));
		}
		if (fdPmesg < 0) android::prdebug("Failed to open %s\n", proc_kmsg);
		}

		// Reinit Thread
		sem_init(&reinit, 0, 0);
		sem_init(&uidName, 0, 0);