logd: add reinit command
- respond to SIGHUP
- respond to logd command "reinit"
- respond to logd --reinit
- reopens files on /data, eg: re-read of persistent properties
Bug: 19681572
Change-Id: Iadac58e6653f027cb7355497bd675eef376ce0a8
diff --git a/logd/main.cpp b/logd/main.cpp
index 243bee4..2d799bf 100644
--- a/logd/main.cpp
+++ b/logd/main.cpp
@@ -17,7 +17,10 @@
#include <dirent.h>
#include <errno.h>
#include <fcntl.h>
+#include <poll.h>
#include <sched.h>
+#include <semaphore.h>
+#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
@@ -30,6 +33,7 @@
#include <cutils/properties.h>
#include <cutils/sched_policy.h>
+#include <cutils/sockets.h>
#include "private/android_filesystem_config.h"
#include "CommandListener.h"
@@ -127,17 +131,100 @@
return def;
}
-// Foreground waits for exit of the three main persistent threads that
-// are started here. The three threads are created to manage UNIX
-// domain client sockets for writing, reading and controlling the user
-// space logger. Additional transitory per-client threads are created
-// for each reader once they register.
-int main() {
- bool auditd = property_get_bool("logd.auditd", true);
+static sem_t reinit;
+static bool reinit_running = false;
+static LogBuffer *logBuf = NULL;
- int fdDmesg = -1;
- if (auditd && property_get_bool("logd.auditd.dmesg", true)) {
- fdDmesg = open("/dev/kmsg", O_WRONLY);
+static void *reinit_thread_start(void * /*obj*/) {
+ prctl(PR_SET_NAME, "logd.daemon");
+ set_sched_policy(0, SP_BACKGROUND);
+
+ setgid(AID_LOGD);
+ setuid(AID_LOGD);
+
+ while (reinit_running && !sem_wait(&reinit) && reinit_running) {
+ // Anything that reads persist.<property>
+ if (logBuf) {
+ logBuf->init();
+ }
+ }
+
+ return NULL;
+}
+
+// Serves as a global method to trigger reinitialization
+// and as a function that can be provided to signal().
+void reinit_signal_handler(int /*signal*/) {
+ sem_post(&reinit);
+}
+
+// Remove the static, and use this variable
+// globally for debugging if necessary. eg:
+// write(fdDmesg, "I am here\n", 10);
+static int fdDmesg = -1;
+
+// Foreground waits for exit of the main persistent threads
+// that are started here. The threads are created to manage
+// UNIX domain client sockets for writing, reading and
+// controlling the user space logger, and for any additional
+// logging plugins like auditd and restart control. Additional
+// transitory per-client threads are created for each reader.
+int main(int argc, char *argv[]) {
+ 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(
+ socket_local_client("logd",
+ ANDROID_SOCKET_NAMESPACE_RESERVED,
+ SOCK_STREAM));
+ if (sock < 0) {
+ return -errno;
+ }
+ static const char reinit[] = "reinit";
+ ssize_t ret = TEMP_FAILURE_RETRY(write(sock, reinit, sizeof(reinit)));
+ if (ret < 0) {
+ return -errno;
+ }
+ struct pollfd p;
+ memset(&p, 0, sizeof(p));
+ p.fd = sock;
+ p.events = POLLIN;
+ ret = TEMP_FAILURE_RETRY(poll(&p, 1, 100));
+ if (ret < 0) {
+ return -errno;
+ }
+ if ((ret == 0) || !(p.revents & POLLIN)) {
+ return -ETIME;
+ }
+ static const char success[] = "success";
+ char buffer[sizeof(success) - 1];
+ memset(buffer, 0, sizeof(buffer));
+ ret = TEMP_FAILURE_RETRY(read(sock, buffer, sizeof(buffer)));
+ if (ret < 0) {
+ return -errno;
+ }
+ return strncmp(buffer, success, sizeof(success) - 1) != 0;
+ }
+
+ // Reinit Thread
+ sem_init(&reinit, 0, 0);
+ pthread_attr_t attr;
+ if (!pthread_attr_init(&attr)) {
+ struct sched_param param;
+
+ memset(¶m, 0, sizeof(param));
+ pthread_attr_setschedparam(&attr, ¶m);
+ pthread_attr_setschedpolicy(&attr, SCHED_BATCH);
+ if (!pthread_attr_setdetachstate(&attr,
+ PTHREAD_CREATE_DETACHED)) {
+ pthread_t thread;
+ reinit_running = true;
+ if (pthread_create(&thread, &attr, reinit_thread_start, NULL)) {
+ reinit_running = false;
+ }
+ }
+ pthread_attr_destroy(&attr);
}
if (drop_privs() != 0) {
@@ -153,7 +240,9 @@
// LogBuffer is the object which is responsible for holding all
// log entries.
- LogBuffer *logBuf = new LogBuffer(times);
+ logBuf = new LogBuffer(times);
+
+ signal(SIGHUP, reinit_signal_handler);
{
char property[PROPERTY_VALUE_MAX];
@@ -195,9 +284,13 @@
// initiated log messages. New log entries are added to LogBuffer
// and LogReader is notified to send updates to connected clients.
+ bool auditd = property_get_bool("logd.auditd", true);
+
if (auditd) {
+ bool dmesg = property_get_bool("logd.auditd.dmesg", true);
+
// failure is an option ... messages are in dmesg (required by standard)
- LogAudit *al = new LogAudit(logBuf, reader, fdDmesg);
+ LogAudit *al = new LogAudit(logBuf, reader, dmesg ? fdDmesg : -1);
int len = klogctl(KLOG_SIZE_BUFFER, NULL, 0);
if (len > 0) {
@@ -217,11 +310,10 @@
if (al->startListener()) {
delete al;
- close(fdDmesg);
}
}
- pause();
+ TEMP_FAILURE_RETRY(pause());
+
exit(0);
}
-