logd: uidToName improvement
- read packages.list to acquire package names
- hijack the reinit handler as a privileged worker
Bug: 19608965
Change-Id: If7becb34354d6415e5c387ecea7d4109a15259c9
diff --git a/logd/main.cpp b/logd/main.cpp
index a61beff..1ffb8b0 100644
--- a/logd/main.cpp
+++ b/logd/main.cpp
@@ -143,6 +143,10 @@
// write(fdDmesg, "I am here\n", 10);
static int fdDmesg = -1;
+static sem_t uidName;
+static uid_t uid;
+static char *name;
+
static sem_t reinit;
static bool reinit_running = false;
static LogBuffer *logBuf = NULL;
@@ -151,10 +155,45 @@
prctl(PR_SET_NAME, "logd.daemon");
set_sched_policy(0, SP_BACKGROUND);
- setgid(AID_LOGD);
- setuid(AID_LOGD);
+ setgid(AID_SYSTEM);
+ setuid(AID_SYSTEM);
while (reinit_running && !sem_wait(&reinit) && reinit_running) {
+
+ // uidToName Privileged Worker
+ if (uid) {
+ name = NULL;
+
+ FILE *fp = fopen("/data/system/packages.list", "r");
+ if (fp) {
+ // This simple parser is sensitive to format changes in
+ // frameworks/base/services/core/java/com/android/server/pm/Settings.java
+ // A dependency note has been added to that file to correct
+ // this parser.
+
+ char *buffer = NULL;
+ size_t len;
+ while (getline(&buffer, &len, fp) > 0) {
+ char *userId = strchr(buffer, ' ');
+ if (!userId) {
+ continue;
+ }
+ *userId = '\0';
+ unsigned long value = strtoul(userId + 1, NULL, 10);
+ if (value != uid) {
+ continue;
+ }
+ name = strdup(buffer);
+ break;
+ }
+ free(buffer);
+ fclose(fp);
+ }
+ uid = 0;
+ sem_post(&uidName);
+ continue;
+ }
+
if (fdDmesg >= 0) {
static const char reinit_message[] = { KMSG_PRIORITY(LOG_INFO),
'l', 'o', 'g', 'd', '.', 'd', 'a', 'e', 'm', 'o', 'n', ':',
@@ -171,6 +210,20 @@
return NULL;
}
+char *android::uidToName(uid_t u) {
+ if (!u || !reinit_running) {
+ return NULL;
+ }
+
+ // Not multi-thread safe, we know there is only one caller
+ uid = u;
+
+ name = NULL;
+ sem_post(&reinit);
+ sem_wait(&uidName);
+ return name;
+}
+
// Serves as a global method to trigger reinitialization
// and as a function that can be provided to signal().
void reinit_signal_handler(int /*signal*/) {
@@ -223,6 +276,7 @@
// Reinit Thread
sem_init(&reinit, 0, 0);
+ sem_init(&uidName, 0, 0);
pthread_attr_t attr;
if (!pthread_attr_init(&attr)) {
struct sched_param param;