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Commit 08739ba7 authored by Mark Salyzyn's avatar Mark Salyzyn
Browse files

logd: uidToName improvement 

- read packages.list to acquire package names
- hijack the reinit handler as a privileged worker

Bug: 19608965
Change-Id: If7becb34354d6415e5c387ecea7d4109a15259c9
parent 720f6d1d

logd/LogBufferElement.h

+8 −0
Original line number Diff line number Diff line
@@ -24,6 +24,14 @@ 
#include <log/log.h>

#include <log/log_read.h>



namespace android {



// Furnished in main.cpp. Caller must own and free returned value

// This function is designed for a single caller and is NOT thread-safe

char *uidToName(uid_t uid);



}



class LogBufferElement {

    const log_id_t mLogId;

    const uid_t mUid;

logd/LogStatistics.cpp

+5 −1
Original line number Diff line number Diff line
@@ -161,7 +161,11 @@ char *LogStatistics::uidToName(uid_t uid) { 
        ++info;

    }



    char *name = NULL;

    // Parse /data/system/packages.list

    char *name = android::uidToName(uid);

    if (name) {

        return name;

    }



    // report uid -> pid(s) -> pidToName if unique

    ssize_t index = -1;

logd/main.cpp

+56 −2
Original line number Diff line number Diff line
@@ -143,6 +143,10 @@ static bool property_get_bool(const char *key, bool def) { 
//   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 @@ 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);

    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 @@ static void *reinit_thread_start(void * /*obj*/) { 
    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 @@ int main(int argc, char *argv[]) { 


    // 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;