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Commit 95108f18 authored by Mark Salyzyn's avatar Mark Salyzyn
Browse files

logd: improve details on chatty records 

(Cherry pick from commit 21fb7e0b)

- Report applications UID, TID/PID by name.
- change wording to have an accurate connotation
- drop privilege check since filtered upstream

Bug: 19608965
Bug: 20334069
Bug: 20370119
Change-Id: I2b1c26580b4c2de293874214ff5ae745546f3cca
parent 5a9d33ee

logd/LogBuffer.cpp

+1 −1
Original line number Diff line number Diff line
@@ -631,7 +631,7 @@ uint64_t LogBuffer::flushTo( 
        pthread_mutex_unlock(&mLogElementsLock);



        // range locking in LastLogTimes looks after us

        max = element->flushTo(reader);

        max = element->flushTo(reader, this);



        if (max == element->FLUSH_ERROR) {

            return max;

logd/LogBuffer.h

+1 −0
Original line number Diff line number Diff line
@@ -74,6 +74,7 @@ public: 
    // helper

    char *pidToName(pid_t pid) { return stats.pidToName(pid); }

    uid_t pidToUid(pid_t pid) { return stats.pidToUid(pid); }

    char *uidToName(uid_t uid) { return stats.uidToName(uid); }



private:

    void maybePrune(log_id_t id);

logd/LogBufferElement.cpp

+89 −15
Original line number Diff line number Diff line
@@ -14,7 +14,9 @@ 
 * limitations under the License.

 */



#include <ctype.h>

#include <endian.h>

#include <fcntl.h>

#include <stdio.h>

#include <string.h>

#include <time.h>
@@ -48,18 +50,88 @@ LogBufferElement::~LogBufferElement() { 
    delete [] mMsg;

}



// caller must own and free character string

static char *tidToName(pid_t tid) {

    char *retval = NULL;

    char buffer[256];

    snprintf(buffer, sizeof(buffer), "/proc/%u/comm", tid);

    int fd = open(buffer, O_RDONLY);

    if (fd >= 0) {

        ssize_t ret = read(fd, buffer, sizeof(buffer));

        if (ret >= (ssize_t)sizeof(buffer)) {

            ret = sizeof(buffer) - 1;

        }

        while ((ret > 0) && isspace(buffer[ret - 1])) {

            --ret;

        }

        if (ret > 0) {

            buffer[ret] = '\0';

            retval = strdup(buffer);

        }

        close(fd);

    }



    // if nothing for comm, check out cmdline

    char *name = android::pidToName(tid);

    if (!retval) {

        retval = name;

        name = NULL;

    }



    // check if comm is truncated, see if cmdline has full representation

    if (name) {

        // impossible for retval to be NULL if name not NULL

        size_t retval_len = strlen(retval);

        size_t name_len = strlen(name);

        // KISS: ToDo: Only checks prefix truncated, not suffix, or both

        if ((retval_len < name_len) && !strcmp(retval, name + name_len - retval_len)) {

            free(retval);

            retval = name;

        } else {

            free(name);

        }

    }

    return retval;

}



// assumption: mMsg == NULL

size_t LogBufferElement::populateDroppedMessage(char *&buffer, bool privileged) {

    static const char format_uid[] = "uid=%u dropped=%u";

    static const size_t unprivileged_offset = 7;

size_t LogBufferElement::populateDroppedMessage(char *&buffer,

        LogBuffer *parent) {

    static const char tag[] = "logd";

    static const char format_uid[] = "uid=%u%s too chatty%s, expire %u line%s";



    size_t len;

    if (privileged) {

        len = snprintf(NULL, 0, format_uid, mUid, mDropped);

    } else {

        len = snprintf(NULL, 0, format_uid + unprivileged_offset, mDropped);

    char *name = parent->uidToName(mUid);

    char *commName = tidToName(mTid);

    if (!commName && (mTid != mPid)) {

        commName = tidToName(mPid);

    }

    if (!commName) {

        commName = parent->pidToName(mPid);

    }

    if (name && commName && !strcmp(name, commName)) {

        free(commName);

        commName = NULL;

    }

    if (name) {

        char *p = NULL;

        asprintf(&p, "(%s)", name);

        if (p) {

            free(name);

            name = p;

        }

    }

    if (commName) {

        char *p = NULL;

        asprintf(&p, " comm=%s", commName);

        if (p) {

            free(commName);

            commName = p;

        }

    }

    // identical to below to calculate the buffer size required

    size_t len = snprintf(NULL, 0, format_uid, mUid, name ? name : "",

                          commName ? commName : "",

                          mDropped, (mDropped > 1) ? "s" : "");



    size_t hdrLen;

    if (mLogId == LOG_ID_EVENTS) {
@@ -70,6 +142,8 @@ size_t LogBufferElement::populateDroppedMessage(char *&buffer, bool privileged) 


    buffer = static_cast<char *>(calloc(1, hdrLen + len + 1));

    if (!buffer) {

        free(name);

        free(commName);

        return 0;

    }
@@ -86,16 +160,16 @@ size_t LogBufferElement::populateDroppedMessage(char *&buffer, bool privileged) 
        strcpy(buffer + 1, tag);

    }



    if (privileged) {

        snprintf(buffer + hdrLen, len + 1, format_uid, mUid, mDropped);

    } else {

        snprintf(buffer + hdrLen, len + 1, format_uid + unprivileged_offset, mDropped);

    }

    snprintf(buffer + hdrLen, len + 1, format_uid, mUid, name ? name : "",

             commName ? commName : "",

             mDropped, (mDropped > 1) ? "s" : "");

    free(name);

    free(commName);



    return retval;

}



uint64_t LogBufferElement::flushTo(SocketClient *reader) {

uint64_t LogBufferElement::flushTo(SocketClient *reader, LogBuffer *parent) {

    struct logger_entry_v3 entry;



    memset(&entry, 0, sizeof(struct logger_entry_v3));
@@ -114,7 +188,7 @@ uint64_t LogBufferElement::flushTo(SocketClient *reader) { 
    char *buffer = NULL;



    if (!mMsg) {

        entry.len = populateDroppedMessage(buffer, clientHasLogCredentials(reader));

        entry.len = populateDroppedMessage(buffer, parent);

        if (!entry.len) {

            return mSequence;

        }

logd/LogBufferElement.h

+8 −3
Original line number Diff line number Diff line
@@ -28,15 +28,19 @@ 
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);



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

char *pidToName(pid_t pid);



}



static inline bool worstUidEnabledForLogid(log_id_t id) {

    return (id != LOG_ID_CRASH) && (id != LOG_ID_EVENTS);

}



class LogBuffer;



class LogBufferElement {

    const log_id_t mLogId;

    const uid_t mUid;
@@ -52,7 +56,8 @@ class LogBufferElement { 
    static atomic_int_fast64_t sequence;



    // assumption: mMsg == NULL

    size_t populateDroppedMessage(char *&buffer, bool privileged);

    size_t populateDroppedMessage(char *&buffer,

                                  LogBuffer *parent);



public:

    LogBufferElement(log_id_t log_id, log_time realtime,
@@ -78,7 +83,7 @@ public: 
    log_time getRealTime(void) const { return mRealTime; }



    static const uint64_t FLUSH_ERROR;

    uint64_t flushTo(SocketClient *writer);

    uint64_t flushTo(SocketClient *writer, LogBuffer *parent);

};



#endif

logd/LogStatistics.cpp

+1 −1
Original line number Diff line number Diff line
@@ -39,7 +39,7 @@ LogStatistics::LogStatistics() 
namespace android {



// caller must own and free character string

static char *pidToName(pid_t pid) {

char *pidToName(pid_t pid) {

    char *retval = NULL;

    if (pid == 0) { // special case from auditd for kernel

        retval = strdup("logd.auditd");