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Commit 407537f7 authored by Mark Salyzyn's avatar Mark Salyzyn
Browse files

logd: add getEventTag id= command 

This is the precursor for "Plan B" recovery when access to
/dev/event-log-tags is blocked to untrusted zones.  Also
deals with mitigating issues with long-lived mappings that
do not update /dev/event-log-tags when dynamically changed.

Test: gTest logd-unit-test --gtest_filter=logd.getEventTag_42
Bug: 31456426
Bug: 35326290
Change-Id: I3db2e73763603727a369da3952c5ab4cf709f901
parent 8dcd94b2

logd/CommandListener.cpp

+16 −0
Original line number Diff line number Diff line
@@ -301,6 +301,7 @@ int CommandListener::GetEventTagCmd::runCommand(SocketClient *cli, 


    const char *name = NULL;

    const char *format = NULL;

    const char *id = NULL;

    for (int i = 1; i < argc; ++i) {

        static const char _name[] = "name=";

        if (!strncmp(argv[i], _name, strlen(_name))) {
@@ -313,6 +314,21 @@ int CommandListener::GetEventTagCmd::runCommand(SocketClient *cli, 
            format = argv[i] + strlen(_format);

            continue;

        }



        static const char _id[] = "id=";

        if (!strncmp(argv[i], _id, strlen(_id))) {

            id = argv[i] + strlen(_id);

            continue;

        }

    }



    if (id) {

        if (format || name) {

            cli->sendMsg("can not mix id= with either format= or name=");

            return 0;

        }

        cli->sendMsg(package_string(mBuf.formatEntry(atoi(id), uid)).c_str());

        return 0;

    }



    cli->sendMsg(package_string(mBuf.formatGetEventTag(uid,

logd/LogBuffer.h

+3 −0
Original line number Diff line number Diff line
@@ -140,6 +140,9 @@ public: 
                                  const char *name, const char *format) {

        return tags.formatGetEventTag(uid, name, format);

    }

    std::string formatEntry(uint32_t tag, uid_t uid) {

        return tags.formatEntry(tag, uid);

    }

    const char *tagToName(uint32_t tag) { return tags.tagToName(tag); }



    // helper must be protected directly or implicitly by lock()/unlock()

logd/LogTags.cpp

+5 −0
Original line number Diff line number Diff line
@@ -836,6 +836,11 @@ std::string LogTags::formatEntry_locked(uint32_t tag, uid_t uid, 
    return ret;

}



std::string LogTags::formatEntry(uint32_t tag, uid_t uid) {

    android::RWLock::AutoRLock readLock(rwlock);

    return formatEntry_locked(tag, uid);

}



std::string LogTags::formatGetEventTag(uid_t uid,

                                       const char* name, const char* format) {

    bool all = name && (name[0] == '*') && !name[1];

logd/LogTags.h

+1 −0
Original line number Diff line number Diff line
@@ -106,6 +106,7 @@ public: 
    // reverse lookup from tag

    const char* tagToName(uint32_t tag) const;

    const char* tagToFormat(uint32_t tag) const;

    std::string formatEntry(uint32_t tag, uid_t uid);

    // find associated tag

    uint32_t nameToTag(const char* name) const;

logd/tests/logd_test.cpp

+17 −0
Original line number Diff line number Diff line
@@ -836,6 +836,23 @@ TEST(logd, getEventTag_list) { 
#endif

}



TEST(logd, getEventTag_42) {

#ifdef __ANDROID__

    char buffer[256];

    memset(buffer, 0, sizeof(buffer));

    snprintf(buffer, sizeof(buffer), "getEventTag id=42");

    send_to_control(buffer, sizeof(buffer));

    buffer[sizeof(buffer) - 1] = '\0';

    char *cp;

    long ret = strtol(buffer, &cp, 10);

    EXPECT_GT(ret, 16);

    EXPECT_TRUE(strstr(buffer, "\t(to life the universe etc|3)") != NULL);

    EXPECT_TRUE(strstr(buffer, "answer") != NULL);

#else

    GTEST_LOG_(INFO) << "This test does nothing.\n";

#endif

}



TEST(logd, getEventTag_newentry) {

#ifdef __ANDROID__

    char buffer[256];