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Commit 8dfaa86b authored by qiwang's avatar qiwang Committed by Luca Stefani
Browse files

Don't clear the output array if it failed to open the proc status file 



According to the original documentation, the functions in Process.java
should return -1 when the process doesn't exist,this should be detected
by Process.readProcLine() when it fails to open the /proc/<pid>/status
file. Unfortunately readProcLine() zeroes-out the output array before
attempting to open the file, so the expected return value -1 is changed
to be 0  when the process doesn't exist. It's inconsistent with the
interface description definition, so correct it.

Test: try to use Process.getUidForPid(int pid) api to read a non-existent
process pid's uid, it will return -1 instead of 0.

Merged-In: Ic2ac7defea8b15dd65f907d04e168a1283a4f621
Change-Id: Ic2ac7defea8b15dd65f907d04e168a1283a4f621
Signed-off-by: default avatarqiwang <wangqi_a@xiaomi.com>
parent f449c504

core/jni/android_util_Process.cpp

+11 −5
Original line number Diff line number Diff line
@@ -644,6 +644,12 @@ static jlong android_os_Process_getTotalMemory(JNIEnv* env, jobject clazz) 
    return si.totalram;

}



/*

 * The outFields array is initialized to -1 to allow the caller to identify

 * when the status file (and therefore the process) they specified is invalid.

 * This array should not be overwritten or cleared before we know that the

 * status file can be read.

 */

void android_os_Process_readProcLines(JNIEnv* env, jobject clazz, jstring fileStr,

                                      jobjectArray reqFields, jlongArray outFields)

{
@@ -692,14 +698,14 @@ void android_os_Process_readProcLines(JNIEnv* env, jobject clazz, jstring fileSt 
        return;

    }



    int fd = open(file.string(), O_RDONLY | O_CLOEXEC);



    if (fd >= 0) {

        //ALOGI("Clearing %" PRId32 " sizes", count);

        for (i=0; i<count; i++) {

            sizesArray[i] = 0;

        }



    int fd = open(file.string(), O_RDONLY | O_CLOEXEC);



    if (fd >= 0) {

        const size_t BUFFER_SIZE = 4096;

        char* buffer = (char*)malloc(BUFFER_SIZE);

        int len = read(fd, buffer, BUFFER_SIZE-1);

core/tests/coretests/src/android/os/ProcessTest.java

+27 −4
Original line number Diff line number Diff line
@@ -17,13 +17,12 @@ 


package android.os;



import androidx.test.filters.MediumTest;



import junit.framework.TestCase;



public class ProcessTest extends TestCase {



    @MediumTest

    private static final int BAD_PID = 0;



    public void testProcessGetUidFromName() throws Exception {

        assertEquals(android.os.Process.SYSTEM_UID, Process.getUidForName("system"));

        assertEquals(Process.BLUETOOTH_UID, Process.getUidForName("bluetooth"));
@@ -35,7 +34,6 @@ public class ProcessTest extends TestCase { 
                Process.getUidForName("u3_a100"));

    }



    @MediumTest

    public void testProcessGetUidFromNameFailure() throws Exception {

        // Failure cases

        assertEquals(-1, Process.getUidForName("u2a_foo"));
@@ -47,4 +45,29 @@ public class ProcessTest extends TestCase { 
        assertEquals(-1, Process.getUidForName("u2jhsajhfkjhsafkhskafhkashfkjashfkjhaskjfdhakj3"));

    }



    /**

     * Tests getUidForPid() by ensuring that it returns the correct value when the process queried

     * doesn't exist.

     */

    public void testGetUidForPidInvalidPid() {

        assertEquals(-1, Process.getUidForPid(BAD_PID));

    }



    /**

     * Tests getParentPid() by ensuring that it returns the correct value when the process queried

     * doesn't exist.

     */

    public void testGetParentPidInvalidPid() {

        assertEquals(-1, Process.getParentPid(BAD_PID));

    }



    /**

     * Tests getThreadGroupLeader() by ensuring that it returns the correct value when the

     * thread queried doesn't exist.

     */

    public void testGetThreadGroupLeaderInvalidTid() {

        // This function takes a TID instead of a PID but BAD_PID should also be a bad TID.

        assertEquals(-1, Process.getThreadGroupLeader(BAD_PID));

    }



}