read and commented

kernel_liteos_a-master/testsuites/unittest/security/capability/smoke/cap_test_001.cpp

@@ -53,6 +53,7 @@ static void Child()
     while (i--) {
         sleep(1);
     }
+    //sleep for 10 second and exit; 
     exit(0);
 }
 
@@ -62,20 +63,22 @@ static int TestChild(VOID)
     struct __user_cap_data_struct capdata[CAP_NUM];
     struct __user_cap_data_struct capdatac[CAP_NUM];
     struct timespec tp;
-    int ret;
-
+    int ret
+    //originalize struct
     (void)memset_s(&capheader, sizeof(struct __user_cap_header_struct), 0, sizeof(struct __user_cap_header_struct));
     (void)memset_s(capdata, CAP_NUM * sizeof(struct __user_cap_data_struct), 0,
         CAP_NUM * sizeof(struct __user_cap_data_struct));
     capdata[0].permitted = 0xffffffff;
     capdata[1].permitted = 0xffffffff;
     capheader.version = _LINUX_CAPABILITY_VERSION_3;
+    //set capbility to effective
     capdata[CAP_TO_INDEX(CAP_SYS_NICE)].effective |= CAP_TO_MASK(CAP_SETPCAP);
     capdata[CAP_TO_INDEX(CAP_SYS_NICE)].effective |= CAP_TO_MASK(CAP_SETUID);
     capdata[CAP_TO_INDEX(CAP_SYS_NICE)].effective |= CAP_TO_MASK(CAP_KILL);
     capdata[CAP_TO_INDEX(CAP_SYS_NICE)].effective |= CAP_TO_MASK(CAP_SYS_TIME);
     capdata[CAP_TO_INDEX(CAP_SYS_NICE)].effective |= CAP_TO_MASK(CAP_SYS_NICE);
-    ret = capset(&capheader, &capdata[0]);
+    //use capset to check and get info
+	ret = capset(&capheader, &capdata[0]);
     ICUNIT_ASSERT_EQUAL(ret, 0, ret);
     ret = capget(&capheader, &capdatac[0]);
     ICUNIT_ASSERT_EQUAL(ret, 0, ret);
@@ -115,8 +118,8 @@ static int TestChild(VOID)
         printf("e %d,p %d\n", capdatac[0].effective, capdatac[0].permitted);
     }
     capheader.pid = 0;
-
-    int pid = fork();
+    //try reset UID
+    int pid = fork(); 
     if (pid == 0) {
         ret = setuid(CHANGE_CHILD_UID);
         ICUNIT_ASSERT_EQUAL(ret, 0, ret);
@@ -160,6 +163,7 @@ static int TestCase(VOID)
     int status = 0;
     pid_t pid = fork();
     ICUNIT_GOTO_WITHIN_EQUAL(pid, 0, 100000, pid, EXIT);
+    
     if (pid == 0) {
         ret = TestChild();
         exit(__LINE__);