support empty string for value

Signed-off-by: Ncheng_jinsong <chengjinsong2@huawei.com>

services/param/linux/param_message.c

@@ -44,7 +44,7 @@ int ConnectServer(int fd, const char *servername)
 int FillParamMsgContent(const ParamMessage *request, uint32_t *start, int type, const char *value, uint32_t length)
 {
     PARAM_CHECK(request != NULL && start != NULL, return -1, "Invalid param");
-    PARAM_CHECK(value != NULL && length != 0, return -1, "Invalid value");
+    PARAM_CHECK(value != NULL, return -1, "Invalid value");
     uint32_t bufferSize = request->msgSize - sizeof(ParamMessage);
     uint32_t offset = *start;
     PARAM_CHECK((offset + sizeof(ParamMsgContent) + length) <= bufferSize,
@@ -52,8 +52,10 @@ int FillParamMsgContent(const ParamMessage *request, uint32_t *start, int type,
     ParamMsgContent *content = (ParamMsgContent *)(request->data + offset);
     content->type = type;
     content->contentSize = length + 1;
-    int ret = memcpy_s(content->content, content->contentSize - 1, value, length);
-    PARAM_CHECK(ret == EOK, return -1, "Failed to copy value for %d", type);
+    if (length > 0) {
+        int ret = memcpy_s(content->content, content->contentSize - 1, value, length);
+        PARAM_CHECK(ret == EOK, return -1, "Failed to copy value for %d", type);
+    }
     content->content[length] = '\0';
     offset += sizeof(ParamMsgContent) + PARAM_ALIGN(content->contentSize);
     *start = offset;

test/unittest/param/client_unittest.cpp

@@ -204,6 +204,18 @@ HWTEST_F(ClientUnitTest, TestClient_01, TestSize.Level0)
     SystemWaitParameter("@@@@", value.c_str(), 1);
 }
 
+HWTEST_F(ClientUnitTest, TestParamValue, TestSize.Level0)
+{
+    // support empty string
+    const char *name = "test_readonly.dddddddddddddddddd.fffffffffffffffffff";
+    int ret = SystemSetParameter(name, "");
+    EXPECT_EQ(ret, 0);
+    ret = SystemSetParameter(name, "111111111");
+    EXPECT_EQ(ret, 0);
+    ret = SystemSetParameter(name, "");
+    EXPECT_EQ(ret, 0);
+}
+
 HWTEST_F(ClientUnitTest, TestClient_02, TestSize.Level0)
 {
     char testBuffer[PARAM_BUFFER_SIZE] = {0};

test/unittest/param/param_unittest.cpp

@@ -40,7 +40,7 @@ static int CheckServerParamValue(const char *name, const char *expectValue)
     u_int32_t len = sizeof(tmp);
     SystemReadParam(name, tmp, &len);
     printf("CheckParamValue name %s value: \'%s\' expectValue:\'%s\' \n", name, tmp, expectValue);
-    EXPECT_NE((int)strlen(tmp), 0);
+    EXPECT_GE((int)strlen(tmp), 0);
     if (expectValue != nullptr) {
         EXPECT_EQ(strcmp(tmp, expectValue), 0);
     }
@@ -366,6 +366,21 @@ HWTEST_F(ParamUnitTest, TestNameIsValid, TestSize.Level0)
     test.TestNameIsValid();
 }
 
+HWTEST_F(ParamUnitTest, TestParamValue, TestSize.Level0)
+{
+    // support empty string
+    const char *name = "test_readonly.dddddddddddddddddd.fffffffffffffffffff";
+    int ret = SystemWriteParam(name, "");
+    EXPECT_EQ(ret, 0);
+    CheckServerParamValue(name, "");
+    ret = SystemWriteParam(name, "111111111");
+    EXPECT_EQ(ret, 0);
+    CheckServerParamValue(name, "111111111");
+    ret = SystemWriteParam(name, "");
+    EXPECT_EQ(ret, 0);
+    CheckServerParamValue(name, "");
+}
+
 HWTEST_F(ParamUnitTest, TestAddSecurityLabel1, TestSize.Level0)
 {
     ParamUnitTest test;
@@ -570,7 +585,7 @@ HWTEST_F(ParamUnitTest, TestRequestMessage, TestSize.Level0)
     ret = FillParamMsgContent(msg, &start, 0, nullptr, 0);
     EXPECT_NE(ret, 0);
     ret = FillParamMsgContent(msg, &start, 0, "22222", 0);
-    EXPECT_NE(ret, 0);
+    EXPECT_EQ(ret, 0);
     ret = FillParamMsgContent(msg, &start, 0, "22222", msgSize);
     EXPECT_NE(ret, 0);
     // fill success
@@ -587,7 +602,7 @@ HWTEST_F(ParamUnitTest, TestRequestMessage, TestSize.Level0)
     content = GetNextContent(msg, &offset);
     EXPECT_NE(content, nullptr);
     content = GetNextContent(msg, &offset);
-    EXPECT_EQ(content, nullptr);
+    EXPECT_NE(content, nullptr);
     free(msg);
 }