Fix #1944, use 0 as the invalid CFE_SB_MsgId_t value

Historically the CFE_SB_MSG_ID_INVALID constant was defined as 0xFFFFFFFF/-1,
where 0 was considered valid.

Although 0 is indeed valid for the first word of a CCSDS primary spacepacket header,
it is not actually valid for use with SB.  Because SB is now more decoupled from CCSDS
header definitions, there are a number of advantages to using 0 instead of -1, as
it is more passively safe:

- Objects which are cleared as part of normal BSS clearing will be set invalid
- Objects which are memset to zero will be set invalid

In contrast, when the invalid value is nonzero, objects which are memset/cleared
are valid by default, and must be actively set invalid to be safe.

modules/cfe_testcase/src/msg_api_test.c

@@ -50,7 +50,7 @@ void TestMsgApiBasic(void)
     bool                    _returned = false;
 
     memset(&cmd, 0xFF, sizeof(cmd));
-    msgId = CFE_SB_ValueToMsgId(0);
+    msgId = CFE_SB_ValueToMsgId(1);
 
     /* test msg-init */
     UtAssert_INT32_EQ(CFE_MSG_Init(NULL, msgId, sizeof(cmd)), CFE_MSG_BAD_ARGUMENT);

modules/core_api/fsw/inc/cfe_sb_api_typedefs.h

@@ -96,7 +96,7 @@
  * This rvalue macro can be used for static/compile-time data initialization to ensure that
  * the initialized value does not alias to a valid MsgId object.
  */
-#define CFE_SB_MSGID_RESERVED CFE_SB_MSGID_WRAP_VALUE(-1)
+#define CFE_SB_MSGID_RESERVED CFE_SB_MSGID_WRAP_VALUE(0)
 
 /**
  * \brief A literal of the CFE_SB_MsgId_t type representing an invalid ID
@@ -109,7 +109,7 @@
  * purposes (rvalue), #CFE_SB_MSGID_RESERVED should be used instead.
  * However, in the current implementation, they are equivalent.
  */
-#define CFE_SB_INVALID_MSG_ID CFE_SB_MSGID_C(-1)
+#define CFE_SB_INVALID_MSG_ID CFE_SB_MSGID_C(0)
 
 /**
  * \brief Cast/Convert a generic CFE_ResourceId_t to a CFE_SB_PipeId_t

modules/msg/ut-coverage/test_cfe_msg_msgid_shared.c

@@ -46,7 +46,7 @@ void Test_MSG_GetTypeFromMsgId(void)
     UtAssert_INT32_EQ(Test_MSG_NotZero(&msg), 0);
 
     UtPrintf("Bad parameter tests, Invalid message ID");
-    UtAssert_INT32_EQ(CFE_MSG_GetTypeFromMsgId(CFE_SB_INVALID_MSG_ID, &actual), CFE_MSG_BAD_ARGUMENT);
+    UtAssert_INT32_EQ(CFE_MSG_GetTypeFromMsgId(CFE_SB_ValueToMsgId(-1), &actual), CFE_MSG_BAD_ARGUMENT);
 
     UtPrintf("Set to all F's, test cmd and tlm");
     memset(&msg, 0xFF, sizeof(msg));

modules/msg/ut-coverage/test_cfe_msg_msgid_v1.c

@@ -56,14 +56,14 @@ void Test_MSG_MsgId(void)
     UtAssert_INT32_EQ(CFE_MSG_SetMsgId(&msg, CFE_SB_ValueToMsgId(0xFFFF)), CFE_MSG_BAD_ARGUMENT);
     UtAssert_INT32_EQ(Test_MSG_NotZero(&msg), 0);
 
-    UtPrintf("Set msg to all F's, set msgid to 0 and verify");
+    UtPrintf("Set msg to all F's, set msgid to 1 and verify");
     memset(&msg, 0xFF, sizeof(msg));
     CFE_UtAssert_SUCCESS(CFE_MSG_GetMsgId(&msg, &msgid));
     UtAssert_INT32_EQ(CFE_SB_MsgIdToValue(msgid), 0xFFFF);
-    CFE_UtAssert_SUCCESS(CFE_MSG_SetMsgId(&msg, CFE_SB_ValueToMsgId(0)));
+    CFE_UtAssert_SUCCESS(CFE_MSG_SetMsgId(&msg, CFE_SB_ValueToMsgId(1)));
     UT_DisplayPkt(&msg, sizeof(msg));
     CFE_UtAssert_SUCCESS(CFE_MSG_GetMsgId(&msg, &msgid));
-    UtAssert_INT32_EQ(CFE_SB_MsgIdToValue(msgid), 0);
+    UtAssert_INT32_EQ(CFE_SB_MsgIdToValue(msgid), 1);
     UtAssert_INT32_EQ(Test_MSG_NotF(&msg), MSG_HDRVER_FLAG | MSG_APID_FLAG | MSG_TYPE_FLAG | MSG_HASSEC_FLAG);
 
     UtPrintf("Set msg to all 0, set msgid to max and verify");

modules/sb/ut-coverage/sb_UT.c

@@ -91,7 +91,7 @@ const CFE_SB_MsgId_t SB_UT_LAST_VALID_MID = CFE_SB_MSGID_WRAP_VALUE(CFE_PLATFORM
  * This is a  "borderline" value to test the limits of the validity checking
  * The specific value depends on how MsgId is actually defined internally
  */
-const CFE_SB_MsgId_t SB_UT_FIRST_VALID_MID = CFE_SB_MSGID_WRAP_VALUE(0);
+const CFE_SB_MsgId_t SB_UT_FIRST_VALID_MID = CFE_SB_MSGID_WRAP_VALUE(1);
 
 /*
  * A MsgId value which is in the middle of the valid range
@@ -1480,15 +1480,15 @@ void Test_SB_Cmds_SendPrevSubs(void)
     NumEvts = 2; /* one for each pipe create */
 
     /* Two full pkts to be sent plus five entries in a partial pkt, skipping MSGID 0x0D */
-    for (i = 0; i < CFE_SB_SUB_ENTRIES_PER_PKT * 2 + 5; i++)
+    for (i = 1; i < (CFE_SB_SUB_ENTRIES_PER_PKT * 2) + 6; i++)
     {
         /* Skip subscribing to ALLSUBS mid. This is the one we are testing.
          * MsgID for this in CCSDS v.1 was 0x180d so this MID did not appear in the
          * SB sub list. This results in multiple NO_SUBS_EID sent which we are not
          * testing here so it is irrelevant
          * For CCSDS v.2 CFE_SB_ALLSUBS_TLM_MID (0x0d) now appears in the
          * SB subscription list and thus we must skip adding 0x0D to the list
-         * as we were going from MSGID 0-45 (0x00-0x2D)
+         * as we were going from MSGID 1-46 (0x01-0x2E)
          * */
         if (i != CFE_SB_ALLSUBS_TLM_MID)
         {
@@ -1533,7 +1533,7 @@ void Test_SB_Cmds_SendPrevSubs(void)
     /* Round out the number to three full pkts in order to test branch path
      * coverage, MSGID 0x0D was skipped in previous subscription loop
      */
-    for (; i < CFE_SB_SUB_ENTRIES_PER_PKT * 3; i++)
+    for (; i < (CFE_SB_SUB_ENTRIES_PER_PKT * 3) + 1; i++)
     {
         CFE_UtAssert_SETUP(CFE_SB_Subscribe(CFE_SB_ValueToMsgId(i), PipeId1));
         NumEvts += 1;
@@ -2571,18 +2571,18 @@ void Test_Subscribe_MaxMsgIdCount(void)
     {
         if (i < CFE_PLATFORM_SB_MAX_MSG_IDS)
         {
-            CFE_UtAssert_SETUP(CFE_SB_Subscribe(CFE_SB_ValueToMsgId(i), PipeId2));
+            CFE_UtAssert_SETUP(CFE_SB_Subscribe(CFE_SB_ValueToMsgId(1 + i), PipeId2));
         }
         else
         {
-            UtAssert_INT32_EQ(CFE_SB_Subscribe(CFE_SB_ValueToMsgId(i), PipeId2), CFE_SB_MAX_MSGS_MET);
+            UtAssert_INT32_EQ(CFE_SB_Subscribe(CFE_SB_ValueToMsgId(1 + i), PipeId2), CFE_SB_MAX_MSGS_MET);
         }
     }
 
     UtAssert_UINT32_EQ(CFE_SB_Global.StatTlmMsg.Payload.PeakMsgIdsInUse, CFE_PLATFORM_SB_MAX_MSG_IDS);
     CFE_UtAssert_EVENTSENT(CFE_SB_MAX_MSGS_MET_EID);
 
-    CFE_UtAssert_SUCCESS(CFE_SB_Subscribe(CFE_SB_ValueToMsgId(0), PipeId1));
+    CFE_UtAssert_SUCCESS(CFE_SB_Subscribe(CFE_SB_ValueToMsgId(1), PipeId1));
     UtAssert_UINT32_EQ(CFE_SB_Global.StatTlmMsg.Payload.PeakMsgIdsInUse, CFE_PLATFORM_SB_MAX_MSG_IDS);
 
     CFE_UtAssert_TEARDOWN(CFE_SB_DeletePipe(PipeId0));