Fix #888, better return codes from OS_SymbolTableDump_Impl

Improve the error codes from this function.

- Introduces a new error "OS_ERR_OUTPUT_TOO_LARGE" if the size
limit was insufficient (instead of OS_SUCCESS).
- Return OS_ERROR if an empty file was written - this likely
indicates some fundamental issue with the VxWorks symbol table.
- Return OS_ERR_NAME_TOO_LONG if one of the symbol names was
too long, (instead of generic OS_ERROR).

Improve unit test to check for/verify these responses.

src/os/inc/osapi-error.h

@@ -84,6 +84,7 @@ typedef char os_err_name_t[OS_ERROR_NAME_LENGTH];
 #define OS_ERR_STREAM_DISCONNECTED     (-37) /**< @brief Stream disconnected */
 #define OS_ERR_OPERATION_NOT_SUPPORTED (-38) /**< @brief Requested operation not support on supplied object(s) */
 #define OS_ERR_INVALID_SIZE            (-40) /**< @brief Invalid Size */
+#define OS_ERR_OUTPUT_TOO_LARGE        (-41) /**< @brief Size of output exceeds limit  */
 
 /*
 ** Defines for File System Calls

src/os/vxworks/src/os-impl-symtab.c

@@ -175,7 +175,7 @@ BOOL OS_SymTableIterator_Impl(char *name, SYM_VALUE val, SYM_TYPE type, _Vx_usr_
     if (memchr(name, 0, OS_MAX_SYM_LEN) == NULL)
     {
         OS_DEBUG("%s(): symbol name too long\n", __func__);
-        state->StatusCode = OS_ERROR;
+        state->StatusCode = OS_ERR_NAME_TOO_LONG;
         return (false);
     }
 
@@ -190,6 +190,7 @@ BOOL OS_SymTableIterator_Impl(char *name, SYM_VALUE val, SYM_TYPE type, _Vx_usr_
         ** However this is not considered an error, just a stop condition.
         */
         OS_DEBUG("%s(): symbol table size exceeded\n", __func__);
+        state->StatusCode = OS_ERR_OUTPUT_TOO_LARGE;
         return (false);
     }
 
@@ -264,6 +265,16 @@ int32 OS_SymbolTableDump_Impl(const char *filename, size_t size_limit)
         close(state->fd);
     }
 
+    /*
+     * If output size was zero this means a failure of the symEach call,
+     * in that it didn't iterate over anything at all.
+     */
+    if (state->StatusCode == OS_SUCCESS && state->CurrSize == 0)
+    {
+        OS_DEBUG("%s(): No symbols found!\n", __func__);
+        state->StatusCode = OS_ERROR;
+    }
+
     return (state->StatusCode);
 
 } /* end OS_SymbolTableDump_Impl */

src/unit-test-coverage/vxworks/adaptors/inc/ut-adaptor-symtab.h

@@ -31,5 +31,6 @@
 #include "common_types.h"
 
 int32 UT_SymTabTest_CallIteratorFunc(const char *name, void *val, size_t TestSize, size_t SizeLimit);
+int32 UT_SymTabTest_GetIteratorStatus(void);
 
 #endif /* UT_ADAPTOR_SYMTAB_H  */

src/unit-test-coverage/vxworks/adaptors/src/ut-adaptor-symtab.c

@@ -47,3 +47,11 @@ int32 UT_SymTabTest_CallIteratorFunc(const char *name, void *val, size_t TestSiz
      */
     return OS_SymTableIterator_Impl((char *)name, (OCS_SYM_VALUE)val, 0, 0, 0);
 }
+
+/*
+ * Gets the current status of the iterator function
+ */
+int32 UT_SymTabTest_GetIteratorStatus(void)
+{
+    return OS_VxWorks_SymbolDumpState.StatusCode;
+}

src/unit-test-coverage/vxworks/src/coveragetest-symtab.c

@@ -67,25 +67,51 @@ void Test_OS_SymTableIterator_Impl(void)
      */
     uint32 Data = 0;
 
+    /* nominal case - nothing goes wrong */
     OSAPI_TEST_FUNCTION_RC(UT_SymTabTest_CallIteratorFunc("ut", &Data, 100, 1000), true);
+    OSAPI_TEST_FUNCTION_RC(UT_SymTabTest_GetIteratorStatus(), OS_SUCCESS);
+
+    /* Check case where next entry will exceed size limit */
     OSAPI_TEST_FUNCTION_RC(UT_SymTabTest_CallIteratorFunc("ut", &Data, 100, 101), false);
+    OSAPI_TEST_FUNCTION_RC(UT_SymTabTest_GetIteratorStatus(), OS_ERR_OUTPUT_TOO_LARGE);
+
+    /* Check case where entry has a name that is too long */
     UT_SetDefaultReturnValue(UT_KEY(OCS_memchr), OS_ERROR);
     OSAPI_TEST_FUNCTION_RC(UT_SymTabTest_CallIteratorFunc("ut", &Data, 100, 1000), false);
+    OSAPI_TEST_FUNCTION_RC(UT_SymTabTest_GetIteratorStatus(), OS_ERR_NAME_TOO_LONG);
     UT_ClearDefaultReturnValue(UT_KEY(OCS_memchr));
+
+    /* Check case where writing to file fails */
     UT_SetDefaultReturnValue(UT_KEY(OCS_write), -1);
     OSAPI_TEST_FUNCTION_RC(UT_SymTabTest_CallIteratorFunc("ut", &Data, 100, 1000), false);
+    OSAPI_TEST_FUNCTION_RC(UT_SymTabTest_GetIteratorStatus(), OS_ERROR);
     UT_ClearDefaultReturnValue(UT_KEY(OCS_write));
 }
 
+static int32 UT_symEachHook(void *UserObj, int32 StubRetcode, uint32 CallCount, const UT_StubContext_t *Context)
+{
+    uint32 Data = 0;
+    UT_SymTabTest_CallIteratorFunc("ut", &Data, 100, 1000);
+    return StubRetcode;
+}
+
 void Test_OS_SymbolTableDump_Impl(void)
 {
     /* Test Case For:
      * int32 OS_SymbolTableDump_Impl ( const char *filename, uint32 SizeLimit )
      */
-    OSAPI_TEST_FUNCTION_RC(OS_SymbolTableDump_Impl("file", 10000), OS_SUCCESS);
+
+    /* With no action in symEach(), this will yield an empty file, which is an error */
+    OSAPI_TEST_FUNCTION_RC(OS_SymbolTableDump_Impl("file", 10000), OS_ERROR);
+
+    /* Check failure in open() */
     UT_SetDefaultReturnValue(UT_KEY(OCS_open), -1);
     OSAPI_TEST_FUNCTION_RC(OS_SymbolTableDump_Impl("file", 10000), OS_ERROR);
     UT_ClearDefaultReturnValue(UT_KEY(OCS_open));
+
+    /* Set up a hook function for symEach() to provide at least one entry */
+    UT_SetHookFunction(UT_KEY(OCS_symEach), UT_symEachHook, NULL);
+    OSAPI_TEST_FUNCTION_RC(OS_SymbolTableDump_Impl("file", 10000), OS_SUCCESS);
 }
 
 /* ------------------- End of test cases --------------------------------------*/