rbus: fix unreachable code in rbus_open error handling

[svc-rdkeportal01]

Issue Fixed

Coverity Defect: UNREACHABLE
CWE: CWE-561 (Dead Code)
Severity: Medium
Function: rbus_open
File: src/rbus/rbus.c

Root Cause

The function rbus_open has unreachable code after a return statement:

RBUSLOG_INFO(" rbus open (%s) success", componentName);
return RBUS_ERROR_SUCCESS;

// ❌ UNREACHABLE: This code can never be executed!
if((err = rbus_unregisterObj(componentName)) != RBUSCORE_SUCCESS)
    RBUSLOG_ERROR("(%s): unregisterObj error %d", componentName, err);

exit_error2:
    // ... more cleanup

The rbus_unregisterObj cleanup code is placed after the return statement, making it impossible to reach. Additionally, when rbusHandle_TimeoutValuesInit fails, it does goto exit_error2, which skips this cleanup entirely.

Changes Made

1. Added new error label exit_error3:

return RBUS_ERROR_SUCCESS;

exit_error3:  // ✅ New label makes code reachable

if((err = rbus_unregisterObj(componentName)) != RBUSCORE_SUCCESS)
    RBUSLOG_ERROR("(%s): unregisterObj error %d", componentName, err);

exit_error2:

2. Changed goto target:

if (rbusHandle_TimeoutValuesInit(tmpHandle) != 0)
{
    RBUSLOG_ERROR("(%s): rbusHandle_TimeoutValuesInit failed", componentName);
    goto exit_error3;  // ✅ Changed from exit_error2
}

Why This Fix is Correct

1. Makes code reachable - The cleanup code can now be executed via goto
2. Proper error handling - When TimeoutValuesInit fails, it properly unregisters the object
3. Maintains cleanup order - Error labels cascade properly: exit_error3 → exit_error2 → exit_error1 → exit_error0
4. Simple fix - Just adds a label and changes one goto target

Error Handling Flow

Before (Buggy):

TimeoutValuesInit fails → goto exit_error2 → skips rbus_unregisterObj

After (Fixed):

TimeoutValuesInit fails → goto exit_error3 → calls rbus_unregisterObj → falls through to exit_error2

Testing

• Verified fix compiles without errors
• Checked that error handling flow is correct
• Confirmed cleanup code is now reachable