rbus: check return value of remove() in rbus_close

[svc-rdkeportal01]

Issue Fixed

Coverity Defect: CHECKED_RETURN
CWE: CWE-252 (Unchecked Return Value)
Severity: Medium
Function: rbus_close
File: src/rbus/rbus.c

Root Cause

The function rbus_close() calls remove() to delete a temporary file (/tmp/.rbus/<pid>_<componentId>) but does not check the return value. This could mask failures in file deletion, potentially leading to:

• Accumulated temporary files if deletion consistently fails
• Undetected permission issues
• Disk space issues going unnoticed

Changes Made

Added return value check for remove() with error logging:

int removeRet = remove(filename);
if(removeRet != 0 && errno != ENOENT)
{
    RBUSLOG_ERROR("remove(%s) failed with error %d", filename, errno);
}

Key points:

• Captures return value in removeRet
• Checks if removal failed (removeRet != 0)
• Ignores ENOENT (file doesn't exist) as this is not an error condition
• Logs actual errors with filename and errno for debugging

Also added #include <errno.h> to access errno.

Why This Fix is Correct

1. Detects real failures - Logs when file removal fails for actual errors
2. Ignores expected cases - ENOENT is not logged (file may not exist)
3. Aids debugging - Error message includes filename and errno
4. No functional change - Only adds logging, doesn't change behavior
5. Matches best practices - Checking system call return values is standard

Testing

• Verified fix compiles without errors
• Checked that errno is properly included
• Confirmed error logging only triggers on actual failures