Ensure readlink uses correct buffer size in get_exec_name

[dannlee]

There is an issue with the get_exec_name function where the executable name could be truncated if the total path length exceeded 32 characters.

The readlink function was using p_exec_name_maxsize (32) as the buffer size for the global buffer g_buffer (4096).
When the path to the /proc/[pid]/exe link exceeded 32 characters, readlink truncated the output, causing incorrect or incomplete executable names.

Updated the readlink call to use the buffer size: sizeof(g_buffer) - 1.
This prevents the truncation of the executable path during the readlink operation.
The executable name is still limited to under 32 characters when copied to p_exec_name via:
strncpy(p_exec_name, l_name_ptr + 1, p_exec_name_maxsize - 1);