static analysis reports "Buffer not null terminated" issues in stx-nfv

[Ran An]

Brief Description
-----------------
  in some files, it use 'sncpy()' function which can not guarantee null termination of the string. This will lead a further security issue: "If the buffer is treated as a null terminated string in later operations, a buffer overflow or over-read may occur."

Severity
--------
 Major

Steps to Reproduce
------------------
  use function 'snprintf()' instead of 'sncpy()'

Expected Behavior
------------------
  static analysis do not report this issue

Actual Behavior
----------------
  static analysis report this issue

Reproducibility
---------------
Reproducible

System Configuration
--------------------
all

Static Analysis Reports
--------------------
Buffer not null terminated
If the buffer is treated as a null terminated string in later operations, a buffer overflow or over-read may occur.

host_instance_mgmt.c:266
  buffer_size_warning: Calling strncpy with a maximum size argument of 20 bytes on destination array instance->name of size 20 bytes might leave the destination string unterminated

similar cases at host_instance_mgmt.c:403, host_instance_mgmt.c:462

[Bruce Jones (brucej)]

Please update this bug with specific file and line number information for the static analysis issue. Make sure the bug has enough information for someone to find the problem in the code without access to the tool or the report.

[Ran An (an.ran)]

associated reviews addr: https://review.openstack.org/#/c/612221/