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Re: [libvirt] [PATCHv3] lxc: Fix return values of veth.c functions - complete



 On 07/29/2010 01:53 PM, Ryota Ozaki wrote:
On Fri, Jul 30, 2010 at 2:32 AM, Laine Stump<laine laine org>  wrote:
From: Ryota Ozaki<ozaki ryota gmail com>

Previously, the functions in src/lxc/veth.c could sometimes return
positive values on failure rather than -1. This made accurate error
reporting difficult, and led to one failure to catch an error in a
calling function.

This patch makes all the functions in veth.c consistently return 0 on
success, and -1 on failure. It also fixes up the callers to the veth.c
functions where necessary.

Note that this patch may be related to the bug:

  https://bugzilla.redhat.com/show_bug.cgi?id=607496.

It will not fix the bug, but should unveil what happens.

* po/POTFILES.in - add veth.c, which previously had no translatable strings
* src/lxc/lxc_controller.c
* src/lxc/lxc_container.c
* src/lxc/lxc_driver.c    - fixup callers to veth.c, and remove error logs,
                            as they are now done in veth.c
* src/lxc/veth.c - make all functions consistently return -1 on error.
* src/lxc/veth.h - use ATTRIBUTE_NONNULL to protect against NULL args.
---
Changes from Ozaki's original patch:

1) virAsprintf() will return the number of characters in the new
   string on success, not 0, so we need to only set rc if it fails
   (<  0). Assigning rc on success causes the caller to falsely believe
   the function failed.

2) lxcVmCleanup was always doing the if (WIFEXITED() ...) even
   if waitpid had failed. I don't know if the behavior of WIFEXITED
   is defined if waitpid fails, but all the other uses I can find
   avoid calling WIFEXITED and WEXITSTATUS if waitpid fails, so that's
   what I did here. Also changed to return -1 if waitpid fails or
   WEXITSTATUS != 0.

3) lxcSetupInterfaces - rather than explicitly setting rc from the
   return of functions, since it defaults to -1, I just goto
   error_exit if the functions return<  0. That's just cosmetic. The
   real problem is that rc was being set from brAddInterface, which
   returns>  0 on failure (note error log of errno from brAddInterface
   fixed in v3).

4) assigning "rc = -1" at the beginning of each veth.c function is a
   dead store, since it will always be set by the call to virRun(). This
   causes coverity code analysis tool to report problems.
ACK. Thanks, Laine!

Pushed.


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