Re: [libvirt] [PATCH] dnsmasq: Fix parsing of the version number
On 12/06/2012 06:34 AM, Michal Privoznik wrote:
If the debugging is enabled, the virCommand subsystem catches debug
messages in the command output as well. In that case, we can't assume
the string corresponding to command's stdout will start with specific
prefix. But the prefix can be moved deeper in the string. This bug
shows itself when parsing dnsmasq output:
2012-12-06 11:18:11.445+0000: 18491: error :
dnsmasqCapsSetFromBuffer:664 : internal error cannot parse
/usr/sbin/dnsmasq version number in '2012-12-06 11:11:02.232+0000:
18492: debug : virFileClose:72 : Closed fd 22'
We can clearly see that the output of dnsmasq --version
doesn't start with expected "Dnsmasq version " string but a libvirt
debug output.
This is a bug in virCommand, and should also affect
qemuCapsParseHelpStr(). Is there no way to fix it at the source, rather
than working around it like this?
---
src/util/dnsmasq.c | 4 ++--
1 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/src/util/dnsmasq.c b/src/util/dnsmasq.c
index 4f210d2..de0293a 100644
--- a/src/util/dnsmasq.c
+++ b/src/util/dnsmasq.c
@@ -641,9 +641,9 @@ dnsmasqCapsSetFromBuffer(dnsmasqCapsPtr caps, const char *buf)
caps->noRefresh = true;
- p = STRSKIP(buf, DNSMASQ_VERSION_STR);
- if (!p)
+ if (!(p = strstr(buf, DNSMASQ_VERSION_STR)))
goto fail;
+ p += sizeof(DNSMASQ_VERSION_STR) - 1;
Why -1 ? That happens to work, but wouldn't if the version string didn't
end with a space.
virSkipSpaces(&p);
if (virParseVersionString(p, &caps->version, true) < 0)
goto fail;
I'd rather make sure that nobody has a bright idea on how to fix
virCommand before pushing this.