hastd segfaults reading metadata from not initialized provider

[Pawel Jakub Dawidek]

On Mon, Apr 26, 2010 at 11:07:31PM +0300, Mikolaj Golub wrote:
> Hi,
> 
> When configuring a new provider if one forgets to do 
> 
> hastctl create tank
> 
> before 
> 
> hastctl role primary tank

In my tests I cannot reproduce it. If metadata is empty hastd should
notice that, but check for NULL was missing anyway.

> the worker core dumps on reading metadata:
> 
> (gdb) bt
> #0  strcmp () at /usr/src/lib/libc/i386/string/strcmp.S:61
> #1  0x0804fa18 in metadata_read (res=0x284cb600, openrw=true) at /usr/src/sbin/hastd/metadata.c:120
> #2  0x080570ac in init_local (res=0x284cb600) at /usr/src/sbin/hastd/primary.c:425
> #3  0x08057f88 in hastd_primary (res=0x284cb600) at /usr/src/sbin/hastd/primary.c:754
> #4  0x0804e270 in child_exit () at /usr/src/sbin/hastd/hastd.c:145
> #5  0x0804edd1 in main_loop () at /usr/src/sbin/hastd/hastd.c:389
> #6  0x0804f3d8 in main (argc=0, argv=0xbfbfed84) at /usr/src/sbin/hastd/hastd.c:520
> Current language:  auto; currently asm
> (gdb) fr 1
> #1  0x0804fa18 in metadata_read (res=0x284cb600, openrw=true) at /usr/src/sbin/hastd/metadata.c:120
> 120             if (strcmp(str, res->hr_name) != 0) {
> Current language:  auto; currently c
> (gdb) list
> 115                     ebuf_free(eb);
> 116                     goto fail;
> 117             }
> 118
> 119             str = nv_get_string(nv, "resource");
> 120             if (strcmp(str, res->hr_name) != 0) {
> 121                     pjdlog_error("Provider %s is not part of resource %s.",
> 122                         res->hr_localpath, res->hr_name);
> 123                     nv_free(nv);
> 124                     goto fail;
> (gdb) p str
> $1 = 0x0
> 
> In the attached patch the check for str is added so we would have a
> termination with the error message instead of a core dump:
> 
> Apr 26 22:46:06 hasta hastd: [tank] (primary) Metadata read from /dev/ad6 is invalid.
> Apr 26 22:46:06 hasta hastd: [tank] (primary) Worker process failed (pid=6196, status=66).

I fixed it a bit different. In general nv API is constructued in a way
that the consumer might execute various calls and check for error at the
end. This is what we do there already, only (str != NULL) check was
missing. Thanks for the report, I committed fix to HEAD.

-- 
Pawel Jakub Dawidek                       http://www.wheelsystems.com
pjd at FreeBSD.org                           http://www.FreeBSD.org
FreeBSD committer                         Am I Evil? Yes, I Am!
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