[sheepdog] [PATCH v1] fix null pointer reference in dog command

[Ruoyu]

On 2014年09月23日 11:31, meng wrote:
>
> 在 14-9-23 上午11:25, Ruoyu 写道:
>>
>> On 2014年09月23日 11:11, Meng An wrote:
>>> From: Meng An <anmeng.an at alibaba-inc.com>
>>>
>>> In function do_generic_subcommand, we should check if argv[optind] 
>>> is NULL
>>> before using it.
>> Thanks, but why we should check it first?
> for example, if we run the command "dog node log level -a 127.0.0.1" 
> without setting the subcommand "set/get/list",
> it will cause Segment Fault, because in funtion do_generic_subcommand, 
> we using argv[optind] directly:
In my environment, it works fine.

$ dog/dog node log level -a 127.0.0.1
Usage: dog node log level {set|get|list} [-a address] [-p port] [-h] [-T]
Available subcommands:
   set                     set new loglevel
   get                     get current loglevel
   list                    list available loglevels
Options:
   -a, --address           specify the daemon address (default: localhost)
   -p, --port              specify the daemon port
   -h, --help              display this help and exit
   -T, --time              show elapsed time

Have you run it on latest master?
>
> ***
> 248         for (i = 0; sub[i].name; i++) {
> 249                 unsigned long flags;
> 250
> 251                 if (strcmp(sub[i].name, argv[optind]))
> 252                         continue;
> 253
> ***
>
> Thanks,
> Meng
>>>
>>> Signed-off-by: Meng An <isolate000 at gmail.com>
>>> ---
>>>   dog/common.c |    3 +++
>>>   1 files changed, 3 insertions(+), 0 deletions(-)
>>>
>>> diff --git a/dog/common.c b/dog/common.c
>>> index 3c4f6f5..df49792 100644
>>> --- a/dog/common.c
>>> +++ b/dog/common.c
>>> @@ -238,6 +238,9 @@ int do_generic_subcommand(struct subcommand 
>>> *sub, int argc, char **argv)
>>>           sd_err("Too deep netsted subcommands, "
>>>                  "please expand MAX_SUBCMD_DEPTH");
>>>           exit(EXIT_USAGE);
>>> +    } else if (NULL == argv[optind]) {
>>> +        subcommand_usage(argv[1], argv[2], EXIT_USAGE);
>>> +        exit(EXIT_USAGE);
>>>       }
>>>         subcmd_stack[++subcmd_depth] = sub;
>>
>>
>