[Crash-utility] [PATCH] address compiler warning for extensions/trace.c

[qiaonuohan]

Hello Dave,

On 07/07/2015 11:20 PM, Dave Anderson wrote:
> Hello Qiao,
>
> With more recent versions of gcc, extensions/trace.c generates this warning:
>
>    $ make extensions
>    ...
>    gcc -Wall -g -shared -rdynamic -o trace.so trace.c -fPIC -DX86_64 -DLZO -DSNAPPY -DGDB_7_6
>    /tmp/ccSOIphT.o: In function 'ftrace_show':
>    /root/crash.git/extensions/trace.c:1560: warning: the use of 'mktemp' is dangerous, better use 'mkstemp'
>    ...
>    $
>
> I've attached an untested patch that replaces the mktemp() call with mkstemp().
> I believe the only behavioral difference is that mkstemp() will create the file
> automatically with permissions 600 and open flags of O_EXCL, whereas it is
> currently being opened with permissions 644 and flags (O_WRONLY | O_CREAT | O_TRUNC).

It seems good to me.

Acked-by: Qiao Nuohan <qiaonuohan at cn.fujitsu.com>

>
> Can you either ACK the patch, or address the warning as you would prefer?
>
> Thanks,
>    Dave
>
>
> use_mkstemp.patch
>
>
> diff --git a/extensions/trace.c b/extensions/trace.c
> index 8639fb2..9f81568 100644
> --- a/extensions/trace.c
> +++ b/extensions/trace.c
> @@ -1533,7 +1533,6 @@ static void ftrace_show(int argc, char *argv[])
>   	FILE *file;
>   	size_t ret;
>   	size_t nitems __attribute__ ((__unused__));
> -	char *unused __attribute__ ((__unused__));
>
>   	/* check trace-cmd */
>   	if (env_trace_cmd)
> @@ -1557,8 +1556,9 @@ static void ftrace_show(int argc, char *argv[])
>   	}
>
>   	/* dump trace.dat to the temp file */
> -	unused = mktemp(tmp);
> -	fd = open(tmp, O_WRONLY | O_CREAT | O_TRUNC, 0644);
> +	fd = mkstemp(tmp);

"tmp" will be modified to the path of the temporary file, good.

> +	if (fd < 0)
> +		return;
>   	if (trace_cmd_data_output(fd) < 0)
>   		goto out;
>


-- 
Regards
Qiao Nuohan