Re: [Qemu-devel] [RFC PATCH 2/4] qemu-log: support simple pid substitution in logfile

[Leandro Dorileo <l@dorileo.org>]

On Wed, Mar 26, 2014 at 02:37:12PM +0000, alex.bennee@linaro.org wrote:
> From: Alex Bennée <alex.bennee@linaro.org>
> 
> When debugging stuff that occurs over several forks it would be useful
> not to keep overwriting the one logfile you've set-up. This allows a
> simple %d to be included once in the logfile parameter which is
> substituted with getpid().
> 
> Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
> 
> diff --git a/qemu-log.c b/qemu-log.c
> index 35bbb56..2897596 100644
> --- a/qemu-log.c
> +++ b/qemu-log.c
> @@ -81,11 +81,24 @@ void do_qemu_set_log(int log_flags, bool use_own_buffers)
>          qemu_log_close();
>      }
>  }
> -
> +/*
> + * Allow the user to include %d in their logfile which will be
> + * substituted with the current PID. This is useful for debugging many
> + * nested linux-user tasks but will result in lots of logs.
> + */
>  void qemu_set_log_filename(const char *filename)
>  {
>      g_free(logfilename);
> -    logfilename = g_strdup(filename);
> +    if (g_strrstr(filename, "%d")) {
> +        /* if we are going to format this we'd better validate first */
> +        if (g_regex_match_simple("^[^%]+%d[^%]+$", filename, 0, 0)) {
> +            logfilename = g_strdup_printf(filename, getpid());
> +        } else {
> +            g_error("Bad logfile format: %s", filename);
> +        }
> +    } else {
> +        logfilename = g_strdup(filename);
> +    }
>      qemu_log_close();
>      qemu_set_log(qemu_loglevel);
>  }

Looks good to me.

-- 
Leandro Dorileo