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[RFC,2/4] qemu-log: support simple pid substitution in logfile

Message ID 1395844634-11729-3-git-send-email-alex.bennee@linaro.org
State Superseded
Headers show

Commit Message

Alex Bennée March 26, 2014, 2:37 p.m. UTC
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>

Comments

Leandro Dorileo March 26, 2014, 6:50 p.m. UTC | #1
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.
Alex Bennée March 27, 2014, 9:59 a.m. UTC | #2
Leandro Dorileo <l@dorileo.org> writes:

> 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().
<snip>
>
> Looks good to me.

Is that a Reviewed-by? If you include a Reviewed-by tag it makes it
easier to copy and paste into the commit for the next iteration.
Leandro Dorileo March 28, 2014, 12:19 p.m. UTC | #3
On Thu, Mar 27, 2014 at 09:59:21AM +0000, Alex Bennée wrote:
> 
> Leandro Dorileo <l@dorileo.org> writes:
> 
> > 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().
> <snip>
> >
> > Looks good to me.
> 
> Is that a Reviewed-by? If you include a Reviewed-by tag it makes it
> easier to copy and paste into the commit for the next iteration.

Sure, you can add

Reviewed-by: Leandro Dorileo <l@dorileo.org>
diff mbox

Patch

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);
 }