Re: [Qemu-devel] [PATCH v6 5/9] qemu-log: support simple pid substitution in logfile

[Alex Bennée]

Alex Bennée  writes:

> 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 
> Reviewed-by: Leandro Dorileo 
> Reviewed-by: Aurelien Jarno 
>
> ---
> v5
>   - add another r-b
> ---
>  util/log.c | 17 +++--
>  1 file changed, 15 insertions(+), 2 deletions(-)
>
> diff --git a/util/log.c b/util/log.c
> index c89b226..3988b5d 100644
> --- a/util/log.c
> +++ b/util/log.c
> @@ -75,11 +75,24 @@ 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")) {

Just realised I missed the strrstr -> strstr fix. Not that it makes a
lot of difference in this case.

> +/* 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);
>  }


--
Alex Bennée

[Qemu-devel] [PATCH v6 5/9] qemu-log: support simple pid substitution in logfile

[Alex Bennée]

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 
Reviewed-by: Leandro Dorileo 
Reviewed-by: Aurelien Jarno 

---
v5
  - add another r-b
---
 util/log.c | 17 +++--
 1 file changed, 15 insertions(+), 2 deletions(-)

diff --git a/util/log.c b/util/log.c
index c89b226..3988b5d 100644
--- a/util/log.c
+++ b/util/log.c
@@ -75,11 +75,24 @@ 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);
 }
-- 
2.7.0