On Thu, Nov 12, 2020 at 3:31 AM Steven Rostedt <rostedt@xxxxxxxxxxx> wrote:
>
> On Tue, 10 Nov 2020 14:22:48 +0200
> "Tzvetomir Stoyanov (VMware)" <tz.stoyanov@xxxxxxxxx> wrote:
> \> +
> > +/**
> > + * tracefs_instances_walk - Iterate through all ftrace instances in the system
> > + * @callback: user callback, called for each instance. Instance name is passed
> > + * as input parameter. If the @callback returns non-zero,
> > + * the iteration stops.
> > + * @context: user context, passed to the @callback.
> > + *
> > + * Returns -1 in case of an error, 0 otherwise.
> > + */
> > +int tracefs_instances_walk(int (*callback)(const char *, void *), void *context)
> > +{
> > + struct dirent *dent;
> > + char *path = NULL;
> > + DIR *dir = NULL;
> > + struct stat st;
> > + int fret = -1;
> > + int ret;
> > +
> > + path = tracefs_get_tracing_file("instances");
> > + if (!path)
> > + return -1;
> > + ret = stat(path, &st);
> > + if (ret < 0 || !S_ISDIR(st.st_mode))
> > + goto out;
> > +
> > + dir = opendir(path);
> > + if (!dir)
> > + goto out;
> > + fret = 0;
> > + while ((dent = readdir(dir))) {
> > + char *instance;
> > +
> > + if (strcmp(dent->d_name, ".") == 0 ||
> > + strcmp(dent->d_name, "..") == 0)
> > + continue;
> > + instance = trace_append_file(path, dent->d_name);
> > + ret = stat(instance, &st);
> > + free(instance);
> > + if (ret < 0 || !S_ISDIR(st.st_mode))
> > + continue;
> > + if (callback(dent->d_name, context))
>
> Should we notify the caller of this function if the callback returned
> non zero?
>
>
> > + break;
> > + }
> > +
> > +out:
>
> Hmm, would dir ever be anything but non NULL here?
>
It could be NULL if opendir() or stat() fails.
Thanks, Steve! I'll address your comments in the next version of the patch set.
> -- Steve
>
> > + if (dir)
> > + closedir(dir);
> > + tracefs_put_tracing_file(path);
> > + return fret;
> > +}
--
Tzvetomir (Ceco) Stoyanov
VMware Open Source Technology Center
|