On Tue, 2011-05-03 at 10:44 +0200, Karel Zak wrote:
> On Mon, May 02, 2011 at 10:04:13PM -0300, Davidlohr Bueso wrote:
> > From: Davidlohr Bueso <dave@xxxxxxx>
> > Date: Mon, 2 May 2011 21:48:05 -0300
> >
> > This patch introduces the first function in the file,
> > proc_getthreads(), which obtains the threads for a given PID.
>
> Cool!
>
> What about to use more talkative a easily extendible API:
>
> struct proc_tasks *ts;
> pid_t tid;
>
> ts = proc_open_tasks(<pid>);
>
> while(proc_next_tid(ts, &tid) == 0) {
> ...
> }
>
> proc_close_tasks(ts);
>
> where
> - /proc/#/tasks 'DIR *' is in 'struct proc_tasks'
> - opendir() in proc_open_tasks()
> - readdir() in proc_next_tid()
> - closedir() in proc_close_tasks()
>
OK, you want this fancier than I thought :) My initial focus was
something quick and simple, ala strutils.
> one day we can easily extend this API and add for example
>
> proc_next_task_cpuset(struct proc_tasks *, pid_t *tid, cpu_set_t *)
>
> or whatever. It's also a simple way how to avoid the realloc().
>
> > + char path[18]; /* lenght of /proc/<5digits-pid>/task/ */
I guess we can use something based on BUFSIZ (like BUFSIZ/2?). No need
to make it too big.
>
> pid_t is __S32_TYPE, so it would be better to use something larger.
>
> > + sprintf(path, "/proc/%d/task/", pid);
> > +
> > + dir = opendir(path);
> > + if (!dir)
> > + goto ret;
> > +
> > + while ((d = readdir(dir))) {
> > + if (!strcmp(d->d_name, ".") || !strcmp(d->d_name, ".."))
> > + continue;
> > + list = (i == 0) ? malloc(sizeof(pid_t)) :
> > + realloc(list, (i + 1) * sizeof(pid_t));
>
> unnecessary, realloc(NULL, <size>) works like malloc(<size>);
>
> > + list[i++] = (pid_t) strtol(d->d_name, (char **) NULL, 10);
>
> this should be more paranoid ;-)
Something like strtol_or_err()?
Thanks,
Davidlohr
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