Date: Sun, 12 Aug 2018 23:58:35 +0300 From: Konstantin Belousov <kostikbel@gmail.com> To: Willem Jan Withagen <wjw@digiware.nl> Cc: FreeBSD Hackers <freebsd-hackers@freebsd.org> Subject: Re: Write a version for pthread_get_name_np Message-ID: <20180812205835.GB2340@kib.kiev.ua> In-Reply-To: <42689feb-9bd4-429b-63d7-b9193123ee47@digiware.nl> References: <7fa2b876-9397-da2b-cb29-56badf11b66d@ecoracks.nl> <42689feb-9bd4-429b-63d7-b9193123ee47@digiware.nl>
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On Sun, Aug 12, 2018 at 10:33:06PM +0200, Willem Jan Withagen wrote:
> Hi,
>
> For some porting I'm trying to write a pthread_get_name_np(), but
> I have run into a snag....
> Tried some the the procstat code I would come up with:
>
> int pthread_get_name_np(pthread_t *thread,
> ššššššššššššššššššššššš char *name, size_t len){
> ššš struct procstat *procstat;
> ššš int pid = getpid();
> ššš unsigned int count, i;
> ššš struct kinfo_proc *kip, *kipp;
>
> ššš procstat = procstat_open_sysctl();
> ššš kip = procstat_getprocs(procstat, KERN_PROC_PID | KERN_PROC_INC_THREAD,
> ššššššššššš pid, &count);
> ššš for (i = 0; i < count; i++) {
> ššš ššš kipp = &kip[i];
> ššš ššš printf("thread: %ld(0x%lx), %ld(0x%lx)\n", thread, thread,
> kipp->ki_tid, kipp->ki_tid);
> ššš ššš if (thread == kipp->ki_tid) {
> ššš ššš ššš kinfo_proc_thread_name(kipp, name, len);
> ššš ššš }
> ššš }
> ššš return 0;
> }
>
> Problem only is that the TID value in what procstat_getprocs returns in
> ki_tid is nowhere near
> what pthread_self() returns.
> But both manual page and the include file describe the value as Thread ID.
> Only in sys/user.h the type is
> ššš lwpid_t ki_tid;šššššššššššššššš /* XXXKSE thread id */
>
> What do I need to translate one tid into the other so I can really
> compare them?
You need to cast pthread_t * to struct thread *, this is an internal
libthr structure which represents the thread in userspace. The
structure field tid gives you the tid you want to pass to sysctl.
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