From mboxrd@z Thu Jan 1 00:00:00 1970 X-Msuck: nntp://news.gmane.org/gmane.linux.lib.musl.general/10454 Path: news.gmane.org!.POSTED!not-for-mail From: Felix Janda Newsgroups: gmane.linux.lib.musl.general Subject: Re: [PATCH RFC] add pthread_setname_np Date: Wed, 14 Sep 2016 23:43:51 -0400 Message-ID: <20160915034351.GA4973@nyan> References: <20160915030216.GA4535@nyan> <20160915032731.GE15995@brightrain.aerifal.cx> Reply-To: musl@lists.openwall.com NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Trace: blaine.gmane.org 1473911222 10742 195.159.176.226 (15 Sep 2016 03:47:02 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Thu, 15 Sep 2016 03:47:02 +0000 (UTC) User-Agent: Mutt/1.6.1 (2016-04-27) To: musl@lists.openwall.com Original-X-From: musl-return-10467-gllmg-musl=m.gmane.org@lists.openwall.com Thu Sep 15 05:46:59 2016 Return-path: Envelope-to: gllmg-musl@m.gmane.org Original-Received: from mother.openwall.net ([195.42.179.200]) by blaine.gmane.org with smtp (Exim 4.84_2) (envelope-from ) id 1bkNda-00028w-8Q for gllmg-musl@m.gmane.org; Thu, 15 Sep 2016 05:46:58 +0200 Original-Received: (qmail 5574 invoked by uid 550); 15 Sep 2016 03:46:58 -0000 Mailing-List: contact musl-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Original-Received: (qmail 5556 invoked from network); 15 Sep 2016 03:46:57 -0000 Resent-From: Felix Janda Resent-Date: Wed, 14 Sep 2016 23:46:07 -0400 Resent-Message-ID: <20160915034607.GA5155@nyan> Resent-To: musl@lists.openwall.com Mail-Followup-To: musl@lists.openwall.com Content-Disposition: inline In-Reply-To: <20160915032731.GE15995@brightrain.aerifal.cx> Xref: news.gmane.org gmane.linux.lib.musl.general:10454 Archived-At: Rich Felker wrote: Thanks for the review! > On Wed, Sep 14, 2016 at 11:02:16PM -0400, Felix Janda wrote: > > gdb's "info threads" displays the thread name. > > --- > > Should this function care about interrupted syscalls? > > Unless it's specified not to return EINTR I'm fine with it returning > EINTR. ok. Is it possible that write() is interrupted with partial data written (so that it won't return -1)? > > --- > > include/pthread.h | 1 + > > src/thread/pthread_setname_np.c | 21 +++++++++++++++++++++ > > 2 files changed, 22 insertions(+) > > create mode 100644 src/thread/pthread_setname_np.c > > > > diff --git a/include/pthread.h b/include/pthread.h > > index 3d2e0c4..94ef919 100644 > > --- a/include/pthread.h > > +++ b/include/pthread.h > > @@ -214,6 +214,7 @@ struct cpu_set_t; > > int pthread_getaffinity_np(pthread_t, size_t, struct cpu_set_t *); > > int pthread_setaffinity_np(pthread_t, size_t, const struct cpu_set_t *); > > int pthread_getattr_np(pthread_t, pthread_attr_t *); > > +int pthread_setname_np(pthread_t, const char *); > > int pthread_tryjoin_np(pthread_t, void **); > > int pthread_timedjoin_np(pthread_t, void **, const struct timespec *); > > #endif > > diff --git a/src/thread/pthread_setname_np.c b/src/thread/pthread_setname_np.c > > new file mode 100644 > > index 0000000..b7f7a4b > > --- /dev/null > > +++ b/src/thread/pthread_setname_np.c > > @@ -0,0 +1,21 @@ > > +#include > > +#include > > +#include > > + > > +#include "pthread_impl.h" > > + > > +int pthread_setname_np(pthread_t thread, const char *name) > > +{ > > + int fd, status = 0; > > + char f[sizeof "/proc/self/task//comm" + 7]; > > Where does 7 come from? I don't think it's correct. 3*sizeof(int) is > the normal lazy bound we use for %d's. man 5 proc says that the maximum value for a pid is about 4 million. I'm fine with to changing it to the usual lazy bound, though. > > + ssize_t len; > > + > > + if ((len = strlen(name)) > 15) return ERANGE; > > Storing the result of strlen in a ssize_t is odd. It works because no > object can be larger than SIZE_MAX/2, but it's ugly. Also using > strnlen would be preferable if there's a limit (so as not to read > unboundedly long strings only to reject them). ssize_t is a remnant from reusing len for the return value of write(). Will fix both issues. > > + > > + snprintf(f, sizeof f, "/proc/self/task/%d/comm", thread->tid); > > + if ((fd = open(f, O_WRONLY)) < 0) return errno; > > + if (write(fd, name, len) < 0) status = errno; > > + > > + close(fd); > > This needs blocking of the cancellation points, I think. Will look into it. Thanks, Felix