From mboxrd@z Thu Jan 1 00:00:00 1970 X-Msuck: nntp://news.gmane.org/gmane.linux.lib.musl.general/5985 Path: news.gmane.org!not-for-mail From: Jens Gustedt Newsgroups: gmane.linux.lib.musl.general Subject: [PATCH 2/8] additions to src/time Date: Sat, 30 Aug 2014 20:46:35 +0200 Message-ID: References: Reply-To: musl@lists.openwall.com NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Transfer-Encoding: 7bit X-Trace: ger.gmane.org 1409424409 5737 80.91.229.3 (30 Aug 2014 18:46:49 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Sat, 30 Aug 2014 18:46:49 +0000 (UTC) To: musl@lists.openwall.com Original-X-From: musl-return-5992-gllmg-musl=m.gmane.org@lists.openwall.com Sat Aug 30 20:46:45 2014 Return-path: Envelope-to: gllmg-musl@plane.gmane.org Original-Received: from mother.openwall.net ([195.42.179.200]) by plane.gmane.org with smtp (Exim 4.69) (envelope-from ) id 1XNnfg-0000DD-Uw for gllmg-musl@plane.gmane.org; Sat, 30 Aug 2014 20:46:45 +0200 Original-Received: (qmail 3465 invoked by uid 550); 30 Aug 2014 18:46:44 -0000 Mailing-List: contact musl-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: Original-Received: (qmail 3457 invoked from network); 30 Aug 2014 18:46:44 -0000 X-IronPort-AV: E=Sophos;i="5.04,432,1406584800"; d="scan'208";a="92267755" In-Reply-To: Resent-From: Jens Gustedt Resent-To: musl@lists.openwall.com X-Mailer: Evolution 3.4.4-3 Xref: news.gmane.org gmane.linux.lib.musl.general:5985 Archived-At: This adds two functions, thrd_sleep and timespec_get. Both have easy functional equivalences in POSIX, but these have subtle differences in the handling of errors. thrd_sleep forces concrete numerical values as error return timespec_get has a call interface that is incompatible with POSIX because it has a bogus coding for its clock constants, and also this clock constants must be returned in case of success. For the moment we only implement one single clock, TIME_UTC, and map this to CLOCK_REALTIME. This is the clock that we later need to measure time for the timedlock and timedwait. Also, other than for clock_gettime, C doesn't specify touching errno for timespec_get. Because CLOCK_REALTIME can be obtained very efficiently through VDSO and messing with errno is clearly the wrong step to go, we try to avoid this. --- src/time/thrd_sleep.c | 26 ++++++++++++++++++++++++++ src/time/timespec_get.c | 31 +++++++++++++++++++++++++++++++ 2 files changed, 57 insertions(+) create mode 100644 src/time/thrd_sleep.c create mode 100644 src/time/timespec_get.c diff --git a/src/time/thrd_sleep.c b/src/time/thrd_sleep.c new file mode 100644 index 0000000..3dbfe47 --- /dev/null +++ b/src/time/thrd_sleep.c @@ -0,0 +1,26 @@ +#include +#include +#include "syscall.h" +#include "libc.h" +#include "threads.h" + +/* Roughly __syscall already returns the right thing: 0 if all went + well or a negative error indication, otherwise. */ +int thrd_sleep(const struct timespec *req, struct timespec *rem) +{ + int ret = __syscall(SYS_nanosleep, req, rem); + switch (ret) { + case 0: + return 0; + /* error described by POSIX: */ + /* EINTR The nanosleep() function was interrupted by a signal. */ + /* The C11 wording is: */ + /* -1 if it has been interrupted by a signal */ + case -EINTR: + return -1; + /* EINVAL: described by POSIX */ + /* EFAULT: described for linux */ + default: + return -2; + } +} diff --git a/src/time/timespec_get.c b/src/time/timespec_get.c new file mode 100644 index 0000000..20080a0 --- /dev/null +++ b/src/time/timespec_get.c @@ -0,0 +1,31 @@ +#include +#include "syscall.h" +#include "atomic.h" + +static int syscall_clock_gettime(clockid_t clk, struct timespec *ts) +{ + return __syscall(SYS_clock_gettime, clk, ts); +} + +void *__vdsosym(const char *, const char *); + +/* There is no other implemented value than TIME_UTC, all other values + are considered erroneous. */ +int timespec_get(struct timespec * ts, int base) +{ + if (base != TIME_UTC) return 0; + int ret; +#ifdef VDSO_CGT_SYM + static int (*cgt)(clockid_t, struct timespec *); + if (!cgt) { + void *f = __vdsosym(VDSO_CGT_VER, VDSO_CGT_SYM); + if (!f) f = (void *)syscall_clock_gettime; + a_cas_p(&cgt, 0, f); + } + /* The vdso variants never fail, and thus never set errno. */ + ret = cgt(CLOCK_REALTIME, ts); +#else + ret = syscall_clock_gettime(CLOCK_REALTIME, ts); +#endif + return ret < 0 ? 0 : base; +} -- 1.7.10.4