[vlc-devel] [PATCH] compat: add clock_gettime, clock_nanosleep for darwin
Marvin Scholz
epirat07 at gmail.com
Thu Feb 27 15:56:01 CET 2020
---
compat/clock_gettime.c | 131 +++++++++++++++++++++++++++++++++++++++
compat/clock_nanosleep.c | 108 ++++++++++++++++++++++++++++++++
configure.ac | 6 ++
include/vlc_fixups.h | 18 ++++++
4 files changed, 263 insertions(+)
create mode 100644 compat/clock_gettime.c
create mode 100644 compat/clock_nanosleep.c
diff --git a/compat/clock_gettime.c b/compat/clock_gettime.c
new file mode 100644
index 0000000000..fb3312fd2d
--- /dev/null
+++ b/compat/clock_gettime.c
@@ -0,0 +1,131 @@
+/*****************************************************************************
+ * clock_gettime.c: POSIX clock_gettime() replacement
+ *****************************************************************************
+ * Copyright © 2020 VLC authors and VideoLAN
+ *
+ * Author: Marvin Scholz <epirat07 at gmail dot com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation; either version 2.1 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
+ *****************************************************************************/
+
+#ifndef __APPLE__
+# error clock_gettime not implemented on your platform!
+#endif
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+
+#define _DARWIN_C_SOURCE
+#define _POSIX_C_SOURCE 200809L
+
+#include <sys/errno.h>
+#include <sys/types.h>
+#include <sys/time.h>
+#include <sys/sysctl.h>
+#include <time.h>
+
+/**
+ * Get the absolute time at which the system was booted
+ *
+ * This time is changed whenever the clock is adjusted to
+ * correctly reflect the boot time with the adjusted clock,
+ * so just querying it once and reusing the value is not safe.
+ *
+ * \param[out] tv Timeval struct to write the boottime to
+ *
+ * \note
+ * The boot time only has microsecond precision
+ *
+ * \return 0 on success, else -1 and errno set
+ */
+static inline int vlc__get_system_boottime(struct timeval *tv)
+{
+ int ret = sysctl((int[]){ CTL_KERN, KERN_BOOTTIME }, 2,
+ tv, &(size_t){ sizeof(*tv) }, NULL, 0);
+
+ if (ret != 0)
+ return errno;
+
+ return 0;
+}
+
+/**
+ * Get the monotonic time (CLOCK_MONOTONIC)
+ *
+ * Calculates a monotically incrasing time since system boot
+ * that continues to increment when the syste is asleep.
+ *
+ * Warnings to everyone trying to simplify this:
+ * - Using mach_continuous_time is not equivalent to this, see
+ * the darwin manpage about CLOCK_MONOTONIC_RAW for an explanation.
+ * - Using mach_absolute_time is not equivalent to this, as it does
+ * not continue to increment when the system is asleep.
+ * - The boot time is queried twice in a loop and only used if both
+ * match. This is done to detect if the boot time change since we
+ * obtained the current time of day, as the boot time can change
+ * when the system wallclock is adjusted, as that will adjust the
+ * boot time accordingly.
+ *
+ * \param[out] tv Timeval struct to write the monotonic time to
+ *
+ * \return 0 on success, else -1 and errno set
+ */
+static int vlc__get_monotonic(struct timeval *tv)
+{
+ int ret;
+ struct timeval currenttime;
+ struct timeval boottime_begin;
+ struct timeval boottime_end;
+
+ do {
+ ret = vlc__get_system_boottime(&boottime_begin);
+ if (ret != 0)
+ return ret;
+
+ ret = gettimeofday(¤ttime, NULL);
+ if (ret != 0)
+ return ret;
+
+ ret = vlc__get_system_boottime(&boottime_end);
+ if (ret != 0)
+ return ret;
+ } while (timercmp(&boottime_begin, &boottime_end, !=));
+
+ timersub(¤ttime, &boottime_begin, tv);
+ return 0;
+}
+
+int clock_gettime(clockid_t clock_id, struct timespec *tp)
+{
+ int ret = 0;
+ struct timeval tv;
+
+ switch (clock_id) {
+ case CLOCK_MONOTONIC:
+ ret = vlc__get_monotonic(&tv);
+ break;
+ case CLOCK_REALTIME:
+ ret = gettimeofday(&tv, NULL);
+ break;
+ default:
+ errno = EINVAL;
+ return -1;
+ }
+
+ if (ret == 0)
+ TIMEVAL_TO_TIMESPEC(&tv, tp);
+ return ret;
+}
diff --git a/compat/clock_nanosleep.c b/compat/clock_nanosleep.c
new file mode 100644
index 0000000000..f5cab11039
--- /dev/null
+++ b/compat/clock_nanosleep.c
@@ -0,0 +1,108 @@
+/*****************************************************************************
+ * clock_nanosleep.c: POSIX clock_nanosleep() replacement
+ *****************************************************************************
+ * Copyright © 2020 VLC authors and VideoLAN
+ *
+ * Author: Marvin Scholz <epirat07 at gmail dot com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation; either version 2.1 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
+ *****************************************************************************/
+
+#ifndef __APPLE__
+# error clock_nanosleep not implemented on your platform!
+#endif
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+
+#define _DARWIN_C_SOURCE
+#define _POSIX_C_SOURCE 200809L
+
+#include <pthread.h>
+#include <sys/errno.h>
+#include <sys/types.h>
+#include <sys/time.h>
+#include <sys/sysctl.h>
+#include <mach/clock_types.h>
+
+#define timespecs_sub(tsa, tsb, tsr) \
+ do { \
+ (tsr)->tv_sec = (tsa)->tv_sec - (tsb)->tv_sec; \
+ (tsr)->tv_nsec = (tsa)->tv_nsec - (tsb)->tv_nsec; \
+ if ((tsr)->tv_nsec < 0) { \
+ (tsr)->tv_sec--; \
+ (tsr)->tv_nsec += NSEC_PER_SEC; \
+ } \
+ } while (0)
+
+#define timespec_zero(ts) \
+ ((ts)->tv_sec == 0 && (ts)->tv_nsec == 0)
+
+int clock_nanosleep(clockid_t clock_id, int flags,
+ const struct timespec *rqtp, struct timespec *rmtp)
+{
+ int err = EINVAL;
+ struct timespec ts_rel;
+
+ // Validate timespec
+ if (rqtp == NULL || rqtp->tv_sec < 0 ||
+ rqtp->tv_nsec < 0 || (unsigned long)rqtp->tv_nsec >= NSEC_PER_SEC)
+ goto error;
+
+ if (flags == TIMER_ABSTIME) {
+ struct timespec ts_now;
+
+ // We don't support waiting for a absolute
+ // wallclock time currently
+ if (clock_id == CLOCK_REALTIME) {
+ err = ENOTSUP;
+ goto error;
+ }
+
+ // Get current time with requested clock
+ if (clock_gettime(clock_id, &ts_now) != 0) {
+ err = errno;
+ goto error;
+ }
+
+ // Calculate relative timespec
+ timespecs_sub(rqtp, &ts_now, &ts_rel);
+
+ // Check if time already elapsed
+ if (ts_rel.tv_sec < 0 || timespec_zero(&ts_rel)) {
+ pthread_testcancel();
+ return 0;
+ }
+ } else if (flags == 0) {
+ ts_rel = *rqtp;
+ } else {
+ // Invalid flags
+ goto error;
+ }
+
+ switch (clock_id) {
+ case CLOCK_MONOTONIC:
+ case CLOCK_REALTIME:
+ return nanosleep(&ts_rel, rmtp);
+ default:
+ goto error;
+ }
+
+error:
+ pthread_testcancel();
+ errno = err;
+ return -1;
+}
diff --git a/configure.ac b/configure.ac
index bc1874cb97..c20ab3c75c 100644
--- a/configure.ac
+++ b/configure.ac
@@ -179,6 +179,12 @@ case "${host_os}" in
VLC_ADD_LIBS([libvlc vlc],[-Wl,-undefined,dynamic_lookup,-framework,AppKit])
VLC_ADD_LIBS([libvlccore],[-Wl,-framework,CoreFoundation,-framework,CoreServices])
+ dnl macOS 10.11 lacks clock_gettime, introduced with 10.12
+ AC_LIBOBJ([clock_gettime])
+ dnl macOS lacks clock_nanosleep
+ AC_LIBOBJ([clock_nanosleep])
+ AC_CHECK_FUNCS([clock_gettime clock_nanosleep])
+
AC_EGREP_CPP(yes,
[#import <TargetConditionals.h>
#if TARGET_OS_IPHONE
diff --git a/include/vlc_fixups.h b/include/vlc_fixups.h
index 8fd01da0ce..a296db0c32 100644
--- a/include/vlc_fixups.h
+++ b/include/vlc_fixups.h
@@ -658,6 +658,24 @@ FILE *vlc_win32_tmpfile(void);
#ifdef __APPLE__
# define fdatasync fsync
+
+# include <time.h>
+# ifndef TIMER_ABSTIME
+# define TIMER_ABSTIME 0x01
+# endif
+# ifndef CLOCK_REALTIME
+# define CLOCK_REALTIME 0
+# endif
+# ifndef CLOCK_MONOTONIC
+# define CLOCK_MONOTONIC 6
+# endif
+# ifndef HAVE_CLOCK_GETTIME
+int clock_gettime(clockid_t clock_id, struct timespec *tp);
+# endif
+# ifndef HAVE_CLOCK_NANOSLEEP
+int clock_nanosleep(clockid_t clock_id, int flags,
+ const struct timespec *rqtp, struct timespec *rmtp);
+# endif
#endif
#ifdef __cplusplus
--
2.21.1 (Apple Git-122.3)
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