1/* clock_nanosleep - high-resolution sleep with specifiable clock.
2 Copyright (C) 2002-2022 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <https://www.gnu.org/licenses/>. */
18
19#include <errno.h>
20#include <mach.h>
21#include <time.h>
22#include <unistd.h>
23#include <posix-timer.h>
24#include <shlib-compat.h>
25#include <sysdep-cancel.h>
26
27static int
28nanosleep_call (const struct timespec *req, struct timespec *rem)
29{
30 mach_port_t recv;
31 struct timespec before;
32 error_t err;
33
34 const mach_msg_timeout_t ms
35 = req->tv_sec * 1000
36 + (req->tv_nsec + 999999) / 1000000;
37
38 recv = __mach_reply_port ();
39
40 if (rem != NULL)
41 __clock_gettime (CLOCK_REALTIME, &before);
42
43 int cancel_oldtype = LIBC_CANCEL_ASYNC();
44 err = __mach_msg (NULL, MACH_RCV_MSG|MACH_RCV_TIMEOUT|MACH_RCV_INTERRUPT,
45 0, 0, recv, ms, MACH_PORT_NULL);
46 LIBC_CANCEL_RESET (cancel_oldtype);
47
48 __mach_port_destroy (mach_task_self (), recv);
49
50 if (err == EMACH_RCV_INTERRUPTED)
51 {
52 if (rem != NULL)
53 {
54 struct timespec after, elapsed;
55 __clock_gettime (CLOCK_REALTIME, &after);
56 timespec_sub (diff: &elapsed, left: &after, right: &before);
57 timespec_sub (diff: rem, left: req, right: &elapsed);
58 }
59
60 return EINTR;
61 }
62
63 return 0;
64}
65
66int
67__clock_nanosleep (clockid_t clock_id, int flags, const struct timespec *req,
68 struct timespec *rem)
69{
70 if (clock_id != CLOCK_REALTIME
71 || !valid_nanoseconds (ns: req->tv_nsec)
72 || (flags != 0 && flags != TIMER_ABSTIME))
73 return EINVAL;
74
75 struct timespec now;
76
77 /* If we got an absolute time, remap it. */
78 if (flags == TIMER_ABSTIME)
79 {
80 long int nsec;
81 long int sec;
82
83 /* Make sure we use safe data types. */
84 assert (sizeof (sec) >= sizeof (now.tv_sec));
85
86 /* Get the current time for this clock. */
87 if (__clock_gettime (clock_id, &now) != 0)
88 return errno;
89
90 /* Compute the difference. */
91 nsec = req->tv_nsec - now.tv_nsec;
92 sec = req->tv_sec - now.tv_sec - (nsec < 0);
93 if (sec < 0)
94 /* The time has already elapsed. */
95 return 0;
96
97 now.tv_sec = sec;
98 now.tv_nsec = nsec + (nsec < 0 ? 1000000000 : 0);
99
100 /* From now on this is our time. */
101 req = &now;
102
103 /* Make sure we are not modifying the struct pointed to by REM. */
104 rem = NULL;
105 }
106
107 return nanosleep_call (req, rem);
108}
109libc_hidden_def (__clock_nanosleep)
110versioned_symbol (libc, __clock_nanosleep, clock_nanosleep, GLIBC_2_17);
111/* clock_nanosleep moved to libc in version 2.17;
112 old binaries may expect the symbol version it had in librt. */
113#if SHLIB_COMPAT (libc, GLIBC_2_2, GLIBC_2_17)
114strong_alias (__clock_nanosleep, __clock_nanosleep_2);
115compat_symbol (libc, __clock_nanosleep_2, clock_nanosleep, GLIBC_2_2);
116#endif
117

source code of glibc/sysdeps/mach/clock_nanosleep.c