1 /* Copyright (C) 1994-2021 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3
4 The GNU C Library is free software; you can redistribute it and/or
5 modify it under the terms of the GNU Lesser General Public
6 License as published by the Free Software Foundation; either
7 version 2.1 of the License, or (at your option) any later version.
8
9 The GNU C Library is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 Lesser General Public License for more details.
13
14 You should have received a copy of the GNU Lesser General Public
15 License along with the GNU C Library; if not, see
16 <https://www.gnu.org/licenses/>. */
17
18 #include <stddef.h>
19 #include <errno.h>
20 #include <sys/time.h>
21 #include <hurd.h>
22 #include <mach.h>
23
24 /* XXX Temporary cheezoid implementation; see setitimer.c. */
25
26 /* These are defined in __setitmr.c. */
27 extern spin_lock_t _hurd_itimer_lock;
28 extern struct itimerval _hurd_itimerval;
29 extern struct timeval _hurd_itimer_started;
30
31 static inline void
subtract_timeval(struct timeval * from,const struct timeval * subtract)32 subtract_timeval (struct timeval *from, const struct timeval *subtract)
33 {
34 from->tv_usec -= subtract->tv_usec;
35 from->tv_sec -= subtract->tv_sec;
36 while (from->tv_usec < 0)
37 {
38 --from->tv_sec;
39 from->tv_usec += 1000000;
40 }
41 }
42
43 /* Set *VALUE to the current setting of timer WHICH.
44 Return 0 on success, -1 on errors. */
45 int
__getitimer(enum __itimer_which which,struct itimerval * value)46 __getitimer (enum __itimer_which which, struct itimerval *value)
47 {
48 struct itimerval val;
49 struct timeval elapsed;
50
51 switch (which)
52 {
53 default:
54 return __hurd_fail (EINVAL);
55
56 case ITIMER_VIRTUAL:
57 case ITIMER_PROF:
58 return __hurd_fail (ENOSYS);
59
60 case ITIMER_REAL:
61 break;
62 }
63
64 /* Get the time now. */
65 {
66 time_value_t tv;
67 __host_get_time (__mach_host_self (), &tv);
68 elapsed.tv_sec = tv.seconds;
69 elapsed.tv_usec = tv.microseconds;
70 }
71
72 /* Extract the current timer setting; and the time it was set, so we can
73 calculate the time elapsed so far. */
74 HURD_CRITICAL_BEGIN;
75 __spin_lock (&_hurd_itimer_lock);
76 val = _hurd_itimerval;
77 subtract_timeval (&elapsed, &_hurd_itimer_started);
78 __spin_unlock (&_hurd_itimer_lock);
79 HURD_CRITICAL_END;
80
81 if ((val.it_value.tv_sec | val.it_value.tv_usec) != 0)
82 {
83 /* There is a pending alarm set. VAL indicates the interval it was
84 set for, relative to the time recorded in _hurd_itimer_started.
85 Now compensate for the time elapsed since to get the user's
86 conception of the current value of the timer (as if the value
87 stored decreased every microsecond). */
88 if (timercmp (&val.it_value, &elapsed, <))
89 {
90 /* Hmm. The timer should have just gone off, but has not been
91 reset. This is a possible timing glitch. The alarm will signal
92 soon, so fabricate a value for how soon. */
93 val.it_value.tv_sec = 0;
94 val.it_value.tv_usec = 10; /* Random. */
95 }
96 else
97 /* Subtract the time elapsed since the timer was set
98 from the current timer value the user sees. */
99 subtract_timeval (&val.it_value, &elapsed);
100 }
101
102 *value = val;
103 return 0;
104 }
105
106 weak_alias (__getitimer, getitimer)
107