1 /*
2 * Copyright 2022-2025 The OpenSSL Project Authors. All Rights Reserved.
3 *
4 * Licensed under the Apache License 2.0 (the "License"). You may not use
5 * this file except in compliance with the License. You can obtain a copy
6 * in the file LICENSE in the source distribution or at
7 * https://www.openssl.org/source/license.html
8 */
9
10 #include <openssl/crypto.h>
11 #include "internal/e_os.h"
12 #include "internal/time.h"
13
14 /* system-specific variants defining OSSL_sleep() */
15 #if (defined(OPENSSL_SYS_UNIX) || defined(__DJGPP__)) && !defined(OPENSSL_USE_SLEEP_BUSYLOOP)
16
17 # if defined(OPENSSL_USE_USLEEP) \
18 || defined(__DJGPP__) \
19 || (defined(__TANDEM) && defined(_REENTRANT))
20
21 /*
22 * usleep() was made obsolete by POSIX.1-2008, and nanosleep()
23 * should be used instead. However, nanosleep() isn't implemented
24 * on the platforms given above, so we still use it for those.
25 * Also, OPENSSL_USE_USLEEP can be defined to enable the use of
26 * usleep, if it turns out that nanosleep() is unavailable.
27 */
28
29 # include <unistd.h>
ossl_sleep_millis(uint64_t millis)30 static void ossl_sleep_millis(uint64_t millis)
31 {
32 unsigned int s = (unsigned int)(millis / 1000);
33 unsigned int us = (unsigned int)((millis % 1000) * 1000);
34
35 if (s > 0)
36 sleep(s);
37 /*
38 * On NonStop with the PUT thread model, thread context switch is
39 * cooperative, with usleep() being a "natural" context switch point.
40 * We avoid checking us > 0 here, to allow that context switch to
41 * happen.
42 */
43 usleep(us);
44 }
45
46 # elif defined(__TANDEM) && !defined(_REENTRANT)
47
48 # include <cextdecs.h(PROCESS_DELAY_)>
ossl_sleep_millis(uint64_t millis)49 static void ossl_sleep_millis(uint64_t millis)
50 {
51 /* HPNS does not support usleep for non threaded apps */
52 PROCESS_DELAY_(millis * 1000);
53 }
54
55 # else
56
57 /* nanosleep is defined by POSIX.1-2001 */
58 # include <time.h>
ossl_sleep_millis(uint64_t millis)59 static void ossl_sleep_millis(uint64_t millis)
60 {
61 struct timespec ts;
62
63 ts.tv_sec = (long int) (millis / 1000);
64 ts.tv_nsec = (long int) (millis % 1000) * 1000000ul;
65 nanosleep(&ts, NULL);
66 }
67
68 # endif
69 #elif defined(_WIN32) && !defined(OPENSSL_SYS_UEFI)
70 # include <windows.h>
71
ossl_sleep_millis(uint64_t millis)72 static void ossl_sleep_millis(uint64_t millis)
73 {
74 /*
75 * Windows' Sleep() takes a DWORD argument, which is smaller than
76 * a uint64_t, so we need to limit it to 49 days, which should be enough.
77 */
78 DWORD limited_millis = (DWORD)-1;
79
80 if (millis < limited_millis)
81 limited_millis = (DWORD)millis;
82 Sleep(limited_millis);
83 }
84
85 #else
86 /* Fallback to a busy wait */
87 # define USE_SLEEP_SECS
88
ossl_sleep_secs(uint64_t secs)89 static void ossl_sleep_secs(uint64_t secs)
90 {
91 /*
92 * sleep() takes an unsigned int argument, which is smaller than
93 * a uint64_t, so it needs to be limited to 136 years which
94 * should be enough even for Sleeping Beauty.
95 */
96 unsigned int limited_secs = UINT_MAX;
97
98 if (secs < limited_secs)
99 limited_secs = (unsigned int)secs;
100 sleep(limited_secs);
101 }
102
ossl_sleep_millis(uint64_t millis)103 static void ossl_sleep_millis(uint64_t millis)
104 {
105 const OSSL_TIME finish
106 = ossl_time_add(ossl_time_now(), ossl_ms2time(millis));
107
108 while (ossl_time_compare(ossl_time_now(), finish) < 0)
109 /* busy wait */ ;
110 }
111 #endif /* defined(OPENSSL_SYS_UNIX) || defined(__DJGPP__) */
112
OSSL_sleep(uint64_t millis)113 void OSSL_sleep(uint64_t millis)
114 {
115 OSSL_TIME now = ossl_time_now();
116 OSSL_TIME finish = ossl_time_add(now, ossl_ms2time(millis));
117 uint64_t left = millis;
118
119 #if defined(USE_SLEEP_SECS)
120 do {
121 ossl_sleep_secs(left / 1000);
122 now = ossl_time_now();
123 left = ossl_time2ms(ossl_time_subtract(finish, now));
124 } while (ossl_time_compare(now, finish) < 0 && left > 1000);
125
126 if (ossl_time_compare(now, finish) >= 0)
127 return;
128 #endif
129
130 do {
131 ossl_sleep_millis(left);
132 now = ossl_time_now();
133 left = ossl_time2ms(ossl_time_subtract(finish, now));
134 } while (ossl_time_compare(now, finish) < 0);
135 }
136