1 /*
2 * Copyright 2020 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 #include "os/fuzz/fake_timerfd.h"
18
19 #include <sys/eventfd.h>
20 #include <unistd.h>
21
22 #include <map>
23
24 namespace bluetooth {
25 namespace os {
26 namespace fuzz {
27
28 class FakeTimerFd {
29 public:
30 int fd;
31 bool active;
32 uint64_t trigger_ms;
33 uint64_t period_ms;
34 };
35
36 static std::map<int, FakeTimerFd*> fake_timers;
37 static uint64_t clock = 0;
38 static uint64_t max_clock = UINT64_MAX;
39
timespec_to_ms(const timespec * t)40 static uint64_t timespec_to_ms(const timespec* t) {
41 return t->tv_sec * 1000 + t->tv_nsec / 1000000;
42 }
43
fake_timerfd_create(int clockid,int flags)44 int fake_timerfd_create(int clockid, int flags) {
45 int fd = eventfd(0, 0);
46 if (fd == -1) {
47 return fd;
48 }
49
50 FakeTimerFd* entry = new FakeTimerFd();
51 fake_timers[fd] = entry;
52 entry->fd = fd;
53 return fd;
54 }
55
fake_timerfd_settime(int fd,int flags,const struct itimerspec * new_value,struct itimerspec * old_value)56 int fake_timerfd_settime(int fd, int flags, const struct itimerspec* new_value, struct itimerspec* old_value) {
57 if (fake_timers.find(fd) == fake_timers.end()) {
58 return -1;
59 }
60
61 FakeTimerFd* entry = fake_timers[fd];
62
63 uint64_t trigger_delta_ms = timespec_to_ms(&new_value->it_value);
64 entry->active = trigger_delta_ms != 0;
65 if (!entry->active) {
66 return 0;
67 }
68
69 uint64_t period_ms = timespec_to_ms(&new_value->it_value);
70 entry->trigger_ms = clock + trigger_delta_ms;
71 entry->period_ms = period_ms;
72 return 0;
73 }
74
fake_timerfd_close(int fd)75 int fake_timerfd_close(int fd) {
76 auto timer_iterator = fake_timers.find(fd);
77 if (timer_iterator != fake_timers.end()) {
78 delete timer_iterator->second;
79 fake_timers.erase(timer_iterator);
80 }
81 return close(fd);
82 }
83
fake_timerfd_reset()84 void fake_timerfd_reset() {
85 clock = 0;
86 max_clock = UINT64_MAX;
87 // if there are entries still here, it is a failure of our users to clean up
88 // so let them leak and trigger errors
89 fake_timers.clear();
90 }
91
fire_next_event(uint64_t new_clock)92 static bool fire_next_event(uint64_t new_clock) {
93 uint64_t earliest_time = new_clock;
94 FakeTimerFd* to_fire = nullptr;
95 for (auto it = fake_timers.begin(); it != fake_timers.end(); it++) {
96 FakeTimerFd* entry = it->second;
97 if (!entry->active) {
98 continue;
99 }
100
101 if (entry->trigger_ms > clock && entry->trigger_ms <= new_clock) {
102 if (to_fire == nullptr || entry->trigger_ms < earliest_time) {
103 to_fire = entry;
104 earliest_time = entry->trigger_ms;
105 }
106 }
107 }
108
109 if (to_fire == nullptr) {
110 return false;
111 }
112
113 bool is_periodic = to_fire->period_ms != 0;
114 if (is_periodic) {
115 to_fire->trigger_ms += to_fire->period_ms;
116 }
117 to_fire->active = is_periodic;
118 uint64_t value = 1;
119 write(to_fire->fd, &value, sizeof(uint64_t));
120 return true;
121 }
122
fake_timerfd_advance(uint64_t ms)123 void fake_timerfd_advance(uint64_t ms) {
124 uint64_t new_clock = clock + ms;
125 if (new_clock > max_clock) {
126 new_clock = max_clock;
127 }
128 while (fire_next_event(new_clock)) {
129 }
130 clock = new_clock;
131 }
132
fake_timerfd_cap_at(uint64_t ms)133 void fake_timerfd_cap_at(uint64_t ms) {
134 max_clock = ms;
135 }
136
137 } // namespace fuzz
138 } // namespace os
139 } // namespace bluetooth
140