1 /*
2 * Copyright (C) 2019 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 #define TRACE_TAG FDEVENT
18
19 #include "sysdeps.h"
20 #include "fdevent_poll.h"
21
22 #include <fcntl.h>
23 #include <inttypes.h>
24 #include <stdint.h>
25 #include <stdlib.h>
26 #include <string.h>
27 #include <unistd.h>
28
29 #include <atomic>
30 #include <deque>
31 #include <functional>
32 #include <list>
33 #include <mutex>
34 #include <optional>
35 #include <unordered_map>
36 #include <utility>
37 #include <variant>
38 #include <vector>
39
40 #include <android-base/chrono_utils.h>
41 #include <android-base/file.h>
42 #include <android-base/logging.h>
43 #include <android-base/stringprintf.h>
44 #include <android-base/threads.h>
45
46 #include "adb_io.h"
47 #include "adb_trace.h"
48 #include "adb_unique_fd.h"
49 #include "adb_utils.h"
50 #include "fdevent.h"
51 #include "sysdeps/chrono.h"
52
fdevent_interrupt(int fd,unsigned,void *)53 static void fdevent_interrupt(int fd, unsigned, void*) {
54 char buf[BUFSIZ];
55 ssize_t rc = TEMP_FAILURE_RETRY(adb_read(fd, buf, sizeof(buf)));
56 if (rc == -1) {
57 PLOG(FATAL) << "failed to read from fdevent interrupt fd";
58 }
59 }
60
fdevent_context_poll()61 fdevent_context_poll::fdevent_context_poll() {
62 int s[2];
63 if (adb_socketpair(s) != 0) {
64 PLOG(FATAL) << "failed to create fdevent interrupt socketpair";
65 }
66
67 if (!set_file_block_mode(s[0], false) || !set_file_block_mode(s[1], false)) {
68 PLOG(FATAL) << "failed to make fdevent interrupt socket nonblocking";
69 }
70
71 this->interrupt_fd_.reset(s[0]);
72 fdevent* fde = this->Create(unique_fd(s[1]), fdevent_interrupt, nullptr);
73 CHECK(fde != nullptr);
74 this->Add(fde, FDE_READ);
75 }
76
~fdevent_context_poll()77 fdevent_context_poll::~fdevent_context_poll() {
78 // Destroy calls virtual methods, but this class is final, so that's okay.
79 this->Destroy(this->interrupt_fde_);
80 }
81
Set(fdevent * fde,unsigned events)82 void fdevent_context_poll::Set(fdevent* fde, unsigned events) {
83 CheckMainThread();
84 fde->state = events;
85 D("fdevent_set: %s, events = %u", dump_fde(fde).c_str(), events);
86 }
87
dump_pollfds(const std::vector<adb_pollfd> & pollfds)88 static std::string dump_pollfds(const std::vector<adb_pollfd>& pollfds) {
89 std::string result;
90 for (const auto& pollfd : pollfds) {
91 std::string op;
92 if (pollfd.events & POLLIN) {
93 op += "R";
94 }
95 if (pollfd.events & POLLOUT) {
96 op += "W";
97 }
98 android::base::StringAppendF(&result, " %d(%s)", pollfd.fd, op.c_str());
99 }
100 return result;
101 }
102
Loop()103 void fdevent_context_poll::Loop() {
104 main_thread_id_ = android::base::GetThreadId();
105
106 std::vector<adb_pollfd> pollfds;
107 std::vector<fdevent_event> poll_events;
108
109 while (true) {
110 if (terminate_loop_) {
111 break;
112 }
113
114 D("--- --- waiting for events");
115 pollfds.clear();
116 for (const auto& [fd, fde] : this->installed_fdevents_) {
117 adb_pollfd pfd;
118 pfd.fd = fd;
119 pfd.events = 0;
120 if (fde.state & FDE_READ) {
121 pfd.events |= POLLIN;
122 }
123 if (fde.state & FDE_WRITE) {
124 pfd.events |= POLLOUT;
125 }
126 if (fde.state & FDE_ERROR) {
127 pfd.events |= POLLERR;
128 }
129 #if defined(__linux__)
130 pfd.events |= POLLRDHUP;
131 #endif
132 pfd.revents = 0;
133 pollfds.push_back(pfd);
134 }
135 CHECK_GT(pollfds.size(), 0u);
136 D("poll(), pollfds = %s", dump_pollfds(pollfds).c_str());
137
138 std::optional<std::chrono::milliseconds> timeout = CalculatePollDuration();
139 int timeout_ms;
140 if (!timeout) {
141 timeout_ms = -1;
142 } else {
143 timeout_ms = timeout->count();
144 }
145
146 int ret = adb_poll(pollfds.data(), pollfds.size(), timeout_ms);
147 if (ret == -1) {
148 PLOG(ERROR) << "poll(), ret = " << ret;
149 return;
150 }
151
152 auto post_poll = std::chrono::steady_clock::now();
153
154 for (const auto& pollfd : pollfds) {
155 unsigned events = 0;
156 if (pollfd.revents & POLLIN) {
157 events |= FDE_READ;
158 }
159 if (pollfd.revents & POLLOUT) {
160 events |= FDE_WRITE;
161 }
162 if (pollfd.revents & (POLLERR | POLLHUP | POLLNVAL)) {
163 // We fake a read, as the rest of the code assumes that errors will
164 // be detected at that point.
165 events |= FDE_READ | FDE_ERROR;
166 }
167 #if defined(__linux__)
168 if (pollfd.revents & POLLRDHUP) {
169 events |= FDE_READ | FDE_ERROR;
170 }
171 #endif
172
173 auto it = this->installed_fdevents_.find(pollfd.fd);
174 CHECK(it != this->installed_fdevents_.end());
175 fdevent* fde = &it->second;
176
177 if (events == 0) {
178 if (fde->timeout) {
179 auto deadline = fde->last_active + *fde->timeout;
180 if (deadline < post_poll) {
181 events |= FDE_TIMEOUT;
182 }
183 }
184 }
185
186 if (events != 0) {
187 D("%s got events %x", dump_fde(fde).c_str(), events);
188 poll_events.push_back({fde, events});
189 fde->last_active = post_poll;
190 }
191 }
192 this->HandleEvents(poll_events);
193 poll_events.clear();
194 }
195
196 main_thread_id_.reset();
197 }
198
InstalledCount()199 size_t fdevent_context_poll::InstalledCount() {
200 // We always have an installed fde for interrupt.
201 return this->installed_fdevents_.size() - 1;
202 }
203
Interrupt()204 void fdevent_context_poll::Interrupt() {
205 int rc = adb_write(this->interrupt_fd_, "", 1);
206
207 // It's possible that we get EAGAIN here, if lots of notifications came in while handling.
208 if (rc == 0) {
209 PLOG(FATAL) << "fdevent interrupt fd was closed?";
210 } else if (rc == -1 && errno != EAGAIN) {
211 PLOG(FATAL) << "failed to write to fdevent interrupt fd";
212 }
213 }
214
Register(fdevent *)215 void fdevent_context_poll::Register(fdevent*) {}
216
Unregister(fdevent *)217 void fdevent_context_poll::Unregister(fdevent*) {}
218