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platform_system_core/adb/fdevent.cpp

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/* http://frotznet.googlecode.com/svn/trunk/utils/fdevent.c
**
** Copyright 2006, Brian Swetland <swetland@frotz.net>
**
** Licensed under the Apache License, Version 2.0 (the "License");
** you may not use this file except in compliance with the License.
** You may obtain a copy of the License at
**
** http://www.apache.org/licenses/LICENSE-2.0
**
** Unless required by applicable law or agreed to in writing, software
** distributed under the License is distributed on an "AS IS" BASIS,
** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
** See the License for the specific language governing permissions and
** limitations under the License.
*/
#define TRACE_TAG FDEVENT
#include "sysdeps.h"
#include "fdevent.h"
#include <fcntl.h>
#include <poll.h>
#include <stdlib.h>
#include <string.h>
#include <sys/ioctl.h>
#include <unistd.h>
#include <list>
#include <unordered_map>
#include <vector>
#include <android-base/logging.h>
#include <android-base/stringprintf.h>
#include "adb_io.h"
#include "adb_trace.h"
#include "adb_utils.h"
#if !ADB_HOST
// This socket is used when a subproc shell service exists.
// It wakes up the fdevent_loop() and cause the correct handling
// of the shell's pseudo-tty master. I.e. force close it.
int SHELL_EXIT_NOTIFY_FD = -1;
#endif // !ADB_HOST
#define FDE_EVENTMASK 0x00ff
#define FDE_STATEMASK 0xff00
#define FDE_ACTIVE 0x0100
#define FDE_PENDING 0x0200
#define FDE_CREATED 0x0400
struct PollNode {
fdevent* fde;
::pollfd pollfd;
PollNode(fdevent* fde) : fde(fde) {
memset(&pollfd, 0, sizeof(pollfd));
pollfd.fd = fde->fd;
#if defined(__linux__)
// Always enable POLLRDHUP, so the host server can take action when some clients disconnect.
// Then we can avoid leaving many sockets in CLOSE_WAIT state. See http://b/23314034.
pollfd.events = POLLRDHUP;
#endif
}
};
// All operations to fdevent should happen only in the main thread.
// That's why we don't need a lock for fdevent.
static auto& g_poll_node_map = *new std::unordered_map<int, PollNode>();
static auto& g_pending_list = *new std::list<fdevent*>();
static bool main_thread_valid;
static pthread_t main_thread;
static void check_main_thread() {
if (main_thread_valid) {
CHECK_NE(0, pthread_equal(main_thread, pthread_self()));
}
}
static void set_main_thread() {
main_thread_valid = true;
main_thread = pthread_self();
}
static std::string dump_fde(const fdevent* fde) {
std::string state;
if (fde->state & FDE_ACTIVE) {
state += "A";
}
if (fde->state & FDE_PENDING) {
state += "P";
}
if (fde->state & FDE_CREATED) {
state += "C";
}
if (fde->state & FDE_READ) {
state += "R";
}
if (fde->state & FDE_WRITE) {
state += "W";
}
if (fde->state & FDE_ERROR) {
state += "E";
}
if (fde->state & FDE_DONT_CLOSE) {
state += "D";
}
return android::base::StringPrintf("(fdevent %d %s)", fde->fd, state.c_str());
}
fdevent *fdevent_create(int fd, fd_func func, void *arg)
{
check_main_thread();
fdevent *fde = (fdevent*) malloc(sizeof(fdevent));
if(fde == 0) return 0;
fdevent_install(fde, fd, func, arg);
fde->state |= FDE_CREATED;
return fde;
}
void fdevent_destroy(fdevent *fde)
{
check_main_thread();
if(fde == 0) return;
if(!(fde->state & FDE_CREATED)) {
LOG(FATAL) << "destroying fde not created by fdevent_create(): " << dump_fde(fde);
}
fdevent_remove(fde);
free(fde);
}
void fdevent_install(fdevent* fde, int fd, fd_func func, void* arg) {
check_main_thread();
CHECK_GE(fd, 0);
memset(fde, 0, sizeof(fdevent));
fde->state = FDE_ACTIVE;
fde->fd = fd;
fde->func = func;
fde->arg = arg;
if (!set_file_block_mode(fd, false)) {
// Here is not proper to handle the error. If it fails here, some error is
// likely to be detected by poll(), then we can let the callback function
// to handle it.
LOG(ERROR) << "failed to set non-blocking mode for fd " << fd;
}
auto pair = g_poll_node_map.emplace(fde->fd, PollNode(fde));
CHECK(pair.second) << "install existing fd " << fd;
D("fdevent_install %s", dump_fde(fde).c_str());
}
void fdevent_remove(fdevent* fde) {
check_main_thread();
D("fdevent_remove %s", dump_fde(fde).c_str());
if (fde->state & FDE_ACTIVE) {
g_poll_node_map.erase(fde->fd);
if (fde->state & FDE_PENDING) {
g_pending_list.remove(fde);
}
if (!(fde->state & FDE_DONT_CLOSE)) {
adb_close(fde->fd);
fde->fd = -1;
}
fde->state = 0;
fde->events = 0;
}
}
static void fdevent_update(fdevent* fde, unsigned events) {
auto it = g_poll_node_map.find(fde->fd);
CHECK(it != g_poll_node_map.end());
PollNode& node = it->second;
if (events & FDE_READ) {
node.pollfd.events |= POLLIN;
} else {
node.pollfd.events &= ~POLLIN;
}
if (events & FDE_WRITE) {
node.pollfd.events |= POLLOUT;
} else {
node.pollfd.events &= ~POLLOUT;
}
fde->state = (fde->state & FDE_STATEMASK) | events;
}
void fdevent_set(fdevent* fde, unsigned events) {
check_main_thread();
events &= FDE_EVENTMASK;
if ((fde->state & FDE_EVENTMASK) == events) {
return;
}
CHECK(fde->state & FDE_ACTIVE);
fdevent_update(fde, events);
D("fdevent_set: %s, events = %u", dump_fde(fde).c_str(), events);
if (fde->state & FDE_PENDING) {
// If we are pending, make sure we don't signal an event that is no longer wanted.
fde->events &= events;
if (fde->events == 0) {
g_pending_list.remove(fde);
fde->state &= ~FDE_PENDING;
}
}
}
void fdevent_add(fdevent* fde, unsigned events) {
check_main_thread();
fdevent_set(fde, (fde->state & FDE_EVENTMASK) | events);
}
void fdevent_del(fdevent* fde, unsigned events) {
check_main_thread();
fdevent_set(fde, (fde->state & FDE_EVENTMASK) & ~events);
}
static std::string dump_pollfds(const std::vector<pollfd>& pollfds) {
std::string result;
for (const auto& pollfd : pollfds) {
std::string op;
if (pollfd.events & POLLIN) {
op += "R";
}
if (pollfd.events & POLLOUT) {
op += "W";
}
android::base::StringAppendF(&result, " %d(%s)", pollfd.fd, op.c_str());
}
return result;
}
static void fdevent_process() {
std::vector<pollfd> pollfds;
for (const auto& pair : g_poll_node_map) {
pollfds.push_back(pair.second.pollfd);
}
CHECK_GT(pollfds.size(), 0u);
D("poll(), pollfds = %s", dump_pollfds(pollfds).c_str());
int ret = TEMP_FAILURE_RETRY(poll(&pollfds[0], pollfds.size(), -1));
if (ret == -1) {
PLOG(ERROR) << "poll(), ret = " << ret;
return;
}
for (const auto& pollfd : pollfds) {
if (pollfd.revents != 0) {
D("for fd %d, revents = %x", pollfd.fd, pollfd.revents);
}
unsigned events = 0;
if (pollfd.revents & POLLIN) {
events |= FDE_READ;
}
if (pollfd.revents & POLLOUT) {
events |= FDE_WRITE;
}
if (pollfd.revents & (POLLERR | POLLHUP | POLLNVAL)) {
// We fake a read, as the rest of the code assumes that errors will
// be detected at that point.
events |= FDE_READ | FDE_ERROR;
}
#if defined(__linux__)
if (pollfd.revents & POLLRDHUP) {
events |= FDE_READ | FDE_ERROR;
}
#endif
if (events != 0) {
auto it = g_poll_node_map.find(pollfd.fd);
CHECK(it != g_poll_node_map.end());
fdevent* fde = it->second.fde;
CHECK_EQ(fde->fd, pollfd.fd);
fde->events |= events;
D("%s got events %x", dump_fde(fde).c_str(), events);
fde->state |= FDE_PENDING;
g_pending_list.push_back(fde);
}
}
}
static void fdevent_call_fdfunc(fdevent* fde)
{
unsigned events = fde->events;
fde->events = 0;
CHECK(fde->state & FDE_PENDING);
fde->state &= (~FDE_PENDING);
D("fdevent_call_fdfunc %s", dump_fde(fde).c_str());
fde->func(fde->fd, events, fde->arg);
}
#if !ADB_HOST
static void fdevent_subproc_event_func(int fd, unsigned ev,
void* /* userdata */)
{
D("subproc handling on fd = %d, ev = %x", fd, ev);
CHECK_GE(fd, 0);
if (ev & FDE_READ) {
int subproc_fd;
if(!ReadFdExactly(fd, &subproc_fd, sizeof(subproc_fd))) {
LOG(FATAL) << "Failed to read the subproc's fd from " << fd;
}
auto it = g_poll_node_map.find(subproc_fd);
if (it == g_poll_node_map.end()) {
D("subproc_fd %d cleared from fd_table", subproc_fd);
return;
}
fdevent* subproc_fde = it->second.fde;
if(subproc_fde->fd != subproc_fd) {
// Already reallocated?
D("subproc_fd(%d) != subproc_fde->fd(%d)", subproc_fd, subproc_fde->fd);
return;
}
subproc_fde->force_eof = 1;
int rcount = 0;
ioctl(subproc_fd, FIONREAD, &rcount);
D("subproc with fd %d has rcount=%d, err=%d", subproc_fd, rcount, errno);
if (rcount != 0) {
// If there is data left, it will show up in the select().
// This works because there is no other thread reading that
// data when in this fd_func().
return;
}
D("subproc_fde %s", dump_fde(subproc_fde).c_str());
subproc_fde->events |= FDE_READ;
if(subproc_fde->state & FDE_PENDING) {
return;
}
subproc_fde->state |= FDE_PENDING;
fdevent_call_fdfunc(subproc_fde);
}
}
void fdevent_subproc_setup()
{
int s[2];
if(adb_socketpair(s)) {
PLOG(FATAL) << "cannot create shell-exit socket-pair";
}
D("fdevent_subproc: socket pair (%d, %d)", s[0], s[1]);
SHELL_EXIT_NOTIFY_FD = s[0];
fdevent *fde = fdevent_create(s[1], fdevent_subproc_event_func, NULL);
CHECK(fde != nullptr) << "cannot create fdevent for shell-exit handler";
fdevent_add(fde, FDE_READ);
}
#endif // !ADB_HOST
void fdevent_loop()
{
set_main_thread();
#if !ADB_HOST
fdevent_subproc_setup();
#endif // !ADB_HOST
while (true) {
D("--- --- waiting for events");
fdevent_process();
while (!g_pending_list.empty()) {
fdevent* fde = g_pending_list.front();
g_pending_list.pop_front();
fdevent_call_fdfunc(fde);
}
}
}
size_t fdevent_installed_count() {
return g_poll_node_map.size();
}
void fdevent_reset() {
g_poll_node_map.clear();
g_pending_list.clear();
main_thread_valid = false;
}
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