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This commit is contained in:
Andrew Noyes
2025-08-18 15:50:50 -04:00
parent 368ec721d5
commit 5bc78577c6
2 changed files with 621 additions and 66 deletions
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136
src/main.cpp
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@@ -31,6 +31,7 @@ void signal_handler(int sig) {
if (sig == SIGTERM || sig == SIGINT) {
if (shutdown_eventfd != -1) {
uint64_t val = 1;
// write() is async-signal-safe per POSIX - safe to use in signal handler
if (write(shutdown_eventfd, &val, sizeof(val)) == -1) {
abort(); // Critical failure - can't signal shutdown
}
@@ -281,7 +282,11 @@ int main(int argc, char *argv[]) {
struct epoll_event shutdown_event;
shutdown_event.events = EPOLLIN;
shutdown_event.data.fd = shutdown_eventfd;
epoll_ctl(network_epollfd, EPOLL_CTL_ADD, shutdown_eventfd, &shutdown_event);
if (epoll_ctl(network_epollfd, EPOLL_CTL_ADD, shutdown_eventfd,
&shutdown_event) == -1) {
perror("epoll_ctl add shutdown event");
abort();
}
std::atomic<int64_t> connectionId{0};
@@ -289,73 +294,72 @@ int main(int argc, char *argv[]) {
int networkThreads = config->server.network_threads;
for (int i = 0; i < networkThreads; ++i) {
threads.emplace_back(
[network_epollfd, i,
max_request_size = config->server.max_request_size_bytes,
event_batch_size = config->server.event_batch_size]() {
pthread_setname_np(pthread_self(),
("network-" + std::to_string(i)).c_str());
std::vector<struct epoll_event> events(event_batch_size);
for (;;) {
int eventCount = epoll_wait(network_epollfd, events.data(),
event_batch_size, -1 /* no timeout */);
if (eventCount == -1) {
if (errno == EINTR) {
continue;
}
perror("epoll_wait");
abort();
}
threads.emplace_back([network_epollfd, i,
max_request_size =
config->server.max_request_size_bytes,
event_batch_size =
config->server.event_batch_size]() {
pthread_setname_np(pthread_self(),
("network-" + std::to_string(i)).c_str());
std::vector<struct epoll_event> events(event_batch_size);
for (;;) {
int eventCount = epoll_wait(network_epollfd, events.data(),
event_batch_size, -1 /* no timeout */);
if (eventCount == -1) {
if (errno == EINTR) {
continue;
}
perror("epoll_wait");
abort();
}
for (int i = 0; i < eventCount; ++i) {
// Check for shutdown event
if (events[i].data.fd == shutdown_eventfd) {
// Don't read - let other threads see it too
return;
}
for (int i = 0; i < eventCount; ++i) {
// Check for shutdown event
if (events[i].data.fd == shutdown_eventfd) {
// Don't read eventfd - all threads need to see shutdown signal
return;
}
// Take ownership from epoll: raw pointer -> unique_ptr
std::unique_ptr<Connection> conn{
static_cast<Connection *>(events[i].data.ptr)};
conn->tsan_acquire();
events[i].data.ptr =
nullptr; // Clear epoll pointer (we own it now)
const int fd = conn->fd;
// Take ownership from epoll: raw pointer -> unique_ptr
std::unique_ptr<Connection> conn{
static_cast<Connection *>(events[i].data.ptr)};
conn->tsan_acquire();
events[i].data.ptr = nullptr; // Clear epoll pointer (we own it now)
const int fd = conn->fd;
if (events[i].events & (EPOLLERR | EPOLLHUP | EPOLLRDHUP)) {
// Connection closed or error occurred - unique_ptr destructor
// cleans up
continue;
}
if (events[i].events & (EPOLLERR | EPOLLHUP | EPOLLRDHUP)) {
// Connection closed or error occurred - unique_ptr destructor
// cleans up
continue;
}
if (events[i].events & EPOLLIN) {
conn->readBytes(max_request_size);
}
if (events[i].events & EPOLLIN) {
conn->readBytes(max_request_size);
}
if (events[i].events & EPOLLOUT) {
bool done = conn->writeBytes();
if (done) {
continue;
}
}
if (conn->tasks.empty()) {
events[i].events = EPOLLIN | EPOLLONESHOT | EPOLLRDHUP;
} else {
events[i].events = EPOLLOUT | EPOLLONESHOT | EPOLLRDHUP;
}
// Transfer ownership back to epoll: unique_ptr -> raw pointer
conn->tsan_release();
events[i].data.ptr =
conn.release(); // epoll now owns the connection
int e = epoll_ctl(network_epollfd, EPOLL_CTL_MOD, fd, &events[i]);
if (e == -1) {
perror("epoll_ctl");
abort(); // Process termination - OS cleans up leaked connection
}
if (events[i].events & EPOLLOUT) {
bool done = conn->writeBytes();
if (done) {
continue;
}
}
});
if (conn->tasks.empty()) {
events[i].events = EPOLLIN | EPOLLONESHOT | EPOLLRDHUP;
} else {
events[i].events = EPOLLOUT | EPOLLONESHOT | EPOLLRDHUP;
}
// Transfer ownership back to epoll: unique_ptr -> raw pointer
conn->tsan_release();
events[i].data.ptr = conn.release(); // epoll now owns the connection
int e = epoll_ctl(network_epollfd, EPOLL_CTL_MOD, fd, &events[i]);
if (e == -1) {
perror("epoll_ctl");
abort(); // Connection leaked on abort() is acceptable - OS cleanup
}
}
}
});
}
// Accept threads from configuration
@@ -403,7 +407,7 @@ int main(int argc, char *argv[]) {
for (int j = 0; j < ready; ++j) {
if (events[j].data.fd == shutdown_eventfd) {
// Don't read - let other threads see it too
// Don't read eventfd - all threads need to see shutdown signal
return;
}
@@ -425,7 +429,8 @@ int main(int argc, char *argv[]) {
}
// Check connection limit (0 means unlimited). Limiting
// connections is best effort but it's the best we can do.
// connections is best effort - race condition between check and
// increment is acceptable for this use case
if (max_connections > 0 &&
activeConnections.load(std::memory_order_relaxed) >=
max_connections) {
@@ -447,14 +452,13 @@ int main(int argc, char *argv[]) {
int e = epoll_ctl(network_epollfd, EPOLL_CTL_ADD, fd, &event);
if (e == -1) {
perror("epoll_ctl");
abort();
abort(); // Connection leaked on abort() is acceptable - OS
// cleanup
}
}
}
}
}
close(accept_epollfd);
});
}