added IPC server

sharing/linux/daemon/ipc_server.cc

@@ -0,0 +1,160 @@
+#include "ipc_server.h"
+#include <thread>
+#include <cerrno>
+#include <cstring>
+#include <iostream>
+
+std::string IPCServer::Read() {
+  std::string cmd;
+  absl::MutexLock lock(lock_);
+
+  size_t pos = read_buf.find('\n');
+
+  if (pos != std::string::npos) {
+    cmd = read_buf.substr(0, pos);
+    read_buf.erase(0, pos + 1);
+  }
+
+  return cmd;
+}
+
+void IPCServer::Stop() {
+  running_.store(false);
+
+  if (client_fd_ >= 0) {
+    shutdown(client_fd_, SHUT_RDWR);
+    close(client_fd_);
+    client_fd_ = -1;
+  }
+
+  if (sock_fd_ >= 0) {
+    shutdown(sock_fd_, SHUT_RDWR);
+    close(sock_fd_);
+    sock_fd_ = -1;
+  }
+
+  unlink(SOCK_PATH.data());
+}
+
+void IPCServer::InitialiseSock() {
+  sock_fd_ = socket(AF_UNIX, SOCK_STREAM, 0);
+  if (sock_fd_ == -1) {
+    return;
+  }
+
+  unlink(SOCK_PATH.data());
+
+  memset(&addr, 0, sizeof(addr));
+  addr.sun_family = AF_UNIX;
+  strncpy(addr.sun_path, SOCK_PATH.data(), sizeof(addr.sun_path) - 1);
+
+  if (bind(sock_fd_, reinterpret_cast<sockaddr*>(&addr), sizeof(addr)) == -1) {
+    close(sock_fd_);
+    sock_fd_ = -1;
+    return;
+  }
+
+  if (listen(sock_fd_, 1) == -1) {
+    close(sock_fd_);
+    sock_fd_ = -1;
+    return;
+  }
+}
+void IPCServer::Recv() {
+  while (running_.load()) {
+    pollfd pfd{};
+    pfd.fd = client_fd_;
+    pfd.events = POLLIN;
+
+    int poll_result = poll(&pfd, 1, 100);
+
+    if (!running_.load()) {
+      return;
+    }
+
+    if (poll_result < 0) {
+      if (errno == EINTR) {
+        continue;
+      }
+      return;
+    }
+
+    if (poll_result == 0) {
+      continue;
+    }
+
+    if (pfd.revents & (POLLNVAL | POLLERR)) {
+      return;
+    }
+
+    if (pfd.revents & (POLLIN | POLLHUP)) {
+      char buf[1024]{};
+
+      ssize_t n = recv(client_fd_, buf, sizeof(buf), 0);
+
+      if (n > 0) {
+        absl::MutexLock lock(lock_);
+        read_buf.append(buf, static_cast<size_t>(n));
+        continue;
+      }
+
+      if (n == 0) {
+        return;
+      }
+
+      if (errno == EINTR) {
+        continue;
+      }
+
+      if (errno == EAGAIN || errno == EWOULDBLOCK) {
+        continue;
+      }
+
+      return;
+    }
+  }
+}
+
+void IPCServer::StartEventLoop() {
+  running_.store(true);
+
+  InitialiseSock();
+
+  if (sock_fd_ < 0) {
+    running_.store(false);
+    return;
+  }
+
+  while (running_.load()) {
+    sockaddr_un client_addr{};
+    socklen_t addr_len = sizeof(client_addr);
+
+    int accepted_fd =
+        accept(sock_fd_, reinterpret_cast<sockaddr*>(&client_addr), &addr_len);
+
+    if (!running_.load()) {
+      if (accepted_fd >= 0) {
+        close(accepted_fd);
+      }
+      break;
+    }
+
+    if (accepted_fd < 0) {
+      if (errno == EINTR) {
+        continue;
+      }
+      break;
+    }
+
+    client_fd_ = accepted_fd;
+
+    Recv();
+
+    if (client_fd_ >= 0) {
+      close(client_fd_);
+      client_fd_ = -1;
+    }
+  }
+
+  Stop();
+}