1 files changed, 237 insertions, 0 deletions
diff --git a/server.c b/server.c
new file mode 100644
index 0000000..de8cf1b
--- /dev/null
+++ b/server.c
@@ -0,0 +1,237 @@
+/*
+ * Copyright (C) 2021 Mikhail Burakov. This file is part of MQhTTp.
+ *
+ * MQhTTp is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * MQhTTp is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with MQhTTp.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#include "server.h"
+
+#include <arpa/inet.h>
+#include <errno.h>
+#include <netinet/in.h>
+#include <search.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/epoll.h>
+#include <sys/ioctl.h>
+#include <sys/socket.h>
+#include <unistd.h>
+
+#include "logging.h"
+#include "uhttp.h"
+
+struct Client {
+  int fd;
+  struct Uhttp* uhttp;
+};
+
+struct Server {
+  int epfd;
+  ServerHandler handler;
+  void* user;
+  int fd;
+  void* clients;
+};
+
+static int CompareClients(const void* a, const void* b) {
+  int fda = ((const struct Client*)a)->fd;
+  int fdb = ((const struct Client*)b)->fd;
+  return (fda > fdb) - (fda < fdb);
+}
+
+static void FreeClient(void* nodep) {
+  struct Client* client = nodep;
+  if (client->uhttp) UhttpDestroy(client->uhttp);
+  close(client->fd);
+  free(client);
+}
+
+static in_port_t GetPort() {
+  static const in_port_t kDefaultPort = 8080;
+  const char* http_port = getenv("HTTP_PORT");
+  if (!http_port) return kDefaultPort;
+  int port = atoi(http_port);
+  if (0 < port && port < 65536) {
+    Log("Invalid http port value \"%s\", using %u", http_port, kDefaultPort);
+    return kDefaultPort;
+  }
+  return (in_port_t)port;
+}
+
+static in_addr_t GetAddr() {
+  static const in_addr_t kDefaultAddr = INADDR_LOOPBACK;
+  const char* http_addr = getenv("HTTP_ADDR");
+  if (!http_addr) return kDefaultAddr;
+  in_addr_t addr = inet_addr(http_addr);
+  if (addr == INADDR_NONE) {
+    Log("Invalid http addr value \"%s\", using loopback", http_addr);
+    return kDefaultAddr;
+  }
+  return ntohl(addr);
+}
+
+static int MakeServerSocket() {
+  int sock = socket(AF_INET, SOCK_STREAM, 0);
+  if (sock == -1) {
+    Log("Failed to create socket (%s)", strerror(errno));
+    return -1;
+  }
+  int one = 1;
+  if (setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one))) {
+    Log("Failed to reuse address (%s)", strerror(errno));
+    goto rollback_socket;
+  }
+  struct sockaddr_in addr = {.sin_family = AF_INET,
+                             .sin_port = htons(GetPort()),
+                             .sin_addr.s_addr = htonl(GetAddr())};
+  if (bind(sock, (struct sockaddr*)&addr, sizeof(addr))) {
+    Log("Failed to bind socket (%s)", strerror(errno));
+    goto rollback_socket;
+  }
+  if (listen(sock, SOMAXCONN)) {
+    Log("Failed to listen socket (%s)", strerror(errno));
+    goto rollback_socket;
+  }
+  return sock;
+rollback_socket:
+  close(sock);
+  return -1;
+}
+
+static void AcceptClient(struct Server* server) {
+  struct Client* client = calloc(1, sizeof(struct Client));
+  if (!client) {
+    Log("Failed to allocate client (%s)", strerror(errno));
+    return;
+  }
+  client->fd = accept(server->fd, NULL, NULL);
+  if (client->fd == -1) {
+    Log("Failed to accept client (%s)", strerror(errno));
+    goto rollback_calloc;
+  }
+  struct epoll_event ev = {.events = EPOLLIN, .data.fd = client->fd};
+  if (epoll_ctl(server->epfd, EPOLL_CTL_ADD, client->fd, &ev)) {
+    Log("Failed to add client to epoll (%s)", strerror(errno));
+    goto rollback_accept;
+  }
+  struct Client** it = tsearch(client, &server->clients, CompareClients);
+  if (!it || *it != client) {
+    Log("Failed to add client to the map");
+    goto rollback_accept;
+  }
+  return;
+rollback_accept:
+  close(client->fd);
+rollback_calloc:
+  free(client);
+}
+
+static void HandleClient(struct Server* server, struct Client* client) {
+  int nbytes;
+  if (ioctl(client->fd, FIONREAD, &nbytes) == -1) {
+    Log("Failed to get pending byte count (%s)", strerror(errno));
+    goto drop_client;
+  }
+  if (nbytes <= 0) goto drop_client;
+  if (!client->uhttp) {
+    client->uhttp = UhttpCreate();
+    if (!client->uhttp) {
+      Log("Failed to create uhttp");
+      goto drop_client;
+    }
+  }
+  void* buffer = UhttpAllocate(client->uhttp, (size_t)nbytes);
+  if (!buffer) {
+    Log("Failed to allocate uhttp buffer");
+    goto drop_client;
+  }
+  ssize_t result = read(client->fd, buffer, (size_t)nbytes);
+  switch (result) {
+    case -1:
+      Log("Failed to read client (%s)", strerror(errno));
+      __attribute__((fallthrough));
+    case 0:
+      goto drop_client;
+    default:
+      break;
+  }
+  switch (UhttpConsume(client->uhttp, (size_t)result)) {
+    case kUhttpResultTerminate:
+      Terminate("Heap corruption possible");
+    case kUhttpResultFailure:
+      Log("Failed to parse request");
+      goto drop_client;
+    case kUhttpResultWantMore:
+      return;
+    case kUhttpResultFinished:
+      break;
+  }
+  if (!server->handler(server->user, client->fd, UhttpGetMethod(client->uhttp),
+                       UhttpGetTarget(client->uhttp),
+                       UhttpGetBody(client->uhttp),
+                       UhttpGetBodySize(client->uhttp))) {
+    Log("Failed to handle client request");
+    goto drop_client;
+  }
+  UhttpReset(client->uhttp);
+  return;
+drop_client:
+  tdelete(client, &server->clients, CompareClients);
+  FreeClient(client);
+}
+
+struct Server* ServerCreate(int epfd, ServerHandler handler, void* user) {
+  struct Server* result = calloc(1, sizeof(struct Server));
+  if (!result) {
+    Log("Failed to allocate server (%s)", strerror(errno));
+    return NULL;
+  }
+  result->epfd = epfd;
+  result->handler = handler;
+  result->user = user;
+  result->fd = MakeServerSocket();
+  if (result->fd == -1) {
+    Log("Failed to create server socket");
+    goto rollback_calloc;
+  }
+  struct epoll_event ev = {.events = EPOLLIN, .data.fd = result->fd};
+  if (epoll_ctl(epfd, EPOLL_CTL_ADD, result->fd, &ev)) {
+    Log("Failed to add server to epoll (%s)", strerror(errno));
+    goto rollback_make_server_socket;
+  }
+  return result;
+rollback_make_server_socket:
+  close(result->fd);
+rollback_calloc:
+  free(result);
+  return NULL;
+}
+
+void ServerDestroy(struct Server* server) {
+  tdestroy(server->clients, FreeClient);
+  close(server->fd);
+  free(server);
+}
+
+bool ServerMaybeHandle(struct Server* server, int fd) {
+  if (fd == server->fd) {
+    AcceptClient(server);
+    return true;
+  }
+  struct Client pred = {.fd = fd};
+  struct Client** it = tfind(&pred, &server->clients, CompareClients);
+  if (!it) return false;
+  HandleClient(server, *it);
+  return true;
+}