Emulate Linux socket timeout signaling on Windows

test/posix/socket_timeout_signal_test.c

@@ -0,0 +1,215 @@
+#include <arpa/inet.h>
+#include <cosmo.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <netinet/in.h>
+#include <pthread.h>
+#include <signal.h>
+#include <stdatomic.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/socket.h>
+#include <sys/time.h>
+#include <sys/types.h>
+#include <unistd.h>
+#include "libc/limits.h"
+
+/**
+ * @fileoverview SO_RCVTIMEO + SA_RESTART interaction test
+ *
+ * This code tests that setting a read timeout on a socket will cause
+ * read() to change its signal handling behavior from @restartable to
+ * @norestart. This is currently the case on GNU/Systemd and Windows.
+ */
+
+struct sockaddr_in serv_addr;
+atomic_bool g_ready_for_conn;
+atomic_bool g_ready_for_data;
+atomic_bool g_ready_for_more;
+atomic_bool g_ready_for_exit;
+atomic_bool got_sigusr1;
+atomic_bool got_sigusr2;
+
+void on_sigusr1(int sig) {
+  got_sigusr1 = true;
+}
+
+void on_sigusr2(int sig) {
+  got_sigusr2 = true;
+}
+
+void *server_thread(void *arg) {
+  int server, client;
+  struct timeval timeout;
+  socklen_t len;
+  struct sockaddr_in cli_addr;
+
+  // create listening socket
+  server = socket(AF_INET, SOCK_STREAM, 0);
+  if (server == -1) {
+    perror("socket");
+    exit(31);
+  }
+
+  // initialize server address
+  memset(&serv_addr, 0, sizeof(serv_addr));
+  serv_addr.sin_family = AF_INET;
+  serv_addr.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
+  serv_addr.sin_port = htons(0);
+
+  // bind socket
+  if (bind(server, (struct sockaddr *)&serv_addr, sizeof(serv_addr))) {
+    perror("bind");
+    exit(32);
+  }
+
+  // get assigned port
+  len = sizeof(serv_addr);
+  if (getsockname(server, (struct sockaddr *)&serv_addr, &len)) {
+    perror("getsockname");
+    exit(30);
+  }
+
+  // listen on the socket
+  if (listen(server, SOMAXCONN)) {
+    perror("listen");
+    exit(33);
+  }
+
+  // wake main thread
+  g_ready_for_conn = true;
+
+  // accept connection
+  len = sizeof(cli_addr);
+  client = accept(server, (struct sockaddr *)&cli_addr, &len);
+  if (client == -1) {
+    perror("accept");
+    exit(35);
+  }
+
+  // wake main thread
+  g_ready_for_data = true;
+
+  // check read() has @restartable behavior
+  char buf[1];
+  int rc = read(client, buf, 1);
+  if (rc != -1)
+    exit(35);
+  if (errno != EINTR)
+    exit(36);
+  if (!got_sigusr1)
+    exit(37);
+  if (!got_sigusr2)
+    exit(38);
+  got_sigusr1 = false;
+  got_sigusr2 = false;
+
+  // install a socket receive timeout
+  timeout.tv_sec = 5000000;
+  timeout.tv_usec = 0;
+  if (setsockopt(client, SOL_SOCKET, SO_RCVTIMEO, &timeout,
+                 sizeof(timeout) + !IsNetbsd())) {
+    perror("setsockopt");
+    exit(34);
+  }
+
+  // wake main thread
+  g_ready_for_more = true;
+
+  // check read() has @norestart behavior
+  rc = read(client, buf, 1);
+  if (rc != -1)
+    exit(35);
+  if (errno != EINTR)
+    exit(36);
+  if (!got_sigusr1)
+    exit(37);
+
+  // here's the whammy
+  if (IsLinux() || IsWindows()) {
+    if (got_sigusr2)
+      exit(38);
+  } else {
+    if (!got_sigusr2)
+      exit(38);
+  }
+
+  // wait for main thread
+  for (;;)
+    if (g_ready_for_exit)
+      break;
+
+  // close listening socket
+  if (close(server))
+    exit(40);
+  if (close(client))
+    exit(39);
+  return 0;
+}
+
+int main() {
+
+  // handle signals
+  struct sigaction sa = {0};
+  sa.sa_handler = on_sigusr1;
+  sa.sa_flags = SA_RESTART;
+  sigaction(SIGUSR1, &sa, 0);
+  sa.sa_handler = on_sigusr2;
+  sa.sa_flags = 0;
+  sigaction(SIGUSR2, &sa, 0);
+
+  // create server thread
+  pthread_t th;
+  if (pthread_create(&th, 0, server_thread, 0))
+    return 1;
+
+  // wait for thread
+  for (;;)
+    if (g_ready_for_conn)
+      break;
+
+  // create socket
+  int client = socket(AF_INET, SOCK_STREAM, 0);
+  if (client == -1) {
+    perror("socket");
+    return 2;
+  }
+
+  // connect to server
+  if (connect(client, (struct sockaddr *)&serv_addr, sizeof(serv_addr)) == -1) {
+    perror("connect");
+    return 3;
+  }
+
+  // wait for thread
+  for (;;)
+    if (g_ready_for_data)
+      break;
+
+  usleep(100e3);
+  if (pthread_kill(th, SIGUSR1))
+    return 4;
+
+  usleep(100e3);
+  if (pthread_kill(th, SIGUSR2))
+    return 5;
+
+  // wait for thread
+  for (;;)
+    if (g_ready_for_more)
+      break;
+
+  usleep(100e3);
+  if (pthread_kill(th, SIGUSR1))
+    return 4;
+
+  usleep(400e3);
+  if (pthread_kill(th, SIGUSR2))
+    return 5;
+
+  g_ready_for_exit = true;
+
+  if (pthread_join(th, 0))
+    return 20;
+}