From ff11ee21efc11b341e3300d5140509e2088a992d Mon Sep 17 00:00:00 2001
From: Stephanie Wang <swang93@mit.edu>
Date: Sat, 17 Sep 2016 15:15:18 -0700
Subject: [PATCH] Convert to streaming sockets (#7)

* Convert to streaming sockets

* Formatting
---
 sockets.c           | 42 ++++++++++++++++++++++++++++++------------
 sockets.h           |  1 +
 test/socket_tests.c | 12 ++++++++----
 3 files changed, 39 insertions(+), 16 deletions(-)

diff --git a/sockets.c b/sockets.c
index 6fd41e476..82ca490f7 100644
--- a/sockets.c
+++ b/sockets.c
@@ -17,7 +17,7 @@ int bind_ipc_sock(const char *socket_pathname) {
   struct sockaddr_un socket_address;
   int socket_fd;
 
-  socket_fd = socket(AF_UNIX, SOCK_DGRAM, 0);
+  socket_fd = socket(AF_UNIX, SOCK_STREAM, 0);
   if (socket_fd < 0) {
     LOG_ERR("socket() failed for pathname %s.", socket_pathname);
     return -1;
@@ -38,6 +38,7 @@ int bind_ipc_sock(const char *socket_pathname) {
     LOG_ERR("Bind failed for pathname %s.", socket_pathname);
     return -1;
   }
+  listen(socket_fd, 5);
 
   return socket_fd;
 }
@@ -49,7 +50,7 @@ int connect_ipc_sock(const char *socket_pathname) {
   struct sockaddr_un socket_address;
   int socket_fd;
 
-  socket_fd = socket(AF_UNIX, SOCK_DGRAM, 0);
+  socket_fd = socket(AF_UNIX, SOCK_STREAM, 0);
   if (socket_fd < 0) {
     LOG_ERR("socket() failed for pathname %s.", socket_pathname);
     return -1;
@@ -77,33 +78,50 @@ int connect_ipc_sock(const char *socket_pathname) {
 void send_ipc_sock(int socket_fd, char *message) {
   int length = strlen(message);
   int nbytes;
-  nbytes = send(socket_fd, (char *) &length, sizeof(length), 0);
+  nbytes = write(socket_fd, (char *) &length, sizeof(length));
   if (nbytes == -1) {
-    fprintf(stderr, "Error sending to socket.\n");
+    LOG_ERR("Error sending to socket.\n");
     return;
   }
-  nbytes = send(socket_fd, (char *) message, length * sizeof(char), 0);
+  nbytes = write(socket_fd, (char *) message, length * sizeof(char));
   if (nbytes == -1) {
-    fprintf(stderr, "Error sending to socket.\n");
+    LOG_ERR("Error sending to socket.\n");
     return;
   }
 }
 
+/* Accept a new client connection on the given socket
+ * descriptor. Returns a descriptor for the new socket. */
+int accept_client(int socket_fd) {
+  struct sockaddr_un client_addr;
+  int client_fd, client_len;
+  client_len = sizeof(client_addr);
+  client_fd = accept(socket_fd, (struct sockaddr *) &client_addr,
+                     (socklen_t *) &client_len);
+  if (client_fd < 0) {
+    LOG_ERR("Error reading from socket.");
+    return -1;
+  }
+  return client_fd;
+}
+
 /* Receives a message on the given socket file descriptor. Allocates and
  * returns a pointer to the message.
  * NOTE: Caller must free the message! */
 char *recv_ipc_sock(int socket_fd) {
   int length;
   int nbytes;
-  nbytes = recv(socket_fd, &length, sizeof(length), 0);
-  if (nbytes == -1) {
-    fprintf(stderr, "Error receiving from socket.\n");
+  nbytes = read(socket_fd, &length, sizeof(length));
+  if (nbytes < 0) {
+    LOG_ERR("Error reading length of message from socket.");
     return NULL;
   }
+
   char *message = malloc((length + 1) * sizeof(char));
-  nbytes = recv(socket_fd, message, length * sizeof(char), 0);
-  if (nbytes == -1) {
-    fprintf(stderr, "Error receiving from socket.\n");
+  nbytes = read(socket_fd, message, length);
+  if (nbytes < 0) {
+    LOG_ERR("Error reading message from socket.");
+    free(message);
     return NULL;
   }
   message[length] = '\0';
diff --git a/sockets.h b/sockets.h
index 7ad0c7141..a563470c9 100644
--- a/sockets.h
+++ b/sockets.h
@@ -5,6 +5,7 @@
 int bind_ipc_sock(const char* socket_pathname);
 int connect_ipc_sock(const char* socket_pathname);
 void send_ipc_sock(int socket_fd, char* message);
+int accept_client(int socket_fd);
 char* recv_ipc_sock(int socket_fd);
 
 #endif
diff --git a/test/socket_tests.c b/test/socket_tests.c
index 1fa352246..b57ab9000 100644
--- a/test/socket_tests.c
+++ b/test/socket_tests.c
@@ -5,7 +5,7 @@
 
 #include "sockets.h"
 
-SUITE(event_loop_tests);
+SUITE(socket_tests);
 
 TEST ipc_socket_test(void) {
   const char* socket_pathname = "test-socket";
@@ -20,11 +20,15 @@ TEST ipc_socket_test(void) {
     ASSERT(socket_fd >= 0);
     send_ipc_sock(socket_fd, test_string);
     close(socket_fd);
+    exit(0);
   } else {
-    char* message = recv_ipc_sock(socket_fd);
+    int client_fd = accept_client(socket_fd);
+    ASSERT(client_fd >= 0);
+    char* message = recv_ipc_sock(client_fd);
     ASSERT(message != NULL);
     ASSERT_STR_EQ(test_string, message);
     free(message);
+    close(client_fd);
     close(socket_fd);
     unlink(socket_pathname);
   }
@@ -32,7 +36,7 @@ TEST ipc_socket_test(void) {
   PASS();
 }
 
-SUITE(event_loop_tests) {
+SUITE(socket_tests) {
   RUN_TEST(ipc_socket_test);
 }
 
@@ -40,6 +44,6 @@ GREATEST_MAIN_DEFS();
 
 int main(int argc, char** argv) {
   GREATEST_MAIN_BEGIN();
-  RUN_SUITE(event_loop_tests);
+  RUN_SUITE(socket_tests);
   GREATEST_MAIN_END();
 }