1 files changed, 273 insertions, 0 deletions
diff --git a/src/nvim/msgpack_rpc/server.c b/src/nvim/msgpack_rpc/server.c
new file mode 100644
index 0000000000..33e01fe562
--- /dev/null
+++ b/src/nvim/msgpack_rpc/server.c
@@ -0,0 +1,273 @@
+#include <assert.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdint.h>
+
+#include <uv.h>
+
+#include "nvim/msgpack_rpc/channel.h"
+#include "nvim/msgpack_rpc/server.h"
+#include "nvim/os/os.h"
+#include "nvim/ascii.h"
+#include "nvim/vim.h"
+#include "nvim/memory.h"
+#include "nvim/message.h"
+#include "nvim/tempfile.h"
+#include "nvim/map.h"
+#include "nvim/path.h"
+
+#define MAX_CONNECTIONS 32
+#define ADDRESS_MAX_SIZE 256
+#define NEOVIM_DEFAULT_TCP_PORT 7450
+#define LISTEN_ADDRESS_ENV_VAR "NVIM_LISTEN_ADDRESS"
+
+typedef enum {
+  kServerTypeTcp,
+  kServerTypePipe
+} ServerType;
+
+typedef struct {
+  // Type of the union below
+  ServerType type;
+
+  // This is either a tcp server or unix socket(named pipe on windows)
+  union {
+    struct {
+      uv_tcp_t handle;
+      struct sockaddr_in addr;
+    } tcp;
+    struct {
+      uv_pipe_t handle;
+      char addr[ADDRESS_MAX_SIZE];
+    } pipe;
+  } socket;
+} Server;
+
+static PMap(cstr_t) *servers = NULL;
+
+#ifdef INCLUDE_GENERATED_DECLARATIONS
+# include "msgpack_rpc/server.c.generated.h"
+#endif
+
+/// Initializes the module
+bool server_init(void)
+{
+  servers = pmap_new(cstr_t)();
+
+  if (!os_getenv(LISTEN_ADDRESS_ENV_VAR)) {
+    char *listen_address = (char *)vim_tempname();
+    os_setenv(LISTEN_ADDRESS_ENV_VAR, listen_address, 1);
+    free(listen_address);
+  }
+
+  return server_start((char *)os_getenv(LISTEN_ADDRESS_ENV_VAR)) == 0;
+}
+
+/// Teardown the server module
+void server_teardown(void)
+{
+  if (!servers) {
+    return;
+  }
+
+  Server *server;
+
+  map_foreach_value(servers, server, {
+    if (server->type == kServerTypeTcp) {
+      uv_close((uv_handle_t *)&server->socket.tcp.handle, free_server);
+    } else {
+      uv_close((uv_handle_t *)&server->socket.pipe.handle, free_server);
+    }
+  });
+}
+
+/// Starts listening on arbitrary tcp/unix addresses specified by
+/// `endpoint` for API calls. The type of socket used(tcp or unix/pipe) will
+/// be determined by parsing `endpoint`: If it's a valid tcp address in the
+/// 'ip[:port]' format, then it will be tcp socket. The port is optional
+/// and if omitted will default to NEOVIM_DEFAULT_TCP_PORT. Otherwise it will
+/// be a unix socket or named pipe.
+///
+/// @param endpoint Address of the server. Either a 'ip[:port]' string or an
+///        arbitrary identifier(trimmed to 256 bytes) for the unix socket or
+///        named pipe.
+/// @returns zero if successful, one on a regular error, and negative errno
+///          on failure to bind or connect.
+int server_start(const char *endpoint)
+  FUNC_ATTR_NONNULL_ALL
+{
+  char addr[ADDRESS_MAX_SIZE];
+
+  // Trim to `ADDRESS_MAX_SIZE`
+  if (xstrlcpy(addr, endpoint, sizeof(addr)) >= sizeof(addr)) {
+    // TODO(aktau): since this is not what the user wanted, perhaps we
+    // should return an error here
+    EMSG2("Address was too long, truncated to %s", addr);
+  }
+
+  // Check if the server already exists
+  if (pmap_has(cstr_t)(servers, addr)) {
+    EMSG2("Already listening on %s", addr);
+    return 1;
+  }
+
+  ServerType server_type = kServerTypeTcp;
+  Server *server = xmalloc(sizeof(Server));
+  char ip[16], *ip_end = strrchr(addr, ':');
+
+  if (!ip_end) {
+    ip_end = strchr(addr, NUL);
+  }
+
+  uint32_t addr_len = ip_end - addr;
+
+  if (addr_len > sizeof(ip) - 1) {
+    // Maximum length of an IP address buffer is 15(eg: 255.255.255.255)
+    addr_len = sizeof(ip) - 1;
+  }
+
+  // Extract the address part
+  xstrlcpy(ip, addr, addr_len + 1);
+
+  int port = NEOVIM_DEFAULT_TCP_PORT;
+
+  if (*ip_end == ':') {
+    // Extract the port
+    long lport = strtol(ip_end + 1, NULL, 10); // NOLINT
+    if (lport <= 0 || lport > 0xffff) {
+      // Invalid port, treat as named pipe or unix socket
+      server_type = kServerTypePipe;
+    } else {
+      port = (int) lport;
+    }
+  }
+
+  if (server_type == kServerTypeTcp) {
+    // Try to parse ip address
+    if (uv_ip4_addr(ip, port, &server->socket.tcp.addr)) {
+      // Invalid address, treat as named pipe or unix socket
+      server_type = kServerTypePipe;
+    }
+  }
+
+  int result;
+
+  if (server_type == kServerTypeTcp) {
+    // Listen on tcp address/port
+    uv_tcp_init(uv_default_loop(), &server->socket.tcp.handle);
+    server->socket.tcp.handle.data = server;
+    result = uv_tcp_bind(&server->socket.tcp.handle,
+                         (const struct sockaddr *)&server->socket.tcp.addr,
+                         0);
+    if (result == 0) {
+      result = uv_listen((uv_stream_t *)&server->socket.tcp.handle,
+                         MAX_CONNECTIONS,
+                         connection_cb);
+      if (result) {
+        uv_close((uv_handle_t *)&server->socket.tcp.handle, free_server);
+      }
+    }
+  } else {
+    // Listen on named pipe or unix socket
+    xstrlcpy(server->socket.pipe.addr, addr, sizeof(server->socket.pipe.addr));
+    uv_pipe_init(uv_default_loop(), &server->socket.pipe.handle, 0);
+    server->socket.pipe.handle.data = server;
+    result = uv_pipe_bind(&server->socket.pipe.handle,
+                          server->socket.pipe.addr);
+    if (result == 0) {
+      result = uv_listen((uv_stream_t *)&server->socket.pipe.handle,
+                         MAX_CONNECTIONS,
+                         connection_cb);
+
+      if (result) {
+        uv_close((uv_handle_t *)&server->socket.pipe.handle, free_server);
+      }
+    }
+  }
+
+  assert(result <= 0);  // libuv should have returned -errno or zero.
+  if (result < 0) {
+    if (result == -EACCES) {
+      // Libuv converts ENOENT to EACCES for Windows compatibility, but if
+      // the parent directory does not exist, ENOENT would be more accurate.
+      *path_tail((char_u *) addr) = NUL;
+      if (!os_file_exists((char_u *) addr)) {
+        result = -ENOENT;
+      }
+    }
+    EMSG2("Failed to start server: %s", uv_strerror(result));
+    free(server);
+    return result;
+  }
+
+  server->type = server_type;
+
+  // Add the server to the hash table
+  pmap_put(cstr_t)(servers, addr, server);
+
+  return 0;
+}
+
+/// Stops listening on the address specified by `endpoint`.
+///
+/// @param endpoint Address of the server.
+void server_stop(char *endpoint)
+{
+  Server *server;
+  char addr[ADDRESS_MAX_SIZE];
+
+  // Trim to `ADDRESS_MAX_SIZE`
+  xstrlcpy(addr, endpoint, sizeof(addr));
+
+  if ((server = pmap_get(cstr_t)(servers, addr)) == NULL) {
+    EMSG2("Not listening on %s", addr);
+    return;
+  }
+
+  if (server->type == kServerTypeTcp) {
+    uv_close((uv_handle_t *)&server->socket.tcp.handle, free_server);
+  } else {
+    uv_close((uv_handle_t *)&server->socket.pipe.handle, free_server);
+  }
+
+  pmap_del(cstr_t)(servers, addr);
+}
+
+static void connection_cb(uv_stream_t *server, int status)
+{
+  int result;
+  uv_stream_t *client;
+  Server *srv = server->data;
+
+  if (status < 0) {
+    abort();
+  }
+
+  if (srv->type == kServerTypeTcp) {
+    client = xmalloc(sizeof(uv_tcp_t));
+    uv_tcp_init(uv_default_loop(), (uv_tcp_t *)client);
+  } else {
+    client = xmalloc(sizeof(uv_pipe_t));
+    uv_pipe_init(uv_default_loop(), (uv_pipe_t *)client, 0);
+  }
+
+  result = uv_accept(server, client);
+
+  if (result) {
+    EMSG2("Failed to accept connection: %s", uv_strerror(result));
+    uv_close((uv_handle_t *)client, free_client);
+    return;
+  }
+
+  channel_from_stream(client);
+}
+
+static void free_client(uv_handle_t *handle)
+{
+  free(handle);
+}
+
+static void free_server(uv_handle_t *handle)
+{
+  free(handle->data);
+}