Wire up IPC server

1 files changed, 411 insertions, 0 deletions

diff --git a/sway/ipc-server.c b/sway/ipc-server.c
new file mode 100644
index 00000000..f3a6469b
--- /dev/null
+++ b/sway/ipc-server.c
@@ -0,0 +1,411 @@
+// See https://i3wm.org/docs/ipc.html for protocol information
+#ifndef __FreeBSD__
+// Any value will hide SOCK_CLOEXEC on FreeBSD (__BSD_VISIBLE=0)
+#define _XOPEN_SOURCE 700
+#endif
+#include <assert.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <json-c/json.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/socket.h>
+#include <sys/ioctl.h>
+#include <sys/un.h>
+#include <unistd.h>
+#include <wayland-server.h>
+#include "sway/commands.h"
+#include "sway/ipc-json.h"
+#include "sway/ipc-server.h"
+#include "sway/server.h"
+#include "list.h"
+#include "log.h"
+
+static int ipc_socket = -1;
+static struct wl_event_source *ipc_event_source =  NULL;
+static struct sockaddr_un *ipc_sockaddr = NULL;
+static list_t *ipc_client_list = NULL;
+
+static const char ipc_magic[] = {'i', '3', '-', 'i', 'p', 'c'};
+
+struct ipc_client {
+        struct wl_event_source *event_source;
+        struct wl_event_source *writable_event_source;
+        struct sway_server *server;
+        int fd;
+        uint32_t payload_length;
+        uint32_t security_policy;
+        enum ipc_command_type current_command;
+        enum ipc_command_type subscribed_events;
+        size_t write_buffer_len;
+        size_t write_buffer_size;
+        char *write_buffer;
+};
+
+struct sockaddr_un *ipc_user_sockaddr(void);
+int ipc_handle_connection(int fd, uint32_t mask, void *data);
+int ipc_client_handle_readable(int client_fd, uint32_t mask, void *data);
+int ipc_client_handle_writable(int client_fd, uint32_t mask, void *data);
+void ipc_client_disconnect(struct ipc_client *client);
+void ipc_client_handle_command(struct ipc_client *client);
+bool ipc_send_reply(struct ipc_client *client, const char *payload, uint32_t payload_length);
+
+void ipc_init(struct sway_server *server) {
+        ipc_socket = socket(AF_UNIX, SOCK_STREAM | SOCK_NONBLOCK | SOCK_CLOEXEC, 0);
+        if (ipc_socket == -1) {
+                sway_abort("Unable to create IPC socket");
+        }
+
+        ipc_sockaddr = ipc_user_sockaddr();
+
+        // We want to use socket name set by user, not existing socket from another sway instance.
+        if (getenv("SWAYSOCK") != NULL && access(getenv("SWAYSOCK"), F_OK) == -1) {
+                strncpy(ipc_sockaddr->sun_path, getenv("SWAYSOCK"), sizeof(ipc_sockaddr->sun_path));
+                ipc_sockaddr->sun_path[sizeof(ipc_sockaddr->sun_path) - 1] = 0;
+        }
+
+        unlink(ipc_sockaddr->sun_path);
+        if (bind(ipc_socket, (struct sockaddr *)ipc_sockaddr, sizeof(*ipc_sockaddr)) == -1) {
+                sway_abort("Unable to bind IPC socket");
+        }
+
+        if (listen(ipc_socket, 3) == -1) {
+                sway_abort("Unable to listen on IPC socket");
+        }
+
+        // Set i3 IPC socket path so that i3-msg works out of the box
+        setenv("I3SOCK", ipc_sockaddr->sun_path, 1);
+        setenv("SWAYSOCK", ipc_sockaddr->sun_path, 1);
+
+        ipc_client_list = create_list();
+
+        ipc_event_source = wl_event_loop_add_fd(server->wl_event_loop, ipc_socket,
+                        WL_EVENT_READABLE, ipc_handle_connection, server);
+}
+
+void ipc_terminate(void) {
+        if (ipc_event_source) {
+                wl_event_source_remove(ipc_event_source);
+        }
+        close(ipc_socket);
+        unlink(ipc_sockaddr->sun_path);
+
+        list_free(ipc_client_list);
+
+        if (ipc_sockaddr) {
+                free(ipc_sockaddr);
+        }
+}
+
+struct sockaddr_un *ipc_user_sockaddr(void) {
+        struct sockaddr_un *ipc_sockaddr = malloc(sizeof(struct sockaddr_un));
+        if (ipc_sockaddr == NULL) {
+                sway_abort("Can't allocate ipc_sockaddr");
+        }
+
+        ipc_sockaddr->sun_family = AF_UNIX;
+        int path_size = sizeof(ipc_sockaddr->sun_path);
+
+        // Env var typically set by logind, e.g. "/run/user/<user-id>"
+        const char *dir = getenv("XDG_RUNTIME_DIR");
+        if (!dir) {
+                dir = "/tmp";
+        }
+        if (path_size <= snprintf(ipc_sockaddr->sun_path, path_size,
+                        "%s/sway-ipc.%i.%i.sock", dir, getuid(), getpid())) {
+                sway_abort("Socket path won't fit into ipc_sockaddr->sun_path");
+        }
+
+        return ipc_sockaddr;
+}
+
+int ipc_handle_connection(int fd, uint32_t mask, void *data) {
+        (void) fd;
+        struct sway_server *server = data;
+        sway_log(L_DEBUG, "Event on IPC listening socket");
+        assert(mask == WL_EVENT_READABLE);
+
+        int client_fd = accept(ipc_socket, NULL, NULL);
+        if (client_fd == -1) {
+                sway_log_errno(L_ERROR, "Unable to accept IPC client connection");
+                return 0;
+        }
+
+        int flags;
+        if ((flags = fcntl(client_fd, F_GETFD)) == -1
+                        || fcntl(client_fd, F_SETFD, flags|FD_CLOEXEC) == -1) {
+                sway_log_errno(L_ERROR, "Unable to set CLOEXEC on IPC client socket");
+                close(client_fd);
+                return 0;
+        }
+        if ((flags = fcntl(client_fd, F_GETFL)) == -1
+                        || fcntl(client_fd, F_SETFL, flags|O_NONBLOCK) == -1) {
+                sway_log_errno(L_ERROR, "Unable to set NONBLOCK on IPC client socket");
+                close(client_fd);
+                return 0;
+        }
+
+        struct ipc_client *client = malloc(sizeof(struct ipc_client));
+        if (!client) {
+                sway_log(L_ERROR, "Unable to allocate ipc client");
+                close(client_fd);
+                return 0;
+        }
+        client->server = server;
+        client->payload_length = 0;
+        client->fd = client_fd;
+        client->subscribed_events = 0;
+        client->event_source = wl_event_loop_add_fd(server->wl_event_loop,
+                        client_fd, WL_EVENT_READABLE, ipc_client_handle_readable, client);
+        client->writable_event_source = NULL;
+
+        client->write_buffer_size = 128;
+        client->write_buffer_len = 0;
+        client->write_buffer = malloc(client->write_buffer_size);
+        if (!client->write_buffer) {
+                sway_log(L_ERROR, "Unable to allocate ipc client write buffer");
+                close(client_fd);
+                return 0;
+        }
+
+        sway_log(L_DEBUG, "New client: fd %d", client_fd);
+        list_add(ipc_client_list, client);
+        return 0;
+}
+
+static const int ipc_header_size = sizeof(ipc_magic) + 8;
+
+int ipc_client_handle_readable(int client_fd, uint32_t mask, void *data) {
+        struct ipc_client *client = data;
+
+        if (mask & WL_EVENT_ERROR) {
+                sway_log(L_ERROR, "IPC Client socket error, removing client");
+                ipc_client_disconnect(client);
+                return 0;
+        }
+
+        if (mask & WL_EVENT_HANGUP) {
+                sway_log(L_DEBUG, "Client %d hung up", client->fd);
+                ipc_client_disconnect(client);
+                return 0;
+        }
+
+        sway_log(L_DEBUG, "Client %d readable", client->fd);
+
+        int read_available;
+        if (ioctl(client_fd, FIONREAD, &read_available) == -1) {
+                sway_log_errno(L_INFO, "Unable to read IPC socket buffer size");
+                ipc_client_disconnect(client);
+                return 0;
+        }
+
+        // Wait for the rest of the command payload in case the header has already been read
+        if (client->payload_length > 0) {
+                if ((uint32_t)read_available >= client->payload_length) {
+                        ipc_client_handle_command(client);
+                }
+                return 0;
+        }
+
+        if (read_available < ipc_header_size) {
+                return 0;
+        }
+
+        uint8_t buf[ipc_header_size];
+        uint32_t *buf32 = (uint32_t*)(buf + sizeof(ipc_magic));
+        // Should be fully available, because read_available >= ipc_header_size
+        ssize_t received = recv(client_fd, buf, ipc_header_size, 0);
+        if (received == -1) {
+                sway_log_errno(L_INFO, "Unable to receive header from IPC client");
+                ipc_client_disconnect(client);
+                return 0;
+        }
+
+        if (memcmp(buf, ipc_magic, sizeof(ipc_magic)) != 0) {
+                sway_log(L_DEBUG, "IPC header check failed");
+                ipc_client_disconnect(client);
+                return 0;
+        }
+
+        client->payload_length = buf32[0];
+        client->current_command = (enum ipc_command_type)buf32[1];
+
+        if (read_available - received >= (long)client->payload_length) {
+                ipc_client_handle_command(client);
+        }
+
+        return 0;
+}
+
+int ipc_client_handle_writable(int client_fd, uint32_t mask, void *data) {
+        struct ipc_client *client = data;
+
+        if (mask & WL_EVENT_ERROR) {
+                sway_log(L_ERROR, "IPC Client socket error, removing client");
+                ipc_client_disconnect(client);
+                return 0;
+        }
+
+        if (mask & WL_EVENT_HANGUP) {
+                sway_log(L_DEBUG, "Client %d hung up", client->fd);
+                ipc_client_disconnect(client);
+                return 0;
+        }
+
+        if (client->write_buffer_len <= 0) {
+                return 0;
+        }
+
+        sway_log(L_DEBUG, "Client %d writable", client->fd);
+
+        ssize_t written = write(client->fd, client->write_buffer, client->write_buffer_len);
+
+        if (written == -1 && errno == EAGAIN) {
+                return 0;
+        } else if (written == -1) {
+                sway_log_errno(L_INFO, "Unable to send data from queue to IPC client");
+                ipc_client_disconnect(client);
+                return 0;
+        }
+
+        memmove(client->write_buffer, client->write_buffer + written, client->write_buffer_len - written);
+        client->write_buffer_len -= written;
+
+        if (client->write_buffer_len == 0 && client->writable_event_source) {
+                wl_event_source_remove(client->writable_event_source);
+                client->writable_event_source = NULL;
+        }
+
+        return 0;
+}
+
+void ipc_client_disconnect(struct ipc_client *client) {
+        if (!sway_assert(client != NULL, "client != NULL")) {
+                return;
+        }
+
+        if (client->fd != -1) {
+                shutdown(client->fd, SHUT_RDWR);
+        }
+
+        sway_log(L_INFO, "IPC Client %d disconnected", client->fd);
+        wl_event_source_remove(client->event_source);
+        if (client->writable_event_source) {
+                wl_event_source_remove(client->writable_event_source);
+        }
+        int i = 0;
+        while (i < ipc_client_list->length && ipc_client_list->items[i] != client) {
+                i++;
+        }
+        list_del(ipc_client_list, i);
+        free(client->write_buffer);
+        close(client->fd);
+        free(client);
+}
+
+void ipc_client_handle_command(struct ipc_client *client) {
+        if (!sway_assert(client != NULL, "client != NULL")) {
+                return;
+        }
+
+        char *buf = malloc(client->payload_length + 1);
+        if (!buf) {
+                sway_log_errno(L_INFO, "Unable to allocate IPC payload");
+                ipc_client_disconnect(client);
+                return;
+        }
+        if (client->payload_length > 0) {
+                // Payload should be fully available
+                ssize_t received = recv(client->fd, buf, client->payload_length, 0);
+                if (received == -1)
+                {
+                        sway_log_errno(L_INFO, "Unable to receive payload from IPC client");
+                        ipc_client_disconnect(client);
+                        free(buf);
+                        return;
+                }
+        }
+        buf[client->payload_length] = '\0';
+
+        const char *error_denied = "{ \"success\": false, \"error\": \"Permission denied\" }";
+
+        switch (client->current_command) {
+        case IPC_COMMAND:
+        {
+                struct cmd_results *results = handle_command(buf);
+                const char *json = cmd_results_to_json(results);
+                char reply[256];
+                int length = snprintf(reply, sizeof(reply), "%s", json);
+                ipc_send_reply(client, reply, (uint32_t) length);
+                free_cmd_results(results);
+                goto exit_cleanup;
+        }
+
+        case IPC_GET_VERSION:
+        {
+                json_object *version = ipc_json_get_version();
+                const char *json_string = json_object_to_json_string(version);
+                ipc_send_reply(client, json_string, (uint32_t)strlen(json_string));
+                json_object_put(version); // free
+                goto exit_cleanup;
+        }
+
+        default:
+                sway_log(L_INFO, "Unknown IPC command type %i", client->current_command);
+                goto exit_cleanup;
+        }
+
+        ipc_send_reply(client, error_denied, (uint32_t)strlen(error_denied));
+        sway_log(L_DEBUG, "Denied IPC client access to %i", client->current_command);
+
+exit_cleanup:
+        client->payload_length = 0;
+        free(buf);
+        return;
+}
+
+bool ipc_send_reply(struct ipc_client *client, const char *payload, uint32_t payload_length) {
+        assert(payload);
+
+        char data[ipc_header_size];
+        uint32_t *data32 = (uint32_t*)(data + sizeof(ipc_magic));
+
+        memcpy(data, ipc_magic, sizeof(ipc_magic));
+        data32[0] = payload_length;
+        data32[1] = client->current_command;
+
+        while (client->write_buffer_len + ipc_header_size + payload_length >=
+                                 client->write_buffer_size) {
+                client->write_buffer_size *= 2;
+        }
+
+        if (client->write_buffer_size > 4e6) { // 4 MB
+                sway_log(L_ERROR, "Client write buffer too big, disconnecting client");
+                ipc_client_disconnect(client);
+                return false;
+        }
+
+        char *new_buffer = realloc(client->write_buffer, client->write_buffer_size);
+        if (!new_buffer) {
+                sway_log(L_ERROR, "Unable to reallocate ipc client write buffer");
+                ipc_client_disconnect(client);
+                return false;
+        }
+        client->write_buffer = new_buffer;
+
+        memcpy(client->write_buffer + client->write_buffer_len, data, ipc_header_size);
+        client->write_buffer_len += ipc_header_size;
+        memcpy(client->write_buffer + client->write_buffer_len, payload, payload_length);
+        client->write_buffer_len += payload_length;
+
+        if (!client->writable_event_source) {
+                client->writable_event_source = wl_event_loop_add_fd(
+                                server.wl_event_loop, client->fd, WL_EVENT_WRITABLE,
+                                ipc_client_handle_writable, client);
+        }
+
+        sway_log(L_DEBUG, "Added IPC reply to client %d queue: %s", client->fd, payload);
+        return true;
+}