/* SPDX-License-Identifier: LGPL-2.1-or-later */ #include #include #include #include "alloc-util.h" #include "errno-util.h" #include "fd-util.h" #include "glyph-util.h" #include "hashmap.h" #include "io-util.h" #include "iovec-util.h" #include "list.h" #include "path-util.h" #include "process-util.h" #include "selinux-util.h" #include "serialize.h" #include "set.h" #include "socket-util.h" #include "string-table.h" #include "string-util.h" #include "strv.h" #include "time-util.h" #include "umask-util.h" #include "user-util.h" #include "varlink.h" #include "varlink-internal.h" #include "varlink-org.varlink.service.h" #include "varlink-io.systemd.h" #include "version.h" #define VARLINK_DEFAULT_CONNECTIONS_MAX 4096U #define VARLINK_DEFAULT_CONNECTIONS_PER_UID_MAX 1024U #define VARLINK_DEFAULT_TIMEOUT_USEC (45U*USEC_PER_SEC) #define VARLINK_BUFFER_MAX (16U*1024U*1024U) #define VARLINK_READ_SIZE (64U*1024U) typedef enum VarlinkState { /* Client side states */ VARLINK_IDLE_CLIENT, VARLINK_AWAITING_REPLY, VARLINK_AWAITING_REPLY_MORE, VARLINK_CALLING, VARLINK_CALLED, VARLINK_PROCESSING_REPLY, /* Server side states */ VARLINK_IDLE_SERVER, VARLINK_PROCESSING_METHOD, VARLINK_PROCESSING_METHOD_MORE, VARLINK_PROCESSING_METHOD_ONEWAY, VARLINK_PROCESSED_METHOD, VARLINK_PENDING_METHOD, VARLINK_PENDING_METHOD_MORE, /* Common states (only during shutdown) */ VARLINK_PENDING_DISCONNECT, VARLINK_PENDING_TIMEOUT, VARLINK_PROCESSING_DISCONNECT, VARLINK_PROCESSING_TIMEOUT, VARLINK_PROCESSING_FAILURE, VARLINK_DISCONNECTED, _VARLINK_STATE_MAX, _VARLINK_STATE_INVALID = -EINVAL, } VarlinkState; /* Tests whether we are not yet disconnected. Note that this is true during all states where the connection * is still good for something, and false only when it's dead for good. This means: when we are * asynchronously connecting to a peer and the connect() is still pending, then this will return 'true', as * the connection is still good, and we are likely to be able to properly operate on it soon. */ #define VARLINK_STATE_IS_ALIVE(state) \ IN_SET(state, \ VARLINK_IDLE_CLIENT, \ VARLINK_AWAITING_REPLY, \ VARLINK_AWAITING_REPLY_MORE, \ VARLINK_CALLING, \ VARLINK_CALLED, \ VARLINK_PROCESSING_REPLY, \ VARLINK_IDLE_SERVER, \ VARLINK_PROCESSING_METHOD, \ VARLINK_PROCESSING_METHOD_MORE, \ VARLINK_PROCESSING_METHOD_ONEWAY, \ VARLINK_PROCESSED_METHOD, \ VARLINK_PENDING_METHOD, \ VARLINK_PENDING_METHOD_MORE) typedef struct VarlinkJsonQueueItem VarlinkJsonQueueItem; /* A queued message we shall write into the socket, along with the file descriptors to send at the same * time. This queue item binds them together so that message/fd boundaries are maintained throughout the * whole pipeline. */ struct VarlinkJsonQueueItem { LIST_FIELDS(VarlinkJsonQueueItem, queue); JsonVariant *data; size_t n_fds; int fds[]; }; struct Varlink { unsigned n_ref; VarlinkServer *server; VarlinkState state; bool connecting; /* This boolean indicates whether the socket fd we are operating on is currently * processing an asynchronous connect(). In that state we watch the socket for * EPOLLOUT, but we refrain from calling read() or write() on the socket as that * will trigger ENOTCONN. Note that this boolean is kept separate from the * VarlinkState above on purpose: while the connect() is still not complete we * already want to allow queuing of messages and similar. Thus it's nice to keep * these two state concepts separate: the VarlinkState encodes what our own view of * the connection is, i.e. whether we think it's a server, a client, and has * something queued already, while 'connecting' tells us a detail about the * transport used below, that should have no effect on how we otherwise accept and * process operations from the user. * * Or to say this differently: VARLINK_STATE_IS_ALIVE(state) tells you whether the * connection is good to use, even if it might not be fully connected * yet. connecting=true then informs you that actually we are still connecting, and * the connection is actually not established yet and thus any requests you enqueue * now will still work fine but will be queued only, not sent yet, but that * shouldn't stop you from using the connection, since eventually whatever you queue * *will* be sent. * * Or to say this even differently: 'state' is a high-level ("application layer" * high, if you so will) state, while 'conecting' is a low-level ("transport layer" * low, if you so will) state, and while they are not entirely unrelated and * sometimes propagate effects to each other they are only asynchronously connected * at most. */ unsigned n_pending; int fd; char *input_buffer; /* valid data starts at input_buffer_index, ends at input_buffer_index+input_buffer_size */ size_t input_buffer_index; size_t input_buffer_size; size_t input_buffer_unscanned; void *input_control_buffer; size_t input_control_buffer_size; char *output_buffer; /* valid data starts at output_buffer_index, ends at output_buffer_index+output_buffer_size */ size_t output_buffer_index; size_t output_buffer_size; int *input_fds; /* file descriptors associated with the data in input_buffer (for fd passing) */ size_t n_input_fds; int *output_fds; /* file descriptors associated with the data in output_buffer (for fd passing) */ size_t n_output_fds; /* Further messages to output not yet formatted into text, and thus not included in output_buffer * yet. We keep them separate from output_buffer, to not violate fd message boundaries: we want that * each fd that is sent is associated with its fds, and that fds cannot be accidentally associated * with preceding or following messages. */ LIST_HEAD(VarlinkJsonQueueItem, output_queue); VarlinkJsonQueueItem *output_queue_tail; /* The fds to associate with the next message that is about to be enqueued. The user first pushes the * fds it intends to send via varlink_push_fd() into this queue, and then once the message data is * submitted we'll combine the fds and the message data into one. */ int *pushed_fds; size_t n_pushed_fds; VarlinkReply reply_callback; JsonVariant *current; VarlinkSymbol *current_method; struct ucred ucred; bool ucred_acquired:1; bool write_disconnected:1; bool read_disconnected:1; bool prefer_read_write:1; bool got_pollhup:1; bool allow_fd_passing_input:1; bool allow_fd_passing_output:1; bool output_buffer_sensitive:1; /* whether to erase the output buffer after writing it to the socket */ int af; /* address family if socket; AF_UNSPEC if not socket; negative if not known */ usec_t timestamp; usec_t timeout; void *userdata; char *description; sd_event *event; sd_event_source *io_event_source; sd_event_source *time_event_source; sd_event_source *quit_event_source; sd_event_source *defer_event_source; pid_t exec_pid; }; static const char* const varlink_state_table[_VARLINK_STATE_MAX] = { [VARLINK_IDLE_CLIENT] = "idle-client", [VARLINK_AWAITING_REPLY] = "awaiting-reply", [VARLINK_AWAITING_REPLY_MORE] = "awaiting-reply-more", [VARLINK_CALLING] = "calling", [VARLINK_CALLED] = "called", [VARLINK_PROCESSING_REPLY] = "processing-reply", [VARLINK_IDLE_SERVER] = "idle-server", [VARLINK_PROCESSING_METHOD] = "processing-method", [VARLINK_PROCESSING_METHOD_MORE] = "processing-method-more", [VARLINK_PROCESSING_METHOD_ONEWAY] = "processing-method-oneway", [VARLINK_PROCESSED_METHOD] = "processed-method", [VARLINK_PENDING_METHOD] = "pending-method", [VARLINK_PENDING_METHOD_MORE] = "pending-method-more", [VARLINK_PENDING_DISCONNECT] = "pending-disconnect", [VARLINK_PENDING_TIMEOUT] = "pending-timeout", [VARLINK_PROCESSING_DISCONNECT] = "processing-disconnect", [VARLINK_PROCESSING_TIMEOUT] = "processing-timeout", [VARLINK_PROCESSING_FAILURE] = "processing-failure", [VARLINK_DISCONNECTED] = "disconnected", }; DEFINE_PRIVATE_STRING_TABLE_LOOKUP_TO_STRING(varlink_state, VarlinkState); #define varlink_log_errno(v, error, fmt, ...) \ log_debug_errno(error, "%s: " fmt, varlink_description(v), ##__VA_ARGS__) #define varlink_log(v, fmt, ...) \ log_debug("%s: " fmt, varlink_description(v), ##__VA_ARGS__) #define varlink_server_log_errno(s, error, fmt, ...) \ log_debug_errno(error, "%s: " fmt, varlink_server_description(s), ##__VA_ARGS__) #define varlink_server_log(s, fmt, ...) \ log_debug("%s: " fmt, varlink_server_description(s), ##__VA_ARGS__) static int varlink_format_queue(Varlink *v); static void varlink_server_test_exit_on_idle(VarlinkServer *s); static const char *varlink_description(Varlink *v) { return (v ? v->description : NULL) ?: "varlink"; } static const char *varlink_server_description(VarlinkServer *s) { return (s ? s->description : NULL) ?: "varlink"; } static VarlinkJsonQueueItem *varlink_json_queue_item_free(VarlinkJsonQueueItem *q) { if (!q) return NULL; json_variant_unref(q->data); close_many(q->fds, q->n_fds); return mfree(q); } static VarlinkJsonQueueItem *varlink_json_queue_item_new(JsonVariant *m, const int fds[], size_t n_fds) { VarlinkJsonQueueItem *q; assert(m); assert(fds || n_fds == 0); q = malloc(offsetof(VarlinkJsonQueueItem, fds) + sizeof(int) * n_fds); if (!q) return NULL; *q = (VarlinkJsonQueueItem) { .data = json_variant_ref(m), .n_fds = n_fds, }; memcpy_safe(q->fds, fds, n_fds * sizeof(int)); return TAKE_PTR(q); } static void varlink_set_state(Varlink *v, VarlinkState state) { assert(v); assert(state >= 0 && state < _VARLINK_STATE_MAX); if (v->state < 0) varlink_log(v, "Setting state %s", varlink_state_to_string(state)); else varlink_log(v, "Changing state %s %s %s", varlink_state_to_string(v->state), special_glyph(SPECIAL_GLYPH_ARROW_RIGHT), varlink_state_to_string(state)); v->state = state; } static int varlink_new(Varlink **ret) { Varlink *v; assert(ret); v = new(Varlink, 1); if (!v) return -ENOMEM; *v = (Varlink) { .n_ref = 1, .fd = -EBADF, .state = _VARLINK_STATE_INVALID, .ucred = UCRED_INVALID, .timestamp = USEC_INFINITY, .timeout = VARLINK_DEFAULT_TIMEOUT_USEC, .af = -1, }; *ret = v; return 0; } int varlink_connect_address(Varlink **ret, const char *address) { _cleanup_(varlink_unrefp) Varlink *v = NULL; union sockaddr_union sockaddr; int r; assert_return(ret, -EINVAL); assert_return(address, -EINVAL); r = varlink_new(&v); if (r < 0) return log_debug_errno(r, "Failed to create varlink object: %m"); v->fd = socket(AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0); if (v->fd < 0) return log_debug_errno(errno, "Failed to create AF_UNIX socket: %m"); v->fd = fd_move_above_stdio(v->fd); v->af = AF_UNIX; r = sockaddr_un_set_path(&sockaddr.un, address); if (r < 0) { if (r != -ENAMETOOLONG) return log_debug_errno(r, "Failed to set socket address '%s': %m", address); /* This is a file system path, and too long to fit into sockaddr_un. Let's connect via O_PATH * to this socket. */ r = connect_unix_path(v->fd, AT_FDCWD, address); } else r = RET_NERRNO(connect(v->fd, &sockaddr.sa, r)); if (r < 0) { if (!IN_SET(r, -EAGAIN, -EINPROGRESS)) return log_debug_errno(r, "Failed to connect to %s: %m", address); v->connecting = true; /* We are asynchronously connecting, i.e. the connect() is being * processed in the background. As long as that's the case the socket * is in a special state: it's there, we can poll it for EPOLLOUT, but * if we attempt to write() to it before we see EPOLLOUT we'll get * ENOTCONN (and not EAGAIN, like we would for a normal connected * socket that isn't writable at the moment). Since ENOTCONN on write() * hence can mean two different things (i.e. connection not complete * yet vs. already disconnected again), we store as a boolean whether * we are still in connect(). */ } varlink_set_state(v, VARLINK_IDLE_CLIENT); *ret = TAKE_PTR(v); return 0; } int varlink_connect_exec(Varlink **ret, const char *_command, char **_argv) { _cleanup_close_pair_ int pair[2] = EBADF_PAIR; _cleanup_(sigkill_waitp) pid_t pid = 0; _cleanup_free_ char *command = NULL; _cleanup_strv_free_ char **argv = NULL; int r; assert_return(ret, -EINVAL); assert_return(_command, -EINVAL); /* Copy the strings, in case they point into our own argv[], which we'll invalidate shortly because * we rename the child process */ command = strdup(_command); if (!command) return -ENOMEM; if (strv_isempty(_argv)) argv = strv_new(command); else argv = strv_copy(_argv); if (!argv) return -ENOMEM; log_debug("Forking off Varlink child process '%s'.", command); if (socketpair(AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0, pair) < 0) return log_debug_errno(errno, "Failed to allocate AF_UNIX socket pair: %m"); r = safe_fork_full( "(sd-vlexec)", /* stdio_fds= */ NULL, /* except_fds= */ (int[]) { pair[1] }, /* n_except_fds= */ 1, FORK_RESET_SIGNALS|FORK_CLOSE_ALL_FDS|FORK_DEATHSIG_SIGTERM|FORK_REOPEN_LOG|FORK_LOG|FORK_RLIMIT_NOFILE_SAFE, &pid); if (r < 0) return log_debug_errno(r, "Failed to spawn process: %m"); if (r == 0) { char spid[DECIMAL_STR_MAX(pid_t)+1]; const char *setenv_list[] = { "LISTEN_FDS", "1", "LISTEN_PID", spid, "LISTEN_FDNAMES", "varlink", NULL, NULL, }; /* Child */ pair[0] = -EBADF; r = move_fd(pair[1], 3, /* cloexec= */ false); if (r < 0) { log_debug_errno(r, "Failed to move file descriptor to 3: %m"); _exit(EXIT_FAILURE); } xsprintf(spid, PID_FMT, pid); STRV_FOREACH_PAIR(a, b, setenv_list) { if (setenv(*a, *b, /* override= */ true) < 0) { log_debug_errno(errno, "Failed to set environment variable '%s': %m", *a); _exit(EXIT_FAILURE); } } execvp(command, argv); log_debug_errno(r, "Failed to invoke process '%s': %m", command); _exit(EXIT_FAILURE); } pair[1] = safe_close(pair[1]); Varlink *v; r = varlink_new(&v); if (r < 0) return log_debug_errno(r, "Failed to create varlink object: %m"); v->fd = TAKE_FD(pair[0]); v->af = AF_UNIX; v->exec_pid = TAKE_PID(pid); varlink_set_state(v, VARLINK_IDLE_CLIENT); *ret = v; return 0; } int varlink_connect_url(Varlink **ret, const char *url) { _cleanup_free_ char *c = NULL; const char *p; bool exec; int r; assert_return(ret, -EINVAL); assert_return(url, -EINVAL); // FIXME: Add support for vsock:, ssh-exec:, ssh-unix: URL schemes here. (The latter with OpenSSH // 9.4's -W switch for referencing remote AF_UNIX sockets.) /* The Varlink URL scheme is a bit underdefined. We support only the unix: transport for now, plus an * exec: transport we made up ourselves. Strictly speaking this shouldn't even be called URL, since * it has nothing to do with Internet URLs by RFC. */ p = startswith(url, "unix:"); if (p) exec = false; else { p = startswith(url, "exec:"); if (!p) return log_debug_errno(SYNTHETIC_ERRNO(EPROTONOSUPPORT), "URL scheme not supported."); exec = true; } /* The varlink.org reference C library supports more than just file system paths. We might want to * support that one day too. For now simply refuse that. */ if (p[strcspn(p, ";?#")] != '\0') return log_debug_errno(SYNTHETIC_ERRNO(EPROTONOSUPPORT), "URL parameterization with ';', '?', '#' not supported."); if (exec || p[0] != '@') { /* no validity checks for abstract namespace */ if (!path_is_absolute(p)) return log_debug_errno(SYNTHETIC_ERRNO(EINVAL), "Specified path not absolute, refusing."); r = path_simplify_alloc(p, &c); if (r < 0) return r; if (!path_is_normalized(c)) return log_debug_errno(SYNTHETIC_ERRNO(EINVAL), "Specified path is not normalized, refusing."); } if (exec) return varlink_connect_exec(ret, c, NULL); return varlink_connect_address(ret, c ?: p); } int varlink_connect_fd(Varlink **ret, int fd) { Varlink *v; int r; assert_return(ret, -EINVAL); assert_return(fd >= 0, -EBADF); r = fd_nonblock(fd, true); if (r < 0) return log_debug_errno(r, "Failed to make fd %d nonblocking: %m", fd); r = varlink_new(&v); if (r < 0) return log_debug_errno(r, "Failed to create varlink object: %m"); v->fd = fd; v->af = -1, varlink_set_state(v, VARLINK_IDLE_CLIENT); /* Note that if this function is called we assume the passed socket (if it is one) is already * properly connected, i.e. any asynchronous connect() done on it already completed. Because of that * we'll not set the 'connecting' boolean here, i.e. we don't need to avoid write()ing to the socket * until the connection is fully set up. Behaviour here is hence a bit different from * varlink_connect_address() above, as there we do handle asynchronous connections ourselves and * avoid doing write() on it before we saw EPOLLOUT for the first time. */ *ret = v; return 0; } static void varlink_detach_event_sources(Varlink *v) { assert(v); v->io_event_source = sd_event_source_disable_unref(v->io_event_source); v->time_event_source = sd_event_source_disable_unref(v->time_event_source); v->quit_event_source = sd_event_source_disable_unref(v->quit_event_source); v->defer_event_source = sd_event_source_disable_unref(v->defer_event_source); } static void varlink_clear_current(Varlink *v) { assert(v); /* Clears the currently processed incoming message */ v->current = json_variant_unref(v->current); v->current_method = NULL; close_many(v->input_fds, v->n_input_fds); v->input_fds = mfree(v->input_fds); v->n_input_fds = 0; } static void varlink_clear(Varlink *v) { assert(v); varlink_detach_event_sources(v); v->fd = safe_close(v->fd); varlink_clear_current(v); v->input_buffer = mfree(v->input_buffer); v->output_buffer = v->output_buffer_sensitive ? erase_and_free(v->output_buffer) : mfree(v->output_buffer); v->input_control_buffer = mfree(v->input_control_buffer); v->input_control_buffer_size = 0; close_many(v->output_fds, v->n_output_fds); v->output_fds = mfree(v->output_fds); v->n_output_fds = 0; close_many(v->pushed_fds, v->n_pushed_fds); v->pushed_fds = mfree(v->pushed_fds); v->n_pushed_fds = 0; LIST_CLEAR(queue, v->output_queue, varlink_json_queue_item_free); v->output_queue_tail = NULL; v->event = sd_event_unref(v->event); if (v->exec_pid > 0) { sigterm_wait(v->exec_pid); v->exec_pid = 0; } } static Varlink* varlink_destroy(Varlink *v) { if (!v) return NULL; /* If this is called the server object must already been unreffed here. Why that? because when we * linked up the varlink connection with the server object we took one ref in each direction */ assert(!v->server); varlink_clear(v); free(v->description); return mfree(v); } DEFINE_TRIVIAL_REF_UNREF_FUNC(Varlink, varlink, varlink_destroy); static int varlink_test_disconnect(Varlink *v) { assert(v); /* Tests whether we the connection has been terminated. We are careful to not stop processing it * prematurely, since we want to handle half-open connections as well as possible and want to flush * out and read data before we close down if we can. */ /* Already disconnected? */ if (!VARLINK_STATE_IS_ALIVE(v->state)) return 0; /* Wait until connection setup is complete, i.e. until asynchronous connect() completes */ if (v->connecting) return 0; /* Still something to write and we can write? Stay around */ if (v->output_buffer_size > 0 && !v->write_disconnected) return 0; /* Both sides gone already? Then there's no need to stick around */ if (v->read_disconnected && v->write_disconnected) goto disconnect; /* If we are waiting for incoming data but the read side is shut down, disconnect. */ if (IN_SET(v->state, VARLINK_AWAITING_REPLY, VARLINK_AWAITING_REPLY_MORE, VARLINK_CALLING, VARLINK_IDLE_SERVER) && v->read_disconnected) goto disconnect; /* Similar, if are a client that hasn't written anything yet but the write side is dead, also * disconnect. We also explicitly check for POLLHUP here since we likely won't notice the write side * being down if we never wrote anything. */ if (v->state == VARLINK_IDLE_CLIENT && (v->write_disconnected || v->got_pollhup)) goto disconnect; /* We are on the server side and still want to send out more replies, but we saw POLLHUP already, and * either got no buffered bytes to write anymore or already saw a write error. In that case we should * shut down the varlink link. */ if (IN_SET(v->state, VARLINK_PENDING_METHOD, VARLINK_PENDING_METHOD_MORE) && (v->write_disconnected || v->output_buffer_size == 0) && v->got_pollhup) goto disconnect; return 0; disconnect: varlink_set_state(v, VARLINK_PENDING_DISCONNECT); return 1; } static int varlink_write(Varlink *v) { ssize_t n; int r; assert(v); if (!VARLINK_STATE_IS_ALIVE(v->state)) return 0; if (v->connecting) /* Writing while we are still wait for a non-blocking connect() to complete will * result in ENOTCONN, hence exit early here */ return 0; if (v->write_disconnected) return 0; /* If needed let's convert some output queue json variants into text form */ r = varlink_format_queue(v); if (r < 0) return r; if (v->output_buffer_size == 0) return 0; assert(v->fd >= 0); if (v->n_output_fds > 0) { /* If we shall send fds along, we must use sendmsg() */ struct iovec iov = { .iov_base = v->output_buffer + v->output_buffer_index, .iov_len = v->output_buffer_size, }; struct msghdr mh = { .msg_iov = &iov, .msg_iovlen = 1, .msg_controllen = CMSG_SPACE(sizeof(int) * v->n_output_fds), }; mh.msg_control = alloca0(mh.msg_controllen); struct cmsghdr *control = CMSG_FIRSTHDR(&mh); control->cmsg_len = CMSG_LEN(sizeof(int) * v->n_output_fds); control->cmsg_level = SOL_SOCKET; control->cmsg_type = SCM_RIGHTS; memcpy(CMSG_DATA(control), v->output_fds, sizeof(int) * v->n_output_fds); n = sendmsg(v->fd, &mh, MSG_DONTWAIT|MSG_NOSIGNAL); } else { /* We generally prefer recv()/send() (mostly because of MSG_NOSIGNAL) but also want to be compatible * with non-socket IO, hence fall back automatically. * * Use a local variable to help gcc figure out that we set 'n' in all cases. */ bool prefer_write = v->prefer_read_write; if (!prefer_write) { n = send(v->fd, v->output_buffer + v->output_buffer_index, v->output_buffer_size, MSG_DONTWAIT|MSG_NOSIGNAL); if (n < 0 && errno == ENOTSOCK) prefer_write = v->prefer_read_write = true; } if (prefer_write) n = write(v->fd, v->output_buffer + v->output_buffer_index, v->output_buffer_size); } if (n < 0) { if (errno == EAGAIN) return 0; if (ERRNO_IS_DISCONNECT(errno)) { /* If we get informed about a disconnect on write, then let's remember that, but not * act on it just yet. Let's wait for read() to report the issue first. */ v->write_disconnected = true; return 1; } return -errno; } if (v->output_buffer_sensitive) explicit_bzero_safe(v->output_buffer + v->output_buffer_index, n); v->output_buffer_size -= n; if (v->output_buffer_size == 0) { v->output_buffer_index = 0; v->output_buffer_sensitive = false; /* We can reset the sensitive flag once the buffer is empty */ } else v->output_buffer_index += n; close_many(v->output_fds, v->n_output_fds); v->n_output_fds = 0; v->timestamp = now(CLOCK_MONOTONIC); return 1; } #define VARLINK_FDS_MAX (16U*1024U) static int varlink_read(Varlink *v) { struct iovec iov; struct msghdr mh; size_t rs; ssize_t n; void *p; assert(v); if (!IN_SET(v->state, VARLINK_AWAITING_REPLY, VARLINK_AWAITING_REPLY_MORE, VARLINK_CALLING, VARLINK_IDLE_SERVER)) return 0; if (v->connecting) /* read() on a socket while we are in connect() will fail with EINVAL, hence exit early here */ return 0; if (v->current) return 0; if (v->input_buffer_unscanned > 0) return 0; if (v->read_disconnected) return 0; if (v->input_buffer_size >= VARLINK_BUFFER_MAX) return -ENOBUFS; assert(v->fd >= 0); if (MALLOC_SIZEOF_SAFE(v->input_buffer) <= v->input_buffer_index + v->input_buffer_size) { size_t add; add = MIN(VARLINK_BUFFER_MAX - v->input_buffer_size, VARLINK_READ_SIZE); if (v->input_buffer_index == 0) { if (!GREEDY_REALLOC(v->input_buffer, v->input_buffer_size + add)) return -ENOMEM; } else { char *b; b = new(char, v->input_buffer_size + add); if (!b) return -ENOMEM; memcpy(b, v->input_buffer + v->input_buffer_index, v->input_buffer_size); free_and_replace(v->input_buffer, b); v->input_buffer_index = 0; } } p = v->input_buffer + v->input_buffer_index + v->input_buffer_size; rs = MALLOC_SIZEOF_SAFE(v->input_buffer) - (v->input_buffer_index + v->input_buffer_size); if (v->allow_fd_passing_input) { iov = IOVEC_MAKE(p, rs); /* Allocate the fd buffer on the heap, since we need a lot of space potentially */ if (!v->input_control_buffer) { v->input_control_buffer_size = CMSG_SPACE(sizeof(int) * VARLINK_FDS_MAX); v->input_control_buffer = malloc(v->input_control_buffer_size); if (!v->input_control_buffer) return -ENOMEM; } mh = (struct msghdr) { .msg_iov = &iov, .msg_iovlen = 1, .msg_control = v->input_control_buffer, .msg_controllen = v->input_control_buffer_size, }; n = recvmsg_safe(v->fd, &mh, MSG_DONTWAIT|MSG_CMSG_CLOEXEC); } else { bool prefer_read = v->prefer_read_write; if (!prefer_read) { n = recv(v->fd, p, rs, MSG_DONTWAIT); if (n < 0 && errno == ENOTSOCK) prefer_read = v->prefer_read_write = true; } if (prefer_read) n = read(v->fd, p, rs); } if (n < 0) { if (errno == EAGAIN) return 0; if (ERRNO_IS_DISCONNECT(errno)) { v->read_disconnected = true; return 1; } return -errno; } if (n == 0) { /* EOF */ if (v->allow_fd_passing_input) cmsg_close_all(&mh); v->read_disconnected = true; return 1; } if (v->allow_fd_passing_input) { struct cmsghdr* cmsg; cmsg = cmsg_find(&mh, SOL_SOCKET, SCM_RIGHTS, (socklen_t) -1); if (cmsg) { size_t add; /* We only allow file descriptors to be passed along with the first byte of a * message. If they are passed with any other byte this is a protocol violation. */ if (v->input_buffer_size != 0) { cmsg_close_all(&mh); return -EPROTO; } add = (cmsg->cmsg_len - CMSG_LEN(0)) / sizeof(int); if (add > INT_MAX - v->n_input_fds) { cmsg_close_all(&mh); return -EBADF; } if (!GREEDY_REALLOC(v->input_fds, v->n_input_fds + add)) { cmsg_close_all(&mh); return -ENOMEM; } memcpy_safe(v->input_fds + v->n_input_fds, CMSG_TYPED_DATA(cmsg, int), add * sizeof(int)); v->n_input_fds += add; } } v->input_buffer_size += n; v->input_buffer_unscanned += n; return 1; } static int varlink_parse_message(Varlink *v) { const char *e, *begin; size_t sz; int r; assert(v); if (v->current) return 0; if (v->input_buffer_unscanned <= 0) return 0; assert(v->input_buffer_unscanned <= v->input_buffer_size); assert(v->input_buffer_index + v->input_buffer_size <= MALLOC_SIZEOF_SAFE(v->input_buffer)); begin = v->input_buffer + v->input_buffer_index; e = memchr(begin + v->input_buffer_size - v->input_buffer_unscanned, 0, v->input_buffer_unscanned); if (!e) { v->input_buffer_unscanned = 0; return 0; } sz = e - begin + 1; varlink_log(v, "New incoming message: %s", begin); /* FIXME: should we output the whole message here before validation? * This may produce a non-printable journal entry if the message * is invalid. We may also expose privileged information. */ r = json_parse(begin, 0, &v->current, NULL, NULL); if (r < 0) { /* If we encounter a parse failure flush all data. We cannot possibly recover from this, * hence drop all buffered data now. */ v->input_buffer_index = v->input_buffer_size = v->input_buffer_unscanned = 0; return varlink_log_errno(v, r, "Failed to parse JSON: %m"); } v->input_buffer_size -= sz; if (v->input_buffer_size == 0) v->input_buffer_index = 0; else v->input_buffer_index += sz; v->input_buffer_unscanned = v->input_buffer_size; return 1; } static int varlink_test_timeout(Varlink *v) { assert(v); if (!IN_SET(v->state, VARLINK_AWAITING_REPLY, VARLINK_AWAITING_REPLY_MORE, VARLINK_CALLING)) return 0; if (v->timeout == USEC_INFINITY) return 0; if (now(CLOCK_MONOTONIC) < usec_add(v->timestamp, v->timeout)) return 0; varlink_set_state(v, VARLINK_PENDING_TIMEOUT); return 1; } static int varlink_dispatch_local_error(Varlink *v, const char *error) { int r; assert(v); assert(error); if (!v->reply_callback) return 0; r = v->reply_callback(v, NULL, error, VARLINK_REPLY_ERROR|VARLINK_REPLY_LOCAL, v->userdata); if (r < 0) log_debug_errno(r, "Reply callback returned error, ignoring: %m"); return 1; } static int varlink_dispatch_timeout(Varlink *v) { assert(v); if (v->state != VARLINK_PENDING_TIMEOUT) return 0; varlink_set_state(v, VARLINK_PROCESSING_TIMEOUT); varlink_dispatch_local_error(v, VARLINK_ERROR_TIMEOUT); varlink_close(v); return 1; } static int varlink_dispatch_disconnect(Varlink *v) { assert(v); if (v->state != VARLINK_PENDING_DISCONNECT) return 0; varlink_set_state(v, VARLINK_PROCESSING_DISCONNECT); varlink_dispatch_local_error(v, VARLINK_ERROR_DISCONNECTED); varlink_close(v); return 1; } static int varlink_sanitize_parameters(JsonVariant **v) { int r; assert(v); /* Varlink always wants a parameters list, hence make one if the caller doesn't want any */ if (!*v) return json_variant_new_object(v, NULL, 0); if (json_variant_is_null(*v)) { JsonVariant *empty; r = json_variant_new_object(&empty, NULL, 0); if (r < 0) return r; json_variant_unref(*v); *v = empty; return 0; } if (!json_variant_is_object(*v)) return -EINVAL; return 0; } static int varlink_dispatch_reply(Varlink *v) { _cleanup_(json_variant_unrefp) JsonVariant *parameters = NULL; VarlinkReplyFlags flags = 0; const char *error = NULL; JsonVariant *e; const char *k; int r; assert(v); if (!IN_SET(v->state, VARLINK_AWAITING_REPLY, VARLINK_AWAITING_REPLY_MORE, VARLINK_CALLING)) return 0; if (!v->current) return 0; assert(v->n_pending > 0); if (!json_variant_is_object(v->current)) goto invalid; JSON_VARIANT_OBJECT_FOREACH(k, e, v->current) { if (streq(k, "error")) { if (error) goto invalid; if (!json_variant_is_string(e)) goto invalid; error = json_variant_string(e); flags |= VARLINK_REPLY_ERROR; } else if (streq(k, "parameters")) { if (parameters) goto invalid; if (!json_variant_is_object(e) && !json_variant_is_null(e)) goto invalid; parameters = json_variant_ref(e); } else if (streq(k, "continues")) { if (FLAGS_SET(flags, VARLINK_REPLY_CONTINUES)) goto invalid; if (!json_variant_is_boolean(e)) goto invalid; if (json_variant_boolean(e)) flags |= VARLINK_REPLY_CONTINUES; } else goto invalid; } /* Replies with 'continue' set are only OK if we set 'more' when the method call was initiated */ if (v->state != VARLINK_AWAITING_REPLY_MORE && FLAGS_SET(flags, VARLINK_REPLY_CONTINUES)) goto invalid; /* An error is final */ if (error && FLAGS_SET(flags, VARLINK_REPLY_CONTINUES)) goto invalid; r = varlink_sanitize_parameters(¶meters); if (r < 0) goto invalid; if (IN_SET(v->state, VARLINK_AWAITING_REPLY, VARLINK_AWAITING_REPLY_MORE)) { varlink_set_state(v, VARLINK_PROCESSING_REPLY); if (v->reply_callback) { r = v->reply_callback(v, parameters, error, flags, v->userdata); if (r < 0) log_debug_errno(r, "Reply callback returned error, ignoring: %m"); } varlink_clear_current(v); if (v->state == VARLINK_PROCESSING_REPLY) { assert(v->n_pending > 0); if (!FLAGS_SET(flags, VARLINK_REPLY_CONTINUES)) v->n_pending--; varlink_set_state(v, FLAGS_SET(flags, VARLINK_REPLY_CONTINUES) ? VARLINK_AWAITING_REPLY_MORE : v->n_pending == 0 ? VARLINK_IDLE_CLIENT : VARLINK_AWAITING_REPLY); } } else { assert(v->state == VARLINK_CALLING); varlink_set_state(v, VARLINK_CALLED); } return 1; invalid: varlink_set_state(v, VARLINK_PROCESSING_FAILURE); varlink_dispatch_local_error(v, VARLINK_ERROR_PROTOCOL); varlink_close(v); return 1; } static int generic_method_get_info( Varlink *link, JsonVariant *parameters, VarlinkMethodFlags flags, void *userdata) { _cleanup_strv_free_ char **interfaces = NULL; _cleanup_free_ char *product = NULL; int r; assert(link); if (json_variant_elements(parameters) != 0) return varlink_errorb(link, VARLINK_ERROR_INVALID_PARAMETER, JSON_BUILD_OBJECT( JSON_BUILD_PAIR_VARIANT("parameter", json_variant_by_index(parameters, 0)))); product = strjoin("systemd (", program_invocation_short_name, ")"); if (!product) return -ENOMEM; VarlinkInterface *interface; HASHMAP_FOREACH(interface, ASSERT_PTR(link->server)->interfaces) { r = strv_extend(&interfaces, interface->name); if (r < 0) return r; } strv_sort(interfaces); return varlink_replyb(link, JSON_BUILD_OBJECT( JSON_BUILD_PAIR_STRING("vendor", "The systemd Project"), JSON_BUILD_PAIR_STRING("product", product), JSON_BUILD_PAIR_STRING("version", STRINGIFY(PROJECT_VERSION) " (" GIT_VERSION ")"), JSON_BUILD_PAIR_STRING("url", "https://systemd.io/"), JSON_BUILD_PAIR_STRV("interfaces", interfaces))); } static int generic_method_get_interface_description( Varlink *link, JsonVariant *parameters, VarlinkMethodFlags flags, void *userdata) { static const struct JsonDispatch dispatch_table[] = { { "interface", JSON_VARIANT_STRING, json_dispatch_const_string, 0, JSON_MANDATORY }, {} }; _cleanup_free_ char *text = NULL; const VarlinkInterface *interface; const char *name = NULL; int r; assert(link); r = json_dispatch(parameters, dispatch_table, 0, &name); if (r < 0) return r; interface = hashmap_get(ASSERT_PTR(link->server)->interfaces, name); if (!interface) return varlink_errorb(link, VARLINK_ERROR_INTERFACE_NOT_FOUND, JSON_BUILD_OBJECT( JSON_BUILD_PAIR_STRING("interface", name))); r = varlink_idl_format(interface, &text); if (r < 0) return r; return varlink_replyb(link, JSON_BUILD_OBJECT( JSON_BUILD_PAIR_STRING("description", text))); } static int varlink_dispatch_method(Varlink *v) { _cleanup_(json_variant_unrefp) JsonVariant *parameters = NULL; VarlinkMethodFlags flags = 0; const char *method = NULL; JsonVariant *e; VarlinkMethod callback; const char *k; int r; assert(v); if (v->state != VARLINK_IDLE_SERVER) return 0; if (!v->current) return 0; if (!json_variant_is_object(v->current)) goto invalid; JSON_VARIANT_OBJECT_FOREACH(k, e, v->current) { if (streq(k, "method")) { if (method) goto invalid; if (!json_variant_is_string(e)) goto invalid; method = json_variant_string(e); } else if (streq(k, "parameters")) { if (parameters) goto invalid; if (!json_variant_is_object(e) && !json_variant_is_null(e)) goto invalid; parameters = json_variant_ref(e); } else if (streq(k, "oneway")) { if ((flags & (VARLINK_METHOD_ONEWAY|VARLINK_METHOD_MORE)) != 0) goto invalid; if (!json_variant_is_boolean(e)) goto invalid; if (json_variant_boolean(e)) flags |= VARLINK_METHOD_ONEWAY; } else if (streq(k, "more")) { if ((flags & (VARLINK_METHOD_ONEWAY|VARLINK_METHOD_MORE)) != 0) goto invalid; if (!json_variant_is_boolean(e)) goto invalid; if (json_variant_boolean(e)) flags |= VARLINK_METHOD_MORE; } else goto invalid; } if (!method) goto invalid; r = varlink_sanitize_parameters(¶meters); if (r < 0) goto fail; varlink_set_state(v, (flags & VARLINK_METHOD_MORE) ? VARLINK_PROCESSING_METHOD_MORE : (flags & VARLINK_METHOD_ONEWAY) ? VARLINK_PROCESSING_METHOD_ONEWAY : VARLINK_PROCESSING_METHOD); assert(v->server); /* First consult user supplied method implementations */ callback = hashmap_get(v->server->methods, method); if (!callback) { if (streq(method, "org.varlink.service.GetInfo")) callback = generic_method_get_info; else if (streq(method, "org.varlink.service.GetInterfaceDescription")) callback = generic_method_get_interface_description; } if (callback) { bool invalid = false; v->current_method = hashmap_get(v->server->symbols, method); if (!v->current_method) log_debug("No interface description defined for method '%s', not validating.", method); else { const char *bad_field; r = varlink_idl_validate_method_call(v->current_method, parameters, &bad_field); if (r < 0) { log_debug_errno(r, "Parameters for method %s() didn't pass validation on field '%s': %m", method, strna(bad_field)); if (!FLAGS_SET(flags, VARLINK_METHOD_ONEWAY)) { r = varlink_errorb(v, VARLINK_ERROR_INVALID_PARAMETER, JSON_BUILD_OBJECT(JSON_BUILD_PAIR_STRING("parameter", bad_field))); if (r < 0) return r; } invalid = true; } } if (!invalid) { r = callback(v, parameters, flags, v->userdata); if (r < 0) { log_debug_errno(r, "Callback for %s returned error: %m", method); /* We got an error back from the callback. Propagate it to the client if the method call remains unanswered. */ if (v->state == VARLINK_PROCESSED_METHOD) r = 0; /* already processed */ else if (!FLAGS_SET(flags, VARLINK_METHOD_ONEWAY)) { r = varlink_error_errno(v, r); if (r < 0) return r; } } } } else if (!FLAGS_SET(flags, VARLINK_METHOD_ONEWAY)) { r = varlink_errorb(v, VARLINK_ERROR_METHOD_NOT_FOUND, JSON_BUILD_OBJECT(JSON_BUILD_PAIR("method", JSON_BUILD_STRING(method)))); if (r < 0) return r; } else r = 0; switch (v->state) { case VARLINK_PROCESSED_METHOD: /* Method call is fully processed */ case VARLINK_PROCESSING_METHOD_ONEWAY: /* ditto */ varlink_clear_current(v); varlink_set_state(v, VARLINK_IDLE_SERVER); break; case VARLINK_PROCESSING_METHOD: /* Method call wasn't replied to, will be replied to later */ varlink_set_state(v, VARLINK_PENDING_METHOD); break; case VARLINK_PROCESSING_METHOD_MORE: /* No reply for a "more" message was sent, more to come */ varlink_set_state(v, VARLINK_PENDING_METHOD_MORE); break; default: assert_not_reached(); } return r; invalid: r = -EINVAL; fail: varlink_set_state(v, VARLINK_PROCESSING_FAILURE); varlink_dispatch_local_error(v, VARLINK_ERROR_PROTOCOL); varlink_close(v); return r; } int varlink_process(Varlink *v) { int r; assert_return(v, -EINVAL); if (v->state == VARLINK_DISCONNECTED) return varlink_log_errno(v, SYNTHETIC_ERRNO(ENOTCONN), "Not connected."); varlink_ref(v); r = varlink_write(v); if (r < 0) varlink_log_errno(v, r, "Write failed: %m"); if (r != 0) goto finish; r = varlink_dispatch_reply(v); if (r < 0) varlink_log_errno(v, r, "Reply dispatch failed: %m"); if (r != 0) goto finish; r = varlink_dispatch_method(v); if (r < 0) varlink_log_errno(v, r, "Method dispatch failed: %m"); if (r != 0) goto finish; r = varlink_parse_message(v); if (r < 0) varlink_log_errno(v, r, "Message parsing failed: %m"); if (r != 0) goto finish; r = varlink_read(v); if (r < 0) varlink_log_errno(v, r, "Read failed: %m"); if (r != 0) goto finish; r = varlink_test_disconnect(v); assert(r >= 0); if (r != 0) goto finish; r = varlink_dispatch_disconnect(v); assert(r >= 0); if (r != 0) goto finish; r = varlink_test_timeout(v); assert(r >= 0); if (r != 0) goto finish; r = varlink_dispatch_timeout(v); assert(r >= 0); if (r != 0) goto finish; finish: if (r >= 0 && v->defer_event_source) { int q; /* If we did some processing, make sure we are called again soon */ q = sd_event_source_set_enabled(v->defer_event_source, r > 0 ? SD_EVENT_ON : SD_EVENT_OFF); if (q < 0) r = varlink_log_errno(v, q, "Failed to enable deferred event source: %m"); } if (r < 0) { if (VARLINK_STATE_IS_ALIVE(v->state)) /* Initiate disconnection */ varlink_set_state(v, VARLINK_PENDING_DISCONNECT); else /* We failed while disconnecting, in that case close right away */ varlink_close(v); } varlink_unref(v); return r; } static void handle_revents(Varlink *v, int revents) { assert(v); if (v->connecting) { /* If we have seen POLLOUT or POLLHUP on a socket we are asynchronously waiting a connect() * to complete on, we know we are ready. We don't read the connection error here though, * we'll get the error on the next read() or write(). */ if ((revents & (POLLOUT|POLLHUP)) == 0) return; varlink_log(v, "Asynchronous connection completed."); v->connecting = false; } else { /* Note that we don't care much about POLLIN/POLLOUT here, we'll just try reading and writing * what we can. However, we do care about POLLHUP to detect connection termination even if we * momentarily don't want to read nor write anything. */ if (!FLAGS_SET(revents, POLLHUP)) return; varlink_log(v, "Got POLLHUP from socket."); v->got_pollhup = true; } } int varlink_wait(Varlink *v, usec_t timeout) { int r, fd, events; usec_t t; assert_return(v, -EINVAL); if (v->state == VARLINK_DISCONNECTED) return varlink_log_errno(v, SYNTHETIC_ERRNO(ENOTCONN), "Not connected."); r = varlink_get_timeout(v, &t); if (r < 0) return r; if (t != USEC_INFINITY) { usec_t n; n = now(CLOCK_MONOTONIC); if (t < n) t = 0; else t = usec_sub_unsigned(t, n); } if (timeout != USEC_INFINITY && (t == USEC_INFINITY || timeout < t)) t = timeout; fd = varlink_get_fd(v); if (fd < 0) return fd; events = varlink_get_events(v); if (events < 0) return events; r = fd_wait_for_event(fd, events, t); if (ERRNO_IS_NEG_TRANSIENT(r)) /* Treat EINTR as not a timeout, but also nothing happened, and * the caller gets a chance to call back into us */ return 1; if (r <= 0) return r; handle_revents(v, r); return 1; } int varlink_is_idle(Varlink *v) { assert_return(v, -EINVAL); /* Returns true if there's nothing pending on the connection anymore, i.e. we processed all incoming * or outgoing messages fully, or finished disconnection */ return IN_SET(v->state, VARLINK_DISCONNECTED, VARLINK_IDLE_CLIENT, VARLINK_IDLE_SERVER); } int varlink_get_fd(Varlink *v) { assert_return(v, -EINVAL); if (v->state == VARLINK_DISCONNECTED) return varlink_log_errno(v, SYNTHETIC_ERRNO(ENOTCONN), "Not connected."); if (v->fd < 0) return varlink_log_errno(v, SYNTHETIC_ERRNO(EBADF), "No valid fd."); return v->fd; } int varlink_get_events(Varlink *v) { int ret = 0; assert_return(v, -EINVAL); if (v->state == VARLINK_DISCONNECTED) return varlink_log_errno(v, SYNTHETIC_ERRNO(ENOTCONN), "Not connected."); if (v->connecting) /* When processing an asynchronous connect(), we only wait for EPOLLOUT, which * tells us that the connection is now complete. Before that we should neither * write() or read() from the fd. */ return EPOLLOUT; if (!v->read_disconnected && IN_SET(v->state, VARLINK_AWAITING_REPLY, VARLINK_AWAITING_REPLY_MORE, VARLINK_CALLING, VARLINK_IDLE_SERVER) && !v->current && v->input_buffer_unscanned <= 0) ret |= EPOLLIN; if (!v->write_disconnected && (v->output_queue || v->output_buffer_size > 0)) ret |= EPOLLOUT; return ret; } int varlink_get_timeout(Varlink *v, usec_t *ret) { assert_return(v, -EINVAL); if (v->state == VARLINK_DISCONNECTED) return varlink_log_errno(v, SYNTHETIC_ERRNO(ENOTCONN), "Not connected."); if (IN_SET(v->state, VARLINK_AWAITING_REPLY, VARLINK_AWAITING_REPLY_MORE, VARLINK_CALLING) && v->timeout != USEC_INFINITY) { if (ret) *ret = usec_add(v->timestamp, v->timeout); return 1; } else { if (ret) *ret = USEC_INFINITY; return 0; } } int varlink_flush(Varlink *v) { int ret = 0, r; assert_return(v, -EINVAL); if (v->state == VARLINK_DISCONNECTED) return varlink_log_errno(v, SYNTHETIC_ERRNO(ENOTCONN), "Not connected."); for (;;) { if (v->output_buffer_size == 0) break; if (v->write_disconnected) return -ECONNRESET; r = varlink_write(v); if (r < 0) return r; if (r > 0) { ret = 1; continue; } r = fd_wait_for_event(v->fd, POLLOUT, USEC_INFINITY); if (ERRNO_IS_NEG_TRANSIENT(r)) continue; if (r < 0) return varlink_log_errno(v, r, "Poll failed on fd: %m"); assert(r > 0); handle_revents(v, r); } return ret; } static void varlink_detach_server(Varlink *v) { VarlinkServer *saved_server; assert(v); if (!v->server) return; if (v->server->by_uid && v->ucred_acquired && uid_is_valid(v->ucred.uid)) { unsigned c; c = PTR_TO_UINT(hashmap_get(v->server->by_uid, UID_TO_PTR(v->ucred.uid))); assert(c > 0); if (c == 1) (void) hashmap_remove(v->server->by_uid, UID_TO_PTR(v->ucred.uid)); else (void) hashmap_replace(v->server->by_uid, UID_TO_PTR(v->ucred.uid), UINT_TO_PTR(c - 1)); } assert(v->server->n_connections > 0); v->server->n_connections--; /* If this is a connection associated to a server, then let's disconnect the server and the * connection from each other. This drops the dangling reference that connect_callback() set up. But * before we release the references, let's call the disconnection callback if it is defined. */ saved_server = TAKE_PTR(v->server); if (saved_server->disconnect_callback) saved_server->disconnect_callback(saved_server, v, saved_server->userdata); varlink_server_test_exit_on_idle(saved_server); varlink_server_unref(saved_server); varlink_unref(v); } int varlink_close(Varlink *v) { assert_return(v, -EINVAL); if (v->state == VARLINK_DISCONNECTED) return 0; varlink_set_state(v, VARLINK_DISCONNECTED); /* Let's take a reference first, since varlink_detach_server() might drop the final (dangling) ref * which would destroy us before we can call varlink_clear() */ varlink_ref(v); varlink_detach_server(v); varlink_clear(v); varlink_unref(v); return 1; } Varlink* varlink_close_unref(Varlink *v) { if (!v) return NULL; (void) varlink_close(v); return varlink_unref(v); } Varlink* varlink_flush_close_unref(Varlink *v) { if (!v) return NULL; (void) varlink_flush(v); return varlink_close_unref(v); } static int varlink_format_json(Varlink *v, JsonVariant *m) { _cleanup_(erase_and_freep) char *text = NULL; int r; assert(v); assert(m); r = json_variant_format(m, 0, &text); if (r < 0) return r; assert(text[r] == '\0'); if (v->output_buffer_size + r + 1 > VARLINK_BUFFER_MAX) return -ENOBUFS; varlink_log(v, "Sending message: %s", text); if (v->output_buffer_size == 0) { free_and_replace(v->output_buffer, text); v->output_buffer_size = r + 1; v->output_buffer_index = 0; } else if (v->output_buffer_index == 0) { if (!GREEDY_REALLOC(v->output_buffer, v->output_buffer_size + r + 1)) return -ENOMEM; memcpy(v->output_buffer + v->output_buffer_size, text, r + 1); v->output_buffer_size += r + 1; } else { char *n; const size_t new_size = v->output_buffer_size + r + 1; n = new(char, new_size); if (!n) return -ENOMEM; memcpy(mempcpy(n, v->output_buffer + v->output_buffer_index, v->output_buffer_size), text, r + 1); free_and_replace(v->output_buffer, n); v->output_buffer_size = new_size; v->output_buffer_index = 0; } if (json_variant_is_sensitive(m)) v->output_buffer_sensitive = true; /* Propagate sensitive flag */ else text = mfree(text); /* No point in the erase_and_free() destructor declared above */ return 0; } static int varlink_enqueue_json(Varlink *v, JsonVariant *m) { VarlinkJsonQueueItem *q; assert(v); assert(m); /* If there are no file descriptors to be queued and no queue entries yet we can shortcut things and * append this entry directly to the output buffer */ if (v->n_pushed_fds == 0 && !v->output_queue) return varlink_format_json(v, m); /* Otherwise add a queue entry for this */ q = varlink_json_queue_item_new(m, v->pushed_fds, v->n_pushed_fds); if (!q) return -ENOMEM; v->n_pushed_fds = 0; /* fds now belong to the queue entry */ LIST_INSERT_AFTER(queue, v->output_queue, v->output_queue_tail, q); v->output_queue_tail = q; return 0; } static int varlink_format_queue(Varlink *v) { int r; assert(v); /* Takes entries out of the output queue and formats them into the output buffer. But only if this * would not corrupt our fd message boundaries */ while (v->output_queue) { _cleanup_free_ int *array = NULL; VarlinkJsonQueueItem *q = v->output_queue; if (v->n_output_fds > 0) /* unwritten fds? if we'd add more we'd corrupt the fd message boundaries, hence wait */ return 0; if (q->n_fds > 0) { array = newdup(int, q->fds, q->n_fds); if (!array) return -ENOMEM; } r = varlink_format_json(v, q->data); if (r < 0) return r; /* Take possession of the queue element's fds */ free(v->output_fds); v->output_fds = TAKE_PTR(array); v->n_output_fds = q->n_fds; q->n_fds = 0; LIST_REMOVE(queue, v->output_queue, q); if (!v->output_queue) v->output_queue_tail = NULL; varlink_json_queue_item_free(q); } return 0; } int varlink_send(Varlink *v, const char *method, JsonVariant *parameters) { _cleanup_(json_variant_unrefp) JsonVariant *m = NULL; int r; assert_return(v, -EINVAL); assert_return(method, -EINVAL); if (v->state == VARLINK_DISCONNECTED) return varlink_log_errno(v, SYNTHETIC_ERRNO(ENOTCONN), "Not connected."); /* We allow enqueuing multiple method calls at once! */ if (!IN_SET(v->state, VARLINK_IDLE_CLIENT, VARLINK_AWAITING_REPLY)) return varlink_log_errno(v, SYNTHETIC_ERRNO(EBUSY), "Connection busy."); r = varlink_sanitize_parameters(¶meters); if (r < 0) return varlink_log_errno(v, r, "Failed to sanitize parameters: %m"); r = json_build(&m, JSON_BUILD_OBJECT( JSON_BUILD_PAIR("method", JSON_BUILD_STRING(method)), JSON_BUILD_PAIR("parameters", JSON_BUILD_VARIANT(parameters)), JSON_BUILD_PAIR("oneway", JSON_BUILD_BOOLEAN(true)))); if (r < 0) return varlink_log_errno(v, r, "Failed to build json message: %m"); r = varlink_enqueue_json(v, m); if (r < 0) return varlink_log_errno(v, r, "Failed to enqueue json message: %m"); /* No state change here, this is one-way only after all */ v->timestamp = now(CLOCK_MONOTONIC); return 0; } int varlink_sendb(Varlink *v, const char *method, ...) { _cleanup_(json_variant_unrefp) JsonVariant *parameters = NULL; va_list ap; int r; assert_return(v, -EINVAL); va_start(ap, method); r = json_buildv(¶meters, ap); va_end(ap); if (r < 0) return varlink_log_errno(v, r, "Failed to build json message: %m"); return varlink_send(v, method, parameters); } int varlink_invoke(Varlink *v, const char *method, JsonVariant *parameters) { _cleanup_(json_variant_unrefp) JsonVariant *m = NULL; int r; assert_return(v, -EINVAL); assert_return(method, -EINVAL); if (v->state == VARLINK_DISCONNECTED) return varlink_log_errno(v, SYNTHETIC_ERRNO(ENOTCONN), "Not connected."); /* We allow enqueuing multiple method calls at once! */ if (!IN_SET(v->state, VARLINK_IDLE_CLIENT, VARLINK_AWAITING_REPLY)) return varlink_log_errno(v, SYNTHETIC_ERRNO(EBUSY), "Connection busy."); r = varlink_sanitize_parameters(¶meters); if (r < 0) return varlink_log_errno(v, r, "Failed to sanitize parameters: %m"); r = json_build(&m, JSON_BUILD_OBJECT( JSON_BUILD_PAIR("method", JSON_BUILD_STRING(method)), JSON_BUILD_PAIR("parameters", JSON_BUILD_VARIANT(parameters)))); if (r < 0) return varlink_log_errno(v, r, "Failed to build json message: %m"); r = varlink_enqueue_json(v, m); if (r < 0) return varlink_log_errno(v, r, "Failed to enqueue json message: %m"); varlink_set_state(v, VARLINK_AWAITING_REPLY); v->n_pending++; v->timestamp = now(CLOCK_MONOTONIC); return 0; } int varlink_invokeb(Varlink *v, const char *method, ...) { _cleanup_(json_variant_unrefp) JsonVariant *parameters = NULL; va_list ap; int r; assert_return(v, -EINVAL); va_start(ap, method); r = json_buildv(¶meters, ap); va_end(ap); if (r < 0) return varlink_log_errno(v, r, "Failed to build json message: %m"); return varlink_invoke(v, method, parameters); } int varlink_observe(Varlink *v, const char *method, JsonVariant *parameters) { _cleanup_(json_variant_unrefp) JsonVariant *m = NULL; int r; assert_return(v, -EINVAL); assert_return(method, -EINVAL); if (v->state == VARLINK_DISCONNECTED) return varlink_log_errno(v, SYNTHETIC_ERRNO(ENOTCONN), "Not connected."); /* Note that we don't allow enqueuing multiple method calls when we are in more/continues mode! We * thus insist on an idle client here. */ if (v->state != VARLINK_IDLE_CLIENT) return varlink_log_errno(v, SYNTHETIC_ERRNO(EBUSY), "Connection busy."); r = varlink_sanitize_parameters(¶meters); if (r < 0) return varlink_log_errno(v, r, "Failed to sanitize parameters: %m"); r = json_build(&m, JSON_BUILD_OBJECT( JSON_BUILD_PAIR("method", JSON_BUILD_STRING(method)), JSON_BUILD_PAIR("parameters", JSON_BUILD_VARIANT(parameters)), JSON_BUILD_PAIR("more", JSON_BUILD_BOOLEAN(true)))); if (r < 0) return varlink_log_errno(v, r, "Failed to build json message: %m"); r = varlink_enqueue_json(v, m); if (r < 0) return varlink_log_errno(v, r, "Failed to enqueue json message: %m"); varlink_set_state(v, VARLINK_AWAITING_REPLY_MORE); v->n_pending++; v->timestamp = now(CLOCK_MONOTONIC); return 0; } int varlink_observeb(Varlink *v, const char *method, ...) { _cleanup_(json_variant_unrefp) JsonVariant *parameters = NULL; va_list ap; int r; assert_return(v, -EINVAL); va_start(ap, method); r = json_buildv(¶meters, ap); va_end(ap); if (r < 0) return varlink_log_errno(v, r, "Failed to build json message: %m"); return varlink_observe(v, method, parameters); } int varlink_call( Varlink *v, const char *method, JsonVariant *parameters, JsonVariant **ret_parameters, const char **ret_error_id, VarlinkReplyFlags *ret_flags) { _cleanup_(json_variant_unrefp) JsonVariant *m = NULL; int r; assert_return(v, -EINVAL); assert_return(method, -EINVAL); if (v->state == VARLINK_DISCONNECTED) return varlink_log_errno(v, SYNTHETIC_ERRNO(ENOTCONN), "Not connected."); if (v->state != VARLINK_IDLE_CLIENT) return varlink_log_errno(v, SYNTHETIC_ERRNO(EBUSY), "Connection busy."); assert(v->n_pending == 0); /* n_pending can't be > 0 if we are in VARLINK_IDLE_CLIENT state */ /* If there was still a reply pinned from a previous call, now it's the time to get rid of it, so * that we can assign a new reply shortly. */ varlink_clear_current(v); r = varlink_sanitize_parameters(¶meters); if (r < 0) return varlink_log_errno(v, r, "Failed to sanitize parameters: %m"); r = json_build(&m, JSON_BUILD_OBJECT( JSON_BUILD_PAIR("method", JSON_BUILD_STRING(method)), JSON_BUILD_PAIR("parameters", JSON_BUILD_VARIANT(parameters)))); if (r < 0) return varlink_log_errno(v, r, "Failed to build json message: %m"); r = varlink_enqueue_json(v, m); if (r < 0) return varlink_log_errno(v, r, "Failed to enqueue json message: %m"); varlink_set_state(v, VARLINK_CALLING); v->n_pending++; v->timestamp = now(CLOCK_MONOTONIC); while (v->state == VARLINK_CALLING) { r = varlink_process(v); if (r < 0) return r; if (r > 0) continue; r = varlink_wait(v, USEC_INFINITY); if (r < 0) return r; } switch (v->state) { case VARLINK_CALLED: assert(v->current); varlink_set_state(v, VARLINK_IDLE_CLIENT); assert(v->n_pending == 1); v->n_pending--; if (ret_parameters) *ret_parameters = json_variant_by_key(v->current, "parameters"); if (ret_error_id) *ret_error_id = json_variant_string(json_variant_by_key(v->current, "error")); if (ret_flags) *ret_flags = 0; return 1; case VARLINK_PENDING_DISCONNECT: case VARLINK_DISCONNECTED: return varlink_log_errno(v, SYNTHETIC_ERRNO(ECONNRESET), "Connection was closed."); case VARLINK_PENDING_TIMEOUT: return varlink_log_errno(v, SYNTHETIC_ERRNO(ETIME), "Connection timed out."); default: assert_not_reached(); } } int varlink_callb( Varlink *v, const char *method, JsonVariant **ret_parameters, const char **ret_error_id, VarlinkReplyFlags *ret_flags, ...) { _cleanup_(json_variant_unrefp) JsonVariant *parameters = NULL; va_list ap; int r; assert_return(v, -EINVAL); va_start(ap, ret_flags); r = json_buildv(¶meters, ap); va_end(ap); if (r < 0) return varlink_log_errno(v, r, "Failed to build json message: %m"); return varlink_call(v, method, parameters, ret_parameters, ret_error_id, ret_flags); } static void varlink_collect_context_free(VarlinkCollectContext *cc) { assert(cc); json_variant_unref(cc->parameters); free((char *)cc->error_id); } static int collect_callback( Varlink *v, JsonVariant *parameters, const char *error_id, VarlinkReplyFlags flags, void *userdata) { VarlinkCollectContext *context = ASSERT_PTR(userdata); int r; assert(v); context->flags = flags; /* If we hit an error, we will drop all collected replies and just return the error_id and flags in varlink_collect() */ if (error_id) { context->error_id = error_id; return 0; } r = json_variant_append_array(&context->parameters, parameters); if (r < 0) return varlink_log_errno(v, r, "Failed to append JSON object to array: %m"); return 1; } int varlink_collect( Varlink *v, const char *method, JsonVariant *parameters, JsonVariant **ret_parameters, const char **ret_error_id, VarlinkReplyFlags *ret_flags) { _cleanup_(varlink_collect_context_free) VarlinkCollectContext context = {}; int r; assert_return(v, -EINVAL); assert_return(method, -EINVAL); if (v->state == VARLINK_DISCONNECTED) return varlink_log_errno(v, SYNTHETIC_ERRNO(ENOTCONN), "Not connected."); if (v->state != VARLINK_IDLE_CLIENT) return varlink_log_errno(v, SYNTHETIC_ERRNO(EBUSY), "Connection busy."); assert(v->n_pending == 0); /* n_pending can't be > 0 if we are in VARLINK_IDLE_CLIENT state */ /* If there was still a reply pinned from a previous call, now it's the time to get rid of it, so * that we can assign a new reply shortly. */ varlink_clear_current(v); r = varlink_bind_reply(v, collect_callback); if (r < 0) return varlink_log_errno(v, r, "Failed to bind collect callback"); varlink_set_userdata(v, &context); r = varlink_observe(v, method, parameters); if (r < 0) return varlink_log_errno(v, r, "Failed to collect varlink method: %m"); while (v->state == VARLINK_AWAITING_REPLY_MORE) { r = varlink_process(v); if (r < 0) return r; /* If we get an error from any of the replies, return immediately with just the error_id and flags*/ if (context.error_id) { if (ret_error_id) *ret_error_id = TAKE_PTR(context.error_id); if (ret_flags) *ret_flags = context.flags; return 0; } if (r > 0) continue; r = varlink_wait(v, USEC_INFINITY); if (r < 0) return r; } switch (v->state) { case VARLINK_IDLE_CLIENT: break; case VARLINK_PENDING_DISCONNECT: case VARLINK_DISCONNECTED: return varlink_log_errno(v, SYNTHETIC_ERRNO(ECONNRESET), "Connection was closed."); case VARLINK_PENDING_TIMEOUT: return varlink_log_errno(v, SYNTHETIC_ERRNO(ETIME), "Connection timed out."); default: assert_not_reached(); } if (ret_parameters) *ret_parameters = TAKE_PTR(context.parameters); if (ret_error_id) *ret_error_id = TAKE_PTR(context.error_id); if (ret_flags) *ret_flags = context.flags; return 1; } int varlink_collectb( Varlink *v, const char *method, JsonVariant **ret_parameters, const char **ret_error_id, VarlinkReplyFlags *ret_flags, ...) { _cleanup_(json_variant_unrefp) JsonVariant *parameters = NULL; va_list ap; int r; assert_return(v, -EINVAL); va_start(ap, ret_flags); r = json_buildv(¶meters, ap); va_end(ap); if (r < 0) return varlink_log_errno(v, r, "Failed to build json message: %m"); return varlink_collect(v, method, parameters, ret_parameters, ret_error_id, ret_flags); } int varlink_reply(Varlink *v, JsonVariant *parameters) { _cleanup_(json_variant_unrefp) JsonVariant *m = NULL; int r; assert_return(v, -EINVAL); if (v->state == VARLINK_DISCONNECTED) return -ENOTCONN; if (!IN_SET(v->state, VARLINK_PROCESSING_METHOD, VARLINK_PROCESSING_METHOD_MORE, VARLINK_PENDING_METHOD, VARLINK_PENDING_METHOD_MORE)) return -EBUSY; r = varlink_sanitize_parameters(¶meters); if (r < 0) return varlink_log_errno(v, r, "Failed to sanitize parameters: %m"); r = json_build(&m, JSON_BUILD_OBJECT(JSON_BUILD_PAIR("parameters", JSON_BUILD_VARIANT(parameters)))); if (r < 0) return varlink_log_errno(v, r, "Failed to build json message: %m"); if (v->current_method) { const char *bad_field = NULL; r = varlink_idl_validate_method_reply(v->current_method, parameters, &bad_field); if (r < 0) log_debug_errno(r, "Return parameters for method reply %s() didn't pass validation on field '%s', ignoring: %m", v->current_method->name, strna(bad_field)); } r = varlink_enqueue_json(v, m); if (r < 0) return varlink_log_errno(v, r, "Failed to enqueue json message: %m"); if (IN_SET(v->state, VARLINK_PENDING_METHOD, VARLINK_PENDING_METHOD_MORE)) { /* We just replied to a method call that was let hanging for a while (i.e. we were outside of * the varlink_dispatch_method() stack frame), which means with this reply we are ready to * process further messages. */ varlink_clear_current(v); varlink_set_state(v, VARLINK_IDLE_SERVER); } else /* We replied to a method call from within the varlink_dispatch_method() stack frame), which * means we should it handle the rest of the state engine. */ varlink_set_state(v, VARLINK_PROCESSED_METHOD); return 1; } int varlink_replyb(Varlink *v, ...) { _cleanup_(json_variant_unrefp) JsonVariant *parameters = NULL; va_list ap; int r; assert_return(v, -EINVAL); va_start(ap, v); r = json_buildv(¶meters, ap); va_end(ap); if (r < 0) return r; return varlink_reply(v, parameters); } int varlink_error(Varlink *v, const char *error_id, JsonVariant *parameters) { _cleanup_(json_variant_unrefp) JsonVariant *m = NULL; int r; assert_return(v, -EINVAL); assert_return(error_id, -EINVAL); if (v->state == VARLINK_DISCONNECTED) return varlink_log_errno(v, SYNTHETIC_ERRNO(ENOTCONN), "Not connected."); if (!IN_SET(v->state, VARLINK_PROCESSING_METHOD, VARLINK_PROCESSING_METHOD_MORE, VARLINK_PENDING_METHOD, VARLINK_PENDING_METHOD_MORE)) return varlink_log_errno(v, SYNTHETIC_ERRNO(EBUSY), "Connection busy."); /* Reset the list of pushed file descriptors before sending an error reply. We do this here to * simplify code that puts together a complex reply message with fds, and half-way something * fails. In that case the pushed fds need to be flushed out again. Under the assumption that it * never makes sense to send fds along with errors we simply flush them out here beforehand, so that * the callers don't need to do this explicitly. */ varlink_reset_fds(v); r = varlink_sanitize_parameters(¶meters); if (r < 0) return varlink_log_errno(v, r, "Failed to sanitize parameters: %m"); r = json_build(&m, JSON_BUILD_OBJECT( JSON_BUILD_PAIR("error", JSON_BUILD_STRING(error_id)), JSON_BUILD_PAIR("parameters", JSON_BUILD_VARIANT(parameters)))); if (r < 0) return varlink_log_errno(v, r, "Failed to build json message: %m"); VarlinkSymbol *symbol = hashmap_get(v->server->symbols, error_id); if (!symbol) log_debug("No interface description defined for error '%s', not validating.", error_id); else { const char *bad_field = NULL; r = varlink_idl_validate_error(symbol, parameters, &bad_field); if (r < 0) log_debug_errno(r, "Parameters for error %s didn't pass validation on field '%s', ignoring: %m", error_id, strna(bad_field)); } r = varlink_enqueue_json(v, m); if (r < 0) return varlink_log_errno(v, r, "Failed to enqueue json message: %m"); if (IN_SET(v->state, VARLINK_PENDING_METHOD, VARLINK_PENDING_METHOD_MORE)) { varlink_clear_current(v); varlink_set_state(v, VARLINK_IDLE_SERVER); } else varlink_set_state(v, VARLINK_PROCESSED_METHOD); return 1; } int varlink_errorb(Varlink *v, const char *error_id, ...) { _cleanup_(json_variant_unrefp) JsonVariant *parameters = NULL; va_list ap; int r; assert_return(v, -EINVAL); assert_return(error_id, -EINVAL); va_start(ap, error_id); r = json_buildv(¶meters, ap); va_end(ap); if (r < 0) return varlink_log_errno(v, r, "Failed to build json message: %m"); return varlink_error(v, error_id, parameters); } int varlink_error_invalid_parameter(Varlink *v, JsonVariant *parameters) { int r; assert_return(v, -EINVAL); assert_return(parameters, -EINVAL); /* We expect to be called in one of two ways: the 'parameters' argument is a string variant in which * case it is the parameter key name that is invalid. Or the 'parameters' argument is an object * variant in which case we'll pull out the first key. The latter mode is useful in functions that * don't expect any arguments. */ /* varlink_error(...) expects a json object as the third parameter. Passing a string variant causes * parameter sanitization to fail, and it returns -EINVAL. */ if (json_variant_is_string(parameters)) { _cleanup_(json_variant_unrefp) JsonVariant *parameters_obj = NULL; r = json_build(¶meters_obj, JSON_BUILD_OBJECT( JSON_BUILD_PAIR("parameter", JSON_BUILD_VARIANT(parameters)))); if (r < 0) return r; return varlink_error(v, VARLINK_ERROR_INVALID_PARAMETER, parameters_obj); } if (json_variant_is_object(parameters) && json_variant_elements(parameters) > 0) { _cleanup_(json_variant_unrefp) JsonVariant *parameters_obj = NULL; r = json_build(¶meters_obj, JSON_BUILD_OBJECT( JSON_BUILD_PAIR("parameter", JSON_BUILD_VARIANT(json_variant_by_index(parameters, 0))))); if (r < 0) return r; return varlink_error(v, VARLINK_ERROR_INVALID_PARAMETER, parameters_obj); } return -EINVAL; } int varlink_error_errno(Varlink *v, int error) { return varlink_errorb( v, VARLINK_ERROR_SYSTEM, JSON_BUILD_OBJECT(JSON_BUILD_PAIR("errno", JSON_BUILD_INTEGER(abs(error))))); } int varlink_notify(Varlink *v, JsonVariant *parameters) { _cleanup_(json_variant_unrefp) JsonVariant *m = NULL; int r; assert_return(v, -EINVAL); if (v->state == VARLINK_DISCONNECTED) return varlink_log_errno(v, SYNTHETIC_ERRNO(ENOTCONN), "Not connected."); /* If we want to reply with a notify connection but the caller didn't set "more", then return an * error indicating that we expected to be called with "more" set */ if (IN_SET(v->state, VARLINK_PROCESSING_METHOD, VARLINK_PENDING_METHOD)) return varlink_error(v, VARLINK_ERROR_EXPECTED_MORE, NULL); if (!IN_SET(v->state, VARLINK_PROCESSING_METHOD_MORE, VARLINK_PENDING_METHOD_MORE)) return varlink_log_errno(v, SYNTHETIC_ERRNO(EBUSY), "Connection busy."); r = varlink_sanitize_parameters(¶meters); if (r < 0) return varlink_log_errno(v, r, "Failed to sanitize parameters: %m"); r = json_build(&m, JSON_BUILD_OBJECT( JSON_BUILD_PAIR("parameters", JSON_BUILD_VARIANT(parameters)), JSON_BUILD_PAIR("continues", JSON_BUILD_BOOLEAN(true)))); if (r < 0) return varlink_log_errno(v, r, "Failed to build json message: %m"); if (v->current_method) { const char *bad_field = NULL; r = varlink_idl_validate_method_reply(v->current_method, parameters, &bad_field); if (r < 0) log_debug_errno(r, "Return parameters for method reply %s() didn't pass validation on field '%s', ignoring: %m", v->current_method->name, strna(bad_field)); } r = varlink_enqueue_json(v, m); if (r < 0) return varlink_log_errno(v, r, "Failed to enqueue json message: %m"); /* No state change, as more is coming */ return 1; } int varlink_notifyb(Varlink *v, ...) { _cleanup_(json_variant_unrefp) JsonVariant *parameters = NULL; va_list ap; int r; assert_return(v, -EINVAL); va_start(ap, v); r = json_buildv(¶meters, ap); va_end(ap); if (r < 0) return varlink_log_errno(v, r, "Failed to build json message: %m"); return varlink_notify(v, parameters); } int varlink_dispatch(Varlink *v, JsonVariant *parameters, const JsonDispatch table[], void *userdata) { const char *bad_field = NULL; int r; assert_return(v, -EINVAL); assert_return(table, -EINVAL); /* A wrapper around json_dispatch_full() that returns a nice InvalidParameter error if we hit a problem with some field. */ r = json_dispatch_full(parameters, table, /* bad= */ NULL, /* flags= */ 0, userdata, &bad_field); if (r < 0) { if (bad_field) return varlink_errorb(v, VARLINK_ERROR_INVALID_PARAMETER, JSON_BUILD_OBJECT(JSON_BUILD_PAIR("parameter", JSON_BUILD_STRING(bad_field)))); return r; } return 0; } int varlink_bind_reply(Varlink *v, VarlinkReply callback) { assert_return(v, -EINVAL); if (callback && v->reply_callback && callback != v->reply_callback) return varlink_log_errno(v, SYNTHETIC_ERRNO(EBUSY), "A different callback was already set."); v->reply_callback = callback; return 0; } void* varlink_set_userdata(Varlink *v, void *userdata) { void *old; assert_return(v, NULL); old = v->userdata; v->userdata = userdata; return old; } void* varlink_get_userdata(Varlink *v) { assert_return(v, NULL); return v->userdata; } static int varlink_acquire_ucred(Varlink *v) { int r; assert(v); if (v->ucred_acquired) return 0; r = getpeercred(v->fd, &v->ucred); if (r < 0) return r; v->ucred_acquired = true; return 0; } int varlink_get_peer_uid(Varlink *v, uid_t *ret) { int r; assert_return(v, -EINVAL); assert_return(ret, -EINVAL); r = varlink_acquire_ucred(v); if (r < 0) return varlink_log_errno(v, r, "Failed to acquire credentials: %m"); if (!uid_is_valid(v->ucred.uid)) return varlink_log_errno(v, SYNTHETIC_ERRNO(ENODATA), "Peer uid is invalid."); *ret = v->ucred.uid; return 0; } int varlink_get_peer_pid(Varlink *v, pid_t *ret) { int r; assert_return(v, -EINVAL); assert_return(ret, -EINVAL); r = varlink_acquire_ucred(v); if (r < 0) return varlink_log_errno(v, r, "Failed to acquire credentials: %m"); if (!pid_is_valid(v->ucred.pid)) return varlink_log_errno(v, SYNTHETIC_ERRNO(ENODATA), "Peer uid is invalid."); *ret = v->ucred.pid; return 0; } int varlink_set_relative_timeout(Varlink *v, usec_t timeout) { assert_return(v, -EINVAL); assert_return(timeout > 0, -EINVAL); v->timeout = timeout; return 0; } VarlinkServer *varlink_get_server(Varlink *v) { assert_return(v, NULL); return v->server; } int varlink_set_description(Varlink *v, const char *description) { assert_return(v, -EINVAL); return free_and_strdup(&v->description, description); } static int io_callback(sd_event_source *s, int fd, uint32_t revents, void *userdata) { Varlink *v = ASSERT_PTR(userdata); assert(s); handle_revents(v, revents); (void) varlink_process(v); return 1; } static int time_callback(sd_event_source *s, uint64_t usec, void *userdata) { Varlink *v = ASSERT_PTR(userdata); assert(s); (void) varlink_process(v); return 1; } static int defer_callback(sd_event_source *s, void *userdata) { Varlink *v = ASSERT_PTR(userdata); assert(s); (void) varlink_process(v); return 1; } static int prepare_callback(sd_event_source *s, void *userdata) { Varlink *v = ASSERT_PTR(userdata); int r, e; usec_t until; bool have_timeout; assert(s); e = varlink_get_events(v); if (e < 0) return e; r = sd_event_source_set_io_events(v->io_event_source, e); if (r < 0) return varlink_log_errno(v, r, "Failed to set source events: %m"); r = varlink_get_timeout(v, &until); if (r < 0) return r; have_timeout = r > 0; if (have_timeout) { r = sd_event_source_set_time(v->time_event_source, until); if (r < 0) return varlink_log_errno(v, r, "Failed to set source time: %m"); } r = sd_event_source_set_enabled(v->time_event_source, have_timeout ? SD_EVENT_ON : SD_EVENT_OFF); if (r < 0) return varlink_log_errno(v, r, "Failed to enable event source: %m"); return 1; } static int quit_callback(sd_event_source *event, void *userdata) { Varlink *v = ASSERT_PTR(userdata); assert(event); varlink_flush(v); varlink_close(v); return 1; } int varlink_attach_event(Varlink *v, sd_event *e, int64_t priority) { int r; assert_return(v, -EINVAL); assert_return(!v->event, -EBUSY); if (e) v->event = sd_event_ref(e); else { r = sd_event_default(&v->event); if (r < 0) return varlink_log_errno(v, r, "Failed to create event source: %m"); } r = sd_event_add_time(v->event, &v->time_event_source, CLOCK_MONOTONIC, 0, 0, time_callback, v); if (r < 0) goto fail; r = sd_event_source_set_priority(v->time_event_source, priority); if (r < 0) goto fail; (void) sd_event_source_set_description(v->time_event_source, "varlink-time"); r = sd_event_add_exit(v->event, &v->quit_event_source, quit_callback, v); if (r < 0) goto fail; r = sd_event_source_set_priority(v->quit_event_source, priority); if (r < 0) goto fail; (void) sd_event_source_set_description(v->quit_event_source, "varlink-quit"); r = sd_event_add_io(v->event, &v->io_event_source, v->fd, 0, io_callback, v); if (r < 0) goto fail; r = sd_event_source_set_prepare(v->io_event_source, prepare_callback); if (r < 0) goto fail; r = sd_event_source_set_priority(v->io_event_source, priority); if (r < 0) goto fail; (void) sd_event_source_set_description(v->io_event_source, "varlink-io"); r = sd_event_add_defer(v->event, &v->defer_event_source, defer_callback, v); if (r < 0) goto fail; r = sd_event_source_set_priority(v->defer_event_source, priority); if (r < 0) goto fail; (void) sd_event_source_set_description(v->defer_event_source, "varlink-defer"); return 0; fail: varlink_log_errno(v, r, "Failed to setup event source: %m"); varlink_detach_event(v); return r; } void varlink_detach_event(Varlink *v) { if (!v) return; varlink_detach_event_sources(v); v->event = sd_event_unref(v->event); } sd_event *varlink_get_event(Varlink *v) { assert_return(v, NULL); return v->event; } int varlink_push_fd(Varlink *v, int fd) { int i; assert_return(v, -EINVAL); assert_return(fd >= 0, -EBADF); /* Takes an fd to send along with the *next* varlink message sent via this varlink connection. This * takes ownership of the specified fd. Use varlink_dup_fd() below to duplicate the fd first. */ if (!v->allow_fd_passing_output) return -EPERM; if (v->n_pushed_fds >= SCM_MAX_FD) /* Kernel doesn't support more than 253 fds per message, refuse early hence */ return -ENOBUFS; if (!GREEDY_REALLOC(v->pushed_fds, v->n_pushed_fds + 1)) return -ENOMEM; i = (int) v->n_pushed_fds; v->pushed_fds[v->n_pushed_fds++] = fd; return i; } int varlink_dup_fd(Varlink *v, int fd) { _cleanup_close_ int dp = -1; int r; assert_return(v, -EINVAL); assert_return(fd >= 0, -EBADF); /* Like varlink_push_fd() but duplicates the specified fd instead of taking possession of it */ dp = fcntl(fd, F_DUPFD_CLOEXEC, 3); if (dp < 0) return -errno; r = varlink_push_fd(v, dp); if (r < 0) return r; TAKE_FD(dp); return r; } int varlink_reset_fds(Varlink *v) { assert_return(v, -EINVAL); /* Closes all currently pending fds to send. This may be used whenever the caller is in the process * of putting together a message with fds, and then eventually something fails and they need to * rollback the fds. Note that this is implicitly called whenever an error reply is sent, see above. */ close_many(v->output_fds, v->n_output_fds); v->n_output_fds = 0; return 0; } int varlink_peek_fd(Varlink *v, size_t i) { assert_return(v, -EINVAL); /* Returns one of the file descriptors that were received along with the current message. This does * not duplicate the fd nor invalidate it, it hence remains in our possession. */ if (!v->allow_fd_passing_input) return -EPERM; if (i >= v->n_input_fds) return -ENXIO; return v->input_fds[i]; } int varlink_take_fd(Varlink *v, size_t i) { assert_return(v, -EINVAL); /* Similar to varlink_peek_fd() but the file descriptor's ownership is passed to the caller, and * we'll invalidate the reference to it under our possession. If called twice in a row will return * -EBADF */ if (!v->allow_fd_passing_input) return -EPERM; if (i >= v->n_input_fds) return -ENXIO; return TAKE_FD(v->input_fds[i]); } static int verify_unix_socket(Varlink *v) { assert(v); /* Returns: * • 0 if this is an AF_UNIX socket * • -ENOTSOCK if this is not a socket at all * • -ENOMEDIUM if this is a socket, but not an AF_UNIX socket * * Reminder: * • v->af is < 0 if we haven't checked what kind of address family the thing is yet. * • v->af == AF_UNSPEC if we checked but it's not a socket * • otherwise: v->af contains the address family we determined */ if (v->af < 0) { struct stat st; if (fstat(v->fd, &st) < 0) return -errno; if (!S_ISSOCK(st.st_mode)) { v->af = AF_UNSPEC; return -ENOTSOCK; } v->af = socket_get_family(v->fd); if (v->af < 0) return v->af; } return v->af == AF_UNIX ? 0 : v->af == AF_UNSPEC ? -ENOTSOCK : -ENOMEDIUM; } int varlink_set_allow_fd_passing_input(Varlink *v, bool b) { int r; assert_return(v, -EINVAL); if (v->allow_fd_passing_input == b) return 0; if (!b) { v->allow_fd_passing_input = false; return 1; } r = verify_unix_socket(v); if (r < 0) return r; v->allow_fd_passing_input = true; return 0; } int varlink_set_allow_fd_passing_output(Varlink *v, bool b) { int r; assert_return(v, -EINVAL); if (v->allow_fd_passing_output == b) return 0; if (!b) { v->allow_fd_passing_output = false; return 1; } r = verify_unix_socket(v); if (r < 0) return r; v->allow_fd_passing_output = true; return 0; } int varlink_server_new(VarlinkServer **ret, VarlinkServerFlags flags) { _cleanup_(varlink_server_unrefp) VarlinkServer *s = NULL; int r; assert_return(ret, -EINVAL); assert_return((flags & ~_VARLINK_SERVER_FLAGS_ALL) == 0, -EINVAL); s = new(VarlinkServer, 1); if (!s) return log_oom_debug(); *s = (VarlinkServer) { .n_ref = 1, .flags = flags, .connections_max = varlink_server_connections_max(NULL), .connections_per_uid_max = varlink_server_connections_per_uid_max(NULL), }; r = varlink_server_add_interface_many( s, &vl_interface_io_systemd, &vl_interface_org_varlink_service); if (r < 0) return r; *ret = TAKE_PTR(s); return 0; } static VarlinkServer* varlink_server_destroy(VarlinkServer *s) { char *m; if (!s) return NULL; varlink_server_shutdown(s); while ((m = hashmap_steal_first_key(s->methods))) free(m); hashmap_free(s->methods); hashmap_free(s->interfaces); hashmap_free(s->symbols); hashmap_free(s->by_uid); sd_event_unref(s->event); free(s->description); return mfree(s); } DEFINE_TRIVIAL_REF_UNREF_FUNC(VarlinkServer, varlink_server, varlink_server_destroy); static int validate_connection(VarlinkServer *server, const struct ucred *ucred) { int allowed = -1; assert(server); assert(ucred); if (FLAGS_SET(server->flags, VARLINK_SERVER_ROOT_ONLY)) allowed = ucred->uid == 0; if (FLAGS_SET(server->flags, VARLINK_SERVER_MYSELF_ONLY)) allowed = allowed > 0 || ucred->uid == getuid(); if (allowed == 0) { /* Allow access when it is explicitly allowed or when neither * VARLINK_SERVER_ROOT_ONLY nor VARLINK_SERVER_MYSELF_ONLY are specified. */ varlink_server_log(server, "Unprivileged client attempted connection, refusing."); return 0; } if (server->n_connections >= server->connections_max) { varlink_server_log(server, "Connection limit of %u reached, refusing.", server->connections_max); return 0; } if (FLAGS_SET(server->flags, VARLINK_SERVER_ACCOUNT_UID)) { unsigned c; if (!uid_is_valid(ucred->uid)) { varlink_server_log(server, "Client with invalid UID attempted connection, refusing."); return 0; } c = PTR_TO_UINT(hashmap_get(server->by_uid, UID_TO_PTR(ucred->uid))); if (c >= server->connections_per_uid_max) { varlink_server_log(server, "Per-UID connection limit of %u reached, refusing.", server->connections_per_uid_max); return 0; } } return 1; } static int count_connection(VarlinkServer *server, const struct ucred *ucred) { unsigned c; int r; assert(server); assert(ucred); server->n_connections++; if (FLAGS_SET(server->flags, VARLINK_SERVER_ACCOUNT_UID)) { r = hashmap_ensure_allocated(&server->by_uid, NULL); if (r < 0) return log_debug_errno(r, "Failed to allocate UID hash table: %m"); c = PTR_TO_UINT(hashmap_get(server->by_uid, UID_TO_PTR(ucred->uid))); varlink_server_log(server, "Connections of user " UID_FMT ": %u (of %u max)", ucred->uid, c, server->connections_per_uid_max); r = hashmap_replace(server->by_uid, UID_TO_PTR(ucred->uid), UINT_TO_PTR(c + 1)); if (r < 0) return log_debug_errno(r, "Failed to increment counter in UID hash table: %m"); } return 0; } int varlink_server_add_connection(VarlinkServer *server, int fd, Varlink **ret) { _cleanup_(varlink_unrefp) Varlink *v = NULL; struct ucred ucred = UCRED_INVALID; bool ucred_acquired; int r; assert_return(server, -EINVAL); assert_return(fd >= 0, -EBADF); if ((server->flags & (VARLINK_SERVER_ROOT_ONLY|VARLINK_SERVER_ACCOUNT_UID)) != 0) { r = getpeercred(fd, &ucred); if (r < 0) return varlink_server_log_errno(server, r, "Failed to acquire peer credentials of incoming socket, refusing: %m"); ucred_acquired = true; r = validate_connection(server, &ucred); if (r < 0) return r; if (r == 0) return -EPERM; } else ucred_acquired = false; r = varlink_new(&v); if (r < 0) return varlink_server_log_errno(server, r, "Failed to allocate connection object: %m"); r = count_connection(server, &ucred); if (r < 0) return r; v->fd = fd; if (server->flags & VARLINK_SERVER_INHERIT_USERDATA) v->userdata = server->userdata; if (ucred_acquired) { v->ucred = ucred; v->ucred_acquired = true; } _cleanup_free_ char *desc = NULL; if (asprintf(&desc, "%s-%i", server->description ?: "varlink", v->fd) >= 0) v->description = TAKE_PTR(desc); /* Link up the server and the connection, and take reference in both directions. Note that the * reference on the connection is left dangling. It will be dropped when the connection is closed, * which happens in varlink_close(), including in the event loop quit callback. */ v->server = varlink_server_ref(server); varlink_ref(v); varlink_set_state(v, VARLINK_IDLE_SERVER); if (server->event) { r = varlink_attach_event(v, server->event, server->event_priority); if (r < 0) { varlink_log_errno(v, r, "Failed to attach new connection: %m"); v->fd = -EBADF; /* take the fd out of the connection again */ varlink_close(v); return r; } } if (ret) *ret = v; return 0; } static VarlinkServerSocket *varlink_server_socket_free(VarlinkServerSocket *ss) { if (!ss) return NULL; free(ss->address); return mfree(ss); } DEFINE_TRIVIAL_CLEANUP_FUNC(VarlinkServerSocket *, varlink_server_socket_free); static int connect_callback(sd_event_source *source, int fd, uint32_t revents, void *userdata) { VarlinkServerSocket *ss = ASSERT_PTR(userdata); _cleanup_close_ int cfd = -EBADF; Varlink *v = NULL; int r; assert(source); varlink_server_log(ss->server, "New incoming connection."); cfd = accept4(fd, NULL, NULL, SOCK_NONBLOCK|SOCK_CLOEXEC); if (cfd < 0) { if (ERRNO_IS_ACCEPT_AGAIN(errno)) return 0; return varlink_server_log_errno(ss->server, errno, "Failed to accept incoming socket: %m"); } r = varlink_server_add_connection(ss->server, cfd, &v); if (r < 0) return 0; TAKE_FD(cfd); if (ss->server->connect_callback) { r = ss->server->connect_callback(ss->server, v, ss->server->userdata); if (r < 0) { varlink_log_errno(v, r, "Connection callback returned error, disconnecting client: %m"); varlink_close(v); return 0; } } return 0; } static int varlink_server_create_listen_fd_socket(VarlinkServer *s, int fd, VarlinkServerSocket **ret_ss) { _cleanup_(varlink_server_socket_freep) VarlinkServerSocket *ss = NULL; int r; assert(s); assert(fd >= 0); assert(ret_ss); ss = new(VarlinkServerSocket, 1); if (!ss) return log_oom_debug(); *ss = (VarlinkServerSocket) { .server = s, .fd = fd, }; if (s->event) { r = sd_event_add_io(s->event, &ss->event_source, fd, EPOLLIN, connect_callback, ss); if (r < 0) return r; r = sd_event_source_set_priority(ss->event_source, s->event_priority); if (r < 0) return r; } *ret_ss = TAKE_PTR(ss); return 0; } int varlink_server_listen_fd(VarlinkServer *s, int fd) { _cleanup_(varlink_server_socket_freep) VarlinkServerSocket *ss = NULL; int r; assert_return(s, -EINVAL); assert_return(fd >= 0, -EBADF); r = fd_nonblock(fd, true); if (r < 0) return r; r = fd_cloexec(fd, true); if (r < 0) return r; r = varlink_server_create_listen_fd_socket(s, fd, &ss); if (r < 0) return r; LIST_PREPEND(sockets, s->sockets, TAKE_PTR(ss)); return 0; } int varlink_server_listen_address(VarlinkServer *s, const char *address, mode_t m) { _cleanup_(varlink_server_socket_freep) VarlinkServerSocket *ss = NULL; union sockaddr_union sockaddr; socklen_t sockaddr_len; _cleanup_close_ int fd = -EBADF; int r; assert_return(s, -EINVAL); assert_return(address, -EINVAL); assert_return((m & ~0777) == 0, -EINVAL); r = sockaddr_un_set_path(&sockaddr.un, address); if (r < 0) return r; sockaddr_len = r; fd = socket(AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0); if (fd < 0) return -errno; fd = fd_move_above_stdio(fd); (void) sockaddr_un_unlink(&sockaddr.un); WITH_UMASK(~m & 0777) { r = mac_selinux_bind(fd, &sockaddr.sa, sockaddr_len); if (r < 0) return r; } if (listen(fd, SOMAXCONN_DELUXE) < 0) return -errno; r = varlink_server_create_listen_fd_socket(s, fd, &ss); if (r < 0) return r; r = free_and_strdup(&ss->address, address); if (r < 0) return r; LIST_PREPEND(sockets, s->sockets, TAKE_PTR(ss)); TAKE_FD(fd); return 0; } int varlink_server_listen_auto(VarlinkServer *s) { _cleanup_strv_free_ char **names = NULL; int r, m, n = 0; assert_return(s, -EINVAL); /* Adds all passed fds marked as "varlink" to our varlink server. These fds can either refer to a * listening socket or to a connection socket. * * See https://varlink.org/#activation for the environment variables this is backed by and the * recommended "varlink" identifier in $LISTEN_FDNAMES. */ m = sd_listen_fds_with_names(/* unset_environment= */ false, &names); if (m < 0) return m; for (int i = 0; i < m; i++) { int b, fd; socklen_t l = sizeof(b); if (!streq(names[i], "varlink")) continue; fd = SD_LISTEN_FDS_START + i; if (getsockopt(fd, SOL_SOCKET, SO_ACCEPTCONN, &b, &l) < 0) return -errno; assert(l == sizeof(b)); if (b) /* Listening socket? */ r = varlink_server_listen_fd(s, fd); else /* Otherwise assume connection socket */ r = varlink_server_add_connection(s, fd, NULL); if (r < 0) return r; n++; } return n; } void* varlink_server_set_userdata(VarlinkServer *s, void *userdata) { void *ret; assert_return(s, NULL); ret = s->userdata; s->userdata = userdata; return ret; } void* varlink_server_get_userdata(VarlinkServer *s) { assert_return(s, NULL); return s->userdata; } int varlink_server_loop_auto(VarlinkServer *server) { _cleanup_(sd_event_unrefp) sd_event *event = NULL; int r; assert_return(server, -EINVAL); assert_return(!server->event, -EBUSY); /* Runs a Varlink service event loop populated with a passed fd. Exits on the last connection. */ r = sd_event_new(&event); if (r < 0) return r; r = varlink_server_set_exit_on_idle(server, true); if (r < 0) return r; r = varlink_server_attach_event(server, event, 0); if (r < 0) return r; r = varlink_server_listen_auto(server); if (r < 0) return r; return sd_event_loop(event); } static VarlinkServerSocket* varlink_server_socket_destroy(VarlinkServerSocket *ss) { if (!ss) return NULL; if (ss->server) LIST_REMOVE(sockets, ss->server->sockets, ss); sd_event_source_disable_unref(ss->event_source); free(ss->address); safe_close(ss->fd); return mfree(ss); } int varlink_server_shutdown(VarlinkServer *s) { assert_return(s, -EINVAL); while (s->sockets) varlink_server_socket_destroy(s->sockets); return 0; } static void varlink_server_test_exit_on_idle(VarlinkServer *s) { assert(s); if (s->exit_on_idle && s->event && s->n_connections == 0) (void) sd_event_exit(s->event, 0); } int varlink_server_set_exit_on_idle(VarlinkServer *s, bool b) { assert_return(s, -EINVAL); s->exit_on_idle = b; varlink_server_test_exit_on_idle(s); return 0; } static int varlink_server_add_socket_event_source(VarlinkServer *s, VarlinkServerSocket *ss, int64_t priority) { _cleanup_(sd_event_source_unrefp) sd_event_source *es = NULL; int r; assert(s); assert(s->event); assert(ss); assert(ss->fd >= 0); assert(!ss->event_source); r = sd_event_add_io(s->event, &es, ss->fd, EPOLLIN, connect_callback, ss); if (r < 0) return r; r = sd_event_source_set_priority(es, priority); if (r < 0) return r; ss->event_source = TAKE_PTR(es); return 0; } int varlink_server_attach_event(VarlinkServer *s, sd_event *e, int64_t priority) { int r; assert_return(s, -EINVAL); assert_return(!s->event, -EBUSY); if (e) s->event = sd_event_ref(e); else { r = sd_event_default(&s->event); if (r < 0) return r; } LIST_FOREACH(sockets, ss, s->sockets) { r = varlink_server_add_socket_event_source(s, ss, priority); if (r < 0) goto fail; } s->event_priority = priority; return 0; fail: varlink_server_detach_event(s); return r; } int varlink_server_detach_event(VarlinkServer *s) { assert_return(s, -EINVAL); LIST_FOREACH(sockets, ss, s->sockets) ss->event_source = sd_event_source_disable_unref(ss->event_source); sd_event_unref(s->event); return 0; } sd_event *varlink_server_get_event(VarlinkServer *s) { assert_return(s, NULL); return s->event; } static bool varlink_symbol_in_interface(const char *method, const char *interface) { const char *p; assert(method); assert(interface); p = startswith(method, interface); if (!p) return false; if (*p != '.') return false; return !strchr(p+1, '.'); } int varlink_server_bind_method(VarlinkServer *s, const char *method, VarlinkMethod callback) { _cleanup_free_ char *m = NULL; int r; assert_return(s, -EINVAL); assert_return(method, -EINVAL); assert_return(callback, -EINVAL); if (varlink_symbol_in_interface(method, "org.varlink.service") || varlink_symbol_in_interface(method, "io.systemd")) return log_debug_errno(SYNTHETIC_ERRNO(EEXIST), "Cannot bind server to '%s'.", method); m = strdup(method); if (!m) return log_oom_debug(); r = hashmap_ensure_put(&s->methods, &string_hash_ops, m, callback); if (r == -ENOMEM) return log_oom_debug(); if (r < 0) return log_debug_errno(r, "Failed to register callback: %m"); if (r > 0) TAKE_PTR(m); return 0; } int varlink_server_bind_method_many_internal(VarlinkServer *s, ...) { va_list ap; int r = 0; assert_return(s, -EINVAL); va_start(ap, s); for (;;) { VarlinkMethod callback; const char *method; method = va_arg(ap, const char *); if (!method) break; callback = va_arg(ap, VarlinkMethod); r = varlink_server_bind_method(s, method, callback); if (r < 0) break; } va_end(ap); return r; } int varlink_server_bind_connect(VarlinkServer *s, VarlinkConnect callback) { assert_return(s, -EINVAL); if (callback && s->connect_callback && callback != s->connect_callback) return log_debug_errno(SYNTHETIC_ERRNO(EBUSY), "A different callback was already set."); s->connect_callback = callback; return 0; } int varlink_server_bind_disconnect(VarlinkServer *s, VarlinkDisconnect callback) { assert_return(s, -EINVAL); if (callback && s->disconnect_callback && callback != s->disconnect_callback) return log_debug_errno(SYNTHETIC_ERRNO(EBUSY), "A different callback was already set."); s->disconnect_callback = callback; return 0; } int varlink_server_add_interface(VarlinkServer *s, const VarlinkInterface *interface) { int r; assert_return(s, -EINVAL); assert_return(interface, -EINVAL); assert_return(interface->name, -EINVAL); if (hashmap_contains(s->interfaces, interface->name)) return log_debug_errno(SYNTHETIC_ERRNO(EEXIST), "Duplicate registration of interface '%s'.", interface->name); r = hashmap_ensure_put(&s->interfaces, &string_hash_ops, interface->name, (void*) interface); if (r < 0) return r; for (const VarlinkSymbol *const*symbol = interface->symbols; *symbol; symbol++) { _cleanup_free_ char *j = NULL; /* We only ever want to validate method calls/replies and errors against the interface * definitions, hence don't bother with the type symbols */ if (!IN_SET((*symbol)->symbol_type, VARLINK_METHOD, VARLINK_ERROR)) continue; j = strjoin(interface->name, ".", (*symbol)->name); if (!j) return -ENOMEM; r = hashmap_ensure_put(&s->symbols, &string_hash_ops_free, j, (void*) *symbol); if (r < 0) return r; TAKE_PTR(j); } return 0; } int varlink_server_add_interface_many_internal(VarlinkServer *s, ...) { va_list ap; int r = 0; assert_return(s, -EINVAL); va_start(ap, s); for (;;) { const VarlinkInterface *interface = va_arg(ap, const VarlinkInterface*); if (!interface) break; r = varlink_server_add_interface(s, interface); if (r < 0) break; } va_end(ap); return r; } unsigned varlink_server_connections_max(VarlinkServer *s) { int dts; /* If a server is specified, return the setting for that server, otherwise the default value */ if (s) return s->connections_max; dts = getdtablesize(); assert_se(dts > 0); /* Make sure we never use up more than ¾th of RLIMIT_NOFILE for IPC */ if (VARLINK_DEFAULT_CONNECTIONS_MAX > (unsigned) dts / 4 * 3) return dts / 4 * 3; return VARLINK_DEFAULT_CONNECTIONS_MAX; } unsigned varlink_server_connections_per_uid_max(VarlinkServer *s) { unsigned m; if (s) return s->connections_per_uid_max; /* Make sure to never use up more than ¾th of available connections for a single user */ m = varlink_server_connections_max(NULL); if (VARLINK_DEFAULT_CONNECTIONS_PER_UID_MAX > m) return m / 4 * 3; return VARLINK_DEFAULT_CONNECTIONS_PER_UID_MAX; } int varlink_server_set_connections_per_uid_max(VarlinkServer *s, unsigned m) { assert_return(s, -EINVAL); assert_return(m > 0, -EINVAL); s->connections_per_uid_max = m; return 0; } int varlink_server_set_connections_max(VarlinkServer *s, unsigned m) { assert_return(s, -EINVAL); assert_return(m > 0, -EINVAL); s->connections_max = m; return 0; } unsigned varlink_server_current_connections(VarlinkServer *s) { assert_return(s, UINT_MAX); return s->n_connections; } int varlink_server_set_description(VarlinkServer *s, const char *description) { assert_return(s, -EINVAL); return free_and_strdup(&s->description, description); } int varlink_server_serialize(VarlinkServer *s, FILE *f, FDSet *fds) { assert(f); assert(fds); if (!s) return 0; LIST_FOREACH(sockets, ss, s->sockets) { int copy; assert(ss->address); assert(ss->fd >= 0); fprintf(f, "varlink-server-socket-address=%s", ss->address); /* If we fail to serialize the fd, it will be considered an error during deserialization */ copy = fdset_put_dup(fds, ss->fd); if (copy < 0) return copy; fprintf(f, " varlink-server-socket-fd=%i", copy); fputc('\n', f); } return 0; } int varlink_server_deserialize_one(VarlinkServer *s, const char *value, FDSet *fds) { _cleanup_(varlink_server_socket_freep) VarlinkServerSocket *ss = NULL; _cleanup_free_ char *address = NULL; const char *v = ASSERT_PTR(value); int r, fd = -EBADF; char *buf; size_t n; assert(s); assert(fds); n = strcspn(v, " "); address = strndup(v, n); if (!address) return log_oom_debug(); if (v[n] != ' ') return log_debug_errno(SYNTHETIC_ERRNO(EINVAL), "Failed to deserialize VarlinkServerSocket: %s: %m", value); v = startswith(v + n + 1, "varlink-server-socket-fd="); if (!v) return log_debug_errno(SYNTHETIC_ERRNO(EINVAL), "Failed to deserialize VarlinkServerSocket fd %s: %m", value); n = strcspn(v, " "); buf = strndupa_safe(v, n); fd = parse_fd(buf); if (fd < 0) return log_debug_errno(fd, "Unable to parse VarlinkServerSocket varlink-server-socket-fd=%s: %m", buf); if (!fdset_contains(fds, fd)) return log_debug_errno(SYNTHETIC_ERRNO(EBADF), "VarlinkServerSocket varlink-server-socket-fd= has unknown fd %d: %m", fd); ss = new(VarlinkServerSocket, 1); if (!ss) return log_oom_debug(); *ss = (VarlinkServerSocket) { .server = s, .address = TAKE_PTR(address), .fd = fdset_remove(fds, fd), }; r = varlink_server_add_socket_event_source(s, ss, SD_EVENT_PRIORITY_NORMAL); if (r < 0) return log_debug_errno(r, "Failed to add VarlinkServerSocket event source to the event loop: %m"); LIST_PREPEND(sockets, s->sockets, TAKE_PTR(ss)); return 0; } int varlink_invocation(VarlinkInvocationFlags flags) { _cleanup_strv_free_ char **names = NULL; int r, b; socklen_t l = sizeof(b); /* Returns true if this is a "pure" varlink server invocation, i.e. with one fd passed. */ r = sd_listen_fds_with_names(/* unset_environment= */ false, &names); if (r < 0) return r; if (r == 0) return false; if (r > 1) return -ETOOMANYREFS; if (!strv_equal(names, STRV_MAKE("varlink"))) return false; if (FLAGS_SET(flags, VARLINK_ALLOW_LISTEN|VARLINK_ALLOW_ACCEPT)) /* Both flags set? Then allow everything */ return true; if ((flags & (VARLINK_ALLOW_LISTEN|VARLINK_ALLOW_ACCEPT)) == 0) /* Neither is set, then fail */ return -EISCONN; if (getsockopt(SD_LISTEN_FDS_START, SOL_SOCKET, SO_ACCEPTCONN, &b, &l) < 0) return -errno; assert(l == sizeof(b)); if (!FLAGS_SET(flags, b ? VARLINK_ALLOW_LISTEN : VARLINK_ALLOW_ACCEPT)) return -EISCONN; return true; }