/* SPDX-License-Identifier: LGPL-2.1-or-later */ #include #include "alloc-util.h" #include "errno-util.h" #include "fd-util.h" #include "hashmap.h" #include "io-util.h" #include "list.h" #include "process-util.h" #include "selinux-util.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" #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) 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_allocated; size_t input_buffer_index; size_t input_buffer_size; size_t input_buffer_unscanned; char *output_buffer; /* valid data starts at output_buffer_index, ends at output_buffer_index+output_buffer_size */ size_t output_buffer_allocated; size_t output_buffer_index; size_t output_buffer_size; VarlinkReply reply_callback; JsonVariant *current; JsonVariant *reply; struct ucred ucred; bool ucred_acquired:1; bool write_disconnected:1; bool read_disconnected:1; bool prefer_read_write:1; bool got_pollhup:1; 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; }; typedef struct VarlinkServerSocket VarlinkServerSocket; struct VarlinkServerSocket { VarlinkServer *server; int fd; char *address; sd_event_source *event_source; LIST_FIELDS(VarlinkServerSocket, sockets); }; struct VarlinkServer { unsigned n_ref; VarlinkServerFlags flags; LIST_HEAD(VarlinkServerSocket, sockets); Hashmap *methods; VarlinkConnect connect_callback; VarlinkDisconnect disconnect_callback; sd_event *event; int64_t event_priority; unsigned n_connections; Hashmap *by_uid; void *userdata; char *description; unsigned connections_max; unsigned connections_per_uid_max; }; 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 inline const char *varlink_description(Varlink *v) { return strna(v ? v->description : NULL); } static inline const char *varlink_server_description(VarlinkServer *s) { return strna(s ? s->description : NULL); } 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, "varlink: setting state %s", varlink_state_to_string(state)); else varlink_log(v, "varlink: changing state %s → %s", varlink_state_to_string(v->state), 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 = -1, .state = _VARLINK_STATE_INVALID, .ucred.uid = UID_INVALID, .ucred.gid = GID_INVALID, .timestamp = USEC_INFINITY, .timeout = VARLINK_DEFAULT_TIMEOUT_USEC }; *ret = v; return 0; } int varlink_connect_address(Varlink **ret, const char *address) { _cleanup_(varlink_unrefp) Varlink *v = NULL; union sockaddr_union sockaddr; socklen_t sockaddr_len; int r; assert_return(ret, -EINVAL); assert_return(address, -EINVAL); r = sockaddr_un_set_path(&sockaddr.un, address); if (r < 0) return log_debug_errno(r, "Failed to set socket address '%s': %m", address); sockaddr_len = r; 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); if (connect(v->fd, &sockaddr.sa, sockaddr_len) < 0) { if (!IN_SET(errno, EAGAIN, EINPROGRESS)) return log_debug_errno(errno, "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_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; 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(Varlink *v) { assert(v); varlink_detach_event_sources(v); v->fd = safe_close(v->fd); v->input_buffer = mfree(v->input_buffer); v->output_buffer = mfree(v->output_buffer); v->current = json_variant_unref(v->current); v->reply = json_variant_unref(v->reply); v->event = sd_event_unref(v->event); } 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 (IN_SET(v->state, VARLINK_IDLE_CLIENT) && (v->write_disconnected || v->got_pollhup)) goto disconnect; /* The server is still expecting to write more, but its write end is disconnected and it got a POLLHUP * (i.e. from a disconnected client), so disconnect. */ if (IN_SET(v->state, VARLINK_PENDING_METHOD, VARLINK_PENDING_METHOD_MORE) && v->write_disconnected && 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; 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->output_buffer_size == 0) return 0; if (v->write_disconnected) return 0; assert(v->fd >= 0); /* 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; } v->output_buffer_size -= n; if (v->output_buffer_size == 0) v->output_buffer_index = 0; else v->output_buffer_index += n; v->timestamp = now(CLOCK_MONOTONIC); return 1; } static int varlink_read(Varlink *v) { size_t rs; ssize_t n; 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 (v->input_buffer_allocated <= 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_allocated, 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_allocated = v->input_buffer_size + add; v->input_buffer_index = 0; } } rs = v->input_buffer_allocated - (v->input_buffer_index + v->input_buffer_size); bool prefer_read = v->prefer_read_write; if (!prefer_read) { n = recv(v->fd, v->input_buffer + v->input_buffer_index + v->input_buffer_size, rs, MSG_DONTWAIT); if (n < 0 && errno == ENOTSOCK) prefer_read = v->prefer_read_write = true; } if (prefer_read) n = read(v->fd, v->input_buffer + v->input_buffer_index + v->input_buffer_size, 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 */ v->read_disconnected = true; return 1; } 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 <= v->input_buffer_allocated); 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) { 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); else 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)) 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"); } v->current = json_variant_unref(v->current); 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 varlink_dispatch_method(Varlink *v) { _cleanup_(json_variant_unrefp) JsonVariant *parameters = NULL; VarlinkMethodFlags flags = 0; const char *method = NULL, *error; 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)) 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); if (STR_IN_SET(method, "org.varlink.service.GetInfo", "org.varlink.service.GetInterface")) { /* For now, we don't implement a single of varlink's own methods */ callback = NULL; error = VARLINK_ERROR_METHOD_NOT_IMPLEMENTED; } else if (startswith(method, "org.varlink.service.")) { callback = NULL; error = VARLINK_ERROR_METHOD_NOT_FOUND; } else { callback = hashmap_get(v->server->methods, method); error = VARLINK_ERROR_METHOD_NOT_FOUND; } if (callback) { 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 (!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)) { assert(error); r = varlink_errorb(v, error, JSON_BUILD_OBJECT(JSON_BUILD_PAIR("method", JSON_BUILD_STRING(method)))); if (r < 0) return r; } switch (v->state) { case VARLINK_PROCESSED_METHOD: /* Method call is fully processed */ case VARLINK_PROCESSING_METHOD_ONEWAY: /* ditto */ v->current = json_variant_unref(v->current); 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("Unexpected state"); } 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, "Anynchronous 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 (r <= 0) return r; handle_revents(v, r); return 1; } 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_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 (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_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 ref from the * disconnect callback, which would invalidate the pointer we are holding 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; /* A reference is given to us to be destroyed. But when calling varlink_close(), a callback might * also drop a reference. We allow this, and will hold a temporary reference to the object to make * sure that the object still exists when control returns to us. If there's just one reference * remaining after varlink_close(), even though there were at least two right before, we'll handle * that gracefully instead of crashing. * * In other words, this call drops the donated reference, but if the internal call to varlink_close() * dropped a reference to, we don't drop the reference afain. This allows the caller to say: * global_object->varlink = varlink_close_unref(global_object->varlink); * even though there is some callback which has access to global_object and may drop the reference * stored in global_object->varlink. Without this step, the same code would have to be written as: * Varlink *t = TAKE_PTR(global_object->varlink); * varlink_close_unref(t); */ /* n_ref >= 1 */ varlink_ref(v); /* n_ref >= 2 */ varlink_close(v); /* n_ref >= 1 */ if (v->n_ref > 1) v->n_ref--; /* n_ref >= 1 */ return varlink_unref(v); } Varlink* varlink_flush_close_unref(Varlink *v) { if (v) varlink_flush(v); return varlink_close_unref(v); } static int varlink_enqueue_json(Varlink *v, JsonVariant *m) { _cleanup_free_ 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 = v->output_buffer_allocated = r + 1; v->output_buffer_index = 0; } else if (v->output_buffer_index == 0) { if (!GREEDY_REALLOC(v->output_buffer, v->output_buffer_allocated, 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_allocated = v->output_buffer_size = new_size; v->output_buffer_index = 0; } 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 (!IN_SET(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 */ 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); json_variant_unref(v->reply); v->reply = TAKE_PTR(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->reply, "parameters"); if (ret_error_id) *ret_error_id = json_variant_string(json_variant_by_key(v->reply, "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("Unexpected state after method call."); } } 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); } 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"); 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. */ v->current = json_variant_unref(v->current); 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."); 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"); 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)) { v->current = json_variant_unref(v->current); 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) { 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. */ if (json_variant_is_string(parameters)) return varlink_error(v, VARLINK_ERROR_INVALID_PARAMETER, parameters); if (json_variant_is_object(parameters) && json_variant_elements(parameters) > 0) return varlink_error(v, VARLINK_ERROR_INVALID_PARAMETER, json_variant_by_index(parameters, 0)); 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 (!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"); 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_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 = userdata; assert(s); assert(v); 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 = userdata; assert(s); assert(v); (void) varlink_process(v); return 1; } static int defer_callback(sd_event_source *s, void *userdata) { Varlink *v = userdata; assert(s); assert(v); (void) varlink_process(v); return 1; } static int prepare_callback(sd_event_source *s, void *userdata) { Varlink *v = userdata; int r, e; usec_t until; bool have_timeout; assert(s); assert(v); 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 = userdata; assert(event); assert(v); 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_server_new(VarlinkServer **ret, VarlinkServerFlags flags) { VarlinkServer *s; 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), }; *ret = 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->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, 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; bool ucred_acquired; struct ucred ucred; 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; } (void) asprintf(&v->description, "%s-%i", server->description ?: "varlink", v->fd); /* 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 = -1; /* take the fd out of the connection again */ varlink_close(v); return r; } } if (ret) *ret = v; return 0; } static int connect_callback(sd_event_source *source, int fd, uint32_t revents, void *userdata) { VarlinkServerSocket *ss = userdata; _cleanup_close_ int cfd = -1; Varlink *v = NULL; int r; assert(source); assert(ss); 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; } int varlink_server_listen_fd(VarlinkServer *s, int fd) { _cleanup_free_ VarlinkServerSocket *ss = NULL; int r; assert_return(s, -EINVAL); assert_return(fd >= 0, -EBADF); r = fd_nonblock(fd, true); if (r < 0) return r; 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; } LIST_PREPEND(sockets, s->sockets, TAKE_PTR(ss)); return 0; } int varlink_server_listen_address(VarlinkServer *s, const char *address, mode_t m) { union sockaddr_union sockaddr; socklen_t sockaddr_len; _cleanup_close_ int fd = -1; 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); RUN_WITH_UMASK(~m & 0777) { r = mac_selinux_bind(fd, &sockaddr.sa, sockaddr_len); if (r < 0) return r; } if (listen(fd, SOMAXCONN) < 0) return -errno; r = varlink_server_listen_fd(s, fd); if (r < 0) return r; TAKE_FD(fd); return 0; } 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; } 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; } int varlink_server_attach_event(VarlinkServer *s, sd_event *e, int64_t priority) { VarlinkServerSocket *ss; 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) { assert(!ss->event_source); r = sd_event_add_io(s->event, &ss->event_source, ss->fd, EPOLLIN, connect_callback, ss); if (r < 0) goto fail; r = sd_event_source_set_priority(ss->event_source, 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) { VarlinkServerSocket *ss; assert_return(s, -EINVAL); LIST_FOREACH(sockets, ss, s->sockets) { if (!ss->event_source) continue; (void) sd_event_source_set_enabled(ss->event_source, SD_EVENT_OFF); ss->event_source = sd_event_source_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; } 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 (startswith(method, "org.varlink.service.")) 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; } 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); }