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src.rivoreo.one / systemd-stable / v247-rc2 / . / src / shared / varlink.c
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/* SPDX-License-Identifier: LGPL-2.1-or-later */
#include <sys/poll.h>
#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 = -1
} 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 r;
sockaddr_len = r;
r = varlink_new(&v);
if (r < 0)
return r;
v->fd = socket(AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
if (v->fd < 0)
return -errno;
v->fd = fd_move_above_stdio(v->fd);
if (connect(v->fd, &sockaddr.sa, sockaddr_len) < 0) {
if (!IN_SET(errno, EAGAIN, EINPROGRESS))
return -errno;
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 r;
}
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 r;
r = varlink_new(&v);
if (r < 0)
return r;
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 */
if (!v->prefer_read_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)
v->prefer_read_write = true;
}
if (v->prefer_read_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);
if (!v->prefer_read_write) {
n = recv(v->fd, v->input_buffer + v->input_buffer_index + v->input_buffer_size, rs, MSG_DONTWAIT);
if (n < 0 && errno == ENOTSOCK)
v->prefer_read_write = true;
}
if (v->prefer_read_write)
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(&parameters);
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(&parameters);
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 -ENOTCONN;
varlink_ref(v);
r = varlink_write(v);
if (r != 0)
goto finish;
r = varlink_dispatch_reply(v);
if (r != 0)
goto finish;
r = varlink_dispatch_method(v);
if (r != 0)
goto finish;
r = varlink_parse_message(v);
if (r != 0)
goto finish;
r = varlink_read(v);
if (r != 0)
goto finish;
r = varlink_test_disconnect(v);
if (r != 0)
goto finish;
r = varlink_dispatch_disconnect(v);
if (r != 0)
goto finish;
r = varlink_test_timeout(v);
if (r != 0)
goto finish;
r = varlink_dispatch_timeout(v);
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 = q;
}
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 -ENOTCONN;
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 -ENOTCONN;
if (v->fd < 0)
return -EBADF;
return v->fd;
}
int varlink_get_events(Varlink *v) {
int ret = 0;
assert_return(v, -EINVAL);
if (v->state == VARLINK_DISCONNECTED)
return -ENOTCONN;
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 -ENOTCONN;
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 -ENOTCONN;
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 r;
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 (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);
(void) varlink_close(v);
return varlink_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 -ENOTCONN;
/* We allow enqueuing multiple method calls at once! */
if (!IN_SET(v->state, VARLINK_IDLE_CLIENT, VARLINK_AWAITING_REPLY))
return -EBUSY;
r = varlink_sanitize_parameters(&parameters);
if (r < 0)
return r;
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 r;
r = varlink_enqueue_json(v, m);
if (r < 0)
return r;
/* 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(&parameters, ap);
va_end(ap);
if (r < 0)
return r;
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 -ENOTCONN;
/* We allow enqueuing multiple method calls at once! */
if (!IN_SET(v->state, VARLINK_IDLE_CLIENT, VARLINK_AWAITING_REPLY))
return -EBUSY;
r = varlink_sanitize_parameters(&parameters);
if (r < 0)
return r;
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 r;
r = varlink_enqueue_json(v, m);
if (r < 0)
return r;
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(&parameters, ap);
va_end(ap);
if (r < 0)
return r;
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 -ENOTCONN;
/* 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 -EBUSY;
r = varlink_sanitize_parameters(&parameters);
if (r < 0)
return r;
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 r;
r = varlink_enqueue_json(v, m);
if (r < 0)
return r;
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(&parameters, ap);
va_end(ap);
if (r < 0)
return r;
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 -ENOTCONN;
if (!IN_SET(v->state, VARLINK_IDLE_CLIENT))
return -EBUSY;
assert(v->n_pending == 0); /* n_pending can't be > 0 if we are in VARLINK_IDLE_CLIENT state */
r = varlink_sanitize_parameters(&parameters);
if (r < 0)
return r;
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 r;
r = varlink_enqueue_json(v, m);
if (r < 0)
return r;
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 -ECONNRESET;
case VARLINK_PENDING_TIMEOUT:
return -ETIME;
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(&parameters, ap);
va_end(ap);
if (r < 0)
return r;
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(&parameters);
if (r < 0)
return r;
r = json_build(&m, JSON_BUILD_OBJECT(JSON_BUILD_PAIR("parameters", JSON_BUILD_VARIANT(parameters))));
if (r < 0)
return r;
r = varlink_enqueue_json(v, m);
if (r < 0)
return r;
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(&parameters, 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 -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(&parameters);
if (r < 0)
return r;
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 r;
r = varlink_enqueue_json(v, m);
if (r < 0)
return r;
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(&parameters, ap);
va_end(ap);
if (r < 0)
return r;
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 -ENOTCONN;
if (!IN_SET(v->state, VARLINK_PROCESSING_METHOD_MORE, VARLINK_PENDING_METHOD_MORE))
return -EBUSY;
r = varlink_sanitize_parameters(&parameters);
if (r < 0)
return r;
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 r;
r = varlink_enqueue_json(v, m);
if (r < 0)
return r;
/* 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(&parameters, ap);
va_end(ap);
if (r < 0)
return r;
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 -EBUSY;
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 r;
if (!uid_is_valid(v->ucred.uid))
return -ENODATA;
*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 r;
if (!pid_is_valid(v->ucred.pid))
return -ENODATA;
*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 r;
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 r;
}
r = sd_event_source_set_enabled(v->time_event_source, have_timeout ? SD_EVENT_ON : SD_EVENT_OFF);
if (r < 0)
return r;
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 r;
}
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_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 -ENOMEM;
*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;
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 -ENOMEM;
*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) {
char *m;
int r;
assert_return(s, -EINVAL);
assert_return(method, -EINVAL);
assert_return(callback, -EINVAL);
if (startswith(method, "org.varlink.service."))
return -EEXIST;
r = hashmap_ensure_allocated(&s->methods, &string_hash_ops);
if (r < 0)
return r;
m = strdup(method);
if (!m)
return -ENOMEM;
r = hashmap_put(s->methods, m, callback);
if (r < 0) {
free(m);
return r;
}
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 -EBUSY;
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 -EBUSY;
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);
}