/* SPDX-License-Identifier: LGPL-2.1+ */
/***
***/
#include <endian.h>
#include <poll.h>
#include <stdlib.h>
#include <unistd.h>
#include "sd-bus.h"
#include "sd-daemon.h"
#include "alloc-util.h"
#include "bus-internal.h"
#include "bus-message.h"
#include "bus-socket.h"
#include "fd-util.h"
#include "format-util.h"
#include "fs-util.h"
#include "hexdecoct.h"
#include "io-util.h"
#include "macro.h"
#include "missing.h"
#include "path-util.h"
#include "process-util.h"
#include "selinux-util.h"
#include "signal-util.h"
#include "stdio-util.h"
#include "string-util.h"
#include "user-util.h"
#include "utf8.h"
#include "util.h"
#define SNDBUF_SIZE (8*1024*1024)
static void iovec_advance(struct iovec iov[], unsigned *idx, size_t size) {
while (size > 0) {
struct iovec *i = iov + *idx;
if (i->iov_len > size) {
i->iov_base = (uint8_t*) i->iov_base + size;
i->iov_len -= size;
return;
}
size -= i->iov_len;
i->iov_base = NULL;
i->iov_len = 0;
(*idx)++;
}
}
static int append_iovec(sd_bus_message *m, const void *p, size_t sz) {
assert(m);
assert(p);
assert(sz > 0);
m->iovec[m->n_iovec].iov_base = (void*) p;
m->iovec[m->n_iovec].iov_len = sz;
m->n_iovec++;
return 0;
}
static int bus_message_setup_iovec(sd_bus_message *m) {
struct bus_body_part *part;
unsigned n, i;
int r;
assert(m);
assert(m->sealed);
if (m->n_iovec > 0)
return 0;
assert(!m->iovec);
n = 1 + m->n_body_parts;
if (n < ELEMENTSOF(m->iovec_fixed))
m->iovec = m->iovec_fixed;
else {
m->iovec = new(struct iovec, n);
if (!m->iovec) {
r = -ENOMEM;
goto fail;
}
}
r = append_iovec(m, m->header, BUS_MESSAGE_BODY_BEGIN(m));
if (r < 0)
goto fail;
MESSAGE_FOREACH_PART(part, i, m) {
r = bus_body_part_map(part);
if (r < 0)
goto fail;
r = append_iovec(m, part->data, part->size);
if (r < 0)
goto fail;
}
assert(n == m->n_iovec);
return 0;
fail:
m->poisoned = true;
return r;
}
bool bus_socket_auth_needs_write(sd_bus *b) {
unsigned i;
if (b->auth_index >= ELEMENTSOF(b->auth_iovec))
return false;
for (i = b->auth_index; i < ELEMENTSOF(b->auth_iovec); i++) {
struct iovec *j = b->auth_iovec + i;
if (j->iov_len > 0)
return true;
}
return false;
}
static int bus_socket_write_auth(sd_bus *b) {
ssize_t k;
assert(b);
assert(b->state == BUS_AUTHENTICATING);
if (!bus_socket_auth_needs_write(b))
return 0;
if (b->prefer_writev)
k = writev(b->output_fd, b->auth_iovec + b->auth_index, ELEMENTSOF(b->auth_iovec) - b->auth_index);
else {
struct msghdr mh;
zero(mh);
mh.msg_iov = b->auth_iovec + b->auth_index;
mh.msg_iovlen = ELEMENTSOF(b->auth_iovec) - b->auth_index;
k = sendmsg(b->output_fd, &mh, MSG_DONTWAIT|MSG_NOSIGNAL);
if (k < 0 && errno == ENOTSOCK) {
b->prefer_writev = true;
k = writev(b->output_fd, b->auth_iovec + b->auth_index, ELEMENTSOF(b->auth_iovec) - b->auth_index);
}
}
if (k < 0)
return errno == EAGAIN ? 0 : -errno;
iovec_advance(b->auth_iovec, &b->auth_index, (size_t) k);
return 1;
}
static int bus_socket_auth_verify_client(sd_bus *b) {
char *e, *f, *start;
sd_id128_t peer;
unsigned i;
int r;
assert(b);
/* We expect two response lines: "OK" and possibly
* "AGREE_UNIX_FD" */
e = memmem_safe(b->rbuffer, b->rbuffer_size, "\r\n", 2);
if (!e)
return 0;
if (b->accept_fd) {
f = memmem(e + 2, b->rbuffer_size - (e - (char*) b->rbuffer) - 2, "\r\n", 2);
if (!f)
return 0;
start = f + 2;
} else {
f = NULL;
start = e + 2;
}
/* Nice! We got all the lines we need. First check the OK
* line */
if (e - (char*) b->rbuffer != 3 + 32)
return -EPERM;
if (memcmp(b->rbuffer, "OK ", 3))
return -EPERM;
b->auth = b->anonymous_auth ? BUS_AUTH_ANONYMOUS : BUS_AUTH_EXTERNAL;
for (i = 0; i < 32; i += 2) {
int x, y;
x = unhexchar(((char*) b->rbuffer)[3 + i]);
y = unhexchar(((char*) b->rbuffer)[3 + i + 1]);
if (x < 0 || y < 0)
return -EINVAL;
peer.bytes[i/2] = ((uint8_t) x << 4 | (uint8_t) y);
}
if (!sd_id128_is_null(b->server_id) &&
!sd_id128_equal(b->server_id, peer))
return -EPERM;
b->server_id = peer;
/* And possibly check the second line, too */
if (f)
b->can_fds =
(f - e == STRLEN("\r\nAGREE_UNIX_FD")) &&
memcmp(e + 2, "AGREE_UNIX_FD",
STRLEN("AGREE_UNIX_FD")) == 0;
b->rbuffer_size -= (start - (char*) b->rbuffer);
memmove(b->rbuffer, start, b->rbuffer_size);
r = bus_start_running(b);
if (r < 0)
return r;
return 1;
}
static bool line_equals(const char *s, size_t m, const char *line) {
size_t l;
l = strlen(line);
if (l != m)
return false;
return memcmp(s, line, l) == 0;
}
static bool line_begins(const char *s, size_t m, const char *word) {
const char *p;
p = memory_startswith(s, m, word);
if (!p)
return false;
return IN_SET(*p, 0, ' ');
}
static int verify_anonymous_token(sd_bus *b, const char *p, size_t l) {
_cleanup_free_ char *token = NULL;
size_t len;
int r;
if (!b->anonymous_auth)
return 0;
if (l <= 0)
return 1;
assert(p[0] == ' ');
p++; l--;
if (l % 2 != 0)
return 0;
r = unhexmem(p, l, (void **) &token, &len);
if (r < 0)
return 0;
if (memchr(token, 0, len))
return 0;
return !!utf8_is_valid(token);
}
static int verify_external_token(sd_bus *b, const char *p, size_t l) {
_cleanup_free_ char *token = NULL;
size_t len;
uid_t u;
int r;
/* We don't do any real authentication here. Instead, we if
* the owner of this bus wanted authentication he should have
* checked SO_PEERCRED before even creating the bus object. */
if (!b->anonymous_auth && !b->ucred_valid)
return 0;
if (l <= 0)
return 1;
assert(p[0] == ' ');
p++; l--;
if (l % 2 != 0)
return 0;
r = unhexmem(p, l, (void**) &token, &len);
if (r < 0)
return 0;
if (memchr(token, 0, len))
return 0;
r = parse_uid(token, &u);
if (r < 0)
return 0;
/* We ignore the passed value if anonymous authentication is
* on anyway. */
if (!b->anonymous_auth && u != b->ucred.uid)
return 0;
return 1;
}
static int bus_socket_auth_write(sd_bus *b, const char *t) {
char *p;
size_t l;
assert(b);
assert(t);
/* We only make use of the first iovec */
assert(IN_SET(b->auth_index, 0, 1));
l = strlen(t);
p = malloc(b->auth_iovec[0].iov_len + l);
if (!p)
return -ENOMEM;
memcpy_safe(p, b->auth_iovec[0].iov_base, b->auth_iovec[0].iov_len);
memcpy(p + b->auth_iovec[0].iov_len, t, l);
b->auth_iovec[0].iov_base = p;
b->auth_iovec[0].iov_len += l;
free(b->auth_buffer);
b->auth_buffer = p;
b->auth_index = 0;
return 0;
}
static int bus_socket_auth_write_ok(sd_bus *b) {
char t[3 + 32 + 2 + 1];
assert(b);
xsprintf(t, "OK " SD_ID128_FORMAT_STR "\r\n", SD_ID128_FORMAT_VAL(b->server_id));
return bus_socket_auth_write(b, t);
}
static int bus_socket_auth_verify_server(sd_bus *b) {
char *e;
const char *line;
size_t l;
bool processed = false;
int r;
assert(b);
if (b->rbuffer_size < 1)
return 0;
/* First char must be a NUL byte */
if (*(char*) b->rbuffer != 0)
return -EIO;
if (b->rbuffer_size < 3)
return 0;
/* Begin with the first line */
if (b->auth_rbegin <= 0)
b->auth_rbegin = 1;
for (;;) {
/* Check if line is complete */
line = (char*) b->rbuffer + b->auth_rbegin;
e = memmem(line, b->rbuffer_size - b->auth_rbegin, "\r\n", 2);
if (!e)
return processed;
l = e - line;
if (line_begins(line, l, "AUTH ANONYMOUS")) {
r = verify_anonymous_token(b, line + 14, l - 14);
if (r < 0)
return r;
if (r == 0)
r = bus_socket_auth_write(b, "REJECTED\r\n");
else {
b->auth = BUS_AUTH_ANONYMOUS;
r = bus_socket_auth_write_ok(b);
}
} else if (line_begins(line, l, "AUTH EXTERNAL")) {
r = verify_external_token(b, line + 13, l - 13);
if (r < 0)
return r;
if (r == 0)
r = bus_socket_auth_write(b, "REJECTED\r\n");
else {
b->auth = BUS_AUTH_EXTERNAL;
r = bus_socket_auth_write_ok(b);
}
} else if (line_begins(line, l, "AUTH"))
r = bus_socket_auth_write(b, "REJECTED EXTERNAL ANONYMOUS\r\n");
else if (line_equals(line, l, "CANCEL") ||
line_begins(line, l, "ERROR")) {
b->auth = _BUS_AUTH_INVALID;
r = bus_socket_auth_write(b, "REJECTED\r\n");
} else if (line_equals(line, l, "BEGIN")) {
if (b->auth == _BUS_AUTH_INVALID)
r = bus_socket_auth_write(b, "ERROR\r\n");
else {
/* We can't leave from the auth phase
* before we haven't written
* everything queued, so let's check
* that */
if (bus_socket_auth_needs_write(b))
return 1;
b->rbuffer_size -= (e + 2 - (char*) b->rbuffer);
memmove(b->rbuffer, e + 2, b->rbuffer_size);
return bus_start_running(b);
}
} else if (line_begins(line, l, "DATA")) {
if (b->auth == _BUS_AUTH_INVALID)
r = bus_socket_auth_write(b, "ERROR\r\n");
else {
if (b->auth == BUS_AUTH_ANONYMOUS)
r = verify_anonymous_token(b, line + 4, l - 4);
else
r = verify_external_token(b, line + 4, l - 4);
if (r < 0)
return r;
if (r == 0) {
b->auth = _BUS_AUTH_INVALID;
r = bus_socket_auth_write(b, "REJECTED\r\n");
} else
r = bus_socket_auth_write_ok(b);
}
} else if (line_equals(line, l, "NEGOTIATE_UNIX_FD")) {
if (b->auth == _BUS_AUTH_INVALID || !b->accept_fd)
r = bus_socket_auth_write(b, "ERROR\r\n");
else {
b->can_fds = true;
r = bus_socket_auth_write(b, "AGREE_UNIX_FD\r\n");
}
} else
r = bus_socket_auth_write(b, "ERROR\r\n");
if (r < 0)
return r;
b->auth_rbegin = e + 2 - (char*) b->rbuffer;
processed = true;
}
}
static int bus_socket_auth_verify(sd_bus *b) {
assert(b);
if (b->is_server)
return bus_socket_auth_verify_server(b);
else
return bus_socket_auth_verify_client(b);
}
static int bus_socket_read_auth(sd_bus *b) {
struct msghdr mh;
struct iovec iov = {};
size_t n;
ssize_t k;
int r;
void *p;
union {
struct cmsghdr cmsghdr;
uint8_t buf[CMSG_SPACE(sizeof(int) * BUS_FDS_MAX)];
} control;
bool handle_cmsg = false;
assert(b);
assert(b->state == BUS_AUTHENTICATING);
r = bus_socket_auth_verify(b);
if (r != 0)
return r;
n = MAX(256u, b->rbuffer_size * 2);
if (n > BUS_AUTH_SIZE_MAX)
n = BUS_AUTH_SIZE_MAX;
if (b->rbuffer_size >= n)
return -ENOBUFS;
p = realloc(b->rbuffer, n);
if (!p)
return -ENOMEM;
b->rbuffer = p;
iov.iov_base = (uint8_t*) b->rbuffer + b->rbuffer_size;
iov.iov_len = n - b->rbuffer_size;
if (b->prefer_readv)
k = readv(b->input_fd, &iov, 1);
else {
zero(mh);
mh.msg_iov = &iov;
mh.msg_iovlen = 1;
mh.msg_control = &control;
mh.msg_controllen = sizeof(control);
k = recvmsg(b->input_fd, &mh, MSG_DONTWAIT|MSG_CMSG_CLOEXEC);
if (k < 0 && errno == ENOTSOCK) {
b->prefer_readv = true;
k = readv(b->input_fd, &iov, 1);
} else
handle_cmsg = true;
}
if (k < 0)
return errno == EAGAIN ? 0 : -errno;
if (k == 0)
return -ECONNRESET;
b->rbuffer_size += k;
if (handle_cmsg) {
struct cmsghdr *cmsg;
CMSG_FOREACH(cmsg, &mh)
if (cmsg->cmsg_level == SOL_SOCKET &&
cmsg->cmsg_type == SCM_RIGHTS) {
int j;
/* Whut? We received fds during the auth
* protocol? Somebody is playing games with
* us. Close them all, and fail */
j = (cmsg->cmsg_len - CMSG_LEN(0)) / sizeof(int);
close_many((int*) CMSG_DATA(cmsg), j);
return -EIO;
} else
log_debug("Got unexpected auxiliary data with level=%d and type=%d",
cmsg->cmsg_level, cmsg->cmsg_type);
}
r = bus_socket_auth_verify(b);
if (r != 0)
return r;
return 1;
}
void bus_socket_setup(sd_bus *b) {
assert(b);
/* Increase the buffers to 8 MB */
(void) fd_inc_rcvbuf(b->input_fd, SNDBUF_SIZE);
(void) fd_inc_sndbuf(b->output_fd, SNDBUF_SIZE);
b->message_version = 1;
b->message_endian = 0;
}
static void bus_get_peercred(sd_bus *b) {
int r;
assert(b);
assert(!b->ucred_valid);
assert(!b->label);
assert(b->n_groups == (size_t) -1);
/* Get the peer for socketpair() sockets */
b->ucred_valid = getpeercred(b->input_fd, &b->ucred) >= 0;
/* Get the SELinux context of the peer */
r = getpeersec(b->input_fd, &b->label);
if (r < 0 && !IN_SET(r, -EOPNOTSUPP, -ENOPROTOOPT))
log_debug_errno(r, "Failed to determine peer security context: %m");
/* Get the list of auxiliary groups of the peer */
r = getpeergroups(b->input_fd, &b->groups);
if (r >= 0)
b->n_groups = (size_t) r;
else if (!IN_SET(r, -EOPNOTSUPP, -ENOPROTOOPT))
log_debug_errno(r, "Failed to determine peer's group list: %m");
}
static int bus_socket_start_auth_client(sd_bus *b) {
size_t l;
const char *auth_suffix, *auth_prefix;
assert(b);
if (b->anonymous_auth) {
auth_prefix = "\0AUTH ANONYMOUS ";
/* For ANONYMOUS auth we send some arbitrary "trace" string */
l = 9;
b->auth_buffer = hexmem("anonymous", l);
} else {
char text[DECIMAL_STR_MAX(uid_t) + 1];
auth_prefix = "\0AUTH EXTERNAL ";
xsprintf(text, UID_FMT, geteuid());
l = strlen(text);
b->auth_buffer = hexmem(text, l);
}
if (!b->auth_buffer)
return -ENOMEM;
if (b->accept_fd)
auth_suffix = "\r\nNEGOTIATE_UNIX_FD\r\nBEGIN\r\n";
else
auth_suffix = "\r\nBEGIN\r\n";
b->auth_iovec[0].iov_base = (void*) auth_prefix;
b->auth_iovec[0].iov_len = 1 + strlen(auth_prefix + 1);
b->auth_iovec[1].iov_base = (void*) b->auth_buffer;
b->auth_iovec[1].iov_len = l * 2;
b->auth_iovec[2].iov_base = (void*) auth_suffix;
b->auth_iovec[2].iov_len = strlen(auth_suffix);
return bus_socket_write_auth(b);
}
int bus_socket_start_auth(sd_bus *b) {
assert(b);
bus_get_peercred(b);
bus_set_state(b, BUS_AUTHENTICATING);
b->auth_timeout = now(CLOCK_MONOTONIC) + BUS_AUTH_TIMEOUT;
if (sd_is_socket(b->input_fd, AF_UNIX, 0, 0) <= 0)
b->accept_fd = false;
if (b->output_fd != b->input_fd)
if (sd_is_socket(b->output_fd, AF_UNIX, 0, 0) <= 0)
b->accept_fd = false;
if (b->is_server)
return bus_socket_read_auth(b);
else
return bus_socket_start_auth_client(b);
}
static int bus_socket_inotify_setup(sd_bus *b) {
_cleanup_free_ int *new_watches = NULL;
_cleanup_free_ char *absolute = NULL;
size_t n_allocated = 0, n = 0, done = 0, i;
unsigned max_follow = 32;
const char *p;
int wd, r;
assert(b);
assert(b->watch_bind);
assert(b->sockaddr.sa.sa_family == AF_UNIX);
assert(b->sockaddr.un.sun_path[0] != 0);
/* Sets up an inotify fd in case watch_bind is enabled: wait until the configured AF_UNIX file system socket
* appears before connecting to it. The implemented is pretty simplistic: we just subscribe to relevant changes
* to all prefix components of the path, and every time we get an event for that we try to reconnect again,
* without actually caring what precisely the event we got told us. If we still can't connect we re-subscribe
* to all relevant changes of anything in the path, so that our watches include any possibly newly created path
* components. */
if (b->inotify_fd < 0) {
b->inotify_fd = inotify_init1(IN_NONBLOCK|IN_CLOEXEC);
if (b->inotify_fd < 0)
return -errno;
b->inotify_fd = fd_move_above_stdio(b->inotify_fd);
}
/* Make sure the path is NUL terminated */
p = strndupa(b->sockaddr.un.sun_path, sizeof(b->sockaddr.un.sun_path));
/* Make sure the path is absolute */
r = path_make_absolute_cwd(p, &absolute);
if (r < 0)
goto fail;
/* Watch all parent directories, and don't mind any prefix that doesn't exist yet. For the innermost directory
* that exists we want to know when files are created or moved into it. For all parents of it we just care if
* they are removed or renamed. */
if (!GREEDY_REALLOC(new_watches, n_allocated, n + 1)) {
r = -ENOMEM;
goto fail;
}
/* Start with the top-level directory, which is a bit simpler than the rest, since it can't be a symlink, and
* always exists */
wd = inotify_add_watch(b->inotify_fd, "/", IN_CREATE|IN_MOVED_TO);
if (wd < 0) {
r = log_debug_errno(errno, "Failed to add inotify watch on /: %m");
goto fail;
} else
new_watches[n++] = wd;
for (;;) {
_cleanup_free_ char *component = NULL, *prefix = NULL, *destination = NULL;
size_t n_slashes, n_component;
char *c = NULL;
n_slashes = strspn(absolute + done, "/");
n_component = n_slashes + strcspn(absolute + done + n_slashes, "/");
if (n_component == 0) /* The end */
break;
component = strndup(absolute + done, n_component);
if (!component) {
r = -ENOMEM;
goto fail;
}
/* A trailing slash? That's a directory, and not a socket then */
if (path_equal(component, "/")) {
r = -EISDIR;
goto fail;
}
/* A single dot? Let's eat this up */
if (path_equal(component, "/.")) {
done += n_component;
continue;
}
prefix = strndup(absolute, done + n_component);
if (!prefix) {
r = -ENOMEM;
goto fail;
}
if (!GREEDY_REALLOC(new_watches, n_allocated, n + 1)) {
r = -ENOMEM;
goto fail;
}
wd = inotify_add_watch(b->inotify_fd, prefix, IN_DELETE_SELF|IN_MOVE_SELF|IN_ATTRIB|IN_CREATE|IN_MOVED_TO|IN_DONT_FOLLOW);
log_debug("Added inotify watch for %s on bus %s: %i", prefix, strna(b->description), wd);
if (wd < 0) {
if (IN_SET(errno, ENOENT, ELOOP))
break; /* This component doesn't exist yet, or the path contains a cyclic symlink right now */
r = log_debug_errno(errno, "Failed to add inotify watch on %s: %m", empty_to_root(prefix));
goto fail;
} else
new_watches[n++] = wd;
/* Check if this is possibly a symlink. If so, let's follow it and watch it too. */
r = readlink_malloc(prefix, &destination);
if (r == -EINVAL) { /* not a symlink */
done += n_component;
continue;
}
if (r < 0)
goto fail;
if (isempty(destination)) { /* Empty symlink target? Yuck! */
r = -EINVAL;
goto fail;
}
if (max_follow <= 0) { /* Let's make sure we don't follow symlinks forever */
r = -ELOOP;
goto fail;
}
if (path_is_absolute(destination)) {
/* For absolute symlinks we build the new path and start anew */
c = strjoin(destination, absolute + done + n_component);
done = 0;
} else {
_cleanup_free_ char *t = NULL;
/* For relative symlinks we replace the last component, and try again */
t = strndup(absolute, done);
if (!t)
return -ENOMEM;
c = strjoin(t, "/", destination, absolute + done + n_component);
}
if (!c) {
r = -ENOMEM;
goto fail;
}
free(absolute);
absolute = c;
max_follow--;
}
/* And now, let's remove all watches from the previous iteration we don't need anymore */
for (i = 0; i < b->n_inotify_watches; i++) {
bool found = false;
size_t j;
for (j = 0; j < n; j++)
if (new_watches[j] == b->inotify_watches[i]) {
found = true;
break;
}
if (found)
continue;
(void) inotify_rm_watch(b->inotify_fd, b->inotify_watches[i]);
}
free_and_replace(b->inotify_watches, new_watches);
b->n_inotify_watches = n;
return 0;
fail:
bus_close_inotify_fd(b);
return r;
}
int bus_socket_connect(sd_bus *b) {
bool inotify_done = false;
int r;
assert(b);
for (;;) {
assert(b->input_fd < 0);
assert(b->output_fd < 0);
assert(b->sockaddr.sa.sa_family != AF_UNSPEC);
b->input_fd = socket(b->sockaddr.sa.sa_family, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
if (b->input_fd < 0)
return -errno;
b->input_fd = fd_move_above_stdio(b->input_fd);
b->output_fd = b->input_fd;
bus_socket_setup(b);
if (connect(b->input_fd, &b->sockaddr.sa, b->sockaddr_size) < 0) {
if (errno == EINPROGRESS) {
/* If we have any inotify watches open, close them now, we don't need them anymore, as
* we have successfully initiated a connection */
bus_close_inotify_fd(b);
/* Note that very likely we are already in BUS_OPENING state here, as we enter it when
* we start parsing the address string. The only reason we set the state explicitly
* here, is to undo BUS_WATCH_BIND, in case we did the inotify magic. */
bus_set_state(b, BUS_OPENING);
return 1;
}
if (IN_SET(errno, ENOENT, ECONNREFUSED) && /* ENOENT → unix socket doesn't exist at all; ECONNREFUSED → unix socket stale */
b->watch_bind &&
b->sockaddr.sa.sa_family == AF_UNIX &&
b->sockaddr.un.sun_path[0] != 0) {
/* This connection attempt failed, let's release the socket for now, and start with a
* fresh one when reconnecting. */
bus_close_io_fds(b);
if (inotify_done) {
/* inotify set up already, don't do it again, just return now, and remember
* that we are waiting for inotify events now. */
bus_set_state(b, BUS_WATCH_BIND);
return 1;
}
/* This is a file system socket, and the inotify logic is enabled. Let's create the necessary inotify fd. */
r = bus_socket_inotify_setup(b);
if (r < 0)
return r;
/* Let's now try to connect a second time, because in theory there's otherwise a race
* here: the socket might have been created in the time between our first connect() and
* the time we set up the inotify logic. But let's remember that we set up inotify now,
* so that we don't do the connect() more than twice. */
inotify_done = true;
} else
return -errno;
} else
break;
}
/* Yay, established, we don't need no inotify anymore! */
bus_close_inotify_fd(b);
return bus_socket_start_auth(b);
}
int bus_socket_exec(sd_bus *b) {
int s[2], r;
assert(b);
assert(b->input_fd < 0);
assert(b->output_fd < 0);
assert(b->exec_path);
assert(b->busexec_pid == 0);
r = socketpair(AF_UNIX, SOCK_STREAM|SOCK_NONBLOCK|SOCK_CLOEXEC, 0, s);
if (r < 0)
return -errno;
r = safe_fork_full("(sd-busexec)", s+1, 1, FORK_RESET_SIGNALS|FORK_CLOSE_ALL_FDS, &b->busexec_pid);
if (r < 0) {
safe_close_pair(s);
return r;
}
if (r == 0) {
/* Child */
if (rearrange_stdio(s[1], s[1], STDERR_FILENO) < 0)
_exit(EXIT_FAILURE);
if (b->exec_argv)
execvp(b->exec_path, b->exec_argv);
else {
const char *argv[] = { b->exec_path, NULL };
execvp(b->exec_path, (char**) argv);
}
_exit(EXIT_FAILURE);
}
safe_close(s[1]);
b->output_fd = b->input_fd = fd_move_above_stdio(s[0]);
bus_socket_setup(b);
return bus_socket_start_auth(b);
}
int bus_socket_take_fd(sd_bus *b) {
assert(b);
bus_socket_setup(b);
return bus_socket_start_auth(b);
}
int bus_socket_write_message(sd_bus *bus, sd_bus_message *m, size_t *idx) {
struct iovec *iov;
ssize_t k;
size_t n;
unsigned j;
int r;
assert(bus);
assert(m);
assert(idx);
assert(IN_SET(bus->state, BUS_RUNNING, BUS_HELLO));
if (*idx >= BUS_MESSAGE_SIZE(m))
return 0;
r = bus_message_setup_iovec(m);
if (r < 0)
return r;
n = m->n_iovec * sizeof(struct iovec);
iov = alloca(n);
memcpy_safe(iov, m->iovec, n);
j = 0;
iovec_advance(iov, &j, *idx);
if (bus->prefer_writev)
k = writev(bus->output_fd, iov, m->n_iovec);
else {
struct msghdr mh = {
.msg_iov = iov,
.msg_iovlen = m->n_iovec,
};
if (m->n_fds > 0 && *idx == 0) {
struct cmsghdr *control;
mh.msg_control = control = alloca(CMSG_SPACE(sizeof(int) * m->n_fds));
mh.msg_controllen = control->cmsg_len = CMSG_LEN(sizeof(int) * m->n_fds);
control->cmsg_level = SOL_SOCKET;
control->cmsg_type = SCM_RIGHTS;
memcpy(CMSG_DATA(control), m->fds, sizeof(int) * m->n_fds);
}
k = sendmsg(bus->output_fd, &mh, MSG_DONTWAIT|MSG_NOSIGNAL);
if (k < 0 && errno == ENOTSOCK) {
bus->prefer_writev = true;
k = writev(bus->output_fd, iov, m->n_iovec);
}
}
if (k < 0)
return errno == EAGAIN ? 0 : -errno;
*idx += (size_t) k;
return 1;
}
static int bus_socket_read_message_need(sd_bus *bus, size_t *need) {
uint32_t a, b;
uint8_t e;
uint64_t sum;
assert(bus);
assert(need);
assert(IN_SET(bus->state, BUS_RUNNING, BUS_HELLO));
if (bus->rbuffer_size < sizeof(struct bus_header)) {
*need = sizeof(struct bus_header) + 8;
/* Minimum message size:
*
* Header +
*
* Method Call: +2 string headers
* Signal: +3 string headers
* Method Error: +1 string headers
* +1 uint32 headers
* Method Reply: +1 uint32 headers
*
* A string header is at least 9 bytes
* A uint32 header is at least 8 bytes
*
* Hence the minimum message size of a valid message
* is header + 8 bytes */
return 0;
}
a = ((const uint32_t*) bus->rbuffer)[1];
b = ((const uint32_t*) bus->rbuffer)[3];
e = ((const uint8_t*) bus->rbuffer)[0];
if (e == BUS_LITTLE_ENDIAN) {
a = le32toh(a);
b = le32toh(b);
} else if (e == BUS_BIG_ENDIAN) {
a = be32toh(a);
b = be32toh(b);
} else
return -EBADMSG;
sum = (uint64_t) sizeof(struct bus_header) + (uint64_t) ALIGN_TO(b, 8) + (uint64_t) a;
if (sum >= BUS_MESSAGE_SIZE_MAX)
return -ENOBUFS;
*need = (size_t) sum;
return 0;
}
static int bus_socket_make_message(sd_bus *bus, size_t size) {
sd_bus_message *t;
void *b;
int r;
assert(bus);
assert(bus->rbuffer_size >= size);
assert(IN_SET(bus->state, BUS_RUNNING, BUS_HELLO));
r = bus_rqueue_make_room(bus);
if (r < 0)
return r;
if (bus->rbuffer_size > size) {
b = memdup((const uint8_t*) bus->rbuffer + size,
bus->rbuffer_size - size);
if (!b)
return -ENOMEM;
} else
b = NULL;
r = bus_message_from_malloc(bus,
bus->rbuffer, size,
bus->fds, bus->n_fds,
NULL,
&t);
if (r < 0) {
free(b);
return r;
}
bus->rbuffer = b;
bus->rbuffer_size -= size;
bus->fds = NULL;
bus->n_fds = 0;
bus->rqueue[bus->rqueue_size++] = t;
return 1;
}
int bus_socket_read_message(sd_bus *bus) {
struct msghdr mh;
struct iovec iov = {};
ssize_t k;
size_t need;
int r;
void *b;
union {
struct cmsghdr cmsghdr;
uint8_t buf[CMSG_SPACE(sizeof(int) * BUS_FDS_MAX)];
} control;
bool handle_cmsg = false;
assert(bus);
assert(IN_SET(bus->state, BUS_RUNNING, BUS_HELLO));
r = bus_socket_read_message_need(bus, &need);
if (r < 0)
return r;
if (bus->rbuffer_size >= need)
return bus_socket_make_message(bus, need);
b = realloc(bus->rbuffer, need);
if (!b)
return -ENOMEM;
bus->rbuffer = b;
iov.iov_base = (uint8_t*) bus->rbuffer + bus->rbuffer_size;
iov.iov_len = need - bus->rbuffer_size;
if (bus->prefer_readv)
k = readv(bus->input_fd, &iov, 1);
else {
zero(mh);
mh.msg_iov = &iov;
mh.msg_iovlen = 1;
mh.msg_control = &control;
mh.msg_controllen = sizeof(control);
k = recvmsg(bus->input_fd, &mh, MSG_DONTWAIT|MSG_CMSG_CLOEXEC);
if (k < 0 && errno == ENOTSOCK) {
bus->prefer_readv = true;
k = readv(bus->input_fd, &iov, 1);
} else
handle_cmsg = true;
}
if (k < 0)
return errno == EAGAIN ? 0 : -errno;
if (k == 0)
return -ECONNRESET;
bus->rbuffer_size += k;
if (handle_cmsg) {
struct cmsghdr *cmsg;
CMSG_FOREACH(cmsg, &mh)
if (cmsg->cmsg_level == SOL_SOCKET &&
cmsg->cmsg_type == SCM_RIGHTS) {
int n, *f, i;
n = (cmsg->cmsg_len - CMSG_LEN(0)) / sizeof(int);
if (!bus->can_fds) {
/* Whut? We received fds but this
* isn't actually enabled? Close them,
* and fail */
close_many((int*) CMSG_DATA(cmsg), n);
return -EIO;
}
f = reallocarray(bus->fds, bus->n_fds + n, sizeof(int));
if (!f) {
close_many((int*) CMSG_DATA(cmsg), n);
return -ENOMEM;
}
for (i = 0; i < n; i++)
f[bus->n_fds++] = fd_move_above_stdio(((int*) CMSG_DATA(cmsg))[i]);
bus->fds = f;
} else
log_debug("Got unexpected auxiliary data with level=%d and type=%d",
cmsg->cmsg_level, cmsg->cmsg_type);
}
r = bus_socket_read_message_need(bus, &need);
if (r < 0)
return r;
if (bus->rbuffer_size >= need)
return bus_socket_make_message(bus, need);
return 1;
}
int bus_socket_process_opening(sd_bus *b) {
int error = 0;
socklen_t slen = sizeof(error);
struct pollfd p = {
.fd = b->output_fd,
.events = POLLOUT,
};
int r;
assert(b->state == BUS_OPENING);
r = poll(&p, 1, 0);
if (r < 0)
return -errno;
if (!(p.revents & (POLLOUT|POLLERR|POLLHUP)))
return 0;
r = getsockopt(b->output_fd, SOL_SOCKET, SO_ERROR, &error, &slen);
if (r < 0)
b->last_connect_error = errno;
else if (error != 0)
b->last_connect_error = error;
else if (p.revents & (POLLERR|POLLHUP))
b->last_connect_error = ECONNREFUSED;
else
return bus_socket_start_auth(b);
return bus_next_address(b);
}
int bus_socket_process_authenticating(sd_bus *b) {
int r;
assert(b);
assert(b->state == BUS_AUTHENTICATING);
if (now(CLOCK_MONOTONIC) >= b->auth_timeout)
return -ETIMEDOUT;
r = bus_socket_write_auth(b);
if (r != 0)
return r;
return bus_socket_read_auth(b);
}
int bus_socket_process_watch_bind(sd_bus *b) {
int r, q;
assert(b);
assert(b->state == BUS_WATCH_BIND);
assert(b->inotify_fd >= 0);
r = flush_fd(b->inotify_fd);
if (r <= 0)
return r;
log_debug("Got inotify event on bus %s.", strna(b->description));
/* We flushed events out of the inotify fd. In that case, maybe the socket is valid now? Let's try to connect
* to it again */
r = bus_socket_connect(b);
if (r < 0)
return r;
q = bus_attach_io_events(b);
if (q < 0)
return q;
q = bus_attach_inotify_event(b);
if (q < 0)
return q;
return r;
}