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|
/* SPDX-License-Identifier: LGPL-2.1+
*
* libudev - interface to udev device information
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*/
#include <errno.h>
#include <poll.h>
#include <stddef.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <unistd.h>
#include "alloc-util.h"
#include "fd-util.h"
#include "format-util.h"
#include "socket-util.h"
#include "strxcpyx.h"
#include "udev-ctrl.h"
/* wire protocol magic must match */
#define UDEV_CTRL_MAGIC 0xdead1dea
enum udev_ctrl_msg_type {
UDEV_CTRL_UNKNOWN,
UDEV_CTRL_SET_LOG_LEVEL,
UDEV_CTRL_STOP_EXEC_QUEUE,
UDEV_CTRL_START_EXEC_QUEUE,
UDEV_CTRL_RELOAD,
UDEV_CTRL_SET_ENV,
UDEV_CTRL_SET_CHILDREN_MAX,
UDEV_CTRL_PING,
UDEV_CTRL_EXIT,
};
struct udev_ctrl_msg_wire {
char version[16];
unsigned magic;
enum udev_ctrl_msg_type type;
union {
int intval;
char buf[256];
};
};
struct udev_ctrl_msg {
unsigned n_ref;
struct udev_ctrl_connection *conn;
struct udev_ctrl_msg_wire ctrl_msg_wire;
};
struct udev_ctrl {
unsigned n_ref;
int sock;
union sockaddr_union saddr;
socklen_t addrlen;
bool bound;
bool cleanup_socket;
bool connected;
};
struct udev_ctrl_connection {
unsigned n_ref;
struct udev_ctrl *uctrl;
int sock;
};
struct udev_ctrl *udev_ctrl_new_from_fd(int fd) {
struct udev_ctrl *uctrl;
int r;
uctrl = new0(struct udev_ctrl, 1);
if (uctrl == NULL)
return NULL;
uctrl->n_ref = 1;
if (fd < 0) {
uctrl->sock = socket(AF_LOCAL, SOCK_SEQPACKET|SOCK_NONBLOCK|SOCK_CLOEXEC, 0);
if (uctrl->sock < 0) {
log_error_errno(errno, "error getting socket: %m");
udev_ctrl_unref(uctrl);
return NULL;
}
} else {
uctrl->bound = true;
uctrl->sock = fd;
}
/*
* FIXME: remove it as soon as we can depend on this:
* http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=90c6bd34f884cd9cee21f1d152baf6c18bcac949
*/
r = setsockopt_int(uctrl->sock, SOL_SOCKET, SO_PASSCRED, true);
if (r < 0)
log_warning_errno(r, "could not set SO_PASSCRED: %m");
uctrl->saddr.un = (struct sockaddr_un) {
.sun_family = AF_UNIX,
.sun_path = "/run/udev/control",
};
uctrl->addrlen = SOCKADDR_UN_LEN(uctrl->saddr.un);
return uctrl;
}
struct udev_ctrl *udev_ctrl_new(void) {
return udev_ctrl_new_from_fd(-1);
}
int udev_ctrl_enable_receiving(struct udev_ctrl *uctrl) {
int err;
if (!uctrl->bound) {
err = bind(uctrl->sock, &uctrl->saddr.sa, uctrl->addrlen);
if (err < 0 && errno == EADDRINUSE) {
(void) sockaddr_un_unlink(&uctrl->saddr.un);
err = bind(uctrl->sock, &uctrl->saddr.sa, uctrl->addrlen);
}
if (err < 0)
return log_error_errno(errno, "bind failed: %m");
err = listen(uctrl->sock, 0);
if (err < 0)
return log_error_errno(errno, "listen failed: %m");
uctrl->bound = true;
uctrl->cleanup_socket = true;
}
return 0;
}
static struct udev_ctrl *udev_ctrl_free(struct udev_ctrl *uctrl) {
assert(uctrl);
safe_close(uctrl->sock);
return mfree(uctrl);
}
DEFINE_PRIVATE_TRIVIAL_REF_FUNC(struct udev_ctrl, udev_ctrl);
DEFINE_TRIVIAL_UNREF_FUNC(struct udev_ctrl, udev_ctrl, udev_ctrl_free);
int udev_ctrl_cleanup(struct udev_ctrl *uctrl) {
if (uctrl == NULL)
return 0;
if (uctrl->cleanup_socket)
sockaddr_un_unlink(&uctrl->saddr.un);
return 0;
}
int udev_ctrl_get_fd(struct udev_ctrl *uctrl) {
if (uctrl == NULL)
return -EINVAL;
return uctrl->sock;
}
struct udev_ctrl_connection *udev_ctrl_get_connection(struct udev_ctrl *uctrl) {
struct udev_ctrl_connection *conn;
struct ucred ucred = {};
int r;
conn = new(struct udev_ctrl_connection, 1);
if (conn == NULL)
return NULL;
conn->n_ref = 1;
conn->uctrl = uctrl;
conn->sock = accept4(uctrl->sock, NULL, NULL, SOCK_CLOEXEC|SOCK_NONBLOCK);
if (conn->sock < 0) {
if (errno != EINTR)
log_error_errno(errno, "unable to receive ctrl connection: %m");
goto err;
}
/* check peer credential of connection */
r = getpeercred(conn->sock, &ucred);
if (r < 0) {
log_error_errno(r, "unable to receive credentials of ctrl connection: %m");
goto err;
}
if (ucred.uid > 0) {
log_error("sender uid="UID_FMT", message ignored", ucred.uid);
goto err;
}
/* enable receiving of the sender credentials in the messages */
r = setsockopt_int(conn->sock, SOL_SOCKET, SO_PASSCRED, true);
if (r < 0)
log_warning_errno(r, "could not set SO_PASSCRED: %m");
udev_ctrl_ref(uctrl);
return conn;
err:
safe_close(conn->sock);
return mfree(conn);
}
static struct udev_ctrl_connection *udev_ctrl_connection_free(struct udev_ctrl_connection *conn) {
assert(conn);
safe_close(conn->sock);
udev_ctrl_unref(conn->uctrl);
return mfree(conn);
}
DEFINE_TRIVIAL_REF_UNREF_FUNC(struct udev_ctrl_connection, udev_ctrl_connection, udev_ctrl_connection_free);
static int ctrl_send(struct udev_ctrl *uctrl, enum udev_ctrl_msg_type type, int intval, const char *buf, int timeout) {
struct udev_ctrl_msg_wire ctrl_msg_wire;
int err = 0;
memzero(&ctrl_msg_wire, sizeof(struct udev_ctrl_msg_wire));
strcpy(ctrl_msg_wire.version, "udev-" PACKAGE_VERSION);
ctrl_msg_wire.magic = UDEV_CTRL_MAGIC;
ctrl_msg_wire.type = type;
if (buf != NULL)
strscpy(ctrl_msg_wire.buf, sizeof(ctrl_msg_wire.buf), buf);
else
ctrl_msg_wire.intval = intval;
if (!uctrl->connected) {
if (connect(uctrl->sock, &uctrl->saddr.sa, uctrl->addrlen) < 0) {
err = -errno;
goto out;
}
uctrl->connected = true;
}
if (send(uctrl->sock, &ctrl_msg_wire, sizeof(ctrl_msg_wire), 0) < 0) {
err = -errno;
goto out;
}
/* wait for peer message handling or disconnect */
for (;;) {
struct pollfd pfd[1];
int r;
pfd[0].fd = uctrl->sock;
pfd[0].events = POLLIN;
r = poll(pfd, 1, timeout * MSEC_PER_SEC);
if (r < 0) {
if (errno == EINTR)
continue;
err = -errno;
break;
}
if (r > 0 && pfd[0].revents & POLLERR) {
err = -EIO;
break;
}
if (r == 0)
err = -ETIMEDOUT;
break;
}
out:
return err;
}
int udev_ctrl_send_set_log_level(struct udev_ctrl *uctrl, int priority, int timeout) {
return ctrl_send(uctrl, UDEV_CTRL_SET_LOG_LEVEL, priority, NULL, timeout);
}
int udev_ctrl_send_stop_exec_queue(struct udev_ctrl *uctrl, int timeout) {
return ctrl_send(uctrl, UDEV_CTRL_STOP_EXEC_QUEUE, 0, NULL, timeout);
}
int udev_ctrl_send_start_exec_queue(struct udev_ctrl *uctrl, int timeout) {
return ctrl_send(uctrl, UDEV_CTRL_START_EXEC_QUEUE, 0, NULL, timeout);
}
int udev_ctrl_send_reload(struct udev_ctrl *uctrl, int timeout) {
return ctrl_send(uctrl, UDEV_CTRL_RELOAD, 0, NULL, timeout);
}
int udev_ctrl_send_set_env(struct udev_ctrl *uctrl, const char *key, int timeout) {
return ctrl_send(uctrl, UDEV_CTRL_SET_ENV, 0, key, timeout);
}
int udev_ctrl_send_set_children_max(struct udev_ctrl *uctrl, int count, int timeout) {
return ctrl_send(uctrl, UDEV_CTRL_SET_CHILDREN_MAX, count, NULL, timeout);
}
int udev_ctrl_send_ping(struct udev_ctrl *uctrl, int timeout) {
return ctrl_send(uctrl, UDEV_CTRL_PING, 0, NULL, timeout);
}
int udev_ctrl_send_exit(struct udev_ctrl *uctrl, int timeout) {
return ctrl_send(uctrl, UDEV_CTRL_EXIT, 0, NULL, timeout);
}
struct udev_ctrl_msg *udev_ctrl_receive_msg(struct udev_ctrl_connection *conn) {
struct udev_ctrl_msg *uctrl_msg;
ssize_t size;
struct cmsghdr *cmsg;
struct iovec iov;
char cred_msg[CMSG_SPACE(sizeof(struct ucred))];
struct msghdr smsg = {
.msg_iov = &iov,
.msg_iovlen = 1,
.msg_control = cred_msg,
.msg_controllen = sizeof(cred_msg),
};
struct ucred *cred;
uctrl_msg = new0(struct udev_ctrl_msg, 1);
if (uctrl_msg == NULL)
return NULL;
uctrl_msg->n_ref = 1;
uctrl_msg->conn = conn;
udev_ctrl_connection_ref(conn);
/* wait for the incoming message */
for (;;) {
struct pollfd pfd[1];
int r;
pfd[0].fd = conn->sock;
pfd[0].events = POLLIN;
r = poll(pfd, 1, 10000);
if (r < 0) {
if (errno == EINTR)
continue;
goto err;
} else if (r == 0) {
log_error("timeout waiting for ctrl message");
goto err;
} else {
if (!(pfd[0].revents & POLLIN)) {
log_error_errno(errno, "ctrl connection error: %m");
goto err;
}
}
break;
}
iov.iov_base = &uctrl_msg->ctrl_msg_wire;
iov.iov_len = sizeof(struct udev_ctrl_msg_wire);
size = recvmsg(conn->sock, &smsg, 0);
if (size < 0) {
log_error_errno(errno, "unable to receive ctrl message: %m");
goto err;
}
cmsg_close_all(&smsg);
cmsg = CMSG_FIRSTHDR(&smsg);
if (cmsg == NULL || cmsg->cmsg_type != SCM_CREDENTIALS) {
log_error("no sender credentials received, message ignored");
goto err;
}
cred = (struct ucred *) CMSG_DATA(cmsg);
if (cred->uid != 0) {
log_error("sender uid="UID_FMT", message ignored", cred->uid);
goto err;
}
if (uctrl_msg->ctrl_msg_wire.magic != UDEV_CTRL_MAGIC) {
log_error("message magic 0x%08x doesn't match, ignore it", uctrl_msg->ctrl_msg_wire.magic);
goto err;
}
return uctrl_msg;
err:
udev_ctrl_msg_unref(uctrl_msg);
return NULL;
}
static struct udev_ctrl_msg *udev_ctrl_msg_free(struct udev_ctrl_msg *ctrl_msg) {
assert(ctrl_msg);
udev_ctrl_connection_unref(ctrl_msg->conn);
return mfree(ctrl_msg);
}
DEFINE_TRIVIAL_UNREF_FUNC(struct udev_ctrl_msg, udev_ctrl_msg, udev_ctrl_msg_free);
int udev_ctrl_get_set_log_level(struct udev_ctrl_msg *ctrl_msg) {
if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_SET_LOG_LEVEL)
return ctrl_msg->ctrl_msg_wire.intval;
return -1;
}
int udev_ctrl_get_stop_exec_queue(struct udev_ctrl_msg *ctrl_msg) {
if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_STOP_EXEC_QUEUE)
return 1;
return -1;
}
int udev_ctrl_get_start_exec_queue(struct udev_ctrl_msg *ctrl_msg) {
if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_START_EXEC_QUEUE)
return 1;
return -1;
}
int udev_ctrl_get_reload(struct udev_ctrl_msg *ctrl_msg) {
if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_RELOAD)
return 1;
return -1;
}
const char *udev_ctrl_get_set_env(struct udev_ctrl_msg *ctrl_msg) {
if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_SET_ENV)
return ctrl_msg->ctrl_msg_wire.buf;
return NULL;
}
int udev_ctrl_get_set_children_max(struct udev_ctrl_msg *ctrl_msg) {
if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_SET_CHILDREN_MAX)
return ctrl_msg->ctrl_msg_wire.intval;
return -1;
}
int udev_ctrl_get_ping(struct udev_ctrl_msg *ctrl_msg) {
if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_PING)
return 1;
return -1;
}
int udev_ctrl_get_exit(struct udev_ctrl_msg *ctrl_msg) {
if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_EXIT)
return 1;
return -1;
}
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