| /* 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 "sd-event.h" |
| |
| #include "alloc-util.h" |
| #include "errno-util.h" |
| #include "fd-util.h" |
| #include "format-util.h" |
| #include "io-util.h" |
| #include "socket-util.h" |
| #include "strxcpyx.h" |
| #include "udev-ctrl.h" |
| #include "util.h" |
| |
| /* wire protocol magic must match */ |
| #define UDEV_CTRL_MAGIC 0xdead1dea |
| |
| struct udev_ctrl_msg_wire { |
| char version[16]; |
| unsigned magic; |
| enum udev_ctrl_msg_type type; |
| union udev_ctrl_msg_value value; |
| }; |
| |
| struct udev_ctrl { |
| unsigned n_ref; |
| int sock; |
| int sock_connect; |
| union sockaddr_union saddr; |
| socklen_t addrlen; |
| bool bound:1; |
| bool cleanup_socket:1; |
| bool connected:1; |
| bool maybe_disconnected:1; |
| sd_event *event; |
| sd_event_source *event_source; |
| sd_event_source *event_source_connect; |
| udev_ctrl_handler_t callback; |
| void *userdata; |
| }; |
| |
| int udev_ctrl_new_from_fd(struct udev_ctrl **ret, int fd) { |
| _cleanup_close_ int sock = -1; |
| struct udev_ctrl *uctrl; |
| int r; |
| |
| assert(ret); |
| |
| if (fd < 0) { |
| sock = socket(AF_LOCAL, SOCK_SEQPACKET|SOCK_NONBLOCK|SOCK_CLOEXEC, 0); |
| if (sock < 0) |
| return log_error_errno(errno, "Failed to create socket: %m"); |
| } |
| |
| uctrl = new(struct udev_ctrl, 1); |
| if (!uctrl) |
| return -ENOMEM; |
| |
| *uctrl = (struct udev_ctrl) { |
| .n_ref = 1, |
| .sock = fd >= 0 ? fd : TAKE_FD(sock), |
| .sock_connect = -1, |
| .bound = fd >= 0, |
| }; |
| |
| /* |
| * 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, "Failed to 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); |
| |
| *ret = TAKE_PTR(uctrl); |
| return 0; |
| } |
| |
| int udev_ctrl_enable_receiving(struct udev_ctrl *uctrl) { |
| int r; |
| |
| assert(uctrl); |
| |
| if (uctrl->bound) |
| return 0; |
| |
| r = bind(uctrl->sock, &uctrl->saddr.sa, uctrl->addrlen); |
| if (r < 0 && errno == EADDRINUSE) { |
| (void) sockaddr_un_unlink(&uctrl->saddr.un); |
| r = bind(uctrl->sock, &uctrl->saddr.sa, uctrl->addrlen); |
| } |
| |
| if (r < 0) |
| return log_error_errno(errno, "Failed to bind udev control socket: %m"); |
| |
| if (listen(uctrl->sock, 0) < 0) |
| return log_error_errno(errno, "Failed to listen udev control socket: %m"); |
| |
| uctrl->bound = true; |
| uctrl->cleanup_socket = true; |
| |
| return 0; |
| } |
| |
| static void udev_ctrl_disconnect(struct udev_ctrl *uctrl) { |
| if (!uctrl) |
| return; |
| |
| uctrl->event_source_connect = sd_event_source_unref(uctrl->event_source_connect); |
| uctrl->sock_connect = safe_close(uctrl->sock_connect); |
| } |
| |
| static struct udev_ctrl *udev_ctrl_free(struct udev_ctrl *uctrl) { |
| assert(uctrl); |
| |
| udev_ctrl_disconnect(uctrl); |
| |
| sd_event_source_unref(uctrl->event_source); |
| safe_close(uctrl->sock); |
| |
| sd_event_unref(uctrl->event); |
| return mfree(uctrl); |
| } |
| |
| DEFINE_TRIVIAL_REF_UNREF_FUNC(struct udev_ctrl, udev_ctrl, udev_ctrl_free); |
| |
| int udev_ctrl_cleanup(struct udev_ctrl *uctrl) { |
| if (!uctrl) |
| return 0; |
| if (uctrl->cleanup_socket) |
| sockaddr_un_unlink(&uctrl->saddr.un); |
| return 0; |
| } |
| |
| int udev_ctrl_attach_event(struct udev_ctrl *uctrl, sd_event *event) { |
| int r; |
| |
| assert_return(uctrl, -EINVAL); |
| assert_return(!uctrl->event, -EBUSY); |
| |
| if (event) |
| uctrl->event = sd_event_ref(event); |
| else { |
| r = sd_event_default(&uctrl->event); |
| if (r < 0) |
| return r; |
| } |
| |
| return 0; |
| } |
| |
| sd_event_source *udev_ctrl_get_event_source(struct udev_ctrl *uctrl) { |
| assert(uctrl); |
| |
| return uctrl->event_source; |
| } |
| |
| static void udev_ctrl_disconnect_and_listen_again(struct udev_ctrl *uctrl) { |
| udev_ctrl_disconnect(uctrl); |
| udev_ctrl_unref(uctrl); |
| (void) sd_event_source_set_enabled(uctrl->event_source, SD_EVENT_ON); |
| } |
| |
| DEFINE_TRIVIAL_CLEANUP_FUNC(struct udev_ctrl *, udev_ctrl_disconnect_and_listen_again); |
| |
| static int udev_ctrl_connection_event_handler(sd_event_source *s, int fd, uint32_t revents, void *userdata) { |
| _cleanup_(udev_ctrl_disconnect_and_listen_againp) struct udev_ctrl *uctrl = NULL; |
| struct udev_ctrl_msg_wire msg_wire; |
| struct iovec iov = IOVEC_MAKE(&msg_wire, sizeof(struct udev_ctrl_msg_wire)); |
| 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 cmsghdr *cmsg; |
| struct ucred *cred; |
| ssize_t size; |
| |
| assert(userdata); |
| |
| /* When UDEV_CTRL_EXIT is received, manager unref udev_ctrl object. |
| * To avoid the object freed, let's increment the refcount. */ |
| uctrl = udev_ctrl_ref(userdata); |
| |
| size = next_datagram_size_fd(fd); |
| if (size < 0) |
| return log_error_errno(size, "Failed to get size of message: %m"); |
| if (size == 0) |
| return 0; /* Client disconnects? */ |
| |
| size = recvmsg(fd, &smsg, 0); |
| if (size < 0) { |
| if (errno != EINTR) |
| return log_error_errno(errno, "Failed to receive ctrl message: %m"); |
| |
| return 0; |
| } |
| |
| cmsg_close_all(&smsg); |
| |
| cmsg = CMSG_FIRSTHDR(&smsg); |
| |
| if (!cmsg || cmsg->cmsg_type != SCM_CREDENTIALS) { |
| log_error("No sender credentials received, ignoring message"); |
| return 0; |
| } |
| |
| cred = (struct ucred *) CMSG_DATA(cmsg); |
| |
| if (cred->uid != 0) { |
| log_error("Invalid sender uid "UID_FMT", ignoring message", cred->uid); |
| return 0; |
| } |
| |
| if (msg_wire.magic != UDEV_CTRL_MAGIC) { |
| log_error("Message magic 0x%08x doesn't match, ignoring message", msg_wire.magic); |
| return 0; |
| } |
| |
| if (msg_wire.type == _UDEV_CTRL_END_MESSAGES) |
| return 0; |
| |
| if (uctrl->callback) |
| (void) uctrl->callback(uctrl, msg_wire.type, &msg_wire.value, uctrl->userdata); |
| |
| /* Do not disconnect and wait for next message. */ |
| uctrl = udev_ctrl_unref(uctrl); |
| return 0; |
| } |
| |
| static int udev_ctrl_event_handler(sd_event_source *s, int fd, uint32_t revents, void *userdata) { |
| struct udev_ctrl *uctrl = userdata; |
| _cleanup_close_ int sock = -1; |
| struct ucred ucred; |
| int r; |
| |
| assert(uctrl); |
| |
| sock = accept4(fd, NULL, NULL, SOCK_CLOEXEC|SOCK_NONBLOCK); |
| if (sock < 0) { |
| if (ERRNO_IS_ACCEPT_AGAIN(errno)) |
| return 0; |
| |
| return log_error_errno(errno, "Failed to accept ctrl connection: %m"); |
| } |
| |
| /* check peer credential of connection */ |
| r = getpeercred(sock, &ucred); |
| if (r < 0) { |
| log_error_errno(r, "Failed to receive credentials of ctrl connection: %m"); |
| return 0; |
| } |
| |
| if (ucred.uid > 0) { |
| log_error("Invalid sender uid "UID_FMT", closing connection", ucred.uid); |
| return 0; |
| } |
| |
| /* enable receiving of the sender credentials in the messages */ |
| r = setsockopt_int(sock, SOL_SOCKET, SO_PASSCRED, true); |
| if (r < 0) |
| log_warning_errno(r, "Failed to set SO_PASSCRED, ignoring: %m"); |
| |
| r = sd_event_add_io(uctrl->event, &uctrl->event_source_connect, sock, EPOLLIN, udev_ctrl_connection_event_handler, uctrl); |
| if (r < 0) { |
| log_error_errno(r, "Failed to create event source for udev control connection: %m"); |
| return 0; |
| } |
| |
| (void) sd_event_source_set_description(uctrl->event_source_connect, "udev-ctrl-connection"); |
| |
| /* Do not accept multiple connection. */ |
| (void) sd_event_source_set_enabled(uctrl->event_source, SD_EVENT_OFF); |
| |
| uctrl->sock_connect = TAKE_FD(sock); |
| return 0; |
| } |
| |
| int udev_ctrl_start(struct udev_ctrl *uctrl, udev_ctrl_handler_t callback, void *userdata) { |
| int r; |
| |
| assert(uctrl); |
| |
| if (!uctrl->event) { |
| r = udev_ctrl_attach_event(uctrl, NULL); |
| if (r < 0) |
| return r; |
| } |
| |
| r = udev_ctrl_enable_receiving(uctrl); |
| if (r < 0) |
| return r; |
| |
| uctrl->callback = callback; |
| uctrl->userdata = userdata; |
| |
| r = sd_event_add_io(uctrl->event, &uctrl->event_source, uctrl->sock, EPOLLIN, udev_ctrl_event_handler, uctrl); |
| if (r < 0) |
| return r; |
| |
| (void) sd_event_source_set_description(uctrl->event_source, "udev-ctrl"); |
| |
| return 0; |
| } |
| |
| int udev_ctrl_send(struct udev_ctrl *uctrl, enum udev_ctrl_msg_type type, int intval, const char *buf) { |
| struct udev_ctrl_msg_wire ctrl_msg_wire = { |
| .version = "udev-" STRINGIFY(PROJECT_VERSION), |
| .magic = UDEV_CTRL_MAGIC, |
| .type = type, |
| }; |
| |
| if (uctrl->maybe_disconnected) |
| return -ENOANO; /* to distinguish this from other errors. */ |
| |
| if (buf) |
| strscpy(ctrl_msg_wire.value.buf, sizeof(ctrl_msg_wire.value.buf), buf); |
| else |
| ctrl_msg_wire.value.intval = intval; |
| |
| if (!uctrl->connected) { |
| if (connect(uctrl->sock, &uctrl->saddr.sa, uctrl->addrlen) < 0) |
| return -errno; |
| uctrl->connected = true; |
| } |
| |
| if (send(uctrl->sock, &ctrl_msg_wire, sizeof(ctrl_msg_wire), 0) < 0) |
| return -errno; |
| |
| if (type == UDEV_CTRL_EXIT) |
| uctrl->maybe_disconnected = true; |
| |
| return 0; |
| } |
| |
| static int udev_ctrl_wait_io_handler(sd_event_source *s, int fd, uint32_t revents, void *userdata) { |
| return sd_event_exit(sd_event_source_get_event(s), 0); |
| } |
| |
| int udev_ctrl_wait(struct udev_ctrl *uctrl, usec_t timeout) { |
| _cleanup_(sd_event_source_unrefp) sd_event_source *source_io = NULL, *source_timeout = NULL; |
| int r; |
| |
| assert(uctrl); |
| |
| if (uctrl->sock < 0) |
| return 0; |
| if (!uctrl->connected) |
| return 0; |
| |
| if (!uctrl->maybe_disconnected) { |
| r = udev_ctrl_send(uctrl, _UDEV_CTRL_END_MESSAGES, 0, NULL); |
| if (r < 0) |
| return r; |
| } |
| |
| if (timeout == 0) |
| return 0; |
| |
| if (!uctrl->event) { |
| r = udev_ctrl_attach_event(uctrl, NULL); |
| if (r < 0) |
| return r; |
| } |
| |
| r = sd_event_add_io(uctrl->event, &source_io, uctrl->sock, EPOLLIN, udev_ctrl_wait_io_handler, NULL); |
| if (r < 0) |
| return r; |
| |
| (void) sd_event_source_set_description(uctrl->event_source, "udev-ctrl-wait-io"); |
| |
| if (timeout != USEC_INFINITY) { |
| r = sd_event_add_time(uctrl->event, &source_timeout, clock_boottime_or_monotonic(), |
| usec_add(now(clock_boottime_or_monotonic()), timeout), |
| 0, NULL, INT_TO_PTR(-ETIMEDOUT)); |
| if (r < 0) |
| return r; |
| |
| (void) sd_event_source_set_description(source_timeout, "udev-ctrl-wait-timeout"); |
| } |
| |
| return sd_event_loop(uctrl->event); |
| } |