/* 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 #include #include #include #include #include #include #include #include "alloc-util.h" #include "fd-util.h" #include "format-util.h" #include "socket-util.h" #include "udev.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 int magic; enum udev_ctrl_msg_type type; union { int intval; char buf[256]; }; }; struct udev_ctrl_msg { int refcount; struct udev_ctrl_connection *conn; struct udev_ctrl_msg_wire ctrl_msg_wire; }; struct udev_ctrl { int refcount; struct udev *udev; int sock; union sockaddr_union saddr; socklen_t addrlen; bool bound; bool cleanup_socket; bool connected; }; struct udev_ctrl_connection { int refcount; struct udev_ctrl *uctrl; int sock; }; struct udev_ctrl *udev_ctrl_new_from_fd(struct udev *udev, int fd) { struct udev_ctrl *uctrl; const int on = 1; int r; uctrl = new0(struct udev_ctrl, 1); if (uctrl == NULL) return NULL; uctrl->refcount = 1; uctrl->udev = udev; 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(uctrl->sock, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on)); if (r < 0) log_warning_errno(errno, "could not set SO_PASSCRED: %m"); uctrl->saddr.un.sun_family = AF_LOCAL; strscpy(uctrl->saddr.un.sun_path, sizeof(uctrl->saddr.un.sun_path), "/run/udev/control"); uctrl->addrlen = SOCKADDR_UN_LEN(uctrl->saddr.un); return uctrl; } struct udev_ctrl *udev_ctrl_new(struct udev *udev) { return udev_ctrl_new_from_fd(udev, -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) { unlink(uctrl->saddr.un.sun_path); 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; } struct udev *udev_ctrl_get_udev(struct udev_ctrl *uctrl) { return uctrl->udev; } static struct udev_ctrl *udev_ctrl_ref(struct udev_ctrl *uctrl) { if (uctrl) uctrl->refcount++; return uctrl; } struct udev_ctrl *udev_ctrl_unref(struct udev_ctrl *uctrl) { if (uctrl && -- uctrl->refcount == 0) { if (uctrl->sock >= 0) close(uctrl->sock); free(uctrl); } return NULL; } int udev_ctrl_cleanup(struct udev_ctrl *uctrl) { if (uctrl == NULL) return 0; if (uctrl->cleanup_socket) unlink(uctrl->saddr.un.sun_path); 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 = {}; const int on = 1; int r; conn = new(struct udev_ctrl_connection, 1); if (conn == NULL) return NULL; conn->refcount = 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(conn->sock, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on)); if (r < 0) log_warning_errno(errno, "could not set SO_PASSCRED: %m"); udev_ctrl_ref(uctrl); return conn; err: if (conn->sock >= 0) close(conn->sock); return mfree(conn); } struct udev_ctrl_connection *udev_ctrl_connection_ref(struct udev_ctrl_connection *conn) { if (conn == NULL) return NULL; conn->refcount++; return conn; } struct udev_ctrl_connection *udev_ctrl_connection_unref(struct udev_ctrl_connection *conn) { if (conn && -- conn->refcount == 0) { if (conn->sock >= 0) close(conn->sock); udev_ctrl_unref(conn->uctrl); free(conn); } return NULL; } 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->refcount = 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; } struct udev_ctrl_msg *udev_ctrl_msg_unref(struct udev_ctrl_msg *ctrl_msg) { if (ctrl_msg && -- ctrl_msg->refcount == 0) { udev_ctrl_connection_unref(ctrl_msg->conn); free(ctrl_msg); } return NULL; } 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; }