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-rw-r--r--src/udev/udev-ctrl.c353
1 files changed, 353 insertions, 0 deletions
diff --git a/src/udev/udev-ctrl.c b/src/udev/udev-ctrl.c
new file mode 100644
index 0000000..2871634
--- /dev/null
+++ b/src/udev/udev-ctrl.c
@@ -0,0 +1,353 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <errno.h>
+#include <poll.h>
+#include <stddef.h>
+#include <stdlib.h>
+#include <string.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 "iovec-util.h"
+#include "socket-util.h"
+#include "strxcpyx.h"
+#include "udev-ctrl.h"
+
+/* wire protocol magic must match */
+#define UDEV_CTRL_MAGIC 0xdead1dea
+
+typedef struct UdevCtrlMessageWire {
+ char version[16];
+ unsigned magic;
+ UdevCtrlMessageType type;
+ UdevCtrlMessageValue value;
+} UdevCtrlMessageWire;
+
+struct UdevCtrl {
+ unsigned n_ref;
+ int sock;
+ int sock_connect;
+ union sockaddr_union saddr;
+ socklen_t addrlen;
+ bool bound;
+ bool connected;
+ 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(UdevCtrl **ret, int fd) {
+ _cleanup_close_ int sock = -EBADF;
+ UdevCtrl *uctrl;
+
+ assert(ret);
+
+ if (fd < 0) {
+ sock = socket(AF_UNIX, SOCK_SEQPACKET|SOCK_NONBLOCK|SOCK_CLOEXEC, 0);
+ if (sock < 0)
+ return log_error_errno(errno, "Failed to create socket: %m");
+ }
+
+ uctrl = new(UdevCtrl, 1);
+ if (!uctrl)
+ return -ENOMEM;
+
+ *uctrl = (UdevCtrl) {
+ .n_ref = 1,
+ .sock = fd >= 0 ? fd : TAKE_FD(sock),
+ .sock_connect = -EBADF,
+ .bound = fd >= 0,
+ };
+
+ 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(UdevCtrl *uctrl) {
+ assert(uctrl);
+
+ if (uctrl->bound)
+ return 0;
+
+ (void) sockaddr_un_unlink(&uctrl->saddr.un);
+ if (bind(uctrl->sock, &uctrl->saddr.sa, uctrl->addrlen) < 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;
+ return 0;
+}
+
+static void udev_ctrl_disconnect(UdevCtrl *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 UdevCtrl *udev_ctrl_free(UdevCtrl *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(UdevCtrl, udev_ctrl, udev_ctrl_free);
+
+int udev_ctrl_attach_event(UdevCtrl *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(UdevCtrl *uctrl) {
+ assert(uctrl);
+
+ return uctrl->event_source;
+}
+
+static void udev_ctrl_disconnect_and_listen_again(UdevCtrl *uctrl) {
+ udev_ctrl_disconnect(uctrl);
+ udev_ctrl_unref(uctrl);
+ (void) sd_event_source_set_enabled(uctrl->event_source, SD_EVENT_ON);
+ /* We don't return NULL here because uctrl is not freed */
+}
+
+DEFINE_TRIVIAL_CLEANUP_FUNC_FULL(UdevCtrl*, udev_ctrl_disconnect_and_listen_again, NULL);
+
+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) UdevCtrl *uctrl = NULL;
+ UdevCtrlMessageWire msg_wire;
+ struct iovec iov = IOVEC_MAKE(&msg_wire, sizeof(UdevCtrlMessageWire));
+ CMSG_BUFFER_TYPE(CMSG_SPACE(sizeof(struct ucred))) control;
+ struct msghdr smsg = {
+ .msg_iov = &iov,
+ .msg_iovlen = 1,
+ .msg_control = &control,
+ .msg_controllen = sizeof(control),
+ };
+ 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_safe(fd, &smsg, 0);
+ if (size == -EINTR)
+ return 0;
+ if (size < 0)
+ return log_error_errno(size, "Failed to receive ctrl message: %m");
+
+ cmsg_close_all(&smsg);
+
+ cred = CMSG_FIND_DATA(&smsg, SOL_SOCKET, SCM_CREDENTIALS, struct ucred);
+ if (!cred) {
+ log_error("No sender credentials received, ignoring message");
+ return 0;
+ }
+
+ 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) {
+ UdevCtrl *uctrl = ASSERT_PTR(userdata);
+ _cleanup_close_ int sock = -EBADF;
+ struct ucred ucred;
+ int r;
+
+ 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(UdevCtrl *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(UdevCtrl *uctrl, UdevCtrlMessageType type, const void *data) {
+ UdevCtrlMessageWire ctrl_msg_wire = {
+ .version = "udev-" STRINGIFY(PROJECT_VERSION),
+ .magic = UDEV_CTRL_MAGIC,
+ .type = type,
+ };
+
+ if (type == UDEV_CTRL_SET_ENV) {
+ assert(data);
+ strscpy(ctrl_msg_wire.value.buf, sizeof(ctrl_msg_wire.value.buf), data);
+ } else if (IN_SET(type, UDEV_CTRL_SET_LOG_LEVEL, UDEV_CTRL_SET_CHILDREN_MAX))
+ ctrl_msg_wire.value.intval = PTR_TO_INT(data);
+
+ 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;
+
+ return 0;
+}
+
+int udev_ctrl_wait(UdevCtrl *uctrl, usec_t timeout) {
+ _cleanup_(sd_event_source_disable_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;
+
+ r = udev_ctrl_send(uctrl, _UDEV_CTRL_END_MESSAGES, 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, NULL, INT_TO_PTR(0));
+ if (r < 0)
+ return r;
+
+ (void) sd_event_source_set_description(source_io, "udev-ctrl-wait-io");
+
+ if (timeout != USEC_INFINITY) {
+ r = sd_event_add_time_relative(
+ uctrl->event, &source_timeout, CLOCK_BOOTTIME,
+ 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);
+}
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