diff options
Diffstat (limited to 'vendor/github.com/karalabe/hid/libusb/libusb/os/linux_netlink.c')
-rw-r--r-- | vendor/github.com/karalabe/hid/libusb/libusb/os/linux_netlink.c | 400 |
1 files changed, 400 insertions, 0 deletions
diff --git a/vendor/github.com/karalabe/hid/libusb/libusb/os/linux_netlink.c b/vendor/github.com/karalabe/hid/libusb/libusb/os/linux_netlink.c new file mode 100644 index 000000000..60cf3ad1b --- /dev/null +++ b/vendor/github.com/karalabe/hid/libusb/libusb/os/linux_netlink.c @@ -0,0 +1,400 @@ +/* -*- Mode: C; c-basic-offset:8 ; indent-tabs-mode:t -*- */ +/* + * Linux usbfs backend for libusb + * Copyright (C) 2007-2009 Daniel Drake <dsd@gentoo.org> + * Copyright (c) 2001 Johannes Erdfelt <johannes@erdfelt.com> + * Copyright (c) 2013 Nathan Hjelm <hjelmn@mac.com> + * Copyright (c) 2016 Chris Dickens <christopher.a.dickens@gmail.com> + * + * 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. + * + * This library is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with this library; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA + */ + +#include <config.h> + +#include <assert.h> +#include <errno.h> +#include <fcntl.h> +#include <poll.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <unistd.h> +#include <sys/types.h> + +#ifdef HAVE_ASM_TYPES_H +#include <asm/types.h> +#endif + +#include <sys/socket.h> +#include <linux/netlink.h> + +#include "libusbi.h" +#include "linux_usbfs.h" + +#define NL_GROUP_KERNEL 1 + +static int linux_netlink_socket = -1; +static int netlink_control_pipe[2] = { -1, -1 }; +static pthread_t libusb_linux_event_thread; + +static void *linux_netlink_event_thread_main(void *arg); + +static int set_fd_cloexec_nb(int fd) +{ + int flags; + +#if defined(FD_CLOEXEC) + flags = fcntl(fd, F_GETFD); + if (flags == -1) { + usbi_err(NULL, "failed to get netlink fd flags (%d)", errno); + return -1; + } + + if (!(flags & FD_CLOEXEC)) { + if (fcntl(fd, F_SETFD, flags | FD_CLOEXEC) == -1) { + usbi_err(NULL, "failed to set netlink fd flags (%d)", errno); + return -1; + } + } +#endif + + flags = fcntl(fd, F_GETFL); + if (flags == -1) { + usbi_err(NULL, "failed to get netlink fd status flags (%d)", errno); + return -1; + } + + if (!(flags & O_NONBLOCK)) { + if (fcntl(fd, F_SETFL, flags | O_NONBLOCK) == -1) { + usbi_err(NULL, "failed to set netlink fd status flags (%d)", errno); + return -1; + } + } + + return 0; +} + +int linux_netlink_start_event_monitor(void) +{ + struct sockaddr_nl sa_nl = { .nl_family = AF_NETLINK, .nl_groups = NL_GROUP_KERNEL }; + int socktype = SOCK_RAW; + int opt = 1; + int ret; + +#if defined(SOCK_CLOEXEC) + socktype |= SOCK_CLOEXEC; +#endif +#if defined(SOCK_NONBLOCK) + socktype |= SOCK_NONBLOCK; +#endif + + linux_netlink_socket = socket(PF_NETLINK, socktype, NETLINK_KOBJECT_UEVENT); + if (linux_netlink_socket == -1 && errno == EINVAL) { + usbi_dbg("failed to create netlink socket of type %d, attempting SOCK_RAW", socktype); + linux_netlink_socket = socket(PF_NETLINK, SOCK_RAW, NETLINK_KOBJECT_UEVENT); + } + + if (linux_netlink_socket == -1) { + usbi_err(NULL, "failed to create netlink socket (%d)", errno); + goto err; + } + + ret = set_fd_cloexec_nb(linux_netlink_socket); + if (ret == -1) + goto err_close_socket; + + ret = bind(linux_netlink_socket, (struct sockaddr *)&sa_nl, sizeof(sa_nl)); + if (ret == -1) { + usbi_err(NULL, "failed to bind netlink socket (%d)", errno); + goto err_close_socket; + } + + ret = setsockopt(linux_netlink_socket, SOL_SOCKET, SO_PASSCRED, &opt, sizeof(opt)); + if (ret == -1) { + usbi_err(NULL, "failed to set netlink socket SO_PASSCRED option (%d)", errno); + goto err_close_socket; + } + + ret = usbi_pipe(netlink_control_pipe); + if (ret) { + usbi_err(NULL, "failed to create netlink control pipe"); + goto err_close_socket; + } + + ret = pthread_create(&libusb_linux_event_thread, NULL, linux_netlink_event_thread_main, NULL); + if (ret != 0) { + usbi_err(NULL, "failed to create netlink event thread (%d)", ret); + goto err_close_pipe; + } + + return LIBUSB_SUCCESS; + +err_close_pipe: + close(netlink_control_pipe[0]); + close(netlink_control_pipe[1]); + netlink_control_pipe[0] = -1; + netlink_control_pipe[1] = -1; +err_close_socket: + close(linux_netlink_socket); + linux_netlink_socket = -1; +err: + return LIBUSB_ERROR_OTHER; +} + +int linux_netlink_stop_event_monitor(void) +{ + char dummy = 1; + ssize_t r; + + assert(linux_netlink_socket != -1); + + /* Write some dummy data to the control pipe and + * wait for the thread to exit */ + r = usbi_write(netlink_control_pipe[1], &dummy, sizeof(dummy)); + if (r <= 0) + usbi_warn(NULL, "netlink control pipe signal failed"); + + pthread_join(libusb_linux_event_thread, NULL); + + close(linux_netlink_socket); + linux_netlink_socket = -1; + + /* close and reset control pipe */ + close(netlink_control_pipe[0]); + close(netlink_control_pipe[1]); + netlink_control_pipe[0] = -1; + netlink_control_pipe[1] = -1; + + return LIBUSB_SUCCESS; +} + +static const char *netlink_message_parse(const char *buffer, size_t len, const char *key) +{ + const char *end = buffer + len; + size_t keylen = strlen(key); + + while (buffer < end && *buffer) { + if (strncmp(buffer, key, keylen) == 0 && buffer[keylen] == '=') + return buffer + keylen + 1; + buffer += strlen(buffer) + 1; + } + + return NULL; +} + +/* parse parts of netlink message common to both libudev and the kernel */ +static int linux_netlink_parse(const char *buffer, size_t len, int *detached, + const char **sys_name, uint8_t *busnum, uint8_t *devaddr) +{ + const char *tmp, *slash; + + errno = 0; + + *sys_name = NULL; + *detached = 0; + *busnum = 0; + *devaddr = 0; + + tmp = netlink_message_parse(buffer, len, "ACTION"); + if (!tmp) { + return -1; + } else if (strcmp(tmp, "remove") == 0) { + *detached = 1; + } else if (strcmp(tmp, "add") != 0) { + usbi_dbg("unknown device action %s", tmp); + return -1; + } + + /* check that this is a usb message */ + tmp = netlink_message_parse(buffer, len, "SUBSYSTEM"); + if (!tmp || strcmp(tmp, "usb") != 0) { + /* not usb. ignore */ + return -1; + } + + /* check that this is an actual usb device */ + tmp = netlink_message_parse(buffer, len, "DEVTYPE"); + if (!tmp || strcmp(tmp, "usb_device") != 0) { + /* not usb. ignore */ + return -1; + } + + tmp = netlink_message_parse(buffer, len, "BUSNUM"); + if (tmp) { + *busnum = (uint8_t)(strtoul(tmp, NULL, 10) & 0xff); + if (errno) { + errno = 0; + return -1; + } + + tmp = netlink_message_parse(buffer, len, "DEVNUM"); + if (NULL == tmp) + return -1; + + *devaddr = (uint8_t)(strtoul(tmp, NULL, 10) & 0xff); + if (errno) { + errno = 0; + return -1; + } + } else { + /* no bus number. try "DEVICE" */ + tmp = netlink_message_parse(buffer, len, "DEVICE"); + if (!tmp) { + /* not usb. ignore */ + return -1; + } + + /* Parse a device path such as /dev/bus/usb/003/004 */ + slash = strrchr(tmp, '/'); + if (!slash) + return -1; + + *busnum = (uint8_t)(strtoul(slash - 3, NULL, 10) & 0xff); + if (errno) { + errno = 0; + return -1; + } + + *devaddr = (uint8_t)(strtoul(slash + 1, NULL, 10) & 0xff); + if (errno) { + errno = 0; + return -1; + } + + return 0; + } + + tmp = netlink_message_parse(buffer, len, "DEVPATH"); + if (!tmp) + return -1; + + slash = strrchr(tmp, '/'); + if (slash) + *sys_name = slash + 1; + + /* found a usb device */ + return 0; +} + +static int linux_netlink_read_message(void) +{ + char cred_buffer[CMSG_SPACE(sizeof(struct ucred))]; + char msg_buffer[2048]; + const char *sys_name = NULL; + uint8_t busnum, devaddr; + int detached, r; + ssize_t len; + struct cmsghdr *cmsg; + struct ucred *cred; + struct sockaddr_nl sa_nl; + struct iovec iov = { .iov_base = msg_buffer, .iov_len = sizeof(msg_buffer) }; + struct msghdr msg = { + .msg_iov = &iov, .msg_iovlen = 1, + .msg_control = cred_buffer, .msg_controllen = sizeof(cred_buffer), + .msg_name = &sa_nl, .msg_namelen = sizeof(sa_nl) + }; + + /* read netlink message */ + len = recvmsg(linux_netlink_socket, &msg, 0); + if (len == -1) { + if (errno != EAGAIN && errno != EINTR) + usbi_err(NULL, "error receiving message from netlink (%d)", errno); + return -1; + } + + if (len < 32 || (msg.msg_flags & MSG_TRUNC)) { + usbi_err(NULL, "invalid netlink message length"); + return -1; + } + + if (sa_nl.nl_groups != NL_GROUP_KERNEL || sa_nl.nl_pid != 0) { + usbi_dbg("ignoring netlink message from unknown group/PID (%u/%u)", + (unsigned int)sa_nl.nl_groups, (unsigned int)sa_nl.nl_pid); + return -1; + } + + cmsg = CMSG_FIRSTHDR(&msg); + if (!cmsg || cmsg->cmsg_type != SCM_CREDENTIALS) { + usbi_dbg("ignoring netlink message with no sender credentials"); + return -1; + } + + cred = (struct ucred *)CMSG_DATA(cmsg); + if (cred->uid != 0) { + usbi_dbg("ignoring netlink message with non-zero sender UID %u", (unsigned int)cred->uid); + return -1; + } + + r = linux_netlink_parse(msg_buffer, (size_t)len, &detached, &sys_name, &busnum, &devaddr); + if (r) + return r; + + usbi_dbg("netlink hotplug found device busnum: %hhu, devaddr: %hhu, sys_name: %s, removed: %s", + busnum, devaddr, sys_name, detached ? "yes" : "no"); + + /* signal device is available (or not) to all contexts */ + if (detached) + linux_device_disconnected(busnum, devaddr); + else + linux_hotplug_enumerate(busnum, devaddr, sys_name); + + return 0; +} + +static void *linux_netlink_event_thread_main(void *arg) +{ + char dummy; + ssize_t r; + struct pollfd fds[] = { + { .fd = netlink_control_pipe[0], + .events = POLLIN }, + { .fd = linux_netlink_socket, + .events = POLLIN }, + }; + + UNUSED(arg); + + usbi_dbg("netlink event thread entering"); + + while (poll(fds, 2, -1) >= 0) { + if (fds[0].revents & POLLIN) { + /* activity on control pipe, read the byte and exit */ + r = usbi_read(netlink_control_pipe[0], &dummy, sizeof(dummy)); + if (r <= 0) + usbi_warn(NULL, "netlink control pipe read failed"); + break; + } + if (fds[1].revents & POLLIN) { + usbi_mutex_static_lock(&linux_hotplug_lock); + linux_netlink_read_message(); + usbi_mutex_static_unlock(&linux_hotplug_lock); + } + } + + usbi_dbg("netlink event thread exiting"); + + return NULL; +} + +void linux_netlink_hotplug_poll(void) +{ + int r; + + usbi_mutex_static_lock(&linux_hotplug_lock); + do { + r = linux_netlink_read_message(); + } while (r == 0); + usbi_mutex_static_unlock(&linux_hotplug_lock); +} |