1 /* -*- Mode: C; c-basic-offset:8 ; indent-tabs-mode:t -*- */ 2 /* 3 * Linux usbfs backend for libusb 4 * Copyright (C) 2007-2009 Daniel Drake <dsd (at) gentoo.org> 5 * Copyright (c) 2001 Johannes Erdfelt <johannes (at) erdfelt.com> 6 * Copyright (c) 2012-2013 Nathan Hjelm <hjelmn (at) mac.com> 7 * 8 * This library is free software; you can redistribute it and/or 9 * modify it under the terms of the GNU Lesser General Public 10 * License as published by the Free Software Foundation; either 11 * version 2.1 of the License, or (at your option) any later version. 12 * 13 * This library is distributed in the hope that it will be useful, 14 * but WITHOUT ANY WARRANTY; without even the implied warranty of 15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 16 * Lesser General Public License for more details. 17 * 18 * You should have received a copy of the GNU Lesser General Public 19 * License along with this library; if not, write to the Free Software 20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 21 */ 22 23 #include <config.h> 24 25 #include <assert.h> 26 #include <ctype.h> 27 #include <dirent.h> 28 #include <errno.h> 29 #include <fcntl.h> 30 #include <poll.h> 31 #include <stdio.h> 32 #include <stdlib.h> 33 #include <string.h> 34 #include <sys/ioctl.h> 35 #include <sys/stat.h> 36 #include <sys/types.h> 37 #include <sys/utsname.h> 38 #include <sys/socket.h> 39 #include <unistd.h> 40 #include <libudev.h> 41 42 #include "libusbi.h" 43 #include "linux_usbfs.h" 44 45 /* udev context */ 46 static struct udev *udev_ctx = NULL; 47 static int udev_monitor_fd = -1; 48 static int udev_control_pipe[2] = {-1, -1}; 49 static struct udev_monitor *udev_monitor = NULL; 50 static pthread_t linux_event_thread; 51 52 static void udev_hotplug_event(struct udev_device* udev_dev); 53 static void *linux_udev_event_thread_main(void *arg); 54 55 int linux_udev_start_event_monitor(void) 56 { 57 int r; 58 59 assert(udev_ctx == NULL); 60 udev_ctx = udev_new(); 61 if (!udev_ctx) { 62 usbi_err(NULL, "could not create udev context"); 63 goto err; 64 } 65 66 udev_monitor = udev_monitor_new_from_netlink(udev_ctx, "udev"); 67 if (!udev_monitor) { 68 usbi_err(NULL, "could not initialize udev monitor"); 69 goto err_free_ctx; 70 } 71 72 r = udev_monitor_filter_add_match_subsystem_devtype(udev_monitor, "usb", "usb_device"); 73 if (r) { 74 usbi_err(NULL, "could not initialize udev monitor filter for \"usb\" subsystem"); 75 goto err_free_monitor; 76 } 77 78 if (udev_monitor_enable_receiving(udev_monitor)) { 79 usbi_err(NULL, "failed to enable the udev monitor"); 80 goto err_free_monitor; 81 } 82 83 udev_monitor_fd = udev_monitor_get_fd(udev_monitor); 84 85 /* Some older versions of udev are not non-blocking by default, 86 * so make sure this is set */ 87 r = fcntl(udev_monitor_fd, F_GETFL); 88 if (r == -1) { 89 usbi_err(NULL, "getting udev monitor fd flags (%d)", errno); 90 goto err_free_monitor; 91 } 92 r = fcntl(udev_monitor_fd, F_SETFL, r | O_NONBLOCK); 93 if (r) { 94 usbi_err(NULL, "setting udev monitor fd flags (%d)", errno); 95 goto err_free_monitor; 96 } 97 98 r = usbi_pipe(udev_control_pipe); 99 if (r) { 100 usbi_err(NULL, "could not create udev control pipe"); 101 goto err_free_monitor; 102 } 103 104 r = pthread_create(&linux_event_thread, NULL, linux_udev_event_thread_main, NULL); 105 if (r) { 106 usbi_err(NULL, "creating hotplug event thread (%d)", r); 107 goto err_close_pipe; 108 } 109 110 return LIBUSB_SUCCESS; 111 112 err_close_pipe: 113 close(udev_control_pipe[0]); 114 close(udev_control_pipe[1]); 115 err_free_monitor: 116 udev_monitor_unref(udev_monitor); 117 udev_monitor = NULL; 118 udev_monitor_fd = -1; 119 err_free_ctx: 120 udev_unref(udev_ctx); 121 err: 122 udev_ctx = NULL; 123 return LIBUSB_ERROR_OTHER; 124 } 125 126 int linux_udev_stop_event_monitor(void) 127 { 128 char dummy = 1; 129 int r; 130 131 assert(udev_ctx != NULL); 132 assert(udev_monitor != NULL); 133 assert(udev_monitor_fd != -1); 134 135 /* Write some dummy data to the control pipe and 136 * wait for the thread to exit */ 137 r = usbi_write(udev_control_pipe[1], &dummy, sizeof(dummy)); 138 if (r <= 0) { 139 usbi_warn(NULL, "udev control pipe signal failed"); 140 } 141 pthread_join(linux_event_thread, NULL); 142 143 /* Release the udev monitor */ 144 udev_monitor_unref(udev_monitor); 145 udev_monitor = NULL; 146 udev_monitor_fd = -1; 147 148 /* Clean up the udev context */ 149 udev_unref(udev_ctx); 150 udev_ctx = NULL; 151 152 /* close and reset control pipe */ 153 close(udev_control_pipe[0]); 154 close(udev_control_pipe[1]); 155 udev_control_pipe[0] = -1; 156 udev_control_pipe[1] = -1; 157 158 return LIBUSB_SUCCESS; 159 } 160 161 static void *linux_udev_event_thread_main(void *arg) 162 { 163 char dummy; 164 int r; 165 struct udev_device* udev_dev; 166 struct pollfd fds[] = { 167 {.fd = udev_control_pipe[0], 168 .events = POLLIN}, 169 {.fd = udev_monitor_fd, 170 .events = POLLIN}, 171 }; 172 173 usbi_dbg("udev event thread entering."); 174 175 while (poll(fds, 2, -1) >= 0) { 176 if (fds[0].revents & POLLIN) { 177 /* activity on control pipe, read the byte and exit */ 178 r = usbi_read(udev_control_pipe[0], &dummy, sizeof(dummy)); 179 if (r <= 0) { 180 usbi_warn(NULL, "udev control pipe read failed"); 181 } 182 break; 183 } 184 if (fds[1].revents & POLLIN) { 185 usbi_mutex_static_lock(&linux_hotplug_lock); 186 udev_dev = udev_monitor_receive_device(udev_monitor); 187 if (udev_dev) 188 udev_hotplug_event(udev_dev); 189 usbi_mutex_static_unlock(&linux_hotplug_lock); 190 } 191 } 192 193 usbi_dbg("udev event thread exiting"); 194 195 return NULL; 196 } 197 198 static int udev_device_info(struct libusb_context *ctx, int detached, 199 struct udev_device *udev_dev, uint8_t *busnum, 200 uint8_t *devaddr, const char **sys_name) { 201 const char *dev_node; 202 203 dev_node = udev_device_get_devnode(udev_dev); 204 if (!dev_node) { 205 return LIBUSB_ERROR_OTHER; 206 } 207 208 *sys_name = udev_device_get_sysname(udev_dev); 209 if (!*sys_name) { 210 return LIBUSB_ERROR_OTHER; 211 } 212 213 return linux_get_device_address(ctx, detached, busnum, devaddr, 214 dev_node, *sys_name); 215 } 216 217 static void udev_hotplug_event(struct udev_device* udev_dev) 218 { 219 const char* udev_action; 220 const char* sys_name = NULL; 221 uint8_t busnum = 0, devaddr = 0; 222 int detached; 223 int r; 224 225 do { 226 udev_action = udev_device_get_action(udev_dev); 227 if (!udev_action) { 228 break; 229 } 230 231 detached = !strncmp(udev_action, "remove", 6); 232 233 r = udev_device_info(NULL, detached, udev_dev, &busnum, &devaddr, &sys_name); 234 if (LIBUSB_SUCCESS != r) { 235 break; 236 } 237 238 usbi_dbg("udev hotplug event. action: %s.", udev_action); 239 240 if (strncmp(udev_action, "add", 3) == 0) { 241 linux_hotplug_enumerate(busnum, devaddr, sys_name); 242 } else if (detached) { 243 linux_device_disconnected(busnum, devaddr); 244 } else { 245 usbi_err(NULL, "ignoring udev action %s", udev_action); 246 } 247 } while (0); 248 249 udev_device_unref(udev_dev); 250 } 251 252 int linux_udev_scan_devices(struct libusb_context *ctx) 253 { 254 struct udev_enumerate *enumerator; 255 struct udev_list_entry *devices, *entry; 256 struct udev_device *udev_dev; 257 const char *sys_name; 258 int r; 259 260 assert(udev_ctx != NULL); 261 262 enumerator = udev_enumerate_new(udev_ctx); 263 if (NULL == enumerator) { 264 usbi_err(ctx, "error creating udev enumerator"); 265 return LIBUSB_ERROR_OTHER; 266 } 267 268 udev_enumerate_add_match_subsystem(enumerator, "usb"); 269 udev_enumerate_add_match_property(enumerator, "DEVTYPE", "usb_device"); 270 udev_enumerate_scan_devices(enumerator); 271 devices = udev_enumerate_get_list_entry(enumerator); 272 273 udev_list_entry_foreach(entry, devices) { 274 const char *path = udev_list_entry_get_name(entry); 275 uint8_t busnum = 0, devaddr = 0; 276 277 udev_dev = udev_device_new_from_syspath(udev_ctx, path); 278 279 r = udev_device_info(ctx, 0, udev_dev, &busnum, &devaddr, &sys_name); 280 if (r) { 281 udev_device_unref(udev_dev); 282 continue; 283 } 284 285 linux_enumerate_device(ctx, busnum, devaddr, sys_name); 286 udev_device_unref(udev_dev); 287 } 288 289 udev_enumerate_unref(enumerator); 290 291 return LIBUSB_SUCCESS; 292 } 293 294 void linux_udev_hotplug_poll(void) 295 { 296 struct udev_device* udev_dev; 297 298 usbi_mutex_static_lock(&linux_hotplug_lock); 299 do { 300 udev_dev = udev_monitor_receive_device(udev_monitor); 301 if (udev_dev) { 302 usbi_dbg("Handling hotplug event from hotplug_poll"); 303 udev_hotplug_event(udev_dev); 304 } 305 } while (udev_dev); 306 usbi_mutex_static_unlock(&linux_hotplug_lock); 307 } 308
