libudev/libudev-ctrl.c

   1 /*
   2  * libudev - interface to udev device information
   3  *
   4  * Copyright (C) 2008 Kay Sievers <kay.sievers@vrfy.org>
   5  *
   6  * This library is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2.1 of the License, or (at your option) any later version.
  10  */
  11
  12 #include <errno.h>
  13 #include <stdio.h>
  14 #include <stdlib.h>
  15 #include <stddef.h>
  16 #include <string.h>
  17 #include <unistd.h>
  18 #include <sys/types.h>
  19 #include <sys/socket.h>
  20 #include <sys/un.h>
  21
  22 #include "libudev.h"
  23 #include "libudev-private.h"
  24
  25 /* wire protocol magic must match */
  26 #define UDEV_CTRL_MAGIC                         0xdead1dea
  27
  28 enum udev_ctrl_msg_type {
  29         UDEV_CTRL_UNKNOWN,
  30         UDEV_CTRL_SET_LOG_LEVEL,
  31         UDEV_CTRL_STOP_EXEC_QUEUE,
  32         UDEV_CTRL_START_EXEC_QUEUE,
  33         UDEV_CTRL_RELOAD_RULES,
  34         UDEV_CTRL_SET_ENV,
  35         UDEV_CTRL_SET_CHILDREN_MAX,
  36         UDEV_CTRL_SETTLE,
  37 };
  38
  39 struct udev_ctrl_msg_wire {
  40         char version[16];
  41         unsigned int magic;
  42         enum udev_ctrl_msg_type type;
  43         union {
  44                 int intval;
  45                 char buf[256];
  46         };
  47 };
  48
  49 struct udev_ctrl_msg {
  50         int refcount;
  51         struct udev_ctrl *uctrl;
  52         struct udev_ctrl_msg_wire ctrl_msg_wire;
  53         pid_t pid;
  54 };
  55
  56 struct udev_ctrl {
  57         int refcount;
  58         struct udev *udev;
  59         int sock;
  60         struct sockaddr_un saddr;
  61         socklen_t addrlen;
  62 };
  63
  64 static struct udev_ctrl *udev_ctrl_new(struct udev *udev)
  65 {
  66         struct udev_ctrl *uctrl;
  67
  68         uctrl = calloc(1, sizeof(struct udev_ctrl));
  69         if (uctrl == NULL)
  70                 return NULL;
  71         uctrl->refcount = 1;
  72         uctrl->udev = udev;
  73         return uctrl;
  74 }
  75
  76 struct udev_ctrl *udev_ctrl_new_from_socket(struct udev *udev, const char *socket_path)
  77 {
  78         struct udev_ctrl *uctrl;
  79
  80         uctrl = udev_ctrl_new(udev);
  81         if (uctrl == NULL)
  82                 return NULL;
  83
  84         uctrl->sock = socket(AF_LOCAL, SOCK_DGRAM, 0);
  85         if (uctrl->sock < 0) {
  86                 err(udev, "error getting socket: %m\n");
  87                 udev_ctrl_unref(uctrl);
  88                 return NULL;
  89         }
  90
  91         uctrl->saddr.sun_family = AF_LOCAL;
  92         strcpy(uctrl->saddr.sun_path, socket_path);
  93         uctrl->addrlen = offsetof(struct sockaddr_un, sun_path) + strlen(uctrl->saddr.sun_path);
  94         /* translate leading '@' to abstract namespace */
  95         if (uctrl->saddr.sun_path[0] == '@')
  96                 uctrl->saddr.sun_path[0] = '\0';
  97         return uctrl;
  98 }
  99
 100 struct udev_ctrl *udev_ctrl_new_from_fd(struct udev *udev, int fd)
 101 {
 102         struct udev_ctrl *uctrl;
 103
 104         uctrl = udev_ctrl_new(udev);
 105         if (uctrl == NULL)
 106                 return NULL;
 107         uctrl->sock = fd;
 108
 109         return uctrl;
 110 }
 111
 112 int udev_ctrl_enable_receiving(struct udev_ctrl *uctrl)
 113 {
 114         int err;
 115         const int on = 1;
 116
 117         if (uctrl->addrlen > 0) {
 118                 err = bind(uctrl->sock, (struct sockaddr *)&uctrl->saddr, uctrl->addrlen);
 119                 if (err < 0) {
 120                         err(uctrl->udev, "bind failed: %m\n");
 121                         return err;
 122                 }
 123         }
 124
 125         /* enable receiving of the sender credentials */
 126         setsockopt(uctrl->sock, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on));
 127         return 0;
 128 }
 129
 130 struct udev *udev_ctrl_get_udev(struct udev_ctrl *uctrl)
 131 {
 132         return uctrl->udev;
 133 }
 134
 135 struct udev_ctrl *udev_ctrl_ref(struct udev_ctrl *uctrl)
 136 {
 137         if (uctrl == NULL)
 138                 return NULL;
 139         uctrl->refcount++;
 140         return uctrl;
 141 }
 142
 143 void udev_ctrl_unref(struct udev_ctrl *uctrl)
 144 {
 145         if (uctrl == NULL)
 146                 return;
 147         uctrl->refcount--;
 148         if (uctrl->refcount > 0)
 149                 return;
 150         if (uctrl->sock >= 0)
 151                 close(uctrl->sock);
 152         free(uctrl);
 153 }
 154
 155 int udev_ctrl_get_fd(struct udev_ctrl *uctrl)
 156 {
 157         if (uctrl == NULL)
 158                 return -1;
 159         return uctrl->sock;
 160 }
 161
 162 static int ctrl_send(struct udev_ctrl *uctrl, enum udev_ctrl_msg_type type, int intval, const char *buf)
 163 {
 164         struct udev_ctrl_msg_wire ctrl_msg_wire;
 165         int err;
 166
 167         memset(&ctrl_msg_wire, 0x00, sizeof(struct udev_ctrl_msg_wire));
 168         strcpy(ctrl_msg_wire.version, "udev-" VERSION);
 169         ctrl_msg_wire.magic = UDEV_CTRL_MAGIC;
 170         ctrl_msg_wire.type = type;
 171
 172         if (buf != NULL)
 173                 util_strscpy(ctrl_msg_wire.buf, sizeof(ctrl_msg_wire.buf), buf);
 174         else
 175                 ctrl_msg_wire.intval = intval;
 176
 177         err = sendto(uctrl->sock, &ctrl_msg_wire, sizeof(ctrl_msg_wire), 0,
 178                      (struct sockaddr *)&uctrl->saddr, uctrl->addrlen);
 179         if (err == -1) {
 180                 err(uctrl->udev, "error sending message: %m\n");
 181         }
 182         return err;
 183 }
 184
 185 int udev_ctrl_send_set_log_level(struct udev_ctrl *uctrl, int priority)
 186 {
 187         return ctrl_send(uctrl, UDEV_CTRL_SET_LOG_LEVEL, priority, NULL);
 188 }
 189
 190 int udev_ctrl_send_stop_exec_queue(struct udev_ctrl *uctrl)
 191 {
 192         return ctrl_send(uctrl, UDEV_CTRL_STOP_EXEC_QUEUE, 0, NULL);
 193 }
 194
 195 int udev_ctrl_send_start_exec_queue(struct udev_ctrl *uctrl)
 196 {
 197         return ctrl_send(uctrl, UDEV_CTRL_START_EXEC_QUEUE, 0, NULL);
 198 }
 199
 200 int udev_ctrl_send_reload_rules(struct udev_ctrl *uctrl)
 201 {
 202         return ctrl_send(uctrl, UDEV_CTRL_RELOAD_RULES, 0, NULL);
 203 }
 204
 205 int udev_ctrl_send_set_env(struct udev_ctrl *uctrl, const char *key)
 206 {
 207         return ctrl_send(uctrl, UDEV_CTRL_SET_ENV, 0, key);
 208 }
 209
 210 int udev_ctrl_send_set_children_max(struct udev_ctrl *uctrl, int count)
 211 {
 212         return ctrl_send(uctrl, UDEV_CTRL_SET_CHILDREN_MAX, count, NULL);
 213 }
 214
 215 int udev_ctrl_send_settle(struct udev_ctrl *uctrl)
 216 {
 217         return ctrl_send(uctrl, UDEV_CTRL_SETTLE, 0, NULL);
 218 }
 219
 220 struct udev_ctrl_msg *udev_ctrl_receive_msg(struct udev_ctrl *uctrl)
 221 {
 222         struct udev_ctrl_msg *uctrl_msg;
 223         ssize_t size;
 224         struct msghdr smsg;
 225         struct cmsghdr *cmsg;
 226         struct iovec iov;
 227         struct ucred *cred;
 228         char cred_msg[CMSG_SPACE(sizeof(struct ucred))];
 229
 230         uctrl_msg = calloc(1, sizeof(struct udev_ctrl_msg));
 231         if (uctrl_msg == NULL)
 232                 return NULL;
 233         uctrl_msg->refcount = 1;
 234         uctrl_msg->uctrl = uctrl;
 235
 236         iov.iov_base = &uctrl_msg->ctrl_msg_wire;
 237         iov.iov_len = sizeof(struct udev_ctrl_msg_wire);
 238
 239         memset(&smsg, 0x00, sizeof(struct msghdr));
 240         smsg.msg_iov = &iov;
 241         smsg.msg_iovlen = 1;
 242         smsg.msg_control = cred_msg;
 243         smsg.msg_controllen = sizeof(cred_msg);
 244
 245         size = recvmsg(uctrl->sock, &smsg, 0);
 246         if (size <  0) {
 247                 err(uctrl->udev, "unable to receive user udevd message: %m\n");
 248                 goto err;
 249         }
 250         cmsg = CMSG_FIRSTHDR(&smsg);
 251         cred = (struct ucred *) CMSG_DATA(cmsg);
 252
 253         if (cmsg == NULL || cmsg->cmsg_type != SCM_CREDENTIALS) {
 254                 err(uctrl->udev, "no sender credentials received, message ignored\n");
 255                 goto err;
 256         }
 257
 258         if (cred->uid != 0) {
 259                 err(uctrl->udev, "sender uid=%i, message ignored\n", cred->uid);
 260                 goto err;
 261         }
 262
 263         uctrl_msg->pid = cred->pid;
 264
 265         if (uctrl_msg->ctrl_msg_wire.magic != UDEV_CTRL_MAGIC) {
 266                 err(uctrl->udev, "message magic 0x%08x doesn't match, ignore it\n", uctrl_msg->ctrl_msg_wire.magic);
 267                 goto err;
 268         }
 269
 270         dbg(uctrl->udev, "created ctrl_msg %p (%i)\n", uctrl_msg, uctrl_msg->ctrl_msg_wire.type);
 271         return uctrl_msg;
 272 err:
 273         udev_ctrl_msg_unref(uctrl_msg);
 274         return NULL;
 275 }
 276
 277 struct udev_ctrl_msg *udev_ctrl_msg_ref(struct udev_ctrl_msg *ctrl_msg)
 278 {
 279         if (ctrl_msg == NULL)
 280                 return NULL;
 281         ctrl_msg->refcount++;
 282         return ctrl_msg;
 283 }
 284
 285 void udev_ctrl_msg_unref(struct udev_ctrl_msg *ctrl_msg)
 286 {
 287         if (ctrl_msg == NULL)
 288                 return;
 289         ctrl_msg->refcount--;
 290         if (ctrl_msg->refcount > 0)
 291                 return;
 292         dbg(ctrl_msg->uctrl->udev, "release ctrl_msg %p\n", ctrl_msg);
 293         free(ctrl_msg);
 294 }
 295
 296 int udev_ctrl_get_set_log_level(struct udev_ctrl_msg *ctrl_msg)
 297 {
 298         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_SET_LOG_LEVEL)
 299                 return ctrl_msg->ctrl_msg_wire.intval;
 300         return -1;
 301 }
 302
 303 int udev_ctrl_get_stop_exec_queue(struct udev_ctrl_msg *ctrl_msg)
 304 {
 305         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_STOP_EXEC_QUEUE)
 306                 return 1;
 307         return -1;
 308 }
 309
 310 int udev_ctrl_get_start_exec_queue(struct udev_ctrl_msg *ctrl_msg)
 311 {
 312         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_START_EXEC_QUEUE)
 313                 return 1;
 314         return -1;
 315 }
 316
 317 int udev_ctrl_get_reload_rules(struct udev_ctrl_msg *ctrl_msg)
 318 {
 319         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_RELOAD_RULES)
 320                 return 1;
 321         return -1;
 322 }
 323
 324 const char *udev_ctrl_get_set_env(struct udev_ctrl_msg *ctrl_msg)
 325 {
 326         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_SET_ENV)
 327                 return ctrl_msg->ctrl_msg_wire.buf;
 328         return NULL;
 329 }
 330
 331 int udev_ctrl_get_set_children_max(struct udev_ctrl_msg *ctrl_msg)
 332 {
 333         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_SET_CHILDREN_MAX)
 334                 return ctrl_msg->ctrl_msg_wire.intval;
 335         return -1;
 336 }
 337
 338 pid_t udev_ctrl_get_settle(struct udev_ctrl_msg *ctrl_msg)
 339 {
 340         if (ctrl_msg->ctrl_msg_wire.type == UDEV_CTRL_SETTLE)
 341                 return ctrl_msg->pid;
 342         return -1;
 343 }