1 /* 2 * kernel userspace event delivery 3 * 4 * Copyright (C) 2004 Red Hat, Inc. All rights reserved. 5 * Copyright (C) 2004 Novell, Inc. All rights reserved. 6 * Copyright (C) 2004 IBM, Inc. All rights reserved. 7 * 8 * Licensed under the GNU GPL v2. 9 * 10 * Authors: 11 * Robert Love <rml@novell.com> 12 * Kay Sievers <kay.sievers@vrfy.org> 13 * Arjan van de Ven <arjanv@redhat.com> 14 * Greg Kroah-Hartman <greg@kroah.com> 15 */ 16 17 #include <linux/spinlock.h> 18 #include <linux/string.h> 19 #include <linux/kobject.h> 20 #include <linux/module.h> 21 #include <linux/slab.h> 22 23 #include <linux/socket.h> 24 #include <linux/skbuff.h> 25 #include <linux/netlink.h> 26 #include <net/sock.h> 27 28 29 u64 uevent_seqnum; 30 char uevent_helper[UEVENT_HELPER_PATH_LEN] = CONFIG_UEVENT_HELPER_PATH; 31 static DEFINE_SPINLOCK(sequence_lock); 32 #if defined(CONFIG_NET) 33 static struct sock *uevent_sock; 34 #endif 35 36 /* the strings here must match the enum in include/linux/kobject.h */ 37 static const char *kobject_actions[] = { 38 [KOBJ_ADD] = "add", 39 [KOBJ_REMOVE] = "remove", 40 [KOBJ_CHANGE] = "change", 41 [KOBJ_MOVE] = "move", 42 [KOBJ_ONLINE] = "online", 43 [KOBJ_OFFLINE] = "offline", 44 }; 45 46 /** 47 * kobject_action_type - translate action string to numeric type 48 * 49 * @buf: buffer containing the action string, newline is ignored 50 * @len: length of buffer 51 * @type: pointer to the location to store the action type 52 * 53 * Returns 0 if the action string was recognized. 54 */ 55 int kobject_action_type(const char *buf, size_t count, 56 enum kobject_action *type) 57 { 58 enum kobject_action action; 59 int ret = -EINVAL; 60 61 if (count && (buf[count-1] == '\n' || buf[count-1] == '\0')) 62 count--; 63 64 if (!count) 65 goto out; 66 67 for (action = 0; action < ARRAY_SIZE(kobject_actions); action++) { 68 if (strncmp(kobject_actions[action], buf, count) != 0) 69 continue; 70 if (kobject_actions[action][count] != '\0') 71 continue; 72 *type = action; 73 ret = 0; 74 break; 75 } 76 out: 77 return ret; 78 } 79 80 /** 81 * kobject_uevent_env - send an uevent with environmental data 82 * 83 * @action: action that is happening 84 * @kobj: struct kobject that the action is happening to 85 * @envp_ext: pointer to environmental data 86 * 87 * Returns 0 if kobject_uevent() is completed with success or the 88 * corresponding error when it fails. 89 */ 90 int kobject_uevent_env(struct kobject *kobj, enum kobject_action action, 91 char *envp_ext[]) 92 { 93 struct kobj_uevent_env *env; 94 const char *action_string = kobject_actions[action]; 95 const char *devpath = NULL; 96 const char *subsystem; 97 struct kobject *top_kobj; 98 struct kset *kset; 99 const struct kset_uevent_ops *uevent_ops; 100 u64 seq; 101 int i = 0; 102 int retval = 0; 103 104 pr_debug("kobject: '%s' (%p): %s\n", 105 kobject_name(kobj), kobj, __func__); 106 107 /* search the kset we belong to */ 108 top_kobj = kobj; 109 while (!top_kobj->kset && top_kobj->parent) 110 top_kobj = top_kobj->parent; 111 112 if (!top_kobj->kset) { 113 pr_debug("kobject: '%s' (%p): %s: attempted to send uevent " 114 "without kset!\n", kobject_name(kobj), kobj, 115 __func__); 116 return -EINVAL; 117 } 118 119 kset = top_kobj->kset; 120 uevent_ops = kset->uevent_ops; 121 122 /* skip the event, if uevent_suppress is set*/ 123 if (kobj->uevent_suppress) { 124 pr_debug("kobject: '%s' (%p): %s: uevent_suppress " 125 "caused the event to drop!\n", 126 kobject_name(kobj), kobj, __func__); 127 return 0; 128 } 129 /* skip the event, if the filter returns zero. */ 130 if (uevent_ops && uevent_ops->filter) 131 if (!uevent_ops->filter(kset, kobj)) { 132 pr_debug("kobject: '%s' (%p): %s: filter function " 133 "caused the event to drop!\n", 134 kobject_name(kobj), kobj, __func__); 135 return 0; 136 } 137 138 /* originating subsystem */ 139 if (uevent_ops && uevent_ops->name) 140 subsystem = uevent_ops->name(kset, kobj); 141 else 142 subsystem = kobject_name(&kset->kobj); 143 if (!subsystem) { 144 pr_debug("kobject: '%s' (%p): %s: unset subsystem caused the " 145 "event to drop!\n", kobject_name(kobj), kobj, 146 __func__); 147 return 0; 148 } 149 150 /* environment buffer */ 151 env = kzalloc(sizeof(struct kobj_uevent_env), GFP_KERNEL); 152 if (!env) 153 return -ENOMEM; 154 155 /* complete object path */ 156 devpath = kobject_get_path(kobj, GFP_KERNEL); 157 if (!devpath) { 158 retval = -ENOENT; 159 goto exit; 160 } 161 162 /* default keys */ 163 retval = add_uevent_var(env, "ACTION=%s", action_string); 164 if (retval) 165 goto exit; 166 retval = add_uevent_var(env, "DEVPATH=%s", devpath); 167 if (retval) 168 goto exit; 169 retval = add_uevent_var(env, "SUBSYSTEM=%s", subsystem); 170 if (retval) 171 goto exit; 172 173 /* keys passed in from the caller */ 174 if (envp_ext) { 175 for (i = 0; envp_ext[i]; i++) { 176 retval = add_uevent_var(env, "%s", envp_ext[i]); 177 if (retval) 178 goto exit; 179 } 180 } 181 182 /* let the kset specific function add its stuff */ 183 if (uevent_ops && uevent_ops->uevent) { 184 retval = uevent_ops->uevent(kset, kobj, env); 185 if (retval) { 186 pr_debug("kobject: '%s' (%p): %s: uevent() returned " 187 "%d\n", kobject_name(kobj), kobj, 188 __func__, retval); 189 goto exit; 190 } 191 } 192 193 /* 194 * Mark "add" and "remove" events in the object to ensure proper 195 * events to userspace during automatic cleanup. If the object did 196 * send an "add" event, "remove" will automatically generated by 197 * the core, if not already done by the caller. 198 */ 199 if (action == KOBJ_ADD) 200 kobj->state_add_uevent_sent = 1; 201 else if (action == KOBJ_REMOVE) 202 kobj->state_remove_uevent_sent = 1; 203 204 /* we will send an event, so request a new sequence number */ 205 spin_lock(&sequence_lock); 206 seq = ++uevent_seqnum; 207 spin_unlock(&sequence_lock); 208 retval = add_uevent_var(env, "SEQNUM=%llu", (unsigned long long)seq); 209 if (retval) 210 goto exit; 211 212 #if defined(CONFIG_NET) 213 /* send netlink message */ 214 if (uevent_sock) { 215 struct sk_buff *skb; 216 size_t len; 217 218 /* allocate message with the maximum possible size */ 219 len = strlen(action_string) + strlen(devpath) + 2; 220 skb = alloc_skb(len + env->buflen, GFP_KERNEL); 221 if (skb) { 222 char *scratch; 223 224 /* add header */ 225 scratch = skb_put(skb, len); 226 sprintf(scratch, "%s@%s", action_string, devpath); 227 228 /* copy keys to our continuous event payload buffer */ 229 for (i = 0; i < env->envp_idx; i++) { 230 len = strlen(env->envp[i]) + 1; 231 scratch = skb_put(skb, len); 232 strcpy(scratch, env->envp[i]); 233 } 234 235 NETLINK_CB(skb).dst_group = 1; 236 retval = netlink_broadcast(uevent_sock, skb, 0, 1, 237 GFP_KERNEL); 238 /* ENOBUFS should be handled in userspace */ 239 if (retval == -ENOBUFS) 240 retval = 0; 241 } else 242 retval = -ENOMEM; 243 } 244 #endif 245 246 /* call uevent_helper, usually only enabled during early boot */ 247 if (uevent_helper[0]) { 248 char *argv [3]; 249 250 argv [0] = uevent_helper; 251 argv [1] = (char *)subsystem; 252 argv [2] = NULL; 253 retval = add_uevent_var(env, "HOME=/"); 254 if (retval) 255 goto exit; 256 retval = add_uevent_var(env, 257 "PATH=/sbin:/bin:/usr/sbin:/usr/bin"); 258 if (retval) 259 goto exit; 260 261 retval = call_usermodehelper(argv[0], argv, 262 env->envp, UMH_WAIT_EXEC); 263 } 264 265 exit: 266 kfree(devpath); 267 kfree(env); 268 return retval; 269 } 270 EXPORT_SYMBOL_GPL(kobject_uevent_env); 271 272 /** 273 * kobject_uevent - notify userspace by ending an uevent 274 * 275 * @action: action that is happening 276 * @kobj: struct kobject that the action is happening to 277 * 278 * Returns 0 if kobject_uevent() is completed with success or the 279 * corresponding error when it fails. 280 */ 281 int kobject_uevent(struct kobject *kobj, enum kobject_action action) 282 { 283 return kobject_uevent_env(kobj, action, NULL); 284 } 285 EXPORT_SYMBOL_GPL(kobject_uevent); 286 287 /** 288 * add_uevent_var - add key value string to the environment buffer 289 * @env: environment buffer structure 290 * @format: printf format for the key=value pair 291 * 292 * Returns 0 if environment variable was added successfully or -ENOMEM 293 * if no space was available. 294 */ 295 int add_uevent_var(struct kobj_uevent_env *env, const char *format, ...) 296 { 297 va_list args; 298 int len; 299 300 if (env->envp_idx >= ARRAY_SIZE(env->envp)) { 301 WARN(1, KERN_ERR "add_uevent_var: too many keys\n"); 302 return -ENOMEM; 303 } 304 305 va_start(args, format); 306 len = vsnprintf(&env->buf[env->buflen], 307 sizeof(env->buf) - env->buflen, 308 format, args); 309 va_end(args); 310 311 if (len >= (sizeof(env->buf) - env->buflen)) { 312 WARN(1, KERN_ERR "add_uevent_var: buffer size too small\n"); 313 return -ENOMEM; 314 } 315 316 env->envp[env->envp_idx++] = &env->buf[env->buflen]; 317 env->buflen += len + 1; 318 return 0; 319 } 320 EXPORT_SYMBOL_GPL(add_uevent_var); 321 322 #if defined(CONFIG_NET) 323 static int __init kobject_uevent_init(void) 324 { 325 uevent_sock = netlink_kernel_create(&init_net, NETLINK_KOBJECT_UEVENT, 326 1, NULL, NULL, THIS_MODULE); 327 if (!uevent_sock) { 328 printk(KERN_ERR 329 "kobject_uevent: unable to create netlink socket!\n"); 330 return -ENODEV; 331 } 332 netlink_set_nonroot(NETLINK_KOBJECT_UEVENT, NL_NONROOT_RECV); 333 return 0; 334 } 335 336 postcore_initcall(kobject_uevent_init); 337 #endif 338