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