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') 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("%s\n", __FUNCTION__); 102 103 /* search the kset we belong to */ 104 top_kobj = kobj; 105 while (!top_kobj->kset && top_kobj->parent) 106 top_kobj = top_kobj->parent; 107 108 if (!top_kobj->kset) { 109 pr_debug("kobject attempted to send uevent without kset!\n"); 110 return -EINVAL; 111 } 112 113 kset = top_kobj->kset; 114 uevent_ops = kset->uevent_ops; 115 116 /* skip the event, if the filter returns zero. */ 117 if (uevent_ops && uevent_ops->filter) 118 if (!uevent_ops->filter(kset, kobj)) { 119 pr_debug("kobject filter function caused the event to drop!\n"); 120 return 0; 121 } 122 123 /* originating subsystem */ 124 if (uevent_ops && uevent_ops->name) 125 subsystem = uevent_ops->name(kset, kobj); 126 else 127 subsystem = kobject_name(&kset->kobj); 128 if (!subsystem) { 129 pr_debug("unset subsytem caused the event to drop!\n"); 130 return 0; 131 } 132 133 /* environment buffer */ 134 env = kzalloc(sizeof(struct kobj_uevent_env), GFP_KERNEL); 135 if (!env) 136 return -ENOMEM; 137 138 /* complete object path */ 139 devpath = kobject_get_path(kobj, GFP_KERNEL); 140 if (!devpath) { 141 retval = -ENOENT; 142 goto exit; 143 } 144 145 /* default keys */ 146 retval = add_uevent_var(env, "ACTION=%s", action_string); 147 if (retval) 148 goto exit; 149 retval = add_uevent_var(env, "DEVPATH=%s", devpath); 150 if (retval) 151 goto exit; 152 retval = add_uevent_var(env, "SUBSYSTEM=%s", subsystem); 153 if (retval) 154 goto exit; 155 156 /* keys passed in from the caller */ 157 if (envp_ext) { 158 for (i = 0; envp_ext[i]; i++) { 159 retval = add_uevent_var(env, envp_ext[i]); 160 if (retval) 161 goto exit; 162 } 163 } 164 165 /* let the kset specific function add its stuff */ 166 if (uevent_ops && uevent_ops->uevent) { 167 retval = uevent_ops->uevent(kset, kobj, env); 168 if (retval) { 169 pr_debug ("%s - uevent() returned %d\n", 170 __FUNCTION__, retval); 171 goto exit; 172 } 173 } 174 175 /* we will send an event, so request a new sequence number */ 176 spin_lock(&sequence_lock); 177 seq = ++uevent_seqnum; 178 spin_unlock(&sequence_lock); 179 retval = add_uevent_var(env, "SEQNUM=%llu", (unsigned long long)seq); 180 if (retval) 181 goto exit; 182 183 #if defined(CONFIG_NET) 184 /* send netlink message */ 185 if (uevent_sock) { 186 struct sk_buff *skb; 187 size_t len; 188 189 /* allocate message with the maximum possible size */ 190 len = strlen(action_string) + strlen(devpath) + 2; 191 skb = alloc_skb(len + env->buflen, GFP_KERNEL); 192 if (skb) { 193 char *scratch; 194 195 /* add header */ 196 scratch = skb_put(skb, len); 197 sprintf(scratch, "%s@%s", action_string, devpath); 198 199 /* copy keys to our continuous event payload buffer */ 200 for (i = 0; i < env->envp_idx; i++) { 201 len = strlen(env->envp[i]) + 1; 202 scratch = skb_put(skb, len); 203 strcpy(scratch, env->envp[i]); 204 } 205 206 NETLINK_CB(skb).dst_group = 1; 207 netlink_broadcast(uevent_sock, skb, 0, 1, GFP_KERNEL); 208 } 209 } 210 #endif 211 212 /* call uevent_helper, usually only enabled during early boot */ 213 if (uevent_helper[0]) { 214 char *argv [3]; 215 216 argv [0] = uevent_helper; 217 argv [1] = (char *)subsystem; 218 argv [2] = NULL; 219 retval = add_uevent_var(env, "HOME=/"); 220 if (retval) 221 goto exit; 222 retval = add_uevent_var(env, "PATH=/sbin:/bin:/usr/sbin:/usr/bin"); 223 if (retval) 224 goto exit; 225 226 call_usermodehelper (argv[0], argv, env->envp, UMH_WAIT_EXEC); 227 } 228 229 exit: 230 kfree(devpath); 231 kfree(env); 232 return retval; 233 } 234 235 EXPORT_SYMBOL_GPL(kobject_uevent_env); 236 237 /** 238 * kobject_uevent - notify userspace by ending an uevent 239 * 240 * @action: action that is happening 241 * @kobj: struct kobject that the action is happening to 242 * 243 * Returns 0 if kobject_uevent() is completed with success or the 244 * corresponding error when it fails. 245 */ 246 int kobject_uevent(struct kobject *kobj, enum kobject_action action) 247 { 248 return kobject_uevent_env(kobj, action, NULL); 249 } 250 251 EXPORT_SYMBOL_GPL(kobject_uevent); 252 253 /** 254 * add_uevent_var - add key value string to the environment buffer 255 * @env: environment buffer structure 256 * @format: printf format for the key=value pair 257 * 258 * Returns 0 if environment variable was added successfully or -ENOMEM 259 * if no space was available. 260 */ 261 int add_uevent_var(struct kobj_uevent_env *env, const char *format, ...) 262 { 263 va_list args; 264 int len; 265 266 if (env->envp_idx >= ARRAY_SIZE(env->envp)) { 267 printk(KERN_ERR "add_uevent_var: too many keys\n"); 268 WARN_ON(1); 269 return -ENOMEM; 270 } 271 272 va_start(args, format); 273 len = vsnprintf(&env->buf[env->buflen], 274 sizeof(env->buf) - env->buflen, 275 format, args); 276 va_end(args); 277 278 if (len >= (sizeof(env->buf) - env->buflen)) { 279 printk(KERN_ERR "add_uevent_var: buffer size too small\n"); 280 WARN_ON(1); 281 return -ENOMEM; 282 } 283 284 env->envp[env->envp_idx++] = &env->buf[env->buflen]; 285 env->buflen += len + 1; 286 return 0; 287 } 288 EXPORT_SYMBOL_GPL(add_uevent_var); 289 290 #if defined(CONFIG_NET) 291 static int __init kobject_uevent_init(void) 292 { 293 uevent_sock = netlink_kernel_create(&init_net, NETLINK_KOBJECT_UEVENT, 294 1, NULL, NULL, THIS_MODULE); 295 if (!uevent_sock) { 296 printk(KERN_ERR 297 "kobject_uevent: unable to create netlink socket!\n"); 298 return -ENODEV; 299 } 300 301 return 0; 302 } 303 304 postcore_initcall(kobject_uevent_init); 305 #endif 306