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_uevent.h> 23 #include <linux/kobject.h> 24 #include <net/sock.h> 25 26 #define BUFFER_SIZE 1024 /* buffer for the hotplug env */ 27 #define NUM_ENVP 32 /* number of env pointers */ 28 29 #if defined(CONFIG_KOBJECT_UEVENT) || defined(CONFIG_HOTPLUG) 30 static char *action_to_string(enum kobject_action action) 31 { 32 switch (action) { 33 case KOBJ_ADD: 34 return "add"; 35 case KOBJ_REMOVE: 36 return "remove"; 37 case KOBJ_CHANGE: 38 return "change"; 39 case KOBJ_MOUNT: 40 return "mount"; 41 case KOBJ_UMOUNT: 42 return "umount"; 43 case KOBJ_OFFLINE: 44 return "offline"; 45 case KOBJ_ONLINE: 46 return "online"; 47 default: 48 return NULL; 49 } 50 } 51 #endif 52 53 #ifdef CONFIG_KOBJECT_UEVENT 54 static struct sock *uevent_sock; 55 56 /** 57 * send_uevent - notify userspace by sending event trough netlink socket 58 * 59 * @signal: signal name 60 * @obj: object path (kobject) 61 * @envp: possible hotplug environment to pass with the message 62 * @gfp_mask: 63 */ 64 static int send_uevent(const char *signal, const char *obj, 65 char **envp, int gfp_mask) 66 { 67 struct sk_buff *skb; 68 char *pos; 69 int len; 70 71 if (!uevent_sock) 72 return -EIO; 73 74 len = strlen(signal) + 1; 75 len += strlen(obj) + 1; 76 77 /* allocate buffer with the maximum possible message size */ 78 skb = alloc_skb(len + BUFFER_SIZE, gfp_mask); 79 if (!skb) 80 return -ENOMEM; 81 82 pos = skb_put(skb, len); 83 sprintf(pos, "%s@%s", signal, obj); 84 85 /* copy the environment key by key to our continuous buffer */ 86 if (envp) { 87 int i; 88 89 for (i = 2; envp[i]; i++) { 90 len = strlen(envp[i]) + 1; 91 pos = skb_put(skb, len); 92 strcpy(pos, envp[i]); 93 } 94 } 95 96 return netlink_broadcast(uevent_sock, skb, 0, 1, gfp_mask); 97 } 98 99 static int do_kobject_uevent(struct kobject *kobj, enum kobject_action action, 100 struct attribute *attr, int gfp_mask) 101 { 102 char *path; 103 char *attrpath; 104 char *signal; 105 int len; 106 int rc = -ENOMEM; 107 108 path = kobject_get_path(kobj, gfp_mask); 109 if (!path) 110 return -ENOMEM; 111 112 signal = action_to_string(action); 113 if (!signal) 114 return -EINVAL; 115 116 if (attr) { 117 len = strlen(path); 118 len += strlen(attr->name) + 2; 119 attrpath = kmalloc(len, gfp_mask); 120 if (!attrpath) 121 goto exit; 122 sprintf(attrpath, "%s/%s", path, attr->name); 123 rc = send_uevent(signal, attrpath, NULL, gfp_mask); 124 kfree(attrpath); 125 } else 126 rc = send_uevent(signal, path, NULL, gfp_mask); 127 128 exit: 129 kfree(path); 130 return rc; 131 } 132 133 /** 134 * kobject_uevent - notify userspace by sending event through netlink socket 135 * 136 * @signal: signal name 137 * @kobj: struct kobject that the event is happening to 138 * @attr: optional struct attribute the event belongs to 139 */ 140 int kobject_uevent(struct kobject *kobj, enum kobject_action action, 141 struct attribute *attr) 142 { 143 return do_kobject_uevent(kobj, action, attr, GFP_KERNEL); 144 } 145 EXPORT_SYMBOL_GPL(kobject_uevent); 146 147 int kobject_uevent_atomic(struct kobject *kobj, enum kobject_action action, 148 struct attribute *attr) 149 { 150 return do_kobject_uevent(kobj, action, attr, GFP_ATOMIC); 151 } 152 EXPORT_SYMBOL_GPL(kobject_uevent_atomic); 153 154 static int __init kobject_uevent_init(void) 155 { 156 uevent_sock = netlink_kernel_create(NETLINK_KOBJECT_UEVENT, NULL); 157 158 if (!uevent_sock) { 159 printk(KERN_ERR 160 "kobject_uevent: unable to create netlink socket!\n"); 161 return -ENODEV; 162 } 163 164 return 0; 165 } 166 167 postcore_initcall(kobject_uevent_init); 168 169 #else 170 static inline int send_uevent(const char *signal, const char *obj, 171 char **envp, int gfp_mask) 172 { 173 return 0; 174 } 175 176 #endif /* CONFIG_KOBJECT_UEVENT */ 177 178 179 #ifdef CONFIG_HOTPLUG 180 char hotplug_path[HOTPLUG_PATH_LEN] = "/sbin/hotplug"; 181 u64 hotplug_seqnum; 182 static DEFINE_SPINLOCK(sequence_lock); 183 184 /** 185 * kobject_hotplug - notify userspace by executing /sbin/hotplug 186 * 187 * @action: action that is happening (usually "ADD" or "REMOVE") 188 * @kobj: struct kobject that the action is happening to 189 */ 190 void kobject_hotplug(struct kobject *kobj, enum kobject_action action) 191 { 192 char *argv [3]; 193 char **envp = NULL; 194 char *buffer = NULL; 195 char *seq_buff; 196 char *scratch; 197 int i = 0; 198 int retval; 199 char *kobj_path = NULL; 200 char *name = NULL; 201 char *action_string; 202 u64 seq; 203 struct kobject *top_kobj = kobj; 204 struct kset *kset; 205 static struct kset_hotplug_ops null_hotplug_ops; 206 struct kset_hotplug_ops *hotplug_ops = &null_hotplug_ops; 207 208 /* If this kobj does not belong to a kset, 209 try to find a parent that does. */ 210 if (!top_kobj->kset && top_kobj->parent) { 211 do { 212 top_kobj = top_kobj->parent; 213 } while (!top_kobj->kset && top_kobj->parent); 214 } 215 216 if (top_kobj->kset) 217 kset = top_kobj->kset; 218 else 219 return; 220 221 if (kset->hotplug_ops) 222 hotplug_ops = kset->hotplug_ops; 223 224 /* If the kset has a filter operation, call it. 225 Skip the event, if the filter returns zero. */ 226 if (hotplug_ops->filter) { 227 if (!hotplug_ops->filter(kset, kobj)) 228 return; 229 } 230 231 pr_debug ("%s\n", __FUNCTION__); 232 233 action_string = action_to_string(action); 234 if (!action_string) 235 return; 236 237 envp = kmalloc(NUM_ENVP * sizeof (char *), GFP_KERNEL); 238 if (!envp) 239 return; 240 memset (envp, 0x00, NUM_ENVP * sizeof (char *)); 241 242 buffer = kmalloc(BUFFER_SIZE, GFP_KERNEL); 243 if (!buffer) 244 goto exit; 245 246 if (hotplug_ops->name) 247 name = hotplug_ops->name(kset, kobj); 248 if (name == NULL) 249 name = kset->kobj.name; 250 251 argv [0] = hotplug_path; 252 argv [1] = name; 253 argv [2] = NULL; 254 255 /* minimal command environment */ 256 envp [i++] = "HOME=/"; 257 envp [i++] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin"; 258 259 scratch = buffer; 260 261 envp [i++] = scratch; 262 scratch += sprintf(scratch, "ACTION=%s", action_string) + 1; 263 264 kobj_path = kobject_get_path(kobj, GFP_KERNEL); 265 if (!kobj_path) 266 goto exit; 267 268 envp [i++] = scratch; 269 scratch += sprintf (scratch, "DEVPATH=%s", kobj_path) + 1; 270 271 envp [i++] = scratch; 272 scratch += sprintf(scratch, "SUBSYSTEM=%s", name) + 1; 273 274 /* reserve space for the sequence, 275 * put the real one in after the hotplug call */ 276 envp[i++] = seq_buff = scratch; 277 scratch += strlen("SEQNUM=18446744073709551616") + 1; 278 279 if (hotplug_ops->hotplug) { 280 /* have the kset specific function add its stuff */ 281 retval = hotplug_ops->hotplug (kset, kobj, 282 &envp[i], NUM_ENVP - i, scratch, 283 BUFFER_SIZE - (scratch - buffer)); 284 if (retval) { 285 pr_debug ("%s - hotplug() returned %d\n", 286 __FUNCTION__, retval); 287 goto exit; 288 } 289 } 290 291 spin_lock(&sequence_lock); 292 seq = ++hotplug_seqnum; 293 spin_unlock(&sequence_lock); 294 sprintf(seq_buff, "SEQNUM=%llu", (unsigned long long)seq); 295 296 pr_debug ("%s: %s %s seq=%llu %s %s %s %s %s\n", 297 __FUNCTION__, argv[0], argv[1], (unsigned long long)seq, 298 envp[0], envp[1], envp[2], envp[3], envp[4]); 299 300 send_uevent(action_string, kobj_path, envp, GFP_KERNEL); 301 302 if (!hotplug_path[0]) 303 goto exit; 304 305 retval = call_usermodehelper (argv[0], argv, envp, 0); 306 if (retval) 307 pr_debug ("%s - call_usermodehelper returned %d\n", 308 __FUNCTION__, retval); 309 310 exit: 311 kfree(kobj_path); 312 kfree(buffer); 313 kfree(envp); 314 return; 315 } 316 EXPORT_SYMBOL(kobject_hotplug); 317 318 /** 319 * add_hotplug_env_var - helper for creating hotplug environment variables 320 * @envp: Pointer to table of environment variables, as passed into 321 * hotplug() method. 322 * @num_envp: Number of environment variable slots available, as 323 * passed into hotplug() method. 324 * @cur_index: Pointer to current index into @envp. It should be 325 * initialized to 0 before the first call to add_hotplug_env_var(), 326 * and will be incremented on success. 327 * @buffer: Pointer to buffer for environment variables, as passed 328 * into hotplug() method. 329 * @buffer_size: Length of @buffer, as passed into hotplug() method. 330 * @cur_len: Pointer to current length of space used in @buffer. 331 * Should be initialized to 0 before the first call to 332 * add_hotplug_env_var(), and will be incremented on success. 333 * @format: Format for creating environment variable (of the form 334 * "XXX=%x") for snprintf(). 335 * 336 * Returns 0 if environment variable was added successfully or -ENOMEM 337 * if no space was available. 338 */ 339 int add_hotplug_env_var(char **envp, int num_envp, int *cur_index, 340 char *buffer, int buffer_size, int *cur_len, 341 const char *format, ...) 342 { 343 va_list args; 344 345 /* 346 * We check against num_envp - 1 to make sure there is at 347 * least one slot left after we return, since the hotplug 348 * method needs to set the last slot to NULL. 349 */ 350 if (*cur_index >= num_envp - 1) 351 return -ENOMEM; 352 353 envp[*cur_index] = buffer + *cur_len; 354 355 va_start(args, format); 356 *cur_len += vsnprintf(envp[*cur_index], 357 max(buffer_size - *cur_len, 0), 358 format, args) + 1; 359 va_end(args); 360 361 if (*cur_len > buffer_size) 362 return -ENOMEM; 363 364 (*cur_index)++; 365 return 0; 366 } 367 EXPORT_SYMBOL(add_hotplug_env_var); 368 369 #endif /* CONFIG_HOTPLUG */ 370