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 through 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, gfp_t 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 NETLINK_CB(skb).dst_group = 1; 97 return netlink_broadcast(uevent_sock, skb, 0, 1, gfp_mask); 98 } 99 100 static int do_kobject_uevent(struct kobject *kobj, enum kobject_action action, 101 struct attribute *attr, gfp_t gfp_mask) 102 { 103 char *path; 104 char *attrpath; 105 char *signal; 106 int len; 107 int rc = -ENOMEM; 108 109 path = kobject_get_path(kobj, gfp_mask); 110 if (!path) 111 return -ENOMEM; 112 113 signal = action_to_string(action); 114 if (!signal) 115 return -EINVAL; 116 117 if (attr) { 118 len = strlen(path); 119 len += strlen(attr->name) + 2; 120 attrpath = kmalloc(len, gfp_mask); 121 if (!attrpath) 122 goto exit; 123 sprintf(attrpath, "%s/%s", path, attr->name); 124 rc = send_uevent(signal, attrpath, NULL, gfp_mask); 125 kfree(attrpath); 126 } else 127 rc = send_uevent(signal, path, NULL, gfp_mask); 128 129 exit: 130 kfree(path); 131 return rc; 132 } 133 134 /** 135 * kobject_uevent - notify userspace by sending event through netlink socket 136 * 137 * @signal: signal name 138 * @kobj: struct kobject that the event is happening to 139 * @attr: optional struct attribute the event belongs to 140 */ 141 int kobject_uevent(struct kobject *kobj, enum kobject_action action, 142 struct attribute *attr) 143 { 144 return do_kobject_uevent(kobj, action, attr, GFP_KERNEL); 145 } 146 EXPORT_SYMBOL_GPL(kobject_uevent); 147 148 int kobject_uevent_atomic(struct kobject *kobj, enum kobject_action action, 149 struct attribute *attr) 150 { 151 return do_kobject_uevent(kobj, action, attr, GFP_ATOMIC); 152 } 153 EXPORT_SYMBOL_GPL(kobject_uevent_atomic); 154 155 static int __init kobject_uevent_init(void) 156 { 157 uevent_sock = netlink_kernel_create(NETLINK_KOBJECT_UEVENT, 1, NULL, 158 THIS_MODULE); 159 160 if (!uevent_sock) { 161 printk(KERN_ERR 162 "kobject_uevent: unable to create netlink socket!\n"); 163 return -ENODEV; 164 } 165 166 return 0; 167 } 168 169 postcore_initcall(kobject_uevent_init); 170 171 #else 172 static inline int send_uevent(const char *signal, const char *obj, 173 char **envp, int gfp_mask) 174 { 175 return 0; 176 } 177 178 #endif /* CONFIG_KOBJECT_UEVENT */ 179 180 181 #ifdef CONFIG_HOTPLUG 182 char hotplug_path[HOTPLUG_PATH_LEN] = "/sbin/hotplug"; 183 u64 hotplug_seqnum; 184 static DEFINE_SPINLOCK(sequence_lock); 185 186 /** 187 * kobject_hotplug - notify userspace by executing /sbin/hotplug 188 * 189 * @action: action that is happening (usually "ADD" or "REMOVE") 190 * @kobj: struct kobject that the action is happening to 191 */ 192 void kobject_hotplug(struct kobject *kobj, enum kobject_action action) 193 { 194 char *argv [3]; 195 char **envp = NULL; 196 char *buffer = NULL; 197 char *seq_buff; 198 char *scratch; 199 int i = 0; 200 int retval; 201 char *kobj_path = NULL; 202 const char *name = NULL; 203 char *action_string; 204 u64 seq; 205 struct kobject *top_kobj = kobj; 206 struct kset *kset; 207 static struct kset_hotplug_ops null_hotplug_ops; 208 struct kset_hotplug_ops *hotplug_ops = &null_hotplug_ops; 209 210 /* If this kobj does not belong to a kset, 211 try to find a parent that does. */ 212 if (!top_kobj->kset && top_kobj->parent) { 213 do { 214 top_kobj = top_kobj->parent; 215 } while (!top_kobj->kset && top_kobj->parent); 216 } 217 218 if (top_kobj->kset) 219 kset = top_kobj->kset; 220 else 221 return; 222 223 if (kset->hotplug_ops) 224 hotplug_ops = kset->hotplug_ops; 225 226 /* If the kset has a filter operation, call it. 227 Skip the event, if the filter returns zero. */ 228 if (hotplug_ops->filter) { 229 if (!hotplug_ops->filter(kset, kobj)) 230 return; 231 } 232 233 pr_debug ("%s\n", __FUNCTION__); 234 235 action_string = action_to_string(action); 236 if (!action_string) 237 return; 238 239 envp = kmalloc(NUM_ENVP * sizeof (char *), GFP_KERNEL); 240 if (!envp) 241 return; 242 memset (envp, 0x00, NUM_ENVP * sizeof (char *)); 243 244 buffer = kmalloc(BUFFER_SIZE, GFP_KERNEL); 245 if (!buffer) 246 goto exit; 247 248 if (hotplug_ops->name) 249 name = hotplug_ops->name(kset, kobj); 250 if (name == NULL) 251 name = kobject_name(&kset->kobj); 252 253 argv [0] = hotplug_path; 254 argv [1] = (char *)name; /* won't be changed but 'const' has to go */ 255 argv [2] = NULL; 256 257 /* minimal command environment */ 258 envp [i++] = "HOME=/"; 259 envp [i++] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin"; 260 261 scratch = buffer; 262 263 envp [i++] = scratch; 264 scratch += sprintf(scratch, "ACTION=%s", action_string) + 1; 265 266 kobj_path = kobject_get_path(kobj, GFP_KERNEL); 267 if (!kobj_path) 268 goto exit; 269 270 envp [i++] = scratch; 271 scratch += sprintf (scratch, "DEVPATH=%s", kobj_path) + 1; 272 273 envp [i++] = scratch; 274 scratch += sprintf(scratch, "SUBSYSTEM=%s", name) + 1; 275 276 /* reserve space for the sequence, 277 * put the real one in after the hotplug call */ 278 envp[i++] = seq_buff = scratch; 279 scratch += strlen("SEQNUM=18446744073709551616") + 1; 280 281 if (hotplug_ops->hotplug) { 282 /* have the kset specific function add its stuff */ 283 retval = hotplug_ops->hotplug (kset, kobj, 284 &envp[i], NUM_ENVP - i, scratch, 285 BUFFER_SIZE - (scratch - buffer)); 286 if (retval) { 287 pr_debug ("%s - hotplug() returned %d\n", 288 __FUNCTION__, retval); 289 goto exit; 290 } 291 } 292 293 spin_lock(&sequence_lock); 294 seq = ++hotplug_seqnum; 295 spin_unlock(&sequence_lock); 296 sprintf(seq_buff, "SEQNUM=%llu", (unsigned long long)seq); 297 298 pr_debug ("%s: %s %s seq=%llu %s %s %s %s %s\n", 299 __FUNCTION__, argv[0], argv[1], (unsigned long long)seq, 300 envp[0], envp[1], envp[2], envp[3], envp[4]); 301 302 send_uevent(action_string, kobj_path, envp, GFP_KERNEL); 303 304 if (!hotplug_path[0]) 305 goto exit; 306 307 retval = call_usermodehelper (argv[0], argv, envp, 0); 308 if (retval) 309 pr_debug ("%s - call_usermodehelper returned %d\n", 310 __FUNCTION__, retval); 311 312 exit: 313 kfree(kobj_path); 314 kfree(buffer); 315 kfree(envp); 316 return; 317 } 318 EXPORT_SYMBOL(kobject_hotplug); 319 320 /** 321 * add_hotplug_env_var - helper for creating hotplug environment variables 322 * @envp: Pointer to table of environment variables, as passed into 323 * hotplug() method. 324 * @num_envp: Number of environment variable slots available, as 325 * passed into hotplug() method. 326 * @cur_index: Pointer to current index into @envp. It should be 327 * initialized to 0 before the first call to add_hotplug_env_var(), 328 * and will be incremented on success. 329 * @buffer: Pointer to buffer for environment variables, as passed 330 * into hotplug() method. 331 * @buffer_size: Length of @buffer, as passed into hotplug() method. 332 * @cur_len: Pointer to current length of space used in @buffer. 333 * Should be initialized to 0 before the first call to 334 * add_hotplug_env_var(), and will be incremented on success. 335 * @format: Format for creating environment variable (of the form 336 * "XXX=%x") for snprintf(). 337 * 338 * Returns 0 if environment variable was added successfully or -ENOMEM 339 * if no space was available. 340 */ 341 int add_hotplug_env_var(char **envp, int num_envp, int *cur_index, 342 char *buffer, int buffer_size, int *cur_len, 343 const char *format, ...) 344 { 345 va_list args; 346 347 /* 348 * We check against num_envp - 1 to make sure there is at 349 * least one slot left after we return, since the hotplug 350 * method needs to set the last slot to NULL. 351 */ 352 if (*cur_index >= num_envp - 1) 353 return -ENOMEM; 354 355 envp[*cur_index] = buffer + *cur_len; 356 357 va_start(args, format); 358 *cur_len += vsnprintf(envp[*cur_index], 359 max(buffer_size - *cur_len, 0), 360 format, args) + 1; 361 va_end(args); 362 363 if (*cur_len > buffer_size) 364 return -ENOMEM; 365 366 (*cur_index)++; 367 return 0; 368 } 369 EXPORT_SYMBOL(add_hotplug_env_var); 370 371 #endif /* CONFIG_HOTPLUG */ 372