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 #define BUFFER_SIZE 2048 /* buffer for the variables */ 26 #define NUM_ENVP 32 /* number of env pointers */ 27 28 #if defined(CONFIG_HOTPLUG) 29 u64 uevent_seqnum; 30 char uevent_helper[UEVENT_HELPER_PATH_LEN] = "/sbin/hotplug"; 31 static DEFINE_SPINLOCK(sequence_lock); 32 #if defined(CONFIG_NET) 33 static struct sock *uevent_sock; 34 #endif 35 36 static char *action_to_string(enum kobject_action action) 37 { 38 switch (action) { 39 case KOBJ_ADD: 40 return "add"; 41 case KOBJ_REMOVE: 42 return "remove"; 43 case KOBJ_CHANGE: 44 return "change"; 45 case KOBJ_MOUNT: 46 return "mount"; 47 case KOBJ_UMOUNT: 48 return "umount"; 49 case KOBJ_OFFLINE: 50 return "offline"; 51 case KOBJ_ONLINE: 52 return "online"; 53 case KOBJ_MOVE: 54 return "move"; 55 default: 56 return NULL; 57 } 58 } 59 60 /** 61 * kobject_uevent_env - send an uevent with environmental data 62 * 63 * @action: action that is happening (usually KOBJ_MOVE) 64 * @kobj: struct kobject that the action is happening to 65 * @envp_ext: pointer to environmental data 66 * 67 * Returns 0 if kobject_uevent() is completed with success or the 68 * corresponding error when it fails. 69 */ 70 int kobject_uevent_env(struct kobject *kobj, enum kobject_action action, 71 char *envp_ext[]) 72 { 73 char **envp; 74 char *buffer; 75 char *scratch; 76 const char *action_string; 77 const char *devpath = NULL; 78 const char *subsystem; 79 struct kobject *top_kobj; 80 struct kset *kset; 81 struct kset_uevent_ops *uevent_ops; 82 u64 seq; 83 char *seq_buff; 84 int i = 0; 85 int retval = 0; 86 int j; 87 88 pr_debug("%s\n", __FUNCTION__); 89 90 action_string = action_to_string(action); 91 if (!action_string) { 92 pr_debug("kobject attempted to send uevent without action_string!\n"); 93 return -EINVAL; 94 } 95 96 /* search the kset we belong to */ 97 top_kobj = kobj; 98 if (!top_kobj->kset && top_kobj->parent) { 99 do { 100 top_kobj = top_kobj->parent; 101 } while (!top_kobj->kset && top_kobj->parent); 102 } 103 if (!top_kobj->kset) { 104 pr_debug("kobject attempted to send uevent without kset!\n"); 105 return -EINVAL; 106 } 107 108 kset = top_kobj->kset; 109 uevent_ops = kset->uevent_ops; 110 111 /* skip the event, if the filter returns zero. */ 112 if (uevent_ops && uevent_ops->filter) 113 if (!uevent_ops->filter(kset, kobj)) { 114 pr_debug("kobject filter function caused the event to drop!\n"); 115 return 0; 116 } 117 118 /* environment index */ 119 envp = kzalloc(NUM_ENVP * sizeof (char *), GFP_KERNEL); 120 if (!envp) 121 return -ENOMEM; 122 123 /* environment values */ 124 buffer = kmalloc(BUFFER_SIZE, GFP_KERNEL); 125 if (!buffer) { 126 retval = -ENOMEM; 127 goto exit; 128 } 129 130 /* complete object path */ 131 devpath = kobject_get_path(kobj, GFP_KERNEL); 132 if (!devpath) { 133 retval = -ENOENT; 134 goto exit; 135 } 136 137 /* originating subsystem */ 138 if (uevent_ops && uevent_ops->name) 139 subsystem = uevent_ops->name(kset, kobj); 140 else 141 subsystem = kobject_name(&kset->kobj); 142 143 /* event environemnt for helper process only */ 144 envp[i++] = "HOME=/"; 145 envp[i++] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin"; 146 147 /* default keys */ 148 scratch = buffer; 149 envp [i++] = scratch; 150 scratch += sprintf(scratch, "ACTION=%s", action_string) + 1; 151 envp [i++] = scratch; 152 scratch += sprintf (scratch, "DEVPATH=%s", devpath) + 1; 153 envp [i++] = scratch; 154 scratch += sprintf(scratch, "SUBSYSTEM=%s", subsystem) + 1; 155 for (j = 0; envp_ext && envp_ext[j]; j++) 156 envp[i++] = envp_ext[j]; 157 /* just reserve the space, overwrite it after kset call has returned */ 158 envp[i++] = seq_buff = scratch; 159 scratch += strlen("SEQNUM=18446744073709551616") + 1; 160 161 /* let the kset specific function add its stuff */ 162 if (uevent_ops && uevent_ops->uevent) { 163 retval = uevent_ops->uevent(kset, kobj, 164 &envp[i], NUM_ENVP - i, scratch, 165 BUFFER_SIZE - (scratch - buffer)); 166 if (retval) { 167 pr_debug ("%s - uevent() returned %d\n", 168 __FUNCTION__, retval); 169 goto exit; 170 } 171 } 172 173 /* we will send an event, request a new sequence number */ 174 spin_lock(&sequence_lock); 175 seq = ++uevent_seqnum; 176 spin_unlock(&sequence_lock); 177 sprintf(seq_buff, "SEQNUM=%llu", (unsigned long long)seq); 178 179 #if defined(CONFIG_NET) 180 /* send netlink message */ 181 if (uevent_sock) { 182 struct sk_buff *skb; 183 size_t len; 184 185 /* allocate message with the maximum possible size */ 186 len = strlen(action_string) + strlen(devpath) + 2; 187 skb = alloc_skb(len + BUFFER_SIZE, GFP_KERNEL); 188 if (skb) { 189 /* add header */ 190 scratch = skb_put(skb, len); 191 sprintf(scratch, "%s@%s", action_string, devpath); 192 193 /* copy keys to our continuous event payload buffer */ 194 for (i = 2; envp[i]; i++) { 195 len = strlen(envp[i]) + 1; 196 scratch = skb_put(skb, len); 197 strcpy(scratch, envp[i]); 198 } 199 200 NETLINK_CB(skb).dst_group = 1; 201 netlink_broadcast(uevent_sock, skb, 0, 1, GFP_KERNEL); 202 } 203 } 204 #endif 205 206 /* call uevent_helper, usually only enabled during early boot */ 207 if (uevent_helper[0]) { 208 char *argv [3]; 209 210 argv [0] = uevent_helper; 211 argv [1] = (char *)subsystem; 212 argv [2] = NULL; 213 call_usermodehelper (argv[0], argv, envp, 0); 214 } 215 216 exit: 217 kfree(devpath); 218 kfree(buffer); 219 kfree(envp); 220 return retval; 221 } 222 223 EXPORT_SYMBOL_GPL(kobject_uevent_env); 224 225 /** 226 * kobject_uevent - notify userspace by ending an uevent 227 * 228 * @action: action that is happening (usually KOBJ_ADD and KOBJ_REMOVE) 229 * @kobj: struct kobject that the action is happening to 230 * 231 * Returns 0 if kobject_uevent() is completed with success or the 232 * corresponding error when it fails. 233 */ 234 int kobject_uevent(struct kobject *kobj, enum kobject_action action) 235 { 236 return kobject_uevent_env(kobj, action, NULL); 237 } 238 239 EXPORT_SYMBOL_GPL(kobject_uevent); 240 241 /** 242 * add_uevent_var - helper for creating event variables 243 * @envp: Pointer to table of environment variables, as passed into 244 * uevent() method. 245 * @num_envp: Number of environment variable slots available, as 246 * passed into uevent() method. 247 * @cur_index: Pointer to current index into @envp. It should be 248 * initialized to 0 before the first call to add_uevent_var(), 249 * and will be incremented on success. 250 * @buffer: Pointer to buffer for environment variables, as passed 251 * into uevent() method. 252 * @buffer_size: Length of @buffer, as passed into uevent() method. 253 * @cur_len: Pointer to current length of space used in @buffer. 254 * Should be initialized to 0 before the first call to 255 * add_uevent_var(), and will be incremented on success. 256 * @format: Format for creating environment variable (of the form 257 * "XXX=%x") for snprintf(). 258 * 259 * Returns 0 if environment variable was added successfully or -ENOMEM 260 * if no space was available. 261 */ 262 int add_uevent_var(char **envp, int num_envp, int *cur_index, 263 char *buffer, int buffer_size, int *cur_len, 264 const char *format, ...) 265 { 266 va_list args; 267 268 /* 269 * We check against num_envp - 1 to make sure there is at 270 * least one slot left after we return, since kobject_uevent() 271 * needs to set the last slot to NULL. 272 */ 273 if (*cur_index >= num_envp - 1) 274 return -ENOMEM; 275 276 envp[*cur_index] = buffer + *cur_len; 277 278 va_start(args, format); 279 *cur_len += vsnprintf(envp[*cur_index], 280 max(buffer_size - *cur_len, 0), 281 format, args) + 1; 282 va_end(args); 283 284 if (*cur_len > buffer_size) 285 return -ENOMEM; 286 287 (*cur_index)++; 288 return 0; 289 } 290 EXPORT_SYMBOL_GPL(add_uevent_var); 291 292 #if defined(CONFIG_NET) 293 static int __init kobject_uevent_init(void) 294 { 295 uevent_sock = netlink_kernel_create(NETLINK_KOBJECT_UEVENT, 1, NULL, 296 THIS_MODULE); 297 298 if (!uevent_sock) { 299 printk(KERN_ERR 300 "kobject_uevent: unable to create netlink socket!\n"); 301 return -ENODEV; 302 } 303 304 return 0; 305 } 306 307 postcore_initcall(kobject_uevent_init); 308 #endif 309 310 #endif /* CONFIG_HOTPLUG */ 311