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