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 void kobject_uevent_env(struct kobject *kobj, enum kobject_action action, 68 char *envp_ext[]) 69 { 70 char **envp; 71 char *buffer; 72 char *scratch; 73 const char *action_string; 74 const char *devpath = NULL; 75 const char *subsystem; 76 struct kobject *top_kobj; 77 struct kset *kset; 78 struct kset_uevent_ops *uevent_ops; 79 u64 seq; 80 char *seq_buff; 81 int i = 0; 82 int retval; 83 int j; 84 85 pr_debug("%s\n", __FUNCTION__); 86 87 action_string = action_to_string(action); 88 if (!action_string) 89 return; 90 91 /* search the kset we belong to */ 92 top_kobj = kobj; 93 if (!top_kobj->kset && top_kobj->parent) { 94 do { 95 top_kobj = top_kobj->parent; 96 } while (!top_kobj->kset && top_kobj->parent); 97 } 98 if (!top_kobj->kset) 99 return; 100 101 kset = top_kobj->kset; 102 uevent_ops = kset->uevent_ops; 103 104 /* skip the event, if the filter returns zero. */ 105 if (uevent_ops && uevent_ops->filter) 106 if (!uevent_ops->filter(kset, kobj)) 107 return; 108 109 /* environment index */ 110 envp = kzalloc(NUM_ENVP * sizeof (char *), GFP_KERNEL); 111 if (!envp) 112 return; 113 114 /* environment values */ 115 buffer = kmalloc(BUFFER_SIZE, GFP_KERNEL); 116 if (!buffer) 117 goto exit; 118 119 /* complete object path */ 120 devpath = kobject_get_path(kobj, GFP_KERNEL); 121 if (!devpath) 122 goto exit; 123 124 /* originating subsystem */ 125 if (uevent_ops && uevent_ops->name) 126 subsystem = uevent_ops->name(kset, kobj); 127 else 128 subsystem = kobject_name(&kset->kobj); 129 130 /* event environemnt for helper process only */ 131 envp[i++] = "HOME=/"; 132 envp[i++] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin"; 133 134 /* default keys */ 135 scratch = buffer; 136 envp [i++] = scratch; 137 scratch += sprintf(scratch, "ACTION=%s", action_string) + 1; 138 envp [i++] = scratch; 139 scratch += sprintf (scratch, "DEVPATH=%s", devpath) + 1; 140 envp [i++] = scratch; 141 scratch += sprintf(scratch, "SUBSYSTEM=%s", subsystem) + 1; 142 for (j = 0; envp_ext && envp_ext[j]; j++) 143 envp[i++] = envp_ext[j]; 144 /* just reserve the space, overwrite it after kset call has returned */ 145 envp[i++] = seq_buff = scratch; 146 scratch += strlen("SEQNUM=18446744073709551616") + 1; 147 148 /* let the kset specific function add its stuff */ 149 if (uevent_ops && uevent_ops->uevent) { 150 retval = uevent_ops->uevent(kset, kobj, 151 &envp[i], NUM_ENVP - i, scratch, 152 BUFFER_SIZE - (scratch - buffer)); 153 if (retval) { 154 pr_debug ("%s - uevent() returned %d\n", 155 __FUNCTION__, retval); 156 goto exit; 157 } 158 } 159 160 /* we will send an event, request a new sequence number */ 161 spin_lock(&sequence_lock); 162 seq = ++uevent_seqnum; 163 spin_unlock(&sequence_lock); 164 sprintf(seq_buff, "SEQNUM=%llu", (unsigned long long)seq); 165 166 #if defined(CONFIG_NET) 167 /* send netlink message */ 168 if (uevent_sock) { 169 struct sk_buff *skb; 170 size_t len; 171 172 /* allocate message with the maximum possible size */ 173 len = strlen(action_string) + strlen(devpath) + 2; 174 skb = alloc_skb(len + BUFFER_SIZE, GFP_KERNEL); 175 if (skb) { 176 /* add header */ 177 scratch = skb_put(skb, len); 178 sprintf(scratch, "%s@%s", action_string, devpath); 179 180 /* copy keys to our continuous event payload buffer */ 181 for (i = 2; envp[i]; i++) { 182 len = strlen(envp[i]) + 1; 183 scratch = skb_put(skb, len); 184 strcpy(scratch, envp[i]); 185 } 186 187 NETLINK_CB(skb).dst_group = 1; 188 netlink_broadcast(uevent_sock, skb, 0, 1, GFP_KERNEL); 189 } 190 } 191 #endif 192 193 /* call uevent_helper, usually only enabled during early boot */ 194 if (uevent_helper[0]) { 195 char *argv [3]; 196 197 argv [0] = uevent_helper; 198 argv [1] = (char *)subsystem; 199 argv [2] = NULL; 200 call_usermodehelper (argv[0], argv, envp, 0); 201 } 202 203 exit: 204 kfree(devpath); 205 kfree(buffer); 206 kfree(envp); 207 return; 208 } 209 210 EXPORT_SYMBOL_GPL(kobject_uevent_env); 211 212 /** 213 * kobject_uevent - notify userspace by ending an uevent 214 * 215 * @action: action that is happening (usually KOBJ_ADD and KOBJ_REMOVE) 216 * @kobj: struct kobject that the action is happening to 217 */ 218 void kobject_uevent(struct kobject *kobj, enum kobject_action action) 219 { 220 kobject_uevent_env(kobj, action, NULL); 221 } 222 223 EXPORT_SYMBOL_GPL(kobject_uevent); 224 225 /** 226 * add_uevent_var - helper for creating event variables 227 * @envp: Pointer to table of environment variables, as passed into 228 * uevent() method. 229 * @num_envp: Number of environment variable slots available, as 230 * passed into uevent() method. 231 * @cur_index: Pointer to current index into @envp. It should be 232 * initialized to 0 before the first call to add_uevent_var(), 233 * and will be incremented on success. 234 * @buffer: Pointer to buffer for environment variables, as passed 235 * into uevent() method. 236 * @buffer_size: Length of @buffer, as passed into uevent() method. 237 * @cur_len: Pointer to current length of space used in @buffer. 238 * Should be initialized to 0 before the first call to 239 * add_uevent_var(), and will be incremented on success. 240 * @format: Format for creating environment variable (of the form 241 * "XXX=%x") for snprintf(). 242 * 243 * Returns 0 if environment variable was added successfully or -ENOMEM 244 * if no space was available. 245 */ 246 int add_uevent_var(char **envp, int num_envp, int *cur_index, 247 char *buffer, int buffer_size, int *cur_len, 248 const char *format, ...) 249 { 250 va_list args; 251 252 /* 253 * We check against num_envp - 1 to make sure there is at 254 * least one slot left after we return, since kobject_uevent() 255 * needs to set the last slot to NULL. 256 */ 257 if (*cur_index >= num_envp - 1) 258 return -ENOMEM; 259 260 envp[*cur_index] = buffer + *cur_len; 261 262 va_start(args, format); 263 *cur_len += vsnprintf(envp[*cur_index], 264 max(buffer_size - *cur_len, 0), 265 format, args) + 1; 266 va_end(args); 267 268 if (*cur_len > buffer_size) 269 return -ENOMEM; 270 271 (*cur_index)++; 272 return 0; 273 } 274 EXPORT_SYMBOL_GPL(add_uevent_var); 275 276 #if defined(CONFIG_NET) 277 static int __init kobject_uevent_init(void) 278 { 279 uevent_sock = netlink_kernel_create(NETLINK_KOBJECT_UEVENT, 1, NULL, 280 THIS_MODULE); 281 282 if (!uevent_sock) { 283 printk(KERN_ERR 284 "kobject_uevent: unable to create netlink socket!\n"); 285 return -ENODEV; 286 } 287 288 return 0; 289 } 290 291 postcore_initcall(kobject_uevent_init); 292 #endif 293 294 #endif /* CONFIG_HOTPLUG */ 295