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_DOCK: 54 return "dock"; 55 case KOBJ_UNDOCK: 56 return "undock"; 57 default: 58 return NULL; 59 } 60 } 61 62 /** 63 * kobject_uevent - notify userspace by ending an uevent 64 * 65 * @action: action that is happening (usually KOBJ_ADD and KOBJ_REMOVE) 66 * @kobj: struct kobject that the action is happening to 67 */ 68 void kobject_uevent(struct kobject *kobj, enum kobject_action action) 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 84 pr_debug("%s\n", __FUNCTION__); 85 86 action_string = action_to_string(action); 87 if (!action_string) 88 return; 89 90 /* search the kset we belong to */ 91 top_kobj = kobj; 92 if (!top_kobj->kset && top_kobj->parent) { 93 do { 94 top_kobj = top_kobj->parent; 95 } while (!top_kobj->kset && top_kobj->parent); 96 } 97 if (!top_kobj->kset) 98 return; 99 100 kset = top_kobj->kset; 101 uevent_ops = kset->uevent_ops; 102 103 /* skip the event, if the filter returns zero. */ 104 if (uevent_ops && uevent_ops->filter) 105 if (!uevent_ops->filter(kset, kobj)) 106 return; 107 108 /* environment index */ 109 envp = kzalloc(NUM_ENVP * sizeof (char *), GFP_KERNEL); 110 if (!envp) 111 return; 112 113 /* environment values */ 114 buffer = kmalloc(BUFFER_SIZE, GFP_KERNEL); 115 if (!buffer) 116 goto exit; 117 118 /* complete object path */ 119 devpath = kobject_get_path(kobj, GFP_KERNEL); 120 if (!devpath) 121 goto exit; 122 123 /* originating subsystem */ 124 if (uevent_ops && uevent_ops->name) 125 subsystem = uevent_ops->name(kset, kobj); 126 else 127 subsystem = kobject_name(&kset->kobj); 128 129 /* event environemnt for helper process only */ 130 envp[i++] = "HOME=/"; 131 envp[i++] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin"; 132 133 /* default keys */ 134 scratch = buffer; 135 envp [i++] = scratch; 136 scratch += sprintf(scratch, "ACTION=%s", action_string) + 1; 137 envp [i++] = scratch; 138 scratch += sprintf (scratch, "DEVPATH=%s", devpath) + 1; 139 envp [i++] = scratch; 140 scratch += sprintf(scratch, "SUBSYSTEM=%s", subsystem) + 1; 141 142 /* just reserve the space, overwrite it after kset call has returned */ 143 envp[i++] = seq_buff = scratch; 144 scratch += strlen("SEQNUM=18446744073709551616") + 1; 145 146 /* let the kset specific function add its stuff */ 147 if (uevent_ops && uevent_ops->uevent) { 148 retval = uevent_ops->uevent(kset, kobj, 149 &envp[i], NUM_ENVP - i, scratch, 150 BUFFER_SIZE - (scratch - buffer)); 151 if (retval) { 152 pr_debug ("%s - uevent() returned %d\n", 153 __FUNCTION__, retval); 154 goto exit; 155 } 156 } 157 158 /* we will send an event, request a new sequence number */ 159 spin_lock(&sequence_lock); 160 seq = ++uevent_seqnum; 161 spin_unlock(&sequence_lock); 162 sprintf(seq_buff, "SEQNUM=%llu", (unsigned long long)seq); 163 164 #if defined(CONFIG_NET) 165 /* send netlink message */ 166 if (uevent_sock) { 167 struct sk_buff *skb; 168 size_t len; 169 170 /* allocate message with the maximum possible size */ 171 len = strlen(action_string) + strlen(devpath) + 2; 172 skb = alloc_skb(len + BUFFER_SIZE, GFP_KERNEL); 173 if (skb) { 174 /* add header */ 175 scratch = skb_put(skb, len); 176 sprintf(scratch, "%s@%s", action_string, devpath); 177 178 /* copy keys to our continuous event payload buffer */ 179 for (i = 2; envp[i]; i++) { 180 len = strlen(envp[i]) + 1; 181 scratch = skb_put(skb, len); 182 strcpy(scratch, envp[i]); 183 } 184 185 NETLINK_CB(skb).dst_group = 1; 186 netlink_broadcast(uevent_sock, skb, 0, 1, GFP_KERNEL); 187 } 188 } 189 #endif 190 191 /* call uevent_helper, usually only enabled during early boot */ 192 if (uevent_helper[0]) { 193 char *argv [3]; 194 195 argv [0] = uevent_helper; 196 argv [1] = (char *)subsystem; 197 argv [2] = NULL; 198 call_usermodehelper (argv[0], argv, envp, 0); 199 } 200 201 exit: 202 kfree(devpath); 203 kfree(buffer); 204 kfree(envp); 205 return; 206 } 207 EXPORT_SYMBOL_GPL(kobject_uevent); 208 209 /** 210 * add_uevent_var - helper for creating event variables 211 * @envp: Pointer to table of environment variables, as passed into 212 * uevent() method. 213 * @num_envp: Number of environment variable slots available, as 214 * passed into uevent() method. 215 * @cur_index: Pointer to current index into @envp. It should be 216 * initialized to 0 before the first call to add_uevent_var(), 217 * and will be incremented on success. 218 * @buffer: Pointer to buffer for environment variables, as passed 219 * into uevent() method. 220 * @buffer_size: Length of @buffer, as passed into uevent() method. 221 * @cur_len: Pointer to current length of space used in @buffer. 222 * Should be initialized to 0 before the first call to 223 * add_uevent_var(), and will be incremented on success. 224 * @format: Format for creating environment variable (of the form 225 * "XXX=%x") for snprintf(). 226 * 227 * Returns 0 if environment variable was added successfully or -ENOMEM 228 * if no space was available. 229 */ 230 int add_uevent_var(char **envp, int num_envp, int *cur_index, 231 char *buffer, int buffer_size, int *cur_len, 232 const char *format, ...) 233 { 234 va_list args; 235 236 /* 237 * We check against num_envp - 1 to make sure there is at 238 * least one slot left after we return, since kobject_uevent() 239 * needs to set the last slot to NULL. 240 */ 241 if (*cur_index >= num_envp - 1) 242 return -ENOMEM; 243 244 envp[*cur_index] = buffer + *cur_len; 245 246 va_start(args, format); 247 *cur_len += vsnprintf(envp[*cur_index], 248 max(buffer_size - *cur_len, 0), 249 format, args) + 1; 250 va_end(args); 251 252 if (*cur_len > buffer_size) 253 return -ENOMEM; 254 255 (*cur_index)++; 256 return 0; 257 } 258 EXPORT_SYMBOL_GPL(add_uevent_var); 259 260 #if defined(CONFIG_NET) 261 static int __init kobject_uevent_init(void) 262 { 263 uevent_sock = netlink_kernel_create(NETLINK_KOBJECT_UEVENT, 1, NULL, 264 THIS_MODULE); 265 266 if (!uevent_sock) { 267 printk(KERN_ERR 268 "kobject_uevent: unable to create netlink socket!\n"); 269 return -ENODEV; 270 } 271 272 return 0; 273 } 274 275 postcore_initcall(kobject_uevent_init); 276 #endif 277 278 #endif /* CONFIG_HOTPLUG */ 279