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 default: 54 return NULL; 55 } 56 } 57 58 /** 59 * kobject_uevent - notify userspace by ending an uevent 60 * 61 * @action: action that is happening (usually KOBJ_ADD and KOBJ_REMOVE) 62 * @kobj: struct kobject that the action is happening to 63 */ 64 void kobject_uevent(struct kobject *kobj, enum kobject_action action) 65 { 66 char **envp; 67 char *buffer; 68 char *scratch; 69 const char *action_string; 70 const char *devpath = NULL; 71 const char *subsystem; 72 struct kobject *top_kobj; 73 struct kset *kset; 74 struct kset_uevent_ops *uevent_ops; 75 u64 seq; 76 char *seq_buff; 77 int i = 0; 78 int retval; 79 80 pr_debug("%s\n", __FUNCTION__); 81 82 action_string = action_to_string(action); 83 if (!action_string) 84 return; 85 86 /* search the kset we belong to */ 87 top_kobj = kobj; 88 if (!top_kobj->kset && top_kobj->parent) { 89 do { 90 top_kobj = top_kobj->parent; 91 } while (!top_kobj->kset && top_kobj->parent); 92 } 93 if (!top_kobj->kset) 94 return; 95 96 kset = top_kobj->kset; 97 uevent_ops = kset->uevent_ops; 98 99 /* skip the event, if the filter returns zero. */ 100 if (uevent_ops && uevent_ops->filter) 101 if (!uevent_ops->filter(kset, kobj)) 102 return; 103 104 /* environment index */ 105 envp = kzalloc(NUM_ENVP * sizeof (char *), GFP_KERNEL); 106 if (!envp) 107 return; 108 109 /* environment values */ 110 buffer = kmalloc(BUFFER_SIZE, GFP_KERNEL); 111 if (!buffer) 112 goto exit; 113 114 /* complete object path */ 115 devpath = kobject_get_path(kobj, GFP_KERNEL); 116 if (!devpath) 117 goto exit; 118 119 /* originating subsystem */ 120 if (uevent_ops && uevent_ops->name) 121 subsystem = uevent_ops->name(kset, kobj); 122 else 123 subsystem = kobject_name(&kset->kobj); 124 125 /* event environemnt for helper process only */ 126 envp[i++] = "HOME=/"; 127 envp[i++] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin"; 128 129 /* default keys */ 130 scratch = buffer; 131 envp [i++] = scratch; 132 scratch += sprintf(scratch, "ACTION=%s", action_string) + 1; 133 envp [i++] = scratch; 134 scratch += sprintf (scratch, "DEVPATH=%s", devpath) + 1; 135 envp [i++] = scratch; 136 scratch += sprintf(scratch, "SUBSYSTEM=%s", subsystem) + 1; 137 138 /* just reserve the space, overwrite it after kset call has returned */ 139 envp[i++] = seq_buff = scratch; 140 scratch += strlen("SEQNUM=18446744073709551616") + 1; 141 142 /* let the kset specific function add its stuff */ 143 if (uevent_ops && uevent_ops->uevent) { 144 retval = uevent_ops->uevent(kset, kobj, 145 &envp[i], NUM_ENVP - i, scratch, 146 BUFFER_SIZE - (scratch - buffer)); 147 if (retval) { 148 pr_debug ("%s - uevent() returned %d\n", 149 __FUNCTION__, retval); 150 goto exit; 151 } 152 } 153 154 /* we will send an event, request a new sequence number */ 155 spin_lock(&sequence_lock); 156 seq = ++uevent_seqnum; 157 spin_unlock(&sequence_lock); 158 sprintf(seq_buff, "SEQNUM=%llu", (unsigned long long)seq); 159 160 #if defined(CONFIG_NET) 161 /* send netlink message */ 162 if (uevent_sock) { 163 struct sk_buff *skb; 164 size_t len; 165 166 /* allocate message with the maximum possible size */ 167 len = strlen(action_string) + strlen(devpath) + 2; 168 skb = alloc_skb(len + BUFFER_SIZE, GFP_KERNEL); 169 if (skb) { 170 /* add header */ 171 scratch = skb_put(skb, len); 172 sprintf(scratch, "%s@%s", action_string, devpath); 173 174 /* copy keys to our continuous event payload buffer */ 175 for (i = 2; envp[i]; i++) { 176 len = strlen(envp[i]) + 1; 177 scratch = skb_put(skb, len); 178 strcpy(scratch, envp[i]); 179 } 180 181 NETLINK_CB(skb).dst_group = 1; 182 netlink_broadcast(uevent_sock, skb, 0, 1, GFP_KERNEL); 183 } 184 } 185 #endif 186 187 /* call uevent_helper, usually only enabled during early boot */ 188 if (uevent_helper[0]) { 189 char *argv [3]; 190 191 argv [0] = uevent_helper; 192 argv [1] = (char *)subsystem; 193 argv [2] = NULL; 194 call_usermodehelper (argv[0], argv, envp, 0); 195 } 196 197 exit: 198 kfree(devpath); 199 kfree(buffer); 200 kfree(envp); 201 return; 202 } 203 EXPORT_SYMBOL_GPL(kobject_uevent); 204 205 /** 206 * add_uevent_var - helper for creating event variables 207 * @envp: Pointer to table of environment variables, as passed into 208 * uevent() method. 209 * @num_envp: Number of environment variable slots available, as 210 * passed into uevent() method. 211 * @cur_index: Pointer to current index into @envp. It should be 212 * initialized to 0 before the first call to add_uevent_var(), 213 * and will be incremented on success. 214 * @buffer: Pointer to buffer for environment variables, as passed 215 * into uevent() method. 216 * @buffer_size: Length of @buffer, as passed into uevent() method. 217 * @cur_len: Pointer to current length of space used in @buffer. 218 * Should be initialized to 0 before the first call to 219 * add_uevent_var(), and will be incremented on success. 220 * @format: Format for creating environment variable (of the form 221 * "XXX=%x") for snprintf(). 222 * 223 * Returns 0 if environment variable was added successfully or -ENOMEM 224 * if no space was available. 225 */ 226 int add_uevent_var(char **envp, int num_envp, int *cur_index, 227 char *buffer, int buffer_size, int *cur_len, 228 const char *format, ...) 229 { 230 va_list args; 231 232 /* 233 * We check against num_envp - 1 to make sure there is at 234 * least one slot left after we return, since kobject_uevent() 235 * needs to set the last slot to NULL. 236 */ 237 if (*cur_index >= num_envp - 1) 238 return -ENOMEM; 239 240 envp[*cur_index] = buffer + *cur_len; 241 242 va_start(args, format); 243 *cur_len += vsnprintf(envp[*cur_index], 244 max(buffer_size - *cur_len, 0), 245 format, args) + 1; 246 va_end(args); 247 248 if (*cur_len > buffer_size) 249 return -ENOMEM; 250 251 (*cur_index)++; 252 return 0; 253 } 254 EXPORT_SYMBOL_GPL(add_uevent_var); 255 256 #if defined(CONFIG_NET) 257 static int __init kobject_uevent_init(void) 258 { 259 uevent_sock = netlink_kernel_create(NETLINK_KOBJECT_UEVENT, 1, NULL, 260 THIS_MODULE); 261 262 if (!uevent_sock) { 263 printk(KERN_ERR 264 "kobject_uevent: unable to create netlink socket!\n"); 265 return -ENODEV; 266 } 267 268 return 0; 269 } 270 271 postcore_initcall(kobject_uevent_init); 272 #endif 273 274 #endif /* CONFIG_HOTPLUG */ 275