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) && defined(CONFIG_NET) 29 static DEFINE_SPINLOCK(sequence_lock); 30 static struct sock *uevent_sock; 31 32 static char *action_to_string(enum kobject_action action) 33 { 34 switch (action) { 35 case KOBJ_ADD: 36 return "add"; 37 case KOBJ_REMOVE: 38 return "remove"; 39 case KOBJ_CHANGE: 40 return "change"; 41 case KOBJ_OFFLINE: 42 return "offline"; 43 case KOBJ_ONLINE: 44 return "online"; 45 default: 46 return NULL; 47 } 48 } 49 50 /** 51 * kobject_uevent - notify userspace by ending an uevent 52 * 53 * @action: action that is happening (usually KOBJ_ADD and KOBJ_REMOVE) 54 * @kobj: struct kobject that the action is happening to 55 */ 56 void kobject_uevent(struct kobject *kobj, enum kobject_action action) 57 { 58 char **envp; 59 char *buffer; 60 char *scratch; 61 const char *action_string; 62 const char *devpath = NULL; 63 const char *subsystem; 64 struct kobject *top_kobj; 65 struct kset *kset; 66 struct kset_uevent_ops *uevent_ops; 67 u64 seq; 68 char *seq_buff; 69 int i = 0; 70 int retval; 71 72 pr_debug("%s\n", __FUNCTION__); 73 74 action_string = action_to_string(action); 75 if (!action_string) 76 return; 77 78 /* search the kset we belong to */ 79 top_kobj = kobj; 80 if (!top_kobj->kset && top_kobj->parent) { 81 do { 82 top_kobj = top_kobj->parent; 83 } while (!top_kobj->kset && top_kobj->parent); 84 } 85 if (!top_kobj->kset) 86 return; 87 88 kset = top_kobj->kset; 89 uevent_ops = kset->uevent_ops; 90 91 /* skip the event, if the filter returns zero. */ 92 if (uevent_ops && uevent_ops->filter) 93 if (!uevent_ops->filter(kset, kobj)) 94 return; 95 96 /* environment index */ 97 envp = kzalloc(NUM_ENVP * sizeof (char *), GFP_KERNEL); 98 if (!envp) 99 return; 100 101 /* environment values */ 102 buffer = kmalloc(BUFFER_SIZE, GFP_KERNEL); 103 if (!buffer) 104 goto exit; 105 106 /* complete object path */ 107 devpath = kobject_get_path(kobj, GFP_KERNEL); 108 if (!devpath) 109 goto exit; 110 111 /* originating subsystem */ 112 if (uevent_ops && uevent_ops->name) 113 subsystem = uevent_ops->name(kset, kobj); 114 else 115 subsystem = kobject_name(&kset->kobj); 116 117 /* event environemnt for helper process only */ 118 envp[i++] = "HOME=/"; 119 envp[i++] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin"; 120 121 /* default keys */ 122 scratch = buffer; 123 envp [i++] = scratch; 124 scratch += sprintf(scratch, "ACTION=%s", action_string) + 1; 125 envp [i++] = scratch; 126 scratch += sprintf (scratch, "DEVPATH=%s", devpath) + 1; 127 envp [i++] = scratch; 128 scratch += sprintf(scratch, "SUBSYSTEM=%s", subsystem) + 1; 129 130 /* just reserve the space, overwrite it after kset call has returned */ 131 envp[i++] = seq_buff = scratch; 132 scratch += strlen("SEQNUM=18446744073709551616") + 1; 133 134 /* let the kset specific function add its stuff */ 135 if (uevent_ops && uevent_ops->uevent) { 136 retval = uevent_ops->uevent(kset, kobj, 137 &envp[i], NUM_ENVP - i, scratch, 138 BUFFER_SIZE - (scratch - buffer)); 139 if (retval) { 140 pr_debug ("%s - uevent() returned %d\n", 141 __FUNCTION__, retval); 142 goto exit; 143 } 144 } 145 146 /* we will send an event, request a new sequence number */ 147 spin_lock(&sequence_lock); 148 seq = ++uevent_seqnum; 149 spin_unlock(&sequence_lock); 150 sprintf(seq_buff, "SEQNUM=%llu", (unsigned long long)seq); 151 152 /* send netlink message */ 153 if (uevent_sock) { 154 struct sk_buff *skb; 155 size_t len; 156 157 /* allocate message with the maximum possible size */ 158 len = strlen(action_string) + strlen(devpath) + 2; 159 skb = alloc_skb(len + BUFFER_SIZE, GFP_KERNEL); 160 if (skb) { 161 /* add header */ 162 scratch = skb_put(skb, len); 163 sprintf(scratch, "%s@%s", action_string, devpath); 164 165 /* copy keys to our continuous event payload buffer */ 166 for (i = 2; envp[i]; i++) { 167 len = strlen(envp[i]) + 1; 168 scratch = skb_put(skb, len); 169 strcpy(scratch, envp[i]); 170 } 171 172 NETLINK_CB(skb).dst_group = 1; 173 netlink_broadcast(uevent_sock, skb, 0, 1, GFP_KERNEL); 174 } 175 } 176 177 /* call uevent_helper, usually only enabled during early boot */ 178 if (uevent_helper[0]) { 179 char *argv [3]; 180 181 argv [0] = uevent_helper; 182 argv [1] = (char *)subsystem; 183 argv [2] = NULL; 184 call_usermodehelper (argv[0], argv, envp, 0); 185 } 186 187 exit: 188 kfree(devpath); 189 kfree(buffer); 190 kfree(envp); 191 return; 192 } 193 EXPORT_SYMBOL_GPL(kobject_uevent); 194 195 /** 196 * add_uevent_var - helper for creating event variables 197 * @envp: Pointer to table of environment variables, as passed into 198 * uevent() method. 199 * @num_envp: Number of environment variable slots available, as 200 * passed into uevent() method. 201 * @cur_index: Pointer to current index into @envp. It should be 202 * initialized to 0 before the first call to add_uevent_var(), 203 * and will be incremented on success. 204 * @buffer: Pointer to buffer for environment variables, as passed 205 * into uevent() method. 206 * @buffer_size: Length of @buffer, as passed into uevent() method. 207 * @cur_len: Pointer to current length of space used in @buffer. 208 * Should be initialized to 0 before the first call to 209 * add_uevent_var(), and will be incremented on success. 210 * @format: Format for creating environment variable (of the form 211 * "XXX=%x") for snprintf(). 212 * 213 * Returns 0 if environment variable was added successfully or -ENOMEM 214 * if no space was available. 215 */ 216 int add_uevent_var(char **envp, int num_envp, int *cur_index, 217 char *buffer, int buffer_size, int *cur_len, 218 const char *format, ...) 219 { 220 va_list args; 221 222 /* 223 * We check against num_envp - 1 to make sure there is at 224 * least one slot left after we return, since kobject_uevent() 225 * needs to set the last slot to NULL. 226 */ 227 if (*cur_index >= num_envp - 1) 228 return -ENOMEM; 229 230 envp[*cur_index] = buffer + *cur_len; 231 232 va_start(args, format); 233 *cur_len += vsnprintf(envp[*cur_index], 234 max(buffer_size - *cur_len, 0), 235 format, args) + 1; 236 va_end(args); 237 238 if (*cur_len > buffer_size) 239 return -ENOMEM; 240 241 (*cur_index)++; 242 return 0; 243 } 244 EXPORT_SYMBOL_GPL(add_uevent_var); 245 246 static int __init kobject_uevent_init(void) 247 { 248 uevent_sock = netlink_kernel_create(NETLINK_KOBJECT_UEVENT, 1, NULL, 249 THIS_MODULE); 250 251 if (!uevent_sock) { 252 printk(KERN_ERR 253 "kobject_uevent: unable to create netlink socket!\n"); 254 return -ENODEV; 255 } 256 257 return 0; 258 } 259 260 postcore_initcall(kobject_uevent_init); 261 262 #endif /* CONFIG_HOTPLUG */ 263