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_MOUNT: 42 return "mount"; 43 case KOBJ_UMOUNT: 44 return "umount"; 45 case KOBJ_OFFLINE: 46 return "offline"; 47 case KOBJ_ONLINE: 48 return "online"; 49 default: 50 return NULL; 51 } 52 } 53 54 /** 55 * kobject_uevent - notify userspace by ending an uevent 56 * 57 * @action: action that is happening (usually KOBJ_ADD and KOBJ_REMOVE) 58 * @kobj: struct kobject that the action is happening to 59 */ 60 void kobject_uevent(struct kobject *kobj, enum kobject_action action) 61 { 62 char **envp; 63 char *buffer; 64 char *scratch; 65 const char *action_string; 66 const char *devpath = NULL; 67 const char *subsystem; 68 struct kobject *top_kobj; 69 struct kset *kset; 70 struct kset_uevent_ops *uevent_ops; 71 u64 seq; 72 char *seq_buff; 73 int i = 0; 74 int retval; 75 76 pr_debug("%s\n", __FUNCTION__); 77 78 action_string = action_to_string(action); 79 if (!action_string) 80 return; 81 82 /* search the kset we belong to */ 83 top_kobj = kobj; 84 if (!top_kobj->kset && top_kobj->parent) { 85 do { 86 top_kobj = top_kobj->parent; 87 } while (!top_kobj->kset && top_kobj->parent); 88 } 89 if (!top_kobj->kset) 90 return; 91 92 kset = top_kobj->kset; 93 uevent_ops = kset->uevent_ops; 94 95 /* skip the event, if the filter returns zero. */ 96 if (uevent_ops && uevent_ops->filter) 97 if (!uevent_ops->filter(kset, kobj)) 98 return; 99 100 /* environment index */ 101 envp = kzalloc(NUM_ENVP * sizeof (char *), GFP_KERNEL); 102 if (!envp) 103 return; 104 105 /* environment values */ 106 buffer = kmalloc(BUFFER_SIZE, GFP_KERNEL); 107 if (!buffer) 108 goto exit; 109 110 /* complete object path */ 111 devpath = kobject_get_path(kobj, GFP_KERNEL); 112 if (!devpath) 113 goto exit; 114 115 /* originating subsystem */ 116 if (uevent_ops && uevent_ops->name) 117 subsystem = uevent_ops->name(kset, kobj); 118 else 119 subsystem = kobject_name(&kset->kobj); 120 121 /* event environemnt for helper process only */ 122 envp[i++] = "HOME=/"; 123 envp[i++] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin"; 124 125 /* default keys */ 126 scratch = buffer; 127 envp [i++] = scratch; 128 scratch += sprintf(scratch, "ACTION=%s", action_string) + 1; 129 envp [i++] = scratch; 130 scratch += sprintf (scratch, "DEVPATH=%s", devpath) + 1; 131 envp [i++] = scratch; 132 scratch += sprintf(scratch, "SUBSYSTEM=%s", subsystem) + 1; 133 134 /* just reserve the space, overwrite it after kset call has returned */ 135 envp[i++] = seq_buff = scratch; 136 scratch += strlen("SEQNUM=18446744073709551616") + 1; 137 138 /* let the kset specific function add its stuff */ 139 if (uevent_ops && uevent_ops->uevent) { 140 retval = uevent_ops->uevent(kset, kobj, 141 &envp[i], NUM_ENVP - i, scratch, 142 BUFFER_SIZE - (scratch - buffer)); 143 if (retval) { 144 pr_debug ("%s - uevent() returned %d\n", 145 __FUNCTION__, retval); 146 goto exit; 147 } 148 } 149 150 /* we will send an event, request a new sequence number */ 151 spin_lock(&sequence_lock); 152 seq = ++uevent_seqnum; 153 spin_unlock(&sequence_lock); 154 sprintf(seq_buff, "SEQNUM=%llu", (unsigned long long)seq); 155 156 /* send netlink message */ 157 if (uevent_sock) { 158 struct sk_buff *skb; 159 size_t len; 160 161 /* allocate message with the maximum possible size */ 162 len = strlen(action_string) + strlen(devpath) + 2; 163 skb = alloc_skb(len + BUFFER_SIZE, GFP_KERNEL); 164 if (skb) { 165 /* add header */ 166 scratch = skb_put(skb, len); 167 sprintf(scratch, "%s@%s", action_string, devpath); 168 169 /* copy keys to our continuous event payload buffer */ 170 for (i = 2; envp[i]; i++) { 171 len = strlen(envp[i]) + 1; 172 scratch = skb_put(skb, len); 173 strcpy(scratch, envp[i]); 174 } 175 176 NETLINK_CB(skb).dst_group = 1; 177 netlink_broadcast(uevent_sock, skb, 0, 1, GFP_KERNEL); 178 } 179 } 180 181 /* call uevent_helper, usually only enabled during early boot */ 182 if (uevent_helper[0]) { 183 char *argv [3]; 184 185 argv [0] = uevent_helper; 186 argv [1] = (char *)subsystem; 187 argv [2] = NULL; 188 call_usermodehelper (argv[0], argv, envp, 0); 189 } 190 191 exit: 192 kfree(devpath); 193 kfree(buffer); 194 kfree(envp); 195 return; 196 } 197 EXPORT_SYMBOL_GPL(kobject_uevent); 198 199 /** 200 * add_uevent_var - helper for creating event variables 201 * @envp: Pointer to table of environment variables, as passed into 202 * uevent() method. 203 * @num_envp: Number of environment variable slots available, as 204 * passed into uevent() method. 205 * @cur_index: Pointer to current index into @envp. It should be 206 * initialized to 0 before the first call to add_uevent_var(), 207 * and will be incremented on success. 208 * @buffer: Pointer to buffer for environment variables, as passed 209 * into uevent() method. 210 * @buffer_size: Length of @buffer, as passed into uevent() method. 211 * @cur_len: Pointer to current length of space used in @buffer. 212 * Should be initialized to 0 before the first call to 213 * add_uevent_var(), and will be incremented on success. 214 * @format: Format for creating environment variable (of the form 215 * "XXX=%x") for snprintf(). 216 * 217 * Returns 0 if environment variable was added successfully or -ENOMEM 218 * if no space was available. 219 */ 220 int add_uevent_var(char **envp, int num_envp, int *cur_index, 221 char *buffer, int buffer_size, int *cur_len, 222 const char *format, ...) 223 { 224 va_list args; 225 226 /* 227 * We check against num_envp - 1 to make sure there is at 228 * least one slot left after we return, since kobject_uevent() 229 * needs to set the last slot to NULL. 230 */ 231 if (*cur_index >= num_envp - 1) 232 return -ENOMEM; 233 234 envp[*cur_index] = buffer + *cur_len; 235 236 va_start(args, format); 237 *cur_len += vsnprintf(envp[*cur_index], 238 max(buffer_size - *cur_len, 0), 239 format, args) + 1; 240 va_end(args); 241 242 if (*cur_len > buffer_size) 243 return -ENOMEM; 244 245 (*cur_index)++; 246 return 0; 247 } 248 EXPORT_SYMBOL_GPL(add_uevent_var); 249 250 static int __init kobject_uevent_init(void) 251 { 252 uevent_sock = netlink_kernel_create(NETLINK_KOBJECT_UEVENT, 1, NULL, 253 THIS_MODULE); 254 255 if (!uevent_sock) { 256 printk(KERN_ERR 257 "kobject_uevent: unable to create netlink socket!\n"); 258 return -ENODEV; 259 } 260 261 return 0; 262 } 263 264 postcore_initcall(kobject_uevent_init); 265 266 #endif /* CONFIG_HOTPLUG */ 267