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 u64 uevent_seqnum; 30 char uevent_helper[UEVENT_HELPER_PATH_LEN] = "/sbin/hotplug"; 31 static DEFINE_SPINLOCK(sequence_lock); 32 static struct sock *uevent_sock; 33 34 static char *action_to_string(enum kobject_action action) 35 { 36 switch (action) { 37 case KOBJ_ADD: 38 return "add"; 39 case KOBJ_REMOVE: 40 return "remove"; 41 case KOBJ_CHANGE: 42 return "change"; 43 case KOBJ_MOUNT: 44 return "mount"; 45 case KOBJ_UMOUNT: 46 return "umount"; 47 case KOBJ_OFFLINE: 48 return "offline"; 49 case KOBJ_ONLINE: 50 return "online"; 51 default: 52 return NULL; 53 } 54 } 55 56 /** 57 * kobject_uevent - notify userspace by ending an uevent 58 * 59 * @action: action that is happening (usually KOBJ_ADD and KOBJ_REMOVE) 60 * @kobj: struct kobject that the action is happening to 61 */ 62 void kobject_uevent(struct kobject *kobj, enum kobject_action action) 63 { 64 char **envp; 65 char *buffer; 66 char *scratch; 67 const char *action_string; 68 const char *devpath = NULL; 69 const char *subsystem; 70 struct kobject *top_kobj; 71 struct kset *kset; 72 struct kset_uevent_ops *uevent_ops; 73 u64 seq; 74 char *seq_buff; 75 int i = 0; 76 int retval; 77 78 pr_debug("%s\n", __FUNCTION__); 79 80 action_string = action_to_string(action); 81 if (!action_string) 82 return; 83 84 /* search the kset we belong to */ 85 top_kobj = kobj; 86 if (!top_kobj->kset && top_kobj->parent) { 87 do { 88 top_kobj = top_kobj->parent; 89 } while (!top_kobj->kset && top_kobj->parent); 90 } 91 if (!top_kobj->kset) 92 return; 93 94 kset = top_kobj->kset; 95 uevent_ops = kset->uevent_ops; 96 97 /* skip the event, if the filter returns zero. */ 98 if (uevent_ops && uevent_ops->filter) 99 if (!uevent_ops->filter(kset, kobj)) 100 return; 101 102 /* environment index */ 103 envp = kzalloc(NUM_ENVP * sizeof (char *), GFP_KERNEL); 104 if (!envp) 105 return; 106 107 /* environment values */ 108 buffer = kmalloc(BUFFER_SIZE, GFP_KERNEL); 109 if (!buffer) 110 goto exit; 111 112 /* complete object path */ 113 devpath = kobject_get_path(kobj, GFP_KERNEL); 114 if (!devpath) 115 goto exit; 116 117 /* originating subsystem */ 118 if (uevent_ops && uevent_ops->name) 119 subsystem = uevent_ops->name(kset, kobj); 120 else 121 subsystem = kobject_name(&kset->kobj); 122 123 /* event environemnt for helper process only */ 124 envp[i++] = "HOME=/"; 125 envp[i++] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin"; 126 127 /* default keys */ 128 scratch = buffer; 129 envp [i++] = scratch; 130 scratch += sprintf(scratch, "ACTION=%s", action_string) + 1; 131 envp [i++] = scratch; 132 scratch += sprintf (scratch, "DEVPATH=%s", devpath) + 1; 133 envp [i++] = scratch; 134 scratch += sprintf(scratch, "SUBSYSTEM=%s", subsystem) + 1; 135 136 /* just reserve the space, overwrite it after kset call has returned */ 137 envp[i++] = seq_buff = scratch; 138 scratch += strlen("SEQNUM=18446744073709551616") + 1; 139 140 /* let the kset specific function add its stuff */ 141 if (uevent_ops && uevent_ops->uevent) { 142 retval = uevent_ops->uevent(kset, kobj, 143 &envp[i], NUM_ENVP - i, scratch, 144 BUFFER_SIZE - (scratch - buffer)); 145 if (retval) { 146 pr_debug ("%s - uevent() returned %d\n", 147 __FUNCTION__, retval); 148 goto exit; 149 } 150 } 151 152 /* we will send an event, request a new sequence number */ 153 spin_lock(&sequence_lock); 154 seq = ++uevent_seqnum; 155 spin_unlock(&sequence_lock); 156 sprintf(seq_buff, "SEQNUM=%llu", (unsigned long long)seq); 157 158 /* send netlink message */ 159 if (uevent_sock) { 160 struct sk_buff *skb; 161 size_t len; 162 163 /* allocate message with the maximum possible size */ 164 len = strlen(action_string) + strlen(devpath) + 2; 165 skb = alloc_skb(len + BUFFER_SIZE, GFP_KERNEL); 166 if (skb) { 167 /* add header */ 168 scratch = skb_put(skb, len); 169 sprintf(scratch, "%s@%s", action_string, devpath); 170 171 /* copy keys to our continuous event payload buffer */ 172 for (i = 2; envp[i]; i++) { 173 len = strlen(envp[i]) + 1; 174 scratch = skb_put(skb, len); 175 strcpy(scratch, envp[i]); 176 } 177 178 NETLINK_CB(skb).dst_group = 1; 179 netlink_broadcast(uevent_sock, skb, 0, 1, GFP_KERNEL); 180 } 181 } 182 183 /* call uevent_helper, usually only enabled during early boot */ 184 if (uevent_helper[0]) { 185 char *argv [3]; 186 187 argv [0] = uevent_helper; 188 argv [1] = (char *)subsystem; 189 argv [2] = NULL; 190 call_usermodehelper (argv[0], argv, envp, 0); 191 } 192 193 exit: 194 kfree(devpath); 195 kfree(buffer); 196 kfree(envp); 197 return; 198 } 199 EXPORT_SYMBOL_GPL(kobject_uevent); 200 201 /** 202 * add_uevent_var - helper for creating event variables 203 * @envp: Pointer to table of environment variables, as passed into 204 * uevent() method. 205 * @num_envp: Number of environment variable slots available, as 206 * passed into uevent() method. 207 * @cur_index: Pointer to current index into @envp. It should be 208 * initialized to 0 before the first call to add_uevent_var(), 209 * and will be incremented on success. 210 * @buffer: Pointer to buffer for environment variables, as passed 211 * into uevent() method. 212 * @buffer_size: Length of @buffer, as passed into uevent() method. 213 * @cur_len: Pointer to current length of space used in @buffer. 214 * Should be initialized to 0 before the first call to 215 * add_uevent_var(), and will be incremented on success. 216 * @format: Format for creating environment variable (of the form 217 * "XXX=%x") for snprintf(). 218 * 219 * Returns 0 if environment variable was added successfully or -ENOMEM 220 * if no space was available. 221 */ 222 int add_uevent_var(char **envp, int num_envp, int *cur_index, 223 char *buffer, int buffer_size, int *cur_len, 224 const char *format, ...) 225 { 226 va_list args; 227 228 /* 229 * We check against num_envp - 1 to make sure there is at 230 * least one slot left after we return, since kobject_uevent() 231 * needs to set the last slot to NULL. 232 */ 233 if (*cur_index >= num_envp - 1) 234 return -ENOMEM; 235 236 envp[*cur_index] = buffer + *cur_len; 237 238 va_start(args, format); 239 *cur_len += vsnprintf(envp[*cur_index], 240 max(buffer_size - *cur_len, 0), 241 format, args) + 1; 242 va_end(args); 243 244 if (*cur_len > buffer_size) 245 return -ENOMEM; 246 247 (*cur_index)++; 248 return 0; 249 } 250 EXPORT_SYMBOL_GPL(add_uevent_var); 251 252 static int __init kobject_uevent_init(void) 253 { 254 uevent_sock = netlink_kernel_create(NETLINK_KOBJECT_UEVENT, 1, NULL, 255 THIS_MODULE); 256 257 if (!uevent_sock) { 258 printk(KERN_ERR 259 "kobject_uevent: unable to create netlink socket!\n"); 260 return -ENODEV; 261 } 262 263 return 0; 264 } 265 266 postcore_initcall(kobject_uevent_init); 267 268 #endif /* CONFIG_HOTPLUG */ 269