/* * kernel userspace event delivery * * Copyright (C) 2004 Red Hat, Inc. All rights reserved. * Copyright (C) 2004 Novell, Inc. All rights reserved. * Copyright (C) 2004 IBM, Inc. All rights reserved. * * Licensed under the GNU GPL v2. * * Authors: * Robert Love <rml@novell.com> * Kay Sievers <kay.sievers@vrfy.org> * Arjan van de Ven <arjanv@redhat.com> * Greg Kroah-Hartman <greg@kroah.com> */ #include <linux/spinlock.h> #include <linux/socket.h> #include <linux/skbuff.h> #include <linux/netlink.h> #include <linux/string.h> #include <linux/kobject.h> #include <net/sock.h> #define BUFFER_SIZE 2048 /* buffer for the variables */ #define NUM_ENVP 32 /* number of env pointers */ #if defined(CONFIG_HOTPLUG) u64 uevent_seqnum; char uevent_helper[UEVENT_HELPER_PATH_LEN] = "/sbin/hotplug"; static DEFINE_SPINLOCK(sequence_lock); #if defined(CONFIG_NET) static struct sock *uevent_sock; #endif /* the strings here must match the enum in include/linux/kobject.h */ const char *kobject_actions[] = { "add", "remove", "change", "move", "online", "offline", }; /** * kobject_uevent_env - send an uevent with environmental data * * @action: action that is happening (usually KOBJ_MOVE) * @kobj: struct kobject that the action is happening to * @envp_ext: pointer to environmental data * * Returns 0 if kobject_uevent() is completed with success or the * corresponding error when it fails. */ int kobject_uevent_env(struct kobject *kobj, enum kobject_action action, char *envp_ext[]) { char **envp; char *buffer; char *scratch; const char *action_string; const char *devpath = NULL; const char *subsystem; struct kobject *top_kobj; struct kset *kset; struct kset_uevent_ops *uevent_ops; u64 seq; char *seq_buff; int i = 0; int retval = 0; int j; pr_debug("%s\n", __FUNCTION__); action_string = kobject_actions[action]; if (!action_string) { pr_debug("kobject attempted to send uevent without action_string!\n"); return -EINVAL; } /* search the kset we belong to */ top_kobj = kobj; while (!top_kobj->kset && top_kobj->parent) { top_kobj = top_kobj->parent; } if (!top_kobj->kset) { pr_debug("kobject attempted to send uevent without kset!\n"); return -EINVAL; } kset = top_kobj->kset; uevent_ops = kset->uevent_ops; /* skip the event, if the filter returns zero. */ if (uevent_ops && uevent_ops->filter) if (!uevent_ops->filter(kset, kobj)) { pr_debug("kobject filter function caused the event to drop!\n"); return 0; } /* originating subsystem */ if (uevent_ops && uevent_ops->name) subsystem = uevent_ops->name(kset, kobj); else subsystem = kobject_name(&kset->kobj); if (!subsystem) { pr_debug("unset subsytem caused the event to drop!\n"); return 0; } /* environment index */ envp = kzalloc(NUM_ENVP * sizeof (char *), GFP_KERNEL); if (!envp) return -ENOMEM; /* environment values */ buffer = kmalloc(BUFFER_SIZE, GFP_KERNEL); if (!buffer) { retval = -ENOMEM; goto exit; } /* complete object path */ devpath = kobject_get_path(kobj, GFP_KERNEL); if (!devpath) { retval = -ENOENT; goto exit; } /* event environemnt for helper process only */ envp[i++] = "HOME=/"; envp[i++] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin"; /* default keys */ scratch = buffer; envp [i++] = scratch; scratch += sprintf(scratch, "ACTION=%s", action_string) + 1; envp [i++] = scratch; scratch += sprintf (scratch, "DEVPATH=%s", devpath) + 1; envp [i++] = scratch; scratch += sprintf(scratch, "SUBSYSTEM=%s", subsystem) + 1; for (j = 0; envp_ext && envp_ext[j]; j++) envp[i++] = envp_ext[j]; /* just reserve the space, overwrite it after kset call has returned */ envp[i++] = seq_buff = scratch; scratch += strlen("SEQNUM=18446744073709551616") + 1; /* let the kset specific function add its stuff */ if (uevent_ops && uevent_ops->uevent) { retval = uevent_ops->uevent(kset, kobj, &envp[i], NUM_ENVP - i, scratch, BUFFER_SIZE - (scratch - buffer)); if (retval) { pr_debug ("%s - uevent() returned %d\n", __FUNCTION__, retval); goto exit; } } /* we will send an event, request a new sequence number */ spin_lock(&sequence_lock); seq = ++uevent_seqnum; spin_unlock(&sequence_lock); sprintf(seq_buff, "SEQNUM=%llu", (unsigned long long)seq); #if defined(CONFIG_NET) /* send netlink message */ if (uevent_sock) { struct sk_buff *skb; size_t len; /* allocate message with the maximum possible size */ len = strlen(action_string) + strlen(devpath) + 2; skb = alloc_skb(len + BUFFER_SIZE, GFP_KERNEL); if (skb) { /* add header */ scratch = skb_put(skb, len); sprintf(scratch, "%s@%s", action_string, devpath); /* copy keys to our continuous event payload buffer */ for (i = 2; envp[i]; i++) { len = strlen(envp[i]) + 1; scratch = skb_put(skb, len); strcpy(scratch, envp[i]); } NETLINK_CB(skb).dst_group = 1; netlink_broadcast(uevent_sock, skb, 0, 1, GFP_KERNEL); } } #endif /* call uevent_helper, usually only enabled during early boot */ if (uevent_helper[0]) { char *argv [3]; argv [0] = uevent_helper; argv [1] = (char *)subsystem; argv [2] = NULL; call_usermodehelper (argv[0], argv, envp, UMH_WAIT_EXEC); } exit: kfree(devpath); kfree(buffer); kfree(envp); return retval; } EXPORT_SYMBOL_GPL(kobject_uevent_env); /** * kobject_uevent - notify userspace by ending an uevent * * @action: action that is happening (usually KOBJ_ADD and KOBJ_REMOVE) * @kobj: struct kobject that the action is happening to * * Returns 0 if kobject_uevent() is completed with success or the * corresponding error when it fails. */ int kobject_uevent(struct kobject *kobj, enum kobject_action action) { return kobject_uevent_env(kobj, action, NULL); } EXPORT_SYMBOL_GPL(kobject_uevent); /** * add_uevent_var - helper for creating event variables * @envp: Pointer to table of environment variables, as passed into * uevent() method. * @num_envp: Number of environment variable slots available, as * passed into uevent() method. * @cur_index: Pointer to current index into @envp. It should be * initialized to 0 before the first call to add_uevent_var(), * and will be incremented on success. * @buffer: Pointer to buffer for environment variables, as passed * into uevent() method. * @buffer_size: Length of @buffer, as passed into uevent() method. * @cur_len: Pointer to current length of space used in @buffer. * Should be initialized to 0 before the first call to * add_uevent_var(), and will be incremented on success. * @format: Format for creating environment variable (of the form * "XXX=%x") for snprintf(). * * Returns 0 if environment variable was added successfully or -ENOMEM * if no space was available. */ int add_uevent_var(char **envp, int num_envp, int *cur_index, char *buffer, int buffer_size, int *cur_len, const char *format, ...) { va_list args; /* * We check against num_envp - 1 to make sure there is at * least one slot left after we return, since kobject_uevent() * needs to set the last slot to NULL. */ if (*cur_index >= num_envp - 1) return -ENOMEM; envp[*cur_index] = buffer + *cur_len; va_start(args, format); *cur_len += vsnprintf(envp[*cur_index], max(buffer_size - *cur_len, 0), format, args) + 1; va_end(args); if (*cur_len > buffer_size) return -ENOMEM; (*cur_index)++; return 0; } EXPORT_SYMBOL_GPL(add_uevent_var); #if defined(CONFIG_NET) static int __init kobject_uevent_init(void) { uevent_sock = netlink_kernel_create(NETLINK_KOBJECT_UEVENT, 1, NULL, NULL, THIS_MODULE); if (!uevent_sock) { printk(KERN_ERR "kobject_uevent: unable to create netlink socket!\n"); return -ENODEV; } return 0; } postcore_initcall(kobject_uevent_init); #endif #endif /* CONFIG_HOTPLUG */