/* * 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_uevent.h> #include <linux/kobject.h> #include <net/sock.h> #define BUFFER_SIZE 1024 /* buffer for the hotplug env */ #define NUM_ENVP 32 /* number of env pointers */ #if defined(CONFIG_KOBJECT_UEVENT) || defined(CONFIG_HOTPLUG) static char *action_to_string(enum kobject_action action) { switch (action) { case KOBJ_ADD: return "add"; case KOBJ_REMOVE: return "remove"; case KOBJ_CHANGE: return "change"; case KOBJ_MOUNT: return "mount"; case KOBJ_UMOUNT: return "umount"; case KOBJ_OFFLINE: return "offline"; case KOBJ_ONLINE: return "online"; default: return NULL; } } #endif #ifdef CONFIG_KOBJECT_UEVENT static struct sock *uevent_sock; /** * send_uevent - notify userspace by sending event through netlink socket * * @signal: signal name * @obj: object path (kobject) * @envp: possible hotplug environment to pass with the message * @gfp_mask: */ static int send_uevent(const char *signal, const char *obj, char **envp, gfp_t gfp_mask) { struct sk_buff *skb; char *pos; int len; if (!uevent_sock) return -EIO; len = strlen(signal) + 1; len += strlen(obj) + 1; /* allocate buffer with the maximum possible message size */ skb = alloc_skb(len + BUFFER_SIZE, gfp_mask); if (!skb) return -ENOMEM; pos = skb_put(skb, len); sprintf(pos, "%s@%s", signal, obj); /* copy the environment key by key to our continuous buffer */ if (envp) { int i; for (i = 2; envp[i]; i++) { len = strlen(envp[i]) + 1; pos = skb_put(skb, len); strcpy(pos, envp[i]); } } NETLINK_CB(skb).dst_group = 1; return netlink_broadcast(uevent_sock, skb, 0, 1, gfp_mask); } static int do_kobject_uevent(struct kobject *kobj, enum kobject_action action, struct attribute *attr, gfp_t gfp_mask) { char *path; char *attrpath; char *signal; int len; int rc = -ENOMEM; path = kobject_get_path(kobj, gfp_mask); if (!path) return -ENOMEM; signal = action_to_string(action); if (!signal) return -EINVAL; if (attr) { len = strlen(path); len += strlen(attr->name) + 2; attrpath = kmalloc(len, gfp_mask); if (!attrpath) goto exit; sprintf(attrpath, "%s/%s", path, attr->name); rc = send_uevent(signal, attrpath, NULL, gfp_mask); kfree(attrpath); } else rc = send_uevent(signal, path, NULL, gfp_mask); exit: kfree(path); return rc; } /** * kobject_uevent - notify userspace by sending event through netlink socket * * @signal: signal name * @kobj: struct kobject that the event is happening to * @attr: optional struct attribute the event belongs to */ int kobject_uevent(struct kobject *kobj, enum kobject_action action, struct attribute *attr) { return do_kobject_uevent(kobj, action, attr, GFP_KERNEL); } EXPORT_SYMBOL_GPL(kobject_uevent); int kobject_uevent_atomic(struct kobject *kobj, enum kobject_action action, struct attribute *attr) { return do_kobject_uevent(kobj, action, attr, GFP_ATOMIC); } EXPORT_SYMBOL_GPL(kobject_uevent_atomic); static int __init kobject_uevent_init(void) { uevent_sock = netlink_kernel_create(NETLINK_KOBJECT_UEVENT, 1, 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); #else static inline int send_uevent(const char *signal, const char *obj, char **envp, int gfp_mask) { return 0; } #endif /* CONFIG_KOBJECT_UEVENT */ #ifdef CONFIG_HOTPLUG char hotplug_path[HOTPLUG_PATH_LEN] = "/sbin/hotplug"; u64 hotplug_seqnum; static DEFINE_SPINLOCK(sequence_lock); /** * kobject_hotplug - notify userspace by executing /sbin/hotplug * * @action: action that is happening (usually "ADD" or "REMOVE") * @kobj: struct kobject that the action is happening to */ void kobject_hotplug(struct kobject *kobj, enum kobject_action action) { char *argv [3]; char **envp = NULL; char *buffer = NULL; char *seq_buff; char *scratch; int i = 0; int retval; char *kobj_path = NULL; const char *name = NULL; char *action_string; u64 seq; struct kobject *top_kobj = kobj; struct kset *kset; static struct kset_hotplug_ops null_hotplug_ops; struct kset_hotplug_ops *hotplug_ops = &null_hotplug_ops; /* If this kobj does not belong to a kset, try to find a parent that does. */ if (!top_kobj->kset && top_kobj->parent) { do { top_kobj = top_kobj->parent; } while (!top_kobj->kset && top_kobj->parent); } if (top_kobj->kset) kset = top_kobj->kset; else return; if (kset->hotplug_ops) hotplug_ops = kset->hotplug_ops; /* If the kset has a filter operation, call it. Skip the event, if the filter returns zero. */ if (hotplug_ops->filter) { if (!hotplug_ops->filter(kset, kobj)) return; } pr_debug ("%s\n", __FUNCTION__); action_string = action_to_string(action); if (!action_string) return; envp = kmalloc(NUM_ENVP * sizeof (char *), GFP_KERNEL); if (!envp) return; memset (envp, 0x00, NUM_ENVP * sizeof (char *)); buffer = kmalloc(BUFFER_SIZE, GFP_KERNEL); if (!buffer) goto exit; if (hotplug_ops->name) name = hotplug_ops->name(kset, kobj); if (name == NULL) name = kobject_name(&kset->kobj); argv [0] = hotplug_path; argv [1] = (char *)name; /* won't be changed but 'const' has to go */ argv [2] = NULL; /* minimal command environment */ envp [i++] = "HOME=/"; envp [i++] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin"; scratch = buffer; envp [i++] = scratch; scratch += sprintf(scratch, "ACTION=%s", action_string) + 1; kobj_path = kobject_get_path(kobj, GFP_KERNEL); if (!kobj_path) goto exit; envp [i++] = scratch; scratch += sprintf (scratch, "DEVPATH=%s", kobj_path) + 1; envp [i++] = scratch; scratch += sprintf(scratch, "SUBSYSTEM=%s", name) + 1; /* reserve space for the sequence, * put the real one in after the hotplug call */ envp[i++] = seq_buff = scratch; scratch += strlen("SEQNUM=18446744073709551616") + 1; if (hotplug_ops->hotplug) { /* have the kset specific function add its stuff */ retval = hotplug_ops->hotplug (kset, kobj, &envp[i], NUM_ENVP - i, scratch, BUFFER_SIZE - (scratch - buffer)); if (retval) { pr_debug ("%s - hotplug() returned %d\n", __FUNCTION__, retval); goto exit; } } spin_lock(&sequence_lock); seq = ++hotplug_seqnum; spin_unlock(&sequence_lock); sprintf(seq_buff, "SEQNUM=%llu", (unsigned long long)seq); pr_debug ("%s: %s %s seq=%llu %s %s %s %s %s\n", __FUNCTION__, argv[0], argv[1], (unsigned long long)seq, envp[0], envp[1], envp[2], envp[3], envp[4]); send_uevent(action_string, kobj_path, envp, GFP_KERNEL); if (!hotplug_path[0]) goto exit; retval = call_usermodehelper (argv[0], argv, envp, 0); if (retval) pr_debug ("%s - call_usermodehelper returned %d\n", __FUNCTION__, retval); exit: kfree(kobj_path); kfree(buffer); kfree(envp); return; } EXPORT_SYMBOL(kobject_hotplug); /** * add_hotplug_env_var - helper for creating hotplug environment variables * @envp: Pointer to table of environment variables, as passed into * hotplug() method. * @num_envp: Number of environment variable slots available, as * passed into hotplug() method. * @cur_index: Pointer to current index into @envp. It should be * initialized to 0 before the first call to add_hotplug_env_var(), * and will be incremented on success. * @buffer: Pointer to buffer for environment variables, as passed * into hotplug() method. * @buffer_size: Length of @buffer, as passed into hotplug() method. * @cur_len: Pointer to current length of space used in @buffer. * Should be initialized to 0 before the first call to * add_hotplug_env_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_hotplug_env_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 the hotplug * method 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(add_hotplug_env_var); #endif /* CONFIG_HOTPLUG */