cregit-Linux how code gets into the kernel

Release 4.8 lib/kobject_uevent.c

Directory: lib
 * 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             <>
 *      Kay Sievers             <>
 *      Arjan van de Ven        <>
 *      Greg Kroah-Hartman      <>

#include <linux/spinlock.h>
#include <linux/string.h>
#include <linux/kobject.h>
#include <linux/export.h>
#include <linux/kmod.h>
#include <linux/slab.h>
#include <linux/socket.h>
#include <linux/skbuff.h>
#include <linux/netlink.h>
#include <net/sock.h>
#include <net/net_namespace.h>

u64 uevent_seqnum;


struct uevent_sock {
struct list_head list;
struct sock *sk;
static LIST_HEAD(uevent_sock_list);

/* This lock protects uevent_seqnum and uevent_sock_list */
static DEFINE_MUTEX(uevent_sock_mutex);

/* the strings here must match the enum in include/linux/kobject.h */

static const char *kobject_actions[] = {
	[KOBJ_ADD] =		"add",
	[KOBJ_REMOVE] =		"remove",
	[KOBJ_CHANGE] =		"change",
	[KOBJ_MOVE] =		"move",
	[KOBJ_ONLINE] =		"online",
	[KOBJ_OFFLINE] =	"offline",

 * kobject_action_type - translate action string to numeric type
 * @buf: buffer containing the action string, newline is ignored
 * @len: length of buffer
 * @type: pointer to the location to store the action type
 * Returns 0 if the action string was recognized.

int kobject_action_type(const char *buf, size_t count, enum kobject_action *type) { enum kobject_action action; int ret = -EINVAL; if (count && (buf[count-1] == '\n' || buf[count-1] == '\0')) count--; if (!count) goto out; for (action = 0; action < ARRAY_SIZE(kobject_actions); action++) { if (strncmp(kobject_actions[action], buf, count) != 0) continue; if (kobject_actions[action][count] != '\0') continue; *type = action; ret = 0; break; } out: return ret; }


kay sieverskay sievers11591.27%150.00%
mark lordmark lord118.73%150.00%

static int kobj_bcast_filter(struct sock *dsk, struct sk_buff *skb, void *data) { struct kobject *kobj = data, *ksobj; const struct kobj_ns_type_operations *ops; ops = kobj_ns_ops(kobj); if (!ops && kobj->kset) { ksobj = &kobj->kset->kobj; if (ksobj->parent != NULL) ops = kobj_ns_ops(ksobj->parent); } if (ops && ops->netlink_ns && kobj->ktype->namespace) { const void *sock_ns, *ns; ns = kobj->ktype->namespace(kobj); sock_ns = ops->netlink_ns(dsk); return sock_ns != ns; } return 0; }


eric w. biedermaneric w. biederman8262.12%150.00%
chen weilongchen weilong5037.88%150.00%

static int kobj_usermode_filter(struct kobject *kobj) { const struct kobj_ns_type_operations *ops; ops = kobj_ns_ops(kobj); if (ops) { const void *init_ns, *ns; ns = kobj->ktype->namespace(kobj); init_ns = ops->initial_ns(); return ns != init_ns; } return 0; }


eric w. biedermaneric w. biederman64100.00%1100.00%

static int init_uevent_argv(struct kobj_uevent_env *env, const char *subsystem) { int len; len = strlcpy(&env->buf[env->buflen], subsystem, sizeof(env->buf) - env->buflen); if (len >= (sizeof(env->buf) - env->buflen)) { WARN(1, KERN_ERR "init_uevent_argv: buffer size too small\n"); return -ENOMEM; } env->argv[0] = uevent_helper; env->argv[1] = &env->buf[env->buflen]; env->argv[2] = NULL; env->buflen += len + 1; return 0; }


vladimir davydovvladimir davydov124100.00%1100.00%

static void cleanup_uevent_env(struct subprocess_info *info) { kfree(info->data); }


vladimir davydovvladimir davydov18100.00%1100.00%

#endif /** * kobject_uevent_env - send an uevent with environmental data * * @action: action that is happening * @kobj: struct kobject that the action is happening to * @envp_ext: pointer to environmental data * * Returns 0 if kobject_uevent_env() 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[]) { struct kobj_uevent_env *env; const char *action_string = kobject_actions[action]; const char *devpath = NULL; const char *subsystem; struct kobject *top_kobj; struct kset *kset; const struct kset_uevent_ops *uevent_ops; int i = 0; int retval = 0; #ifdef CONFIG_NET struct uevent_sock *ue_sk; #endif pr_debug("kobject: '%s' (%p): %s\n", kobject_name(kobj), kobj, __func__); /* 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: '%s' (%p): %s: attempted to send uevent " "without kset!\n", kobject_name(kobj), kobj, __func__); return -EINVAL; } kset = top_kobj->kset; uevent_ops = kset->uevent_ops; /* skip the event, if uevent_suppress is set*/ if (kobj->uevent_suppress) { pr_debug("kobject: '%s' (%p): %s: uevent_suppress " "caused the event to drop!\n", kobject_name(kobj), kobj, __func__); return 0; } /* skip the event, if the filter returns zero. */ if (uevent_ops && uevent_ops->filter) if (!uevent_ops->filter(kset, kobj)) { pr_debug("kobject: '%s' (%p): %s: filter function " "caused the event to drop!\n", kobject_name(kobj), kobj, __func__); 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("kobject: '%s' (%p): %s: unset subsystem caused the " "event to drop!\n", kobject_name(kobj), kobj, __func__); return 0; } /* environment buffer */ env = kzalloc(sizeof(struct kobj_uevent_env), GFP_KERNEL); if (!env) return -ENOMEM; /* complete object path */ devpath = kobject_get_path(kobj, GFP_KERNEL); if (!devpath) { retval = -ENOENT; goto exit; } /* default keys */ retval = add_uevent_var(env, "ACTION=%s", action_string); if (retval) goto exit; retval = add_uevent_var(env, "DEVPATH=%s", devpath); if (retval) goto exit; retval = add_uevent_var(env, "SUBSYSTEM=%s", subsystem); if (retval) goto exit; /* keys passed in from the caller */ if (envp_ext) { for (i = 0; envp_ext[i]; i++) { retval = add_uevent_var(env, "%s", envp_ext[i]); if (retval) goto exit; } } /* let the kset specific function add its stuff */ if (uevent_ops && uevent_ops->uevent) { retval = uevent_ops->uevent(kset, kobj, env); if (retval) { pr_debug("kobject: '%s' (%p): %s: uevent() returned " "%d\n", kobject_name(kobj), kobj, __func__, retval); goto exit; } } /* * Mark "add" and "remove" events in the object to ensure proper * events to userspace during automatic cleanup. If the object did * send an "add" event, "remove" will automatically generated by * the core, if not already done by the caller. */ if (action == KOBJ_ADD) kobj->state_add_uevent_sent = 1; else if (action == KOBJ_REMOVE) kobj->state_remove_uevent_sent = 1; mutex_lock(&uevent_sock_mutex); /* we will send an event, so request a new sequence number */ retval = add_uevent_var(env, "SEQNUM=%llu", (unsigned long long)++uevent_seqnum); if (retval) { mutex_unlock(&uevent_sock_mutex); goto exit; } #if defined(CONFIG_NET) /* send netlink message */ list_for_each_entry(ue_sk, &uevent_sock_list, list) { struct sock *uevent_sock = ue_sk->sk; struct sk_buff *skb; size_t len; if (!netlink_has_listeners(uevent_sock, 1)) continue; /* allocate message with the maximum possible size */ len = strlen(action_string) + strlen(devpath) + 2; skb = alloc_skb(len + env->buflen, GFP_KERNEL); if (skb) { char *scratch; /* add header */ scratch = skb_put(skb, len); sprintf(scratch, "%s@%s", action_string, devpath); /* copy keys to our continuous event payload buffer */ for (i = 0; i < env->envp_idx; i++) { len = strlen(env->envp[i]) + 1; scratch = skb_put(skb, len); strcpy(scratch, env->envp[i]); } NETLINK_CB(skb).dst_group = 1; retval = netlink_broadcast_filtered(uevent_sock, skb, 0, 1, GFP_KERNEL, kobj_bcast_filter, kobj); /* ENOBUFS should be handled in userspace */ if (retval == -ENOBUFS || retval == -ESRCH) retval = 0; } else retval = -ENOMEM; } #endif mutex_unlock(&uevent_sock_mutex); #ifdef CONFIG_UEVENT_HELPER /* call uevent_helper, usually only enabled during early boot */ if (uevent_helper[0] && !kobj_usermode_filter(kobj)) { struct subprocess_info *info; retval = add_uevent_var(env, "HOME=/"); if (retval) goto exit; retval = add_uevent_var(env, "PATH=/sbin:/bin:/usr/sbin:/usr/bin"); if (retval) goto exit; retval = init_uevent_argv(env, subsystem); if (retval) goto exit; retval = -ENOMEM; info = call_usermodehelper_setup(env->argv[0], env->argv, env->envp, GFP_KERNEL, NULL, cleanup_uevent_env, env); if (info) { retval = call_usermodehelper_exec(info, UMH_NO_WAIT); env = NULL; /* freed by cleanup_uevent_env */ } } #endif exit: kfree(devpath); kfree(env); return retval; }


kay sieverskay sievers38542.68%928.12%
greg kroah-hartmangreg kroah-hartman26729.60%412.50%
vladimir davydovvladimir davydov566.21%13.12%
eric w. biedermaneric w. biederman444.88%39.38%
aneesh kumaraneesh kumar363.99%13.12%
lei minglei ming353.88%26.25%
cornelia huckcornelia huck202.22%13.12%
andrey vaginandrey vagin151.66%13.12%
pablo neira ayusopablo neira ayuso121.33%13.12%
andrew mortonandrew morton101.11%13.12%
harvey harrisonharvey harrison50.55%13.12%
milan brozmilan broz50.55%13.12%
michael marineaumichael marineau50.55%13.12%
tejun heotejun heo20.22%13.12%
wang chenwang chen20.22%13.12%
dmitry torokhovdmitry torokhov10.11%13.12%
john anthony kazos jrjohn anthony kazos jr10.11%13.12%
emese revfyemese revfy10.11%13.12%

EXPORT_SYMBOL_GPL(kobject_uevent_env); /** * kobject_uevent - notify userspace by sending an uevent * * @action: action that is happening * @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); }


cornelia huckcornelia huck2187.50%150.00%
aneesh kumaraneesh kumar312.50%150.00%

EXPORT_SYMBOL_GPL(kobject_uevent); /** * add_uevent_var - add key value string to the environment buffer * @env: environment buffer structure * @format: printf format for the key=value pair * * Returns 0 if environment variable was added successfully or -ENOMEM * if no space was available. */
int add_uevent_var(struct kobj_uevent_env *env, const char *format, ...) { va_list args; int len; if (env->envp_idx >= ARRAY_SIZE(env->envp)) { WARN(1, KERN_ERR "add_uevent_var: too many keys\n"); return -ENOMEM; } va_start(args, format); len = vsnprintf(&env->buf[env->buflen], sizeof(env->buf) - env->buflen, format, args); va_end(args); if (len >= (sizeof(env->buf) - env->buflen)) { WARN(1, KERN_ERR "add_uevent_var: buffer size too small\n"); return -ENOMEM; } env->envp[env->envp_idx++] = &env->buf[env->buflen]; env->buflen += len + 1; return 0; }


kay sieverskay sievers8756.49%250.00%
roland dreierroland dreier6139.61%125.00%
arjan van de venarjan van de ven63.90%125.00%

EXPORT_SYMBOL_GPL(add_uevent_var); #if defined(CONFIG_NET)
static int uevent_net_init(struct net *net) { struct uevent_sock *ue_sk; struct netlink_kernel_cfg cfg = { .groups = 1, .flags = NL_CFG_F_NONROOT_RECV, }; ue_sk = kzalloc(sizeof(*ue_sk), GFP_KERNEL); if (!ue_sk) return -ENOMEM; ue_sk->sk = netlink_kernel_create(net, NETLINK_KOBJECT_UEVENT, &cfg); if (!ue_sk->sk) { printk(KERN_ERR "kobject_uevent: unable to create netlink socket!\n"); kfree(ue_sk); return -ENODEV; } mutex_lock(&uevent_sock_mutex); list_add_tail(&ue_sk->list, &uevent_sock_list); mutex_unlock(&uevent_sock_mutex); return 0; }


eric w. biedermaneric w. biederman6655.93%233.33%
kay sieverskay sievers2924.58%116.67%
pablo neira ayusopablo neira ayuso1815.25%233.33%
dan carpenterdan carpenter54.24%116.67%

static void uevent_net_exit(struct net *net) { struct uevent_sock *ue_sk; mutex_lock(&uevent_sock_mutex); list_for_each_entry(ue_sk, &uevent_sock_list, list) { if (sock_net(ue_sk->sk) == net) goto found; } mutex_unlock(&uevent_sock_mutex); return; found: list_del(&ue_sk->list); mutex_unlock(&uevent_sock_mutex); netlink_kernel_release(ue_sk->sk); kfree(ue_sk); }


eric w. biedermaneric w. biederman81100.00%1100.00%

static struct pernet_operations uevent_net_ops = { .init = uevent_net_init, .exit = uevent_net_exit, };
static int __init kobject_uevent_init(void) { return register_pernet_subsys(&uevent_net_ops); }


eric w. biedermaneric w. biederman1381.25%150.00%
kay sieverskay sievers318.75%150.00%

postcore_initcall(kobject_uevent_init); #endif

Overall Contributors

kay sieverskay sievers68535.20%1122.92%
eric w. biedermaneric w. biederman39420.25%48.33%
greg kroah-hartmangreg kroah-hartman29215.01%48.33%
vladimir davydovvladimir davydov19810.17%12.08%
roland dreierroland dreier643.29%12.08%
chen weilongchen weilong502.57%12.08%
cornelia huckcornelia huck462.36%12.08%
aneesh kumaraneesh kumar392.00%12.08%
lei minglei ming351.80%24.17%
pablo neira ayusopablo neira ayuso301.54%36.25%
andrey vaginandrey vagin180.92%12.08%
andrew mortonandrew morton150.77%24.17%
michael marineaumichael marineau150.77%12.08%
mark lordmark lord110.57%12.08%
jun'ichi nomurajun'ichi nomura100.51%12.08%
denis v. lunevdenis v. lunev70.36%12.08%
arjan van de venarjan van de ven60.31%12.08%
milan brozmilan broz50.26%12.08%
dan carpenterdan carpenter50.26%12.08%
harvey harrisonharvey harrison50.26%12.08%
tejun heotejun heo50.26%24.17%
paul gortmakerpaul gortmaker40.21%12.08%
wang chenwang chen20.10%12.08%
xiaotian fengxiaotian feng20.10%12.08%
dmitry torokhovdmitry torokhov10.05%12.08%
emese revfyemese revfy10.05%12.08%
john anthony kazos jrjohn anthony kazos jr10.05%12.08%
Directory: lib
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