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Commit 86d56134 authored by Michael Marineau's avatar Michael Marineau Committed by Greg Kroah-Hartman
Browse files

kobject: Make support for uevent_helper optional. 



Support for uevent_helper, aka hotplug, is not required on many systems
these days but it can still be enabled via sysfs or sysctl.

Reported-by: default avatarDarren Shepherd <darren.s.shepherd@gmail.com>
Signed-off-by: default avatarMichael Marineau <mike@marineau.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent d911d987

drivers/base/Kconfig

+11 −6
Original line number Diff line number Diff line 
menu "Generic Driver Options"



config UEVENT_HELPER_PATH

	string "path to uevent helper"

	default ""

config UEVENT_HELPER

	bool "Support for uevent helper"

	default y

	help

	  Path to uevent helper program forked by the kernel for

	  The uevent helper program is forked by the kernel for

	  every uevent.

	  Before the switch to the netlink-based uevent source, this was

	  used to hook hotplug scripts into kernel device events. It
@@ -15,8 +15,13 @@ config UEVENT_HELPER_PATH 
	  that it creates a high system load, or on smaller systems

	  it is known to create out-of-memory situations during bootup.



	  To disable user space helper program execution at early boot

	  time specify an empty string here. This setting can be altered

config UEVENT_HELPER_PATH

	string "path to uevent helper"

	depends on UEVENT_HELPER

	default ""

	help

	  To disable user space helper program execution at by default

	  specify an empty string here. This setting can still be altered

	  via /proc/sys/kernel/hotplug or via /sys/kernel/uevent_helper

	  later at runtime.

include/linux/kobject.h

+2 −0
Original line number Diff line number Diff line
@@ -32,8 +32,10 @@ 
#define UEVENT_NUM_ENVP			32	/* number of env pointers */

#define UEVENT_BUFFER_SIZE		2048	/* buffer for the variables */



#ifdef CONFIG_UEVENT_HELPER

/* path to the userspace helper executed on an event */

extern char uevent_helper[];

#endif



/* counter to tag the uevent, read only except for the kobject core */

extern u64 uevent_seqnum;

kernel/ksysfs.c

+4 −1
Original line number Diff line number Diff line
@@ -37,6 +37,7 @@ static ssize_t uevent_seqnum_show(struct kobject *kobj, 
}

KERNEL_ATTR_RO(uevent_seqnum);



#ifdef CONFIG_UEVENT_HELPER

/* uevent helper program, used during early boot */

static ssize_t uevent_helper_show(struct kobject *kobj,

				  struct kobj_attribute *attr, char *buf)
@@ -56,7 +57,7 @@ static ssize_t uevent_helper_store(struct kobject *kobj, 
	return count;

}

KERNEL_ATTR_RW(uevent_helper);



#endif



#ifdef CONFIG_PROFILING

static ssize_t profiling_show(struct kobject *kobj,
@@ -189,7 +190,9 @@ EXPORT_SYMBOL_GPL(kernel_kobj); 
static struct attribute * kernel_attrs[] = {

	&fscaps_attr.attr,

	&uevent_seqnum_attr.attr,

#ifdef CONFIG_UEVENT_HELPER

	&uevent_helper_attr.attr,

#endif

#ifdef CONFIG_PROFILING

	&profiling_attr.attr,

#endif

kernel/sysctl.c

+2 −2
Original line number Diff line number Diff line
@@ -643,7 +643,7 @@ static struct ctl_table kern_table[] = { 
		.extra2		= &one,

	},

#endif



#ifdef CONFIG_UEVENT_HELPER

	{

		.procname	= "hotplug",

		.data		= &uevent_helper,
@@ -651,7 +651,7 @@ static struct ctl_table kern_table[] = { 
		.mode		= 0644,

		.proc_handler	= proc_dostring,

	},



#endif

#ifdef CONFIG_CHR_DEV_SG

	{

		.procname	= "sg-big-buff",

lib/kobject_uevent.c

+6 −0
Original line number Diff line number Diff line
@@ -29,7 +29,9 @@ 




u64 uevent_seqnum;

#ifdef CONFIG_UEVENT_HELPER

char uevent_helper[UEVENT_HELPER_PATH_LEN] = CONFIG_UEVENT_HELPER_PATH;

#endif

#ifdef CONFIG_NET

struct uevent_sock {

	struct list_head list;
@@ -109,6 +111,7 @@ static int kobj_bcast_filter(struct sock *dsk, struct sk_buff *skb, void *data) 
}

#endif



#ifdef CONFIG_UEVENT_HELPER

static int kobj_usermode_filter(struct kobject *kobj)

{

	const struct kobj_ns_type_operations *ops;
@@ -147,6 +150,7 @@ static void cleanup_uevent_env(struct subprocess_info *info) 
{

	kfree(info->data);

}

#endif



/**

 * kobject_uevent_env - send an uevent with environmental data
@@ -323,6 +327,7 @@ int kobject_uevent_env(struct kobject *kobj, enum kobject_action action, 
#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;
@@ -347,6 +352,7 @@ int kobject_uevent_env(struct kobject *kobj, enum kobject_action action, 
			env = NULL;	/* freed by cleanup_uevent_env */

		}

	}

#endif



exit:

	kfree(devpath);