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

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
menu "Generic Driver Options" menu "Generic Driver Options"
config UEVENT_HELPER_PATH config UEVENT_HELPER
string "path to uevent helper" bool "Support for uevent helper"
default "" default y
help help
Path to uevent helper program forked by the kernel for The uevent helper program is forked by the kernel for
every uevent. every uevent.
Before the switch to the netlink-based uevent source, this was Before the switch to the netlink-based uevent source, this was
used to hook hotplug scripts into kernel device events. It used to hook hotplug scripts into kernel device events. It
...@@ -15,8 +15,13 @@ config UEVENT_HELPER_PATH ...@@ -15,8 +15,13 @@ config UEVENT_HELPER_PATH
that it creates a high system load, or on smaller systems that it creates a high system load, or on smaller systems
it is known to create out-of-memory situations during bootup. it is known to create out-of-memory situations during bootup.
To disable user space helper program execution at early boot config UEVENT_HELPER_PATH
time specify an empty string here. This setting can be altered 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 via /proc/sys/kernel/hotplug or via /sys/kernel/uevent_helper
later at runtime. later at runtime.
......
...@@ -32,8 +32,10 @@ ...@@ -32,8 +32,10 @@
#define UEVENT_NUM_ENVP 32 /* number of env pointers */ #define UEVENT_NUM_ENVP 32 /* number of env pointers */
#define UEVENT_BUFFER_SIZE 2048 /* buffer for the variables */ #define UEVENT_BUFFER_SIZE 2048 /* buffer for the variables */
#ifdef CONFIG_UEVENT_HELPER
/* path to the userspace helper executed on an event */ /* path to the userspace helper executed on an event */
extern char uevent_helper[]; extern char uevent_helper[];
#endif
/* counter to tag the uevent, read only except for the kobject core */ /* counter to tag the uevent, read only except for the kobject core */
extern u64 uevent_seqnum; extern u64 uevent_seqnum;
......
...@@ -37,6 +37,7 @@ static ssize_t uevent_seqnum_show(struct kobject *kobj, ...@@ -37,6 +37,7 @@ static ssize_t uevent_seqnum_show(struct kobject *kobj,
} }
KERNEL_ATTR_RO(uevent_seqnum); KERNEL_ATTR_RO(uevent_seqnum);
#ifdef CONFIG_UEVENT_HELPER
/* uevent helper program, used during early boot */ /* uevent helper program, used during early boot */
static ssize_t uevent_helper_show(struct kobject *kobj, static ssize_t uevent_helper_show(struct kobject *kobj,
struct kobj_attribute *attr, char *buf) struct kobj_attribute *attr, char *buf)
...@@ -56,7 +57,7 @@ static ssize_t uevent_helper_store(struct kobject *kobj, ...@@ -56,7 +57,7 @@ static ssize_t uevent_helper_store(struct kobject *kobj,
return count; return count;
} }
KERNEL_ATTR_RW(uevent_helper); KERNEL_ATTR_RW(uevent_helper);
#endif
#ifdef CONFIG_PROFILING #ifdef CONFIG_PROFILING
static ssize_t profiling_show(struct kobject *kobj, static ssize_t profiling_show(struct kobject *kobj,
...@@ -189,7 +190,9 @@ EXPORT_SYMBOL_GPL(kernel_kobj); ...@@ -189,7 +190,9 @@ EXPORT_SYMBOL_GPL(kernel_kobj);
static struct attribute * kernel_attrs[] = { static struct attribute * kernel_attrs[] = {
&fscaps_attr.attr, &fscaps_attr.attr,
&uevent_seqnum_attr.attr, &uevent_seqnum_attr.attr,
#ifdef CONFIG_UEVENT_HELPER
&uevent_helper_attr.attr, &uevent_helper_attr.attr,
#endif
#ifdef CONFIG_PROFILING #ifdef CONFIG_PROFILING
&profiling_attr.attr, &profiling_attr.attr,
#endif #endif
......
...@@ -643,7 +643,7 @@ static struct ctl_table kern_table[] = { ...@@ -643,7 +643,7 @@ static struct ctl_table kern_table[] = {
.extra2 = &one, .extra2 = &one,
}, },
#endif #endif
#ifdef CONFIG_UEVENT_HELPER
{ {
.procname = "hotplug", .procname = "hotplug",
.data = &uevent_helper, .data = &uevent_helper,
...@@ -651,7 +651,7 @@ static struct ctl_table kern_table[] = { ...@@ -651,7 +651,7 @@ static struct ctl_table kern_table[] = {
.mode = 0644, .mode = 0644,
.proc_handler = proc_dostring, .proc_handler = proc_dostring,
}, },
#endif
#ifdef CONFIG_CHR_DEV_SG #ifdef CONFIG_CHR_DEV_SG
{ {
.procname = "sg-big-buff", .procname = "sg-big-buff",
......
...@@ -29,7 +29,9 @@ ...@@ -29,7 +29,9 @@
u64 uevent_seqnum; u64 uevent_seqnum;
#ifdef CONFIG_UEVENT_HELPER
char uevent_helper[UEVENT_HELPER_PATH_LEN] = CONFIG_UEVENT_HELPER_PATH; char uevent_helper[UEVENT_HELPER_PATH_LEN] = CONFIG_UEVENT_HELPER_PATH;
#endif
#ifdef CONFIG_NET #ifdef CONFIG_NET
struct uevent_sock { struct uevent_sock {
struct list_head list; struct list_head list;
...@@ -109,6 +111,7 @@ static int kobj_bcast_filter(struct sock *dsk, struct sk_buff *skb, void *data) ...@@ -109,6 +111,7 @@ static int kobj_bcast_filter(struct sock *dsk, struct sk_buff *skb, void *data)
} }
#endif #endif
#ifdef CONFIG_UEVENT_HELPER
static int kobj_usermode_filter(struct kobject *kobj) static int kobj_usermode_filter(struct kobject *kobj)
{ {
const struct kobj_ns_type_operations *ops; const struct kobj_ns_type_operations *ops;
...@@ -147,6 +150,7 @@ static void cleanup_uevent_env(struct subprocess_info *info) ...@@ -147,6 +150,7 @@ static void cleanup_uevent_env(struct subprocess_info *info)
{ {
kfree(info->data); kfree(info->data);
} }
#endif
/** /**
* kobject_uevent_env - send an uevent with environmental data * kobject_uevent_env - send an uevent with environmental data
...@@ -323,6 +327,7 @@ int kobject_uevent_env(struct kobject *kobj, enum kobject_action action, ...@@ -323,6 +327,7 @@ int kobject_uevent_env(struct kobject *kobj, enum kobject_action action,
#endif #endif
mutex_unlock(&uevent_sock_mutex); mutex_unlock(&uevent_sock_mutex);
#ifdef CONFIG_UEVENT_HELPER
/* call uevent_helper, usually only enabled during early boot */ /* call uevent_helper, usually only enabled during early boot */
if (uevent_helper[0] && !kobj_usermode_filter(kobj)) { if (uevent_helper[0] && !kobj_usermode_filter(kobj)) {
struct subprocess_info *info; struct subprocess_info *info;
...@@ -347,6 +352,7 @@ int kobject_uevent_env(struct kobject *kobj, enum kobject_action action, ...@@ -347,6 +352,7 @@ int kobject_uevent_env(struct kobject *kobj, enum kobject_action action,
env = NULL; /* freed by cleanup_uevent_env */ env = NULL; /* freed by cleanup_uevent_env */
} }
} }
#endif
exit: exit:
kfree(devpath); kfree(devpath);
......
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