From 86d56134f1b67d0c18025ba5cade95c048ed528d Mon Sep 17 00:00:00 2001 From: Michael Marineau Date: Thu, 10 Apr 2014 14:09:31 -0700 Subject: [PATCH] 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: Darren Shepherd Signed-off-by: Michael Marineau Signed-off-by: Greg Kroah-Hartman --- drivers/base/Kconfig | 17 +++++++++++------ include/linux/kobject.h | 2 ++ kernel/ksysfs.c | 5 ++++- kernel/sysctl.c | 4 ++-- lib/kobject_uevent.c | 6 ++++++ 5 files changed, 25 insertions(+), 9 deletions(-) diff --git a/drivers/base/Kconfig b/drivers/base/Kconfig index 8fa8deab6449..4b7b4522b64f 100644 --- a/drivers/base/Kconfig +++ b/drivers/base/Kconfig @@ -1,10 +1,10 @@ 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. diff --git a/include/linux/kobject.h b/include/linux/kobject.h index f896a33e8341..2d61b909f414 100644 --- a/include/linux/kobject.h +++ b/include/linux/kobject.h @@ -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; diff --git a/kernel/ksysfs.c b/kernel/ksysfs.c index 2495a9b14ac8..6683ccef9fff 100644 --- a/kernel/ksysfs.c +++ b/kernel/ksysfs.c @@ -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 diff --git a/kernel/sysctl.c b/kernel/sysctl.c index 74f5b580fe34..bc966a8ffc3e 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -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", diff --git a/lib/kobject_uevent.c b/lib/kobject_uevent.c index 4e3bd71bd949..9ebf9e20de53 100644 --- a/lib/kobject_uevent.c +++ b/lib/kobject_uevent.c @@ -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); -- 2.39.2