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-rw-r--r--kernel/ksysfs.c30
1 files changed, 26 insertions, 4 deletions
diff --git a/kernel/ksysfs.c b/kernel/ksysfs.c
index 015fb69ad94d..99af8b05eeaa 100644
--- a/kernel/ksysfs.c
+++ b/kernel/ksysfs.c
@@ -15,6 +15,9 @@
#include <linux/module.h>
#include <linux/init.h>
+u64 uevent_seqnum;
+char uevent_helper[UEVENT_HELPER_PATH_LEN] = "/sbin/hotplug";
+
#define KERNEL_ATTR_RO(_name) \
static struct subsys_attribute _name##_attr = __ATTR_RO(_name)
@@ -23,11 +26,29 @@ static struct subsys_attribute _name##_attr = \
__ATTR(_name, 0644, _name##_show, _name##_store)
#ifdef CONFIG_HOTPLUG
-static ssize_t hotplug_seqnum_show(struct subsystem *subsys, char *page)
+/* current uevent sequence number */
+static ssize_t uevent_seqnum_show(struct subsystem *subsys, char *page)
+{
+ return sprintf(page, "%llu\n", (unsigned long long)uevent_seqnum);
+}
+KERNEL_ATTR_RO(uevent_seqnum);
+
+/* uevent helper program, used during early boo */
+static ssize_t uevent_helper_show(struct subsystem *subsys, char *page)
+{
+ return sprintf(page, "%s\n", uevent_helper);
+}
+static ssize_t uevent_helper_store(struct subsystem *subsys, const char *page, size_t count)
{
- return sprintf(page, "%llu\n", (unsigned long long)hotplug_seqnum);
+ if (count+1 > UEVENT_HELPER_PATH_LEN)
+ return -ENOENT;
+ memcpy(uevent_helper, page, count);
+ uevent_helper[count] = '\0';
+ if (count && uevent_helper[count-1] == '\n')
+ uevent_helper[count-1] = '\0';
+ return count;
}
-KERNEL_ATTR_RO(hotplug_seqnum);
+KERNEL_ATTR_RW(uevent_helper);
#endif
#ifdef CONFIG_KEXEC
@@ -45,7 +66,8 @@ EXPORT_SYMBOL_GPL(kernel_subsys);
static struct attribute * kernel_attrs[] = {
#ifdef CONFIG_HOTPLUG
- &hotplug_seqnum_attr.attr,
+ &uevent_seqnum_attr.attr,
+ &uevent_helper_attr.attr,
#endif
#ifdef CONFIG_KEXEC
&crash_notes_attr.attr,