LXR linux/kernel/ksysfs.c

   1/*
   2 * kernel/ksysfs.c - sysfs attributes in /sys/kernel, which
   3 *                   are not related to any other subsystem
   4 *
   5 * Copyright (C) 2004 Kay Sievers <kay.sievers@vrfy.org>
   6 * 
   7 * This file is release under the GPLv2
   8 *
   9 */
  10
  11#include <linux/kobject.h>
  12#include <linux/string.h>
  13#include <linux/sysfs.h>
  14#include <linux/module.h>
  15#include <linux/init.h>
  16#include <linux/kexec.h>
  17#include <linux/sched.h>
  18
  19#define KERNEL_ATTR_RO(_name) \
  20static struct kobj_attribute _name##_attr = __ATTR_RO(_name)
  21
  22#define KERNEL_ATTR_RW(_name) \
  23static struct kobj_attribute _name##_attr = \
  24        __ATTR(_name, 0644, _name##_show, _name##_store)
  25
  26#if defined(CONFIG_HOTPLUG) && defined(CONFIG_NET)
  27/* current uevent sequence number */
  28static ssize_t uevent_seqnum_show(struct kobject *kobj,
  29                                  struct kobj_attribute *attr, char *buf)
  30{
  31        return sprintf(buf, "%llu\n", (unsigned long long)uevent_seqnum);
  32}
  33KERNEL_ATTR_RO(uevent_seqnum);
  34
  35/* uevent helper program, used during early boo */
  36static ssize_t uevent_helper_show(struct kobject *kobj,
  37                                  struct kobj_attribute *attr, char *buf)
  38{
  39        return sprintf(buf, "%s\n", uevent_helper);
  40}
  41static ssize_t uevent_helper_store(struct kobject *kobj,
  42                                   struct kobj_attribute *attr,
  43                                   const char *buf, size_t count)
  44{
  45        if (count+1 > UEVENT_HELPER_PATH_LEN)
  46                return -ENOENT;
  47        memcpy(uevent_helper, buf, count);
  48        uevent_helper[count] = '\0';
  49        if (count && uevent_helper[count-1] == '\n')
  50                uevent_helper[count-1] = '\0';
  51        return count;
  52}
  53KERNEL_ATTR_RW(uevent_helper);
  54#endif
  55
  56#ifdef CONFIG_KEXEC
  57static ssize_t kexec_loaded_show(struct kobject *kobj,
  58                                 struct kobj_attribute *attr, char *buf)
  59{
  60        return sprintf(buf, "%d\n", !!kexec_image);
  61}
  62KERNEL_ATTR_RO(kexec_loaded);
  63
  64static ssize_t kexec_crash_loaded_show(struct kobject *kobj,
  65                                       struct kobj_attribute *attr, char *buf)
  66{
  67        return sprintf(buf, "%d\n", !!kexec_crash_image);
  68}
  69KERNEL_ATTR_RO(kexec_crash_loaded);
  70
  71static ssize_t vmcoreinfo_show(struct kobject *kobj,
  72                               struct kobj_attribute *attr, char *buf)
  73{
  74        return sprintf(buf, "%lx %x\n",
  75                       paddr_vmcoreinfo_note(),
  76                       (unsigned int)vmcoreinfo_max_size);
  77}
  78KERNEL_ATTR_RO(vmcoreinfo);
  79
  80#endif /* CONFIG_KEXEC */
  81
  82/*
  83 * Make /sys/kernel/notes give the raw contents of our kernel .notes section.
  84 */
  85extern const void __start_notes __attribute__((weak));
  86extern const void __stop_notes __attribute__((weak));
  87#define notes_size (&__stop_notes - &__start_notes)
  88
  89static ssize_t notes_read(struct kobject *kobj, struct bin_attribute *bin_attr,
  90                          char *buf, loff_t off, size_t count)
  91{
  92        memcpy(buf, &__start_notes + off, count);
  93        return count;
  94}
  95
  96static struct bin_attribute notes_attr = {
  97        .attr = {
  98                .name = "notes",
  99                .mode = S_IRUGO,
 100        },
 101        .read = &notes_read,
 102};
 103
 104struct kobject *kernel_kobj;
 105EXPORT_SYMBOL_GPL(kernel_kobj);
 106
 107static struct attribute * kernel_attrs[] = {
 108#if defined(CONFIG_HOTPLUG) && defined(CONFIG_NET)
 109        &uevent_seqnum_attr.attr,
 110        &uevent_helper_attr.attr,
 111#endif
 112#ifdef CONFIG_KEXEC
 113        &kexec_loaded_attr.attr,
 114        &kexec_crash_loaded_attr.attr,
 115        &vmcoreinfo_attr.attr,
 116#endif
 117        NULL
 118};
 119
 120static struct attribute_group kernel_attr_group = {
 121        .attrs = kernel_attrs,
 122};
 123
 124static int __init ksysfs_init(void)
 125{
 126        int error;
 127
 128        kernel_kobj = kobject_create_and_add("kernel", NULL);
 129        if (!kernel_kobj) {
 130                error = -ENOMEM;
 131                goto exit;
 132        }
 133        error = sysfs_create_group(kernel_kobj, &kernel_attr_group);
 134        if (error)
 135                goto kset_exit;
 136
 137        if (notes_size > 0) {
 138                notes_attr.size = notes_size;
 139                error = sysfs_create_bin_file(kernel_kobj, &notes_attr);
 140                if (error)
 141                        goto group_exit;
 142        }
 143
 144        /* create the /sys/kernel/uids/ directory */
 145        error = uids_sysfs_init();
 146        if (error)
 147                goto notes_exit;
 148
 149        return 0;
 150
 151notes_exit:
 152        if (notes_size > 0)
 153                sysfs_remove_bin_file(kernel_kobj, &notes_attr);
 154group_exit:
 155        sysfs_remove_group(kernel_kobj, &kernel_attr_group);
 156kset_exit:
 157        kobject_put(kernel_kobj);
 158exit:
 159        return error;
 160}
 161
 162core_initcall(ksysfs_init);
 163