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/profile.h>
  18#include <linux/sched.h>
  19
  20#define KERNEL_ATTR_RO(_name) \
  21static struct kobj_attribute _name##_attr = __ATTR_RO(_name)
  22
  23#define KERNEL_ATTR_RW(_name) \
  24static struct kobj_attribute _name##_attr = \
  25        __ATTR(_name, 0644, _name##_show, _name##_store)
  26
  27#if defined(CONFIG_HOTPLUG)
  28/* current uevent sequence number */
  29static ssize_t uevent_seqnum_show(struct kobject *kobj,
  30                                  struct kobj_attribute *attr, char *buf)
  31{
  32        return sprintf(buf, "%llu\n", (unsigned long long)uevent_seqnum);
  33}
  34KERNEL_ATTR_RO(uevent_seqnum);
  35
  36/* uevent helper program, used during early boo */
  37static ssize_t uevent_helper_show(struct kobject *kobj,
  38                                  struct kobj_attribute *attr, char *buf)
  39{
  40        return sprintf(buf, "%s\n", uevent_helper);
  41}
  42static ssize_t uevent_helper_store(struct kobject *kobj,
  43                                   struct kobj_attribute *attr,
  44                                   const char *buf, size_t count)
  45{
  46        if (count+1 > UEVENT_HELPER_PATH_LEN)
  47                return -ENOENT;
  48        memcpy(uevent_helper, buf, count);
  49        uevent_helper[count] = '\0';
  50        if (count && uevent_helper[count-1] == '\n')
  51                uevent_helper[count-1] = '\0';
  52        return count;
  53}
  54KERNEL_ATTR_RW(uevent_helper);
  55#endif
  56
  57#ifdef CONFIG_PROFILING
  58static ssize_t profiling_show(struct kobject *kobj,
  59                                  struct kobj_attribute *attr, char *buf)
  60{
  61        return sprintf(buf, "%d\n", prof_on);
  62}
  63static ssize_t profiling_store(struct kobject *kobj,
  64                                   struct kobj_attribute *attr,
  65                                   const char *buf, size_t count)
  66{
  67        int ret;
  68
  69        if (prof_on)
  70                return -EEXIST;
  71        /*
  72         * This eventually calls into get_option() which
  73         * has a ton of callers and is not const.  It is
  74         * easiest to cast it away here.
  75         */
  76        profile_setup((char *)buf);
  77        ret = profile_init();
  78        if (ret)
  79                return ret;
  80        ret = create_proc_profile();
  81        if (ret)
  82                return ret;
  83        return count;
  84}
  85KERNEL_ATTR_RW(profiling);
  86#endif
  87
  88#ifdef CONFIG_KEXEC
  89static ssize_t kexec_loaded_show(struct kobject *kobj,
  90                                 struct kobj_attribute *attr, char *buf)
  91{
  92        return sprintf(buf, "%d\n", !!kexec_image);
  93}
  94KERNEL_ATTR_RO(kexec_loaded);
  95
  96static ssize_t kexec_crash_loaded_show(struct kobject *kobj,
  97                                       struct kobj_attribute *attr, char *buf)
  98{
  99        return sprintf(buf, "%d\n", !!kexec_crash_image);
 100}
 101KERNEL_ATTR_RO(kexec_crash_loaded);
 102
 103static ssize_t vmcoreinfo_show(struct kobject *kobj,
 104                               struct kobj_attribute *attr, char *buf)
 105{
 106        return sprintf(buf, "%lx %x\n",
 107                       paddr_vmcoreinfo_note(),
 108                       (unsigned int)vmcoreinfo_max_size);
 109}
 110KERNEL_ATTR_RO(vmcoreinfo);
 111
 112#endif /* CONFIG_KEXEC */
 113
 114/*
 115 * Make /sys/kernel/notes give the raw contents of our kernel .notes section.
 116 */
 117extern const void __start_notes __attribute__((weak));
 118extern const void __stop_notes __attribute__((weak));
 119#define notes_size (&__stop_notes - &__start_notes)
 120
 121static ssize_t notes_read(struct kobject *kobj, struct bin_attribute *bin_attr,
 122                          char *buf, loff_t off, size_t count)
 123{
 124        memcpy(buf, &__start_notes + off, count);
 125        return count;
 126}
 127
 128static struct bin_attribute notes_attr = {
 129        .attr = {
 130                .name = "notes",
 131                .mode = S_IRUGO,
 132        },
 133        .read = &notes_read,
 134};
 135
 136struct kobject *kernel_kobj;
 137EXPORT_SYMBOL_GPL(kernel_kobj);
 138
 139static struct attribute * kernel_attrs[] = {
 140#if defined(CONFIG_HOTPLUG)
 141        &uevent_seqnum_attr.attr,
 142        &uevent_helper_attr.attr,
 143#endif
 144#ifdef CONFIG_PROFILING
 145        &profiling_attr.attr,
 146#endif
 147#ifdef CONFIG_KEXEC
 148        &kexec_loaded_attr.attr,
 149        &kexec_crash_loaded_attr.attr,
 150        &vmcoreinfo_attr.attr,
 151#endif
 152        NULL
 153};
 154
 155static struct attribute_group kernel_attr_group = {
 156        .attrs = kernel_attrs,
 157};
 158
 159static int __init ksysfs_init(void)
 160{
 161        int error;
 162
 163        kernel_kobj = kobject_create_and_add("kernel", NULL);
 164        if (!kernel_kobj) {
 165                error = -ENOMEM;
 166                goto exit;
 167        }
 168        error = sysfs_create_group(kernel_kobj, &kernel_attr_group);
 169        if (error)
 170                goto kset_exit;
 171
 172        if (notes_size > 0) {
 173                notes_attr.size = notes_size;
 174                error = sysfs_create_bin_file(kernel_kobj, &notes_attr);
 175                if (error)
 176                        goto group_exit;
 177        }
 178
 179        /* create the /sys/kernel/uids/ directory */
 180        error = uids_sysfs_init();
 181        if (error)
 182                goto notes_exit;
 183
 184        return 0;
 185
 186notes_exit:
 187        if (notes_size > 0)
 188                sysfs_remove_bin_file(kernel_kobj, &notes_attr);
 189group_exit:
 190        sysfs_remove_group(kernel_kobj, &kernel_attr_group);
 191kset_exit:
 192        kobject_put(kernel_kobj);
 193exit:
 194        return error;
 195}
 196
 197core_initcall(ksysfs_init);
 198