aboutsummaryrefslogtreecommitdiffstats
path: root/kernel/ksysfs.c
blob: cf02d4ba9add26778f43738813c6f76974a132c2 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
/*
 * kernel/ksysfs.c - sysfs attributes in /sys/kernel, which
 * 		     are not related to any other subsystem
 *
 * Copyright (C) 2004 Kay Sievers <kay.sievers@vrfy.org>
 * 
 * This file is release under the GPLv2
 *
 */

#include <linux/kobject.h>
#include <linux/string.h>
#include <linux/sysfs.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/kexec.h>
#include <linux/sched.h>

#define KERNEL_ATTR_RO(_name) \
static struct subsys_attribute _name##_attr = __ATTR_RO(_name)

#define KERNEL_ATTR_RW(_name) \
static struct subsys_attribute _name##_attr = \
	__ATTR(_name, 0644, _name##_show, _name##_store)

#if defined(CONFIG_HOTPLUG) && defined(CONFIG_NET)
/* current uevent sequence number */
static ssize_t uevent_seqnum_show(struct kset *kset, 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 kset *kset, char *page)
{
	return sprintf(page, "%s\n", uevent_helper);
}
static ssize_t uevent_helper_store(struct kset *kset, const char *page, size_t count)
{
	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_RW(uevent_helper);
#endif

#ifdef CONFIG_KEXEC
static ssize_t kexec_loaded_show(struct kset *kset, char *page)
{
	return sprintf(page, "%d\n", !!kexec_image);
}
KERNEL_ATTR_RO(kexec_loaded);

static ssize_t kexec_crash_loaded_show(struct kset *kset, char *page)
{
	return sprintf(page, "%d\n", !!kexec_crash_image);
}
KERNEL_ATTR_RO(kexec_crash_loaded);

static ssize_t vmcoreinfo_show(struct kset *kset, char *page)
{
	return sprintf(page, "%lx %x\n",
		       paddr_vmcoreinfo_note(),
		       (unsigned int)vmcoreinfo_max_size);
}
KERNEL_ATTR_RO(vmcoreinfo);

#endif /* CONFIG_KEXEC */

/*
 * Make /sys/kernel/notes give the raw contents of our kernel .notes section.
 */
extern const void __start_notes __attribute__((weak));
extern const void __stop_notes __attribute__((weak));
#define	notes_size (&__stop_notes - &__start_notes)

static ssize_t notes_read(struct kobject *kobj, struct bin_attribute *bin_attr,
			  char *buf, loff_t off, size_t count)
{
	memcpy(buf, &__start_notes + off, count);
	return count;
}

static struct bin_attribute notes_attr = {
	.attr = {
		.name = "notes",
		.mode = S_IRUGO,
	},
	.read = &notes_read,
};

struct kset *kernel_kset;
EXPORT_SYMBOL_GPL(kernel_kset);

static struct attribute * kernel_attrs[] = {
#if defined(CONFIG_HOTPLUG) && defined(CONFIG_NET)
	&uevent_seqnum_attr.attr,
	&uevent_helper_attr.attr,
#endif
#ifdef CONFIG_KEXEC
	&kexec_loaded_attr.attr,
	&kexec_crash_loaded_attr.attr,
	&vmcoreinfo_attr.attr,
#endif
	NULL
};

static struct attribute_group kernel_attr_group = {
	.attrs = kernel_attrs,
};

static int __init ksysfs_init(void)
{
	int error;

	kernel_kset = kset_create_and_add("kernel", NULL, NULL);
	if (!kernel_kset) {
		error = -ENOMEM;
		goto exit;
	}
	error = sysfs_create_group(&kernel_kset->kobj, &kernel_attr_group);
	if (error)
		goto kset_exit;

	if (notes_size > 0) {
		notes_attr.size = notes_size;
		error = sysfs_create_bin_file(&kernel_kset->kobj, &notes_attr);
		if (error)
			goto group_exit;
	}

	/*
	 * Create "/sys/kernel/uids" directory and corresponding root user's
	 * directory under it.
	 */
	error = uids_kobject_init();
	if (error)
		goto notes_exit;

	return 0;

notes_exit:
	if (notes_size > 0)
		sysfs_remove_bin_file(&kernel_kset->kobj, &notes_attr);
group_exit:
	sysfs_remove_group(&kernel_kset->kobj, &kernel_attr_group);
kset_exit:
	kset_unregister(kernel_kset);
exit:
	return error;
}

core_initcall(ksysfs_init);