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eac531c @gokhanmoral test commit
authored Mar 22, 2012
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 #include <linux/capability.h>
20
21 #define KERNEL_ATTR_RO(_name) \
22 static struct kobj_attribute _name##_attr = __ATTR_RO(_name)
23
24 #define KERNEL_ATTR_RW(_name) \
25 static struct kobj_attribute _name##_attr = \
26 __ATTR(_name, 0644, _name##_show, _name##_store)
27
28 #if defined(CONFIG_HOTPLUG)
29 /* current uevent sequence number */
30 static ssize_t uevent_seqnum_show(struct kobject *kobj,
31 struct kobj_attribute *attr, char *buf)
32 {
33 return sprintf(buf, "%llu\n", (unsigned long long)uevent_seqnum);
34 }
35 KERNEL_ATTR_RO(uevent_seqnum);
36
37 /* uevent helper program, used during early boot */
38 static ssize_t uevent_helper_show(struct kobject *kobj,
39 struct kobj_attribute *attr, char *buf)
40 {
41 return sprintf(buf, "%s\n", uevent_helper);
42 }
43 static ssize_t uevent_helper_store(struct kobject *kobj,
44 struct kobj_attribute *attr,
45 const char *buf, size_t count)
46 {
47 if (count+1 > UEVENT_HELPER_PATH_LEN)
48 return -ENOENT;
49 memcpy(uevent_helper, buf, count);
50 uevent_helper[count] = '\0';
51 if (count && uevent_helper[count-1] == '\n')
52 uevent_helper[count-1] = '\0';
53 return count;
54 }
55 KERNEL_ATTR_RW(uevent_helper);
56 #endif
57
58 #ifdef CONFIG_PROFILING
59 static ssize_t profiling_show(struct kobject *kobj,
60 struct kobj_attribute *attr, char *buf)
61 {
62 return sprintf(buf, "%d\n", prof_on);
63 }
64 static ssize_t profiling_store(struct kobject *kobj,
65 struct kobj_attribute *attr,
66 const char *buf, size_t count)
67 {
68 int ret;
69
70 if (prof_on)
71 return -EEXIST;
72 /*
73 * This eventually calls into get_option() which
74 * has a ton of callers and is not const. It is
75 * easiest to cast it away here.
76 */
77 profile_setup((char *)buf);
78 ret = profile_init();
79 if (ret)
80 return ret;
81 ret = create_proc_profile();
82 if (ret)
83 return ret;
84 return count;
85 }
86 KERNEL_ATTR_RW(profiling);
87 #endif
88
89 #ifdef CONFIG_KEXEC
90 static ssize_t kexec_loaded_show(struct kobject *kobj,
91 struct kobj_attribute *attr, char *buf)
92 {
93 return sprintf(buf, "%d\n", !!kexec_image);
94 }
95 KERNEL_ATTR_RO(kexec_loaded);
96
97 static ssize_t kexec_crash_loaded_show(struct kobject *kobj,
98 struct kobj_attribute *attr, char *buf)
99 {
100 return sprintf(buf, "%d\n", !!kexec_crash_image);
101 }
102 KERNEL_ATTR_RO(kexec_crash_loaded);
103
104 static ssize_t kexec_crash_size_show(struct kobject *kobj,
105 struct kobj_attribute *attr, char *buf)
106 {
107 return sprintf(buf, "%zu\n", crash_get_memory_size());
108 }
109 static ssize_t kexec_crash_size_store(struct kobject *kobj,
110 struct kobj_attribute *attr,
111 const char *buf, size_t count)
112 {
113 unsigned long cnt;
114 int ret;
115
116 if (strict_strtoul(buf, 0, &cnt))
117 return -EINVAL;
118
119 ret = crash_shrink_memory(cnt);
120 return ret < 0 ? ret : count;
121 }
122 KERNEL_ATTR_RW(kexec_crash_size);
123
124 static ssize_t vmcoreinfo_show(struct kobject *kobj,
125 struct kobj_attribute *attr, char *buf)
126 {
127 return sprintf(buf, "%lx %x\n",
128 paddr_vmcoreinfo_note(),
129 (unsigned int)vmcoreinfo_max_size);
130 }
131 KERNEL_ATTR_RO(vmcoreinfo);
132
133 #endif /* CONFIG_KEXEC */
134
135 /* whether file capabilities are enabled */
136 static ssize_t fscaps_show(struct kobject *kobj,
137 struct kobj_attribute *attr, char *buf)
138 {
139 return sprintf(buf, "%d\n", file_caps_enabled);
140 }
141 KERNEL_ATTR_RO(fscaps);
142
143 /*
144 * Make /sys/kernel/notes give the raw contents of our kernel .notes section.
145 */
146 extern const void __start_notes __attribute__((weak));
147 extern const void __stop_notes __attribute__((weak));
148 #define notes_size (&__stop_notes - &__start_notes)
149
150 static ssize_t notes_read(struct file *filp, struct kobject *kobj,
151 struct bin_attribute *bin_attr,
152 char *buf, loff_t off, size_t count)
153 {
154 memcpy(buf, &__start_notes + off, count);
155 return count;
156 }
157
158 static struct bin_attribute notes_attr = {
159 .attr = {
160 .name = "notes",
161 .mode = S_IRUGO,
162 },
163 .read = &notes_read,
164 };
165
166 struct kobject *kernel_kobj;
167 EXPORT_SYMBOL_GPL(kernel_kobj);
168
169 static struct attribute * kernel_attrs[] = {
170 &fscaps_attr.attr,
171 #if defined(CONFIG_HOTPLUG)
172 &uevent_seqnum_attr.attr,
173 &uevent_helper_attr.attr,
174 #endif
175 #ifdef CONFIG_PROFILING
176 &profiling_attr.attr,
177 #endif
178 #ifdef CONFIG_KEXEC
179 &kexec_loaded_attr.attr,
180 &kexec_crash_loaded_attr.attr,
181 &kexec_crash_size_attr.attr,
182 &vmcoreinfo_attr.attr,
183 #endif
184 NULL
185 };
186
187 static struct attribute_group kernel_attr_group = {
188 .attrs = kernel_attrs,
189 };
190
191 static int __init ksysfs_init(void)
192 {
193 int error;
194
195 kernel_kobj = kobject_create_and_add("kernel", NULL);
196 if (!kernel_kobj) {
197 error = -ENOMEM;
198 goto exit;
199 }
200 error = sysfs_create_group(kernel_kobj, &kernel_attr_group);
201 if (error)
202 goto kset_exit;
203
204 if (notes_size > 0) {
205 notes_attr.size = notes_size;
206 error = sysfs_create_bin_file(kernel_kobj, &notes_attr);
207 if (error)
208 goto group_exit;
209 }
210
211 return 0;
212
213 group_exit:
214 sysfs_remove_group(kernel_kobj, &kernel_attr_group);
215 kset_exit:
216 kobject_put(kernel_kobj);
217 exit:
218 return error;
219 }
220
221 core_initcall(ksysfs_init);
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