seccomp: Refactor the filter callback and the API
[pandora-kernel.git] / 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/export.h>
15 #include <linux/init.h>
16 #include <linux/kexec.h>
17 #include <linux/profile.h>
18 #include <linux/stat.h>
19 #include <linux/sched.h>
20 #include <linux/capability.h>
21 #include <linux/compiler.h>
22
23 #include <linux/rcupdate.h>     /* rcu_expedited */
24
25 #define KERNEL_ATTR_RO(_name) \
26 static struct kobj_attribute _name##_attr = __ATTR_RO(_name)
27
28 #define KERNEL_ATTR_RW(_name) \
29 static struct kobj_attribute _name##_attr = \
30         __ATTR(_name, 0644, _name##_show, _name##_store)
31
32 /* current uevent sequence number */
33 static ssize_t uevent_seqnum_show(struct kobject *kobj,
34                                   struct kobj_attribute *attr, char *buf)
35 {
36         return sprintf(buf, "%llu\n", (unsigned long long)uevent_seqnum);
37 }
38 KERNEL_ATTR_RO(uevent_seqnum);
39
40 #ifdef CONFIG_UEVENT_HELPER
41 /* uevent helper program, used during early boot */
42 static ssize_t uevent_helper_show(struct kobject *kobj,
43                                   struct kobj_attribute *attr, char *buf)
44 {
45         return sprintf(buf, "%s\n", uevent_helper);
46 }
47 static ssize_t uevent_helper_store(struct kobject *kobj,
48                                    struct kobj_attribute *attr,
49                                    const char *buf, size_t count)
50 {
51         if (count+1 > UEVENT_HELPER_PATH_LEN)
52                 return -ENOENT;
53         memcpy(uevent_helper, buf, count);
54         uevent_helper[count] = '\0';
55         if (count && uevent_helper[count-1] == '\n')
56                 uevent_helper[count-1] = '\0';
57         return count;
58 }
59 KERNEL_ATTR_RW(uevent_helper);
60 #endif
61
62 #ifdef CONFIG_PROFILING
63 static ssize_t profiling_show(struct kobject *kobj,
64                                   struct kobj_attribute *attr, char *buf)
65 {
66         return sprintf(buf, "%d\n", prof_on);
67 }
68 static ssize_t profiling_store(struct kobject *kobj,
69                                    struct kobj_attribute *attr,
70                                    const char *buf, size_t count)
71 {
72         int ret;
73
74         if (prof_on)
75                 return -EEXIST;
76         /*
77          * This eventually calls into get_option() which
78          * has a ton of callers and is not const.  It is
79          * easiest to cast it away here.
80          */
81         profile_setup((char *)buf);
82         ret = profile_init();
83         if (ret)
84                 return ret;
85         ret = create_proc_profile();
86         if (ret)
87                 return ret;
88         return count;
89 }
90 KERNEL_ATTR_RW(profiling);
91 #endif
92
93 #ifdef CONFIG_KEXEC
94 static ssize_t kexec_loaded_show(struct kobject *kobj,
95                                  struct kobj_attribute *attr, char *buf)
96 {
97         return sprintf(buf, "%d\n", !!kexec_image);
98 }
99 KERNEL_ATTR_RO(kexec_loaded);
100
101 static ssize_t kexec_crash_loaded_show(struct kobject *kobj,
102                                        struct kobj_attribute *attr, char *buf)
103 {
104         return sprintf(buf, "%d\n", !!kexec_crash_image);
105 }
106 KERNEL_ATTR_RO(kexec_crash_loaded);
107
108 static ssize_t kexec_crash_size_show(struct kobject *kobj,
109                                        struct kobj_attribute *attr, char *buf)
110 {
111         return sprintf(buf, "%zu\n", crash_get_memory_size());
112 }
113 static ssize_t kexec_crash_size_store(struct kobject *kobj,
114                                    struct kobj_attribute *attr,
115                                    const char *buf, size_t count)
116 {
117         unsigned long cnt;
118         int ret;
119
120         if (kstrtoul(buf, 0, &cnt))
121                 return -EINVAL;
122
123         ret = crash_shrink_memory(cnt);
124         return ret < 0 ? ret : count;
125 }
126 KERNEL_ATTR_RW(kexec_crash_size);
127
128 static ssize_t vmcoreinfo_show(struct kobject *kobj,
129                                struct kobj_attribute *attr, char *buf)
130 {
131         return sprintf(buf, "%lx %x\n",
132                        paddr_vmcoreinfo_note(),
133                        (unsigned int)sizeof(vmcoreinfo_note));
134 }
135 KERNEL_ATTR_RO(vmcoreinfo);
136
137 #endif /* CONFIG_KEXEC */
138
139 /* whether file capabilities are enabled */
140 static ssize_t fscaps_show(struct kobject *kobj,
141                                   struct kobj_attribute *attr, char *buf)
142 {
143         return sprintf(buf, "%d\n", file_caps_enabled);
144 }
145 KERNEL_ATTR_RO(fscaps);
146
147 int rcu_expedited;
148 static ssize_t rcu_expedited_show(struct kobject *kobj,
149                                   struct kobj_attribute *attr, char *buf)
150 {
151         return sprintf(buf, "%d\n", rcu_expedited);
152 }
153 static ssize_t rcu_expedited_store(struct kobject *kobj,
154                                    struct kobj_attribute *attr,
155                                    const char *buf, size_t count)
156 {
157         if (kstrtoint(buf, 0, &rcu_expedited))
158                 return -EINVAL;
159
160         return count;
161 }
162 KERNEL_ATTR_RW(rcu_expedited);
163
164 /*
165  * Make /sys/kernel/notes give the raw contents of our kernel .notes section.
166  */
167 extern const void __start_notes __weak;
168 extern const void __stop_notes __weak;
169 #define notes_size (&__stop_notes - &__start_notes)
170
171 static ssize_t notes_read(struct file *filp, struct kobject *kobj,
172                           struct bin_attribute *bin_attr,
173                           char *buf, loff_t off, size_t count)
174 {
175         memcpy(buf, &__start_notes + off, count);
176         return count;
177 }
178
179 static struct bin_attribute notes_attr = {
180         .attr = {
181                 .name = "notes",
182                 .mode = S_IRUGO,
183         },
184         .read = &notes_read,
185 };
186
187 struct kobject *kernel_kobj;
188 EXPORT_SYMBOL_GPL(kernel_kobj);
189
190 static struct attribute * kernel_attrs[] = {
191         &fscaps_attr.attr,
192         &uevent_seqnum_attr.attr,
193 #ifdef CONFIG_UEVENT_HELPER
194         &uevent_helper_attr.attr,
195 #endif
196 #ifdef CONFIG_PROFILING
197         &profiling_attr.attr,
198 #endif
199 #ifdef CONFIG_KEXEC
200         &kexec_loaded_attr.attr,
201         &kexec_crash_loaded_attr.attr,
202         &kexec_crash_size_attr.attr,
203         &vmcoreinfo_attr.attr,
204 #endif
205         &rcu_expedited_attr.attr,
206         NULL
207 };
208
209 static struct attribute_group kernel_attr_group = {
210         .attrs = kernel_attrs,
211 };
212
213 static int __init ksysfs_init(void)
214 {
215         int error;
216
217         kernel_kobj = kobject_create_and_add("kernel", NULL);
218         if (!kernel_kobj) {
219                 error = -ENOMEM;
220                 goto exit;
221         }
222         error = sysfs_create_group(kernel_kobj, &kernel_attr_group);
223         if (error)
224                 goto kset_exit;
225
226         if (notes_size > 0) {
227                 notes_attr.size = notes_size;
228                 error = sysfs_create_bin_file(kernel_kobj, &notes_attr);
229                 if (error)
230                         goto group_exit;
231         }
232
233         return 0;
234
235 group_exit:
236         sysfs_remove_group(kernel_kobj, &kernel_attr_group);
237 kset_exit:
238         kobject_put(kernel_kobj);
239 exit:
240         return error;
241 }
242
243 core_initcall(ksysfs_init);