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) \
 21 static struct kobj_attribute _name##_attr = __ATTR_RO(_name)
 22 
 23 #define KERNEL_ATTR_RW(_name) \
 24 static struct kobj_attribute _name##_attr = \
 25         __ATTR(_name, 0644, _name##_show, _name##_store)
 26 
 27 #if defined(CONFIG_HOTPLUG) && defined(CONFIG_NET)
 28 /* current uevent sequence number */
 29 static 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 }
 34 KERNEL_ATTR_RO(uevent_seqnum);
 35 
 36 /* uevent helper program, used during early boo */
 37 static 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 }
 42 static 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 }
 54 KERNEL_ATTR_RW(uevent_helper);
 55 #endif
 56 
 57 #ifdef CONFIG_PROFILING
 58 static ssize_t profiling_show(struct kobject *kobj,
 59                                   struct kobj_attribute *attr, char *buf)
 60 {
 61         return sprintf(buf, "%d\n", prof_on);
 62 }
 63 static 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 }
 85 KERNEL_ATTR_RW(profiling);
 86 #endif
 87 
 88 #ifdef CONFIG_KEXEC
 89 static 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 }
 94 KERNEL_ATTR_RO(kexec_loaded);
 95 
 96 static 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 }
101 KERNEL_ATTR_RO(kexec_crash_loaded);
102 
103 static 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 }
110 KERNEL_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  */
117 extern const void __start_notes __attribute__((weak));
118 extern const void __stop_notes __attribute__((weak));
119 #define notes_size (&__stop_notes - &__start_notes)
120 
121 static 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 
128 static struct bin_attribute notes_attr = {
129         .attr = {
130                 .name = "notes",
131                 .mode = S_IRUGO,
132         },
133         .read = &notes_read,
134 };
135 
136 struct kobject *kernel_kobj;
137 EXPORT_SYMBOL_GPL(kernel_kobj);
138 
139 static struct attribute * kernel_attrs[] = {
140 #if defined(CONFIG_HOTPLUG) && defined(CONFIG_NET)
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 
155 static struct attribute_group kernel_attr_group = {
156         .attrs = kernel_attrs,
157 };
158 
159 static 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 
186 notes_exit:
187         if (notes_size > 0)
188                 sysfs_remove_bin_file(kernel_kobj, &notes_attr);
189 group_exit:
190         sysfs_remove_group(kernel_kobj, &kernel_attr_group);
191 kset_exit:
192         kobject_put(kernel_kobj);
193 exit:
194         return error;
195 }
196 
197 core_initcall(ksysfs_init);
198
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Linux/kernel/ksysfs.c
