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/sched.h> 18 19 #define KERNEL_ATTR_RO(_name) \ 20 static struct kobj_attribute _name##_attr = __ATTR_RO(_name) 21 22 #define KERNEL_ATTR_RW(_name) \ 23 static struct kobj_attribute _name##_attr = \ 24 __ATTR(_name, 0644, _name##_show, _name##_store) 25 26 #if defined(CONFIG_HOTPLUG) && defined(CONFIG_NET) 27 /* current uevent sequence number */ 28 static ssize_t uevent_seqnum_show(struct kobject *kobj, 29 struct kobj_attribute *attr, char *buf) 30 { 31 return sprintf(buf, "%llu\n", (unsigned long long)uevent_seqnum); 32 } 33 KERNEL_ATTR_RO(uevent_seqnum); 34 35 /* uevent helper program, used during early boo */ 36 static ssize_t uevent_helper_show(struct kobject *kobj, 37 struct kobj_attribute *attr, char *buf) 38 { 39 return sprintf(buf, "%s\n", uevent_helper); 40 } 41 static ssize_t uevent_helper_store(struct kobject *kobj, 42 struct kobj_attribute *attr, 43 const char *buf, size_t count) 44 { 45 if (count+1 > UEVENT_HELPER_PATH_LEN) 46 return -ENOENT; 47 memcpy(uevent_helper, buf, count); 48 uevent_helper[count] = '\0'; 49 if (count && uevent_helper[count-1] == '\n') 50 uevent_helper[count-1] = '\0'; 51 return count; 52 } 53 KERNEL_ATTR_RW(uevent_helper); 54 #endif 55 56 #ifdef CONFIG_KEXEC 57 static ssize_t kexec_loaded_show(struct kobject *kobj, 58 struct kobj_attribute *attr, char *buf) 59 { 60 return sprintf(buf, "%d\n", !!kexec_image); 61 } 62 KERNEL_ATTR_RO(kexec_loaded); 63 64 static ssize_t kexec_crash_loaded_show(struct kobject *kobj, 65 struct kobj_attribute *attr, char *buf) 66 { 67 return sprintf(buf, "%d\n", !!kexec_crash_image); 68 } 69 KERNEL_ATTR_RO(kexec_crash_loaded); 70 71 static ssize_t vmcoreinfo_show(struct kobject *kobj, 72 struct kobj_attribute *attr, char *buf) 73 { 74 return sprintf(buf, "%lx %x\n", 75 paddr_vmcoreinfo_note(), 76 (unsigned int)vmcoreinfo_max_size); 77 } 78 KERNEL_ATTR_RO(vmcoreinfo); 79 80 #endif /* CONFIG_KEXEC */ 81 82 /* 83 * Make /sys/kernel/notes give the raw contents of our kernel .notes section. 84 */ 85 extern const void __start_notes __attribute__((weak)); 86 extern const void __stop_notes __attribute__((weak)); 87 #define notes_size (&__stop_notes - &__start_notes) 88 89 static ssize_t notes_read(struct kobject *kobj, struct bin_attribute *bin_attr, 90 char *buf, loff_t off, size_t count) 91 { 92 memcpy(buf, &__start_notes + off, count); 93 return count; 94 } 95 96 static struct bin_attribute notes_attr = { 97 .attr = { 98 .name = "notes", 99 .mode = S_IRUGO, 100 }, 101 .read = ¬es_read, 102 }; 103 104 struct kobject *kernel_kobj; 105 EXPORT_SYMBOL_GPL(kernel_kobj); 106 107 static struct attribute * kernel_attrs[] = { 108 #if defined(CONFIG_HOTPLUG) && defined(CONFIG_NET) 109 &uevent_seqnum_attr.attr, 110 &uevent_helper_attr.attr, 111 #endif 112 #ifdef CONFIG_KEXEC 113 &kexec_loaded_attr.attr, 114 &kexec_crash_loaded_attr.attr, 115 &vmcoreinfo_attr.attr, 116 #endif 117 NULL 118 }; 119 120 static struct attribute_group kernel_attr_group = { 121 .attrs = kernel_attrs, 122 }; 123 124 static int __init ksysfs_init(void) 125 { 126 int error; 127 128 kernel_kobj = kobject_create_and_add("kernel", NULL); 129 if (!kernel_kobj) { 130 error = -ENOMEM; 131 goto exit; 132 } 133 error = sysfs_create_group(kernel_kobj, &kernel_attr_group); 134 if (error) 135 goto kset_exit; 136 137 if (notes_size > 0) { 138 notes_attr.size = notes_size; 139 error = sysfs_create_bin_file(kernel_kobj, ¬es_attr); 140 if (error) 141 goto group_exit; 142 } 143 144 /* create the /sys/kernel/uids/ directory */ 145 error = uids_sysfs_init(); 146 if (error) 147 goto notes_exit; 148 149 return 0; 150 151 notes_exit: 152 if (notes_size > 0) 153 sysfs_remove_bin_file(kernel_kobj, ¬es_attr); 154 group_exit: 155 sysfs_remove_group(kernel_kobj, &kernel_attr_group); 156 kset_exit: 157 kobject_put(kernel_kobj); 158 exit: 159 return error; 160 } 161 162 core_initcall(ksysfs_init); 163