1 /* 2 * linux/fs/proc/root.c 3 * 4 * Copyright (C) 1991, 1992 Linus Torvalds 5 * 6 * proc root directory handling functions 7 */ 8 9 #include <asm/uaccess.h> 10 11 #include <linux/errno.h> 12 #include <linux/time.h> 13 #include <linux/proc_fs.h> 14 #include <linux/stat.h> 15 #include <linux/init.h> 16 #include <linux/sched.h> 17 #include <linux/module.h> 18 #include <linux/bitops.h> 19 #include <linux/smp_lock.h> 20 #include <linux/mount.h> 21 #include <linux/pid_namespace.h> 22 23 #include "internal.h" 24 25 struct proc_dir_entry *proc_bus, *proc_root_fs, *proc_root_driver; 26 27 static int proc_test_super(struct super_block *sb, void *data) 28 { 29 return sb->s_fs_info == data; 30 } 31 32 static int proc_set_super(struct super_block *sb, void *data) 33 { 34 struct pid_namespace *ns; 35 36 ns = (struct pid_namespace *)data; 37 sb->s_fs_info = get_pid_ns(ns); 38 return set_anon_super(sb, NULL); 39 } 40 41 static int proc_get_sb(struct file_system_type *fs_type, 42 int flags, const char *dev_name, void *data, struct vfsmount *mnt) 43 { 44 int err; 45 struct super_block *sb; 46 struct pid_namespace *ns; 47 struct proc_inode *ei; 48 49 if (proc_mnt) { 50 /* Seed the root directory with a pid so it doesn't need 51 * to be special in base.c. I would do this earlier but 52 * the only task alive when /proc is mounted the first time 53 * is the init_task and it doesn't have any pids. 54 */ 55 ei = PROC_I(proc_mnt->mnt_sb->s_root->d_inode); 56 if (!ei->pid) 57 ei->pid = find_get_pid(1); 58 } 59 60 if (flags & MS_KERNMOUNT) 61 ns = (struct pid_namespace *)data; 62 else 63 ns = current->nsproxy->pid_ns; 64 65 sb = sget(fs_type, proc_test_super, proc_set_super, ns); 66 if (IS_ERR(sb)) 67 return PTR_ERR(sb); 68 69 if (!sb->s_root) { 70 sb->s_flags = flags; 71 err = proc_fill_super(sb); 72 if (err) { 73 up_write(&sb->s_umount); 74 deactivate_super(sb); 75 return err; 76 } 77 78 ei = PROC_I(sb->s_root->d_inode); 79 if (!ei->pid) { 80 rcu_read_lock(); 81 ei->pid = get_pid(find_pid_ns(1, ns)); 82 rcu_read_unlock(); 83 } 84 85 sb->s_flags |= MS_ACTIVE; 86 ns->proc_mnt = mnt; 87 } 88 89 return simple_set_mnt(mnt, sb); 90 } 91 92 static void proc_kill_sb(struct super_block *sb) 93 { 94 struct pid_namespace *ns; 95 96 ns = (struct pid_namespace *)sb->s_fs_info; 97 kill_anon_super(sb); 98 put_pid_ns(ns); 99 } 100 101 static struct file_system_type proc_fs_type = { 102 .name = "proc", 103 .get_sb = proc_get_sb, 104 .kill_sb = proc_kill_sb, 105 }; 106 107 void __init proc_root_init(void) 108 { 109 int err = proc_init_inodecache(); 110 if (err) 111 return; 112 err = register_filesystem(&proc_fs_type); 113 if (err) 114 return; 115 proc_mnt = kern_mount_data(&proc_fs_type, &init_pid_ns); 116 err = PTR_ERR(proc_mnt); 117 if (IS_ERR(proc_mnt)) { 118 unregister_filesystem(&proc_fs_type); 119 return; 120 } 121 122 proc_misc_init(); 123 124 proc_net_init(); 125 126 #ifdef CONFIG_SYSVIPC 127 proc_mkdir("sysvipc", NULL); 128 #endif 129 proc_root_fs = proc_mkdir("fs", NULL); 130 proc_root_driver = proc_mkdir("driver", NULL); 131 proc_mkdir("fs/nfsd", NULL); /* somewhere for the nfsd filesystem to be mounted */ 132 #if defined(CONFIG_SUN_OPENPROMFS) || defined(CONFIG_SUN_OPENPROMFS_MODULE) 133 /* just give it a mountpoint */ 134 proc_mkdir("openprom", NULL); 135 #endif 136 proc_tty_init(); 137 #ifdef CONFIG_PROC_DEVICETREE 138 proc_device_tree_init(); 139 #endif 140 proc_bus = proc_mkdir("bus", NULL); 141 proc_sys_init(); 142 } 143 144 static int proc_root_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat 145 ) 146 { 147 generic_fillattr(dentry->d_inode, stat); 148 stat->nlink = proc_root.nlink + nr_processes(); 149 return 0; 150 } 151 152 static struct dentry *proc_root_lookup(struct inode * dir, struct dentry * dentry, struct nameidata *nd) 153 { 154 if (!proc_lookup(dir, dentry, nd)) { 155 return NULL; 156 } 157 158 return proc_pid_lookup(dir, dentry, nd); 159 } 160 161 static int proc_root_readdir(struct file * filp, 162 void * dirent, filldir_t filldir) 163 { 164 unsigned int nr = filp->f_pos; 165 int ret; 166 167 lock_kernel(); 168 169 if (nr < FIRST_PROCESS_ENTRY) { 170 int error = proc_readdir(filp, dirent, filldir); 171 if (error <= 0) { 172 unlock_kernel(); 173 return error; 174 } 175 filp->f_pos = FIRST_PROCESS_ENTRY; 176 } 177 unlock_kernel(); 178 179 ret = proc_pid_readdir(filp, dirent, filldir); 180 return ret; 181 } 182 183 /* 184 * The root /proc directory is special, as it has the 185 * <pid> directories. Thus we don't use the generic 186 * directory handling functions for that.. 187 */ 188 static const struct file_operations proc_root_operations = { 189 .read = generic_read_dir, 190 .readdir = proc_root_readdir, 191 }; 192 193 /* 194 * proc root can do almost nothing.. 195 */ 196 static const struct inode_operations proc_root_inode_operations = { 197 .lookup = proc_root_lookup, 198 .getattr = proc_root_getattr, 199 }; 200 201 /* 202 * This is the root "inode" in the /proc tree.. 203 */ 204 struct proc_dir_entry proc_root = { 205 .low_ino = PROC_ROOT_INO, 206 .namelen = 5, 207 .name = "/proc", 208 .mode = S_IFDIR | S_IRUGO | S_IXUGO, 209 .nlink = 2, 210 .count = ATOMIC_INIT(1), 211 .proc_iops = &proc_root_inode_operations, 212 .proc_fops = &proc_root_operations, 213 .parent = &proc_root, 214 }; 215 216 int pid_ns_prepare_proc(struct pid_namespace *ns) 217 { 218 struct vfsmount *mnt; 219 220 mnt = kern_mount_data(&proc_fs_type, ns); 221 if (IS_ERR(mnt)) 222 return PTR_ERR(mnt); 223 224 return 0; 225 } 226 227 void pid_ns_release_proc(struct pid_namespace *ns) 228 { 229 mntput(ns->proc_mnt); 230 } 231 232 EXPORT_SYMBOL(proc_symlink); 233 EXPORT_SYMBOL(proc_mkdir); 234 EXPORT_SYMBOL(create_proc_entry); 235 EXPORT_SYMBOL(proc_create); 236 EXPORT_SYMBOL(remove_proc_entry); 237 EXPORT_SYMBOL(proc_root); 238 EXPORT_SYMBOL(proc_root_fs); 239 EXPORT_SYMBOL(proc_bus); 240 EXPORT_SYMBOL(proc_root_driver); 241