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/mount.h> 20 #include <linux/pid_namespace.h> 21 22 #include "internal.h" 23 24 static int proc_test_super(struct super_block *sb, void *data) 25 { 26 return sb->s_fs_info == data; 27 } 28 29 static int proc_set_super(struct super_block *sb, void *data) 30 { 31 int err = set_anon_super(sb, NULL); 32 if (!err) { 33 struct pid_namespace *ns = (struct pid_namespace *)data; 34 sb->s_fs_info = get_pid_ns(ns); 35 } 36 return err; 37 } 38 39 static struct dentry *proc_mount(struct file_system_type *fs_type, 40 int flags, const char *dev_name, void *data) 41 { 42 int err; 43 struct super_block *sb; 44 struct pid_namespace *ns; 45 struct proc_inode *ei; 46 47 if (flags & MS_KERNMOUNT) 48 ns = (struct pid_namespace *)data; 49 else 50 ns = current->nsproxy->pid_ns; 51 52 sb = sget(fs_type, proc_test_super, proc_set_super, ns); 53 if (IS_ERR(sb)) 54 return ERR_CAST(sb); 55 56 if (!sb->s_root) { 57 sb->s_flags = flags; 58 err = proc_fill_super(sb); 59 if (err) { 60 deactivate_locked_super(sb); 61 return ERR_PTR(err); 62 } 63 64 sb->s_flags |= MS_ACTIVE; 65 } 66 67 ei = PROC_I(sb->s_root->d_inode); 68 if (!ei->pid) { 69 rcu_read_lock(); 70 ei->pid = get_pid(find_pid_ns(1, ns)); 71 rcu_read_unlock(); 72 } 73 74 return dget(sb->s_root); 75 } 76 77 static void proc_kill_sb(struct super_block *sb) 78 { 79 struct pid_namespace *ns; 80 81 ns = (struct pid_namespace *)sb->s_fs_info; 82 kill_anon_super(sb); 83 put_pid_ns(ns); 84 } 85 86 static struct file_system_type proc_fs_type = { 87 .name = "proc", 88 .mount = proc_mount, 89 .kill_sb = proc_kill_sb, 90 }; 91 92 void __init proc_root_init(void) 93 { 94 struct vfsmount *mnt; 95 int err; 96 97 proc_init_inodecache(); 98 err = register_filesystem(&proc_fs_type); 99 if (err) 100 return; 101 mnt = kern_mount_data(&proc_fs_type, &init_pid_ns); 102 if (IS_ERR(mnt)) { 103 unregister_filesystem(&proc_fs_type); 104 return; 105 } 106 107 init_pid_ns.proc_mnt = mnt; 108 proc_symlink("mounts", NULL, "self/mounts"); 109 110 proc_net_init(); 111 112 #ifdef CONFIG_SYSVIPC 113 proc_mkdir("sysvipc", NULL); 114 #endif 115 proc_mkdir("fs", NULL); 116 proc_mkdir("driver", NULL); 117 proc_mkdir("fs/nfsd", NULL); /* somewhere for the nfsd filesystem to be mounted */ 118 #if defined(CONFIG_SUN_OPENPROMFS) || defined(CONFIG_SUN_OPENPROMFS_MODULE) 119 /* just give it a mountpoint */ 120 proc_mkdir("openprom", NULL); 121 #endif 122 proc_tty_init(); 123 #ifdef CONFIG_PROC_DEVICETREE 124 proc_device_tree_init(); 125 #endif 126 proc_mkdir("bus", NULL); 127 proc_sys_init(); 128 } 129 130 static int proc_root_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat 131 ) 132 { 133 generic_fillattr(dentry->d_inode, stat); 134 stat->nlink = proc_root.nlink + nr_processes(); 135 return 0; 136 } 137 138 static struct dentry *proc_root_lookup(struct inode * dir, struct dentry * dentry, struct nameidata *nd) 139 { 140 if (!proc_lookup(dir, dentry, nd)) { 141 return NULL; 142 } 143 144 return proc_pid_lookup(dir, dentry, nd); 145 } 146 147 static int proc_root_readdir(struct file * filp, 148 void * dirent, filldir_t filldir) 149 { 150 unsigned int nr = filp->f_pos; 151 int ret; 152 153 if (nr < FIRST_PROCESS_ENTRY) { 154 int error = proc_readdir(filp, dirent, filldir); 155 if (error <= 0) 156 return error; 157 filp->f_pos = FIRST_PROCESS_ENTRY; 158 } 159 160 ret = proc_pid_readdir(filp, dirent, filldir); 161 return ret; 162 } 163 164 /* 165 * The root /proc directory is special, as it has the 166 * <pid> directories. Thus we don't use the generic 167 * directory handling functions for that.. 168 */ 169 static const struct file_operations proc_root_operations = { 170 .read = generic_read_dir, 171 .readdir = proc_root_readdir, 172 .llseek = default_llseek, 173 }; 174 175 /* 176 * proc root can do almost nothing.. 177 */ 178 static const struct inode_operations proc_root_inode_operations = { 179 .lookup = proc_root_lookup, 180 .getattr = proc_root_getattr, 181 }; 182 183 /* 184 * This is the root "inode" in the /proc tree.. 185 */ 186 struct proc_dir_entry proc_root = { 187 .low_ino = PROC_ROOT_INO, 188 .namelen = 5, 189 .mode = S_IFDIR | S_IRUGO | S_IXUGO, 190 .nlink = 2, 191 .count = ATOMIC_INIT(1), 192 .proc_iops = &proc_root_inode_operations, 193 .proc_fops = &proc_root_operations, 194 .parent = &proc_root, 195 .name = "/proc", 196 }; 197 198 int pid_ns_prepare_proc(struct pid_namespace *ns) 199 { 200 struct vfsmount *mnt; 201 202 mnt = kern_mount_data(&proc_fs_type, ns); 203 if (IS_ERR(mnt)) 204 return PTR_ERR(mnt); 205 206 ns->proc_mnt = mnt; 207 return 0; 208 } 209 210 void pid_ns_release_proc(struct pid_namespace *ns) 211 { 212 mntput(ns->proc_mnt); 213 } 214