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