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