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 up_write(&sb->s_umount); 71 deactivate_super(sb); 72 return err; 73 } 74 75 ei = PROC_I(sb->s_root->d_inode); 76 if (!ei->pid) { 77 rcu_read_lock(); 78 ei->pid = get_pid(find_pid_ns(1, ns)); 79 rcu_read_unlock(); 80 } 81 82 sb->s_flags |= MS_ACTIVE; 83 ns->proc_mnt = mnt; 84 } 85 86 simple_set_mnt(mnt, sb); 87 return 0; 88 } 89 90 static void proc_kill_sb(struct super_block *sb) 91 { 92 struct pid_namespace *ns; 93 94 ns = (struct pid_namespace *)sb->s_fs_info; 95 kill_anon_super(sb); 96 put_pid_ns(ns); 97 } 98 99 static struct file_system_type proc_fs_type = { 100 .name = "proc", 101 .get_sb = proc_get_sb, 102 .kill_sb = proc_kill_sb, 103 }; 104 105 void __init proc_root_init(void) 106 { 107 int err; 108 109 proc_init_inodecache(); 110 err = register_filesystem(&proc_fs_type); 111 if (err) 112 return; 113 proc_mnt = kern_mount_data(&proc_fs_type, &init_pid_ns); 114 err = PTR_ERR(proc_mnt); 115 if (IS_ERR(proc_mnt)) { 116 unregister_filesystem(&proc_fs_type); 117 return; 118 } 119 120 proc_symlink("mounts", NULL, "self/mounts"); 121 122 proc_net_init(); 123 124 #ifdef CONFIG_SYSVIPC 125 proc_mkdir("sysvipc", NULL); 126 #endif 127 proc_mkdir("fs", NULL); 128 proc_mkdir("driver", NULL); 129 proc_mkdir("fs/nfsd", NULL); /* somewhere for the nfsd filesystem to be mounted */ 130 #if defined(CONFIG_SUN_OPENPROMFS) || defined(CONFIG_SUN_OPENPROMFS_MODULE) 131 /* just give it a mountpoint */ 132 proc_mkdir("openprom", NULL); 133 #endif 134 proc_tty_init(); 135 #ifdef CONFIG_PROC_DEVICETREE 136 proc_device_tree_init(); 137 #endif 138 proc_mkdir("bus", NULL); 139 proc_sys_init(); 140 } 141 142 static int proc_root_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat 143 ) 144 { 145 generic_fillattr(dentry->d_inode, stat); 146 stat->nlink = proc_root.nlink + nr_processes(); 147 return 0; 148 } 149 150 static struct dentry *proc_root_lookup(struct inode * dir, struct dentry * dentry, struct nameidata *nd) 151 { 152 if (!proc_lookup(dir, dentry, nd)) { 153 return NULL; 154 } 155 156 return proc_pid_lookup(dir, dentry, nd); 157 } 158 159 static int proc_root_readdir(struct file * filp, 160 void * dirent, filldir_t filldir) 161 { 162 unsigned int nr = filp->f_pos; 163 int ret; 164 165 if (nr < FIRST_PROCESS_ENTRY) { 166 int error = proc_readdir(filp, dirent, filldir); 167 if (error <= 0) 168 return error; 169 filp->f_pos = FIRST_PROCESS_ENTRY; 170 } 171 172 ret = proc_pid_readdir(filp, dirent, filldir); 173 return ret; 174 } 175 176 /* 177 * The root /proc directory is special, as it has the 178 * <pid> directories. Thus we don't use the generic 179 * directory handling functions for that.. 180 */ 181 static const struct file_operations proc_root_operations = { 182 .read = generic_read_dir, 183 .readdir = proc_root_readdir, 184 }; 185 186 /* 187 * proc root can do almost nothing.. 188 */ 189 static const struct inode_operations proc_root_inode_operations = { 190 .lookup = proc_root_lookup, 191 .getattr = proc_root_getattr, 192 }; 193 194 /* 195 * This is the root "inode" in the /proc tree.. 196 */ 197 struct proc_dir_entry proc_root = { 198 .low_ino = PROC_ROOT_INO, 199 .namelen = 5, 200 .name = "/proc", 201 .mode = S_IFDIR | S_IRUGO | S_IXUGO, 202 .nlink = 2, 203 .count = ATOMIC_INIT(1), 204 .proc_iops = &proc_root_inode_operations, 205 .proc_fops = &proc_root_operations, 206 .parent = &proc_root, 207 }; 208 209 int pid_ns_prepare_proc(struct pid_namespace *ns) 210 { 211 struct vfsmount *mnt; 212 213 mnt = kern_mount_data(&proc_fs_type, ns); 214 if (IS_ERR(mnt)) 215 return PTR_ERR(mnt); 216 217 return 0; 218 } 219 220 void pid_ns_release_proc(struct pid_namespace *ns) 221 { 222 mntput(ns->proc_mnt); 223 } 224 225 EXPORT_SYMBOL(proc_symlink); 226 EXPORT_SYMBOL(proc_mkdir); 227 EXPORT_SYMBOL(create_proc_entry); 228 EXPORT_SYMBOL(proc_create_data); 229 EXPORT_SYMBOL(remove_proc_entry); 230