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 static int proc_test_super(struct super_block *sb, void *data) 26 { 27 return sb->s_fs_info == data; 28 } 29 30 static int proc_set_super(struct super_block *sb, void *data) 31 { 32 struct pid_namespace *ns; 33 34 ns = (struct pid_namespace *)data; 35 sb->s_fs_info = get_pid_ns(ns); 36 return set_anon_super(sb, NULL); 37 } 38 39 static int proc_get_sb(struct file_system_type *fs_type, 40 int flags, const char *dev_name, void *data, struct vfsmount *mnt) 41 { 42 int err; 43 struct super_block *sb; 44 struct pid_namespace *ns; 45 struct proc_inode *ei; 46 47 if (proc_mnt) { 48 /* Seed the root directory with a pid so it doesn't need 49 * to be special in base.c. I would do this earlier but 50 * the only task alive when /proc is mounted the first time 51 * is the init_task and it doesn't have any pids. 52 */ 53 ei = PROC_I(proc_mnt->mnt_sb->s_root->d_inode); 54 if (!ei->pid) 55 ei->pid = find_get_pid(1); 56 } 57 58 if (flags & MS_KERNMOUNT) 59 ns = (struct pid_namespace *)data; 60 else 61 ns = current->nsproxy->pid_ns; 62 63 sb = sget(fs_type, proc_test_super, proc_set_super, ns); 64 if (IS_ERR(sb)) 65 return PTR_ERR(sb); 66 67 if (!sb->s_root) { 68 sb->s_flags = flags; 69 err = proc_fill_super(sb); 70 if (err) { 71 up_write(&sb->s_umount); 72 deactivate_super(sb); 73 return err; 74 } 75 76 ei = PROC_I(sb->s_root->d_inode); 77 if (!ei->pid) { 78 rcu_read_lock(); 79 ei->pid = get_pid(find_pid_ns(1, ns)); 80 rcu_read_unlock(); 81 } 82 83 sb->s_flags |= MS_ACTIVE; 84 ns->proc_mnt = mnt; 85 } 86 87 return simple_set_mnt(mnt, sb); 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 lock_kernel(); 166 167 if (nr < FIRST_PROCESS_ENTRY) { 168 int error = proc_readdir(filp, dirent, filldir); 169 if (error <= 0) { 170 unlock_kernel(); 171 return error; 172 } 173 filp->f_pos = FIRST_PROCESS_ENTRY; 174 } 175 unlock_kernel(); 176 177 ret = proc_pid_readdir(filp, dirent, filldir); 178 return ret; 179 } 180 181 /* 182 * The root /proc directory is special, as it has the 183 * <pid> directories. Thus we don't use the generic 184 * directory handling functions for that.. 185 */ 186 static const struct file_operations proc_root_operations = { 187 .read = generic_read_dir, 188 .readdir = proc_root_readdir, 189 }; 190 191 /* 192 * proc root can do almost nothing.. 193 */ 194 static const struct inode_operations proc_root_inode_operations = { 195 .lookup = proc_root_lookup, 196 .getattr = proc_root_getattr, 197 }; 198 199 /* 200 * This is the root "inode" in the /proc tree.. 201 */ 202 struct proc_dir_entry proc_root = { 203 .low_ino = PROC_ROOT_INO, 204 .namelen = 5, 205 .name = "/proc", 206 .mode = S_IFDIR | S_IRUGO | S_IXUGO, 207 .nlink = 2, 208 .count = ATOMIC_INIT(1), 209 .proc_iops = &proc_root_inode_operations, 210 .proc_fops = &proc_root_operations, 211 .parent = &proc_root, 212 }; 213 214 int pid_ns_prepare_proc(struct pid_namespace *ns) 215 { 216 struct vfsmount *mnt; 217 218 mnt = kern_mount_data(&proc_fs_type, ns); 219 if (IS_ERR(mnt)) 220 return PTR_ERR(mnt); 221 222 return 0; 223 } 224 225 void pid_ns_release_proc(struct pid_namespace *ns) 226 { 227 mntput(ns->proc_mnt); 228 } 229 230 EXPORT_SYMBOL(proc_symlink); 231 EXPORT_SYMBOL(proc_mkdir); 232 EXPORT_SYMBOL(create_proc_entry); 233 EXPORT_SYMBOL(proc_create_data); 234 EXPORT_SYMBOL(remove_proc_entry); 235