/* * linux/fs/proc/root.c * * Copyright (C) 1991, 1992 Linus Torvalds * * proc root directory handling functions */ #include <asm/uaccess.h> #include <linux/errno.h> #include <linux/time.h> #include <linux/proc_fs.h> #include <linux/stat.h> #include <linux/init.h> #include <linux/sched.h> #include <linux/module.h> #include <linux/bitops.h> #include <linux/mount.h> #include <linux/pid_namespace.h> #include <linux/parser.h> #include "internal.h" static int proc_test_super(struct super_block *sb, void *data) { return sb->s_fs_info == data; } static int proc_set_super(struct super_block *sb, void *data) { int err = set_anon_super(sb, NULL); if (!err) { struct pid_namespace *ns = (struct pid_namespace *)data; sb->s_fs_info = get_pid_ns(ns); } return err; } enum { Opt_gid, Opt_hidepid, Opt_err, }; static const match_table_t tokens = { {Opt_hidepid, "hidepid=%u"}, {Opt_gid, "gid=%u"}, {Opt_err, NULL}, }; static int proc_parse_options(char *options, struct pid_namespace *pid) { char *p; substring_t args[MAX_OPT_ARGS]; int option; if (!options) return 1; while ((p = strsep(&options, ",")) != NULL) { int token; if (!*p) continue; args[0].to = args[0].from = 0; token = match_token(p, tokens, args); switch (token) { case Opt_gid: if (match_int(&args[0], &option)) return 0; pid->pid_gid = option; break; case Opt_hidepid: if (match_int(&args[0], &option)) return 0; if (option < 0 || option > 2) { pr_err("proc: hidepid value must be between 0 and 2.\n"); return 0; } pid->hide_pid = option; break; default: pr_err("proc: unrecognized mount option \"%s\" " "or missing value\n", p); return 0; } } return 1; } int proc_remount(struct super_block *sb, int *flags, char *data) { struct pid_namespace *pid = sb->s_fs_info; return !proc_parse_options(data, pid); } static struct dentry *proc_mount(struct file_system_type *fs_type, int flags, const char *dev_name, void *data) { int err; struct super_block *sb; struct pid_namespace *ns; struct proc_inode *ei; char *options; if (flags & MS_KERNMOUNT) { ns = (struct pid_namespace *)data; options = NULL; } else { ns = current->nsproxy->pid_ns; options = data; } sb = sget(fs_type, proc_test_super, proc_set_super, ns); if (IS_ERR(sb)) return ERR_CAST(sb); if (!sb->s_root) { sb->s_flags = flags; if (!proc_parse_options(options, ns)) { deactivate_locked_super(sb); return ERR_PTR(-EINVAL); } err = proc_fill_super(sb); if (err) { deactivate_locked_super(sb); return ERR_PTR(err); } sb->s_flags |= MS_ACTIVE; } ei = PROC_I(sb->s_root->d_inode); if (!ei->pid) { rcu_read_lock(); ei->pid = get_pid(find_pid_ns(1, ns)); rcu_read_unlock(); } return dget(sb->s_root); } static void proc_kill_sb(struct super_block *sb) { struct pid_namespace *ns; ns = (struct pid_namespace *)sb->s_fs_info; kill_anon_super(sb); put_pid_ns(ns); } static struct file_system_type proc_fs_type = { .name = "proc", .mount = proc_mount, .kill_sb = proc_kill_sb, }; void __init proc_root_init(void) { int err; proc_init_inodecache(); err = register_filesystem(&proc_fs_type); if (err) return; err = pid_ns_prepare_proc(&init_pid_ns); if (err) { unregister_filesystem(&proc_fs_type); return; } proc_symlink("mounts", NULL, "self/mounts"); proc_net_init(); #ifdef CONFIG_SYSVIPC proc_mkdir("sysvipc", NULL); #endif proc_mkdir("fs", NULL); proc_mkdir("driver", NULL); proc_mkdir("fs/nfsd", NULL); /* somewhere for the nfsd filesystem to be mounted */ #if defined(CONFIG_SUN_OPENPROMFS) || defined(CONFIG_SUN_OPENPROMFS_MODULE) /* just give it a mountpoint */ proc_mkdir("openprom", NULL); #endif proc_tty_init(); #ifdef CONFIG_PROC_DEVICETREE proc_device_tree_init(); #endif proc_mkdir("bus", NULL); proc_sys_init(); } static int proc_root_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat ) { generic_fillattr(dentry->d_inode, stat); stat->nlink = proc_root.nlink + nr_processes(); return 0; } static struct dentry *proc_root_lookup(struct inode * dir, struct dentry * dentry, struct nameidata *nd) { if (!proc_lookup(dir, dentry, nd)) { return NULL; } return proc_pid_lookup(dir, dentry, nd); } static int proc_root_readdir(struct file * filp, void * dirent, filldir_t filldir) { unsigned int nr = filp->f_pos; int ret; if (nr < FIRST_PROCESS_ENTRY) { int error = proc_readdir(filp, dirent, filldir); if (error <= 0) return error; filp->f_pos = FIRST_PROCESS_ENTRY; } ret = proc_pid_readdir(filp, dirent, filldir); return ret; } /* * The root /proc directory is special, as it has the * <pid> directories. Thus we don't use the generic * directory handling functions for that.. */ static const struct file_operations proc_root_operations = { .read = generic_read_dir, .readdir = proc_root_readdir, .llseek = default_llseek, }; /* * proc root can do almost nothing.. */ static const struct inode_operations proc_root_inode_operations = { .lookup = proc_root_lookup, .getattr = proc_root_getattr, }; /* * This is the root "inode" in the /proc tree.. */ struct proc_dir_entry proc_root = { .low_ino = PROC_ROOT_INO, .namelen = 5, .mode = S_IFDIR | S_IRUGO | S_IXUGO, .nlink = 2, .count = ATOMIC_INIT(1), .proc_iops = &proc_root_inode_operations, .proc_fops = &proc_root_operations, .parent = &proc_root, .name = "/proc", }; int pid_ns_prepare_proc(struct pid_namespace *ns) { struct vfsmount *mnt; mnt = kern_mount_data(&proc_fs_type, ns); if (IS_ERR(mnt)) return PTR_ERR(mnt); ns->proc_mnt = mnt; return 0; } void pid_ns_release_proc(struct pid_namespace *ns) { kern_unmount(ns->proc_mnt); }