[linux-block.git] / fs / proc / root.c

// SPDX-License-Identifier: GPL-2.0
/*
 *  linux/fs/proc/root.c
 *
 *  Copyright (C) 1991, 1992 Linus Torvalds
 *
 *  proc root directory handling functions
 */

#include <linux/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/sched/stat.h>
#include <linux/module.h>
#include <linux/bitops.h>
#include <linux/user_namespace.h>
#include <linux/fs_context.h>
#include <linux/mount.h>
#include <linux/pid_namespace.h>
#include <linux/fs_parser.h>
#include <linux/cred.h>
#include <linux/magic.h>
#include <linux/slab.h>

#include "internal.h"

struct proc_fs_context {
	struct pid_namespace	*pid_ns;
	unsigned int		mask;
	enum proc_hidepid	hidepid;
	int			gid;
	enum proc_pidonly	pidonly;
};

enum proc_param {
	Opt_gid,
	Opt_hidepid,
	Opt_subset,
};

static const struct fs_parameter_spec proc_fs_parameters[] = {
	fsparam_u32("gid",	Opt_gid),
	fsparam_string("hidepid",	Opt_hidepid),
	fsparam_string("subset",	Opt_subset),
	{}
};

static inline int valid_hidepid(unsigned int value)
{
	return (value == HIDEPID_OFF ||
		value == HIDEPID_NO_ACCESS ||
		value == HIDEPID_INVISIBLE ||
		value == HIDEPID_NOT_PTRACEABLE);
}

static int proc_parse_hidepid_param(struct fs_context *fc, struct fs_parameter *param)
{
	struct proc_fs_context *ctx = fc->fs_private;
	struct fs_parameter_spec hidepid_u32_spec = fsparam_u32("hidepid", Opt_hidepid);
	struct fs_parse_result result;
	int base = (unsigned long)hidepid_u32_spec.data;

	if (param->type != fs_value_is_string)
		return invalf(fc, "proc: unexpected type of hidepid value\n");

	if (!kstrtouint(param->string, base, &result.uint_32)) {
		if (!valid_hidepid(result.uint_32))
			return invalf(fc, "proc: unknown value of hidepid - %s\n", param->string);
		ctx->hidepid = result.uint_32;
		return 0;
	}

	if (!strcmp(param->string, "off"))
		ctx->hidepid = HIDEPID_OFF;
	else if (!strcmp(param->string, "noaccess"))
		ctx->hidepid = HIDEPID_NO_ACCESS;
	else if (!strcmp(param->string, "invisible"))
		ctx->hidepid = HIDEPID_INVISIBLE;
	else if (!strcmp(param->string, "ptraceable"))
		ctx->hidepid = HIDEPID_NOT_PTRACEABLE;
	else
		return invalf(fc, "proc: unknown value of hidepid - %s\n", param->string);

	return 0;
}

static int proc_parse_subset_param(struct fs_context *fc, char *value)
{
	struct proc_fs_context *ctx = fc->fs_private;

	while (value) {
		char *ptr = strchr(value, ',');

		if (ptr != NULL)
			*ptr++ = '\0';

		if (*value != '\0') {
			if (!strcmp(value, "pid")) {
				ctx->pidonly = PROC_PIDONLY_ON;
			} else {
				return invalf(fc, "proc: unsupported subset option - %s\n", value);
			}
		}
		value = ptr;
	}

	return 0;
}

static int proc_parse_param(struct fs_context *fc, struct fs_parameter *param)
{
	struct proc_fs_context *ctx = fc->fs_private;
	struct fs_parse_result result;
	int opt;

	opt = fs_parse(fc, proc_fs_parameters, param, &result);
	if (opt < 0)
		return opt;

	switch (opt) {
	case Opt_gid:
		ctx->gid = result.uint_32;
		break;

	case Opt_hidepid:
		if (proc_parse_hidepid_param(fc, param))
			return -EINVAL;
		break;

	case Opt_subset:
		if (proc_parse_subset_param(fc, param->string) < 0)
			return -EINVAL;
		break;

	default:
		return -EINVAL;
	}

	ctx->mask |= 1 << opt;
	return 0;
}

static void proc_apply_options(struct proc_fs_info *fs_info,
			       struct fs_context *fc,
			       struct user_namespace *user_ns)
{
	struct proc_fs_context *ctx = fc->fs_private;

	if (ctx->mask & (1 << Opt_gid))
		fs_info->pid_gid = make_kgid(user_ns, ctx->gid);
	if (ctx->mask & (1 << Opt_hidepid))
		fs_info->hide_pid = ctx->hidepid;
	if (ctx->mask & (1 << Opt_subset))
		fs_info->pidonly = ctx->pidonly;
}

static int proc_fill_super(struct super_block *s, struct fs_context *fc)
{
	struct proc_fs_context *ctx = fc->fs_private;
	struct inode *root_inode;
	struct proc_fs_info *fs_info;
	int ret;

	fs_info = kzalloc(sizeof(*fs_info), GFP_KERNEL);
	if (!fs_info)
		return -ENOMEM;

	fs_info->pid_ns = get_pid_ns(ctx->pid_ns);
	proc_apply_options(fs_info, fc, current_user_ns());

	/* User space would break if executables or devices appear on proc */
	s->s_iflags |= SB_I_USERNS_VISIBLE | SB_I_NOEXEC | SB_I_NODEV;
	s->s_flags |= SB_NODIRATIME | SB_NOSUID | SB_NOEXEC;
	s->s_blocksize = 1024;
	s->s_blocksize_bits = 10;
	s->s_magic = PROC_SUPER_MAGIC;
	s->s_op = &proc_sops;
	s->s_time_gran = 1;
	s->s_fs_info = fs_info;

	/*
	 * procfs isn't actually a stacking filesystem; however, there is
	 * too much magic going on inside it to permit stacking things on
	 * top of it
	 */
	s->s_stack_depth = FILESYSTEM_MAX_STACK_DEPTH;

	/* procfs dentries and inodes don't require IO to create */
	s->s_shrink.seeks = 0;

	pde_get(&proc_root);
	root_inode = proc_get_inode(s, &proc_root);
	if (!root_inode) {
		pr_err("proc_fill_super: get root inode failed\n");
		return -ENOMEM;
	}

	s->s_root = d_make_root(root_inode);
	if (!s->s_root) {
		pr_err("proc_fill_super: allocate dentry failed\n");
		return -ENOMEM;
	}

	ret = proc_setup_self(s);
	if (ret) {
		return ret;
	}
	return proc_setup_thread_self(s);
}

static int proc_reconfigure(struct fs_context *fc)
{
	struct super_block *sb = fc->root->d_sb;
	struct proc_fs_info *fs_info = proc_sb_info(sb);

	sync_filesystem(sb);

	proc_apply_options(fs_info, fc, current_user_ns());
	return 0;
}

static int proc_get_tree(struct fs_context *fc)
{
	return get_tree_nodev(fc, proc_fill_super);
}

static void proc_fs_context_free(struct fs_context *fc)
{
	struct proc_fs_context *ctx = fc->fs_private;

	put_pid_ns(ctx->pid_ns);
	kfree(ctx);
}

static const struct fs_context_operations proc_fs_context_ops = {
	.free		= proc_fs_context_free,
	.parse_param	= proc_parse_param,
	.get_tree	= proc_get_tree,
	.reconfigure	= proc_reconfigure,
};

static int proc_init_fs_context(struct fs_context *fc)
{
	struct proc_fs_context *ctx;

	ctx = kzalloc(sizeof(struct proc_fs_context), GFP_KERNEL);
	if (!ctx)
		return -ENOMEM;

	ctx->pid_ns = get_pid_ns(task_active_pid_ns(current));
	put_user_ns(fc->user_ns);
	fc->user_ns = get_user_ns(ctx->pid_ns->user_ns);
	fc->fs_private = ctx;
	fc->ops = &proc_fs_context_ops;
	return 0;
}

static void proc_kill_sb(struct super_block *sb)
{
	struct proc_fs_info *fs_info = proc_sb_info(sb);

	if (!fs_info) {
		kill_anon_super(sb);
		return;
	}

	dput(fs_info->proc_self);
	dput(fs_info->proc_thread_self);

	kill_anon_super(sb);
	put_pid_ns(fs_info->pid_ns);
	kfree(fs_info);
}

static struct file_system_type proc_fs_type = {
	.name			= "proc",
	.init_fs_context	= proc_init_fs_context,
	.parameters		= proc_fs_parameters,
	.kill_sb		= proc_kill_sb,
	.fs_flags		= FS_USERNS_MOUNT | FS_DISALLOW_NOTIFY_PERM,
};

void __init proc_root_init(void)
{
	proc_init_kmemcache();
	set_proc_pid_nlink();
	proc_self_init();
	proc_thread_self_init();
	proc_symlink("mounts", NULL, "self/mounts");

	proc_net_init();
	proc_mkdir("fs", NULL);
	proc_mkdir("driver", NULL);
	proc_create_mount_point("fs/nfsd"); /* somewhere for the nfsd filesystem to be mounted */
#if defined(CONFIG_SUN_OPENPROMFS) || defined(CONFIG_SUN_OPENPROMFS_MODULE)
	/* just give it a mountpoint */
	proc_create_mount_point("openprom");
#endif
	proc_tty_init();
	proc_mkdir("bus", NULL);
	proc_sys_init();

	register_filesystem(&proc_fs_type);
}

static int proc_root_getattr(const struct path *path, struct kstat *stat,
			     u32 request_mask, unsigned int query_flags)
{
	generic_fillattr(&init_user_ns, d_inode(path->dentry), stat);
	stat->nlink = proc_root.nlink + nr_processes();
	return 0;
}

static struct dentry *proc_root_lookup(struct inode * dir, struct dentry * dentry, unsigned int flags)
{
	if (!proc_pid_lookup(dentry, flags))
		return NULL;

	return proc_lookup(dir, dentry, flags);
}

static int proc_root_readdir(struct file *file, struct dir_context *ctx)
{
	if (ctx->pos < FIRST_PROCESS_ENTRY) {
		int error = proc_readdir(file, ctx);
		if (unlikely(error <= 0))
			return error;
		ctx->pos = FIRST_PROCESS_ENTRY;
	}

	return proc_pid_readdir(file, ctx);
}

/*
 * 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,
	.iterate_shared	 = proc_root_readdir,
	.llseek		= generic_file_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, 
	.refcnt		= REFCOUNT_INIT(1),
	.proc_iops	= &proc_root_inode_operations, 
	.proc_dir_ops	= &proc_root_operations,
	.parent		= &proc_root,
	.subdir		= RB_ROOT,
	.name		= "/proc",
};
Commit	Line	Data
b2441318	1	// SPDX-License-Identifier: GPL-2.0
1da177e4 LT	2	/*
	3	* linux/fs/proc/root.c
	4	*
	5	* Copyright (C) 1991, 1992 Linus Torvalds
	6	*
	7	* proc root directory handling functions
	8	*/
	9
7c0f6ba6	10	#include <linux/uaccess.h>
1da177e4 LT	11
	12	#include <linux/errno.h>
	13	#include <linux/time.h>
	14	#include <linux/proc_fs.h>
	15	#include <linux/stat.h>
1da177e4	16	#include <linux/init.h>
914e2637	17	#include <linux/sched.h>
03441a34	18	#include <linux/sched/stat.h>
1da177e4 LT	19	#include <linux/module.h>
1da177e4 LT	20	#include <linux/bitops.h>
87a8ebd6	21	#include <linux/user_namespace.h>
66f592e2	22	#include <linux/fs_context.h>
f6c7a1f3	23	#include <linux/mount.h>
07543f5c	24	#include <linux/pid_namespace.h>
66f592e2	25	#include <linux/fs_parser.h>
5b825c3a	26	#include <linux/cred.h>
60a3c3a5	27	#include <linux/magic.h>
66f592e2	28	#include <linux/slab.h>
1da177e4	29
fee781e6 AB	30	#include "internal.h"
fee781e6 AB	31
66f592e2 DH	32	struct proc_fs_context {
	33	struct pid_namespace *pid_ns;
	34	unsigned int mask;
e61bb8b3	35	enum proc_hidepid hidepid;
66f592e2	36	int gid;
e61bb8b3	37	enum proc_pidonly pidonly;
97412950 VK	38	};
97412950 VK	39
66f592e2 DH	40	enum proc_param {
	41	Opt_gid,
	42	Opt_hidepid,
6814ef2d	43	Opt_subset,
97412950 VK	44	};
97412950 VK	45
d7167b14	46	static const struct fs_parameter_spec proc_fs_parameters[] = {
66f592e2	47	fsparam_u32("gid", Opt_gid),
1c6c4d11	48	fsparam_string("hidepid", Opt_hidepid),
6814ef2d	49	fsparam_string("subset", Opt_subset),
66f592e2 DH	50	{}
	51	};
	52
24a71ce5 AG	53	static inline int valid_hidepid(unsigned int value)
	54	{
	55	return (value == HIDEPID_OFF \|\|
	56	value == HIDEPID_NO_ACCESS \|\|
	57	value == HIDEPID_INVISIBLE \|\|
	58	value == HIDEPID_NOT_PTRACEABLE);
	59	}
	60
1c6c4d11 AG	61	static int proc_parse_hidepid_param(struct fs_context fc, struct fs_parameter param)
	62	{
	63	struct proc_fs_context *ctx = fc->fs_private;
	64	struct fs_parameter_spec hidepid_u32_spec = fsparam_u32("hidepid", Opt_hidepid);
	65	struct fs_parse_result result;
	66	int base = (unsigned long)hidepid_u32_spec.data;
	67
	68	if (param->type != fs_value_is_string)
	69	return invalf(fc, "proc: unexpected type of hidepid value\n");
	70
	71	if (!kstrtouint(param->string, base, &result.uint_32)) {
	72	if (!valid_hidepid(result.uint_32))
	73	return invalf(fc, "proc: unknown value of hidepid - %s\n", param->string);
	74	ctx->hidepid = result.uint_32;
	75	return 0;
	76	}
	77
	78	if (!strcmp(param->string, "off"))
	79	ctx->hidepid = HIDEPID_OFF;
	80	else if (!strcmp(param->string, "noaccess"))
	81	ctx->hidepid = HIDEPID_NO_ACCESS;
	82	else if (!strcmp(param->string, "invisible"))
	83	ctx->hidepid = HIDEPID_INVISIBLE;
	84	else if (!strcmp(param->string, "ptraceable"))
	85	ctx->hidepid = HIDEPID_NOT_PTRACEABLE;
	86	else
	87	return invalf(fc, "proc: unknown value of hidepid - %s\n", param->string);
	88
	89	return 0;
	90	}
	91
6814ef2d AG	92	static int proc_parse_subset_param(struct fs_context fc, char value)
	93	{
	94	struct proc_fs_context *ctx = fc->fs_private;
	95
	96	while (value) {
	97	char *ptr = strchr(value, ',');
	98
	99	if (ptr != NULL)
	100	*ptr++ = '\0';
	101
	102	if (*value != '\0') {
	103	if (!strcmp(value, "pid")) {
	104	ctx->pidonly = PROC_PIDONLY_ON;
	105	} else {
	106	return invalf(fc, "proc: unsupported subset option - %s\n", value);
	107	}
	108	}
	109	value = ptr;
	110	}
	111
	112	return 0;
	113	}
	114
66f592e2	115	static int proc_parse_param(struct fs_context fc, struct fs_parameter param)
97412950	116	{
66f592e2 DH	117	struct proc_fs_context *ctx = fc->fs_private;
	118	struct fs_parse_result result;
	119	int opt;
	120
d7167b14	121	opt = fs_parse(fc, proc_fs_parameters, param, &result);
66f592e2 DH	122	if (opt < 0)
	123	return opt;
	124
	125	switch (opt) {
	126	case Opt_gid:
	127	ctx->gid = result.uint_32;
	128	break;
	129
	130	case Opt_hidepid:
1c6c4d11 AG	131	if (proc_parse_hidepid_param(fc, param))
1c6c4d11 AG	132	return -EINVAL;
66f592e2 DH	133	break;
66f592e2 DH	134
6814ef2d AG	135	case Opt_subset:
	136	if (proc_parse_subset_param(fc, param->string) < 0)
	137	return -EINVAL;
	138	break;
	139
66f592e2 DH	140	default:
66f592e2 DH	141	return -EINVAL;
97412950 VK	142	}
97412950 VK	143
66f592e2 DH	144	ctx->mask \|= 1 << opt;
66f592e2 DH	145	return 0;
97412950 VK	146	}
97412950 VK	147
fa10fed3	148	static void proc_apply_options(struct proc_fs_info *fs_info,
66f592e2	149	struct fs_context *fc,
66f592e2	150	struct user_namespace *user_ns)
97412950	151	{
66f592e2 DH	152	struct proc_fs_context *ctx = fc->fs_private;
	153
	154	if (ctx->mask & (1 << Opt_gid))
fa10fed3	155	fs_info->pid_gid = make_kgid(user_ns, ctx->gid);
66f592e2	156	if (ctx->mask & (1 << Opt_hidepid))
fa10fed3	157	fs_info->hide_pid = ctx->hidepid;
6814ef2d AG	158	if (ctx->mask & (1 << Opt_subset))
6814ef2d AG	159	fs_info->pidonly = ctx->pidonly;
97412950 VK	160	}
97412950 VK	161
66f592e2	162	static int proc_fill_super(struct super_block s, struct fs_context fc)
60a3c3a5	163	{
fa10fed3	164	struct proc_fs_context *ctx = fc->fs_private;
60a3c3a5	165	struct inode *root_inode;
fa10fed3	166	struct proc_fs_info *fs_info;
60a3c3a5 DH	167	int ret;
60a3c3a5 DH	168
fa10fed3 AG	169	fs_info = kzalloc(sizeof(*fs_info), GFP_KERNEL);
	170	if (!fs_info)
	171	return -ENOMEM;
	172
	173	fs_info->pid_ns = get_pid_ns(ctx->pid_ns);
	174	proc_apply_options(fs_info, fc, current_user_ns());
60a3c3a5 DH	175
	176	/* User space would break if executables or devices appear on proc */
	177	s->s_iflags \|= SB_I_USERNS_VISIBLE \| SB_I_NOEXEC \| SB_I_NODEV;
	178	s->s_flags \|= SB_NODIRATIME \| SB_NOSUID \| SB_NOEXEC;
	179	s->s_blocksize = 1024;
	180	s->s_blocksize_bits = 10;
	181	s->s_magic = PROC_SUPER_MAGIC;
	182	s->s_op = &proc_sops;
	183	s->s_time_gran = 1;
fa10fed3	184	s->s_fs_info = fs_info;
60a3c3a5 DH	185
	186	/*
	187	* procfs isn't actually a stacking filesystem; however, there is
	188	* too much magic going on inside it to permit stacking things on
	189	* top of it
	190	*/
	191	s->s_stack_depth = FILESYSTEM_MAX_STACK_DEPTH;
fa10fed3	192
60a3c3a5 DH	193	/* procfs dentries and inodes don't require IO to create */
	194	s->s_shrink.seeks = 0;
	195
	196	pde_get(&proc_root);
	197	root_inode = proc_get_inode(s, &proc_root);
	198	if (!root_inode) {
	199	pr_err("proc_fill_super: get root inode failed\n");
	200	return -ENOMEM;
	201	}
	202
	203	s->s_root = d_make_root(root_inode);
	204	if (!s->s_root) {
	205	pr_err("proc_fill_super: allocate dentry failed\n");
	206	return -ENOMEM;
	207	}
	208
	209	ret = proc_setup_self(s);
	210	if (ret) {
	211	return ret;
	212	}
	213	return proc_setup_thread_self(s);
	214	}
	215
66f592e2	216	static int proc_reconfigure(struct fs_context *fc)
97412950	217	{
66f592e2	218	struct super_block *sb = fc->root->d_sb;
fa10fed3	219	struct proc_fs_info *fs_info = proc_sb_info(sb);
02b9984d TT	220
02b9984d TT	221	sync_filesystem(sb);
66f592e2	222
fa10fed3	223	proc_apply_options(fs_info, fc, current_user_ns());
66f592e2	224	return 0;
97412950 VK	225	}
97412950 VK	226
66f592e2	227	static int proc_get_tree(struct fs_context *fc)
1da177e4	228	{
fa10fed3	229	return get_tree_nodev(fc, proc_fill_super);
66f592e2	230	}
07543f5c	231
66f592e2 DH	232	static void proc_fs_context_free(struct fs_context *fc)
	233	{
	234	struct proc_fs_context *ctx = fc->fs_private;
	235
46cf047a	236	put_pid_ns(ctx->pid_ns);
66f592e2 DH	237	kfree(ctx);
	238	}
	239
	240	static const struct fs_context_operations proc_fs_context_ops = {
	241	.free = proc_fs_context_free,
	242	.parse_param = proc_parse_param,
	243	.get_tree = proc_get_tree,
	244	.reconfigure = proc_reconfigure,
	245	};
	246
	247	static int proc_init_fs_context(struct fs_context *fc)
	248	{
	249	struct proc_fs_context *ctx;
	250
	251	ctx = kzalloc(sizeof(struct proc_fs_context), GFP_KERNEL);
	252	if (!ctx)
	253	return -ENOMEM;
07543f5c	254
66f592e2	255	ctx->pid_ns = get_pid_ns(task_active_pid_ns(current));
46cf047a AV	256	put_user_ns(fc->user_ns);
46cf047a AV	257	fc->user_ns = get_user_ns(ctx->pid_ns->user_ns);
66f592e2 DH	258	fc->fs_private = ctx;
	259	fc->ops = &proc_fs_context_ops;
	260	return 0;
07543f5c PE	261	}
	262
	263	static void proc_kill_sb(struct super_block *sb)
	264	{
fa10fed3	265	struct proc_fs_info *fs_info = proc_sb_info(sb);
07543f5c	266
058f2e4d AG	267	if (!fs_info) {
	268	kill_anon_super(sb);
	269	return;
	270	}
4fa3b1c4	271
058f2e4d AG	272	dput(fs_info->proc_self);
058f2e4d AG	273	dput(fs_info->proc_thread_self);
4fa3b1c4	274
fa10fed3 AG	275	kill_anon_super(sb);
	276	put_pid_ns(fs_info->pid_ns);
	277	kfree(fs_info);
1da177e4 LT	278	}
1da177e4 LT	279
c2319540	280	static struct file_system_type proc_fs_type = {
66f592e2 DH	281	.name = "proc",
66f592e2 DH	282	.init_fs_context = proc_init_fs_context,
d7167b14	283	.parameters = proc_fs_parameters,
66f592e2	284	.kill_sb = proc_kill_sb,
0b3b094a	285	.fs_flags = FS_USERNS_MOUNT \| FS_DISALLOW_NOTIFY_PERM,
1da177e4 LT	286	};
1da177e4 LT	287
1da177e4 LT	288	void __init proc_root_init(void)
1da177e4 LT	289	{
195b8cf0	290	proc_init_kmemcache();
1270dd8d	291	set_proc_pid_nlink();
e656d8a6	292	proc_self_init();
0097875b	293	proc_thread_self_init();
155134fe	294	proc_symlink("mounts", NULL, "self/mounts");
457c4cbc EB	295
457c4cbc EB	296	proc_net_init();
36a5aeb8	297	proc_mkdir("fs", NULL);
928b4d8c	298	proc_mkdir("driver", NULL);
eb6d38d5	299	proc_create_mount_point("fs/nfsd"); /* somewhere for the nfsd filesystem to be mounted */
1da177e4 LT	300	#if defined(CONFIG_SUN_OPENPROMFS) \|\| defined(CONFIG_SUN_OPENPROMFS_MODULE)
1da177e4 LT	301	/* just give it a mountpoint */
eb6d38d5	302	proc_create_mount_point("openprom");
1da177e4 LT	303	#endif
1da177e4 LT	304	proc_tty_init();
9c37066d	305	proc_mkdir("bus", NULL);
77b14db5	306	proc_sys_init();
1539d584 AD	307
1539d584 AD	308	register_filesystem(&proc_fs_type);
1da177e4 LT	309	}
1da177e4 LT	310
a528d35e DH	311	static int proc_root_getattr(const struct path path, struct kstat stat,
a528d35e DH	312	u32 request_mask, unsigned int query_flags)
1da177e4	313	{
0d56a451	314	generic_fillattr(&init_user_ns, d_inode(path->dentry), stat);
76b6159b AV	315	stat->nlink = proc_root.nlink + nr_processes();
	316	return 0;
	317	}
1da177e4	318
00cd8dd3	319	static struct dentry proc_root_lookup(struct inode dir, struct dentry * dentry, unsigned int flags)
76b6159b	320	{
867aaccf	321	if (!proc_pid_lookup(dentry, flags))
1da177e4	322	return NULL;
66f592e2	323
335eb531	324	return proc_lookup(dir, dentry, flags);
1da177e4 LT	325	}
1da177e4 LT	326
f0c3b509	327	static int proc_root_readdir(struct file file, struct dir_context ctx)
1da177e4	328	{
f0c3b509	329	if (ctx->pos < FIRST_PROCESS_ENTRY) {
94fc5d9d RG	330	int error = proc_readdir(file, ctx);
	331	if (unlikely(error <= 0))
	332	return error;
f0c3b509	333	ctx->pos = FIRST_PROCESS_ENTRY;
1da177e4	334	}
1da177e4	335
f0c3b509	336	return proc_pid_readdir(file, ctx);
1da177e4 LT	337	}
	338
	339	/*
	340	* The root /proc directory is special, as it has the
	341	* <pid> directories. Thus we don't use the generic
	342	* directory handling functions for that..
	343	*/
00977a59	344	static const struct file_operations proc_root_operations = {
1da177e4	345	.read = generic_read_dir,
f50752ea AV	346	.iterate_shared = proc_root_readdir,
f50752ea AV	347	.llseek = generic_file_llseek,
1da177e4 LT	348	};
	349
	350	/*
	351	* proc root can do almost nothing..
	352	*/
c5ef1c42	353	static const struct inode_operations proc_root_inode_operations = {
1da177e4	354	.lookup = proc_root_lookup,
76b6159b	355	.getattr = proc_root_getattr,
1da177e4 LT	356	};
	357
	358	/*
	359	* This is the root "inode" in the /proc tree..
	360	*/
	361	struct proc_dir_entry proc_root = {
	362	.low_ino = PROC_ROOT_INO,
	363	.namelen = 5,
1da177e4 LT	364	.mode = S_IFDIR \| S_IRUGO \| S_IXUGO,
1da177e4 LT	365	.nlink = 2,
9cdd83e3	366	.refcnt = REFCOUNT_INIT(1),
1da177e4	367	.proc_iops = &proc_root_inode_operations,
d56c0d45	368	.proc_dir_ops = &proc_root_operations,
1da177e4	369	.parent = &proc_root,
4f113437	370	.subdir = RB_ROOT,
24074a35	371	.name = "/proc",
1da177e4	372	};