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v6.2
  1// SPDX-License-Identifier: GPL-2.0
  2#include <linux/sched/signal.h>
  3#include <linux/errno.h>
  4#include <linux/dcache.h>
  5#include <linux/path.h>
  6#include <linux/fdtable.h>
  7#include <linux/namei.h>
  8#include <linux/pid.h>
  9#include <linux/ptrace.h>
 10#include <linux/bitmap.h>
 11#include <linux/security.h>
 12#include <linux/file.h>
 13#include <linux/seq_file.h>
 14#include <linux/fs.h>
 
 15
 16#include <linux/proc_fs.h>
 17
 18#include "../mount.h"
 19#include "internal.h"
 20#include "fd.h"
 21
 22static int seq_show(struct seq_file *m, void *v)
 23{
 24	struct files_struct *files = NULL;
 25	int f_flags = 0, ret = -ENOENT;
 26	struct file *file = NULL;
 27	struct task_struct *task;
 28
 29	task = get_proc_task(m->private);
 30	if (!task)
 31		return -ENOENT;
 32
 33	task_lock(task);
 34	files = task->files;
 35	if (files) {
 36		unsigned int fd = proc_fd(m->private);
 37
 38		spin_lock(&files->file_lock);
 39		file = files_lookup_fd_locked(files, fd);
 40		if (file) {
 41			struct fdtable *fdt = files_fdtable(files);
 42
 43			f_flags = file->f_flags;
 44			if (close_on_exec(fd, fdt))
 45				f_flags |= O_CLOEXEC;
 46
 47			get_file(file);
 48			ret = 0;
 49		}
 50		spin_unlock(&files->file_lock);
 51	}
 52	task_unlock(task);
 53	put_task_struct(task);
 54
 55	if (ret)
 56		return ret;
 57
 58	seq_printf(m, "pos:\t%lli\nflags:\t0%o\nmnt_id:\t%i\nino:\t%lu\n",
 59		   (long long)file->f_pos, f_flags,
 60		   real_mount(file->f_path.mnt)->mnt_id,
 61		   file_inode(file)->i_ino);
 62
 63	/* show_fd_locks() never deferences files so a stale value is safe */
 64	show_fd_locks(m, file, files);
 65	if (seq_has_overflowed(m))
 66		goto out;
 67
 68	if (file->f_op->show_fdinfo)
 69		file->f_op->show_fdinfo(m, file);
 70
 71out:
 72	fput(file);
 73	return 0;
 74}
 75
 76static int proc_fdinfo_access_allowed(struct inode *inode)
 77{
 78	bool allowed = false;
 79	struct task_struct *task = get_proc_task(inode);
 80
 81	if (!task)
 82		return -ESRCH;
 83
 84	allowed = ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS);
 85	put_task_struct(task);
 86
 87	if (!allowed)
 88		return -EACCES;
 89
 90	return 0;
 91}
 92
 93static int seq_fdinfo_open(struct inode *inode, struct file *file)
 94{
 95	int ret = proc_fdinfo_access_allowed(inode);
 96
 97	if (ret)
 98		return ret;
 99
100	return single_open(file, seq_show, inode);
101}
102
103static const struct file_operations proc_fdinfo_file_operations = {
104	.open		= seq_fdinfo_open,
105	.read		= seq_read,
106	.llseek		= seq_lseek,
107	.release	= single_release,
108};
109
110static bool tid_fd_mode(struct task_struct *task, unsigned fd, fmode_t *mode)
111{
112	struct file *file;
113
114	rcu_read_lock();
115	file = task_lookup_fd_rcu(task, fd);
116	if (file)
117		*mode = file->f_mode;
118	rcu_read_unlock();
 
 
 
 
119	return !!file;
120}
121
122static void tid_fd_update_inode(struct task_struct *task, struct inode *inode,
123				fmode_t f_mode)
124{
125	task_dump_owner(task, 0, &inode->i_uid, &inode->i_gid);
126
127	if (S_ISLNK(inode->i_mode)) {
128		unsigned i_mode = S_IFLNK;
129		if (f_mode & FMODE_READ)
130			i_mode |= S_IRUSR | S_IXUSR;
131		if (f_mode & FMODE_WRITE)
132			i_mode |= S_IWUSR | S_IXUSR;
133		inode->i_mode = i_mode;
134	}
135	security_task_to_inode(task, inode);
136}
137
138static int tid_fd_revalidate(struct dentry *dentry, unsigned int flags)
139{
140	struct task_struct *task;
141	struct inode *inode;
142	unsigned int fd;
143
144	if (flags & LOOKUP_RCU)
145		return -ECHILD;
146
147	inode = d_inode(dentry);
148	task = get_proc_task(inode);
149	fd = proc_fd(inode);
150
151	if (task) {
152		fmode_t f_mode;
153		if (tid_fd_mode(task, fd, &f_mode)) {
154			tid_fd_update_inode(task, inode, f_mode);
155			put_task_struct(task);
156			return 1;
157		}
158		put_task_struct(task);
159	}
160	return 0;
161}
162
163static const struct dentry_operations tid_fd_dentry_operations = {
164	.d_revalidate	= tid_fd_revalidate,
165	.d_delete	= pid_delete_dentry,
166};
167
168static int proc_fd_link(struct dentry *dentry, struct path *path)
169{
170	struct task_struct *task;
171	int ret = -ENOENT;
172
173	task = get_proc_task(d_inode(dentry));
174	if (task) {
175		unsigned int fd = proc_fd(d_inode(dentry));
176		struct file *fd_file;
177
178		fd_file = fget_task(task, fd);
179		if (fd_file) {
180			*path = fd_file->f_path;
181			path_get(&fd_file->f_path);
182			ret = 0;
183			fput(fd_file);
184		}
185		put_task_struct(task);
186	}
187
188	return ret;
189}
190
191struct fd_data {
192	fmode_t mode;
193	unsigned fd;
194};
195
196static struct dentry *proc_fd_instantiate(struct dentry *dentry,
197	struct task_struct *task, const void *ptr)
198{
199	const struct fd_data *data = ptr;
200	struct proc_inode *ei;
201	struct inode *inode;
202
203	inode = proc_pid_make_inode(dentry->d_sb, task, S_IFLNK);
204	if (!inode)
205		return ERR_PTR(-ENOENT);
206
207	ei = PROC_I(inode);
208	ei->fd = data->fd;
209
210	inode->i_op = &proc_pid_link_inode_operations;
211	inode->i_size = 64;
212
213	ei->op.proc_get_link = proc_fd_link;
214	tid_fd_update_inode(task, inode, data->mode);
215
216	d_set_d_op(dentry, &tid_fd_dentry_operations);
217	return d_splice_alias(inode, dentry);
218}
219
220static struct dentry *proc_lookupfd_common(struct inode *dir,
221					   struct dentry *dentry,
222					   instantiate_t instantiate)
223{
224	struct task_struct *task = get_proc_task(dir);
225	struct fd_data data = {.fd = name_to_int(&dentry->d_name)};
226	struct dentry *result = ERR_PTR(-ENOENT);
227
228	if (!task)
229		goto out_no_task;
230	if (data.fd == ~0U)
231		goto out;
232	if (!tid_fd_mode(task, data.fd, &data.mode))
233		goto out;
234
235	result = instantiate(dentry, task, &data);
236out:
237	put_task_struct(task);
238out_no_task:
239	return result;
240}
241
242static int proc_readfd_common(struct file *file, struct dir_context *ctx,
243			      instantiate_t instantiate)
244{
245	struct task_struct *p = get_proc_task(file_inode(file));
246	unsigned int fd;
247
248	if (!p)
249		return -ENOENT;
250
251	if (!dir_emit_dots(file, ctx))
252		goto out;
253
254	rcu_read_lock();
255	for (fd = ctx->pos - 2;; fd++) {
256		struct file *f;
257		struct fd_data data;
258		char name[10 + 1];
259		unsigned int len;
260
261		f = task_lookup_next_fd_rcu(p, &fd);
262		ctx->pos = fd + 2LL;
263		if (!f)
264			break;
265		data.mode = f->f_mode;
266		rcu_read_unlock();
 
267		data.fd = fd;
268
269		len = snprintf(name, sizeof(name), "%u", fd);
270		if (!proc_fill_cache(file, ctx,
271				     name, len, instantiate, p,
272				     &data))
273			goto out;
274		cond_resched();
275		rcu_read_lock();
276	}
277	rcu_read_unlock();
278out:
279	put_task_struct(p);
280	return 0;
281}
282
283static int proc_readfd_count(struct inode *inode, loff_t *count)
284{
285	struct task_struct *p = get_proc_task(inode);
286	struct fdtable *fdt;
287
288	if (!p)
289		return -ENOENT;
290
291	task_lock(p);
292	if (p->files) {
293		rcu_read_lock();
294
295		fdt = files_fdtable(p->files);
296		*count = bitmap_weight(fdt->open_fds, fdt->max_fds);
297
298		rcu_read_unlock();
299	}
300	task_unlock(p);
301
302	put_task_struct(p);
303
304	return 0;
305}
306
307static int proc_readfd(struct file *file, struct dir_context *ctx)
308{
309	return proc_readfd_common(file, ctx, proc_fd_instantiate);
310}
311
312const struct file_operations proc_fd_operations = {
313	.read		= generic_read_dir,
314	.iterate_shared	= proc_readfd,
315	.llseek		= generic_file_llseek,
316};
317
318static struct dentry *proc_lookupfd(struct inode *dir, struct dentry *dentry,
319				    unsigned int flags)
320{
321	return proc_lookupfd_common(dir, dentry, proc_fd_instantiate);
322}
323
324/*
325 * /proc/pid/fd needs a special permission handler so that a process can still
326 * access /proc/self/fd after it has executed a setuid().
327 */
328int proc_fd_permission(struct user_namespace *mnt_userns,
329		       struct inode *inode, int mask)
330{
331	struct task_struct *p;
332	int rv;
333
334	rv = generic_permission(&init_user_ns, inode, mask);
335	if (rv == 0)
336		return rv;
337
338	rcu_read_lock();
339	p = pid_task(proc_pid(inode), PIDTYPE_PID);
340	if (p && same_thread_group(p, current))
341		rv = 0;
342	rcu_read_unlock();
343
344	return rv;
345}
346
347static int proc_fd_getattr(struct user_namespace *mnt_userns,
348			const struct path *path, struct kstat *stat,
349			u32 request_mask, unsigned int query_flags)
350{
351	struct inode *inode = d_inode(path->dentry);
352	int rv = 0;
353
354	generic_fillattr(&init_user_ns, inode, stat);
355
356	/* If it's a directory, put the number of open fds there */
357	if (S_ISDIR(inode->i_mode)) {
358		rv = proc_readfd_count(inode, &stat->size);
359		if (rv < 0)
360			return rv;
361	}
362
363	return rv;
364}
365
366const struct inode_operations proc_fd_inode_operations = {
367	.lookup		= proc_lookupfd,
368	.permission	= proc_fd_permission,
369	.getattr	= proc_fd_getattr,
370	.setattr	= proc_setattr,
371};
372
373static struct dentry *proc_fdinfo_instantiate(struct dentry *dentry,
374	struct task_struct *task, const void *ptr)
375{
376	const struct fd_data *data = ptr;
377	struct proc_inode *ei;
378	struct inode *inode;
379
380	inode = proc_pid_make_inode(dentry->d_sb, task, S_IFREG | S_IRUGO);
381	if (!inode)
382		return ERR_PTR(-ENOENT);
383
384	ei = PROC_I(inode);
385	ei->fd = data->fd;
386
387	inode->i_fop = &proc_fdinfo_file_operations;
388	tid_fd_update_inode(task, inode, 0);
389
390	d_set_d_op(dentry, &tid_fd_dentry_operations);
391	return d_splice_alias(inode, dentry);
392}
393
394static struct dentry *
395proc_lookupfdinfo(struct inode *dir, struct dentry *dentry, unsigned int flags)
396{
397	return proc_lookupfd_common(dir, dentry, proc_fdinfo_instantiate);
398}
399
400static int proc_readfdinfo(struct file *file, struct dir_context *ctx)
401{
402	return proc_readfd_common(file, ctx,
403				  proc_fdinfo_instantiate);
404}
405
406static int proc_open_fdinfo(struct inode *inode, struct file *file)
407{
408	int ret = proc_fdinfo_access_allowed(inode);
409
410	if (ret)
411		return ret;
412
413	return 0;
414}
415
416const struct inode_operations proc_fdinfo_inode_operations = {
417	.lookup		= proc_lookupfdinfo,
418	.setattr	= proc_setattr,
419};
420
421const struct file_operations proc_fdinfo_operations = {
422	.open		= proc_open_fdinfo,
423	.read		= generic_read_dir,
424	.iterate_shared	= proc_readfdinfo,
425	.llseek		= generic_file_llseek,
426};
v6.8
  1// SPDX-License-Identifier: GPL-2.0
  2#include <linux/sched/signal.h>
  3#include <linux/errno.h>
  4#include <linux/dcache.h>
  5#include <linux/path.h>
  6#include <linux/fdtable.h>
  7#include <linux/namei.h>
  8#include <linux/pid.h>
  9#include <linux/ptrace.h>
 10#include <linux/bitmap.h>
 11#include <linux/security.h>
 12#include <linux/file.h>
 13#include <linux/seq_file.h>
 14#include <linux/fs.h>
 15#include <linux/filelock.h>
 16
 17#include <linux/proc_fs.h>
 18
 19#include "../mount.h"
 20#include "internal.h"
 21#include "fd.h"
 22
 23static int seq_show(struct seq_file *m, void *v)
 24{
 25	struct files_struct *files = NULL;
 26	int f_flags = 0, ret = -ENOENT;
 27	struct file *file = NULL;
 28	struct task_struct *task;
 29
 30	task = get_proc_task(m->private);
 31	if (!task)
 32		return -ENOENT;
 33
 34	task_lock(task);
 35	files = task->files;
 36	if (files) {
 37		unsigned int fd = proc_fd(m->private);
 38
 39		spin_lock(&files->file_lock);
 40		file = files_lookup_fd_locked(files, fd);
 41		if (file) {
 42			struct fdtable *fdt = files_fdtable(files);
 43
 44			f_flags = file->f_flags;
 45			if (close_on_exec(fd, fdt))
 46				f_flags |= O_CLOEXEC;
 47
 48			get_file(file);
 49			ret = 0;
 50		}
 51		spin_unlock(&files->file_lock);
 52	}
 53	task_unlock(task);
 54	put_task_struct(task);
 55
 56	if (ret)
 57		return ret;
 58
 59	seq_printf(m, "pos:\t%lli\nflags:\t0%o\nmnt_id:\t%i\nino:\t%lu\n",
 60		   (long long)file->f_pos, f_flags,
 61		   real_mount(file->f_path.mnt)->mnt_id,
 62		   file_inode(file)->i_ino);
 63
 64	/* show_fd_locks() never deferences files so a stale value is safe */
 65	show_fd_locks(m, file, files);
 66	if (seq_has_overflowed(m))
 67		goto out;
 68
 69	if (file->f_op->show_fdinfo)
 70		file->f_op->show_fdinfo(m, file);
 71
 72out:
 73	fput(file);
 74	return 0;
 75}
 76
 77static int proc_fdinfo_access_allowed(struct inode *inode)
 78{
 79	bool allowed = false;
 80	struct task_struct *task = get_proc_task(inode);
 81
 82	if (!task)
 83		return -ESRCH;
 84
 85	allowed = ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS);
 86	put_task_struct(task);
 87
 88	if (!allowed)
 89		return -EACCES;
 90
 91	return 0;
 92}
 93
 94static int seq_fdinfo_open(struct inode *inode, struct file *file)
 95{
 96	int ret = proc_fdinfo_access_allowed(inode);
 97
 98	if (ret)
 99		return ret;
100
101	return single_open(file, seq_show, inode);
102}
103
104static const struct file_operations proc_fdinfo_file_operations = {
105	.open		= seq_fdinfo_open,
106	.read		= seq_read,
107	.llseek		= seq_lseek,
108	.release	= single_release,
109};
110
111static bool tid_fd_mode(struct task_struct *task, unsigned fd, fmode_t *mode)
112{
113	struct file *file;
114
115	rcu_read_lock();
116	file = task_lookup_fdget_rcu(task, fd);
 
 
117	rcu_read_unlock();
118	if (file) {
119		*mode = file->f_mode;
120		fput(file);
121	}
122	return !!file;
123}
124
125static void tid_fd_update_inode(struct task_struct *task, struct inode *inode,
126				fmode_t f_mode)
127{
128	task_dump_owner(task, 0, &inode->i_uid, &inode->i_gid);
129
130	if (S_ISLNK(inode->i_mode)) {
131		unsigned i_mode = S_IFLNK;
132		if (f_mode & FMODE_READ)
133			i_mode |= S_IRUSR | S_IXUSR;
134		if (f_mode & FMODE_WRITE)
135			i_mode |= S_IWUSR | S_IXUSR;
136		inode->i_mode = i_mode;
137	}
138	security_task_to_inode(task, inode);
139}
140
141static int tid_fd_revalidate(struct dentry *dentry, unsigned int flags)
142{
143	struct task_struct *task;
144	struct inode *inode;
145	unsigned int fd;
146
147	if (flags & LOOKUP_RCU)
148		return -ECHILD;
149
150	inode = d_inode(dentry);
151	task = get_proc_task(inode);
152	fd = proc_fd(inode);
153
154	if (task) {
155		fmode_t f_mode;
156		if (tid_fd_mode(task, fd, &f_mode)) {
157			tid_fd_update_inode(task, inode, f_mode);
158			put_task_struct(task);
159			return 1;
160		}
161		put_task_struct(task);
162	}
163	return 0;
164}
165
166static const struct dentry_operations tid_fd_dentry_operations = {
167	.d_revalidate	= tid_fd_revalidate,
168	.d_delete	= pid_delete_dentry,
169};
170
171static int proc_fd_link(struct dentry *dentry, struct path *path)
172{
173	struct task_struct *task;
174	int ret = -ENOENT;
175
176	task = get_proc_task(d_inode(dentry));
177	if (task) {
178		unsigned int fd = proc_fd(d_inode(dentry));
179		struct file *fd_file;
180
181		fd_file = fget_task(task, fd);
182		if (fd_file) {
183			*path = fd_file->f_path;
184			path_get(&fd_file->f_path);
185			ret = 0;
186			fput(fd_file);
187		}
188		put_task_struct(task);
189	}
190
191	return ret;
192}
193
194struct fd_data {
195	fmode_t mode;
196	unsigned fd;
197};
198
199static struct dentry *proc_fd_instantiate(struct dentry *dentry,
200	struct task_struct *task, const void *ptr)
201{
202	const struct fd_data *data = ptr;
203	struct proc_inode *ei;
204	struct inode *inode;
205
206	inode = proc_pid_make_inode(dentry->d_sb, task, S_IFLNK);
207	if (!inode)
208		return ERR_PTR(-ENOENT);
209
210	ei = PROC_I(inode);
211	ei->fd = data->fd;
212
213	inode->i_op = &proc_pid_link_inode_operations;
214	inode->i_size = 64;
215
216	ei->op.proc_get_link = proc_fd_link;
217	tid_fd_update_inode(task, inode, data->mode);
218
219	d_set_d_op(dentry, &tid_fd_dentry_operations);
220	return d_splice_alias(inode, dentry);
221}
222
223static struct dentry *proc_lookupfd_common(struct inode *dir,
224					   struct dentry *dentry,
225					   instantiate_t instantiate)
226{
227	struct task_struct *task = get_proc_task(dir);
228	struct fd_data data = {.fd = name_to_int(&dentry->d_name)};
229	struct dentry *result = ERR_PTR(-ENOENT);
230
231	if (!task)
232		goto out_no_task;
233	if (data.fd == ~0U)
234		goto out;
235	if (!tid_fd_mode(task, data.fd, &data.mode))
236		goto out;
237
238	result = instantiate(dentry, task, &data);
239out:
240	put_task_struct(task);
241out_no_task:
242	return result;
243}
244
245static int proc_readfd_common(struct file *file, struct dir_context *ctx,
246			      instantiate_t instantiate)
247{
248	struct task_struct *p = get_proc_task(file_inode(file));
249	unsigned int fd;
250
251	if (!p)
252		return -ENOENT;
253
254	if (!dir_emit_dots(file, ctx))
255		goto out;
256
257	rcu_read_lock();
258	for (fd = ctx->pos - 2;; fd++) {
259		struct file *f;
260		struct fd_data data;
261		char name[10 + 1];
262		unsigned int len;
263
264		f = task_lookup_next_fdget_rcu(p, &fd);
265		ctx->pos = fd + 2LL;
266		if (!f)
267			break;
268		data.mode = f->f_mode;
269		rcu_read_unlock();
270		fput(f);
271		data.fd = fd;
272
273		len = snprintf(name, sizeof(name), "%u", fd);
274		if (!proc_fill_cache(file, ctx,
275				     name, len, instantiate, p,
276				     &data))
277			goto out;
278		cond_resched();
279		rcu_read_lock();
280	}
281	rcu_read_unlock();
282out:
283	put_task_struct(p);
284	return 0;
285}
286
287static int proc_readfd_count(struct inode *inode, loff_t *count)
288{
289	struct task_struct *p = get_proc_task(inode);
290	struct fdtable *fdt;
291
292	if (!p)
293		return -ENOENT;
294
295	task_lock(p);
296	if (p->files) {
297		rcu_read_lock();
298
299		fdt = files_fdtable(p->files);
300		*count = bitmap_weight(fdt->open_fds, fdt->max_fds);
301
302		rcu_read_unlock();
303	}
304	task_unlock(p);
305
306	put_task_struct(p);
307
308	return 0;
309}
310
311static int proc_readfd(struct file *file, struct dir_context *ctx)
312{
313	return proc_readfd_common(file, ctx, proc_fd_instantiate);
314}
315
316const struct file_operations proc_fd_operations = {
317	.read		= generic_read_dir,
318	.iterate_shared	= proc_readfd,
319	.llseek		= generic_file_llseek,
320};
321
322static struct dentry *proc_lookupfd(struct inode *dir, struct dentry *dentry,
323				    unsigned int flags)
324{
325	return proc_lookupfd_common(dir, dentry, proc_fd_instantiate);
326}
327
328/*
329 * /proc/pid/fd needs a special permission handler so that a process can still
330 * access /proc/self/fd after it has executed a setuid().
331 */
332int proc_fd_permission(struct mnt_idmap *idmap,
333		       struct inode *inode, int mask)
334{
335	struct task_struct *p;
336	int rv;
337
338	rv = generic_permission(&nop_mnt_idmap, inode, mask);
339	if (rv == 0)
340		return rv;
341
342	rcu_read_lock();
343	p = pid_task(proc_pid(inode), PIDTYPE_PID);
344	if (p && same_thread_group(p, current))
345		rv = 0;
346	rcu_read_unlock();
347
348	return rv;
349}
350
351static int proc_fd_getattr(struct mnt_idmap *idmap,
352			const struct path *path, struct kstat *stat,
353			u32 request_mask, unsigned int query_flags)
354{
355	struct inode *inode = d_inode(path->dentry);
356	int rv = 0;
357
358	generic_fillattr(&nop_mnt_idmap, request_mask, inode, stat);
359
360	/* If it's a directory, put the number of open fds there */
361	if (S_ISDIR(inode->i_mode)) {
362		rv = proc_readfd_count(inode, &stat->size);
363		if (rv < 0)
364			return rv;
365	}
366
367	return rv;
368}
369
370const struct inode_operations proc_fd_inode_operations = {
371	.lookup		= proc_lookupfd,
372	.permission	= proc_fd_permission,
373	.getattr	= proc_fd_getattr,
374	.setattr	= proc_setattr,
375};
376
377static struct dentry *proc_fdinfo_instantiate(struct dentry *dentry,
378	struct task_struct *task, const void *ptr)
379{
380	const struct fd_data *data = ptr;
381	struct proc_inode *ei;
382	struct inode *inode;
383
384	inode = proc_pid_make_inode(dentry->d_sb, task, S_IFREG | S_IRUGO);
385	if (!inode)
386		return ERR_PTR(-ENOENT);
387
388	ei = PROC_I(inode);
389	ei->fd = data->fd;
390
391	inode->i_fop = &proc_fdinfo_file_operations;
392	tid_fd_update_inode(task, inode, 0);
393
394	d_set_d_op(dentry, &tid_fd_dentry_operations);
395	return d_splice_alias(inode, dentry);
396}
397
398static struct dentry *
399proc_lookupfdinfo(struct inode *dir, struct dentry *dentry, unsigned int flags)
400{
401	return proc_lookupfd_common(dir, dentry, proc_fdinfo_instantiate);
402}
403
404static int proc_readfdinfo(struct file *file, struct dir_context *ctx)
405{
406	return proc_readfd_common(file, ctx,
407				  proc_fdinfo_instantiate);
408}
409
410static int proc_open_fdinfo(struct inode *inode, struct file *file)
411{
412	int ret = proc_fdinfo_access_allowed(inode);
413
414	if (ret)
415		return ret;
416
417	return 0;
418}
419
420const struct inode_operations proc_fdinfo_inode_operations = {
421	.lookup		= proc_lookupfdinfo,
422	.setattr	= proc_setattr,
423};
424
425const struct file_operations proc_fdinfo_operations = {
426	.open		= proc_open_fdinfo,
427	.read		= generic_read_dir,
428	.iterate_shared	= proc_readfdinfo,
429	.llseek		= generic_file_llseek,
430};