1#include <linux/sched.h>
2#include <linux/errno.h>
3#include <linux/dcache.h>
4#include <linux/path.h>
5#include <linux/fdtable.h>
6#include <linux/namei.h>
7#include <linux/pid.h>
8#include <linux/security.h>
9#include <linux/file.h>
10#include <linux/seq_file.h>
11
12#include <linux/proc_fs.h>
13
14#include "internal.h"
15#include "fd.h"
16
17static int seq_show(struct seq_file *m, void *v)
18{
19 struct files_struct *files = NULL;
20 int f_flags = 0, ret = -ENOENT;
21 struct file *file = NULL;
22 struct task_struct *task;
23
24 task = get_proc_task(m->private);
25 if (!task)
26 return -ENOENT;
27
28 files = get_files_struct(task);
29 put_task_struct(task);
30
31 if (files) {
32 int fd = proc_fd(m->private);
33
34 spin_lock(&files->file_lock);
35 file = fcheck_files(files, fd);
36 if (file) {
37 struct fdtable *fdt = files_fdtable(files);
38
39 f_flags = file->f_flags;
40 if (close_on_exec(fd, fdt))
41 f_flags |= O_CLOEXEC;
42
43 get_file(file);
44 ret = 0;
45 }
46 spin_unlock(&files->file_lock);
47 put_files_struct(files);
48 }
49
50 if (!ret) {
51 seq_printf(m, "pos:\t%lli\nflags:\t0%o\n",
52 (long long)file->f_pos, f_flags);
53 if (file->f_op->show_fdinfo)
54 ret = file->f_op->show_fdinfo(m, file);
55 fput(file);
56 }
57
58 return ret;
59}
60
61static int seq_fdinfo_open(struct inode *inode, struct file *file)
62{
63 return single_open(file, seq_show, inode);
64}
65
66static const struct file_operations proc_fdinfo_file_operations = {
67 .open = seq_fdinfo_open,
68 .read = seq_read,
69 .llseek = seq_lseek,
70 .release = single_release,
71};
72
73static int tid_fd_revalidate(struct dentry *dentry, unsigned int flags)
74{
75 struct files_struct *files;
76 struct task_struct *task;
77 const struct cred *cred;
78 struct inode *inode;
79 int fd;
80
81 if (flags & LOOKUP_RCU)
82 return -ECHILD;
83
84 inode = dentry->d_inode;
85 task = get_proc_task(inode);
86 fd = proc_fd(inode);
87
88 if (task) {
89 files = get_files_struct(task);
90 if (files) {
91 struct file *file;
92
93 rcu_read_lock();
94 file = fcheck_files(files, fd);
95 if (file) {
96 unsigned f_mode = file->f_mode;
97
98 rcu_read_unlock();
99 put_files_struct(files);
100
101 if (task_dumpable(task)) {
102 rcu_read_lock();
103 cred = __task_cred(task);
104 inode->i_uid = cred->euid;
105 inode->i_gid = cred->egid;
106 rcu_read_unlock();
107 } else {
108 inode->i_uid = GLOBAL_ROOT_UID;
109 inode->i_gid = GLOBAL_ROOT_GID;
110 }
111
112 if (S_ISLNK(inode->i_mode)) {
113 unsigned i_mode = S_IFLNK;
114 if (f_mode & FMODE_READ)
115 i_mode |= S_IRUSR | S_IXUSR;
116 if (f_mode & FMODE_WRITE)
117 i_mode |= S_IWUSR | S_IXUSR;
118 inode->i_mode = i_mode;
119 }
120
121 security_task_to_inode(task, inode);
122 put_task_struct(task);
123 return 1;
124 }
125 rcu_read_unlock();
126 put_files_struct(files);
127 }
128 put_task_struct(task);
129 }
130
131 d_drop(dentry);
132 return 0;
133}
134
135static const struct dentry_operations tid_fd_dentry_operations = {
136 .d_revalidate = tid_fd_revalidate,
137 .d_delete = pid_delete_dentry,
138};
139
140static int proc_fd_link(struct dentry *dentry, struct path *path)
141{
142 struct files_struct *files = NULL;
143 struct task_struct *task;
144 int ret = -ENOENT;
145
146 task = get_proc_task(dentry->d_inode);
147 if (task) {
148 files = get_files_struct(task);
149 put_task_struct(task);
150 }
151
152 if (files) {
153 int fd = proc_fd(dentry->d_inode);
154 struct file *fd_file;
155
156 spin_lock(&files->file_lock);
157 fd_file = fcheck_files(files, fd);
158 if (fd_file) {
159 *path = fd_file->f_path;
160 path_get(&fd_file->f_path);
161 ret = 0;
162 }
163 spin_unlock(&files->file_lock);
164 put_files_struct(files);
165 }
166
167 return ret;
168}
169
170static struct dentry *
171proc_fd_instantiate(struct inode *dir, struct dentry *dentry,
172 struct task_struct *task, const void *ptr)
173{
174 struct dentry *error = ERR_PTR(-ENOENT);
175 unsigned fd = (unsigned long)ptr;
176 struct proc_inode *ei;
177 struct inode *inode;
178
179 inode = proc_pid_make_inode(dir->i_sb, task);
180 if (!inode)
181 goto out;
182
183 ei = PROC_I(inode);
184 ei->fd = fd;
185
186 inode->i_mode = S_IFLNK;
187 inode->i_op = &proc_pid_link_inode_operations;
188 inode->i_size = 64;
189
190 ei->op.proc_get_link = proc_fd_link;
191
192 d_set_d_op(dentry, &tid_fd_dentry_operations);
193 d_add(dentry, inode);
194
195
196 if (tid_fd_revalidate(dentry, 0))
197 error = NULL;
198 out:
199 return error;
200}
201
202static struct dentry *proc_lookupfd_common(struct inode *dir,
203 struct dentry *dentry,
204 instantiate_t instantiate)
205{
206 struct task_struct *task = get_proc_task(dir);
207 struct dentry *result = ERR_PTR(-ENOENT);
208 unsigned fd = name_to_int(dentry);
209
210 if (!task)
211 goto out_no_task;
212 if (fd == ~0U)
213 goto out;
214
215 result = instantiate(dir, dentry, task, (void *)(unsigned long)fd);
216out:
217 put_task_struct(task);
218out_no_task:
219 return result;
220}
221
222static int proc_readfd_common(struct file * filp, void * dirent,
223 filldir_t filldir, instantiate_t instantiate)
224{
225 struct dentry *dentry = filp->f_path.dentry;
226 struct inode *inode = dentry->d_inode;
227 struct task_struct *p = get_proc_task(inode);
228 struct files_struct *files;
229 unsigned int fd, ino;
230 int retval;
231
232 retval = -ENOENT;
233 if (!p)
234 goto out_no_task;
235 retval = 0;
236
237 fd = filp->f_pos;
238 switch (fd) {
239 case 0:
240 if (filldir(dirent, ".", 1, 0, inode->i_ino, DT_DIR) < 0)
241 goto out;
242 filp->f_pos++;
243 case 1:
244 ino = parent_ino(dentry);
245 if (filldir(dirent, "..", 2, 1, ino, DT_DIR) < 0)
246 goto out;
247 filp->f_pos++;
248 default:
249 files = get_files_struct(p);
250 if (!files)
251 goto out;
252 rcu_read_lock();
253 for (fd = filp->f_pos - 2;
254 fd < files_fdtable(files)->max_fds;
255 fd++, filp->f_pos++) {
256 char name[PROC_NUMBUF];
257 int len;
258 int rv;
259
260 if (!fcheck_files(files, fd))
261 continue;
262 rcu_read_unlock();
263
264 len = snprintf(name, sizeof(name), "%d", fd);
265 rv = proc_fill_cache(filp, dirent, filldir,
266 name, len, instantiate, p,
267 (void *)(unsigned long)fd);
268 if (rv < 0)
269 goto out_fd_loop;
270 rcu_read_lock();
271 }
272 rcu_read_unlock();
273out_fd_loop:
274 put_files_struct(files);
275 }
276out:
277 put_task_struct(p);
278out_no_task:
279 return retval;
280}
281
282static int proc_readfd(struct file *filp, void *dirent, filldir_t filldir)
283{
284 return proc_readfd_common(filp, dirent, filldir, proc_fd_instantiate);
285}
286
287const struct file_operations proc_fd_operations = {
288 .read = generic_read_dir,
289 .readdir = proc_readfd,
290 .llseek = default_llseek,
291};
292
293static struct dentry *proc_lookupfd(struct inode *dir, struct dentry *dentry,
294 unsigned int flags)
295{
296 return proc_lookupfd_common(dir, dentry, proc_fd_instantiate);
297}
298
299
300
301
302
303int proc_fd_permission(struct inode *inode, int mask)
304{
305 int rv = generic_permission(inode, mask);
306 if (rv == 0)
307 return 0;
308 if (task_pid(current) == proc_pid(inode))
309 rv = 0;
310 return rv;
311}
312
313const struct inode_operations proc_fd_inode_operations = {
314 .lookup = proc_lookupfd,
315 .permission = proc_fd_permission,
316 .setattr = proc_setattr,
317};
318
319static struct dentry *
320proc_fdinfo_instantiate(struct inode *dir, struct dentry *dentry,
321 struct task_struct *task, const void *ptr)
322{
323 struct dentry *error = ERR_PTR(-ENOENT);
324 unsigned fd = (unsigned long)ptr;
325 struct proc_inode *ei;
326 struct inode *inode;
327
328 inode = proc_pid_make_inode(dir->i_sb, task);
329 if (!inode)
330 goto out;
331
332 ei = PROC_I(inode);
333 ei->fd = fd;
334
335 inode->i_mode = S_IFREG | S_IRUSR;
336 inode->i_fop = &proc_fdinfo_file_operations;
337
338 d_set_d_op(dentry, &tid_fd_dentry_operations);
339 d_add(dentry, inode);
340
341
342 if (tid_fd_revalidate(dentry, 0))
343 error = NULL;
344 out:
345 return error;
346}
347
348static struct dentry *
349proc_lookupfdinfo(struct inode *dir, struct dentry *dentry, unsigned int flags)
350{
351 return proc_lookupfd_common(dir, dentry, proc_fdinfo_instantiate);
352}
353
354static int proc_readfdinfo(struct file *filp, void *dirent, filldir_t filldir)
355{
356 return proc_readfd_common(filp, dirent, filldir,
357 proc_fdinfo_instantiate);
358}
359
360const struct inode_operations proc_fdinfo_inode_operations = {
361 .lookup = proc_lookupfdinfo,
362 .setattr = proc_setattr,
363};
364
365const struct file_operations proc_fdinfo_operations = {
366 .read = generic_read_dir,
367 .readdir = proc_readfdinfo,
368 .llseek = default_llseek,
369};
370
