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 int
171proc_fd_instantiate(struct inode *dir, struct dentry *dentry,
172 struct task_struct *task, const void *ptr)
173{
174 unsigned fd = (unsigned long)ptr;
175 struct proc_inode *ei;
176 struct inode *inode;
177
178 inode = proc_pid_make_inode(dir->i_sb, task);
179 if (!inode)
180 goto out;
181
182 ei = PROC_I(inode);
183 ei->fd = fd;
184
185 inode->i_mode = S_IFLNK;
186 inode->i_op = &proc_pid_link_inode_operations;
187 inode->i_size = 64;
188
189 ei->op.proc_get_link = proc_fd_link;
190
191 d_set_d_op(dentry, &tid_fd_dentry_operations);
192 d_add(dentry, inode);
193
194
195 if (tid_fd_revalidate(dentry, 0))
196 return 0;
197 out:
198 return -ENOENT;
199}
200
201static struct dentry *proc_lookupfd_common(struct inode *dir,
202 struct dentry *dentry,
203 instantiate_t instantiate)
204{
205 struct task_struct *task = get_proc_task(dir);
206 int result = -ENOENT;
207 unsigned fd = name_to_int(dentry);
208
209 if (!task)
210 goto out_no_task;
211 if (fd == ~0U)
212 goto out;
213
214 result = instantiate(dir, dentry, task, (void *)(unsigned long)fd);
215out:
216 put_task_struct(task);
217out_no_task:
218 return ERR_PTR(result);
219}
220
221static int proc_readfd_common(struct file *file, struct dir_context *ctx,
222 instantiate_t instantiate)
223{
224 struct task_struct *p = get_proc_task(file_inode(file));
225 struct files_struct *files;
226 unsigned int fd;
227
228 if (!p)
229 return -ENOENT;
230
231 if (!dir_emit_dots(file, ctx))
232 goto out;
233 files = get_files_struct(p);
234 if (!files)
235 goto out;
236
237 rcu_read_lock();
238 for (fd = ctx->pos - 2;
239 fd < files_fdtable(files)->max_fds;
240 fd++, ctx->pos++) {
241 char name[PROC_NUMBUF];
242 int len;
243
244 if (!fcheck_files(files, fd))
245 continue;
246 rcu_read_unlock();
247
248 len = snprintf(name, sizeof(name), "%d", fd);
249 if (!proc_fill_cache(file, ctx,
250 name, len, instantiate, p,
251 (void *)(unsigned long)fd))
252 goto out_fd_loop;
253 rcu_read_lock();
254 }
255 rcu_read_unlock();
256out_fd_loop:
257 put_files_struct(files);
258out:
259 put_task_struct(p);
260 return 0;
261}
262
263static int proc_readfd(struct file *file, struct dir_context *ctx)
264{
265 return proc_readfd_common(file, ctx, proc_fd_instantiate);
266}
267
268const struct file_operations proc_fd_operations = {
269 .read = generic_read_dir,
270 .iterate = proc_readfd,
271 .llseek = default_llseek,
272};
273
274static struct dentry *proc_lookupfd(struct inode *dir, struct dentry *dentry,
275 unsigned int flags)
276{
277 return proc_lookupfd_common(dir, dentry, proc_fd_instantiate);
278}
279
280
281
282
283
284int proc_fd_permission(struct inode *inode, int mask)
285{
286 int rv = generic_permission(inode, mask);
287 if (rv == 0)
288 return 0;
289 if (task_tgid(current) == proc_pid(inode))
290 rv = 0;
291 return rv;
292}
293
294const struct inode_operations proc_fd_inode_operations = {
295 .lookup = proc_lookupfd,
296 .permission = proc_fd_permission,
297 .setattr = proc_setattr,
298};
299
300static int
301proc_fdinfo_instantiate(struct inode *dir, struct dentry *dentry,
302 struct task_struct *task, const void *ptr)
303{
304 unsigned fd = (unsigned long)ptr;
305 struct proc_inode *ei;
306 struct inode *inode;
307
308 inode = proc_pid_make_inode(dir->i_sb, task);
309 if (!inode)
310 goto out;
311
312 ei = PROC_I(inode);
313 ei->fd = fd;
314
315 inode->i_mode = S_IFREG | S_IRUSR;
316 inode->i_fop = &proc_fdinfo_file_operations;
317
318 d_set_d_op(dentry, &tid_fd_dentry_operations);
319 d_add(dentry, inode);
320
321
322 if (tid_fd_revalidate(dentry, 0))
323 return 0;
324 out:
325 return -ENOENT;
326}
327
328static struct dentry *
329proc_lookupfdinfo(struct inode *dir, struct dentry *dentry, unsigned int flags)
330{
331 return proc_lookupfd_common(dir, dentry, proc_fdinfo_instantiate);
332}
333
334static int proc_readfdinfo(struct file *file, struct dir_context *ctx)
335{
336 return proc_readfd_common(file, ctx,
337 proc_fdinfo_instantiate);
338}
339
340const struct inode_operations proc_fdinfo_inode_operations = {
341 .lookup = proc_lookupfdinfo,
342 .setattr = proc_setattr,
343};
344
345const struct file_operations proc_fdinfo_operations = {
346 .read = generic_read_dir,
347 .iterate = proc_readfdinfo,
348 .llseek = default_llseek,
349};
350
