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-rw-r--r--fs/proc/fd.c367
1 files changed, 367 insertions, 0 deletions
diff --git a/fs/proc/fd.c b/fs/proc/fd.c
new file mode 100644
index 000000000000..f28a875f8779
--- /dev/null
+++ b/fs/proc/fd.c
@@ -0,0 +1,367 @@
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 fput(file);
54 }
55
56 return ret;
57}
58
59static int seq_fdinfo_open(struct inode *inode, struct file *file)
60{
61 return single_open(file, seq_show, inode);
62}
63
64static const struct file_operations proc_fdinfo_file_operations = {
65 .open = seq_fdinfo_open,
66 .read = seq_read,
67 .llseek = seq_lseek,
68 .release = single_release,
69};
70
71static int tid_fd_revalidate(struct dentry *dentry, unsigned int flags)
72{
73 struct files_struct *files;
74 struct task_struct *task;
75 const struct cred *cred;
76 struct inode *inode;
77 int fd;
78
79 if (flags & LOOKUP_RCU)
80 return -ECHILD;
81
82 inode = dentry->d_inode;
83 task = get_proc_task(inode);
84 fd = proc_fd(inode);
85
86 if (task) {
87 files = get_files_struct(task);
88 if (files) {
89 struct file *file;
90
91 rcu_read_lock();
92 file = fcheck_files(files, fd);
93 if (file) {
94 unsigned f_mode = file->f_mode;
95
96 rcu_read_unlock();
97 put_files_struct(files);
98
99 if (task_dumpable(task)) {
100 rcu_read_lock();
101 cred = __task_cred(task);
102 inode->i_uid = cred->euid;
103 inode->i_gid = cred->egid;
104 rcu_read_unlock();
105 } else {
106 inode->i_uid = GLOBAL_ROOT_UID;
107 inode->i_gid = GLOBAL_ROOT_GID;
108 }
109
110 if (S_ISLNK(inode->i_mode)) {
111 unsigned i_mode = S_IFLNK;
112 if (f_mode & FMODE_READ)
113 i_mode |= S_IRUSR | S_IXUSR;
114 if (f_mode & FMODE_WRITE)
115 i_mode |= S_IWUSR | S_IXUSR;
116 inode->i_mode = i_mode;
117 }
118
119 security_task_to_inode(task, inode);
120 put_task_struct(task);
121 return 1;
122 }
123 rcu_read_unlock();
124 put_files_struct(files);
125 }
126 put_task_struct(task);
127 }
128
129 d_drop(dentry);
130 return 0;
131}
132
133static const struct dentry_operations tid_fd_dentry_operations = {
134 .d_revalidate = tid_fd_revalidate,
135 .d_delete = pid_delete_dentry,
136};
137
138static int proc_fd_link(struct dentry *dentry, struct path *path)
139{
140 struct files_struct *files = NULL;
141 struct task_struct *task;
142 int ret = -ENOENT;
143
144 task = get_proc_task(dentry->d_inode);
145 if (task) {
146 files = get_files_struct(task);
147 put_task_struct(task);
148 }
149
150 if (files) {
151 int fd = proc_fd(dentry->d_inode);
152 struct file *fd_file;
153
154 spin_lock(&files->file_lock);
155 fd_file = fcheck_files(files, fd);
156 if (fd_file) {
157 *path = fd_file->f_path;
158 path_get(&fd_file->f_path);
159 ret = 0;
160 }
161 spin_unlock(&files->file_lock);
162 put_files_struct(files);
163 }
164
165 return ret;
166}
167
168static struct dentry *
169proc_fd_instantiate(struct inode *dir, struct dentry *dentry,
170 struct task_struct *task, const void *ptr)
171{
172 struct dentry *error = ERR_PTR(-ENOENT);
173 unsigned fd = (unsigned long)ptr;
174 struct proc_inode *ei;
175 struct inode *inode;
176
177 inode = proc_pid_make_inode(dir->i_sb, task);
178 if (!inode)
179 goto out;
180
181 ei = PROC_I(inode);
182 ei->fd = fd;
183
184 inode->i_mode = S_IFLNK;
185 inode->i_op = &proc_pid_link_inode_operations;
186 inode->i_size = 64;
187
188 ei->op.proc_get_link = proc_fd_link;
189
190 d_set_d_op(dentry, &tid_fd_dentry_operations);
191 d_add(dentry, inode);
192
193 /* Close the race of the process dying before we return the dentry */
194 if (tid_fd_revalidate(dentry, 0))
195 error = NULL;
196 out:
197 return error;
198}
199
200static struct dentry *proc_lookupfd_common(struct inode *dir,
201 struct dentry *dentry,
202 instantiate_t instantiate)
203{
204 struct task_struct *task = get_proc_task(dir);
205 struct dentry *result = ERR_PTR(-ENOENT);
206 unsigned fd = name_to_int(dentry);
207
208 if (!task)
209 goto out_no_task;
210 if (fd == ~0U)
211 goto out;
212
213 result = instantiate(dir, dentry, task, (void *)(unsigned long)fd);
214out:
215 put_task_struct(task);
216out_no_task:
217 return result;
218}
219
220static int proc_readfd_common(struct file * filp, void * dirent,
221 filldir_t filldir, instantiate_t instantiate)
222{
223 struct dentry *dentry = filp->f_path.dentry;
224 struct inode *inode = dentry->d_inode;
225 struct task_struct *p = get_proc_task(inode);
226 struct files_struct *files;
227 unsigned int fd, ino;
228 int retval;
229
230 retval = -ENOENT;
231 if (!p)
232 goto out_no_task;
233 retval = 0;
234
235 fd = filp->f_pos;
236 switch (fd) {
237 case 0:
238 if (filldir(dirent, ".", 1, 0, inode->i_ino, DT_DIR) < 0)
239 goto out;
240 filp->f_pos++;
241 case 1:
242 ino = parent_ino(dentry);
243 if (filldir(dirent, "..", 2, 1, ino, DT_DIR) < 0)
244 goto out;
245 filp->f_pos++;
246 default:
247 files = get_files_struct(p);
248 if (!files)
249 goto out;
250 rcu_read_lock();
251 for (fd = filp->f_pos - 2;
252 fd < files_fdtable(files)->max_fds;
253 fd++, filp->f_pos++) {
254 char name[PROC_NUMBUF];
255 int len;
256 int rv;
257
258 if (!fcheck_files(files, fd))
259 continue;
260 rcu_read_unlock();
261
262 len = snprintf(name, sizeof(name), "%d", fd);
263 rv = proc_fill_cache(filp, dirent, filldir,
264 name, len, instantiate, p,
265 (void *)(unsigned long)fd);
266 if (rv < 0)
267 goto out_fd_loop;
268 rcu_read_lock();
269 }
270 rcu_read_unlock();
271out_fd_loop:
272 put_files_struct(files);
273 }
274out:
275 put_task_struct(p);
276out_no_task:
277 return retval;
278}
279
280static int proc_readfd(struct file *filp, void *dirent, filldir_t filldir)
281{
282 return proc_readfd_common(filp, dirent, filldir, proc_fd_instantiate);
283}
284
285const struct file_operations proc_fd_operations = {
286 .read = generic_read_dir,
287 .readdir = proc_readfd,
288 .llseek = default_llseek,
289};
290
291static struct dentry *proc_lookupfd(struct inode *dir, struct dentry *dentry,
292 unsigned int flags)
293{
294 return proc_lookupfd_common(dir, dentry, proc_fd_instantiate);
295}
296
297/*
298 * /proc/pid/fd needs a special permission handler so that a process can still
299 * access /proc/self/fd after it has executed a setuid().
300 */
301int proc_fd_permission(struct inode *inode, int mask)
302{
303 int rv = generic_permission(inode, mask);
304 if (rv == 0)
305 return 0;
306 if (task_pid(current) == proc_pid(inode))
307 rv = 0;
308 return rv;
309}
310
311const struct inode_operations proc_fd_inode_operations = {
312 .lookup = proc_lookupfd,
313 .permission = proc_fd_permission,
314 .setattr = proc_setattr,
315};
316
317static struct dentry *
318proc_fdinfo_instantiate(struct inode *dir, struct dentry *dentry,
319 struct task_struct *task, const void *ptr)
320{
321 struct dentry *error = ERR_PTR(-ENOENT);
322 unsigned fd = (unsigned long)ptr;
323 struct proc_inode *ei;
324 struct inode *inode;
325
326 inode = proc_pid_make_inode(dir->i_sb, task);
327 if (!inode)
328 goto out;
329
330 ei = PROC_I(inode);
331 ei->fd = fd;
332
333 inode->i_mode = S_IFREG | S_IRUSR;
334 inode->i_fop = &proc_fdinfo_file_operations;
335
336 d_set_d_op(dentry, &tid_fd_dentry_operations);
337 d_add(dentry, inode);
338
339 /* Close the race of the process dying before we return the dentry */
340 if (tid_fd_revalidate(dentry, 0))
341 error = NULL;
342 out:
343 return error;
344}
345
346static struct dentry *
347proc_lookupfdinfo(struct inode *dir, struct dentry *dentry, unsigned int flags)
348{
349 return proc_lookupfd_common(dir, dentry, proc_fdinfo_instantiate);
350}
351
352static int proc_readfdinfo(struct file *filp, void *dirent, filldir_t filldir)
353{
354 return proc_readfd_common(filp, dirent, filldir,
355 proc_fdinfo_instantiate);
356}
357
358const struct inode_operations proc_fdinfo_inode_operations = {
359 .lookup = proc_lookupfdinfo,
360 .setattr = proc_setattr,
361};
362
363const struct file_operations proc_fdinfo_operations = {
364 .read = generic_read_dir,
365 .readdir = proc_readfdinfo,
366 .llseek = default_llseek,
367};
generated by cgit v1.2.2 (git 2.25.0) at 2025-03-01 07:18:03 -0500