Commit | Line | Data |
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faf60af1 CG |
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> | |
ddd3e077 CG |
9 | #include <linux/file.h> |
10 | #include <linux/seq_file.h> | |
faf60af1 CG |
11 | |
12 | #include <linux/proc_fs.h> | |
13 | ||
14 | #include "internal.h" | |
15 | #include "fd.h" | |
16 | ||
ddd3e077 | 17 | static int seq_show(struct seq_file *m, void *v) |
faf60af1 | 18 | { |
faf60af1 | 19 | struct files_struct *files = NULL; |
ddd3e077 CG |
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); | |
faf60af1 | 30 | |
faf60af1 | 31 | if (files) { |
ddd3e077 CG |
32 | int fd = proc_fd(m->private); |
33 | ||
faf60af1 CG |
34 | spin_lock(&files->file_lock); |
35 | file = fcheck_files(files, fd); | |
36 | if (file) { | |
ddd3e077 | 37 | struct fdtable *fdt = files_fdtable(files); |
faf60af1 | 38 | |
c6f3d811 | 39 | f_flags = file->f_flags; |
faf60af1 CG |
40 | if (close_on_exec(fd, fdt)) |
41 | f_flags |= O_CLOEXEC; | |
42 | ||
ddd3e077 CG |
43 | get_file(file); |
44 | ret = 0; | |
faf60af1 CG |
45 | } |
46 | spin_unlock(&files->file_lock); | |
47 | put_files_struct(files); | |
48 | } | |
ddd3e077 CG |
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; | |
faf60af1 CG |
57 | } |
58 | ||
ddd3e077 CG |
59 | static int seq_fdinfo_open(struct inode *inode, struct file *file) |
60 | { | |
61 | return single_open(file, seq_show, inode); | |
62 | } | |
63 | ||
64 | static 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 | ||
faf60af1 CG |
71 | static 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 | ||
133 | static const struct dentry_operations tid_fd_dentry_operations = { | |
134 | .d_revalidate = tid_fd_revalidate, | |
135 | .d_delete = pid_delete_dentry, | |
136 | }; | |
137 | ||
138 | static int proc_fd_link(struct dentry *dentry, struct path *path) | |
139 | { | |
ddd3e077 CG |
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; | |
faf60af1 CG |
166 | } |
167 | ||
168 | static struct dentry * | |
169 | proc_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 | ||
200 | static 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); | |
214 | out: | |
215 | put_task_struct(task); | |
216 | out_no_task: | |
217 | return result; | |
218 | } | |
219 | ||
220 | static 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(); | |
271 | out_fd_loop: | |
272 | put_files_struct(files); | |
273 | } | |
274 | out: | |
275 | put_task_struct(p); | |
276 | out_no_task: | |
277 | return retval; | |
278 | } | |
279 | ||
faf60af1 CG |
280 | static 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 | ||
285 | const struct file_operations proc_fd_operations = { | |
286 | .read = generic_read_dir, | |
287 | .readdir = proc_readfd, | |
288 | .llseek = default_llseek, | |
289 | }; | |
290 | ||
291 | static 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 | */ | |
301 | int 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 | ||
311 | const struct inode_operations proc_fd_inode_operations = { | |
312 | .lookup = proc_lookupfd, | |
313 | .permission = proc_fd_permission, | |
314 | .setattr = proc_setattr, | |
315 | }; | |
316 | ||
317 | static struct dentry * | |
318 | proc_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 | ||
346 | static struct dentry * | |
347 | proc_lookupfdinfo(struct inode *dir, struct dentry *dentry, unsigned int flags) | |
348 | { | |
349 | return proc_lookupfd_common(dir, dentry, proc_fdinfo_instantiate); | |
350 | } | |
351 | ||
352 | static 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 | ||
358 | const struct inode_operations proc_fdinfo_inode_operations = { | |
359 | .lookup = proc_lookupfdinfo, | |
360 | .setattr = proc_setattr, | |
361 | }; | |
362 | ||
363 | const struct file_operations proc_fdinfo_operations = { | |
364 | .read = generic_read_dir, | |
365 | .readdir = proc_readfdinfo, | |
366 | .llseek = default_llseek, | |
367 | }; |