blob: 0788d093f5d86ace99ad80f68f4d7bd924eff294 [file] [log] [blame]
Cyrill Gorcunovfaf60af2012-08-23 14:43:24 +04001#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>
Cyrill Gorcunovddd3e072012-08-26 18:28:20 +04009#include <linux/file.h>
10#include <linux/seq_file.h>
Cyrill Gorcunovfaf60af2012-08-23 14:43:24 +040011
12#include <linux/proc_fs.h>
13
Andrey Vagin49d063c2014-04-07 15:38:34 -070014#include "../mount.h"
Cyrill Gorcunovfaf60af2012-08-23 14:43:24 +040015#include "internal.h"
16#include "fd.h"
17
Cyrill Gorcunovddd3e072012-08-26 18:28:20 +040018static int seq_show(struct seq_file *m, void *v)
Cyrill Gorcunovfaf60af2012-08-23 14:43:24 +040019{
Cyrill Gorcunovfaf60af2012-08-23 14:43:24 +040020 struct files_struct *files = NULL;
Cyrill Gorcunovddd3e072012-08-26 18:28:20 +040021 int f_flags = 0, ret = -ENOENT;
22 struct file *file = NULL;
23 struct task_struct *task;
Cyrill Gorcunovfaf60af2012-08-23 14:43:24 +040024
Cyrill Gorcunovddd3e072012-08-26 18:28:20 +040025 task = get_proc_task(m->private);
26 if (!task)
27 return -ENOENT;
28
29 files = get_files_struct(task);
30 put_task_struct(task);
31
Cyrill Gorcunovfaf60af2012-08-23 14:43:24 +040032 if (files) {
Cyrill Gorcunovddd3e072012-08-26 18:28:20 +040033 int fd = proc_fd(m->private);
34
Cyrill Gorcunovfaf60af2012-08-23 14:43:24 +040035 spin_lock(&files->file_lock);
36 file = fcheck_files(files, fd);
37 if (file) {
Cyrill Gorcunovddd3e072012-08-26 18:28:20 +040038 struct fdtable *fdt = files_fdtable(files);
Cyrill Gorcunovfaf60af2012-08-23 14:43:24 +040039
Al Viroc6f3d812012-08-26 11:01:04 -040040 f_flags = file->f_flags;
Cyrill Gorcunovfaf60af2012-08-23 14:43:24 +040041 if (close_on_exec(fd, fdt))
42 f_flags |= O_CLOEXEC;
43
Cyrill Gorcunovddd3e072012-08-26 18:28:20 +040044 get_file(file);
45 ret = 0;
Cyrill Gorcunovfaf60af2012-08-23 14:43:24 +040046 }
47 spin_unlock(&files->file_lock);
48 put_files_struct(files);
49 }
Cyrill Gorcunovddd3e072012-08-26 18:28:20 +040050
51 if (!ret) {
Andrey Vagin49d063c2014-04-07 15:38:34 -070052 seq_printf(m, "pos:\t%lli\nflags:\t0%o\nmnt_id:\t%i\n",
53 (long long)file->f_pos, f_flags,
54 real_mount(file->f_path.mnt)->mnt_id);
Cyrill Gorcunov55985dd2012-12-17 16:04:55 -080055 if (file->f_op->show_fdinfo)
56 ret = file->f_op->show_fdinfo(m, file);
Cyrill Gorcunovddd3e072012-08-26 18:28:20 +040057 fput(file);
58 }
59
60 return ret;
Cyrill Gorcunovfaf60af2012-08-23 14:43:24 +040061}
62
Cyrill Gorcunovddd3e072012-08-26 18:28:20 +040063static int seq_fdinfo_open(struct inode *inode, struct file *file)
64{
65 return single_open(file, seq_show, inode);
66}
67
68static const struct file_operations proc_fdinfo_file_operations = {
69 .open = seq_fdinfo_open,
70 .read = seq_read,
71 .llseek = seq_lseek,
72 .release = single_release,
73};
74
Cyrill Gorcunovfaf60af2012-08-23 14:43:24 +040075static int tid_fd_revalidate(struct dentry *dentry, unsigned int flags)
76{
77 struct files_struct *files;
78 struct task_struct *task;
79 const struct cred *cred;
80 struct inode *inode;
81 int fd;
82
83 if (flags & LOOKUP_RCU)
84 return -ECHILD;
85
86 inode = dentry->d_inode;
87 task = get_proc_task(inode);
88 fd = proc_fd(inode);
89
90 if (task) {
91 files = get_files_struct(task);
92 if (files) {
93 struct file *file;
94
95 rcu_read_lock();
96 file = fcheck_files(files, fd);
97 if (file) {
98 unsigned f_mode = file->f_mode;
99
100 rcu_read_unlock();
101 put_files_struct(files);
102
103 if (task_dumpable(task)) {
104 rcu_read_lock();
105 cred = __task_cred(task);
106 inode->i_uid = cred->euid;
107 inode->i_gid = cred->egid;
108 rcu_read_unlock();
109 } else {
110 inode->i_uid = GLOBAL_ROOT_UID;
111 inode->i_gid = GLOBAL_ROOT_GID;
112 }
113
114 if (S_ISLNK(inode->i_mode)) {
115 unsigned i_mode = S_IFLNK;
116 if (f_mode & FMODE_READ)
117 i_mode |= S_IRUSR | S_IXUSR;
118 if (f_mode & FMODE_WRITE)
119 i_mode |= S_IWUSR | S_IXUSR;
120 inode->i_mode = i_mode;
121 }
122
123 security_task_to_inode(task, inode);
124 put_task_struct(task);
125 return 1;
126 }
127 rcu_read_unlock();
128 put_files_struct(files);
129 }
130 put_task_struct(task);
131 }
132
133 d_drop(dentry);
134 return 0;
135}
136
137static const struct dentry_operations tid_fd_dentry_operations = {
138 .d_revalidate = tid_fd_revalidate,
139 .d_delete = pid_delete_dentry,
140};
141
142static int proc_fd_link(struct dentry *dentry, struct path *path)
143{
Cyrill Gorcunovddd3e072012-08-26 18:28:20 +0400144 struct files_struct *files = NULL;
145 struct task_struct *task;
146 int ret = -ENOENT;
147
148 task = get_proc_task(dentry->d_inode);
149 if (task) {
150 files = get_files_struct(task);
151 put_task_struct(task);
152 }
153
154 if (files) {
155 int fd = proc_fd(dentry->d_inode);
156 struct file *fd_file;
157
158 spin_lock(&files->file_lock);
159 fd_file = fcheck_files(files, fd);
160 if (fd_file) {
161 *path = fd_file->f_path;
162 path_get(&fd_file->f_path);
163 ret = 0;
164 }
165 spin_unlock(&files->file_lock);
166 put_files_struct(files);
167 }
168
169 return ret;
Cyrill Gorcunovfaf60af2012-08-23 14:43:24 +0400170}
171
Al Viroc52a47a2013-06-15 11:15:20 +0400172static int
Cyrill Gorcunovfaf60af2012-08-23 14:43:24 +0400173proc_fd_instantiate(struct inode *dir, struct dentry *dentry,
174 struct task_struct *task, const void *ptr)
175{
Cyrill Gorcunovfaf60af2012-08-23 14:43:24 +0400176 unsigned fd = (unsigned long)ptr;
177 struct proc_inode *ei;
178 struct inode *inode;
179
180 inode = proc_pid_make_inode(dir->i_sb, task);
181 if (!inode)
182 goto out;
183
184 ei = PROC_I(inode);
185 ei->fd = fd;
186
187 inode->i_mode = S_IFLNK;
188 inode->i_op = &proc_pid_link_inode_operations;
189 inode->i_size = 64;
190
191 ei->op.proc_get_link = proc_fd_link;
192
193 d_set_d_op(dentry, &tid_fd_dentry_operations);
194 d_add(dentry, inode);
195
196 /* Close the race of the process dying before we return the dentry */
197 if (tid_fd_revalidate(dentry, 0))
Al Viroc52a47a2013-06-15 11:15:20 +0400198 return 0;
Cyrill Gorcunovfaf60af2012-08-23 14:43:24 +0400199 out:
Al Viroc52a47a2013-06-15 11:15:20 +0400200 return -ENOENT;
Cyrill Gorcunovfaf60af2012-08-23 14:43:24 +0400201}
202
203static struct dentry *proc_lookupfd_common(struct inode *dir,
204 struct dentry *dentry,
205 instantiate_t instantiate)
206{
207 struct task_struct *task = get_proc_task(dir);
Al Viroc52a47a2013-06-15 11:15:20 +0400208 int result = -ENOENT;
Cyrill Gorcunovfaf60af2012-08-23 14:43:24 +0400209 unsigned fd = name_to_int(dentry);
210
211 if (!task)
212 goto out_no_task;
213 if (fd == ~0U)
214 goto out;
215
216 result = instantiate(dir, dentry, task, (void *)(unsigned long)fd);
217out:
218 put_task_struct(task);
219out_no_task:
Al Viroc52a47a2013-06-15 11:15:20 +0400220 return ERR_PTR(result);
Cyrill Gorcunovfaf60af2012-08-23 14:43:24 +0400221}
222
Al Virof0c3b502013-05-16 12:07:31 -0400223static int proc_readfd_common(struct file *file, struct dir_context *ctx,
224 instantiate_t instantiate)
Cyrill Gorcunovfaf60af2012-08-23 14:43:24 +0400225{
Al Virof0c3b502013-05-16 12:07:31 -0400226 struct task_struct *p = get_proc_task(file_inode(file));
Cyrill Gorcunovfaf60af2012-08-23 14:43:24 +0400227 struct files_struct *files;
Al Virof0c3b502013-05-16 12:07:31 -0400228 unsigned int fd;
Cyrill Gorcunovfaf60af2012-08-23 14:43:24 +0400229
Cyrill Gorcunovfaf60af2012-08-23 14:43:24 +0400230 if (!p)
Al Virof0c3b502013-05-16 12:07:31 -0400231 return -ENOENT;
Cyrill Gorcunovfaf60af2012-08-23 14:43:24 +0400232
Al Virof0c3b502013-05-16 12:07:31 -0400233 if (!dir_emit_dots(file, ctx))
234 goto out;
Al Virof0c3b502013-05-16 12:07:31 -0400235 files = get_files_struct(p);
236 if (!files)
237 goto out;
Cyrill Gorcunovfaf60af2012-08-23 14:43:24 +0400238
Al Virof0c3b502013-05-16 12:07:31 -0400239 rcu_read_lock();
240 for (fd = ctx->pos - 2;
241 fd < files_fdtable(files)->max_fds;
242 fd++, ctx->pos++) {
243 char name[PROC_NUMBUF];
244 int len;
Cyrill Gorcunovfaf60af2012-08-23 14:43:24 +0400245
Al Virof0c3b502013-05-16 12:07:31 -0400246 if (!fcheck_files(files, fd))
247 continue;
248 rcu_read_unlock();
249
250 len = snprintf(name, sizeof(name), "%d", fd);
251 if (!proc_fill_cache(file, ctx,
252 name, len, instantiate, p,
253 (void *)(unsigned long)fd))
254 goto out_fd_loop;
255 rcu_read_lock();
Cyrill Gorcunovfaf60af2012-08-23 14:43:24 +0400256 }
Al Virof0c3b502013-05-16 12:07:31 -0400257 rcu_read_unlock();
258out_fd_loop:
259 put_files_struct(files);
Cyrill Gorcunovfaf60af2012-08-23 14:43:24 +0400260out:
261 put_task_struct(p);
Al Virof0c3b502013-05-16 12:07:31 -0400262 return 0;
Cyrill Gorcunovfaf60af2012-08-23 14:43:24 +0400263}
264
Al Virof0c3b502013-05-16 12:07:31 -0400265static int proc_readfd(struct file *file, struct dir_context *ctx)
Cyrill Gorcunovfaf60af2012-08-23 14:43:24 +0400266{
Al Virof0c3b502013-05-16 12:07:31 -0400267 return proc_readfd_common(file, ctx, proc_fd_instantiate);
Cyrill Gorcunovfaf60af2012-08-23 14:43:24 +0400268}
269
270const struct file_operations proc_fd_operations = {
271 .read = generic_read_dir,
Al Virof0c3b502013-05-16 12:07:31 -0400272 .iterate = proc_readfd,
Cyrill Gorcunovfaf60af2012-08-23 14:43:24 +0400273 .llseek = default_llseek,
274};
275
276static struct dentry *proc_lookupfd(struct inode *dir, struct dentry *dentry,
277 unsigned int flags)
278{
279 return proc_lookupfd_common(dir, dentry, proc_fd_instantiate);
280}
281
282/*
283 * /proc/pid/fd needs a special permission handler so that a process can still
284 * access /proc/self/fd after it has executed a setuid().
285 */
286int proc_fd_permission(struct inode *inode, int mask)
287{
288 int rv = generic_permission(inode, mask);
289 if (rv == 0)
290 return 0;
Oleg Nesterov96d0df72013-09-11 14:24:37 -0700291 if (task_tgid(current) == proc_pid(inode))
Cyrill Gorcunovfaf60af2012-08-23 14:43:24 +0400292 rv = 0;
293 return rv;
294}
295
296const struct inode_operations proc_fd_inode_operations = {
297 .lookup = proc_lookupfd,
298 .permission = proc_fd_permission,
299 .setattr = proc_setattr,
300};
301
Al Viroc52a47a2013-06-15 11:15:20 +0400302static int
Cyrill Gorcunovfaf60af2012-08-23 14:43:24 +0400303proc_fdinfo_instantiate(struct inode *dir, struct dentry *dentry,
304 struct task_struct *task, const void *ptr)
305{
Cyrill Gorcunovfaf60af2012-08-23 14:43:24 +0400306 unsigned fd = (unsigned long)ptr;
307 struct proc_inode *ei;
308 struct inode *inode;
309
310 inode = proc_pid_make_inode(dir->i_sb, task);
311 if (!inode)
312 goto out;
313
314 ei = PROC_I(inode);
315 ei->fd = fd;
316
317 inode->i_mode = S_IFREG | S_IRUSR;
318 inode->i_fop = &proc_fdinfo_file_operations;
319
320 d_set_d_op(dentry, &tid_fd_dentry_operations);
321 d_add(dentry, inode);
322
323 /* Close the race of the process dying before we return the dentry */
324 if (tid_fd_revalidate(dentry, 0))
Al Viroc52a47a2013-06-15 11:15:20 +0400325 return 0;
Cyrill Gorcunovfaf60af2012-08-23 14:43:24 +0400326 out:
Al Viroc52a47a2013-06-15 11:15:20 +0400327 return -ENOENT;
Cyrill Gorcunovfaf60af2012-08-23 14:43:24 +0400328}
329
330static struct dentry *
331proc_lookupfdinfo(struct inode *dir, struct dentry *dentry, unsigned int flags)
332{
333 return proc_lookupfd_common(dir, dentry, proc_fdinfo_instantiate);
334}
335
Al Virof0c3b502013-05-16 12:07:31 -0400336static int proc_readfdinfo(struct file *file, struct dir_context *ctx)
Cyrill Gorcunovfaf60af2012-08-23 14:43:24 +0400337{
Al Virof0c3b502013-05-16 12:07:31 -0400338 return proc_readfd_common(file, ctx,
Cyrill Gorcunovfaf60af2012-08-23 14:43:24 +0400339 proc_fdinfo_instantiate);
340}
341
342const struct inode_operations proc_fdinfo_inode_operations = {
343 .lookup = proc_lookupfdinfo,
344 .setattr = proc_setattr,
345};
346
347const struct file_operations proc_fdinfo_operations = {
348 .read = generic_read_dir,
Al Virof0c3b502013-05-16 12:07:31 -0400349 .iterate = proc_readfdinfo,
Cyrill Gorcunovfaf60af2012-08-23 14:43:24 +0400350 .llseek = default_llseek,
351};