xref: /linux/fs/proc/base.c (revision f3d9478b2ce468c3115b02ecae7e975990697f15)
1 /*
2  *  linux/fs/proc/base.c
3  *
4  *  Copyright (C) 1991, 1992 Linus Torvalds
5  *
6  *  proc base directory handling functions
7  *
8  *  1999, Al Viro. Rewritten. Now it covers the whole per-process part.
9  *  Instead of using magical inumbers to determine the kind of object
10  *  we allocate and fill in-core inodes upon lookup. They don't even
11  *  go into icache. We cache the reference to task_struct upon lookup too.
12  *  Eventually it should become a filesystem in its own. We don't use the
13  *  rest of procfs anymore.
14  *
15  *
16  *  Changelog:
17  *  17-Jan-2005
18  *  Allan Bezerra
19  *  Bruna Moreira <bruna.moreira@indt.org.br>
20  *  Edjard Mota <edjard.mota@indt.org.br>
21  *  Ilias Biris <ilias.biris@indt.org.br>
22  *  Mauricio Lin <mauricio.lin@indt.org.br>
23  *
24  *  Embedded Linux Lab - 10LE Instituto Nokia de Tecnologia - INdT
25  *
26  *  A new process specific entry (smaps) included in /proc. It shows the
27  *  size of rss for each memory area. The maps entry lacks information
28  *  about physical memory size (rss) for each mapped file, i.e.,
29  *  rss information for executables and library files.
30  *  This additional information is useful for any tools that need to know
31  *  about physical memory consumption for a process specific library.
32  *
33  *  Changelog:
34  *  21-Feb-2005
35  *  Embedded Linux Lab - 10LE Instituto Nokia de Tecnologia - INdT
36  *  Pud inclusion in the page table walking.
37  *
38  *  ChangeLog:
39  *  10-Mar-2005
40  *  10LE Instituto Nokia de Tecnologia - INdT:
41  *  A better way to walks through the page table as suggested by Hugh Dickins.
42  *
43  *  Simo Piiroinen <simo.piiroinen@nokia.com>:
44  *  Smaps information related to shared, private, clean and dirty pages.
45  *
46  *  Paul Mundt <paul.mundt@nokia.com>:
47  *  Overall revision about smaps.
48  */
49 
50 #include <asm/uaccess.h>
51 
52 #include <linux/config.h>
53 #include <linux/errno.h>
54 #include <linux/time.h>
55 #include <linux/proc_fs.h>
56 #include <linux/stat.h>
57 #include <linux/init.h>
58 #include <linux/capability.h>
59 #include <linux/file.h>
60 #include <linux/string.h>
61 #include <linux/seq_file.h>
62 #include <linux/namei.h>
63 #include <linux/namespace.h>
64 #include <linux/mm.h>
65 #include <linux/smp_lock.h>
66 #include <linux/rcupdate.h>
67 #include <linux/kallsyms.h>
68 #include <linux/mount.h>
69 #include <linux/security.h>
70 #include <linux/ptrace.h>
71 #include <linux/seccomp.h>
72 #include <linux/cpuset.h>
73 #include <linux/audit.h>
74 #include <linux/poll.h>
75 #include "internal.h"
76 
77 /*
78  * For hysterical raisins we keep the same inumbers as in the old procfs.
79  * Feel free to change the macro below - just keep the range distinct from
80  * inumbers of the rest of procfs (currently those are in 0x0000--0xffff).
81  * As soon as we'll get a separate superblock we will be able to forget
82  * about magical ranges too.
83  */
84 
85 #define fake_ino(pid,ino) (((pid)<<16)|(ino))
86 
87 enum pid_directory_inos {
88 	PROC_TGID_INO = 2,
89 	PROC_TGID_TASK,
90 	PROC_TGID_STATUS,
91 	PROC_TGID_MEM,
92 #ifdef CONFIG_SECCOMP
93 	PROC_TGID_SECCOMP,
94 #endif
95 	PROC_TGID_CWD,
96 	PROC_TGID_ROOT,
97 	PROC_TGID_EXE,
98 	PROC_TGID_FD,
99 	PROC_TGID_ENVIRON,
100 	PROC_TGID_AUXV,
101 	PROC_TGID_CMDLINE,
102 	PROC_TGID_STAT,
103 	PROC_TGID_STATM,
104 	PROC_TGID_MAPS,
105 	PROC_TGID_NUMA_MAPS,
106 	PROC_TGID_MOUNTS,
107 	PROC_TGID_MOUNTSTATS,
108 	PROC_TGID_WCHAN,
109 #ifdef CONFIG_MMU
110 	PROC_TGID_SMAPS,
111 #endif
112 #ifdef CONFIG_SCHEDSTATS
113 	PROC_TGID_SCHEDSTAT,
114 #endif
115 #ifdef CONFIG_CPUSETS
116 	PROC_TGID_CPUSET,
117 #endif
118 #ifdef CONFIG_SECURITY
119 	PROC_TGID_ATTR,
120 	PROC_TGID_ATTR_CURRENT,
121 	PROC_TGID_ATTR_PREV,
122 	PROC_TGID_ATTR_EXEC,
123 	PROC_TGID_ATTR_FSCREATE,
124 #endif
125 #ifdef CONFIG_AUDITSYSCALL
126 	PROC_TGID_LOGINUID,
127 #endif
128 	PROC_TGID_OOM_SCORE,
129 	PROC_TGID_OOM_ADJUST,
130 	PROC_TID_INO,
131 	PROC_TID_STATUS,
132 	PROC_TID_MEM,
133 #ifdef CONFIG_SECCOMP
134 	PROC_TID_SECCOMP,
135 #endif
136 	PROC_TID_CWD,
137 	PROC_TID_ROOT,
138 	PROC_TID_EXE,
139 	PROC_TID_FD,
140 	PROC_TID_ENVIRON,
141 	PROC_TID_AUXV,
142 	PROC_TID_CMDLINE,
143 	PROC_TID_STAT,
144 	PROC_TID_STATM,
145 	PROC_TID_MAPS,
146 	PROC_TID_NUMA_MAPS,
147 	PROC_TID_MOUNTS,
148 	PROC_TID_MOUNTSTATS,
149 	PROC_TID_WCHAN,
150 #ifdef CONFIG_MMU
151 	PROC_TID_SMAPS,
152 #endif
153 #ifdef CONFIG_SCHEDSTATS
154 	PROC_TID_SCHEDSTAT,
155 #endif
156 #ifdef CONFIG_CPUSETS
157 	PROC_TID_CPUSET,
158 #endif
159 #ifdef CONFIG_SECURITY
160 	PROC_TID_ATTR,
161 	PROC_TID_ATTR_CURRENT,
162 	PROC_TID_ATTR_PREV,
163 	PROC_TID_ATTR_EXEC,
164 	PROC_TID_ATTR_FSCREATE,
165 #endif
166 #ifdef CONFIG_AUDITSYSCALL
167 	PROC_TID_LOGINUID,
168 #endif
169 	PROC_TID_OOM_SCORE,
170 	PROC_TID_OOM_ADJUST,
171 
172 	/* Add new entries before this */
173 	PROC_TID_FD_DIR = 0x8000,	/* 0x8000-0xffff */
174 };
175 
176 struct pid_entry {
177 	int type;
178 	int len;
179 	char *name;
180 	mode_t mode;
181 };
182 
183 #define E(type,name,mode) {(type),sizeof(name)-1,(name),(mode)}
184 
185 static struct pid_entry tgid_base_stuff[] = {
186 	E(PROC_TGID_TASK,      "task",    S_IFDIR|S_IRUGO|S_IXUGO),
187 	E(PROC_TGID_FD,        "fd",      S_IFDIR|S_IRUSR|S_IXUSR),
188 	E(PROC_TGID_ENVIRON,   "environ", S_IFREG|S_IRUSR),
189 	E(PROC_TGID_AUXV,      "auxv",	  S_IFREG|S_IRUSR),
190 	E(PROC_TGID_STATUS,    "status",  S_IFREG|S_IRUGO),
191 	E(PROC_TGID_CMDLINE,   "cmdline", S_IFREG|S_IRUGO),
192 	E(PROC_TGID_STAT,      "stat",    S_IFREG|S_IRUGO),
193 	E(PROC_TGID_STATM,     "statm",   S_IFREG|S_IRUGO),
194 	E(PROC_TGID_MAPS,      "maps",    S_IFREG|S_IRUGO),
195 #ifdef CONFIG_NUMA
196 	E(PROC_TGID_NUMA_MAPS, "numa_maps", S_IFREG|S_IRUGO),
197 #endif
198 	E(PROC_TGID_MEM,       "mem",     S_IFREG|S_IRUSR|S_IWUSR),
199 #ifdef CONFIG_SECCOMP
200 	E(PROC_TGID_SECCOMP,   "seccomp", S_IFREG|S_IRUSR|S_IWUSR),
201 #endif
202 	E(PROC_TGID_CWD,       "cwd",     S_IFLNK|S_IRWXUGO),
203 	E(PROC_TGID_ROOT,      "root",    S_IFLNK|S_IRWXUGO),
204 	E(PROC_TGID_EXE,       "exe",     S_IFLNK|S_IRWXUGO),
205 	E(PROC_TGID_MOUNTS,    "mounts",  S_IFREG|S_IRUGO),
206 	E(PROC_TGID_MOUNTSTATS, "mountstats", S_IFREG|S_IRUSR),
207 #ifdef CONFIG_MMU
208 	E(PROC_TGID_SMAPS,     "smaps",   S_IFREG|S_IRUGO),
209 #endif
210 #ifdef CONFIG_SECURITY
211 	E(PROC_TGID_ATTR,      "attr",    S_IFDIR|S_IRUGO|S_IXUGO),
212 #endif
213 #ifdef CONFIG_KALLSYMS
214 	E(PROC_TGID_WCHAN,     "wchan",   S_IFREG|S_IRUGO),
215 #endif
216 #ifdef CONFIG_SCHEDSTATS
217 	E(PROC_TGID_SCHEDSTAT, "schedstat", S_IFREG|S_IRUGO),
218 #endif
219 #ifdef CONFIG_CPUSETS
220 	E(PROC_TGID_CPUSET,    "cpuset",  S_IFREG|S_IRUGO),
221 #endif
222 	E(PROC_TGID_OOM_SCORE, "oom_score",S_IFREG|S_IRUGO),
223 	E(PROC_TGID_OOM_ADJUST,"oom_adj", S_IFREG|S_IRUGO|S_IWUSR),
224 #ifdef CONFIG_AUDITSYSCALL
225 	E(PROC_TGID_LOGINUID, "loginuid", S_IFREG|S_IWUSR|S_IRUGO),
226 #endif
227 	{0,0,NULL,0}
228 };
229 static struct pid_entry tid_base_stuff[] = {
230 	E(PROC_TID_FD,         "fd",      S_IFDIR|S_IRUSR|S_IXUSR),
231 	E(PROC_TID_ENVIRON,    "environ", S_IFREG|S_IRUSR),
232 	E(PROC_TID_AUXV,       "auxv",	  S_IFREG|S_IRUSR),
233 	E(PROC_TID_STATUS,     "status",  S_IFREG|S_IRUGO),
234 	E(PROC_TID_CMDLINE,    "cmdline", S_IFREG|S_IRUGO),
235 	E(PROC_TID_STAT,       "stat",    S_IFREG|S_IRUGO),
236 	E(PROC_TID_STATM,      "statm",   S_IFREG|S_IRUGO),
237 	E(PROC_TID_MAPS,       "maps",    S_IFREG|S_IRUGO),
238 #ifdef CONFIG_NUMA
239 	E(PROC_TID_NUMA_MAPS,  "numa_maps",    S_IFREG|S_IRUGO),
240 #endif
241 	E(PROC_TID_MEM,        "mem",     S_IFREG|S_IRUSR|S_IWUSR),
242 #ifdef CONFIG_SECCOMP
243 	E(PROC_TID_SECCOMP,    "seccomp", S_IFREG|S_IRUSR|S_IWUSR),
244 #endif
245 	E(PROC_TID_CWD,        "cwd",     S_IFLNK|S_IRWXUGO),
246 	E(PROC_TID_ROOT,       "root",    S_IFLNK|S_IRWXUGO),
247 	E(PROC_TID_EXE,        "exe",     S_IFLNK|S_IRWXUGO),
248 	E(PROC_TID_MOUNTS,     "mounts",  S_IFREG|S_IRUGO),
249 #ifdef CONFIG_MMU
250 	E(PROC_TID_SMAPS,      "smaps",   S_IFREG|S_IRUGO),
251 #endif
252 #ifdef CONFIG_SECURITY
253 	E(PROC_TID_ATTR,       "attr",    S_IFDIR|S_IRUGO|S_IXUGO),
254 #endif
255 #ifdef CONFIG_KALLSYMS
256 	E(PROC_TID_WCHAN,      "wchan",   S_IFREG|S_IRUGO),
257 #endif
258 #ifdef CONFIG_SCHEDSTATS
259 	E(PROC_TID_SCHEDSTAT, "schedstat",S_IFREG|S_IRUGO),
260 #endif
261 #ifdef CONFIG_CPUSETS
262 	E(PROC_TID_CPUSET,     "cpuset",  S_IFREG|S_IRUGO),
263 #endif
264 	E(PROC_TID_OOM_SCORE,  "oom_score",S_IFREG|S_IRUGO),
265 	E(PROC_TID_OOM_ADJUST, "oom_adj", S_IFREG|S_IRUGO|S_IWUSR),
266 #ifdef CONFIG_AUDITSYSCALL
267 	E(PROC_TID_LOGINUID, "loginuid", S_IFREG|S_IWUSR|S_IRUGO),
268 #endif
269 	{0,0,NULL,0}
270 };
271 
272 #ifdef CONFIG_SECURITY
273 static struct pid_entry tgid_attr_stuff[] = {
274 	E(PROC_TGID_ATTR_CURRENT,  "current",  S_IFREG|S_IRUGO|S_IWUGO),
275 	E(PROC_TGID_ATTR_PREV,     "prev",     S_IFREG|S_IRUGO),
276 	E(PROC_TGID_ATTR_EXEC,     "exec",     S_IFREG|S_IRUGO|S_IWUGO),
277 	E(PROC_TGID_ATTR_FSCREATE, "fscreate", S_IFREG|S_IRUGO|S_IWUGO),
278 	{0,0,NULL,0}
279 };
280 static struct pid_entry tid_attr_stuff[] = {
281 	E(PROC_TID_ATTR_CURRENT,   "current",  S_IFREG|S_IRUGO|S_IWUGO),
282 	E(PROC_TID_ATTR_PREV,      "prev",     S_IFREG|S_IRUGO),
283 	E(PROC_TID_ATTR_EXEC,      "exec",     S_IFREG|S_IRUGO|S_IWUGO),
284 	E(PROC_TID_ATTR_FSCREATE,  "fscreate", S_IFREG|S_IRUGO|S_IWUGO),
285 	{0,0,NULL,0}
286 };
287 #endif
288 
289 #undef E
290 
291 static int proc_fd_link(struct inode *inode, struct dentry **dentry, struct vfsmount **mnt)
292 {
293 	struct task_struct *task = proc_task(inode);
294 	struct files_struct *files;
295 	struct file *file;
296 	int fd = proc_type(inode) - PROC_TID_FD_DIR;
297 
298 	files = get_files_struct(task);
299 	if (files) {
300 		/*
301 		 * We are not taking a ref to the file structure, so we must
302 		 * hold ->file_lock.
303 		 */
304 		spin_lock(&files->file_lock);
305 		file = fcheck_files(files, fd);
306 		if (file) {
307 			*mnt = mntget(file->f_vfsmnt);
308 			*dentry = dget(file->f_dentry);
309 			spin_unlock(&files->file_lock);
310 			put_files_struct(files);
311 			return 0;
312 		}
313 		spin_unlock(&files->file_lock);
314 		put_files_struct(files);
315 	}
316 	return -ENOENT;
317 }
318 
319 static struct fs_struct *get_fs_struct(struct task_struct *task)
320 {
321 	struct fs_struct *fs;
322 	task_lock(task);
323 	fs = task->fs;
324 	if(fs)
325 		atomic_inc(&fs->count);
326 	task_unlock(task);
327 	return fs;
328 }
329 
330 static int proc_cwd_link(struct inode *inode, struct dentry **dentry, struct vfsmount **mnt)
331 {
332 	struct fs_struct *fs = get_fs_struct(proc_task(inode));
333 	int result = -ENOENT;
334 	if (fs) {
335 		read_lock(&fs->lock);
336 		*mnt = mntget(fs->pwdmnt);
337 		*dentry = dget(fs->pwd);
338 		read_unlock(&fs->lock);
339 		result = 0;
340 		put_fs_struct(fs);
341 	}
342 	return result;
343 }
344 
345 static int proc_root_link(struct inode *inode, struct dentry **dentry, struct vfsmount **mnt)
346 {
347 	struct fs_struct *fs = get_fs_struct(proc_task(inode));
348 	int result = -ENOENT;
349 	if (fs) {
350 		read_lock(&fs->lock);
351 		*mnt = mntget(fs->rootmnt);
352 		*dentry = dget(fs->root);
353 		read_unlock(&fs->lock);
354 		result = 0;
355 		put_fs_struct(fs);
356 	}
357 	return result;
358 }
359 
360 
361 /* Same as proc_root_link, but this addionally tries to get fs from other
362  * threads in the group */
363 static int proc_task_root_link(struct inode *inode, struct dentry **dentry,
364 				struct vfsmount **mnt)
365 {
366 	struct fs_struct *fs;
367 	int result = -ENOENT;
368 	struct task_struct *leader = proc_task(inode);
369 
370 	task_lock(leader);
371 	fs = leader->fs;
372 	if (fs) {
373 		atomic_inc(&fs->count);
374 		task_unlock(leader);
375 	} else {
376 		/* Try to get fs from other threads */
377 		task_unlock(leader);
378 		read_lock(&tasklist_lock);
379 		if (pid_alive(leader)) {
380 			struct task_struct *task = leader;
381 
382 			while ((task = next_thread(task)) != leader) {
383 				task_lock(task);
384 				fs = task->fs;
385 				if (fs) {
386 					atomic_inc(&fs->count);
387 					task_unlock(task);
388 					break;
389 				}
390 				task_unlock(task);
391 			}
392 		}
393 		read_unlock(&tasklist_lock);
394 	}
395 
396 	if (fs) {
397 		read_lock(&fs->lock);
398 		*mnt = mntget(fs->rootmnt);
399 		*dentry = dget(fs->root);
400 		read_unlock(&fs->lock);
401 		result = 0;
402 		put_fs_struct(fs);
403 	}
404 	return result;
405 }
406 
407 
408 #define MAY_PTRACE(task) \
409 	(task == current || \
410 	(task->parent == current && \
411 	(task->ptrace & PT_PTRACED) && \
412 	 (task->state == TASK_STOPPED || task->state == TASK_TRACED) && \
413 	 security_ptrace(current,task) == 0))
414 
415 static int proc_pid_environ(struct task_struct *task, char * buffer)
416 {
417 	int res = 0;
418 	struct mm_struct *mm = get_task_mm(task);
419 	if (mm) {
420 		unsigned int len = mm->env_end - mm->env_start;
421 		if (len > PAGE_SIZE)
422 			len = PAGE_SIZE;
423 		res = access_process_vm(task, mm->env_start, buffer, len, 0);
424 		if (!ptrace_may_attach(task))
425 			res = -ESRCH;
426 		mmput(mm);
427 	}
428 	return res;
429 }
430 
431 static int proc_pid_cmdline(struct task_struct *task, char * buffer)
432 {
433 	int res = 0;
434 	unsigned int len;
435 	struct mm_struct *mm = get_task_mm(task);
436 	if (!mm)
437 		goto out;
438 	if (!mm->arg_end)
439 		goto out_mm;	/* Shh! No looking before we're done */
440 
441  	len = mm->arg_end - mm->arg_start;
442 
443 	if (len > PAGE_SIZE)
444 		len = PAGE_SIZE;
445 
446 	res = access_process_vm(task, mm->arg_start, buffer, len, 0);
447 
448 	// If the nul at the end of args has been overwritten, then
449 	// assume application is using setproctitle(3).
450 	if (res > 0 && buffer[res-1] != '\0' && len < PAGE_SIZE) {
451 		len = strnlen(buffer, res);
452 		if (len < res) {
453 		    res = len;
454 		} else {
455 			len = mm->env_end - mm->env_start;
456 			if (len > PAGE_SIZE - res)
457 				len = PAGE_SIZE - res;
458 			res += access_process_vm(task, mm->env_start, buffer+res, len, 0);
459 			res = strnlen(buffer, res);
460 		}
461 	}
462 out_mm:
463 	mmput(mm);
464 out:
465 	return res;
466 }
467 
468 static int proc_pid_auxv(struct task_struct *task, char *buffer)
469 {
470 	int res = 0;
471 	struct mm_struct *mm = get_task_mm(task);
472 	if (mm) {
473 		unsigned int nwords = 0;
474 		do
475 			nwords += 2;
476 		while (mm->saved_auxv[nwords - 2] != 0); /* AT_NULL */
477 		res = nwords * sizeof(mm->saved_auxv[0]);
478 		if (res > PAGE_SIZE)
479 			res = PAGE_SIZE;
480 		memcpy(buffer, mm->saved_auxv, res);
481 		mmput(mm);
482 	}
483 	return res;
484 }
485 
486 
487 #ifdef CONFIG_KALLSYMS
488 /*
489  * Provides a wchan file via kallsyms in a proper one-value-per-file format.
490  * Returns the resolved symbol.  If that fails, simply return the address.
491  */
492 static int proc_pid_wchan(struct task_struct *task, char *buffer)
493 {
494 	char *modname;
495 	const char *sym_name;
496 	unsigned long wchan, size, offset;
497 	char namebuf[KSYM_NAME_LEN+1];
498 
499 	wchan = get_wchan(task);
500 
501 	sym_name = kallsyms_lookup(wchan, &size, &offset, &modname, namebuf);
502 	if (sym_name)
503 		return sprintf(buffer, "%s", sym_name);
504 	return sprintf(buffer, "%lu", wchan);
505 }
506 #endif /* CONFIG_KALLSYMS */
507 
508 #ifdef CONFIG_SCHEDSTATS
509 /*
510  * Provides /proc/PID/schedstat
511  */
512 static int proc_pid_schedstat(struct task_struct *task, char *buffer)
513 {
514 	return sprintf(buffer, "%lu %lu %lu\n",
515 			task->sched_info.cpu_time,
516 			task->sched_info.run_delay,
517 			task->sched_info.pcnt);
518 }
519 #endif
520 
521 /* The badness from the OOM killer */
522 unsigned long badness(struct task_struct *p, unsigned long uptime);
523 static int proc_oom_score(struct task_struct *task, char *buffer)
524 {
525 	unsigned long points;
526 	struct timespec uptime;
527 
528 	do_posix_clock_monotonic_gettime(&uptime);
529 	points = badness(task, uptime.tv_sec);
530 	return sprintf(buffer, "%lu\n", points);
531 }
532 
533 /************************************************************************/
534 /*                       Here the fs part begins                        */
535 /************************************************************************/
536 
537 /* permission checks */
538 
539 /* If the process being read is separated by chroot from the reading process,
540  * don't let the reader access the threads.
541  *
542  * note: this does dput(root) and mntput(vfsmnt) on exit.
543  */
544 static int proc_check_chroot(struct dentry *root, struct vfsmount *vfsmnt)
545 {
546 	struct dentry *de, *base;
547 	struct vfsmount *our_vfsmnt, *mnt;
548 	int res = 0;
549 
550 	read_lock(&current->fs->lock);
551 	our_vfsmnt = mntget(current->fs->rootmnt);
552 	base = dget(current->fs->root);
553 	read_unlock(&current->fs->lock);
554 
555 	spin_lock(&vfsmount_lock);
556 	de = root;
557 	mnt = vfsmnt;
558 
559 	while (mnt != our_vfsmnt) {
560 		if (mnt == mnt->mnt_parent)
561 			goto out;
562 		de = mnt->mnt_mountpoint;
563 		mnt = mnt->mnt_parent;
564 	}
565 
566 	if (!is_subdir(de, base))
567 		goto out;
568 	spin_unlock(&vfsmount_lock);
569 
570 exit:
571 	dput(base);
572 	mntput(our_vfsmnt);
573 	dput(root);
574 	mntput(vfsmnt);
575 	return res;
576 out:
577 	spin_unlock(&vfsmount_lock);
578 	res = -EACCES;
579 	goto exit;
580 }
581 
582 static int proc_check_root(struct inode *inode)
583 {
584 	struct dentry *root;
585 	struct vfsmount *vfsmnt;
586 
587 	if (proc_root_link(inode, &root, &vfsmnt)) /* Ewww... */
588 		return -ENOENT;
589 	return proc_check_chroot(root, vfsmnt);
590 }
591 
592 static int proc_permission(struct inode *inode, int mask, struct nameidata *nd)
593 {
594 	if (generic_permission(inode, mask, NULL) != 0)
595 		return -EACCES;
596 	return proc_check_root(inode);
597 }
598 
599 static int proc_task_permission(struct inode *inode, int mask, struct nameidata *nd)
600 {
601 	struct dentry *root;
602 	struct vfsmount *vfsmnt;
603 
604 	if (generic_permission(inode, mask, NULL) != 0)
605 		return -EACCES;
606 
607 	if (proc_task_root_link(inode, &root, &vfsmnt))
608 		return -ENOENT;
609 
610 	return proc_check_chroot(root, vfsmnt);
611 }
612 
613 extern struct seq_operations proc_pid_maps_op;
614 static int maps_open(struct inode *inode, struct file *file)
615 {
616 	struct task_struct *task = proc_task(inode);
617 	int ret = seq_open(file, &proc_pid_maps_op);
618 	if (!ret) {
619 		struct seq_file *m = file->private_data;
620 		m->private = task;
621 	}
622 	return ret;
623 }
624 
625 static struct file_operations proc_maps_operations = {
626 	.open		= maps_open,
627 	.read		= seq_read,
628 	.llseek		= seq_lseek,
629 	.release	= seq_release,
630 };
631 
632 #ifdef CONFIG_NUMA
633 extern struct seq_operations proc_pid_numa_maps_op;
634 static int numa_maps_open(struct inode *inode, struct file *file)
635 {
636 	struct task_struct *task = proc_task(inode);
637 	int ret = seq_open(file, &proc_pid_numa_maps_op);
638 	if (!ret) {
639 		struct seq_file *m = file->private_data;
640 		m->private = task;
641 	}
642 	return ret;
643 }
644 
645 static struct file_operations proc_numa_maps_operations = {
646 	.open		= numa_maps_open,
647 	.read		= seq_read,
648 	.llseek		= seq_lseek,
649 	.release	= seq_release,
650 };
651 #endif
652 
653 #ifdef CONFIG_MMU
654 extern struct seq_operations proc_pid_smaps_op;
655 static int smaps_open(struct inode *inode, struct file *file)
656 {
657 	struct task_struct *task = proc_task(inode);
658 	int ret = seq_open(file, &proc_pid_smaps_op);
659 	if (!ret) {
660 		struct seq_file *m = file->private_data;
661 		m->private = task;
662 	}
663 	return ret;
664 }
665 
666 static struct file_operations proc_smaps_operations = {
667 	.open		= smaps_open,
668 	.read		= seq_read,
669 	.llseek		= seq_lseek,
670 	.release	= seq_release,
671 };
672 #endif
673 
674 extern struct seq_operations mounts_op;
675 struct proc_mounts {
676 	struct seq_file m;
677 	int event;
678 };
679 
680 static int mounts_open(struct inode *inode, struct file *file)
681 {
682 	struct task_struct *task = proc_task(inode);
683 	struct namespace *namespace;
684 	struct proc_mounts *p;
685 	int ret = -EINVAL;
686 
687 	task_lock(task);
688 	namespace = task->namespace;
689 	if (namespace)
690 		get_namespace(namespace);
691 	task_unlock(task);
692 
693 	if (namespace) {
694 		ret = -ENOMEM;
695 		p = kmalloc(sizeof(struct proc_mounts), GFP_KERNEL);
696 		if (p) {
697 			file->private_data = &p->m;
698 			ret = seq_open(file, &mounts_op);
699 			if (!ret) {
700 				p->m.private = namespace;
701 				p->event = namespace->event;
702 				return 0;
703 			}
704 			kfree(p);
705 		}
706 		put_namespace(namespace);
707 	}
708 	return ret;
709 }
710 
711 static int mounts_release(struct inode *inode, struct file *file)
712 {
713 	struct seq_file *m = file->private_data;
714 	struct namespace *namespace = m->private;
715 	put_namespace(namespace);
716 	return seq_release(inode, file);
717 }
718 
719 static unsigned mounts_poll(struct file *file, poll_table *wait)
720 {
721 	struct proc_mounts *p = file->private_data;
722 	struct namespace *ns = p->m.private;
723 	unsigned res = 0;
724 
725 	poll_wait(file, &ns->poll, wait);
726 
727 	spin_lock(&vfsmount_lock);
728 	if (p->event != ns->event) {
729 		p->event = ns->event;
730 		res = POLLERR;
731 	}
732 	spin_unlock(&vfsmount_lock);
733 
734 	return res;
735 }
736 
737 static struct file_operations proc_mounts_operations = {
738 	.open		= mounts_open,
739 	.read		= seq_read,
740 	.llseek		= seq_lseek,
741 	.release	= mounts_release,
742 	.poll		= mounts_poll,
743 };
744 
745 extern struct seq_operations mountstats_op;
746 static int mountstats_open(struct inode *inode, struct file *file)
747 {
748 	struct task_struct *task = proc_task(inode);
749 	int ret = seq_open(file, &mountstats_op);
750 
751 	if (!ret) {
752 		struct seq_file *m = file->private_data;
753 		struct namespace *namespace;
754 		task_lock(task);
755 		namespace = task->namespace;
756 		if (namespace)
757 			get_namespace(namespace);
758 		task_unlock(task);
759 
760 		if (namespace)
761 			m->private = namespace;
762 		else {
763 			seq_release(inode, file);
764 			ret = -EINVAL;
765 		}
766 	}
767 	return ret;
768 }
769 
770 static struct file_operations proc_mountstats_operations = {
771 	.open		= mountstats_open,
772 	.read		= seq_read,
773 	.llseek		= seq_lseek,
774 	.release	= mounts_release,
775 };
776 
777 #define PROC_BLOCK_SIZE	(3*1024)		/* 4K page size but our output routines use some slack for overruns */
778 
779 static ssize_t proc_info_read(struct file * file, char __user * buf,
780 			  size_t count, loff_t *ppos)
781 {
782 	struct inode * inode = file->f_dentry->d_inode;
783 	unsigned long page;
784 	ssize_t length;
785 	struct task_struct *task = proc_task(inode);
786 
787 	if (count > PROC_BLOCK_SIZE)
788 		count = PROC_BLOCK_SIZE;
789 	if (!(page = __get_free_page(GFP_KERNEL)))
790 		return -ENOMEM;
791 
792 	length = PROC_I(inode)->op.proc_read(task, (char*)page);
793 
794 	if (length >= 0)
795 		length = simple_read_from_buffer(buf, count, ppos, (char *)page, length);
796 	free_page(page);
797 	return length;
798 }
799 
800 static struct file_operations proc_info_file_operations = {
801 	.read		= proc_info_read,
802 };
803 
804 static int mem_open(struct inode* inode, struct file* file)
805 {
806 	file->private_data = (void*)((long)current->self_exec_id);
807 	return 0;
808 }
809 
810 static ssize_t mem_read(struct file * file, char __user * buf,
811 			size_t count, loff_t *ppos)
812 {
813 	struct task_struct *task = proc_task(file->f_dentry->d_inode);
814 	char *page;
815 	unsigned long src = *ppos;
816 	int ret = -ESRCH;
817 	struct mm_struct *mm;
818 
819 	if (!MAY_PTRACE(task) || !ptrace_may_attach(task))
820 		goto out;
821 
822 	ret = -ENOMEM;
823 	page = (char *)__get_free_page(GFP_USER);
824 	if (!page)
825 		goto out;
826 
827 	ret = 0;
828 
829 	mm = get_task_mm(task);
830 	if (!mm)
831 		goto out_free;
832 
833 	ret = -EIO;
834 
835 	if (file->private_data != (void*)((long)current->self_exec_id))
836 		goto out_put;
837 
838 	ret = 0;
839 
840 	while (count > 0) {
841 		int this_len, retval;
842 
843 		this_len = (count > PAGE_SIZE) ? PAGE_SIZE : count;
844 		retval = access_process_vm(task, src, page, this_len, 0);
845 		if (!retval || !MAY_PTRACE(task) || !ptrace_may_attach(task)) {
846 			if (!ret)
847 				ret = -EIO;
848 			break;
849 		}
850 
851 		if (copy_to_user(buf, page, retval)) {
852 			ret = -EFAULT;
853 			break;
854 		}
855 
856 		ret += retval;
857 		src += retval;
858 		buf += retval;
859 		count -= retval;
860 	}
861 	*ppos = src;
862 
863 out_put:
864 	mmput(mm);
865 out_free:
866 	free_page((unsigned long) page);
867 out:
868 	return ret;
869 }
870 
871 #define mem_write NULL
872 
873 #ifndef mem_write
874 /* This is a security hazard */
875 static ssize_t mem_write(struct file * file, const char * buf,
876 			 size_t count, loff_t *ppos)
877 {
878 	int copied = 0;
879 	char *page;
880 	struct task_struct *task = proc_task(file->f_dentry->d_inode);
881 	unsigned long dst = *ppos;
882 
883 	if (!MAY_PTRACE(task) || !ptrace_may_attach(task))
884 		return -ESRCH;
885 
886 	page = (char *)__get_free_page(GFP_USER);
887 	if (!page)
888 		return -ENOMEM;
889 
890 	while (count > 0) {
891 		int this_len, retval;
892 
893 		this_len = (count > PAGE_SIZE) ? PAGE_SIZE : count;
894 		if (copy_from_user(page, buf, this_len)) {
895 			copied = -EFAULT;
896 			break;
897 		}
898 		retval = access_process_vm(task, dst, page, this_len, 1);
899 		if (!retval) {
900 			if (!copied)
901 				copied = -EIO;
902 			break;
903 		}
904 		copied += retval;
905 		buf += retval;
906 		dst += retval;
907 		count -= retval;
908 	}
909 	*ppos = dst;
910 	free_page((unsigned long) page);
911 	return copied;
912 }
913 #endif
914 
915 static loff_t mem_lseek(struct file * file, loff_t offset, int orig)
916 {
917 	switch (orig) {
918 	case 0:
919 		file->f_pos = offset;
920 		break;
921 	case 1:
922 		file->f_pos += offset;
923 		break;
924 	default:
925 		return -EINVAL;
926 	}
927 	force_successful_syscall_return();
928 	return file->f_pos;
929 }
930 
931 static struct file_operations proc_mem_operations = {
932 	.llseek		= mem_lseek,
933 	.read		= mem_read,
934 	.write		= mem_write,
935 	.open		= mem_open,
936 };
937 
938 static ssize_t oom_adjust_read(struct file *file, char __user *buf,
939 				size_t count, loff_t *ppos)
940 {
941 	struct task_struct *task = proc_task(file->f_dentry->d_inode);
942 	char buffer[8];
943 	size_t len;
944 	int oom_adjust = task->oomkilladj;
945 	loff_t __ppos = *ppos;
946 
947 	len = sprintf(buffer, "%i\n", oom_adjust);
948 	if (__ppos >= len)
949 		return 0;
950 	if (count > len-__ppos)
951 		count = len-__ppos;
952 	if (copy_to_user(buf, buffer + __ppos, count))
953 		return -EFAULT;
954 	*ppos = __ppos + count;
955 	return count;
956 }
957 
958 static ssize_t oom_adjust_write(struct file *file, const char __user *buf,
959 				size_t count, loff_t *ppos)
960 {
961 	struct task_struct *task = proc_task(file->f_dentry->d_inode);
962 	char buffer[8], *end;
963 	int oom_adjust;
964 
965 	if (!capable(CAP_SYS_RESOURCE))
966 		return -EPERM;
967 	memset(buffer, 0, 8);
968 	if (count > 6)
969 		count = 6;
970 	if (copy_from_user(buffer, buf, count))
971 		return -EFAULT;
972 	oom_adjust = simple_strtol(buffer, &end, 0);
973 	if ((oom_adjust < -16 || oom_adjust > 15) && oom_adjust != OOM_DISABLE)
974 		return -EINVAL;
975 	if (*end == '\n')
976 		end++;
977 	task->oomkilladj = oom_adjust;
978 	if (end - buffer == 0)
979 		return -EIO;
980 	return end - buffer;
981 }
982 
983 static struct file_operations proc_oom_adjust_operations = {
984 	.read		= oom_adjust_read,
985 	.write		= oom_adjust_write,
986 };
987 
988 static struct inode_operations proc_mem_inode_operations = {
989 	.permission	= proc_permission,
990 };
991 
992 #ifdef CONFIG_AUDITSYSCALL
993 #define TMPBUFLEN 21
994 static ssize_t proc_loginuid_read(struct file * file, char __user * buf,
995 				  size_t count, loff_t *ppos)
996 {
997 	struct inode * inode = file->f_dentry->d_inode;
998 	struct task_struct *task = proc_task(inode);
999 	ssize_t length;
1000 	char tmpbuf[TMPBUFLEN];
1001 
1002 	length = scnprintf(tmpbuf, TMPBUFLEN, "%u",
1003 				audit_get_loginuid(task->audit_context));
1004 	return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
1005 }
1006 
1007 static ssize_t proc_loginuid_write(struct file * file, const char __user * buf,
1008 				   size_t count, loff_t *ppos)
1009 {
1010 	struct inode * inode = file->f_dentry->d_inode;
1011 	char *page, *tmp;
1012 	ssize_t length;
1013 	struct task_struct *task = proc_task(inode);
1014 	uid_t loginuid;
1015 
1016 	if (!capable(CAP_AUDIT_CONTROL))
1017 		return -EPERM;
1018 
1019 	if (current != task)
1020 		return -EPERM;
1021 
1022 	if (count >= PAGE_SIZE)
1023 		count = PAGE_SIZE - 1;
1024 
1025 	if (*ppos != 0) {
1026 		/* No partial writes. */
1027 		return -EINVAL;
1028 	}
1029 	page = (char*)__get_free_page(GFP_USER);
1030 	if (!page)
1031 		return -ENOMEM;
1032 	length = -EFAULT;
1033 	if (copy_from_user(page, buf, count))
1034 		goto out_free_page;
1035 
1036 	page[count] = '\0';
1037 	loginuid = simple_strtoul(page, &tmp, 10);
1038 	if (tmp == page) {
1039 		length = -EINVAL;
1040 		goto out_free_page;
1041 
1042 	}
1043 	length = audit_set_loginuid(task, loginuid);
1044 	if (likely(length == 0))
1045 		length = count;
1046 
1047 out_free_page:
1048 	free_page((unsigned long) page);
1049 	return length;
1050 }
1051 
1052 static struct file_operations proc_loginuid_operations = {
1053 	.read		= proc_loginuid_read,
1054 	.write		= proc_loginuid_write,
1055 };
1056 #endif
1057 
1058 #ifdef CONFIG_SECCOMP
1059 static ssize_t seccomp_read(struct file *file, char __user *buf,
1060 			    size_t count, loff_t *ppos)
1061 {
1062 	struct task_struct *tsk = proc_task(file->f_dentry->d_inode);
1063 	char __buf[20];
1064 	loff_t __ppos = *ppos;
1065 	size_t len;
1066 
1067 	/* no need to print the trailing zero, so use only len */
1068 	len = sprintf(__buf, "%u\n", tsk->seccomp.mode);
1069 	if (__ppos >= len)
1070 		return 0;
1071 	if (count > len - __ppos)
1072 		count = len - __ppos;
1073 	if (copy_to_user(buf, __buf + __ppos, count))
1074 		return -EFAULT;
1075 	*ppos = __ppos + count;
1076 	return count;
1077 }
1078 
1079 static ssize_t seccomp_write(struct file *file, const char __user *buf,
1080 			     size_t count, loff_t *ppos)
1081 {
1082 	struct task_struct *tsk = proc_task(file->f_dentry->d_inode);
1083 	char __buf[20], *end;
1084 	unsigned int seccomp_mode;
1085 
1086 	/* can set it only once to be even more secure */
1087 	if (unlikely(tsk->seccomp.mode))
1088 		return -EPERM;
1089 
1090 	memset(__buf, 0, sizeof(__buf));
1091 	count = min(count, sizeof(__buf) - 1);
1092 	if (copy_from_user(__buf, buf, count))
1093 		return -EFAULT;
1094 	seccomp_mode = simple_strtoul(__buf, &end, 0);
1095 	if (*end == '\n')
1096 		end++;
1097 	if (seccomp_mode && seccomp_mode <= NR_SECCOMP_MODES) {
1098 		tsk->seccomp.mode = seccomp_mode;
1099 		set_tsk_thread_flag(tsk, TIF_SECCOMP);
1100 	} else
1101 		return -EINVAL;
1102 	if (unlikely(!(end - __buf)))
1103 		return -EIO;
1104 	return end - __buf;
1105 }
1106 
1107 static struct file_operations proc_seccomp_operations = {
1108 	.read		= seccomp_read,
1109 	.write		= seccomp_write,
1110 };
1111 #endif /* CONFIG_SECCOMP */
1112 
1113 static void *proc_pid_follow_link(struct dentry *dentry, struct nameidata *nd)
1114 {
1115 	struct inode *inode = dentry->d_inode;
1116 	int error = -EACCES;
1117 
1118 	/* We don't need a base pointer in the /proc filesystem */
1119 	path_release(nd);
1120 
1121 	if (current->fsuid != inode->i_uid && !capable(CAP_DAC_OVERRIDE))
1122 		goto out;
1123 	error = proc_check_root(inode);
1124 	if (error)
1125 		goto out;
1126 
1127 	error = PROC_I(inode)->op.proc_get_link(inode, &nd->dentry, &nd->mnt);
1128 	nd->last_type = LAST_BIND;
1129 out:
1130 	return ERR_PTR(error);
1131 }
1132 
1133 static int do_proc_readlink(struct dentry *dentry, struct vfsmount *mnt,
1134 			    char __user *buffer, int buflen)
1135 {
1136 	struct inode * inode;
1137 	char *tmp = (char*)__get_free_page(GFP_KERNEL), *path;
1138 	int len;
1139 
1140 	if (!tmp)
1141 		return -ENOMEM;
1142 
1143 	inode = dentry->d_inode;
1144 	path = d_path(dentry, mnt, tmp, PAGE_SIZE);
1145 	len = PTR_ERR(path);
1146 	if (IS_ERR(path))
1147 		goto out;
1148 	len = tmp + PAGE_SIZE - 1 - path;
1149 
1150 	if (len > buflen)
1151 		len = buflen;
1152 	if (copy_to_user(buffer, path, len))
1153 		len = -EFAULT;
1154  out:
1155 	free_page((unsigned long)tmp);
1156 	return len;
1157 }
1158 
1159 static int proc_pid_readlink(struct dentry * dentry, char __user * buffer, int buflen)
1160 {
1161 	int error = -EACCES;
1162 	struct inode *inode = dentry->d_inode;
1163 	struct dentry *de;
1164 	struct vfsmount *mnt = NULL;
1165 
1166 	lock_kernel();
1167 
1168 	if (current->fsuid != inode->i_uid && !capable(CAP_DAC_OVERRIDE))
1169 		goto out;
1170 	error = proc_check_root(inode);
1171 	if (error)
1172 		goto out;
1173 
1174 	error = PROC_I(inode)->op.proc_get_link(inode, &de, &mnt);
1175 	if (error)
1176 		goto out;
1177 
1178 	error = do_proc_readlink(de, mnt, buffer, buflen);
1179 	dput(de);
1180 	mntput(mnt);
1181 out:
1182 	unlock_kernel();
1183 	return error;
1184 }
1185 
1186 static struct inode_operations proc_pid_link_inode_operations = {
1187 	.readlink	= proc_pid_readlink,
1188 	.follow_link	= proc_pid_follow_link
1189 };
1190 
1191 #define NUMBUF 10
1192 
1193 static int proc_readfd(struct file * filp, void * dirent, filldir_t filldir)
1194 {
1195 	struct inode *inode = filp->f_dentry->d_inode;
1196 	struct task_struct *p = proc_task(inode);
1197 	unsigned int fd, tid, ino;
1198 	int retval;
1199 	char buf[NUMBUF];
1200 	struct files_struct * files;
1201 	struct fdtable *fdt;
1202 
1203 	retval = -ENOENT;
1204 	if (!pid_alive(p))
1205 		goto out;
1206 	retval = 0;
1207 	tid = p->pid;
1208 
1209 	fd = filp->f_pos;
1210 	switch (fd) {
1211 		case 0:
1212 			if (filldir(dirent, ".", 1, 0, inode->i_ino, DT_DIR) < 0)
1213 				goto out;
1214 			filp->f_pos++;
1215 		case 1:
1216 			ino = fake_ino(tid, PROC_TID_INO);
1217 			if (filldir(dirent, "..", 2, 1, ino, DT_DIR) < 0)
1218 				goto out;
1219 			filp->f_pos++;
1220 		default:
1221 			files = get_files_struct(p);
1222 			if (!files)
1223 				goto out;
1224 			rcu_read_lock();
1225 			fdt = files_fdtable(files);
1226 			for (fd = filp->f_pos-2;
1227 			     fd < fdt->max_fds;
1228 			     fd++, filp->f_pos++) {
1229 				unsigned int i,j;
1230 
1231 				if (!fcheck_files(files, fd))
1232 					continue;
1233 				rcu_read_unlock();
1234 
1235 				j = NUMBUF;
1236 				i = fd;
1237 				do {
1238 					j--;
1239 					buf[j] = '0' + (i % 10);
1240 					i /= 10;
1241 				} while (i);
1242 
1243 				ino = fake_ino(tid, PROC_TID_FD_DIR + fd);
1244 				if (filldir(dirent, buf+j, NUMBUF-j, fd+2, ino, DT_LNK) < 0) {
1245 					rcu_read_lock();
1246 					break;
1247 				}
1248 				rcu_read_lock();
1249 			}
1250 			rcu_read_unlock();
1251 			put_files_struct(files);
1252 	}
1253 out:
1254 	return retval;
1255 }
1256 
1257 static int proc_pident_readdir(struct file *filp,
1258 		void *dirent, filldir_t filldir,
1259 		struct pid_entry *ents, unsigned int nents)
1260 {
1261 	int i;
1262 	int pid;
1263 	struct dentry *dentry = filp->f_dentry;
1264 	struct inode *inode = dentry->d_inode;
1265 	struct pid_entry *p;
1266 	ino_t ino;
1267 	int ret;
1268 
1269 	ret = -ENOENT;
1270 	if (!pid_alive(proc_task(inode)))
1271 		goto out;
1272 
1273 	ret = 0;
1274 	pid = proc_task(inode)->pid;
1275 	i = filp->f_pos;
1276 	switch (i) {
1277 	case 0:
1278 		ino = inode->i_ino;
1279 		if (filldir(dirent, ".", 1, i, ino, DT_DIR) < 0)
1280 			goto out;
1281 		i++;
1282 		filp->f_pos++;
1283 		/* fall through */
1284 	case 1:
1285 		ino = parent_ino(dentry);
1286 		if (filldir(dirent, "..", 2, i, ino, DT_DIR) < 0)
1287 			goto out;
1288 		i++;
1289 		filp->f_pos++;
1290 		/* fall through */
1291 	default:
1292 		i -= 2;
1293 		if (i >= nents) {
1294 			ret = 1;
1295 			goto out;
1296 		}
1297 		p = ents + i;
1298 		while (p->name) {
1299 			if (filldir(dirent, p->name, p->len, filp->f_pos,
1300 				    fake_ino(pid, p->type), p->mode >> 12) < 0)
1301 				goto out;
1302 			filp->f_pos++;
1303 			p++;
1304 		}
1305 	}
1306 
1307 	ret = 1;
1308 out:
1309 	return ret;
1310 }
1311 
1312 static int proc_tgid_base_readdir(struct file * filp,
1313 			     void * dirent, filldir_t filldir)
1314 {
1315 	return proc_pident_readdir(filp,dirent,filldir,
1316 				   tgid_base_stuff,ARRAY_SIZE(tgid_base_stuff));
1317 }
1318 
1319 static int proc_tid_base_readdir(struct file * filp,
1320 			     void * dirent, filldir_t filldir)
1321 {
1322 	return proc_pident_readdir(filp,dirent,filldir,
1323 				   tid_base_stuff,ARRAY_SIZE(tid_base_stuff));
1324 }
1325 
1326 /* building an inode */
1327 
1328 static int task_dumpable(struct task_struct *task)
1329 {
1330 	int dumpable = 0;
1331 	struct mm_struct *mm;
1332 
1333 	task_lock(task);
1334 	mm = task->mm;
1335 	if (mm)
1336 		dumpable = mm->dumpable;
1337 	task_unlock(task);
1338 	if(dumpable == 1)
1339 		return 1;
1340 	return 0;
1341 }
1342 
1343 
1344 static struct inode *proc_pid_make_inode(struct super_block * sb, struct task_struct *task, int ino)
1345 {
1346 	struct inode * inode;
1347 	struct proc_inode *ei;
1348 
1349 	/* We need a new inode */
1350 
1351 	inode = new_inode(sb);
1352 	if (!inode)
1353 		goto out;
1354 
1355 	/* Common stuff */
1356 	ei = PROC_I(inode);
1357 	ei->task = NULL;
1358 	inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
1359 	inode->i_ino = fake_ino(task->pid, ino);
1360 
1361 	if (!pid_alive(task))
1362 		goto out_unlock;
1363 
1364 	/*
1365 	 * grab the reference to task.
1366 	 */
1367 	get_task_struct(task);
1368 	ei->task = task;
1369 	ei->type = ino;
1370 	inode->i_uid = 0;
1371 	inode->i_gid = 0;
1372 	if (ino == PROC_TGID_INO || ino == PROC_TID_INO || task_dumpable(task)) {
1373 		inode->i_uid = task->euid;
1374 		inode->i_gid = task->egid;
1375 	}
1376 	security_task_to_inode(task, inode);
1377 
1378 out:
1379 	return inode;
1380 
1381 out_unlock:
1382 	ei->pde = NULL;
1383 	iput(inode);
1384 	return NULL;
1385 }
1386 
1387 /* dentry stuff */
1388 
1389 /*
1390  *	Exceptional case: normally we are not allowed to unhash a busy
1391  * directory. In this case, however, we can do it - no aliasing problems
1392  * due to the way we treat inodes.
1393  *
1394  * Rewrite the inode's ownerships here because the owning task may have
1395  * performed a setuid(), etc.
1396  */
1397 static int pid_revalidate(struct dentry *dentry, struct nameidata *nd)
1398 {
1399 	struct inode *inode = dentry->d_inode;
1400 	struct task_struct *task = proc_task(inode);
1401 	if (pid_alive(task)) {
1402 		if (proc_type(inode) == PROC_TGID_INO || proc_type(inode) == PROC_TID_INO || task_dumpable(task)) {
1403 			inode->i_uid = task->euid;
1404 			inode->i_gid = task->egid;
1405 		} else {
1406 			inode->i_uid = 0;
1407 			inode->i_gid = 0;
1408 		}
1409 		security_task_to_inode(task, inode);
1410 		return 1;
1411 	}
1412 	d_drop(dentry);
1413 	return 0;
1414 }
1415 
1416 static int tid_fd_revalidate(struct dentry *dentry, struct nameidata *nd)
1417 {
1418 	struct inode *inode = dentry->d_inode;
1419 	struct task_struct *task = proc_task(inode);
1420 	int fd = proc_type(inode) - PROC_TID_FD_DIR;
1421 	struct files_struct *files;
1422 
1423 	files = get_files_struct(task);
1424 	if (files) {
1425 		rcu_read_lock();
1426 		if (fcheck_files(files, fd)) {
1427 			rcu_read_unlock();
1428 			put_files_struct(files);
1429 			if (task_dumpable(task)) {
1430 				inode->i_uid = task->euid;
1431 				inode->i_gid = task->egid;
1432 			} else {
1433 				inode->i_uid = 0;
1434 				inode->i_gid = 0;
1435 			}
1436 			security_task_to_inode(task, inode);
1437 			return 1;
1438 		}
1439 		rcu_read_unlock();
1440 		put_files_struct(files);
1441 	}
1442 	d_drop(dentry);
1443 	return 0;
1444 }
1445 
1446 static void pid_base_iput(struct dentry *dentry, struct inode *inode)
1447 {
1448 	struct task_struct *task = proc_task(inode);
1449 	spin_lock(&task->proc_lock);
1450 	if (task->proc_dentry == dentry)
1451 		task->proc_dentry = NULL;
1452 	spin_unlock(&task->proc_lock);
1453 	iput(inode);
1454 }
1455 
1456 static int pid_delete_dentry(struct dentry * dentry)
1457 {
1458 	/* Is the task we represent dead?
1459 	 * If so, then don't put the dentry on the lru list,
1460 	 * kill it immediately.
1461 	 */
1462 	return !pid_alive(proc_task(dentry->d_inode));
1463 }
1464 
1465 static struct dentry_operations tid_fd_dentry_operations =
1466 {
1467 	.d_revalidate	= tid_fd_revalidate,
1468 	.d_delete	= pid_delete_dentry,
1469 };
1470 
1471 static struct dentry_operations pid_dentry_operations =
1472 {
1473 	.d_revalidate	= pid_revalidate,
1474 	.d_delete	= pid_delete_dentry,
1475 };
1476 
1477 static struct dentry_operations pid_base_dentry_operations =
1478 {
1479 	.d_revalidate	= pid_revalidate,
1480 	.d_iput		= pid_base_iput,
1481 	.d_delete	= pid_delete_dentry,
1482 };
1483 
1484 /* Lookups */
1485 
1486 static unsigned name_to_int(struct dentry *dentry)
1487 {
1488 	const char *name = dentry->d_name.name;
1489 	int len = dentry->d_name.len;
1490 	unsigned n = 0;
1491 
1492 	if (len > 1 && *name == '0')
1493 		goto out;
1494 	while (len-- > 0) {
1495 		unsigned c = *name++ - '0';
1496 		if (c > 9)
1497 			goto out;
1498 		if (n >= (~0U-9)/10)
1499 			goto out;
1500 		n *= 10;
1501 		n += c;
1502 	}
1503 	return n;
1504 out:
1505 	return ~0U;
1506 }
1507 
1508 /* SMP-safe */
1509 static struct dentry *proc_lookupfd(struct inode * dir, struct dentry * dentry, struct nameidata *nd)
1510 {
1511 	struct task_struct *task = proc_task(dir);
1512 	unsigned fd = name_to_int(dentry);
1513 	struct file * file;
1514 	struct files_struct * files;
1515 	struct inode *inode;
1516 	struct proc_inode *ei;
1517 
1518 	if (fd == ~0U)
1519 		goto out;
1520 	if (!pid_alive(task))
1521 		goto out;
1522 
1523 	inode = proc_pid_make_inode(dir->i_sb, task, PROC_TID_FD_DIR+fd);
1524 	if (!inode)
1525 		goto out;
1526 	ei = PROC_I(inode);
1527 	files = get_files_struct(task);
1528 	if (!files)
1529 		goto out_unlock;
1530 	inode->i_mode = S_IFLNK;
1531 
1532 	/*
1533 	 * We are not taking a ref to the file structure, so we must
1534 	 * hold ->file_lock.
1535 	 */
1536 	spin_lock(&files->file_lock);
1537 	file = fcheck_files(files, fd);
1538 	if (!file)
1539 		goto out_unlock2;
1540 	if (file->f_mode & 1)
1541 		inode->i_mode |= S_IRUSR | S_IXUSR;
1542 	if (file->f_mode & 2)
1543 		inode->i_mode |= S_IWUSR | S_IXUSR;
1544 	spin_unlock(&files->file_lock);
1545 	put_files_struct(files);
1546 	inode->i_op = &proc_pid_link_inode_operations;
1547 	inode->i_size = 64;
1548 	ei->op.proc_get_link = proc_fd_link;
1549 	dentry->d_op = &tid_fd_dentry_operations;
1550 	d_add(dentry, inode);
1551 	return NULL;
1552 
1553 out_unlock2:
1554 	spin_unlock(&files->file_lock);
1555 	put_files_struct(files);
1556 out_unlock:
1557 	iput(inode);
1558 out:
1559 	return ERR_PTR(-ENOENT);
1560 }
1561 
1562 static int proc_task_readdir(struct file * filp, void * dirent, filldir_t filldir);
1563 static struct dentry *proc_task_lookup(struct inode *dir, struct dentry * dentry, struct nameidata *nd);
1564 
1565 static struct file_operations proc_fd_operations = {
1566 	.read		= generic_read_dir,
1567 	.readdir	= proc_readfd,
1568 };
1569 
1570 static struct file_operations proc_task_operations = {
1571 	.read		= generic_read_dir,
1572 	.readdir	= proc_task_readdir,
1573 };
1574 
1575 /*
1576  * proc directories can do almost nothing..
1577  */
1578 static struct inode_operations proc_fd_inode_operations = {
1579 	.lookup		= proc_lookupfd,
1580 	.permission	= proc_permission,
1581 };
1582 
1583 static struct inode_operations proc_task_inode_operations = {
1584 	.lookup		= proc_task_lookup,
1585 	.permission	= proc_task_permission,
1586 };
1587 
1588 #ifdef CONFIG_SECURITY
1589 static ssize_t proc_pid_attr_read(struct file * file, char __user * buf,
1590 				  size_t count, loff_t *ppos)
1591 {
1592 	struct inode * inode = file->f_dentry->d_inode;
1593 	unsigned long page;
1594 	ssize_t length;
1595 	struct task_struct *task = proc_task(inode);
1596 
1597 	if (count > PAGE_SIZE)
1598 		count = PAGE_SIZE;
1599 	if (!(page = __get_free_page(GFP_KERNEL)))
1600 		return -ENOMEM;
1601 
1602 	length = security_getprocattr(task,
1603 				      (char*)file->f_dentry->d_name.name,
1604 				      (void*)page, count);
1605 	if (length >= 0)
1606 		length = simple_read_from_buffer(buf, count, ppos, (char *)page, length);
1607 	free_page(page);
1608 	return length;
1609 }
1610 
1611 static ssize_t proc_pid_attr_write(struct file * file, const char __user * buf,
1612 				   size_t count, loff_t *ppos)
1613 {
1614 	struct inode * inode = file->f_dentry->d_inode;
1615 	char *page;
1616 	ssize_t length;
1617 	struct task_struct *task = proc_task(inode);
1618 
1619 	if (count > PAGE_SIZE)
1620 		count = PAGE_SIZE;
1621 	if (*ppos != 0) {
1622 		/* No partial writes. */
1623 		return -EINVAL;
1624 	}
1625 	page = (char*)__get_free_page(GFP_USER);
1626 	if (!page)
1627 		return -ENOMEM;
1628 	length = -EFAULT;
1629 	if (copy_from_user(page, buf, count))
1630 		goto out;
1631 
1632 	length = security_setprocattr(task,
1633 				      (char*)file->f_dentry->d_name.name,
1634 				      (void*)page, count);
1635 out:
1636 	free_page((unsigned long) page);
1637 	return length;
1638 }
1639 
1640 static struct file_operations proc_pid_attr_operations = {
1641 	.read		= proc_pid_attr_read,
1642 	.write		= proc_pid_attr_write,
1643 };
1644 
1645 static struct file_operations proc_tid_attr_operations;
1646 static struct inode_operations proc_tid_attr_inode_operations;
1647 static struct file_operations proc_tgid_attr_operations;
1648 static struct inode_operations proc_tgid_attr_inode_operations;
1649 #endif
1650 
1651 static int get_tid_list(int index, unsigned int *tids, struct inode *dir);
1652 
1653 /* SMP-safe */
1654 static struct dentry *proc_pident_lookup(struct inode *dir,
1655 					 struct dentry *dentry,
1656 					 struct pid_entry *ents)
1657 {
1658 	struct inode *inode;
1659 	int error;
1660 	struct task_struct *task = proc_task(dir);
1661 	struct pid_entry *p;
1662 	struct proc_inode *ei;
1663 
1664 	error = -ENOENT;
1665 	inode = NULL;
1666 
1667 	if (!pid_alive(task))
1668 		goto out;
1669 
1670 	for (p = ents; p->name; p++) {
1671 		if (p->len != dentry->d_name.len)
1672 			continue;
1673 		if (!memcmp(dentry->d_name.name, p->name, p->len))
1674 			break;
1675 	}
1676 	if (!p->name)
1677 		goto out;
1678 
1679 	error = -EINVAL;
1680 	inode = proc_pid_make_inode(dir->i_sb, task, p->type);
1681 	if (!inode)
1682 		goto out;
1683 
1684 	ei = PROC_I(inode);
1685 	inode->i_mode = p->mode;
1686 	/*
1687 	 * Yes, it does not scale. And it should not. Don't add
1688 	 * new entries into /proc/<tgid>/ without very good reasons.
1689 	 */
1690 	switch(p->type) {
1691 		case PROC_TGID_TASK:
1692 			inode->i_nlink = 2 + get_tid_list(2, NULL, dir);
1693 			inode->i_op = &proc_task_inode_operations;
1694 			inode->i_fop = &proc_task_operations;
1695 			break;
1696 		case PROC_TID_FD:
1697 		case PROC_TGID_FD:
1698 			inode->i_nlink = 2;
1699 			inode->i_op = &proc_fd_inode_operations;
1700 			inode->i_fop = &proc_fd_operations;
1701 			break;
1702 		case PROC_TID_EXE:
1703 		case PROC_TGID_EXE:
1704 			inode->i_op = &proc_pid_link_inode_operations;
1705 			ei->op.proc_get_link = proc_exe_link;
1706 			break;
1707 		case PROC_TID_CWD:
1708 		case PROC_TGID_CWD:
1709 			inode->i_op = &proc_pid_link_inode_operations;
1710 			ei->op.proc_get_link = proc_cwd_link;
1711 			break;
1712 		case PROC_TID_ROOT:
1713 		case PROC_TGID_ROOT:
1714 			inode->i_op = &proc_pid_link_inode_operations;
1715 			ei->op.proc_get_link = proc_root_link;
1716 			break;
1717 		case PROC_TID_ENVIRON:
1718 		case PROC_TGID_ENVIRON:
1719 			inode->i_fop = &proc_info_file_operations;
1720 			ei->op.proc_read = proc_pid_environ;
1721 			break;
1722 		case PROC_TID_AUXV:
1723 		case PROC_TGID_AUXV:
1724 			inode->i_fop = &proc_info_file_operations;
1725 			ei->op.proc_read = proc_pid_auxv;
1726 			break;
1727 		case PROC_TID_STATUS:
1728 		case PROC_TGID_STATUS:
1729 			inode->i_fop = &proc_info_file_operations;
1730 			ei->op.proc_read = proc_pid_status;
1731 			break;
1732 		case PROC_TID_STAT:
1733 			inode->i_fop = &proc_info_file_operations;
1734 			ei->op.proc_read = proc_tid_stat;
1735 			break;
1736 		case PROC_TGID_STAT:
1737 			inode->i_fop = &proc_info_file_operations;
1738 			ei->op.proc_read = proc_tgid_stat;
1739 			break;
1740 		case PROC_TID_CMDLINE:
1741 		case PROC_TGID_CMDLINE:
1742 			inode->i_fop = &proc_info_file_operations;
1743 			ei->op.proc_read = proc_pid_cmdline;
1744 			break;
1745 		case PROC_TID_STATM:
1746 		case PROC_TGID_STATM:
1747 			inode->i_fop = &proc_info_file_operations;
1748 			ei->op.proc_read = proc_pid_statm;
1749 			break;
1750 		case PROC_TID_MAPS:
1751 		case PROC_TGID_MAPS:
1752 			inode->i_fop = &proc_maps_operations;
1753 			break;
1754 #ifdef CONFIG_NUMA
1755 		case PROC_TID_NUMA_MAPS:
1756 		case PROC_TGID_NUMA_MAPS:
1757 			inode->i_fop = &proc_numa_maps_operations;
1758 			break;
1759 #endif
1760 		case PROC_TID_MEM:
1761 		case PROC_TGID_MEM:
1762 			inode->i_op = &proc_mem_inode_operations;
1763 			inode->i_fop = &proc_mem_operations;
1764 			break;
1765 #ifdef CONFIG_SECCOMP
1766 		case PROC_TID_SECCOMP:
1767 		case PROC_TGID_SECCOMP:
1768 			inode->i_fop = &proc_seccomp_operations;
1769 			break;
1770 #endif /* CONFIG_SECCOMP */
1771 		case PROC_TID_MOUNTS:
1772 		case PROC_TGID_MOUNTS:
1773 			inode->i_fop = &proc_mounts_operations;
1774 			break;
1775 #ifdef CONFIG_MMU
1776 		case PROC_TID_SMAPS:
1777 		case PROC_TGID_SMAPS:
1778 			inode->i_fop = &proc_smaps_operations;
1779 			break;
1780 #endif
1781 		case PROC_TID_MOUNTSTATS:
1782 		case PROC_TGID_MOUNTSTATS:
1783 			inode->i_fop = &proc_mountstats_operations;
1784 			break;
1785 #ifdef CONFIG_SECURITY
1786 		case PROC_TID_ATTR:
1787 			inode->i_nlink = 2;
1788 			inode->i_op = &proc_tid_attr_inode_operations;
1789 			inode->i_fop = &proc_tid_attr_operations;
1790 			break;
1791 		case PROC_TGID_ATTR:
1792 			inode->i_nlink = 2;
1793 			inode->i_op = &proc_tgid_attr_inode_operations;
1794 			inode->i_fop = &proc_tgid_attr_operations;
1795 			break;
1796 		case PROC_TID_ATTR_CURRENT:
1797 		case PROC_TGID_ATTR_CURRENT:
1798 		case PROC_TID_ATTR_PREV:
1799 		case PROC_TGID_ATTR_PREV:
1800 		case PROC_TID_ATTR_EXEC:
1801 		case PROC_TGID_ATTR_EXEC:
1802 		case PROC_TID_ATTR_FSCREATE:
1803 		case PROC_TGID_ATTR_FSCREATE:
1804 			inode->i_fop = &proc_pid_attr_operations;
1805 			break;
1806 #endif
1807 #ifdef CONFIG_KALLSYMS
1808 		case PROC_TID_WCHAN:
1809 		case PROC_TGID_WCHAN:
1810 			inode->i_fop = &proc_info_file_operations;
1811 			ei->op.proc_read = proc_pid_wchan;
1812 			break;
1813 #endif
1814 #ifdef CONFIG_SCHEDSTATS
1815 		case PROC_TID_SCHEDSTAT:
1816 		case PROC_TGID_SCHEDSTAT:
1817 			inode->i_fop = &proc_info_file_operations;
1818 			ei->op.proc_read = proc_pid_schedstat;
1819 			break;
1820 #endif
1821 #ifdef CONFIG_CPUSETS
1822 		case PROC_TID_CPUSET:
1823 		case PROC_TGID_CPUSET:
1824 			inode->i_fop = &proc_cpuset_operations;
1825 			break;
1826 #endif
1827 		case PROC_TID_OOM_SCORE:
1828 		case PROC_TGID_OOM_SCORE:
1829 			inode->i_fop = &proc_info_file_operations;
1830 			ei->op.proc_read = proc_oom_score;
1831 			break;
1832 		case PROC_TID_OOM_ADJUST:
1833 		case PROC_TGID_OOM_ADJUST:
1834 			inode->i_fop = &proc_oom_adjust_operations;
1835 			break;
1836 #ifdef CONFIG_AUDITSYSCALL
1837 		case PROC_TID_LOGINUID:
1838 		case PROC_TGID_LOGINUID:
1839 			inode->i_fop = &proc_loginuid_operations;
1840 			break;
1841 #endif
1842 		default:
1843 			printk("procfs: impossible type (%d)",p->type);
1844 			iput(inode);
1845 			return ERR_PTR(-EINVAL);
1846 	}
1847 	dentry->d_op = &pid_dentry_operations;
1848 	d_add(dentry, inode);
1849 	return NULL;
1850 
1851 out:
1852 	return ERR_PTR(error);
1853 }
1854 
1855 static struct dentry *proc_tgid_base_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd){
1856 	return proc_pident_lookup(dir, dentry, tgid_base_stuff);
1857 }
1858 
1859 static struct dentry *proc_tid_base_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd){
1860 	return proc_pident_lookup(dir, dentry, tid_base_stuff);
1861 }
1862 
1863 static struct file_operations proc_tgid_base_operations = {
1864 	.read		= generic_read_dir,
1865 	.readdir	= proc_tgid_base_readdir,
1866 };
1867 
1868 static struct file_operations proc_tid_base_operations = {
1869 	.read		= generic_read_dir,
1870 	.readdir	= proc_tid_base_readdir,
1871 };
1872 
1873 static struct inode_operations proc_tgid_base_inode_operations = {
1874 	.lookup		= proc_tgid_base_lookup,
1875 };
1876 
1877 static struct inode_operations proc_tid_base_inode_operations = {
1878 	.lookup		= proc_tid_base_lookup,
1879 };
1880 
1881 #ifdef CONFIG_SECURITY
1882 static int proc_tgid_attr_readdir(struct file * filp,
1883 			     void * dirent, filldir_t filldir)
1884 {
1885 	return proc_pident_readdir(filp,dirent,filldir,
1886 				   tgid_attr_stuff,ARRAY_SIZE(tgid_attr_stuff));
1887 }
1888 
1889 static int proc_tid_attr_readdir(struct file * filp,
1890 			     void * dirent, filldir_t filldir)
1891 {
1892 	return proc_pident_readdir(filp,dirent,filldir,
1893 				   tid_attr_stuff,ARRAY_SIZE(tid_attr_stuff));
1894 }
1895 
1896 static struct file_operations proc_tgid_attr_operations = {
1897 	.read		= generic_read_dir,
1898 	.readdir	= proc_tgid_attr_readdir,
1899 };
1900 
1901 static struct file_operations proc_tid_attr_operations = {
1902 	.read		= generic_read_dir,
1903 	.readdir	= proc_tid_attr_readdir,
1904 };
1905 
1906 static struct dentry *proc_tgid_attr_lookup(struct inode *dir,
1907 				struct dentry *dentry, struct nameidata *nd)
1908 {
1909 	return proc_pident_lookup(dir, dentry, tgid_attr_stuff);
1910 }
1911 
1912 static struct dentry *proc_tid_attr_lookup(struct inode *dir,
1913 				struct dentry *dentry, struct nameidata *nd)
1914 {
1915 	return proc_pident_lookup(dir, dentry, tid_attr_stuff);
1916 }
1917 
1918 static struct inode_operations proc_tgid_attr_inode_operations = {
1919 	.lookup		= proc_tgid_attr_lookup,
1920 };
1921 
1922 static struct inode_operations proc_tid_attr_inode_operations = {
1923 	.lookup		= proc_tid_attr_lookup,
1924 };
1925 #endif
1926 
1927 /*
1928  * /proc/self:
1929  */
1930 static int proc_self_readlink(struct dentry *dentry, char __user *buffer,
1931 			      int buflen)
1932 {
1933 	char tmp[30];
1934 	sprintf(tmp, "%d", current->tgid);
1935 	return vfs_readlink(dentry,buffer,buflen,tmp);
1936 }
1937 
1938 static void *proc_self_follow_link(struct dentry *dentry, struct nameidata *nd)
1939 {
1940 	char tmp[30];
1941 	sprintf(tmp, "%d", current->tgid);
1942 	return ERR_PTR(vfs_follow_link(nd,tmp));
1943 }
1944 
1945 static struct inode_operations proc_self_inode_operations = {
1946 	.readlink	= proc_self_readlink,
1947 	.follow_link	= proc_self_follow_link,
1948 };
1949 
1950 /**
1951  * proc_pid_unhash -  Unhash /proc/@pid entry from the dcache.
1952  * @p: task that should be flushed.
1953  *
1954  * Drops the /proc/@pid dcache entry from the hash chains.
1955  *
1956  * Dropping /proc/@pid entries and detach_pid must be synchroneous,
1957  * otherwise e.g. /proc/@pid/exe might point to the wrong executable,
1958  * if the pid value is immediately reused. This is enforced by
1959  * - caller must acquire spin_lock(p->proc_lock)
1960  * - must be called before detach_pid()
1961  * - proc_pid_lookup acquires proc_lock, and checks that
1962  *   the target is not dead by looking at the attach count
1963  *   of PIDTYPE_PID.
1964  */
1965 
1966 struct dentry *proc_pid_unhash(struct task_struct *p)
1967 {
1968 	struct dentry *proc_dentry;
1969 
1970 	proc_dentry = p->proc_dentry;
1971 	if (proc_dentry != NULL) {
1972 
1973 		spin_lock(&dcache_lock);
1974 		spin_lock(&proc_dentry->d_lock);
1975 		if (!d_unhashed(proc_dentry)) {
1976 			dget_locked(proc_dentry);
1977 			__d_drop(proc_dentry);
1978 			spin_unlock(&proc_dentry->d_lock);
1979 		} else {
1980 			spin_unlock(&proc_dentry->d_lock);
1981 			proc_dentry = NULL;
1982 		}
1983 		spin_unlock(&dcache_lock);
1984 	}
1985 	return proc_dentry;
1986 }
1987 
1988 /**
1989  * proc_pid_flush - recover memory used by stale /proc/@pid/x entries
1990  * @proc_dentry: directoy to prune.
1991  *
1992  * Shrink the /proc directory that was used by the just killed thread.
1993  */
1994 
1995 void proc_pid_flush(struct dentry *proc_dentry)
1996 {
1997 	might_sleep();
1998 	if(proc_dentry != NULL) {
1999 		shrink_dcache_parent(proc_dentry);
2000 		dput(proc_dentry);
2001 	}
2002 }
2003 
2004 /* SMP-safe */
2005 struct dentry *proc_pid_lookup(struct inode *dir, struct dentry * dentry, struct nameidata *nd)
2006 {
2007 	struct task_struct *task;
2008 	struct inode *inode;
2009 	struct proc_inode *ei;
2010 	unsigned tgid;
2011 	int died;
2012 
2013 	if (dentry->d_name.len == 4 && !memcmp(dentry->d_name.name,"self",4)) {
2014 		inode = new_inode(dir->i_sb);
2015 		if (!inode)
2016 			return ERR_PTR(-ENOMEM);
2017 		ei = PROC_I(inode);
2018 		inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
2019 		inode->i_ino = fake_ino(0, PROC_TGID_INO);
2020 		ei->pde = NULL;
2021 		inode->i_mode = S_IFLNK|S_IRWXUGO;
2022 		inode->i_uid = inode->i_gid = 0;
2023 		inode->i_size = 64;
2024 		inode->i_op = &proc_self_inode_operations;
2025 		d_add(dentry, inode);
2026 		return NULL;
2027 	}
2028 	tgid = name_to_int(dentry);
2029 	if (tgid == ~0U)
2030 		goto out;
2031 
2032 	read_lock(&tasklist_lock);
2033 	task = find_task_by_pid(tgid);
2034 	if (task)
2035 		get_task_struct(task);
2036 	read_unlock(&tasklist_lock);
2037 	if (!task)
2038 		goto out;
2039 
2040 	inode = proc_pid_make_inode(dir->i_sb, task, PROC_TGID_INO);
2041 
2042 
2043 	if (!inode) {
2044 		put_task_struct(task);
2045 		goto out;
2046 	}
2047 	inode->i_mode = S_IFDIR|S_IRUGO|S_IXUGO;
2048 	inode->i_op = &proc_tgid_base_inode_operations;
2049 	inode->i_fop = &proc_tgid_base_operations;
2050 	inode->i_flags|=S_IMMUTABLE;
2051 #ifdef CONFIG_SECURITY
2052 	inode->i_nlink = 5;
2053 #else
2054 	inode->i_nlink = 4;
2055 #endif
2056 
2057 	dentry->d_op = &pid_base_dentry_operations;
2058 
2059 	died = 0;
2060 	d_add(dentry, inode);
2061 	spin_lock(&task->proc_lock);
2062 	task->proc_dentry = dentry;
2063 	if (!pid_alive(task)) {
2064 		dentry = proc_pid_unhash(task);
2065 		died = 1;
2066 	}
2067 	spin_unlock(&task->proc_lock);
2068 
2069 	put_task_struct(task);
2070 	if (died) {
2071 		proc_pid_flush(dentry);
2072 		goto out;
2073 	}
2074 	return NULL;
2075 out:
2076 	return ERR_PTR(-ENOENT);
2077 }
2078 
2079 /* SMP-safe */
2080 static struct dentry *proc_task_lookup(struct inode *dir, struct dentry * dentry, struct nameidata *nd)
2081 {
2082 	struct task_struct *task;
2083 	struct task_struct *leader = proc_task(dir);
2084 	struct inode *inode;
2085 	unsigned tid;
2086 
2087 	tid = name_to_int(dentry);
2088 	if (tid == ~0U)
2089 		goto out;
2090 
2091 	read_lock(&tasklist_lock);
2092 	task = find_task_by_pid(tid);
2093 	if (task)
2094 		get_task_struct(task);
2095 	read_unlock(&tasklist_lock);
2096 	if (!task)
2097 		goto out;
2098 	if (leader->tgid != task->tgid)
2099 		goto out_drop_task;
2100 
2101 	inode = proc_pid_make_inode(dir->i_sb, task, PROC_TID_INO);
2102 
2103 
2104 	if (!inode)
2105 		goto out_drop_task;
2106 	inode->i_mode = S_IFDIR|S_IRUGO|S_IXUGO;
2107 	inode->i_op = &proc_tid_base_inode_operations;
2108 	inode->i_fop = &proc_tid_base_operations;
2109 	inode->i_flags|=S_IMMUTABLE;
2110 #ifdef CONFIG_SECURITY
2111 	inode->i_nlink = 4;
2112 #else
2113 	inode->i_nlink = 3;
2114 #endif
2115 
2116 	dentry->d_op = &pid_base_dentry_operations;
2117 
2118 	d_add(dentry, inode);
2119 
2120 	put_task_struct(task);
2121 	return NULL;
2122 out_drop_task:
2123 	put_task_struct(task);
2124 out:
2125 	return ERR_PTR(-ENOENT);
2126 }
2127 
2128 #define PROC_NUMBUF 10
2129 #define PROC_MAXPIDS 20
2130 
2131 /*
2132  * Get a few tgid's to return for filldir - we need to hold the
2133  * tasklist lock while doing this, and we must release it before
2134  * we actually do the filldir itself, so we use a temp buffer..
2135  */
2136 static int get_tgid_list(int index, unsigned long version, unsigned int *tgids)
2137 {
2138 	struct task_struct *p;
2139 	int nr_tgids = 0;
2140 
2141 	index--;
2142 	read_lock(&tasklist_lock);
2143 	p = NULL;
2144 	if (version) {
2145 		p = find_task_by_pid(version);
2146 		if (p && !thread_group_leader(p))
2147 			p = NULL;
2148 	}
2149 
2150 	if (p)
2151 		index = 0;
2152 	else
2153 		p = next_task(&init_task);
2154 
2155 	for ( ; p != &init_task; p = next_task(p)) {
2156 		int tgid = p->pid;
2157 		if (!pid_alive(p))
2158 			continue;
2159 		if (--index >= 0)
2160 			continue;
2161 		tgids[nr_tgids] = tgid;
2162 		nr_tgids++;
2163 		if (nr_tgids >= PROC_MAXPIDS)
2164 			break;
2165 	}
2166 	read_unlock(&tasklist_lock);
2167 	return nr_tgids;
2168 }
2169 
2170 /*
2171  * Get a few tid's to return for filldir - we need to hold the
2172  * tasklist lock while doing this, and we must release it before
2173  * we actually do the filldir itself, so we use a temp buffer..
2174  */
2175 static int get_tid_list(int index, unsigned int *tids, struct inode *dir)
2176 {
2177 	struct task_struct *leader_task = proc_task(dir);
2178 	struct task_struct *task = leader_task;
2179 	int nr_tids = 0;
2180 
2181 	index -= 2;
2182 	read_lock(&tasklist_lock);
2183 	/*
2184 	 * The starting point task (leader_task) might be an already
2185 	 * unlinked task, which cannot be used to access the task-list
2186 	 * via next_thread().
2187 	 */
2188 	if (pid_alive(task)) do {
2189 		int tid = task->pid;
2190 
2191 		if (--index >= 0)
2192 			continue;
2193 		if (tids != NULL)
2194 			tids[nr_tids] = tid;
2195 		nr_tids++;
2196 		if (nr_tids >= PROC_MAXPIDS)
2197 			break;
2198 	} while ((task = next_thread(task)) != leader_task);
2199 	read_unlock(&tasklist_lock);
2200 	return nr_tids;
2201 }
2202 
2203 /* for the /proc/ directory itself, after non-process stuff has been done */
2204 int proc_pid_readdir(struct file * filp, void * dirent, filldir_t filldir)
2205 {
2206 	unsigned int tgid_array[PROC_MAXPIDS];
2207 	char buf[PROC_NUMBUF];
2208 	unsigned int nr = filp->f_pos - FIRST_PROCESS_ENTRY;
2209 	unsigned int nr_tgids, i;
2210 	int next_tgid;
2211 
2212 	if (!nr) {
2213 		ino_t ino = fake_ino(0,PROC_TGID_INO);
2214 		if (filldir(dirent, "self", 4, filp->f_pos, ino, DT_LNK) < 0)
2215 			return 0;
2216 		filp->f_pos++;
2217 		nr++;
2218 	}
2219 
2220 	/* f_version caches the tgid value that the last readdir call couldn't
2221 	 * return. lseek aka telldir automagically resets f_version to 0.
2222 	 */
2223 	next_tgid = filp->f_version;
2224 	filp->f_version = 0;
2225 	for (;;) {
2226 		nr_tgids = get_tgid_list(nr, next_tgid, tgid_array);
2227 		if (!nr_tgids) {
2228 			/* no more entries ! */
2229 			break;
2230 		}
2231 		next_tgid = 0;
2232 
2233 		/* do not use the last found pid, reserve it for next_tgid */
2234 		if (nr_tgids == PROC_MAXPIDS) {
2235 			nr_tgids--;
2236 			next_tgid = tgid_array[nr_tgids];
2237 		}
2238 
2239 		for (i=0;i<nr_tgids;i++) {
2240 			int tgid = tgid_array[i];
2241 			ino_t ino = fake_ino(tgid,PROC_TGID_INO);
2242 			unsigned long j = PROC_NUMBUF;
2243 
2244 			do
2245 				buf[--j] = '0' + (tgid % 10);
2246 			while ((tgid /= 10) != 0);
2247 
2248 			if (filldir(dirent, buf+j, PROC_NUMBUF-j, filp->f_pos, ino, DT_DIR) < 0) {
2249 				/* returning this tgid failed, save it as the first
2250 				 * pid for the next readir call */
2251 				filp->f_version = tgid_array[i];
2252 				goto out;
2253 			}
2254 			filp->f_pos++;
2255 			nr++;
2256 		}
2257 	}
2258 out:
2259 	return 0;
2260 }
2261 
2262 /* for the /proc/TGID/task/ directories */
2263 static int proc_task_readdir(struct file * filp, void * dirent, filldir_t filldir)
2264 {
2265 	unsigned int tid_array[PROC_MAXPIDS];
2266 	char buf[PROC_NUMBUF];
2267 	unsigned int nr_tids, i;
2268 	struct dentry *dentry = filp->f_dentry;
2269 	struct inode *inode = dentry->d_inode;
2270 	int retval = -ENOENT;
2271 	ino_t ino;
2272 	unsigned long pos = filp->f_pos;  /* avoiding "long long" filp->f_pos */
2273 
2274 	if (!pid_alive(proc_task(inode)))
2275 		goto out;
2276 	retval = 0;
2277 
2278 	switch (pos) {
2279 	case 0:
2280 		ino = inode->i_ino;
2281 		if (filldir(dirent, ".", 1, pos, ino, DT_DIR) < 0)
2282 			goto out;
2283 		pos++;
2284 		/* fall through */
2285 	case 1:
2286 		ino = parent_ino(dentry);
2287 		if (filldir(dirent, "..", 2, pos, ino, DT_DIR) < 0)
2288 			goto out;
2289 		pos++;
2290 		/* fall through */
2291 	}
2292 
2293 	nr_tids = get_tid_list(pos, tid_array, inode);
2294 	inode->i_nlink = pos + nr_tids;
2295 
2296 	for (i = 0; i < nr_tids; i++) {
2297 		unsigned long j = PROC_NUMBUF;
2298 		int tid = tid_array[i];
2299 
2300 		ino = fake_ino(tid,PROC_TID_INO);
2301 
2302 		do
2303 			buf[--j] = '0' + (tid % 10);
2304 		while ((tid /= 10) != 0);
2305 
2306 		if (filldir(dirent, buf+j, PROC_NUMBUF-j, pos, ino, DT_DIR) < 0)
2307 			break;
2308 		pos++;
2309 	}
2310 out:
2311 	filp->f_pos = pos;
2312 	return retval;
2313 }
2314