xref: /linux/fs/proc/base.c (revision 54a8a2220c936a47840c9a3d74910c5a56fae2ed)
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/file.h>
59 #include <linux/string.h>
60 #include <linux/seq_file.h>
61 #include <linux/namei.h>
62 #include <linux/namespace.h>
63 #include <linux/mm.h>
64 #include <linux/smp_lock.h>
65 #include <linux/rcupdate.h>
66 #include <linux/kallsyms.h>
67 #include <linux/mount.h>
68 #include <linux/security.h>
69 #include <linux/ptrace.h>
70 #include <linux/seccomp.h>
71 #include <linux/cpuset.h>
72 #include <linux/audit.h>
73 #include "internal.h"
74 
75 /*
76  * For hysterical raisins we keep the same inumbers as in the old procfs.
77  * Feel free to change the macro below - just keep the range distinct from
78  * inumbers of the rest of procfs (currently those are in 0x0000--0xffff).
79  * As soon as we'll get a separate superblock we will be able to forget
80  * about magical ranges too.
81  */
82 
83 #define fake_ino(pid,ino) (((pid)<<16)|(ino))
84 
85 enum pid_directory_inos {
86 	PROC_TGID_INO = 2,
87 	PROC_TGID_TASK,
88 	PROC_TGID_STATUS,
89 	PROC_TGID_MEM,
90 #ifdef CONFIG_SECCOMP
91 	PROC_TGID_SECCOMP,
92 #endif
93 	PROC_TGID_CWD,
94 	PROC_TGID_ROOT,
95 	PROC_TGID_EXE,
96 	PROC_TGID_FD,
97 	PROC_TGID_ENVIRON,
98 	PROC_TGID_AUXV,
99 	PROC_TGID_CMDLINE,
100 	PROC_TGID_STAT,
101 	PROC_TGID_STATM,
102 	PROC_TGID_MAPS,
103 	PROC_TGID_NUMA_MAPS,
104 	PROC_TGID_MOUNTS,
105 	PROC_TGID_WCHAN,
106 	PROC_TGID_SMAPS,
107 #ifdef CONFIG_SCHEDSTATS
108 	PROC_TGID_SCHEDSTAT,
109 #endif
110 #ifdef CONFIG_CPUSETS
111 	PROC_TGID_CPUSET,
112 #endif
113 #ifdef CONFIG_SECURITY
114 	PROC_TGID_ATTR,
115 	PROC_TGID_ATTR_CURRENT,
116 	PROC_TGID_ATTR_PREV,
117 	PROC_TGID_ATTR_EXEC,
118 	PROC_TGID_ATTR_FSCREATE,
119 #endif
120 #ifdef CONFIG_AUDITSYSCALL
121 	PROC_TGID_LOGINUID,
122 #endif
123 	PROC_TGID_OOM_SCORE,
124 	PROC_TGID_OOM_ADJUST,
125 	PROC_TID_INO,
126 	PROC_TID_STATUS,
127 	PROC_TID_MEM,
128 #ifdef CONFIG_SECCOMP
129 	PROC_TID_SECCOMP,
130 #endif
131 	PROC_TID_CWD,
132 	PROC_TID_ROOT,
133 	PROC_TID_EXE,
134 	PROC_TID_FD,
135 	PROC_TID_ENVIRON,
136 	PROC_TID_AUXV,
137 	PROC_TID_CMDLINE,
138 	PROC_TID_STAT,
139 	PROC_TID_STATM,
140 	PROC_TID_MAPS,
141 	PROC_TID_NUMA_MAPS,
142 	PROC_TID_MOUNTS,
143 	PROC_TID_WCHAN,
144 	PROC_TID_SMAPS,
145 #ifdef CONFIG_SCHEDSTATS
146 	PROC_TID_SCHEDSTAT,
147 #endif
148 #ifdef CONFIG_CPUSETS
149 	PROC_TID_CPUSET,
150 #endif
151 #ifdef CONFIG_SECURITY
152 	PROC_TID_ATTR,
153 	PROC_TID_ATTR_CURRENT,
154 	PROC_TID_ATTR_PREV,
155 	PROC_TID_ATTR_EXEC,
156 	PROC_TID_ATTR_FSCREATE,
157 #endif
158 #ifdef CONFIG_AUDITSYSCALL
159 	PROC_TID_LOGINUID,
160 #endif
161 	PROC_TID_OOM_SCORE,
162 	PROC_TID_OOM_ADJUST,
163 
164 	/* Add new entries before this */
165 	PROC_TID_FD_DIR = 0x8000,	/* 0x8000-0xffff */
166 };
167 
168 struct pid_entry {
169 	int type;
170 	int len;
171 	char *name;
172 	mode_t mode;
173 };
174 
175 #define E(type,name,mode) {(type),sizeof(name)-1,(name),(mode)}
176 
177 static struct pid_entry tgid_base_stuff[] = {
178 	E(PROC_TGID_TASK,      "task",    S_IFDIR|S_IRUGO|S_IXUGO),
179 	E(PROC_TGID_FD,        "fd",      S_IFDIR|S_IRUSR|S_IXUSR),
180 	E(PROC_TGID_ENVIRON,   "environ", S_IFREG|S_IRUSR),
181 	E(PROC_TGID_AUXV,      "auxv",	  S_IFREG|S_IRUSR),
182 	E(PROC_TGID_STATUS,    "status",  S_IFREG|S_IRUGO),
183 	E(PROC_TGID_CMDLINE,   "cmdline", S_IFREG|S_IRUGO),
184 	E(PROC_TGID_STAT,      "stat",    S_IFREG|S_IRUGO),
185 	E(PROC_TGID_STATM,     "statm",   S_IFREG|S_IRUGO),
186 	E(PROC_TGID_MAPS,      "maps",    S_IFREG|S_IRUGO),
187 #ifdef CONFIG_NUMA
188 	E(PROC_TGID_NUMA_MAPS, "numa_maps", S_IFREG|S_IRUGO),
189 #endif
190 	E(PROC_TGID_MEM,       "mem",     S_IFREG|S_IRUSR|S_IWUSR),
191 #ifdef CONFIG_SECCOMP
192 	E(PROC_TGID_SECCOMP,   "seccomp", S_IFREG|S_IRUSR|S_IWUSR),
193 #endif
194 	E(PROC_TGID_CWD,       "cwd",     S_IFLNK|S_IRWXUGO),
195 	E(PROC_TGID_ROOT,      "root",    S_IFLNK|S_IRWXUGO),
196 	E(PROC_TGID_EXE,       "exe",     S_IFLNK|S_IRWXUGO),
197 	E(PROC_TGID_MOUNTS,    "mounts",  S_IFREG|S_IRUGO),
198 	E(PROC_TGID_SMAPS,     "smaps",   S_IFREG|S_IRUGO),
199 #ifdef CONFIG_SECURITY
200 	E(PROC_TGID_ATTR,      "attr",    S_IFDIR|S_IRUGO|S_IXUGO),
201 #endif
202 #ifdef CONFIG_KALLSYMS
203 	E(PROC_TGID_WCHAN,     "wchan",   S_IFREG|S_IRUGO),
204 #endif
205 #ifdef CONFIG_SCHEDSTATS
206 	E(PROC_TGID_SCHEDSTAT, "schedstat", S_IFREG|S_IRUGO),
207 #endif
208 #ifdef CONFIG_CPUSETS
209 	E(PROC_TGID_CPUSET,    "cpuset",  S_IFREG|S_IRUGO),
210 #endif
211 	E(PROC_TGID_OOM_SCORE, "oom_score",S_IFREG|S_IRUGO),
212 	E(PROC_TGID_OOM_ADJUST,"oom_adj", S_IFREG|S_IRUGO|S_IWUSR),
213 #ifdef CONFIG_AUDITSYSCALL
214 	E(PROC_TGID_LOGINUID, "loginuid", S_IFREG|S_IWUSR|S_IRUGO),
215 #endif
216 	{0,0,NULL,0}
217 };
218 static struct pid_entry tid_base_stuff[] = {
219 	E(PROC_TID_FD,         "fd",      S_IFDIR|S_IRUSR|S_IXUSR),
220 	E(PROC_TID_ENVIRON,    "environ", S_IFREG|S_IRUSR),
221 	E(PROC_TID_AUXV,       "auxv",	  S_IFREG|S_IRUSR),
222 	E(PROC_TID_STATUS,     "status",  S_IFREG|S_IRUGO),
223 	E(PROC_TID_CMDLINE,    "cmdline", S_IFREG|S_IRUGO),
224 	E(PROC_TID_STAT,       "stat",    S_IFREG|S_IRUGO),
225 	E(PROC_TID_STATM,      "statm",   S_IFREG|S_IRUGO),
226 	E(PROC_TID_MAPS,       "maps",    S_IFREG|S_IRUGO),
227 #ifdef CONFIG_NUMA
228 	E(PROC_TID_NUMA_MAPS,  "numa_maps",    S_IFREG|S_IRUGO),
229 #endif
230 	E(PROC_TID_MEM,        "mem",     S_IFREG|S_IRUSR|S_IWUSR),
231 #ifdef CONFIG_SECCOMP
232 	E(PROC_TID_SECCOMP,    "seccomp", S_IFREG|S_IRUSR|S_IWUSR),
233 #endif
234 	E(PROC_TID_CWD,        "cwd",     S_IFLNK|S_IRWXUGO),
235 	E(PROC_TID_ROOT,       "root",    S_IFLNK|S_IRWXUGO),
236 	E(PROC_TID_EXE,        "exe",     S_IFLNK|S_IRWXUGO),
237 	E(PROC_TID_MOUNTS,     "mounts",  S_IFREG|S_IRUGO),
238 	E(PROC_TID_SMAPS,      "smaps",   S_IFREG|S_IRUGO),
239 #ifdef CONFIG_SECURITY
240 	E(PROC_TID_ATTR,       "attr",    S_IFDIR|S_IRUGO|S_IXUGO),
241 #endif
242 #ifdef CONFIG_KALLSYMS
243 	E(PROC_TID_WCHAN,      "wchan",   S_IFREG|S_IRUGO),
244 #endif
245 #ifdef CONFIG_SCHEDSTATS
246 	E(PROC_TID_SCHEDSTAT, "schedstat",S_IFREG|S_IRUGO),
247 #endif
248 #ifdef CONFIG_CPUSETS
249 	E(PROC_TID_CPUSET,     "cpuset",  S_IFREG|S_IRUGO),
250 #endif
251 	E(PROC_TID_OOM_SCORE,  "oom_score",S_IFREG|S_IRUGO),
252 	E(PROC_TID_OOM_ADJUST, "oom_adj", S_IFREG|S_IRUGO|S_IWUSR),
253 #ifdef CONFIG_AUDITSYSCALL
254 	E(PROC_TID_LOGINUID, "loginuid", S_IFREG|S_IWUSR|S_IRUGO),
255 #endif
256 	{0,0,NULL,0}
257 };
258 
259 #ifdef CONFIG_SECURITY
260 static struct pid_entry tgid_attr_stuff[] = {
261 	E(PROC_TGID_ATTR_CURRENT,  "current",  S_IFREG|S_IRUGO|S_IWUGO),
262 	E(PROC_TGID_ATTR_PREV,     "prev",     S_IFREG|S_IRUGO),
263 	E(PROC_TGID_ATTR_EXEC,     "exec",     S_IFREG|S_IRUGO|S_IWUGO),
264 	E(PROC_TGID_ATTR_FSCREATE, "fscreate", S_IFREG|S_IRUGO|S_IWUGO),
265 	{0,0,NULL,0}
266 };
267 static struct pid_entry tid_attr_stuff[] = {
268 	E(PROC_TID_ATTR_CURRENT,   "current",  S_IFREG|S_IRUGO|S_IWUGO),
269 	E(PROC_TID_ATTR_PREV,      "prev",     S_IFREG|S_IRUGO),
270 	E(PROC_TID_ATTR_EXEC,      "exec",     S_IFREG|S_IRUGO|S_IWUGO),
271 	E(PROC_TID_ATTR_FSCREATE,  "fscreate", S_IFREG|S_IRUGO|S_IWUGO),
272 	{0,0,NULL,0}
273 };
274 #endif
275 
276 #undef E
277 
278 static int proc_fd_link(struct inode *inode, struct dentry **dentry, struct vfsmount **mnt)
279 {
280 	struct task_struct *task = proc_task(inode);
281 	struct files_struct *files;
282 	struct file *file;
283 	int fd = proc_type(inode) - PROC_TID_FD_DIR;
284 
285 	files = get_files_struct(task);
286 	if (files) {
287 		rcu_read_lock();
288 		file = fcheck_files(files, fd);
289 		if (file) {
290 			*mnt = mntget(file->f_vfsmnt);
291 			*dentry = dget(file->f_dentry);
292 			rcu_read_unlock();
293 			put_files_struct(files);
294 			return 0;
295 		}
296 		rcu_read_unlock();
297 		put_files_struct(files);
298 	}
299 	return -ENOENT;
300 }
301 
302 static struct fs_struct *get_fs_struct(struct task_struct *task)
303 {
304 	struct fs_struct *fs;
305 	task_lock(task);
306 	fs = task->fs;
307 	if(fs)
308 		atomic_inc(&fs->count);
309 	task_unlock(task);
310 	return fs;
311 }
312 
313 static int proc_cwd_link(struct inode *inode, struct dentry **dentry, struct vfsmount **mnt)
314 {
315 	struct fs_struct *fs = get_fs_struct(proc_task(inode));
316 	int result = -ENOENT;
317 	if (fs) {
318 		read_lock(&fs->lock);
319 		*mnt = mntget(fs->pwdmnt);
320 		*dentry = dget(fs->pwd);
321 		read_unlock(&fs->lock);
322 		result = 0;
323 		put_fs_struct(fs);
324 	}
325 	return result;
326 }
327 
328 static int proc_root_link(struct inode *inode, struct dentry **dentry, struct vfsmount **mnt)
329 {
330 	struct fs_struct *fs = get_fs_struct(proc_task(inode));
331 	int result = -ENOENT;
332 	if (fs) {
333 		read_lock(&fs->lock);
334 		*mnt = mntget(fs->rootmnt);
335 		*dentry = dget(fs->root);
336 		read_unlock(&fs->lock);
337 		result = 0;
338 		put_fs_struct(fs);
339 	}
340 	return result;
341 }
342 
343 
344 /* Same as proc_root_link, but this addionally tries to get fs from other
345  * threads in the group */
346 static int proc_task_root_link(struct inode *inode, struct dentry **dentry,
347 				struct vfsmount **mnt)
348 {
349 	struct fs_struct *fs;
350 	int result = -ENOENT;
351 	struct task_struct *leader = proc_task(inode);
352 
353 	task_lock(leader);
354 	fs = leader->fs;
355 	if (fs) {
356 		atomic_inc(&fs->count);
357 		task_unlock(leader);
358 	} else {
359 		/* Try to get fs from other threads */
360 		task_unlock(leader);
361 		read_lock(&tasklist_lock);
362 		if (pid_alive(leader)) {
363 			struct task_struct *task = leader;
364 
365 			while ((task = next_thread(task)) != leader) {
366 				task_lock(task);
367 				fs = task->fs;
368 				if (fs) {
369 					atomic_inc(&fs->count);
370 					task_unlock(task);
371 					break;
372 				}
373 				task_unlock(task);
374 			}
375 		}
376 		read_unlock(&tasklist_lock);
377 	}
378 
379 	if (fs) {
380 		read_lock(&fs->lock);
381 		*mnt = mntget(fs->rootmnt);
382 		*dentry = dget(fs->root);
383 		read_unlock(&fs->lock);
384 		result = 0;
385 		put_fs_struct(fs);
386 	}
387 	return result;
388 }
389 
390 
391 #define MAY_PTRACE(task) \
392 	(task == current || \
393 	(task->parent == current && \
394 	(task->ptrace & PT_PTRACED) && \
395 	 (task->state == TASK_STOPPED || task->state == TASK_TRACED) && \
396 	 security_ptrace(current,task) == 0))
397 
398 static int proc_pid_environ(struct task_struct *task, char * buffer)
399 {
400 	int res = 0;
401 	struct mm_struct *mm = get_task_mm(task);
402 	if (mm) {
403 		unsigned int len = mm->env_end - mm->env_start;
404 		if (len > PAGE_SIZE)
405 			len = PAGE_SIZE;
406 		res = access_process_vm(task, mm->env_start, buffer, len, 0);
407 		if (!ptrace_may_attach(task))
408 			res = -ESRCH;
409 		mmput(mm);
410 	}
411 	return res;
412 }
413 
414 static int proc_pid_cmdline(struct task_struct *task, char * buffer)
415 {
416 	int res = 0;
417 	unsigned int len;
418 	struct mm_struct *mm = get_task_mm(task);
419 	if (!mm)
420 		goto out;
421 	if (!mm->arg_end)
422 		goto out_mm;	/* Shh! No looking before we're done */
423 
424  	len = mm->arg_end - mm->arg_start;
425 
426 	if (len > PAGE_SIZE)
427 		len = PAGE_SIZE;
428 
429 	res = access_process_vm(task, mm->arg_start, buffer, len, 0);
430 
431 	// If the nul at the end of args has been overwritten, then
432 	// assume application is using setproctitle(3).
433 	if (res > 0 && buffer[res-1] != '\0' && len < PAGE_SIZE) {
434 		len = strnlen(buffer, res);
435 		if (len < res) {
436 		    res = len;
437 		} else {
438 			len = mm->env_end - mm->env_start;
439 			if (len > PAGE_SIZE - res)
440 				len = PAGE_SIZE - res;
441 			res += access_process_vm(task, mm->env_start, buffer+res, len, 0);
442 			res = strnlen(buffer, res);
443 		}
444 	}
445 out_mm:
446 	mmput(mm);
447 out:
448 	return res;
449 }
450 
451 static int proc_pid_auxv(struct task_struct *task, char *buffer)
452 {
453 	int res = 0;
454 	struct mm_struct *mm = get_task_mm(task);
455 	if (mm) {
456 		unsigned int nwords = 0;
457 		do
458 			nwords += 2;
459 		while (mm->saved_auxv[nwords - 2] != 0); /* AT_NULL */
460 		res = nwords * sizeof(mm->saved_auxv[0]);
461 		if (res > PAGE_SIZE)
462 			res = PAGE_SIZE;
463 		memcpy(buffer, mm->saved_auxv, res);
464 		mmput(mm);
465 	}
466 	return res;
467 }
468 
469 
470 #ifdef CONFIG_KALLSYMS
471 /*
472  * Provides a wchan file via kallsyms in a proper one-value-per-file format.
473  * Returns the resolved symbol.  If that fails, simply return the address.
474  */
475 static int proc_pid_wchan(struct task_struct *task, char *buffer)
476 {
477 	char *modname;
478 	const char *sym_name;
479 	unsigned long wchan, size, offset;
480 	char namebuf[KSYM_NAME_LEN+1];
481 
482 	wchan = get_wchan(task);
483 
484 	sym_name = kallsyms_lookup(wchan, &size, &offset, &modname, namebuf);
485 	if (sym_name)
486 		return sprintf(buffer, "%s", sym_name);
487 	return sprintf(buffer, "%lu", wchan);
488 }
489 #endif /* CONFIG_KALLSYMS */
490 
491 #ifdef CONFIG_SCHEDSTATS
492 /*
493  * Provides /proc/PID/schedstat
494  */
495 static int proc_pid_schedstat(struct task_struct *task, char *buffer)
496 {
497 	return sprintf(buffer, "%lu %lu %lu\n",
498 			task->sched_info.cpu_time,
499 			task->sched_info.run_delay,
500 			task->sched_info.pcnt);
501 }
502 #endif
503 
504 /* The badness from the OOM killer */
505 unsigned long badness(struct task_struct *p, unsigned long uptime);
506 static int proc_oom_score(struct task_struct *task, char *buffer)
507 {
508 	unsigned long points;
509 	struct timespec uptime;
510 
511 	do_posix_clock_monotonic_gettime(&uptime);
512 	points = badness(task, uptime.tv_sec);
513 	return sprintf(buffer, "%lu\n", points);
514 }
515 
516 /************************************************************************/
517 /*                       Here the fs part begins                        */
518 /************************************************************************/
519 
520 /* permission checks */
521 
522 /* If the process being read is separated by chroot from the reading process,
523  * don't let the reader access the threads.
524  */
525 static int proc_check_chroot(struct dentry *root, struct vfsmount *vfsmnt)
526 {
527 	struct dentry *de, *base;
528 	struct vfsmount *our_vfsmnt, *mnt;
529 	int res = 0;
530 	read_lock(&current->fs->lock);
531 	our_vfsmnt = mntget(current->fs->rootmnt);
532 	base = dget(current->fs->root);
533 	read_unlock(&current->fs->lock);
534 
535 	spin_lock(&vfsmount_lock);
536 	de = root;
537 	mnt = vfsmnt;
538 
539 	while (vfsmnt != our_vfsmnt) {
540 		if (vfsmnt == vfsmnt->mnt_parent)
541 			goto out;
542 		de = vfsmnt->mnt_mountpoint;
543 		vfsmnt = vfsmnt->mnt_parent;
544 	}
545 
546 	if (!is_subdir(de, base))
547 		goto out;
548 	spin_unlock(&vfsmount_lock);
549 
550 exit:
551 	dput(base);
552 	mntput(our_vfsmnt);
553 	dput(root);
554 	mntput(mnt);
555 	return res;
556 out:
557 	spin_unlock(&vfsmount_lock);
558 	res = -EACCES;
559 	goto exit;
560 }
561 
562 static int proc_check_root(struct inode *inode)
563 {
564 	struct dentry *root;
565 	struct vfsmount *vfsmnt;
566 
567 	if (proc_root_link(inode, &root, &vfsmnt)) /* Ewww... */
568 		return -ENOENT;
569 	return proc_check_chroot(root, vfsmnt);
570 }
571 
572 static int proc_permission(struct inode *inode, int mask, struct nameidata *nd)
573 {
574 	if (generic_permission(inode, mask, NULL) != 0)
575 		return -EACCES;
576 	return proc_check_root(inode);
577 }
578 
579 static int proc_task_permission(struct inode *inode, int mask, struct nameidata *nd)
580 {
581 	struct dentry *root;
582 	struct vfsmount *vfsmnt;
583 
584 	if (generic_permission(inode, mask, NULL) != 0)
585 		return -EACCES;
586 
587 	if (proc_task_root_link(inode, &root, &vfsmnt))
588 		return -ENOENT;
589 
590 	return proc_check_chroot(root, vfsmnt);
591 }
592 
593 extern struct seq_operations proc_pid_maps_op;
594 static int maps_open(struct inode *inode, struct file *file)
595 {
596 	struct task_struct *task = proc_task(inode);
597 	int ret = seq_open(file, &proc_pid_maps_op);
598 	if (!ret) {
599 		struct seq_file *m = file->private_data;
600 		m->private = task;
601 	}
602 	return ret;
603 }
604 
605 static struct file_operations proc_maps_operations = {
606 	.open		= maps_open,
607 	.read		= seq_read,
608 	.llseek		= seq_lseek,
609 	.release	= seq_release,
610 };
611 
612 #ifdef CONFIG_NUMA
613 extern struct seq_operations proc_pid_numa_maps_op;
614 static int numa_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_numa_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_numa_maps_operations = {
626 	.open		= numa_maps_open,
627 	.read		= seq_read,
628 	.llseek		= seq_lseek,
629 	.release	= seq_release,
630 };
631 #endif
632 
633 extern struct seq_operations proc_pid_smaps_op;
634 static int smaps_open(struct inode *inode, struct file *file)
635 {
636 	struct task_struct *task = proc_task(inode);
637 	int ret = seq_open(file, &proc_pid_smaps_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_smaps_operations = {
646 	.open		= smaps_open,
647 	.read		= seq_read,
648 	.llseek		= seq_lseek,
649 	.release	= seq_release,
650 };
651 
652 extern struct seq_operations mounts_op;
653 static int mounts_open(struct inode *inode, struct file *file)
654 {
655 	struct task_struct *task = proc_task(inode);
656 	int ret = seq_open(file, &mounts_op);
657 
658 	if (!ret) {
659 		struct seq_file *m = file->private_data;
660 		struct namespace *namespace;
661 		task_lock(task);
662 		namespace = task->namespace;
663 		if (namespace)
664 			get_namespace(namespace);
665 		task_unlock(task);
666 
667 		if (namespace)
668 			m->private = namespace;
669 		else {
670 			seq_release(inode, file);
671 			ret = -EINVAL;
672 		}
673 	}
674 	return ret;
675 }
676 
677 static int mounts_release(struct inode *inode, struct file *file)
678 {
679 	struct seq_file *m = file->private_data;
680 	struct namespace *namespace = m->private;
681 	put_namespace(namespace);
682 	return seq_release(inode, file);
683 }
684 
685 static struct file_operations proc_mounts_operations = {
686 	.open		= mounts_open,
687 	.read		= seq_read,
688 	.llseek		= seq_lseek,
689 	.release	= mounts_release,
690 };
691 
692 #define PROC_BLOCK_SIZE	(3*1024)		/* 4K page size but our output routines use some slack for overruns */
693 
694 static ssize_t proc_info_read(struct file * file, char __user * buf,
695 			  size_t count, loff_t *ppos)
696 {
697 	struct inode * inode = file->f_dentry->d_inode;
698 	unsigned long page;
699 	ssize_t length;
700 	struct task_struct *task = proc_task(inode);
701 
702 	if (count > PROC_BLOCK_SIZE)
703 		count = PROC_BLOCK_SIZE;
704 	if (!(page = __get_free_page(GFP_KERNEL)))
705 		return -ENOMEM;
706 
707 	length = PROC_I(inode)->op.proc_read(task, (char*)page);
708 
709 	if (length >= 0)
710 		length = simple_read_from_buffer(buf, count, ppos, (char *)page, length);
711 	free_page(page);
712 	return length;
713 }
714 
715 static struct file_operations proc_info_file_operations = {
716 	.read		= proc_info_read,
717 };
718 
719 static int mem_open(struct inode* inode, struct file* file)
720 {
721 	file->private_data = (void*)((long)current->self_exec_id);
722 	return 0;
723 }
724 
725 static ssize_t mem_read(struct file * file, char __user * buf,
726 			size_t count, loff_t *ppos)
727 {
728 	struct task_struct *task = proc_task(file->f_dentry->d_inode);
729 	char *page;
730 	unsigned long src = *ppos;
731 	int ret = -ESRCH;
732 	struct mm_struct *mm;
733 
734 	if (!MAY_PTRACE(task) || !ptrace_may_attach(task))
735 		goto out;
736 
737 	ret = -ENOMEM;
738 	page = (char *)__get_free_page(GFP_USER);
739 	if (!page)
740 		goto out;
741 
742 	ret = 0;
743 
744 	mm = get_task_mm(task);
745 	if (!mm)
746 		goto out_free;
747 
748 	ret = -EIO;
749 
750 	if (file->private_data != (void*)((long)current->self_exec_id))
751 		goto out_put;
752 
753 	ret = 0;
754 
755 	while (count > 0) {
756 		int this_len, retval;
757 
758 		this_len = (count > PAGE_SIZE) ? PAGE_SIZE : count;
759 		retval = access_process_vm(task, src, page, this_len, 0);
760 		if (!retval || !MAY_PTRACE(task) || !ptrace_may_attach(task)) {
761 			if (!ret)
762 				ret = -EIO;
763 			break;
764 		}
765 
766 		if (copy_to_user(buf, page, retval)) {
767 			ret = -EFAULT;
768 			break;
769 		}
770 
771 		ret += retval;
772 		src += retval;
773 		buf += retval;
774 		count -= retval;
775 	}
776 	*ppos = src;
777 
778 out_put:
779 	mmput(mm);
780 out_free:
781 	free_page((unsigned long) page);
782 out:
783 	return ret;
784 }
785 
786 #define mem_write NULL
787 
788 #ifndef mem_write
789 /* This is a security hazard */
790 static ssize_t mem_write(struct file * file, const char * buf,
791 			 size_t count, loff_t *ppos)
792 {
793 	int copied = 0;
794 	char *page;
795 	struct task_struct *task = proc_task(file->f_dentry->d_inode);
796 	unsigned long dst = *ppos;
797 
798 	if (!MAY_PTRACE(task) || !ptrace_may_attach(task))
799 		return -ESRCH;
800 
801 	page = (char *)__get_free_page(GFP_USER);
802 	if (!page)
803 		return -ENOMEM;
804 
805 	while (count > 0) {
806 		int this_len, retval;
807 
808 		this_len = (count > PAGE_SIZE) ? PAGE_SIZE : count;
809 		if (copy_from_user(page, buf, this_len)) {
810 			copied = -EFAULT;
811 			break;
812 		}
813 		retval = access_process_vm(task, dst, page, this_len, 1);
814 		if (!retval) {
815 			if (!copied)
816 				copied = -EIO;
817 			break;
818 		}
819 		copied += retval;
820 		buf += retval;
821 		dst += retval;
822 		count -= retval;
823 	}
824 	*ppos = dst;
825 	free_page((unsigned long) page);
826 	return copied;
827 }
828 #endif
829 
830 static loff_t mem_lseek(struct file * file, loff_t offset, int orig)
831 {
832 	switch (orig) {
833 	case 0:
834 		file->f_pos = offset;
835 		break;
836 	case 1:
837 		file->f_pos += offset;
838 		break;
839 	default:
840 		return -EINVAL;
841 	}
842 	force_successful_syscall_return();
843 	return file->f_pos;
844 }
845 
846 static struct file_operations proc_mem_operations = {
847 	.llseek		= mem_lseek,
848 	.read		= mem_read,
849 	.write		= mem_write,
850 	.open		= mem_open,
851 };
852 
853 static ssize_t oom_adjust_read(struct file *file, char __user *buf,
854 				size_t count, loff_t *ppos)
855 {
856 	struct task_struct *task = proc_task(file->f_dentry->d_inode);
857 	char buffer[8];
858 	size_t len;
859 	int oom_adjust = task->oomkilladj;
860 	loff_t __ppos = *ppos;
861 
862 	len = sprintf(buffer, "%i\n", oom_adjust);
863 	if (__ppos >= len)
864 		return 0;
865 	if (count > len-__ppos)
866 		count = len-__ppos;
867 	if (copy_to_user(buf, buffer + __ppos, count))
868 		return -EFAULT;
869 	*ppos = __ppos + count;
870 	return count;
871 }
872 
873 static ssize_t oom_adjust_write(struct file *file, const char __user *buf,
874 				size_t count, loff_t *ppos)
875 {
876 	struct task_struct *task = proc_task(file->f_dentry->d_inode);
877 	char buffer[8], *end;
878 	int oom_adjust;
879 
880 	if (!capable(CAP_SYS_RESOURCE))
881 		return -EPERM;
882 	memset(buffer, 0, 8);
883 	if (count > 6)
884 		count = 6;
885 	if (copy_from_user(buffer, buf, count))
886 		return -EFAULT;
887 	oom_adjust = simple_strtol(buffer, &end, 0);
888 	if ((oom_adjust < -16 || oom_adjust > 15) && oom_adjust != OOM_DISABLE)
889 		return -EINVAL;
890 	if (*end == '\n')
891 		end++;
892 	task->oomkilladj = oom_adjust;
893 	if (end - buffer == 0)
894 		return -EIO;
895 	return end - buffer;
896 }
897 
898 static struct file_operations proc_oom_adjust_operations = {
899 	.read		= oom_adjust_read,
900 	.write		= oom_adjust_write,
901 };
902 
903 static struct inode_operations proc_mem_inode_operations = {
904 	.permission	= proc_permission,
905 };
906 
907 #ifdef CONFIG_AUDITSYSCALL
908 #define TMPBUFLEN 21
909 static ssize_t proc_loginuid_read(struct file * file, char __user * buf,
910 				  size_t count, loff_t *ppos)
911 {
912 	struct inode * inode = file->f_dentry->d_inode;
913 	struct task_struct *task = proc_task(inode);
914 	ssize_t length;
915 	char tmpbuf[TMPBUFLEN];
916 
917 	length = scnprintf(tmpbuf, TMPBUFLEN, "%u",
918 				audit_get_loginuid(task->audit_context));
919 	return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
920 }
921 
922 static ssize_t proc_loginuid_write(struct file * file, const char __user * buf,
923 				   size_t count, loff_t *ppos)
924 {
925 	struct inode * inode = file->f_dentry->d_inode;
926 	char *page, *tmp;
927 	ssize_t length;
928 	struct task_struct *task = proc_task(inode);
929 	uid_t loginuid;
930 
931 	if (!capable(CAP_AUDIT_CONTROL))
932 		return -EPERM;
933 
934 	if (current != task)
935 		return -EPERM;
936 
937 	if (count > PAGE_SIZE)
938 		count = PAGE_SIZE;
939 
940 	if (*ppos != 0) {
941 		/* No partial writes. */
942 		return -EINVAL;
943 	}
944 	page = (char*)__get_free_page(GFP_USER);
945 	if (!page)
946 		return -ENOMEM;
947 	length = -EFAULT;
948 	if (copy_from_user(page, buf, count))
949 		goto out_free_page;
950 
951 	loginuid = simple_strtoul(page, &tmp, 10);
952 	if (tmp == page) {
953 		length = -EINVAL;
954 		goto out_free_page;
955 
956 	}
957 	length = audit_set_loginuid(task, loginuid);
958 	if (likely(length == 0))
959 		length = count;
960 
961 out_free_page:
962 	free_page((unsigned long) page);
963 	return length;
964 }
965 
966 static struct file_operations proc_loginuid_operations = {
967 	.read		= proc_loginuid_read,
968 	.write		= proc_loginuid_write,
969 };
970 #endif
971 
972 #ifdef CONFIG_SECCOMP
973 static ssize_t seccomp_read(struct file *file, char __user *buf,
974 			    size_t count, loff_t *ppos)
975 {
976 	struct task_struct *tsk = proc_task(file->f_dentry->d_inode);
977 	char __buf[20];
978 	loff_t __ppos = *ppos;
979 	size_t len;
980 
981 	/* no need to print the trailing zero, so use only len */
982 	len = sprintf(__buf, "%u\n", tsk->seccomp.mode);
983 	if (__ppos >= len)
984 		return 0;
985 	if (count > len - __ppos)
986 		count = len - __ppos;
987 	if (copy_to_user(buf, __buf + __ppos, count))
988 		return -EFAULT;
989 	*ppos = __ppos + count;
990 	return count;
991 }
992 
993 static ssize_t seccomp_write(struct file *file, const char __user *buf,
994 			     size_t count, loff_t *ppos)
995 {
996 	struct task_struct *tsk = proc_task(file->f_dentry->d_inode);
997 	char __buf[20], *end;
998 	unsigned int seccomp_mode;
999 
1000 	/* can set it only once to be even more secure */
1001 	if (unlikely(tsk->seccomp.mode))
1002 		return -EPERM;
1003 
1004 	memset(__buf, 0, sizeof(__buf));
1005 	count = min(count, sizeof(__buf) - 1);
1006 	if (copy_from_user(__buf, buf, count))
1007 		return -EFAULT;
1008 	seccomp_mode = simple_strtoul(__buf, &end, 0);
1009 	if (*end == '\n')
1010 		end++;
1011 	if (seccomp_mode && seccomp_mode <= NR_SECCOMP_MODES) {
1012 		tsk->seccomp.mode = seccomp_mode;
1013 		set_tsk_thread_flag(tsk, TIF_SECCOMP);
1014 	} else
1015 		return -EINVAL;
1016 	if (unlikely(!(end - __buf)))
1017 		return -EIO;
1018 	return end - __buf;
1019 }
1020 
1021 static struct file_operations proc_seccomp_operations = {
1022 	.read		= seccomp_read,
1023 	.write		= seccomp_write,
1024 };
1025 #endif /* CONFIG_SECCOMP */
1026 
1027 static void *proc_pid_follow_link(struct dentry *dentry, struct nameidata *nd)
1028 {
1029 	struct inode *inode = dentry->d_inode;
1030 	int error = -EACCES;
1031 
1032 	/* We don't need a base pointer in the /proc filesystem */
1033 	path_release(nd);
1034 
1035 	if (current->fsuid != inode->i_uid && !capable(CAP_DAC_OVERRIDE))
1036 		goto out;
1037 	error = proc_check_root(inode);
1038 	if (error)
1039 		goto out;
1040 
1041 	error = PROC_I(inode)->op.proc_get_link(inode, &nd->dentry, &nd->mnt);
1042 	nd->last_type = LAST_BIND;
1043 out:
1044 	return ERR_PTR(error);
1045 }
1046 
1047 static int do_proc_readlink(struct dentry *dentry, struct vfsmount *mnt,
1048 			    char __user *buffer, int buflen)
1049 {
1050 	struct inode * inode;
1051 	char *tmp = (char*)__get_free_page(GFP_KERNEL), *path;
1052 	int len;
1053 
1054 	if (!tmp)
1055 		return -ENOMEM;
1056 
1057 	inode = dentry->d_inode;
1058 	path = d_path(dentry, mnt, tmp, PAGE_SIZE);
1059 	len = PTR_ERR(path);
1060 	if (IS_ERR(path))
1061 		goto out;
1062 	len = tmp + PAGE_SIZE - 1 - path;
1063 
1064 	if (len > buflen)
1065 		len = buflen;
1066 	if (copy_to_user(buffer, path, len))
1067 		len = -EFAULT;
1068  out:
1069 	free_page((unsigned long)tmp);
1070 	return len;
1071 }
1072 
1073 static int proc_pid_readlink(struct dentry * dentry, char __user * buffer, int buflen)
1074 {
1075 	int error = -EACCES;
1076 	struct inode *inode = dentry->d_inode;
1077 	struct dentry *de;
1078 	struct vfsmount *mnt = NULL;
1079 
1080 	lock_kernel();
1081 
1082 	if (current->fsuid != inode->i_uid && !capable(CAP_DAC_OVERRIDE))
1083 		goto out;
1084 	error = proc_check_root(inode);
1085 	if (error)
1086 		goto out;
1087 
1088 	error = PROC_I(inode)->op.proc_get_link(inode, &de, &mnt);
1089 	if (error)
1090 		goto out;
1091 
1092 	error = do_proc_readlink(de, mnt, buffer, buflen);
1093 	dput(de);
1094 	mntput(mnt);
1095 out:
1096 	unlock_kernel();
1097 	return error;
1098 }
1099 
1100 static struct inode_operations proc_pid_link_inode_operations = {
1101 	.readlink	= proc_pid_readlink,
1102 	.follow_link	= proc_pid_follow_link
1103 };
1104 
1105 #define NUMBUF 10
1106 
1107 static int proc_readfd(struct file * filp, void * dirent, filldir_t filldir)
1108 {
1109 	struct inode *inode = filp->f_dentry->d_inode;
1110 	struct task_struct *p = proc_task(inode);
1111 	unsigned int fd, tid, ino;
1112 	int retval;
1113 	char buf[NUMBUF];
1114 	struct files_struct * files;
1115 	struct fdtable *fdt;
1116 
1117 	retval = -ENOENT;
1118 	if (!pid_alive(p))
1119 		goto out;
1120 	retval = 0;
1121 	tid = p->pid;
1122 
1123 	fd = filp->f_pos;
1124 	switch (fd) {
1125 		case 0:
1126 			if (filldir(dirent, ".", 1, 0, inode->i_ino, DT_DIR) < 0)
1127 				goto out;
1128 			filp->f_pos++;
1129 		case 1:
1130 			ino = fake_ino(tid, PROC_TID_INO);
1131 			if (filldir(dirent, "..", 2, 1, ino, DT_DIR) < 0)
1132 				goto out;
1133 			filp->f_pos++;
1134 		default:
1135 			files = get_files_struct(p);
1136 			if (!files)
1137 				goto out;
1138 			rcu_read_lock();
1139 			fdt = files_fdtable(files);
1140 			for (fd = filp->f_pos-2;
1141 			     fd < fdt->max_fds;
1142 			     fd++, filp->f_pos++) {
1143 				unsigned int i,j;
1144 
1145 				if (!fcheck_files(files, fd))
1146 					continue;
1147 				rcu_read_unlock();
1148 
1149 				j = NUMBUF;
1150 				i = fd;
1151 				do {
1152 					j--;
1153 					buf[j] = '0' + (i % 10);
1154 					i /= 10;
1155 				} while (i);
1156 
1157 				ino = fake_ino(tid, PROC_TID_FD_DIR + fd);
1158 				if (filldir(dirent, buf+j, NUMBUF-j, fd+2, ino, DT_LNK) < 0) {
1159 					rcu_read_lock();
1160 					break;
1161 				}
1162 				rcu_read_lock();
1163 			}
1164 			rcu_read_unlock();
1165 			put_files_struct(files);
1166 	}
1167 out:
1168 	return retval;
1169 }
1170 
1171 static int proc_pident_readdir(struct file *filp,
1172 		void *dirent, filldir_t filldir,
1173 		struct pid_entry *ents, unsigned int nents)
1174 {
1175 	int i;
1176 	int pid;
1177 	struct dentry *dentry = filp->f_dentry;
1178 	struct inode *inode = dentry->d_inode;
1179 	struct pid_entry *p;
1180 	ino_t ino;
1181 	int ret;
1182 
1183 	ret = -ENOENT;
1184 	if (!pid_alive(proc_task(inode)))
1185 		goto out;
1186 
1187 	ret = 0;
1188 	pid = proc_task(inode)->pid;
1189 	i = filp->f_pos;
1190 	switch (i) {
1191 	case 0:
1192 		ino = inode->i_ino;
1193 		if (filldir(dirent, ".", 1, i, ino, DT_DIR) < 0)
1194 			goto out;
1195 		i++;
1196 		filp->f_pos++;
1197 		/* fall through */
1198 	case 1:
1199 		ino = parent_ino(dentry);
1200 		if (filldir(dirent, "..", 2, i, ino, DT_DIR) < 0)
1201 			goto out;
1202 		i++;
1203 		filp->f_pos++;
1204 		/* fall through */
1205 	default:
1206 		i -= 2;
1207 		if (i >= nents) {
1208 			ret = 1;
1209 			goto out;
1210 		}
1211 		p = ents + i;
1212 		while (p->name) {
1213 			if (filldir(dirent, p->name, p->len, filp->f_pos,
1214 				    fake_ino(pid, p->type), p->mode >> 12) < 0)
1215 				goto out;
1216 			filp->f_pos++;
1217 			p++;
1218 		}
1219 	}
1220 
1221 	ret = 1;
1222 out:
1223 	return ret;
1224 }
1225 
1226 static int proc_tgid_base_readdir(struct file * filp,
1227 			     void * dirent, filldir_t filldir)
1228 {
1229 	return proc_pident_readdir(filp,dirent,filldir,
1230 				   tgid_base_stuff,ARRAY_SIZE(tgid_base_stuff));
1231 }
1232 
1233 static int proc_tid_base_readdir(struct file * filp,
1234 			     void * dirent, filldir_t filldir)
1235 {
1236 	return proc_pident_readdir(filp,dirent,filldir,
1237 				   tid_base_stuff,ARRAY_SIZE(tid_base_stuff));
1238 }
1239 
1240 /* building an inode */
1241 
1242 static int task_dumpable(struct task_struct *task)
1243 {
1244 	int dumpable = 0;
1245 	struct mm_struct *mm;
1246 
1247 	task_lock(task);
1248 	mm = task->mm;
1249 	if (mm)
1250 		dumpable = mm->dumpable;
1251 	task_unlock(task);
1252 	if(dumpable == 1)
1253 		return 1;
1254 	return 0;
1255 }
1256 
1257 
1258 static struct inode *proc_pid_make_inode(struct super_block * sb, struct task_struct *task, int ino)
1259 {
1260 	struct inode * inode;
1261 	struct proc_inode *ei;
1262 
1263 	/* We need a new inode */
1264 
1265 	inode = new_inode(sb);
1266 	if (!inode)
1267 		goto out;
1268 
1269 	/* Common stuff */
1270 	ei = PROC_I(inode);
1271 	ei->task = NULL;
1272 	inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
1273 	inode->i_ino = fake_ino(task->pid, ino);
1274 
1275 	if (!pid_alive(task))
1276 		goto out_unlock;
1277 
1278 	/*
1279 	 * grab the reference to task.
1280 	 */
1281 	get_task_struct(task);
1282 	ei->task = task;
1283 	ei->type = ino;
1284 	inode->i_uid = 0;
1285 	inode->i_gid = 0;
1286 	if (ino == PROC_TGID_INO || ino == PROC_TID_INO || task_dumpable(task)) {
1287 		inode->i_uid = task->euid;
1288 		inode->i_gid = task->egid;
1289 	}
1290 	security_task_to_inode(task, inode);
1291 
1292 out:
1293 	return inode;
1294 
1295 out_unlock:
1296 	ei->pde = NULL;
1297 	iput(inode);
1298 	return NULL;
1299 }
1300 
1301 /* dentry stuff */
1302 
1303 /*
1304  *	Exceptional case: normally we are not allowed to unhash a busy
1305  * directory. In this case, however, we can do it - no aliasing problems
1306  * due to the way we treat inodes.
1307  *
1308  * Rewrite the inode's ownerships here because the owning task may have
1309  * performed a setuid(), etc.
1310  */
1311 static int pid_revalidate(struct dentry *dentry, struct nameidata *nd)
1312 {
1313 	struct inode *inode = dentry->d_inode;
1314 	struct task_struct *task = proc_task(inode);
1315 	if (pid_alive(task)) {
1316 		if (proc_type(inode) == PROC_TGID_INO || proc_type(inode) == PROC_TID_INO || task_dumpable(task)) {
1317 			inode->i_uid = task->euid;
1318 			inode->i_gid = task->egid;
1319 		} else {
1320 			inode->i_uid = 0;
1321 			inode->i_gid = 0;
1322 		}
1323 		security_task_to_inode(task, inode);
1324 		return 1;
1325 	}
1326 	d_drop(dentry);
1327 	return 0;
1328 }
1329 
1330 static int tid_fd_revalidate(struct dentry *dentry, struct nameidata *nd)
1331 {
1332 	struct inode *inode = dentry->d_inode;
1333 	struct task_struct *task = proc_task(inode);
1334 	int fd = proc_type(inode) - PROC_TID_FD_DIR;
1335 	struct files_struct *files;
1336 
1337 	files = get_files_struct(task);
1338 	if (files) {
1339 		rcu_read_lock();
1340 		if (fcheck_files(files, fd)) {
1341 			rcu_read_unlock();
1342 			put_files_struct(files);
1343 			if (task_dumpable(task)) {
1344 				inode->i_uid = task->euid;
1345 				inode->i_gid = task->egid;
1346 			} else {
1347 				inode->i_uid = 0;
1348 				inode->i_gid = 0;
1349 			}
1350 			security_task_to_inode(task, inode);
1351 			return 1;
1352 		}
1353 		rcu_read_unlock();
1354 		put_files_struct(files);
1355 	}
1356 	d_drop(dentry);
1357 	return 0;
1358 }
1359 
1360 static void pid_base_iput(struct dentry *dentry, struct inode *inode)
1361 {
1362 	struct task_struct *task = proc_task(inode);
1363 	spin_lock(&task->proc_lock);
1364 	if (task->proc_dentry == dentry)
1365 		task->proc_dentry = NULL;
1366 	spin_unlock(&task->proc_lock);
1367 	iput(inode);
1368 }
1369 
1370 static int pid_delete_dentry(struct dentry * dentry)
1371 {
1372 	/* Is the task we represent dead?
1373 	 * If so, then don't put the dentry on the lru list,
1374 	 * kill it immediately.
1375 	 */
1376 	return !pid_alive(proc_task(dentry->d_inode));
1377 }
1378 
1379 static struct dentry_operations tid_fd_dentry_operations =
1380 {
1381 	.d_revalidate	= tid_fd_revalidate,
1382 	.d_delete	= pid_delete_dentry,
1383 };
1384 
1385 static struct dentry_operations pid_dentry_operations =
1386 {
1387 	.d_revalidate	= pid_revalidate,
1388 	.d_delete	= pid_delete_dentry,
1389 };
1390 
1391 static struct dentry_operations pid_base_dentry_operations =
1392 {
1393 	.d_revalidate	= pid_revalidate,
1394 	.d_iput		= pid_base_iput,
1395 	.d_delete	= pid_delete_dentry,
1396 };
1397 
1398 /* Lookups */
1399 
1400 static unsigned name_to_int(struct dentry *dentry)
1401 {
1402 	const char *name = dentry->d_name.name;
1403 	int len = dentry->d_name.len;
1404 	unsigned n = 0;
1405 
1406 	if (len > 1 && *name == '0')
1407 		goto out;
1408 	while (len-- > 0) {
1409 		unsigned c = *name++ - '0';
1410 		if (c > 9)
1411 			goto out;
1412 		if (n >= (~0U-9)/10)
1413 			goto out;
1414 		n *= 10;
1415 		n += c;
1416 	}
1417 	return n;
1418 out:
1419 	return ~0U;
1420 }
1421 
1422 /* SMP-safe */
1423 static struct dentry *proc_lookupfd(struct inode * dir, struct dentry * dentry, struct nameidata *nd)
1424 {
1425 	struct task_struct *task = proc_task(dir);
1426 	unsigned fd = name_to_int(dentry);
1427 	struct file * file;
1428 	struct files_struct * files;
1429 	struct inode *inode;
1430 	struct proc_inode *ei;
1431 
1432 	if (fd == ~0U)
1433 		goto out;
1434 	if (!pid_alive(task))
1435 		goto out;
1436 
1437 	inode = proc_pid_make_inode(dir->i_sb, task, PROC_TID_FD_DIR+fd);
1438 	if (!inode)
1439 		goto out;
1440 	ei = PROC_I(inode);
1441 	files = get_files_struct(task);
1442 	if (!files)
1443 		goto out_unlock;
1444 	inode->i_mode = S_IFLNK;
1445 	rcu_read_lock();
1446 	file = fcheck_files(files, fd);
1447 	if (!file)
1448 		goto out_unlock2;
1449 	if (file->f_mode & 1)
1450 		inode->i_mode |= S_IRUSR | S_IXUSR;
1451 	if (file->f_mode & 2)
1452 		inode->i_mode |= S_IWUSR | S_IXUSR;
1453 	rcu_read_unlock();
1454 	put_files_struct(files);
1455 	inode->i_op = &proc_pid_link_inode_operations;
1456 	inode->i_size = 64;
1457 	ei->op.proc_get_link = proc_fd_link;
1458 	dentry->d_op = &tid_fd_dentry_operations;
1459 	d_add(dentry, inode);
1460 	return NULL;
1461 
1462 out_unlock2:
1463 	rcu_read_unlock();
1464 	put_files_struct(files);
1465 out_unlock:
1466 	iput(inode);
1467 out:
1468 	return ERR_PTR(-ENOENT);
1469 }
1470 
1471 static int proc_task_readdir(struct file * filp, void * dirent, filldir_t filldir);
1472 static struct dentry *proc_task_lookup(struct inode *dir, struct dentry * dentry, struct nameidata *nd);
1473 
1474 static struct file_operations proc_fd_operations = {
1475 	.read		= generic_read_dir,
1476 	.readdir	= proc_readfd,
1477 };
1478 
1479 static struct file_operations proc_task_operations = {
1480 	.read		= generic_read_dir,
1481 	.readdir	= proc_task_readdir,
1482 };
1483 
1484 /*
1485  * proc directories can do almost nothing..
1486  */
1487 static struct inode_operations proc_fd_inode_operations = {
1488 	.lookup		= proc_lookupfd,
1489 	.permission	= proc_permission,
1490 };
1491 
1492 static struct inode_operations proc_task_inode_operations = {
1493 	.lookup		= proc_task_lookup,
1494 	.permission	= proc_task_permission,
1495 };
1496 
1497 #ifdef CONFIG_SECURITY
1498 static ssize_t proc_pid_attr_read(struct file * file, char __user * buf,
1499 				  size_t count, loff_t *ppos)
1500 {
1501 	struct inode * inode = file->f_dentry->d_inode;
1502 	unsigned long page;
1503 	ssize_t length;
1504 	struct task_struct *task = proc_task(inode);
1505 
1506 	if (count > PAGE_SIZE)
1507 		count = PAGE_SIZE;
1508 	if (!(page = __get_free_page(GFP_KERNEL)))
1509 		return -ENOMEM;
1510 
1511 	length = security_getprocattr(task,
1512 				      (char*)file->f_dentry->d_name.name,
1513 				      (void*)page, count);
1514 	if (length >= 0)
1515 		length = simple_read_from_buffer(buf, count, ppos, (char *)page, length);
1516 	free_page(page);
1517 	return length;
1518 }
1519 
1520 static ssize_t proc_pid_attr_write(struct file * file, const char __user * buf,
1521 				   size_t count, loff_t *ppos)
1522 {
1523 	struct inode * inode = file->f_dentry->d_inode;
1524 	char *page;
1525 	ssize_t length;
1526 	struct task_struct *task = proc_task(inode);
1527 
1528 	if (count > PAGE_SIZE)
1529 		count = PAGE_SIZE;
1530 	if (*ppos != 0) {
1531 		/* No partial writes. */
1532 		return -EINVAL;
1533 	}
1534 	page = (char*)__get_free_page(GFP_USER);
1535 	if (!page)
1536 		return -ENOMEM;
1537 	length = -EFAULT;
1538 	if (copy_from_user(page, buf, count))
1539 		goto out;
1540 
1541 	length = security_setprocattr(task,
1542 				      (char*)file->f_dentry->d_name.name,
1543 				      (void*)page, count);
1544 out:
1545 	free_page((unsigned long) page);
1546 	return length;
1547 }
1548 
1549 static struct file_operations proc_pid_attr_operations = {
1550 	.read		= proc_pid_attr_read,
1551 	.write		= proc_pid_attr_write,
1552 };
1553 
1554 static struct file_operations proc_tid_attr_operations;
1555 static struct inode_operations proc_tid_attr_inode_operations;
1556 static struct file_operations proc_tgid_attr_operations;
1557 static struct inode_operations proc_tgid_attr_inode_operations;
1558 #endif
1559 
1560 static int get_tid_list(int index, unsigned int *tids, struct inode *dir);
1561 
1562 /* SMP-safe */
1563 static struct dentry *proc_pident_lookup(struct inode *dir,
1564 					 struct dentry *dentry,
1565 					 struct pid_entry *ents)
1566 {
1567 	struct inode *inode;
1568 	int error;
1569 	struct task_struct *task = proc_task(dir);
1570 	struct pid_entry *p;
1571 	struct proc_inode *ei;
1572 
1573 	error = -ENOENT;
1574 	inode = NULL;
1575 
1576 	if (!pid_alive(task))
1577 		goto out;
1578 
1579 	for (p = ents; p->name; p++) {
1580 		if (p->len != dentry->d_name.len)
1581 			continue;
1582 		if (!memcmp(dentry->d_name.name, p->name, p->len))
1583 			break;
1584 	}
1585 	if (!p->name)
1586 		goto out;
1587 
1588 	error = -EINVAL;
1589 	inode = proc_pid_make_inode(dir->i_sb, task, p->type);
1590 	if (!inode)
1591 		goto out;
1592 
1593 	ei = PROC_I(inode);
1594 	inode->i_mode = p->mode;
1595 	/*
1596 	 * Yes, it does not scale. And it should not. Don't add
1597 	 * new entries into /proc/<tgid>/ without very good reasons.
1598 	 */
1599 	switch(p->type) {
1600 		case PROC_TGID_TASK:
1601 			inode->i_nlink = 2 + get_tid_list(2, NULL, dir);
1602 			inode->i_op = &proc_task_inode_operations;
1603 			inode->i_fop = &proc_task_operations;
1604 			break;
1605 		case PROC_TID_FD:
1606 		case PROC_TGID_FD:
1607 			inode->i_nlink = 2;
1608 			inode->i_op = &proc_fd_inode_operations;
1609 			inode->i_fop = &proc_fd_operations;
1610 			break;
1611 		case PROC_TID_EXE:
1612 		case PROC_TGID_EXE:
1613 			inode->i_op = &proc_pid_link_inode_operations;
1614 			ei->op.proc_get_link = proc_exe_link;
1615 			break;
1616 		case PROC_TID_CWD:
1617 		case PROC_TGID_CWD:
1618 			inode->i_op = &proc_pid_link_inode_operations;
1619 			ei->op.proc_get_link = proc_cwd_link;
1620 			break;
1621 		case PROC_TID_ROOT:
1622 		case PROC_TGID_ROOT:
1623 			inode->i_op = &proc_pid_link_inode_operations;
1624 			ei->op.proc_get_link = proc_root_link;
1625 			break;
1626 		case PROC_TID_ENVIRON:
1627 		case PROC_TGID_ENVIRON:
1628 			inode->i_fop = &proc_info_file_operations;
1629 			ei->op.proc_read = proc_pid_environ;
1630 			break;
1631 		case PROC_TID_AUXV:
1632 		case PROC_TGID_AUXV:
1633 			inode->i_fop = &proc_info_file_operations;
1634 			ei->op.proc_read = proc_pid_auxv;
1635 			break;
1636 		case PROC_TID_STATUS:
1637 		case PROC_TGID_STATUS:
1638 			inode->i_fop = &proc_info_file_operations;
1639 			ei->op.proc_read = proc_pid_status;
1640 			break;
1641 		case PROC_TID_STAT:
1642 			inode->i_fop = &proc_info_file_operations;
1643 			ei->op.proc_read = proc_tid_stat;
1644 			break;
1645 		case PROC_TGID_STAT:
1646 			inode->i_fop = &proc_info_file_operations;
1647 			ei->op.proc_read = proc_tgid_stat;
1648 			break;
1649 		case PROC_TID_CMDLINE:
1650 		case PROC_TGID_CMDLINE:
1651 			inode->i_fop = &proc_info_file_operations;
1652 			ei->op.proc_read = proc_pid_cmdline;
1653 			break;
1654 		case PROC_TID_STATM:
1655 		case PROC_TGID_STATM:
1656 			inode->i_fop = &proc_info_file_operations;
1657 			ei->op.proc_read = proc_pid_statm;
1658 			break;
1659 		case PROC_TID_MAPS:
1660 		case PROC_TGID_MAPS:
1661 			inode->i_fop = &proc_maps_operations;
1662 			break;
1663 #ifdef CONFIG_NUMA
1664 		case PROC_TID_NUMA_MAPS:
1665 		case PROC_TGID_NUMA_MAPS:
1666 			inode->i_fop = &proc_numa_maps_operations;
1667 			break;
1668 #endif
1669 		case PROC_TID_MEM:
1670 		case PROC_TGID_MEM:
1671 			inode->i_op = &proc_mem_inode_operations;
1672 			inode->i_fop = &proc_mem_operations;
1673 			break;
1674 #ifdef CONFIG_SECCOMP
1675 		case PROC_TID_SECCOMP:
1676 		case PROC_TGID_SECCOMP:
1677 			inode->i_fop = &proc_seccomp_operations;
1678 			break;
1679 #endif /* CONFIG_SECCOMP */
1680 		case PROC_TID_MOUNTS:
1681 		case PROC_TGID_MOUNTS:
1682 			inode->i_fop = &proc_mounts_operations;
1683 			break;
1684 		case PROC_TID_SMAPS:
1685 		case PROC_TGID_SMAPS:
1686 			inode->i_fop = &proc_smaps_operations;
1687 			break;
1688 #ifdef CONFIG_SECURITY
1689 		case PROC_TID_ATTR:
1690 			inode->i_nlink = 2;
1691 			inode->i_op = &proc_tid_attr_inode_operations;
1692 			inode->i_fop = &proc_tid_attr_operations;
1693 			break;
1694 		case PROC_TGID_ATTR:
1695 			inode->i_nlink = 2;
1696 			inode->i_op = &proc_tgid_attr_inode_operations;
1697 			inode->i_fop = &proc_tgid_attr_operations;
1698 			break;
1699 		case PROC_TID_ATTR_CURRENT:
1700 		case PROC_TGID_ATTR_CURRENT:
1701 		case PROC_TID_ATTR_PREV:
1702 		case PROC_TGID_ATTR_PREV:
1703 		case PROC_TID_ATTR_EXEC:
1704 		case PROC_TGID_ATTR_EXEC:
1705 		case PROC_TID_ATTR_FSCREATE:
1706 		case PROC_TGID_ATTR_FSCREATE:
1707 			inode->i_fop = &proc_pid_attr_operations;
1708 			break;
1709 #endif
1710 #ifdef CONFIG_KALLSYMS
1711 		case PROC_TID_WCHAN:
1712 		case PROC_TGID_WCHAN:
1713 			inode->i_fop = &proc_info_file_operations;
1714 			ei->op.proc_read = proc_pid_wchan;
1715 			break;
1716 #endif
1717 #ifdef CONFIG_SCHEDSTATS
1718 		case PROC_TID_SCHEDSTAT:
1719 		case PROC_TGID_SCHEDSTAT:
1720 			inode->i_fop = &proc_info_file_operations;
1721 			ei->op.proc_read = proc_pid_schedstat;
1722 			break;
1723 #endif
1724 #ifdef CONFIG_CPUSETS
1725 		case PROC_TID_CPUSET:
1726 		case PROC_TGID_CPUSET:
1727 			inode->i_fop = &proc_cpuset_operations;
1728 			break;
1729 #endif
1730 		case PROC_TID_OOM_SCORE:
1731 		case PROC_TGID_OOM_SCORE:
1732 			inode->i_fop = &proc_info_file_operations;
1733 			ei->op.proc_read = proc_oom_score;
1734 			break;
1735 		case PROC_TID_OOM_ADJUST:
1736 		case PROC_TGID_OOM_ADJUST:
1737 			inode->i_fop = &proc_oom_adjust_operations;
1738 			break;
1739 #ifdef CONFIG_AUDITSYSCALL
1740 		case PROC_TID_LOGINUID:
1741 		case PROC_TGID_LOGINUID:
1742 			inode->i_fop = &proc_loginuid_operations;
1743 			break;
1744 #endif
1745 		default:
1746 			printk("procfs: impossible type (%d)",p->type);
1747 			iput(inode);
1748 			return ERR_PTR(-EINVAL);
1749 	}
1750 	dentry->d_op = &pid_dentry_operations;
1751 	d_add(dentry, inode);
1752 	return NULL;
1753 
1754 out:
1755 	return ERR_PTR(error);
1756 }
1757 
1758 static struct dentry *proc_tgid_base_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd){
1759 	return proc_pident_lookup(dir, dentry, tgid_base_stuff);
1760 }
1761 
1762 static struct dentry *proc_tid_base_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd){
1763 	return proc_pident_lookup(dir, dentry, tid_base_stuff);
1764 }
1765 
1766 static struct file_operations proc_tgid_base_operations = {
1767 	.read		= generic_read_dir,
1768 	.readdir	= proc_tgid_base_readdir,
1769 };
1770 
1771 static struct file_operations proc_tid_base_operations = {
1772 	.read		= generic_read_dir,
1773 	.readdir	= proc_tid_base_readdir,
1774 };
1775 
1776 static struct inode_operations proc_tgid_base_inode_operations = {
1777 	.lookup		= proc_tgid_base_lookup,
1778 };
1779 
1780 static struct inode_operations proc_tid_base_inode_operations = {
1781 	.lookup		= proc_tid_base_lookup,
1782 };
1783 
1784 #ifdef CONFIG_SECURITY
1785 static int proc_tgid_attr_readdir(struct file * filp,
1786 			     void * dirent, filldir_t filldir)
1787 {
1788 	return proc_pident_readdir(filp,dirent,filldir,
1789 				   tgid_attr_stuff,ARRAY_SIZE(tgid_attr_stuff));
1790 }
1791 
1792 static int proc_tid_attr_readdir(struct file * filp,
1793 			     void * dirent, filldir_t filldir)
1794 {
1795 	return proc_pident_readdir(filp,dirent,filldir,
1796 				   tid_attr_stuff,ARRAY_SIZE(tid_attr_stuff));
1797 }
1798 
1799 static struct file_operations proc_tgid_attr_operations = {
1800 	.read		= generic_read_dir,
1801 	.readdir	= proc_tgid_attr_readdir,
1802 };
1803 
1804 static struct file_operations proc_tid_attr_operations = {
1805 	.read		= generic_read_dir,
1806 	.readdir	= proc_tid_attr_readdir,
1807 };
1808 
1809 static struct dentry *proc_tgid_attr_lookup(struct inode *dir,
1810 				struct dentry *dentry, struct nameidata *nd)
1811 {
1812 	return proc_pident_lookup(dir, dentry, tgid_attr_stuff);
1813 }
1814 
1815 static struct dentry *proc_tid_attr_lookup(struct inode *dir,
1816 				struct dentry *dentry, struct nameidata *nd)
1817 {
1818 	return proc_pident_lookup(dir, dentry, tid_attr_stuff);
1819 }
1820 
1821 static struct inode_operations proc_tgid_attr_inode_operations = {
1822 	.lookup		= proc_tgid_attr_lookup,
1823 };
1824 
1825 static struct inode_operations proc_tid_attr_inode_operations = {
1826 	.lookup		= proc_tid_attr_lookup,
1827 };
1828 #endif
1829 
1830 /*
1831  * /proc/self:
1832  */
1833 static int proc_self_readlink(struct dentry *dentry, char __user *buffer,
1834 			      int buflen)
1835 {
1836 	char tmp[30];
1837 	sprintf(tmp, "%d", current->tgid);
1838 	return vfs_readlink(dentry,buffer,buflen,tmp);
1839 }
1840 
1841 static void *proc_self_follow_link(struct dentry *dentry, struct nameidata *nd)
1842 {
1843 	char tmp[30];
1844 	sprintf(tmp, "%d", current->tgid);
1845 	return ERR_PTR(vfs_follow_link(nd,tmp));
1846 }
1847 
1848 static struct inode_operations proc_self_inode_operations = {
1849 	.readlink	= proc_self_readlink,
1850 	.follow_link	= proc_self_follow_link,
1851 };
1852 
1853 /**
1854  * proc_pid_unhash -  Unhash /proc/@pid entry from the dcache.
1855  * @p: task that should be flushed.
1856  *
1857  * Drops the /proc/@pid dcache entry from the hash chains.
1858  *
1859  * Dropping /proc/@pid entries and detach_pid must be synchroneous,
1860  * otherwise e.g. /proc/@pid/exe might point to the wrong executable,
1861  * if the pid value is immediately reused. This is enforced by
1862  * - caller must acquire spin_lock(p->proc_lock)
1863  * - must be called before detach_pid()
1864  * - proc_pid_lookup acquires proc_lock, and checks that
1865  *   the target is not dead by looking at the attach count
1866  *   of PIDTYPE_PID.
1867  */
1868 
1869 struct dentry *proc_pid_unhash(struct task_struct *p)
1870 {
1871 	struct dentry *proc_dentry;
1872 
1873 	proc_dentry = p->proc_dentry;
1874 	if (proc_dentry != NULL) {
1875 
1876 		spin_lock(&dcache_lock);
1877 		spin_lock(&proc_dentry->d_lock);
1878 		if (!d_unhashed(proc_dentry)) {
1879 			dget_locked(proc_dentry);
1880 			__d_drop(proc_dentry);
1881 			spin_unlock(&proc_dentry->d_lock);
1882 		} else {
1883 			spin_unlock(&proc_dentry->d_lock);
1884 			proc_dentry = NULL;
1885 		}
1886 		spin_unlock(&dcache_lock);
1887 	}
1888 	return proc_dentry;
1889 }
1890 
1891 /**
1892  * proc_pid_flush - recover memory used by stale /proc/@pid/x entries
1893  * @proc_dentry: directoy to prune.
1894  *
1895  * Shrink the /proc directory that was used by the just killed thread.
1896  */
1897 
1898 void proc_pid_flush(struct dentry *proc_dentry)
1899 {
1900 	might_sleep();
1901 	if(proc_dentry != NULL) {
1902 		shrink_dcache_parent(proc_dentry);
1903 		dput(proc_dentry);
1904 	}
1905 }
1906 
1907 /* SMP-safe */
1908 struct dentry *proc_pid_lookup(struct inode *dir, struct dentry * dentry, struct nameidata *nd)
1909 {
1910 	struct task_struct *task;
1911 	struct inode *inode;
1912 	struct proc_inode *ei;
1913 	unsigned tgid;
1914 	int died;
1915 
1916 	if (dentry->d_name.len == 4 && !memcmp(dentry->d_name.name,"self",4)) {
1917 		inode = new_inode(dir->i_sb);
1918 		if (!inode)
1919 			return ERR_PTR(-ENOMEM);
1920 		ei = PROC_I(inode);
1921 		inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
1922 		inode->i_ino = fake_ino(0, PROC_TGID_INO);
1923 		ei->pde = NULL;
1924 		inode->i_mode = S_IFLNK|S_IRWXUGO;
1925 		inode->i_uid = inode->i_gid = 0;
1926 		inode->i_size = 64;
1927 		inode->i_op = &proc_self_inode_operations;
1928 		d_add(dentry, inode);
1929 		return NULL;
1930 	}
1931 	tgid = name_to_int(dentry);
1932 	if (tgid == ~0U)
1933 		goto out;
1934 
1935 	read_lock(&tasklist_lock);
1936 	task = find_task_by_pid(tgid);
1937 	if (task)
1938 		get_task_struct(task);
1939 	read_unlock(&tasklist_lock);
1940 	if (!task)
1941 		goto out;
1942 
1943 	inode = proc_pid_make_inode(dir->i_sb, task, PROC_TGID_INO);
1944 
1945 
1946 	if (!inode) {
1947 		put_task_struct(task);
1948 		goto out;
1949 	}
1950 	inode->i_mode = S_IFDIR|S_IRUGO|S_IXUGO;
1951 	inode->i_op = &proc_tgid_base_inode_operations;
1952 	inode->i_fop = &proc_tgid_base_operations;
1953 	inode->i_flags|=S_IMMUTABLE;
1954 #ifdef CONFIG_SECURITY
1955 	inode->i_nlink = 5;
1956 #else
1957 	inode->i_nlink = 4;
1958 #endif
1959 
1960 	dentry->d_op = &pid_base_dentry_operations;
1961 
1962 	died = 0;
1963 	d_add(dentry, inode);
1964 	spin_lock(&task->proc_lock);
1965 	task->proc_dentry = dentry;
1966 	if (!pid_alive(task)) {
1967 		dentry = proc_pid_unhash(task);
1968 		died = 1;
1969 	}
1970 	spin_unlock(&task->proc_lock);
1971 
1972 	put_task_struct(task);
1973 	if (died) {
1974 		proc_pid_flush(dentry);
1975 		goto out;
1976 	}
1977 	return NULL;
1978 out:
1979 	return ERR_PTR(-ENOENT);
1980 }
1981 
1982 /* SMP-safe */
1983 static struct dentry *proc_task_lookup(struct inode *dir, struct dentry * dentry, struct nameidata *nd)
1984 {
1985 	struct task_struct *task;
1986 	struct task_struct *leader = proc_task(dir);
1987 	struct inode *inode;
1988 	unsigned tid;
1989 
1990 	tid = name_to_int(dentry);
1991 	if (tid == ~0U)
1992 		goto out;
1993 
1994 	read_lock(&tasklist_lock);
1995 	task = find_task_by_pid(tid);
1996 	if (task)
1997 		get_task_struct(task);
1998 	read_unlock(&tasklist_lock);
1999 	if (!task)
2000 		goto out;
2001 	if (leader->tgid != task->tgid)
2002 		goto out_drop_task;
2003 
2004 	inode = proc_pid_make_inode(dir->i_sb, task, PROC_TID_INO);
2005 
2006 
2007 	if (!inode)
2008 		goto out_drop_task;
2009 	inode->i_mode = S_IFDIR|S_IRUGO|S_IXUGO;
2010 	inode->i_op = &proc_tid_base_inode_operations;
2011 	inode->i_fop = &proc_tid_base_operations;
2012 	inode->i_flags|=S_IMMUTABLE;
2013 #ifdef CONFIG_SECURITY
2014 	inode->i_nlink = 4;
2015 #else
2016 	inode->i_nlink = 3;
2017 #endif
2018 
2019 	dentry->d_op = &pid_base_dentry_operations;
2020 
2021 	d_add(dentry, inode);
2022 
2023 	put_task_struct(task);
2024 	return NULL;
2025 out_drop_task:
2026 	put_task_struct(task);
2027 out:
2028 	return ERR_PTR(-ENOENT);
2029 }
2030 
2031 #define PROC_NUMBUF 10
2032 #define PROC_MAXPIDS 20
2033 
2034 /*
2035  * Get a few tgid's to return for filldir - we need to hold the
2036  * tasklist lock while doing this, and we must release it before
2037  * we actually do the filldir itself, so we use a temp buffer..
2038  */
2039 static int get_tgid_list(int index, unsigned long version, unsigned int *tgids)
2040 {
2041 	struct task_struct *p;
2042 	int nr_tgids = 0;
2043 
2044 	index--;
2045 	read_lock(&tasklist_lock);
2046 	p = NULL;
2047 	if (version) {
2048 		p = find_task_by_pid(version);
2049 		if (p && !thread_group_leader(p))
2050 			p = NULL;
2051 	}
2052 
2053 	if (p)
2054 		index = 0;
2055 	else
2056 		p = next_task(&init_task);
2057 
2058 	for ( ; p != &init_task; p = next_task(p)) {
2059 		int tgid = p->pid;
2060 		if (!pid_alive(p))
2061 			continue;
2062 		if (--index >= 0)
2063 			continue;
2064 		tgids[nr_tgids] = tgid;
2065 		nr_tgids++;
2066 		if (nr_tgids >= PROC_MAXPIDS)
2067 			break;
2068 	}
2069 	read_unlock(&tasklist_lock);
2070 	return nr_tgids;
2071 }
2072 
2073 /*
2074  * Get a few tid's to return for filldir - we need to hold the
2075  * tasklist lock while doing this, and we must release it before
2076  * we actually do the filldir itself, so we use a temp buffer..
2077  */
2078 static int get_tid_list(int index, unsigned int *tids, struct inode *dir)
2079 {
2080 	struct task_struct *leader_task = proc_task(dir);
2081 	struct task_struct *task = leader_task;
2082 	int nr_tids = 0;
2083 
2084 	index -= 2;
2085 	read_lock(&tasklist_lock);
2086 	/*
2087 	 * The starting point task (leader_task) might be an already
2088 	 * unlinked task, which cannot be used to access the task-list
2089 	 * via next_thread().
2090 	 */
2091 	if (pid_alive(task)) do {
2092 		int tid = task->pid;
2093 
2094 		if (--index >= 0)
2095 			continue;
2096 		if (tids != NULL)
2097 			tids[nr_tids] = tid;
2098 		nr_tids++;
2099 		if (nr_tids >= PROC_MAXPIDS)
2100 			break;
2101 	} while ((task = next_thread(task)) != leader_task);
2102 	read_unlock(&tasklist_lock);
2103 	return nr_tids;
2104 }
2105 
2106 /* for the /proc/ directory itself, after non-process stuff has been done */
2107 int proc_pid_readdir(struct file * filp, void * dirent, filldir_t filldir)
2108 {
2109 	unsigned int tgid_array[PROC_MAXPIDS];
2110 	char buf[PROC_NUMBUF];
2111 	unsigned int nr = filp->f_pos - FIRST_PROCESS_ENTRY;
2112 	unsigned int nr_tgids, i;
2113 	int next_tgid;
2114 
2115 	if (!nr) {
2116 		ino_t ino = fake_ino(0,PROC_TGID_INO);
2117 		if (filldir(dirent, "self", 4, filp->f_pos, ino, DT_LNK) < 0)
2118 			return 0;
2119 		filp->f_pos++;
2120 		nr++;
2121 	}
2122 
2123 	/* f_version caches the tgid value that the last readdir call couldn't
2124 	 * return. lseek aka telldir automagically resets f_version to 0.
2125 	 */
2126 	next_tgid = filp->f_version;
2127 	filp->f_version = 0;
2128 	for (;;) {
2129 		nr_tgids = get_tgid_list(nr, next_tgid, tgid_array);
2130 		if (!nr_tgids) {
2131 			/* no more entries ! */
2132 			break;
2133 		}
2134 		next_tgid = 0;
2135 
2136 		/* do not use the last found pid, reserve it for next_tgid */
2137 		if (nr_tgids == PROC_MAXPIDS) {
2138 			nr_tgids--;
2139 			next_tgid = tgid_array[nr_tgids];
2140 		}
2141 
2142 		for (i=0;i<nr_tgids;i++) {
2143 			int tgid = tgid_array[i];
2144 			ino_t ino = fake_ino(tgid,PROC_TGID_INO);
2145 			unsigned long j = PROC_NUMBUF;
2146 
2147 			do
2148 				buf[--j] = '0' + (tgid % 10);
2149 			while ((tgid /= 10) != 0);
2150 
2151 			if (filldir(dirent, buf+j, PROC_NUMBUF-j, filp->f_pos, ino, DT_DIR) < 0) {
2152 				/* returning this tgid failed, save it as the first
2153 				 * pid for the next readir call */
2154 				filp->f_version = tgid_array[i];
2155 				goto out;
2156 			}
2157 			filp->f_pos++;
2158 			nr++;
2159 		}
2160 	}
2161 out:
2162 	return 0;
2163 }
2164 
2165 /* for the /proc/TGID/task/ directories */
2166 static int proc_task_readdir(struct file * filp, void * dirent, filldir_t filldir)
2167 {
2168 	unsigned int tid_array[PROC_MAXPIDS];
2169 	char buf[PROC_NUMBUF];
2170 	unsigned int nr_tids, i;
2171 	struct dentry *dentry = filp->f_dentry;
2172 	struct inode *inode = dentry->d_inode;
2173 	int retval = -ENOENT;
2174 	ino_t ino;
2175 	unsigned long pos = filp->f_pos;  /* avoiding "long long" filp->f_pos */
2176 
2177 	if (!pid_alive(proc_task(inode)))
2178 		goto out;
2179 	retval = 0;
2180 
2181 	switch (pos) {
2182 	case 0:
2183 		ino = inode->i_ino;
2184 		if (filldir(dirent, ".", 1, pos, ino, DT_DIR) < 0)
2185 			goto out;
2186 		pos++;
2187 		/* fall through */
2188 	case 1:
2189 		ino = parent_ino(dentry);
2190 		if (filldir(dirent, "..", 2, pos, ino, DT_DIR) < 0)
2191 			goto out;
2192 		pos++;
2193 		/* fall through */
2194 	}
2195 
2196 	nr_tids = get_tid_list(pos, tid_array, inode);
2197 	inode->i_nlink = pos + nr_tids;
2198 
2199 	for (i = 0; i < nr_tids; i++) {
2200 		unsigned long j = PROC_NUMBUF;
2201 		int tid = tid_array[i];
2202 
2203 		ino = fake_ino(tid,PROC_TID_INO);
2204 
2205 		do
2206 			buf[--j] = '0' + (tid % 10);
2207 		while ((tid /= 10) != 0);
2208 
2209 		if (filldir(dirent, buf+j, PROC_NUMBUF-j, pos, ino, DT_DIR) < 0)
2210 			break;
2211 		pos++;
2212 	}
2213 out:
2214 	filp->f_pos = pos;
2215 	return retval;
2216 }
2217