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[linux-2.6.git] / fs / proc / base.c
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 #include <asm/uaccess.h>
17
18 #include <linux/config.h>
19 #include <linux/errno.h>
20 #include <linux/time.h>
21 #include <linux/proc_fs.h>
22 #include <linux/stat.h>
23 #include <linux/init.h>
24 #include <linux/file.h>
25 #include <linux/string.h>
26 #include <linux/seq_file.h>
27 #include <linux/namei.h>
28 #include <linux/namespace.h>
29 #include <linux/mm.h>
30 #include <linux/smp_lock.h>
31 #include <linux/kallsyms.h>
32 #include <linux/mount.h>
33 #include <linux/security.h>
34 #include <linux/ptrace.h>
35 #include <linux/seccomp.h>
36 #include <linux/cpuset.h>
37 #include <linux/audit.h>
38 #include "internal.h"
39
40 /*
41  * For hysterical raisins we keep the same inumbers as in the old procfs.
42  * Feel free to change the macro below - just keep the range distinct from
43  * inumbers of the rest of procfs (currently those are in 0x0000--0xffff).
44  * As soon as we'll get a separate superblock we will be able to forget
45  * about magical ranges too.
46  */
47
48 #define fake_ino(pid,ino) (((pid)<<16)|(ino))
49
50 enum pid_directory_inos {
51         PROC_TGID_INO = 2,
52         PROC_TGID_TASK,
53         PROC_TGID_STATUS,
54         PROC_TGID_MEM,
55 #ifdef CONFIG_SECCOMP
56         PROC_TGID_SECCOMP,
57 #endif
58         PROC_TGID_CWD,
59         PROC_TGID_ROOT,
60         PROC_TGID_EXE,
61         PROC_TGID_FD,
62         PROC_TGID_ENVIRON,
63         PROC_TGID_AUXV,
64         PROC_TGID_CMDLINE,
65         PROC_TGID_STAT,
66         PROC_TGID_STATM,
67         PROC_TGID_MAPS,
68         PROC_TGID_MOUNTS,
69         PROC_TGID_WCHAN,
70 #ifdef CONFIG_SCHEDSTATS
71         PROC_TGID_SCHEDSTAT,
72 #endif
73 #ifdef CONFIG_CPUSETS
74         PROC_TGID_CPUSET,
75 #endif
76 #ifdef CONFIG_SECURITY
77         PROC_TGID_ATTR,
78         PROC_TGID_ATTR_CURRENT,
79         PROC_TGID_ATTR_PREV,
80         PROC_TGID_ATTR_EXEC,
81         PROC_TGID_ATTR_FSCREATE,
82 #endif
83 #ifdef CONFIG_AUDITSYSCALL
84         PROC_TGID_LOGINUID,
85 #endif
86         PROC_TGID_FD_DIR,
87         PROC_TGID_OOM_SCORE,
88         PROC_TGID_OOM_ADJUST,
89         PROC_TID_INO,
90         PROC_TID_STATUS,
91         PROC_TID_MEM,
92 #ifdef CONFIG_SECCOMP
93         PROC_TID_SECCOMP,
94 #endif
95         PROC_TID_CWD,
96         PROC_TID_ROOT,
97         PROC_TID_EXE,
98         PROC_TID_FD,
99         PROC_TID_ENVIRON,
100         PROC_TID_AUXV,
101         PROC_TID_CMDLINE,
102         PROC_TID_STAT,
103         PROC_TID_STATM,
104         PROC_TID_MAPS,
105         PROC_TID_MOUNTS,
106         PROC_TID_WCHAN,
107 #ifdef CONFIG_SCHEDSTATS
108         PROC_TID_SCHEDSTAT,
109 #endif
110 #ifdef CONFIG_CPUSETS
111         PROC_TID_CPUSET,
112 #endif
113 #ifdef CONFIG_SECURITY
114         PROC_TID_ATTR,
115         PROC_TID_ATTR_CURRENT,
116         PROC_TID_ATTR_PREV,
117         PROC_TID_ATTR_EXEC,
118         PROC_TID_ATTR_FSCREATE,
119 #endif
120 #ifdef CONFIG_AUDITSYSCALL
121         PROC_TID_LOGINUID,
122 #endif
123         PROC_TID_FD_DIR = 0x8000,       /* 0x8000-0xffff */
124         PROC_TID_OOM_SCORE,
125         PROC_TID_OOM_ADJUST,
126 };
127
128 struct pid_entry {
129         int type;
130         int len;
131         char *name;
132         mode_t mode;
133 };
134
135 #define E(type,name,mode) {(type),sizeof(name)-1,(name),(mode)}
136
137 static struct pid_entry tgid_base_stuff[] = {
138         E(PROC_TGID_TASK,      "task",    S_IFDIR|S_IRUGO|S_IXUGO),
139         E(PROC_TGID_FD,        "fd",      S_IFDIR|S_IRUSR|S_IXUSR),
140         E(PROC_TGID_ENVIRON,   "environ", S_IFREG|S_IRUSR),
141         E(PROC_TGID_AUXV,      "auxv",    S_IFREG|S_IRUSR),
142         E(PROC_TGID_STATUS,    "status",  S_IFREG|S_IRUGO),
143         E(PROC_TGID_CMDLINE,   "cmdline", S_IFREG|S_IRUGO),
144         E(PROC_TGID_STAT,      "stat",    S_IFREG|S_IRUGO),
145         E(PROC_TGID_STATM,     "statm",   S_IFREG|S_IRUGO),
146         E(PROC_TGID_MAPS,      "maps",    S_IFREG|S_IRUGO),
147         E(PROC_TGID_MEM,       "mem",     S_IFREG|S_IRUSR|S_IWUSR),
148 #ifdef CONFIG_SECCOMP
149         E(PROC_TGID_SECCOMP,   "seccomp", S_IFREG|S_IRUSR|S_IWUSR),
150 #endif
151         E(PROC_TGID_CWD,       "cwd",     S_IFLNK|S_IRWXUGO),
152         E(PROC_TGID_ROOT,      "root",    S_IFLNK|S_IRWXUGO),
153         E(PROC_TGID_EXE,       "exe",     S_IFLNK|S_IRWXUGO),
154         E(PROC_TGID_MOUNTS,    "mounts",  S_IFREG|S_IRUGO),
155 #ifdef CONFIG_SECURITY
156         E(PROC_TGID_ATTR,      "attr",    S_IFDIR|S_IRUGO|S_IXUGO),
157 #endif
158 #ifdef CONFIG_KALLSYMS
159         E(PROC_TGID_WCHAN,     "wchan",   S_IFREG|S_IRUGO),
160 #endif
161 #ifdef CONFIG_SCHEDSTATS
162         E(PROC_TGID_SCHEDSTAT, "schedstat", S_IFREG|S_IRUGO),
163 #endif
164 #ifdef CONFIG_CPUSETS
165         E(PROC_TGID_CPUSET,    "cpuset",  S_IFREG|S_IRUGO),
166 #endif
167         E(PROC_TGID_OOM_SCORE, "oom_score",S_IFREG|S_IRUGO),
168         E(PROC_TGID_OOM_ADJUST,"oom_adj", S_IFREG|S_IRUGO|S_IWUSR),
169 #ifdef CONFIG_AUDITSYSCALL
170         E(PROC_TGID_LOGINUID, "loginuid", S_IFREG|S_IWUSR|S_IRUGO),
171 #endif
172         {0,0,NULL,0}
173 };
174 static struct pid_entry tid_base_stuff[] = {
175         E(PROC_TID_FD,         "fd",      S_IFDIR|S_IRUSR|S_IXUSR),
176         E(PROC_TID_ENVIRON,    "environ", S_IFREG|S_IRUSR),
177         E(PROC_TID_AUXV,       "auxv",    S_IFREG|S_IRUSR),
178         E(PROC_TID_STATUS,     "status",  S_IFREG|S_IRUGO),
179         E(PROC_TID_CMDLINE,    "cmdline", S_IFREG|S_IRUGO),
180         E(PROC_TID_STAT,       "stat",    S_IFREG|S_IRUGO),
181         E(PROC_TID_STATM,      "statm",   S_IFREG|S_IRUGO),
182         E(PROC_TID_MAPS,       "maps",    S_IFREG|S_IRUGO),
183         E(PROC_TID_MEM,        "mem",     S_IFREG|S_IRUSR|S_IWUSR),
184 #ifdef CONFIG_SECCOMP
185         E(PROC_TID_SECCOMP,    "seccomp", S_IFREG|S_IRUSR|S_IWUSR),
186 #endif
187         E(PROC_TID_CWD,        "cwd",     S_IFLNK|S_IRWXUGO),
188         E(PROC_TID_ROOT,       "root",    S_IFLNK|S_IRWXUGO),
189         E(PROC_TID_EXE,        "exe",     S_IFLNK|S_IRWXUGO),
190         E(PROC_TID_MOUNTS,     "mounts",  S_IFREG|S_IRUGO),
191 #ifdef CONFIG_SECURITY
192         E(PROC_TID_ATTR,       "attr",    S_IFDIR|S_IRUGO|S_IXUGO),
193 #endif
194 #ifdef CONFIG_KALLSYMS
195         E(PROC_TID_WCHAN,      "wchan",   S_IFREG|S_IRUGO),
196 #endif
197 #ifdef CONFIG_SCHEDSTATS
198         E(PROC_TID_SCHEDSTAT, "schedstat",S_IFREG|S_IRUGO),
199 #endif
200 #ifdef CONFIG_CPUSETS
201         E(PROC_TID_CPUSET,     "cpuset",  S_IFREG|S_IRUGO),
202 #endif
203         E(PROC_TID_OOM_SCORE,  "oom_score",S_IFREG|S_IRUGO),
204         E(PROC_TID_OOM_ADJUST, "oom_adj", S_IFREG|S_IRUGO|S_IWUSR),
205 #ifdef CONFIG_AUDITSYSCALL
206         E(PROC_TID_LOGINUID, "loginuid", S_IFREG|S_IWUSR|S_IRUGO),
207 #endif
208         {0,0,NULL,0}
209 };
210
211 #ifdef CONFIG_SECURITY
212 static struct pid_entry tgid_attr_stuff[] = {
213         E(PROC_TGID_ATTR_CURRENT,  "current",  S_IFREG|S_IRUGO|S_IWUGO),
214         E(PROC_TGID_ATTR_PREV,     "prev",     S_IFREG|S_IRUGO),
215         E(PROC_TGID_ATTR_EXEC,     "exec",     S_IFREG|S_IRUGO|S_IWUGO),
216         E(PROC_TGID_ATTR_FSCREATE, "fscreate", S_IFREG|S_IRUGO|S_IWUGO),
217         {0,0,NULL,0}
218 };
219 static struct pid_entry tid_attr_stuff[] = {
220         E(PROC_TID_ATTR_CURRENT,   "current",  S_IFREG|S_IRUGO|S_IWUGO),
221         E(PROC_TID_ATTR_PREV,      "prev",     S_IFREG|S_IRUGO),
222         E(PROC_TID_ATTR_EXEC,      "exec",     S_IFREG|S_IRUGO|S_IWUGO),
223         E(PROC_TID_ATTR_FSCREATE,  "fscreate", S_IFREG|S_IRUGO|S_IWUGO),
224         {0,0,NULL,0}
225 };
226 #endif
227
228 #undef E
229
230 static int proc_fd_link(struct inode *inode, struct dentry **dentry, struct vfsmount **mnt)
231 {
232         struct task_struct *task = proc_task(inode);
233         struct files_struct *files;
234         struct file *file;
235         int fd = proc_type(inode) - PROC_TID_FD_DIR;
236
237         files = get_files_struct(task);
238         if (files) {
239                 spin_lock(&files->file_lock);
240                 file = fcheck_files(files, fd);
241                 if (file) {
242                         *mnt = mntget(file->f_vfsmnt);
243                         *dentry = dget(file->f_dentry);
244                         spin_unlock(&files->file_lock);
245                         put_files_struct(files);
246                         return 0;
247                 }
248                 spin_unlock(&files->file_lock);
249                 put_files_struct(files);
250         }
251         return -ENOENT;
252 }
253
254 static int proc_cwd_link(struct inode *inode, struct dentry **dentry, struct vfsmount **mnt)
255 {
256         struct fs_struct *fs;
257         int result = -ENOENT;
258         task_lock(proc_task(inode));
259         fs = proc_task(inode)->fs;
260         if(fs)
261                 atomic_inc(&fs->count);
262         task_unlock(proc_task(inode));
263         if (fs) {
264                 read_lock(&fs->lock);
265                 *mnt = mntget(fs->pwdmnt);
266                 *dentry = dget(fs->pwd);
267                 read_unlock(&fs->lock);
268                 result = 0;
269                 put_fs_struct(fs);
270         }
271         return result;
272 }
273
274 static int proc_root_link(struct inode *inode, struct dentry **dentry, struct vfsmount **mnt)
275 {
276         struct fs_struct *fs;
277         int result = -ENOENT;
278         task_lock(proc_task(inode));
279         fs = proc_task(inode)->fs;
280         if(fs)
281                 atomic_inc(&fs->count);
282         task_unlock(proc_task(inode));
283         if (fs) {
284                 read_lock(&fs->lock);
285                 *mnt = mntget(fs->rootmnt);
286                 *dentry = dget(fs->root);
287                 read_unlock(&fs->lock);
288                 result = 0;
289                 put_fs_struct(fs);
290         }
291         return result;
292 }
293
294 #define MAY_PTRACE(task) \
295         (task == current || \
296         (task->parent == current && \
297         (task->ptrace & PT_PTRACED) && \
298          (task->state == TASK_STOPPED || task->state == TASK_TRACED) && \
299          security_ptrace(current,task) == 0))
300
301 static int may_ptrace_attach(struct task_struct *task)
302 {
303         int retval = 0;
304
305         task_lock(task);
306
307         if (!task->mm)
308                 goto out;
309         if (((current->uid != task->euid) ||
310              (current->uid != task->suid) ||
311              (current->uid != task->uid) ||
312              (current->gid != task->egid) ||
313              (current->gid != task->sgid) ||
314              (current->gid != task->gid)) && !capable(CAP_SYS_PTRACE))
315                 goto out;
316         rmb();
317         if (!task->mm->dumpable && !capable(CAP_SYS_PTRACE))
318                 goto out;
319         if (security_ptrace(current, task))
320                 goto out;
321
322         retval = 1;
323 out:
324         task_unlock(task);
325         return retval;
326 }
327
328 static int proc_pid_environ(struct task_struct *task, char * buffer)
329 {
330         int res = 0;
331         struct mm_struct *mm = get_task_mm(task);
332         if (mm) {
333                 unsigned int len = mm->env_end - mm->env_start;
334                 if (len > PAGE_SIZE)
335                         len = PAGE_SIZE;
336                 res = access_process_vm(task, mm->env_start, buffer, len, 0);
337                 if (!may_ptrace_attach(task))
338                         res = -ESRCH;
339                 mmput(mm);
340         }
341         return res;
342 }
343
344 static int proc_pid_cmdline(struct task_struct *task, char * buffer)
345 {
346         int res = 0;
347         unsigned int len;
348         struct mm_struct *mm = get_task_mm(task);
349         if (!mm)
350                 goto out;
351         if (!mm->arg_end)
352                 goto out_mm;    /* Shh! No looking before we're done */
353
354         len = mm->arg_end - mm->arg_start;
355  
356         if (len > PAGE_SIZE)
357                 len = PAGE_SIZE;
358  
359         res = access_process_vm(task, mm->arg_start, buffer, len, 0);
360
361         // If the nul at the end of args has been overwritten, then
362         // assume application is using setproctitle(3).
363         if (res > 0 && buffer[res-1] != '\0' && len < PAGE_SIZE) {
364                 len = strnlen(buffer, res);
365                 if (len < res) {
366                     res = len;
367                 } else {
368                         len = mm->env_end - mm->env_start;
369                         if (len > PAGE_SIZE - res)
370                                 len = PAGE_SIZE - res;
371                         res += access_process_vm(task, mm->env_start, buffer+res, len, 0);
372                         res = strnlen(buffer, res);
373                 }
374         }
375 out_mm:
376         mmput(mm);
377 out:
378         return res;
379 }
380
381 static int proc_pid_auxv(struct task_struct *task, char *buffer)
382 {
383         int res = 0;
384         struct mm_struct *mm = get_task_mm(task);
385         if (mm) {
386                 unsigned int nwords = 0;
387                 do
388                         nwords += 2;
389                 while (mm->saved_auxv[nwords - 2] != 0); /* AT_NULL */
390                 res = nwords * sizeof(mm->saved_auxv[0]);
391                 if (res > PAGE_SIZE)
392                         res = PAGE_SIZE;
393                 memcpy(buffer, mm->saved_auxv, res);
394                 mmput(mm);
395         }
396         return res;
397 }
398
399
400 #ifdef CONFIG_KALLSYMS
401 /*
402  * Provides a wchan file via kallsyms in a proper one-value-per-file format.
403  * Returns the resolved symbol.  If that fails, simply return the address.
404  */
405 static int proc_pid_wchan(struct task_struct *task, char *buffer)
406 {
407         char *modname;
408         const char *sym_name;
409         unsigned long wchan, size, offset;
410         char namebuf[KSYM_NAME_LEN+1];
411
412         wchan = get_wchan(task);
413
414         sym_name = kallsyms_lookup(wchan, &size, &offset, &modname, namebuf);
415         if (sym_name)
416                 return sprintf(buffer, "%s", sym_name);
417         return sprintf(buffer, "%lu", wchan);
418 }
419 #endif /* CONFIG_KALLSYMS */
420
421 #ifdef CONFIG_SCHEDSTATS
422 /*
423  * Provides /proc/PID/schedstat
424  */
425 static int proc_pid_schedstat(struct task_struct *task, char *buffer)
426 {
427         return sprintf(buffer, "%lu %lu %lu\n",
428                         task->sched_info.cpu_time,
429                         task->sched_info.run_delay,
430                         task->sched_info.pcnt);
431 }
432 #endif
433
434 /* The badness from the OOM killer */
435 unsigned long badness(struct task_struct *p, unsigned long uptime);
436 static int proc_oom_score(struct task_struct *task, char *buffer)
437 {
438         unsigned long points;
439         struct timespec uptime;
440
441         do_posix_clock_monotonic_gettime(&uptime);
442         points = badness(task, uptime.tv_sec);
443         return sprintf(buffer, "%lu\n", points);
444 }
445
446 /************************************************************************/
447 /*                       Here the fs part begins                        */
448 /************************************************************************/
449
450 /* permission checks */
451
452 static int proc_check_root(struct inode *inode)
453 {
454         struct dentry *de, *base, *root;
455         struct vfsmount *our_vfsmnt, *vfsmnt, *mnt;
456         int res = 0;
457
458         if (proc_root_link(inode, &root, &vfsmnt)) /* Ewww... */
459                 return -ENOENT;
460         read_lock(&current->fs->lock);
461         our_vfsmnt = mntget(current->fs->rootmnt);
462         base = dget(current->fs->root);
463         read_unlock(&current->fs->lock);
464
465         spin_lock(&vfsmount_lock);
466         de = root;
467         mnt = vfsmnt;
468
469         while (vfsmnt != our_vfsmnt) {
470                 if (vfsmnt == vfsmnt->mnt_parent)
471                         goto out;
472                 de = vfsmnt->mnt_mountpoint;
473                 vfsmnt = vfsmnt->mnt_parent;
474         }
475
476         if (!is_subdir(de, base))
477                 goto out;
478         spin_unlock(&vfsmount_lock);
479
480 exit:
481         dput(base);
482         mntput(our_vfsmnt);
483         dput(root);
484         mntput(mnt);
485         return res;
486 out:
487         spin_unlock(&vfsmount_lock);
488         res = -EACCES;
489         goto exit;
490 }
491
492 static int proc_permission(struct inode *inode, int mask, struct nameidata *nd)
493 {
494         if (generic_permission(inode, mask, NULL) != 0)
495                 return -EACCES;
496         return proc_check_root(inode);
497 }
498
499 extern struct seq_operations proc_pid_maps_op;
500 static int maps_open(struct inode *inode, struct file *file)
501 {
502         struct task_struct *task = proc_task(inode);
503         int ret = seq_open(file, &proc_pid_maps_op);
504         if (!ret) {
505                 struct seq_file *m = file->private_data;
506                 m->private = task;
507         }
508         return ret;
509 }
510
511 static struct file_operations proc_maps_operations = {
512         .open           = maps_open,
513         .read           = seq_read,
514         .llseek         = seq_lseek,
515         .release        = seq_release,
516 };
517
518 extern struct seq_operations mounts_op;
519 static int mounts_open(struct inode *inode, struct file *file)
520 {
521         struct task_struct *task = proc_task(inode);
522         int ret = seq_open(file, &mounts_op);
523
524         if (!ret) {
525                 struct seq_file *m = file->private_data;
526                 struct namespace *namespace;
527                 task_lock(task);
528                 namespace = task->namespace;
529                 if (namespace)
530                         get_namespace(namespace);
531                 task_unlock(task);
532
533                 if (namespace)
534                         m->private = namespace;
535                 else {
536                         seq_release(inode, file);
537                         ret = -EINVAL;
538                 }
539         }
540         return ret;
541 }
542
543 static int mounts_release(struct inode *inode, struct file *file)
544 {
545         struct seq_file *m = file->private_data;
546         struct namespace *namespace = m->private;
547         put_namespace(namespace);
548         return seq_release(inode, file);
549 }
550
551 static struct file_operations proc_mounts_operations = {
552         .open           = mounts_open,
553         .read           = seq_read,
554         .llseek         = seq_lseek,
555         .release        = mounts_release,
556 };
557
558 #define PROC_BLOCK_SIZE (3*1024)                /* 4K page size but our output routines use some slack for overruns */
559
560 static ssize_t proc_info_read(struct file * file, char __user * buf,
561                           size_t count, loff_t *ppos)
562 {
563         struct inode * inode = file->f_dentry->d_inode;
564         unsigned long page;
565         ssize_t length;
566         struct task_struct *task = proc_task(inode);
567
568         if (count > PROC_BLOCK_SIZE)
569                 count = PROC_BLOCK_SIZE;
570         if (!(page = __get_free_page(GFP_KERNEL)))
571                 return -ENOMEM;
572
573         length = PROC_I(inode)->op.proc_read(task, (char*)page);
574
575         if (length >= 0)
576                 length = simple_read_from_buffer(buf, count, ppos, (char *)page, length);
577         free_page(page);
578         return length;
579 }
580
581 static struct file_operations proc_info_file_operations = {
582         .read           = proc_info_read,
583 };
584
585 static int mem_open(struct inode* inode, struct file* file)
586 {
587         file->private_data = (void*)((long)current->self_exec_id);
588         return 0;
589 }
590
591 static ssize_t mem_read(struct file * file, char __user * buf,
592                         size_t count, loff_t *ppos)
593 {
594         struct task_struct *task = proc_task(file->f_dentry->d_inode);
595         char *page;
596         unsigned long src = *ppos;
597         int ret = -ESRCH;
598         struct mm_struct *mm;
599
600         if (!MAY_PTRACE(task) || !may_ptrace_attach(task))
601                 goto out;
602
603         ret = -ENOMEM;
604         page = (char *)__get_free_page(GFP_USER);
605         if (!page)
606                 goto out;
607
608         ret = 0;
609  
610         mm = get_task_mm(task);
611         if (!mm)
612                 goto out_free;
613
614         ret = -EIO;
615  
616         if (file->private_data != (void*)((long)current->self_exec_id))
617                 goto out_put;
618
619         ret = 0;
620  
621         while (count > 0) {
622                 int this_len, retval;
623
624                 this_len = (count > PAGE_SIZE) ? PAGE_SIZE : count;
625                 retval = access_process_vm(task, src, page, this_len, 0);
626                 if (!retval || !MAY_PTRACE(task) || !may_ptrace_attach(task)) {
627                         if (!ret)
628                                 ret = -EIO;
629                         break;
630                 }
631
632                 if (copy_to_user(buf, page, retval)) {
633                         ret = -EFAULT;
634                         break;
635                 }
636  
637                 ret += retval;
638                 src += retval;
639                 buf += retval;
640                 count -= retval;
641         }
642         *ppos = src;
643
644 out_put:
645         mmput(mm);
646 out_free:
647         free_page((unsigned long) page);
648 out:
649         return ret;
650 }
651
652 #define mem_write NULL
653
654 #ifndef mem_write
655 /* This is a security hazard */
656 static ssize_t mem_write(struct file * file, const char * buf,
657                          size_t count, loff_t *ppos)
658 {
659         int copied = 0;
660         char *page;
661         struct task_struct *task = proc_task(file->f_dentry->d_inode);
662         unsigned long dst = *ppos;
663
664         if (!MAY_PTRACE(task) || !may_ptrace_attach(task))
665                 return -ESRCH;
666
667         page = (char *)__get_free_page(GFP_USER);
668         if (!page)
669                 return -ENOMEM;
670
671         while (count > 0) {
672                 int this_len, retval;
673
674                 this_len = (count > PAGE_SIZE) ? PAGE_SIZE : count;
675                 if (copy_from_user(page, buf, this_len)) {
676                         copied = -EFAULT;
677                         break;
678                 }
679                 retval = access_process_vm(task, dst, page, this_len, 1);
680                 if (!retval) {
681                         if (!copied)
682                                 copied = -EIO;
683                         break;
684                 }
685                 copied += retval;
686                 buf += retval;
687                 dst += retval;
688                 count -= retval;                        
689         }
690         *ppos = dst;
691         free_page((unsigned long) page);
692         return copied;
693 }
694 #endif
695
696 static loff_t mem_lseek(struct file * file, loff_t offset, int orig)
697 {
698         switch (orig) {
699         case 0:
700                 file->f_pos = offset;
701                 break;
702         case 1:
703                 file->f_pos += offset;
704                 break;
705         default:
706                 return -EINVAL;
707         }
708         force_successful_syscall_return();
709         return file->f_pos;
710 }
711
712 static struct file_operations proc_mem_operations = {
713         .llseek         = mem_lseek,
714         .read           = mem_read,
715         .write          = mem_write,
716         .open           = mem_open,
717 };
718
719 static ssize_t oom_adjust_read(struct file *file, char __user *buf,
720                                 size_t count, loff_t *ppos)
721 {
722         struct task_struct *task = proc_task(file->f_dentry->d_inode);
723         char buffer[8];
724         size_t len;
725         int oom_adjust = task->oomkilladj;
726         loff_t __ppos = *ppos;
727
728         len = sprintf(buffer, "%i\n", oom_adjust);
729         if (__ppos >= len)
730                 return 0;
731         if (count > len-__ppos)
732                 count = len-__ppos;
733         if (copy_to_user(buf, buffer + __ppos, count))
734                 return -EFAULT;
735         *ppos = __ppos + count;
736         return count;
737 }
738
739 static ssize_t oom_adjust_write(struct file *file, const char __user *buf,
740                                 size_t count, loff_t *ppos)
741 {
742         struct task_struct *task = proc_task(file->f_dentry->d_inode);
743         char buffer[8], *end;
744         int oom_adjust;
745
746         if (!capable(CAP_SYS_RESOURCE))
747                 return -EPERM;
748         memset(buffer, 0, 8);
749         if (count > 6)
750                 count = 6;
751         if (copy_from_user(buffer, buf, count))
752                 return -EFAULT;
753         oom_adjust = simple_strtol(buffer, &end, 0);
754         if ((oom_adjust < -16 || oom_adjust > 15) && oom_adjust != OOM_DISABLE)
755                 return -EINVAL;
756         if (*end == '\n')
757                 end++;
758         task->oomkilladj = oom_adjust;
759         if (end - buffer == 0)
760                 return -EIO;
761         return end - buffer;
762 }
763
764 static struct file_operations proc_oom_adjust_operations = {
765         .read           = oom_adjust_read,
766         .write          = oom_adjust_write,
767 };
768
769 static struct inode_operations proc_mem_inode_operations = {
770         .permission     = proc_permission,
771 };
772
773 #ifdef CONFIG_AUDITSYSCALL
774 #define TMPBUFLEN 21
775 static ssize_t proc_loginuid_read(struct file * file, char __user * buf,
776                                   size_t count, loff_t *ppos)
777 {
778         struct inode * inode = file->f_dentry->d_inode;
779         struct task_struct *task = proc_task(inode);
780         ssize_t length;
781         char tmpbuf[TMPBUFLEN];
782
783         length = scnprintf(tmpbuf, TMPBUFLEN, "%u",
784                                 audit_get_loginuid(task->audit_context));
785         return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
786 }
787
788 static ssize_t proc_loginuid_write(struct file * file, const char __user * buf,
789                                    size_t count, loff_t *ppos)
790 {
791         struct inode * inode = file->f_dentry->d_inode;
792         char *page, *tmp;
793         ssize_t length;
794         struct task_struct *task = proc_task(inode);
795         uid_t loginuid;
796
797         if (!capable(CAP_AUDIT_CONTROL))
798                 return -EPERM;
799
800         if (current != task)
801                 return -EPERM;
802
803         if (count > PAGE_SIZE)
804                 count = PAGE_SIZE;
805
806         if (*ppos != 0) {
807                 /* No partial writes. */
808                 return -EINVAL;
809         }
810         page = (char*)__get_free_page(GFP_USER);
811         if (!page)
812                 return -ENOMEM;
813         length = -EFAULT;
814         if (copy_from_user(page, buf, count))
815                 goto out_free_page;
816
817         loginuid = simple_strtoul(page, &tmp, 10);
818         if (tmp == page) {
819                 length = -EINVAL;
820                 goto out_free_page;
821
822         }
823         length = audit_set_loginuid(task, loginuid);
824         if (likely(length == 0))
825                 length = count;
826
827 out_free_page:
828         free_page((unsigned long) page);
829         return length;
830 }
831
832 static struct file_operations proc_loginuid_operations = {
833         .read           = proc_loginuid_read,
834         .write          = proc_loginuid_write,
835 };
836 #endif
837
838 #ifdef CONFIG_SECCOMP
839 static ssize_t seccomp_read(struct file *file, char __user *buf,
840                             size_t count, loff_t *ppos)
841 {
842         struct task_struct *tsk = proc_task(file->f_dentry->d_inode);
843         char __buf[20];
844         loff_t __ppos = *ppos;
845         size_t len;
846
847         /* no need to print the trailing zero, so use only len */
848         len = sprintf(__buf, "%u\n", tsk->seccomp.mode);
849         if (__ppos >= len)
850                 return 0;
851         if (count > len - __ppos)
852                 count = len - __ppos;
853         if (copy_to_user(buf, __buf + __ppos, count))
854                 return -EFAULT;
855         *ppos = __ppos + count;
856         return count;
857 }
858
859 static ssize_t seccomp_write(struct file *file, const char __user *buf,
860                              size_t count, loff_t *ppos)
861 {
862         struct task_struct *tsk = proc_task(file->f_dentry->d_inode);
863         char __buf[20], *end;
864         unsigned int seccomp_mode;
865
866         /* can set it only once to be even more secure */
867         if (unlikely(tsk->seccomp.mode))
868                 return -EPERM;
869
870         memset(__buf, 0, sizeof(__buf));
871         count = min(count, sizeof(__buf) - 1);
872         if (copy_from_user(__buf, buf, count))
873                 return -EFAULT;
874         seccomp_mode = simple_strtoul(__buf, &end, 0);
875         if (*end == '\n')
876                 end++;
877         if (seccomp_mode && seccomp_mode <= NR_SECCOMP_MODES) {
878                 tsk->seccomp.mode = seccomp_mode;
879                 set_tsk_thread_flag(tsk, TIF_SECCOMP);
880         } else
881                 return -EINVAL;
882         if (unlikely(!(end - __buf)))
883                 return -EIO;
884         return end - __buf;
885 }
886
887 static struct file_operations proc_seccomp_operations = {
888         .read           = seccomp_read,
889         .write          = seccomp_write,
890 };
891 #endif /* CONFIG_SECCOMP */
892
893 static int proc_pid_follow_link(struct dentry *dentry, struct nameidata *nd)
894 {
895         struct inode *inode = dentry->d_inode;
896         int error = -EACCES;
897
898         /* We don't need a base pointer in the /proc filesystem */
899         path_release(nd);
900
901         if (current->fsuid != inode->i_uid && !capable(CAP_DAC_OVERRIDE))
902                 goto out;
903         error = proc_check_root(inode);
904         if (error)
905                 goto out;
906
907         error = PROC_I(inode)->op.proc_get_link(inode, &nd->dentry, &nd->mnt);
908         nd->last_type = LAST_BIND;
909 out:
910         return error;
911 }
912
913 static int do_proc_readlink(struct dentry *dentry, struct vfsmount *mnt,
914                             char __user *buffer, int buflen)
915 {
916         struct inode * inode;
917         char *tmp = (char*)__get_free_page(GFP_KERNEL), *path;
918         int len;
919
920         if (!tmp)
921                 return -ENOMEM;
922                 
923         inode = dentry->d_inode;
924         path = d_path(dentry, mnt, tmp, PAGE_SIZE);
925         len = PTR_ERR(path);
926         if (IS_ERR(path))
927                 goto out;
928         len = tmp + PAGE_SIZE - 1 - path;
929
930         if (len > buflen)
931                 len = buflen;
932         if (copy_to_user(buffer, path, len))
933                 len = -EFAULT;
934  out:
935         free_page((unsigned long)tmp);
936         return len;
937 }
938
939 static int proc_pid_readlink(struct dentry * dentry, char __user * buffer, int buflen)
940 {
941         int error = -EACCES;
942         struct inode *inode = dentry->d_inode;
943         struct dentry *de;
944         struct vfsmount *mnt = NULL;
945
946         lock_kernel();
947
948         if (current->fsuid != inode->i_uid && !capable(CAP_DAC_OVERRIDE))
949                 goto out;
950         error = proc_check_root(inode);
951         if (error)
952                 goto out;
953
954         error = PROC_I(inode)->op.proc_get_link(inode, &de, &mnt);
955         if (error)
956                 goto out;
957
958         error = do_proc_readlink(de, mnt, buffer, buflen);
959         dput(de);
960         mntput(mnt);
961 out:
962         unlock_kernel();
963         return error;
964 }
965
966 static struct inode_operations proc_pid_link_inode_operations = {
967         .readlink       = proc_pid_readlink,
968         .follow_link    = proc_pid_follow_link
969 };
970
971 #define NUMBUF 10
972
973 static int proc_readfd(struct file * filp, void * dirent, filldir_t filldir)
974 {
975         struct inode *inode = filp->f_dentry->d_inode;
976         struct task_struct *p = proc_task(inode);
977         unsigned int fd, tid, ino;
978         int retval;
979         char buf[NUMBUF];
980         struct files_struct * files;
981
982         retval = -ENOENT;
983         if (!pid_alive(p))
984                 goto out;
985         retval = 0;
986         tid = p->pid;
987
988         fd = filp->f_pos;
989         switch (fd) {
990                 case 0:
991                         if (filldir(dirent, ".", 1, 0, inode->i_ino, DT_DIR) < 0)
992                                 goto out;
993                         filp->f_pos++;
994                 case 1:
995                         ino = fake_ino(tid, PROC_TID_INO);
996                         if (filldir(dirent, "..", 2, 1, ino, DT_DIR) < 0)
997                                 goto out;
998                         filp->f_pos++;
999                 default:
1000                         files = get_files_struct(p);
1001                         if (!files)
1002                                 goto out;
1003                         spin_lock(&files->file_lock);
1004                         for (fd = filp->f_pos-2;
1005                              fd < files->max_fds;
1006                              fd++, filp->f_pos++) {
1007                                 unsigned int i,j;
1008
1009                                 if (!fcheck_files(files, fd))
1010                                         continue;
1011                                 spin_unlock(&files->file_lock);
1012
1013                                 j = NUMBUF;
1014                                 i = fd;
1015                                 do {
1016                                         j--;
1017                                         buf[j] = '0' + (i % 10);
1018                                         i /= 10;
1019                                 } while (i);
1020
1021                                 ino = fake_ino(tid, PROC_TID_FD_DIR + fd);
1022                                 if (filldir(dirent, buf+j, NUMBUF-j, fd+2, ino, DT_LNK) < 0) {
1023                                         spin_lock(&files->file_lock);
1024                                         break;
1025                                 }
1026                                 spin_lock(&files->file_lock);
1027                         }
1028                         spin_unlock(&files->file_lock);
1029                         put_files_struct(files);
1030         }
1031 out:
1032         return retval;
1033 }
1034
1035 static int proc_pident_readdir(struct file *filp,
1036                 void *dirent, filldir_t filldir,
1037                 struct pid_entry *ents, unsigned int nents)
1038 {
1039         int i;
1040         int pid;
1041         struct dentry *dentry = filp->f_dentry;
1042         struct inode *inode = dentry->d_inode;
1043         struct pid_entry *p;
1044         ino_t ino;
1045         int ret;
1046
1047         ret = -ENOENT;
1048         if (!pid_alive(proc_task(inode)))
1049                 goto out;
1050
1051         ret = 0;
1052         pid = proc_task(inode)->pid;
1053         i = filp->f_pos;
1054         switch (i) {
1055         case 0:
1056                 ino = inode->i_ino;
1057                 if (filldir(dirent, ".", 1, i, ino, DT_DIR) < 0)
1058                         goto out;
1059                 i++;
1060                 filp->f_pos++;
1061                 /* fall through */
1062         case 1:
1063                 ino = parent_ino(dentry);
1064                 if (filldir(dirent, "..", 2, i, ino, DT_DIR) < 0)
1065                         goto out;
1066                 i++;
1067                 filp->f_pos++;
1068                 /* fall through */
1069         default:
1070                 i -= 2;
1071                 if (i >= nents) {
1072                         ret = 1;
1073                         goto out;
1074                 }
1075                 p = ents + i;
1076                 while (p->name) {
1077                         if (filldir(dirent, p->name, p->len, filp->f_pos,
1078                                     fake_ino(pid, p->type), p->mode >> 12) < 0)
1079                                 goto out;
1080                         filp->f_pos++;
1081                         p++;
1082                 }
1083         }
1084
1085         ret = 1;
1086 out:
1087         return ret;
1088 }
1089
1090 static int proc_tgid_base_readdir(struct file * filp,
1091                              void * dirent, filldir_t filldir)
1092 {
1093         return proc_pident_readdir(filp,dirent,filldir,
1094                                    tgid_base_stuff,ARRAY_SIZE(tgid_base_stuff));
1095 }
1096
1097 static int proc_tid_base_readdir(struct file * filp,
1098                              void * dirent, filldir_t filldir)
1099 {
1100         return proc_pident_readdir(filp,dirent,filldir,
1101                                    tid_base_stuff,ARRAY_SIZE(tid_base_stuff));
1102 }
1103
1104 /* building an inode */
1105
1106 static int task_dumpable(struct task_struct *task)
1107 {
1108         int dumpable = 0;
1109         struct mm_struct *mm;
1110
1111         task_lock(task);
1112         mm = task->mm;
1113         if (mm)
1114                 dumpable = mm->dumpable;
1115         task_unlock(task);
1116         return dumpable;
1117 }
1118
1119
1120 static struct inode *proc_pid_make_inode(struct super_block * sb, struct task_struct *task, int ino)
1121 {
1122         struct inode * inode;
1123         struct proc_inode *ei;
1124
1125         /* We need a new inode */
1126         
1127         inode = new_inode(sb);
1128         if (!inode)
1129                 goto out;
1130
1131         /* Common stuff */
1132         ei = PROC_I(inode);
1133         ei->task = NULL;
1134         inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
1135         inode->i_ino = fake_ino(task->pid, ino);
1136
1137         if (!pid_alive(task))
1138                 goto out_unlock;
1139
1140         /*
1141          * grab the reference to task.
1142          */
1143         get_task_struct(task);
1144         ei->task = task;
1145         ei->type = ino;
1146         inode->i_uid = 0;
1147         inode->i_gid = 0;
1148         if (ino == PROC_TGID_INO || ino == PROC_TID_INO || task_dumpable(task)) {
1149                 inode->i_uid = task->euid;
1150                 inode->i_gid = task->egid;
1151         }
1152         security_task_to_inode(task, inode);
1153
1154 out:
1155         return inode;
1156
1157 out_unlock:
1158         ei->pde = NULL;
1159         iput(inode);
1160         return NULL;
1161 }
1162
1163 /* dentry stuff */
1164
1165 /*
1166  *      Exceptional case: normally we are not allowed to unhash a busy
1167  * directory. In this case, however, we can do it - no aliasing problems
1168  * due to the way we treat inodes.
1169  *
1170  * Rewrite the inode's ownerships here because the owning task may have
1171  * performed a setuid(), etc.
1172  */
1173 static int pid_revalidate(struct dentry *dentry, struct nameidata *nd)
1174 {
1175         struct inode *inode = dentry->d_inode;
1176         struct task_struct *task = proc_task(inode);
1177         if (pid_alive(task)) {
1178                 if (proc_type(inode) == PROC_TGID_INO || proc_type(inode) == PROC_TID_INO || task_dumpable(task)) {
1179                         inode->i_uid = task->euid;
1180                         inode->i_gid = task->egid;
1181                 } else {
1182                         inode->i_uid = 0;
1183                         inode->i_gid = 0;
1184                 }
1185                 security_task_to_inode(task, inode);
1186                 return 1;
1187         }
1188         d_drop(dentry);
1189         return 0;
1190 }
1191
1192 static int tid_fd_revalidate(struct dentry *dentry, struct nameidata *nd)
1193 {
1194         struct inode *inode = dentry->d_inode;
1195         struct task_struct *task = proc_task(inode);
1196         int fd = proc_type(inode) - PROC_TID_FD_DIR;
1197         struct files_struct *files;
1198
1199         files = get_files_struct(task);
1200         if (files) {
1201                 spin_lock(&files->file_lock);
1202                 if (fcheck_files(files, fd)) {
1203                         spin_unlock(&files->file_lock);
1204                         put_files_struct(files);
1205                         if (task_dumpable(task)) {
1206                                 inode->i_uid = task->euid;
1207                                 inode->i_gid = task->egid;
1208                         } else {
1209                                 inode->i_uid = 0;
1210                                 inode->i_gid = 0;
1211                         }
1212                         security_task_to_inode(task, inode);
1213                         return 1;
1214                 }
1215                 spin_unlock(&files->file_lock);
1216                 put_files_struct(files);
1217         }
1218         d_drop(dentry);
1219         return 0;
1220 }
1221
1222 static void pid_base_iput(struct dentry *dentry, struct inode *inode)
1223 {
1224         struct task_struct *task = proc_task(inode);
1225         spin_lock(&task->proc_lock);
1226         if (task->proc_dentry == dentry)
1227                 task->proc_dentry = NULL;
1228         spin_unlock(&task->proc_lock);
1229         iput(inode);
1230 }
1231
1232 static int pid_delete_dentry(struct dentry * dentry)
1233 {
1234         /* Is the task we represent dead?
1235          * If so, then don't put the dentry on the lru list,
1236          * kill it immediately.
1237          */
1238         return !pid_alive(proc_task(dentry->d_inode));
1239 }
1240
1241 static struct dentry_operations tid_fd_dentry_operations =
1242 {
1243         .d_revalidate   = tid_fd_revalidate,
1244         .d_delete       = pid_delete_dentry,
1245 };
1246
1247 static struct dentry_operations pid_dentry_operations =
1248 {
1249         .d_revalidate   = pid_revalidate,
1250         .d_delete       = pid_delete_dentry,
1251 };
1252
1253 static struct dentry_operations pid_base_dentry_operations =
1254 {
1255         .d_revalidate   = pid_revalidate,
1256         .d_iput         = pid_base_iput,
1257         .d_delete       = pid_delete_dentry,
1258 };
1259
1260 /* Lookups */
1261
1262 static unsigned name_to_int(struct dentry *dentry)
1263 {
1264         const char *name = dentry->d_name.name;
1265         int len = dentry->d_name.len;
1266         unsigned n = 0;
1267
1268         if (len > 1 && *name == '0')
1269                 goto out;
1270         while (len-- > 0) {
1271                 unsigned c = *name++ - '0';
1272                 if (c > 9)
1273                         goto out;
1274                 if (n >= (~0U-9)/10)
1275                         goto out;
1276                 n *= 10;
1277                 n += c;
1278         }
1279         return n;
1280 out:
1281         return ~0U;
1282 }
1283
1284 /* SMP-safe */
1285 static struct dentry *proc_lookupfd(struct inode * dir, struct dentry * dentry, struct nameidata *nd)
1286 {
1287         struct task_struct *task = proc_task(dir);
1288         unsigned fd = name_to_int(dentry);
1289         struct file * file;
1290         struct files_struct * files;
1291         struct inode *inode;
1292         struct proc_inode *ei;
1293
1294         if (fd == ~0U)
1295                 goto out;
1296         if (!pid_alive(task))
1297                 goto out;
1298
1299         inode = proc_pid_make_inode(dir->i_sb, task, PROC_TID_FD_DIR+fd);
1300         if (!inode)
1301                 goto out;
1302         ei = PROC_I(inode);
1303         files = get_files_struct(task);
1304         if (!files)
1305                 goto out_unlock;
1306         inode->i_mode = S_IFLNK;
1307         spin_lock(&files->file_lock);
1308         file = fcheck_files(files, fd);
1309         if (!file)
1310                 goto out_unlock2;
1311         if (file->f_mode & 1)
1312                 inode->i_mode |= S_IRUSR | S_IXUSR;
1313         if (file->f_mode & 2)
1314                 inode->i_mode |= S_IWUSR | S_IXUSR;
1315         spin_unlock(&files->file_lock);
1316         put_files_struct(files);
1317         inode->i_op = &proc_pid_link_inode_operations;
1318         inode->i_size = 64;
1319         ei->op.proc_get_link = proc_fd_link;
1320         dentry->d_op = &tid_fd_dentry_operations;
1321         d_add(dentry, inode);
1322         return NULL;
1323
1324 out_unlock2:
1325         spin_unlock(&files->file_lock);
1326         put_files_struct(files);
1327 out_unlock:
1328         iput(inode);
1329 out:
1330         return ERR_PTR(-ENOENT);
1331 }
1332
1333 static int proc_task_readdir(struct file * filp, void * dirent, filldir_t filldir);
1334 static struct dentry *proc_task_lookup(struct inode *dir, struct dentry * dentry, struct nameidata *nd);
1335
1336 static struct file_operations proc_fd_operations = {
1337         .read           = generic_read_dir,
1338         .readdir        = proc_readfd,
1339 };
1340
1341 static struct file_operations proc_task_operations = {
1342         .read           = generic_read_dir,
1343         .readdir        = proc_task_readdir,
1344 };
1345
1346 /*
1347  * proc directories can do almost nothing..
1348  */
1349 static struct inode_operations proc_fd_inode_operations = {
1350         .lookup         = proc_lookupfd,
1351         .permission     = proc_permission,
1352 };
1353
1354 static struct inode_operations proc_task_inode_operations = {
1355         .lookup         = proc_task_lookup,
1356         .permission     = proc_permission,
1357 };
1358
1359 #ifdef CONFIG_SECURITY
1360 static ssize_t proc_pid_attr_read(struct file * file, char __user * buf,
1361                                   size_t count, loff_t *ppos)
1362 {
1363         struct inode * inode = file->f_dentry->d_inode;
1364         unsigned long page;
1365         ssize_t length;
1366         struct task_struct *task = proc_task(inode);
1367
1368         if (count > PAGE_SIZE)
1369                 count = PAGE_SIZE;
1370         if (!(page = __get_free_page(GFP_KERNEL)))
1371                 return -ENOMEM;
1372
1373         length = security_getprocattr(task, 
1374                                       (char*)file->f_dentry->d_name.name, 
1375                                       (void*)page, count);
1376         if (length >= 0)
1377                 length = simple_read_from_buffer(buf, count, ppos, (char *)page, length);
1378         free_page(page);
1379         return length;
1380 }
1381
1382 static ssize_t proc_pid_attr_write(struct file * file, const char __user * buf,
1383                                    size_t count, loff_t *ppos)
1384
1385         struct inode * inode = file->f_dentry->d_inode;
1386         char *page; 
1387         ssize_t length; 
1388         struct task_struct *task = proc_task(inode); 
1389
1390         if (count > PAGE_SIZE) 
1391                 count = PAGE_SIZE; 
1392         if (*ppos != 0) {
1393                 /* No partial writes. */
1394                 return -EINVAL;
1395         }
1396         page = (char*)__get_free_page(GFP_USER); 
1397         if (!page) 
1398                 return -ENOMEM;
1399         length = -EFAULT; 
1400         if (copy_from_user(page, buf, count)) 
1401                 goto out;
1402
1403         length = security_setprocattr(task, 
1404                                       (char*)file->f_dentry->d_name.name, 
1405                                       (void*)page, count);
1406 out:
1407         free_page((unsigned long) page);
1408         return length;
1409
1410
1411 static struct file_operations proc_pid_attr_operations = {
1412         .read           = proc_pid_attr_read,
1413         .write          = proc_pid_attr_write,
1414 };
1415
1416 static struct file_operations proc_tid_attr_operations;
1417 static struct inode_operations proc_tid_attr_inode_operations;
1418 static struct file_operations proc_tgid_attr_operations;
1419 static struct inode_operations proc_tgid_attr_inode_operations;
1420 #endif
1421
1422 static int get_tid_list(int index, unsigned int *tids, struct inode *dir);
1423
1424 /* SMP-safe */
1425 static struct dentry *proc_pident_lookup(struct inode *dir, 
1426                                          struct dentry *dentry,
1427                                          struct pid_entry *ents)
1428 {
1429         struct inode *inode;
1430         int error;
1431         struct task_struct *task = proc_task(dir);
1432         struct pid_entry *p;
1433         struct proc_inode *ei;
1434
1435         error = -ENOENT;
1436         inode = NULL;
1437
1438         if (!pid_alive(task))
1439                 goto out;
1440
1441         for (p = ents; p->name; p++) {
1442                 if (p->len != dentry->d_name.len)
1443                         continue;
1444                 if (!memcmp(dentry->d_name.name, p->name, p->len))
1445                         break;
1446         }
1447         if (!p->name)
1448                 goto out;
1449
1450         error = -EINVAL;
1451         inode = proc_pid_make_inode(dir->i_sb, task, p->type);
1452         if (!inode)
1453                 goto out;
1454
1455         ei = PROC_I(inode);
1456         inode->i_mode = p->mode;
1457         /*
1458          * Yes, it does not scale. And it should not. Don't add
1459          * new entries into /proc/<tgid>/ without very good reasons.
1460          */
1461         switch(p->type) {
1462                 case PROC_TGID_TASK:
1463                         inode->i_nlink = 2 + get_tid_list(2, NULL, dir);
1464                         inode->i_op = &proc_task_inode_operations;
1465                         inode->i_fop = &proc_task_operations;
1466                         break;
1467                 case PROC_TID_FD:
1468                 case PROC_TGID_FD:
1469                         inode->i_nlink = 2;
1470                         inode->i_op = &proc_fd_inode_operations;
1471                         inode->i_fop = &proc_fd_operations;
1472                         break;
1473                 case PROC_TID_EXE:
1474                 case PROC_TGID_EXE:
1475                         inode->i_op = &proc_pid_link_inode_operations;
1476                         ei->op.proc_get_link = proc_exe_link;
1477                         break;
1478                 case PROC_TID_CWD:
1479                 case PROC_TGID_CWD:
1480                         inode->i_op = &proc_pid_link_inode_operations;
1481                         ei->op.proc_get_link = proc_cwd_link;
1482                         break;
1483                 case PROC_TID_ROOT:
1484                 case PROC_TGID_ROOT:
1485                         inode->i_op = &proc_pid_link_inode_operations;
1486                         ei->op.proc_get_link = proc_root_link;
1487                         break;
1488                 case PROC_TID_ENVIRON:
1489                 case PROC_TGID_ENVIRON:
1490                         inode->i_fop = &proc_info_file_operations;
1491                         ei->op.proc_read = proc_pid_environ;
1492                         break;
1493                 case PROC_TID_AUXV:
1494                 case PROC_TGID_AUXV:
1495                         inode->i_fop = &proc_info_file_operations;
1496                         ei->op.proc_read = proc_pid_auxv;
1497                         break;
1498                 case PROC_TID_STATUS:
1499                 case PROC_TGID_STATUS:
1500                         inode->i_fop = &proc_info_file_operations;
1501                         ei->op.proc_read = proc_pid_status;
1502                         break;
1503                 case PROC_TID_STAT:
1504                         inode->i_fop = &proc_info_file_operations;
1505                         ei->op.proc_read = proc_tid_stat;
1506                         break;
1507                 case PROC_TGID_STAT:
1508                         inode->i_fop = &proc_info_file_operations;
1509                         ei->op.proc_read = proc_tgid_stat;
1510                         break;
1511                 case PROC_TID_CMDLINE:
1512                 case PROC_TGID_CMDLINE:
1513                         inode->i_fop = &proc_info_file_operations;
1514                         ei->op.proc_read = proc_pid_cmdline;
1515                         break;
1516                 case PROC_TID_STATM:
1517                 case PROC_TGID_STATM:
1518                         inode->i_fop = &proc_info_file_operations;
1519                         ei->op.proc_read = proc_pid_statm;
1520                         break;
1521                 case PROC_TID_MAPS:
1522                 case PROC_TGID_MAPS:
1523                         inode->i_fop = &proc_maps_operations;
1524                         break;
1525                 case PROC_TID_MEM:
1526                 case PROC_TGID_MEM:
1527                         inode->i_op = &proc_mem_inode_operations;
1528                         inode->i_fop = &proc_mem_operations;
1529                         break;
1530 #ifdef CONFIG_SECCOMP
1531                 case PROC_TID_SECCOMP:
1532                 case PROC_TGID_SECCOMP:
1533                         inode->i_fop = &proc_seccomp_operations;
1534                         break;
1535 #endif /* CONFIG_SECCOMP */
1536                 case PROC_TID_MOUNTS:
1537                 case PROC_TGID_MOUNTS:
1538                         inode->i_fop = &proc_mounts_operations;
1539                         break;
1540 #ifdef CONFIG_SECURITY
1541                 case PROC_TID_ATTR:
1542                         inode->i_nlink = 2;
1543                         inode->i_op = &proc_tid_attr_inode_operations;
1544                         inode->i_fop = &proc_tid_attr_operations;
1545                         break;
1546                 case PROC_TGID_ATTR:
1547                         inode->i_nlink = 2;
1548                         inode->i_op = &proc_tgid_attr_inode_operations;
1549                         inode->i_fop = &proc_tgid_attr_operations;
1550                         break;
1551                 case PROC_TID_ATTR_CURRENT:
1552                 case PROC_TGID_ATTR_CURRENT:
1553                 case PROC_TID_ATTR_PREV:
1554                 case PROC_TGID_ATTR_PREV:
1555                 case PROC_TID_ATTR_EXEC:
1556                 case PROC_TGID_ATTR_EXEC:
1557                 case PROC_TID_ATTR_FSCREATE:
1558                 case PROC_TGID_ATTR_FSCREATE:
1559                         inode->i_fop = &proc_pid_attr_operations;
1560                         break;
1561 #endif
1562 #ifdef CONFIG_KALLSYMS
1563                 case PROC_TID_WCHAN:
1564                 case PROC_TGID_WCHAN:
1565                         inode->i_fop = &proc_info_file_operations;
1566                         ei->op.proc_read = proc_pid_wchan;
1567                         break;
1568 #endif
1569 #ifdef CONFIG_SCHEDSTATS
1570                 case PROC_TID_SCHEDSTAT:
1571                 case PROC_TGID_SCHEDSTAT:
1572                         inode->i_fop = &proc_info_file_operations;
1573                         ei->op.proc_read = proc_pid_schedstat;
1574                         break;
1575 #endif
1576 #ifdef CONFIG_CPUSETS
1577                 case PROC_TID_CPUSET:
1578                 case PROC_TGID_CPUSET:
1579                         inode->i_fop = &proc_cpuset_operations;
1580                         break;
1581 #endif
1582                 case PROC_TID_OOM_SCORE:
1583                 case PROC_TGID_OOM_SCORE:
1584                         inode->i_fop = &proc_info_file_operations;
1585                         ei->op.proc_read = proc_oom_score;
1586                         break;
1587                 case PROC_TID_OOM_ADJUST:
1588                 case PROC_TGID_OOM_ADJUST:
1589                         inode->i_fop = &proc_oom_adjust_operations;
1590                         break;
1591 #ifdef CONFIG_AUDITSYSCALL
1592                 case PROC_TID_LOGINUID:
1593                 case PROC_TGID_LOGINUID:
1594                         inode->i_fop = &proc_loginuid_operations;
1595                         break;
1596 #endif
1597                 default:
1598                         printk("procfs: impossible type (%d)",p->type);
1599                         iput(inode);
1600                         return ERR_PTR(-EINVAL);
1601         }
1602         dentry->d_op = &pid_dentry_operations;
1603         d_add(dentry, inode);
1604         return NULL;
1605
1606 out:
1607         return ERR_PTR(error);
1608 }
1609
1610 static struct dentry *proc_tgid_base_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd){
1611         return proc_pident_lookup(dir, dentry, tgid_base_stuff);
1612 }
1613
1614 static struct dentry *proc_tid_base_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd){
1615         return proc_pident_lookup(dir, dentry, tid_base_stuff);
1616 }
1617
1618 static struct file_operations proc_tgid_base_operations = {
1619         .read           = generic_read_dir,
1620         .readdir        = proc_tgid_base_readdir,
1621 };
1622
1623 static struct file_operations proc_tid_base_operations = {
1624         .read           = generic_read_dir,
1625         .readdir        = proc_tid_base_readdir,
1626 };
1627
1628 static struct inode_operations proc_tgid_base_inode_operations = {
1629         .lookup         = proc_tgid_base_lookup,
1630 };
1631
1632 static struct inode_operations proc_tid_base_inode_operations = {
1633         .lookup         = proc_tid_base_lookup,
1634 };
1635
1636 #ifdef CONFIG_SECURITY
1637 static int proc_tgid_attr_readdir(struct file * filp,
1638                              void * dirent, filldir_t filldir)
1639 {
1640         return proc_pident_readdir(filp,dirent,filldir,
1641                                    tgid_attr_stuff,ARRAY_SIZE(tgid_attr_stuff));
1642 }
1643
1644 static int proc_tid_attr_readdir(struct file * filp,
1645                              void * dirent, filldir_t filldir)
1646 {
1647         return proc_pident_readdir(filp,dirent,filldir,
1648                                    tid_attr_stuff,ARRAY_SIZE(tid_attr_stuff));
1649 }
1650
1651 static struct file_operations proc_tgid_attr_operations = {
1652         .read           = generic_read_dir,
1653         .readdir        = proc_tgid_attr_readdir,
1654 };
1655
1656 static struct file_operations proc_tid_attr_operations = {
1657         .read           = generic_read_dir,
1658         .readdir        = proc_tid_attr_readdir,
1659 };
1660
1661 static struct dentry *proc_tgid_attr_lookup(struct inode *dir,
1662                                 struct dentry *dentry, struct nameidata *nd)
1663 {
1664         return proc_pident_lookup(dir, dentry, tgid_attr_stuff);
1665 }
1666
1667 static struct dentry *proc_tid_attr_lookup(struct inode *dir,
1668                                 struct dentry *dentry, struct nameidata *nd)
1669 {
1670         return proc_pident_lookup(dir, dentry, tid_attr_stuff);
1671 }
1672
1673 static struct inode_operations proc_tgid_attr_inode_operations = {
1674         .lookup         = proc_tgid_attr_lookup,
1675 };
1676
1677 static struct inode_operations proc_tid_attr_inode_operations = {
1678         .lookup         = proc_tid_attr_lookup,
1679 };
1680 #endif
1681
1682 /*
1683  * /proc/self:
1684  */
1685 static int proc_self_readlink(struct dentry *dentry, char __user *buffer,
1686                               int buflen)
1687 {
1688         char tmp[30];
1689         sprintf(tmp, "%d", current->tgid);
1690         return vfs_readlink(dentry,buffer,buflen,tmp);
1691 }
1692
1693 static int proc_self_follow_link(struct dentry *dentry, struct nameidata *nd)
1694 {
1695         char tmp[30];
1696         sprintf(tmp, "%d", current->tgid);
1697         return vfs_follow_link(nd,tmp);
1698 }       
1699
1700 static struct inode_operations proc_self_inode_operations = {
1701         .readlink       = proc_self_readlink,
1702         .follow_link    = proc_self_follow_link,
1703 };
1704
1705 /**
1706  * proc_pid_unhash -  Unhash /proc/@pid entry from the dcache.
1707  * @p: task that should be flushed.
1708  *
1709  * Drops the /proc/@pid dcache entry from the hash chains.
1710  *
1711  * Dropping /proc/@pid entries and detach_pid must be synchroneous,
1712  * otherwise e.g. /proc/@pid/exe might point to the wrong executable,
1713  * if the pid value is immediately reused. This is enforced by
1714  * - caller must acquire spin_lock(p->proc_lock)
1715  * - must be called before detach_pid()
1716  * - proc_pid_lookup acquires proc_lock, and checks that
1717  *   the target is not dead by looking at the attach count
1718  *   of PIDTYPE_PID.
1719  */
1720
1721 struct dentry *proc_pid_unhash(struct task_struct *p)
1722 {
1723         struct dentry *proc_dentry;
1724
1725         proc_dentry = p->proc_dentry;
1726         if (proc_dentry != NULL) {
1727
1728                 spin_lock(&dcache_lock);
1729                 spin_lock(&proc_dentry->d_lock);
1730                 if (!d_unhashed(proc_dentry)) {
1731                         dget_locked(proc_dentry);
1732                         __d_drop(proc_dentry);
1733                         spin_unlock(&proc_dentry->d_lock);
1734                 } else {
1735                         spin_unlock(&proc_dentry->d_lock);
1736                         proc_dentry = NULL;
1737                 }
1738                 spin_unlock(&dcache_lock);
1739         }
1740         return proc_dentry;
1741 }
1742
1743 /**
1744  * proc_pid_flush - recover memory used by stale /proc/@pid/x entries
1745  * @proc_dentry: directoy to prune.
1746  *
1747  * Shrink the /proc directory that was used by the just killed thread.
1748  */
1749         
1750 void proc_pid_flush(struct dentry *proc_dentry)
1751 {
1752         might_sleep();
1753         if(proc_dentry != NULL) {
1754                 shrink_dcache_parent(proc_dentry);
1755                 dput(proc_dentry);
1756         }
1757 }
1758
1759 /* SMP-safe */
1760 struct dentry *proc_pid_lookup(struct inode *dir, struct dentry * dentry, struct nameidata *nd)
1761 {
1762         struct task_struct *task;
1763         struct inode *inode;
1764         struct proc_inode *ei;
1765         unsigned tgid;
1766         int died;
1767
1768         if (dentry->d_name.len == 4 && !memcmp(dentry->d_name.name,"self",4)) {
1769                 inode = new_inode(dir->i_sb);
1770                 if (!inode)
1771                         return ERR_PTR(-ENOMEM);
1772                 ei = PROC_I(inode);
1773                 inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
1774                 inode->i_ino = fake_ino(0, PROC_TGID_INO);
1775                 ei->pde = NULL;
1776                 inode->i_mode = S_IFLNK|S_IRWXUGO;
1777                 inode->i_uid = inode->i_gid = 0;
1778                 inode->i_size = 64;
1779                 inode->i_op = &proc_self_inode_operations;
1780                 d_add(dentry, inode);
1781                 return NULL;
1782         }
1783         tgid = name_to_int(dentry);
1784         if (tgid == ~0U)
1785                 goto out;
1786
1787         read_lock(&tasklist_lock);
1788         task = find_task_by_pid(tgid);
1789         if (task)
1790                 get_task_struct(task);
1791         read_unlock(&tasklist_lock);
1792         if (!task)
1793                 goto out;
1794
1795         inode = proc_pid_make_inode(dir->i_sb, task, PROC_TGID_INO);
1796
1797
1798         if (!inode) {
1799                 put_task_struct(task);
1800                 goto out;
1801         }
1802         inode->i_mode = S_IFDIR|S_IRUGO|S_IXUGO;
1803         inode->i_op = &proc_tgid_base_inode_operations;
1804         inode->i_fop = &proc_tgid_base_operations;
1805         inode->i_flags|=S_IMMUTABLE;
1806 #ifdef CONFIG_SECURITY
1807         inode->i_nlink = 5;
1808 #else
1809         inode->i_nlink = 4;
1810 #endif
1811
1812         dentry->d_op = &pid_base_dentry_operations;
1813
1814         died = 0;
1815         d_add(dentry, inode);
1816         spin_lock(&task->proc_lock);
1817         task->proc_dentry = dentry;
1818         if (!pid_alive(task)) {
1819                 dentry = proc_pid_unhash(task);
1820                 died = 1;
1821         }
1822         spin_unlock(&task->proc_lock);
1823
1824         put_task_struct(task);
1825         if (died) {
1826                 proc_pid_flush(dentry);
1827                 goto out;
1828         }
1829         return NULL;
1830 out:
1831         return ERR_PTR(-ENOENT);
1832 }
1833
1834 /* SMP-safe */
1835 static struct dentry *proc_task_lookup(struct inode *dir, struct dentry * dentry, struct nameidata *nd)
1836 {
1837         struct task_struct *task;
1838         struct task_struct *leader = proc_task(dir);
1839         struct inode *inode;
1840         unsigned tid;
1841
1842         tid = name_to_int(dentry);
1843         if (tid == ~0U)
1844                 goto out;
1845
1846         read_lock(&tasklist_lock);
1847         task = find_task_by_pid(tid);
1848         if (task)
1849                 get_task_struct(task);
1850         read_unlock(&tasklist_lock);
1851         if (!task)
1852                 goto out;
1853         if (leader->tgid != task->tgid)
1854                 goto out_drop_task;
1855
1856         inode = proc_pid_make_inode(dir->i_sb, task, PROC_TID_INO);
1857
1858
1859         if (!inode)
1860                 goto out_drop_task;
1861         inode->i_mode = S_IFDIR|S_IRUGO|S_IXUGO;
1862         inode->i_op = &proc_tid_base_inode_operations;
1863         inode->i_fop = &proc_tid_base_operations;
1864         inode->i_flags|=S_IMMUTABLE;
1865 #ifdef CONFIG_SECURITY
1866         inode->i_nlink = 4;
1867 #else
1868         inode->i_nlink = 3;
1869 #endif
1870
1871         dentry->d_op = &pid_base_dentry_operations;
1872
1873         d_add(dentry, inode);
1874
1875         put_task_struct(task);
1876         return NULL;
1877 out_drop_task:
1878         put_task_struct(task);
1879 out:
1880         return ERR_PTR(-ENOENT);
1881 }
1882
1883 #define PROC_NUMBUF 10
1884 #define PROC_MAXPIDS 20
1885
1886 /*
1887  * Get a few tgid's to return for filldir - we need to hold the
1888  * tasklist lock while doing this, and we must release it before
1889  * we actually do the filldir itself, so we use a temp buffer..
1890  */
1891 static int get_tgid_list(int index, unsigned long version, unsigned int *tgids)
1892 {
1893         struct task_struct *p;
1894         int nr_tgids = 0;
1895
1896         index--;
1897         read_lock(&tasklist_lock);
1898         p = NULL;
1899         if (version) {
1900                 p = find_task_by_pid(version);
1901                 if (p && !thread_group_leader(p))
1902                         p = NULL;
1903         }
1904
1905         if (p)
1906                 index = 0;
1907         else
1908                 p = next_task(&init_task);
1909
1910         for ( ; p != &init_task; p = next_task(p)) {
1911                 int tgid = p->pid;
1912                 if (!pid_alive(p))
1913                         continue;
1914                 if (--index >= 0)
1915                         continue;
1916                 tgids[nr_tgids] = tgid;
1917                 nr_tgids++;
1918                 if (nr_tgids >= PROC_MAXPIDS)
1919                         break;
1920         }
1921         read_unlock(&tasklist_lock);
1922         return nr_tgids;
1923 }
1924
1925 /*
1926  * Get a few tid's to return for filldir - we need to hold the
1927  * tasklist lock while doing this, and we must release it before
1928  * we actually do the filldir itself, so we use a temp buffer..
1929  */
1930 static int get_tid_list(int index, unsigned int *tids, struct inode *dir)
1931 {
1932         struct task_struct *leader_task = proc_task(dir);
1933         struct task_struct *task = leader_task;
1934         int nr_tids = 0;
1935
1936         index -= 2;
1937         read_lock(&tasklist_lock);
1938         /*
1939          * The starting point task (leader_task) might be an already
1940          * unlinked task, which cannot be used to access the task-list
1941          * via next_thread().
1942          */
1943         if (pid_alive(task)) do {
1944                 int tid = task->pid;
1945
1946                 if (--index >= 0)
1947                         continue;
1948                 if (tids != NULL)
1949                         tids[nr_tids] = tid;
1950                 nr_tids++;
1951                 if (nr_tids >= PROC_MAXPIDS)
1952                         break;
1953         } while ((task = next_thread(task)) != leader_task);
1954         read_unlock(&tasklist_lock);
1955         return nr_tids;
1956 }
1957
1958 /* for the /proc/ directory itself, after non-process stuff has been done */
1959 int proc_pid_readdir(struct file * filp, void * dirent, filldir_t filldir)
1960 {
1961         unsigned int tgid_array[PROC_MAXPIDS];
1962         char buf[PROC_NUMBUF];
1963         unsigned int nr = filp->f_pos - FIRST_PROCESS_ENTRY;
1964         unsigned int nr_tgids, i;
1965         int next_tgid;
1966
1967         if (!nr) {
1968                 ino_t ino = fake_ino(0,PROC_TGID_INO);
1969                 if (filldir(dirent, "self", 4, filp->f_pos, ino, DT_LNK) < 0)
1970                         return 0;
1971                 filp->f_pos++;
1972                 nr++;
1973         }
1974
1975         /* f_version caches the tgid value that the last readdir call couldn't
1976          * return. lseek aka telldir automagically resets f_version to 0.
1977          */
1978         next_tgid = filp->f_version;
1979         filp->f_version = 0;
1980         for (;;) {
1981                 nr_tgids = get_tgid_list(nr, next_tgid, tgid_array);
1982                 if (!nr_tgids) {
1983                         /* no more entries ! */
1984                         break;
1985                 }
1986                 next_tgid = 0;
1987
1988                 /* do not use the last found pid, reserve it for next_tgid */
1989                 if (nr_tgids == PROC_MAXPIDS) {
1990                         nr_tgids--;
1991                         next_tgid = tgid_array[nr_tgids];
1992                 }
1993
1994                 for (i=0;i<nr_tgids;i++) {
1995                         int tgid = tgid_array[i];
1996                         ino_t ino = fake_ino(tgid,PROC_TGID_INO);
1997                         unsigned long j = PROC_NUMBUF;
1998
1999                         do
2000                                 buf[--j] = '0' + (tgid % 10);
2001                         while ((tgid /= 10) != 0);
2002
2003                         if (filldir(dirent, buf+j, PROC_NUMBUF-j, filp->f_pos, ino, DT_DIR) < 0) {
2004                                 /* returning this tgid failed, save it as the first
2005                                  * pid for the next readir call */
2006                                 filp->f_version = tgid_array[i];
2007                                 goto out;
2008                         }
2009                         filp->f_pos++;
2010                         nr++;
2011                 }
2012         }
2013 out:
2014         return 0;
2015 }
2016
2017 /* for the /proc/TGID/task/ directories */
2018 static int proc_task_readdir(struct file * filp, void * dirent, filldir_t filldir)
2019 {
2020         unsigned int tid_array[PROC_MAXPIDS];
2021         char buf[PROC_NUMBUF];
2022         unsigned int nr_tids, i;
2023         struct dentry *dentry = filp->f_dentry;
2024         struct inode *inode = dentry->d_inode;
2025         int retval = -ENOENT;
2026         ino_t ino;
2027         unsigned long pos = filp->f_pos;  /* avoiding "long long" filp->f_pos */
2028
2029         if (!pid_alive(proc_task(inode)))
2030                 goto out;
2031         retval = 0;
2032
2033         switch (pos) {
2034         case 0:
2035                 ino = inode->i_ino;
2036                 if (filldir(dirent, ".", 1, pos, ino, DT_DIR) < 0)
2037                         goto out;
2038                 pos++;
2039                 /* fall through */
2040         case 1:
2041                 ino = parent_ino(dentry);
2042                 if (filldir(dirent, "..", 2, pos, ino, DT_DIR) < 0)
2043                         goto out;
2044                 pos++;
2045                 /* fall through */
2046         }
2047
2048         nr_tids = get_tid_list(pos, tid_array, inode);
2049         inode->i_nlink = pos + nr_tids;
2050
2051         for (i = 0; i < nr_tids; i++) {
2052                 unsigned long j = PROC_NUMBUF;
2053                 int tid = tid_array[i];
2054
2055                 ino = fake_ino(tid,PROC_TID_INO);
2056
2057                 do
2058                         buf[--j] = '0' + (tid % 10);
2059                 while ((tid /= 10) != 0);
2060
2061                 if (filldir(dirent, buf+j, PROC_NUMBUF-j, pos, ino, DT_DIR) < 0)
2062                         break;
2063                 pos++;
2064         }
2065 out:
2066         filp->f_pos = pos;
2067         return retval;
2068 }