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/errno.h> 53 #include <linux/time.h> 54 #include <linux/proc_fs.h> 55 #include <linux/stat.h> 56 #include <linux/init.h> 57 #include <linux/capability.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/mnt_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 <linux/poll.h> 74 #include <linux/nsproxy.h> 75 #include <linux/oom.h> 76 #include "internal.h" 77 78 /* NOTE: 79 * Implementing inode permission operations in /proc is almost 80 * certainly an error. Permission checks need to happen during 81 * each system call not at open time. The reason is that most of 82 * what we wish to check for permissions in /proc varies at runtime. 83 * 84 * The classic example of a problem is opening file descriptors 85 * in /proc for a task before it execs a suid executable. 86 */ 87 88 89 /* Worst case buffer size needed for holding an integer. */ 90 #define PROC_NUMBUF 13 91 92 struct pid_entry { 93 int len; 94 char *name; 95 mode_t mode; 96 struct inode_operations *iop; 97 struct file_operations *fop; 98 union proc_op op; 99 }; 100 101 #define NOD(NAME, MODE, IOP, FOP, OP) { \ 102 .len = sizeof(NAME) - 1, \ 103 .name = (NAME), \ 104 .mode = MODE, \ 105 .iop = IOP, \ 106 .fop = FOP, \ 107 .op = OP, \ 108 } 109 110 #define DIR(NAME, MODE, OTYPE) \ 111 NOD(NAME, (S_IFDIR|(MODE)), \ 112 &proc_##OTYPE##_inode_operations, &proc_##OTYPE##_operations, \ 113 {} ) 114 #define LNK(NAME, OTYPE) \ 115 NOD(NAME, (S_IFLNK|S_IRWXUGO), \ 116 &proc_pid_link_inode_operations, NULL, \ 117 { .proc_get_link = &proc_##OTYPE##_link } ) 118 #define REG(NAME, MODE, OTYPE) \ 119 NOD(NAME, (S_IFREG|(MODE)), NULL, \ 120 &proc_##OTYPE##_operations, {}) 121 #define INF(NAME, MODE, OTYPE) \ 122 NOD(NAME, (S_IFREG|(MODE)), \ 123 NULL, &proc_info_file_operations, \ 124 { .proc_read = &proc_##OTYPE } ) 125 126 static struct fs_struct *get_fs_struct(struct task_struct *task) 127 { 128 struct fs_struct *fs; 129 task_lock(task); 130 fs = task->fs; 131 if(fs) 132 atomic_inc(&fs->count); 133 task_unlock(task); 134 return fs; 135 } 136 137 static int get_nr_threads(struct task_struct *tsk) 138 { 139 /* Must be called with the rcu_read_lock held */ 140 unsigned long flags; 141 int count = 0; 142 143 if (lock_task_sighand(tsk, &flags)) { 144 count = atomic_read(&tsk->signal->count); 145 unlock_task_sighand(tsk, &flags); 146 } 147 return count; 148 } 149 150 static int proc_cwd_link(struct inode *inode, struct dentry **dentry, struct vfsmount **mnt) 151 { 152 struct task_struct *task = get_proc_task(inode); 153 struct fs_struct *fs = NULL; 154 int result = -ENOENT; 155 156 if (task) { 157 fs = get_fs_struct(task); 158 put_task_struct(task); 159 } 160 if (fs) { 161 read_lock(&fs->lock); 162 *mnt = mntget(fs->pwdmnt); 163 *dentry = dget(fs->pwd); 164 read_unlock(&fs->lock); 165 result = 0; 166 put_fs_struct(fs); 167 } 168 return result; 169 } 170 171 static int proc_root_link(struct inode *inode, struct dentry **dentry, struct vfsmount **mnt) 172 { 173 struct task_struct *task = get_proc_task(inode); 174 struct fs_struct *fs = NULL; 175 int result = -ENOENT; 176 177 if (task) { 178 fs = get_fs_struct(task); 179 put_task_struct(task); 180 } 181 if (fs) { 182 read_lock(&fs->lock); 183 *mnt = mntget(fs->rootmnt); 184 *dentry = dget(fs->root); 185 read_unlock(&fs->lock); 186 result = 0; 187 put_fs_struct(fs); 188 } 189 return result; 190 } 191 192 #define MAY_PTRACE(task) \ 193 (task == current || \ 194 (task->parent == current && \ 195 (task->ptrace & PT_PTRACED) && \ 196 (task->state == TASK_STOPPED || task->state == TASK_TRACED) && \ 197 security_ptrace(current,task) == 0)) 198 199 static int proc_pid_environ(struct task_struct *task, char * buffer) 200 { 201 int res = 0; 202 struct mm_struct *mm = get_task_mm(task); 203 if (mm) { 204 unsigned int len = mm->env_end - mm->env_start; 205 if (len > PAGE_SIZE) 206 len = PAGE_SIZE; 207 res = access_process_vm(task, mm->env_start, buffer, len, 0); 208 if (!ptrace_may_attach(task)) 209 res = -ESRCH; 210 mmput(mm); 211 } 212 return res; 213 } 214 215 static int proc_pid_cmdline(struct task_struct *task, char * buffer) 216 { 217 int res = 0; 218 unsigned int len; 219 struct mm_struct *mm = get_task_mm(task); 220 if (!mm) 221 goto out; 222 if (!mm->arg_end) 223 goto out_mm; /* Shh! No looking before we're done */ 224 225 len = mm->arg_end - mm->arg_start; 226 227 if (len > PAGE_SIZE) 228 len = PAGE_SIZE; 229 230 res = access_process_vm(task, mm->arg_start, buffer, len, 0); 231 232 // If the nul at the end of args has been overwritten, then 233 // assume application is using setproctitle(3). 234 if (res > 0 && buffer[res-1] != '\0' && len < PAGE_SIZE) { 235 len = strnlen(buffer, res); 236 if (len < res) { 237 res = len; 238 } else { 239 len = mm->env_end - mm->env_start; 240 if (len > PAGE_SIZE - res) 241 len = PAGE_SIZE - res; 242 res += access_process_vm(task, mm->env_start, buffer+res, len, 0); 243 res = strnlen(buffer, res); 244 } 245 } 246 out_mm: 247 mmput(mm); 248 out: 249 return res; 250 } 251 252 static int proc_pid_auxv(struct task_struct *task, char *buffer) 253 { 254 int res = 0; 255 struct mm_struct *mm = get_task_mm(task); 256 if (mm) { 257 unsigned int nwords = 0; 258 do 259 nwords += 2; 260 while (mm->saved_auxv[nwords - 2] != 0); /* AT_NULL */ 261 res = nwords * sizeof(mm->saved_auxv[0]); 262 if (res > PAGE_SIZE) 263 res = PAGE_SIZE; 264 memcpy(buffer, mm->saved_auxv, res); 265 mmput(mm); 266 } 267 return res; 268 } 269 270 271 #ifdef CONFIG_KALLSYMS 272 /* 273 * Provides a wchan file via kallsyms in a proper one-value-per-file format. 274 * Returns the resolved symbol. If that fails, simply return the address. 275 */ 276 static int proc_pid_wchan(struct task_struct *task, char *buffer) 277 { 278 char *modname; 279 const char *sym_name; 280 unsigned long wchan, size, offset; 281 char namebuf[KSYM_NAME_LEN+1]; 282 283 wchan = get_wchan(task); 284 285 sym_name = kallsyms_lookup(wchan, &size, &offset, &modname, namebuf); 286 if (sym_name) 287 return sprintf(buffer, "%s", sym_name); 288 return sprintf(buffer, "%lu", wchan); 289 } 290 #endif /* CONFIG_KALLSYMS */ 291 292 #ifdef CONFIG_SCHEDSTATS 293 /* 294 * Provides /proc/PID/schedstat 295 */ 296 static int proc_pid_schedstat(struct task_struct *task, char *buffer) 297 { 298 return sprintf(buffer, "%lu %lu %lu\n", 299 task->sched_info.cpu_time, 300 task->sched_info.run_delay, 301 task->sched_info.pcnt); 302 } 303 #endif 304 305 /* The badness from the OOM killer */ 306 unsigned long badness(struct task_struct *p, unsigned long uptime); 307 static int proc_oom_score(struct task_struct *task, char *buffer) 308 { 309 unsigned long points; 310 struct timespec uptime; 311 312 do_posix_clock_monotonic_gettime(&uptime); 313 points = badness(task, uptime.tv_sec); 314 return sprintf(buffer, "%lu\n", points); 315 } 316 317 /************************************************************************/ 318 /* Here the fs part begins */ 319 /************************************************************************/ 320 321 /* permission checks */ 322 static int proc_fd_access_allowed(struct inode *inode) 323 { 324 struct task_struct *task; 325 int allowed = 0; 326 /* Allow access to a task's file descriptors if it is us or we 327 * may use ptrace attach to the process and find out that 328 * information. 329 */ 330 task = get_proc_task(inode); 331 if (task) { 332 allowed = ptrace_may_attach(task); 333 put_task_struct(task); 334 } 335 return allowed; 336 } 337 338 static int proc_setattr(struct dentry *dentry, struct iattr *attr) 339 { 340 int error; 341 struct inode *inode = dentry->d_inode; 342 343 if (attr->ia_valid & ATTR_MODE) 344 return -EPERM; 345 346 error = inode_change_ok(inode, attr); 347 if (!error) { 348 error = security_inode_setattr(dentry, attr); 349 if (!error) 350 error = inode_setattr(inode, attr); 351 } 352 return error; 353 } 354 355 static struct inode_operations proc_def_inode_operations = { 356 .setattr = proc_setattr, 357 }; 358 359 extern struct seq_operations mounts_op; 360 struct proc_mounts { 361 struct seq_file m; 362 int event; 363 }; 364 365 static int mounts_open(struct inode *inode, struct file *file) 366 { 367 struct task_struct *task = get_proc_task(inode); 368 struct mnt_namespace *ns = NULL; 369 struct proc_mounts *p; 370 int ret = -EINVAL; 371 372 if (task) { 373 task_lock(task); 374 if (task->nsproxy) { 375 ns = task->nsproxy->mnt_ns; 376 if (ns) 377 get_mnt_ns(ns); 378 } 379 task_unlock(task); 380 put_task_struct(task); 381 } 382 383 if (ns) { 384 ret = -ENOMEM; 385 p = kmalloc(sizeof(struct proc_mounts), GFP_KERNEL); 386 if (p) { 387 file->private_data = &p->m; 388 ret = seq_open(file, &mounts_op); 389 if (!ret) { 390 p->m.private = ns; 391 p->event = ns->event; 392 return 0; 393 } 394 kfree(p); 395 } 396 put_mnt_ns(ns); 397 } 398 return ret; 399 } 400 401 static int mounts_release(struct inode *inode, struct file *file) 402 { 403 struct seq_file *m = file->private_data; 404 struct mnt_namespace *ns = m->private; 405 put_mnt_ns(ns); 406 return seq_release(inode, file); 407 } 408 409 static unsigned mounts_poll(struct file *file, poll_table *wait) 410 { 411 struct proc_mounts *p = file->private_data; 412 struct mnt_namespace *ns = p->m.private; 413 unsigned res = 0; 414 415 poll_wait(file, &ns->poll, wait); 416 417 spin_lock(&vfsmount_lock); 418 if (p->event != ns->event) { 419 p->event = ns->event; 420 res = POLLERR; 421 } 422 spin_unlock(&vfsmount_lock); 423 424 return res; 425 } 426 427 static struct file_operations proc_mounts_operations = { 428 .open = mounts_open, 429 .read = seq_read, 430 .llseek = seq_lseek, 431 .release = mounts_release, 432 .poll = mounts_poll, 433 }; 434 435 extern struct seq_operations mountstats_op; 436 static int mountstats_open(struct inode *inode, struct file *file) 437 { 438 int ret = seq_open(file, &mountstats_op); 439 440 if (!ret) { 441 struct seq_file *m = file->private_data; 442 struct mnt_namespace *mnt_ns = NULL; 443 struct task_struct *task = get_proc_task(inode); 444 445 if (task) { 446 task_lock(task); 447 if (task->nsproxy) 448 mnt_ns = task->nsproxy->mnt_ns; 449 if (mnt_ns) 450 get_mnt_ns(mnt_ns); 451 task_unlock(task); 452 put_task_struct(task); 453 } 454 455 if (mnt_ns) 456 m->private = mnt_ns; 457 else { 458 seq_release(inode, file); 459 ret = -EINVAL; 460 } 461 } 462 return ret; 463 } 464 465 static struct file_operations proc_mountstats_operations = { 466 .open = mountstats_open, 467 .read = seq_read, 468 .llseek = seq_lseek, 469 .release = mounts_release, 470 }; 471 472 #define PROC_BLOCK_SIZE (3*1024) /* 4K page size but our output routines use some slack for overruns */ 473 474 static ssize_t proc_info_read(struct file * file, char __user * buf, 475 size_t count, loff_t *ppos) 476 { 477 struct inode * inode = file->f_path.dentry->d_inode; 478 unsigned long page; 479 ssize_t length; 480 struct task_struct *task = get_proc_task(inode); 481 482 length = -ESRCH; 483 if (!task) 484 goto out_no_task; 485 486 if (count > PROC_BLOCK_SIZE) 487 count = PROC_BLOCK_SIZE; 488 489 length = -ENOMEM; 490 if (!(page = __get_free_page(GFP_KERNEL))) 491 goto out; 492 493 length = PROC_I(inode)->op.proc_read(task, (char*)page); 494 495 if (length >= 0) 496 length = simple_read_from_buffer(buf, count, ppos, (char *)page, length); 497 free_page(page); 498 out: 499 put_task_struct(task); 500 out_no_task: 501 return length; 502 } 503 504 static struct file_operations proc_info_file_operations = { 505 .read = proc_info_read, 506 }; 507 508 static int mem_open(struct inode* inode, struct file* file) 509 { 510 file->private_data = (void*)((long)current->self_exec_id); 511 return 0; 512 } 513 514 static ssize_t mem_read(struct file * file, char __user * buf, 515 size_t count, loff_t *ppos) 516 { 517 struct task_struct *task = get_proc_task(file->f_path.dentry->d_inode); 518 char *page; 519 unsigned long src = *ppos; 520 int ret = -ESRCH; 521 struct mm_struct *mm; 522 523 if (!task) 524 goto out_no_task; 525 526 if (!MAY_PTRACE(task) || !ptrace_may_attach(task)) 527 goto out; 528 529 ret = -ENOMEM; 530 page = (char *)__get_free_page(GFP_USER); 531 if (!page) 532 goto out; 533 534 ret = 0; 535 536 mm = get_task_mm(task); 537 if (!mm) 538 goto out_free; 539 540 ret = -EIO; 541 542 if (file->private_data != (void*)((long)current->self_exec_id)) 543 goto out_put; 544 545 ret = 0; 546 547 while (count > 0) { 548 int this_len, retval; 549 550 this_len = (count > PAGE_SIZE) ? PAGE_SIZE : count; 551 retval = access_process_vm(task, src, page, this_len, 0); 552 if (!retval || !MAY_PTRACE(task) || !ptrace_may_attach(task)) { 553 if (!ret) 554 ret = -EIO; 555 break; 556 } 557 558 if (copy_to_user(buf, page, retval)) { 559 ret = -EFAULT; 560 break; 561 } 562 563 ret += retval; 564 src += retval; 565 buf += retval; 566 count -= retval; 567 } 568 *ppos = src; 569 570 out_put: 571 mmput(mm); 572 out_free: 573 free_page((unsigned long) page); 574 out: 575 put_task_struct(task); 576 out_no_task: 577 return ret; 578 } 579 580 #define mem_write NULL 581 582 #ifndef mem_write 583 /* This is a security hazard */ 584 static ssize_t mem_write(struct file * file, const char * buf, 585 size_t count, loff_t *ppos) 586 { 587 int copied; 588 char *page; 589 struct task_struct *task = get_proc_task(file->f_path.dentry->d_inode); 590 unsigned long dst = *ppos; 591 592 copied = -ESRCH; 593 if (!task) 594 goto out_no_task; 595 596 if (!MAY_PTRACE(task) || !ptrace_may_attach(task)) 597 goto out; 598 599 copied = -ENOMEM; 600 page = (char *)__get_free_page(GFP_USER); 601 if (!page) 602 goto out; 603 604 copied = 0; 605 while (count > 0) { 606 int this_len, retval; 607 608 this_len = (count > PAGE_SIZE) ? PAGE_SIZE : count; 609 if (copy_from_user(page, buf, this_len)) { 610 copied = -EFAULT; 611 break; 612 } 613 retval = access_process_vm(task, dst, page, this_len, 1); 614 if (!retval) { 615 if (!copied) 616 copied = -EIO; 617 break; 618 } 619 copied += retval; 620 buf += retval; 621 dst += retval; 622 count -= retval; 623 } 624 *ppos = dst; 625 free_page((unsigned long) page); 626 out: 627 put_task_struct(task); 628 out_no_task: 629 return copied; 630 } 631 #endif 632 633 static loff_t mem_lseek(struct file * file, loff_t offset, int orig) 634 { 635 switch (orig) { 636 case 0: 637 file->f_pos = offset; 638 break; 639 case 1: 640 file->f_pos += offset; 641 break; 642 default: 643 return -EINVAL; 644 } 645 force_successful_syscall_return(); 646 return file->f_pos; 647 } 648 649 static struct file_operations proc_mem_operations = { 650 .llseek = mem_lseek, 651 .read = mem_read, 652 .write = mem_write, 653 .open = mem_open, 654 }; 655 656 static ssize_t oom_adjust_read(struct file *file, char __user *buf, 657 size_t count, loff_t *ppos) 658 { 659 struct task_struct *task = get_proc_task(file->f_path.dentry->d_inode); 660 char buffer[PROC_NUMBUF]; 661 size_t len; 662 int oom_adjust; 663 loff_t __ppos = *ppos; 664 665 if (!task) 666 return -ESRCH; 667 oom_adjust = task->oomkilladj; 668 put_task_struct(task); 669 670 len = snprintf(buffer, sizeof(buffer), "%i\n", oom_adjust); 671 if (__ppos >= len) 672 return 0; 673 if (count > len-__ppos) 674 count = len-__ppos; 675 if (copy_to_user(buf, buffer + __ppos, count)) 676 return -EFAULT; 677 *ppos = __ppos + count; 678 return count; 679 } 680 681 static ssize_t oom_adjust_write(struct file *file, const char __user *buf, 682 size_t count, loff_t *ppos) 683 { 684 struct task_struct *task; 685 char buffer[PROC_NUMBUF], *end; 686 int oom_adjust; 687 688 memset(buffer, 0, sizeof(buffer)); 689 if (count > sizeof(buffer) - 1) 690 count = sizeof(buffer) - 1; 691 if (copy_from_user(buffer, buf, count)) 692 return -EFAULT; 693 oom_adjust = simple_strtol(buffer, &end, 0); 694 if ((oom_adjust < OOM_ADJUST_MIN || oom_adjust > OOM_ADJUST_MAX) && 695 oom_adjust != OOM_DISABLE) 696 return -EINVAL; 697 if (*end == '\n') 698 end++; 699 task = get_proc_task(file->f_path.dentry->d_inode); 700 if (!task) 701 return -ESRCH; 702 if (oom_adjust < task->oomkilladj && !capable(CAP_SYS_RESOURCE)) { 703 put_task_struct(task); 704 return -EACCES; 705 } 706 task->oomkilladj = oom_adjust; 707 put_task_struct(task); 708 if (end - buffer == 0) 709 return -EIO; 710 return end - buffer; 711 } 712 713 static struct file_operations proc_oom_adjust_operations = { 714 .read = oom_adjust_read, 715 .write = oom_adjust_write, 716 }; 717 718 #ifdef CONFIG_AUDITSYSCALL 719 #define TMPBUFLEN 21 720 static ssize_t proc_loginuid_read(struct file * file, char __user * buf, 721 size_t count, loff_t *ppos) 722 { 723 struct inode * inode = file->f_path.dentry->d_inode; 724 struct task_struct *task = get_proc_task(inode); 725 ssize_t length; 726 char tmpbuf[TMPBUFLEN]; 727 728 if (!task) 729 return -ESRCH; 730 length = scnprintf(tmpbuf, TMPBUFLEN, "%u", 731 audit_get_loginuid(task->audit_context)); 732 put_task_struct(task); 733 return simple_read_from_buffer(buf, count, ppos, tmpbuf, length); 734 } 735 736 static ssize_t proc_loginuid_write(struct file * file, const char __user * buf, 737 size_t count, loff_t *ppos) 738 { 739 struct inode * inode = file->f_path.dentry->d_inode; 740 char *page, *tmp; 741 ssize_t length; 742 uid_t loginuid; 743 744 if (!capable(CAP_AUDIT_CONTROL)) 745 return -EPERM; 746 747 if (current != pid_task(proc_pid(inode), PIDTYPE_PID)) 748 return -EPERM; 749 750 if (count >= PAGE_SIZE) 751 count = PAGE_SIZE - 1; 752 753 if (*ppos != 0) { 754 /* No partial writes. */ 755 return -EINVAL; 756 } 757 page = (char*)__get_free_page(GFP_USER); 758 if (!page) 759 return -ENOMEM; 760 length = -EFAULT; 761 if (copy_from_user(page, buf, count)) 762 goto out_free_page; 763 764 page[count] = '\0'; 765 loginuid = simple_strtoul(page, &tmp, 10); 766 if (tmp == page) { 767 length = -EINVAL; 768 goto out_free_page; 769 770 } 771 length = audit_set_loginuid(current, loginuid); 772 if (likely(length == 0)) 773 length = count; 774 775 out_free_page: 776 free_page((unsigned long) page); 777 return length; 778 } 779 780 static struct file_operations proc_loginuid_operations = { 781 .read = proc_loginuid_read, 782 .write = proc_loginuid_write, 783 }; 784 #endif 785 786 #ifdef CONFIG_SECCOMP 787 static ssize_t seccomp_read(struct file *file, char __user *buf, 788 size_t count, loff_t *ppos) 789 { 790 struct task_struct *tsk = get_proc_task(file->f_dentry->d_inode); 791 char __buf[20]; 792 loff_t __ppos = *ppos; 793 size_t len; 794 795 if (!tsk) 796 return -ESRCH; 797 /* no need to print the trailing zero, so use only len */ 798 len = sprintf(__buf, "%u\n", tsk->seccomp.mode); 799 put_task_struct(tsk); 800 if (__ppos >= len) 801 return 0; 802 if (count > len - __ppos) 803 count = len - __ppos; 804 if (copy_to_user(buf, __buf + __ppos, count)) 805 return -EFAULT; 806 *ppos = __ppos + count; 807 return count; 808 } 809 810 static ssize_t seccomp_write(struct file *file, const char __user *buf, 811 size_t count, loff_t *ppos) 812 { 813 struct task_struct *tsk = get_proc_task(file->f_dentry->d_inode); 814 char __buf[20], *end; 815 unsigned int seccomp_mode; 816 ssize_t result; 817 818 result = -ESRCH; 819 if (!tsk) 820 goto out_no_task; 821 822 /* can set it only once to be even more secure */ 823 result = -EPERM; 824 if (unlikely(tsk->seccomp.mode)) 825 goto out; 826 827 result = -EFAULT; 828 memset(__buf, 0, sizeof(__buf)); 829 count = min(count, sizeof(__buf) - 1); 830 if (copy_from_user(__buf, buf, count)) 831 goto out; 832 833 seccomp_mode = simple_strtoul(__buf, &end, 0); 834 if (*end == '\n') 835 end++; 836 result = -EINVAL; 837 if (seccomp_mode && seccomp_mode <= NR_SECCOMP_MODES) { 838 tsk->seccomp.mode = seccomp_mode; 839 set_tsk_thread_flag(tsk, TIF_SECCOMP); 840 } else 841 goto out; 842 result = -EIO; 843 if (unlikely(!(end - __buf))) 844 goto out; 845 result = end - __buf; 846 out: 847 put_task_struct(tsk); 848 out_no_task: 849 return result; 850 } 851 852 static struct file_operations proc_seccomp_operations = { 853 .read = seccomp_read, 854 .write = seccomp_write, 855 }; 856 #endif /* CONFIG_SECCOMP */ 857 858 #ifdef CONFIG_FAULT_INJECTION 859 static ssize_t proc_fault_inject_read(struct file * file, char __user * buf, 860 size_t count, loff_t *ppos) 861 { 862 struct task_struct *task = get_proc_task(file->f_dentry->d_inode); 863 char buffer[PROC_NUMBUF]; 864 size_t len; 865 int make_it_fail; 866 loff_t __ppos = *ppos; 867 868 if (!task) 869 return -ESRCH; 870 make_it_fail = task->make_it_fail; 871 put_task_struct(task); 872 873 len = snprintf(buffer, sizeof(buffer), "%i\n", make_it_fail); 874 if (__ppos >= len) 875 return 0; 876 if (count > len-__ppos) 877 count = len-__ppos; 878 if (copy_to_user(buf, buffer + __ppos, count)) 879 return -EFAULT; 880 *ppos = __ppos + count; 881 return count; 882 } 883 884 static ssize_t proc_fault_inject_write(struct file * file, 885 const char __user * buf, size_t count, loff_t *ppos) 886 { 887 struct task_struct *task; 888 char buffer[PROC_NUMBUF], *end; 889 int make_it_fail; 890 891 if (!capable(CAP_SYS_RESOURCE)) 892 return -EPERM; 893 memset(buffer, 0, sizeof(buffer)); 894 if (count > sizeof(buffer) - 1) 895 count = sizeof(buffer) - 1; 896 if (copy_from_user(buffer, buf, count)) 897 return -EFAULT; 898 make_it_fail = simple_strtol(buffer, &end, 0); 899 if (*end == '\n') 900 end++; 901 task = get_proc_task(file->f_dentry->d_inode); 902 if (!task) 903 return -ESRCH; 904 task->make_it_fail = make_it_fail; 905 put_task_struct(task); 906 if (end - buffer == 0) 907 return -EIO; 908 return end - buffer; 909 } 910 911 static struct file_operations proc_fault_inject_operations = { 912 .read = proc_fault_inject_read, 913 .write = proc_fault_inject_write, 914 }; 915 #endif 916 917 static void *proc_pid_follow_link(struct dentry *dentry, struct nameidata *nd) 918 { 919 struct inode *inode = dentry->d_inode; 920 int error = -EACCES; 921 922 /* We don't need a base pointer in the /proc filesystem */ 923 path_release(nd); 924 925 /* Are we allowed to snoop on the tasks file descriptors? */ 926 if (!proc_fd_access_allowed(inode)) 927 goto out; 928 929 error = PROC_I(inode)->op.proc_get_link(inode, &nd->dentry, &nd->mnt); 930 nd->last_type = LAST_BIND; 931 out: 932 return ERR_PTR(error); 933 } 934 935 static int do_proc_readlink(struct dentry *dentry, struct vfsmount *mnt, 936 char __user *buffer, int buflen) 937 { 938 struct inode * inode; 939 char *tmp = (char*)__get_free_page(GFP_KERNEL), *path; 940 int len; 941 942 if (!tmp) 943 return -ENOMEM; 944 945 inode = dentry->d_inode; 946 path = d_path(dentry, mnt, tmp, PAGE_SIZE); 947 len = PTR_ERR(path); 948 if (IS_ERR(path)) 949 goto out; 950 len = tmp + PAGE_SIZE - 1 - path; 951 952 if (len > buflen) 953 len = buflen; 954 if (copy_to_user(buffer, path, len)) 955 len = -EFAULT; 956 out: 957 free_page((unsigned long)tmp); 958 return len; 959 } 960 961 static int proc_pid_readlink(struct dentry * dentry, char __user * buffer, int buflen) 962 { 963 int error = -EACCES; 964 struct inode *inode = dentry->d_inode; 965 struct dentry *de; 966 struct vfsmount *mnt = NULL; 967 968 /* Are we allowed to snoop on the tasks file descriptors? */ 969 if (!proc_fd_access_allowed(inode)) 970 goto out; 971 972 error = PROC_I(inode)->op.proc_get_link(inode, &de, &mnt); 973 if (error) 974 goto out; 975 976 error = do_proc_readlink(de, mnt, buffer, buflen); 977 dput(de); 978 mntput(mnt); 979 out: 980 return error; 981 } 982 983 static struct inode_operations proc_pid_link_inode_operations = { 984 .readlink = proc_pid_readlink, 985 .follow_link = proc_pid_follow_link, 986 .setattr = proc_setattr, 987 }; 988 989 990 /* building an inode */ 991 992 static int task_dumpable(struct task_struct *task) 993 { 994 int dumpable = 0; 995 struct mm_struct *mm; 996 997 task_lock(task); 998 mm = task->mm; 999 if (mm) 1000 dumpable = mm->dumpable; 1001 task_unlock(task); 1002 if(dumpable == 1) 1003 return 1; 1004 return 0; 1005 } 1006 1007 1008 static struct inode *proc_pid_make_inode(struct super_block * sb, struct task_struct *task) 1009 { 1010 struct inode * inode; 1011 struct proc_inode *ei; 1012 1013 /* We need a new inode */ 1014 1015 inode = new_inode(sb); 1016 if (!inode) 1017 goto out; 1018 1019 /* Common stuff */ 1020 ei = PROC_I(inode); 1021 inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME; 1022 inode->i_op = &proc_def_inode_operations; 1023 1024 /* 1025 * grab the reference to task. 1026 */ 1027 ei->pid = get_task_pid(task, PIDTYPE_PID); 1028 if (!ei->pid) 1029 goto out_unlock; 1030 1031 inode->i_uid = 0; 1032 inode->i_gid = 0; 1033 if (task_dumpable(task)) { 1034 inode->i_uid = task->euid; 1035 inode->i_gid = task->egid; 1036 } 1037 security_task_to_inode(task, inode); 1038 1039 out: 1040 return inode; 1041 1042 out_unlock: 1043 iput(inode); 1044 return NULL; 1045 } 1046 1047 static int pid_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat) 1048 { 1049 struct inode *inode = dentry->d_inode; 1050 struct task_struct *task; 1051 generic_fillattr(inode, stat); 1052 1053 rcu_read_lock(); 1054 stat->uid = 0; 1055 stat->gid = 0; 1056 task = pid_task(proc_pid(inode), PIDTYPE_PID); 1057 if (task) { 1058 if ((inode->i_mode == (S_IFDIR|S_IRUGO|S_IXUGO)) || 1059 task_dumpable(task)) { 1060 stat->uid = task->euid; 1061 stat->gid = task->egid; 1062 } 1063 } 1064 rcu_read_unlock(); 1065 return 0; 1066 } 1067 1068 /* dentry stuff */ 1069 1070 /* 1071 * Exceptional case: normally we are not allowed to unhash a busy 1072 * directory. In this case, however, we can do it - no aliasing problems 1073 * due to the way we treat inodes. 1074 * 1075 * Rewrite the inode's ownerships here because the owning task may have 1076 * performed a setuid(), etc. 1077 * 1078 * Before the /proc/pid/status file was created the only way to read 1079 * the effective uid of a /process was to stat /proc/pid. Reading 1080 * /proc/pid/status is slow enough that procps and other packages 1081 * kept stating /proc/pid. To keep the rules in /proc simple I have 1082 * made this apply to all per process world readable and executable 1083 * directories. 1084 */ 1085 static int pid_revalidate(struct dentry *dentry, struct nameidata *nd) 1086 { 1087 struct inode *inode = dentry->d_inode; 1088 struct task_struct *task = get_proc_task(inode); 1089 if (task) { 1090 if ((inode->i_mode == (S_IFDIR|S_IRUGO|S_IXUGO)) || 1091 task_dumpable(task)) { 1092 inode->i_uid = task->euid; 1093 inode->i_gid = task->egid; 1094 } else { 1095 inode->i_uid = 0; 1096 inode->i_gid = 0; 1097 } 1098 inode->i_mode &= ~(S_ISUID | S_ISGID); 1099 security_task_to_inode(task, inode); 1100 put_task_struct(task); 1101 return 1; 1102 } 1103 d_drop(dentry); 1104 return 0; 1105 } 1106 1107 static int pid_delete_dentry(struct dentry * dentry) 1108 { 1109 /* Is the task we represent dead? 1110 * If so, then don't put the dentry on the lru list, 1111 * kill it immediately. 1112 */ 1113 return !proc_pid(dentry->d_inode)->tasks[PIDTYPE_PID].first; 1114 } 1115 1116 static struct dentry_operations pid_dentry_operations = 1117 { 1118 .d_revalidate = pid_revalidate, 1119 .d_delete = pid_delete_dentry, 1120 }; 1121 1122 /* Lookups */ 1123 1124 typedef struct dentry *instantiate_t(struct inode *, struct dentry *, struct task_struct *, void *); 1125 1126 /* 1127 * Fill a directory entry. 1128 * 1129 * If possible create the dcache entry and derive our inode number and 1130 * file type from dcache entry. 1131 * 1132 * Since all of the proc inode numbers are dynamically generated, the inode 1133 * numbers do not exist until the inode is cache. This means creating the 1134 * the dcache entry in readdir is necessary to keep the inode numbers 1135 * reported by readdir in sync with the inode numbers reported 1136 * by stat. 1137 */ 1138 static int proc_fill_cache(struct file *filp, void *dirent, filldir_t filldir, 1139 char *name, int len, 1140 instantiate_t instantiate, struct task_struct *task, void *ptr) 1141 { 1142 struct dentry *child, *dir = filp->f_path.dentry; 1143 struct inode *inode; 1144 struct qstr qname; 1145 ino_t ino = 0; 1146 unsigned type = DT_UNKNOWN; 1147 1148 qname.name = name; 1149 qname.len = len; 1150 qname.hash = full_name_hash(name, len); 1151 1152 child = d_lookup(dir, &qname); 1153 if (!child) { 1154 struct dentry *new; 1155 new = d_alloc(dir, &qname); 1156 if (new) { 1157 child = instantiate(dir->d_inode, new, task, ptr); 1158 if (child) 1159 dput(new); 1160 else 1161 child = new; 1162 } 1163 } 1164 if (!child || IS_ERR(child) || !child->d_inode) 1165 goto end_instantiate; 1166 inode = child->d_inode; 1167 if (inode) { 1168 ino = inode->i_ino; 1169 type = inode->i_mode >> 12; 1170 } 1171 dput(child); 1172 end_instantiate: 1173 if (!ino) 1174 ino = find_inode_number(dir, &qname); 1175 if (!ino) 1176 ino = 1; 1177 return filldir(dirent, name, len, filp->f_pos, ino, type); 1178 } 1179 1180 static unsigned name_to_int(struct dentry *dentry) 1181 { 1182 const char *name = dentry->d_name.name; 1183 int len = dentry->d_name.len; 1184 unsigned n = 0; 1185 1186 if (len > 1 && *name == '0') 1187 goto out; 1188 while (len-- > 0) { 1189 unsigned c = *name++ - '0'; 1190 if (c > 9) 1191 goto out; 1192 if (n >= (~0U-9)/10) 1193 goto out; 1194 n *= 10; 1195 n += c; 1196 } 1197 return n; 1198 out: 1199 return ~0U; 1200 } 1201 1202 static int proc_fd_link(struct inode *inode, struct dentry **dentry, struct vfsmount **mnt) 1203 { 1204 struct task_struct *task = get_proc_task(inode); 1205 struct files_struct *files = NULL; 1206 struct file *file; 1207 int fd = proc_fd(inode); 1208 1209 if (task) { 1210 files = get_files_struct(task); 1211 put_task_struct(task); 1212 } 1213 if (files) { 1214 /* 1215 * We are not taking a ref to the file structure, so we must 1216 * hold ->file_lock. 1217 */ 1218 spin_lock(&files->file_lock); 1219 file = fcheck_files(files, fd); 1220 if (file) { 1221 *mnt = mntget(file->f_path.mnt); 1222 *dentry = dget(file->f_path.dentry); 1223 spin_unlock(&files->file_lock); 1224 put_files_struct(files); 1225 return 0; 1226 } 1227 spin_unlock(&files->file_lock); 1228 put_files_struct(files); 1229 } 1230 return -ENOENT; 1231 } 1232 1233 static int tid_fd_revalidate(struct dentry *dentry, struct nameidata *nd) 1234 { 1235 struct inode *inode = dentry->d_inode; 1236 struct task_struct *task = get_proc_task(inode); 1237 int fd = proc_fd(inode); 1238 struct files_struct *files; 1239 1240 if (task) { 1241 files = get_files_struct(task); 1242 if (files) { 1243 rcu_read_lock(); 1244 if (fcheck_files(files, fd)) { 1245 rcu_read_unlock(); 1246 put_files_struct(files); 1247 if (task_dumpable(task)) { 1248 inode->i_uid = task->euid; 1249 inode->i_gid = task->egid; 1250 } else { 1251 inode->i_uid = 0; 1252 inode->i_gid = 0; 1253 } 1254 inode->i_mode &= ~(S_ISUID | S_ISGID); 1255 security_task_to_inode(task, inode); 1256 put_task_struct(task); 1257 return 1; 1258 } 1259 rcu_read_unlock(); 1260 put_files_struct(files); 1261 } 1262 put_task_struct(task); 1263 } 1264 d_drop(dentry); 1265 return 0; 1266 } 1267 1268 static struct dentry_operations tid_fd_dentry_operations = 1269 { 1270 .d_revalidate = tid_fd_revalidate, 1271 .d_delete = pid_delete_dentry, 1272 }; 1273 1274 static struct dentry *proc_fd_instantiate(struct inode *dir, 1275 struct dentry *dentry, struct task_struct *task, void *ptr) 1276 { 1277 unsigned fd = *(unsigned *)ptr; 1278 struct file *file; 1279 struct files_struct *files; 1280 struct inode *inode; 1281 struct proc_inode *ei; 1282 struct dentry *error = ERR_PTR(-ENOENT); 1283 1284 inode = proc_pid_make_inode(dir->i_sb, task); 1285 if (!inode) 1286 goto out; 1287 ei = PROC_I(inode); 1288 ei->fd = fd; 1289 files = get_files_struct(task); 1290 if (!files) 1291 goto out_iput; 1292 inode->i_mode = S_IFLNK; 1293 1294 /* 1295 * We are not taking a ref to the file structure, so we must 1296 * hold ->file_lock. 1297 */ 1298 spin_lock(&files->file_lock); 1299 file = fcheck_files(files, fd); 1300 if (!file) 1301 goto out_unlock; 1302 if (file->f_mode & 1) 1303 inode->i_mode |= S_IRUSR | S_IXUSR; 1304 if (file->f_mode & 2) 1305 inode->i_mode |= S_IWUSR | S_IXUSR; 1306 spin_unlock(&files->file_lock); 1307 put_files_struct(files); 1308 1309 inode->i_op = &proc_pid_link_inode_operations; 1310 inode->i_size = 64; 1311 ei->op.proc_get_link = proc_fd_link; 1312 dentry->d_op = &tid_fd_dentry_operations; 1313 d_add(dentry, inode); 1314 /* Close the race of the process dying before we return the dentry */ 1315 if (tid_fd_revalidate(dentry, NULL)) 1316 error = NULL; 1317 1318 out: 1319 return error; 1320 out_unlock: 1321 spin_unlock(&files->file_lock); 1322 put_files_struct(files); 1323 out_iput: 1324 iput(inode); 1325 goto out; 1326 } 1327 1328 static struct dentry *proc_lookupfd(struct inode * dir, struct dentry * dentry, struct nameidata *nd) 1329 { 1330 struct task_struct *task = get_proc_task(dir); 1331 unsigned fd = name_to_int(dentry); 1332 struct dentry *result = ERR_PTR(-ENOENT); 1333 1334 if (!task) 1335 goto out_no_task; 1336 if (fd == ~0U) 1337 goto out; 1338 1339 result = proc_fd_instantiate(dir, dentry, task, &fd); 1340 out: 1341 put_task_struct(task); 1342 out_no_task: 1343 return result; 1344 } 1345 1346 static int proc_fd_fill_cache(struct file *filp, void *dirent, filldir_t filldir, 1347 struct task_struct *task, int fd) 1348 { 1349 char name[PROC_NUMBUF]; 1350 int len = snprintf(name, sizeof(name), "%d", fd); 1351 return proc_fill_cache(filp, dirent, filldir, name, len, 1352 proc_fd_instantiate, task, &fd); 1353 } 1354 1355 static int proc_readfd(struct file * filp, void * dirent, filldir_t filldir) 1356 { 1357 struct dentry *dentry = filp->f_path.dentry; 1358 struct inode *inode = dentry->d_inode; 1359 struct task_struct *p = get_proc_task(inode); 1360 unsigned int fd, tid, ino; 1361 int retval; 1362 struct files_struct * files; 1363 struct fdtable *fdt; 1364 1365 retval = -ENOENT; 1366 if (!p) 1367 goto out_no_task; 1368 retval = 0; 1369 tid = p->pid; 1370 1371 fd = filp->f_pos; 1372 switch (fd) { 1373 case 0: 1374 if (filldir(dirent, ".", 1, 0, inode->i_ino, DT_DIR) < 0) 1375 goto out; 1376 filp->f_pos++; 1377 case 1: 1378 ino = parent_ino(dentry); 1379 if (filldir(dirent, "..", 2, 1, ino, DT_DIR) < 0) 1380 goto out; 1381 filp->f_pos++; 1382 default: 1383 files = get_files_struct(p); 1384 if (!files) 1385 goto out; 1386 rcu_read_lock(); 1387 fdt = files_fdtable(files); 1388 for (fd = filp->f_pos-2; 1389 fd < fdt->max_fds; 1390 fd++, filp->f_pos++) { 1391 1392 if (!fcheck_files(files, fd)) 1393 continue; 1394 rcu_read_unlock(); 1395 1396 if (proc_fd_fill_cache(filp, dirent, filldir, p, fd) < 0) { 1397 rcu_read_lock(); 1398 break; 1399 } 1400 rcu_read_lock(); 1401 } 1402 rcu_read_unlock(); 1403 put_files_struct(files); 1404 } 1405 out: 1406 put_task_struct(p); 1407 out_no_task: 1408 return retval; 1409 } 1410 1411 static struct file_operations proc_fd_operations = { 1412 .read = generic_read_dir, 1413 .readdir = proc_readfd, 1414 }; 1415 1416 /* 1417 * proc directories can do almost nothing.. 1418 */ 1419 static struct inode_operations proc_fd_inode_operations = { 1420 .lookup = proc_lookupfd, 1421 .setattr = proc_setattr, 1422 }; 1423 1424 static struct dentry *proc_pident_instantiate(struct inode *dir, 1425 struct dentry *dentry, struct task_struct *task, void *ptr) 1426 { 1427 struct pid_entry *p = ptr; 1428 struct inode *inode; 1429 struct proc_inode *ei; 1430 struct dentry *error = ERR_PTR(-EINVAL); 1431 1432 inode = proc_pid_make_inode(dir->i_sb, task); 1433 if (!inode) 1434 goto out; 1435 1436 ei = PROC_I(inode); 1437 inode->i_mode = p->mode; 1438 if (S_ISDIR(inode->i_mode)) 1439 inode->i_nlink = 2; /* Use getattr to fix if necessary */ 1440 if (p->iop) 1441 inode->i_op = p->iop; 1442 if (p->fop) 1443 inode->i_fop = p->fop; 1444 ei->op = p->op; 1445 dentry->d_op = &pid_dentry_operations; 1446 d_add(dentry, inode); 1447 /* Close the race of the process dying before we return the dentry */ 1448 if (pid_revalidate(dentry, NULL)) 1449 error = NULL; 1450 out: 1451 return error; 1452 } 1453 1454 static struct dentry *proc_pident_lookup(struct inode *dir, 1455 struct dentry *dentry, 1456 struct pid_entry *ents, 1457 unsigned int nents) 1458 { 1459 struct inode *inode; 1460 struct dentry *error; 1461 struct task_struct *task = get_proc_task(dir); 1462 struct pid_entry *p, *last; 1463 1464 error = ERR_PTR(-ENOENT); 1465 inode = NULL; 1466 1467 if (!task) 1468 goto out_no_task; 1469 1470 /* 1471 * Yes, it does not scale. And it should not. Don't add 1472 * new entries into /proc/<tgid>/ without very good reasons. 1473 */ 1474 last = &ents[nents - 1]; 1475 for (p = ents; p <= last; p++) { 1476 if (p->len != dentry->d_name.len) 1477 continue; 1478 if (!memcmp(dentry->d_name.name, p->name, p->len)) 1479 break; 1480 } 1481 if (p > last) 1482 goto out; 1483 1484 error = proc_pident_instantiate(dir, dentry, task, p); 1485 out: 1486 put_task_struct(task); 1487 out_no_task: 1488 return error; 1489 } 1490 1491 static int proc_pident_fill_cache(struct file *filp, void *dirent, filldir_t filldir, 1492 struct task_struct *task, struct pid_entry *p) 1493 { 1494 return proc_fill_cache(filp, dirent, filldir, p->name, p->len, 1495 proc_pident_instantiate, task, p); 1496 } 1497 1498 static int proc_pident_readdir(struct file *filp, 1499 void *dirent, filldir_t filldir, 1500 struct pid_entry *ents, unsigned int nents) 1501 { 1502 int i; 1503 int pid; 1504 struct dentry *dentry = filp->f_path.dentry; 1505 struct inode *inode = dentry->d_inode; 1506 struct task_struct *task = get_proc_task(inode); 1507 struct pid_entry *p, *last; 1508 ino_t ino; 1509 int ret; 1510 1511 ret = -ENOENT; 1512 if (!task) 1513 goto out_no_task; 1514 1515 ret = 0; 1516 pid = task->pid; 1517 i = filp->f_pos; 1518 switch (i) { 1519 case 0: 1520 ino = inode->i_ino; 1521 if (filldir(dirent, ".", 1, i, ino, DT_DIR) < 0) 1522 goto out; 1523 i++; 1524 filp->f_pos++; 1525 /* fall through */ 1526 case 1: 1527 ino = parent_ino(dentry); 1528 if (filldir(dirent, "..", 2, i, ino, DT_DIR) < 0) 1529 goto out; 1530 i++; 1531 filp->f_pos++; 1532 /* fall through */ 1533 default: 1534 i -= 2; 1535 if (i >= nents) { 1536 ret = 1; 1537 goto out; 1538 } 1539 p = ents + i; 1540 last = &ents[nents - 1]; 1541 while (p <= last) { 1542 if (proc_pident_fill_cache(filp, dirent, filldir, task, p) < 0) 1543 goto out; 1544 filp->f_pos++; 1545 p++; 1546 } 1547 } 1548 1549 ret = 1; 1550 out: 1551 put_task_struct(task); 1552 out_no_task: 1553 return ret; 1554 } 1555 1556 #ifdef CONFIG_SECURITY 1557 static ssize_t proc_pid_attr_read(struct file * file, char __user * buf, 1558 size_t count, loff_t *ppos) 1559 { 1560 struct inode * inode = file->f_path.dentry->d_inode; 1561 unsigned long page; 1562 ssize_t length; 1563 struct task_struct *task = get_proc_task(inode); 1564 1565 length = -ESRCH; 1566 if (!task) 1567 goto out_no_task; 1568 1569 if (count > PAGE_SIZE) 1570 count = PAGE_SIZE; 1571 length = -ENOMEM; 1572 if (!(page = __get_free_page(GFP_KERNEL))) 1573 goto out; 1574 1575 length = security_getprocattr(task, 1576 (char*)file->f_path.dentry->d_name.name, 1577 (void*)page, count); 1578 if (length >= 0) 1579 length = simple_read_from_buffer(buf, count, ppos, (char *)page, length); 1580 free_page(page); 1581 out: 1582 put_task_struct(task); 1583 out_no_task: 1584 return length; 1585 } 1586 1587 static ssize_t proc_pid_attr_write(struct file * file, const char __user * buf, 1588 size_t count, loff_t *ppos) 1589 { 1590 struct inode * inode = file->f_path.dentry->d_inode; 1591 char *page; 1592 ssize_t length; 1593 struct task_struct *task = get_proc_task(inode); 1594 1595 length = -ESRCH; 1596 if (!task) 1597 goto out_no_task; 1598 if (count > PAGE_SIZE) 1599 count = PAGE_SIZE; 1600 1601 /* No partial writes. */ 1602 length = -EINVAL; 1603 if (*ppos != 0) 1604 goto out; 1605 1606 length = -ENOMEM; 1607 page = (char*)__get_free_page(GFP_USER); 1608 if (!page) 1609 goto out; 1610 1611 length = -EFAULT; 1612 if (copy_from_user(page, buf, count)) 1613 goto out_free; 1614 1615 length = security_setprocattr(task, 1616 (char*)file->f_path.dentry->d_name.name, 1617 (void*)page, count); 1618 out_free: 1619 free_page((unsigned long) page); 1620 out: 1621 put_task_struct(task); 1622 out_no_task: 1623 return length; 1624 } 1625 1626 static struct file_operations proc_pid_attr_operations = { 1627 .read = proc_pid_attr_read, 1628 .write = proc_pid_attr_write, 1629 }; 1630 1631 static struct pid_entry attr_dir_stuff[] = { 1632 REG("current", S_IRUGO|S_IWUGO, pid_attr), 1633 REG("prev", S_IRUGO, pid_attr), 1634 REG("exec", S_IRUGO|S_IWUGO, pid_attr), 1635 REG("fscreate", S_IRUGO|S_IWUGO, pid_attr), 1636 REG("keycreate", S_IRUGO|S_IWUGO, pid_attr), 1637 REG("sockcreate", S_IRUGO|S_IWUGO, pid_attr), 1638 }; 1639 1640 static int proc_attr_dir_readdir(struct file * filp, 1641 void * dirent, filldir_t filldir) 1642 { 1643 return proc_pident_readdir(filp,dirent,filldir, 1644 attr_dir_stuff,ARRAY_SIZE(attr_dir_stuff)); 1645 } 1646 1647 static struct file_operations proc_attr_dir_operations = { 1648 .read = generic_read_dir, 1649 .readdir = proc_attr_dir_readdir, 1650 }; 1651 1652 static struct dentry *proc_attr_dir_lookup(struct inode *dir, 1653 struct dentry *dentry, struct nameidata *nd) 1654 { 1655 return proc_pident_lookup(dir, dentry, 1656 attr_dir_stuff, ARRAY_SIZE(attr_dir_stuff)); 1657 } 1658 1659 static struct inode_operations proc_attr_dir_inode_operations = { 1660 .lookup = proc_attr_dir_lookup, 1661 .getattr = pid_getattr, 1662 .setattr = proc_setattr, 1663 }; 1664 1665 #endif 1666 1667 /* 1668 * /proc/self: 1669 */ 1670 static int proc_self_readlink(struct dentry *dentry, char __user *buffer, 1671 int buflen) 1672 { 1673 char tmp[PROC_NUMBUF]; 1674 sprintf(tmp, "%d", current->tgid); 1675 return vfs_readlink(dentry,buffer,buflen,tmp); 1676 } 1677 1678 static void *proc_self_follow_link(struct dentry *dentry, struct nameidata *nd) 1679 { 1680 char tmp[PROC_NUMBUF]; 1681 sprintf(tmp, "%d", current->tgid); 1682 return ERR_PTR(vfs_follow_link(nd,tmp)); 1683 } 1684 1685 static struct inode_operations proc_self_inode_operations = { 1686 .readlink = proc_self_readlink, 1687 .follow_link = proc_self_follow_link, 1688 }; 1689 1690 /* 1691 * proc base 1692 * 1693 * These are the directory entries in the root directory of /proc 1694 * that properly belong to the /proc filesystem, as they describe 1695 * describe something that is process related. 1696 */ 1697 static struct pid_entry proc_base_stuff[] = { 1698 NOD("self", S_IFLNK|S_IRWXUGO, 1699 &proc_self_inode_operations, NULL, {}), 1700 }; 1701 1702 /* 1703 * Exceptional case: normally we are not allowed to unhash a busy 1704 * directory. In this case, however, we can do it - no aliasing problems 1705 * due to the way we treat inodes. 1706 */ 1707 static int proc_base_revalidate(struct dentry *dentry, struct nameidata *nd) 1708 { 1709 struct inode *inode = dentry->d_inode; 1710 struct task_struct *task = get_proc_task(inode); 1711 if (task) { 1712 put_task_struct(task); 1713 return 1; 1714 } 1715 d_drop(dentry); 1716 return 0; 1717 } 1718 1719 static struct dentry_operations proc_base_dentry_operations = 1720 { 1721 .d_revalidate = proc_base_revalidate, 1722 .d_delete = pid_delete_dentry, 1723 }; 1724 1725 static struct dentry *proc_base_instantiate(struct inode *dir, 1726 struct dentry *dentry, struct task_struct *task, void *ptr) 1727 { 1728 struct pid_entry *p = ptr; 1729 struct inode *inode; 1730 struct proc_inode *ei; 1731 struct dentry *error = ERR_PTR(-EINVAL); 1732 1733 /* Allocate the inode */ 1734 error = ERR_PTR(-ENOMEM); 1735 inode = new_inode(dir->i_sb); 1736 if (!inode) 1737 goto out; 1738 1739 /* Initialize the inode */ 1740 ei = PROC_I(inode); 1741 inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME; 1742 1743 /* 1744 * grab the reference to the task. 1745 */ 1746 ei->pid = get_task_pid(task, PIDTYPE_PID); 1747 if (!ei->pid) 1748 goto out_iput; 1749 1750 inode->i_uid = 0; 1751 inode->i_gid = 0; 1752 inode->i_mode = p->mode; 1753 if (S_ISDIR(inode->i_mode)) 1754 inode->i_nlink = 2; 1755 if (S_ISLNK(inode->i_mode)) 1756 inode->i_size = 64; 1757 if (p->iop) 1758 inode->i_op = p->iop; 1759 if (p->fop) 1760 inode->i_fop = p->fop; 1761 ei->op = p->op; 1762 dentry->d_op = &proc_base_dentry_operations; 1763 d_add(dentry, inode); 1764 error = NULL; 1765 out: 1766 return error; 1767 out_iput: 1768 iput(inode); 1769 goto out; 1770 } 1771 1772 static struct dentry *proc_base_lookup(struct inode *dir, struct dentry *dentry) 1773 { 1774 struct dentry *error; 1775 struct task_struct *task = get_proc_task(dir); 1776 struct pid_entry *p, *last; 1777 1778 error = ERR_PTR(-ENOENT); 1779 1780 if (!task) 1781 goto out_no_task; 1782 1783 /* Lookup the directory entry */ 1784 last = &proc_base_stuff[ARRAY_SIZE(proc_base_stuff) - 1]; 1785 for (p = proc_base_stuff; p <= last; p++) { 1786 if (p->len != dentry->d_name.len) 1787 continue; 1788 if (!memcmp(dentry->d_name.name, p->name, p->len)) 1789 break; 1790 } 1791 if (p > last) 1792 goto out; 1793 1794 error = proc_base_instantiate(dir, dentry, task, p); 1795 1796 out: 1797 put_task_struct(task); 1798 out_no_task: 1799 return error; 1800 } 1801 1802 static int proc_base_fill_cache(struct file *filp, void *dirent, filldir_t filldir, 1803 struct task_struct *task, struct pid_entry *p) 1804 { 1805 return proc_fill_cache(filp, dirent, filldir, p->name, p->len, 1806 proc_base_instantiate, task, p); 1807 } 1808 1809 #ifdef CONFIG_TASK_IO_ACCOUNTING 1810 static int proc_pid_io_accounting(struct task_struct *task, char *buffer) 1811 { 1812 return sprintf(buffer, 1813 "rchar: %llu\n" 1814 "wchar: %llu\n" 1815 "syscr: %llu\n" 1816 "syscw: %llu\n" 1817 "read_bytes: %llu\n" 1818 "write_bytes: %llu\n" 1819 "cancelled_write_bytes: %llu\n", 1820 (unsigned long long)task->rchar, 1821 (unsigned long long)task->wchar, 1822 (unsigned long long)task->syscr, 1823 (unsigned long long)task->syscw, 1824 (unsigned long long)task->ioac.read_bytes, 1825 (unsigned long long)task->ioac.write_bytes, 1826 (unsigned long long)task->ioac.cancelled_write_bytes); 1827 } 1828 #endif 1829 1830 /* 1831 * Thread groups 1832 */ 1833 static struct file_operations proc_task_operations; 1834 static struct inode_operations proc_task_inode_operations; 1835 1836 static struct pid_entry tgid_base_stuff[] = { 1837 DIR("task", S_IRUGO|S_IXUGO, task), 1838 DIR("fd", S_IRUSR|S_IXUSR, fd), 1839 INF("environ", S_IRUSR, pid_environ), 1840 INF("auxv", S_IRUSR, pid_auxv), 1841 INF("status", S_IRUGO, pid_status), 1842 INF("cmdline", S_IRUGO, pid_cmdline), 1843 INF("stat", S_IRUGO, tgid_stat), 1844 INF("statm", S_IRUGO, pid_statm), 1845 REG("maps", S_IRUGO, maps), 1846 #ifdef CONFIG_NUMA 1847 REG("numa_maps", S_IRUGO, numa_maps), 1848 #endif 1849 REG("mem", S_IRUSR|S_IWUSR, mem), 1850 #ifdef CONFIG_SECCOMP 1851 REG("seccomp", S_IRUSR|S_IWUSR, seccomp), 1852 #endif 1853 LNK("cwd", cwd), 1854 LNK("root", root), 1855 LNK("exe", exe), 1856 REG("mounts", S_IRUGO, mounts), 1857 REG("mountstats", S_IRUSR, mountstats), 1858 #ifdef CONFIG_MMU 1859 REG("smaps", S_IRUGO, smaps), 1860 #endif 1861 #ifdef CONFIG_SECURITY 1862 DIR("attr", S_IRUGO|S_IXUGO, attr_dir), 1863 #endif 1864 #ifdef CONFIG_KALLSYMS 1865 INF("wchan", S_IRUGO, pid_wchan), 1866 #endif 1867 #ifdef CONFIG_SCHEDSTATS 1868 INF("schedstat", S_IRUGO, pid_schedstat), 1869 #endif 1870 #ifdef CONFIG_CPUSETS 1871 REG("cpuset", S_IRUGO, cpuset), 1872 #endif 1873 INF("oom_score", S_IRUGO, oom_score), 1874 REG("oom_adj", S_IRUGO|S_IWUSR, oom_adjust), 1875 #ifdef CONFIG_AUDITSYSCALL 1876 REG("loginuid", S_IWUSR|S_IRUGO, loginuid), 1877 #endif 1878 #ifdef CONFIG_FAULT_INJECTION 1879 REG("make-it-fail", S_IRUGO|S_IWUSR, fault_inject), 1880 #endif 1881 #ifdef CONFIG_TASK_IO_ACCOUNTING 1882 INF("io", S_IRUGO, pid_io_accounting), 1883 #endif 1884 }; 1885 1886 static int proc_tgid_base_readdir(struct file * filp, 1887 void * dirent, filldir_t filldir) 1888 { 1889 return proc_pident_readdir(filp,dirent,filldir, 1890 tgid_base_stuff,ARRAY_SIZE(tgid_base_stuff)); 1891 } 1892 1893 static struct file_operations proc_tgid_base_operations = { 1894 .read = generic_read_dir, 1895 .readdir = proc_tgid_base_readdir, 1896 }; 1897 1898 static struct dentry *proc_tgid_base_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd){ 1899 return proc_pident_lookup(dir, dentry, 1900 tgid_base_stuff, ARRAY_SIZE(tgid_base_stuff)); 1901 } 1902 1903 static struct inode_operations proc_tgid_base_inode_operations = { 1904 .lookup = proc_tgid_base_lookup, 1905 .getattr = pid_getattr, 1906 .setattr = proc_setattr, 1907 }; 1908 1909 /** 1910 * proc_flush_task - Remove dcache entries for @task from the /proc dcache. 1911 * 1912 * @task: task that should be flushed. 1913 * 1914 * Looks in the dcache for 1915 * /proc/@pid 1916 * /proc/@tgid/task/@pid 1917 * if either directory is present flushes it and all of it'ts children 1918 * from the dcache. 1919 * 1920 * It is safe and reasonable to cache /proc entries for a task until 1921 * that task exits. After that they just clog up the dcache with 1922 * useless entries, possibly causing useful dcache entries to be 1923 * flushed instead. This routine is proved to flush those useless 1924 * dcache entries at process exit time. 1925 * 1926 * NOTE: This routine is just an optimization so it does not guarantee 1927 * that no dcache entries will exist at process exit time it 1928 * just makes it very unlikely that any will persist. 1929 */ 1930 void proc_flush_task(struct task_struct *task) 1931 { 1932 struct dentry *dentry, *leader, *dir; 1933 char buf[PROC_NUMBUF]; 1934 struct qstr name; 1935 1936 name.name = buf; 1937 name.len = snprintf(buf, sizeof(buf), "%d", task->pid); 1938 dentry = d_hash_and_lookup(proc_mnt->mnt_root, &name); 1939 if (dentry) { 1940 shrink_dcache_parent(dentry); 1941 d_drop(dentry); 1942 dput(dentry); 1943 } 1944 1945 if (thread_group_leader(task)) 1946 goto out; 1947 1948 name.name = buf; 1949 name.len = snprintf(buf, sizeof(buf), "%d", task->tgid); 1950 leader = d_hash_and_lookup(proc_mnt->mnt_root, &name); 1951 if (!leader) 1952 goto out; 1953 1954 name.name = "task"; 1955 name.len = strlen(name.name); 1956 dir = d_hash_and_lookup(leader, &name); 1957 if (!dir) 1958 goto out_put_leader; 1959 1960 name.name = buf; 1961 name.len = snprintf(buf, sizeof(buf), "%d", task->pid); 1962 dentry = d_hash_and_lookup(dir, &name); 1963 if (dentry) { 1964 shrink_dcache_parent(dentry); 1965 d_drop(dentry); 1966 dput(dentry); 1967 } 1968 1969 dput(dir); 1970 out_put_leader: 1971 dput(leader); 1972 out: 1973 return; 1974 } 1975 1976 static struct dentry *proc_pid_instantiate(struct inode *dir, 1977 struct dentry * dentry, 1978 struct task_struct *task, void *ptr) 1979 { 1980 struct dentry *error = ERR_PTR(-ENOENT); 1981 struct inode *inode; 1982 1983 inode = proc_pid_make_inode(dir->i_sb, task); 1984 if (!inode) 1985 goto out; 1986 1987 inode->i_mode = S_IFDIR|S_IRUGO|S_IXUGO; 1988 inode->i_op = &proc_tgid_base_inode_operations; 1989 inode->i_fop = &proc_tgid_base_operations; 1990 inode->i_flags|=S_IMMUTABLE; 1991 inode->i_nlink = 4; 1992 #ifdef CONFIG_SECURITY 1993 inode->i_nlink += 1; 1994 #endif 1995 1996 dentry->d_op = &pid_dentry_operations; 1997 1998 d_add(dentry, inode); 1999 /* Close the race of the process dying before we return the dentry */ 2000 if (pid_revalidate(dentry, NULL)) 2001 error = NULL; 2002 out: 2003 return error; 2004 } 2005 2006 struct dentry *proc_pid_lookup(struct inode *dir, struct dentry * dentry, struct nameidata *nd) 2007 { 2008 struct dentry *result = ERR_PTR(-ENOENT); 2009 struct task_struct *task; 2010 unsigned tgid; 2011 2012 result = proc_base_lookup(dir, dentry); 2013 if (!IS_ERR(result) || PTR_ERR(result) != -ENOENT) 2014 goto out; 2015 2016 tgid = name_to_int(dentry); 2017 if (tgid == ~0U) 2018 goto out; 2019 2020 rcu_read_lock(); 2021 task = find_task_by_pid(tgid); 2022 if (task) 2023 get_task_struct(task); 2024 rcu_read_unlock(); 2025 if (!task) 2026 goto out; 2027 2028 result = proc_pid_instantiate(dir, dentry, task, NULL); 2029 put_task_struct(task); 2030 out: 2031 return result; 2032 } 2033 2034 /* 2035 * Find the first task with tgid >= tgid 2036 * 2037 */ 2038 static struct task_struct *next_tgid(unsigned int tgid) 2039 { 2040 struct task_struct *task; 2041 struct pid *pid; 2042 2043 rcu_read_lock(); 2044 retry: 2045 task = NULL; 2046 pid = find_ge_pid(tgid); 2047 if (pid) { 2048 tgid = pid->nr + 1; 2049 task = pid_task(pid, PIDTYPE_PID); 2050 /* What we to know is if the pid we have find is the 2051 * pid of a thread_group_leader. Testing for task 2052 * being a thread_group_leader is the obvious thing 2053 * todo but there is a window when it fails, due to 2054 * the pid transfer logic in de_thread. 2055 * 2056 * So we perform the straight forward test of seeing 2057 * if the pid we have found is the pid of a thread 2058 * group leader, and don't worry if the task we have 2059 * found doesn't happen to be a thread group leader. 2060 * As we don't care in the case of readdir. 2061 */ 2062 if (!task || !has_group_leader_pid(task)) 2063 goto retry; 2064 get_task_struct(task); 2065 } 2066 rcu_read_unlock(); 2067 return task; 2068 } 2069 2070 #define TGID_OFFSET (FIRST_PROCESS_ENTRY + ARRAY_SIZE(proc_base_stuff)) 2071 2072 static int proc_pid_fill_cache(struct file *filp, void *dirent, filldir_t filldir, 2073 struct task_struct *task, int tgid) 2074 { 2075 char name[PROC_NUMBUF]; 2076 int len = snprintf(name, sizeof(name), "%d", tgid); 2077 return proc_fill_cache(filp, dirent, filldir, name, len, 2078 proc_pid_instantiate, task, NULL); 2079 } 2080 2081 /* for the /proc/ directory itself, after non-process stuff has been done */ 2082 int proc_pid_readdir(struct file * filp, void * dirent, filldir_t filldir) 2083 { 2084 unsigned int nr = filp->f_pos - FIRST_PROCESS_ENTRY; 2085 struct task_struct *reaper = get_proc_task(filp->f_path.dentry->d_inode); 2086 struct task_struct *task; 2087 int tgid; 2088 2089 if (!reaper) 2090 goto out_no_task; 2091 2092 for (; nr < ARRAY_SIZE(proc_base_stuff); filp->f_pos++, nr++) { 2093 struct pid_entry *p = &proc_base_stuff[nr]; 2094 if (proc_base_fill_cache(filp, dirent, filldir, reaper, p) < 0) 2095 goto out; 2096 } 2097 2098 tgid = filp->f_pos - TGID_OFFSET; 2099 for (task = next_tgid(tgid); 2100 task; 2101 put_task_struct(task), task = next_tgid(tgid + 1)) { 2102 tgid = task->pid; 2103 filp->f_pos = tgid + TGID_OFFSET; 2104 if (proc_pid_fill_cache(filp, dirent, filldir, task, tgid) < 0) { 2105 put_task_struct(task); 2106 goto out; 2107 } 2108 } 2109 filp->f_pos = PID_MAX_LIMIT + TGID_OFFSET; 2110 out: 2111 put_task_struct(reaper); 2112 out_no_task: 2113 return 0; 2114 } 2115 2116 /* 2117 * Tasks 2118 */ 2119 static struct pid_entry tid_base_stuff[] = { 2120 DIR("fd", S_IRUSR|S_IXUSR, fd), 2121 INF("environ", S_IRUSR, pid_environ), 2122 INF("auxv", S_IRUSR, pid_auxv), 2123 INF("status", S_IRUGO, pid_status), 2124 INF("cmdline", S_IRUGO, pid_cmdline), 2125 INF("stat", S_IRUGO, tid_stat), 2126 INF("statm", S_IRUGO, pid_statm), 2127 REG("maps", S_IRUGO, maps), 2128 #ifdef CONFIG_NUMA 2129 REG("numa_maps", S_IRUGO, numa_maps), 2130 #endif 2131 REG("mem", S_IRUSR|S_IWUSR, mem), 2132 #ifdef CONFIG_SECCOMP 2133 REG("seccomp", S_IRUSR|S_IWUSR, seccomp), 2134 #endif 2135 LNK("cwd", cwd), 2136 LNK("root", root), 2137 LNK("exe", exe), 2138 REG("mounts", S_IRUGO, mounts), 2139 #ifdef CONFIG_MMU 2140 REG("smaps", S_IRUGO, smaps), 2141 #endif 2142 #ifdef CONFIG_SECURITY 2143 DIR("attr", S_IRUGO|S_IXUGO, attr_dir), 2144 #endif 2145 #ifdef CONFIG_KALLSYMS 2146 INF("wchan", S_IRUGO, pid_wchan), 2147 #endif 2148 #ifdef CONFIG_SCHEDSTATS 2149 INF("schedstat", S_IRUGO, pid_schedstat), 2150 #endif 2151 #ifdef CONFIG_CPUSETS 2152 REG("cpuset", S_IRUGO, cpuset), 2153 #endif 2154 INF("oom_score", S_IRUGO, oom_score), 2155 REG("oom_adj", S_IRUGO|S_IWUSR, oom_adjust), 2156 #ifdef CONFIG_AUDITSYSCALL 2157 REG("loginuid", S_IWUSR|S_IRUGO, loginuid), 2158 #endif 2159 #ifdef CONFIG_FAULT_INJECTION 2160 REG("make-it-fail", S_IRUGO|S_IWUSR, fault_inject), 2161 #endif 2162 }; 2163 2164 static int proc_tid_base_readdir(struct file * filp, 2165 void * dirent, filldir_t filldir) 2166 { 2167 return proc_pident_readdir(filp,dirent,filldir, 2168 tid_base_stuff,ARRAY_SIZE(tid_base_stuff)); 2169 } 2170 2171 static struct dentry *proc_tid_base_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd){ 2172 return proc_pident_lookup(dir, dentry, 2173 tid_base_stuff, ARRAY_SIZE(tid_base_stuff)); 2174 } 2175 2176 static struct file_operations proc_tid_base_operations = { 2177 .read = generic_read_dir, 2178 .readdir = proc_tid_base_readdir, 2179 }; 2180 2181 static struct inode_operations proc_tid_base_inode_operations = { 2182 .lookup = proc_tid_base_lookup, 2183 .getattr = pid_getattr, 2184 .setattr = proc_setattr, 2185 }; 2186 2187 static struct dentry *proc_task_instantiate(struct inode *dir, 2188 struct dentry *dentry, struct task_struct *task, void *ptr) 2189 { 2190 struct dentry *error = ERR_PTR(-ENOENT); 2191 struct inode *inode; 2192 inode = proc_pid_make_inode(dir->i_sb, task); 2193 2194 if (!inode) 2195 goto out; 2196 inode->i_mode = S_IFDIR|S_IRUGO|S_IXUGO; 2197 inode->i_op = &proc_tid_base_inode_operations; 2198 inode->i_fop = &proc_tid_base_operations; 2199 inode->i_flags|=S_IMMUTABLE; 2200 inode->i_nlink = 3; 2201 #ifdef CONFIG_SECURITY 2202 inode->i_nlink += 1; 2203 #endif 2204 2205 dentry->d_op = &pid_dentry_operations; 2206 2207 d_add(dentry, inode); 2208 /* Close the race of the process dying before we return the dentry */ 2209 if (pid_revalidate(dentry, NULL)) 2210 error = NULL; 2211 out: 2212 return error; 2213 } 2214 2215 static struct dentry *proc_task_lookup(struct inode *dir, struct dentry * dentry, struct nameidata *nd) 2216 { 2217 struct dentry *result = ERR_PTR(-ENOENT); 2218 struct task_struct *task; 2219 struct task_struct *leader = get_proc_task(dir); 2220 unsigned tid; 2221 2222 if (!leader) 2223 goto out_no_task; 2224 2225 tid = name_to_int(dentry); 2226 if (tid == ~0U) 2227 goto out; 2228 2229 rcu_read_lock(); 2230 task = find_task_by_pid(tid); 2231 if (task) 2232 get_task_struct(task); 2233 rcu_read_unlock(); 2234 if (!task) 2235 goto out; 2236 if (leader->tgid != task->tgid) 2237 goto out_drop_task; 2238 2239 result = proc_task_instantiate(dir, dentry, task, NULL); 2240 out_drop_task: 2241 put_task_struct(task); 2242 out: 2243 put_task_struct(leader); 2244 out_no_task: 2245 return result; 2246 } 2247 2248 /* 2249 * Find the first tid of a thread group to return to user space. 2250 * 2251 * Usually this is just the thread group leader, but if the users 2252 * buffer was too small or there was a seek into the middle of the 2253 * directory we have more work todo. 2254 * 2255 * In the case of a short read we start with find_task_by_pid. 2256 * 2257 * In the case of a seek we start with the leader and walk nr 2258 * threads past it. 2259 */ 2260 static struct task_struct *first_tid(struct task_struct *leader, 2261 int tid, int nr) 2262 { 2263 struct task_struct *pos; 2264 2265 rcu_read_lock(); 2266 /* Attempt to start with the pid of a thread */ 2267 if (tid && (nr > 0)) { 2268 pos = find_task_by_pid(tid); 2269 if (pos && (pos->group_leader == leader)) 2270 goto found; 2271 } 2272 2273 /* If nr exceeds the number of threads there is nothing todo */ 2274 pos = NULL; 2275 if (nr && nr >= get_nr_threads(leader)) 2276 goto out; 2277 2278 /* If we haven't found our starting place yet start 2279 * with the leader and walk nr threads forward. 2280 */ 2281 for (pos = leader; nr > 0; --nr) { 2282 pos = next_thread(pos); 2283 if (pos == leader) { 2284 pos = NULL; 2285 goto out; 2286 } 2287 } 2288 found: 2289 get_task_struct(pos); 2290 out: 2291 rcu_read_unlock(); 2292 return pos; 2293 } 2294 2295 /* 2296 * Find the next thread in the thread list. 2297 * Return NULL if there is an error or no next thread. 2298 * 2299 * The reference to the input task_struct is released. 2300 */ 2301 static struct task_struct *next_tid(struct task_struct *start) 2302 { 2303 struct task_struct *pos = NULL; 2304 rcu_read_lock(); 2305 if (pid_alive(start)) { 2306 pos = next_thread(start); 2307 if (thread_group_leader(pos)) 2308 pos = NULL; 2309 else 2310 get_task_struct(pos); 2311 } 2312 rcu_read_unlock(); 2313 put_task_struct(start); 2314 return pos; 2315 } 2316 2317 static int proc_task_fill_cache(struct file *filp, void *dirent, filldir_t filldir, 2318 struct task_struct *task, int tid) 2319 { 2320 char name[PROC_NUMBUF]; 2321 int len = snprintf(name, sizeof(name), "%d", tid); 2322 return proc_fill_cache(filp, dirent, filldir, name, len, 2323 proc_task_instantiate, task, NULL); 2324 } 2325 2326 /* for the /proc/TGID/task/ directories */ 2327 static int proc_task_readdir(struct file * filp, void * dirent, filldir_t filldir) 2328 { 2329 struct dentry *dentry = filp->f_path.dentry; 2330 struct inode *inode = dentry->d_inode; 2331 struct task_struct *leader = NULL; 2332 struct task_struct *task; 2333 int retval = -ENOENT; 2334 ino_t ino; 2335 int tid; 2336 unsigned long pos = filp->f_pos; /* avoiding "long long" filp->f_pos */ 2337 2338 task = get_proc_task(inode); 2339 if (!task) 2340 goto out_no_task; 2341 rcu_read_lock(); 2342 if (pid_alive(task)) { 2343 leader = task->group_leader; 2344 get_task_struct(leader); 2345 } 2346 rcu_read_unlock(); 2347 put_task_struct(task); 2348 if (!leader) 2349 goto out_no_task; 2350 retval = 0; 2351 2352 switch (pos) { 2353 case 0: 2354 ino = inode->i_ino; 2355 if (filldir(dirent, ".", 1, pos, ino, DT_DIR) < 0) 2356 goto out; 2357 pos++; 2358 /* fall through */ 2359 case 1: 2360 ino = parent_ino(dentry); 2361 if (filldir(dirent, "..", 2, pos, ino, DT_DIR) < 0) 2362 goto out; 2363 pos++; 2364 /* fall through */ 2365 } 2366 2367 /* f_version caches the tgid value that the last readdir call couldn't 2368 * return. lseek aka telldir automagically resets f_version to 0. 2369 */ 2370 tid = filp->f_version; 2371 filp->f_version = 0; 2372 for (task = first_tid(leader, tid, pos - 2); 2373 task; 2374 task = next_tid(task), pos++) { 2375 tid = task->pid; 2376 if (proc_task_fill_cache(filp, dirent, filldir, task, tid) < 0) { 2377 /* returning this tgid failed, save it as the first 2378 * pid for the next readir call */ 2379 filp->f_version = tid; 2380 put_task_struct(task); 2381 break; 2382 } 2383 } 2384 out: 2385 filp->f_pos = pos; 2386 put_task_struct(leader); 2387 out_no_task: 2388 return retval; 2389 } 2390 2391 static int proc_task_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat) 2392 { 2393 struct inode *inode = dentry->d_inode; 2394 struct task_struct *p = get_proc_task(inode); 2395 generic_fillattr(inode, stat); 2396 2397 if (p) { 2398 rcu_read_lock(); 2399 stat->nlink += get_nr_threads(p); 2400 rcu_read_unlock(); 2401 put_task_struct(p); 2402 } 2403 2404 return 0; 2405 } 2406 2407 static struct inode_operations proc_task_inode_operations = { 2408 .lookup = proc_task_lookup, 2409 .getattr = proc_task_getattr, 2410 .setattr = proc_setattr, 2411 }; 2412 2413 static struct file_operations proc_task_operations = { 2414 .read = generic_read_dir, 2415 .readdir = proc_task_readdir, 2416 }; 2417