server/change.c

   1 /*
   2  * Server-side change notification management
   3  *
   4  * Copyright (C) 1998 Alexandre Julliard
   5  * Copyright (C) 2006 Mike McCormack
   6  *
   7  * This library is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU Lesser General Public
   9  * License as published by the Free Software Foundation; either
  10  * version 2.1 of the License, or (at your option) any later version.
  11  *
  12  * This library is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * Lesser General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Lesser General Public
  18  * License along with this library; if not, write to the Free Software
  19  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  20  */
  21
  22 #include "config.h"
  23 #include "wine/port.h"
  24
  25 #include <assert.h>
  26 #include <fcntl.h>
  27 #include <stdio.h>
  28 #include <stdlib.h>
  29 #include <signal.h>
  30 #include <sys/stat.h>
  31 #include <sys/types.h>
  32 #include <limits.h>
  33 #include <dirent.h>
  34 #include <errno.h>
  35 #ifdef HAVE_SYS_ERRNO_H
  36 #include <sys/errno.h>
  37 #endif
  38
  39 #include "ntstatus.h"
  40 #define WIN32_NO_STATUS
  41 #include "windef.h"
  42
  43 #include "file.h"
  44 #include "handle.h"
  45 #include "thread.h"
  46 #include "request.h"
  47 #include "winternl.h"
  48
  49 /* dnotify support */
  50
  51 #ifdef linux
  52 #ifndef F_NOTIFY
  53 #define F_NOTIFY 1026
  54 #define DN_ACCESS       0x00000001      /* File accessed */
  55 #define DN_MODIFY       0x00000002      /* File modified */
  56 #define DN_CREATE       0x00000004      /* File created */
  57 #define DN_DELETE       0x00000008      /* File removed */
  58 #define DN_RENAME       0x00000010      /* File renamed */
  59 #define DN_ATTRIB       0x00000020      /* File changed attibutes */
  60 #define DN_MULTISHOT    0x80000000      /* Don't remove notifier */
  61 #endif
  62 #endif
  63
  64 /* inotify support */
  65
  66 #if defined(__linux__) && defined(__i386__)
  67
  68 #define SYS_inotify_init        291
  69 #define SYS_inotify_add_watch   292
  70 #define SYS_inotify_rm_watch    293
  71
  72 struct inotify_event {
  73     int           wd;
  74     unsigned int  mask;
  75     unsigned int  cookie;
  76     unsigned int  len;
  77     char          name[1];
  78 };
  79
  80 #define IN_ACCESS        0x00000001
  81 #define IN_MODIFY        0x00000002
  82 #define IN_ATTRIB        0x00000004
  83 #define IN_CLOSE_WRITE   0x00000008
  84 #define IN_CLOSE_NOWRITE 0x00000010
  85 #define IN_OPEN          0x00000020
  86 #define IN_MOVED_FROM    0x00000040
  87 #define IN_MOVED_TO      0x00000080
  88 #define IN_CREATE        0x00000100
  89 #define IN_DELETE        0x00000200
  90 #define IN_DELETE_SELF   0x00000400
  91
  92 static inline int inotify_init( void )
  93 {
  94     int ret;
  95     __asm__ __volatile__( "int $0x80"
  96                           : "=a" (ret)
  97                           : "0" (SYS_inotify_init));
  98     if (ret<0) { errno = -ret; ret = -1; }
  99     return ret;
 100 }
 101
 102 static inline int inotify_add_watch( int fd, const char *name, unsigned int mask )
 103 {
 104     int ret;
 105     __asm__ __volatile__( "pushl %%ebx;\n\t"
 106                           "movl %2,%%ebx;\n\t"
 107                           "int $0x80;\n\t"
 108                           "popl %%ebx"
 109                           : "=a" (ret) : "0" (SYS_inotify_add_watch),
 110                             "r" (fd), "c" (name), "d" (mask) );
 111     if (ret<0) { errno = -ret; ret = -1; }
 112     return ret;
 113 }
 114
 115 static inline int inotify_remove_watch( int fd, int wd )
 116 {
 117     int ret;
 118     __asm__ __volatile__( "pushl %%ebx;\n\t"
 119                           "movl %2,%%ebx;\n\t"
 120                           "int $0x80;\n\t"
 121                           "popl %%ebx"
 122                           : "=a" (ret) : "0" (SYS_inotify_rm_watch),
 123                             "r" (fd), "c" (wd) );
 124     if (ret<0) { errno = -ret; ret = -1; }
 125     return ret;
 126 }
 127
 128 #define USE_INOTIFY
 129
 130 #endif
 131
 132 struct inode;
 133
 134 static void free_inode( struct inode *inode );
 135
 136 static struct fd *inotify_fd;
 137
 138 struct change_record {
 139     struct list entry;
 140     int action;
 141     int len;
 142     char name[1];
 143 };
 144
 145 struct dir
 146 {
 147     struct object  obj;      /* object header */
 148     struct fd     *fd;       /* file descriptor to the directory */
 149     struct list    entry;    /* entry in global change notifications list */
 150     struct event  *event;
 151     unsigned int   filter;   /* notification filter */
 152     int            notified; /* SIGIO counter */
 153     int            want_data; /* return change data */
 154     long           signaled; /* the file changed */
 155     int            subtree;  /* do we want to watch subdirectories? */
 156     struct list    change_q; /* change readers */
 157     struct list    change_records;   /* data for the change */
 158     struct list    in_entry; /* entry in the inode dirs list */
 159     struct inode  *inode;    /* inode of the associated directory */
 160 };
 161
 162 static struct fd *dir_get_fd( struct object *obj );
 163 static unsigned int dir_map_access( struct object *obj, unsigned int access );
 164 static void dir_dump( struct object *obj, int verbose );
 165 static void dir_destroy( struct object *obj );
 166 static int dir_signaled( struct object *obj, struct thread *thread );
 167
 168 static const struct object_ops dir_ops =
 169 {
 170     sizeof(struct dir),       /* size */
 171     dir_dump,                 /* dump */
 172     add_queue,                /* add_queue */
 173     remove_queue,             /* remove_queue */
 174     dir_signaled,             /* signaled */
 175     no_satisfied,             /* satisfied */
 176     no_signal,                /* signal */
 177     dir_get_fd,               /* get_fd */
 178     dir_map_access,           /* map_access */
 179     no_lookup_name,           /* lookup_name */
 180     no_close_handle,          /* close_handle */
 181     dir_destroy               /* destroy */
 182 };
 183
 184 static int dir_get_poll_events( struct fd *fd );
 185 static int dir_get_info( struct fd *fd );
 186 static void dir_cancel_async( struct fd *fd );
 187
 188 static const struct fd_ops dir_fd_ops =
 189 {
 190     dir_get_poll_events,      /* get_poll_events */
 191     default_poll_event,       /* poll_event */
 192     no_flush,                 /* flush */
 193     dir_get_info,             /* get_file_info */
 194     default_fd_queue_async,   /* queue_async */
 195     dir_cancel_async          /* cancel_async */
 196 };
 197
 198 static struct list change_list = LIST_INIT(change_list);
 199
 200 static void dnotify_adjust_changes( struct dir *dir )
 201 {
 202 #if defined(F_SETSIG) && defined(F_NOTIFY)
 203     int fd = get_unix_fd( dir->fd );
 204     unsigned int filter = dir->filter;
 205     unsigned int val;
 206     if ( 0 > fcntl( fd, F_SETSIG, SIGIO) )
 207         return;
 208
 209     val = DN_MULTISHOT;
 210     if (filter & FILE_NOTIFY_CHANGE_FILE_NAME)
 211         val |= DN_RENAME | DN_DELETE | DN_CREATE;
 212     if (filter & FILE_NOTIFY_CHANGE_DIR_NAME)
 213         val |= DN_RENAME | DN_DELETE | DN_CREATE;
 214     if (filter & FILE_NOTIFY_CHANGE_ATTRIBUTES)
 215         val |= DN_ATTRIB;
 216     if (filter & FILE_NOTIFY_CHANGE_SIZE)
 217         val |= DN_MODIFY;
 218     if (filter & FILE_NOTIFY_CHANGE_LAST_WRITE)
 219         val |= DN_MODIFY;
 220     if (filter & FILE_NOTIFY_CHANGE_LAST_ACCESS)
 221         val |= DN_ACCESS;
 222     if (filter & FILE_NOTIFY_CHANGE_CREATION)
 223         val |= DN_CREATE;
 224     if (filter & FILE_NOTIFY_CHANGE_SECURITY)
 225         val |= DN_ATTRIB;
 226     fcntl( fd, F_NOTIFY, val );
 227 #endif
 228 }
 229
 230 /* insert change in the global list */
 231 static inline void insert_change( struct dir *dir )
 232 {
 233     sigset_t sigset;
 234
 235     sigemptyset( &sigset );
 236     sigaddset( &sigset, SIGIO );
 237     sigprocmask( SIG_BLOCK, &sigset, NULL );
 238     list_add_head( &change_list, &dir->entry );
 239     sigprocmask( SIG_UNBLOCK, &sigset, NULL );
 240 }
 241
 242 /* remove change from the global list */
 243 static inline void remove_change( struct dir *dir )
 244 {
 245     sigset_t sigset;
 246
 247     sigemptyset( &sigset );
 248     sigaddset( &sigset, SIGIO );
 249     sigprocmask( SIG_BLOCK, &sigset, NULL );
 250     list_remove( &dir->entry );
 251     sigprocmask( SIG_UNBLOCK, &sigset, NULL );
 252 }
 253
 254 static void dir_dump( struct object *obj, int verbose )
 255 {
 256     struct dir *dir = (struct dir *)obj;
 257     assert( obj->ops == &dir_ops );
 258     fprintf( stderr, "Dirfile fd=%p event=%p filter=%08x\n",
 259              dir->fd, dir->event, dir->filter );
 260 }
 261
 262 static int dir_signaled( struct object *obj, struct thread *thread )
 263 {
 264     struct dir *dir = (struct dir *)obj;
 265     assert (obj->ops == &dir_ops);
 266     return (dir->event == NULL) && dir->signaled;
 267 }
 268
 269 /* enter here directly from SIGIO signal handler */
 270 void do_change_notify( int unix_fd )
 271 {
 272     struct dir *dir;
 273
 274     /* FIXME: this is O(n) ... probably can be improved */
 275     LIST_FOR_EACH_ENTRY( dir, &change_list, struct dir, entry )
 276     {
 277         if (get_unix_fd( dir->fd ) != unix_fd) continue;
 278         interlocked_xchg_add( &dir->notified, 1 );
 279         break;
 280     }
 281 }
 282
 283 static void dir_signal_changed( struct dir *dir )
 284 {
 285     if (dir->event)
 286         set_event( dir->event );
 287     else
 288         wake_up( &dir->obj, 0 );
 289 }
 290
 291 /* SIGIO callback, called synchronously with the poll loop */
 292 void sigio_callback(void)
 293 {
 294     struct dir *dir;
 295
 296     LIST_FOR_EACH_ENTRY( dir, &change_list, struct dir, entry )
 297     {
 298         long count = interlocked_xchg( &dir->notified, 0 );
 299         if (count)
 300         {
 301             dir->signaled += count;
 302             if (dir->signaled == count)  /* was it 0? */
 303                 dir_signal_changed( dir );
 304         }
 305     }
 306 }
 307
 308 static struct fd *dir_get_fd( struct object *obj )
 309 {
 310     struct dir *dir = (struct dir *)obj;
 311     assert( obj->ops == &dir_ops );
 312     return (struct fd *)grab_object( dir->fd );
 313 }
 314
 315 static unsigned int dir_map_access( struct object *obj, unsigned int access )
 316 {
 317     if (access & GENERIC_READ)    access |= FILE_GENERIC_READ;
 318     if (access & GENERIC_WRITE)   access |= FILE_GENERIC_WRITE;
 319     if (access & GENERIC_EXECUTE) access |= FILE_GENERIC_EXECUTE;
 320     if (access & GENERIC_ALL)     access |= FILE_ALL_ACCESS;
 321     return access & ~(GENERIC_READ | GENERIC_WRITE | GENERIC_EXECUTE | GENERIC_ALL);
 322 }
 323
 324 static struct change_record *get_first_change_record( struct dir *dir )
 325 {
 326     struct list *ptr = list_head( &dir->change_records );
 327     if (!ptr) return NULL;
 328     list_remove( ptr );
 329     return LIST_ENTRY( ptr, struct change_record, entry );
 330 }
 331
 332 static void dir_destroy( struct object *obj )
 333 {
 334     struct change_record *record;
 335     struct dir *dir = (struct dir *)obj;
 336     assert (obj->ops == &dir_ops);
 337
 338     if (dir->filter)
 339         remove_change( dir );
 340
 341     if (dir->inode)
 342     {
 343         list_remove( &dir->in_entry );
 344         free_inode( dir->inode );
 345     }
 346
 347     async_terminate_queue( &dir->change_q, STATUS_CANCELLED );
 348     while ((record = get_first_change_record( dir ))) free( record );
 349
 350     if (dir->event)
 351     {
 352         set_event( dir->event );
 353         release_object( dir->event );
 354     }
 355     release_object( dir->fd );
 356
 357     if (inotify_fd && list_empty( &change_list ))
 358     {
 359         release_object( inotify_fd );
 360         inotify_fd = NULL;
 361     }
 362 }
 363
 364 static struct dir *
 365 get_dir_obj( struct process *process, obj_handle_t handle, unsigned int access )
 366 {
 367     return (struct dir *)get_handle_obj( process, handle, access, &dir_ops );
 368 }
 369
 370 static int dir_get_poll_events( struct fd *fd )
 371 {
 372     return 0;
 373 }
 374
 375 static int dir_get_info( struct fd *fd )
 376 {
 377     return 0;
 378 }
 379
 380 static void dir_cancel_async( struct fd *fd )
 381 {
 382     struct dir *dir = (struct dir *) get_fd_user( fd );
 383     async_terminate_queue( &dir->change_q, STATUS_CANCELLED );
 384 }
 385
 386
 387 #ifdef USE_INOTIFY
 388
 389 #define HASH_SIZE 31
 390
 391 struct inode {
 392     struct list ch_entry;    /* entry in the children list */
 393     struct list children;    /* children of this inode */
 394     struct inode *parent;    /* parent of this inode */
 395     struct list dirs;        /* directory handles watching this inode */
 396     struct list ino_entry;   /* entry in the inode hash */
 397     struct list wd_entry;    /* entry in the watch descriptor hash */
 398     dev_t dev;               /* device number */
 399     ino_t ino;               /* device's inode number */
 400     int wd;                  /* inotify's watch descriptor */
 401     char *name;              /* basename name of the inode */
 402 };
 403
 404 struct list inode_hash[ HASH_SIZE ];
 405 struct list wd_hash[ HASH_SIZE ];
 406
 407 static int inotify_add_dir( char *path, unsigned int filter );
 408
 409 static struct inode *inode_from_wd( int wd )
 410 {
 411     struct list *bucket = &wd_hash[ wd % HASH_SIZE ];
 412     struct inode *inode;
 413
 414     LIST_FOR_EACH_ENTRY( inode, bucket, struct inode, wd_entry )
 415         if (inode->wd == wd)
 416             return inode;
 417
 418     return NULL;
 419 }
 420
 421 static inline struct list *get_hash_list( dev_t dev, ino_t ino )
 422 {
 423     return &inode_hash[ (ino ^ dev) % HASH_SIZE ];
 424 }
 425
 426 static struct inode *find_inode( dev_t dev, ino_t ino )
 427 {
 428     struct list *bucket = get_hash_list( dev, ino );
 429     struct inode *inode;
 430
 431     LIST_FOR_EACH_ENTRY( inode, bucket, struct inode, ino_entry )
 432         if (inode->ino == ino && inode->dev == dev)
 433              return inode;
 434
 435     return NULL;
 436 }
 437
 438 static struct inode *create_inode( dev_t dev, ino_t ino )
 439 {
 440     struct inode *inode;
 441
 442     inode = malloc( sizeof *inode );
 443     if (inode)
 444     {
 445         list_init( &inode->children );
 446         list_init( &inode->dirs );
 447         inode->ino = ino;
 448         inode->dev = dev;
 449         inode->wd = -1;
 450         inode->parent = NULL;
 451         inode->name = NULL;
 452         list_add_tail( get_hash_list( dev, ino ), &inode->ino_entry );
 453     }
 454     return inode;
 455 }
 456
 457 static struct inode *get_inode( dev_t dev, ino_t ino )
 458 {
 459     struct inode *inode;
 460
 461     inode = find_inode( dev, ino );
 462     if (inode)
 463         return inode;
 464     return create_inode( dev, ino );
 465 }
 466
 467 static void inode_set_wd( struct inode *inode, int wd )
 468 {
 469     if (inode->wd != -1)
 470         list_remove( &inode->wd_entry );
 471     inode->wd = wd;
 472     list_add_tail( &wd_hash[ wd % HASH_SIZE ], &inode->wd_entry );
 473 }
 474
 475 static void inode_set_name( struct inode *inode, const char *name )
 476 {
 477     if (inode->name)
 478         free (inode->name);
 479     inode->name = name ? strdup( name ) : NULL;
 480 }
 481
 482 static void free_inode( struct inode *inode )
 483 {
 484     int subtree = 0, watches = 0;
 485     struct dir *dir;
 486
 487     LIST_FOR_EACH_ENTRY( dir, &inode->dirs, struct dir, in_entry )
 488     {
 489         subtree |= dir->subtree;
 490         watches++;
 491     }
 492
 493     if (!subtree && !inode->parent)
 494     {
 495         struct inode *tmp, *next;
 496         LIST_FOR_EACH_ENTRY_SAFE( tmp, next, &inode->children,
 497                                   struct inode, ch_entry )
 498         {
 499             assert( tmp != inode );
 500             assert( tmp->parent == inode );
 501             free_inode( tmp );
 502         }
 503     }
 504
 505     if (watches)
 506         return;
 507
 508     if (inode->parent)
 509         list_remove( &inode->ch_entry );
 510
 511     if (inode->wd != -1)
 512     {
 513         inotify_remove_watch( get_unix_fd( inotify_fd ), inode->wd );
 514         list_remove( &inode->wd_entry );
 515     }
 516     list_remove( &inode->ino_entry );
 517
 518     free( inode->name );
 519     free( inode );
 520 }
 521
 522 static struct inode *inode_add( struct inode *parent,
 523                                 dev_t dev, ino_t ino, const char *name )
 524 {
 525     struct inode *inode;
 526
 527     inode = get_inode( dev, ino );
 528     if (!inode)
 529         return NULL;
 530
 531     if (!inode->parent)
 532     {
 533         list_add_tail( &parent->children, &inode->ch_entry );
 534         inode->parent = parent;
 535         assert( inode != parent );
 536     }
 537     inode_set_name( inode, name );
 538
 539     return inode;
 540 }
 541
 542 static struct inode *inode_from_name( struct inode *inode, const char *name )
 543 {
 544     struct inode *i;
 545
 546     LIST_FOR_EACH_ENTRY( i, &inode->children, struct inode, ch_entry )
 547         if (i->name && !strcmp( i->name, name ))
 548             return i;
 549     return NULL;
 550 }
 551
 552 static int inotify_get_poll_events( struct fd *fd );
 553 static void inotify_poll_event( struct fd *fd, int event );
 554 static int inotify_get_info( struct fd *fd );
 555
 556 static const struct fd_ops inotify_fd_ops =
 557 {
 558     inotify_get_poll_events,  /* get_poll_events */
 559     inotify_poll_event,       /* poll_event */
 560     no_flush,                 /* flush */
 561     inotify_get_info,         /* get_file_info */
 562     default_fd_queue_async,   /* queue_async */
 563     default_fd_cancel_async,  /* cancel_async */
 564 };
 565
 566 static int inotify_get_poll_events( struct fd *fd )
 567 {
 568     return POLLIN;
 569 }
 570
 571 static void inotify_do_change_notify( struct dir *dir, unsigned int action,
 572                                       const char *relpath )
 573 {
 574     struct change_record *record;
 575
 576     assert( dir->obj.ops == &dir_ops );
 577
 578     if (dir->want_data)
 579     {
 580         size_t len = strlen(relpath);
 581         record = malloc( offsetof(struct change_record, name[len]) );
 582         if (!record)
 583             return;
 584
 585         record->action = action;
 586         memcpy( record->name, relpath, len );
 587         record->len = len;
 588
 589         list_add_tail( &dir->change_records, &record->entry );
 590     }
 591
 592     if (!list_empty( &dir->change_q ))
 593         async_terminate_head( &dir->change_q, STATUS_ALERTED );
 594 }
 595
 596 static unsigned int filter_from_event( struct inotify_event *ie )
 597 {
 598     unsigned int filter = 0;
 599
 600     if (ie->mask & (IN_MOVED_FROM | IN_MOVED_TO | IN_DELETE | IN_CREATE))
 601         filter |= FILE_NOTIFY_CHANGE_FILE_NAME | FILE_NOTIFY_CHANGE_DIR_NAME;
 602     if (ie->mask & IN_MODIFY)
 603         filter |= FILE_NOTIFY_CHANGE_SIZE | FILE_NOTIFY_CHANGE_LAST_WRITE;
 604     if (ie->mask & IN_ATTRIB)
 605         filter |= FILE_NOTIFY_CHANGE_ATTRIBUTES | FILE_NOTIFY_CHANGE_SECURITY;
 606     if (ie->mask & IN_ACCESS)
 607         filter |= FILE_NOTIFY_CHANGE_LAST_ACCESS;
 608     if (ie->mask & IN_CREATE)
 609         filter |= FILE_NOTIFY_CHANGE_CREATION;
 610
 611     return filter;
 612 }
 613
 614 /* scan up the parent directories for watches */
 615 static unsigned int filter_from_inode( struct inode *inode, int is_parent )
 616 {
 617     unsigned int filter = 0;
 618     struct dir *dir;
 619
 620     /* combine filters from parents watching subtrees */
 621     while (inode)
 622     {
 623         LIST_FOR_EACH_ENTRY( dir, &inode->dirs, struct dir, in_entry )
 624             if (dir->subtree || !is_parent)
 625                 filter |= dir->filter;
 626         is_parent = 1;
 627         inode = inode->parent;
 628     }
 629
 630     return filter;
 631 }
 632
 633 static char *inode_get_path( struct inode *inode, int sz )
 634 {
 635     struct list *head;
 636     char *path;
 637     int len;
 638
 639     if (!inode)
 640         return NULL;
 641
 642     head = list_head( &inode->dirs );
 643     if (head)
 644     {
 645         int unix_fd = get_unix_fd( LIST_ENTRY( head, struct dir, in_entry )->fd );
 646         path = malloc ( 32 + sz );
 647         if (path)
 648             sprintf( path, "/proc/self/fd/%u/", unix_fd );
 649         return path;
 650     }
 651
 652     if (!inode->name)
 653         return NULL;
 654
 655     len = strlen( inode->name );
 656     path = inode_get_path( inode->parent, sz + len + 1 );
 657     if (!path)
 658         return NULL;
 659
 660     strcat( path, inode->name );
 661     strcat( path, "/" );
 662
 663     return path;
 664 }
 665
 666 static int inode_check_dir( struct inode *parent, const char *name )
 667 {
 668     char *path;
 669     unsigned int filter;
 670     struct inode *inode;
 671     struct stat st;
 672     int wd = -1, r = -1;
 673
 674     path = inode_get_path( parent, strlen(name) );
 675     if (!path)
 676         return r;
 677
 678     strcat( path, name );
 679
 680     r = stat( path, &st );
 681     if (r < 0) goto end;
 682
 683     if (!S_ISDIR(st.st_mode))
 684     {
 685         r = 0;
 686         goto end;
 687     }
 688
 689     r = 1;
 690
 691     filter = filter_from_inode( parent, 1 );
 692     if (!filter)
 693         goto end;
 694
 695     inode = inode_add( parent, st.st_dev, st.st_ino, name );
 696     if (!inode || inode->wd != -1)
 697         goto end;
 698
 699     wd = inotify_add_dir( path, filter );
 700     if (wd != -1)
 701         inode_set_wd( inode, wd );
 702     else
 703         free_inode( inode );
 704
 705 end:
 706     free( path );
 707     return r;
 708 }
 709
 710 static int prepend( char **path, const char *segment )
 711 {
 712     int extra;
 713     char *p;
 714
 715     extra = strlen( segment ) + 1;
 716     if (*path)
 717     {
 718         int len = strlen( *path ) + 1;
 719         p = realloc( *path, len + extra );
 720         if (!p) return 0;
 721         memmove( &p[ extra ], p, len );
 722         p[ extra - 1 ] = '/';
 723         memcpy( p, segment, extra - 1 );
 724     }
 725     else
 726     {
 727         p = malloc( extra );
 728         if (!p) return 0;
 729         memcpy( p, segment, extra );
 730     }
 731
 732     *path = p;
 733
 734     return 1;
 735 }
 736
 737 static void inotify_notify_all( struct inotify_event *ie )
 738 {
 739     unsigned int filter, action;
 740     struct inode *inode, *i;
 741     char *path = NULL;
 742     struct dir *dir;
 743
 744     inode = inode_from_wd( ie->wd );
 745     if (!inode)
 746     {
 747         fprintf( stderr, "no inode matches %d\n", ie->wd);
 748         return;
 749     }
 750
 751     filter = filter_from_event( ie );
 752
 753     if (ie->mask & IN_CREATE)
 754     {
 755         switch (inode_check_dir( inode, ie->name ))
 756         {
 757         case 1:
 758             filter &= ~FILE_NOTIFY_CHANGE_FILE_NAME;
 759             break;
 760         case 0:
 761             filter &= ~FILE_NOTIFY_CHANGE_DIR_NAME;
 762             break;
 763         default:
 764             break;
 765             /* Maybe the file disappeared before we could check it? */
 766         }
 767         action = FILE_ACTION_ADDED;
 768     }
 769     else if (ie->mask & IN_DELETE)
 770         action = FILE_ACTION_REMOVED;
 771     else
 772         action = FILE_ACTION_MODIFIED;
 773
 774     /*
 775      * Work our way up the inode hierarchy
 776      *  extending the relative path as we go
 777      *  and notifying all recursive watches.
 778      */
 779     if (!prepend( &path, ie->name ))
 780         return;
 781
 782     for (i = inode; i; i = i->parent)
 783     {
 784         LIST_FOR_EACH_ENTRY( dir, &i->dirs, struct dir, in_entry )
 785             if ((filter & dir->filter) && (i==inode || dir->subtree))
 786                 inotify_do_change_notify( dir, action, path );
 787
 788         if (!i->name || !prepend( &path, i->name ))
 789             break;
 790     }
 791
 792     free( path );
 793
 794     if (ie->mask & IN_DELETE)
 795     {
 796         i = inode_from_name( inode, ie->name );
 797         if (i)
 798             free_inode( i );
 799     }
 800 }
 801
 802 static void inotify_poll_event( struct fd *fd, int event )
 803 {
 804     int r, ofs, unix_fd;
 805     char buffer[0x1000];
 806     struct inotify_event *ie;
 807
 808     unix_fd = get_unix_fd( fd );
 809     r = read( unix_fd, buffer, sizeof buffer );
 810     if (r < 0)
 811     {
 812         fprintf(stderr,"inotify_poll_event(): inotify read failed!\n");
 813         return;
 814     }
 815
 816     for( ofs = 0; ofs < r - offsetof(struct inotify_event, name); )
 817     {
 818         ie = (struct inotify_event*) &buffer[ofs];
 819         if (!ie->len)
 820             break;
 821         ofs += offsetof( struct inotify_event, name[ie->len] );
 822         if (ofs > r) break;
 823         inotify_notify_all( ie );
 824     }
 825 }
 826
 827 static int inotify_get_info( struct fd *fd )
 828 {
 829     return 0;
 830 }
 831
 832 static inline struct fd *create_inotify_fd( void )
 833 {
 834     int unix_fd;
 835
 836     unix_fd = inotify_init();
 837     if (unix_fd<0)
 838         return NULL;
 839     return create_anonymous_fd( &inotify_fd_ops, unix_fd, NULL );
 840 }
 841
 842 static int map_flags( unsigned int filter )
 843 {
 844     unsigned int mask;
 845
 846     /* always watch these so we can track subdirectories in recursive watches */
 847     mask = (IN_MOVED_FROM | IN_MOVED_TO | IN_DELETE | IN_CREATE | IN_DELETE_SELF);
 848
 849     if (filter & FILE_NOTIFY_CHANGE_ATTRIBUTES)
 850         mask |= IN_ATTRIB;
 851     if (filter & FILE_NOTIFY_CHANGE_SIZE)
 852         mask |= IN_MODIFY;
 853     if (filter & FILE_NOTIFY_CHANGE_LAST_WRITE)
 854         mask |= IN_MODIFY;
 855     if (filter & FILE_NOTIFY_CHANGE_LAST_ACCESS)
 856         mask |= IN_ACCESS;
 857     if (filter & FILE_NOTIFY_CHANGE_SECURITY)
 858         mask |= IN_ATTRIB;
 859
 860     return mask;
 861 }
 862
 863 static int inotify_add_dir( char *path, unsigned int filter )
 864 {
 865     int wd = inotify_add_watch( get_unix_fd( inotify_fd ),
 866                                 path, map_flags( filter ) );
 867     if (wd != -1)
 868         set_fd_events( inotify_fd, POLLIN );
 869     return wd;
 870 }
 871
 872 static int init_inotify( void )
 873 {
 874     int i;
 875
 876     if (inotify_fd)
 877         return 1;
 878
 879     inotify_fd = create_inotify_fd();
 880     if (!inotify_fd)
 881         return 0;
 882
 883     for (i=0; i<HASH_SIZE; i++)
 884     {
 885         list_init( &inode_hash[i] );
 886         list_init( &wd_hash[i] );
 887     }
 888
 889     return 1;
 890 }
 891
 892 static int inotify_adjust_changes( struct dir *dir )
 893 {
 894     unsigned int filter;
 895     struct inode *inode;
 896     struct stat st;
 897     char path[32];
 898     int wd, unix_fd;
 899
 900     if (!inotify_fd)
 901         return 0;
 902
 903     unix_fd = get_unix_fd( dir->fd );
 904
 905     inode = dir->inode;
 906     if (!inode)
 907     {
 908         /* check if this fd is already being watched */
 909         if (-1 == fstat( unix_fd, &st ))
 910             return 0;
 911
 912         inode = get_inode( st.st_dev, st.st_ino );
 913         if (!inode)
 914             inode = create_inode( st.st_dev, st.st_ino );
 915         if (!inode)
 916             return 0;
 917         list_add_tail( &inode->dirs, &dir->in_entry );
 918         dir->inode = inode;
 919     }
 920
 921     filter = filter_from_inode( inode, 0 );
 922
 923     sprintf( path, "/proc/self/fd/%u", unix_fd );
 924     wd = inotify_add_dir( path, filter );
 925     if (wd == -1) return 0;
 926
 927     inode_set_wd( inode, wd );
 928
 929     return 1;
 930 }
 931
 932 static char *get_basename( const char *link )
 933 {
 934     char *buffer, *name = NULL;
 935     int r, n = 0x100;
 936
 937     while (1)
 938     {
 939         buffer = malloc( n );
 940         if (!buffer) return NULL;
 941
 942         r = readlink( link, buffer, n );
 943         if (r < 0)
 944             break;
 945
 946         if (r < n)
 947         {
 948             name = buffer;
 949             break;
 950         }
 951         free( buffer );
 952         n *= 2;
 953     }
 954
 955     if (name)
 956     {
 957         while (r > 0 && name[ r - 1 ] == '/' )
 958             r--;
 959         name[ r ] = 0;
 960
 961         name = strrchr( name, '/' );
 962         if (name)
 963             name = strdup( &name[1] );
 964     }
 965
 966     free( buffer );
 967     return name;
 968 }
 969
 970 static int dir_add_to_existing_notify( struct dir *dir )
 971 {
 972     struct inode *inode, *parent;
 973     unsigned int filter = 0;
 974     struct stat st, st_new;
 975     char link[35], *name;
 976     int wd, unix_fd;
 977
 978     if (!inotify_fd)
 979         return 0;
 980
 981     unix_fd = get_unix_fd( dir->fd );
 982
 983     /* check if it's in the list of inodes we want to watch */
 984     if (-1 == fstat( unix_fd, &st_new ))
 985         return 0;
 986     inode = find_inode( st_new.st_dev, st_new.st_ino );
 987     if (inode)
 988         return 0;
 989
 990     /* lookup the parent */
 991     sprintf( link, "/proc/self/fd/%u/..", unix_fd );
 992     if (-1 == stat( link, &st ))
 993         return 0;
 994
 995     /*
 996      * If there's no parent, stop.  We could keep going adding
 997      *  ../ to the path until we hit the root of the tree or
 998      *  find a recursively watched ancestor.
 999      * Assume it's too expensive to search up the tree for now.
1000      */
1001     parent = find_inode( st.st_dev, st.st_ino );
1002     if (!parent)
1003         return 0;
1004
1005     if (parent->wd == -1)
1006         return 0;
1007
1008     filter = filter_from_inode( parent, 1 );
1009     if (!filter)
1010         return 0;
1011
1012     sprintf( link, "/proc/self/fd/%u", unix_fd );
1013     name = get_basename( link );
1014     if (!name)
1015         return 0;
1016     inode = inode_add( parent, st_new.st_dev, st_new.st_ino, name );
1017     free( name );
1018     if (!inode)
1019         return 0;
1020
1021     /* Couldn't find this inode at the start of the function, must be new */
1022     assert( inode->wd == -1 );
1023
1024     wd = inotify_add_dir( link, filter );
1025     if (wd != -1)
1026         inode_set_wd( inode, wd );
1027
1028     return 1;
1029 }
1030
1031 #else
1032
1033 static int init_inotify( void )
1034 {
1035     return 0;
1036 }
1037
1038 static int inotify_adjust_changes( struct dir *dir )
1039 {
1040     return 0;
1041 }
1042
1043 static void free_inode( struct inode *inode )
1044 {
1045     assert( 0 );
1046 }
1047
1048 static int dir_add_to_existing_notify( struct dir *dir )
1049 {
1050     return 0;
1051 }
1052
1053 #endif  /* USE_INOTIFY */
1054
1055 struct object *create_dir_obj( struct fd *fd )
1056 {
1057     struct dir *dir;
1058
1059     dir = alloc_object( &dir_ops );
1060     if (!dir)
1061         return NULL;
1062
1063     list_init( &dir->change_q );
1064     list_init( &dir->change_records );
1065     dir->event = NULL;
1066     dir->filter = 0;
1067     dir->notified = 0;
1068     dir->signaled = 0;
1069     dir->want_data = 0;
1070     dir->inode = NULL;
1071     grab_object( fd );
1072     dir->fd = fd;
1073     set_fd_user( fd, &dir_fd_ops, &dir->obj );
1074
1075     dir_add_to_existing_notify( dir );
1076
1077     return &dir->obj;
1078 }
1079
1080 /* enable change notifications for a directory */
1081 DECL_HANDLER(read_directory_changes)
1082 {
1083     struct event *event = NULL;
1084     struct dir *dir;
1085
1086     if (!req->filter)
1087     {
1088         set_error(STATUS_INVALID_PARAMETER);
1089         return;
1090     }
1091
1092     dir = get_dir_obj( current->process, req->handle, 0 );
1093     if (!dir)
1094         return;
1095
1096     /* possibly send changes through an event flag */
1097     if (req->event)
1098     {
1099         event = get_event_obj( current->process, req->event, EVENT_MODIFY_STATE );
1100         if (!event)
1101             goto end;
1102     }
1103
1104     /* discard the current data, and move onto the next event */
1105     if (dir->event) release_object( dir->event );
1106     dir->event = event;
1107
1108     /* requests don't timeout */
1109     if ( req->io_apc && !create_async( current, NULL, &dir->change_q,
1110                         req->io_apc, req->io_user, req->io_sb ))
1111         return;
1112
1113     /* assign it once */
1114     if (!dir->filter)
1115     {
1116         init_inotify();
1117         insert_change( dir );
1118         dir->filter = req->filter;
1119         dir->subtree = req->subtree;
1120         dir->want_data = req->want_data;
1121     }
1122
1123     /* remove any notifications */
1124     if (dir->signaled>0)
1125         dir->signaled--;
1126
1127     /* clear the event */
1128     if (event)
1129         reset_event( event );
1130
1131     /* if there's already a change in the queue, send it */
1132     if (!list_empty( &dir->change_q ) &&
1133         !list_empty( &dir->change_records ))
1134         async_terminate_head( &dir->change_q, STATUS_ALERTED );
1135
1136     /* setup the real notification */
1137     if (!inotify_adjust_changes( dir ))
1138         dnotify_adjust_changes( dir );
1139
1140     set_error(STATUS_PENDING);
1141
1142 end:
1143     release_object( dir );
1144 }
1145
1146 DECL_HANDLER(read_change)
1147 {
1148     struct change_record *record;
1149     struct dir *dir;
1150
1151     dir = get_dir_obj( current->process, req->handle, 0 );
1152     if (!dir)
1153         return;
1154
1155     if ((record = get_first_change_record( dir )) != NULL)
1156     {
1157         reply->action = record->action;
1158         set_reply_data( record->name, record->len );
1159         free( record );
1160     }
1161     else
1162         set_error( STATUS_NO_DATA_DETECTED );
1163
1164     /* now signal it */
1165     dir->signaled++;
1166     dir_signal_changed( dir );
1167
1168     release_object( dir );
1169 }