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., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, 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     unsigned int   filter;   /* notification filter */
 151     int            notified; /* SIGIO counter */
 152     int            want_data; /* return change data */
 153     int            subtree;  /* do we want to watch subdirectories? */
 154     struct list    change_records;   /* data for the change */
 155     struct list    in_entry; /* entry in the inode dirs list */
 156     struct inode  *inode;    /* inode of the associated directory */
 157 };
 158
 159 static struct fd *dir_get_fd( struct object *obj );
 160 static void dir_dump( struct object *obj, int verbose );
 161 static void dir_destroy( struct object *obj );
 162
 163 static const struct object_ops dir_ops =
 164 {
 165     sizeof(struct dir),       /* size */
 166     dir_dump,                 /* dump */
 167     add_queue,                /* add_queue */
 168     remove_queue,             /* remove_queue */
 169     default_fd_signaled,      /* signaled */
 170     no_satisfied,             /* satisfied */
 171     no_signal,                /* signal */
 172     dir_get_fd,               /* get_fd */
 173     default_fd_map_access,    /* map_access */
 174     no_lookup_name,           /* lookup_name */
 175     no_open_file,             /* open_file */
 176     fd_close_handle,          /* close_handle */
 177     dir_destroy               /* destroy */
 178 };
 179
 180 static int dir_get_poll_events( struct fd *fd );
 181 static enum server_fd_type dir_get_fd_type( struct fd *fd );
 182
 183 static const struct fd_ops dir_fd_ops =
 184 {
 185     dir_get_poll_events,         /* get_poll_events */
 186     default_poll_event,          /* poll_event */
 187     no_flush,                    /* flush */
 188     dir_get_fd_type,             /* get_fd_type */
 189     default_fd_ioctl,            /* ioctl */
 190     default_fd_queue_async,      /* queue_async */
 191     default_fd_reselect_async,   /* reselect_async */
 192     default_fd_cancel_async      /* cancel_async */
 193 };
 194
 195 static struct list change_list = LIST_INIT(change_list);
 196
 197 static void dnotify_adjust_changes( struct dir *dir )
 198 {
 199 #if defined(F_SETSIG) && defined(F_NOTIFY)
 200     int fd = get_unix_fd( dir->fd );
 201     unsigned int filter = dir->filter;
 202     unsigned int val;
 203     if ( 0 > fcntl( fd, F_SETSIG, SIGIO) )
 204         return;
 205
 206     val = DN_MULTISHOT;
 207     if (filter & FILE_NOTIFY_CHANGE_FILE_NAME)
 208         val |= DN_RENAME | DN_DELETE | DN_CREATE;
 209     if (filter & FILE_NOTIFY_CHANGE_DIR_NAME)
 210         val |= DN_RENAME | DN_DELETE | DN_CREATE;
 211     if (filter & FILE_NOTIFY_CHANGE_ATTRIBUTES)
 212         val |= DN_ATTRIB;
 213     if (filter & FILE_NOTIFY_CHANGE_SIZE)
 214         val |= DN_MODIFY;
 215     if (filter & FILE_NOTIFY_CHANGE_LAST_WRITE)
 216         val |= DN_MODIFY;
 217     if (filter & FILE_NOTIFY_CHANGE_LAST_ACCESS)
 218         val |= DN_ACCESS;
 219     if (filter & FILE_NOTIFY_CHANGE_CREATION)
 220         val |= DN_CREATE;
 221     if (filter & FILE_NOTIFY_CHANGE_SECURITY)
 222         val |= DN_ATTRIB;
 223     fcntl( fd, F_NOTIFY, val );
 224 #endif
 225 }
 226
 227 /* insert change in the global list */
 228 static inline void insert_change( struct dir *dir )
 229 {
 230     sigset_t sigset;
 231
 232     sigemptyset( &sigset );
 233     sigaddset( &sigset, SIGIO );
 234     sigprocmask( SIG_BLOCK, &sigset, NULL );
 235     list_add_head( &change_list, &dir->entry );
 236     sigprocmask( SIG_UNBLOCK, &sigset, NULL );
 237 }
 238
 239 /* remove change from the global list */
 240 static inline void remove_change( struct dir *dir )
 241 {
 242     sigset_t sigset;
 243
 244     sigemptyset( &sigset );
 245     sigaddset( &sigset, SIGIO );
 246     sigprocmask( SIG_BLOCK, &sigset, NULL );
 247     list_remove( &dir->entry );
 248     sigprocmask( SIG_UNBLOCK, &sigset, NULL );
 249 }
 250
 251 static void dir_dump( struct object *obj, int verbose )
 252 {
 253     struct dir *dir = (struct dir *)obj;
 254     assert( obj->ops == &dir_ops );
 255     fprintf( stderr, "Dirfile fd=%p filter=%08x\n", dir->fd, dir->filter );
 256 }
 257
 258 /* enter here directly from SIGIO signal handler */
 259 void do_change_notify( int unix_fd )
 260 {
 261     struct dir *dir;
 262
 263     /* FIXME: this is O(n) ... probably can be improved */
 264     LIST_FOR_EACH_ENTRY( dir, &change_list, struct dir, entry )
 265     {
 266         if (get_unix_fd( dir->fd ) != unix_fd) continue;
 267         interlocked_xchg_add( &dir->notified, 1 );
 268         break;
 269     }
 270 }
 271
 272 /* SIGIO callback, called synchronously with the poll loop */
 273 void sigio_callback(void)
 274 {
 275     struct dir *dir;
 276
 277     LIST_FOR_EACH_ENTRY( dir, &change_list, struct dir, entry )
 278     {
 279         if (interlocked_xchg( &dir->notified, 0 ))
 280             fd_async_wake_up( dir->fd, ASYNC_TYPE_WAIT, STATUS_NOTIFY_ENUM_DIR );
 281     }
 282 }
 283
 284 static struct fd *dir_get_fd( struct object *obj )
 285 {
 286     struct dir *dir = (struct dir *)obj;
 287     assert( obj->ops == &dir_ops );
 288     return (struct fd *)grab_object( dir->fd );
 289 }
 290
 291 static struct change_record *get_first_change_record( struct dir *dir )
 292 {
 293     struct list *ptr = list_head( &dir->change_records );
 294     if (!ptr) return NULL;
 295     list_remove( ptr );
 296     return LIST_ENTRY( ptr, struct change_record, entry );
 297 }
 298
 299 static void dir_destroy( struct object *obj )
 300 {
 301     struct change_record *record;
 302     struct dir *dir = (struct dir *)obj;
 303     assert (obj->ops == &dir_ops);
 304
 305     if (dir->filter)
 306         remove_change( dir );
 307
 308     if (dir->inode)
 309     {
 310         list_remove( &dir->in_entry );
 311         free_inode( dir->inode );
 312     }
 313
 314     while ((record = get_first_change_record( dir ))) free( record );
 315
 316     release_object( dir->fd );
 317
 318     if (inotify_fd && list_empty( &change_list ))
 319     {
 320         release_object( inotify_fd );
 321         inotify_fd = NULL;
 322     }
 323 }
 324
 325 static struct dir *
 326 get_dir_obj( struct process *process, obj_handle_t handle, unsigned int access )
 327 {
 328     return (struct dir *)get_handle_obj( process, handle, access, &dir_ops );
 329 }
 330
 331 static int dir_get_poll_events( struct fd *fd )
 332 {
 333     return 0;
 334 }
 335
 336 static enum server_fd_type dir_get_fd_type( struct fd *fd )
 337 {
 338     return FD_TYPE_DIR;
 339 }
 340
 341 #ifdef USE_INOTIFY
 342
 343 #define HASH_SIZE 31
 344
 345 struct inode {
 346     struct list ch_entry;    /* entry in the children list */
 347     struct list children;    /* children of this inode */
 348     struct inode *parent;    /* parent of this inode */
 349     struct list dirs;        /* directory handles watching this inode */
 350     struct list ino_entry;   /* entry in the inode hash */
 351     struct list wd_entry;    /* entry in the watch descriptor hash */
 352     dev_t dev;               /* device number */
 353     ino_t ino;               /* device's inode number */
 354     int wd;                  /* inotify's watch descriptor */
 355     char *name;              /* basename name of the inode */
 356 };
 357
 358 struct list inode_hash[ HASH_SIZE ];
 359 struct list wd_hash[ HASH_SIZE ];
 360
 361 static int inotify_add_dir( char *path, unsigned int filter );
 362
 363 static struct inode *inode_from_wd( int wd )
 364 {
 365     struct list *bucket = &wd_hash[ wd % HASH_SIZE ];
 366     struct inode *inode;
 367
 368     LIST_FOR_EACH_ENTRY( inode, bucket, struct inode, wd_entry )
 369         if (inode->wd == wd)
 370             return inode;
 371
 372     return NULL;
 373 }
 374
 375 static inline struct list *get_hash_list( dev_t dev, ino_t ino )
 376 {
 377     return &inode_hash[ (ino ^ dev) % HASH_SIZE ];
 378 }
 379
 380 static struct inode *find_inode( dev_t dev, ino_t ino )
 381 {
 382     struct list *bucket = get_hash_list( dev, ino );
 383     struct inode *inode;
 384
 385     LIST_FOR_EACH_ENTRY( inode, bucket, struct inode, ino_entry )
 386         if (inode->ino == ino && inode->dev == dev)
 387              return inode;
 388
 389     return NULL;
 390 }
 391
 392 static struct inode *create_inode( dev_t dev, ino_t ino )
 393 {
 394     struct inode *inode;
 395
 396     inode = malloc( sizeof *inode );
 397     if (inode)
 398     {
 399         list_init( &inode->children );
 400         list_init( &inode->dirs );
 401         inode->ino = ino;
 402         inode->dev = dev;
 403         inode->wd = -1;
 404         inode->parent = NULL;
 405         inode->name = NULL;
 406         list_add_tail( get_hash_list( dev, ino ), &inode->ino_entry );
 407     }
 408     return inode;
 409 }
 410
 411 static struct inode *get_inode( dev_t dev, ino_t ino )
 412 {
 413     struct inode *inode;
 414
 415     inode = find_inode( dev, ino );
 416     if (inode)
 417         return inode;
 418     return create_inode( dev, ino );
 419 }
 420
 421 static void inode_set_wd( struct inode *inode, int wd )
 422 {
 423     if (inode->wd != -1)
 424         list_remove( &inode->wd_entry );
 425     inode->wd = wd;
 426     list_add_tail( &wd_hash[ wd % HASH_SIZE ], &inode->wd_entry );
 427 }
 428
 429 static void inode_set_name( struct inode *inode, const char *name )
 430 {
 431     free (inode->name);
 432     inode->name = name ? strdup( name ) : NULL;
 433 }
 434
 435 static void free_inode( struct inode *inode )
 436 {
 437     int subtree = 0, watches = 0;
 438     struct dir *dir;
 439
 440     LIST_FOR_EACH_ENTRY( dir, &inode->dirs, struct dir, in_entry )
 441     {
 442         subtree |= dir->subtree;
 443         watches++;
 444     }
 445
 446     if (!subtree && !inode->parent)
 447     {
 448         struct inode *tmp, *next;
 449         LIST_FOR_EACH_ENTRY_SAFE( tmp, next, &inode->children,
 450                                   struct inode, ch_entry )
 451         {
 452             assert( tmp != inode );
 453             assert( tmp->parent == inode );
 454             free_inode( tmp );
 455         }
 456     }
 457
 458     if (watches)
 459         return;
 460
 461     if (inode->parent)
 462         list_remove( &inode->ch_entry );
 463
 464     if (inode->wd != -1)
 465     {
 466         inotify_remove_watch( get_unix_fd( inotify_fd ), inode->wd );
 467         list_remove( &inode->wd_entry );
 468     }
 469     list_remove( &inode->ino_entry );
 470
 471     free( inode->name );
 472     free( inode );
 473 }
 474
 475 static struct inode *inode_add( struct inode *parent,
 476                                 dev_t dev, ino_t ino, const char *name )
 477 {
 478     struct inode *inode;
 479
 480     inode = get_inode( dev, ino );
 481     if (!inode)
 482         return NULL;
 483
 484     if (!inode->parent)
 485     {
 486         list_add_tail( &parent->children, &inode->ch_entry );
 487         inode->parent = parent;
 488         assert( inode != parent );
 489     }
 490     inode_set_name( inode, name );
 491
 492     return inode;
 493 }
 494
 495 static struct inode *inode_from_name( struct inode *inode, const char *name )
 496 {
 497     struct inode *i;
 498
 499     LIST_FOR_EACH_ENTRY( i, &inode->children, struct inode, ch_entry )
 500         if (i->name && !strcmp( i->name, name ))
 501             return i;
 502     return NULL;
 503 }
 504
 505 static int inotify_get_poll_events( struct fd *fd );
 506 static void inotify_poll_event( struct fd *fd, int event );
 507
 508 static const struct fd_ops inotify_fd_ops =
 509 {
 510     inotify_get_poll_events,     /* get_poll_events */
 511     inotify_poll_event,          /* poll_event */
 512     NULL,                        /* flush */
 513     NULL,                        /* get_fd_type */
 514     NULL,                        /* ioctl */
 515     NULL,                        /* queue_async */
 516     NULL,                        /* reselect_async */
 517     NULL,                        /* cancel_async */
 518 };
 519
 520 static int inotify_get_poll_events( struct fd *fd )
 521 {
 522     return POLLIN;
 523 }
 524
 525 static void inotify_do_change_notify( struct dir *dir, unsigned int action,
 526                                       const char *relpath )
 527 {
 528     struct change_record *record;
 529
 530     assert( dir->obj.ops == &dir_ops );
 531
 532     if (dir->want_data)
 533     {
 534         size_t len = strlen(relpath);
 535         record = malloc( offsetof(struct change_record, name[len]) );
 536         if (!record)
 537             return;
 538
 539         record->action = action;
 540         memcpy( record->name, relpath, len );
 541         record->len = len;
 542
 543         list_add_tail( &dir->change_records, &record->entry );
 544     }
 545
 546     fd_async_wake_up( dir->fd, ASYNC_TYPE_WAIT, STATUS_ALERTED );
 547 }
 548
 549 static unsigned int filter_from_event( struct inotify_event *ie )
 550 {
 551     unsigned int filter = 0;
 552
 553     if (ie->mask & (IN_MOVED_FROM | IN_MOVED_TO | IN_DELETE | IN_CREATE))
 554         filter |= FILE_NOTIFY_CHANGE_FILE_NAME | FILE_NOTIFY_CHANGE_DIR_NAME;
 555     if (ie->mask & IN_MODIFY)
 556         filter |= FILE_NOTIFY_CHANGE_SIZE | FILE_NOTIFY_CHANGE_LAST_WRITE;
 557     if (ie->mask & IN_ATTRIB)
 558         filter |= FILE_NOTIFY_CHANGE_ATTRIBUTES | FILE_NOTIFY_CHANGE_SECURITY;
 559     if (ie->mask & IN_ACCESS)
 560         filter |= FILE_NOTIFY_CHANGE_LAST_ACCESS;
 561     if (ie->mask & IN_CREATE)
 562         filter |= FILE_NOTIFY_CHANGE_CREATION;
 563
 564     return filter;
 565 }
 566
 567 /* scan up the parent directories for watches */
 568 static unsigned int filter_from_inode( struct inode *inode, int is_parent )
 569 {
 570     unsigned int filter = 0;
 571     struct dir *dir;
 572
 573     /* combine filters from parents watching subtrees */
 574     while (inode)
 575     {
 576         LIST_FOR_EACH_ENTRY( dir, &inode->dirs, struct dir, in_entry )
 577             if (dir->subtree || !is_parent)
 578                 filter |= dir->filter;
 579         is_parent = 1;
 580         inode = inode->parent;
 581     }
 582
 583     return filter;
 584 }
 585
 586 static char *inode_get_path( struct inode *inode, int sz )
 587 {
 588     struct list *head;
 589     char *path;
 590     int len;
 591
 592     if (!inode)
 593         return NULL;
 594
 595     head = list_head( &inode->dirs );
 596     if (head)
 597     {
 598         int unix_fd = get_unix_fd( LIST_ENTRY( head, struct dir, in_entry )->fd );
 599         path = malloc ( 32 + sz );
 600         if (path)
 601             sprintf( path, "/proc/self/fd/%u/", unix_fd );
 602         return path;
 603     }
 604
 605     if (!inode->name)
 606         return NULL;
 607
 608     len = strlen( inode->name );
 609     path = inode_get_path( inode->parent, sz + len + 1 );
 610     if (!path)
 611         return NULL;
 612
 613     strcat( path, inode->name );
 614     strcat( path, "/" );
 615
 616     return path;
 617 }
 618
 619 static int inode_check_dir( struct inode *parent, const char *name )
 620 {
 621     char *path;
 622     unsigned int filter;
 623     struct inode *inode;
 624     struct stat st;
 625     int wd = -1, r = -1;
 626
 627     path = inode_get_path( parent, strlen(name) );
 628     if (!path)
 629         return r;
 630
 631     strcat( path, name );
 632
 633     r = stat( path, &st );
 634     if (r < 0) goto end;
 635
 636     if (!S_ISDIR(st.st_mode))
 637     {
 638         r = 0;
 639         goto end;
 640     }
 641
 642     r = 1;
 643
 644     filter = filter_from_inode( parent, 1 );
 645     if (!filter)
 646         goto end;
 647
 648     inode = inode_add( parent, st.st_dev, st.st_ino, name );
 649     if (!inode || inode->wd != -1)
 650         goto end;
 651
 652     wd = inotify_add_dir( path, filter );
 653     if (wd != -1)
 654         inode_set_wd( inode, wd );
 655     else
 656         free_inode( inode );
 657
 658 end:
 659     free( path );
 660     return r;
 661 }
 662
 663 static int prepend( char **path, const char *segment )
 664 {
 665     int extra;
 666     char *p;
 667
 668     extra = strlen( segment ) + 1;
 669     if (*path)
 670     {
 671         int len = strlen( *path ) + 1;
 672         p = realloc( *path, len + extra );
 673         if (!p) return 0;
 674         memmove( &p[ extra ], p, len );
 675         p[ extra - 1 ] = '/';
 676         memcpy( p, segment, extra - 1 );
 677     }
 678     else
 679     {
 680         p = malloc( extra );
 681         if (!p) return 0;
 682         memcpy( p, segment, extra );
 683     }
 684
 685     *path = p;
 686
 687     return 1;
 688 }
 689
 690 static void inotify_notify_all( struct inotify_event *ie )
 691 {
 692     unsigned int filter, action;
 693     struct inode *inode, *i;
 694     char *path = NULL;
 695     struct dir *dir;
 696
 697     inode = inode_from_wd( ie->wd );
 698     if (!inode)
 699     {
 700         fprintf( stderr, "no inode matches %d\n", ie->wd);
 701         return;
 702     }
 703
 704     filter = filter_from_event( ie );
 705
 706     if (ie->mask & IN_CREATE)
 707     {
 708         switch (inode_check_dir( inode, ie->name ))
 709         {
 710         case 1:
 711             filter &= ~FILE_NOTIFY_CHANGE_FILE_NAME;
 712             break;
 713         case 0:
 714             filter &= ~FILE_NOTIFY_CHANGE_DIR_NAME;
 715             break;
 716         default:
 717             break;
 718             /* Maybe the file disappeared before we could check it? */
 719         }
 720         action = FILE_ACTION_ADDED;
 721     }
 722     else if (ie->mask & IN_DELETE)
 723         action = FILE_ACTION_REMOVED;
 724     else
 725         action = FILE_ACTION_MODIFIED;
 726
 727     /*
 728      * Work our way up the inode hierarchy
 729      *  extending the relative path as we go
 730      *  and notifying all recursive watches.
 731      */
 732     if (!prepend( &path, ie->name ))
 733         return;
 734
 735     for (i = inode; i; i = i->parent)
 736     {
 737         LIST_FOR_EACH_ENTRY( dir, &i->dirs, struct dir, in_entry )
 738             if ((filter & dir->filter) && (i==inode || dir->subtree))
 739                 inotify_do_change_notify( dir, action, path );
 740
 741         if (!i->name || !prepend( &path, i->name ))
 742             break;
 743     }
 744
 745     free( path );
 746
 747     if (ie->mask & IN_DELETE)
 748     {
 749         i = inode_from_name( inode, ie->name );
 750         if (i)
 751             free_inode( i );
 752     }
 753 }
 754
 755 static void inotify_poll_event( struct fd *fd, int event )
 756 {
 757     int r, ofs, unix_fd;
 758     char buffer[0x1000];
 759     struct inotify_event *ie;
 760
 761     unix_fd = get_unix_fd( fd );
 762     r = read( unix_fd, buffer, sizeof buffer );
 763     if (r < 0)
 764     {
 765         fprintf(stderr,"inotify_poll_event(): inotify read failed!\n");
 766         return;
 767     }
 768
 769     for( ofs = 0; ofs < r - offsetof(struct inotify_event, name); )
 770     {
 771         ie = (struct inotify_event*) &buffer[ofs];
 772         if (!ie->len)
 773             break;
 774         ofs += offsetof( struct inotify_event, name[ie->len] );
 775         if (ofs > r) break;
 776         inotify_notify_all( ie );
 777     }
 778 }
 779
 780 static inline struct fd *create_inotify_fd( void )
 781 {
 782     int unix_fd;
 783
 784     unix_fd = inotify_init();
 785     if (unix_fd<0)
 786         return NULL;
 787     return create_anonymous_fd( &inotify_fd_ops, unix_fd, NULL, 0 );
 788 }
 789
 790 static int map_flags( unsigned int filter )
 791 {
 792     unsigned int mask;
 793
 794     /* always watch these so we can track subdirectories in recursive watches */
 795     mask = (IN_MOVED_FROM | IN_MOVED_TO | IN_DELETE | IN_CREATE | IN_DELETE_SELF);
 796
 797     if (filter & FILE_NOTIFY_CHANGE_ATTRIBUTES)
 798         mask |= IN_ATTRIB;
 799     if (filter & FILE_NOTIFY_CHANGE_SIZE)
 800         mask |= IN_MODIFY;
 801     if (filter & FILE_NOTIFY_CHANGE_LAST_WRITE)
 802         mask |= IN_MODIFY;
 803     if (filter & FILE_NOTIFY_CHANGE_LAST_ACCESS)
 804         mask |= IN_ACCESS;
 805     if (filter & FILE_NOTIFY_CHANGE_SECURITY)
 806         mask |= IN_ATTRIB;
 807
 808     return mask;
 809 }
 810
 811 static int inotify_add_dir( char *path, unsigned int filter )
 812 {
 813     int wd = inotify_add_watch( get_unix_fd( inotify_fd ),
 814                                 path, map_flags( filter ) );
 815     if (wd != -1)
 816         set_fd_events( inotify_fd, POLLIN );
 817     return wd;
 818 }
 819
 820 static int init_inotify( void )
 821 {
 822     int i;
 823
 824     if (inotify_fd)
 825         return 1;
 826
 827     inotify_fd = create_inotify_fd();
 828     if (!inotify_fd)
 829         return 0;
 830
 831     for (i=0; i<HASH_SIZE; i++)
 832     {
 833         list_init( &inode_hash[i] );
 834         list_init( &wd_hash[i] );
 835     }
 836
 837     return 1;
 838 }
 839
 840 static int inotify_adjust_changes( struct dir *dir )
 841 {
 842     unsigned int filter;
 843     struct inode *inode;
 844     struct stat st;
 845     char path[32];
 846     int wd, unix_fd;
 847
 848     if (!inotify_fd)
 849         return 0;
 850
 851     unix_fd = get_unix_fd( dir->fd );
 852
 853     inode = dir->inode;
 854     if (!inode)
 855     {
 856         /* check if this fd is already being watched */
 857         if (-1 == fstat( unix_fd, &st ))
 858             return 0;
 859
 860         inode = get_inode( st.st_dev, st.st_ino );
 861         if (!inode)
 862             inode = create_inode( st.st_dev, st.st_ino );
 863         if (!inode)
 864             return 0;
 865         list_add_tail( &inode->dirs, &dir->in_entry );
 866         dir->inode = inode;
 867     }
 868
 869     filter = filter_from_inode( inode, 0 );
 870
 871     sprintf( path, "/proc/self/fd/%u", unix_fd );
 872     wd = inotify_add_dir( path, filter );
 873     if (wd == -1) return 0;
 874
 875     inode_set_wd( inode, wd );
 876
 877     return 1;
 878 }
 879
 880 static char *get_basename( const char *link )
 881 {
 882     char *buffer, *name = NULL;
 883     int r, n = 0x100;
 884
 885     while (1)
 886     {
 887         buffer = malloc( n );
 888         if (!buffer) return NULL;
 889
 890         r = readlink( link, buffer, n );
 891         if (r < 0)
 892             break;
 893
 894         if (r < n)
 895         {
 896             name = buffer;
 897             break;
 898         }
 899         free( buffer );
 900         n *= 2;
 901     }
 902
 903     if (name)
 904     {
 905         while (r > 0 && name[ r - 1 ] == '/' )
 906             r--;
 907         name[ r ] = 0;
 908
 909         name = strrchr( name, '/' );
 910         if (name)
 911             name = strdup( &name[1] );
 912     }
 913
 914     free( buffer );
 915     return name;
 916 }
 917
 918 static int dir_add_to_existing_notify( struct dir *dir )
 919 {
 920     struct inode *inode, *parent;
 921     unsigned int filter = 0;
 922     struct stat st, st_new;
 923     char link[35], *name;
 924     int wd, unix_fd;
 925
 926     if (!inotify_fd)
 927         return 0;
 928
 929     unix_fd = get_unix_fd( dir->fd );
 930
 931     /* check if it's in the list of inodes we want to watch */
 932     if (-1 == fstat( unix_fd, &st_new ))
 933         return 0;
 934     inode = find_inode( st_new.st_dev, st_new.st_ino );
 935     if (inode)
 936         return 0;
 937
 938     /* lookup the parent */
 939     sprintf( link, "/proc/self/fd/%u/..", unix_fd );
 940     if (-1 == stat( link, &st ))
 941         return 0;
 942
 943     /*
 944      * If there's no parent, stop.  We could keep going adding
 945      *  ../ to the path until we hit the root of the tree or
 946      *  find a recursively watched ancestor.
 947      * Assume it's too expensive to search up the tree for now.
 948      */
 949     parent = find_inode( st.st_dev, st.st_ino );
 950     if (!parent)
 951         return 0;
 952
 953     if (parent->wd == -1)
 954         return 0;
 955
 956     filter = filter_from_inode( parent, 1 );
 957     if (!filter)
 958         return 0;
 959
 960     sprintf( link, "/proc/self/fd/%u", unix_fd );
 961     name = get_basename( link );
 962     if (!name)
 963         return 0;
 964     inode = inode_add( parent, st_new.st_dev, st_new.st_ino, name );
 965     free( name );
 966     if (!inode)
 967         return 0;
 968
 969     /* Couldn't find this inode at the start of the function, must be new */
 970     assert( inode->wd == -1 );
 971
 972     wd = inotify_add_dir( link, filter );
 973     if (wd != -1)
 974         inode_set_wd( inode, wd );
 975
 976     return 1;
 977 }
 978
 979 #else
 980
 981 static int init_inotify( void )
 982 {
 983     return 0;
 984 }
 985
 986 static int inotify_adjust_changes( struct dir *dir )
 987 {
 988     return 0;
 989 }
 990
 991 static void free_inode( struct inode *inode )
 992 {
 993     assert( 0 );
 994 }
 995
 996 static int dir_add_to_existing_notify( struct dir *dir )
 997 {
 998     return 0;
 999 }
1000
1001 #endif  /* USE_INOTIFY */
1002
1003 struct object *create_dir_obj( struct fd *fd )
1004 {
1005     struct dir *dir;
1006
1007     dir = alloc_object( &dir_ops );
1008     if (!dir)
1009         return NULL;
1010
1011     list_init( &dir->change_records );
1012     dir->filter = 0;
1013     dir->notified = 0;
1014     dir->want_data = 0;
1015     dir->inode = NULL;
1016     grab_object( fd );
1017     dir->fd = fd;
1018     set_fd_user( fd, &dir_fd_ops, &dir->obj );
1019
1020     dir_add_to_existing_notify( dir );
1021
1022     return &dir->obj;
1023 }
1024
1025 /* enable change notifications for a directory */
1026 DECL_HANDLER(read_directory_changes)
1027 {
1028     struct dir *dir;
1029     struct async *async;
1030
1031     if (!req->filter)
1032     {
1033         set_error(STATUS_INVALID_PARAMETER);
1034         return;
1035     }
1036
1037     dir = get_dir_obj( current->process, req->handle, 0 );
1038     if (!dir)
1039         return;
1040
1041     /* requests don't timeout */
1042     if (!(async = fd_queue_async( dir->fd, &req->async, ASYNC_TYPE_WAIT, 0 ))) goto end;
1043
1044     /* assign it once */
1045     if (!dir->filter)
1046     {
1047         init_inotify();
1048         insert_change( dir );
1049         dir->filter = req->filter;
1050         dir->subtree = req->subtree;
1051         dir->want_data = req->want_data;
1052     }
1053
1054     /* if there's already a change in the queue, send it */
1055     if (!list_empty( &dir->change_records ))
1056         fd_async_wake_up( dir->fd, ASYNC_TYPE_WAIT, STATUS_ALERTED );
1057
1058     /* setup the real notification */
1059     if (!inotify_adjust_changes( dir ))
1060         dnotify_adjust_changes( dir );
1061
1062     release_object( async );
1063     set_error(STATUS_PENDING);
1064
1065 end:
1066     release_object( dir );
1067 }
1068
1069 DECL_HANDLER(read_change)
1070 {
1071     struct change_record *record;
1072     struct dir *dir;
1073
1074     dir = get_dir_obj( current->process, req->handle, 0 );
1075     if (!dir)
1076         return;
1077
1078     if ((record = get_first_change_record( dir )) != NULL)
1079     {
1080         reply->action = record->action;
1081         set_reply_data( record->name, record->len );
1082         free( record );
1083     }
1084     else
1085         set_error( STATUS_NO_DATA_DETECTED );
1086
1087     release_object( dir );
1088 }