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     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     fd_close_handle,          /* close_handle */
 181     dir_destroy               /* destroy */
 182 };
 183
 184 static int dir_get_poll_events( struct fd *fd );
 185 static enum server_fd_type dir_get_info( struct fd *fd, int *flags );
 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 enum server_fd_type dir_get_info( struct fd *fd, int *flags )
 376 {
 377     *flags = 0;
 378     return FD_TYPE_DIR;
 379 }
 380
 381 static void dir_cancel_async( struct fd *fd )
 382 {
 383     struct dir *dir = (struct dir *) get_fd_user( fd );
 384     async_terminate_queue( &dir->change_q, STATUS_CANCELLED );
 385 }
 386
 387
 388 #ifdef USE_INOTIFY
 389
 390 #define HASH_SIZE 31
 391
 392 struct inode {
 393     struct list ch_entry;    /* entry in the children list */
 394     struct list children;    /* children of this inode */
 395     struct inode *parent;    /* parent of this inode */
 396     struct list dirs;        /* directory handles watching this inode */
 397     struct list ino_entry;   /* entry in the inode hash */
 398     struct list wd_entry;    /* entry in the watch descriptor hash */
 399     dev_t dev;               /* device number */
 400     ino_t ino;               /* device's inode number */
 401     int wd;                  /* inotify's watch descriptor */
 402     char *name;              /* basename name of the inode */
 403 };
 404
 405 struct list inode_hash[ HASH_SIZE ];
 406 struct list wd_hash[ HASH_SIZE ];
 407
 408 static int inotify_add_dir( char *path, unsigned int filter );
 409
 410 static struct inode *inode_from_wd( int wd )
 411 {
 412     struct list *bucket = &wd_hash[ wd % HASH_SIZE ];
 413     struct inode *inode;
 414
 415     LIST_FOR_EACH_ENTRY( inode, bucket, struct inode, wd_entry )
 416         if (inode->wd == wd)
 417             return inode;
 418
 419     return NULL;
 420 }
 421
 422 static inline struct list *get_hash_list( dev_t dev, ino_t ino )
 423 {
 424     return &inode_hash[ (ino ^ dev) % HASH_SIZE ];
 425 }
 426
 427 static struct inode *find_inode( dev_t dev, ino_t ino )
 428 {
 429     struct list *bucket = get_hash_list( dev, ino );
 430     struct inode *inode;
 431
 432     LIST_FOR_EACH_ENTRY( inode, bucket, struct inode, ino_entry )
 433         if (inode->ino == ino && inode->dev == dev)
 434              return inode;
 435
 436     return NULL;
 437 }
 438
 439 static struct inode *create_inode( dev_t dev, ino_t ino )
 440 {
 441     struct inode *inode;
 442
 443     inode = malloc( sizeof *inode );
 444     if (inode)
 445     {
 446         list_init( &inode->children );
 447         list_init( &inode->dirs );
 448         inode->ino = ino;
 449         inode->dev = dev;
 450         inode->wd = -1;
 451         inode->parent = NULL;
 452         inode->name = NULL;
 453         list_add_tail( get_hash_list( dev, ino ), &inode->ino_entry );
 454     }
 455     return inode;
 456 }
 457
 458 static struct inode *get_inode( dev_t dev, ino_t ino )
 459 {
 460     struct inode *inode;
 461
 462     inode = find_inode( dev, ino );
 463     if (inode)
 464         return inode;
 465     return create_inode( dev, ino );
 466 }
 467
 468 static void inode_set_wd( struct inode *inode, int wd )
 469 {
 470     if (inode->wd != -1)
 471         list_remove( &inode->wd_entry );
 472     inode->wd = wd;
 473     list_add_tail( &wd_hash[ wd % HASH_SIZE ], &inode->wd_entry );
 474 }
 475
 476 static void inode_set_name( struct inode *inode, const char *name )
 477 {
 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
 555 static const struct fd_ops inotify_fd_ops =
 556 {
 557     inotify_get_poll_events,  /* get_poll_events */
 558     inotify_poll_event,       /* poll_event */
 559     no_flush,                 /* flush */
 560     no_get_file_info,         /* get_file_info */
 561     default_fd_queue_async,   /* queue_async */
 562     default_fd_cancel_async,  /* cancel_async */
 563 };
 564
 565 static int inotify_get_poll_events( struct fd *fd )
 566 {
 567     return POLLIN;
 568 }
 569
 570 static void inotify_do_change_notify( struct dir *dir, unsigned int action,
 571                                       const char *relpath )
 572 {
 573     struct change_record *record;
 574
 575     assert( dir->obj.ops == &dir_ops );
 576
 577     if (dir->want_data)
 578     {
 579         size_t len = strlen(relpath);
 580         record = malloc( offsetof(struct change_record, name[len]) );
 581         if (!record)
 582             return;
 583
 584         record->action = action;
 585         memcpy( record->name, relpath, len );
 586         record->len = len;
 587
 588         list_add_tail( &dir->change_records, &record->entry );
 589     }
 590
 591     if (!list_empty( &dir->change_q ))
 592         async_terminate_head( &dir->change_q, STATUS_ALERTED );
 593 }
 594
 595 static unsigned int filter_from_event( struct inotify_event *ie )
 596 {
 597     unsigned int filter = 0;
 598
 599     if (ie->mask & (IN_MOVED_FROM | IN_MOVED_TO | IN_DELETE | IN_CREATE))
 600         filter |= FILE_NOTIFY_CHANGE_FILE_NAME | FILE_NOTIFY_CHANGE_DIR_NAME;
 601     if (ie->mask & IN_MODIFY)
 602         filter |= FILE_NOTIFY_CHANGE_SIZE | FILE_NOTIFY_CHANGE_LAST_WRITE;
 603     if (ie->mask & IN_ATTRIB)
 604         filter |= FILE_NOTIFY_CHANGE_ATTRIBUTES | FILE_NOTIFY_CHANGE_SECURITY;
 605     if (ie->mask & IN_ACCESS)
 606         filter |= FILE_NOTIFY_CHANGE_LAST_ACCESS;
 607     if (ie->mask & IN_CREATE)
 608         filter |= FILE_NOTIFY_CHANGE_CREATION;
 609
 610     return filter;
 611 }
 612
 613 /* scan up the parent directories for watches */
 614 static unsigned int filter_from_inode( struct inode *inode, int is_parent )
 615 {
 616     unsigned int filter = 0;
 617     struct dir *dir;
 618
 619     /* combine filters from parents watching subtrees */
 620     while (inode)
 621     {
 622         LIST_FOR_EACH_ENTRY( dir, &inode->dirs, struct dir, in_entry )
 623             if (dir->subtree || !is_parent)
 624                 filter |= dir->filter;
 625         is_parent = 1;
 626         inode = inode->parent;
 627     }
 628
 629     return filter;
 630 }
 631
 632 static char *inode_get_path( struct inode *inode, int sz )
 633 {
 634     struct list *head;
 635     char *path;
 636     int len;
 637
 638     if (!inode)
 639         return NULL;
 640
 641     head = list_head( &inode->dirs );
 642     if (head)
 643     {
 644         int unix_fd = get_unix_fd( LIST_ENTRY( head, struct dir, in_entry )->fd );
 645         path = malloc ( 32 + sz );
 646         if (path)
 647             sprintf( path, "/proc/self/fd/%u/", unix_fd );
 648         return path;
 649     }
 650
 651     if (!inode->name)
 652         return NULL;
 653
 654     len = strlen( inode->name );
 655     path = inode_get_path( inode->parent, sz + len + 1 );
 656     if (!path)
 657         return NULL;
 658
 659     strcat( path, inode->name );
 660     strcat( path, "/" );
 661
 662     return path;
 663 }
 664
 665 static int inode_check_dir( struct inode *parent, const char *name )
 666 {
 667     char *path;
 668     unsigned int filter;
 669     struct inode *inode;
 670     struct stat st;
 671     int wd = -1, r = -1;
 672
 673     path = inode_get_path( parent, strlen(name) );
 674     if (!path)
 675         return r;
 676
 677     strcat( path, name );
 678
 679     r = stat( path, &st );
 680     if (r < 0) goto end;
 681
 682     if (!S_ISDIR(st.st_mode))
 683     {
 684         r = 0;
 685         goto end;
 686     }
 687
 688     r = 1;
 689
 690     filter = filter_from_inode( parent, 1 );
 691     if (!filter)
 692         goto end;
 693
 694     inode = inode_add( parent, st.st_dev, st.st_ino, name );
 695     if (!inode || inode->wd != -1)
 696         goto end;
 697
 698     wd = inotify_add_dir( path, filter );
 699     if (wd != -1)
 700         inode_set_wd( inode, wd );
 701     else
 702         free_inode( inode );
 703
 704 end:
 705     free( path );
 706     return r;
 707 }
 708
 709 static int prepend( char **path, const char *segment )
 710 {
 711     int extra;
 712     char *p;
 713
 714     extra = strlen( segment ) + 1;
 715     if (*path)
 716     {
 717         int len = strlen( *path ) + 1;
 718         p = realloc( *path, len + extra );
 719         if (!p) return 0;
 720         memmove( &p[ extra ], p, len );
 721         p[ extra - 1 ] = '/';
 722         memcpy( p, segment, extra - 1 );
 723     }
 724     else
 725     {
 726         p = malloc( extra );
 727         if (!p) return 0;
 728         memcpy( p, segment, extra );
 729     }
 730
 731     *path = p;
 732
 733     return 1;
 734 }
 735
 736 static void inotify_notify_all( struct inotify_event *ie )
 737 {
 738     unsigned int filter, action;
 739     struct inode *inode, *i;
 740     char *path = NULL;
 741     struct dir *dir;
 742
 743     inode = inode_from_wd( ie->wd );
 744     if (!inode)
 745     {
 746         fprintf( stderr, "no inode matches %d\n", ie->wd);
 747         return;
 748     }
 749
 750     filter = filter_from_event( ie );
 751
 752     if (ie->mask & IN_CREATE)
 753     {
 754         switch (inode_check_dir( inode, ie->name ))
 755         {
 756         case 1:
 757             filter &= ~FILE_NOTIFY_CHANGE_FILE_NAME;
 758             break;
 759         case 0:
 760             filter &= ~FILE_NOTIFY_CHANGE_DIR_NAME;
 761             break;
 762         default:
 763             break;
 764             /* Maybe the file disappeared before we could check it? */
 765         }
 766         action = FILE_ACTION_ADDED;
 767     }
 768     else if (ie->mask & IN_DELETE)
 769         action = FILE_ACTION_REMOVED;
 770     else
 771         action = FILE_ACTION_MODIFIED;
 772
 773     /*
 774      * Work our way up the inode hierarchy
 775      *  extending the relative path as we go
 776      *  and notifying all recursive watches.
 777      */
 778     if (!prepend( &path, ie->name ))
 779         return;
 780
 781     for (i = inode; i; i = i->parent)
 782     {
 783         LIST_FOR_EACH_ENTRY( dir, &i->dirs, struct dir, in_entry )
 784             if ((filter & dir->filter) && (i==inode || dir->subtree))
 785                 inotify_do_change_notify( dir, action, path );
 786
 787         if (!i->name || !prepend( &path, i->name ))
 788             break;
 789     }
 790
 791     free( path );
 792
 793     if (ie->mask & IN_DELETE)
 794     {
 795         i = inode_from_name( inode, ie->name );
 796         if (i)
 797             free_inode( i );
 798     }
 799 }
 800
 801 static void inotify_poll_event( struct fd *fd, int event )
 802 {
 803     int r, ofs, unix_fd;
 804     char buffer[0x1000];
 805     struct inotify_event *ie;
 806
 807     unix_fd = get_unix_fd( fd );
 808     r = read( unix_fd, buffer, sizeof buffer );
 809     if (r < 0)
 810     {
 811         fprintf(stderr,"inotify_poll_event(): inotify read failed!\n");
 812         return;
 813     }
 814
 815     for( ofs = 0; ofs < r - offsetof(struct inotify_event, name); )
 816     {
 817         ie = (struct inotify_event*) &buffer[ofs];
 818         if (!ie->len)
 819             break;
 820         ofs += offsetof( struct inotify_event, name[ie->len] );
 821         if (ofs > r) break;
 822         inotify_notify_all( ie );
 823     }
 824 }
 825
 826 static inline struct fd *create_inotify_fd( void )
 827 {
 828     int unix_fd;
 829
 830     unix_fd = inotify_init();
 831     if (unix_fd<0)
 832         return NULL;
 833     return create_anonymous_fd( &inotify_fd_ops, unix_fd, NULL );
 834 }
 835
 836 static int map_flags( unsigned int filter )
 837 {
 838     unsigned int mask;
 839
 840     /* always watch these so we can track subdirectories in recursive watches */
 841     mask = (IN_MOVED_FROM | IN_MOVED_TO | IN_DELETE | IN_CREATE | IN_DELETE_SELF);
 842
 843     if (filter & FILE_NOTIFY_CHANGE_ATTRIBUTES)
 844         mask |= IN_ATTRIB;
 845     if (filter & FILE_NOTIFY_CHANGE_SIZE)
 846         mask |= IN_MODIFY;
 847     if (filter & FILE_NOTIFY_CHANGE_LAST_WRITE)
 848         mask |= IN_MODIFY;
 849     if (filter & FILE_NOTIFY_CHANGE_LAST_ACCESS)
 850         mask |= IN_ACCESS;
 851     if (filter & FILE_NOTIFY_CHANGE_SECURITY)
 852         mask |= IN_ATTRIB;
 853
 854     return mask;
 855 }
 856
 857 static int inotify_add_dir( char *path, unsigned int filter )
 858 {
 859     int wd = inotify_add_watch( get_unix_fd( inotify_fd ),
 860                                 path, map_flags( filter ) );
 861     if (wd != -1)
 862         set_fd_events( inotify_fd, POLLIN );
 863     return wd;
 864 }
 865
 866 static int init_inotify( void )
 867 {
 868     int i;
 869
 870     if (inotify_fd)
 871         return 1;
 872
 873     inotify_fd = create_inotify_fd();
 874     if (!inotify_fd)
 875         return 0;
 876
 877     for (i=0; i<HASH_SIZE; i++)
 878     {
 879         list_init( &inode_hash[i] );
 880         list_init( &wd_hash[i] );
 881     }
 882
 883     return 1;
 884 }
 885
 886 static int inotify_adjust_changes( struct dir *dir )
 887 {
 888     unsigned int filter;
 889     struct inode *inode;
 890     struct stat st;
 891     char path[32];
 892     int wd, unix_fd;
 893
 894     if (!inotify_fd)
 895         return 0;
 896
 897     unix_fd = get_unix_fd( dir->fd );
 898
 899     inode = dir->inode;
 900     if (!inode)
 901     {
 902         /* check if this fd is already being watched */
 903         if (-1 == fstat( unix_fd, &st ))
 904             return 0;
 905
 906         inode = get_inode( st.st_dev, st.st_ino );
 907         if (!inode)
 908             inode = create_inode( st.st_dev, st.st_ino );
 909         if (!inode)
 910             return 0;
 911         list_add_tail( &inode->dirs, &dir->in_entry );
 912         dir->inode = inode;
 913     }
 914
 915     filter = filter_from_inode( inode, 0 );
 916
 917     sprintf( path, "/proc/self/fd/%u", unix_fd );
 918     wd = inotify_add_dir( path, filter );
 919     if (wd == -1) return 0;
 920
 921     inode_set_wd( inode, wd );
 922
 923     return 1;
 924 }
 925
 926 static char *get_basename( const char *link )
 927 {
 928     char *buffer, *name = NULL;
 929     int r, n = 0x100;
 930
 931     while (1)
 932     {
 933         buffer = malloc( n );
 934         if (!buffer) return NULL;
 935
 936         r = readlink( link, buffer, n );
 937         if (r < 0)
 938             break;
 939
 940         if (r < n)
 941         {
 942             name = buffer;
 943             break;
 944         }
 945         free( buffer );
 946         n *= 2;
 947     }
 948
 949     if (name)
 950     {
 951         while (r > 0 && name[ r - 1 ] == '/' )
 952             r--;
 953         name[ r ] = 0;
 954
 955         name = strrchr( name, '/' );
 956         if (name)
 957             name = strdup( &name[1] );
 958     }
 959
 960     free( buffer );
 961     return name;
 962 }
 963
 964 static int dir_add_to_existing_notify( struct dir *dir )
 965 {
 966     struct inode *inode, *parent;
 967     unsigned int filter = 0;
 968     struct stat st, st_new;
 969     char link[35], *name;
 970     int wd, unix_fd;
 971
 972     if (!inotify_fd)
 973         return 0;
 974
 975     unix_fd = get_unix_fd( dir->fd );
 976
 977     /* check if it's in the list of inodes we want to watch */
 978     if (-1 == fstat( unix_fd, &st_new ))
 979         return 0;
 980     inode = find_inode( st_new.st_dev, st_new.st_ino );
 981     if (inode)
 982         return 0;
 983
 984     /* lookup the parent */
 985     sprintf( link, "/proc/self/fd/%u/..", unix_fd );
 986     if (-1 == stat( link, &st ))
 987         return 0;
 988
 989     /*
 990      * If there's no parent, stop.  We could keep going adding
 991      *  ../ to the path until we hit the root of the tree or
 992      *  find a recursively watched ancestor.
 993      * Assume it's too expensive to search up the tree for now.
 994      */
 995     parent = find_inode( st.st_dev, st.st_ino );
 996     if (!parent)
 997         return 0;
 998
 999     if (parent->wd == -1)
1000         return 0;
1001
1002     filter = filter_from_inode( parent, 1 );
1003     if (!filter)
1004         return 0;
1005
1006     sprintf( link, "/proc/self/fd/%u", unix_fd );
1007     name = get_basename( link );
1008     if (!name)
1009         return 0;
1010     inode = inode_add( parent, st_new.st_dev, st_new.st_ino, name );
1011     free( name );
1012     if (!inode)
1013         return 0;
1014
1015     /* Couldn't find this inode at the start of the function, must be new */
1016     assert( inode->wd == -1 );
1017
1018     wd = inotify_add_dir( link, filter );
1019     if (wd != -1)
1020         inode_set_wd( inode, wd );
1021
1022     return 1;
1023 }
1024
1025 #else
1026
1027 static int init_inotify( void )
1028 {
1029     return 0;
1030 }
1031
1032 static int inotify_adjust_changes( struct dir *dir )
1033 {
1034     return 0;
1035 }
1036
1037 static void free_inode( struct inode *inode )
1038 {
1039     assert( 0 );
1040 }
1041
1042 static int dir_add_to_existing_notify( struct dir *dir )
1043 {
1044     return 0;
1045 }
1046
1047 #endif  /* USE_INOTIFY */
1048
1049 struct object *create_dir_obj( struct fd *fd )
1050 {
1051     struct dir *dir;
1052
1053     dir = alloc_object( &dir_ops );
1054     if (!dir)
1055         return NULL;
1056
1057     list_init( &dir->change_q );
1058     list_init( &dir->change_records );
1059     dir->event = NULL;
1060     dir->filter = 0;
1061     dir->notified = 0;
1062     dir->signaled = 0;
1063     dir->want_data = 0;
1064     dir->inode = NULL;
1065     grab_object( fd );
1066     dir->fd = fd;
1067     set_fd_user( fd, &dir_fd_ops, &dir->obj );
1068
1069     dir_add_to_existing_notify( dir );
1070
1071     return &dir->obj;
1072 }
1073
1074 /* enable change notifications for a directory */
1075 DECL_HANDLER(read_directory_changes)
1076 {
1077     struct event *event = NULL;
1078     struct dir *dir;
1079
1080     if (!req->filter)
1081     {
1082         set_error(STATUS_INVALID_PARAMETER);
1083         return;
1084     }
1085
1086     dir = get_dir_obj( current->process, req->handle, 0 );
1087     if (!dir)
1088         return;
1089
1090     /* possibly send changes through an event flag */
1091     if (req->event)
1092     {
1093         event = get_event_obj( current->process, req->event, EVENT_MODIFY_STATE );
1094         if (!event)
1095             goto end;
1096     }
1097
1098     /* discard the current data, and move onto the next event */
1099     if (dir->event) release_object( dir->event );
1100     dir->event = event;
1101
1102     /* requests don't timeout */
1103     if ( req->io_apc && !create_async( current, NULL, &dir->change_q,
1104                         req->io_apc, req->io_user, req->io_sb ))
1105         return;
1106
1107     /* assign it once */
1108     if (!dir->filter)
1109     {
1110         init_inotify();
1111         insert_change( dir );
1112         dir->filter = req->filter;
1113         dir->subtree = req->subtree;
1114         dir->want_data = req->want_data;
1115     }
1116
1117     /* remove any notifications */
1118     if (dir->signaled>0)
1119         dir->signaled--;
1120
1121     /* clear the event */
1122     if (event)
1123         reset_event( event );
1124
1125     /* if there's already a change in the queue, send it */
1126     if (!list_empty( &dir->change_q ) &&
1127         !list_empty( &dir->change_records ))
1128         async_terminate_head( &dir->change_q, STATUS_ALERTED );
1129
1130     /* setup the real notification */
1131     if (!inotify_adjust_changes( dir ))
1132         dnotify_adjust_changes( dir );
1133
1134     set_error(STATUS_PENDING);
1135
1136 end:
1137     release_object( dir );
1138 }
1139
1140 DECL_HANDLER(read_change)
1141 {
1142     struct change_record *record;
1143     struct dir *dir;
1144
1145     dir = get_dir_obj( current->process, req->handle, 0 );
1146     if (!dir)
1147         return;
1148
1149     if ((record = get_first_change_record( dir )) != NULL)
1150     {
1151         reply->action = record->action;
1152         set_reply_data( record->name, record->len );
1153         free( record );
1154     }
1155     else
1156         set_error( STATUS_NO_DATA_DETECTED );
1157
1158     /* now signal it */
1159     dir->signaled++;
1160     dir_signal_changed( dir );
1161
1162     release_object( dir );
1163 }