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     no_open_file,             /* open_file */
 181     fd_close_handle,          /* close_handle */
 182     dir_destroy               /* destroy */
 183 };
 184
 185 static int dir_get_poll_events( struct fd *fd );
 186 static enum server_fd_type dir_get_info( struct fd *fd, int *flags );
 187 static void dir_cancel_async( struct fd *fd );
 188
 189 static const struct fd_ops dir_fd_ops =
 190 {
 191     dir_get_poll_events,      /* get_poll_events */
 192     default_poll_event,       /* poll_event */
 193     no_flush,                 /* flush */
 194     dir_get_info,             /* get_file_info */
 195     default_fd_queue_async,   /* queue_async */
 196     dir_cancel_async          /* cancel_async */
 197 };
 198
 199 static struct list change_list = LIST_INIT(change_list);
 200
 201 static void dnotify_adjust_changes( struct dir *dir )
 202 {
 203 #if defined(F_SETSIG) && defined(F_NOTIFY)
 204     int fd = get_unix_fd( dir->fd );
 205     unsigned int filter = dir->filter;
 206     unsigned int val;
 207     if ( 0 > fcntl( fd, F_SETSIG, SIGIO) )
 208         return;
 209
 210     val = DN_MULTISHOT;
 211     if (filter & FILE_NOTIFY_CHANGE_FILE_NAME)
 212         val |= DN_RENAME | DN_DELETE | DN_CREATE;
 213     if (filter & FILE_NOTIFY_CHANGE_DIR_NAME)
 214         val |= DN_RENAME | DN_DELETE | DN_CREATE;
 215     if (filter & FILE_NOTIFY_CHANGE_ATTRIBUTES)
 216         val |= DN_ATTRIB;
 217     if (filter & FILE_NOTIFY_CHANGE_SIZE)
 218         val |= DN_MODIFY;
 219     if (filter & FILE_NOTIFY_CHANGE_LAST_WRITE)
 220         val |= DN_MODIFY;
 221     if (filter & FILE_NOTIFY_CHANGE_LAST_ACCESS)
 222         val |= DN_ACCESS;
 223     if (filter & FILE_NOTIFY_CHANGE_CREATION)
 224         val |= DN_CREATE;
 225     if (filter & FILE_NOTIFY_CHANGE_SECURITY)
 226         val |= DN_ATTRIB;
 227     fcntl( fd, F_NOTIFY, val );
 228 #endif
 229 }
 230
 231 /* insert change in the global list */
 232 static inline void insert_change( struct dir *dir )
 233 {
 234     sigset_t sigset;
 235
 236     sigemptyset( &sigset );
 237     sigaddset( &sigset, SIGIO );
 238     sigprocmask( SIG_BLOCK, &sigset, NULL );
 239     list_add_head( &change_list, &dir->entry );
 240     sigprocmask( SIG_UNBLOCK, &sigset, NULL );
 241 }
 242
 243 /* remove change from the global list */
 244 static inline void remove_change( struct dir *dir )
 245 {
 246     sigset_t sigset;
 247
 248     sigemptyset( &sigset );
 249     sigaddset( &sigset, SIGIO );
 250     sigprocmask( SIG_BLOCK, &sigset, NULL );
 251     list_remove( &dir->entry );
 252     sigprocmask( SIG_UNBLOCK, &sigset, NULL );
 253 }
 254
 255 static void dir_dump( struct object *obj, int verbose )
 256 {
 257     struct dir *dir = (struct dir *)obj;
 258     assert( obj->ops == &dir_ops );
 259     fprintf( stderr, "Dirfile fd=%p event=%p filter=%08x\n",
 260              dir->fd, dir->event, dir->filter );
 261 }
 262
 263 static int dir_signaled( struct object *obj, struct thread *thread )
 264 {
 265     struct dir *dir = (struct dir *)obj;
 266     assert (obj->ops == &dir_ops);
 267     return (dir->event == NULL) && dir->signaled;
 268 }
 269
 270 /* enter here directly from SIGIO signal handler */
 271 void do_change_notify( int unix_fd )
 272 {
 273     struct dir *dir;
 274
 275     /* FIXME: this is O(n) ... probably can be improved */
 276     LIST_FOR_EACH_ENTRY( dir, &change_list, struct dir, entry )
 277     {
 278         if (get_unix_fd( dir->fd ) != unix_fd) continue;
 279         interlocked_xchg_add( &dir->notified, 1 );
 280         break;
 281     }
 282 }
 283
 284 static void dir_signal_changed( struct dir *dir )
 285 {
 286     if (!dir->event) wake_up( &dir->obj, 0 );
 287 }
 288
 289 /* SIGIO callback, called synchronously with the poll loop */
 290 void sigio_callback(void)
 291 {
 292     struct dir *dir;
 293
 294     LIST_FOR_EACH_ENTRY( dir, &change_list, struct dir, entry )
 295     {
 296         long count = interlocked_xchg( &dir->notified, 0 );
 297         if (count)
 298         {
 299             dir->signaled += count;
 300             if (dir->signaled == count)  /* was it 0? */
 301                 dir_signal_changed( dir );
 302         }
 303     }
 304 }
 305
 306 static struct fd *dir_get_fd( struct object *obj )
 307 {
 308     struct dir *dir = (struct dir *)obj;
 309     assert( obj->ops == &dir_ops );
 310     return (struct fd *)grab_object( dir->fd );
 311 }
 312
 313 static unsigned int dir_map_access( struct object *obj, unsigned int access )
 314 {
 315     if (access & GENERIC_READ)    access |= FILE_GENERIC_READ;
 316     if (access & GENERIC_WRITE)   access |= FILE_GENERIC_WRITE;
 317     if (access & GENERIC_EXECUTE) access |= FILE_GENERIC_EXECUTE;
 318     if (access & GENERIC_ALL)     access |= FILE_ALL_ACCESS;
 319     return access & ~(GENERIC_READ | GENERIC_WRITE | GENERIC_EXECUTE | GENERIC_ALL);
 320 }
 321
 322 static struct change_record *get_first_change_record( struct dir *dir )
 323 {
 324     struct list *ptr = list_head( &dir->change_records );
 325     if (!ptr) return NULL;
 326     list_remove( ptr );
 327     return LIST_ENTRY( ptr, struct change_record, entry );
 328 }
 329
 330 static void dir_destroy( struct object *obj )
 331 {
 332     struct change_record *record;
 333     struct dir *dir = (struct dir *)obj;
 334     assert (obj->ops == &dir_ops);
 335
 336     if (dir->filter)
 337         remove_change( dir );
 338
 339     if (dir->inode)
 340     {
 341         list_remove( &dir->in_entry );
 342         free_inode( dir->inode );
 343     }
 344
 345     async_terminate_queue( &dir->change_q, STATUS_CANCELLED );
 346     while ((record = get_first_change_record( dir ))) free( record );
 347
 348     if (dir->event) release_object( dir->event );
 349     release_object( dir->fd );
 350
 351     if (inotify_fd && list_empty( &change_list ))
 352     {
 353         release_object( inotify_fd );
 354         inotify_fd = NULL;
 355     }
 356 }
 357
 358 static struct dir *
 359 get_dir_obj( struct process *process, obj_handle_t handle, unsigned int access )
 360 {
 361     return (struct dir *)get_handle_obj( process, handle, access, &dir_ops );
 362 }
 363
 364 static int dir_get_poll_events( struct fd *fd )
 365 {
 366     return 0;
 367 }
 368
 369 static enum server_fd_type dir_get_info( struct fd *fd, int *flags )
 370 {
 371     *flags = 0;
 372     return FD_TYPE_DIR;
 373 }
 374
 375 static void dir_cancel_async( struct fd *fd )
 376 {
 377     struct dir *dir = (struct dir *) get_fd_user( fd );
 378     async_terminate_queue( &dir->change_q, STATUS_CANCELLED );
 379 }
 380
 381
 382 #ifdef USE_INOTIFY
 383
 384 #define HASH_SIZE 31
 385
 386 struct inode {
 387     struct list ch_entry;    /* entry in the children list */
 388     struct list children;    /* children of this inode */
 389     struct inode *parent;    /* parent of this inode */
 390     struct list dirs;        /* directory handles watching this inode */
 391     struct list ino_entry;   /* entry in the inode hash */
 392     struct list wd_entry;    /* entry in the watch descriptor hash */
 393     dev_t dev;               /* device number */
 394     ino_t ino;               /* device's inode number */
 395     int wd;                  /* inotify's watch descriptor */
 396     char *name;              /* basename name of the inode */
 397 };
 398
 399 struct list inode_hash[ HASH_SIZE ];
 400 struct list wd_hash[ HASH_SIZE ];
 401
 402 static int inotify_add_dir( char *path, unsigned int filter );
 403
 404 static struct inode *inode_from_wd( int wd )
 405 {
 406     struct list *bucket = &wd_hash[ wd % HASH_SIZE ];
 407     struct inode *inode;
 408
 409     LIST_FOR_EACH_ENTRY( inode, bucket, struct inode, wd_entry )
 410         if (inode->wd == wd)
 411             return inode;
 412
 413     return NULL;
 414 }
 415
 416 static inline struct list *get_hash_list( dev_t dev, ino_t ino )
 417 {
 418     return &inode_hash[ (ino ^ dev) % HASH_SIZE ];
 419 }
 420
 421 static struct inode *find_inode( dev_t dev, ino_t ino )
 422 {
 423     struct list *bucket = get_hash_list( dev, ino );
 424     struct inode *inode;
 425
 426     LIST_FOR_EACH_ENTRY( inode, bucket, struct inode, ino_entry )
 427         if (inode->ino == ino && inode->dev == dev)
 428              return inode;
 429
 430     return NULL;
 431 }
 432
 433 static struct inode *create_inode( dev_t dev, ino_t ino )
 434 {
 435     struct inode *inode;
 436
 437     inode = malloc( sizeof *inode );
 438     if (inode)
 439     {
 440         list_init( &inode->children );
 441         list_init( &inode->dirs );
 442         inode->ino = ino;
 443         inode->dev = dev;
 444         inode->wd = -1;
 445         inode->parent = NULL;
 446         inode->name = NULL;
 447         list_add_tail( get_hash_list( dev, ino ), &inode->ino_entry );
 448     }
 449     return inode;
 450 }
 451
 452 static struct inode *get_inode( dev_t dev, ino_t ino )
 453 {
 454     struct inode *inode;
 455
 456     inode = find_inode( dev, ino );
 457     if (inode)
 458         return inode;
 459     return create_inode( dev, ino );
 460 }
 461
 462 static void inode_set_wd( struct inode *inode, int wd )
 463 {
 464     if (inode->wd != -1)
 465         list_remove( &inode->wd_entry );
 466     inode->wd = wd;
 467     list_add_tail( &wd_hash[ wd % HASH_SIZE ], &inode->wd_entry );
 468 }
 469
 470 static void inode_set_name( struct inode *inode, const char *name )
 471 {
 472     free (inode->name);
 473     inode->name = name ? strdup( name ) : NULL;
 474 }
 475
 476 static void free_inode( struct inode *inode )
 477 {
 478     int subtree = 0, watches = 0;
 479     struct dir *dir;
 480
 481     LIST_FOR_EACH_ENTRY( dir, &inode->dirs, struct dir, in_entry )
 482     {
 483         subtree |= dir->subtree;
 484         watches++;
 485     }
 486
 487     if (!subtree && !inode->parent)
 488     {
 489         struct inode *tmp, *next;
 490         LIST_FOR_EACH_ENTRY_SAFE( tmp, next, &inode->children,
 491                                   struct inode, ch_entry )
 492         {
 493             assert( tmp != inode );
 494             assert( tmp->parent == inode );
 495             free_inode( tmp );
 496         }
 497     }
 498
 499     if (watches)
 500         return;
 501
 502     if (inode->parent)
 503         list_remove( &inode->ch_entry );
 504
 505     if (inode->wd != -1)
 506     {
 507         inotify_remove_watch( get_unix_fd( inotify_fd ), inode->wd );
 508         list_remove( &inode->wd_entry );
 509     }
 510     list_remove( &inode->ino_entry );
 511
 512     free( inode->name );
 513     free( inode );
 514 }
 515
 516 static struct inode *inode_add( struct inode *parent,
 517                                 dev_t dev, ino_t ino, const char *name )
 518 {
 519     struct inode *inode;
 520
 521     inode = get_inode( dev, ino );
 522     if (!inode)
 523         return NULL;
 524
 525     if (!inode->parent)
 526     {
 527         list_add_tail( &parent->children, &inode->ch_entry );
 528         inode->parent = parent;
 529         assert( inode != parent );
 530     }
 531     inode_set_name( inode, name );
 532
 533     return inode;
 534 }
 535
 536 static struct inode *inode_from_name( struct inode *inode, const char *name )
 537 {
 538     struct inode *i;
 539
 540     LIST_FOR_EACH_ENTRY( i, &inode->children, struct inode, ch_entry )
 541         if (i->name && !strcmp( i->name, name ))
 542             return i;
 543     return NULL;
 544 }
 545
 546 static int inotify_get_poll_events( struct fd *fd );
 547 static void inotify_poll_event( struct fd *fd, int event );
 548
 549 static const struct fd_ops inotify_fd_ops =
 550 {
 551     inotify_get_poll_events,  /* get_poll_events */
 552     inotify_poll_event,       /* poll_event */
 553     no_flush,                 /* flush */
 554     no_get_file_info,         /* get_file_info */
 555     default_fd_queue_async,   /* queue_async */
 556     default_fd_cancel_async,  /* cancel_async */
 557 };
 558
 559 static int inotify_get_poll_events( struct fd *fd )
 560 {
 561     return POLLIN;
 562 }
 563
 564 static void inotify_do_change_notify( struct dir *dir, unsigned int action,
 565                                       const char *relpath )
 566 {
 567     struct change_record *record;
 568
 569     assert( dir->obj.ops == &dir_ops );
 570
 571     if (dir->want_data)
 572     {
 573         size_t len = strlen(relpath);
 574         record = malloc( offsetof(struct change_record, name[len]) );
 575         if (!record)
 576             return;
 577
 578         record->action = action;
 579         memcpy( record->name, relpath, len );
 580         record->len = len;
 581
 582         list_add_tail( &dir->change_records, &record->entry );
 583     }
 584
 585     if (!list_empty( &dir->change_q ))
 586         async_terminate_head( &dir->change_q, STATUS_ALERTED );
 587 }
 588
 589 static unsigned int filter_from_event( struct inotify_event *ie )
 590 {
 591     unsigned int filter = 0;
 592
 593     if (ie->mask & (IN_MOVED_FROM | IN_MOVED_TO | IN_DELETE | IN_CREATE))
 594         filter |= FILE_NOTIFY_CHANGE_FILE_NAME | FILE_NOTIFY_CHANGE_DIR_NAME;
 595     if (ie->mask & IN_MODIFY)
 596         filter |= FILE_NOTIFY_CHANGE_SIZE | FILE_NOTIFY_CHANGE_LAST_WRITE;
 597     if (ie->mask & IN_ATTRIB)
 598         filter |= FILE_NOTIFY_CHANGE_ATTRIBUTES | FILE_NOTIFY_CHANGE_SECURITY;
 599     if (ie->mask & IN_ACCESS)
 600         filter |= FILE_NOTIFY_CHANGE_LAST_ACCESS;
 601     if (ie->mask & IN_CREATE)
 602         filter |= FILE_NOTIFY_CHANGE_CREATION;
 603
 604     return filter;
 605 }
 606
 607 /* scan up the parent directories for watches */
 608 static unsigned int filter_from_inode( struct inode *inode, int is_parent )
 609 {
 610     unsigned int filter = 0;
 611     struct dir *dir;
 612
 613     /* combine filters from parents watching subtrees */
 614     while (inode)
 615     {
 616         LIST_FOR_EACH_ENTRY( dir, &inode->dirs, struct dir, in_entry )
 617             if (dir->subtree || !is_parent)
 618                 filter |= dir->filter;
 619         is_parent = 1;
 620         inode = inode->parent;
 621     }
 622
 623     return filter;
 624 }
 625
 626 static char *inode_get_path( struct inode *inode, int sz )
 627 {
 628     struct list *head;
 629     char *path;
 630     int len;
 631
 632     if (!inode)
 633         return NULL;
 634
 635     head = list_head( &inode->dirs );
 636     if (head)
 637     {
 638         int unix_fd = get_unix_fd( LIST_ENTRY( head, struct dir, in_entry )->fd );
 639         path = malloc ( 32 + sz );
 640         if (path)
 641             sprintf( path, "/proc/self/fd/%u/", unix_fd );
 642         return path;
 643     }
 644
 645     if (!inode->name)
 646         return NULL;
 647
 648     len = strlen( inode->name );
 649     path = inode_get_path( inode->parent, sz + len + 1 );
 650     if (!path)
 651         return NULL;
 652
 653     strcat( path, inode->name );
 654     strcat( path, "/" );
 655
 656     return path;
 657 }
 658
 659 static int inode_check_dir( struct inode *parent, const char *name )
 660 {
 661     char *path;
 662     unsigned int filter;
 663     struct inode *inode;
 664     struct stat st;
 665     int wd = -1, r = -1;
 666
 667     path = inode_get_path( parent, strlen(name) );
 668     if (!path)
 669         return r;
 670
 671     strcat( path, name );
 672
 673     r = stat( path, &st );
 674     if (r < 0) goto end;
 675
 676     if (!S_ISDIR(st.st_mode))
 677     {
 678         r = 0;
 679         goto end;
 680     }
 681
 682     r = 1;
 683
 684     filter = filter_from_inode( parent, 1 );
 685     if (!filter)
 686         goto end;
 687
 688     inode = inode_add( parent, st.st_dev, st.st_ino, name );
 689     if (!inode || inode->wd != -1)
 690         goto end;
 691
 692     wd = inotify_add_dir( path, filter );
 693     if (wd != -1)
 694         inode_set_wd( inode, wd );
 695     else
 696         free_inode( inode );
 697
 698 end:
 699     free( path );
 700     return r;
 701 }
 702
 703 static int prepend( char **path, const char *segment )
 704 {
 705     int extra;
 706     char *p;
 707
 708     extra = strlen( segment ) + 1;
 709     if (*path)
 710     {
 711         int len = strlen( *path ) + 1;
 712         p = realloc( *path, len + extra );
 713         if (!p) return 0;
 714         memmove( &p[ extra ], p, len );
 715         p[ extra - 1 ] = '/';
 716         memcpy( p, segment, extra - 1 );
 717     }
 718     else
 719     {
 720         p = malloc( extra );
 721         if (!p) return 0;
 722         memcpy( p, segment, extra );
 723     }
 724
 725     *path = p;
 726
 727     return 1;
 728 }
 729
 730 static void inotify_notify_all( struct inotify_event *ie )
 731 {
 732     unsigned int filter, action;
 733     struct inode *inode, *i;
 734     char *path = NULL;
 735     struct dir *dir;
 736
 737     inode = inode_from_wd( ie->wd );
 738     if (!inode)
 739     {
 740         fprintf( stderr, "no inode matches %d\n", ie->wd);
 741         return;
 742     }
 743
 744     filter = filter_from_event( ie );
 745
 746     if (ie->mask & IN_CREATE)
 747     {
 748         switch (inode_check_dir( inode, ie->name ))
 749         {
 750         case 1:
 751             filter &= ~FILE_NOTIFY_CHANGE_FILE_NAME;
 752             break;
 753         case 0:
 754             filter &= ~FILE_NOTIFY_CHANGE_DIR_NAME;
 755             break;
 756         default:
 757             break;
 758             /* Maybe the file disappeared before we could check it? */
 759         }
 760         action = FILE_ACTION_ADDED;
 761     }
 762     else if (ie->mask & IN_DELETE)
 763         action = FILE_ACTION_REMOVED;
 764     else
 765         action = FILE_ACTION_MODIFIED;
 766
 767     /*
 768      * Work our way up the inode hierarchy
 769      *  extending the relative path as we go
 770      *  and notifying all recursive watches.
 771      */
 772     if (!prepend( &path, ie->name ))
 773         return;
 774
 775     for (i = inode; i; i = i->parent)
 776     {
 777         LIST_FOR_EACH_ENTRY( dir, &i->dirs, struct dir, in_entry )
 778             if ((filter & dir->filter) && (i==inode || dir->subtree))
 779                 inotify_do_change_notify( dir, action, path );
 780
 781         if (!i->name || !prepend( &path, i->name ))
 782             break;
 783     }
 784
 785     free( path );
 786
 787     if (ie->mask & IN_DELETE)
 788     {
 789         i = inode_from_name( inode, ie->name );
 790         if (i)
 791             free_inode( i );
 792     }
 793 }
 794
 795 static void inotify_poll_event( struct fd *fd, int event )
 796 {
 797     int r, ofs, unix_fd;
 798     char buffer[0x1000];
 799     struct inotify_event *ie;
 800
 801     unix_fd = get_unix_fd( fd );
 802     r = read( unix_fd, buffer, sizeof buffer );
 803     if (r < 0)
 804     {
 805         fprintf(stderr,"inotify_poll_event(): inotify read failed!\n");
 806         return;
 807     }
 808
 809     for( ofs = 0; ofs < r - offsetof(struct inotify_event, name); )
 810     {
 811         ie = (struct inotify_event*) &buffer[ofs];
 812         if (!ie->len)
 813             break;
 814         ofs += offsetof( struct inotify_event, name[ie->len] );
 815         if (ofs > r) break;
 816         inotify_notify_all( ie );
 817     }
 818 }
 819
 820 static inline struct fd *create_inotify_fd( void )
 821 {
 822     int unix_fd;
 823
 824     unix_fd = inotify_init();
 825     if (unix_fd<0)
 826         return NULL;
 827     return create_anonymous_fd( &inotify_fd_ops, unix_fd, NULL );
 828 }
 829
 830 static int map_flags( unsigned int filter )
 831 {
 832     unsigned int mask;
 833
 834     /* always watch these so we can track subdirectories in recursive watches */
 835     mask = (IN_MOVED_FROM | IN_MOVED_TO | IN_DELETE | IN_CREATE | IN_DELETE_SELF);
 836
 837     if (filter & FILE_NOTIFY_CHANGE_ATTRIBUTES)
 838         mask |= IN_ATTRIB;
 839     if (filter & FILE_NOTIFY_CHANGE_SIZE)
 840         mask |= IN_MODIFY;
 841     if (filter & FILE_NOTIFY_CHANGE_LAST_WRITE)
 842         mask |= IN_MODIFY;
 843     if (filter & FILE_NOTIFY_CHANGE_LAST_ACCESS)
 844         mask |= IN_ACCESS;
 845     if (filter & FILE_NOTIFY_CHANGE_SECURITY)
 846         mask |= IN_ATTRIB;
 847
 848     return mask;
 849 }
 850
 851 static int inotify_add_dir( char *path, unsigned int filter )
 852 {
 853     int wd = inotify_add_watch( get_unix_fd( inotify_fd ),
 854                                 path, map_flags( filter ) );
 855     if (wd != -1)
 856         set_fd_events( inotify_fd, POLLIN );
 857     return wd;
 858 }
 859
 860 static int init_inotify( void )
 861 {
 862     int i;
 863
 864     if (inotify_fd)
 865         return 1;
 866
 867     inotify_fd = create_inotify_fd();
 868     if (!inotify_fd)
 869         return 0;
 870
 871     for (i=0; i<HASH_SIZE; i++)
 872     {
 873         list_init( &inode_hash[i] );
 874         list_init( &wd_hash[i] );
 875     }
 876
 877     return 1;
 878 }
 879
 880 static int inotify_adjust_changes( struct dir *dir )
 881 {
 882     unsigned int filter;
 883     struct inode *inode;
 884     struct stat st;
 885     char path[32];
 886     int wd, unix_fd;
 887
 888     if (!inotify_fd)
 889         return 0;
 890
 891     unix_fd = get_unix_fd( dir->fd );
 892
 893     inode = dir->inode;
 894     if (!inode)
 895     {
 896         /* check if this fd is already being watched */
 897         if (-1 == fstat( unix_fd, &st ))
 898             return 0;
 899
 900         inode = get_inode( st.st_dev, st.st_ino );
 901         if (!inode)
 902             inode = create_inode( st.st_dev, st.st_ino );
 903         if (!inode)
 904             return 0;
 905         list_add_tail( &inode->dirs, &dir->in_entry );
 906         dir->inode = inode;
 907     }
 908
 909     filter = filter_from_inode( inode, 0 );
 910
 911     sprintf( path, "/proc/self/fd/%u", unix_fd );
 912     wd = inotify_add_dir( path, filter );
 913     if (wd == -1) return 0;
 914
 915     inode_set_wd( inode, wd );
 916
 917     return 1;
 918 }
 919
 920 static char *get_basename( const char *link )
 921 {
 922     char *buffer, *name = NULL;
 923     int r, n = 0x100;
 924
 925     while (1)
 926     {
 927         buffer = malloc( n );
 928         if (!buffer) return NULL;
 929
 930         r = readlink( link, buffer, n );
 931         if (r < 0)
 932             break;
 933
 934         if (r < n)
 935         {
 936             name = buffer;
 937             break;
 938         }
 939         free( buffer );
 940         n *= 2;
 941     }
 942
 943     if (name)
 944     {
 945         while (r > 0 && name[ r - 1 ] == '/' )
 946             r--;
 947         name[ r ] = 0;
 948
 949         name = strrchr( name, '/' );
 950         if (name)
 951             name = strdup( &name[1] );
 952     }
 953
 954     free( buffer );
 955     return name;
 956 }
 957
 958 static int dir_add_to_existing_notify( struct dir *dir )
 959 {
 960     struct inode *inode, *parent;
 961     unsigned int filter = 0;
 962     struct stat st, st_new;
 963     char link[35], *name;
 964     int wd, unix_fd;
 965
 966     if (!inotify_fd)
 967         return 0;
 968
 969     unix_fd = get_unix_fd( dir->fd );
 970
 971     /* check if it's in the list of inodes we want to watch */
 972     if (-1 == fstat( unix_fd, &st_new ))
 973         return 0;
 974     inode = find_inode( st_new.st_dev, st_new.st_ino );
 975     if (inode)
 976         return 0;
 977
 978     /* lookup the parent */
 979     sprintf( link, "/proc/self/fd/%u/..", unix_fd );
 980     if (-1 == stat( link, &st ))
 981         return 0;
 982
 983     /*
 984      * If there's no parent, stop.  We could keep going adding
 985      *  ../ to the path until we hit the root of the tree or
 986      *  find a recursively watched ancestor.
 987      * Assume it's too expensive to search up the tree for now.
 988      */
 989     parent = find_inode( st.st_dev, st.st_ino );
 990     if (!parent)
 991         return 0;
 992
 993     if (parent->wd == -1)
 994         return 0;
 995
 996     filter = filter_from_inode( parent, 1 );
 997     if (!filter)
 998         return 0;
 999
1000     sprintf( link, "/proc/self/fd/%u", unix_fd );
1001     name = get_basename( link );
1002     if (!name)
1003         return 0;
1004     inode = inode_add( parent, st_new.st_dev, st_new.st_ino, name );
1005     free( name );
1006     if (!inode)
1007         return 0;
1008
1009     /* Couldn't find this inode at the start of the function, must be new */
1010     assert( inode->wd == -1 );
1011
1012     wd = inotify_add_dir( link, filter );
1013     if (wd != -1)
1014         inode_set_wd( inode, wd );
1015
1016     return 1;
1017 }
1018
1019 #else
1020
1021 static int init_inotify( void )
1022 {
1023     return 0;
1024 }
1025
1026 static int inotify_adjust_changes( struct dir *dir )
1027 {
1028     return 0;
1029 }
1030
1031 static void free_inode( struct inode *inode )
1032 {
1033     assert( 0 );
1034 }
1035
1036 static int dir_add_to_existing_notify( struct dir *dir )
1037 {
1038     return 0;
1039 }
1040
1041 #endif  /* USE_INOTIFY */
1042
1043 struct object *create_dir_obj( struct fd *fd )
1044 {
1045     struct dir *dir;
1046
1047     dir = alloc_object( &dir_ops );
1048     if (!dir)
1049         return NULL;
1050
1051     list_init( &dir->change_q );
1052     list_init( &dir->change_records );
1053     dir->event = NULL;
1054     dir->filter = 0;
1055     dir->notified = 0;
1056     dir->signaled = 0;
1057     dir->want_data = 0;
1058     dir->inode = NULL;
1059     grab_object( fd );
1060     dir->fd = fd;
1061     set_fd_user( fd, &dir_fd_ops, &dir->obj );
1062
1063     dir_add_to_existing_notify( dir );
1064
1065     return &dir->obj;
1066 }
1067
1068 /* enable change notifications for a directory */
1069 DECL_HANDLER(read_directory_changes)
1070 {
1071     struct event *event = NULL;
1072     struct dir *dir;
1073
1074     if (!req->filter)
1075     {
1076         set_error(STATUS_INVALID_PARAMETER);
1077         return;
1078     }
1079
1080     dir = get_dir_obj( current->process, req->handle, 0 );
1081     if (!dir)
1082         return;
1083
1084     /* possibly send changes through an event flag */
1085     if (req->async.event &&
1086         !(event = get_event_obj( current->process, req->async.event, EVENT_MODIFY_STATE )))
1087         goto end;
1088
1089     /* discard the current data, and move onto the next event */
1090     if (dir->event) release_object( dir->event );
1091     dir->event = event;
1092
1093     /* requests don't timeout */
1094     if (!create_async( current, NULL, &dir->change_q, &req->async )) goto end;
1095
1096     /* assign it once */
1097     if (!dir->filter)
1098     {
1099         init_inotify();
1100         insert_change( dir );
1101         dir->filter = req->filter;
1102         dir->subtree = req->subtree;
1103         dir->want_data = req->want_data;
1104     }
1105
1106     /* remove any notifications */
1107     if (dir->signaled>0)
1108         dir->signaled--;
1109
1110     /* if there's already a change in the queue, send it */
1111     if (!list_empty( &dir->change_q ) &&
1112         !list_empty( &dir->change_records ))
1113         async_terminate_head( &dir->change_q, STATUS_ALERTED );
1114
1115     /* setup the real notification */
1116     if (!inotify_adjust_changes( dir ))
1117         dnotify_adjust_changes( dir );
1118
1119     set_error(STATUS_PENDING);
1120
1121 end:
1122     release_object( dir );
1123 }
1124
1125 DECL_HANDLER(read_change)
1126 {
1127     struct change_record *record;
1128     struct dir *dir;
1129
1130     dir = get_dir_obj( current->process, req->handle, 0 );
1131     if (!dir)
1132         return;
1133
1134     if ((record = get_first_change_record( dir )) != NULL)
1135     {
1136         reply->action = record->action;
1137         set_reply_data( record->name, record->len );
1138         free( record );
1139     }
1140     else
1141         set_error( STATUS_NO_DATA_DETECTED );
1142
1143     /* now signal it */
1144     dir->signaled++;
1145     dir_signal_changed( dir );
1146
1147     release_object( dir );
1148 }