source: trunk/libtransmission/fdlimit.c @ 9328

Last change on this file since 9328 was 9328, checked in by charles, 12 years ago

(trunk) #1483: move completed torrents to a user-specified directory + #629: different file extension for incomplete files

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File size: 17.6 KB
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1/******************************************************************************
2 * $Id: fdlimit.c 9328 2009-10-19 05:05:00Z charles $
3 *
4 * Copyright (c) 2005-2008 Transmission authors and contributors
5 *
6 * Permission is hereby granted, free of charge, to any person obtaining a
7 * copy of this software and associated documentation files (the "Software"),
8 * to deal in the Software without restriction, including without limitation
9 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
10 * and/or sell copies of the Software, and to permit persons to whom the
11 * Software is furnished to do so, subject to the following conditions:
12 *
13 * The above copyright notice and this permission notice shall be included in
14 * all copies or substantial portions of the Software.
15 *
16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
19 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
21 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
22 * DEALINGS IN THE SOFTWARE.
23 *****************************************************************************/
24
25#ifndef WIN32
26 #define HAVE_GETRLIMIT
27#endif
28
29#ifdef HAVE_POSIX_FADVISE
30 #ifdef _XOPEN_SOURCE
31  #undef _XOPEN_SOURCE
32 #endif
33 #define _XOPEN_SOURCE 600
34#endif
35
36#include <assert.h>
37#include <errno.h>
38#include <inttypes.h>
39#include <stdio.h>
40#include <stdlib.h>
41#include <string.h>
42#ifdef SYS_DARWIN
43 #include <fcntl.h>
44#endif
45
46#ifdef HAVE_XFS_XFS_H
47 #include <xfs/xfs.h>
48#endif
49
50#include <sys/types.h>
51#include <sys/stat.h>
52#ifdef HAVE_GETRLIMIT
53 #include <sys/time.h> /* getrlimit */
54 #include <sys/resource.h> /* getrlimit */
55#endif
56#include <unistd.h>
57#include <fcntl.h> /* O_LARGEFILE posix_fadvise */
58
59#include <evutil.h>
60
61#include "transmission.h"
62#include "fdlimit.h"
63#include "list.h"
64#include "net.h"
65#include "platform.h" /* MAX_PATH_LENGTH, TR_PATH_DELIMITER */
66#include "utils.h"
67
68#define dbgmsg( ... ) \
69    do { \
70        if( tr_deepLoggingIsActive( ) ) \
71            tr_deepLog( __FILE__, __LINE__, NULL, __VA_ARGS__ ); \
72    } while( 0 )
73
74/**
75***
76**/
77
78enum
79{
80    NOFILE_BUFFER = 512, /* the process' number of open files is
81                            globalMaxPeers + NOFILE_BUFFER */
82};
83
84struct tr_openfile
85{
86    tr_bool          isWritable;
87    int              torrentId;
88    tr_file_index_t  fileNum;
89    char             filename[MAX_PATH_LENGTH];
90    int              fd;
91    uint64_t         date;
92};
93
94struct tr_fd_s
95{
96    int                   socketCount;
97    int                   socketLimit;
98    int                   openFileLimit;
99    struct tr_openfile  * openFiles;
100};
101
102static struct tr_fd_s * gFd = NULL;
103
104/***
105****
106****  Local Files
107****
108***/
109
110#ifndef O_LARGEFILE
111 #define O_LARGEFILE 0
112#endif
113
114static tr_bool
115preallocateFileSparse( int fd, uint64_t length )
116{
117    const char zero = '\0';
118
119    if( length == 0 )
120        return TRUE;
121
122    if( lseek( fd, length-1, SEEK_SET ) == -1 )
123        return FALSE;
124    if( write( fd, &zero, 1 ) == -1 )
125        return FALSE;
126    if( ftruncate( fd, length ) == -1 )
127        return FALSE;
128
129    return TRUE;
130}
131
132static tr_bool
133preallocateFileFull( const char * filename, uint64_t length )
134{
135    tr_bool success = 0;
136
137#ifdef WIN32
138
139    HANDLE hFile = CreateFile( filename, GENERIC_WRITE, 0, 0, CREATE_NEW, 0, 0 );
140    if( hFile != INVALID_HANDLE_VALUE )
141    {
142        LARGE_INTEGER li;
143        li.QuadPart = length;
144        success = SetFilePointerEx( hFile, li, NULL, FILE_BEGIN ) && SetEndOfFile( hFile );
145        CloseHandle( hFile );
146    }
147
148#else
149
150    int flags = O_RDWR | O_CREAT | O_LARGEFILE;
151    int fd = open( filename, flags, 0666 );
152    if( fd >= 0 )
153    {
154# ifdef HAVE_XFS_XFS_H
155        if( !success && platform_test_xfs_fd( fd ) )
156        {
157            xfs_flock64_t fl;
158            fl.l_whence = 0;
159            fl.l_start = 0;
160            fl.l_len = length;
161            success = !xfsctl( NULL, fd, XFS_IOC_RESVSP64, &fl );
162        }
163# endif
164# ifdef SYS_DARWIN
165        if( !success )
166        {
167            fstore_t fst;
168            fst.fst_flags = F_ALLOCATECONTIG;
169            fst.fst_posmode = F_PEOFPOSMODE;
170            fst.fst_offset = 0;
171            fst.fst_length = length;
172            fst.fst_bytesalloc = 0;
173            success = !fcntl( fd, F_PREALLOCATE, &fst );
174        }
175# endif
176# ifdef HAVE_POSIX_FALLOCATE
177        if( !success )
178        {
179            success = !posix_fallocate( fd, 0, length );
180        }
181# endif
182
183        if( !success ) /* if nothing else works, do it the old-fashioned way */
184        {
185            uint8_t buf[ 4096 ];
186            memset( buf, 0, sizeof( buf ) );
187            success = TRUE;
188            while ( success && ( length > 0 ) )
189            {
190                const int thisPass = MIN( length, sizeof( buf ) );
191                success = write( fd, buf, thisPass ) == thisPass;
192                length -= thisPass;
193            }
194        }
195
196        close( fd );
197    }
198
199#endif
200
201    return success;
202}
203
204tr_bool
205tr_preallocate_file( const char * filename, uint64_t length )
206{
207    return preallocateFileFull( filename, length );
208}
209
210int
211tr_open_file_for_writing( const char * filename )
212{
213    int flags = O_WRONLY | O_CREAT;
214#ifdef O_BINARY
215    flags |= O_BINARY;
216#endif
217#ifdef O_LARGEFILE
218    flags |= O_LARGEFILE;
219#endif
220    return open( filename, flags, 0666 );
221}
222
223int
224tr_open_file_for_scanning( const char * filename )
225{
226    int fd;
227    int flags;
228
229    /* build the flags */
230    flags = O_RDONLY;
231#ifdef O_SEQUENTIAL
232    flags |= O_SEQUENTIAL;
233#endif
234#ifdef O_BINARY
235    flags |= O_BINARY;
236#endif
237#ifdef O_LARGEFILE
238    flags |= O_LARGEFILE;
239#endif
240
241    /* open the file */
242    fd = open( filename, flags, 0666 );
243    if( fd >= 0 )
244    {
245        /* Set hints about the lookahead buffer and caching. It's okay
246           for these to fail silently, so don't let them affect errno */
247        const int err = errno;
248#ifdef HAVE_POSIX_FADVISE
249        posix_fadvise( fd, 0, 0, POSIX_FADV_SEQUENTIAL );
250#endif
251#ifdef SYS_DARWIN
252        fcntl( fd, F_NOCACHE, 1 );
253        fcntl( fd, F_RDAHEAD, 1 );
254#endif
255        errno = err;
256    }
257
258    return fd;
259}
260
261void
262tr_close_file( int fd )
263{
264#if defined(HAVE_POSIX_FADVISE)
265    /* Set hint about not caching this file.
266       It's okay for this to fail silently, so don't let it affect errno */
267    const int err = errno;
268    posix_fadvise( fd, 0, 0, POSIX_FADV_DONTNEED );
269    errno = err;
270#endif
271    close( fd );
272}
273
274/**
275 * returns 0 on success, or an errno value on failure.
276 * errno values include ENOENT if the parent folder doesn't exist,
277 * plus the errno values set by tr_mkdirp() and open().
278 */
279static int
280TrOpenFile( int                      i,
281            const char             * folder,
282            const char             * torrentFile,
283            tr_bool                  doWrite,
284            tr_preallocation_mode    preallocationMode,
285            uint64_t                 desiredFileSize )
286{
287    struct tr_openfile * file = &gFd->openFiles[i];
288    int                  flags;
289    char               * filename;
290    struct stat          sb;
291    tr_bool              alreadyExisted;
292
293    /* confirm the parent folder exists */
294    if( stat( folder, &sb ) || !S_ISDIR( sb.st_mode ) )
295    {
296        tr_err( _( "Couldn't create \"%1$s\": \"%2$s\" is not a folder" ), torrentFile, folder );
297        return ENOENT;
298    }
299
300    /* create subfolders, if any */
301    filename = tr_buildPath( folder, torrentFile, NULL );
302    if( doWrite )
303    {
304        char * tmp = tr_dirname( filename );
305        const int err = tr_mkdirp( tmp, 0777 ) ? errno : 0;
306        if( err ) {
307            tr_err( _( "Couldn't create \"%1$s\": %2$s" ), tmp, tr_strerror( err ) );
308            tr_free( tmp );
309            tr_free( filename );
310            return err;
311        }
312        tr_free( tmp );
313    }
314
315    alreadyExisted = !stat( filename, &sb ) && S_ISREG( sb.st_mode );
316
317    if( doWrite && !alreadyExisted && ( preallocationMode == TR_PREALLOCATE_FULL ) )
318        if( preallocateFileFull( filename, desiredFileSize ) )
319            tr_inf( _( "Preallocated file \"%s\"" ), filename );
320
321    /* open the file */
322    flags = doWrite ? ( O_RDWR | O_CREAT ) : O_RDONLY;
323#ifdef O_SEQUENTIAL
324    flags |= O_SEQUENTIAL;
325#endif
326#ifdef O_LARGEFILE
327    flags |= O_LARGEFILE;
328#endif
329#ifdef WIN32
330    flags |= O_BINARY;
331#endif
332    file->fd = open( filename, flags, 0666 );
333    if( file->fd == -1 )
334    {
335        const int err = errno;
336        tr_err( _( "Couldn't open \"%1$s\": %2$s" ), filename, tr_strerror( err ) );
337        tr_free( filename );
338        return err;
339    }
340
341    /* If the file already exists and it's too large, truncate it.
342     * This is a fringe case that happens if a torrent's been updated
343     * and one of the updated torrent's files is smaller.
344     * http://trac.transmissionbt.com/ticket/2228
345     * https://bugs.launchpad.net/ubuntu/+source/transmission/+bug/318249
346     */
347    if( alreadyExisted && ( desiredFileSize < (uint64_t)sb.st_size ) )
348        ftruncate( file->fd, desiredFileSize );
349
350    if( doWrite && !alreadyExisted && ( preallocationMode == TR_PREALLOCATE_SPARSE ) )
351        preallocateFileSparse( file->fd, desiredFileSize );
352
353#ifdef HAVE_POSIX_FADVISE
354    /* this doubles the OS level readahead buffer, which in practice
355     * turns out to be a good thing, because many (most?) clients request
356     * chunks of blocks in order.
357     * It's okay for this to fail silently, so don't let it affect errno */
358    {
359        const int err = errno;
360        posix_fadvise( file->fd, 0, 0, POSIX_FADV_SEQUENTIAL );
361        errno = err;
362    }
363#endif
364
365    tr_free( filename );
366    return 0;
367}
368
369static TR_INLINE tr_bool
370fileIsOpen( const struct tr_openfile * o )
371{
372    return o->fd >= 0;
373}
374
375static void
376TrCloseFile( struct tr_openfile * o )
377{
378    assert( o != NULL );
379    assert( fileIsOpen( o ) );
380
381    tr_close_file( o->fd );
382    o->fd = -1;
383}
384
385int
386tr_fdFileGetCached( int              torrentId,
387                    tr_file_index_t  fileNum,
388                    tr_bool          doWrite )
389{
390    int i;
391    struct tr_openfile * o;
392
393    assert( torrentId > 0 );
394    assert( tr_isBool( doWrite ) );
395
396    /* is it already open? */
397    for( i=0; i<gFd->openFileLimit; ++i )
398    {
399        o = &gFd->openFiles[i];
400
401        if( !fileIsOpen( o ) )
402            continue;
403        if( torrentId != o->torrentId )
404            continue;
405        if( fileNum != o->fileNum )
406            continue;
407
408        break;
409    }
410
411    if( ( o != NULL ) && ( !doWrite || o->isWritable ) )
412    {
413        o->date = tr_date( );
414        return o->fd;
415    }
416
417    return -1;
418}
419
420/* returns an fd on success, or a -1 on failure and sets errno */
421int
422tr_fdFileCheckout( int                      torrentId,
423                   tr_file_index_t          fileNum,
424                   const char             * folder,
425                   const char             * torrentFile,
426                   tr_bool                  doWrite,
427                   tr_preallocation_mode    preallocationMode,
428                   uint64_t                 desiredFileSize )
429{
430    int i, winner = -1;
431    struct tr_openfile * o;
432    char filename[MAX_PATH_LENGTH];
433
434    assert( torrentId > 0 );
435    assert( folder && *folder );
436    assert( torrentFile && *torrentFile );
437    assert( tr_isBool( doWrite ) );
438
439    tr_snprintf( filename, sizeof( filename ), "%s%c%s", folder, TR_PATH_DELIMITER, torrentFile );
440    dbgmsg( "looking for file '%s', writable %c", filename, doWrite ? 'y' : 'n' );
441
442    /* is it already open? */
443    for( i=0; i<gFd->openFileLimit; ++i )
444    {
445        o = &gFd->openFiles[i];
446
447        if( !fileIsOpen( o ) )
448            continue;
449        if( torrentId != o->torrentId )
450            continue;
451        if( fileNum != o->fileNum )
452            continue;
453
454        if( doWrite && !o->isWritable )
455        {
456            dbgmsg( "found it!  it's open and available, but isn't writable. closing..." );
457            TrCloseFile( o );
458            break;
459        }
460
461        dbgmsg( "found it!  it's ready for use!" );
462        winner = i;
463        break;
464    }
465
466    dbgmsg( "it's not already open.  looking for an open slot or an old file." );
467    while( winner < 0 )
468    {
469        uint64_t date = tr_date( ) + 1;
470
471        /* look for the file that's been open longest */
472        for( i=0; i<gFd->openFileLimit; ++i )
473        {
474            o = &gFd->openFiles[i];
475
476            if( !fileIsOpen( o ) )
477            {
478                winner = i;
479                dbgmsg( "found an empty slot in %d", winner );
480                break;
481            }
482
483            if( date > o->date )
484            {
485                date = o->date;
486                winner = i;
487            }
488        }
489
490        assert( winner >= 0 );
491
492        if( fileIsOpen( &gFd->openFiles[winner] ) )
493        {
494            dbgmsg( "closing file \"%s\"", gFd->openFiles[winner].filename );
495            TrCloseFile( &gFd->openFiles[winner] );
496        }
497    }
498
499    assert( winner >= 0 );
500    o = &gFd->openFiles[winner];
501    if( !fileIsOpen( o ) )
502    {
503        const int err = TrOpenFile( winner, folder, torrentFile, doWrite,
504                                    preallocationMode, desiredFileSize );
505        if( err ) {
506            errno = err;
507            return -1;
508        }
509
510        dbgmsg( "opened '%s' in slot %d, doWrite %c", filename, winner,
511                doWrite ? 'y' : 'n' );
512        tr_strlcpy( o->filename, filename, sizeof( o->filename ) );
513        o->isWritable = doWrite;
514    }
515
516    dbgmsg( "checking out '%s' in slot %d", filename, winner );
517    o->torrentId = torrentId;
518    o->fileNum = fileNum;
519    o->date = tr_date( );
520    return o->fd;
521}
522
523void
524tr_fdFileClose( const tr_torrent * tor, tr_file_index_t fileNum )
525{
526    struct tr_openfile * o;
527    const struct tr_openfile * end;
528    const int torrentId = tr_torrentId( tor );
529    for( o=gFd->openFiles, end=o+gFd->openFileLimit; o!=end; ++o )
530    {
531        if( !fileIsOpen( o ) )
532            continue;
533        if( torrentId != o->torrentId )
534            continue;
535        if( fileNum != o->fileNum )
536            continue;
537
538        dbgmsg( "tr_fdFileClose closing \"%s\"", o->filename );
539        TrCloseFile( o );
540    }
541}
542
543void
544tr_fdTorrentClose( int torrentId )
545{
546    struct tr_openfile * o;
547    const struct tr_openfile * end;
548
549    for( o=gFd->openFiles, end=o+gFd->openFileLimit; o!=end; ++o )
550        if( fileIsOpen( o ) && o->torrentId == torrentId )
551            TrCloseFile( o );
552}
553
554/***
555****
556****  Sockets
557****
558***/
559
560static TR_INLINE int
561getSocketMax( struct tr_fd_s * gFd )
562{
563    return gFd->socketLimit;
564}
565
566int
567tr_fdSocketCreate( int domain, int type )
568{
569    int s = -1;
570
571    if( gFd->socketCount < getSocketMax( gFd ) )
572        if( ( s = socket( domain, type, 0 ) ) < 0 )
573        {
574            if( sockerrno != EAFNOSUPPORT )
575                tr_err( _( "Couldn't create socket: %s" ),
576                        tr_strerror( sockerrno ) );
577        }
578
579    if( s > -1 )
580        ++gFd->socketCount;
581
582    assert( gFd->socketCount >= 0 );
583
584    return s;
585}
586
587int
588tr_fdSocketAccept( int           b,
589                   tr_address  * addr,
590                   tr_port     * port )
591{
592    int s;
593    unsigned int len;
594    struct sockaddr_storage sock;
595
596    assert( addr );
597    assert( port );
598
599    len = sizeof( struct sockaddr_storage );
600    s = accept( b, (struct sockaddr *) &sock, &len );
601
602    if( ( s >= 0 ) && gFd->socketCount > getSocketMax( gFd ) )
603    {
604        EVUTIL_CLOSESOCKET( s );
605        s = -1;
606    }
607
608    if( s >= 0 )
609    {
610        /* "The ss_family field of the sockaddr_storage structure will always
611         * align with the family field of any protocol-specific structure." */
612        if( sock.ss_family == AF_INET )
613        {
614            struct sockaddr_in *si;
615            union { struct sockaddr_storage dummy; struct sockaddr_in si; } s;
616            s.dummy = sock;
617            si = &s.si;
618            addr->type = TR_AF_INET;
619            addr->addr.addr4.s_addr = si->sin_addr.s_addr;
620            *port = si->sin_port;
621        }
622        else
623        {
624            struct sockaddr_in6 *si;
625            union { struct sockaddr_storage dummy; struct sockaddr_in6 si; } s;
626            s.dummy = sock;
627            si = &s.si;
628            addr->type = TR_AF_INET6;
629            addr->addr.addr6 = si->sin6_addr;
630            *port = si->sin6_port;
631        }
632        ++gFd->socketCount;
633    }
634
635    return s;
636}
637
638void
639tr_fdSocketClose( int fd )
640{
641    if( fd >= 0 )
642    {
643        EVUTIL_CLOSESOCKET( fd );
644        --gFd->socketCount;
645    }
646
647    assert( gFd->socketCount >= 0 );
648}
649
650/***
651****
652****  Startup / Shutdown
653****
654***/
655
656void
657tr_fdInit( size_t openFileLimit, size_t socketLimit )
658{
659    int i;
660
661    assert( gFd == NULL );
662    gFd = tr_new0( struct tr_fd_s, 1 );
663    gFd->openFiles = tr_new0( struct tr_openfile, openFileLimit );
664    gFd->openFileLimit = openFileLimit;
665
666#ifdef HAVE_GETRLIMIT
667    {
668        struct rlimit rlim;
669        getrlimit( RLIMIT_NOFILE, &rlim );
670        rlim.rlim_cur = MIN( rlim.rlim_max,
671                            (rlim_t)( socketLimit + NOFILE_BUFFER ) );
672        setrlimit( RLIMIT_NOFILE, &rlim );
673        gFd->socketLimit = rlim.rlim_cur - NOFILE_BUFFER;
674        tr_dbg( "setrlimit( RLIMIT_NOFILE, %d )", (int)rlim.rlim_cur );
675    }
676#else
677    gFd->socketLimit = socketLimit;
678#endif
679    tr_dbg( "%zu usable file descriptors", socketLimit );
680
681    for( i = 0; i < gFd->openFileLimit; ++i )
682        gFd->openFiles[i].fd = -1;
683}
684
685void
686tr_fdClose( void )
687{
688    struct tr_openfile * o;
689    const struct tr_openfile * end;
690
691    for( o=gFd->openFiles, end=o+gFd->openFileLimit; o!=end; ++o )
692        if( fileIsOpen( o ) )
693            TrCloseFile( o );
694
695    tr_free( gFd->openFiles );
696    tr_free( gFd );
697    gFd = NULL;
698}
699
700void
701tr_fdSetPeerLimit( uint16_t n )
702{
703    assert( gFd != NULL && "tr_fdInit() must be called first!" );
704    gFd->socketLimit = n;
705}
706
707uint16_t
708tr_fdGetPeerLimit( void )
709{
710    return gFd ? gFd->socketLimit : -1;
711}
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