source: trunk/libtransmission/fdlimit.c @ 8780

Last change on this file since 8780 was 8780, checked in by charles, 12 years ago

(trunk libT) remove dead code

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1/******************************************************************************
2 * $Id: fdlimit.c 8780 2009-07-04 04:33:23Z 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    isCheckedOut;
87    tr_bool    isWritable;
88    int        torrentId;
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    posix_fadvise( file->fd, 0, 0, POSIX_FADV_SEQUENTIAL );
358#endif
359
360    tr_free( filename );
361    return 0;
362}
363
364static TR_INLINE tr_bool
365fileIsOpen( const struct tr_openfile * o )
366{
367    return o->fd >= 0;
368}
369
370static void
371TrCloseFile( struct tr_openfile * o )
372{
373    assert( o != NULL );
374    assert( fileIsOpen( o ) );
375
376    tr_close_file( o->fd );
377    o->fd = -1;
378    o->isCheckedOut = FALSE;
379}
380
381static int
382fileIsCheckedOut( const struct tr_openfile * o )
383{
384    return fileIsOpen( o ) && o->isCheckedOut;
385}
386
387/* returns an fd on success, or a -1 on failure and sets errno */
388int
389tr_fdFileCheckout( int                      torrentId,
390                   const char             * folder,
391                   const char             * torrentFile,
392                   tr_bool                  doWrite,
393                   tr_preallocation_mode    preallocationMode,
394                   uint64_t                 desiredFileSize )
395{
396    int i, winner = -1;
397    struct tr_openfile * o;
398    char filename[MAX_PATH_LENGTH];
399
400    assert( torrentId > 0 );
401    assert( folder && *folder );
402    assert( torrentFile && *torrentFile );
403    assert( tr_isBool( doWrite ) );
404
405    tr_snprintf( filename, sizeof( filename ), "%s%c%s", folder, TR_PATH_DELIMITER, torrentFile );
406    dbgmsg( "looking for file '%s', writable %c", filename, doWrite ? 'y' : 'n' );
407
408    /* is it already open? */
409    for( i=0; i<gFd->openFileLimit; ++i )
410    {
411        o = &gFd->openFiles[i];
412
413        if( !fileIsOpen( o ) )
414            continue;
415        if( torrentId != o->torrentId )
416            continue;
417        if( strcmp( filename, o->filename ) )
418            continue;
419
420        assert( !fileIsCheckedOut( o ) );
421
422        if( doWrite && !o->isWritable )
423        {
424            dbgmsg( "found it!  it's open and available, but isn't writable. closing..." );
425            TrCloseFile( o );
426            break;
427        }
428
429        dbgmsg( "found it!  it's ready for use!" );
430        winner = i;
431        break;
432    }
433
434    dbgmsg( "it's not already open.  looking for an open slot or an old file." );
435    while( winner < 0 )
436    {
437        uint64_t date = tr_date( ) + 1;
438
439        /* look for the file that's been open longest */
440        for( i=0; i<gFd->openFileLimit; ++i )
441        {
442            o = &gFd->openFiles[i];
443
444            if( !fileIsOpen( o ) )
445            {
446                winner = i;
447                dbgmsg( "found an empty slot in %d", winner );
448                break;
449            }
450
451            if( date > o->date )
452            {
453                date = o->date;
454                winner = i;
455            }
456        }
457
458        assert( winner >= 0 );
459       
460        if( fileIsOpen( &gFd->openFiles[winner] ) )
461        {
462            dbgmsg( "closing file \"%s\"", gFd->openFiles[winner].filename );
463            TrCloseFile( &gFd->openFiles[winner] );
464        }
465    }
466
467    assert( winner >= 0 );
468    o = &gFd->openFiles[winner];
469    if( !fileIsOpen( o ) )
470    {
471        const int err = TrOpenFile( winner, folder, torrentFile, doWrite,
472                                    preallocationMode, desiredFileSize );
473        if( err ) {
474            errno = err;
475            return -1;
476        }
477
478        dbgmsg( "opened '%s' in slot %d, doWrite %c", filename, winner,
479                doWrite ? 'y' : 'n' );
480        tr_strlcpy( o->filename, filename, sizeof( o->filename ) );
481        o->isWritable = doWrite;
482    }
483
484    dbgmsg( "checking out '%s' in slot %d", filename, winner );
485    o->torrentId = torrentId;
486    o->isCheckedOut = 1;
487    o->date = tr_date( );
488    return o->fd;
489}
490
491void
492tr_fdFileReturn( int fd )
493{
494    struct tr_openfile * o;
495    const struct tr_openfile * end;
496
497    for( o=gFd->openFiles, end=o+gFd->openFileLimit; o!=end; ++o )
498    {
499        if( o->fd != fd )
500            continue;
501        dbgmsg( "releasing file \"%s\"", o->filename );
502        o->isCheckedOut = FALSE;
503        break;
504    }
505}
506
507void
508tr_fdFileClose( const char * filename )
509{
510    struct tr_openfile * o;
511    const struct tr_openfile * end;
512
513    for( o=gFd->openFiles, end=o+gFd->openFileLimit; o!=end; ++o )
514    {
515        if( !fileIsOpen( o ) || strcmp( filename, o->filename ) )
516            continue;
517        dbgmsg( "tr_fdFileClose closing \"%s\"", filename );
518        assert( !o->isCheckedOut && "this is a test assertion... I *think* this is always true now" );
519        TrCloseFile( o );
520    }
521}
522
523void
524tr_fdTorrentClose( int torrentId )
525{
526    struct tr_openfile * o;
527    const struct tr_openfile * end;
528
529    for( o=gFd->openFiles, end=o+gFd->openFileLimit; o!=end; ++o )
530        if( fileIsOpen( o ) && o->torrentId == torrentId )
531            TrCloseFile( o );
532}
533
534/***
535****
536****  Sockets
537****
538***/
539
540static TR_INLINE int
541getSocketMax( struct tr_fd_s * gFd )
542{
543    return gFd->socketLimit;
544}
545
546int
547tr_fdSocketCreate( int domain, int type )
548{
549    int s = -1;
550
551    if( gFd->socketCount < getSocketMax( gFd ) )
552        if( ( s = socket( domain, type, 0 ) ) < 0 )
553        {
554#ifdef SYS_DARWIN
555            if( sockerrno != EAFNOSUPPORT )
556#endif
557            tr_err( _( "Couldn't create socket: %s" ),
558                   tr_strerror( sockerrno ) );
559            s = -sockerrno;
560        }
561
562    if( s > -1 )
563        ++gFd->socketCount;
564
565    assert( gFd->socketCount >= 0 );
566
567    return s;
568}
569
570int
571tr_fdSocketAccept( int           b,
572                   tr_address  * addr,
573                   tr_port     * port )
574{
575    int s;
576    unsigned int len;
577    struct sockaddr_storage sock;
578
579    assert( addr );
580    assert( port );
581
582    len = sizeof( struct sockaddr_storage );
583    s = accept( b, (struct sockaddr *) &sock, &len );
584
585    if( ( s >= 0 ) && gFd->socketCount > getSocketMax( gFd ) )
586    {
587        EVUTIL_CLOSESOCKET( s );
588        s = -1;
589    }
590
591    if( s >= 0 )
592    {
593        /* "The ss_family field of the sockaddr_storage structure will always
594         * align with the family field of any protocol-specific structure." */ 
595        if( sock.ss_family == AF_INET ) 
596        {
597            struct sockaddr_in *si;
598            union { struct sockaddr_storage dummy; struct sockaddr_in si; } s;
599            s.dummy = sock;
600            si = &s.si;
601            addr->type = TR_AF_INET; 
602            addr->addr.addr4.s_addr = si->sin_addr.s_addr; 
603            *port = si->sin_port; 
604        } 
605        else 
606        { 
607            struct sockaddr_in6 *si;
608            union { struct sockaddr_storage dummy; struct sockaddr_in6 si; } s;
609            s.dummy = sock;
610            si = &s.si;
611            addr->type = TR_AF_INET6; 
612            addr->addr.addr6 = si->sin6_addr;
613            *port = si->sin6_port; 
614        } 
615        ++gFd->socketCount;
616    }
617
618    return s;
619}
620
621void
622tr_fdSocketClose( int fd )
623{
624    if( fd >= 0 )
625    {
626        EVUTIL_CLOSESOCKET( fd );
627        --gFd->socketCount;
628    }
629
630    assert( gFd->socketCount >= 0 );
631}
632
633/***
634****
635****  Startup / Shutdown
636****
637***/
638
639void
640tr_fdInit( size_t openFileLimit, size_t socketLimit )
641{
642    int i;
643
644    assert( gFd == NULL );
645    gFd = tr_new0( struct tr_fd_s, 1 );
646    gFd->openFiles = tr_new0( struct tr_openfile, openFileLimit );
647    gFd->openFileLimit = openFileLimit;
648
649#ifdef HAVE_GETRLIMIT
650    {
651        struct rlimit rlim;
652        getrlimit( RLIMIT_NOFILE, &rlim );
653        rlim.rlim_cur = MIN( rlim.rlim_max,
654                            (rlim_t)( socketLimit + NOFILE_BUFFER ) );
655        setrlimit( RLIMIT_NOFILE, &rlim );
656        gFd->socketLimit = rlim.rlim_cur - NOFILE_BUFFER;
657        tr_dbg( "setrlimit( RLIMIT_NOFILE, %d )", (int)rlim.rlim_cur );
658    }
659#else
660    gFd->socketLimit = socketLimit;
661#endif
662    tr_dbg( "%zu usable file descriptors", socketLimit );
663
664    for( i = 0; i < gFd->openFileLimit; ++i )
665        gFd->openFiles[i].fd = -1;
666}
667
668void
669tr_fdClose( void )
670{
671    struct tr_openfile * o;
672    const struct tr_openfile * end;
673
674    for( o=gFd->openFiles, end=o+gFd->openFileLimit; o!=end; ++o )
675        if( fileIsOpen( o ) )
676            TrCloseFile( o );
677
678    tr_free( gFd->openFiles );
679    tr_free( gFd );
680    gFd = NULL;
681}
682
683void
684tr_fdSetPeerLimit( uint16_t n )
685{
686    assert( gFd != NULL && "tr_fdInit() must be called first!" );
687    gFd->socketLimit = n;
688}
689
690uint16_t
691tr_fdGetPeerLimit( void )
692{
693    return gFd ? gFd->socketLimit : -1;
694}
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