source: trunk/libtransmission/fdlimit.c @ 8349

Last change on this file since 8349 was 8349, checked in by charles, 13 years ago

(trunk libT) do for tr_close_file() what r8348 did for tr_open_file_for_scanning()

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1/******************************************************************************
2 * $Id: fdlimit.c 8349 2009-05-07 11:54:09Z 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_FALLOCATE
47 #include <linux/falloc.h>
48#endif
49
50#ifdef HAVE_XFS_XFS_H
51 #include <xfs/xfs.h>
52#endif
53
54#include <sys/types.h>
55#include <sys/stat.h>
56#ifdef HAVE_GETRLIMIT
57 #include <sys/time.h> /* getrlimit */
58 #include <sys/resource.h> /* getrlimit */
59#endif
60#include <unistd.h>
61#include <fcntl.h> /* O_LARGEFILE posix_fadvise */
62
63#include <evutil.h>
64
65#include "transmission.h"
66#include "fdlimit.h"
67#include "list.h"
68#include "net.h"
69#include "platform.h" /* tr_lock */
70#include "utils.h"
71
72#define dbgmsg( ... ) \
73    do { \
74        if( tr_deepLoggingIsActive( ) ) \
75            tr_deepLog( __FILE__, __LINE__, NULL, __VA_ARGS__ ); \
76    } while( 0 )
77
78/**
79***
80**/
81
82enum
83{
84    NOFILE_BUFFER = 512, /* the process' number of open files is
85                            globalMaxPeers + NOFILE_BUFFER */
86};
87
88struct tr_openfile
89{
90    tr_bool    isCheckedOut;
91    tr_bool    isWritable;
92    tr_bool    closeWhenDone;
93    char       filename[MAX_PATH_LENGTH];
94    int        fd;
95    uint64_t   date;
96};
97
98struct tr_fd_s
99{
100    int                   socketCount;
101    int                   socketLimit;
102
103    struct tr_openfile  * openFiles;
104    int                   openFileLimit;
105
106    tr_lock             * lock;
107};
108
109static struct tr_fd_s * gFd = NULL;
110
111/***
112****
113****  Local Files
114****
115***/
116
117#ifndef O_LARGEFILE
118 #define O_LARGEFILE 0
119#endif
120
121static tr_bool
122preallocateFileSparse( int fd, uint64_t length )
123{
124    const char zero = '\0';
125
126    if( length == 0 )
127        return TRUE;
128
129    if( lseek( fd, length-1, SEEK_SET ) == -1 )
130        return FALSE;
131    if( write( fd, &zero, 1 ) == -1 )
132        return FALSE;
133    if( ftruncate( fd, length ) == -1 )
134        return FALSE;
135
136    return TRUE;
137}
138
139static tr_bool
140preallocateFileFull( const char * filename, uint64_t length )
141{
142    tr_bool success = 0;
143
144#ifdef WIN32
145
146    HANDLE hFile = CreateFile( filename, GENERIC_WRITE, 0, 0, CREATE_NEW, 0, 0 );
147    if( hFile != INVALID_HANDLE_VALUE )
148    {
149        LARGE_INTEGER li;
150        li.QuadPart = length;
151        success = SetFilePointerEx( hFile, li, NULL, FILE_BEGIN ) && SetEndOfFile( hFile );
152        CloseHandle( hFile );
153    }
154
155#else
156
157    int flags = O_RDWR | O_CREAT | O_LARGEFILE;
158    int fd = open( filename, flags, 0666 );
159    if( fd >= 0 )
160    {
161# ifdef HAVE_XFS_XFS_H
162        if( !success && platform_test_xfs_fd( fd ) )
163        {
164            xfs_flock64_t fl;
165            fl.l_whence = 0;
166            fl.l_start = 0;
167            fl.l_len = length;
168            success = !xfsctl( NULL, fd, XFS_IOC_RESVSP64, &fl );
169        }
170# endif
171# ifdef SYS_DARWIN
172        if( !success )
173        {
174            fstore_t fst;
175            fst.fst_flags = F_ALLOCATECONTIG;
176            fst.fst_posmode = F_PEOFPOSMODE;
177            fst.fst_offset = 0;
178            fst.fst_length = length;
179            fst.fst_bytesalloc = 0;
180            success = !fcntl( fd, F_PREALLOCATE, &fst );
181        }
182# endif
183# ifdef HAVE_FALLOCATE
184        if( !success )
185        {
186            success = !fallocate( fd, FALLOC_FL_KEEP_SIZE, 0, length );
187        }
188# endif
189# ifdef HAVE_POSIX_FALLOCATE
190        if( !success )
191        {
192            success = !posix_fallocate( fd, 0, length );
193        }
194# endif
195
196        close( fd );
197    }
198
199#endif
200
201    return success;
202}
203
204int
205tr_open_file_for_scanning( const char * filename )
206{
207    int fd;
208    int flags;
209
210    /* build the flags */
211    flags = O_RDONLY;
212#ifdef O_SEQUENTIAL
213    flags |= O_SEQUENTIAL;
214#endif
215#ifdef O_BINARY
216    flags |= O_BINARY;
217#endif
218#ifdef O_LARGEFILE
219    flags |= O_LARGEFILE;
220#endif
221
222    /* open the file */
223    fd = open( filename, flags, 0666 );
224    if( fd >= 0 )
225    {
226        /* Set hints about the lookahead buffer and caching. It's okay
227           for these to fail silently, so don't let them affect errno */
228        const int err = errno;
229#ifdef HAVE_POSIX_FADVISE
230        posix_fadvise( fd, 0, 0, POSIX_FADV_SEQUENTIAL );
231#endif
232#ifdef SYS_DARWIN
233        fcntl( fd, F_NOCACHE, 1 );
234        fcntl( fd, F_RDAHEAD, 1 );
235#endif
236        errno = err;
237    }
238
239    return fd;
240}
241
242void
243tr_close_file( int fd )
244{
245#if defined(HAVE_POSIX_FADVISE)
246    const int err = errno;
247    /* Set hint about not caching this file.
248       It's okay for this to fail silently, so don't let it affect errno */
249    posix_fadvise( fd, 0, 0, POSIX_FADV_DONTNEED );
250    errno = err;
251#endif
252    close( fd );
253}
254
255/**
256 * returns 0 on success, or an errno value on failure.
257 * errno values include ENOENT if the parent folder doesn't exist,
258 * plus the errno values set by tr_mkdirp() and open().
259 */
260static int
261TrOpenFile( int                      i,
262            const char             * folder,
263            const char             * torrentFile,
264            tr_bool                  doWrite,
265            tr_preallocation_mode    preallocationMode,
266            uint64_t                 desiredFileSize )
267{
268    struct tr_openfile * file = &gFd->openFiles[i];
269    int                  flags;
270    char               * filename;
271    struct stat          sb;
272    int                  alreadyExisted;
273
274    /* confirm the parent folder exists */
275    if( stat( folder, &sb ) || !S_ISDIR( sb.st_mode ) )
276    {
277        tr_err( _( "Couldn't create \"%1$s\": parent folder \"%2$s\" does not exist" ), torrentFile, folder );
278        return ENOENT;
279    }
280
281    /* create subfolders, if any */
282    filename = tr_buildPath( folder, torrentFile, NULL );
283    if( doWrite )
284    {
285        char * tmp = tr_dirname( filename );
286        const int err = tr_mkdirp( tmp, 0777 ) ? errno : 0;
287        if( err ) {
288            tr_err( _( "Couldn't create \"%1$s\": %2$s" ), tmp, tr_strerror( err ) );
289            tr_free( tmp );
290            tr_free( filename );
291            return err;
292        }
293        tr_free( tmp );
294    }
295
296    alreadyExisted = !stat( filename, &sb ) && S_ISREG( sb.st_mode );
297
298    if( doWrite && !alreadyExisted && ( preallocationMode == TR_PREALLOCATE_FULL ) )
299        if( preallocateFileFull( filename, desiredFileSize ) )
300            tr_inf( _( "Preallocated file \"%s\"" ), filename );
301   
302    /* open the file */
303    flags = doWrite ? ( O_RDWR | O_CREAT ) : O_RDONLY;
304#ifdef O_RANDOM
305    flags |= O_RANDOM
306#endif
307#ifdef O_LARGEFILE
308    flags |= O_LARGEFILE;
309#endif
310#ifdef WIN32
311    flags |= O_BINARY;
312#endif
313    file->fd = open( filename, flags, 0666 );
314    if( file->fd == -1 )
315    {
316        const int err = errno;
317        tr_err( _( "Couldn't open \"%1$s\": %2$s" ), filename, tr_strerror( err ) );
318        tr_free( filename );
319        return err;
320    }
321
322    if( doWrite && !alreadyExisted && ( preallocationMode == TR_PREALLOCATE_SPARSE ) )
323        preallocateFileSparse( file->fd, desiredFileSize );
324
325#ifdef HAVE_POSIX_FADVISE
326    posix_fadvise( file->fd, 0, 0, POSIX_FADV_RANDOM );
327#endif
328
329    tr_free( filename );
330    return 0;
331}
332
333static int
334fileIsOpen( const struct tr_openfile * o )
335{
336    return o->fd >= 0;
337}
338
339static void
340TrCloseFile( int i )
341{
342    struct tr_openfile * o = &gFd->openFiles[i];
343
344    assert( i >= 0 );
345    assert( i < gFd->openFileLimit );
346    assert( fileIsOpen( o ) );
347
348    tr_close_file( o->fd );
349    o->fd = -1;
350    o->isCheckedOut = 0;
351}
352
353static int
354fileIsCheckedOut( const struct tr_openfile * o )
355{
356    return fileIsOpen( o ) && o->isCheckedOut;
357}
358
359/* returns an fd on success, or a -1 on failure and sets errno */
360int
361tr_fdFileCheckout( const char             * folder,
362                   const char             * torrentFile,
363                   tr_bool                  doWrite,
364                   tr_preallocation_mode    preallocationMode,
365                   uint64_t                 desiredFileSize )
366{
367    int i, winner = -1;
368    struct tr_openfile * o;
369    char filename[MAX_PATH_LENGTH];
370
371    assert( folder && *folder );
372    assert( torrentFile && *torrentFile );
373    assert( doWrite == 0 || doWrite == 1 );
374
375    tr_snprintf( filename, sizeof( filename ), "%s%c%s", folder, TR_PATH_DELIMITER, torrentFile );
376    dbgmsg( "looking for file '%s', writable %c", filename, doWrite ? 'y' : 'n' );
377
378    tr_lockLock( gFd->lock );
379
380    /* Is it already open? */
381    for( i = 0; i < gFd->openFileLimit; ++i )
382    {
383        o = &gFd->openFiles[i];
384
385        if( !fileIsOpen( o ) )
386            continue;
387
388        if( strcmp( filename, o->filename ) )
389            continue;
390
391        if( fileIsCheckedOut( o ) )
392        {
393            dbgmsg( "found it!  it's open, but checked out.  waiting..." );
394            tr_lockUnlock( gFd->lock );
395            tr_wait( 200 );
396            tr_lockLock( gFd->lock );
397            i = -1; /* reloop */
398            continue;
399        }
400
401        if( doWrite && !o->isWritable )
402        {
403            dbgmsg(
404                "found it!  it's open and available, but isn't writable. closing..." );
405            TrCloseFile( i );
406            break;
407        }
408
409        dbgmsg( "found it!  it's ready for use!" );
410        winner = i;
411        break;
412    }
413
414    dbgmsg(
415        "it's not already open.  looking for an open slot or an old file." );
416    while( winner < 0 )
417    {
418        uint64_t date = tr_date( ) + 1;
419
420        /* look for the file that's been open longest */
421        for( i = 0; i < gFd->openFileLimit; ++i )
422        {
423            o = &gFd->openFiles[i];
424
425            if( !fileIsOpen( o ) )
426            {
427                winner = i;
428                dbgmsg( "found an empty slot in %d", winner );
429                break;
430            }
431
432            if( date > o->date )
433            {
434                date = o->date;
435                winner = i;
436            }
437        }
438
439        if( winner >= 0 )
440        {
441            if( fileIsOpen( &gFd->openFiles[winner] ) )
442            {
443                dbgmsg( "closing file '%s', slot #%d",
444                        gFd->openFiles[winner].filename,
445                        winner );
446                TrCloseFile( winner );
447            }
448        }
449        else
450        {
451            dbgmsg( "everything's full!  waiting for someone else to finish something" );
452            tr_lockUnlock( gFd->lock );
453            tr_wait( 200 );
454            tr_lockLock( gFd->lock );
455        }
456    }
457
458    assert( winner >= 0 );
459    o = &gFd->openFiles[winner];
460    if( !fileIsOpen( o ) )
461    {
462        const int err = TrOpenFile( winner, folder, torrentFile, doWrite, preallocationMode, desiredFileSize );
463        if( err ) {
464            tr_lockUnlock( gFd->lock );
465            errno = err;
466            return -1;
467        }
468
469        dbgmsg( "opened '%s' in slot %d, doWrite %c", filename, winner,
470                doWrite ? 'y' : 'n' );
471        tr_strlcpy( o->filename, filename, sizeof( o->filename ) );
472        o->isWritable = doWrite;
473    }
474
475    dbgmsg( "checking out '%s' in slot %d", filename, winner );
476    o->isCheckedOut = 1;
477    o->closeWhenDone = 0;
478    o->date = tr_date( );
479    tr_lockUnlock( gFd->lock );
480    return o->fd;
481}
482
483void
484tr_fdFileReturn( int fd )
485{
486    int i;
487
488    tr_lockLock( gFd->lock );
489
490    for( i = 0; i < gFd->openFileLimit; ++i )
491    {
492        struct tr_openfile * o = &gFd->openFiles[i];
493        if( o->fd != fd )
494            continue;
495
496        dbgmsg( "releasing file '%s' in slot #%d", o->filename, i );
497        o->isCheckedOut = 0;
498        if( o->closeWhenDone )
499            TrCloseFile( i );
500
501        break;
502    }
503
504    tr_lockUnlock( gFd->lock );
505}
506
507void
508tr_fdFileClose( const char * filename )
509{
510    int i;
511
512    tr_lockLock( gFd->lock );
513
514    for( i = 0; i < gFd->openFileLimit; ++i )
515    {
516        struct tr_openfile * o = &gFd->openFiles[i];
517        if( !fileIsOpen( o ) || strcmp( filename, o->filename ) )
518            continue;
519
520        dbgmsg( "tr_fdFileClose closing '%s'", filename );
521
522        if( !o->isCheckedOut )
523        {
524            dbgmsg( "not checked out, so closing it now... '%s'", filename );
525            TrCloseFile( i );
526        }
527        else
528        {
529            dbgmsg(
530                "flagging file '%s', slot #%d to be closed when checked in",
531                gFd->openFiles[i].filename, i );
532            o->closeWhenDone = 1;
533        }
534    }
535
536    tr_lockUnlock( gFd->lock );
537}
538
539/***
540****
541****  Sockets
542****
543***/
544
545static int
546getSocketMax( struct tr_fd_s * gFd )
547{
548    return gFd->socketLimit;
549}
550
551int
552tr_fdSocketCreate( int domain, int type )
553{
554    int s = -1;
555
556    tr_lockLock( gFd->lock );
557
558    if( gFd->socketCount < getSocketMax( gFd ) )
559        if( ( s = socket( domain, type, 0 ) ) < 0 )
560        {
561#ifdef SYS_DARWIN
562            if( sockerrno != EAFNOSUPPORT )
563#endif
564            tr_err( _( "Couldn't create socket: %s" ),
565                   tr_strerror( sockerrno ) );
566            s = -sockerrno;
567        }
568
569    if( s > -1 )
570        ++gFd->socketCount;
571
572    assert( gFd->socketCount >= 0 );
573
574    tr_lockUnlock( gFd->lock );
575    return s;
576}
577
578int
579tr_fdSocketAccept( int           b,
580                   tr_address  * addr,
581                   tr_port     * port )
582{
583    int                s = -1;
584    unsigned int       len;
585    struct sockaddr_storage sock;
586
587    assert( addr );
588    assert( port );
589
590    tr_lockLock( gFd->lock );
591    if( gFd->socketCount < getSocketMax( gFd ) )
592    {
593        len = sizeof( struct sockaddr_storage );
594        s = accept( b, (struct sockaddr *) &sock, &len );
595    }
596    if( s > -1 )
597    {
598        /* "The ss_family field of the sockaddr_storage structure will always
599         * align with the family field of any protocol-specific structure." */ 
600        if( sock.ss_family == AF_INET ) 
601        { 
602            struct sockaddr_in * sock4 = (struct sockaddr_in *)&sock; 
603            addr->type = TR_AF_INET; 
604            addr->addr.addr4.s_addr = sock4->sin_addr.s_addr; 
605            *port = sock4->sin_port; 
606        } 
607        else 
608        { 
609            struct sockaddr_in6 * sock6 = (struct sockaddr_in6 *)&sock; 
610            addr->type = TR_AF_INET6; 
611            addr->addr.addr6 = sock6->sin6_addr;
612            *port = sock6->sin6_port; 
613        } 
614        ++gFd->socketCount;
615    }
616    tr_lockUnlock( gFd->lock );
617
618    return s;
619}
620
621static void
622socketClose( int fd )
623{
624    EVUTIL_CLOSESOCKET( fd );
625}
626
627void
628tr_fdSocketClose( int s )
629{
630    tr_lockLock( gFd->lock );
631
632    if( s >= 0 )
633    {
634        socketClose( s );
635        --gFd->socketCount;
636    }
637
638    assert( gFd->socketCount >= 0 );
639
640    tr_lockUnlock( gFd->lock );
641}
642
643/***
644****
645****  Startup / Shutdown
646****
647***/
648
649void
650tr_fdInit( size_t openFileLimit, size_t socketLimit )
651{
652    int i;
653
654    assert( gFd == NULL );
655    gFd = tr_new0( struct tr_fd_s, 1 );
656    gFd->openFiles = tr_new0( struct tr_openfile, openFileLimit );
657    gFd->openFileLimit = openFileLimit;
658    gFd->lock = tr_lockNew( );
659
660#ifdef HAVE_GETRLIMIT
661    {
662        struct rlimit rlim;
663        getrlimit( RLIMIT_NOFILE, &rlim );
664        rlim.rlim_cur = MIN( rlim.rlim_max,
665                            (rlim_t)( socketLimit + NOFILE_BUFFER ) );
666        setrlimit( RLIMIT_NOFILE, &rlim );
667        gFd->socketLimit = rlim.rlim_cur - NOFILE_BUFFER;
668        tr_dbg( "setrlimit( RLIMIT_NOFILE, %d )", (int)rlim.rlim_cur );
669    }
670#else
671    gFd->socketLimit = socketLimit;
672#endif
673    tr_dbg( "%zu usable file descriptors", socketLimit );
674
675    for( i = 0; i < gFd->openFileLimit; ++i )
676        gFd->openFiles[i].fd = -1;
677}
678
679void
680tr_fdClose( void )
681{
682    int i = 0;
683
684    for( i = 0; i < gFd->openFileLimit; ++i )
685        if( fileIsOpen( &gFd->openFiles[i] ) )
686            TrCloseFile( i );
687
688    tr_lockFree( gFd->lock );
689
690    tr_free( gFd->openFiles );
691    tr_free( gFd );
692    gFd = NULL;
693}
694
695void
696tr_fdSetPeerLimit( uint16_t n )
697{
698    assert( gFd != NULL && "tr_fdInit() must be called first!" );
699    gFd->socketLimit = n;
700}
701
702uint16_t
703tr_fdGetPeerLimit( void )
704{
705    return gFd ? gFd->socketLimit : -1;
706}
707
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