source: trunk/libtransmission/fdlimit.c @ 8122

Last change on this file since 8122 was 8122, checked in by charles, 13 years ago

(trunk) modify tr_torrentParse() and tr_torrentNew() arguments s.t. they use the ctor's session instead of passing it in again. Allow a NULL session pointer for some cases of tr_torrentParse().

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File size: 16.0 KB
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1/******************************************************************************
2 * $Id: fdlimit.c 8122 2009-04-02 17:30:29Z 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#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" /* tr_lock */
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    SYNC_INTERVAL = 15   /* (arbitrary number) how many seconds to go
84                            between fsync calls for files in heavy use */
85};
86
87struct tr_openfile
88{
89    tr_bool    isCheckedOut;
90    tr_bool    isWritable;
91    tr_bool    closeWhenDone;
92    char       filename[MAX_PATH_LENGTH];
93    int        fd;
94    uint64_t   date;
95    time_t     syncAt;
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       
162# ifdef HAVE_FALLOCATE
163
164        success = !fallocate( fd, FALLOC_FL_KEEP_SIZE, 0, length );
165
166# elif defined(HAVE_POSIX_FALLOCATE)
167
168        success = !posix_fallocate( fd, 0, length );
169
170# elif defined(SYS_DARWIN)
171
172        fstore_t fst;
173        fst.fst_flags = F_ALLOCATECONTIG;
174        fst.fst_posmode = F_PEOFPOSMODE;
175        fst.fst_offset = 0;
176        fst.fst_length = length;
177        fst.fst_bytesalloc = 0;
178        success = !fcntl( fd, F_PREALLOCATE, &fst );
179
180# else
181
182        #warning no known method to preallocate files on this platform
183        success = 0;
184
185# endif
186
187        close( fd );
188    }
189
190#endif
191
192    return success;
193}
194
195/**
196 * returns 0 on success, or an errno value on failure.
197 * errno values include ENOENT if the parent folder doesn't exist,
198 * plus the errno values set by tr_mkdirp() and open().
199 */
200static int
201TrOpenFile( int                      i,
202            const char             * folder,
203            const char             * torrentFile,
204            tr_bool                  doWrite,
205            tr_preallocation_mode    preallocationMode,
206            uint64_t                 desiredFileSize )
207{
208    struct tr_openfile * file = &gFd->openFiles[i];
209    int                  flags;
210    char               * filename;
211    struct stat          sb;
212    int                  alreadyExisted;
213
214    /* confirm the parent folder exists */
215    if( stat( folder, &sb ) || !S_ISDIR( sb.st_mode ) )
216    {
217        tr_err( _( "Couldn't create \"%1$s\": parent folder \"%2$s\" does not exist" ), torrentFile, folder );
218        return ENOENT;
219    }
220
221    /* create subfolders, if any */
222    filename = tr_buildPath( folder, torrentFile, NULL );
223    if( doWrite )
224    {
225        char * tmp = tr_dirname( filename );
226        const int err = tr_mkdirp( tmp, 0777 ) ? errno : 0;
227        if( err ) {
228            tr_err( _( "Couldn't create \"%1$s\": %2$s" ), tmp, tr_strerror( err ) );
229            tr_free( tmp );
230            tr_free( filename );
231            return err;
232        }
233        tr_free( tmp );
234    }
235
236    alreadyExisted = !stat( filename, &sb ) && S_ISREG( sb.st_mode );
237
238    if( doWrite && !alreadyExisted && ( preallocationMode == TR_PREALLOCATE_FULL ) )
239        if( preallocateFileFull( filename, desiredFileSize ) )
240            tr_inf( _( "Preallocated file \"%s\"" ), filename );
241   
242    /* open the file */
243    flags = doWrite ? ( O_RDWR | O_CREAT ) : O_RDONLY;
244#ifdef O_RANDOM
245    flags |= O_RANDOM
246#endif
247#ifdef O_LARGEFILE
248    flags |= O_LARGEFILE;
249#endif
250#ifdef WIN32
251    flags |= O_BINARY;
252#endif
253    file->fd = open( filename, flags, 0666 );
254    if( file->fd == -1 )
255    {
256        const int err = errno;
257        tr_err( _( "Couldn't open \"%1$s\": %2$s" ), filename, tr_strerror( err ) );
258        tr_free( filename );
259        return err;
260    }
261
262    if( doWrite && !alreadyExisted && ( preallocationMode == TR_PREALLOCATE_SPARSE ) )
263        preallocateFileSparse( file->fd, desiredFileSize );
264
265#if defined( SYS_DARWIN )
266    fcntl( file->fd, F_NOCACHE, 1 );
267    fcntl( file->fd, F_RDAHEAD, 0 );
268#elif defined( HAVE_POSIX_FADVISE )
269    posix_fadvise( file->fd, 0, 0, POSIX_FADV_RANDOM );
270#endif
271
272    tr_free( filename );
273    return 0;
274}
275
276static int
277fileIsOpen( const struct tr_openfile * o )
278{
279    return o->fd >= 0;
280}
281
282static void
283TrCloseFile( int i )
284{
285    struct tr_openfile * o = &gFd->openFiles[i];
286
287    assert( i >= 0 );
288    assert( i < gFd->openFileLimit );
289    assert( fileIsOpen( o ) );
290
291    close( o->fd );
292    o->fd = -1;
293    o->isCheckedOut = 0;
294}
295
296static int
297fileIsCheckedOut( const struct tr_openfile * o )
298{
299    return fileIsOpen( o ) && o->isCheckedOut;
300}
301
302/* returns an fd on success, or a -1 on failure and sets errno */
303int
304tr_fdFileCheckout( const char             * folder,
305                   const char             * torrentFile,
306                   tr_bool                  doWrite,
307                   tr_preallocation_mode    preallocationMode,
308                   uint64_t                 desiredFileSize )
309{
310    int i, winner = -1;
311    struct tr_openfile * o;
312    char filename[MAX_PATH_LENGTH];
313
314    assert( folder && *folder );
315    assert( torrentFile && *torrentFile );
316    assert( doWrite == 0 || doWrite == 1 );
317
318    tr_snprintf( filename, sizeof( filename ), "%s%c%s", folder, TR_PATH_DELIMITER, torrentFile );
319    dbgmsg( "looking for file '%s', writable %c", filename, doWrite ? 'y' : 'n' );
320
321    tr_lockLock( gFd->lock );
322
323    /* Is it already open? */
324    for( i = 0; i < gFd->openFileLimit; ++i )
325    {
326        o = &gFd->openFiles[i];
327
328        if( !fileIsOpen( o ) )
329            continue;
330
331        if( strcmp( filename, o->filename ) )
332            continue;
333
334        if( fileIsCheckedOut( o ) )
335        {
336            dbgmsg( "found it!  it's open, but checked out.  waiting..." );
337            tr_lockUnlock( gFd->lock );
338            tr_wait( 200 );
339            tr_lockLock( gFd->lock );
340            i = -1; /* reloop */
341            continue;
342        }
343
344        if( doWrite && !o->isWritable )
345        {
346            dbgmsg(
347                "found it!  it's open and available, but isn't writable. closing..." );
348            TrCloseFile( i );
349            break;
350        }
351
352        dbgmsg( "found it!  it's ready for use!" );
353        winner = i;
354        break;
355    }
356
357    dbgmsg(
358        "it's not already open.  looking for an open slot or an old file." );
359    while( winner < 0 )
360    {
361        uint64_t date = tr_date( ) + 1;
362
363        /* look for the file that's been open longest */
364        for( i = 0; i < gFd->openFileLimit; ++i )
365        {
366            o = &gFd->openFiles[i];
367
368            if( !fileIsOpen( o ) )
369            {
370                winner = i;
371                dbgmsg( "found an empty slot in %d", winner );
372                break;
373            }
374
375            if( date > o->date )
376            {
377                date = o->date;
378                winner = i;
379            }
380        }
381
382        if( winner >= 0 )
383        {
384            if( fileIsOpen( &gFd->openFiles[winner] ) )
385            {
386                dbgmsg( "closing file '%s', slot #%d",
387                        gFd->openFiles[winner].filename,
388                        winner );
389                TrCloseFile( winner );
390            }
391        }
392        else
393        {
394            dbgmsg( "everything's full!  waiting for someone else to finish something" );
395            tr_lockUnlock( gFd->lock );
396            tr_wait( 200 );
397            tr_lockLock( gFd->lock );
398        }
399    }
400
401    assert( winner >= 0 );
402    o = &gFd->openFiles[winner];
403    if( !fileIsOpen( o ) )
404    {
405        const int err = TrOpenFile( winner, folder, torrentFile, doWrite, preallocationMode, desiredFileSize );
406        if( err ) {
407            tr_lockUnlock( gFd->lock );
408            errno = err;
409            return -1;
410        }
411
412        dbgmsg( "opened '%s' in slot %d, doWrite %c", filename, winner,
413                doWrite ? 'y' : 'n' );
414        tr_strlcpy( o->filename, filename, sizeof( o->filename ) );
415        o->isWritable = doWrite;
416        o->syncAt = time( NULL ) + SYNC_INTERVAL;
417    }
418
419    dbgmsg( "checking out '%s' in slot %d", filename, winner );
420    o->isCheckedOut = 1;
421    o->closeWhenDone = 0;
422    o->date = tr_date( );
423    tr_lockUnlock( gFd->lock );
424    return o->fd;
425}
426
427void
428tr_fdFileReturn( int fd )
429{
430    int i;
431
432    tr_lockLock( gFd->lock );
433
434    for( i = 0; i < gFd->openFileLimit; ++i )
435    {
436        struct tr_openfile * o = &gFd->openFiles[i];
437        if( o->fd != fd )
438            continue;
439
440        dbgmsg( "releasing file '%s' in slot #%d", o->filename, i );
441        o->isCheckedOut = 0;
442        if( o->closeWhenDone )
443            TrCloseFile( i );
444        else if( o->syncAt <= time( NULL ) ) {
445            dbgmsg( "fsync()ing file '%s' in slot #%d", o->filename, i );
446            //fsync( o->fd );
447#ifdef HAVE_POSIX_FADVISE
448            /* TODO: test performance with and without this */
449            posix_fadvise( o->fd, 0, 0, POSIX_FADV_DONTNEED );
450#endif
451            o->syncAt = time( NULL ) + SYNC_INTERVAL;
452        }
453
454        break;
455    }
456
457    tr_lockUnlock( gFd->lock );
458}
459
460void
461tr_fdFileClose( const char * filename )
462{
463    int i;
464
465    tr_lockLock( gFd->lock );
466
467    for( i = 0; i < gFd->openFileLimit; ++i )
468    {
469        struct tr_openfile * o = &gFd->openFiles[i];
470        if( !fileIsOpen( o ) || strcmp( filename, o->filename ) )
471            continue;
472
473        dbgmsg( "tr_fdFileClose closing '%s'", filename );
474
475        if( !o->isCheckedOut )
476        {
477            dbgmsg( "not checked out, so closing it now... '%s'", filename );
478            TrCloseFile( i );
479        }
480        else
481        {
482            dbgmsg(
483                "flagging file '%s', slot #%d to be closed when checked in",
484                gFd->openFiles[i].filename, i );
485            o->closeWhenDone = 1;
486        }
487    }
488
489    tr_lockUnlock( gFd->lock );
490}
491
492/***
493****
494****  Sockets
495****
496***/
497
498static int
499getSocketMax( struct tr_fd_s * gFd )
500{
501    return gFd->socketLimit;
502}
503
504int
505tr_fdSocketCreate( int domain, int type )
506{
507    int s = -1;
508
509    tr_lockLock( gFd->lock );
510
511    if( gFd->socketCount < getSocketMax( gFd ) )
512        if( ( s = socket( domain, type, 0 ) ) < 0 )
513        {
514#ifdef SYS_DARWIN
515            if( sockerrno != EAFNOSUPPORT )
516#endif
517            tr_err( _( "Couldn't create socket: %s" ),
518                   tr_strerror( sockerrno ) );
519            s = -sockerrno;
520        }
521
522    if( s > -1 )
523        ++gFd->socketCount;
524
525    assert( gFd->socketCount >= 0 );
526
527    tr_lockUnlock( gFd->lock );
528    return s;
529}
530
531int
532tr_fdSocketAccept( int           b,
533                   tr_address  * addr,
534                   tr_port     * port )
535{
536    int                s = -1;
537    unsigned int       len;
538    struct sockaddr_storage sock;
539
540    assert( addr );
541    assert( port );
542
543    tr_lockLock( gFd->lock );
544    if( gFd->socketCount < getSocketMax( gFd ) )
545    {
546        len = sizeof( struct sockaddr_storage );
547        s = accept( b, (struct sockaddr *) &sock, &len );
548    }
549    if( s > -1 )
550    {
551        /* "The ss_family field of the sockaddr_storage structure will always
552         * align with the family field of any protocol-specific structure." */ 
553        if( sock.ss_family == AF_INET ) 
554        { 
555            struct sockaddr_in * sock4 = (struct sockaddr_in *)&sock; 
556            addr->type = TR_AF_INET; 
557            addr->addr.addr4.s_addr = sock4->sin_addr.s_addr; 
558            *port = sock4->sin_port; 
559        } 
560        else 
561        { 
562            struct sockaddr_in6 * sock6 = (struct sockaddr_in6 *)&sock; 
563            addr->type = TR_AF_INET6; 
564            addr->addr.addr6 = sock6->sin6_addr;
565            *port = sock6->sin6_port; 
566        } 
567        ++gFd->socketCount;
568    }
569    tr_lockUnlock( gFd->lock );
570
571    return s;
572}
573
574static void
575socketClose( int fd )
576{
577    EVUTIL_CLOSESOCKET( fd );
578}
579
580void
581tr_fdSocketClose( int s )
582{
583    tr_lockLock( gFd->lock );
584
585    if( s >= 0 )
586    {
587        socketClose( s );
588        --gFd->socketCount;
589    }
590
591    assert( gFd->socketCount >= 0 );
592
593    tr_lockUnlock( gFd->lock );
594}
595
596/***
597****
598****  Startup / Shutdown
599****
600***/
601
602void
603tr_fdInit( size_t openFileLimit, size_t socketLimit )
604{
605    int i;
606
607    assert( gFd == NULL );
608    gFd = tr_new0( struct tr_fd_s, 1 );
609    gFd->openFiles = tr_new0( struct tr_openfile, openFileLimit );
610    gFd->openFileLimit = openFileLimit;
611    gFd->lock = tr_lockNew( );
612
613#ifdef HAVE_GETRLIMIT
614    {
615        struct rlimit rlim;
616        getrlimit( RLIMIT_NOFILE, &rlim );
617        rlim.rlim_cur = MIN( rlim.rlim_max,
618                            (rlim_t)( socketLimit + NOFILE_BUFFER ) );
619        setrlimit( RLIMIT_NOFILE, &rlim );
620        gFd->socketLimit = rlim.rlim_cur - NOFILE_BUFFER;
621        tr_dbg( "setrlimit( RLIMIT_NOFILE, %d )", (int)rlim.rlim_cur );
622    }
623#else
624    gFd->socketLimit = socketLimit;
625#endif
626    tr_dbg( "%zu usable file descriptors", socketLimit );
627
628    for( i = 0; i < gFd->openFileLimit; ++i )
629        gFd->openFiles[i].fd = -1;
630}
631
632void
633tr_fdClose( void )
634{
635    int i = 0;
636
637    for( i = 0; i < gFd->openFileLimit; ++i )
638        if( fileIsOpen( &gFd->openFiles[i] ) )
639            TrCloseFile( i );
640
641    tr_lockFree( gFd->lock );
642
643    tr_free( gFd->openFiles );
644    tr_free( gFd );
645    gFd = NULL;
646}
647
648void
649tr_fdSetPeerLimit( uint16_t n )
650{
651    assert( gFd != NULL && "tr_fdInit() must be called first!" );
652    gFd->socketLimit = n;
653}
654
655uint16_t
656tr_fdGetPeerLimit( void )
657{
658    return gFd ? gFd->socketLimit : -1;
659}
660
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