source: trunk/libtransmission/fdlimit.c @ 7742

Last change on this file since 7742 was 7742, checked in by charles, 13 years ago

(trunk libT) fix a minor memory leak.

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File size: 15.1 KB
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1/******************************************************************************
2 * $Id: fdlimit.c 7742 2009-01-18 15:15:10Z 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#include <assert.h>
30#include <errno.h>
31#include <inttypes.h>
32#include <stdio.h>
33#include <stdlib.h>
34#include <string.h>
35#ifdef SYS_DARWIN
36 #include <fcntl.h>
37#endif
38
39#ifdef HAVE_FALLOCATE
40 #include <linux/falloc.h>
41#endif
42
43#include <sys/types.h>
44#include <sys/stat.h>
45#ifdef HAVE_GETRLIMIT
46 #include <sys/time.h> /* getrlimit */
47 #include <sys/resource.h> /* getrlimit */
48#endif
49#include <unistd.h>
50#include <fcntl.h> /* O_LARGEFILE */
51
52#include <event.h>
53#include <evutil.h>
54
55#include "transmission.h"
56#include "fdlimit.h"
57#include "list.h"
58#include "net.h"
59#include "platform.h" /* tr_lock */
60#include "utils.h"
61
62#define dbgmsg( ... ) \
63    do { \
64        if( tr_deepLoggingIsActive( ) ) \
65            tr_deepLog( __FILE__, __LINE__, NULL, __VA_ARGS__ ); \
66    } while( 0 )
67
68/**
69***
70**/
71
72enum
73{
74    NOFILE_BUFFER = 512, /* the process' number of open files is
75                            globalMaxPeers + NOFILE_BUFFER */
76};
77
78struct tr_openfile
79{
80    tr_bool    isCheckedOut;
81    tr_bool    isWritable;
82    tr_bool    closeWhenDone;
83    char       filename[MAX_PATH_LENGTH];
84    int        fd;
85    uint64_t   date;
86};
87
88struct tr_fd_s
89{
90    int                   socketCount;
91    int                   socketLimit;
92
93    struct tr_openfile  * openFiles;
94    int                   openFileLimit;
95
96    tr_lock             * lock;
97};
98
99static struct tr_fd_s * gFd = NULL;
100
101/***
102****
103****  Local Files
104****
105***/
106
107#ifndef O_LARGEFILE
108 #define O_LARGEFILE 0
109#endif
110
111static tr_bool
112preallocateFileSparse( int fd, uint64_t length )
113{
114    const char zero = '\0';
115
116    if( length == 0 )
117        return TRUE;
118
119    if( lseek( fd, length-1, SEEK_SET ) == -1 )
120        return FALSE;
121    if( write( fd, &zero, 1 ) == -1 )
122        return FALSE;
123    if( ftruncate( fd, length ) == -1 )
124        return FALSE;
125
126    return TRUE;
127}
128
129static tr_bool
130preallocateFileFull( const char * filename, uint64_t length )
131{
132    tr_bool success = 0;
133
134#ifdef WIN32
135
136    HANDLE hFile = CreateFile( filename, GENERIC_WRITE, 0, 0, CREATE_NEW, 0, 0 );
137    if( hFile != INVALID_HANDLE_VALUE )
138    {
139        LARGE_INTEGER li;
140        li.QuadPart = length;
141        success = SetFilePointerEx( hFile, li, NULL, FILE_BEGIN ) && SetEndOfFile( hFile );
142        CloseHandle( hFile );
143    }
144
145#else
146
147    int flags = O_RDWR | O_CREAT | O_LARGEFILE;
148    int fd = open( filename, flags, 0666 );
149    if( fd >= 0 )
150    {
151       
152# ifdef HAVE_FALLOCATE
153
154        success = !fallocate( fd, FALLOC_FL_KEEP_SIZE, 0, length );
155
156# elif defined(HAVE_POSIX_FALLOCATE)
157
158        success = !posix_fallocate( fd, 0, length );
159
160# elif defined(SYS_DARWIN)
161
162        fstore_t fst;
163        fst.fst_flags = F_ALLOCATECONTIG;
164        fst.fst_posmode = F_PEOFPOSMODE;
165        fst.fst_offset = 0;
166        fst.fst_length = length;
167        fst.fst_bytesalloc = 0;
168        success = !fcntl( fd, F_PREALLOCATE, &fst );
169
170# else
171
172        #warning no known method to preallocate files on this platform
173        success = 0;
174
175# endif
176
177        close( fd );
178    }
179
180#endif
181
182    return success;
183}
184
185/**
186 * returns 0 on success, or an errno value on failure.
187 * errno values include ENOENT if the parent folder doesn't exist,
188 * plus the errno values set by tr_mkdirp() and open().
189 */
190static int
191TrOpenFile( int                      i,
192            const char             * folder,
193            const char             * torrentFile,
194            tr_bool                  doWrite,
195            tr_preallocation_mode    preallocationMode,
196            uint64_t                 desiredFileSize )
197{
198    struct tr_openfile * file = &gFd->openFiles[i];
199    int                  flags;
200    char               * filename;
201    struct stat          sb;
202    int                  alreadyExisted;
203
204    /* confirm the parent folder exists */
205    if( stat( folder, &sb ) || !S_ISDIR( sb.st_mode ) )
206    {
207        tr_err( _( "Couldn't create \"%1$s\": parent folder \"%2$s\" does not exist" ), torrentFile, folder );
208        return ENOENT;
209    }
210
211    /* create subfolders, if any */
212    filename = tr_buildPath( folder, torrentFile, NULL );
213    if( doWrite )
214    {
215        char * tmp = tr_dirname( filename );
216        const int err = tr_mkdirp( tmp, 0777 ) ? errno : 0;
217        if( err ) {
218            tr_err( _( "Couldn't create \"%1$s\": %2$s" ), tmp, tr_strerror( err ) );
219            tr_free( tmp );
220            tr_free( filename );
221            return err;
222        }
223        tr_free( tmp );
224    }
225
226    alreadyExisted = !stat( filename, &sb ) && S_ISREG( sb.st_mode );
227
228    if( doWrite && !alreadyExisted && ( preallocationMode == TR_PREALLOCATE_FULL ) )
229        if( preallocateFileFull( filename, desiredFileSize ) )
230            tr_inf( _( "Preallocated file \"%s\"" ), filename );
231   
232    /* open the file */
233    flags = doWrite ? ( O_RDWR | O_CREAT ) : O_RDONLY;
234#ifdef O_LARGEFILE
235    flags |= O_LARGEFILE;
236#endif
237#ifdef WIN32
238    flags |= O_BINARY;
239#endif
240    file->fd = open( filename, flags, 0666 );
241    if( file->fd == -1 )
242    {
243        const int err = errno;
244        tr_err( _( "Couldn't open \"%1$s\": %2$s" ), filename, tr_strerror( err ) );
245        tr_free( filename );
246        return err;
247    }
248
249    if( doWrite && !alreadyExisted && ( preallocationMode == TR_PREALLOCATE_SPARSE ) )
250        preallocateFileSparse( file->fd, desiredFileSize );
251
252    tr_free( filename );
253    return 0;
254}
255
256static int
257fileIsOpen( const struct tr_openfile * o )
258{
259    return o->fd >= 0;
260}
261
262static void
263TrCloseFile( int i )
264{
265    struct tr_openfile * o = &gFd->openFiles[i];
266
267    assert( i >= 0 );
268    assert( i < gFd->openFileLimit );
269    assert( fileIsOpen( o ) );
270
271    close( o->fd );
272    o->fd = -1;
273    o->isCheckedOut = 0;
274}
275
276static int
277fileIsCheckedOut( const struct tr_openfile * o )
278{
279    return fileIsOpen( o ) && o->isCheckedOut;
280}
281
282/* returns an fd on success, or a -1 on failure and sets errno */
283int
284tr_fdFileCheckout( const char             * folder,
285                   const char             * torrentFile,
286                   tr_bool                  doWrite,
287                   tr_preallocation_mode    preallocationMode,
288                   uint64_t                 desiredFileSize )
289{
290    int i, winner = -1;
291    struct tr_openfile * o;
292    char filename[MAX_PATH_LENGTH];
293
294    assert( folder && *folder );
295    assert( torrentFile && *torrentFile );
296    assert( doWrite == 0 || doWrite == 1 );
297
298    tr_snprintf( filename, sizeof( filename ), "%s%c%s", folder, TR_PATH_DELIMITER, torrentFile );
299    dbgmsg( "looking for file '%s', writable %c", filename, doWrite ? 'y' : 'n' );
300
301    tr_lockLock( gFd->lock );
302
303    /* Is it already open? */
304    for( i = 0; i < gFd->openFileLimit; ++i )
305    {
306        o = &gFd->openFiles[i];
307
308        if( !fileIsOpen( o ) )
309            continue;
310
311        if( strcmp( filename, o->filename ) )
312            continue;
313
314        if( fileIsCheckedOut( o ) )
315        {
316            dbgmsg( "found it!  it's open, but checked out.  waiting..." );
317            tr_lockUnlock( gFd->lock );
318            tr_wait( 200 );
319            tr_lockLock( gFd->lock );
320            i = -1; /* reloop */
321            continue;
322        }
323
324        if( doWrite && !o->isWritable )
325        {
326            dbgmsg(
327                "found it!  it's open and available, but isn't writable. closing..." );
328            TrCloseFile( i );
329            break;
330        }
331
332        dbgmsg( "found it!  it's ready for use!" );
333        winner = i;
334        break;
335    }
336
337    dbgmsg(
338        "it's not already open.  looking for an open slot or an old file." );
339    while( winner < 0 )
340    {
341        uint64_t date = tr_date( ) + 1;
342
343        /* look for the file that's been open longest */
344        for( i = 0; i < gFd->openFileLimit; ++i )
345        {
346            o = &gFd->openFiles[i];
347
348            if( !fileIsOpen( o ) )
349            {
350                winner = i;
351                dbgmsg( "found an empty slot in %d", winner );
352                break;
353            }
354
355            if( date > o->date )
356            {
357                date = o->date;
358                winner = i;
359            }
360        }
361
362        if( winner >= 0 )
363        {
364            if( fileIsOpen( &gFd->openFiles[winner] ) )
365            {
366                dbgmsg( "closing file '%s', slot #%d",
367                        gFd->openFiles[winner].filename,
368                        winner );
369                TrCloseFile( winner );
370            }
371        }
372        else
373        {
374            dbgmsg(
375                "everything's full!  waiting for someone else to finish something" );
376            tr_lockUnlock( gFd->lock );
377            tr_wait( 200 );
378            tr_lockLock( gFd->lock );
379        }
380    }
381
382    assert( winner >= 0 );
383    o = &gFd->openFiles[winner];
384    if( !fileIsOpen( o ) )
385    {
386        const int err = TrOpenFile( winner, folder, torrentFile, doWrite, preallocationMode, desiredFileSize );
387        if( err ) {
388            tr_lockUnlock( gFd->lock );
389            errno = err;
390            return -1;
391        }
392
393        dbgmsg( "opened '%s' in slot %d, doWrite %c", filename, winner,
394                doWrite ? 'y' : 'n' );
395        tr_strlcpy( o->filename, filename, sizeof( o->filename ) );
396        o->isWritable = doWrite;
397    }
398
399    dbgmsg( "checking out '%s' in slot %d", filename, winner );
400    o->isCheckedOut = 1;
401    o->closeWhenDone = 0;
402    o->date = tr_date( );
403    tr_lockUnlock( gFd->lock );
404    return o->fd;
405}
406
407void
408tr_fdFileReturn( int fd )
409{
410    int i;
411
412    tr_lockLock( gFd->lock );
413
414    for( i = 0; i < gFd->openFileLimit; ++i )
415    {
416        struct tr_openfile * o = &gFd->openFiles[i];
417        if( o->fd != fd )
418            continue;
419
420        dbgmsg( "releasing file '%s' in slot #%d", o->filename, i );
421        o->isCheckedOut = 0;
422        if( o->closeWhenDone )
423            TrCloseFile( i );
424
425        break;
426    }
427
428    tr_lockUnlock( gFd->lock );
429}
430
431void
432tr_fdFileClose( const char * filename )
433{
434    int i;
435
436    tr_lockLock( gFd->lock );
437
438    for( i = 0; i < gFd->openFileLimit; ++i )
439    {
440        struct tr_openfile * o = &gFd->openFiles[i];
441        if( !fileIsOpen( o ) || strcmp( filename, o->filename ) )
442            continue;
443
444        dbgmsg( "tr_fdFileClose closing '%s'", filename );
445
446        if( !o->isCheckedOut )
447        {
448            dbgmsg( "not checked out, so closing it now... '%s'", filename );
449            TrCloseFile( i );
450        }
451        else
452        {
453            dbgmsg(
454                "flagging file '%s', slot #%d to be closed when checked in",
455                gFd->openFiles[i].filename, i );
456            o->closeWhenDone = 1;
457        }
458    }
459
460    tr_lockUnlock( gFd->lock );
461}
462
463/***
464****
465****  Sockets
466****
467***/
468
469static int
470getSocketMax( struct tr_fd_s * gFd )
471{
472    return gFd->socketLimit;
473}
474
475int
476tr_fdSocketCreate( int domain, int type )
477{
478    int s = -1;
479
480    tr_lockLock( gFd->lock );
481
482    if( gFd->socketCount < getSocketMax( gFd ) )
483        if( ( s = socket( domain, type, 0 ) ) < 0 )
484        {
485#ifdef SYS_DARWIN
486            if( sockerrno != EAFNOSUPPORT )
487#endif
488            tr_err( _( "Couldn't create socket: %s" ),
489                   tr_strerror( sockerrno ) );
490            s = -sockerrno;
491        }
492
493    if( s > -1 )
494        ++gFd->socketCount;
495
496    assert( gFd->socketCount >= 0 );
497
498    tr_lockUnlock( gFd->lock );
499    return s;
500}
501
502int
503tr_fdSocketAccept( int           b,
504                   tr_address  * addr,
505                   tr_port     * port )
506{
507    int                s = -1;
508    unsigned int       len;
509    struct sockaddr_storage sock;
510
511    assert( addr );
512    assert( port );
513
514    tr_lockLock( gFd->lock );
515    if( gFd->socketCount < getSocketMax( gFd ) )
516    {
517        len = sizeof( struct sockaddr_storage );
518        s = accept( b, (struct sockaddr *) &sock, &len );
519    }
520    if( s > -1 )
521    {
522        /* "The ss_family field of the sockaddr_storage structure will always
523         * align with the family field of any protocol-specific structure." */ 
524        if( sock.ss_family == AF_INET ) 
525        { 
526            struct sockaddr_in * sock4 = (struct sockaddr_in *)&sock; 
527            addr->type = TR_AF_INET; 
528            addr->addr.addr4.s_addr = sock4->sin_addr.s_addr; 
529            *port = sock4->sin_port; 
530        } 
531        else 
532        { 
533            struct sockaddr_in6 * sock6 = (struct sockaddr_in6 *)&sock; 
534            addr->type = TR_AF_INET6; 
535            addr->addr.addr6 = sock6->sin6_addr;
536            *port = sock6->sin6_port; 
537        } 
538        ++gFd->socketCount;
539    }
540    tr_lockUnlock( gFd->lock );
541
542    return s;
543}
544
545static void
546socketClose( int fd )
547{
548    EVUTIL_CLOSESOCKET( fd );
549}
550
551void
552tr_fdSocketClose( int s )
553{
554    tr_lockLock( gFd->lock );
555
556    if( s >= 0 )
557    {
558        socketClose( s );
559        --gFd->socketCount;
560    }
561
562    assert( gFd->socketCount >= 0 );
563
564    tr_lockUnlock( gFd->lock );
565}
566
567/***
568****
569****  Startup / Shutdown
570****
571***/
572
573void
574tr_fdInit( size_t openFileLimit, size_t socketLimit )
575{
576    int i;
577
578    assert( gFd == NULL );
579    gFd = tr_new0( struct tr_fd_s, 1 );
580    gFd->openFiles = tr_new0( struct tr_openfile, openFileLimit );
581    gFd->openFileLimit = openFileLimit;
582    gFd->lock = tr_lockNew( );
583
584#ifdef HAVE_GETRLIMIT
585    {
586        struct rlimit rlim;
587        getrlimit( RLIMIT_NOFILE, &rlim );
588        rlim.rlim_cur = MIN( rlim.rlim_max,
589                            (rlim_t)( socketLimit + NOFILE_BUFFER ) );
590        setrlimit( RLIMIT_NOFILE, &rlim );
591        gFd->socketLimit = rlim.rlim_cur - NOFILE_BUFFER;
592        tr_dbg( "setrlimit( RLIMIT_NOFILE, %d )", (int)rlim.rlim_cur );
593    }
594#else
595    gFd->socketLimit = socketLimit;
596#endif
597    tr_dbg( "%zu usable file descriptors", socketLimit );
598
599    for( i = 0; i < gFd->openFileLimit; ++i )
600        gFd->openFiles[i].fd = -1;
601}
602
603void
604tr_fdClose( void )
605{
606    int i = 0;
607
608    for( i = 0; i < gFd->openFileLimit; ++i )
609        if( fileIsOpen( &gFd->openFiles[i] ) )
610            TrCloseFile( i );
611
612    tr_lockFree( gFd->lock );
613
614    tr_free( gFd->openFiles );
615    tr_free( gFd );
616    gFd = NULL;
617}
618
619void
620tr_fdSetPeerLimit( uint16_t n )
621{
622    assert( gFd != NULL && "tr_fdInit() must be called first!" );
623    gFd->socketLimit = n;
624}
625
626uint16_t
627tr_fdGetPeerLimit( void )
628{
629    return gFd ? gFd->socketLimit : -1;
630}
631
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