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transmission/libtransmission/fdlimit.c

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/******************************************************************************
* $Id$
*
* Copyright (c) 2005-2008 Transmission authors and contributors
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
* DEALINGS IN THE SOFTWARE.
*****************************************************************************/
#ifndef WIN32
#define HAVE_GETRLIMIT
#endif
#ifdef HAVE_POSIX_FADVISE
#ifdef _XOPEN_SOURCE
#undef _XOPEN_SOURCE
#endif
#define _XOPEN_SOURCE 600
#endif
#include <assert.h>
#include <errno.h>
#include <inttypes.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#ifdef SYS_DARWIN
#include <fcntl.h>
#endif
#ifdef HAVE_XFS_XFS_H
#include <xfs/xfs.h>
#endif
#include <sys/types.h>
#include <sys/stat.h>
#ifdef HAVE_GETRLIMIT
#include <sys/time.h> /* getrlimit */
#include <sys/resource.h> /* getrlimit */
#endif
#include <unistd.h>
#include <fcntl.h> /* O_LARGEFILE posix_fadvise */
#include <evutil.h>
#include "transmission.h"
#include "fdlimit.h"
#include "list.h"
#include "net.h"
#include "platform.h" /* MAX_PATH_LENGTH, TR_PATH_DELIMITER */
#include "utils.h"
#define dbgmsg( ... ) \
do { \
if( tr_deepLoggingIsActive( ) ) \
tr_deepLog( __FILE__, __LINE__, NULL, __VA_ARGS__ ); \
} while( 0 )
/**
***
**/
enum
{
NOFILE_BUFFER = 512, /* the process' number of open files is
globalMaxPeers + NOFILE_BUFFER */
};
struct tr_openfile
{
tr_bool isWritable;
int torrentId;
char filename[MAX_PATH_LENGTH];
int fd;
uint64_t date;
};
struct tr_fd_s
{
int socketCount;
int socketLimit;
int openFileLimit;
struct tr_openfile * openFiles;
};
static struct tr_fd_s * gFd = NULL;
/***
****
**** Local Files
****
***/
#ifndef O_LARGEFILE
#define O_LARGEFILE 0
#endif
static tr_bool
preallocateFileSparse( int fd, uint64_t length )
{
const char zero = '\0';
if( length == 0 )
return TRUE;
if( lseek( fd, length-1, SEEK_SET ) == -1 )
return FALSE;
if( write( fd, &zero, 1 ) == -1 )
return FALSE;
if( ftruncate( fd, length ) == -1 )
return FALSE;
return TRUE;
}
static tr_bool
preallocateFileFull( const char * filename, uint64_t length )
{
tr_bool success = 0;
#ifdef WIN32
HANDLE hFile = CreateFile( filename, GENERIC_WRITE, 0, 0, CREATE_NEW, 0, 0 );
if( hFile != INVALID_HANDLE_VALUE )
{
LARGE_INTEGER li;
li.QuadPart = length;
success = SetFilePointerEx( hFile, li, NULL, FILE_BEGIN ) && SetEndOfFile( hFile );
CloseHandle( hFile );
}
#else
int flags = O_RDWR | O_CREAT | O_LARGEFILE;
int fd = open( filename, flags, 0666 );
if( fd >= 0 )
{
# ifdef HAVE_XFS_XFS_H
if( !success && platform_test_xfs_fd( fd ) )
{
xfs_flock64_t fl;
fl.l_whence = 0;
fl.l_start = 0;
fl.l_len = length;
success = !xfsctl( NULL, fd, XFS_IOC_RESVSP64, &fl );
}
# endif
# ifdef SYS_DARWIN
if( !success )
{
fstore_t fst;
fst.fst_flags = F_ALLOCATECONTIG;
fst.fst_posmode = F_PEOFPOSMODE;
fst.fst_offset = 0;
fst.fst_length = length;
fst.fst_bytesalloc = 0;
success = !fcntl( fd, F_PREALLOCATE, &fst );
}
# endif
# ifdef HAVE_POSIX_FALLOCATE
if( !success )
{
success = !posix_fallocate( fd, 0, length );
}
# endif
if( !success ) /* if nothing else works, do it the old-fashioned way */
{
uint8_t buf[ 4096 ];
memset( buf, 0, sizeof( buf ) );
success = TRUE;
while ( success && ( length > 0 ) )
{
const int thisPass = MIN( length, sizeof( buf ) );
success = write( fd, buf, thisPass ) == thisPass;
length -= thisPass;
}
}
close( fd );
}
#endif
return success;
}
tr_bool
tr_preallocate_file( const char * filename, uint64_t length )
{
return preallocateFileFull( filename, length );
}
int
tr_open_file_for_writing( const char * filename )
{
int flags = O_WRONLY | O_CREAT;
#ifdef O_BINARY
flags |= O_BINARY;
#endif
#ifdef O_LARGEFILE
flags |= O_LARGEFILE;
#endif
return open( filename, flags, 0666 );
}
int
tr_open_file_for_scanning( const char * filename )
{
int fd;
int flags;
/* build the flags */
flags = O_RDONLY;
#ifdef O_SEQUENTIAL
flags |= O_SEQUENTIAL;
#endif
#ifdef O_BINARY
flags |= O_BINARY;
#endif
#ifdef O_LARGEFILE
flags |= O_LARGEFILE;
#endif
/* open the file */
fd = open( filename, flags, 0666 );
if( fd >= 0 )
{
/* Set hints about the lookahead buffer and caching. It's okay
for these to fail silently, so don't let them affect errno */
const int err = errno;
#ifdef HAVE_POSIX_FADVISE
posix_fadvise( fd, 0, 0, POSIX_FADV_SEQUENTIAL );
#endif
#ifdef SYS_DARWIN
fcntl( fd, F_NOCACHE, 1 );
fcntl( fd, F_RDAHEAD, 1 );
#endif
errno = err;
}
return fd;
}
void
tr_close_file( int fd )
{
#if defined(HAVE_POSIX_FADVISE)
/* Set hint about not caching this file.
It's okay for this to fail silently, so don't let it affect errno */
const int err = errno;
posix_fadvise( fd, 0, 0, POSIX_FADV_DONTNEED );
errno = err;
#endif
close( fd );
}
/**
* returns 0 on success, or an errno value on failure.
* errno values include ENOENT if the parent folder doesn't exist,
* plus the errno values set by tr_mkdirp() and open().
*/
static int
TrOpenFile( int i,
const char * folder,
const char * torrentFile,
tr_bool doWrite,
tr_preallocation_mode preallocationMode,
uint64_t desiredFileSize )
{
struct tr_openfile * file = &gFd->openFiles[i];
int flags;
char * filename;
struct stat sb;
tr_bool alreadyExisted;
/* confirm the parent folder exists */
if( stat( folder, &sb ) || !S_ISDIR( sb.st_mode ) )
{
tr_err( _( "Couldn't create \"%1$s\": \"%2$s\" is not a folder" ), torrentFile, folder );
return ENOENT;
}
/* create subfolders, if any */
filename = tr_buildPath( folder, torrentFile, NULL );
if( doWrite )
{
char * tmp = tr_dirname( filename );
const int err = tr_mkdirp( tmp, 0777 ) ? errno : 0;
if( err ) {
tr_err( _( "Couldn't create \"%1$s\": %2$s" ), tmp, tr_strerror( err ) );
tr_free( tmp );
tr_free( filename );
return err;
}
tr_free( tmp );
}
alreadyExisted = !stat( filename, &sb ) && S_ISREG( sb.st_mode );
if( doWrite && !alreadyExisted && ( preallocationMode == TR_PREALLOCATE_FULL ) )
if( preallocateFileFull( filename, desiredFileSize ) )
tr_inf( _( "Preallocated file \"%s\"" ), filename );
/* open the file */
flags = doWrite ? ( O_RDWR | O_CREAT ) : O_RDONLY;
#ifdef O_SEQUENTIAL
flags |= O_SEQUENTIAL;
#endif
#ifdef O_LARGEFILE
flags |= O_LARGEFILE;
#endif
#ifdef WIN32
flags |= O_BINARY;
#endif
file->fd = open( filename, flags, 0666 );
if( file->fd == -1 )
{
const int err = errno;
tr_err( _( "Couldn't open \"%1$s\": %2$s" ), filename, tr_strerror( err ) );
tr_free( filename );
return err;
}
/* If the file already exists and it's too large, truncate it.
* This is a fringe case that happens if a torrent's been updated
* and one of the updated torrent's files is smaller.
* http://trac.transmissionbt.com/ticket/2228
* https://bugs.launchpad.net/ubuntu/+source/transmission/+bug/318249
*/
if( alreadyExisted && ( desiredFileSize < (uint64_t)sb.st_size ) )
ftruncate( file->fd, desiredFileSize );
if( doWrite && !alreadyExisted && ( preallocationMode == TR_PREALLOCATE_SPARSE ) )
preallocateFileSparse( file->fd, desiredFileSize );
#ifdef HAVE_POSIX_FADVISE
/* this doubles the OS level readahead buffer, which in practice
* turns out to be a good thing, because many (most?) clients request
* chunks of blocks in order.
* It's okay for this to fail silently, so don't let it affect errno */
{
const int err = errno;
posix_fadvise( file->fd, 0, 0, POSIX_FADV_SEQUENTIAL );
errno = err;
}
#endif
tr_free( filename );
return 0;
}
static TR_INLINE tr_bool
fileIsOpen( const struct tr_openfile * o )
{
return o->fd >= 0;
}
static void
TrCloseFile( struct tr_openfile * o )
{
assert( o != NULL );
assert( fileIsOpen( o ) );
tr_close_file( o->fd );
o->fd = -1;
}
/* returns an fd on success, or a -1 on failure and sets errno */
int
tr_fdFileCheckout( int torrentId,
const char * folder,
const char * torrentFile,
tr_bool doWrite,
tr_preallocation_mode preallocationMode,
uint64_t desiredFileSize )
{
int i, winner = -1;
struct tr_openfile * o;
char filename[MAX_PATH_LENGTH];
assert( torrentId > 0 );
assert( folder && *folder );
assert( torrentFile && *torrentFile );
assert( tr_isBool( doWrite ) );
tr_snprintf( filename, sizeof( filename ), "%s%c%s", folder, TR_PATH_DELIMITER, torrentFile );
dbgmsg( "looking for file '%s', writable %c", filename, doWrite ? 'y' : 'n' );
/* is it already open? */
for( i=0; i<gFd->openFileLimit; ++i )
{
o = &gFd->openFiles[i];
if( !fileIsOpen( o ) )
continue;
if( torrentId != o->torrentId )
continue;
if( strcmp( filename, o->filename ) )
continue;
if( doWrite && !o->isWritable )
{
dbgmsg( "found it! it's open and available, but isn't writable. closing..." );
TrCloseFile( o );
break;
}
dbgmsg( "found it! it's ready for use!" );
winner = i;
break;
}
dbgmsg( "it's not already open. looking for an open slot or an old file." );
while( winner < 0 )
{
uint64_t date = tr_date( ) + 1;
/* look for the file that's been open longest */
for( i=0; i<gFd->openFileLimit; ++i )
{
o = &gFd->openFiles[i];
if( !fileIsOpen( o ) )
{
winner = i;
dbgmsg( "found an empty slot in %d", winner );
break;
}
if( date > o->date )
{
date = o->date;
winner = i;
}
}
assert( winner >= 0 );
if( fileIsOpen( &gFd->openFiles[winner] ) )
{
dbgmsg( "closing file \"%s\"", gFd->openFiles[winner].filename );
TrCloseFile( &gFd->openFiles[winner] );
}
}
assert( winner >= 0 );
o = &gFd->openFiles[winner];
if( !fileIsOpen( o ) )
{
const int err = TrOpenFile( winner, folder, torrentFile, doWrite,
preallocationMode, desiredFileSize );
if( err ) {
errno = err;
return -1;
}
dbgmsg( "opened '%s' in slot %d, doWrite %c", filename, winner,
doWrite ? 'y' : 'n' );
tr_strlcpy( o->filename, filename, sizeof( o->filename ) );
o->isWritable = doWrite;
}
dbgmsg( "checking out '%s' in slot %d", filename, winner );
o->torrentId = torrentId;
o->date = tr_date( );
return o->fd;
}
void
tr_fdFileClose( const char * filename )
{
struct tr_openfile * o;
const struct tr_openfile * end;
for( o=gFd->openFiles, end=o+gFd->openFileLimit; o!=end; ++o )
{
if( !fileIsOpen( o ) || strcmp( filename, o->filename ) )
continue;
dbgmsg( "tr_fdFileClose closing \"%s\"", filename );
TrCloseFile( o );
}
}
void
tr_fdTorrentClose( int torrentId )
{
struct tr_openfile * o;
const struct tr_openfile * end;
for( o=gFd->openFiles, end=o+gFd->openFileLimit; o!=end; ++o )
if( fileIsOpen( o ) && o->torrentId == torrentId )
TrCloseFile( o );
}
/***
****
**** Sockets
****
***/
static TR_INLINE int
getSocketMax( struct tr_fd_s * gFd )
{
return gFd->socketLimit;
}
int
tr_fdSocketCreate( int domain, int type )
{
int s = -1;
if( gFd->socketCount < getSocketMax( gFd ) )
if( ( s = socket( domain, type, 0 ) ) < 0 )
{
if( sockerrno != EAFNOSUPPORT )
tr_err( _( "Couldn't create socket: %s" ),
tr_strerror( sockerrno ) );
}
if( s > -1 )
++gFd->socketCount;
assert( gFd->socketCount >= 0 );
return s;
}
int
tr_fdSocketAccept( int b,
tr_address * addr,
tr_port * port )
{
int s;
unsigned int len;
struct sockaddr_storage sock;
assert( addr );
assert( port );
len = sizeof( struct sockaddr_storage );
s = accept( b, (struct sockaddr *) &sock, &len );
if( ( s >= 0 ) && gFd->socketCount > getSocketMax( gFd ) )
{
EVUTIL_CLOSESOCKET( s );
s = -1;
}
if( s >= 0 )
{
/* "The ss_family field of the sockaddr_storage structure will always
* align with the family field of any protocol-specific structure." */
if( sock.ss_family == AF_INET )
{
struct sockaddr_in *si;
union { struct sockaddr_storage dummy; struct sockaddr_in si; } s;
s.dummy = sock;
si = &s.si;
addr->type = TR_AF_INET;
addr->addr.addr4.s_addr = si->sin_addr.s_addr;
*port = si->sin_port;
}
else
{
struct sockaddr_in6 *si;
union { struct sockaddr_storage dummy; struct sockaddr_in6 si; } s;
s.dummy = sock;
si = &s.si;
addr->type = TR_AF_INET6;
addr->addr.addr6 = si->sin6_addr;
*port = si->sin6_port;
}
++gFd->socketCount;
}
return s;
}
void
tr_fdSocketClose( int fd )
{
if( fd >= 0 )
{
EVUTIL_CLOSESOCKET( fd );
--gFd->socketCount;
}
assert( gFd->socketCount >= 0 );
}
/***
****
**** Startup / Shutdown
****
***/
void
tr_fdInit( size_t openFileLimit, size_t socketLimit )
{
int i;
assert( gFd == NULL );
gFd = tr_new0( struct tr_fd_s, 1 );
gFd->openFiles = tr_new0( struct tr_openfile, openFileLimit );
gFd->openFileLimit = openFileLimit;
#ifdef HAVE_GETRLIMIT
{
struct rlimit rlim;
getrlimit( RLIMIT_NOFILE, &rlim );
rlim.rlim_cur = MIN( rlim.rlim_max,
(rlim_t)( socketLimit + NOFILE_BUFFER ) );
setrlimit( RLIMIT_NOFILE, &rlim );
gFd->socketLimit = rlim.rlim_cur - NOFILE_BUFFER;
tr_dbg( "setrlimit( RLIMIT_NOFILE, %d )", (int)rlim.rlim_cur );
}
#else
gFd->socketLimit = socketLimit;
#endif
tr_dbg( "%zu usable file descriptors", socketLimit );
for( i = 0; i < gFd->openFileLimit; ++i )
gFd->openFiles[i].fd = -1;
}
void
tr_fdClose( void )
{
struct tr_openfile * o;
const struct tr_openfile * end;
for( o=gFd->openFiles, end=o+gFd->openFileLimit; o!=end; ++o )
if( fileIsOpen( o ) )
TrCloseFile( o );
tr_free( gFd->openFiles );
tr_free( gFd );
gFd = NULL;
}
void
tr_fdSetPeerLimit( uint16_t n )
{
assert( gFd != NULL && "tr_fdInit() must be called first!" );
gFd->socketLimit = n;
}
uint16_t
tr_fdGetPeerLimit( void )
{
return gFd ? gFd->socketLimit : -1;
}
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