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transmission/libtransmission/fdlimit.c

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/*
* This file Copyright (C) Mnemosyne LLC
*
* This file is licensed by the GPL version 2. Works owned by the
* Transmission project are granted a special exemption to clause 2(b)
* so that the bulk of its code can remain under the MIT license.
* This exemption does not extend to derived works not owned by
* the Transmission project.
*
* $Id$
*/
#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 <string.h>
#ifdef SYS_DARWIN
#include <fcntl.h>
#endif
#ifdef HAVE_FALLOCATE64
/* FIXME can't find the right #include voodoo to pick up the declaration.. */
extern int fallocate64( int fd, int mode, uint64_t offset, uint64_t len );
#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 <fcntl.h> /* O_LARGEFILE posix_fadvise */
#include <unistd.h> /* lseek(), write(), ftruncate(), pread(), pwrite(), etc */
#include "transmission.h"
#include "fdlimit.h"
#include "net.h"
#include "session.h"
#include "torrent.h" /* tr_isTorrent() */
#define dbgmsg( ... ) \
do { \
if( tr_deepLoggingIsActive( ) ) \
tr_deepLog( __FILE__, __LINE__, NULL, __VA_ARGS__ ); \
} while( 0 )
/***
****
**** Local Files
****
***/
#ifndef O_LARGEFILE
#define O_LARGEFILE 0
#endif
#ifndef O_BINARY
#define O_BINARY 0
#endif
#ifndef O_SEQUENTIAL
#define O_SEQUENTIAL 0
#endif
static bool
preallocate_file_sparse( int fd, uint64_t length )
{
const char zero = '\0';
bool success = 0;
if( !length )
success = true;
#ifdef HAVE_FALLOCATE64
if( !success ) /* fallocate64 is always preferred, so try it first */
success = !fallocate64( fd, 0, 0, length );
#endif
if( !success ) /* fallback: the old-style seek-and-write */
success = ( lseek( fd, length-1, SEEK_SET ) != -1 )
&& ( write( fd, &zero, 1 ) != -1 )
&& ( ftruncate( fd, length ) != -1 );
return success;
}
static bool
preallocate_file_full( const char * filename, uint64_t length )
{
bool success = 0;
#ifdef WIN32
HANDLE hFile = CreateFile( filename, GENERIC_WRITE, 0, 0, CREATE_NEW, FILE_FLAG_RANDOM_ACCESS, 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_FALLOCATE64
if( !success )
{
success = !fallocate64( fd, 0, 0, length );
}
# endif
# 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;
}
/* portability wrapper for fsync(). */
int
tr_fsync( int fd )
{
#ifdef WIN32
return _commit( fd );
#else
return fsync( fd );
#endif
}
/* Like pread and pwrite, except that the position is undefined afterwards.
And of course they are not thread-safe. */
/* don't use pread/pwrite on old versions of uClibc because they're buggy.
* https://trac.transmissionbt.com/ticket/3826 */
#ifdef __UCLIBC__
#define TR_UCLIBC_CHECK_VERSION(major,minor,micro) \
(__UCLIBC_MAJOR__ > (major) || \
(__UCLIBC_MAJOR__ == (major) && __UCLIBC_MINOR__ > (minor)) || \
(__UCLIBC_MAJOR__ == (major) && __UCLIBC_MINOR__ == (minor) && \
__UCLIBC_SUBLEVEL__ >= (micro)))
#if !TR_UCLIBC_CHECK_VERSION(0,9,28)
#undef HAVE_PREAD
#undef HAVE_PWRITE
#endif
#endif
#ifdef SYS_DARWIN
#define HAVE_PREAD
#define HAVE_PWRITE
#endif
ssize_t
tr_pread( int fd, void *buf, size_t count, off_t offset )
{
#ifdef HAVE_PREAD
return pread( fd, buf, count, offset );
#else
const off_t lrc = lseek( fd, offset, SEEK_SET );
if( lrc < 0 )
return -1;
return read( fd, buf, count );
#endif
}
ssize_t
tr_pwrite( int fd, const void *buf, size_t count, off_t offset )
{
#ifdef HAVE_PWRITE
return pwrite( fd, buf, count, offset );
#else
const off_t lrc = lseek( fd, offset, SEEK_SET );
if( lrc < 0 )
return -1;
return write( fd, buf, count );
#endif
}
int
tr_prefetch( int fd UNUSED, off_t offset UNUSED, size_t count UNUSED )
{
#ifdef HAVE_POSIX_FADVISE
return posix_fadvise( fd, offset, count, POSIX_FADV_WILLNEED );
#elif defined(SYS_DARWIN)
struct radvisory radv;
radv.ra_offset = offset;
radv.ra_count = count;
return fcntl( fd, F_RDADVISE, &radv );
#else
return 0;
#endif
}
void
tr_set_file_for_single_pass( int fd )
{
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_RDAHEAD, 1 );
fcntl( fd, F_NOCACHE, 1 );
#endif
errno = err;
}
}
static int
open_local_file( const char * filename, int flags )
{
const int fd = open( filename, flags, 0666 );
tr_set_file_for_single_pass( fd );
return fd;
}
int
tr_open_file_for_writing( const char * filename )
{
return open_local_file( filename, O_LARGEFILE|O_BINARY|O_CREAT|O_WRONLY );
}
int
tr_open_file_for_scanning( const char * filename )
{
return open_local_file( filename, O_LARGEFILE|O_BINARY|O_SEQUENTIAL|O_RDONLY );
}
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
#ifdef SYS_DARWIN
/* it's unclear to me from the man pages if this actually flushes out the cache,
* but it couldn't hurt... */
fcntl( fd, F_NOCACHE, 1 );
#endif
close( fd );
}
/*****
******
******
******
*****/
struct tr_cached_file
{
bool is_writable;
int fd;
int torrent_id;
tr_file_index_t file_index;
time_t used_at;
};
static inline bool
cached_file_is_open( const struct tr_cached_file * o )
{
assert( o != NULL );
return o->fd >= 0;
}
static void
cached_file_close( struct tr_cached_file * o )
{
assert( cached_file_is_open( o ) );
tr_close_file( o->fd );
o->fd = -1;
}
/**
* 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
cached_file_open( struct tr_cached_file * o,
const char * existing_dir,
const char * filename,
bool writable,
tr_preallocation_mode allocation,
uint64_t file_size )
{
int flags;
struct stat sb;
bool alreadyExisted;
/* confirm that existing_dir, if specified, exists on the disk */
if( existing_dir && *existing_dir && stat( existing_dir, &sb ) )
{
const int err = errno;
tr_err( _( "Couldn't open \"%1$s\": %2$s" ), existing_dir, tr_strerror( err ) );
return err;
}
/* create subfolders, if any */
if( writable )
{
char * dir = tr_dirname( filename );
const int err = tr_mkdirp( dir, 0777 ) ? errno : 0;
if( err ) {
tr_err( _( "Couldn't create \"%1$s\": %2$s" ), dir, tr_strerror( err ) );
tr_free( dir );
return err;
}
tr_free( dir );
}
alreadyExisted = !stat( filename, &sb ) && S_ISREG( sb.st_mode );
if( writable && !alreadyExisted && ( allocation == TR_PREALLOCATE_FULL ) )
if( preallocate_file_full( filename, file_size ) )
tr_dbg( "Preallocated file \"%s\"", filename );
/* open the file */
flags = writable ? ( O_RDWR | O_CREAT ) : O_RDONLY;
flags |= O_LARGEFILE | O_BINARY | O_SEQUENTIAL;
o->fd = open( filename, flags, 0666 );
if( o->fd == -1 )
{
const int err = errno;
tr_err( _( "Couldn't open \"%1$s\": %2$s" ), filename, tr_strerror( err ) );
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 && ( file_size < (uint64_t)sb.st_size ) )
{
if( ftruncate( o->fd, file_size ) == -1 )
{
const int err = errno;
tr_err( _( "Couldn't truncate \"%1$s\": %2$s" ), filename, tr_strerror( err ) );
return err;
}
}
if( writable && !alreadyExisted && ( allocation == TR_PREALLOCATE_SPARSE ) )
preallocate_file_sparse( o->fd, file_size );
/* Many (most?) clients request blocks in ascending order,
* so increase the readahead buffer.
* Also, disable OS-level caching because "inactive memory" angers users. */
tr_set_file_for_single_pass( o->fd );
return 0;
}
/***
****
***/
struct tr_fileset
{
struct tr_cached_file * begin;
const struct tr_cached_file * end;
};
static void
fileset_construct( struct tr_fileset * set, int n )
{
struct tr_cached_file * o;
const struct tr_cached_file TR_CACHED_FILE_INIT = { 0, -1, 0, 0, 0 };
set->begin = tr_new( struct tr_cached_file, n );
set->end = set->begin + n;
for( o=set->begin; o!=set->end; ++o )
*o = TR_CACHED_FILE_INIT;
}
static void
fileset_close_all( struct tr_fileset * set )
{
struct tr_cached_file * o;
if( set != NULL )
for( o=set->begin; o!=set->end; ++o )
if( cached_file_is_open( o ) )
cached_file_close( o );
}
static void
fileset_destruct( struct tr_fileset * set )
{
fileset_close_all( set );
tr_free( set->begin );
set->end = set->begin = NULL;
}
static void
fileset_close_torrent( struct tr_fileset * set, int torrent_id )
{
struct tr_cached_file * o;
if( set != NULL )
for( o=set->begin; o!=set->end; ++o )
if( ( o->torrent_id == torrent_id ) && cached_file_is_open( o ) )
cached_file_close( o );
}
static struct tr_cached_file *
fileset_lookup( struct tr_fileset * set, int torrent_id, tr_file_index_t i )
{
struct tr_cached_file * o;
if( set != NULL )
for( o=set->begin; o!=set->end; ++o )
if( ( torrent_id == o->torrent_id ) && ( i == o->file_index ) && cached_file_is_open( o ) )
return o;
return NULL;
}
static struct tr_cached_file *
fileset_get_empty_slot( struct tr_fileset * set )
{
struct tr_cached_file * o;
struct tr_cached_file * cull;
/* try to find an unused slot */
for( o=set->begin; o!=set->end; ++o )
if( !cached_file_is_open( o ) )
return o;
/* all slots are full... recycle the least recently used */
for( cull=NULL, o=set->begin; o!=set->end; ++o )
if( !cull || o->used_at < cull->used_at )
cull = o;
cached_file_close( cull );
return cull;
}
/***
****
**** Startup / Shutdown
****
***/
struct tr_fdInfo
{
int peerCount;
struct tr_fileset fileset;
};
static void
ensureSessionFdInfoExists( tr_session * session )
{
assert( tr_isSession( session ) );
if( session->fdInfo == NULL )
{
const int TR_MAX_OPEN_FILES = 32;
struct tr_fdInfo * i = tr_new0( struct tr_fdInfo, 1 );
fileset_construct( &i->fileset, TR_MAX_OPEN_FILES );
session->fdInfo = i;
}
}
void
tr_fdClose( tr_session * session )
{
if( session && session->fdInfo )
{
struct tr_fdInfo * i = session->fdInfo;
fileset_destruct( &i->fileset );
tr_free( i );
session->fdInfo = NULL;
}
}
/***
****
***/
static struct tr_fileset*
get_fileset( tr_session * session )
{
if( !session )
return NULL;
ensureSessionFdInfoExists( session );
return &session->fdInfo->fileset;
}
void
tr_fdFileClose( tr_session * s, const tr_torrent * tor, tr_file_index_t i )
{
struct tr_cached_file * o;
if(( o = fileset_lookup( get_fileset( s ), tr_torrentId( tor ), i )))
{
/* flush writable files so that their mtimes will be
* up-to-date when this function returns to the caller... */
if( o->is_writable )
tr_fsync( o->fd );
cached_file_close( o );
}
}
int
tr_fdFileGetCached( tr_session * s, int torrent_id, tr_file_index_t i, bool writable )
{
struct tr_cached_file * o = fileset_lookup( get_fileset( s ), torrent_id, i );
if( !o || ( writable && !o->is_writable ) )
return -1;
o->used_at = tr_time( );
return o->fd;
}
#ifdef SYS_DARWIN
#define TR_STAT_MTIME(sb) ((sb).st_mtimespec.tv_sec)
#else
#define TR_STAT_MTIME(sb) ((sb).st_mtime)
#endif
bool
tr_fdFileGetCachedMTime( tr_session * s, int torrent_id, tr_file_index_t i, time_t * mtime )
{
bool success;
struct stat sb;
struct tr_cached_file * o = fileset_lookup( get_fileset( s ), torrent_id, i );
if(( success = ( o != NULL ) && !fstat( o->fd, &sb )))
*mtime = TR_STAT_MTIME( sb );
return success;
}
void
tr_fdTorrentClose( tr_session * session, int torrent_id )
{
fileset_close_torrent( get_fileset( session ), torrent_id );
}
/* returns an fd on success, or a -1 on failure and sets errno */
int
tr_fdFileCheckout( tr_session * session,
int torrent_id,
tr_file_index_t i,
const char * existing_dir,
const char * filename,
bool writable,
tr_preallocation_mode allocation,
uint64_t file_size )
{
struct tr_fileset * set = get_fileset( session );
struct tr_cached_file * o = fileset_lookup( set, torrent_id, i );
if( o && writable && !o->is_writable )
cached_file_close( o ); /* close it so we can reopen in rw mode */
else if( !o )
o = fileset_get_empty_slot( set );
if( !cached_file_is_open( o ) )
{
const int err = cached_file_open( o, existing_dir, filename, writable, allocation, file_size );
if( err ) {
errno = err;
return -1;
}
dbgmsg( "opened '%s' writable %c", filename, writable?'y':'n' );
o->is_writable = writable;
}
dbgmsg( "checking out '%s'", filename );
o->torrent_id = torrent_id;
o->file_index = i;
o->used_at = tr_time( );
return o->fd;
}
/***
****
**** Sockets
****
***/
int
tr_fdSocketCreate( tr_session * session, int domain, int type )
{
int s = -1;
struct tr_fdInfo * gFd;
assert( tr_isSession( session ) );
ensureSessionFdInfoExists( session );
gFd = session->fdInfo;
if( gFd->peerCount < session->peerLimit )
if(( s = socket( domain, type, 0 )) < 0 )
if( sockerrno != EAFNOSUPPORT )
tr_err( _( "Couldn't create socket: %s" ), tr_strerror( sockerrno ) );
if( s > -1 )
++gFd->peerCount;
assert( gFd->peerCount >= 0 );
if( s >= 0 )
{
static bool buf_logged = false;
if( !buf_logged )
{
int i;
socklen_t size = sizeof( int );
buf_logged = true;
getsockopt( s, SOL_SOCKET, SO_SNDBUF, &i, &size );
tr_dbg( "SO_SNDBUF size is %d", i );
getsockopt( s, SOL_SOCKET, SO_RCVBUF, &i, &size );
tr_dbg( "SO_RCVBUF size is %d", i );
}
}
return s;
}
int
tr_fdSocketAccept( tr_session * s, int sockfd, tr_address * addr, tr_port * port )
{
int fd;
unsigned int len;
struct tr_fdInfo * gFd;
struct sockaddr_storage sock;
assert( tr_isSession( s ) );
assert( addr );
assert( port );
ensureSessionFdInfoExists( s );
gFd = s->fdInfo;
len = sizeof( struct sockaddr_storage );
fd = accept( sockfd, (struct sockaddr *) &sock, &len );
if( fd >= 0 )
{
if( ( gFd->peerCount < s->peerLimit )
&& tr_address_from_sockaddr_storage( addr, port, &sock ) )
{
++gFd->peerCount;
}
else
{
tr_netCloseSocket( fd );
fd = -1;
}
}
return fd;
}
void
tr_fdSocketClose( tr_session * session, int fd )
{
assert( tr_isSession( session ) );
if( session->fdInfo != NULL )
{
struct tr_fdInfo * gFd = session->fdInfo;
if( fd >= 0 )
{
tr_netCloseSocket( fd );
--gFd->peerCount;
}
assert( gFd->peerCount >= 0 );
}
}
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