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transmission/libtransmission/fdlimit.c

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/******************************************************************************
* $Id$
*
* Copyright (c) 2005-2006 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.
*****************************************************************************/
#include <assert.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <libgen.h> /* basename, dirname */
#include <fcntl.h>
#include <sys/queue.h> /* libevent needs this */
#include <sys/types.h> /* libevent needs this */
#include <event.h>
#include <evhttp.h>
#include <evutil.h>
#include "transmission.h"
#include "trcompat.h"
#include "net.h"
#include "platform.h"
#include "utils.h"
/**
***
**/
static void
myDebug( const char * file, int line, const char * fmt, ... )
{
FILE * fp = tr_getLog( );
if( fp != NULL )
{
va_list args;
char s[64];
struct evbuffer * buf = evbuffer_new( );
char * myfile = tr_strdup( file );
evbuffer_add_printf( buf, "[%s] ", tr_getLogTimeStr( s, sizeof(s) ) );
va_start( args, fmt );
evbuffer_add_vprintf( buf, fmt, args );
va_end( args );
evbuffer_add_printf( buf, " (%s:%d)\n", basename(myfile), line );
fwrite( EVBUFFER_DATA(buf), 1, EVBUFFER_LENGTH(buf), fp );
tr_free( myfile );
evbuffer_free( buf );
}
}
#define dbgmsg(fmt...) myDebug(__FILE__, __LINE__, ##fmt )
/**
***
**/
enum
{
TR_MAX_OPEN_FILES = 16, /* That is, real files, not sockets */
TR_RESERVED_FDS = 16 /* sockets reserved for tracker connections */
};
struct tr_openfile
{
unsigned int isCheckedOut : 1;
unsigned int isWritable : 1;
char filename[MAX_PATH_LENGTH];
int file;
uint64_t date;
};
struct tr_fd_s
{
int reserved;
int normal;
int normalMax;
tr_lock * lock;
tr_cond * cond;
struct tr_openfile open[TR_MAX_OPEN_FILES];
};
static struct tr_fd_s * gFd = NULL;
/***
****
**** Local Files
****
***/
static int
TrOpenFile( int i, const char * filename, int write )
{
struct tr_openfile * file = &gFd->open[i];
struct stat sb;
char * dir;
int flags;
tr_dbg( "Opening '%s' (%d)", filename, write );
/* create subfolders, if any */
dir = dirname( tr_strdup( filename ) );
if( write && tr_mkdirp( dir, 0700 ) ) {
free( dir );
return tr_ioErrorFromErrno( );
}
/* Make sure the parent folder exists */
if( stat( dir, &sb ) || !S_ISDIR( sb.st_mode ) ) {
free( dir );
return TR_ERROR_IO_PARENT;
}
errno = 0;
flags = 0;
#ifdef WIN32
flags |= O_BINARY;
#endif
flags |= write ? (O_RDWR | O_CREAT) : O_RDONLY;
file->file = open( filename, flags, 0666 );
free( dir );
if( write && ( file->file < 0 ) )
{
const int ret = tr_ioErrorFromErrno();
if( errno )
tr_err( "Couldn't open '%s': %s", filename, strerror(errno) );
else
tr_err( "Couldn't open '%s'", filename );
return ret;
}
return TR_OK;
}
static int
fileIsOpen( const struct tr_openfile * o )
{
return o->file >= 0;
}
static void
TrCloseFile( int i )
{
struct tr_openfile * file = &gFd->open[i];
assert( i >= 0 );
assert( i < TR_MAX_OPEN_FILES );
assert( fileIsOpen( file ) );
dbgmsg( "closing %s in slot %d writable %c",
file->filename, i, file->isWritable?'y':'n' );
close( file->file );
file->file = -1;
file->isCheckedOut = 0;
tr_condSignal( gFd->cond );
}
static int
fileIsCheckedOut( const struct tr_openfile * o )
{
return fileIsOpen(o) && o->isCheckedOut;
}
int
tr_fdFileOpen( const char * filename, int write )
{
int i, winner;
struct tr_openfile * o;
dbgmsg( "looking for file '%s', writable %c", filename, write?'y':'n' );
tr_lockLock( gFd->lock );
/* Is it already open? */
for( i=0; i<TR_MAX_OPEN_FILES; ++i )
{
o = &gFd->open[i];
if( !fileIsOpen( o ) )
continue;
if( strcmp( filename, o->filename ) )
continue;
if( fileIsCheckedOut( o ) ) {
dbgmsg( "found it! it's open, but checked out. waiting..." );
tr_condWait( gFd->cond, gFd->lock );
i = -1;
continue;
}
if( write && !o->isWritable ) {
dbgmsg( "found it! it's open and available, but isn't writable. closing..." );
TrCloseFile( i );
continue;
}
dbgmsg( "found it! it's ready for use!" );
winner = i;
goto done;
}
dbgmsg( "it's not already open. looking for an open slot or an old file." );
for( ;; )
{
uint64_t date = tr_date() + 1;
winner = -1;
for( i=0; i<TR_MAX_OPEN_FILES; ++i )
{
o = &gFd->open[i];
if( !fileIsOpen( o ) ) {
winner = i;
dbgmsg( "found an empty slot in %d", winner );
goto done;
}
if( o->date < date ) {
winner = i;
date = o->date;
}
}
if( winner >= 0 ) {
dbgmsg( "closing file '%s', slot #%d", gFd->open[winner].filename, winner );
TrCloseFile( winner );
goto done;
}
/* All used! Wait a bit and try again */
dbgmsg( "everything's full! waiting for someone else to finish something" );
tr_condWait( gFd->cond, gFd->lock );
}
done:
o = &gFd->open[winner];
if( !fileIsOpen( o ) )
{
const int ret = TrOpenFile( winner, filename, write );
if( ret ) {
tr_lockUnlock( gFd->lock );
return ret;
}
dbgmsg( "opened '%s' in slot %d, write %c", filename, winner, write?'y':'n' );
strlcpy( gFd->open[winner].filename, filename, MAX_PATH_LENGTH );
gFd->open[winner].isWritable = write;
}
dbgmsg( "checking out '%s' in slot %d", filename, winner );
gFd->open[winner].isCheckedOut = 1;
gFd->open[winner].date = tr_date();
tr_lockUnlock( gFd->lock );
return gFd->open[winner].file;
}
void
tr_fdFileRelease( int file )
{
int i;
tr_lockLock( gFd->lock );
for( i=0; i<TR_MAX_OPEN_FILES; ++i ) {
struct tr_openfile * o = &gFd->open[i];
if( o->file == file ) {
dbgmsg( "releasing file '%s' in slot #%d", o->filename, i );
if( o->isWritable )
fsync( o->file ); /* fflush */
o->isCheckedOut = 0;
break;
}
}
tr_condSignal( gFd->cond );
tr_lockUnlock( gFd->lock );
}
/***
****
**** Sockets
****
***/
struct tr_socket
{
int socket;
int priority;
};
/* Remember the priority of every socket we open, so that we can keep
* track of how many reserved file descriptors we are using */
static struct tr_socket * gSockets = NULL;
static int gSocketsSize = 0;
static int gSocketsCount = 0;
static void
SocketSetPriority( int s, int priority )
{
if( gSocketsSize <= gSocketsCount ) {
gSocketsSize += 64;
gSockets = tr_renew( struct tr_socket, gSockets, gSocketsSize );
}
gSockets[gSocketsCount].socket = s;
gSockets[gSocketsCount].priority = priority;
++gSocketsCount;
}
static int
SocketGetPriority( int s )
{
int i, ret;
for( i=0; i<gSocketsCount; ++i )
if( gSockets[i].socket == s )
break;
if( i >= gSocketsCount ) {
tr_err( "could not find that socket (%d)!", s );
return -1;
}
ret = gSockets[i].priority;
gSocketsCount--;
memmove( &gSockets[i], &gSockets[i+1],
( gSocketsCount - i ) * sizeof( struct tr_socket ) );
return ret;
}
int
tr_fdSocketCreate( int type, int priority )
{
int s = -1;
tr_lockLock( gFd->lock );
if( priority && gFd->reserved >= TR_RESERVED_FDS )
priority = FALSE;
if( priority || ( gFd->normal < gFd->normalMax ) )
if( ( s = socket( AF_INET, type, 0 ) ) < 0 )
tr_err( "Couldn't create socket (%s)", strerror( sockerrno ) );
if( s > -1 )
{
SocketSetPriority( s, priority );
if( priority )
gFd->reserved++;
else
gFd->normal++;
}
tr_lockUnlock( gFd->lock );
return s;
}
int
tr_fdSocketAccept( int b, struct in_addr * addr, tr_port_t * port )
{
int s = -1;
unsigned len;
struct sockaddr_in sock;
assert( addr != NULL );
assert( port != NULL );
tr_lockLock( gFd->lock );
if( gFd->normal < gFd->normalMax )
{
len = sizeof( sock );
s = accept( b, (struct sockaddr *) &sock, &len );
}
if( s > -1 )
{
SocketSetPriority( s, 0 );
*addr = sock.sin_addr;
*port = sock.sin_port;
gFd->normal++;
}
tr_lockUnlock( gFd->lock );
return s;
}
static void
socketClose( int fd )
{
#ifdef BEOS_NETSERVER
closesocket( fd );
#else
EVUTIL_CLOSESOCKET( fd );
#endif
}
void
tr_fdSocketClose( int s )
{
if( s >= 0 )
{
tr_lockLock( gFd->lock );
socketClose( s );
if( SocketGetPriority( s ) )
gFd->reserved--;
else
gFd->normal--;
tr_lockUnlock( gFd->lock );
}
}
/***
****
**** Startup / Shutdown
****
***/
void
tr_fdInit( void )
{
int i, j, s[4096];
assert( gFd == NULL );
gFd = tr_new0( struct tr_fd_s, 1 );
gFd->lock = tr_lockNew( );
gFd->cond = tr_condNew( );
/* count the max number of sockets we can use */
for( i=0; i<4096; ++i )
if( ( s[i] = socket( AF_INET, SOCK_STREAM, 0 ) ) < 0 )
break;
for( j=0; j<i; ++j )
socketClose( s[j] );
tr_dbg( "%d usable file descriptors", i );
/* set some fds aside for the UI or daemon to use */
gFd->normalMax = i - TR_RESERVED_FDS - 10;
for( i=0; i<TR_MAX_OPEN_FILES; ++i )
gFd->open[i].file = -1;
}
void
tr_fdClose( void )
{
int i = 0;
for( i=0; i<TR_MAX_OPEN_FILES; ++i )
if( fileIsOpen( &gFd->open[i] ) )
TrCloseFile( i );
tr_lockFree( gFd->lock );
tr_condFree( gFd->cond );
tr_free( gSockets );
tr_free( gFd );
}
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