/******************************************************************************
 * $Id$
 *
 * Copyright (c) 2005 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.
 *****************************************************************************/

#ifdef SYS_BEOS
  #include <fs_info.h>
  #include <FindDirectory.h>
#endif
#include <sys/types.h>
#include <dirent.h>

#include "transmission.h"

static void
tr_migrateResume( const char *oldDirectory, const char *newDirectory )
{
    DIR * dirh;
    struct dirent * dirp;
    char oldFile[MAX_PATH_LENGTH];
    char newFile[MAX_PATH_LENGTH];

    if( ( dirh = opendir( oldDirectory ) ) )
    {
        while( ( dirp = readdir( dirh ) ) )
        {
            if( strncmp( "resume.", dirp->d_name, 7 ) )
            {
                continue;
            }
            snprintf( oldFile, MAX_PATH_LENGTH, "%s/%s",
                      oldDirectory, dirp->d_name );
            snprintf( newFile, MAX_PATH_LENGTH, "%s/%s",
                      newDirectory, dirp->d_name );
            rename( oldFile, newFile );
        }

        closedir( dirh );
    }
}

char * tr_getPrefsDirectory()
{
    static char prefsDirectory[MAX_PATH_LENGTH];
    static int  init = 0;

    if( init )
    {
        return prefsDirectory;
    }

#ifdef SYS_BEOS
	find_directory( B_USER_SETTINGS_DIRECTORY, dev_for_path("/boot"),
	                true, prefsDirectory, MAX_PATH_LENGTH );
	strcat( prefsDirectory, "/Transmission" );
#elif defined( SYS_DARWIN )
    snprintf( prefsDirectory, MAX_PATH_LENGTH,
              "%s/Library/Caches/Transmission", getenv( "HOME" ) );
#elif defined(__AMIGAOS4__)
    snprintf( prefsDirectory, MAX_PATH_LENGTH, "PROGDIR:.transmission" );
#else
    snprintf( prefsDirectory, MAX_PATH_LENGTH, "%s/.transmission",
              getenv( "HOME" ) );
#endif

    tr_mkdir( prefsDirectory );
    init = 1;

#ifdef SYS_DARWIN
    char oldDirectory[MAX_PATH_LENGTH];
    snprintf( oldDirectory, MAX_PATH_LENGTH, "%s/.transmission",
              getenv( "HOME" ) );
    tr_migrateResume( oldDirectory, prefsDirectory );
    rmdir( oldDirectory );
#endif

    return prefsDirectory;
}

char * tr_getCacheDirectory()
{
    static char cacheDirectory[MAX_PATH_LENGTH];
    static int  init = 0;

    if( init )
    {
        return cacheDirectory;
    }

#ifdef SYS_BEOS
    /* XXX hey Bryan, is this fine with you? */
    snprintf( cacheDirectory, MAX_PATH_LENGTH, "%s/Cache",
              tr_getPrefsDirectory() );
#elif defined( SYS_DARWIN )
    snprintf( cacheDirectory, MAX_PATH_LENGTH, "%s",
              tr_getPrefsDirectory() );
#else
    snprintf( cacheDirectory, MAX_PATH_LENGTH, "%s/cache",
              tr_getPrefsDirectory() );
#endif

    tr_mkdir( cacheDirectory );
    init = 1;

    if( strcmp( tr_getPrefsDirectory(), cacheDirectory ) )
    {
        tr_migrateResume( tr_getPrefsDirectory(), cacheDirectory );
    }

    return cacheDirectory;
}

char * tr_getTorrentsDirectory()
{
    static char torrentsDirectory[MAX_PATH_LENGTH];
    static int  init = 0;

    if( init )
    {
        return torrentsDirectory;
    }

#ifdef SYS_BEOS
    /* XXX hey Bryan, is this fine with you? */
    snprintf( torrentsDirectory, MAX_PATH_LENGTH, "%s/Torrents",
              tr_getPrefsDirectory() );
#elif defined( SYS_DARWIN )
    snprintf( torrentsDirectory, MAX_PATH_LENGTH,
              "%s/Library/Application Support/Transmission/Torrents",
              getenv( "HOME" ) );
#else
    snprintf( torrentsDirectory, MAX_PATH_LENGTH, "%s/torrents",
              tr_getPrefsDirectory() );
#endif

    tr_mkdir( torrentsDirectory );
    init = 1;

    return torrentsDirectory;
}

void tr_threadCreate( tr_thread_t * t, void (*func)(void *), void * arg )
{
#ifdef SYS_BEOS
    *t = spawn_thread( (void *) func, "torrent-tx", B_NORMAL_PRIORITY, arg );
    resume_thread( *t );
#else
    pthread_create( t, NULL, (void *) func, arg );
#endif
}

void tr_threadJoin( tr_thread_t * t )
{
#ifdef SYS_BEOS
    long exit;
    wait_for_thread( *t, &exit );
#else
    pthread_join( *t, NULL );
#endif
}

void tr_lockInit( tr_lock_t * l )
{
#ifdef SYS_BEOS
    *l = create_sem( 1, "" );
#else
    pthread_mutex_init( l, NULL );
#endif
}

void tr_lockClose( tr_lock_t * l )
{
#ifdef SYS_BEOS
    delete_sem( *l );
#else
    pthread_mutex_destroy( l );
#endif
}

#if defined( BSD )

#include <sys/sysctl.h>
#include <net/route.h>

static uint8_t *
getroute( int * buflen );
static int
parseroutes( uint8_t * buf, int len, struct in_addr * addr );

int
tr_getDefaultRoute( struct in_addr * addr )
{
    uint8_t * buf;
    int len;

    buf = getroute( &len );
    if( NULL == buf )
    {
        tr_err( "failed to get default route (BSD)" );
        return 1;
    }

    len = parseroutes( buf, len, addr );
    free( buf );

    return len;
}

#ifndef SA_SIZE
#define ROUNDUP( a, size ) \
    ( ( (a) & ( (size) - 1 ) ) ? ( 1 + ( (a) | ( (size) - 1 ) ) ) : (a) )
#define SA_SIZE( sap ) \
    ( sap->sa_len ? ROUNDUP( (sap)->sa_len, sizeof( u_long ) ) : \
                    sizeof( u_long ) )
#endif /* !SA_SIZE */
#define NEXT_SA( sap ) \
    (struct sockaddr *) ( (caddr_t) (sap) + ( SA_SIZE( (sap) ) ) )

static uint8_t *
getroute( int * buflen )
{
    int     mib[6];
    size_t  len;
    uint8_t * buf;

    mib[0] = CTL_NET;
    mib[1] = PF_ROUTE;
    mib[2] = 0;
    mib[3] = AF_INET;
    mib[4] = NET_RT_FLAGS;
    mib[5] = RTF_GATEWAY;

    if( sysctl( mib, 6, NULL, &len, NULL, 0 ) )
    {
        if( ENOENT != errno )
        {
            tr_err( "sysctl net.route.0.inet.flags.gateway failed (%s)",
                    strerror( errno ) );
        }
        *buflen = 0;
        return NULL;
    }

    buf = malloc( len );
    if( NULL == buf )
    {
        *buflen = 0;
        return NULL;
    }

    if( sysctl( mib, 6, buf, &len, NULL, 0 ) )
    {
        tr_err( "sysctl net.route.0.inet.flags.gateway failed (%s)",
                strerror( errno ) );
        free( buf );
        *buflen = 0;
        return NULL;
    }

    *buflen = len;

    return buf;
}

static int
parseroutes( uint8_t * buf, int len, struct in_addr * addr )
{
    uint8_t            * end;
    struct rt_msghdr   * rtm;
    struct sockaddr    * sa;
    struct sockaddr_in * sin;
    int                  ii;
    struct in_addr       dest, gw;

    end = buf + len;
    while( end > buf + sizeof( *rtm ) )
    {
        rtm = (struct rt_msghdr *) buf;
        buf += rtm->rtm_msglen;
        if( end >= buf )
        {
            dest.s_addr = INADDR_NONE;
            gw.s_addr   = INADDR_NONE;
            sa = (struct sockaddr *) ( rtm + 1 );

            for( ii = 0; ii < RTAX_MAX && (uint8_t *) sa < buf; ii++ )
            {
                if( buf < (uint8_t *) NEXT_SA( sa ) )
                {
                    break;
                }

                if( rtm->rtm_addrs & ( 1 << ii ) )
                {
                    if( AF_INET == sa->sa_family )
                    {
                        sin = (struct sockaddr_in *) sa;
                        switch( ii )
                        {
                            case RTAX_DST:
                                dest = sin->sin_addr;
                                break;
                            case RTAX_GATEWAY:
                                gw = sin->sin_addr;
                                break;
                        }
                    }
                    sa = NEXT_SA( sa );
                }
            }

            if( INADDR_ANY == dest.s_addr && INADDR_NONE != gw.s_addr )
            {
                *addr = gw;
                return 0;
            }
        }
    }

    return 1;
}

#elif defined( linux ) || defined( __linux ) || defined( __linux__ )

#include <linux/types.h>
#include <linux/netlink.h>
#include <linux/rtnetlink.h>

#define SEQNUM 195909

static int
getsock( void );
static uint8_t *
getroute( int fd, unsigned int * buflen );
static int
parseroutes( uint8_t * buf, unsigned int len, struct in_addr * addr );

int
tr_getDefaultRoute( struct in_addr * addr )
{
    int fd, ret;
    unsigned int len;
    uint8_t * buf;

    ret = 1;
    fd = getsock();
    if( 0 <= fd )
    {
        while( ret )
        {
            buf = getroute( fd, &len );
            if( NULL == buf )
            {
                break;
            }
            ret = parseroutes( buf, len, addr );
            free( buf );
        }
        close( fd );
    }

    if( ret )
    {
        tr_err( "failed to get default route (Linux)" );
    }

    return ret;
}

static int
getsock( void )
{
    int fd, flags;
    struct
    {
        struct nlmsghdr nlh;
        struct rtgenmsg rtg;
    } req;
    struct sockaddr_nl snl;

    fd = socket( PF_NETLINK, SOCK_DGRAM, NETLINK_ROUTE );
    if( 0 > fd )
    {
        tr_err( "failed to create routing socket (%s)", strerror( errno ) );
        return -1;
    }

    flags = fcntl( fd, F_GETFL );
    if( 0 > flags || 0 > fcntl( fd, F_SETFL, O_NONBLOCK | flags ) )
    {
        tr_err( "failed to set socket nonblocking (%s)", strerror( errno ) );
        close( fd );
        return -1;
    }

    bzero( &snl, sizeof( snl ) );
    snl.nl_family = AF_NETLINK;

    bzero( &req, sizeof( req ) );
    req.nlh.nlmsg_len = NLMSG_LENGTH( sizeof( req.rtg ) );
    req.nlh.nlmsg_type = RTM_GETROUTE;
    req.nlh.nlmsg_flags = NLM_F_REQUEST | NLM_F_DUMP;
    req.nlh.nlmsg_seq = SEQNUM;
    req.nlh.nlmsg_pid = 0;
    req.rtg.rtgen_family = AF_INET;

    if( 0 > sendto( fd, &req, sizeof( req ), 0,
                    (struct sockaddr *) &snl, sizeof( snl ) ) )
    {
        tr_err( "failed to write to routing socket (%s)", strerror( errno ) );
        close( fd );
        return -1;
    }

    return fd;
}

static uint8_t *
getroute( int fd, unsigned int * buflen )
{
    void             * buf;
    unsigned int       len;
    ssize_t            res;
    struct sockaddr_nl snl;
    socklen_t          slen;

    len = 8192;
    buf = calloc( 1, len );
    if( NULL == buf )
    {
        *buflen = 0;
        return NULL;
    }

    for( ;; )
    {
        bzero( &snl, sizeof( snl ) );
        slen = sizeof( snl );
        res = recvfrom( fd, buf, len, 0, (struct sockaddr *) &snl, &slen );
        if( 0 > res )
        {
            if( EAGAIN != errno )
            {
                tr_err( "failed to read from routing socket (%s)",
                        strerror( errno ) );
            }
            free( buf );
            *buflen = 0;
            return NULL;
        }
        if( slen < sizeof( snl ) || AF_NETLINK != snl.nl_family )
        {
            tr_err( "bad address" );
            free( buf );
            *buflen = 0;
            return NULL;
        }

        if( 0 == snl.nl_pid )
        {
            break;
        }
    }

    *buflen = res;

    return buf;
}

static int
parseroutes( uint8_t * buf, unsigned int len, struct in_addr * addr )
{
    struct nlmsghdr * nlm;
    struct nlmsgerr * nle;
    struct rtmsg    * rtm;
    struct rtattr   * rta;
    int               rtalen;
    struct in_addr    gw, dst;

    nlm = ( struct nlmsghdr * ) buf;
    while( NLMSG_OK( nlm, len ) )
    {
        gw.s_addr = INADDR_ANY;
        dst.s_addr = INADDR_ANY;
        if( NLMSG_ERROR == nlm->nlmsg_type )
        {
            nle = (struct nlmsgerr *) NLMSG_DATA( nlm );
            if( NLMSG_LENGTH( NLMSG_ALIGN( sizeof( struct nlmsgerr ) ) ) >
                nlm->nlmsg_len )
            {
                tr_err( "truncated netlink error" );
            }
            else
            {
                tr_err( "netlink error (%s)", strerror( nle->error ) );
            }
            return 1;
        }
        else if( RTM_NEWROUTE == nlm->nlmsg_type && SEQNUM == nlm->nlmsg_seq &&
                 getpid() == (pid_t) nlm->nlmsg_pid &&
                 NLMSG_LENGTH( sizeof( struct rtmsg ) ) <= nlm->nlmsg_len )
        {
            rtm = NLMSG_DATA( nlm );
            rta = RTM_RTA( rtm );
            rtalen = RTM_PAYLOAD( nlm );

            while( RTA_OK( rta, rtalen ) )
            {
                if( sizeof( struct in_addr ) <= RTA_PAYLOAD( rta ) )
                {
                    switch( rta->rta_type )
                    {
                        case RTA_GATEWAY:
                            memcpy( &gw, RTA_DATA( rta ), sizeof( gw ) );
                            break;
                        case RTA_DST:
                            memcpy( &dst, RTA_DATA( rta ), sizeof( dst ) );
                            break;
                    }
                }
                rta = RTA_NEXT( rta, rtalen );
            }
        }

        if( INADDR_NONE != gw.s_addr && INADDR_ANY != gw.s_addr &&
            INADDR_ANY == dst.s_addr )
        {
            *addr = gw;
            return 0;
        }

        nlm = NLMSG_NEXT( nlm, len );
    }

    return 1;
}

#else /* not BSD or Linux */

int
tr_getDefaultRoute( struct in_addr * addr UNUSED )
{
    tr_inf( "don't know how to get default route on this platform" );
    return 1;
}

#endif