/*
 * Server-side request handling
 *
 * Copyright (C) 1998 Alexandre Julliard
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#include "config.h"
#include "wine/port.h"

#include <assert.h>
#include <errno.h>
#include <fcntl.h>
#include <pwd.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
#include <string.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <sys/types.h>
#ifdef HAVE_SYS_SOCKET_H
# include <sys/socket.h>
#endif
#include <sys/uio.h>
#include <sys/un.h>
#include <unistd.h>

#include "winnt.h"
#include "winbase.h"
#include "wincon.h"
#include "thread.h"
#include "process.h"
#define WANT_REQUEST_HANDLERS
#include "request.h"

/* Some versions of glibc don't define this */
#ifndef SCM_RIGHTS
#define SCM_RIGHTS 1
#endif

 /* path names for server master Unix socket */
#define CONFDIR    "/.wine"        /* directory for Wine config relative to $HOME */
#define SERVERDIR  "wineserver-"   /* server socket directory (hostname appended) */
#define SOCKETNAME "socket"        /* name of the socket file */

struct master_socket
{
    struct object        obj;         /* object header */
    struct timeout_user *timeout;    /* timeout on last process exit */
};

static void master_socket_dump( struct object *obj, int verbose );
static void master_socket_poll_event( struct object *obj, int event );

static const struct object_ops master_socket_ops =
{
    sizeof(struct master_socket),  /* size */
    master_socket_dump,            /* dump */
    no_add_queue,                  /* add_queue */
    NULL,                          /* remove_queue */
    NULL,                          /* signaled */
    NULL,                          /* satisfied */
    NULL,                          /* get_poll_events */
    master_socket_poll_event,      /* poll_event */
    no_get_fd,                     /* get_fd */
    no_flush,                      /* flush */
    no_get_file_info,              /* get_file_info */
    NULL,                          /* queue_async */
    no_destroy                     /* destroy */
};


struct thread *current = NULL;  /* thread handling the current request */
unsigned int global_error = 0;  /* global error code for when no thread is current */
unsigned int server_start_ticks = 0;  /* tick count offset from server startup */

static struct master_socket *master_socket;  /* the master socket object */

/* socket communication static structures */
static struct iovec myiovec;
static struct msghdr msghdr;
#ifndef HAVE_MSGHDR_ACCRIGHTS
struct cmsg_fd
{
    int len;   /* sizeof structure */
    int level; /* SOL_SOCKET */
    int type;  /* SCM_RIGHTS */
    int fd;    /* fd to pass */
};
static struct cmsg_fd cmsg = { sizeof(cmsg), SOL_SOCKET, SCM_RIGHTS, -1 };
#endif  /* HAVE_MSGHDR_ACCRIGHTS */

/* complain about a protocol error and terminate the client connection */
void fatal_protocol_error( struct thread *thread, const char *err, ... )
{
    va_list args;

    va_start( args, err );
    fprintf( stderr, "Protocol error:%p: ", thread );
    vfprintf( stderr, err, args );
    va_end( args );
    thread->exit_code = 1;
    kill_thread( thread, 1 );
}

/* complain about a protocol error and terminate the client connection */
void fatal_protocol_perror( struct thread *thread, const char *err, ... )
{
    va_list args;

    va_start( args, err );
    fprintf( stderr, "Protocol error:%p: ", thread );
    vfprintf( stderr, err, args );
    perror( " " );
    va_end( args );
    thread->exit_code = 1;
    kill_thread( thread, 1 );
}

/* die on a fatal error */
void fatal_error( const char *err, ... )
{
    va_list args;

    va_start( args, err );
    fprintf( stderr, "wineserver: " );
    vfprintf( stderr, err, args );
    va_end( args );
    exit(1);
}

/* die on a fatal error */
void fatal_perror( const char *err, ... )
{
    va_list args;

    va_start( args, err );
    fprintf( stderr, "wineserver: " );
    vfprintf( stderr, err, args );
    perror( " " );
    va_end( args );
    exit(1);
}

/* allocate the reply data */
void *set_reply_data_size( size_t size )
{
    assert( size <= get_reply_max_size() );
    if (size && !(current->reply_data = mem_alloc( size ))) size = 0;
    current->reply_size = size;
    return current->reply_data;
}

/* write the remaining part of the reply */
void write_reply( struct thread *thread )
{
    int ret;

    if ((ret = write( thread->reply_fd,
                      (char *)thread->reply_data + thread->reply_size - thread->reply_towrite,
                      thread->reply_towrite )) >= 0)
    {
        if (!(thread->reply_towrite -= ret))
        {
            free( thread->reply_data );
            thread->reply_data = NULL;
            /* sent everything, can go back to waiting for requests */
            change_select_fd( &thread->obj, thread->request_fd, POLLIN );
        }
        return;
    }
    if (errno == EPIPE)
        kill_thread( thread, 0 );  /* normal death */
    else if (errno != EWOULDBLOCK && errno != EAGAIN)
        fatal_protocol_perror( thread, "reply write" );
}

/* send a reply to the current thread */
static void send_reply( union generic_reply *reply )
{
    int ret;

    if (!current->reply_size)
    {
        if ((ret = write( current->reply_fd, reply, sizeof(*reply) )) != sizeof(*reply)) goto error;
    }
    else
    {
        struct iovec vec[2];

        vec[0].iov_base = (void *)reply;
        vec[0].iov_len  = sizeof(*reply);
        vec[1].iov_base = current->reply_data;
        vec[1].iov_len  = current->reply_size;

        if ((ret = writev( current->reply_fd, vec, 2 )) < sizeof(*reply)) goto error;

        if ((current->reply_towrite = current->reply_size - (ret - sizeof(*reply))))
        {
            /* couldn't write it all, wait for POLLOUT */
            change_select_fd( &current->obj, current->reply_fd, POLLOUT );
            return;
        }
    }
    if (current->reply_data)
    {
        free( current->reply_data );
        current->reply_data = NULL;
    }
    return;

 error:
    if (ret >= 0)
        fatal_protocol_error( current, "partial write %d\n", ret );
    else if (errno == EPIPE)
        kill_thread( current, 0 );  /* normal death */
    else
        fatal_protocol_perror( current, "reply write" );
}

/* call a request handler */
static void call_req_handler( struct thread *thread )
{
    union generic_reply reply;
    enum request req = thread->req.request_header.req;

    current = thread;
    current->reply_size = 0;
    clear_error();
    memset( &reply, 0, sizeof(reply) );

    if (debug_level) trace_request();

    if (req < REQ_NB_REQUESTS)
    {
        req_handlers[req]( &current->req, &reply );
        if (current)
        {
            reply.reply_header.error = current->error;
            reply.reply_header.reply_size = current->reply_size;
            if (debug_level) trace_reply( req, &reply );
            send_reply( &reply );
        }
        current = NULL;
        return;
    }
    fatal_protocol_error( current, "bad request %d\n", req );
}

/* read a request from a thread */
void read_request( struct thread *thread )
{
    int ret;

    if (!thread->req_toread)  /* no pending request */
    {
        if ((ret = read( thread->obj.fd, &thread->req,
                         sizeof(thread->req) )) != sizeof(thread->req)) goto error;
        if (!(thread->req_toread = thread->req.request_header.request_size))
        {
            /* no data, handle request at once */
            call_req_handler( thread );
            return;
        }
        if (!(thread->req_data = malloc( thread->req_toread )))
            fatal_protocol_error( thread, "no memory for %d bytes request\n", thread->req_toread );
    }

    /* read the variable sized data */
    for (;;)
    {
        ret = read( thread->obj.fd, ((char *)thread->req_data +
                                     thread->req.request_header.request_size - thread->req_toread),
                    thread->req_toread );
        if (ret <= 0) break;
        if (!(thread->req_toread -= ret))
        {
            call_req_handler( thread );
            free( thread->req_data );
            thread->req_data = NULL;
            return;
        }
    }

error:
    if (!ret)  /* closed pipe */
        kill_thread( thread, 0 );
    else if (ret > 0)
        fatal_protocol_error( thread, "partial read %d\n", ret );
    else if (errno != EWOULDBLOCK && errno != EAGAIN)
        fatal_protocol_perror( thread, "read" );
}

/* receive a file descriptor on the process socket */
int receive_fd( struct process *process )
{
    struct send_fd data;
    int fd, ret;

#ifdef HAVE_MSGHDR_ACCRIGHTS
    msghdr.msg_accrightslen = sizeof(int);
    msghdr.msg_accrights = (void *)&fd;
#else  /* HAVE_MSGHDR_ACCRIGHTS */
    msghdr.msg_control    = &cmsg;
    msghdr.msg_controllen = sizeof(cmsg);
    cmsg.fd = -1;
#endif  /* HAVE_MSGHDR_ACCRIGHTS */

    myiovec.iov_base = (void *)&data;
    myiovec.iov_len  = sizeof(data);

    ret = recvmsg( process->obj.fd, &msghdr, 0 );
#ifndef HAVE_MSGHDR_ACCRIGHTS
    fd = cmsg.fd;
#endif

    if (ret == sizeof(data))
    {
        struct thread *thread;

        if (data.tid) thread = get_thread_from_id( data.tid );
        else thread = (struct thread *)grab_object( process->thread_list );

        if (!thread || thread->process != process)
        {
            if (debug_level)
                fprintf( stderr, "%08x: *fd* %d <- %d bad thread id\n",
                         (unsigned int)data.tid, data.fd, fd );
            close( fd );
        }
        else
        {
            if (debug_level)
                fprintf( stderr, "%08x: *fd* %d <- %d\n",
                         (unsigned int)thread, data.fd, fd );
            thread_add_inflight_fd( thread, data.fd, fd );
        }
        if (thread) release_object( thread );
        return 0;
    }

    if (ret >= 0)
    {
        if (ret > 0)
            fprintf( stderr, "Protocol error: process %p: partial recvmsg %d for fd\n",
                     process, ret );
        kill_process( process, NULL, 1 );
    }
    else
    {
        if (errno != EWOULDBLOCK && errno != EAGAIN)
        {
            fprintf( stderr, "Protocol error: process %p: ", process );
            perror( "recvmsg" );
            kill_process( process, NULL, 1 );
        }
    }
    return -1;
}

/* send an fd to a client */
int send_client_fd( struct process *process, int fd, obj_handle_t handle )
{
    int ret;

    if (debug_level)
        fprintf( stderr, "%08x: *fd* %d -> %d\n", (unsigned int)current, handle, fd );

#ifdef HAVE_MSGHDR_ACCRIGHTS
    msghdr.msg_accrightslen = sizeof(fd);
    msghdr.msg_accrights = (void *)&fd;
#else  /* HAVE_MSGHDR_ACCRIGHTS */
    msghdr.msg_control    = &cmsg;
    msghdr.msg_controllen = sizeof(cmsg);
    cmsg.fd = fd;
#endif  /* HAVE_MSGHDR_ACCRIGHTS */

    myiovec.iov_base = (void *)&handle;
    myiovec.iov_len  = sizeof(handle);

    ret = sendmsg( process->obj.fd, &msghdr, 0 );

    if (ret == sizeof(handle)) return 0;

    if (ret >= 0)
    {
        if (ret > 0)
            fprintf( stderr, "Protocol error: process %p: partial sendmsg %d\n", process, ret );
        kill_process( process, NULL, 1 );
    }
    else
    {
        fprintf( stderr, "Protocol error: process %p: ", process );
        perror( "sendmsg" );
        kill_process( process, NULL, 1 );
    }
    return -1;
}

/* get current tick count to return to client */
unsigned int get_tick_count(void)
{
    struct timeval t;
    gettimeofday( &t, NULL );
    return (t.tv_sec * 1000) + (t.tv_usec / 1000) - server_start_ticks;
}

static void master_socket_dump( struct object *obj, int verbose )
{
    struct master_socket *sock = (struct master_socket *)obj;
    assert( obj->ops == &master_socket_ops );
    fprintf( stderr, "Master socket fd=%d\n", sock->obj.fd );
}

/* handle a socket event */
static void master_socket_poll_event( struct object *obj, int event )
{
    struct master_socket *sock = (struct master_socket *)obj;
    assert( obj->ops == &master_socket_ops );

    assert( sock == master_socket );  /* there is only one master socket */

    if (event & (POLLERR | POLLHUP))
    {
        /* this is not supposed to happen */
        fprintf( stderr, "wineserver: Error on master socket\n" );
        release_object( obj );
    }
    else if (event & POLLIN)
    {
        struct sockaddr_un dummy;
        int len = sizeof(dummy);
        int client = accept( master_socket->obj.fd, (struct sockaddr *) &dummy, &len );
        if (client == -1) return;
        if (sock->timeout)
        {
            remove_timeout_user( sock->timeout );
            sock->timeout = NULL;
        }
        fcntl( client, F_SETFL, O_NONBLOCK );
        create_process( client );
    }
}

/* remove the socket upon exit */
static void socket_cleanup(void)
{
    static int do_it_once;
    if (!do_it_once++) unlink( SOCKETNAME );
}

/* return the configuration directory ($WINEPREFIX or $HOME/.wine) */
const char *get_config_dir(void)
{
    static char *confdir;
    if (!confdir)
    {
        const char *prefix = getenv( "WINEPREFIX" );
        if (prefix)
        {
            int len = strlen(prefix);
            if (!(confdir = strdup( prefix ))) fatal_error( "out of memory\n" );
            if (len > 1 && confdir[len-1] == '/') confdir[len-1] = 0;
        }
        else
        {
            const char *home = getenv( "HOME" );
            if (!home)
            {
                struct passwd *pwd = getpwuid( getuid() );
                if (!pwd) fatal_error( "could not find your home directory\n" );
                home = pwd->pw_dir;
            }
            if (!(confdir = malloc( strlen(home) + strlen(CONFDIR) + 1 )))
                fatal_error( "out of memory\n" );
            strcpy( confdir, home );
            strcat( confdir, CONFDIR );
        }
    }
    return confdir;
}

/* create the server directory and chdir to it */
static void create_server_dir(void)
{
    char hostname[64];
    char *serverdir;
    const char *confdir = get_config_dir();
    struct stat st;

    if (gethostname( hostname, sizeof(hostname) ) == -1) fatal_perror( "gethostname" );

    if (!(serverdir = malloc( strlen(SERVERDIR) + strlen(hostname) + 1 )))
        fatal_error( "out of memory\n" );

    if (chdir( confdir ) == -1) fatal_perror( "chdir %s", confdir );

    strcpy( serverdir, SERVERDIR );
    strcat( serverdir, hostname );

    if (chdir( serverdir ) == -1)
    {
        if (errno != ENOENT) fatal_perror( "chdir %s", serverdir );
        if (mkdir( serverdir, 0700 ) == -1) fatal_perror( "mkdir %s", serverdir );
        if (chdir( serverdir ) == -1) fatal_perror( "chdir %s", serverdir );
    }
    if (stat( ".", &st ) == -1) fatal_perror( "stat %s", serverdir );
    if (!S_ISDIR(st.st_mode)) fatal_error( "%s is not a directory\n", serverdir );
    if (st.st_uid != getuid()) fatal_error( "%s is not owned by you\n", serverdir );
    if (st.st_mode & 077) fatal_error( "%s must not be accessible by other users\n", serverdir );
}

/* open the master server socket and start waiting for new clients */
void open_master_socket(void)
{
    struct sockaddr_un addr;
    int fd, slen;

    /* make sure no request is larger than the maximum size */
    assert( sizeof(union generic_request) == sizeof(struct request_max_size) );
    assert( sizeof(union generic_reply) == sizeof(struct request_max_size) );

    create_server_dir();
    if ((fd = socket( AF_UNIX, SOCK_STREAM, 0 )) == -1) fatal_perror( "socket" );
    addr.sun_family = AF_UNIX;
    strcpy( addr.sun_path, SOCKETNAME );
    slen = sizeof(addr) - sizeof(addr.sun_path) + strlen(addr.sun_path) + 1;
#ifdef HAVE_SOCKADDR_SUN_LEN
    addr.sun_len = slen;
#endif
    if (bind( fd, (struct sockaddr *)&addr, slen ) == -1)
    {
        if ((errno == EEXIST) || (errno == EADDRINUSE))
            exit(0);  /* pretend we succeeded to start */
        else
            fatal_perror( "bind" );
    }
    atexit( socket_cleanup );

    chmod( SOCKETNAME, 0600 );  /* make sure no other user can connect */
    if (listen( fd, 5 ) == -1) fatal_perror( "listen" );

    if (!(master_socket = alloc_object( &master_socket_ops, fd )))
        fatal_error( "out of memory\n" );
    master_socket->timeout = NULL;
    set_select_events( &master_socket->obj, POLLIN );

    /* setup msghdr structure constant fields */
    msghdr.msg_name    = NULL;
    msghdr.msg_namelen = 0;
    msghdr.msg_iov     = &myiovec;
    msghdr.msg_iovlen  = 1;

    /* init startup ticks */
    server_start_ticks = get_tick_count();

    /* go in the background */
    switch(fork())
    {
    case -1:
        fatal_perror( "fork" );
    case 0:
        setsid();
        break;
    default:
        _exit(0);  /* do not call atexit functions */
    }
}

/* master socket timer expiration handler */
static void close_socket_timeout( void *arg )
{
    /* if a new client is waiting, we keep on running */
    if (!check_select_events( master_socket->obj.fd, POLLIN ))
        release_object( master_socket );
}

/* close the master socket and stop waiting for new clients */
void close_master_socket(void)
{
    struct timeval when;

    if (master_socket_timeout == -1) return;  /* just keep running forever */

    if (master_socket_timeout)
    {
        gettimeofday( &when, 0 );
        add_timeout( &when, master_socket_timeout * 1000 );
        master_socket->timeout = add_timeout_user( &when, close_socket_timeout, NULL );
    }
    else close_socket_timeout( NULL );  /* close it right away */
}

/* lock/unlock the master socket to stop accepting new clients */
void lock_master_socket( int locked )
{
    set_select_events( &master_socket->obj, locked ? 0 : POLLIN );
}