/*
 * Wine server communication
 *
 * 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., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
 */

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

#include <assert.h>
#include <ctype.h>
#include <dirent.h>
#include <errno.h>
#include <fcntl.h>
#include <signal.h>
#include <stdarg.h>
#include <stdio.h>
#include <string.h>
#include <sys/types.h>
#ifdef HAVE_SYS_SOCKET_H
# include <sys/socket.h>
#endif
#ifdef HAVE_SYS_WAIT_H
#include <sys/wait.h>
#endif
#ifdef HAVE_SYS_UN_H
#include <sys/un.h>
#endif
#ifdef HAVE_SYS_MMAN_H
#include <sys/mman.h>
#endif
#ifdef HAVE_SYS_STAT_H
# include <sys/stat.h>
#endif
#ifdef HAVE_SYS_UIO_H
#include <sys/uio.h>
#endif
#ifdef HAVE_UNISTD_H
# include <unistd.h>
#endif

#include "ntstatus.h"
#define WIN32_NO_STATUS
#include "wine/library.h"
#include "wine/pthread.h"
#include "wine/server.h"
#include "wine/debug.h"
#include "ntdll_misc.h"

WINE_DEFAULT_DEBUG_CHANNEL(server);

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

#define SOCKETNAME "socket"        /* name of the socket file */
#define LOCKNAME   "lock"          /* name of the lock file */

#ifndef HAVE_STRUCT_MSGHDR_MSG_ACCRIGHTS
/* data structure used to pass an fd with sendmsg/recvmsg */
struct cmsg_fd
{
    struct
    {
        size_t len;   /* size of structure */
        int    level; /* SOL_SOCKET */
        int    type;  /* SCM_RIGHTS */
    } header;
    int fd;          /* fd to pass */
};
#endif  /* HAVE_STRUCT_MSGHDR_MSG_ACCRIGHTS */

abs_time_t server_start_time = { 0, 0 };  /* time of server startup */

extern struct wine_pthread_functions pthread_functions;

static sigset_t block_set;  /* signals to block during server calls */
static int fd_socket = -1;  /* socket to exchange file descriptors with the server */

static RTL_CRITICAL_SECTION fd_cache_section;
static RTL_CRITICAL_SECTION_DEBUG critsect_debug =
{
    0, 0, &fd_cache_section,
    { &critsect_debug.ProcessLocksList, &critsect_debug.ProcessLocksList },
      0, 0, { (DWORD_PTR)(__FILE__ ": fd_cache_section") }
};
static RTL_CRITICAL_SECTION fd_cache_section = { &critsect_debug, -1, 0, 0, 0, 0 };


#ifdef __GNUC__
static void fatal_error( const char *err, ... ) __attribute__((noreturn, format(printf,1,2)));
static void fatal_perror( const char *err, ... ) __attribute__((noreturn, format(printf,1,2)));
static void server_connect_error( const char *serverdir ) __attribute__((noreturn));
#endif

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

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

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

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


/***********************************************************************
 *           server_exit_thread
 */
void server_exit_thread( int status )
{
    struct wine_pthread_thread_info info;
    SIZE_T size;
    int fds[4];

    RtlAcquirePebLock();
    RemoveEntryList( &NtCurrentTeb()->TlsLinks );
    RtlReleasePebLock();

    info.stack_base  = NtCurrentTeb()->DeallocationStack;
    info.teb_base    = NtCurrentTeb();
    info.teb_sel     = wine_get_fs();
    info.exit_status = status;

    fds[0] = ntdll_get_thread_data()->wait_fd[0];
    fds[1] = ntdll_get_thread_data()->wait_fd[1];
    fds[2] = ntdll_get_thread_data()->reply_fd;
    fds[3] = ntdll_get_thread_data()->request_fd;
    pthread_functions.sigprocmask( SIG_BLOCK, &block_set, NULL );

    size = 0;
    NtFreeVirtualMemory( GetCurrentProcess(), &info.stack_base, &size, MEM_RELEASE | MEM_SYSTEM );
    info.stack_size = size;

    size = 0;
    NtFreeVirtualMemory( GetCurrentProcess(), &info.teb_base, &size, MEM_RELEASE | MEM_SYSTEM );
    info.teb_size = size;

    close( fds[0] );
    close( fds[1] );
    close( fds[2] );
    close( fds[3] );
    pthread_functions.exit_thread( &info );
}


/***********************************************************************
 *           server_abort_thread
 */
void server_abort_thread( int status )
{
    pthread_functions.sigprocmask( SIG_BLOCK, &block_set, NULL );
    close( ntdll_get_thread_data()->wait_fd[0] );
    close( ntdll_get_thread_data()->wait_fd[1] );
    close( ntdll_get_thread_data()->reply_fd );
    close( ntdll_get_thread_data()->request_fd );
    pthread_functions.abort_thread( status );
}


/***********************************************************************
 *           server_protocol_error
 */
void server_protocol_error( const char *err, ... )
{
    va_list args;

    va_start( args, err );
    fprintf( stderr, "wine client error:%x: ", GetCurrentThreadId() );
    vfprintf( stderr, err, args );
    va_end( args );
    server_abort_thread(1);
}


/***********************************************************************
 *           server_protocol_perror
 */
void server_protocol_perror( const char *err )
{
    fprintf( stderr, "wine client error:%x: ", GetCurrentThreadId() );
    perror( err );
    server_abort_thread(1);
}


/***********************************************************************
 *           send_request
 *
 * Send a request to the server.
 */
static void send_request( const struct __server_request_info *req )
{
    unsigned int i;
    int ret;

    if (!req->u.req.request_header.request_size)
    {
        if ((ret = write( ntdll_get_thread_data()->request_fd, &req->u.req,
                          sizeof(req->u.req) )) == sizeof(req->u.req)) return;

    }
    else
    {
        struct iovec vec[__SERVER_MAX_DATA+1];

        vec[0].iov_base = (void *)&req->u.req;
        vec[0].iov_len = sizeof(req->u.req);
        for (i = 0; i < req->data_count; i++)
        {
            vec[i+1].iov_base = (void *)req->data[i].ptr;
            vec[i+1].iov_len = req->data[i].size;
        }
        if ((ret = writev( ntdll_get_thread_data()->request_fd, vec, i+1 )) ==
            req->u.req.request_header.request_size + sizeof(req->u.req)) return;
    }

    if (ret >= 0) server_protocol_error( "partial write %d\n", ret );
    if (errno == EPIPE) server_abort_thread(0);
    server_protocol_perror( "write" );
}


/***********************************************************************
 *           read_reply_data
 *
 * Read data from the reply buffer; helper for wait_reply.
 */
static void read_reply_data( void *buffer, size_t size )
{
    int ret;

    for (;;)
    {
        if ((ret = read( ntdll_get_thread_data()->reply_fd, buffer, size )) > 0)
        {
            if (!(size -= ret)) return;
            buffer = (char *)buffer + ret;
            continue;
        }
        if (!ret) break;
        if (errno == EINTR) continue;
        if (errno == EPIPE) break;
        server_protocol_perror("read");
    }
    /* the server closed the connection; time to die... */
    server_abort_thread(0);
}


/***********************************************************************
 *           wait_reply
 *
 * Wait for a reply from the server.
 */
inline static void wait_reply( struct __server_request_info *req )
{
    read_reply_data( &req->u.reply, sizeof(req->u.reply) );
    if (req->u.reply.reply_header.reply_size)
        read_reply_data( req->reply_data, req->u.reply.reply_header.reply_size );
}


/***********************************************************************
 *           wine_server_call (NTDLL.@)
 *
 * Perform a server call.
 *
 * PARAMS
 *     req_ptr [I/O] Function dependent data
 *
 * RETURNS
 *     Depends on server function being called, but usually an NTSTATUS code.
 *
 * NOTES
 *     Use the SERVER_START_REQ and SERVER_END_REQ to help you fill out the
 *     server request structure for the particular call. E.g:
 *|     SERVER_START_REQ( event_op )
 *|     {
 *|         req->handle = handle;
 *|         req->op     = SET_EVENT;
 *|         ret = wine_server_call( req );
 *|     }
 *|     SERVER_END_REQ;
 */
unsigned int wine_server_call( void *req_ptr )
{
    struct __server_request_info * const req = req_ptr;
    sigset_t old_set;

    pthread_functions.sigprocmask( SIG_BLOCK, &block_set, &old_set );
    send_request( req );
    wait_reply( req );
    pthread_functions.sigprocmask( SIG_SETMASK, &old_set, NULL );
    return req->u.reply.reply_header.error;
}


/***********************************************************************
 *           wine_server_send_fd   (NTDLL.@)
 *
 * Send a file descriptor to the server.
 *
 * PARAMS
 *     fd [I] file descriptor to send
 *
 * RETURNS
 *     nothing
 */
void wine_server_send_fd( int fd )
{
#ifndef HAVE_STRUCT_MSGHDR_MSG_ACCRIGHTS
    struct cmsg_fd cmsg;
#endif
    struct send_fd data;
    struct msghdr msghdr;
    struct iovec vec;
    int ret;

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

    msghdr.msg_name    = NULL;
    msghdr.msg_namelen = 0;
    msghdr.msg_iov     = &vec;
    msghdr.msg_iovlen  = 1;

#ifdef HAVE_STRUCT_MSGHDR_MSG_ACCRIGHTS
    msghdr.msg_accrights    = (void *)&fd;
    msghdr.msg_accrightslen = sizeof(fd);
#else  /* HAVE_STRUCT_MSGHDR_MSG_ACCRIGHTS */
    cmsg.header.len   = sizeof(cmsg.header) + sizeof(fd);
    cmsg.header.level = SOL_SOCKET;
    cmsg.header.type  = SCM_RIGHTS;
    cmsg.fd           = fd;
    msghdr.msg_control    = &cmsg;
    msghdr.msg_controllen = sizeof(cmsg.header) + sizeof(fd);
    msghdr.msg_flags      = 0;
#endif  /* HAVE_STRUCT_MSGHDR_MSG_ACCRIGHTS */

    data.tid = GetCurrentThreadId();
    data.fd  = fd;

    for (;;)
    {
        if ((ret = sendmsg( fd_socket, &msghdr, 0 )) == sizeof(data)) return;
        if (ret >= 0) server_protocol_error( "partial write %d\n", ret );
        if (errno == EINTR) continue;
        if (errno == EPIPE) server_abort_thread(0);
        server_protocol_perror( "sendmsg" );
    }
}


/***********************************************************************
 *           receive_fd
 *
 * Receive a file descriptor passed from the server.
 */
static int receive_fd( obj_handle_t *handle )
{
    struct iovec vec;
    int ret, fd;

#ifdef HAVE_STRUCT_MSGHDR_MSG_ACCRIGHTS
    struct msghdr msghdr;

    fd = -1;
    msghdr.msg_accrights    = (void *)&fd;
    msghdr.msg_accrightslen = sizeof(fd);
#else  /* HAVE_STRUCT_MSGHDR_MSG_ACCRIGHTS */
    struct msghdr msghdr;
    struct cmsg_fd cmsg;

    cmsg.header.len   = sizeof(cmsg.header) + sizeof(fd);
    cmsg.header.level = SOL_SOCKET;
    cmsg.header.type  = SCM_RIGHTS;
    cmsg.fd           = -1;
    msghdr.msg_control    = &cmsg;
    msghdr.msg_controllen = sizeof(cmsg.header) + sizeof(fd);
    msghdr.msg_flags      = 0;
#endif  /* HAVE_STRUCT_MSGHDR_MSG_ACCRIGHTS */

    msghdr.msg_name    = NULL;
    msghdr.msg_namelen = 0;
    msghdr.msg_iov     = &vec;
    msghdr.msg_iovlen  = 1;
    vec.iov_base = (void *)handle;
    vec.iov_len  = sizeof(*handle);

    for (;;)
    {
        if ((ret = recvmsg( fd_socket, &msghdr, 0 )) > 0)
        {
#ifndef HAVE_STRUCT_MSGHDR_MSG_ACCRIGHTS
            fd = cmsg.fd;
#endif
            if (fd != -1) fcntl( fd, F_SETFD, 1 ); /* set close on exec flag */
            return fd;
        }
        if (!ret) break;
        if (errno == EINTR) continue;
        if (errno == EPIPE) break;
        server_protocol_perror("recvmsg");
    }
    /* the server closed the connection; time to die... */
    server_abort_thread(0);
}


inline static unsigned int handle_to_index( obj_handle_t handle )
{
    return ((unsigned long)handle >> 2) - 1;
}

struct fd_cache_entry
{
    int fd;
    enum server_fd_type type;
};

static struct fd_cache_entry *fd_cache;
static unsigned int fd_cache_size;

/***********************************************************************
 *           add_fd_to_cache
 *
 * Caller must hold fd_cache_section.
 */
static int add_fd_to_cache( obj_handle_t handle, int fd, enum server_fd_type type )
{
    unsigned int idx = handle_to_index( handle );

    if (idx >= fd_cache_size)
    {
        unsigned int i, size = max( 32, fd_cache_size * 2 );
        struct fd_cache_entry *new_cache;

        if (size <= idx) size = idx + 1;
        if (fd_cache)
            new_cache = RtlReAllocateHeap( GetProcessHeap(), 0, fd_cache, size*sizeof(fd_cache[0]) );
        else
            new_cache = RtlAllocateHeap( GetProcessHeap(), 0, size*sizeof(fd_cache[0]) );

        if (new_cache)
        {
            for (i = fd_cache_size; i < size; i++) new_cache[i].fd = -1;
            fd_cache = new_cache;
            fd_cache_size = size;
        }
    }
    if (idx < fd_cache_size)
    {
        assert( fd_cache[idx].fd == -1 );
        fd_cache[idx].fd   = fd;
        fd_cache[idx].type = type;
        TRACE("added %p (%d) type %d to cache\n", handle, fd, type );
        return 1;
    }
    return 0;
}


/***********************************************************************
 *           get_cached_fd
 *
 * Caller must hold fd_cache_section.
 */
static inline int get_cached_fd( obj_handle_t handle, enum server_fd_type *type )
{
    unsigned int idx = handle_to_index( handle );
    int fd = -1;

    if (idx < fd_cache_size)
    {
        fd = fd_cache[idx].fd;
        if (type) *type = fd_cache[idx].type;
    }
    return fd;
}


/***********************************************************************
 *           server_remove_fd_from_cache
 */
int server_remove_fd_from_cache( obj_handle_t handle )
{
    unsigned int idx = handle_to_index( handle );
    int fd = -1;

    RtlEnterCriticalSection( &fd_cache_section );
    if (idx < fd_cache_size)
    {
        fd = fd_cache[idx].fd;
        fd_cache[idx].fd = -1;
    }
    RtlLeaveCriticalSection( &fd_cache_section );

    if (fd != -1)
    {
        close( fd );
        TRACE("removed %p (%d) from cache\n", handle, fd );
    }
    return fd;
}


/***********************************************************************
 *           server_get_unix_fd
 *
 * The returned unix_fd should be closed iff needs_close is non-zero.
 */
int server_get_unix_fd( obj_handle_t handle, unsigned int access, int *unix_fd,
                        int *needs_close, enum server_fd_type *type, int *flags )
{
    obj_handle_t fd_handle;
    int ret = 0, removable = 0, fd;

    *unix_fd = -1;
    *needs_close = 0;

    RtlEnterCriticalSection( &fd_cache_section );

    fd = get_cached_fd( handle, type );
    if (fd != -1 && !flags) goto done;

    SERVER_START_REQ( get_handle_fd )
    {
        req->handle = handle;
        req->access = access;
        req->cached = (fd != -1);
        if (!(ret = wine_server_call( req )))
        {
            removable = reply->flags & FD_FLAG_REMOVABLE;
            if (type) *type = reply->type;
            if (flags) *flags = reply->flags;
            if (fd == -1)
            {
                if ((fd = receive_fd( &fd_handle )) != -1)
                {
                    assert( fd_handle == handle );
                    *needs_close = removable || !add_fd_to_cache( handle, fd, reply->type );
                }
                else ret = STATUS_TOO_MANY_OPENED_FILES;
            }
        }
    }
    SERVER_END_REQ;

done:
    RtlLeaveCriticalSection( &fd_cache_section );
    if (!ret) *unix_fd = fd;
    return ret;
}


/***********************************************************************
 *           wine_server_fd_to_handle   (NTDLL.@)
 *
 * Allocate a file handle for a Unix file descriptor.
 *
 * PARAMS
 *     fd      [I] Unix file descriptor.
 *     access  [I] Win32 access flags.
 *     attributes [I] Object attributes.
 *     handle  [O] Address where Wine file handle will be stored.
 *
 * RETURNS
 *     NTSTATUS code
 */
int wine_server_fd_to_handle( int fd, unsigned int access, unsigned int attributes, obj_handle_t *handle )
{
    int ret;

    *handle = 0;
    wine_server_send_fd( fd );

    SERVER_START_REQ( alloc_file_handle )
    {
        req->access     = access;
        req->attributes = attributes;
        req->fd         = fd;
        if (!(ret = wine_server_call( req ))) *handle = reply->handle;
    }
    SERVER_END_REQ;
    return ret;
}


/***********************************************************************
 *           wine_server_handle_to_fd   (NTDLL.@)
 *
 * Retrieve the file descriptor corresponding to a file handle.
 *
 * PARAMS
 *     handle  [I] Wine file handle.
 *     access  [I] Win32 file access rights requested.
 *     unix_fd [O] Address where Unix file descriptor will be stored.
 *     flags   [O] Address where the Unix flags associated with file will be stored. Optional.
 *
 * RETURNS
 *     NTSTATUS code
 */
int wine_server_handle_to_fd( obj_handle_t handle, unsigned int access, int *unix_fd, int *flags )
{
    int needs_close, ret = server_get_unix_fd( handle, access, unix_fd, &needs_close, NULL, flags );

    if (!ret && !needs_close)
    {
        if ((*unix_fd = dup(*unix_fd)) == -1) ret = FILE_GetNtStatus();
    }
    return ret;
}


/***********************************************************************
 *           wine_server_release_fd   (NTDLL.@)
 *
 * Release the Unix file descriptor returned by wine_server_handle_to_fd.
 *
 * PARAMS
 *     handle  [I] Wine file handle.
 *     unix_fd [I] Unix file descriptor to release.
 *
 * RETURNS
 *     nothing
 */
void wine_server_release_fd( obj_handle_t handle, int unix_fd )
{
    close( unix_fd );
}


/***********************************************************************
 *           start_server
 *
 * Start a new wine server.
 */
static void start_server(void)
{
    static int started;  /* we only try once */
    char *argv[3];
    static char wineserver[] = "server/wineserver";
    static char debug[] = "-d";

    if (!started)
    {
        int status;
        int pid = fork();
        if (pid == -1) fatal_perror( "fork" );
        if (!pid)
        {
            argv[0] = wineserver;
            argv[1] = TRACE_ON(server) ? debug : NULL;
            argv[2] = NULL;
            wine_exec_wine_binary( argv[0], argv, getenv("WINESERVER") );
            fatal_error( "could not exec wineserver\n" );
        }
        waitpid( pid, &status, 0 );
        status = WIFEXITED(status) ? WEXITSTATUS(status) : 1;
        if (status == 2) return;  /* server lock held by someone else, will retry later */
        if (status) exit(status);  /* server failed */
        started = 1;
    }
}


/***********************************************************************
 *           server_connect_error
 *
 * Try to display a meaningful explanation of why we couldn't connect
 * to the server.
 */
static void server_connect_error( const char *serverdir )
{
    int fd;
    struct flock fl;

    if ((fd = open( LOCKNAME, O_WRONLY )) == -1)
        fatal_error( "for some mysterious reason, the wine server never started.\n" );

    fl.l_type   = F_WRLCK;
    fl.l_whence = SEEK_SET;
    fl.l_start  = 0;
    fl.l_len    = 1;
    if (fcntl( fd, F_GETLK, &fl ) != -1)
    {
        if (fl.l_type == F_WRLCK)  /* the file is locked */
            fatal_error( "a wine server seems to be running, but I cannot connect to it.\n"
                         "   You probably need to kill that process (it might be pid %d).\n",
                         (int)fl.l_pid );
        fatal_error( "for some mysterious reason, the wine server failed to run.\n" );
    }
    fatal_error( "the file system of '%s' doesn't support locks,\n"
          "   and there is a 'socket' file in that directory that prevents wine from starting.\n"
          "   You should make sure no wine server is running, remove that file and try again.\n",
                 serverdir );
}


/***********************************************************************
 *           server_connect
 *
 * Attempt to connect to an existing server socket.
 * We need to be in the server directory already.
 */
static int server_connect( const char *serverdir )
{
    struct sockaddr_un addr;
    struct stat st;
    int s, slen, retry, fd_cwd;

    /* retrieve the current directory */
    fd_cwd = open( ".", O_RDONLY );
    if (fd_cwd != -1) fcntl( fd_cwd, F_SETFD, 1 ); /* set close on exec flag */

    /* chdir to the server directory */
    if (chdir( serverdir ) == -1)
    {
        if (errno != ENOENT) fatal_perror( "chdir to %s", serverdir );
        start_server();
        if (chdir( serverdir ) == -1) fatal_perror( "chdir to %s", serverdir );
    }

    /* make sure we are at the right place */
    if (stat( ".", &st ) == -1) fatal_perror( "stat %s", 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 );

    for (retry = 0; retry < 6; retry++)
    {
        /* if not the first try, wait a bit to leave the previous server time to exit */
        if (retry)
        {
            usleep( 100000 * retry * retry );
            start_server();
            if (lstat( SOCKETNAME, &st ) == -1) continue;  /* still no socket, wait a bit more */
        }
        else if (lstat( SOCKETNAME, &st ) == -1) /* check for an already existing socket */
        {
            if (errno != ENOENT) fatal_perror( "lstat %s/%s", serverdir, SOCKETNAME );
            start_server();
            if (lstat( SOCKETNAME, &st ) == -1) continue;  /* still no socket, wait a bit more */
        }

        /* make sure the socket is sane (ISFIFO needed for Solaris) */
        if (!S_ISSOCK(st.st_mode) && !S_ISFIFO(st.st_mode))
            fatal_error( "'%s/%s' is not a socket\n", serverdir, SOCKETNAME );
        if (st.st_uid != getuid())
            fatal_error( "'%s/%s' is not owned by you\n", serverdir, SOCKETNAME );

        /* try to connect to it */
        addr.sun_family = AF_UNIX;
        strcpy( addr.sun_path, SOCKETNAME );
        slen = sizeof(addr) - sizeof(addr.sun_path) + strlen(addr.sun_path) + 1;
#ifdef HAVE_STRUCT_SOCKADDR_UN_SUN_LEN
        addr.sun_len = slen;
#endif
        if ((s = socket( AF_UNIX, SOCK_STREAM, 0 )) == -1) fatal_perror( "socket" );
        if (connect( s, (struct sockaddr *)&addr, slen ) != -1)
        {
            /* switch back to the starting directory */
            if (fd_cwd != -1)
            {
                fchdir( fd_cwd );
                close( fd_cwd );
            }
            fcntl( s, F_SETFD, 1 ); /* set close on exec flag */
            return s;
        }
        close( s );
    }
    server_connect_error( serverdir );
}


/***********************************************************************
 *           rm_rf
 *
 * Remove a directory and all its contents; helper for create_config_dir.
 */
static void rm_rf( const char *path )
{
    int err = errno;  /* preserve errno */
    DIR *dir;
    char *buffer, *p;
    struct stat st;
    struct dirent *de;

    if (!(buffer = malloc( strlen(path) + 256 + 1 ))) goto done;
    strcpy( buffer, path );
    p = buffer + strlen(buffer);
    *p++ = '/';

    if ((dir = opendir( path )))
    {
        while ((de = readdir( dir )))
        {
            if (!strcmp( de->d_name, "." ) || !strcmp( de->d_name, ".." )) continue;
            strcpy( p, de->d_name );
            if (unlink( buffer ) != -1) continue;
            if (errno == EISDIR ||
                (errno == EPERM && !lstat( buffer, &st ) && S_ISDIR(st.st_mode)))
            {
                /* recurse in the sub-directory */
                rm_rf( buffer );
            }
        }
        closedir( dir );
    }
    free( buffer );
    rmdir( path );
done:
    errno = err;
}


/***********************************************************************
 *           create_config_dir
 *
 * Create the wine configuration dir (~/.wine).
 */
static void create_config_dir(void)
{
    const char *config_dir = wine_get_config_dir();
    char *tmp_dir;
    int fd;
    pid_t pid, wret;

    if (!(tmp_dir = malloc( strlen(config_dir) + sizeof("-XXXXXX") )))
        fatal_error( "out of memory\n" );
    strcpy( tmp_dir, config_dir );
    strcat( tmp_dir, "-XXXXXX" );
    if ((fd = mkstemps( tmp_dir, 0 )) == -1)
        fatal_perror( "can't get temp file name for %s", config_dir );
    close( fd );
    unlink( tmp_dir );
    if (mkdir( tmp_dir, 0777 ) == -1)
        fatal_perror( "cannot create temp dir %s", tmp_dir );

    MESSAGE( "wine: creating configuration directory '%s'...\n", config_dir );
    pid = fork();
    if (pid == -1)
    {
        rmdir( tmp_dir );
        fatal_perror( "fork" );
    }
    if (!pid)
    {
        char *argv[6];
        static char argv0[] = "tools/wineprefixcreate",
                    argv1[] = "--quiet",
                    argv2[] = "--wait",
                    argv3[] = "--prefix";

        argv[0] = argv0;
        argv[1] = argv1;
        argv[2] = argv2;
        argv[3] = argv3;
        argv[4] = tmp_dir;
        argv[5] = NULL;
        wine_exec_wine_binary( argv[0], argv, NULL );
        rmdir( tmp_dir );
        fatal_perror( "could not exec wineprefixcreate" );
    }
    else
    {
        int status;

        while ((wret = waitpid( pid, &status, 0 )) != pid)
        {
            if (wret == -1 && errno != EINTR) fatal_perror( "wait4" );
        }
        if (!WIFEXITED(status) || WEXITSTATUS(status))
        {
            rm_rf( tmp_dir );
            fatal_error( "wineprefixcreate failed while creating '%s'.\n", config_dir );
        }
    }
    if (rename( tmp_dir, config_dir ) == -1)
    {
        rm_rf( tmp_dir );
        if (errno != EEXIST && errno != ENOTEMPTY)
            fatal_perror( "rename '%s' to '%s'", tmp_dir, config_dir );
        /* else it was probably created by a concurrent wine process */
    }
    free( tmp_dir );
    MESSAGE( "wine: '%s' created successfully.\n", config_dir );
}


/***********************************************************************
 *           server_init_process
 *
 * Start the server and create the initial socket pair.
 */
void server_init_process(void)
{
    obj_handle_t dummy_handle;
    const char *env_socket = getenv( "WINESERVERSOCKET" );

    if (env_socket)
    {
        fd_socket = atoi( env_socket );
        if (fcntl( fd_socket, F_SETFD, 1 ) == -1)
            fatal_perror( "Bad server socket %d", fd_socket );
    }
    else
    {
        const char *server_dir = wine_get_server_dir();

        if (!server_dir)  /* this means the config dir doesn't exist */
        {
            create_config_dir();
            server_dir = wine_get_server_dir();
        }

        /* connect to the server */
        fd_socket = server_connect( server_dir );
    }

    /* setup the signal mask */
    sigemptyset( &block_set );
    sigaddset( &block_set, SIGALRM );
    sigaddset( &block_set, SIGIO );
    sigaddset( &block_set, SIGINT );
    sigaddset( &block_set, SIGHUP );
    sigaddset( &block_set, SIGUSR1 );
    sigaddset( &block_set, SIGUSR2 );
    sigaddset( &block_set, SIGCHLD );

    /* receive the first thread request fd on the main socket */
    ntdll_get_thread_data()->request_fd = receive_fd( &dummy_handle );
}


/***********************************************************************
 *           server_init_thread
 *
 * Send an init thread request. Return 0 if OK.
 */
size_t server_init_thread( int unix_pid, int unix_tid, void *entry_point )
{
    int version, ret;
    int reply_pipe[2];
    struct sigaction sig_act;
    size_t info_size;

    sig_act.sa_handler = SIG_IGN;
    sig_act.sa_flags   = 0;
    sigemptyset( &sig_act.sa_mask );

    /* ignore SIGPIPE so that we get an EPIPE error instead  */
    sigaction( SIGPIPE, &sig_act, NULL );
    /* automatic child reaping to avoid zombies */
#ifdef SA_NOCLDWAIT
    sig_act.sa_flags |= SA_NOCLDWAIT;
#endif
    sigaction( SIGCHLD, &sig_act, NULL );

    /* create the server->client communication pipes */
    if (pipe( reply_pipe ) == -1) server_protocol_perror( "pipe" );
    if (pipe( ntdll_get_thread_data()->wait_fd ) == -1) server_protocol_perror( "pipe" );
    wine_server_send_fd( reply_pipe[1] );
    wine_server_send_fd( ntdll_get_thread_data()->wait_fd[1] );
    ntdll_get_thread_data()->reply_fd = reply_pipe[0];
    close( reply_pipe[1] );

    /* set close on exec flag */
    fcntl( ntdll_get_thread_data()->reply_fd, F_SETFD, 1 );
    fcntl( ntdll_get_thread_data()->wait_fd[0], F_SETFD, 1 );
    fcntl( ntdll_get_thread_data()->wait_fd[1], F_SETFD, 1 );

    SERVER_START_REQ( init_thread )
    {
        req->unix_pid    = unix_pid;
        req->unix_tid    = unix_tid;
        req->teb         = NtCurrentTeb();
        req->peb         = NtCurrentTeb()->Peb;
        req->entry       = entry_point;
        req->ldt_copy    = &wine_ldt_copy;
        req->reply_fd    = reply_pipe[1];
        req->wait_fd     = ntdll_get_thread_data()->wait_fd[1];
        req->debug_level = (TRACE_ON(server) != 0);
        ret = wine_server_call( req );
        NtCurrentTeb()->ClientId.UniqueProcess = (HANDLE)reply->pid;
        NtCurrentTeb()->ClientId.UniqueThread  = (HANDLE)reply->tid;
        info_size         = reply->info_size;
        version           = reply->version;
        server_start_time = reply->server_start;
    }
    SERVER_END_REQ;

    if (ret) server_protocol_error( "init_thread failed with status %x\n", ret );
    if (version != SERVER_PROTOCOL_VERSION)
        server_protocol_error( "version mismatch %d/%d.\n"
                               "Your %s binary was not upgraded correctly,\n"
                               "or you have an older one somewhere in your PATH.\n"
                               "Or maybe the wrong wineserver is still running?\n",
                               version, SERVER_PROTOCOL_VERSION,
                               (version > SERVER_PROTOCOL_VERSION) ? "wine" : "wineserver" );
    return info_size;
}