/*
 *    Support routines for file descriptors (FD)
 *
 *	James Peterson, 1987
 *
 * Copyright (C) 1987 MCC
 *
 * Permission to use, copy, modify, distribute, and sell this software and its
 * documentation for any purpose is hereby granted without fee, provided that
 * the above copyright notice appear in all copies and that both that
 * copyright notice and this permission notice appear in supporting
 * documentation, and that the name of MCC not be used in
 * advertising or publicity pertaining to distribution of the software without
 * specific, written prior permission.  MCC makes no
 * representations about the suitability of this software for any purpose.  It
 * is provided "as is" without express or implied warranty.
 *
 * MCC DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
 * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
 * EVENT SHALL MCC BE LIABLE FOR ANY SPECIAL, INDIRECT OR
 * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
 * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
 * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
 * PERFORMANCE OF THIS SOFTWARE.
 *
 */
/*
 * Copyright (c) 2002, Oracle and/or its affiliates. All rights reserved.
 *
 * 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 (including the next
 * paragraph) 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 <X11/Xpoll.h>          /* for XFD_* macros - must come before
                                   scope.h include to avoid INT32 clash */

#include "scope.h"

#include <unistd.h>
#include <sys/uio.h>            /* for struct iovec, used by socket.h */
#include <sys/socket.h>         /* for AF_INET, SOCK_STREAM, ... */
#include <sys/ioctl.h>          /* for FIONCLEX, FIONBIO, ... */
#if !defined(FIOCLEX) && defined(HAVE_SYS_FILIO_H)
#include <sys/filio.h>
#endif
#include <fcntl.h>
#include <netinet/in.h>         /* struct sockaddr_in */
#include <sys/un.h>             /* struct sockaddr_un */
#include <netinet/tcp.h>
#include <netdb.h>              /* struct servent * and struct hostent * */
#include <errno.h>              /* for EINTR, EADDRINUSE, ... */

#ifndef USE_XTRANS
#include <arpa/inet.h>          /* for inet_addr */
#endif

/*
  All of this code is to support the handling of file descriptors (FD).
  The idea is to keep a table of the FDs that are in use and why.
  For each FD that is open for input, we keep the name of a procedure
  to call if input arrives for that FD.  When an FD is created
  (by an open, pipe, socket, ...) declare that by calling UsingFD.
  When it is no longer in use (close ...), call NotUsingFD.
*/

/* ************************************************************ */
/*								*/
/*								*/
/* ************************************************************ */

void
InitializeFD(void)
{
    int i;

    enterprocedure("InitializeFD");
    /* get the number of file descriptors the system will let us use */
#ifdef _SC_OPEN_MAX
    MaxFD = sysconf(_SC_OPEN_MAX);
#elif defined(HAVE_GETDTABLESIZE)
    MaxFD = getdtablesize();
#else
    MaxFD = _NFILE - 1;
#endif
    if (MaxFD > FD_SETSIZE) {
        MaxFD = FD_SETSIZE;
    }

    /* allocate space for a File Descriptor (FD) Table */
    FDD = calloc(MaxFD, sizeof(struct FDDescriptor));
    if (FDD == NULL) {
        panic("Can't allocate memory for file descriptor table");
    }
    FDinfo = calloc(MaxFD, sizeof(struct fdinfo));
    if (FDinfo == NULL) {
        panic("Can't allocate memory for file descriptor info table");
    }

    /* be sure all fd's are closed and marked not busy */
    for (i = 0; i < MaxFD; i++) {
        /* 0, 1, 2 are special (stdin, stdout, stderr) */
        if (i > 2)
            close(i);
        /* FDD[i].Busy = false; - not needed since false==0 */
    }

    /* save one FD for single file input or output like debugging */
    /* also the getservbyname call is currently using an FD */
    MaxFD -= 4;

    nFDsInUse = 0; /* stdin, stdout, stderr */
    FD_ZERO(&ReadDescriptors);
    HighestFD = 0;

    UsingFD(fileno(stdin), NULL, NULL, NULL);
    UsingFD(fileno(stdout), NULL, NULL, NULL);
    UsingFD(fileno(stderr), NULL, NULL, NULL);
}

/* ************************************************************ */

const char *
GetPeerInfo(FD fd)
{
    return FDD[fd].peer_info;
}

/* ************************************************************ */

void
UsingFD(FD fd,
        void (*Handler) (int),
        void (*FlushHandler) (int),
        XtransConnInfo trans_conn)
{
    if (FDD[fd].Busy)
        NotUsingFD(fd);
    nFDsInUse += 1;

    FDD[fd].Busy = true;
    FDD[fd].InputHandler = Handler;
    FDD[fd].FlushHandler = FlushHandler;
#ifdef USE_XTRANS
    FDD[fd].trans_conn = trans_conn;
#endif
    FDD[fd].peer_info = ReadPeerInfo(fd);
    if (Handler == NULL)
        FD_CLR(fd, &ReadDescriptors); /* clear fd bit */
    else
        FD_SET(fd, &ReadDescriptors); /* set fd bit */

    if (fd > HighestFD)
        HighestFD = fd;

    if (nFDsInUse >= MaxFD)
        panic("no more FDs");

    debug(128,
          (stderr, "Using FD %d, %d of %d in use\n", fd, nFDsInUse, MaxFD));
}

/* ************************************************************ */

void
NotUsingFD(FD fd)
{
    debug(128, (stderr, "Not Using FD %d\n", fd));

    if (FDD[fd].Busy)
        nFDsInUse -= 1;

    FDD[fd].Busy = false;
    FD_CLR(fd, &ReadDescriptors); /* clear fd bit */

    free(FDD[fd].peer_info);
    FDD[fd].peer_info = NULL;

    while (!FDD[HighestFD].Busy && HighestFD > 0)
        HighestFD -= 1;

    debug(128, (stderr, "Highest FD %d, in use %d\n", HighestFD, nFDsInUse));
}

/* ************************************************************ */

#ifdef USE_XTRANS
XtransConnInfo
GetXTransConnInfo(FD fd)
{
    return FDD[fd].trans_conn;
}
#endif

/* ************************************************************ */

void
CloseFD(FD fd)
{
#ifdef USE_XTRANS
    XtransConnInfo conn = GetXTransConnInfo(fd);

    if (conn)
        _X11TransClose(conn);
    else
#endif
        close(fd);

    NotUsingFD(fd);
}

/* ************************************************************ */

static void
EOFonFD(FD fd)
{
    enterprocedure("EOFonFD");
    debug(128, (stderr, "EOF on %d\n", fd));
    CloseFD(fd);
}

FD
AcceptConnection(FD ConnectionSocket)
{
    FD ClientFD;
    struct sockaddr_in from;
    socklen_t len = sizeof(from);
    int tmp = 1;

    enterprocedure("ConnectToClient");

    ClientFD = accept(ConnectionSocket, (struct sockaddr *) &from, &len);
    debug(4, (stderr, "Connect To Client: FD %d\n", ClientFD));
    if (ClientFD < 0 && errno == EWOULDBLOCK) {
        debug(4, (stderr, "Almost blocked accepting FD %d\n", ClientFD));
        panic("Can't connect to Client");
    }
    if (ClientFD < 0) {
        debug(4, (stderr, "NewConnection: error %d\n", errno));
        panic("Can't connect to Client");
    }

#ifdef FD_CLOEXEC
    (void) fcntl(ClientFD, F_SETFD, FD_CLOEXEC);
#else
    (void) ioctl(ClientFD, FIOCLEX, 0);
#endif
    /* ultrix reads hang on Unix sockets, hpux reads fail */
#if defined(O_NONBLOCK) && (!defined(ultrix) && !defined(hpux))
    (void) fcntl(ClientFD, F_SETFL, O_NONBLOCK);
#else
#ifdef FIOSNBIO
    ioctl(ClientFD, FIOSNBIO, &ON);
#else
    (void) fcntl(ClientFD, F_SETFL, FNDELAY);
#endif
#endif
    (void) setsockopt(ClientFD, IPPROTO_TCP, TCP_NODELAY, (char *) &tmp,
                      sizeof(int));
    return (ClientFD);
}

FD
MakeConnection(const char *server, short port, int report,
               XtransConnInfo *trans_conn  /* transport connection object */)
{
    FD ServerFD;

#ifdef USE_XTRANS
    char address[256];
    int connect_stat;
    const char *protocols[] = { "local", "unix", "tcp", "inet6", "inet", NULL };
    const char **s;

    enterprocedure("ConnectToServer");
    s = protocols;
    while (*s) {
        *trans_conn = NULL;
        snprintf(address, sizeof(address), "%s/%s:%ld",
                 *s++, server, port - ServerBasePort);
        debug(4, (stderr, "Trying %s ", address));
        *trans_conn = _X11TransOpenCOTSClient(address);
        if (*trans_conn == NULL) {
            debug(1, (stderr, "OpenCOTSClient %s failed\n", address));
            continue;
        }
        debug(4, (stderr, "Opened "));
        if ((connect_stat = _X11TransConnect(*trans_conn, address)) < 0) {
            if ((connect_stat != TRANS_TRY_CONNECT_AGAIN) ||
                (_X11TransConnect(*trans_conn, address) < 0)) {
                _X11TransClose(*trans_conn);
                *trans_conn = NULL;
                debug(1, (stderr, "TransConnect %s failed\n", address));
                continue;
            }
        }
        debug(4, (stderr, "Connected\n"));
        break;
    }
    if (*trans_conn == NULL) {
        panic("Can't open connection to Server");
    }

    ServerFD = _X11TransGetConnectionNumber(*trans_conn);
#else                           /* !USE_XTRANS */
    char HostName[512];
    struct sockaddr_in sin;
    struct sockaddr_un saun;
    struct sockaddr *saddr;
    int salen;
    struct hostent *hp;
    int tmp = 1;
#ifndef	SO_DONTLINGER
    struct linger linger;
#endif                          /* SO_DONTLINGER */

    enterprocedure("ConnectToServer");

    /* establish a socket to the name server for this host */
    /* determine the host machine for this process */
    if (*server == '\0') {
        saun.sun_family = AF_UNIX;
        snprintf(saun.sun_path, sizeof(saun.sun_path),
                 "/tmp/.X11-unix/X%d", port - 6000);
        salen = sizeof(saun.sun_family) + strlen(saun.sun_path) + 1;
        saddr = (struct sockaddr *) &saun;
    }
    else {
        debug(4, (stderr, "try to connect on %s\n", server));

        bzero((char *) &sin, sizeof(sin));
        sin.sin_addr.s_addr = inet_addr(server);
        if ((long) sin.sin_addr.s_addr == -1) {
            hp = gethostbyname(server);
            if (hp == 0) {
                perror("gethostbyname failed");
                debug(1, (stderr, "gethostbyname failed for %s\n", server));
                panic("Can't open connection to Server");
            }
            memcpy(&sin.sin_addr, hp->h_addr, hp->h_length);
        }

        sin.sin_family = AF_INET;

        if (port == ScopePort && strcmp(server, ScopeHost) == 0) {
            char error_message[100];

            snprintf(error_message, sizeof(error_message),
                     "Trying to attach to myself: %s,%d\n",
                     server, sin.sin_port);
            panic(error_message);
        }

        sin.sin_port = htons(port);
        salen = sizeof(sin);
        saddr = (struct sockaddr *) &sin;
    }

    ServerFD = socket(saddr->sa_family, SOCK_STREAM, 0);
    if (ServerFD < 0) {
        perror("socket() to Server failed");
        debug(1, (stderr, "socket failed\n"));
        panic("Can't open connection to Server");
    }
    (void) setsockopt(ServerFD, SOL_SOCKET, SO_REUSEADDR, (char *) NULL, 0);
#ifdef SO_USELOOPBACK
    (void) setsockopt(ServerFD, SOL_SOCKET, SO_USELOOPBACK, (char *) NULL, 0);
#endif
    (void) setsockopt(ServerFD, IPPROTO_TCP, TCP_NODELAY, (char *) &tmp,
                      sizeof(int));
#ifdef	SO_DONTLINGER
    (void) setsockopt(ServerFD, SOL_SOCKET, SO_DONTLINGER, (char *) NULL, 0);
#else                           /* SO_DONTLINGER */
    linger.l_onoff = 0;
    linger.l_linger = 0;
    (void) setsockopt(ServerFD, SOL_SOCKET, SO_LINGER, (char *) &linger,
                      sizeof linger);
#endif                          /* SO_DONTLINGER */

    /* ******************************************************** */
    /* try to connect to Server */

    if (connect(ServerFD, saddr, salen) < 0) {
        debug(4, (stderr, "connect returns errno of %d\n", errno));
        if (errno != 0)
            if (report)
                perror("connect");
        switch (errno) {
        case ECONNREFUSED:
            /* experience says this is because there is no Server
               to connect to */
            (void) close(ServerFD);
            debug(1, (stderr, "No Server\n"));
            if (report)
                warn("Can't open connection to Server");
            return (-1);

        default:
            (void) close(ServerFD);
            panic("Can't open connection to Server");
        }
    }
#endif                          /* USE_XTRANS */

    debug(4, (stderr, "Connect To Server: FD %d\n", ServerFD));
    return (ServerFD);
}

/* ************************************************************ */
/*								*/
/*     Main Loop -- wait for input from any source and Process  */
/*								*/
/* ************************************************************ */

int
MainLoop(void)
{
    enterprocedure("MainLoop");

    while (true) {
        fd_set rfds, wfds, xfds;
        short nfds;
        short fd;

        /* wait for something */

        /* rfds = ReadDescriptors & ~BlockedReadDescriptors; */
        rfds = ReadDescriptors;
        XFD_UNSET(&rfds, &BlockedReadDescriptors);

        xfds = rfds;

        /* wfds = ReadDescriptors & WriteDescriptors; */
        XFD_ANDSET(&wfds, &ReadDescriptors, &WriteDescriptors);

        debug(128,
              (stderr,
               "select %d, rfds = %#lx, wfds = %#lx, RD=%#lx, BRD=%#lx, WD=%#lx\n",
               HighestFD + 1, __XFDS_BITS(&rfds, 0), __XFDS_BITS(&wfds, 0),
               __XFDS_BITS(&ReadDescriptors, 0),
               __XFDS_BITS(&BlockedReadDescriptors, 0),
               __XFDS_BITS(&WriteDescriptors, 0)));

        if (Interrupt || (!XFD_ANYSET(&rfds) && !XFD_ANYSET(&wfds))) {
            ReadCommands();
            Interrupt = 0;
            continue;
        }
        nfds =
            select(HighestFD + 1, &rfds, &wfds, &xfds, (struct timeval *) NULL);
        debug(128,
              (stderr,
               "select nfds = %d, rfds = %#lx, wfds = %#lx, xfds = %#lx\n",
               nfds, __XFDS_BITS(&rfds, 0), __XFDS_BITS(&wfds, 0),
               __XFDS_BITS(&xfds, 0)));

        if (nfds < 0) {
            if (errno == EINTR)
                continue; /* to end of while loop */
            debug(1, (stderr, "Bad select - errno = %d\n", errno));
            if (errno == EBADF) {
                /* one of the bits in rfds is invalid, close down
                   files until it goes away */
                EOFonFD(HighestFD);
                continue;
            }

            if (Interrupt) {
                ReadCommands();
                Interrupt = 0;
            }
            else {
                panic("Select returns error");
            }
            continue; /* to end of while loop */
        }

        if (nfds == 0) {
            TimerExpired();
            continue;
        }

        /* check each fd to see if it has input */
        for (fd = 0; fd <= HighestFD; fd++) {
            /*
               check all returned fd's; this prevents
               starvation of later clients by earlier clients
             */

            if (FD_ISSET(fd, &rfds)) {
                if (FDD[fd].InputHandler == NULL) {
                    debug(1, (stderr, "FD %d has NULL handler\n", fd));
                    panic("FD selected with no handler");
                }
                else
                    (FDD[fd].InputHandler) (fd);
            }
            if (FD_ISSET(fd, &wfds)) {
                if (FDD[fd].FlushHandler == NULL) {
                    panic("FD selected with no flush handler");
                }
                else
                    (FDD[fd].FlushHandler) (fd);
            }
        }
    }
    return 0;
}
