/* Copyright (C) 2001-2004 Bart Massey and Jamey Sharp.

 *

 * 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 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.

 * 

 * Except as contained in this notice, the names of the authors or their

 * institutions shall not be used in advertising or otherwise to promote the

 * sale, use or other dealings in this Software without prior written

 * authorization from the authors.

 */

/* Connection management: the core of XCB. */

#ifdef HAVE_CONFIG_H

#include "config.h"

#endif

#include <assert.h>

#include <string.h>

#include <stdio.h>

#include <unistd.h>

#include <stdlib.h>

#include <fcntl.h>

#include <errno.h>

#include <limits.h>

#include "xcb.h"

#include "xcbint.h"

#if USE_POLL

#include <poll.h>

#elif !defined _WIN32

#include <sys/select.h>

#endif

#ifdef _WIN32

#include "xcb_windefs.h"

#else

#include <sys/socket.h>

#include <netinet/in.h>

#endif /* _WIN32 */

/* SHUT_RDWR is fairly recent and is not available on all platforms */

#if !defined(SHUT_RDWR)

#define SHUT_RDWR 2

#endif

typedef struct {

    uint8_t  status;

    uint8_t  pad0[5];

    uint16_t length;

} xcb_setup_generic_t;

static const xcb_setup_t xcb_error_setup = {

    0,     /* status: failed (but we wouldn't have a xcb_setup_t in this case) */

    0,     /* pad0 */

    0, 0,  /* protocol version, should be 11.0, but isn't */

    0,     /* length, invalid value */

    0,     /* release_number */

    0, 0,  /* resource_id_{base,mask} */

    0,     /* motion_buffer_size */

    0,     /* vendor_len */

    0,     /* maximum_request_length */

    0,     /* roots_len */

    0,     /* pixmap_formats_len */

    0,     /* image_byte_order */

    0,     /* bitmap_format_bit_order */

    0,     /* bitmap_format_scanline_unit */

    0,     /* bitmap_format_scanline_pad */

    0, 0,  /* {min,max}_keycode */

    { 0, 0, 0, 0 } /* pad1 */

};

/* Keep this list in sync with is_static_error_conn()! */

static const int xcb_con_error = XCB_CONN_ERROR;

static const int xcb_con_closed_mem_er = XCB_CONN_CLOSED_MEM_INSUFFICIENT;

static const int xcb_con_closed_parse_er = XCB_CONN_CLOSED_PARSE_ERR;

static const int xcb_con_closed_screen_er = XCB_CONN_CLOSED_INVALID_SCREEN;

static int is_static_error_conn(xcb_connection_t *c)

{

    return c == (xcb_connection_t *) &xcb_con_error ||

           c == (xcb_connection_t *) &xcb_con_closed_mem_er ||

           c == (xcb_connection_t *) &xcb_con_closed_parse_er ||

           c == (xcb_connection_t *) &xcb_con_closed_screen_er;

}

static int set_fd_flags(const int fd)

{

/* Win32 doesn't have file descriptors and the fcntl function. This block sets the socket in non-blocking mode */

#ifdef _WIN32

   u_long iMode = 1; /* non-zero puts it in non-blocking mode, 0 in blocking mode */

   int ret = 0;

   ret = ioctlsocket(fd, FIONBIO, &iMode);

   if(ret != 0)

       return 0;

   return 1;

#else

    int flags = fcntl(fd, F_GETFL, 0);

    if(flags == -1)

        return 0;

    flags |= O_NONBLOCK;

    if(fcntl(fd, F_SETFL, flags) == -1)

        return 0;

    if(fcntl(fd, F_SETFD, FD_CLOEXEC) == -1)

        return 0;

    return 1;

#endif /* _WIN32 */

}

static int write_setup(xcb_connection_t *c, xcb_auth_info_t *auth_info)

{

    static const char pad[3];

    xcb_setup_request_t out;

    struct iovec parts[6];

    int count = 0;

    static const uint32_t endian = 0x01020304;

    int ret;

    memset(&out, 0, sizeof(out));

    /* B = 0x42 = MSB first, l = 0x6c = LSB first */

    if(htonl(endian) == endian)

        out.byte_order = 0x42;

    else

        out.byte_order = 0x6c;

    out.protocol_major_version = X_PROTOCOL;

    out.protocol_minor_version = X_PROTOCOL_REVISION;

    out.authorization_protocol_name_len = 0;

    out.authorization_protocol_data_len = 0;

    parts[count].iov_len = sizeof(xcb_setup_request_t);

    parts[count++].iov_base = &out;

    parts[count].iov_len = XCB_PAD(sizeof(xcb_setup_request_t));

    parts[count++].iov_base = (char *) pad;

    if(auth_info)

    {

        parts[count].iov_len = out.authorization_protocol_name_len = auth_info->namelen;

        parts[count++].iov_base = auth_info->name;

        parts[count].iov_len = XCB_PAD(out.authorization_protocol_name_len);

        parts[count++].iov_base = (char *) pad;

        parts[count].iov_len = out.authorization_protocol_data_len = auth_info->datalen;

        parts[count++].iov_base = auth_info->data;

        parts[count].iov_len = XCB_PAD(out.authorization_protocol_data_len);

        parts[count++].iov_base = (char *) pad;

    }

    assert(count <= (int) (sizeof(parts) / sizeof(*parts)));

    pthread_mutex_lock(&c->iolock);

    ret = _xcb_out_send(c, parts, count);

    pthread_mutex_unlock(&c->iolock);

    return ret;

}

static int read_setup(xcb_connection_t *c)

{

    /* Read the server response */

    c->setup = malloc(sizeof(xcb_setup_generic_t));

    if(!c->setup)

        return 0;

    if(_xcb_in_read_block(c, c->setup, sizeof(xcb_setup_generic_t)) != sizeof(xcb_setup_generic_t))

        return 0;

    {

        void *tmp = realloc(c->setup, c->setup->length * 4 + sizeof(xcb_setup_generic_t));

        if(!tmp)

            return 0;

        c->setup = tmp;

    }

    if(_xcb_in_read_block(c, (char *) c->setup + sizeof(xcb_setup_generic_t), c->setup->length * 4) <= 0)

        return 0;

    /* 0 = failed, 2 = authenticate, 1 = success */

    switch(c->setup->status)

    {

    case 0: /* failed */

        {

            xcb_setup_failed_t *setup = (xcb_setup_failed_t *) c->setup;

            write(STDERR_FILENO, xcb_setup_failed_reason(setup), xcb_setup_failed_reason_length(setup));

            return 0;

        }

    case 2: /* authenticate */

        {

            xcb_setup_authenticate_t *setup = (xcb_setup_authenticate_t *) c->setup;

            write(STDERR_FILENO, xcb_setup_authenticate_reason(setup), xcb_setup_authenticate_reason_length(setup));

            return 0;

        }

    }

    return 1;

}

/* precondition: there must be something for us to write. */

static int write_vec(xcb_connection_t *c, struct iovec **vector, int *count)

{

    int n;

    assert(!c->out.queue_len);

#ifdef _WIN32

    int i = 0;

    int ret = 0,err = 0;

    struct iovec *vec;

    n = 0;

    /* Could use the WSASend win32 function for scatter/gather i/o but setting up the WSABUF struct from

       an iovec would require more work and I'm not sure of the benefit....works for now */

    vec = *vector;

    while(i < *count)

    {

         ret = send(c->fd,vec->iov_base,vec->iov_len,0);

         if(ret == SOCKET_ERROR)

         {

             err  = WSAGetLastError();

             if(err == WSAEWOULDBLOCK)

             {

                 return 1;

             }

         }

         n += ret;

         *vec++;

         i++;

    }

#else

    n = *count;

    if (n > IOV_MAX)

        n = IOV_MAX;

#if HAVE_SENDMSG

    if (c->out.out_fd.nfd) {

        union {

            struct cmsghdr cmsghdr;

            char buf[CMSG_SPACE(XCB_MAX_PASS_FD * sizeof(int))];

        } cmsgbuf;

        struct msghdr msg = {

            .msg_name = NULL,

            .msg_namelen = 0,

            .msg_iov = *vector,

            .msg_iovlen = n,

            .msg_control = cmsgbuf.buf,

            .msg_controllen = CMSG_LEN(c->out.out_fd.nfd * sizeof (int)),

        };

        int i;

        struct cmsghdr *hdr = CMSG_FIRSTHDR(&msg;;

        hdr->cmsg_len = msg.msg_controllen;

        hdr->cmsg_level = SOL_SOCKET;

        hdr->cmsg_type = SCM_RIGHTS;

        memcpy(CMSG_DATA(hdr), c->out.out_fd.fd, c->out.out_fd.nfd * sizeof (int));

        n = sendmsg(c->fd, &msg, 0);

        if(n < 0 && errno == EAGAIN)

            return 1;

        for (i = 0; i < c->out.out_fd.nfd; i++)

            close(c->out.out_fd.fd[i]);

        c->out.out_fd.nfd = 0;

    } else

#endif

    {

        n = writev(c->fd, *vector, n);

        if(n < 0 && errno == EAGAIN)

            return 1;

    }

#endif /* _WIN32 */

    if(n <= 0)

    {

        _xcb_conn_shutdown(c, XCB_CONN_ERROR);

        return 0;

    }

    for(; *count; --*count, ++*vector)

    {

        int cur = (*vector)->iov_len;

        if(cur > n)

            cur = n;

        (*vector)->iov_len -= cur;

        (*vector)->iov_base = (char *) (*vector)->iov_base + cur;

        n -= cur;

        if((*vector)->iov_len)

            break;

    }

    if(!*count)

        *vector = 0;

    assert(n == 0);

    return 1;

}

/* Public interface */

const xcb_setup_t *xcb_get_setup(xcb_connection_t *c)

{

    if(is_static_error_conn(c))

        return &xcb_error_setup;

    /* doesn't need locking because it's never written to. */

    return c->setup;

}

int xcb_get_file_descriptor(xcb_connection_t *c)

{

    if(is_static_error_conn(c))

        return -1;

    /* doesn't need locking because it's never written to. */

    return c->fd;

}

int xcb_connection_has_error(xcb_connection_t *c)

{

    /* doesn't need locking because it's read and written atomically. */

    return c->has_error;

}

xcb_connection_t *xcb_connect_to_fd(int fd, xcb_auth_info_t *auth_info)

{

    xcb_connection_t* c;

#ifndef _WIN32

#ifndef USE_POLL

    if(fd >= FD_SETSIZE) /* would overflow in FD_SET */

    {

        close(fd);

        return _xcb_conn_ret_error(XCB_CONN_ERROR);

    }

#endif

#endif /* !_WIN32*/

    c = calloc(1, sizeof(xcb_connection_t));

    if(!c) {

        close(fd);

        return _xcb_conn_ret_error(XCB_CONN_CLOSED_MEM_INSUFFICIENT) ;

    }

    c->fd = fd;

    if(!(

        set_fd_flags(fd) &&

        pthread_mutex_init(&c->iolock, 0) == 0 &&

        _xcb_in_init(&c->in) &&

        _xcb_out_init(&c->out) &&

        write_setup(c, auth_info) &&

        read_setup(c) &&

        _xcb_ext_init(c) &&

        _xcb_xid_init(c)

        ))

    {

        xcb_disconnect(c);

        return _xcb_conn_ret_error(XCB_CONN_ERROR);

    }

    return c;

}

void xcb_disconnect(xcb_connection_t *c)

{

    if(c == NULL || is_static_error_conn(c))

        return;

    free(c->setup);

    /* disallow further sends and receives */

    shutdown(c->fd, SHUT_RDWR);

    close(c->fd);

    pthread_mutex_destroy(&c->iolock);

    _xcb_in_destroy(&c->in);

    _xcb_out_destroy(&c->out);

    _xcb_ext_destroy(c);

    _xcb_xid_destroy(c);

    free(c);

#ifdef _WIN32

    WSACleanup();

#endif

}

/* Private interface */

void _xcb_conn_shutdown(xcb_connection_t *c, int err)

{

    c->has_error = err;

}

/* Return connection error state.

 * To make thread-safe, I need a seperate static

 * variable for every possible error.

 * has_error is the first field in xcb_connection_t, so just

 * return a casted int here; checking has_error (and only

 * has_error) will be safe.

 */

xcb_connection_t *_xcb_conn_ret_error(int err)

{

    switch(err)

    {

        case XCB_CONN_CLOSED_MEM_INSUFFICIENT:

        {

            return (xcb_connection_t *) &xcb_con_closed_mem_er;

        }

        case XCB_CONN_CLOSED_PARSE_ERR:

        {

            return (xcb_connection_t *) &xcb_con_closed_parse_er;

        }

        case XCB_CONN_CLOSED_INVALID_SCREEN:

        {

            return (xcb_connection_t *) &xcb_con_closed_screen_er;

        }

        case XCB_CONN_ERROR:

        default:

        {

            return (xcb_connection_t *) &xcb_con_error;

        }

    }

}

int _xcb_conn_wait(xcb_connection_t *c, pthread_cond_t *cond, struct iovec **vector, int *count)

{

    int ret;

#if USE_POLL

    struct pollfd fd;

#else

    fd_set rfds, wfds;

#endif

    /* If the thing I should be doing is already being done, wait for it. */

    if(count ? c->out.writing : c->in.reading)

    {

        pthread_cond_wait(cond, &c->iolock);

        return 1;

    }

#if USE_POLL

    memset(&fd, 0, sizeof(fd));

    fd.fd = c->fd;

    fd.events = POLLIN;

#else

    FD_ZERO(&rfds);

    FD_SET(c->fd, &rfds);

#endif

    ++c->in.reading;

#if USE_POLL

    if(count)

    {

        fd.events |= POLLOUT;

        ++c->out.writing;

    }

#else

    FD_ZERO(&wfds);

    if(count)

    {

        FD_SET(c->fd, &wfds);

        ++c->out.writing;

    }

#endif

    pthread_mutex_unlock(&c->iolock);

    do {

#if USE_POLL

        ret = poll(&fd, 1, -1);

        /* If poll() returns an event we didn't expect, such as POLLNVAL, treat

         * it as if it failed. */

        if(ret >= 0 && (fd.revents & ~fd.events))

        {

            ret = -1;

            break;

        }

#else

        ret = select(c->fd + 1, &rfds, &wfds, 0, 0);

#endif

    } while (ret == -1 && errno == EINTR);

    if(ret < 0)

    {

        _xcb_conn_shutdown(c, XCB_CONN_ERROR);

        ret = 0;

    }

    pthread_mutex_lock(&c->iolock);

    if(ret)

    {

        /* The code allows two threads to call select()/poll() at the same time.

         * First thread just wants to read, a second thread wants to write, too.

         * We have to make sure that we don't steal the reading thread's reply

         * and let it get stuck in select()/poll().

         * So a thread may read if either:

         * - There is no other thread that wants to read (the above situation

         *   did not occur).

         * - It is the reading thread (above situation occurred).

         */

        int may_read = c->in.reading == 1 || !count;

#if USE_POLL

        if(may_read && (fd.revents & POLLIN) != 0)

#else

        if(may_read && FD_ISSET(c->fd, &rfds))

#endif

            ret = ret && _xcb_in_read(c);

#if USE_POLL

        if((fd.revents & POLLOUT) != 0)

#else

        if(FD_ISSET(c->fd, &wfds))

#endif

            ret = ret && write_vec(c, vector, count);

    }

    if(count)

        --c->out.writing;

    --c->in.reading;

    return ret;

}