/*
**  L2 - OSSP Logging Library
**  Copyright (c) 2001 The OSSP Project (http://www.ossp.org/)
**  Copyright (c) 2001 Cable & Wireless Deutschland (http://www.cw.com/de/)
**
**  This file is part of OSSP L2, a flexible logging library which
**  can be found at http://www.ossp.org/pkg/l2/.
**
**  Permission to use, copy, modify, and distribute this software for
**  any purpose with or without fee is hereby granted, provided that
**  the above copyright notice and this permission notice appear in all
**  copies.
**
**  THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
**  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
**  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
**  IN NO EVENT SHALL THE AUTHORS AND COPYRIGHT HOLDERS AND THEIR
**  CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
**  SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
**  LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
**  USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
**  ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
**  OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
**  OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
**  SUCH DAMAGE.
**
**  l2_ch_pipe.c: pipe channel implementation
*/

#include "l2.h"

#include <unistd.h>
#include <signal.h>

/* declare private channel configuration */
typedef struct {
    int iPipe; /* pipe filedescriptor used for writing only */
} l2_ch_pipe_t;

static void catchsignal(int sig, ...)
{
    va_list ap;
    static l2_context_t *ctx = NULL;

    va_start(ap, sig);
    if (sig == 0)
        ctx = va_arg(ap, l2_context_t *);
    else if (sig == SIGCHLD) {
        ((l2_ch_pipe_t *)(int *)ctx->vp)->iPipe = -1; /* TODO: Fill in with new pipe fd */
    }
    else if (sig == SIGPIPE)
        ((l2_ch_pipe_t *)(int *)ctx->vp)->iPipe = -1;
    va_end(ap);
}

/* create channel */
static l2_result_t hook_create(l2_context_t *ctx, l2_channel_t *ch)
{
    l2_ch_pipe_t *cfg;

    /* allocate private channel configuration */
    if ((cfg = (l2_ch_pipe_t *)malloc(sizeof(l2_ch_pipe_t))) == NULL)
        return L2_ERR_ARG;

    /* initialize configuration with reasonable defaults */
    cfg->iPipe = -1; 

    /* link private channel configuration into channel context */
    ctx->vp = cfg;

    return L2_OK;
}

/* configure channel */
static l2_result_t hook_configure(l2_context_t *ctx, l2_channel_t *ch, const char *fmt, va_list ap)
{
    l2_ch_pipe_t *cfg = (l2_ch_pipe_t *)ctx->vp;
    l2_param_t pa[2]; 
    l2_result_t rv;

    /* feed and call generic parameter parsing engine */
    L2_PARAM_SET(pa[0], pipe, INT, &cfg->iPipe);
    L2_PARAM_END(pa[1]);
    rv = l2_util_setparams(pa, fmt, ap);

    /* validate the pipe fd */
    if (cfg->iPipe == -1)
        return L2_ERR_ARG;

    catchsignal(0, ctx); /* initialize signal handler with incoming context */
    signal(SIGCHLD, (void(*)())catchsignal); /* pipe changes descriptor     */
    signal(SIGPIPE, (void(*)())catchsignal); /* pipe closes reading fd      */

    return rv;
}

/* write to channel */
static l2_result_t hook_write(l2_context_t *ctx, l2_channel_t *ch,
                              l2_level_t level, const char *buf, size_t buf_size)
{
    l2_ch_pipe_t *cfg = (l2_ch_pipe_t *)ctx->vp;
    l2_channel_t *downstream = l2_channel_downstream(ch);
    l2_result_t rv;
    
    /* validate the pipe fd */
    if (cfg->iPipe == -1)
        return L2_ERR_ARG;

    /* write message to channel pipe */
    if (write(cfg->iPipe, buf, buf_size) == -1)
        return L2_ERR_SYS;

    /* write to downstream channel */
    if ((rv = l2_channel_write(downstream, level, buf, buf_size)) != L2_OK)
        return rv;

    return L2_OK;
}

/* close channel */
static l2_result_t hook_close(l2_context_t *ctx, l2_channel_t *ch)
{
    l2_ch_pipe_t *cfg = (l2_ch_pipe_t *)ctx->vp;
    l2_channel_t *downstream = l2_channel_downstream(ch);
    l2_result_t rv;
    
    /* close channel pipe */
    close(cfg->iPipe);
    cfg->iPipe = -1;

    /* close downstream channel, too */
    if ((rv = l2_channel_close(downstream)) != L2_OK)
        return rv;

    return L2_OK;
}

/* destroy channel */
static l2_result_t hook_destroy(l2_context_t *ctx, l2_channel_t *ch)
{
    l2_ch_pipe_t *cfg = (l2_ch_pipe_t *)ctx->vp;
    l2_channel_t *downstream = l2_channel_downstream(ch);
    l2_result_t rv;

    /* destroy channel configuration */
    free(cfg);

    /* destroy downstream channel, too */
    if ((rv = l2_channel_destroy(downstream)) != L2_OK)
        return rv;

    return L2_OK;
}

/* exported channel handler structure */
l2_handler_t l2_handler_pipe = {
    L2_CHANNEL_FILTER,
    hook_create,
    hook_configure,
    NULL,
    hook_write,
    NULL,
    hook_close,
    hook_destroy
};