ossp-pkg/l2/l2_ch_pipe.c
1.10
/*
** 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
};