ossp-pkg/l2/l2_ch_buffer.c
/*
** OSSP l2 - Flexible Logging
** Copyright (c) 2001-2005 Cable & Wireless <http://www.cw.com/>
** Copyright (c) 2001-2005 The OSSP Project <http://www.ossp.org/>
** Copyright (c) 2001-2005 Ralf S. Engelschall <rse@engelschall.com>
**
** This file is part of OSSP l2, a flexible logging library which
** can be found at http://www.ossp.org/pkg/lib/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_buffer.c: buffering channel implementation
*/
#include "l2.h"
#include "l2_p.h" /* for TRACE macro */
#include <string.h>
#include <unistd.h> /* for alarm(3) */
#include <signal.h> /* for sigaction(2) and SIGALRM */
#ifdef HAVE_SYS_TIME_H
#include <sys/time.h> /* for setitimer(2) */
#endif
#define L2_BUFFER_TIMER ITIMER_REAL /* calls to [s|g]etitimer() and alarm() */
/* declare private channel configuration */
typedef struct {
char *buf;
int bufpos;
int bufsize;
long bufinterval;
struct sigaction sigalrm;
#if defined(HAVE_SETITIMER) && defined(HAVE_SYS_TIME_H)
struct itimerval valprev;
#endif
int levelflush;
l2_level_t level;
} l2_ch_buffer_t;
/* Sets the VIRTUAL timer to preconfigured value in cfg */
static int set_alarm(l2_ch_buffer_t *cfg)
{
#if defined(HAVE_SETITIMER) && defined(HAVE_SYS_TIME_H)
struct itimerval valtest, valnew;
/* initialize auto vars before using them */
memset(&valnew, 0, sizeof(valnew));
valnew.it_interval.tv_sec = cfg->bufinterval;
valnew.it_interval.tv_usec = 0;
valnew.it_value.tv_sec = cfg->bufinterval;
valnew.it_value.tv_usec = 0;
if ((getitimer(L2_BUFFER_TIMER, &valtest) == 0) &&
((valtest.it_value.tv_sec | valtest.it_value.tv_usec |
valtest.it_interval.tv_sec | valtest.it_interval.tv_usec) == 0))
return setitimer(L2_BUFFER_TIMER, &valnew, &cfg->valprev);
else {
cfg->bufinterval = -1L; /* mark this timer as broken */
assert(FALSE);
return 1; /* to make the compiler happy */
}
#else
unsigned int uiAlarmed = 0;
assert(uiAlarmed = alarm(cfg->bufinterval));
if (uiAlarmed) { /* check if SIGALRM is occupied */
alarm(uiAlarmed); /* ...if so, then hack in the old value */
cfg->bufinterval = -1L; /* ...mark this timer as broken */
}
return 0;
#endif
}
/* Resets the VIRTUAL timer to preconfigured value in cfg */
static int reset_alarm(l2_ch_buffer_t *cfg)
{
#if defined(HAVE_SETITIMER) && defined(HAVE_SYS_TIME_H)
struct itimerval valnew;
/* initialize auto vars before using them */
memset(&valnew, 0, sizeof(valnew));
valnew.it_interval.tv_sec = cfg->bufinterval;
valnew.it_interval.tv_usec = 0;
valnew.it_value.tv_sec = cfg->bufinterval;
valnew.it_value.tv_usec = 0;
return setitimer(L2_BUFFER_TIMER, &valnew, 0);
#else
alarm(cfg->bufinterval);
return 0;
#endif
}
static void catchsignal(int sig, ...)
{
va_list ap;
static l2_channel_t *ch = NULL;
static l2_ch_buffer_t *cfg = NULL;
if (sig == 0) {
va_start(ap, sig);
ch = va_arg(ap, l2_channel_t *); /* init the handler just like */
cfg = va_arg(ap, l2_ch_buffer_t *); /* Thomas Lotterer does */
va_end(ap);
}
else if (sig == SIGALRM) {
TRACE("SIGALRM caught");
l2_channel_flush(ch);
reset_alarm(cfg); /* alarm(3) doesn't auto-reset like setitime(2) */
}
}
/* create channel */
static l2_result_t hook_create(l2_context_t *ctx, l2_channel_t *ch)
{
l2_ch_buffer_t *cfg;
/* allocate private channel configuration */
if ((cfg = (l2_ch_buffer_t *)malloc(sizeof(l2_ch_buffer_t))) == NULL)
return L2_ERR_MEM;
/* initialize configuration with reasonable defaults */
cfg->buf = NULL;
cfg->bufpos = 0;
cfg->bufsize = 4096;
cfg->bufinterval = 0;
cfg->levelflush = 0;
cfg->level = L2_LEVEL_NONE;
memset(&cfg->sigalrm, 0, sizeof(cfg->sigalrm));
#if defined(HAVE_SETITIMER) && defined(HAVE_SYS_TIME_H)
memset(&cfg->valprev, 0, sizeof(cfg->valprev));
#endif
/* 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_buffer_t *cfg = (l2_ch_buffer_t *)ctx->vp;
l2_param_t pa[4];
l2_result_t rv;
l2_env_t *env;
/* feed and call generic parameter parsing engine */
L2_PARAM_SET(pa[0], size, INT, &cfg->bufsize);
L2_PARAM_SET(pa[1], interval, INT, &cfg->bufinterval);
L2_PARAM_SET(pa[2], levelflush, INT, &cfg->levelflush);
L2_PARAM_END(pa[3]);
l2_channel_env(ch, &env);
rv = l2_util_setparams(env, pa, fmt, ap);
if (cfg->bufinterval == -1L) /* -1 is reserved by L2 */
return L2_ERR_ARG; /* set_alarm() uses it */
if (cfg->bufsize < 0)
return L2_ERR_ARG;
return rv;
}
/* open channel */
static l2_result_t hook_open(l2_context_t *ctx, l2_channel_t *ch)
{
l2_ch_buffer_t *cfg = (l2_ch_buffer_t *)ctx->vp;
struct sigaction locact;
if ((cfg->bufinterval != 0) && (cfg->bufinterval != -1L)) {
/* initialize auto vars before using them */
memset(&locact, 0, sizeof(locact));
locact.sa_handler = (void(*)(int))catchsignal;
sigemptyset(&locact.sa_mask);
locact.sa_flags = 0;
catchsignal(0, ch, (l2_ch_buffer_t *)ctx->vp);
/* save old signal context before replacing with our own */
if (sigaction(SIGALRM, &locact, &cfg->sigalrm) < 0)
return L2_ERR_SYS;
if (set_alarm(cfg)) /* this is our own L2 set_alarm */
return L2_ERR_SYS;
}
/* open channel buffer */
if (cfg->bufsize > 0) {
if ((cfg->buf = malloc(cfg->bufsize)) == NULL)
return L2_ERR_MEM;
cfg->bufpos = 0;
}
return L2_OK_PASS;
}
/* 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_buffer_t *cfg = (l2_ch_buffer_t *)ctx->vp;
l2_channel_t *downstream;
l2_result_t rv;
if (buf_size > (cfg->bufsize - cfg->bufpos)) {
/* flush buffer if necessary */
if (cfg->bufpos > 0) {
downstream = NULL;
while ((rv = l2_channel_downstream(ch, &downstream)) == L2_OK)
if ((rv = l2_channel_write(downstream, cfg->level, cfg->buf, cfg->bufpos)) != L2_OK)
return rv;
cfg->bufpos = 0;
cfg->level = L2_LEVEL_NONE;
}
/* pass through immediately to downstream if still too large */
if (buf_size > cfg->bufsize) {
downstream = NULL;
while ((rv = l2_channel_downstream(ch, &downstream)) == L2_OK)
if ((rv = l2_channel_write(downstream, level, buf, buf_size)) != L2_OK)
return rv;
return L2_OK;
}
}
/* flush if incoming message level differs from those already in buffer */
if ( (cfg->levelflush) /* if different levels force a flush */
&& (cfg->bufpos > 0) /* and there is something in the buffer */
&& (cfg->level != L2_LEVEL_NONE) /* and a remembered level is known */
&& (level != cfg->level) /* and the levels really differ */)
{
downstream = NULL;
while (l2_channel_downstream(ch, &downstream) == L2_OK)
if ((rv = l2_channel_write(downstream, cfg->level, cfg->buf, cfg->bufpos)) != L2_OK)
return rv;
cfg->bufpos = 0;
cfg->level = L2_LEVEL_NONE;
}
/* finally write incoming message to channel buffer */
memcpy(cfg->buf+cfg->bufpos, buf, buf_size);
cfg->bufpos += buf_size;
cfg->level = level;
return L2_OK;
}
/* flush channel */
static l2_result_t hook_flush(l2_context_t *ctx, l2_channel_t *ch)
{
l2_ch_buffer_t *cfg = (l2_ch_buffer_t *)ctx->vp;
l2_channel_t *downstream;
l2_result_t rv;
/* write the buffer contents downstream */
TRACE("l2_ch_buffer hook_flush called\n");
if (cfg->bufpos > 0) {
downstream = NULL;
while (l2_channel_downstream(ch, &downstream) == L2_OK)
if ((rv = l2_channel_write(downstream, cfg->level, cfg->buf, cfg->bufpos)) != L2_OK)
return rv;
cfg->bufpos = 0;
cfg->level = L2_LEVEL_NONE; /* reset this->context->level */
}
/* reset the flush alarm timer to synchronize the buffer */
if ((cfg->bufinterval != 0) && (cfg->bufinterval != -1L))
if (reset_alarm(cfg))
return L2_ERR_SYS;
return L2_OK_PASS;
}
/* close channel */
static l2_result_t hook_close(l2_context_t *ctx, l2_channel_t *ch)
{
l2_ch_buffer_t *cfg = (l2_ch_buffer_t *)ctx->vp;
l2_channel_t *downstream;
l2_result_t rv;
if ((cfg->bufinterval != 0) && (cfg->bufinterval != -1L)) {
#if defined(HAVE_SETITIMER) && defined(HAVE_SYS_TIME_H)
if (setitimer(L2_BUFFER_TIMER, &cfg->valprev, 0)) /* restore timer */
return L2_ERR_SYS;
#else
alarm(0);
#endif
/* restore previous signal context if previously saved & replaced */
if (&cfg->sigalrm.sa_handler)
if (sigaction(SIGALRM, &cfg->sigalrm, 0) < 0)
rv = L2_ERR_SYS;
}
/* write pending data before closing down */
if (cfg->bufpos > 0) {
downstream = NULL;
while (l2_channel_downstream(ch, &downstream) == L2_OK)
if ((rv = l2_channel_write(downstream, cfg->level, cfg->buf, cfg->bufpos)) != L2_OK)
return rv;
cfg->bufpos = 0;
cfg->level = L2_LEVEL_NONE; /* reset this->context->level */
}
/* close channel buffer */
if (cfg->buf != NULL) {
free(cfg->buf);
cfg->buf = NULL;
}
return L2_OK_PASS;
}
/* destroy channel */
static l2_result_t hook_destroy(l2_context_t *ctx, l2_channel_t *ch)
{
l2_ch_buffer_t *cfg = (l2_ch_buffer_t *)ctx->vp;
/* destroy channel configuration */
if (cfg->buf != NULL)
free(cfg->buf);
free(cfg);
return L2_OK_PASS;
}
/* exported channel handler structure */
l2_handler_t l2_handler_buffer = {
"buffer",
L2_CHANNEL_FILTER,
hook_create,
hook_configure,
hook_open,
hook_write,
hook_flush,
hook_close,
hook_destroy
};
