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+ /*
+ ** 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
+ };
+
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