ossp-pkg/l2/l2_ch_file.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_file.c: file channel implementation
*/
#include "l2.h"
#include <fcntl.h>
#include <unistd.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/stat.h>
/* declare private channel configuration */
typedef struct {
int fd;
char *path;
int append;
int trunc;
int perm;
int jitter;
int jittercount;
int monitor;
long monitortime;
dev_t monitordev;
ino_t monitorino;
} l2_ch_file_t;
/* open channel file */
static void openchfile(l2_context_t *ctx, l2_channel_t *ch, int mode)
{
l2_ch_file_t *cfg = (l2_ch_file_t *)ctx->vp;
mode_t mask;
struct timeval tv;
struct stat st;
#ifdef O_LARGEFILE
/* Support for 1996-03-20 addition to Single UNIX Specification for
* systems that still require the Transitional Extensions to System
* Interfaces to support arbitrary file sizes (LFS >2GiB)
*/
mode |= O_LARGEFILE;
#endif
/* open channel file */
mask = umask(0);
cfg->fd = open(cfg->path, mode, cfg->perm);
umask(mask);
/* prepare jittering counter */
cfg->jittercount = 0;
/* prepare monitoring time and stat */
if (cfg->monitor >= 1) {
if (gettimeofday(&tv, NULL) != -1)
cfg->monitortime = tv.tv_sec;
else
cfg->monitortime = 0;
if ( (cfg->fd != -1)
&& (fstat(cfg->fd, &st) != -1)) {
cfg->monitordev = st.st_dev;
cfg->monitorino = st.st_ino;
}
else {
cfg->monitordev = 0;
cfg->monitorino = 0;
}
}
}
/* create channel */
static l2_result_t hook_create(l2_context_t *ctx, l2_channel_t *ch)
{
l2_ch_file_t *cfg;
/* allocate private channel configuration */
if ((cfg = (l2_ch_file_t *)malloc(sizeof(l2_ch_file_t))) == NULL)
return L2_ERR_ARG;
/* initialize configuration with reasonable defaults */
cfg->fd = -1;
cfg->path = NULL;
cfg->append = -1;
cfg->trunc = -1;
cfg->perm = (S_IRUSR|S_IWUSR|S_IRGRP|S_IROTH);
cfg->jitter = 0;
cfg->jittercount = 0;
cfg->monitor = 0;
cfg->monitortime = 0;
cfg->monitordev = 0;
cfg->monitorino = 0;
/* 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_file_t *cfg = (l2_ch_file_t *)ctx->vp;
l2_param_t pa[7];
l2_result_t rv;
l2_env_t *env;
/* feed and call generic parameter parsing engine */
L2_PARAM_SET(pa[0], path, STR, &cfg->path);
L2_PARAM_SET(pa[1], append, INT, &cfg->append);
L2_PARAM_SET(pa[2], trunc, INT, &cfg->trunc);
L2_PARAM_SET(pa[3], perm, INT, &cfg->perm);
L2_PARAM_SET(pa[4], jitter, INT, &cfg->jitter);
L2_PARAM_SET(pa[5], monitor, INT, &cfg->monitor);
L2_PARAM_END(pa[6]);
l2_channel_env(ch, &env);
rv = l2_util_setparams(env, pa, fmt, ap);
return rv;
}
/* open channel */
static l2_result_t hook_open(l2_context_t *ctx, l2_channel_t *ch)
{
l2_ch_file_t *cfg = (l2_ch_file_t *)ctx->vp;
/* "append" backward compatibility; only cfg->trunc is used in the code
* make sure append/trunc either both use defaults, both are set different, or only one is set
*
* truth table for user input, append, trunc => resulting trunc
* -----------------+------+------+------------------
* -1 -1 0 (default)
* trunc=0 -1 0 0
* trunc=1 -1 1 1
* append=0 0 -1 1
* append=0, trunc=0 0 0 ERROR
* append=0, trunc=1 0 1 1
* append=1 1 -1 0
* append=1, trunc=0 1 0 0
* append=1, trunc=1 1 1 ERROR
*/
if (cfg->append >= 1)
cfg->append = 1; /* reduce to -1 (undef), 0 (no), 1 (yes) */
if (cfg->trunc >= 1)
cfg->trunc = 1; /* reduce to -1 (undef), 0 (no), 1 (yes) */
if ( cfg->append != -1
&& cfg->trunc != -1
&& cfg->append == cfg->trunc) /* collision */
return L2_ERR_USE;
if ( cfg->trunc == -1)
cfg->trunc = (1 - cfg->append) & 1;
/* make sure jitter count is positive number */
if (cfg->jitter < 0)
return L2_ERR_USE;
/* make sure monitor time is positive number */
if (cfg->monitor < 0)
return L2_ERR_USE;
/* make sure a path was set */
if (cfg->path == NULL)
return L2_ERR_USE;
/* open channel file */
if (cfg->trunc == 1)
openchfile(ctx, ch, O_WRONLY|O_CREAT|O_TRUNC);
else
openchfile(ctx, ch, O_WRONLY|O_CREAT|O_APPEND);
if (cfg->fd == -1)
return L2_ERR_SYS;
return L2_OK;
}
/* 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_file_t *cfg = (l2_ch_file_t *)ctx->vp;
l2_result_t rc = L2_OK;
int reopen = 0;
struct timeval tv;
struct stat st;
/* if jittering, count writes and reopen file if jitter threshold is reached or exceeded */
if (cfg->jitter >= 1) {
cfg->jittercount++;
if (cfg->jittercount >= cfg->jitter) {
cfg->jittercount = 0;
reopen = 1;
}
}
/* if monitoring, from time to time check for a renamed log and reopen file on detection */
if (cfg->monitor >= 1) {
int dostat = 0;
if (gettimeofday(&tv, NULL) != -1) {
if ((tv.tv_sec - cfg->monitortime) >= cfg->monitor) {
cfg->monitortime = tv.tv_sec;
dostat = 1;
}
}
else {
dostat = 1;
}
if (dostat == 1) {
if (stat(cfg->path, &st) == -1) {
reopen = 1;
}
else {
if ( (cfg->monitordev != st.st_dev)
|| (cfg->monitorino != st.st_ino)) {
reopen = 1;
}
}
}
}
/* close for reopen if required */
if (reopen == 1 && cfg->fd != -1) {
close(cfg->fd);
cfg->fd = -1;
}
/* open if required */
if (cfg->fd == -1) {
openchfile(ctx, ch, O_WRONLY|O_CREAT|O_APPEND);
}
if (cfg->fd == -1)
return L2_ERR_SYS;
/* write message to channel file */
if (write(cfg->fd, buf, buf_size) == -1)
rc = L2_ERR_SYS;
return rc;
}
/* close channel */
static l2_result_t hook_close(l2_context_t *ctx, l2_channel_t *ch)
{
l2_ch_file_t *cfg = (l2_ch_file_t *)ctx->vp;
/* close channel file */
close(cfg->fd);
cfg->fd = -1;
return L2_OK;
}
/* destroy channel */
static l2_result_t hook_destroy(l2_context_t *ctx, l2_channel_t *ch)
{
l2_ch_file_t *cfg = (l2_ch_file_t *)ctx->vp;
/* destroy channel configuration */
if (cfg->path != NULL)
free(cfg->path);
free(cfg);
return L2_OK;
}
/* exported channel handler structure */
l2_handler_t l2_handler_file = {
"file",
L2_CHANNEL_OUTPUT,
hook_create,
hook_configure,
hook_open,
hook_write,
NULL,
hook_close,
hook_destroy
};
