ossp-pkg/l2/l2_ch_file.c
1.27
/*
** OSSP l2 - Flexible Logging
** Copyright (c) 2001-2003 Cable & Wireless Deutschland GmbH
** Copyright (c) 2001-2003 The OSSP Project (http://www.ossp.org/)
** Copyright (c) 2001-2003 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>
/* declare private channel configuration */
typedef struct {
int fd;
char *path;
int append;
int trunc;
int perm;
} l2_ch_file_t;
/* 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);
/* 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[5];
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_END(pa[4]);
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;
int mode;
mode_t mask;
/* "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 a path was set */
if (cfg->path == NULL)
return L2_ERR_USE;
/* open channel file */
mode = O_WRONLY|O_CREAT;
if (cfg->trunc == 1)
mode |= O_TRUNC;
else
mode |= O_APPEND;
mask = umask(0);
cfg->fd = open(cfg->path, mode, cfg->perm);
umask(mask);
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;
/* write message to channel file */
if (write(cfg->fd, buf, buf_size) == -1)
return L2_ERR_SYS;
return L2_OK;
}
/* 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
};