Fetches snmp data into rrd files
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/***************************************************************************
* Copyright (C) 03/2010 by Olaf Rempel *
* razzor@kopf-tisch.de *
* *
* This program is free software; you can redistribute it and/or modify *
* it under the terms of the GNU General Public License as published by *
* the Free Software Foundation; version 2 of the License *
* *
* This program is distributed in the hope that it will be useful, *
* but WITHOUT ANY WARRANTY; without even the implied warranty of *
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
* GNU General Public License for more details. *
* *
* You should have received a copy of the GNU General Public License *
* along with this program; if not, write to the *
* Free Software Foundation, Inc., *
* 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. *
***************************************************************************/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <stdarg.h>
#include "linebuffer.h"
#define MIN(a,b) (((a) < (b)) ? (a) : (b))
struct lbuf {
size_t size;
size_t pos;
char *token;
char data[0];
};
/*
* creates linebuffer with given size
*/
struct lbuf * lbuf_create(size_t size)
{
struct lbuf *buf = malloc(sizeof(struct lbuf) + size);
if (buf == NULL)
return NULL;
buf->size = size;
buf->pos = 0;
return buf;
}
/*
* frees the linebuffer and all data in it
*/
void lbuf_free(struct lbuf *buf)
{
free(buf);
}
/*
* clears the linebuffer
* - returns the datasize it was holding
*/
int lbuf_clear(struct lbuf *buf)
{
int oldpos = buf->pos;
buf->pos = 0;
return oldpos;
}
/*
* get pointer to internal data
* - returns pointer to datasize
*/
char * lbuf_getdata(struct lbuf *buf, size_t *len)
{
if (len != NULL)
*len = buf->pos;
return buf->data;
}
/*
* appends data to the buffer
* - returns the number of bytes copied
*/
int lbuf_append(struct lbuf *buf, const char *src, size_t size)
{
int len = MIN(buf->size - buf->pos, size);
memcpy(buf->data + buf->pos, src, len);
buf->pos += len;
return len;
}
/*
* reads as much data as it can get from a FD
* - returns the number of bytes read, or -1 on error
*/
int lbuf_readfd(struct lbuf *buf, int fd)
{
int len = read(fd, buf->data + buf->pos, buf->size - buf->pos);
if (len <= 0)
return -1;
buf->pos += len;
return len;
}
/*
* parses as much data as it can get from a FD
* parses means: backspaces remove one byte from the end of the buffer
* - returns 0 on success, or -1 on error
*/
int lbuf_parsefd(struct lbuf *buf, int fd)
{
char tmp[32];
int len = read(fd, tmp, sizeof(tmp));
if (len <= 0)
return -1;
int i;
for (i = 0; i < len; i++) {
/* "understand" backspace */
if (tmp[i] == 0x08 && buf->pos > 0) {
buf->pos--;
/* copy */
} else if (tmp[i] >= ' ' || tmp[i] == '\n') {
*(buf->data + buf->pos++) = tmp[i];
}
if (buf->pos > buf->size)
return -1;
}
/* TODO: return bytes appended to buffer? */
return 0;
}
/*
* writes as much data as it can to a FD
* - returns the number of bytes written, or -1 on error
*/
int lbuf_writefd(struct lbuf *buf, int fd)
{
int len = write(fd, buf->data, buf->pos);
if (len <= 0)
return -1;
/* handle partial writes */
if (len != buf->pos)
memmove(buf->data, buf->data + len, buf->pos - len);
buf->pos -= len;
return len;
}
/*
* append va_list to buffer
* - returns number ob bytes appended, or -1 on error
*/
int lbuf_vprintf(struct lbuf *buf, const char *fmt, va_list az)
{
int len = vsnprintf(buf->data + buf->pos, buf->size - buf->pos, fmt, az);
if (len < 0 || len >= (buf->size - buf->pos))
return -1;
buf->pos += len;
return len;
}
/*
* printf into buffer
* - returns number of bytes appended, or -1 on error
*/
int lbuf_printf(struct lbuf *buf, const char *fmt, ...)
{
va_list az;
va_start(az, fmt);
int ret = lbuf_vprintf(buf, fmt, az);
va_end(az);
return ret;
}
/*
* get next non-empty token
* - returns pointer to next token
* - returns NULL if no delimter is found in buffer
*/
char * lbuf_gettok(struct lbuf *buf, const char *delim)
{
char *start = buf->data;
char *end = buf->data + buf->pos;
int dlen = strlen(delim);
while (1) {
buf->token = NULL;
/* find first delimiter in buffer */
int i;
for (i = 0; i < dlen; i++) {
char *tok = memchr(start, delim[i], end - start);
if (tok != NULL && (tok < buf->token || buf->token == NULL))
buf->token = tok;
}
/* nothing found */
if (buf->token == NULL)
return NULL;
/* delimter found on start pos -> skip empty token */
if (buf->token == start) {
start++;
if (start >= end)
return NULL;
} else {
/* non-empty token found, exit */
break;
}
}
/* overwrite token, return start ptr */
*(buf->token) = '\0';
return start;
}
/*
* release previous fetched line
* - returns number of remaining bytes in buffer
*/
int lbuf_freetok(struct lbuf *buf)
{
if (buf->token != NULL) {
buf->pos -= (buf->token - buf->data) +1;
memmove(buf->data, buf->token +1, buf->pos);
buf->token = NULL;
}
return buf->pos;
}