/*
* This file is part of the Distributed Network Block Device 3
*
* Copyright(c) 2011-2012 Simon Rettberg
*
* This file may be licensed under the terms of of the
* GNU General Public License Version 2 (the ``GPL'').
*
* Software distributed under the License is distributed
* on an ``AS IS'' basis, WITHOUT WARRANTY OF ANY KIND, either
* express or implied. See the GPL for the specific language
* governing rights and limitations.
*
* You should have received a copy of the GPL along with this
* program. If not, go to http://www.gnu.org/licenses/gpl.html
* or write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*
*/
#include <stdarg.h>
#include <pthread.h>
#include <time.h>
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <stdint.h>
#include "locks.h"
#define MAX(a,b) (a > b ? a : b)
static pthread_spinlock_t logLock;
#define LINE_LEN 500
#define LINE_COUNT 50
typedef struct
{
uint16_t len;
char text[LINE_LEN];
} LogLine;
// This will be used as a ring buffer
static volatile LogLine *logBuffer = NULL;
// bufferPos counts up, use modulo LINE_COUNT to get array index
static volatile int bufferPos = 0;
void initmemlog()
{
// Use main spinlock to make sure we really init only once
if (logBuffer) return;
spin_init(&logLock, PTHREAD_PROCESS_PRIVATE);
logBuffer = (LogLine *)calloc(LINE_COUNT, sizeof(LogLine));
}
void memlogf(const char *fmt, ...)
{
if (!logBuffer) return; // Not initialized yet
va_list ap;
int ret;
time_t rawtime;
struct tm *timeinfo;
time(&rawtime);
timeinfo = localtime(&rawtime);
spin_lock(&logLock);
LogLine *const line = (LogLine *)&(logBuffer[bufferPos % LINE_COUNT]);
const size_t offset = strftime(line->text, LINE_LEN, "[%d.%m. %H:%M:%S] ", timeinfo);
if (offset == 0) *line->text = '\0';
va_start(ap, fmt);
ret = vsnprintf(line->text + offset, LINE_LEN - offset, fmt, ap);
va_end(ap);
char *end = line->text + strlen(line->text);
while (end > line->text && *--end == '\n') *end = '\0'; // remove trailing \n
// glibc 2.0 would return -1 if the buffer was too small
// glibc 2.1 would return the number of bytes required if the buffer was too small
// so to be safe either way, let strlen do the job
line->len = strlen(line->text);
if (ret > 0 || line->len > 0) ++bufferPos;
spin_unlock(&logLock);
puts(line->text);
}
char *fetchlog(int maxlines)
{
if (!logBuffer) return NULL;
if (maxlines <= 0 || maxlines > LINE_COUNT) maxlines = LINE_COUNT;
const int start = MAX(0, bufferPos - maxlines);
int len = 1, i;
//printf("Outputting log from %d to %d\n", start, bufferPos);
spin_lock(&logLock);
// Determine required buffer space for all log lines
for (i = start; i < bufferPos; ++i)
{
if (logBuffer[i % LINE_COUNT].len > 0)
{
len += logBuffer[i % LINE_COUNT].len + 1;
}
}
//printf("Have to allocate %d bytes\n", len);
// Allocate buffer. If this is a bottleneck because of malloc, consider passing a buffer to the function that the caller allocates on the stack
char *retval = (char *)calloc(len, sizeof(char));
if (retval == NULL) goto endFunction;
// Concatenate all log lines, delimit using '\n'
char *pos = retval;
for (i = start; i < bufferPos; ++i)
{
LogLine *const line = (LogLine *)&(logBuffer[i % LINE_COUNT]);
if (line->len > 0)
{
memcpy(pos, (char *)line->text, line->len);
pos += line->len;
*pos++ = '\n';
}
}
*pos = '\0';
endFunction:
spin_unlock(&logLock);
return retval;
}
