/*
   log.c - logging funtions

   Copyright (C) 2002, 2003, 2008, 2010, 2011, 2012, 2013 Arthur de Jong

   This library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   This library 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
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with this library; if not, write to the Free Software
   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
   02110-1301 USA
*/

#include "config.h"

#include <systemd/sd-daemon.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <unistd.h>
#include <syslog.h>
#include <stdarg.h>
#include <errno.h>
#include <string.h>
#include <time.h>
#include <pthread.h>
#include <strings.h>

#include "log.h"

#define MAX_REQUESTID_LENGTH 40

#ifdef TLS

/* the session id that is set for this thread */
static TLS char *sessionid = NULL;

/* the request identifier that is set for this thread */
static TLS char *requestid = NULL;

#else /* no TLS, use pthreads */

static pthread_once_t tls_init_once = PTHREAD_ONCE_INIT;
static pthread_key_t sessionid_key;
static pthread_key_t requestid_key;

static void tls_init_keys(void)
{
  pthread_key_create(&sessionid_key, NULL);
  pthread_key_create(&requestid_key, NULL);
}

#endif /* no TLS, use pthreads */

static char *loglevel2sd(int pri) {
  switch(pri) {
  case LOG_EMERG:   return SD_EMERG;
  case LOG_ALERT:   return SD_ALERT;
  case LOG_CRIT:    return SD_CRIT;
  case LOG_ERR:     return SD_ERR;
  case LOG_WARNING: return SD_WARNING;
  case LOG_NOTICE:  return SD_NOTICE;
  case LOG_INFO:    return SD_INFO;
  case LOG_DEBUG:   return SD_DEBUG;
  }
  return "<?>";
}

/* indicate that we should clear any session identifiers set by
   log_newsession */
void log_clearsession(void)
{
#ifndef TLS
  char *sessionid, *requestid;
  pthread_once(&tls_init_once, tls_init_keys);
  sessionid = pthread_getspecific(sessionid_key);
  requestid = pthread_getspecific(requestid_key);
#endif /* no TLS */
  /* set the session id to empty */
  if (sessionid != NULL)
    sessionid[0] = '\0';
  /* set the request id to empty */
  if (requestid != NULL)
    requestid[0] = '\0';
}

/* indicate that a session id should be included in the output
   and set it to a new value */
void log_newsession(void)
{
#ifndef TLS
  char *sessionid, *requestid;
  pthread_once(&tls_init_once, tls_init_keys);
  sessionid = pthread_getspecific(sessionid_key);
  requestid = pthread_getspecific(requestid_key);
#endif /* no TLS */
  /* ensure that sessionid can hold a string */
  if (sessionid == NULL)
  {
    sessionid = (char *)malloc(7);
    if (sessionid == NULL)
    {
      fprintf(stderr, SD_ERR "malloc() failed: %s", strerror(errno));
      return; /* silently fail */
    }
#ifndef TLS
    pthread_setspecific(sessionid_key, sessionid);
#endif /* no TLS */
  }
  sprintf(sessionid, "%06x", (int)(rand() & 0xffffff));
  /* set the request id to empty */
  if (requestid != NULL)
    requestid[0] = '\0';
}

/* indicate that a request identifier should be included in the output
   from this point on, until log_newsession() is called */
void log_setrequest(const char *format, ...)
{
  va_list ap;
#ifndef TLS
  char *requestid;
  pthread_once(&tls_init_once, tls_init_keys);
  requestid = pthread_getspecific(requestid_key);
#endif /* no TLS */
  /* ensure that requestid can hold a string */
  if (requestid == NULL)
  {
    requestid = (char *)malloc(MAX_REQUESTID_LENGTH);
    if (requestid == NULL)
    {
      fprintf(stderr, SD_ERR "malloc() failed: %s", strerror(errno));
      return; /* silently fail */
    }
#ifndef TLS
    pthread_setspecific(requestid_key, requestid);
#endif /* no TLS */
  }
  /* make the message */
  va_start(ap, format);
  vsnprintf(requestid, MAX_REQUESTID_LENGTH, format, ap);
  requestid[MAX_REQUESTID_LENGTH - 1] = '\0';
  va_end(ap);
}

/* log the given message using the configured logging method */
void log_log(int pri, const char *format, ...)
{
  char *msg = NULL;
  char *tmp = NULL;
  va_list ap;
#ifndef TLS
  char *sessionid, *requestid;
  pthread_once(&tls_init_once, tls_init_keys);
  sessionid = pthread_getspecific(sessionid_key);
  requestid = pthread_getspecific(requestid_key);
#endif /* no TLS */
  /* make the message */
  va_start(ap, format);
  if (vasprintf(&msg, format, ap) < 0) {
    fprintf(stderr, SD_ERR "vasprintf() failed: %s", strerror(errno));
    return;
  }
  va_end(ap);
  if (errno != 0) {
    if (asprintf(&tmp, "%s: %s", msg, strerror(errno)) < 0) {
      fprintf(stderr, SD_ERR "asprintf() failed: %s", strerror(errno));
    } else {
      free(msg);
      msg = tmp;
      errno = 0;
    }
  }

  /* do the logging */
  if ((requestid != NULL) && (requestid[0] != '\0'))
    fprintf(stderr, "%s[sess:%s] <req:%s> %s\n", loglevel2sd(pri), sessionid, requestid, msg);
  else if ((sessionid != NULL) && (sessionid[0] != '\0'))
    fprintf(stderr, "%s[sess:%s] %s\n", loglevel2sd(pri), sessionid, msg);
  else
    fprintf(stderr, "%s%s\n", loglevel2sd(pri), msg);
  fflush(stderr);

  free(msg);
}