LinuxQuestions.org - dns bind source

Here is the source code for bind9.3
can you help me find out the function that gets the DNS requests from the clients and where it is printing the logs based on ip address?here is the source
/*
* Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
* Copyright (c) 1996-1999 by Internet Software Consortium.
*
* 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.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
* OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/

#if !defined(LINT) && !defined(CODECENTER)
static const char rcsid[] = "$Id: logging.c,v 1.3.2.1.4.2 2004/03/17 01:49:42 marka Exp $";
#endif /* not lint */

#include "port_before.h"

#include <sys/types.h>
#include <sys/time.h>
#include <sys/stat.h>

#include <fcntl.h>
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdarg.h>
#include <syslog.h>
#include <errno.h>
#include <time.h>
#include <unistd.h>

#include <isc/assertions.h>
#include <isc/logging.h>
#include <isc/memcluster.h>
#include <isc/misc.h>

#include "port_after.h"

#ifdef VSPRINTF_CHAR
# define VSPRINTF(x) strlen(vsprintf/**/x)
#else
# define VSPRINTF(x) ((size_t)vsprintf x)
#endif

#include "logging_p.h"
documentation
static const int syslog_priority[] = { LOG_DEBUG, LOG_INFO, LOG_NOTICE,
LOG_WARNING, LOG_ERR, LOG_CRIT };

static const char *months[] = { "Jan", "Feb", "Mar", "Apr", "May", "Jun",
"Jul", "Aug", "Sep", "Oct", "Nov", "Dec" };

static const char *level_text[] = {
"info: ", "notice: ", "warning: ", "error: ", "critical: "
};

static void
version_rename(log_channel chan) {
unsigned,, int ver;
char old_name[PATH_MAX+1];
char new_name[PATH_MAX+1];

ver = chan->out.file.versions;
if (ver < 1)
return;
if (ver > LOG_MAX_VERSIONS)
ver = LOG_MAX_VERSIONS;
/*
* Need to have room for '.nn' (XXX assumes LOG_MAX_VERSIONS < 100)
*/
if (strlen(chan->out.file.name) > (size_t)(PATH_MAX-3))
return;
for (ver--; ver > 0; ver--) {
sprintf(old_name, "%s.%d", chan->out.file.name, ver-1);
sprintf(new_name, "%s.%d", chan->out.file.name, ver);
(void)isc_movefile(old_name, new_name);
}
sprintf(new_name, "%s.0", chan->out.file.name);
(void)isc_movefile(chan->out.file.name, new_name);
}

FILE *
log_open_stream(log_channel chan) {
FILE *stream;
int fd, flags;
struct stat sb;
int regular;

if (chan == NULL || chan->type != log_file) {
errno = EINVAL;
return (NULL);
}

/*
* Don't open already open streams
*/
if (chan->out.file.stream != NULL)
return (chan->out.file.stream);

if (stat(chan->out.file.name, &sb)< 0) {
if (errno != ENOENT) {
syslog(LOG_ERR,
"log_open_stream: stat of %s failed: %s",
chan->out.file.name, strerror(errno));
chan->flags |= LOG_CHANNEL_BROKEN;
return (NULL);
}
regular = 1;
} else
regular = (sb.st_mode & S_IFREG);

if (chan->out.file.versions) {
if (!regular) {
syslog(LOG_ERR,
"log_open_stream: want versions but %s isn't a regular file",
chan->out.file.name);
chan->flags |= LOG_CHANNEL_BROKEN;
errno = EINVAL;
return (NULL);
}
}

flags = O_WRONLY|O_CREAT|O_APPEND;

if ((chan->flags & LOG_TRUNCATE) != 0) {
if (regular) {
(void)unlink(chan->out.file.name);
flags |= O_EXCL;
} else {
syslog(LOG_ERR,
"log_open_stream: want truncation but %s isn't a regular file",
chan->out.file.name);
chan->flags |= LOG_CHANNEL_BROKEN;
errno = EINVAL;
return (NULL);
}
}

fd = open(chan->out.file.name, flags,
S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP|S_IROTH|S_IWOTH);
if (fd < 0) {
syslog(LOG_ERR,"log_open_stream: open(%s) failed: %s",
chan->out.file.name, strerror(errno));
chan->flags |= LOG_CHANNEL_BROKEN;
return (NULL);
}
stream = fdopen(fd, "a");
if (stream == NULL) {
syslog(LOG_ERR, "log_open_stream: fdopen() failed");
chan->flags |= LOG_CHANNEL_BROKEN;
return (NULL);
}
(void) fchown(fd, chan->out.file.owner, chan->out.file.group);

chan->out.file.stream = stream;
return (stream);
}

int
log_close_stream(log_channel chan) {
FILE *stream;

if (chan == NULL || chan->type != log_file) {
errno = EINVAL;
return (0);
}
stream = chan->out.file.stream;
chan->out.file.stream = NULL;
if (stream != NULL && fclose(stream) == EOF)
return (-1);
return (0);
}

void
log_close_debug_channels(log_context lc) {
log_channel_list lcl;
int i;

for (i = 0; i < lc->num_categories; i++)
for (lcl = lc->categories[i]; lcl != NULL; lcl = lcl->next)
if (lcl->channel->type == log_file &&
lcl->channel->out.file.stream != NULL &&
lcl->channel->flags & LOG_REQUIRE_DEBUG)
(void)log_close_stream(lcl->channel);
}

FILE *
log_get_stream(log_channel chan) {
if (chan == NULL || chan->type != log_file) {
errno = EINVAL;
return (NULL);
}
return (chan->out.file.stream);
}

char *
log_get_filename(log_channel chan) {
if (chan == NULL || chan->type != log_file) {
errno = EINVAL;
return (NULL);
}
return (chan->out.file.name);
}

int
log_check_channel(log_context lc, int level, log_channel chan) {
int debugging, chan_level;

REQUIRE(lc != NULL);

debugging = ((lc->flags & LOG_OPTION_DEBUG) != 0);

/*
* If not debugging, short circuit debugging messages very early.
*/
if (level > 0 && !debugging)
return (0);

if ((chan->flags & (LOG_CHANNEL_BROKEN|LOG_CHANNEL_OFF)) != 0)
return (0);

/* Some channels only log when debugging is on. */
if ((chan->flags & LOG_REQUIRE_DEBUG) && !debugging)
return (0);

/* Some channels use the global level. */
if ((chan->flags & LOG_USE_CONTEXT_LEVEL) != 0) {
chan_level = lc->level;
} else
chan_level = chan->level;

if (level > chan_level)
return (0);

return (1);
}

int
log_check(log_context lc, int category, int level) {
log_channel_list lcl;
int debugging;

REQUIRE(lc != NULL);

debugging = ((lc->flags & LOG_OPTION_DEBUG) != 0);

/*
* If not debugging, short circuit debugging messages very early.
*/
if (level > 0 && !debugging)
return (0);

if (category < 0 || category > lc->num_categories)
category = 0; /* use default */
lcl = lc->categories[category];
if (lcl == NULL) {
category = 0;
lcl = lc->categories[0];
}

for ( /* nothing */; lcl != NULL; lcl = lcl->next) {
if (log_check_channel(lc, level, lcl->channel))
return (1);
}
return (0);
}

void
log_vwrite(log_context lc, int category, int level, const char *format,
va_list args) {
log_channel_list lcl;
int pri, debugging, did_vsprintf = 0;
int original_category;
FILE *stream;
log_channel chan;
struct timeval tv;
struct tm *local_tm;
#ifdef HAVE_TIME_R
struct tm tm_tmp;
#endif
time_t tt;
const char *category_name;
const char *level_str;
char time_buf[256];
char level_buf[256];

REQUIRE(lc != NULL);

debugging = (lc->flags & LOG_OPTION_DEBUG);

/*
* If not debugging, short circuit debugging messages very early.
*/
if (level > 0 && !debugging)
return;

if (category < 0 || category > lc->num_categories)
category = 0; /* use default */
original_category = category;
lcl = lc->categories[category];
if (lcl == NULL) {
category = 0;
lcl = lc->categories[0];
}

/*
* Get the current time and format it.
*/
time_buf[0]='\0';
if (gettimeofday(&tv, NULL) < 0) {
syslog(LOG_INFO, "gettimeofday failed in log_vwrite()");
} else {
tt = tv.tv_sec;
#ifdef HAVE_TIME_R
local_tm = localtime_r(&tt, &tm_tmp);
#else
local_tm = localtime(&tt);
#endif
if (local_tm != NULL) {
sprintf(time_buf, "%02d-%s-%4d %02d:%02d:%02d.%03ld ",
local_tm->tm_mday, months[local_tm->tm_mon],
local_tm->tm_year+1900, local_tm->tm_hour,
local_tm->tm_min, local_tm->tm_sec,
(long)tv.tv_usec/1000);
}
}

/*
* Make a string representation of the current category and level
*/

if (lc->category_names != NULL &&
lc->category_names[original_category] != NULL)
category_name = lc->category_names[original_category];
else
category_name = "";

if (level >= log_critical) {
if (level >= 0) {
sprintf(level_buf, "debug %d: ", level);
level_str = level_buf;
} else
level_str = level_text[-level-1];
} else {
sprintf(level_buf, "level %d: ", level);
level_str = level_buf;
}

/*
* Write the message to channels.
*/
for ( /* nothing */;
l != NULL; lcl = lcl->next) {
chan = lcl->channel;

if (!log_check_channel(lc, level, chan))
continue;

if (!did_vsprintf) {
if (VSPRINTF((lc->buffer, format, args)) >
(size_t)LOG_BUFFER_SIZE) {
syslog(LOG_CRIT,
"memory overrun in log_vwrite()");
exit(1);
}
did_vsprintf = 1;
}

switch (chan->type) {
case log_syslog:
if (level >= log_critical)
pri = (level >= 0) ? 0 : -level;
else
pri = -log_critical;
syslog(chan->out.facility|syslog_priority[pri],
"%s%s%s%s",
(chan->flags & LOG_TIMESTAMP) ? time_buf : "",
(chan->flags & LOG_PRINT_CATEGORY) ?
category_name : "",
(chan->flags & LOG_PRINT_LEVEL) ?
level_str : "",
lc->buffer);
break;
case log_file:
stream = chan->out.file.stream;
if (stream == NULL) {
stream = log_open_stream(chan);
if (stream == NULL)
break;
}
if (chan->out.file.max_size != ULONG_MAX) {
long pos;

pos = ftell(stream);
if (pos >= 0 &&
(unsigned long)pos >
chan->out.file.max_size) {
/*
* try to roll over the log files,
* ignoring all all return codes
* except the open (we don't want
* to write any more anyway)
*/
log_close_stream(chan);
version_rename(chan);
stream = log_open_stream(chan);
if (stream == NULL)
break;
}
}
fprintf(stream, "%s%s%s%s\n",
(chan->flags & LOG_TIMESTAMP) ? time_buf : "",
(chan->flags & LOG_PRINT_CATEGORY) ?
category_name : "",
(chan->flags & LOG_PRINT_LEVEL) ?
level_str : "",
lc->buffer);
fflush(stream);
break;
case log_null:
break;
default:
syslog(LOG_ERR,
"unknown channel type in log_vwrite()");
}
}
}

void
log_write(log_context lc, int category, int level, const char *format, ...) {
va_list args;

va_start(args, format);
log_vwrite(lc, category, level, format, args);
va_end(args);
}

/*
* Functions to create, set, or destroy contexts
*/

int
log_new_context(int num_categories, char **category_names, log_context *lc) {
log_context nlc;

nlc = memget(sizeof (struct log_context));
if (nlc == NULL) {
errno = ENOMEM;
return (-1);
}
nlc->num_categories = num_categories;
nlc->category_names = category_names;
nlc->categories = memget(num_categories * sizeof (log_channel_list));
if (nlc->categories == NULL) {
memput(nlc, sizeof (struct log_context));
errno = ENOMEM;
return (-1);
}
memset(nlc->categories, '\0',
num_categories * sizeof (log_channel_list));
nlc->flags = 0U;
nlc->level = 0;
*lc = nlc;
return (0);
}

void
log_free_context(log_context lc) {
log_channel_list lcl, lcl_next;
log_channel chan;
int i;

REQUIRE(lc != NULL);

for (i = 0; i < lc->num_categories; i++)
for (lcl = lc->categories[i]; lcl != NULL; lcl = lcl_next) {
lcl_next = lcl->next;
chan = lcl->channel;
(void)log_free_channel(chan);
memput(lcl, sizeof (struct log_channel_list));
}
memput(lc->categories,
lc->num_categories * sizeof (log_channel_list));
memput(lc, sizeof (struct log_context));
}

int
log_add_channel(log_context lc, int category, log_channel chan) {
log_channel_list lcl;

if (lc == NULL || category < 0 || category >= lc->num_categories) {
errno = EINVAL;
return (-1);
}

lcl = memget(sizeof (struct log_channel_list));
if (lcl == NULL) {
errno = ENOMEM;
return(-1);
}
lcl->channel = chan;
lcl->next = lc->categories[category];
lc->categories[category] = lcl;
chan->references++;
return (0);
}

int
log_remove_channel(log_context lc, int category, log_channel chan) {
log_channel_list lcl, prev_lcl, next_lcl;
int found = 0;

if (lc == NULL || category < 0 || category >= lc->num_categories) {
errno = EINVAL;
return (-1);
}

for (prev_lcl = NULL, lcl = lc->categories[category];
lcl != NULL;
lcl = next_lcl) {
next_lcl = lcl->next;
if (lcl->channel == chan) {
log_free_channel(chan);
if (prev_lcl != NULL)
prev_lcl->next = next_lcl;
else
lc->categories[category] = next_lcl;
memput(lcl, sizeof (struct log_channel_list));
/*
* We just set found instead of returning because
* the channel might be on the list more than once.
*/
found = 1;
} else
prev_lcl = lcl;
}
if (!found) {
errno = ENOENT;
return (-1);
}
return (0);
}

int
log_option(log_context lc, int option, int value) {
if (lc == NULL) {
errno = EINVAL;
return (-1);
}
switch (option) {
case LOG_OPTION_DEBUG:
if (value)
lc->flags |= option;
else
lc->flags &= ~option;
break;
case LOG_OPTION_LEVEL:
lc->level = value;
break;
default:
errno = EINVAL;
return (-1);
}
return (0);
}

int
log_category_is_active(log_context lc, int category) {
if (lc == NULL) {
errno = EINVAL;
return (-1);
}
if (category >= 0 && category < lc->num_categories &&
lc->categories[category] != NULL)
return (1);
return (0);
}

log_channel
log_new_syslog_channel(unsigned int flags, int level, int facility) {
log_channel chan;

chan = memget(sizeof (struct log_channel));
if (chan == NULL) {
errno = ENOMEM;
return (NULL);
}
chan->type = log_syslog;
chan->flags = flags;
chan->level = level;
chan->out.facility = facility;
chan->references = 0;
return (chan);
}

log_channel
log_new_file_channel(unsigned int flags, int level,
const char *name, FILE *stream, unsigned int versions,
unsigned long max_size) {
log_channel chan;

chan = memget(sizeof (struct log_channel));
if (chan == NULL) {
errno = ENOMEM;
return (NULL);
}
chan->type = log_file;
chan->flags = flags;
chan->level = level;
if (name != NULL) {
size_t len;

len = strlen(name);
/*
* Quantize length to a multiple of 256. There's space for the
* NUL, since if len is a multiple of 256, the size chosen will
* be the next multiple.
*/
chan->out.file.name_size = ((len / 256) + 1) * 256;
chan->out.file.name = memget(chan->out.file.name_size);
if (chan->out.file.name == NULL) {
memput(chan, sizeof (struct log_channel));
errno = ENOMEM;
return (NULL);
}
/* This is safe. */
strcpy(chan->out.file.name, name);
} else {
chan->out.file.name_size = 0;
chan->out.file.name = NULL;
}
chan->out.file.stream = stream;
chan->out.file.versions = versions;
chan->out.file.max_size = max_size;
chan->out.file.owner = getuid();
chan->out.file.group = getgid();
chan->references = 0;
return (chan);
}

int
log_set_file_owner(log_channel chan, uid_t owner, gid_t group) {
if (chan->type != log_file) {
errno = EBADF;
return (-1);
}
chan->out.file.owner = owner;
chan->out.file.group = group;
return (0);
}

log_channel
log_new_null_channel() {
log_channel chan;

chan = memget(sizeof (struct log_channel));
if (chan == NULL) {
errno = ENOMEM;
return (NULL);
}
chan->type = log_null;
chan->flags = LOG_CHANNEL_OFF;
chan->level = log_info;
chan->references = 0;
return (chan);
}

int
log_inc_references(log_channel chan) {
if (chan == NULL) {
errno = EINVAL;
return (-1);
}
chan->references++;
return (0);
}

int
log_dec_references(log_channel chan) {
if (chan == NULL || chan->references <= 0) {
errno = EINVAL;
return (-1);
}
chan->references--;
return (0);
}

log_channel_type
log_get_channel_type(log_channel chan) {
REQUIRE(chan != NULL);

return (chan->type);
}

int
log_free_channel(log_channel chan) {
if (chan == NULL || chan->references <= 0) {
errno = EINVAL;
return (-1);
}
chan->references--;
if (chan->references == 0) {
if (chan->type == log_file) {
if ((chan->flags & LOG_CLOSE_STREAM) &&
chan->out.file.stream != NULL)
(void)fclose(chan->out.file.stream);
if (chan->out.file.name != NULL)
memput(chan->out.file.name,
chan->out.file.name_size);
}
memput(chan, sizeof (struct log_channel));
}
return (0);
}