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/* Copyright (c) 2001 Matej Pfajfar.
* Copyright (c) 2001-2004, Roger Dingledine.
* Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson. */
/* See LICENSE for licensing information */
/* $Id$ */
const char log_c_id[] = "$Id$";
/**
* \file log.c
* \brief Functions to send messages to log files or the console.
**/
#include "orconfig.h"
#include <stdarg.h>
#include <assert.h>
#include <stdlib.h>
#include <string.h>
#ifdef HAVE_SYS_TIME_H
#include <sys/time.h>
#endif
#ifdef HAVE_TIME_H
#include <time.h>
#endif
#include "./util.h"
#include "./log.h"
#ifdef HAVE_EVENT_H
#include <event.h>
#else
#error "Tor requires libevent to build."
#endif
#define TRUNCATED_STR "[...truncated]"
#define TRUNCATED_STR_LEN 14
/** Information for a single logfile; only used in log.c */
typedef struct logfile_t {
struct logfile_t *next; /**< Next logfile_t in the linked list. */
char *filename; /**< Filename to open. */
FILE *file; /**< Stream to receive log messages. */
int needs_close; /**< Boolean: true if the stream gets closed on shutdown. */
int min_loglevel; /**< Lowest severity level to send to this stream. */
int max_loglevel; /**< Highest severity level to send to this stream. */
int is_temporary; /**< Boolean: close after initializing logging subsystem.*/
int is_syslog; /**< Boolean: send messages to syslog. */
log_callback callback; /**< If not NULL, send messages to this function. */
} logfile_t;
/** Helper: map a log severity to descriptive string. */
static INLINE const char *
sev_to_string(int severity)
{
switch (severity) {
case LOG_DEBUG: return "debug";
case LOG_INFO: return "info";
case LOG_NOTICE: return "notice";
case LOG_WARN: return "warn";
case LOG_ERR: return "err";
default: assert(0); return "UNKNOWN";
}
}
/** Linked list of logfile_t. */
static logfile_t *logfiles = NULL;
#ifdef HAVE_SYSLOG_H
static int syslog_count = 0;
#endif
static void delete_log(logfile_t *victim);
static void close_log(logfile_t *victim);
/** Helper: Write the standard prefix for log lines to a
* <b>buf_len</b> character buffer in <b>buf</b>.
*/
static INLINE size_t
_log_prefix(char *buf, size_t buf_len, int severity)
{
time_t t;
struct timeval now;
struct tm tm;
size_t n;
int r;
tor_gettimeofday(&now);
t = (time_t)now.tv_sec;
n = strftime(buf, buf_len, "%b %d %H:%M:%S", tor_localtime_r(&t, &tm));
r = tor_snprintf(buf+n, buf_len-n,
".%.3ld [%s] ",
(long)now.tv_usec / 1000, sev_to_string(severity));
if (r<0)
return buf_len-1;
else
return n+r;
}
/** If lf refers to an actual file that we have just opened, and the file
* contains no data, log an "opening new logfile" message at the top.
*
* Return -1 if the log is broken and needs to be deleted, else return 0.
*/
static int
log_tor_version(logfile_t *lf, int reset)
{
char buf[256];
size_t n;
int is_new;
if (!lf->needs_close)
/* If it doesn't get closed, it isn't really a file. */
return 0;
if (lf->is_temporary)
/* If it's temporary, it isn't really a file. */
return 0;
#ifdef HAVE_FTELLO
is_new = (ftello(lf->file) == 0);
#else
is_new = (ftell(lf->file) == 0);
#endif
if (reset && !is_new)
/* We are resetting, but we aren't at the start of the file; no
* need to log again. */
return 0;
n = _log_prefix(buf, sizeof(buf), LOG_NOTICE);
tor_snprintf(buf+n, sizeof(buf)-n,
"Tor %s opening %slog file.\n", VERSION, is_new?"new ":"");
if (fputs(buf, lf->file) == EOF ||
fflush(lf->file) == EOF) /* error */
return -1; /* failed */
return 0;
}
/** Helper: Format a log message into a fixed-sized buffer. (This is
* factored out of <b>logv</b> so that we never format a message more
* than once.) Return a pointer to the first character of the message
* portion of the formatted string.
*/
static INLINE char *
format_msg(char *buf, size_t buf_len,
int severity, const char *funcname,
const char *format, va_list ap)
{
size_t n;
int r;
char *end_of_prefix;
tor_assert(buf_len >= 2); /* prevent integer underflow */
buf_len -= 2; /* subtract 2 characters so we have room for \n\0 */
n = _log_prefix(buf, buf_len, severity);
end_of_prefix = buf+n;
if (funcname) {
r = tor_snprintf(buf+n, buf_len-n, "%s(): ", funcname);
if (r<0)
n = strlen(buf);
else
n += r;
}
r = tor_vsnprintf(buf+n,buf_len-n,format,ap);
if (r < 0) {
/* The message was too long; overwrite the end of the buffer with
* "[...truncated]" */
if (buf_len >= TRUNCATED_STR_LEN) {
int offset = buf_len-TRUNCATED_STR_LEN;
/* We have an extra 2 characters after buf_len to hold the \n\0,
* so it's safe to add 1 to the size here. */
strlcpy(buf+offset, TRUNCATED_STR, buf_len-offset+1);
}
/* Set 'n' to the end of the buffer, where we'll be writing \n\0.
* Since we already subtracted 2 from buf_len, this is safe.*/
n = buf_len;
} else {
n += r;
}
buf[n]='\n';
buf[n+1]='\0';
return end_of_prefix;
}
/** Helper: sends a message to the appropriate logfiles, at loglevel
* <b>severity</b>. If provided, <b>funcname</b> is prepended to the
* message. The actual message is derived as from tor_snprintf(format,ap).
*/
static void
logv(int severity, uint32_t domain, const char *funcname, const char *format,
va_list ap)
{
char buf[10024];
int formatted = 0;
logfile_t *lf;
char *end_of_prefix=NULL;
assert(format);
lf = logfiles;
while (lf) {
if (severity > lf->min_loglevel || severity < lf->max_loglevel) {
lf = lf->next;
continue;
}
if (! (lf->file || lf->is_syslog || lf->callback)) {
lf = lf->next;
continue;
}
if (!formatted) {
end_of_prefix =
format_msg(buf, sizeof(buf), severity, funcname, format, ap);
formatted = 1;
}
if (lf->is_syslog) {
#ifdef HAVE_SYSLOG_H
syslog(severity, "%s", end_of_prefix);
#endif
lf = lf->next;
continue;
} else if (lf->callback) {
lf->callback(severity, domain, end_of_prefix);
lf = lf->next;
continue;
}
if (fputs(buf, lf->file) == EOF ||
fflush(lf->file) == EOF) { /* error */
/* don't log the error! Blow away this log entry and continue. */
logfile_t *victim = lf;
lf = victim->next;
delete_log(victim);
} else {
lf = lf->next;
}
}
}
/** Output a message to the log. */
void
_log(int severity, uint32_t domain, const char *format, ...)
{
va_list ap;
va_start(ap,format);
logv(severity, domain, NULL, format, ap);
va_end(ap);
}
/** Output a message to the log, prefixed with a function name <b>fn</b>. */
#ifdef __GNUC__
void
_log_fn(int severity, uint32_t domain, const char *fn, const char *format, ...)
{
va_list ap;
va_start(ap,format);
logv(severity, domain, fn, format, ap);
va_end(ap);
}
#else
const char *_log_fn_function_name=NULL;
void
_log_fn(int severity, uint32_t domain, const char *format, ...)
{
va_list ap;
va_start(ap,format);
logv(severity, domain, _log_fn_function_name, format, ap);
va_end(ap);
_log_fn_function_name = NULL;
}
void
debug(uint32_t domain, const char *format, ...)
{
va_list ap;
va_start(ap,format);
logv(LOG_DEBUG, domain, NULL, format, ap);
va_end(ap);
_log_fn_function_name = NULL;
}
void
info(uint32_t domain, const char *format, ...)
{
va_list ap;
va_start(ap,format);
logv(LOG_INFO, domain, NULL, format, ap);
va_end(ap);
_log_fn_function_name = NULL;
}
void
notice(uint32_t domain, const char *format, ...)
{
va_list ap;
va_start(ap,format);
logv(LOG_NOTICE, domain, NULL, format, ap);
va_end(ap);
_log_fn_function_name = NULL;
}
void
warn(uint32_t domain, const char *format, ...)
{
va_list ap;
va_start(ap,format);
logv(LOG_WARN, domain, NULL, format, ap);
va_end(ap);
_log_fn_function_name = NULL;
}
void
err(uint32_t domain, const char *format, ...)
{
va_list ap;
va_start(ap,format);
logv(LOG_ERR, domain, NULL, format, ap);
va_end(ap);
_log_fn_function_name = NULL;
}
#endif
/** Close all open log files. */
void
close_logs(void)
{
logfile_t *victim;
while (logfiles) {
victim = logfiles;
logfiles = logfiles->next;
close_log(victim);
tor_free(victim->filename);
tor_free(victim);
}
}
/** Remove and free the log entry <b>victim</b> from the linked-list
* logfiles (it must be present in the list when this function is
* called). After this function is called, the caller shouldn't refer
* to <b>victim</b> anymore.
*/
static void
delete_log(logfile_t *victim)
{
logfile_t *tmpl;
if (victim == logfiles)
logfiles = victim->next;
else {
for (tmpl = logfiles; tmpl && tmpl->next != victim; tmpl=tmpl->next) ;
tor_assert(tmpl);
tor_assert(tmpl->next == victim);
tmpl->next = victim->next;
}
tor_free(victim->filename);
tor_free(victim);
}
/** Helper: release system resources (but not memory) held by a single
* logfile_t. */
static void
close_log(logfile_t *victim)
{
if (victim->needs_close && victim->file) {
fclose(victim->file);
} else if (victim->is_syslog) {
#ifdef HAVE_SYSLOG_H
if (--syslog_count == 0) {
/* There are no other syslogs; close the logging facility. */
closelog();
}
#endif
}
}
/** Add a log handler to send all messages of severity <b>loglevel</b>
* or higher to <b>stream</b>. */
void
add_stream_log(int loglevelMin, int loglevelMax,
const char *name, FILE *stream)
{
logfile_t *lf;
lf = tor_malloc_zero(sizeof(logfile_t));
lf->filename = tor_strdup(name);
lf->min_loglevel = loglevelMin;
lf->max_loglevel = loglevelMax;
lf->file = stream;
lf->next = logfiles;
logfiles = lf;
}
/** Add a log handler to receive messages during startup (before the real
* logs are initialized).
*/
void
add_temp_log(void)
{
add_stream_log(LOG_NOTICE, LOG_ERR, "<temp>", stdout);
logfiles->is_temporary = 1;
}
/**
* Add a log handler to send messages of severity between
* <b>logLevelmin</b> and <b>logLevelMax</b> to the function
* <b>cb</b>.
*/
int
add_callback_log(int loglevelMin, int loglevelMax, log_callback cb)
{
logfile_t *lf;
lf = tor_malloc_zero(sizeof(logfile_t));
lf->min_loglevel = loglevelMin;
lf->max_loglevel = loglevelMax;
lf->filename = tor_strdup("<callback>");
lf->callback = cb;
lf->next = logfiles;
logfiles = lf;
return 0;
}
void
change_callback_log_severity(int loglevelMin, int loglevelMax,
log_callback cb)
{
logfile_t *lf;
for (lf = logfiles; lf; lf = lf->next) {
if (lf->callback == cb) {
lf->min_loglevel = loglevelMin;
lf->max_loglevel = loglevelMax;
}
}
}
/** Close any log handlers added by add_temp_log or marked by mark_logs_temp */
void
close_temp_logs(void)
{
logfile_t *lf, **p;
for (p = &logfiles; *p; ) {
if ((*p)->is_temporary) {
lf = *p;
/* we use *p here to handle the edge case of the head of the list */
*p = (*p)->next;
close_log(lf);
tor_free(lf->filename);
tor_free(lf);
} else {
p = &((*p)->next);
}
}
}
/** Make all currently temporary logs (set to be closed by close_temp_logs)
* live again, and close all non-temporary logs. */
void
rollback_log_changes(void)
{
logfile_t *lf;
for (lf = logfiles; lf; lf = lf->next)
lf->is_temporary = ! lf->is_temporary;
close_temp_logs();
}
/** Configure all log handles to be closed by close_temp_logs */
void
mark_logs_temp(void)
{
logfile_t *lf;
for (lf = logfiles; lf; lf = lf->next)
lf->is_temporary = 1;
}
/**
* Add a log handler to send messages to <b>filename</b>. If opening
* the logfile fails, -1 is returned and errno is set appropriately
* (by fopen).
*/
int
add_file_log(int loglevelMin, int loglevelMax, const char *filename)
{
FILE *f;
f = fopen(filename, "a");
if (!f) return -1;
add_stream_log(loglevelMin, loglevelMax, filename, f);
logfiles->needs_close = 1;
if (log_tor_version(logfiles, 0) < 0) {
delete_log(logfiles);
}
return 0;
}
#ifdef HAVE_SYSLOG_H
/**
* Add a log handler to send messages to they system log facility.
*/
int
add_syslog_log(int loglevelMin, int loglevelMax)
{
logfile_t *lf;
if (syslog_count++ == 0)
/* This is the first syslog. */
openlog("Tor", LOG_PID | LOG_NDELAY, LOGFACILITY);
lf = tor_malloc_zero(sizeof(logfile_t));
lf->min_loglevel = loglevelMin;
lf->filename = tor_strdup("<syslog>");
lf->max_loglevel = loglevelMax;
lf->is_syslog = 1;
lf->next = logfiles;
logfiles = lf;
return 0;
}
#endif
/** If <b>level</b> is a valid log severity, return the corresponding
* numeric value. Otherwise, return -1. */
int
parse_log_level(const char *level)
{
if (!strcasecmp(level, "err"))
return LOG_ERR;
if (!strcasecmp(level, "warn"))
return LOG_WARN;
if (!strcasecmp(level, "notice"))
return LOG_NOTICE;
if (!strcasecmp(level, "info"))
return LOG_INFO;
if (!strcasecmp(level, "debug"))
return LOG_DEBUG;
return -1;
}
/** Return the string equivalent of a given log level. */
const char *
log_level_to_string(int level)
{
return sev_to_string(level);
}
/** Return the least severe log level that any current log is interested in. */
int
get_min_log_level(void)
{
logfile_t *lf;
int min = LOG_ERR;
for (lf = logfiles; lf; lf = lf->next) {
if (lf->min_loglevel > min)
min = lf->min_loglevel;
}
return min;
}
/** Switch all logs to output at most verbose level. */
void
switch_logs_debug(void)
{
logfile_t *lf;
for (lf = logfiles; lf; lf=lf->next) {
lf->min_loglevel = LOG_DEBUG;
}
}
#ifdef HAVE_EVENT_SET_LOG_CALLBACK
static const char *suppress_msg = NULL;
static void
libevent_logging_callback(int severity, const char *msg)
{
char buf[1024];
size_t n;
if (suppress_msg && strstr(msg, suppress_msg))
return;
n = strlcpy(buf, msg, sizeof(buf));
if (n && n < sizeof(buf) && buf[n-1] == '\n') {
buf[n-1] = '\0';
}
switch (severity) {
case _EVENT_LOG_DEBUG:
log(LOG_DEBUG, LD_NET, "Message from libevent: %s", buf);
break;
case _EVENT_LOG_MSG:
log(LOG_INFO, LD_NET, "Message from libevent: %s", buf);
break;
case _EVENT_LOG_WARN:
log(LOG_WARN, LD_GENERAL, "Warning from libevent: %s", buf);
break;
case _EVENT_LOG_ERR:
log(LOG_ERR, LD_GENERAL, "Error from libevent: %s", buf);
break;
default:
log(LOG_WARN, LD_GENERAL, "Message [%d] from libevent: %s",
severity, buf);
break;
}
}
void
configure_libevent_logging(void)
{
event_set_log_callback(libevent_logging_callback);
}
void
suppress_libevent_log_msg(const char *msg)
{
suppress_msg = msg;
}
#else
void
configure_libevent_logging(void)
{
}
void
suppress_libevent_log_msg(const char *msg)
{
}
#endif
#if 0
static void
dump_log_info(logfile_t *lf)
{
const char *tp;
if (lf->filename) {
printf("=== log into \"%s\" (%s-%s) (%stemporary)\n", lf->filename,
sev_to_string(lf->min_loglevel),
sev_to_string(lf->max_loglevel),
lf->is_temporary?"":"not ");
} else if (lf->is_syslog) {
printf("=== syslog (%s-%s) (%stemporary)\n",
sev_to_string(lf->min_loglevel),
sev_to_string(lf->max_loglevel),
lf->is_temporary?"":"not ");
} else {
printf("=== log (%s-%s) (%stemporary)\n",
sev_to_string(lf->min_loglevel),
sev_to_string(lf->max_loglevel),
lf->is_temporary?"":"not ");
}
}
void
describe_logs(void)
{
logfile_t *lf;
printf("==== BEGIN LOGS ====\n");
for (lf = logfiles; lf; lf = lf->next)
dump_log_info(lf);
printf("==== END LOGS ====\n");
}
#endif
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