/* assuan-logging.c - Default logging function.
* Copyright (C) 2002, 2003, 2004, 2007, 2009,
* 2010 Free Software Foundation, Inc.
*
* This file is part of Assuan.
*
* Assuan 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.
*
* Assuan 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 program; if not, see <http://www.gnu.org/licenses/>.
* SPDX-License-Identifier: LGPL-2.1+
*/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdarg.h>
#ifdef HAVE_W32_SYSTEM
# ifdef HAVE_WINSOCK2_H
# include <winsock2.h>
# endif
# include <windows.h>
#endif /*HAVE_W32_SYSTEM*/
#include <errno.h>
#include <ctype.h>
#include "assuan-defs.h"
/* The default log handler is useful for global logging, but it should
only be used by one user of libassuan at a time. Libraries that
use libassuan can register their own log handler. */
/* A common prefix for all log messages. */
static char prefix_buffer[80];
/* A global flag read from the environment to check if to enable full
logging of buffer data. This is also used by custom log
handlers. */
static int full_logging;
/* A bitfield that specifies the categories to log. */
static int log_cats;
#define TEST_LOG_CAT(x) (!! (log_cats & (1 << (x - 1))))
static FILE *_assuan_log;
void
_assuan_init_log_envvars (void)
{
char *flagstr;
full_logging = !!getenv ("ASSUAN_FULL_LOGGING");
flagstr = getenv ("ASSUAN_DEBUG");
if (flagstr)
log_cats = atoi (flagstr);
else /* Default to log the control channel. */
log_cats = (1 << (ASSUAN_LOG_CONTROL - 1));
_assuan_sysutils_blurb (); /* Make sure this code gets linked in. */
}
void
assuan_set_assuan_log_stream (FILE *fp)
{
_assuan_log = fp;
_assuan_init_log_envvars ();
}
/* Set the per context log stream. Also enable the default log stream
if it has not been set. */
void
assuan_set_log_stream (assuan_context_t ctx, FILE *fp)
{
if (ctx)
{
if (ctx->log_fp)
fflush (ctx->log_fp);
ctx->log_fp = fp;
if (! _assuan_log)
assuan_set_assuan_log_stream (fp);
}
}
/* Set the prefix to be used for logging to TEXT or resets it to the
default if TEXT is NULL. */
void
assuan_set_assuan_log_prefix (const char *text)
{
if (text)
{
strncpy (prefix_buffer, text, sizeof (prefix_buffer)-1);
prefix_buffer[sizeof (prefix_buffer)-1] = 0;
}
else
*prefix_buffer = 0;
}
/* Get the prefix to be used for logging. */
const char *
assuan_get_assuan_log_prefix (void)
{
return prefix_buffer;
}
/* Default log handler. */
int
_assuan_log_handler (assuan_context_t ctx, void *hook, unsigned int cat,
const char *msg)
{
FILE *fp;
const char *prf;
int saved_errno = errno;
/* For now. */
if (msg == NULL)
return TEST_LOG_CAT (cat);
if (! TEST_LOG_CAT (cat))
return 0;
fp = ctx->log_fp ? ctx->log_fp : _assuan_log;
if (!fp)
return 0;
prf = assuan_get_assuan_log_prefix ();
if (*prf)
fprintf (fp, "%s[%u]: ", prf, (unsigned int)getpid ());
fprintf (fp, "%s", msg);
/* If the log stream is a file, the output would be buffered. This
is bad for debugging, thus we flush the stream if FORMAT ends
with a LF. */
if (msg && *msg && msg[strlen (msg) - 1] == '\n')
fflush (fp);
gpg_err_set_errno (saved_errno);
return 0;
}
/* Log a control channel message. This is either a STRING with a
diagnostic or actual data in (BUFFER1,LENGTH1) and
(BUFFER2,LENGTH2). If OUTBOUND is true the data is intended for
the peer. */
void
_assuan_log_control_channel (assuan_context_t ctx, int outbound,
const char *string,
const void *buffer1, size_t length1,
const void *buffer2, size_t length2)
{
int res;
char *outbuf;
int saved_errno;
/* Check whether logging is enabled and do a quick check to see
whether the callback supports our category. */
if (!ctx
|| !ctx->log_cb
|| ctx->flags.no_logging
|| !(*ctx->log_cb) (ctx, ctx->log_cb_data, ASSUAN_LOG_CONTROL, NULL))
return;
saved_errno = errno;
/* Note that we use the inbound channel fd as the printed channel
number for both directions. */
#ifdef HAVE_W32_SYSTEM
# define CHANNEL_FMT "%p"
#else
# define CHANNEL_FMT "%d"
#endif
#define TOHEX(val) (((val) < 10) ? ((val) + '0') : ((val) - 10 + 'a'))
if (!buffer1 && buffer2)
{
buffer1 = buffer2;
length1 = length2;
buffer2 = NULL;
length2 = 0;
}
if (ctx->flags.confidential && !string && buffer1)
string = "[Confidential data not shown]";
if (string)
{
/* Print the diagnostic. */
res = gpgrt_asprintf (&outbuf, "chan_" CHANNEL_FMT " %s [%s]\n",
ctx->inbound.fd, outbound? "->":"<-", string);
}
else if (buffer1)
{
/* Print the control channel data. */
const unsigned char *s;
unsigned int n, x;
for (n = length1, s = buffer1; n; n--, s++)
if ((!isascii (*s) || iscntrl (*s) || !isprint (*s) || !*s)
&& !(*s >= 0x80))
break;
if (!n && buffer2)
{
for (n = length2, s = buffer2; n; n--, s++)
if ((!isascii (*s) || iscntrl (*s) || !isprint (*s) || !*s)
&& !(*s >= 0x80))
break;
}
if (!buffer2)
length2 = 0;
if (!n && (length1 && *(const char*)buffer1 != '['))
{
/* No control characters and not starting with our error
message indicator. Log it verbatim. */
res = gpgrt_asprintf (&outbuf, "chan_" CHANNEL_FMT " %s %.*s%.*s\n",
ctx->inbound.fd, outbound? "->":"<-",
(int)length1, (const char*)buffer1,
(int)length2, buffer2? (const char*)buffer2:"");
}
else
{
/* The buffer contains control characters - do a hex dump.
Even in full logging mode we limit the line length -
however this is no real limit because the provided
buffers will never be larger than the maximum assuan line
length. */
char *hp;
unsigned int nbytes;
unsigned int maxbytes = full_logging? (2*LINELENGTH) : 16;
nbytes = length1 + length2;
if (nbytes > maxbytes)
nbytes = maxbytes;
if (!(outbuf = malloc (50 + 3*nbytes + 60 + 3 + 1)))
res = -1;
else
{
res = 0;
hp = outbuf;
snprintf (hp, 50, "chan_" CHANNEL_FMT " %s [",
ctx->inbound.fd, outbound? "->":"<-");
hp += strlen (hp);
n = 0;
for (s = buffer1, x = 0; x < length1 && n < nbytes; x++, n++)
{
*hp++ = ' ';
*hp++ = TOHEX (*s >> 4);
*hp++ = TOHEX (*s & 0x0f);
s++;
}
for (s = buffer2, x = 0; x < length2 && n < nbytes; x++, n++)
{
*hp++ = ' ';
*hp++ = TOHEX (*s >> 4);
*hp++ = TOHEX (*s & 0x0f);
s++;
}
if (nbytes < length1 + length2)
{
snprintf (hp, 60, " ...(%u byte(s) skipped)",
(unsigned int)((length1+length2) - nbytes));
hp += strlen (hp);
}
strcpy (hp, " ]\n");
}
}
}
else
{
res = 0;
outbuf = NULL;
}
if (res < 0)
ctx->log_cb (ctx, ctx->log_cb_data, ASSUAN_LOG_CONTROL,
"[libassuan failed to format the log message]");
else if (outbuf)
{
ctx->log_cb (ctx, ctx->log_cb_data, ASSUAN_LOG_CONTROL, outbuf);
gpgrt_free (outbuf);
}
#undef TOHEX
#undef CHANNEL_FMT
gpg_err_set_errno (saved_errno);
}