Files
libguestfs/lib/hivex.c
2017-07-14 14:35:37 +01:00

112 lines
2.8 KiB
C

/* libguestfs
* Copyright (C) 2010-2012 Red Hat Inc.
*
* 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 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 <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <iconv.h>
#include "guestfs.h"
#include "guestfs-internal.h"
#include "guestfs-internal-actions.h"
/* Read the data from 'valueh', assume it is UTF16LE and convert it to
* UTF8. This is copied from hivex_value_string which doesn't work in
* the appliance because it uses iconv_open which doesn't work because
* we delete all the i18n databases.
*/
static char *utf16_to_utf8 (/* const */ char *input, size_t len);
char *
guestfs_impl_hivex_value_utf8 (guestfs_h *g, int64_t valueh)
{
char *ret;
size_t buflen;
CLEANUP_FREE char *buf = guestfs_hivex_value_value (g, valueh, &buflen);
if (buf == NULL)
return NULL;
ret = utf16_to_utf8 (buf, buflen);
if (ret == NULL) {
perrorf (g, "hivex: conversion of registry value to UTF8 failed");
return NULL;
}
return ret;
}
static char *
utf16_to_utf8 (/* const */ char *input, size_t len)
{
iconv_t ic = iconv_open ("UTF-8", "UTF-16LE");
if (ic == (iconv_t) -1)
return NULL;
/* iconv(3) has an insane interface ... */
/* Mostly UTF-8 will be smaller, so this is a good initial guess. */
size_t outalloc = len;
again:;
size_t inlen = len;
size_t outlen = outalloc;
char *out = malloc (outlen + 1);
if (out == NULL) {
int err = errno;
iconv_close (ic);
errno = err;
return NULL;
}
char *inp = input;
char *outp = out;
const size_t r =
iconv (ic, (ICONV_CONST char **) &inp, &inlen, &outp, &outlen);
if (r == (size_t) -1) {
if (errno == E2BIG) {
const int err = errno;
const size_t prev = outalloc;
/* Try again with a larger output buffer. */
free (out);
outalloc *= 2;
if (outalloc < prev) {
iconv_close (ic);
errno = err;
return NULL;
}
goto again;
}
else {
/* Else some conversion failure, eg. EILSEQ, EINVAL. */
const int err = errno;
iconv_close (ic);
free (out);
errno = err;
return NULL;
}
}
*outp = '\0';
iconv_close (ic);
return out;
}