File hdcode.c of Package hcode
#ifndef lint
static char rcsid[] = "$Id: hdcode.c,v 1.6 1997/11/19 04:16:52 news Exp news $";
#endif
/*
* $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
* CLEAN_QP Copyright Notice
*
* Most of the following CLEAN_QP codes are stealed from a package called
* hmailer-beta2 written by Song Woo-Geel cookie@venus.etri.re.kr.
*
* I am not sure if I can distribute it or not.
* However, The following is the original copyright statement.
* ***************************************************************
* Copyright (C) 1995 Song Woo-Geel
* Written by cookie@venus.etri.re.kr on May. 12 '95.
* ***************************************************************
*
* Now, the person who stealed cookie's code and his Copyright is
* ***************************************************************
* Copyright (C) 1997 Sang-yong Suh <sysuh@kigam.re.kr>
*
* THIS CODE IS PROVIDED AS IS AND WITHOUT ANY WARRANTY.
* USE IT AT YOUR OWN RISK AND DON'T COMAPLAIN ME OR TO COOKIE.
*
* $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
*/
/*
* Revision history
*
* 1997/05/16 sysuh Check charset="iso-2022-kr" (note the quotes)
* 1997/06/14 sysuh Replace charset=iso-8859-1 to EUC-KR
* 1997/11/18 sysuh Decode embedded QP texts within multipart.
*/
/*
* hMailDecode : decode Korean "Q" or "B" encoded HANGUL news article
*
* SYNOPSIS
* 1. standalone usage: compile with -D_MAIN
* hdcode [file]
*
* 2. as subroutine:
*
* hMailDecode(char *NULL, char *NULL); # initialize
* while (fgets(ibuf, sizeof(ibuf), stdin))
* hMailDecode(char *ibuf, char *obuf); # pass one line at a time
*
* OPTIONS
*
* decode file and write to stdout.
* [file] If file arg is missing, read stdin.
*
* NOTE:
* Header encoding : RFC-1342 ( "Q" or "B" encoding )
* Content encoding : Quoted-printable or ISO-2022-KR or Base64.
*/
#ifndef CLEAN_QP
void
hMailDecode(ibuf, obuf)
char *ibuf;
char *obuf;
{ }
#else /* CLEAN_QP */
#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <ctype.h>
#include <assert.h>
/* RFC-1342 header encoding start/end sequence */
#define PREFIX "=?"
#define POSTFIX "?="
#define SUFFIXQP "?Q?"
#define SUFFIXB64 "?B?"
#define OLDPREFIX "=?B?EUC-KR?"
#define HEADER_CTE "Content-Transfer-Encoding: "
#define HEADER_CT "Content-Type: "
#define KOR_CHARSET "EUC-KR" /* KSC-5601 */
/* ISO-2022 encoding designator escape sequence */
#define INTRO_ISO "\033$)C"
#define SHIFTOUT '\016' /* ASCII SO */
#define SHIFTIN '\017' /* ASCII SI */
#define DEL '\177' /* ASCII DEL */
#define OFFSET ( unsigned char ) 0200 /* or ISO encoding offset */
#define LSIZ 4096
#define TRUE 1
#define FALSE 0
enum section_t { SEC_HEADER, SEC_BODY };
enum encode_t { ENC_UNKNOWN, ENC_NONE, ENC_QP, ENC_ISO, ENC_B64 };
/* recognize encoding name and convert to encode_t type */
static enum encode_t encodingInfo(arg)
char *arg ;
{
if (!arg) return(ENC_UNKNOWN);
while (isspace(*arg)) arg++;
if (strncasecmp(arg, "7bit", 4) == 0
|| strncasecmp(arg, "8bit", 4) == 0
|| strncasecmp(arg, "none", 4) == 0)
return(ENC_NONE);
else if (strncasecmp(arg, "quoted-printable", 16) == 0)
return(ENC_QP);
else if (strncasecmp(arg, "base64", 6) == 0)
return(ENC_B64);
else
return(ENC_UNKNOWN);
}
/* convert CR+LF in middle or tail to LF. Overwrite! */
static void uncanonize(iptr)
char *iptr ;
{
char *optr = iptr ; /* overwrite input buffer */
static char oldch = '\0' ;
while ( *iptr ) {
if (( oldch=='\r' && (*iptr=='\n'||*iptr=='\r' )) || *iptr != '\r' )
*optr++ = *iptr ;
oldch = *iptr++;
}
*optr = '\0' ;
}
/* Decode ISO-2022-kr coded line to KSC-5601 */
static void decodeISOLine (iptr, optr)
char *iptr, *optr ;
{
int shifted = 0 ; /* Each line begins in unshifted state */
assert( iptr != NULL && optr != NULL );
while( *iptr ) {
if ( *iptr == SHIFTOUT )
shifted = 1 ;
else if ( *iptr == SHIFTIN )
shifted = 0 ;
else if ( shifted && *iptr > ' ' && *iptr < DEL )
*optr++ = (char) ( (unsigned char) *iptr + OFFSET);
else
*optr++ = *iptr ;
iptr++ ;
}
*optr = '\0';
assert( !shifted ); /* missing shift-in code ?? */
}
/*
* decodeB64Str()
* Return value : actual decoded resulting string length.
* limit is max length to decode, actual input may be shorter.
* Input size may be not multiple of 3 or 4. returns right size.
*
* Adapted by from bq.c, Copyright (C) 1992 Ienup Sung.
* @(#)bq.c: base64 encode/decode modules by is@ev.trigem.co.kr 1992.7.22
*/
#define LS6B 00077L /* least significant 6 bits */
#define LS8B 00377L /* least significant 8 bits */
#define PAD '='
static char *b64_alphabet =
"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
/* Decode base64 encoded string */
static int decodeB64Str(ibuf, obuf, limit )
char ibuf[], obuf[];
int limit ;
{
register unsigned long bitbuf = 0 ;
char *iptr = ibuf, *optr = obuf, *offs ;
int valid = 0 , mod4 = 0 ;
assert( ibuf !=NULL && obuf != NULL && limit >= 0 ) ;
while ( limit > 0 ) {
bitbuf = (bitbuf << 6) & ~ LS6B;
if( (offs = strchr( b64_alphabet, *iptr )) != NULL ) {
bitbuf |= (unsigned long) (offs - b64_alphabet) ;
valid++ ;
}
else /* if *iptr is PAD or non b64 alphabet, ignore */
bitbuf &= ~LS6B;
iptr++ ;
if ( *iptr == '\0' || iptr - ibuf >= limit ) {
/* align to 4 * 6 bit shifted postion */
while ( ++mod4 % 4 != 0 ) bitbuf = (bitbuf << 6) & ~ LS6B;
limit = 0 ; /* exit root */
}
else
++mod4 ;
if ( mod4 % 4 == 0 ) {
if (valid >= 2 ) *optr++ = (char)((bitbuf >> 16 ) & LS8B);
if (valid >= 3 ) *optr++ = (char)((bitbuf >> 8 ) & LS8B);
if (valid == 4 ) *optr++ = (char)((bitbuf) & LS8B);
bitbuf = 0 ; valid = 0 ;
}
}
*optr = '\0';
return(optr - obuf);
}
/* RFC1341 BASE64 BODY section decoding */
static void decodeB64Line(ibuf, obuf)
char ibuf[], obuf[] ;
{
assert( ibuf != NULL && obuf != NULL );
decodeB64Str(ibuf, obuf, strlen(ibuf)-1) ; /* ignore '\n' */
}
/* Convert two hexadecimal digit char to integer */
/* ex) h2toi('4', 'E') == 0x4e == 'N' */
/* If any char is not hexadecimal digit, return -1 */
static int h2toi( ch1, ch2 )
char ch1, ch2 ;
{
unsigned d1, d2 ;
if ((ch1) >= '0' && (ch1) <= '9' ) d1 = ( ch1 - '0' );
else if ((ch1) >= 'A' && (ch1) <= 'F' ) d1 = ( 10 + ch1 - 'A' );
else if ((ch1) >= 'a' && (ch1) <= 'f' ) d1 = ( 10 + ch1 - 'a' );
else return(-1);
if ((ch2) >= '0' && (ch2) <= '9' ) d2 = ( ch2 - '0' );
else if ((ch2) >= 'A' && (ch2) <= 'F' ) d2 = ( 10 + ch2 - 'A' );
else if ((ch2) >= 'a' && (ch2) <= 'f' ) d2 = ( 10 + ch2 - 'a' );
else return(-1);
return ( (int) (((d1<<4) + d2 ) & LS8B)) ;
}
static void decodeQPStr(ibuf, obuf, limit)
char ibuf[], obuf[] ;
int limit ;
{
char *iptr = ibuf, *optr = obuf ;
int ctmp ;
assert( iptr != NULL && obuf != NULL && limit >= 0 );
while( *iptr && ( iptr - ibuf < limit ) ) {
if ( *iptr == '=' && ( ctmp = h2toi( iptr[1], iptr[2])) >= 0 ){
*optr++ = (char) ctmp ;
iptr += 3 ;
}
else if ( *iptr == '_' ) { /* translate */
*optr++ = ' ' ; iptr++ ;
}
else
*optr++ = *iptr++ ;
}
*optr = '\0' ;
}
/* do RFC1341 QP BODY section decoding */
static void decodeQPLine(iptr, obuf)
char *iptr, obuf[] ;
{
char *optr = obuf ;
int ctmp ; /* h2toi() returns -1 on non-hexa digit */
assert( iptr != NULL && obuf != NULL );
while( *iptr ) {
if ( *iptr == '=' && ( ctmp = h2toi( iptr[1], iptr[2])) >= 0 ){
*optr++ = (char) ctmp ;
iptr += 3 ;
}
else if ( *iptr == '=' && ( iptr[1] == '\n' ))
iptr += 2 ; /* skip soft line break */
else
*optr++ = *iptr++;
}
*optr = '\0' ;
}
/* Cut off trailing blanks or CR-LF to LF */
static void fixTrailer(ibuf)
char ibuf[] ;
{
char *end = ibuf + strlen(ibuf)-1 ; /* line break */
assert( ibuf != NULL ) ;
if ( *end == '\n' && end >= ibuf ) end-- ;
if ( *end == '\r' && end >= ibuf ) end-- ;
while (( *end == ' ' || *end == '\t' ) && end >= ibuf ) end-- ;
if ( *++end != '\n' )
strcpy( end, "\n") ;
}
/* similar to strncpy(), but "to" string is always terminated */
static void strncpyz(to, from, len)
char *to, *from ;
int len ;
{
assert( to != NULL && from != NULL && len >= 0 ) ;
while( len-- > 0 && *from )
*to++ = *from++;
*to = '\0';
}
/* Decode header section by RFC1342 MIME "Q" or "B" header encoding rule */
static enum encode_t decodeHeader(iptr, optr, HeadEncoding)
char *iptr, *optr ;
enum encode_t HeadEncoding;
{
char *preptr, *sufptr, *txtptr, *postptr ;
assert( iptr != NULL && optr != NULL );
while(*iptr ) {
if ( ( preptr = strstr( iptr, PREFIX )) == NULL
|| ( sufptr = strchr( preptr+strlen(PREFIX), '?' )) == NULL
/* misssing POSTFIX, do not decode */
|| ( postptr = strstr( sufptr+strlen(SUFFIXQP), POSTFIX ))==NULL ) {
strcpy(optr, iptr ) ;
return HeadEncoding;
}
txtptr = sufptr+strlen(SUFFIXQP) ;
/* (header) =?EUC-KR?Q?=89=AB=CD=EF?= */
/* (ptr's) ^pre ^sf^txt ^post */
strncpy( optr, iptr, preptr-iptr ) ;
optr += preptr - iptr ; /* watch out order */
iptr = preptr ;
if ( strncasecmp( sufptr, SUFFIXQP, strlen(SUFFIXQP) ) == 0 ) {
decodeQPStr( txtptr , optr, postptr-txtptr ) ;
HeadEncoding = ENC_QP ;
}
else if ( strncasecmp( sufptr, SUFFIXB64, strlen(SUFFIXB64) ) == 0 ) {
decodeB64Str( txtptr , optr, postptr-txtptr ) ;
HeadEncoding = ENC_B64 ;
}
/* For compatibility with old (before Dec. 94) elm2.3h or hcode2.0 */
else if ( strncasecmp( preptr, OLDPREFIX, strlen(OLDPREFIX)) == 0 ) {
txtptr = preptr+strlen(OLDPREFIX) ;
decodeB64Str( txtptr , optr, postptr-txtptr ) ;
HeadEncoding = ENC_B64 ;
}
else { /* Unknown coding, do not decode */
strncpyz( optr, iptr, postptr+ strlen(POSTFIX)-iptr );
}
optr += strlen(optr) ;
iptr = postptr + strlen(POSTFIX) ;
*optr = '\0';
}
return HeadEncoding;
}
static int replace_charset(ibuf)
char *ibuf;
{
char *p, *q;
if ((p = strstr(ibuf, "charset="))) { /* replace with "euc-kr" */
q = p + 8;
if (*q == '"')
q++;
if (strncasecmp(q, "iso-2022-kr", 11) == 0 ||
strncasecmp(q, "iso-8859-1", 10) == 0)
strcpy(p+8, "EUC-KR\n");
return 1; /* charset detected */
}
return 0;
}
static char *strcasestr(buf, str)
char *buf;
char *str;
{
int i, n;
int lenstr = strlen(str);
n = strlen(buf) - lenstr + 1;
for (i=0; i<n; i++,buf++)
if (strncasecmp(buf, str, lenstr) == 0)
return buf;
return NULL;
}
static char *get_mpb_string(ibuf)
char *ibuf;
{
char *p, *bstr=NULL;
int len;
if ((p = strcasestr(ibuf, "boundary=\""))) { /* mpString */
p += 10;
len = strlen(p);
if (len > 10) { /* minimum length of the boundary string */
bstr = strdup(p);
p = bstr + len;
while (*--p == '\n' || *p == '"' || *p == ';')
*p = '\0';
}
}
return bstr;
}
static int isContentTypeText(cstr)
char *cstr;
{
return (strcasestr(cstr, "text") != NULL);
}
static int isUueHeader(str)
char *str;
{
int i, n;
while (isspace(*str))
str++;
if (strncasecmp(str, "begin ", 6) != 0)
return 0;
/* check three digits and a <blank>. */
str += 6;
n = strlen(str);
if (n < 5) /* 3 digits, 1 blank, and 1 filename */
return 0;
for (i=0; i<3; i++)
if (!isdigit(*str++))
return 0;
while (isspace(*str)) /* skip blanks */
str++;
if (*str)
return 1;
return 0;
}
static enum section_t
hMailDecode(ibuf, obuf)
char *ibuf;
char *obuf;
{
char *p, *q;
static enum section_t section = SEC_HEADER ;
static enum encode_t HeadEncoding = ENC_UNKNOWN;
static enum encode_t Encoding = ENC_UNKNOWN;
static int isoMode = 0 ;
static int isPendingCT = 0; /* previous CT header is incomplete */
static char *mpBoundary = NULL; /* multipart boundary text holder */
/* initialize */
if (!ibuf || !*ibuf) {
section = SEC_HEADER;
HeadEncoding = ENC_UNKNOWN;
Encoding = ENC_UNKNOWN;
isoMode = 0;
isPendingCT = 0;
if (mpBoundary)
free(mpBoundary);
mpBoundary = NULL;
return section;
}
fixTrailer(ibuf);
if (section == SEC_HEADER && *ibuf == '\n') {
section = SEC_BODY;
strcpy(obuf, "\n");
return section;
}
if (section == SEC_HEADER) {
if (isPendingCT) {
if (!isspace(*ibuf))
isPendingCT = 0;
else if (!replace_charset(ibuf) && !mpBoundary
&& (mpBoundary = get_mpb_string(ibuf))) {
strcpy(obuf, ibuf);
uncanonize(obuf);
return section;
}
}
/* Content-Type must be checked before Content-Transfer-Encoding */
if (strncasecmp(ibuf, HEADER_CT, strlen(HEADER_CT)) == 0) {
p = ibuf + strlen(HEADER_CT);
if ((q = strcasestr(p, "multipart"))) {
if ((mpBoundary = get_mpb_string(q+9)) == 0)
isPendingCT = 1; /* continued header */
} else if (!isContentTypeText(p)) {
Encoding = ENC_NONE;
} else if (!replace_charset(p))
isPendingCT = 1;
strcpy(obuf, ibuf);
/* Encoding = ENC_ISO and iso-8859-1 */
}
else if (Encoding != ENC_NONE &&
strncasecmp(ibuf, HEADER_CTE, strlen(HEADER_CTE)) == 0) {
Encoding = encodingInfo(ibuf+strlen(HEADER_CTE)) ;
if (Encoding == ENC_QP || Encoding == ENC_B64)
sprintf(obuf, "%s%s\n", HEADER_CTE, "8bit") ;
else
strcpy(obuf, ibuf);
}
else if (strstr(ibuf, PREFIX))
HeadEncoding = decodeHeader(ibuf, obuf, HeadEncoding);
else
strcpy(obuf, ibuf);
}
else if (section == SEC_BODY) {
if (mpBoundary && strstr(ibuf, mpBoundary)) {
section = SEC_HEADER;
HeadEncoding = ENC_UNKNOWN;
Encoding = ENC_UNKNOWN;
isoMode = 0;
strcpy(obuf, ibuf);
}
else if (Encoding == ENC_NONE)
strcpy(obuf, ibuf);
else if (isUueHeader(ibuf)) {
Encoding = ENC_NONE;
strcpy(obuf, ibuf);
}
else if (Encoding == ENC_QP)
decodeQPLine(ibuf, obuf);
else if (Encoding == ENC_B64)
decodeB64Line(ibuf, obuf) ;
else if ((p = strstr(ibuf, INTRO_ISO))) {
/* remove ISO intro sequnce from ibuf */
strcpy( p, p + strlen(INTRO_ISO));
decodeISOLine(ibuf, obuf);
isoMode = 1 ;
}
/*
* If headers are "B" encoded AND content line has SO char without prioior
* ISO introducer, we assume missing introducer. It's feature.
*/
else if ((isoMode || HeadEncoding == ENC_B64)
&& strchr(ibuf, SHIFTOUT) != NULL )
decodeISOLine(ibuf, obuf );
else
strcpy(obuf, ibuf);
}
uncanonize(obuf);
return section;
}
/*
** Is it posted on a Han newsgroups?
*/
int
IsHanNewsgroups(char *line)
{
char *p;
for (p=line; p; p++) {
while (isspace(*p))
p++;
if (strncmp(p, "han.", 4) == 0 &&
strncmp(p, "han.test", 8) != 0)
return TRUE;
p = strchr(p, ',');
if (p == NULL)
break;
}
return FALSE;
}
/*
** Retrun CleanQP filtered article. NULL indicates ERROR.
*/
char *
hNewsCleanQP(char *article, int checkNewsgroups)
{
char *newart;
size_t newlen;
int used;
char *p, *q, *next;
char hold;
char *orig = NULL;
enum section_t section;
newlen = strlen(article) + LSIZ;
newart = malloc(newlen);
if (newart == NULL) {
fprintf(stderr, "hNewsDecode: can't malloc %d bytes\n", newlen);
return NULL;
}
section = hMailDecode((char *)NULL, (char *)NULL);
next = article;
used = 0;
for (p=next; next; p=next, *p=hold) {
/*
** Make the input line. Remember the char of start of next line.
*/
next = strchr(p, '\n');
if (next) {
hold = *++next;
*next = '\0';
}
/*
** Check Newsgroups line.
*/
if (checkNewsgroups && strncasecmp(p, "newsgroups:", 11) == 0) {
checkNewsgroups = FALSE;
if (!IsHanNewsgroups(p+11)) {
free(newart);
if (next)
*next = hold;
return NULL;
}
}
/*
** Allocate output space
*/
if (newlen - used < LSIZ + LSIZ) {
newlen += LSIZ + LSIZ;
newart = realloc(newart, newlen);
if (newart == NULL) {
fprintf(stderr, "hNewsDecode: can't realloc %d bytes\n",
newlen);
if (next)
*next = hold; /* recover old char */
return NULL;
}
}
/*
** Apply filter, and set up next output pointer.
*/
q = newart + used;
strcpy(q, p);
section = hMailDecode(q, q);
if (section == SEC_HEADER) {
if (orig == NULL && !isspace(*p) && strcmp(p, q))
orig = p;
if (orig && (!isspace(hold) || hold == '\n')) {
used += strlen(q);
sprintf(newart+used, "X-Orig-%s", orig);
orig = NULL;
}
}
used += strlen(newart+used);
if (next == NULL)
break;
}
return newart;
}
#ifdef _MAIN
int main(argc, argv)
int argc;
char **argv;
{
char *article, *newart;
char line[LSIZ];
int len;
int used = 0;
size_t artlen = 0;
int checkNewsgroups = FALSE;
int i;
char *infile = NULL;
for (i=1; i<argc; i++)
if (strcmp(argv[i], "-n") == 0)
checkNewsgroups = TRUE;
else if (*argv[i] != '-' && infile == NULL)
infile = argv[i];
else {
fprintf(stderr, "usage: %s [-n] [file]\n", argv[0]);
exit(1);
}
if (infile && !freopen(infile, "r", stdin)) {
fprintf(stderr, "can't open input %s\n", infile);
exit(1);
}
artlen = 100 * LSIZ;
article = malloc(artlen);
if (article == NULL) {
fprintf(stderr, "can't malloc %d bytes\n", artlen);
exit(1);
}
while (fgets(line, sizeof(line), stdin)) {
len = strlen(line);
if (artlen <= used + len) {
artlen += LSIZ * 10;
article = realloc(article, artlen);
if (article == NULL) {
fprintf(stderr, "can't realloc %d bytes\n", artlen);
exit(1);
}
}
strncpy(article+used, line, len);
used += len;
}
*(article + used) = '\0';
newart = hNewsCleanQP(article, checkNewsgroups);
if (newart) {
free(article);
article = newart;
}
while (*article) {
putchar(*article++);
}
return 0;
}
#endif /* _MAIN */
#endif /* CLEAN_QP */
