Working on #830. Cope with bad conversions better - don't just memcpy but

try a crap conversion instead. Next this needs to be done to the convert_alloc
function.
Actually fixes some valgrind warnings as well - cool !
Jeremy.
(This used to be commit 6a7919f254)

source3/lib/charcnv.c

@@ -184,14 +184,18 @@ static size_t convert_string_internal(charset_t from, charset_t to,
 		}
 	}
 
+
 	if (descriptor == (smb_iconv_t)-1 || descriptor == (smb_iconv_t)0) {
 		if (!conv_silent)
 			DEBUG(0,("convert_string_internal: Conversion not supported.\n"));
-		goto use_as_is;
+		return 0;
 	}
 
 	i_len=srclen;
 	o_len=destlen;
+
+ again:
+
 	retval = smb_iconv(descriptor, (char **)&inbuf, &i_len, &outbuf, &o_len);
 	if(retval==(size_t)-1) {
 	    	const char *reason="unknown error";
@@ -227,12 +231,76 @@ static size_t convert_string_internal(charset_t from, charset_t to,
 
  use_as_is:
 
-	/* conversion not supported, use as is */
+	/* 
+	 * Conversion not supported. This is actually an error, but there are so
+	 * many misconfigured iconv systems and smb.conf's out there we can't just
+	 * fail. Do a very bad conversion instead.... JRA.
+	 */
+
 	{
-		size_t len = MIN(srclen,destlen);
-		if (len)
-			memcpy(dest,src,len);
-		return len;
+		if (o_len == 0 || i_len == 0)
+			return destlen - o_len;
+
+		if (from == CH_UCS2 && to != CH_UCS2) {
+			/* Can't convert from ucs2 to multibyte. Just truncate this char to ascii. */
+			if (i_len < 2)
+				return destlen - o_len;
+			if (i_len >= 2) {
+				*outbuf = inbuf[0];
+
+				outbuf++;
+				o_len--;
+
+				inbuf += 2;
+				i_len -= 2;
+			}
+
+			if (o_len == 0 || i_len == 0)
+				return destlen - o_len;
+
+			/* Keep trying with the next char... */
+			goto again;
+
+		} else if (from != CH_UCS2 && to == CH_UCS2) {
+			/* Can't convert to ucs2 - just widen by adding zero. */
+			if (o_len < 2)
+				return destlen;
+			outbuf[0] = inbuf[0];
+			outbuf[1] = '\0';
+
+			inbuf++;
+			i_len--;
+
+			outbuf += 2;
+			o_len -= 2;
+
+			if (o_len == 0 || i_len == 0)
+				return destlen - o_len;
+
+			/* Keep trying with the next char... */
+			goto again;
+
+		} else if (from != CH_UCS2 && to != CH_UCS2) {
+			/* Failed multibyte to multibyte. Just copy 1 char and
+				try again. */
+			outbuf[0] = inbuf[0];
+
+			inbuf++;
+			i_len--;
+
+			outbuf++;
+			o_len--;
+
+			if (o_len == 0 || i_len == 0)
+				return destlen - o_len;
+
+			/* Keep trying with the next char... */
+			goto again;
+
+		} else {
+			/* Keep compiler happy.... */
+			return destlen - o_len;
+		}
 	}
 }
 
@@ -241,9 +309,9 @@ static size_t convert_string_internal(charset_t from, charset_t to,
  * Fast path version - handles ASCII first.
  *
  * @param src pointer to source string (multibyte or singlebyte)
- * @param srclen length of the source string in bytes
+ * @param srclen length of the source string in bytes, or -1 for nul terminated.
  * @param dest pointer to destination string (multibyte or singlebyte)
- * @param destlen maximal length allowed for string
+ * @param destlen maximal length allowed for string - *NEVER* -1.
  * @returns the number of bytes occupied in the destination
  *
  * Ensure the srclen contains the terminating zero.
@@ -257,11 +325,15 @@ size_t convert_string(charset_t from, charset_t to,
 		      void *dest, size_t destlen)
 {
 	/*
-	 * NB. We deliberately don't do a strlen here is srclen == -1.
+	 * NB. We deliberately don't do a strlen here if srclen == -1.
 	 * This is very expensive over millions of calls and is taken
 	 * care of in the slow path in convert_string_internal. JRA.
 	 */
 
+#ifdef DEVELOPER
+	SMB_ASSERT(destlen != (size_t)-1);
+#endif
+
 	if (srclen == 0)
 		return 0;
 
@@ -302,7 +374,7 @@ size_t convert_string(charset_t from, charset_t to,
 		unsigned char lastp;
 
 		/* If all characters are ascii, fast path here. */
-		while ((slen >= 2) && dlen) {
+		while (((slen == (size_t)-1) || (slen >= 2)) && dlen) {
 			if (((lastp = *p) <= 0x7f) && (p[1] == 0)) {
 				*q++ = *p;
 				if (slen != (size_t)-1) {

source3/lib/iconv.c

@@ -589,4 +589,3 @@ toobig:
 	errno = E2BIG;
 	return -1;
 }
-