Diff of /trunk/mkinitrd-magellan/busybox/networking/udhcp/domain_codec.c

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	revision 983 by niro, Fri Apr 24 18:33:46 2009 UTC	revision 984 by niro, Sun May 30 11:32:42 2010 UTC
#	Line 25	Line 25
25	*/	*/
26	char* FAST_FUNC dname_dec(const uint8_t *cstr, int clen, const char *pre)	char* FAST_FUNC dname_dec(const uint8_t *cstr, int clen, const char *pre)
27	{	{
28	const uint8_t *c;	char *ret = ret; /* for compiler */
	int crtpos, retpos, depth, plen = 0, len = 0;
29	char *dst = NULL;	char *dst = NULL;
30
	if (!cstr)
	return NULL;
	if (pre)
	plen = strlen(pre);
31	/* We make two passes over the cstr string. First, we compute	/* We make two passes over the cstr string. First, we compute
32	* how long the resulting string would be. Then we allocate a	* how long the resulting string would be. Then we allocate a
33	* new buffer of the required length, and fill it in with the	* new buffer of the required length, and fill it in with the
#	Line 42  char* FAST_FUNC dname_dec(const uint8_t	Line 35  char* FAST_FUNC dname_dec(const uint8_t
35	* having to deal with requiring callers to supply their own	* having to deal with requiring callers to supply their own
36	* buffer, then having to check if it's sufficiently large, etc.	* buffer, then having to check if it's sufficiently large, etc.
37	*/	*/
38		while (1) {
39	while (!dst) {	/* note: "return NULL" below are leak-safe since
40		* dst isn't yet allocated */
41	if (len > 0) { /* second pass? allocate dst buffer and copy pre */	const uint8_t *c;
42	dst = xmalloc(len + plen);	unsigned crtpos, retpos, depth, len;
	memcpy(dst, pre, plen);
	}
43
44	crtpos = retpos = depth = len = 0;	crtpos = retpos = depth = len = 0;
45	while (crtpos < clen) {	while (crtpos < clen) {
46	c = cstr + crtpos;	c = cstr + crtpos;
47
48	if ((*c & NS_CMPRSFLGS) != 0) { /* pointer */	if (*c & NS_CMPRSFLGS) {
49	if (crtpos + 2 > clen) /* no offset to jump to? abort */	/* pointer */
50		if (crtpos + 2 > clen) /* no offset to jump to? abort */
51	return NULL;	return NULL;
52	if (retpos == 0) /* toplevel? save return spot */	if (retpos == 0) /* toplevel? save return spot */
53	retpos = crtpos + 2;	retpos = crtpos + 2;
54	depth++;	depth++;
55	crtpos = ((*c & 0x3f) << 8) | (*(c + 1) & 0xff); /* jump */	crtpos = ((c[0] & 0x3f) << 8) | (c[1] & 0xff); /* jump */
56	} else if (*c) { /* label */	} else if (*c) {
57	if (crtpos + *c + 1 > clen) /* label too long? abort */	/* label */
58		if (crtpos + *c + 1 > clen) /* label too long? abort */
59	return NULL;	return NULL;
60	if (dst)	if (dst)
61	memcpy(dst + plen + len, c + 1, *c);	memcpy(dst + len, c + 1, *c);
62	len += *c + 1;	len += *c + 1;
63	crtpos += *c + 1;	crtpos += *c + 1;
64	if (dst)	if (dst)
65	*(dst + plen + len - 1) = '.';	dst[len - 1] = '.';
66	} else { /* null: end of current domain name */	} else {
67	if (retpos == 0) { /* toplevel? keep going */	/* null: end of current domain name */
68		if (retpos == 0) {
69		/* toplevel? keep going */
70	crtpos++;	crtpos++;
71	} else { /* return to toplevel saved spot */	} else {
72		/* return to toplevel saved spot */
73	crtpos = retpos;	crtpos = retpos;
74	retpos = depth = 0;	retpos = depth = 0;
75	}	}
76	if (dst)	if (dst)
77	*(dst + plen + len - 1) = ' ';	dst[len - 1] = ' ';
78	}	}
79
80	if (depth > NS_MAXDNSRCH || /* too many jumps? abort, it's a loop */	if (depth > NS_MAXDNSRCH /* too many jumps? abort, it's a loop */
81	len > NS_MAXDNAME * NS_MAXDNSRCH) /* result too long? abort */	|| len > NS_MAXDNAME * NS_MAXDNSRCH /* result too long? abort */
82		) {
83	return NULL;	return NULL;
84		}
85	}	}
86
87	if (!len) /* expanded string has 0 length? abort */	if (!len) /* expanded string has 0 length? abort */
88	return NULL;	return NULL;
89
90	if (dst)	if (!dst) { /* first pass? */
91	*(dst + plen + len - 1) = '\0';	/* allocate dst buffer and copy pre */
92		unsigned plen = strlen(pre);
93		ret = dst = xmalloc(plen + len);
94		memcpy(dst, pre, plen);
95		dst += plen;
96		} else {
97		dst[len - 1] = '\0';
98		break;
99		}
100	}	}
101
102	return dst;	return ret;
103	}	}
104
105	/* Convert a domain name (src) from human-readable "foo.blah.com" format into	/* Convert a domain name (src) from human-readable "foo.blah.com" format into

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