Support varlena fields with single-byte headers and unaligned storage.

This commit breaks any code that assumes that the mere act of forming a tuple
(without writing it to disk) does not "toast" any fields.  While all available
regression tests pass, I'm not totally sure that we've fixed every nook and
cranny, especially in contrib.

Greg Stark with some help from Tom Lane

1 files changed, 50 insertions, 54 deletions

diff --git a/src/backend/utils/adt/network.c b/src/backend/utils/adt/network.c
index 88fa427450f..c1dadfbcc1b 100644
--- a/src/backend/utils/adt/network.c
+++ b/src/backend/utils/adt/network.c
@@ -1,7 +1,7 @@
 /*
  *	PostgreSQL type definitions for the INET and CIDR types.
  *
- *	$PostgreSQL: pgsql/src/backend/utils/adt/network.c,v 1.68 2007/02/27 23:48:08 tgl Exp $
+ *	$PostgreSQL: pgsql/src/backend/utils/adt/network.c,v 1.69 2007/04/06 04:21:43 tgl Exp $
  *
  *	Jon Postel RIP 16 Oct 1998
  */
@@ -30,23 +30,38 @@ static int	ip_addrsize(inet *inetptr);
 static inet *internal_inetpl(inet *ip, int64 addend);
 
 /*
- *	Access macros.
+ *	Access macros.  We use VARDATA_ANY so that we can process short-header
+ *	varlena values without detoasting them.  This requires a trick:
+ *	VARDATA_ANY assumes the varlena header is already filled in, which is
+ *	not the case when constructing a new value (until SET_INET_VARSIZE is
+ *	called, which we typically can't do till the end).  Therefore, we
+ *	always initialize the newly-allocated value to zeroes (using palloc0).
+ *	A zero length word will look like the not-1-byte case to VARDATA_ANY,
+ *	and so we correctly construct an uncompressed value.
+ *
+ *	Note that ip_maxbits() and SET_INET_VARSIZE() require
+ *	the family field to be set correctly.
  */
 
 #define ip_family(inetptr) \
-	(((inet_struct *)VARDATA(inetptr))->family)
+	(((inet_struct *) VARDATA_ANY(inetptr))->family)
 
 #define ip_bits(inetptr) \
-	(((inet_struct *)VARDATA(inetptr))->bits)
+	(((inet_struct *) VARDATA_ANY(inetptr))->bits)
 
 #define ip_addr(inetptr) \
-	(((inet_struct *)VARDATA(inetptr))->ipaddr)
+	(((inet_struct *) VARDATA_ANY(inetptr))->ipaddr)
 
 #define ip_maxbits(inetptr) \
 	(ip_family(inetptr) == PGSQL_AF_INET ? 32 : 128)
 
+#define SET_INET_VARSIZE(dst) \
+	SET_VARSIZE(dst, VARHDRSZ + offsetof(inet_struct, ipaddr) + \
+				ip_addrsize(dst))
+
+
 /*
- * Return the number of bytes of storage needed for this data type.
+ * Return the number of bytes of address storage needed for this data type.
  */
 static int
 ip_addrsize(inet *inetptr)
@@ -71,7 +86,7 @@ network_in(char *src, bool is_cidr)
 	int			bits;
 	inet	   *dst;
 
-	dst = (inet *) palloc0(VARHDRSZ + sizeof(inet_struct));
+	dst = (inet *) palloc0(sizeof(inet));
 
 	/*
 	 * First, check to see if this is an IPv6 or IPv4 address.	IPv6 addresses
@@ -105,10 +120,8 @@ network_in(char *src, bool is_cidr)
 					 errdetail("Value has bits set to right of mask.")));
 	}
 
-	SET_VARSIZE(dst, VARHDRSZ +
-		((char *) ip_addr(dst) - (char *) VARDATA(dst)) +
-		ip_addrsize(dst));
 	ip_bits(dst) = bits;
+	SET_INET_VARSIZE(dst);
 
 	return dst;
 }
@@ -194,7 +207,7 @@ network_recv(StringInfo buf, bool is_cidr)
 				i;
 
 	/* make sure any unused bits in a CIDR value are zeroed */
-	addr = (inet *) palloc0(VARHDRSZ + sizeof(inet_struct));
+	addr = (inet *) palloc0(sizeof(inet));
 
 	ip_family(addr) = pq_getmsgbyte(buf);
 	if (ip_family(addr) != PGSQL_AF_INET &&
@@ -220,9 +233,6 @@ network_recv(StringInfo buf, bool is_cidr)
 		/* translator: %s is inet or cidr */
 				 errmsg("invalid length in external \"%s\" value",
 						is_cidr ? "cidr" : "inet")));
-	SET_VARSIZE(addr, VARHDRSZ +
-		((char *) ip_addr(addr) - (char *) VARDATA(addr)) +
-		ip_addrsize(addr));
 
 	addrptr = (char *) ip_addr(addr);
 	for (i = 0; i < nb; i++)
@@ -240,6 +250,8 @@ network_recv(StringInfo buf, bool is_cidr)
 					 errdetail("Value has bits set to right of mask.")));
 	}
 
+	SET_INET_VARSIZE(addr);
+
 	return addr;
 }
 
@@ -348,8 +360,8 @@ inet_to_cidr(PG_FUNCTION_ARGS)
 		elog(ERROR, "invalid inet bit length: %d", bits);
 
 	/* clone the original data */
-	dst = (inet *) palloc(VARSIZE(src));
-	memcpy(dst, src, VARSIZE(src));
+	dst = (inet *) palloc(VARSIZE_ANY(src));
+	memcpy(dst, src, VARSIZE_ANY(src));
 
 	/* zero out any bits to the right of the netmask */
 	byte = bits / 8;
@@ -387,8 +399,8 @@ inet_set_masklen(PG_FUNCTION_ARGS)
 				 errmsg("invalid mask length: %d", bits)));
 
 	/* clone the original data */
-	dst = (inet *) palloc(VARSIZE(src));
-	memcpy(dst, src, VARSIZE(src));
+	dst = (inet *) palloc(VARSIZE_ANY(src));
+	memcpy(dst, src, VARSIZE_ANY(src));
 
 	ip_bits(dst) = bits;
 
@@ -414,8 +426,8 @@ cidr_set_masklen(PG_FUNCTION_ARGS)
 				 errmsg("invalid mask length: %d", bits)));
 
 	/* clone the original data */
-	dst = (inet *) palloc(VARSIZE(src));
-	memcpy(dst, src, VARSIZE(src));
+	dst = (inet *) palloc(VARSIZE_ANY(src));
+	memcpy(dst, src, VARSIZE_ANY(src));
 
 	ip_bits(dst) = bits;
 
@@ -546,7 +558,7 @@ hashinet(PG_FUNCTION_ARGS)
 	int			addrsize = ip_addrsize(addr);
 
 	/* XXX this assumes there are no pad bytes in the data structure */
-	return hash_any((unsigned char *) VARDATA(addr), addrsize + 2);
+	return hash_any((unsigned char *) VARDATA_ANY(addr), addrsize + 2);
 }
 
 /*
@@ -762,7 +774,7 @@ network_broadcast(PG_FUNCTION_ARGS)
 			   *b;
 
 	/* make sure any unused bits are zeroed */
-	dst = (inet *) palloc0(VARHDRSZ + sizeof(inet_struct));
+	dst = (inet *) palloc0(sizeof(inet));
 
 	if (ip_family(ip) == PGSQL_AF_INET)
 		maxbytes = 4;
@@ -793,9 +805,7 @@ network_broadcast(PG_FUNCTION_ARGS)
 
 	ip_family(dst) = ip_family(ip);
 	ip_bits(dst) = ip_bits(ip);
-	SET_VARSIZE(dst, VARHDRSZ +
-		((char *) ip_addr(dst) - (char *) VARDATA(dst)) +
-		ip_addrsize(dst));
+	SET_INET_VARSIZE(dst);
 
 	PG_RETURN_INET_P(dst);
 }
@@ -812,7 +822,7 @@ network_network(PG_FUNCTION_ARGS)
 			   *b;
 
 	/* make sure any unused bits are zeroed */
-	dst = (inet *) palloc0(VARHDRSZ + sizeof(inet_struct));
+	dst = (inet *) palloc0(sizeof(inet));
 
 	bits = ip_bits(ip);
 	a = ip_addr(ip);
@@ -838,9 +848,7 @@ network_network(PG_FUNCTION_ARGS)
 
 	ip_family(dst) = ip_family(ip);
 	ip_bits(dst) = ip_bits(ip);
-	SET_VARSIZE(dst, VARHDRSZ +
-		((char *) ip_addr(dst) - (char *) VARDATA(dst)) +
-		ip_addrsize(dst));
+	SET_INET_VARSIZE(dst);
 
 	PG_RETURN_INET_P(dst);
 }
@@ -856,7 +864,7 @@ network_netmask(PG_FUNCTION_ARGS)
 	unsigned char *b;
 
 	/* make sure any unused bits are zeroed */
-	dst = (inet *) palloc0(VARHDRSZ + sizeof(inet_struct));
+	dst = (inet *) palloc0(sizeof(inet));
 
 	bits = ip_bits(ip);
 	b = ip_addr(dst);
@@ -881,9 +889,7 @@ network_netmask(PG_FUNCTION_ARGS)
 
 	ip_family(dst) = ip_family(ip);
 	ip_bits(dst) = ip_maxbits(ip);
-	SET_VARSIZE(dst, VARHDRSZ +
-		((char *) ip_addr(dst) - (char *) VARDATA(dst)) +
-		ip_addrsize(dst));
+	SET_INET_VARSIZE(dst);
 
 	PG_RETURN_INET_P(dst);
 }
@@ -900,7 +906,7 @@ network_hostmask(PG_FUNCTION_ARGS)
 	unsigned char *b;
 
 	/* make sure any unused bits are zeroed */
-	dst = (inet *) palloc0(VARHDRSZ + sizeof(inet_struct));
+	dst = (inet *) palloc0(sizeof(inet));
 
 	if (ip_family(ip) == PGSQL_AF_INET)
 		maxbytes = 4;
@@ -930,9 +936,7 @@ network_hostmask(PG_FUNCTION_ARGS)
 
 	ip_family(dst) = ip_family(ip);
 	ip_bits(dst) = ip_maxbits(ip);
-	SET_VARSIZE(dst, VARHDRSZ +
-		((char *) ip_addr(dst) - (char *) VARDATA(dst)) +
-		ip_addrsize(dst));
+	SET_INET_VARSIZE(dst);
 
 	PG_RETURN_INET_P(dst);
 }
@@ -1259,7 +1263,7 @@ inetnot(PG_FUNCTION_ARGS)
 	inet	   *ip = PG_GETARG_INET_P(0);
 	inet	   *dst;
 
-	dst = (inet *) palloc0(VARHDRSZ + sizeof(inet_struct));
+	dst = (inet *) palloc0(sizeof(inet));
 
 	{
 		int			nb = ip_addrsize(ip);
@@ -1272,9 +1276,7 @@ inetnot(PG_FUNCTION_ARGS)
 	ip_bits(dst) = ip_bits(ip);
 
 	ip_family(dst) = ip_family(ip);
-	SET_VARSIZE(dst, VARHDRSZ +
-		((char *) ip_addr(dst) - (char *) VARDATA(dst)) +
-		ip_addrsize(dst));
+	SET_INET_VARSIZE(dst);
 
 	PG_RETURN_INET_P(dst);
 }
@@ -1287,7 +1289,7 @@ inetand(PG_FUNCTION_ARGS)
 	inet	   *ip2 = PG_GETARG_INET_P(1);
 	inet	   *dst;
 
-	dst = (inet *) palloc0(VARHDRSZ + sizeof(inet_struct));
+	dst = (inet *) palloc0(sizeof(inet));
 
 	if (ip_family(ip) != ip_family(ip2))
 		ereport(ERROR,
@@ -1306,9 +1308,7 @@ inetand(PG_FUNCTION_ARGS)
 	ip_bits(dst) = Max(ip_bits(ip), ip_bits(ip2));
 
 	ip_family(dst) = ip_family(ip);
-	SET_VARSIZE(dst, VARHDRSZ +
-		((char *) ip_addr(dst) - (char *) VARDATA(dst)) +
-		ip_addrsize(dst));
+	SET_INET_VARSIZE(dst);
 
 	PG_RETURN_INET_P(dst);
 }
@@ -1321,7 +1321,7 @@ inetor(PG_FUNCTION_ARGS)
 	inet	   *ip2 = PG_GETARG_INET_P(1);
 	inet	   *dst;
 
-	dst = (inet *) palloc0(VARHDRSZ + sizeof(inet_struct));
+	dst = (inet *) palloc0(sizeof(inet));
 
 	if (ip_family(ip) != ip_family(ip2))
 		ereport(ERROR,
@@ -1340,9 +1340,7 @@ inetor(PG_FUNCTION_ARGS)
 	ip_bits(dst) = Max(ip_bits(ip), ip_bits(ip2));
 
 	ip_family(dst) = ip_family(ip);
-	SET_VARSIZE(dst, VARHDRSZ +
-		((char *) ip_addr(dst) - (char *) VARDATA(dst)) +
-		ip_addrsize(dst));
+	SET_INET_VARSIZE(dst);
 
 	PG_RETURN_INET_P(dst);
 }
@@ -1353,7 +1351,7 @@ internal_inetpl(inet *ip, int64 addend)
 {
 	inet	   *dst;
 
-	dst = (inet *) palloc0(VARHDRSZ + sizeof(inet_struct));
+	dst = (inet *) palloc0(sizeof(inet));
 
 	{
 		int			nb = ip_addrsize(ip);
@@ -1391,12 +1389,10 @@ internal_inetpl(inet *ip, int64 addend)
 					(errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
 					 errmsg("result is out of range")));
 	}
-	ip_bits(dst) = ip_bits(ip);
 
+	ip_bits(dst) = ip_bits(ip);
 	ip_family(dst) = ip_family(ip);
-	SET_VARSIZE(dst, VARHDRSZ +
-		((char *) ip_addr(dst) - (char *) VARDATA(dst)) +
-		ip_addrsize(dst));
+	SET_INET_VARSIZE(dst);
 
 	return dst;
 }