Replace strncpy with strlcpy in selected places that seem possibly relevant

to performance.  (A wholesale effort to get rid of strncpy should be
undertaken sometime, but not during beta.)  This commit also fixes dynahash.c
to correctly truncate overlength string keys for hashtables, so that its
callers don't have to anymore.

Author: tglsfdc

src/backend/commands/prepare.c

@@ -10,7 +10,7 @@
  * Copyright (c) 2002-2006, PostgreSQL Global Development Group
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/commands/prepare.c,v 1.64 2006/09/07 22:52:00 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/commands/prepare.c,v 1.65 2006/09/27 18:40:09 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -314,18 +314,14 @@ StorePreparedStatement(const char *stmt_name,
 	MemoryContext oldcxt,
 				entrycxt;
 	char	   *qstring;
-	char		key[NAMEDATALEN];
 	bool		found;
 
 	/* Initialize the hash table, if necessary */
 	if (!prepared_queries)
 		InitQueryHashTable();
 
 	/* Check for pre-existing entry of same name */
-	/* See notes in FetchPreparedStatement */
-	StrNCpy(key, stmt_name, sizeof(key));
-
-	hash_search(prepared_queries, key, HASH_FIND, &found);
+	hash_search(prepared_queries, stmt_name, HASH_FIND, &found);
 
 	if (found)
 		ereport(ERROR,
@@ -355,7 +351,7 @@ StorePreparedStatement(const char *stmt_name,
 
 	/* Now we can add entry to hash table */
 	entry = (PreparedStatement *) hash_search(prepared_queries,
-											  key,
+											  stmt_name,
 											  HASH_ENTER,
 											  &found);
 
@@ -384,27 +380,17 @@ StorePreparedStatement(const char *stmt_name,
 PreparedStatement *
 FetchPreparedStatement(const char *stmt_name, bool throwError)
 {
-	char		key[NAMEDATALEN];
 	PreparedStatement *entry;
 
 	/*
 	 * If the hash table hasn't been initialized, it can't be storing
 	 * anything, therefore it couldn't possibly store our plan.
 	 */
 	if (prepared_queries)
-	{
-		/*
-		 * We can't just use the statement name as supplied by the user: the
-		 * hash package is picky enough that it needs to be NUL-padded out to
-		 * the appropriate length to work correctly.
-		 */
-		StrNCpy(key, stmt_name, sizeof(key));
-
 		entry = (PreparedStatement *) hash_search(prepared_queries,
-												  key,
+												  stmt_name,
 												  HASH_FIND,
 												  NULL);
-	}
 	else
 		entry = NULL;
 

src/backend/nodes/read.c

@@ -9,7 +9,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/nodes/read.c,v 1.48 2006/03/05 15:58:28 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/nodes/read.c,v 1.49 2006/09/27 18:40:09 tgl Exp $
  *
  * HISTORY
  *	  AUTHOR			DATE			MAJOR EVENT
@@ -408,7 +408,7 @@ nodeRead(char *token, int tok_len)
 				char	   *val = palloc(tok_len);
 
 				/* skip leading 'b' */
-				strncpy(val, token + 1, tok_len - 1);
+				memcpy(val, token + 1, tok_len - 1);
 				val[tok_len - 1] = '\0';
 				result = (Node *) makeBitString(val);
 				break;

src/backend/storage/ipc/shmem.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/storage/ipc/shmem.c,v 1.95 2006/08/01 19:03:11 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/storage/ipc/shmem.c,v 1.96 2006/09/27 18:40:09 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -456,13 +456,9 @@ ShmemInitHash(const char *name, /* table string name for shmem index */
 void *
 ShmemInitStruct(const char *name, Size size, bool *foundPtr)
 {
-	ShmemIndexEnt *result,
-				item;
+	ShmemIndexEnt *result;
 	void	   *structPtr;
 
-	strncpy(item.key, name, SHMEM_INDEX_KEYSIZE);
-	item.location = BAD_LOCATION;
-
 	LWLockAcquire(ShmemIndexLock, LW_EXCLUSIVE);
 
 	if (!ShmemIndex)
@@ -498,7 +494,7 @@ ShmemInitStruct(const char *name, Size size, bool *foundPtr)
 
 	/* look it up in the shmem index */
 	result = (ShmemIndexEnt *)
-		hash_search(ShmemIndex, (void *) &item, HASH_ENTER_NULL, foundPtr);
+		hash_search(ShmemIndex, name, HASH_ENTER_NULL, foundPtr);
 
 	if (!result)
 	{
@@ -533,12 +529,13 @@ ShmemInitStruct(const char *name, Size size, bool *foundPtr)
 		{
 			/* out of memory */
 			Assert(ShmemIndex);
-			hash_search(ShmemIndex, (void *) &item, HASH_REMOVE, NULL);
+			hash_search(ShmemIndex, name, HASH_REMOVE, NULL);
 			LWLockRelease(ShmemIndexLock);
 
 			ereport(WARNING,
 					(errcode(ERRCODE_OUT_OF_MEMORY),
-			errmsg("could not allocate shared memory segment \"%s\"", name)));
+					 errmsg("could not allocate shared memory segment \"%s\"",
+							name)));
 			*foundPtr = FALSE;
 			return NULL;
 		}

src/backend/utils/error/elog.c

@@ -42,7 +42,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/utils/error/elog.c,v 1.173 2006/07/14 14:52:25 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/utils/error/elog.c,v 1.174 2006/09/27 18:40:09 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1225,6 +1225,7 @@ write_syslog(int level, const char *line)
 		while (len > 0)
 		{
 			char		buf[PG_SYSLOG_LIMIT + 1];
+			const char *nlpos;
 			int			buflen;
 			int			i;
 
@@ -1236,12 +1237,15 @@ write_syslog(int level, const char *line)
 				continue;
 			}
 
-			strncpy(buf, line, PG_SYSLOG_LIMIT);
-			buf[PG_SYSLOG_LIMIT] = '\0';
-			if (strchr(buf, '\n') != NULL)
-				*strchr(buf, '\n') = '\0';
-
-			buflen = strlen(buf);
+			/* copy one line, or as much as will fit, to buf */
+			nlpos = strchr(line, '\n');
+			if (nlpos != NULL)
+				buflen = nlpos - line;
+			else
+				buflen = len;
+			buflen = Min(buflen, PG_SYSLOG_LIMIT);
+			memcpy(buf, line, buflen);
+			buf[buflen] = '\0';
 
 			/* trim to multibyte letter boundary */
 			buflen = pg_mbcliplen(buf, buflen, buflen);

src/backend/utils/fmgr/dfmgr.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/utils/fmgr/dfmgr.c,v 1.89 2006/08/16 04:32:48 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/utils/fmgr/dfmgr.c,v 1.90 2006/09/27 18:40:09 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -594,7 +594,6 @@ find_rendezvous_variable(const char *varName)
 {
 	static HTAB         *rendezvousHash = NULL;
 
-	char			     key[NAMEDATALEN];
 	rendezvousHashEntry *hentry;
 	bool				 found;
 
@@ -612,12 +611,9 @@ find_rendezvous_variable(const char *varName)
 									 HASH_ELEM);
 	}
 
-	/* Turn the varName into a fixed-size string */
-	StrNCpy(key, varName, sizeof(key));
-
 	/* Find or create the hashtable entry for this varName */
 	hentry = (rendezvousHashEntry *) hash_search(rendezvousHash,
-												 key,
+												 varName,
 												 HASH_ENTER,
 												 &found);
 

src/backend/utils/hash/dynahash.c

@@ -26,7 +26,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/utils/hash/dynahash.c,v 1.71 2006/08/14 12:39:55 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/utils/hash/dynahash.c,v 1.72 2006/09/27 18:40:09 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -209,6 +209,20 @@ DynaHashAlloc(Size size)
 }
 
 
+/*
+ * HashCompareFunc for string keys
+ *
+ * Because we copy keys with strlcpy(), they will be truncated at keysize-1
+ * bytes, so we can only compare that many ... hence strncmp is almost but
+ * not quite the right thing.
+ */
+static int
+string_compare(const char *key1, const char *key2, Size keysize)
+{
+	return strncmp(key1, key2, keysize - 1);
+}
+
+
 /************************** CREATE ROUTINES **********************/
 
 /*
@@ -273,24 +287,24 @@ hash_create(const char *tabname, long nelem, HASHCTL *info, int flags)
 		hashp->hash = string_hash;		/* default hash function */
 
 	/*
-	 * If you don't specify a match function, it defaults to strncmp() if you
-	 * used string_hash (either explicitly or by default) and to memcmp()
-	 * otherwise.  (Prior to PostgreSQL 7.4, memcmp() was always used.)
+	 * If you don't specify a match function, it defaults to string_compare
+	 * if you used string_hash (either explicitly or by default) and to memcmp
+	 * otherwise.  (Prior to PostgreSQL 7.4, memcmp was always used.)
 	 */
 	if (flags & HASH_COMPARE)
 		hashp->match = info->match;
 	else if (hashp->hash == string_hash)
-		hashp->match = (HashCompareFunc) strncmp;
+		hashp->match = (HashCompareFunc) string_compare;
 	else
 		hashp->match = memcmp;
 
 	/*
-	 * Similarly, the key-copying function defaults to strncpy() or memcpy().
+	 * Similarly, the key-copying function defaults to strlcpy or memcpy.
 	 */
 	if (flags & HASH_KEYCOPY)
 		hashp->keycopy = info->keycopy;
 	else if (hashp->hash == string_hash)
-		hashp->keycopy = (HashCopyFunc) strncpy;
+		hashp->keycopy = (HashCopyFunc) strlcpy;
 	else
 		hashp->keycopy = memcpy;
 

src/backend/utils/hash/hashfn.c

@@ -9,7 +9,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/utils/hash/hashfn.c,v 1.27 2006/07/14 14:52:25 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/utils/hash/hashfn.c,v 1.28 2006/09/27 18:40:09 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -27,8 +27,16 @@
 uint32
 string_hash(const void *key, Size keysize)
 {
+	/*
+	 * If the string exceeds keysize-1 bytes, we want to hash only that many,
+	 * because when it is copied into the hash table it will be truncated at
+	 * that length.
+	 */
+	Size	s_len = strlen((const char *) key);
+
+	s_len = Min(s_len, keysize-1);
 	return DatumGetUInt32(hash_any((const unsigned char *) key,
-								   (int) strlen((const char *) key)));
+								   (int) s_len));
 }
 
 /*

src/backend/utils/misc/ps_status.c

@@ -5,7 +5,7 @@
  * to contain some useful information. Mechanism differs wildly across
  * platforms.
  *
- * $PostgreSQL: pgsql/src/backend/utils/misc/ps_status.c,v 1.31 2006/06/27 22:16:44 momjian Exp $
+ * $PostgreSQL: pgsql/src/backend/utils/misc/ps_status.c,v 1.32 2006/09/27 18:40:10 tgl Exp $
  *
  * Copyright (c) 2000-2006, PostgreSQL Global Development Group
  * various details abducted from various places
@@ -300,7 +300,7 @@ set_ps_display(const char *activity, bool force)
 #endif
 
 	/* Update ps_buffer to contain both fixed part and activity */
-	StrNCpy(ps_buffer + ps_buffer_fixed_size, activity,
+	strlcpy(ps_buffer + ps_buffer_fixed_size, activity,
 			ps_buffer_size - ps_buffer_fixed_size);
 
 	/* Transmit new setting to kernel, if necessary */

src/backend/utils/mmgr/portalmem.c

@@ -12,7 +12,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/utils/mmgr/portalmem.c,v 1.94 2006/09/07 22:52:01 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/utils/mmgr/portalmem.c,v 1.95 2006/09/27 18:40:10 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -54,12 +54,10 @@ static HTAB *PortalHashTable = NULL;
 
 #define PortalHashTableLookup(NAME, PORTAL) \
 do { \
-	PortalHashEnt *hentry; char key[MAX_PORTALNAME_LEN]; \
+	PortalHashEnt *hentry; \
 	\
-	MemSet(key, 0, MAX_PORTALNAME_LEN); \
-	StrNCpy(key, NAME, MAX_PORTALNAME_LEN); \
 	hentry = (PortalHashEnt *) hash_search(PortalHashTable, \
-										   key, HASH_FIND, NULL);	\
+										   (NAME), HASH_FIND, NULL); \
 	if (hentry) \
 		PORTAL = hentry->portal; \
 	else \
@@ -68,12 +66,10 @@ do { \
 
 #define PortalHashTableInsert(PORTAL, NAME) \
 do { \
-	PortalHashEnt *hentry; bool found; char key[MAX_PORTALNAME_LEN]; \
+	PortalHashEnt *hentry; bool found; \
 	\
-	MemSet(key, 0, MAX_PORTALNAME_LEN); \
-	StrNCpy(key, NAME, MAX_PORTALNAME_LEN); \
 	hentry = (PortalHashEnt *) hash_search(PortalHashTable, \
-										   key, HASH_ENTER, &found);	\
+										   (NAME), HASH_ENTER, &found);	\
 	if (found) \
 		elog(ERROR, "duplicate portal name"); \
 	hentry->portal = PORTAL; \
@@ -83,12 +79,10 @@ do { \
 
 #define PortalHashTableDelete(PORTAL) \
 do { \
-	PortalHashEnt *hentry; char key[MAX_PORTALNAME_LEN]; \
+	PortalHashEnt *hentry; \
 	\
-	MemSet(key, 0, MAX_PORTALNAME_LEN); \
-	StrNCpy(key, PORTAL->name, MAX_PORTALNAME_LEN); \
 	hentry = (PortalHashEnt *) hash_search(PortalHashTable, \
-										   key, HASH_REMOVE, NULL); \
+										   PORTAL->name, HASH_REMOVE, NULL); \
 	if (hentry == NULL) \
 		elog(WARNING, "trying to delete portal name that does not exist"); \
 } while(0)