Don't assume free(NULL) is OK. Yes, I know ANSI C says it is.

tglsfdc · tglsfdc · commit df3f152ed723 · 2001-06-13T19:52:33.000Z
diff --git a/src/backend/utils/init/miscinit.c b/src/backend/utils/init/miscinit.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/utils/init/miscinit.c,v 1.69 2001/06/06 17:07:46 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/utils/init/miscinit.c,v 1.70 2001/06/13 19:52:33 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -36,7 +36,6 @@
 #ifdef CYR_RECODE
 unsigned char RecodeForwTable[128];
 unsigned char RecodeBackTable[128];
-
 #endif
 
 ProcessingMode Mode = InitProcessing;
@@ -82,7 +81,11 @@ IgnoreSystemIndexes(bool mode)
 void
 SetDatabasePath(const char *path)
 {
-	free(DatabasePath);
+	if (DatabasePath)
+	{
+		free(DatabasePath);
+		DatabasePath = NULL;
+	}
 	/* use strdup since this is done before memory contexts are set up */
 	if (path)
 	{
@@ -94,7 +97,12 @@ SetDatabasePath(const char *path)
 void
 SetDatabaseName(const char *name)
 {
-	free(DatabaseName);
+	if (DatabaseName)
+	{
+		free(DatabaseName);
+		DatabaseName = NULL;
+	}
+	/* use strdup since this is done before memory contexts are set up */
 	if (name)
 	{
 		DatabaseName = strdup(name);
@@ -112,8 +120,6 @@ SetDataDir(const char *dir)
 	char	   *new;
 
 	AssertArg(dir);
-	if (DataDir)
-		free(DataDir);
 
 	if (dir[0] != '/')
 	{
@@ -155,6 +161,8 @@ SetDataDir(const char *dir)
 			elog(FATAL, "out of memory");
 	}
 
+	if (DataDir)
+		free(DataDir);
 	DataDir = new;
 }
 

Original file line number	Diff line number	Diff line change
`@@ -8,7 +8,7 @@`
`8`	`8`	`*`
`9`	`9`	`*`
`10`	`10`	`* IDENTIFICATION`
`11`		`- * $Header: /cvsroot/pgsql/src/backend/utils/init/miscinit.c,v 1.69 2001/06/06 17:07:46 tgl Exp $`
	`11`	`+ * $Header: /cvsroot/pgsql/src/backend/utils/init/miscinit.c,v 1.70 2001/06/13 19:52:33 tgl Exp $`
`12`	`12`	`*`
`13`	`13`	`*-------------------------------------------------------------------------`
`14`	`14`	`*/`
`@@ -36,7 +36,6 @@`
`36`	`36`	`#ifdef CYR_RECODE`
`37`	`37`	`unsigned char RecodeForwTable[128];`
`38`	`38`	`unsigned char RecodeBackTable[128];`
`39`		`-`
`40`	`39`	`#endif`
`41`	`40`
`42`	`41`	`ProcessingMode Mode = InitProcessing;`
`@@ -82,7 +81,11 @@ IgnoreSystemIndexes(bool mode)`
`82`	`81`	`void`
`83`	`82`	`SetDatabasePath(const char *path)`
`84`	`83`	`{`
`85`		`- free(DatabasePath);`
	`84`	`+ if (DatabasePath)`
	`85`	`+ {`
	`86`	`+ free(DatabasePath);`
	`87`	`+ DatabasePath = NULL;`
	`88`	`+ }`
`86`	`89`	`/* use strdup since this is done before memory contexts are set up */`
`87`	`90`	`if (path)`
`88`	`91`	`{`
`@@ -94,7 +97,12 @@ SetDatabasePath(const char *path)`
`94`	`97`	`void`
`95`	`98`	`SetDatabaseName(const char *name)`
`96`	`99`	`{`
`97`		`- free(DatabaseName);`
	`100`	`+ if (DatabaseName)`
	`101`	`+ {`
	`102`	`+ free(DatabaseName);`
	`103`	`+ DatabaseName = NULL;`
	`104`	`+ }`
	`105`	`+ /* use strdup since this is done before memory contexts are set up */`
`98`	`106`	`if (name)`
`99`	`107`	`{`
`100`	`108`	`DatabaseName = strdup(name);`
`@@ -112,8 +120,6 @@ SetDataDir(const char *dir)`
`112`	`120`	`char *new;`
`113`	`121`
`114`	`122`	`AssertArg(dir);`
`115`		`- if (DataDir)`
`116`		`- free(DataDir);`
`117`	`123`
`118`	`124`	`if (dir[0] != '/')`
`119`	`125`	`{`
`@@ -155,6 +161,8 @@ SetDataDir(const char *dir)`
`155`	`161`	`elog(FATAL, "out of memory");`
`156`	`162`	`}`
`157`	`163`
	`164`	`+ if (DataDir)`
	`165`	`+ free(DataDir);`
`158`	`166`	`DataDir = new;`
`159`	`167`	`}`
`160`	`168`