a safe variant of vlistInqVarName() [patch 8/14 from Nathanael]

src/cdi.h

@@ -486,6 +486,9 @@ void    vlistDefVarName(int vlistID, int varID, const char *name);
 /*      vlistInqVarName: Get the name of a Variable */
 void    vlistInqVarName(int vlistID, int varID, char *name);
 
+/*      vlistCopyVarName: Safe and convenient version of vlistInqVarName */
+char*   vlistCopyVarName(int vlistId, int varId);
+
 /*      vlistDefVarStdname: Define the standard name of a Variable */
 void    vlistDefVarStdname(int vlistID, int varID, const char *stdname);
 

src/vlist.h

@@ -150,6 +150,7 @@ vlist_t;
 
 
 vlist_t *vlist_to_pointer(int vlistID);
+void vlistCheckVarID(const char *caller, int vlistID, int varID);
 const char *vlistInqVarNamePtr(int vlistID, int varID);
 const char *vlistInqVarLongnamePtr(int vlistID, int varID);
 const char *vlistInqVarStdnamePtr(int vlistID, int varID);

src/vlist_var.c

@@ -14,6 +14,7 @@
 #include "namespace.h"
 #include "serialize.h"
 #include "error.h"
+#include "proprietarySystemWorkarounds.h"
 
 static
 void vlistvarInitEntry(int vlistID, int varID)
@@ -128,7 +129,6 @@ int vlistvarNewEntry(int vlistID)
   return (varID);
 }
 
-static
 void vlistCheckVarID(const char *caller, int vlistID, int varID)
 {
   vlist_t *vlistptr = vlist_to_pointer(vlistID);
@@ -501,6 +501,49 @@ void vlistInqVarName(int vlistID, int varID, char *name)
   return;
 }
 
+/*
+@Function vlistCopyVarName
+@Tatle    Get the name of a Variable in a safe way
+
+@Prototype char* vlistCopyVarName(int vlistId, int varId)
+@Parameter
+    @Item  vlistID  Variable list ID, from a previous call to @fref{vlistCreate} or @fref{streamInqVlist}.
+    @Item  varID    Variable identifier.
+
+@Return A pointer to a malloc'ed string. Must be cleaned up with free().
+
+@Description
+This is the buffer overflow immune version of vlistInqVarName().
+The memory for the returned string is allocated to fit the string via malloc().
+
+@EndFunction
+*/
+char* vlistCopyVarName(int vlistId, int varId)
+{
+  vlist_t* vlistptr = vlist_to_pointer(vlistId);
+  vlistCheckVarID(__func__, vlistId, varId);
+
+  //If a name is set in the variable description, use that.
+  const char* name = vlistptr->vars[varId].name;
+  if(name) return myStrDup(name);
+
+  //Otherwise we check if we should use the table of parameter descriptions.
+  int param = vlistptr->vars[varId].param;
+  int discipline, category, number;
+  cdiDecodeParam(param, &number, &category, &discipline);
+  if(discipline == 255)
+    {
+      int tableId = vlistptr->vars[varId].tableID;
+      if(( name = tableInqParNamePtr(tableId, number) )) return myStrDup(name);
+
+      //No luck, fall back to outputting a name of the format "var<num>".
+      return myAsprintf("var%d", number);
+    }
+
+  //Finally, we fall back to outputting a name of the format "param<num>.<cat>.<dis>".
+  return myAsprintf("param%d.%d.%d", number, category, discipline);
+}
+
 /*
 @Function  vlistInqVarLongname
 @Title     Get the longname of a Variable