MonetDB: default - Avoid dangling pointer

[Martin Kersten]

Changeset: f3a4f90a6a9b for MonetDB
URL: http://dev.monetdb.org/hg/MonetDB?cmd=changeset;node=f3a4f90a6a9b
Modified Files:
        monetdb5/mal/mal_builder.c
        monetdb5/mal/mal_instruction.c
Branch: default
Log Message:

Avoid dangling pointer
Don't free an instruction that is potentially referenced from block


diffs (123 lines):

diff --git a/monetdb5/mal/mal_builder.c b/monetdb5/mal/mal_builder.c
--- a/monetdb5/mal/mal_builder.c
+++ b/monetdb5/mal/mal_builder.c
@@ -27,15 +27,11 @@ newAssignment(MalBlkPtr mb)
 
        if ( q == NULL)
                return NULL;
-       if ((getArg(q,0)= newTmpVariable(mb,TYPE_any)) < 0) {
+       if ((getArg(q,0)= newTmpVariable(mb,TYPE_any)) < 0 || mb->errors) {
                freeInstruction(q);
                return NULL;
        }
        pushInstruction(mb, q);
-       if (mb->errors) {
-               freeInstruction(q);
-               return NULL;
-       }
        return q;
 }
 
@@ -47,15 +43,11 @@ newStmt(MalBlkPtr mb, const char *module
        if ( q == NULL)
                return NULL;
        setDestVar(q, newTmpVariable(mb, TYPE_any));
-       if (getDestVar(q) < 0) {
+       if (getDestVar(q) < 0 || mb->errors) {
                freeInstruction(q);
                return NULL;
        }
        pushInstruction(mb, q);
-       if (mb->errors) {
-               freeInstruction(q);
-               return NULL;
-       }
        return q;
 }
 
@@ -66,16 +58,12 @@ newReturnStmt(MalBlkPtr mb)
 
        if ( q == NULL)
                return NULL;
-       if ((getArg(q,0)= newTmpVariable(mb,TYPE_any)) < 0) {
+       if ((getArg(q,0)= newTmpVariable(mb,TYPE_any)) < 0 || mb->errors) {
                freeInstruction(q);
                return NULL;
        }
        q->barrier= RETURNsymbol;
        pushInstruction(mb, q);
-       if (mb->errors) {
-               freeInstruction(q);
-               return NULL;
-       }
        return q;
 }
 
@@ -115,10 +103,6 @@ newComment(MalBlkPtr mb, const char *val
                return NULL;
        }
        pushInstruction(mb, q);
-       if (mb->errors) {
-               freeInstruction(q);
-               return NULL;
-       }
        return q;
 }
 
@@ -132,7 +116,7 @@ newCatchStmt(MalBlkPtr mb, str nme)
                return NULL;
        q->barrier = CATCHsymbol;
        if ( i< 0) {
-               if ((getArg(q,0)= newVariable(mb, nme, strlen(nme),TYPE_str)) < 
0) {
+               if ((getArg(q,0)= newVariable(mb, nme, strlen(nme),TYPE_str)) < 
0 || mb->errors) {
                        freeInstruction(q);
                        return NULL;
                }
@@ -140,6 +124,7 @@ newCatchStmt(MalBlkPtr mb, str nme)
        } else getArg(q,0) = i;
        return q;
 }
+
 InstrPtr
 newRaiseStmt(MalBlkPtr mb, str nme)
 {
@@ -150,7 +135,7 @@ newRaiseStmt(MalBlkPtr mb, str nme)
                return NULL;
        q->barrier = RAISEsymbol;
        if ( i< 0) {
-               if ((getArg(q,0)= newVariable(mb, nme, strlen(nme),TYPE_str)) < 
0) {
+               if ((getArg(q,0)= newVariable(mb, nme, strlen(nme),TYPE_str)) < 
0 || mb->errors) {
                        freeInstruction(q);
                        return NULL;
                }
@@ -169,17 +154,13 @@ newExitStmt(MalBlkPtr mb, str nme)
                return NULL;
        q->barrier = EXITsymbol;
        if ( i< 0) {
-               if ((getArg(q,0)= newVariable(mb, nme,strlen(nme),TYPE_str)) < 
0) {
+               if ((getArg(q,0)= newVariable(mb, nme,strlen(nme),TYPE_str)) < 
0 || mb->errors) {
                        freeInstruction(q);
                        return NULL;
                }
        } else
                getArg(q,0) = i;
     pushInstruction(mb, q);
-       if (mb->errors) {
-               freeInstruction(q);
-               return NULL;
-       }
        return q;
 }
 
diff --git a/monetdb5/mal/mal_instruction.c b/monetdb5/mal/mal_instruction.c
--- a/monetdb5/mal/mal_instruction.c
+++ b/monetdb5/mal/mal_instruction.c
@@ -658,6 +658,8 @@ makeVarSpace(MalBlkPtr mb)
 
                new = (VarRecord*) GDKrealloc(mb->var, s * sizeof(VarRecord));
                if (new == NULL) {
+                       // the only place to return an error signal at this 
stage.
+                       // The Client context should be passed around more 
deeply
                        mb->errors++;
                        showException(GDKout, MAL, "newMalBlk",MAL_MALLOC_FAIL);
                        return -1;
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