[lcd4linux @ 2006-01-21 09:40:20 by reinelt]

Big Memory Leak in Evaluator fixed (thanks to Oliver Gehrke)

git-svn-id: https://ssl.bulix.org/svn/lcd4linux/trunk@617 3ae390bd-cb1e-0410-b409-cd5a39f66f1f

diff --git a/evaluator.c b/evaluator.c
index abb32786d1f8e44c713c35cee1f35eb39418fce6..e4493b315e109311d142bcf031356af143d0c464 100644 (file)
--- a/evaluator.c
+++ b/evaluator.c
@@ -1,4 +1,4 @@
-/* $Id: evaluator.c,v 1.25 2005/05/08 04:32:44 reinelt Exp $
+/* $Id: evaluator.c,v 1.26 2006/01/21 09:40:20 reinelt Exp $
  *
  * expression evaluation
  *
@@ -23,6 +23,9 @@
  *
  *
  * $Log: evaluator.c,v $
+ * Revision 1.26  2006/01/21 09:40:20  reinelt
+ * Big Memory Leak in Evaluator fixed (thanks to Oliver Gehrke)
+ *
  * Revision 1.25  2005/05/08 04:32:44  reinelt
  * CodingStyle added and applied
  *
@@ -340,29 +343,6 @@ static RESULT *NewResult(void)
 }
 
 
-static RESULT *DupResult(RESULT * result)
-{
-    RESULT *result2;
-
-    if ((result2 = NewResult()) == NULL)
-       return NULL;
-
-    result2->type = result->type;
-    result2->number = result->number;
-
-    if (result->length >= 0) {
-       result2->length = result->length;
-       result2->string = malloc(result2->length);
-       strcpy(result2->string, result->string);
-    } else {
-       result2->length = -1;
-       result2->string = NULL;
-    }
-
-    return result2;
-}
-
-
 RESULT *SetResult(RESULT ** result, const int type, const void *value)
 {
     if (*result == NULL) {
@@ -392,7 +372,7 @@ RESULT *SetResult(RESULT ** result, const int type, const void *value)
            (*result)->length = CHUNK_SIZE * (len / CHUNK_SIZE + 1) - 1;
            (*result)->string = malloc((*result)->length + 1);
        }
-       strcpy((*result)->string, value);
+       strncpy((*result)->string, value, (*result)->length + 1);
     } else {
        error("Evaluator: internal error: invalid result type %d", type);
        return NULL;
@@ -402,6 +382,36 @@ RESULT *SetResult(RESULT ** result, const int type, const void *value)
 }
 
 
+static RESULT *CopyResult(RESULT ** result, RESULT * value)
+{
+    if (*result == NULL) {
+       if ((*result = NewResult()) == NULL)
+           return NULL;
+    }
+
+    (*result)->type = value->type;
+    (*result)->number = value->number;
+
+    if (value->string == NULL) {
+       if ((*result)->string)
+           free((*result)->string);
+       (*result)->string = NULL;
+       (*result)->length = -1;
+    } else {
+       /* is buffer large enough? */
+       if ((*result)->string == NULL || value->length > (*result)->length) {
+           if ((*result)->string)
+               free((*result)->string);
+           (*result)->length = value->length;
+           (*result)->string = malloc((*result)->length + 1);
+           /* length does not count the trailing \0 */
+       }
+       strncpy((*result)->string, value->string, (*result)->length + 1);
+    }
+    return *result;
+}
+
+
 double R2N(RESULT * result)
 {
     if (result == NULL) {
@@ -440,8 +450,8 @@ char *R2S(RESULT * result)
        if (result->string)
            free(result->string);
        result->length = CHUNK_SIZE - 1;
-       result->string = malloc(CHUNK_SIZE);
-       snprintf(result->string, CHUNK_SIZE, "%g", result->number);
+       result->string = malloc(result->length+1);
+       snprintf(result->string, result->length, "%g", result->number);
        return result->string;
     }
 
@@ -483,15 +493,15 @@ int SetVariable(const char *name, RESULT * value)
 
     V = FindVariable(name);
     if (V != NULL) {
-       FreeResult(V->value);
-       V->value = DupResult(value);
+       CopyResult (&V->value, value);
        return 1;
     }
 
     nVariable++;
     Variable = realloc(Variable, nVariable * sizeof(VARIABLE));
     Variable[nVariable - 1].name = strdup(name);
-    Variable[nVariable - 1].value = DupResult(value);
+    Variable[nVariable - 1].value = NULL;
+    CopyResult (&Variable[nVariable - 1].value, value);
 
     qsort(Variable, nVariable, sizeof(VARIABLE), SortVariable);
 
@@ -1064,8 +1074,7 @@ static int EvalTree(NODE * Root)
        return 0;
 
     case T_VARIABLE:
-       DelResult(Root->Result);
-       Root->Result = DupResult(Root->Variable->value);
+       CopyResult (&Root->Result, Root->Variable->value);
        return 0;
 
     case T_FUNCTION:
@@ -1097,8 +1106,7 @@ static int EvalTree(NODE * Root)
            break;
 
        case O_SET:             /* variable assignment */
-           DelResult(Root->Variable->value);
-           Root->Variable->value = DupResult(Root->Child[0]->Result);
+           CopyResult(&Root->Variable->value, Root->Child[0]->Result);
            type = Root->Child[0]->Result->type;
            number = Root->Child[0]->Result->number;
            string = Root->Child[0]->Result->string;
@@ -1297,9 +1305,9 @@ int Eval(void *tree, RESULT * result)
     result->number = Tree->Result->number;
     result->length = Tree->Result->length;
     if (result->length >= 0) {
-       result->string = malloc(result->length);
+       result->string = malloc(result->length+1);
        if (Tree->Result->string != NULL)
-           strcpy(result->string, Tree->Result->string);
+           strncpy(result->string, Tree->Result->string, result->length);
        else
            result->string[0] = '\0';
     } else {