r.kappa: Fix Resource Leak issues (#6224)

Author: ShubhamDesai

raster/r.kappa/mask.c

@@ -21,7 +21,7 @@ char *maskinfo(void)
 
     results = NULL;
     if (!Rast_mask_status(mask_name, mask_mapset, NULL, NULL, NULL))
-        return "none";
+        return G_store("none");
     if (Rast_get_reclass(mask_name, mask_mapset, &reclass) <= 0) {
         snprintf(text, sizeof(text), "%s in %s", mask_name, mask_mapset);
         return append(results, text);

raster/r.kappa/print_header.c

@@ -21,8 +21,10 @@ void print_header(void)
     snprintf(buf, sizeof(buf), "LOCATION: %s\t\t\t\t%s", G_location(),
              G_date());
     fprintf(fd, "%s\n", buf);
-    if ((mask = maskinfo()))
+    if ((mask = maskinfo())) {
         snprintf(buf, sizeof(buf), "MASK: %s", mask);
+        G_free(mask);
+    }
 
     fprintf(fd, "%s\n", buf);
     fprintf(fd, "MAPS: ");

raster/r.kappa/stats.c

@@ -46,10 +46,12 @@ int stats(void)
     argv[argc++] = "-cin";
 
     argv[argc++] = "separator=:";
+    char *f_mname = G_fully_qualified_name(mname, mmapset);
+    char *f_rname = G_fully_qualified_name(rname, rmapset);
 
-    snprintf(buf, sizeof(buf), "input=%s,%s",
-             G_fully_qualified_name(mname, mmapset),
-             G_fully_qualified_name(rname, rmapset));
+    snprintf(buf, sizeof(buf), "input=%s,%s", f_mname, f_rname);
+    G_free(f_mname);
+    G_free(f_rname);
     argv[argc++] = buf;
 
     argv[argc++] = SF_REDIRECT_FILE;