replaced strlcat with compat function

Closes #8

CMakeLists.txt

@@ -94,6 +94,7 @@ add_executable(fh
         src/update.c src/update.h
         src/version.c src/version.h
         src/cjson/cJSON.c src/cjson/cJSON.h
-        src/cjson/helpers.c src/cjson/helpers.h)
+        src/cjson/helpers.c src/cjson/helpers.h
+        src/memsafe.c src/memsafe.h)
 
 target_link_libraries(fh ${USE_LIB_M})

src/cjson/helpers.c

@@ -6,6 +6,7 @@
 #include <stdlib.h>
 #include <string.h>
 #include "helpers.h"
+#include "../memsafe.h"
 
 
 void jsonAddIntToArray(cJSON *array, const char *arrayName, int value) {
@@ -102,7 +103,7 @@ void jsonGetString(cJSON *obj, const char *property, char *dst, int size) {
         fprintf(stderr, "jsonGetString: strlen %d exceeds limit %d\n", (int) strlen(item->valuestring) + 1, size);
         exit(2);
     }
-    strncpy(dst, item->valuestring, size);
+    zstrcpy(dst, item->valuestring, size);
 }
 
 

src/memsafe.c

@@ -0,0 +1,25 @@
+//
+// Created by Michael Henderson on 11/14/23.
+//
+
+#include "memsafe.h"
+
+// zstrcpy safely copies a c-string from src to dst, taking care
+// to avoid overflow and to always terminate the destination.
+// The "size" parameter is the size (in bytes) of the destination.
+// if the source is shorter than the destination, the remainder
+// of the destination will be filled with zeroes.
+int zstrcpy(char *dst, const char *src, size_t size) {
+    int s = 0;  // index into source buffer
+    int d = 0; // index into destination buffer
+    if (size > 0) {
+        for (; d < size; d++) {
+            dst[d] = src[s];
+            if (src[s] != 0) {
+                s++;
+            }
+        }
+        dst[size-1] = 0;
+    }
+    return s;
+}

src/memsafe.h

@@ -0,0 +1,32 @@
+// Far Horizons Game Engine
+// Copyright (c) 2023 Michael D Henderson
+// Copyright (C) 2021 Raven Zachary
+// Copyright (C) 2019 Casey Link, Adam Piggott
+// Copyright (C) 1999 Richard A. Morneau
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+//
+// Created by Michael Henderson on 11/14/23.
+//
+
+#ifndef FAR_HORIZONS_MEMSAFE_H
+#define FAR_HORIZONS_MEMSAFE_H
+
+#include <stddef.h>
+
+// memory safe c-string copy, copied from strlcat
+int zstrcpy(char *dst, const char *src, size_t size);
+
+#endif //FAR_HORIZONS_MEMSAFE_H

src/namplaio.c

@@ -28,6 +28,7 @@
 #include "nampla.h"
 #include "namplaio.h"
 #include "planetio.h"
+#include "memsafe.h"
 
 
 /* load named planet data from file and create empty slots for future use */
@@ -194,7 +195,7 @@ void save_nampla_data(struct nampla_data *namplaData, int numNamplas, FILE *fp)
     for (int i = 0; i < numNamplas; i++) {
         struct nampla_data *nampla = &namplaData[i];
         binary_nampla_data_t *data = &binData[i];
-        strncpy((char *)(data->name), nampla->name, 32);
+        zstrcpy((char *)(data->name), nampla->name, 32);
         data->x = nampla->x;
         data->y = nampla->y;
         data->z = nampla->z;

src/shipio.c

@@ -25,6 +25,7 @@
 #include "ship.h"
 #include "shipio.h"
 #include "item.h"
+#include "memsafe.h"
 
 
 /* load ship data from file and create empty slots for future use */
@@ -95,7 +96,7 @@ void save_ship_data(struct ship_data *shipData, int numShips, FILE *fp) {
     for (int i = 0; i < numShips; i++) {
         struct ship_data *s = &shipData[i];
         binary_ship_data_t *sd = &binData[i];
-        strncpy((char *) (sd->name), s->name, 32);
+        zstrcpy((char *) (sd->name), s->name, 32);
         sd->x = s->x;
         sd->y = s->y;
         sd->z = s->z;

src/version.c

@@ -48,7 +48,7 @@ int versionCommand(int argc, char *argv[]) {
         }
     }
 
-    printf("7.5.7\n");
+    printf("7.5.9\n");
 
     return 2;
 }