Resume now detects if a save has incompatible endianness.

[open-adventure.git] / saveresume.c

diff --git a/saveresume.c b/saveresume.c
index 858498235fae8d5835e4638edf02f334911ec596..c6d0ba0f274d3e73271e92b171a95521caf96694 100644 (file)
--- a/saveresume.c
+++ b/saveresume.c
@@ -18,16 +18,23 @@
 #include "advent.h"
 #include "dungeon.h"
 
+/*
+ * Use this to detect endianness mismatch.  Can't be unchanges by byte-swapping.
+ */
+#define ENDIAN_MAGIC   2317
+
 struct save_t save;
 
 #define IGNORE(r) do{if (r){}}while(0)
 
-int savefile(FILE *fp, int32_t version)
+int savefile(FILE *fp)
 /* Save game to file. No input or output from user. */
 {
-    save.savetime = time(NULL);
-    save.mode = -1;
-    save.version = (version == 0) ? SAVE_VERSION : version;
+    memcpy(&save.magic, ADVENT_MAGIC, sizeof(ADVENT_MAGIC));
+    if (save.version == 0)
+       save.version = SAVE_VERSION;
+    if (save.canary == 0)
+       save.canary = ENDIAN_MAGIC;
 
     save.game = game;
     IGNORE(fwrite(&save, sizeof(struct save_t), 1, fp));
@@ -85,7 +92,7 @@ int suspend(void)
         free(name);
     }
 
-    savefile(fp, SAVE_VERSION);
+    savefile(fp);
     fclose(fp);
     rspeak(RESUME_HELP);
     exit(EXIT_SUCCESS);
@@ -136,7 +143,9 @@ int restore(FILE* fp)
 
     IGNORE(fread(&save, sizeof(struct save_t), 1, fp));
     fclose(fp);
-    if (save.version != SAVE_VERSION) {
+    if (memcmp(save.magic, ADVENT_MAGIC, sizeof(ADVENT_MAGIC)) != 0 || save.canary != ENDIAN_MAGIC)
+       rspeak(BAD_SAVE);
+    else if (save.version != SAVE_VERSION) {
         rspeak(VERSION_SKEW, save.version / 10, MOD(save.version, 10), SAVE_VERSION / 10, MOD(SAVE_VERSION, 10));
     } else if (!is_valid(save.game)) {
        rspeak(SAVE_TAMPERING);