Lock game an position file during writing

[xboard.git] / backend.c

diff --git a/backend.c b/backend.c
index f6e75c4..9ecc707 100644 (file)
--- a/backend.c
+++ b/backend.c
@@ -270,6 +270,7 @@ char chatPartner[MAX_CHAT][MSG_SIZ]; /* [HGM] chat: list of chatting partners */
 extern int chatCount;
 int chattingPartner;
 char marker[BOARD_RANKS][BOARD_FILES]; /* [HGM] marks for target squares */
+char lastMsg[MSG_SIZ];
 ChessSquare pieceSweep = EmptySquare;
 ChessSquare promoSweep = EmptySquare, defaultPromoChoice;
 int promoDefaultAltered;
@@ -10991,6 +10992,7 @@ SaveGameToFile(filename, append)
 {
     FILE *f;
     char buf[MSG_SIZ];
+    int result;
 
     if (strcmp(filename, "-") == 0) {
        return SaveGame(stdout, 0, NULL);
@@ -11001,7 +11003,14 @@ SaveGameToFile(filename, append)
            DisplayError(buf, errno);
            return FALSE;
        } else {
-           return SaveGame(f, 0, NULL);
+           safeStrCpy(buf, lastMsg, MSG_SIZ);
+           DisplayMessage(_("Waiting for access to save file"), "");
+           flock(fileno(f), LOCK_EX); // [HGM] lock: lock file while we are writing
+           DisplayMessage(_("Saving game"), "");
+           if(lseek(fileno(f), 0, SEEK_END) == -1) DisplayError("Bad Seek", errno);     // better safe than sorry...
+           result = SaveGame(f, 0, NULL);
+           DisplayMessage(buf, "");
+           return result;
        }
     }
 }
@@ -11363,7 +11372,13 @@ SavePositionToFile(filename)
            DisplayError(buf, errno);
            return FALSE;
        } else {
+           safeStrCpy(buf, lastMsg, MSG_SIZ);
+           DisplayMessage(_("Waiting for access to save file"), "");
+           flock(fileno(f), LOCK_EX); // [HGM] lock
+           DisplayMessage(_("Saving position"), "");
+           lseek(fileno(f), 0, SEEK_END);     // better safe than sorry...
            SavePosition(f, 0, NULL);
+           DisplayMessage(buf, "");
            return TRUE;
        }
     }