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author | June McEnroe <june@causal.agency> | 2021-06-11 21:09:46 -0400 |
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committer | June McEnroe <june@causal.agency> | 2021-06-11 21:15:34 -0400 |
commit | f6e8078c4698d371359ff8827a017535e421496c (patch) | |
tree | 2dbe42ed831a8bcbc1a337fe75f2a5e4f764cd42 | |
parent | Open save file with "a+" (diff) | |
download | catgirl-f6e8078c4698d371359ff8827a017535e421496c.tar.gz catgirl-f6e8078c4698d371359ff8827a017535e421496c.zip |
Exclusively lock save file
Prevents two instances of catgirl from using the same save file and clobbering each other's data.
-rw-r--r-- | ui.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/ui.c b/ui.c index 22b098e..2beba88 100644 --- a/ui.c +++ b/ui.c @@ -32,6 +32,7 @@ #include <curses.h> #include <err.h> #include <errno.h> +#include <fcntl.h> #include <limits.h> #include <signal.h> #include <stdarg.h> @@ -1183,6 +1184,11 @@ void uiLoad(const char *name) { if (!saveFile) exit(EX_CANTCREAT); rewind(saveFile); + int error = flock(fileno(saveFile), LOCK_EX | LOCK_NB); + if (error && errno == EWOULDBLOCK) { + errx(EX_CANTCREAT, "%s: save file in use", name); + } + time_t signature; fread(&signature, sizeof(signature), 1, saveFile); if (ferror(saveFile)) err(EX_IOERR, "fread"); |