fix fd leak on races and cancellation in ctermid

diff --git a/src/unistd/ctermid.c b/src/unistd/ctermid.c
index 21b44ec..c238905 100644 (file)
--- a/src/unistd/ctermid.c
+++ b/src/unistd/ctermid.c
@@ -4,6 +4,7 @@
 #include <fcntl.h>
 #include <unistd.h>
 #include <limits.h>
+#include "syscall.h"
 
 char *ctermid(char *s)
 {
@@ -13,11 +14,11 @@ char *ctermid(char *s)
                if (!s2) s2 = malloc(L_ctermid);
                s = s2;
        }
-       fd = open("/dev/tty", O_WRONLY | O_NOCTTY);
+       fd = open("/dev/tty", O_WRONLY | O_NOCTTY | O_CLOEXEC);
        if (fd < 0)
                return strcpy(s, "");
        if (ttyname_r(fd, s, L_ctermid))
                strcpy(s, "");
-       close(fd);
+       __syscall(SYS_close, fd);
        return s;
 }