_open: fix static corruptor

We can block in a tty open, which if another open then occurs leaves
the staticfast "ino" corrupted. Save it in a temporary variable so that
for we still get almost all the benefit of staticfast here.

diff --git a/Kernel/syscall_fs2.c b/Kernel/syscall_fs2.c
index 2475446..3342d5f 100644 (file)
--- a/Kernel/syscall_fs2.c
+++ b/Kernel/syscall_fs2.c
@@ -409,6 +409,7 @@ int16_t _open(void)
        int8_t uindex;
        int8_t oftindex;
        staticfast inoptr ino;
+       inoptr itmp;
        int16_t perm;
        staticfast inoptr parent;
        char fname[FILENAME_LEN + 1];
@@ -471,11 +472,16 @@ int16_t _open(void)
                udata.u_error = EISDIR;
                goto cantopen;
        }
+       itmp = ino;
+       /* d_open may block and thus ino may become invalid as may
+          parent (but we don't need it again) */
        if (isdevice(ino)
            && d_open((int) ino->c_node.i_addr[0], flag) != 0) {
                udata.u_error = ENXIO;
                goto cantopen;
        }
+       /* get the static pointer back */
+       ino = itmp;
        if (trunc && getmode(ino) == F_REG) {
                f_trunc(ino);
                for (j = 0; j < OFTSIZE; ++j)
@@ -499,6 +505,8 @@ int16_t _open(void)
            && !(flag & O_NDELAY))
                psleep(ino);
 
+        /* From the moment of the psleep ino is invalid */
+
        return (uindex);
       idrop:
        i_deref(ino);