diff options
| -rw-r--r-- | sys/kern/tty_inq.c | 11 |
1 files changed, 10 insertions, 1 deletions
diff --git a/sys/kern/tty_inq.c b/sys/kern/tty_inq.c index daf3bde77712..0bf7c2fa5b5e 100644 --- a/sys/kern/tty_inq.c +++ b/sys/kern/tty_inq.c @@ -165,7 +165,8 @@ ttyinq_read_uio(struct ttyinq *ti, struct tty *tp, struct uio *uio, size_t rlen, size_t flen) { - MPASS(rlen <= uio->uio_resid); + /* rlen includes flen, flen bytes will be trimmed from the end. */ + MPASS(rlen - flen <= uio->uio_resid); while (rlen > 0) { int error; @@ -193,6 +194,14 @@ ttyinq_read_uio(struct ttyinq *ti, struct tty *tp, struct uio *uio, rlen -= clen; /* + * Caller shouldn't request that we trim anything if we might be + * reading across blocks. We could handle it, but today we do + * not. + */ + if (flen > 0) + MPASS(rlen == 0); + + /* * We can prevent buffering in some cases: * - We need to read the block until the end. * - We don't need to read the block until the end, but |