diff options
Diffstat (limited to 'hw/char/spapr_vty.c')
| -rw-r--r-- | hw/char/spapr_vty.c | 30 |
1 files changed, 12 insertions, 18 deletions
diff --git a/hw/char/spapr_vty.c b/hw/char/spapr_vty.c index 7f860fcce7..087c93e4fa 100644 --- a/hw/char/spapr_vty.c +++ b/hw/char/spapr_vty.c @@ -59,25 +59,19 @@ static int vty_getchars(SpaprVioDevice *sdev, uint8_t *buf, int max) int n = 0; while ((n < max) && (dev->out != dev->in)) { - buf[n++] = dev->buf[dev->out++ % VTERM_BUFSIZE]; - - /* PowerVM's vty implementation has a bug where it inserts a - * \0 after every \r going to the guest. Existing guests have - * a workaround for this which removes every \0 immediately - * following a \r, so here we make ourselves bug-for-bug - * compatible, so that the guest won't drop a real \0-after-\r - * that happens to occur in a binary stream. */ - if (buf[n - 1] == '\r') { - if (n < max) { - buf[n++] = '\0'; - } else { - /* No room for the extra \0, roll back and try again - * next time */ - dev->out--; - n--; - break; - } + /* + * Long ago, PowerVM's vty implementation had a bug where it + * inserted a \0 after every \r going to the guest. Existing + * guests have a workaround for this which removes every \0 + * immediately following a \r. To avoid triggering this + * workaround, we stop before inserting a \0 if the preceding + * character in the output buffer is a \r. + */ + if (n > 0 && (buf[n - 1] == '\r') && + (dev->buf[dev->out % VTERM_BUFSIZE] == '\0')) { + break; } + buf[n++] = dev->buf[dev->out++ % VTERM_BUFSIZE]; } qemu_chr_fe_accept_input(&dev->chardev); |