[Qemu-devel] Incorrect handling of interrupted syscalls

[Florian Zumbiehl]

Hi,

when trying to write a driver that provides a ppdev-compatible API
but forwards the data written to the parport to a userspace program,
I noticed that Qemu (0.8.2-4etch1 from Debian Etch, but the changelog
of 0.9.0 doesn't look like it has been fixed there) doesn't handle
interrupted system calls properly, at least as far as the parport
emulation is concerned. When the involved ioctl()s get interrupted
by a SIGALRM, they don't get restarted, so some port writes get
lost.

Florian