libslirp introduced a new API for constructing polling lists, to
accommodate Windows platforms where a handle descriptor may be too
large for an int.
Older versions of libslirp do not have the new API calls, and the
older API calls were immediately marked as deprecated, with no
overlap. We would therefore need to use #ifdef and always have some
code that is deliberately not compiled, depending on the version of
libslirp that we find on the user's system. This is highly
undesirable.
Work around this by disabling the deprecation warning (which is what
libslirp itself does for the portions of its code that necessarily
touch the deprecated functions).
Signed-off-by: Michael Brown <mcb30@ipxe.org>
The iPXE build system is constructed for a standalone codebase with no
external dependencies, and does not have any equivalent of the
standard userspace ./configure script. We currently check for the
ability to include slirp/libslirp.h and conditionalise portions of
linux_api.c on its presence. The actual slirp driver code is built
unconditionally, as with all iPXE drivers.
This currently leads to a silent runtime failure if attempting to use
slirp.linux built on a system that was missing slirp/libslirp.h.
Convert this to a link-time failure by deliberately omitting the
relevant symbols from linux_api.c when slirp/libslirp.h is not
present. This allows other builds (e.g. tap.linux or tests.linux) to
succeed: the link-time failure will occur only if the slirp driver is
included within the build target.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
The statx() system call has a clean header file and a consistent
layout, but was unfortunately added only in kernel 4.11.
Using stat() or fstat() directly is extremely messy since glibc does
not necessarily use the kernel native data structures. However, as
the only current use case is to obtain the length of an open file, we
can merely provide a wrapper that does precisely this.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Versions of gcc prior to 9.1 do not support the single-argument form
of static_assert(). Fix by unconditionally defining a compatibility
macro for the single file that uses this.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Add a driver using libslirp to provide a virtual network interface
without requiring root permissions on the host. This simplifies the
process of running iPXE as a Linux userspace application with network
access. For example:
make bin-x86_64-linux/slirp.linux
./bin-x86_64-linux/slirp.linux --net slirp
libslirp will provide a built-in emulated DHCP server and NAT router.
Settings such as the boot filename may be controlled via command-line
options. For example:
./bin-x86_64-linux/slirp.linux \
--net slirp,filename=http://192.168.0.1/boot.ipxe
Signed-off-by: Michael Brown <mcb30@ipxe.org>
When building as a Linux userspace application, iPXE currently
implements its own system calls to the host kernel rather than relying
on the host's C library. The output binary is statically linked and
has no external dependencies.
This matches the general philosophy of other platforms on which iPXE
runs, since there are no external libraries available on either BIOS
or UEFI bare metal. However, it would be useful for the Linux
userspace application to be able to link against host libraries such
as libslirp.
Modify the build process to perform a two-stage link: first picking
out the requested objects in the usual way from blib.a but with
relocations left present, then linking again with a helper object to
create a standard hosted application. The helper object provides the
standard main() entry point and wrappers for the Linux system calls
required by the iPXE Linux drivers and interface code.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
