Relicense files for which I am the sole author (as identified by
util/relicense.pl).

Signed-off-by: Michael Brown <mcb30@ipxe.org>

iPXE will detect timeout failures in several situations: network
link-up, DHCP, TCP connection attempts, unacknowledged TCP data, etc.
This does not cover all possible circumstances.  For example, if a
connection to a web server is successfully established and the web
server acknowledges the HTTP request but never sends any data in
response, then no timeout will be triggered.  There is no timeout
defined within the HTTP specifications, and the underlying TCP
connection will not generate a timeout since it has no way to know
that the HTTP layer is expecting to receive data from the server.

Add a "--timeout" parameter to "imgfetch", "chain", etc.  If no
progress is made (i.e. no data is downloaded) within the timeout
period, then the download will be aborted.

Signed-off-by: Michael Brown <mcb30@ipxe.org>

Remove the name, cmdline, and action parameters from imgdownload() and
imgdownload_string().  These functions now simply download and return
an image.

Add the function imgacquire(), which will interpret a "name or URI
string" parameter and return either an existing image or a newly
downloaded image.

Use imgacquire() to merge similar image-management commands that
currently differ only by whether they take the name of an existing
image or the URI of a new image to download.  For example, "chain" and
"imgexec" can now be merged.

Extend imgstat and imgfree commands to take an optional list of
images.

Remove the arbitrary restriction on the length of image names.

Signed-off-by: Michael Brown <mcb30@ipxe.org>

All users of imgdownload() require registration of the image, so make
registration an integral part of imgdownload() itself and simplify the
"action" parameter to be one of image_select(), image_exec() et al.

Signed-off-by: Michael Brown <mcb30@ipxe.org>

Allow imgdownload() to be called without first having to allocate (and
so keep track of) an image.

Signed-off-by: Michael Brown <mcb30@ipxe.org>

These functions are used only as the "action" parameters to
imgdownload() or imgfetch(), and so belong in imgmgmt.c rather than
image.c

Signed-off-by: Michael Brown <mcb30@ipxe.org>

Refactor the {load,exec} image operations as {probe,exec}.  This makes
the probe mechanism cleaner, eliminates some forward declarations,
avoids holding magic state in image->priv, eliminates the possibility
of screwing up between the "load" and "exec" stages, and makes the
documentation simpler since the concept of "loading" (as distinct from
"executing") no longer needs to be explained.

Signed-off-by: Michael Brown <mcb30@ipxe.org>

Allow the monojob controlling the download to complete before calling
register_image() and friends.  This allows the trailing "ok" from
monojob.c to be printed before the image starts executing (and
possibly printing output of its own).

Signed-off-by: Michael Brown <mcb30@ipxe.org>

For performing installations direct to a SAN target, it can be very
useful to hook a SAN disk and then proceed to perform a filename boot.
For example, the user may wish to hook the (empty) SAN installation
disk and then boot into the OS installer via TFTP.  This provides an
alternative mechanism to using "keep-san" and relying on the BIOS to
fall through to boot from the installation media, which is unreliable
on many BIOSes.

When a root-path is specified in addition to a boot filename, attempt
to hook the root-path as a SAN disk before booting from the specified
filename.  Since the root-path may be used for non-SAN purposes
(e.g. an NFS root mount point), ignore the root-path if it contains a
URI scheme that we do not support.

Originally-implemented-by: Jarrod Johnson <jarrod.b.johnson@gmail.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>

Add FILE_LICENCE declarations to almost all files that make up the
various standard builds of gPXE.

Some shuffling around of the image management code; this needs tidying up.

"kernel".