[deflate] Fix literal data length calculation

Fix incorrect calculation used to determine length of data to be
copied within a literal data block, and add a test case to prevent
this bug from going undetected in future.

Signed-off-by: Michael Brown <mcb30@ipxe.org>
[libc] Add abs()

Signed-off-by: Michael Brown <mcb30@ipxe.org>
[uaccess] Add memcmp_user()

Signed-off-by: Michael Brown <mcb30@ipxe.org>
[test] Rewrite pnm_ok() using okx()

Signed-off-by: Michael Brown <mcb30@ipxe.org>
[test] Generalise pnm_ok() to pixbuf_ok()

Signed-off-by: Michael Brown <mcb30@ipxe.org>
[png] Add support for PNG images

Signed-off-by: Michael Brown <mcb30@ipxe.org>
[vesafb] Handle failures from fbcon_init()

Signed-off-by: Michael Brown <mcb30@ipxe.org>
[fbcon] Centre background picture on console

Centre the background picture on the console, to give a more
consistent result when the aspect ratio does not match the requested
width and height.

Once drawn for the first time, nothing should ever overwrite the
margins of the display.  We can therefore eliminate the logic used to
redraw only the margin areas, and use much simpler code to draw the
complete initial background image.

Simplify the redrawing logic further by making the background picture
buffer equal in size to the frame buffer.  In the common case of a
background picture which is designed to fill the screen, this wastes
no extra memory, and the combined code simplifications reduce the size
of fbcon.o by approximately 15%.

Redefine the concept of "margin" to match the intuitive definition
(i.e. the size of the gap, rather than the position of the boundary
line).

Signed-off-by: Michael Brown <mcb30@ipxe.org>
[fbcon] Allow for an arbitrary margin around the text area

Signed-off-by: Michael Brown <mcb30@ipxe.org>
[vesafb] Allow for an arbitrary margin around the text area

Allow for an arbitrary margin to be specified in the console
configuration.  If the actual screen size does not match the requested
screen size, then update any margins specified so that they remain in
the same place relative to the requested screen size.  If margins are
unspecified (i.e. zero), then leave them as zero.

The underlying assumption here is that any specified margins are
likely to describe an area within a background picture, and so should
remain in the same place relative to that background picture.

Signed-off-by: Michael Brown <mcb30@ipxe.org>
[cmdline] Rename "console" command's --bpp option to --depth

Rename the "--bpp" option to "--depth", to free up the single-letter
option "-b" for "--bottom" in preparation for adding margin support.

This does not break backwards compatibility with documented features,
since the "console" command has not yet been documented.

Signed-off-by: Michael Brown <mcb30@ipxe.org>
[cmdline] Add margin options to the "console" command

Signed-off-by: Michael Brown <mcb30@ipxe.org>
[fbcon] Allow ANSI CUP with missing arguments

Signed-off-by: Michael Brown <mcb30@ipxe.org>
[cmdline] Always clear screen after reconfiguring console

Signed-off-by: Michael Brown <mcb30@ipxe.org>
[intel] Add some missing PCI IDs

Tested-by: Philipp Hagen <Philipp.Hagen@she.net>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
[dns] Support DNS search lists

Update the DNS resolver to support DNS search lists (as provided by
DHCP option 119, DHCPv6 option 24, or NDP option 31).

Add validation code to ensure that parsing of DNS packets does not
overrun the input, get stuck in infinite loops, or (worse) write
beyond the end of allocated buffers.

Signed-off-by: Michael Brown <mcb30@ipxe.org>
[dns] Update end-of-name pointer after processing CNAME record

Commit d4c0226 ("[dns] Support DNS search lists") introduced a
regression when handling CNAME records resolving to names longer than
the original name.  The "end of name" offset stored in dns->offset was
not updated to reflect the length of the new name, causing
dns_question() to append the (empty) search suffix at an incorrect
offset within the name buffer, resulting in a mangled DNS name.

In the case of a CNAME record resolving to a name shorter than or
equal in length to the original name, then the mangling would occur in
an unused portion of the name buffer.  In the common case of a name
server returning the A (or AAAA) record along with the CNAME record,
this would cause name resolution to succeed despite the mangling.  (If
the name server did not return the A or AAAA record along with the
CNAME record, then the mangling would be revealed by the subsequent
invalid query packet.)

Reported-by: Nicolas Sylvain <nsylvain@gmail.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
[dhcp] Copy exactly the required length when resizing DHCP options

When resizing DHCP options, iPXE currently calculates the length to be
copied by subtracting the destination pointer from the end of buffer
pointer.  This works and guarantees not to write beyond the end of the
buffer, but may end up reading beyond the end of the buffer.

Fix by calculating the required length exactly.

Signed-off-by: Michael Brown <mcb30@ipxe.org>
[settings] Remove "uristring" setting type

Commit b5f5f73 ("[cmdline] Expand settings within each command-line
token individually") effectively rendered the "uristring" setting type
obsolete, since strings containing whitespace no longer break the
command line parser.  The concept of the "uristring" type is not well
defined, since URI escaping rules depend on which portion of a URI is
being escaped.

Remove the "uristring" type, converting it into an alias for the
"string" setting type so as to avoid breaking existing scripts.

Signed-off-by: Michael Brown <mcb30@ipxe.org>
[params] Use reference counters for form parameter lists

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