Users tend to gloss over cryptic-looking error messages such as

  "Boot failed: Exec format error (Error 0x2e852001)"

In particular, users tend not to report the error number, which is the
single most useful piece of diagnostic information in an iPXE error
message.  Try replacing the "Error 0x2e852001" portion with a URL,
giving

  "Boot failed: Exec format error (http://ipxe.org/2e852001)"

in the hope that users will, upon seeing something that is
recognisably a URL, try viewing it in a web browser.  Such users will
be greeted by a web page containing a more detailed description of the
error (automatically generated from the einfo text), including links
to each line of code that might generate the error, and a section for
additional user-contributed notes.  At the time of writing, a user who
visits http://ipxe.org/2e852001 would see a note saying

  "This error usually indicates that the SAN disk is empty, and does
   not yet contain a bootable operating system."

which may be more useful than "Exec format error (Error 0x2e852001)".

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

Add preprocessor magic to the error definitions to enable every error
usage to be tracked.

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

Access to the gpxe.org and etherboot.org domains and associated
resources has been revoked by the registrant of the domain.  Work
around this problem by renaming project from gPXE to iPXE, and
updating URLs to match.

Also update README, LOG and COPYRIGHTS to remove obsolete information.

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

Expand the NETDEV_LINK_UP bit into a link_rc status code field,
allowing specific reasons for link failure to be reported via
"ifstat".

Originally-authored-by: Joshua Oreman <oremanj@rwcr.net>

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

prep_segment() can sometimes fail because an image requests memory
that is already in use by gPXE.  This will happen if
e.g. undionly.kpxe is used to boot memtest86; the memtest86 image is
an old-format kernel that needs to be loaded at 9000:0000, but this
area of memory may well already be in use by the underlying PXE stack.

Add a human-friendly error message, so that the cause is more
immediately visible.

Intel's C compiler (icc) chokes on the zero-length arrays that we
currently use as part of the mechanism for accessing linker table
entries.  Abstract away the zero-length arrays, to make a port to icc
easier.

Introduce macros such as for_each_table_entry() to simplify the common
case of iterating over all entries in a linker table.

Represent table names as #defined string constants rather than
unquoted literals; this avoids visual confusion between table names
and C variable or type names, and also allows us to force a
compilation error in the event of incorrect table names.

Return the most appropriate of EACCES, EPERM, ENODEV, ENOTSUP, EIO or
EINVAL depending on the exact error returned by the target, rather than
just always returning EPERM.

Also, ensure that error strings exist for these errors.

PXE is a catch-all image format with no signature checks.  If an
unsupported image file is loaded, it will be treated as a PXE image.  In
most cases, the image will be too large to be loaded as a PXE image (which
has to fit in base memory), so the error returned to the user will be that
the segment could not fit within the memory region.

Add an explicit check to pxe_image.c to reject images larger than base
memory with ENOEXEC.

Add ENOEXEC to the error string table.

tcpip_tx().  This avoids the irritating wait when you accidentally type
"kernel pxelinux.0" before bringing up the network interface.

Add ENETUNREACH to strerror()'s list.

strerror(rc) in their closed() methods without producing "Error
0x0000" when the connection is closed normally.

names.

Add "dev" pointer in struct net_device to tie network interfaces back to a
hardware device.

Force natural alignment of data types in __table() macros.  This seems to
prevent gcc from taking the unilateral decision to occasionally increase
their alignment (which screws up the table packing).

"Permission denied" as an error text to strerror().

Kill errortab array; it can screw up alignment.

us to return proper PXE status codes, while simultaneously allowing for
more consistent error reporting (complete with verbose error messages as a
build-time option).