[segment] Add "Requested memory not available" error message
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.
[tables] Incorporate table data type information into table definition
Eliminate the potential for mismatches between table names and the
table entry data type by incorporating the data type into the
definition of the table, rather than specifying it explicitly in each
table accessor method.
[tables] Redefine methods for accessing linker tables
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.
Having a default script containing
#!gpxe
autoboot
can cause problems when entering commands to load and start a kernel
manually; the default script image will still be present when the
kernel is started and so will be treated as an initrd. It is possible
to work around this by typing "imgfree" before any other commands, but
this is counter-intuitive.
Fix by allowing the embedded image list to be empty (in which case we
just call autoboot()), and making this the default.
Reported by alkisg@gmail.com.
[pxe] Obey lists of PXE Boot Servers and associated Discovery Control bits
Various combinations of options 43.6, 43.7 and 43.8 dictate which
servers we send Boot Server Discovery requests to, and which servers
we should accept responses from. Obey these options, and remove the
explicit specification of a single Boot Server from start_pxebs() and
dependent functions.
The DHCP client code now implements only the mechanism of the DHCP and
PXE Boot Server protocols. Boot Server Discovery can be initiated
manually using the "pxebs" command. The menuing code is separated out
into a user-level function on a par with boot_root_path(), and is
entered in preference to a normal filename boot if the DHCP vendor
class is "PXEClient" and the PXE boot menu option exists.
This change allows the time for which shell banners are displayed to
be configured in the config.h file. The ability to access the shell
can also be effectively disabled by setting this timeout to zero.
[image] Fail "imgexec"/"boot" if the image to execute is ambiguous
If there is more than one loaded image, refuse to automatically select
the image to execute. There are at least two possible cases, with
different "correct" answers:
1. User loads image A by mistake, then loads image B and types "boot".
User wants to execute image B.
2. User loads image A, then loads image B (which patches image A), then
types "boot". User wants to execute image A.
If a user actually wants to load multiple images, they must explicitly
specify which image is to be executed.
We can just treat all non-kernel images as initrds, which matches our
behaviour for multiboot kernels. This allows us to eliminate initrd as
an image type, and treat the "initrd" command as just another synonym for
"imgfetch".
This commit implements GDB over UDP. Using UDP is more complex than
serial and has required some restructuring.
The GDB stub is now built using one or both of GDBSERIAL and GDBUDP
config.h options.
To enter the debugger, execute the gPXE shell command:
gdbstub <transport> [<options>...]
Where <transport> is "serial" or "udp". For "udp", the name of a
configured network device is required:
gdbstub udp net0
The GDB stub listens on UDP port 43770 by default.
[iSCSI] Produce meaningful errors on login failure
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.
[HCI] Display "Not an executable image" when appropriate
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.
[Settings] Remove assumption that all settings have DHCP tag values
Allow for settings to be described by something other than a DHCP option
tag if desirable. Currently used only for the MAC address setting.
Separate out fake DHCP packet creation code from dhcp.c to fakedhcp.c.
Remove notion of settings from dhcppkt.c.
Rationalise dhcp.c to use settings API only for final registration of the
DHCP options, rather than using {store,fetch}_setting throughout.
Add the notion of the settings hierarchy, complete with
register/unregister routines.
Rename set->store and get->fetch to avoid naming conflicts with get/put
as used in reference counting.
[Settings] Start revamping the configuration settings API.
Add the concept of an abstract configuration setting, comprising a (DHCP)
tag value and an associated byte sequence.
Add the concept of a settings namespace.
Add functions for extracting string, IPv4 address, and signed and
unsigned integer values from configuration settings (analogous to
dhcp_snprintf(), dhcp_ipv4_option(), etc.).
Update functions for parsing and formatting named/typed options to work
with new settings API.
Update NVO commands and config UI to use new settings API.
show_setting() and related functions now return an "actual length" in the
style of snprintf(). This is to allow consumers to allocate buffers large
enough to hold the formatted setting.
Michael Brown