Tagging __syslinux_get_serial_info() with __constructor is pretty
useless when the global variables it uses, such as SerialPort, etc,
are assigned *after* the constructor has run. This constructor made
sense when config parsing was done by the core, but parsing is now
performed by ldlinux. We need to explicitly invoke the function to
initialise __syslinux_serial_console_info once we've parsed any config
files.

eprintf.c was introduced in commit 086d698c642f ("ldlinux: Add
eprintf() to print to VGA and serial") because printf() output wasn't
appearing on the serial console. It turns out that the above
__constructor confusion was the real bug.

Signed-off-by: Matt Fleming <matt.fleming@intel.com>

Each module expects the console to start in text mode and will make
explicit calls to openconsole() when another console is required,
e.g. in vesamenu.c32. This mimics the behaviour found in 4.0x.

Signed-off-by: Matt Fleming <matt.fleming@intel.com>

If a type-specifier is used on the command line, e.g.

    .com32 pwd

we should apply the ".c32" filename extension automatically as this
works elsewhere and this behaviour was present in 4.0x.

Signed-off-by: Matt Fleming <matt.fleming@intel.com>

Somewhere along the way the code that prints,

    No DEFAULT or UI configuration directive found!

was broken, and now no longer prints at all. While we're fixing this
it's a good opportunity to rework the logic to be clearer. Now we only
print the message if a config file was found, since these directives
are obviously missing if there is no config file (a warning will be
printed about the lack of config file anyway).

Signed-off-by: Matt Fleming <matt.fleming@intel.com>

The old COM32 loading code would drop the user at a command prompt
once execution returned from the COM32 amodule. We need to replicate
this because most callers of execute() don't expect it to return.

This bug was noticed when loading a COM32 module from
vesamenu.c32. Once execution returned from the COM32 module the
display became garbled because no code exists to reinitialise the
screen for VGA.

Signed-off-by: Matt Fleming <matt.fleming@intel.com>

This adds missing support for booting from a boot sector file such as
.bs, .bss or .0, by re-implementing the old asm bootsec code from
core/bootsect.inc in C.

This has resulted in some external changes. We've had to make StackBuf
a global symbol because we access it directly from execute.c. Also, we
need to move dsinfo.c into MINLIBOBJS because ldlinux now needs to
reference __syslinux_derivative_info.

Signed-off-by: Matt Fleming <matt.fleming@intel.com>

Paulo reported that his default command line wasn't being executed
when the timeout specified in his config file elapsed. This is because
mygetkey() wasn't correctly applying the timeout when waiting for
input.

Furthermore, it seems the ONTIMEOUT parsing was also broken.

Reported-by: Paulo Alcantara <pcacjr@zytor.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>

Make sure we're passing the correct arguments to new_linux_kernel() by
defining a prototype. This also fixes the following warning,

execute.c:108:3: warning: implicit declaration of function ‘new_linux_kernel’

Signed-off-by: Matt Fleming <matt.fleming@intel.com>

... to fix the following build warning,

cli.c: In function ‘edit_cmdline’:
cli.c:411:3: warning: implicit declaration of function ‘print_labels’

Signed-off-by: Matt Fleming <matt.fleming@intel.com>

Include the appropriate headers to fix up the following build
warnings,

ldlinux.c: In function ‘parse_kernel_type’:
ldlinux.c:27:2: warning: implicit declaration of function ‘strncmp’
ldlinux.c: In function ‘load_kernel’:
ldlinux.c:64:2: warning: implicit declaration of function ‘find_label’
ldlinux.c:64:5: warning: assignment makes pointer from integer without a cast

Signed-off-by: Matt Fleming <matt.fleming@intel.com>