Add support for dealing with string operands, including reading a string
from memory into an environment variable and concatenating two strings.

Signed-off-by: Simon Glass <sjg@chromium.org>
Acked-by: Marek Behún <marek.behun@nic.cz>

At present a ulong is used to hold operand values. This means that
strings cannot be used. While most operations are not useful for strings,
concatenation is. As a starting point to supporting strings, convert the
code to use a struct instead of a ulong for operands.

Signed-off-by: Simon Glass <sjg@chromium.org>

At present when more than one substitution is made this function
overwrites its buffers. Fix this bug and update the tests now that they
can pass.

Also update the debug code to show all substrings, since at present it
omits the final one.

Fixes: 855f18ea0e6 ("setexpr: add regex substring matching and substitution")
Signed-off-by: Simon Glass <sjg@chromium.org>

At present the 'nlen' variable increases with each loop. If the previous
loop had back references, then subsequent loops without back references
use the wrong value of nlen. The value is larger, meaning that the string
terminator from nbuf is copied along to the main buffer, thus terminating
the string prematurely.

This leads to the final result being truncated, e.g. missing the last
(unmatched) part of the string. So "match match tail" become
"replaced replaced" instead of "replaced replaced tail".

Fix this by resetting nlen to the correct value each time around the lop.

Fixes: 855f18ea0e6 ("setexpr: add regex substring matching and substitution")
Signed-off-by: Simon Glass <sjg@chromium.org>

Add tests to check for buffer overflow using simple replacement as well
as back references. At present these don't fully pass.

Signed-off-by: Simon Glass <sjg@chromium.org>

At present this function always allocates a large amount of stack, and
selects its own size for buffers. This makes it hard to test the code
for buffer overflow.

Separate out the inner logic of the substitution so that tests can call
this directly. This will allow checking that the algorithm does not
overflow the buffer.

Fix up one of the error lines at the same time, since it should be
printing nbuf_size, not data_size.

Signed-off-by: Simon Glass <sjg@chromium.org>

At present this function assumes that a size of 4 refers to a ulong. This
is true on 32-bit machines but not commonly on 64-bit machines.

This means that the 'l' specify does not work correctly with setexpr.

Add an explicit case for 32-bit values so that 64-bit machines can still
use the 'l' specifier. On 32-bit machines, 64-bit is still not supported.

This corrects the operation of the default size (which is 4 for setexpr),
so update the tests accordingly.

The original code for reading from memory was included in 47ab5ad1457
("cmd_setexpr: allow memory addresses in expressions") but I am not adding
a Fixes: tag since that code was not written with 64-bit machines in mind.

Signed-off-by: Simon Glass <sjg@chromium.org>

Move this header out of the common header.

Signed-off-by: Simon Glass <sjg@chromium.org>

We should not use typedefs in U-Boot. They cannot be used as forward
declarations which means that header files must include the full header to
access them.

Drop the typedef and rename the struct to remove the _s suffix which is
now not useful.

This requires quite a few header-file additions.

Signed-off-by: Simon Glass <sjg@chromium.org>

Move env_set_hex() over to the new header file along with env_set_addr()
which uses it.

Signed-off-by: Simon Glass <sjg@chromium.org>
Acked-by: Joe Hershberger <joe.hershberger@ni.com>