This was inspired by the detection of 2 instances of the warning:
warning: 'strncpy' specified bound 16 equals destination size
[-Wstringop-truncation]
The current code is already safe with regards to overflows, because
fixed-length string functions are used in the call tree. However, when
given a name 16 chars or larger, the current compare in llext_by_name()
will not work as expected because the stored extension name is truncated
to a max of 15.
Define a global LLEXT_MAX_NAME_LEN constant to simplify all this logic
and also implement name checks in the shell before calling llext_load().
Finally, using strlen() instead of strnlen() gets the real length of the
hex string passed as a parameter, which is important for the next safety
check.
Signed-off-by: Luca Burelli <l.burelli@arduino.cc>
Make sure the buffer used to load the hex file is aligned to a sensible
value; at least word size is assumed by the LLEXT APIs.
Signed-off-by: Luca Burelli <l.burelli@arduino.cc>
The shell command 'llext list_symbols' currently iterates over the
'sym_tab' table. This is valid only inside 'llext_load' and is freed
before returning, so it will always be empty in shell context.
Fix it to display 'exp_tab', which is the one used at runtime by LLEXT
to provide symbols to the main application.
Signed-off-by: Luca Burelli <l.burelli@arduino.cc>
This patch extends LLEXT shell commands with support for loading
LLEXT from a filesystem. Use of the command requires absolute path
to the llext file.
Example use:
`llext load_llext hello_world /lfs/hello_world.llext`
Signed-off-by: Adam Wojasinski <awojasinski@baylibre.com>
This patch changes the error codes returned by the ELF subsystem to be
more consistent with the standard error descriptions. In particular:
- issues with the ELF file are now reported as -ENOEXEC;
- valid but unsupported edge cases are reported as -ENOTSUP;
- failures in searching for an entry are reported as -ENOENT.
Signed-off-by: Luca Burelli <l.burelli@arduino.cc>
Dynamic command handlers should be fully initialized to avoid undefined
behavior. Also, fix the number of arguments required by each command,
since llext_call_fn requires both the llext and the name of the function
to be called.
Signed-off-by: Luca Burelli <l.burelli@arduino.cc>
The llext list should be internal to llext.c, remove its scanning
from shell.c, export a function for that instead.
Signed-off-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
Extend the llext_load() / llext_unload() API to let it be called
repeatedly for the same extension to increment or decrement its
reference counter respectively. We use a mutex to protect the counter
and make both llext_load() and llext_unload() return the use-count to
let the caller identify when the first loading and the last unloading
took place.
Signed-off-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
Some applications can decide to link their loadable objects for
exactly the same addresses, where they will be loaded. In those cases
local relocations aren't needed any more and can in fact break the
object if applied while the object is in a temporary storage. Add a
parameter to skip such local relocations.
Signed-off-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
Remove unnecessary newline characters from shell_print, it already adds
them. Align the table pipe characters better in the list of modules.
Signed-off-by: Tom Burdick <thomas.burdick@intel.com>
The maximum size of an extension accept by the shell
was previously a define and is now made configurable through Kconfig.
Signed-off-by: Kai Meinhard <meinhard@gessler.de>
Adds the linkable loadable extensions (llext) subsystem which provides
functionality for reading, parsing, and linking ELF encoded executable
code into a managed extension to the running elf base image.
A loader interface, and default buffer loader implementation,
make available to the llext subsystem the elf data. A simple management
API provide the ability to load and unload extensions as needed. A shell
interface for extension loading and unloading makes it easy to try.
Adds initial support for armv7 thumb built elfs with very specific
compiler flags.
Signed-off-by: Tom Burdick <thomas.burdick@intel.com>
Co-authored-by: Chen Peng1 <peng1.chen@intel.com>
Co-authored-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
