coreboot-kgpe-d16/payloads/libpayload
Jacob Garber 768db4f5ca libpayload/libc: Correct strlcat return value
The documented return value for strlcat is horribly wrong, as is the
return value itself. It should not return the number of appended bytes,
but rather the length of the concatenated string. From the man page:

    The strlcpy() and strlcat() functions return the total length of the
    string they tried to create. For strlcpy() that means the length of
    src. For strlcat() that means the initial length of dst plus the
    length of src. While this may seem somewhat confusing, it was done
    to make truncation detection simple.

This change is more likely to fix existing code than break it, since
anyone who uses the return value of strlcat will almost certainly rely
on the standard behaviour rather than investigate coreboot's source code
to see that we have a quirky version.

Change-Id: I4421305af85bce88d12d6fdc2eea6807ccdcf449
Signed-off-by: Jacob Garber <jgarber1@ualberta.ca>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/33787
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Julius Werner <jwerner@chromium.org>
2019-07-23 09:09:32 +00:00
..
arch libpayload: Align main() data types 2019-04-05 22:37:19 +00:00
bin libpayload: Move base address, stack and heap size to Kconfig 2016-03-15 20:53:38 +01:00
configs payloads/libpayload: Update a Makefile for sample libpayload 2019-06-21 09:16:36 +00:00
crypto payloads: Replace all IS_ENABLED(CONFIG_XXX) with CONFIG(XXX) 2019-03-07 17:15:30 +00:00
curses libpayload: Enable -Wimplicit-fallthrough 2019-07-21 17:17:42 +00:00
drivers libpayload/usb: fix DWC2 driver 2019-07-09 13:05:53 +00:00
gdb libpayload: gdb: Factor out gdb_handle_reentrant_exception() from arm32 2018-10-12 20:17:40 +00:00
include libpayload/usb: Increase USB request timeout to 5 s 2019-07-02 17:42:18 +00:00
libc libpayload/libc: Correct strlcat return value 2019-07-23 09:09:32 +00:00
libcbfs payloads: Replace all IS_ENABLED(CONFIG_XXX) with CONFIG(XXX) 2019-03-07 17:15:30 +00:00
liblz4 Rename __attribute__((packed)) --> __packed 2017-07-13 19:45:59 +00:00
liblzma libpayload: lzma: Allocate scratchpad on the heap 2016-08-08 19:02:07 +02:00
libpci libpayload: Add pci_free_dev() and some boilerplate 2017-12-07 21:51:24 +00:00
sample payloads/libpayload: Update a Makefile for sample libpayload 2019-06-21 09:16:36 +00:00
tests Remove empty lines at end of file 2015-06-08 00:55:07 +02:00
Doxyfile payloads: Remove/fix trailing whitespace 2018-09-04 12:38:40 +00:00
Kconfig libpayload: Add UART for qcs405 2019-06-04 14:14:58 +00:00
LICENSES libpayload: Add LZ4 decompression algorithm 2015-07-09 00:10:16 +02:00
LICENSE_GPL
Makefile libpayload: Make libpayload compile using gnu11 2018-07-16 07:44:03 +00:00
Makefile.inc libpayload: Enable -Wimplicit-fallthrough 2019-07-21 17:17:42 +00:00
README payloads/libpayload: Update a Makefile for sample libpayload 2019-06-21 09:16:36 +00:00

README

-------------------------------------------------------------------------------
libpayload README
-------------------------------------------------------------------------------

libpayload is a minimal library to support standalone payloads
that can be booted with firmware like coreboot. It handles the setup
code, and provides common C library symbols such as malloc() and printf().

Note: This is _not_ a standard library for use with an operating system,
rather it's only useful for coreboot payload development!
See https://www.coreboot.org for details on coreboot.


Installation
------------

 $ git clone https://review.coreboot.org/coreboot.git

 $ cd coreboot/payloads/libpayload

 $ make menuconfig

 $ make

 $ make install (optional, will install into ./install per default)

On x86 systems, libpayload will always be 32-bit even if your host OS runs
in 64-bit, so you might have to install the 32-bit libgcc version.
On Debian systems you'd do 'apt-get install gcc-multilib' for example.

Run 'make distclean' before switching boards. This command will remove
your current .config file, so you need 'make menuconfig' again or
'make defconfig' in order to set up configuration. Default configuration
is based on 'configs/defconfig'. See the configs/ directory for examples
of configuration.


Usage
-----

Here's an example of a very simple payload (hello.c) and how to build it:

 #include <libpayload.h>

 int main(void)
 {
     printf("Hello, world!\n");
     return 0;
 }

Building the payload using the 'lpgcc' compiler wrapper:

 $ lpgcc -o hello.elf hello.c

Please see the sample/ directory for details.


Website and Mailing List
------------------------

The main website is https://www.coreboot.org/Libpayload.

For additional information, patches, and discussions, please join the
coreboot mailing list at https://www.coreboot.org/Mailinglist, where most
libpayload developers are subscribed.


Copyright and License
---------------------

See LICENSES.