7.8 KiB
libkernaux
)
Auxiliary library for kernel development.
Table of contents
API
We use semantic versioning for stable APIs. Stable APIs can only change when major version number is increased (or minor while major is zero). Work-in-progress APIs can change at any time.
- Runtime environment
- Architecture-specific code (work in progress)
- Assertions (stable since 0.1.0, non-breaking since 0.2.0)
- Stack trace (planned)
- Device drivers (for debugging only)
- Serial console (work in progress)
- Framebuffer (planned)
- USB (planned)
- Algorithms
- Simple command line parser (stable since 0.2.0)
- Page Frame Allocator (work in progress)
- Data formats
- ELF (work in progress)
- Master Boot Record (work in progress)
- Multiboot 2 (GRUB 2) (work in progress)
- Stivale 2 (Limine) (planned)
- Utilities
- Measurement units utils (work in progress)
- Usual functions
- libc replacement (stable since 0.1.0)
- itoa/ftoa replacement (stable since 0.1.0)
- printf replacement (stable since 0.1.0)
- Code from https://github.com/mpaland/printf. Thank you!
- printf
- vprintf
- snprintf
- vsnprintf
Configuration
Because this library has no external dependencies, we use autoconf features to control behavior of the library, and packages to choose it's components. Configuration options also follow the semantic versioning scheme and are split into stable and work-in-progress ones. Here we cover only stable options.
Non-default options
Packages
--with-libc- provides the replacement for some standard C functions. Useful in freestanding environment, where no libc is present. You can also separately include or exclude components:--with[out]-libc-atoi--with[out]-libc-isdigit--with[out]-libc-isspace--with[out]-libc-memset--with[out]-libc-strcpy--with[out]-libc-strlen--with[out]-libc-strnlen
Default options
Features
--enable-float(disable with--disable-float) - floating-point arithmetic--enable-pic(disable with--disable-pic) - generate position-independent code--enable-werror(disable with--disable-werror) - fail on warning (CFLAGS+='-Werror')
Packages
All packages all included by default. To exclude all packages except those
explicitly included, use --without-all.
--with[out]-cmdline- command line parser--with[out]-ntoa- itoa/ftoa--with[out]-printf- printf
Tips
Installation
./autogen.sh
./configure
make
sudo make install
This is just a usual library. You can use most of it's APIs in hosted environment.
Development
./autogen.sh
./configure --enable-tests-all
make
You can test with make check.
Some tests require Python 3 with YAML and Jinja2. Disable them with
--disable-tests-python.
Cross
Create configuration script with ./autogen.sh.
Let's assume that your target triplet is i386-elf. Configure with
cross-compiler in $PATH to make
without it in $PATH:
./configure \
--host='i386-elf' \
--disable-pic \
--with-libc \
AR="$(which i386-elf-ar)" \
CC="$(which i386-elf-gcc)" \
RANLIB="$(which i386-elf-ranlib)" \
CFLAGS='-ffreestanding -nostdlib -fno-stack-protector'
You can see the following messages. It's a bug in autoconf, just ignore it.
checking for _Bool... no
checking stdarg.h usability... no
checking stdarg.h presence... yes
configure: WARNING: stdarg.h: present but cannot be compiled
configure: WARNING: stdarg.h: check for missing prerequisite headers?
configure: WARNING: stdarg.h: see the Autoconf documentation
configure: WARNING: stdarg.h: section "Present But Cannot Be Compiled"
configure: WARNING: stdarg.h: proceeding with the compiler's result
configure: WARNING: ## ---------------------------------------------------------- ##
configure: WARNING: ## Report this to https://github.com/tailix/libkernaux/issues ##
configure: WARNING: ## ---------------------------------------------------------- ##
checking for stdarg.h... no
checking stddef.h usability... no
checking stddef.h presence... yes
configure: WARNING: stddef.h: present but cannot be compiled
configure: WARNING: stddef.h: check for missing prerequisite headers?
configure: WARNING: stddef.h: see the Autoconf documentation
configure: WARNING: stddef.h: section "Present But Cannot Be Compiled"
configure: WARNING: stddef.h: proceeding with the compiler's result
configure: WARNING: ## ---------------------------------------------------------- ##
configure: WARNING: ## Report this to https://github.com/tailix/libkernaux/issues ##
configure: WARNING: ## ---------------------------------------------------------- ##
checking for stddef.h... no
To install into specific directory use full path: DESTDIR="$(pwd)/dest" make install instead of DESTDIR=dest make install.
Check if compilation targets i386: objdump -d src/asm/i386.o. It should output
something like this:
src/asm/i386.o: file format elf32-i386
Disassembly of section .text:
00000000 <kernaux_asm_i386_read_cr0>:
0: 0f 20 c0 mov %cr0,%eax
3: c3 ret
00000004 <kernaux_asm_i386_read_cr4>:
4: 0f 20 e0 mov %cr4,%eax
7: c3 ret
00000008 <kernaux_asm_i386_write_cr0>:
8: 8b 44 24 04 mov 0x4(%esp),%eax
c: 0f 22 c0 mov %eax,%cr0
f: c3 ret
00000010 <kernaux_asm_i386_write_cr3>:
10: 8b 44 24 04 mov 0x4(%esp),%eax
14: 0f 22 d8 mov %eax,%cr3
17: c3 ret
00000018 <kernaux_asm_i386_write_cr4>:
18: 8b 44 24 04 mov 0x4(%esp),%eax
1c: 0f 22 e0 mov %eax,%cr4
1f: c3 ret
Architectures
Architectures should be properly identified. We use the following scheme, but it may change in future:
x86i386x86_64
riscvriscv64
arm- we need more info, now similar to Debianarmelarmhfarm64