This commit addresses critical architectural deficiencies in the MINIX kernel build and source structure. The changes are based on a comprehensive technical review and aim to establish a cleaner, more robust foundation for future kernel development.
Key changes include:
1. **Kernel-Specific Type System:**
* I introduced `minix/kernel/include/minix/kernel_types.h`.
* I defined kernel-specific types (e.g., `k_size_t`, `k_pid_t`) and fixed-width integer types (e.g., `k_uint32_t`) to replace userspace types.
2. **Kernel-Space Library (`klib`):**
* I created a new kernel library (`klib`) located in `minix/kernel/klib/`.
* I implemented basic string functions (`kstrlen`, `kstrlcpy`, `kstrcmp`) in `kstring.c`.
* I implemented basic memory functions (`kmemcpy`, `kmemset`, `kmemmove`) in `kmemory.c`.
* I added stub implementations for `kprintf`, `ksprintf`, and `kvprintf` in `kprintf_stub.c`, along with a `KASSERT_PLACEHOLDER` macro.
3. **Purged Userspace Dependencies:**
* I systematically refactored all C and header files within `minix/kernel/` and its subdirectories (`system/`, `arch/i386/`, `arch/earm/`).
* I removed userspace includes (e.g., `<string.h>`, `<stdlib.h>`, `<stdio.h>`, `<assert.h>`, `<sys/types.h>`, `<signal.h>`, `<unistd.h>`).
* I replaced calls to userspace C library functions with their `klib` equivalents or marked them with `FIXME` comments if a direct replacement was not yet available (e.g., `atoi`, `strncmp`).
* I replaced userspace types with their `k_` prefixed kernel versions.
4. **Build System Reconstruction (Meson):**
* I replaced `minix/kernel/meson.build` with a new script designed for a proper kernel build.
* The new build system defines kernel-specific compiler flags, handles architecture detection (i386, x86_64), sets up correct include paths, and builds `klib` and the main kernel executable.
* Assembly file compilation and linkage are noted as TODOs in the Meson script.
**Next Steps & Known Issues:**
The kernel is not expected to build successfully immediately after these changes. A significant number of `FIXME` comments and identified issues need to be addressed in a proper build environment. These include:
* Defining numerous missing constants (error numbers, signal numbers, etc.).
* Providing kernel-safe implementations for macros like `offsetof`.
* Implementing missing `klib` functions (e.g., a real `kprintf`, `kstrncmp`, `kmemcmp`, `katoi`).
* Developing kernel-space signal handling and ELF loading mechanisms.
* Adding rules for compiling and linking assembly source files.
This refactoring establishes the necessary structure to tackle these remaining issues systematically.
