Add newlib support

.gitmodules

@@ -0,0 +1,3 @@
+[submodule "lib/newlib-cygwin"]
+	path = lib/newlib-cygwin
+	url = https://sourceware.org/git/newlib-cygwin.git

Makefile

@@ -1,6 +1,6 @@
-.PHONY: all kernel clean format user initramfs
+.PHONY: all lib kernel clean format user initramfs
 
-all: kernel user initramfs
+all: lib kernel user initramfs
 
 kernel:
 	@echo "Building Kernel..."
@@ -12,12 +12,17 @@ user_bin:
 	@echo "Building user binaries..."
 	$(MAKE) -C user bin
 
+lib:
+	$(MAKE) -C lib
+
 initramfs: user
 	@( cd build/initramfs && find . -print | cpio -o -H newc -v ) > build/initramfs.cpio
 
 format:
 	@echo "Formatting Kernel..."
 	$(MAKE) -C kernel format
+	@echo "Formatting Lib..."
+	$(MAKE) -C lib format
 	@echo "Formatting User..."
 	$(MAKE) -C user format
 

build.sh

@@ -1,12 +1,7 @@
 #!/bin/sh
 
-export CC=x86_64-elf-gcc
-export CXX=x86_64-elf-g++
-export LD=x86_64-elf-ld
-export AS=x86_64-elf-as
-export AR=x86_64-elf-ar
-
 NPROC=$(getconf _NPROCESSORS_ONLN)
+ROOTDIR=$(pwd)
 
 export MAKE=make
 if [ "$(uname)" = "Darwin" ]; then
@@ -102,6 +97,27 @@ if [ "$BUILD_DOCS" = true ]; then
 	doxygen Doxyfile
 fi
 
+heading "Configuring libc" "1;33"
+
+mkdir -p build/lib/newlib
+cd build/lib/newlib
+../../../lib/newlib-cygwin/configure --target=x86_64-elf --prefix=/usr --disable-multilib
+
+heading "Building libc" "1;33"
+
+$MAKE all -j$NPROC
+$MAKE DESTDIR=$(pwd)/../../user tooldir=/usr install
+
+cd "$ROOTDIR"
+
+export CC=x86_64-elf-gcc
+export CXX=x86_64-elf-g++
+export LD=x86_64-elf-ld
+export AS=x86_64-elf-as
+export AR=x86_64-elf-ar
+
+$MAKE -j$NPROC lib
+
 heading "Building OS binaries" "1;33"
 
 $MAKE -j$NPROC kernel

lib/Makefile

@@ -0,0 +1,15 @@
+.PHONY: all libcos
+
+all: libcos
+
+libcos:
+	@echo "Building libcos..."
+	$(MAKE) -C cos
+
+format:
+	@echo "Formatting libcos..."
+	$(MAKE) -C cos format
+
+clean:
+	@echo "Cleaning libcos..."
+	$(MAKE) -C cos clean

lib/cos/Makefile

@@ -0,0 +1,110 @@
+# This makefile is quite similar to the one used by the kernel, with
+# the exception of some kernel-only flags that have been omitted here
+
+override MAKEFLAGS += -rR
+override TARGET := libcos.a
+
+define DEFAULT_VAR =
+	ifeq ($(origin $1),default)
+		override $(1) := $(2)
+	endif
+	ifeq ($(origin $1),undefined)
+		override $(1) := $(2)
+	endif
+endef
+
+override DEFAULT_CC := x86_64-elf-gcc
+$(eval $(call DEFAULT_VAR,CC,$(DEFAULT_CC)))
+
+override DEFAULT_AR := x86_64-elf-ar
+$(eval $(call DEFAULT_VAR,AR,$(DEFAULT_AR)))
+
+override DEFAULT_CFLAGS := -g -O2 -pipe
+$(eval $(call DEFAULT_VAR,CFLAGS,$(DEFAULT_CFLAGS)))
+
+# User controllable C preprocessor flags. We set none by default.
+override DEFAULT_CPPFLAGS :=
+$(eval $(call DEFAULT_VAR,CPPFLAGS,$(DEFAULT_CPPFLAGS)))
+
+# User controllable linker flags. We set none by default.
+override DEFAULT_LDFLAGS :=
+$(eval $(call DEFAULT_VAR,LDFLAGS,$(DEFAULT_LDFLAGS)))
+
+# Internal C flags that should not be changed by the user.
+override CFLAGS += \
+	-Wall \
+	-Wextra \
+	-Wstrict-prototypes \
+	-Wmissing-prototypes \
+	-Wmissing-declarations \
+	-std=gnu23 \
+	-ffreestanding \
+	-fno-stack-protector \
+	-fno-stack-check \
+	-fno-lto \
+	-fno-PIE \
+	-fno-PIC \
+	-m64 \
+	-march=x86-64 \
+	-mabi=sysv
+
+override SYSROOT := $(abspath ../../build/user)
+
+# Internal C preprocessor flags that should not be changed by the user.
+override CPPFLAGS := \
+	-I $(SYSROOT)/usr/include \
+	-I include \
+	-I. \
+	$(CPPFLAGS) \
+	-MMD \
+	-MP
+
+# Internal linker flags that should not be changed by the user.
+override LDFLAGS += \
+	-nostdlib \
+	-static \
+	-m elf_x86_64 \
+	-z max-page-size=0x1000
+
+ifeq ($(shell $(LD) --help 2>&1 | grep 'no-pie' >/dev/null 2>&1; echo $$?),0)
+	override LDFLAGS += -no-pie
+endif
+
+override CFILES := $(shell find -L . -type f -name '*.c')
+
+override BUILD_DIR := ../../build/lib/libcos
+override OUT_DIR := ../../build/user/usr/lib
+override COMMON_INCLUDE_DIR := ../../build/user/usr/include
+
+override OBJ := $(patsubst %.c,$(BUILD_DIR)/%.c.o,$(CFILES))
+override HEADER_DEPS := $(patsubst %.c,$(BUILD_DIR)/%.c.d,$(CFILES))
+
+.PHONY: all
+all: $(OUT_DIR)/$(TARGET) $(OUT_DIR)/crt0.o
+
+$(OUT_DIR)/crt0.o: src/crt0.S
+	@mkdir -p $(@D)
+	@printf "CC\t%s\n" $<
+	@$(CC) $(CFLAGS) $(CPPFLAGS) -c $< -o $@
+
+$(OUT_DIR)/$(TARGET): $(OBJ)
+	@mkdir -p $(@D)
+	@printf "AR\t%s\n" $@
+	@$(AR) rcs $@ $(OBJ)
+	@mkdir -p $(COMMON_INCLUDE_DIR)
+	@cp -R include/* $(COMMON_INCLUDE_DIR)/
+
+-include $(HEADER_DEPS)
+
+$(BUILD_DIR)/%.c.o: %.c
+	@mkdir -p $(@D)
+	@printf "CC\t%s\n" $<
+	@$(CC) $(CFLAGS) $(CPPFLAGS) -c $< -o $@
+
+.PHONY: clean
+clean:
+	rm -rf $(BUILD_DIR)
+
+.PHONY: format
+format:
+	find . -type f \( -name '*.c' -o -name '*.h' \) ! -name 'limine.h' -exec clang-format -i {} +

lib/cos/include/arch/x86_64-cos/fcntl.h

@@ -0,0 +1,6 @@
+#pragma once
+
+#define O_RDONLY 0x0000
+#define O_WRONLY 0x0001
+#define O_RDWR	 0x0002
+#define O_CREAT	 0x0040

lib/cos/include/arch/x86_64-cos/syscalls.h

@@ -0,0 +1,24 @@
+#pragma once
+
+#include <stdint.h>
+
+#define SYSCALL_SYS_EXIT	1
+#define SYSCALL_SYS_READ	3
+#define SYSCALL_SYS_WRITE	4
+#define SYSCALL_SYS_OPEN	5
+#define SYSCALL_SYS_CLOSE	6
+#define SYSCALL_SYS_LSEEK	19
+#define SYSCALL_SYS_GETPID	20
+#define SYSCALL_SYS_MKDIR	39
+#define SYSCALL_SYS_BRK		45
+#define SYSCALL_SYS_FORK	57
+#define SYSCALL_SCHED_YIELD 158
+
+static inline uint64_t syscall3 (uint64_t num, uint64_t arg1, uint64_t arg2, uint64_t arg3) {
+	uint64_t ret;
+	__asm__ volatile ("int $0x80"
+					  : "=a"(ret)
+					  : "a"(num), "D"(arg1), "S"(arg2), "d"(arg3) // rdi, rsi, rdx
+					  : "memory");
+	return ret;
+}

lib/cos/include/arch/x86_64-cos/unistd.h

@@ -0,0 +1,38 @@
+#pragma once
+
+#include <stddef.h>
+#include <stdint.h>
+
+typedef long		 ssize_t;
+typedef long		 off_t;
+typedef int			 pid_t;
+typedef unsigned int mode_t;
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+void  _exit (int status);
+pid_t fork (void);
+pid_t getpid (void);
+int	  sched_yield (void);
+
+int		open (const char* pathname, int flags, ...);
+int		close (int fd);
+ssize_t read (int fd, void* buf, size_t count);
+ssize_t write (int fd, const void* buf, size_t count);
+off_t	lseek (int fd, off_t offset, int whence);
+
+int mkdir (const char* pathname, mode_t mode);
+
+uint64_t brk (void* addr);
+void*	 sbrk (ptrdiff_t incr);
+
+// TODO: implement stubs
+int fstat (int file, struct stat* st);
+int isatty (int file);
+int kill (int pid, int sig);
+
+#ifdef __cplusplus
+}
+#endif

lib/cos/src/_exit.c

@@ -0,0 +1,4 @@
+#include <arch/x86_64-cos/syscalls.h>
+#include <arch/x86_64-cos/unistd.h>
+
+void _exit (int status) { (void)syscall3 (SYSCALL_SYS_EXIT, (uint64_t)status, 0, 0); }

lib/cos/src/brk.c

@@ -0,0 +1,4 @@
+#include <arch/x86_64-cos/syscalls.h>
+#include <arch/x86_64-cos/unistd.h>
+
+uint64_t brk (void* addr) { return syscall3 (SYSCALL_SYS_BRK, (uint64_t)addr, 0, 0); }

lib/cos/src/close.c

@@ -0,0 +1,4 @@
+#include <arch/x86_64-cos/syscalls.h>
+#include <arch/x86_64-cos/unistd.h>
+
+int close (int fd) { return (int)syscall3 (SYSCALL_SYS_CLOSE, (long)fd, 0, 0); }

lib/cos/src/crt0.S

@@ -0,0 +1,24 @@
+.section .text
+.global _start
+.type _start, @function
+
+.extern main
+.extern exit
+
+_start:
+    xor %ebp, %ebp
+    and $-16, %rsp
+
+    // TODO: pass actual values, when we support that in the kernel
+    xor %edi, %edi      // argc
+    xor %esi, %esi      // argv
+    xor %edx, %edx      // envp
+
+    call main
+
+    mov %eax, %edi
+    call exit
+
+.Lhang:
+    hlt
+    jmp .Lhang

lib/cos/src/fork.c

@@ -0,0 +1,4 @@
+#include <arch/x86_64-cos/syscalls.h>
+#include <arch/x86_64-cos/unistd.h>
+
+pid_t fork (void) { return (pid_t)syscall3 (SYSCALL_SYS_FORK, 0, 0, 0); }

lib/cos/src/getpid.c

@@ -0,0 +1,4 @@
+#include <arch/x86_64-cos/syscalls.h>
+#include <arch/x86_64-cos/unistd.h>
+
+pid_t getpid (void) { return (pid_t)syscall3 (SYSCALL_SYS_GETPID, 0, 0, 0); }

lib/cos/src/lseek.c

@@ -0,0 +1,6 @@
+#include <arch/x86_64-cos/syscalls.h>
+#include <arch/x86_64-cos/unistd.h>
+
+off_t lseek (int fd, off_t offset, int whence) {
+	return (off_t)syscall3 (SYSCALL_SYS_LSEEK, (long)fd, (long)offset, (long)whence);
+}

lib/cos/src/mkdir.c

@@ -0,0 +1,6 @@
+#include <arch/x86_64-cos/syscalls.h>
+#include <arch/x86_64-cos/unistd.h>
+
+int mkdir (const char* pathname, mode_t mode) {
+	return (int)syscall3 (SYSCALL_SYS_MKDIR, (long)pathname, (long)mode, 0);
+}

lib/cos/src/open.c

@@ -0,0 +1,17 @@
+#include <arch/x86_64-cos/fcntl.h>
+#include <arch/x86_64-cos/syscalls.h>
+#include <arch/x86_64-cos/unistd.h>
+#include <stdarg.h>
+
+int open (const char* pathname, int flags, ...) {
+	mode_t mode = 0;
+
+	if (flags & O_CREAT) {
+		va_list args;
+		va_start (args, flags);
+		mode = va_arg (args, mode_t);
+		va_end (args);
+	}
+
+	return (int)syscall3 (SYSCALL_SYS_OPEN, (long)pathname, (long)flags, (long)mode);
+}

lib/cos/src/read.c

@@ -0,0 +1,6 @@
+#include <arch/x86_64-cos/syscalls.h>
+#include <arch/x86_64-cos/unistd.h>
+
+ssize_t read (int fd, void* buf, size_t count) {
+	return syscall3 (SYSCALL_SYS_READ, (uint64_t)fd, (uint64_t)buf, (uint64_t)count);
+}

lib/cos/src/sbrk.c

@@ -0,0 +1,20 @@
+#include <arch/x86_64-cos/unistd.h>
+#include <errno.h>
+#include <sys/types.h>
+
+void* sbrk (ptrdiff_t incr) {
+	static char* heap_end = 0;
+	char*		 prev_heap_end;
+
+	if (heap_end == 0) heap_end = (char*)brk (0);
+
+	prev_heap_end = heap_end;
+
+	if (brk (heap_end + incr) < 0) {
+		errno = ENOMEM;
+		return (void*)-1;
+	}
+
+	heap_end += incr;
+	return (void*)prev_heap_end;
+}

lib/cos/src/sched_yield.c

@@ -0,0 +1,4 @@
+#include <arch/x86_64-cos/syscalls.h>
+#include <arch/x86_64-cos/unistd.h>
+
+int sched_yield (void) { return (int)syscall3 (SYSCALL_SCHED_YIELD, 0, 0, 0); }