Initial commit. We have a booting kernel

This commit is contained in:
Bananymous 2022-11-12 21:04:47 +02:00
commit e6b4866ab0
36 changed files with 691 additions and 0 deletions

3
.gitignore vendored Normal file
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*.iso
isodir
sysroot

7
build.sh Executable file
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#!/bin/sh
set -e
. ./headers.sh
for PROJECT in $PROJECTS; do
(cd $PROJECT && DESTDIR="$SYSROOT" $MAKE install)
done

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clean.sh Executable file
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#!/bin/sh
set -e
. ./config.sh
for PROJECT in $PROJECTS; do
(cd $PROJECT && $MAKE clean)
done
rm -rf sysroot
rm -rf isodir
rm -rf banan-os.iso

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config.sh Normal file
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SYSTEM_HEADER_PROJECTS="libc kernel"
PROJECTS="libc kernel"
export MAKE=${MAKE:-make}
export HOST=${HOST:-$(./default-host.sh)}
export AR=${HOST}-ar
export AS=${HOST}-as
export CC=${HOST}-gcc
export PREFIX=/usr
export EXEC_PREFIX=$PREFIX
export BOOTDIR=/boot
export LIBDIR=$EXEC_PREFIX/lib
export INCLUDEDIR=$PREFIX/include
export CFLAGS='-O2 -g'
export CPPFLAGS=''
# Configure the cross-compiler to use the desired system root.
export SYSROOT="$(pwd)/sysroot"
export CC="$CC --sysroot=$SYSROOT"
# Work around that the -elf gcc targets doesn't have a system include directory
# because it was configured with --without-headers rather than --with-sysroot.
if echo "$HOST" | grep -Eq -- '-elf($|-)'; then
export CC="$CC -isystem=$INCLUDEDIR"
fi

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default-host.sh Executable file
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#!/bin/sh
echo i686-elf

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headers.sh Executable file
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#!/bin/sh
set -e
. ./config.sh
mkdir -p "$SYSROOT"
for PROJECT in $SYSTEM_HEADER_PROJECTS; do
(cd $PROJECT && DESTDIR="$SYSROOT" $MAKE install-headers)
done

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iso.sh Executable file
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#!/bin/sh
set -e
. ./build.sh
mkdir -p isodir
mkdir -p isodir/boot
mkdir -p isodir/boot/grub
cp sysroot/boot/banan-os.kernel isodir/boot/banan-os.kernel
cat > isodir/boot/grub/grub.cfg << EOF
menuentry "banan-os" {
multiboot /boot/banan-os.kernel
}
EOF
grub-mkrescue -o banan-os.iso isodir

3
kernel/.gitignore vendored Normal file
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*.d
*.kernel
*.o

83
kernel/Makefile Normal file
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DEFAULT_HOST!=../default-host.sh
HOST?=DEFAULT_HOST
HOSTARCH!=../target-triplet-to-arch.sh $(HOST)
CFLAGS?=-O2 -g
CPPFLAGS?=
LDFLAGS?=
LIBS?=
DESTDIR?=
PREFIX?=/usr/local
EXEC_PREFIX?=$(PREFIX)
BOOTDIR?=$(EXEC_PREFIX)/boot
INCLUDEDIR?=$(PREFIX)/include
CFLAGS:=$(CFLAGS) -ffreestanding -Wall -Wextra
CPPFLAGS:=$(CPPFLAGS) -D__is_kernel -Iinclude
LDFLAGS:=$(LDFLAGS)
LIBS:=$(LIBS) -nostdlib -lk -lgcc
ARCHDIR=arch/$(HOSTARCH)
include $(ARCHDIR)/make.config
CFLAGS:=$(CFLAGS) $(KERNEL_ARCH_CFLAGS)
CPPFLAGS:=$(CPPFLAGS) $(KERNEL_ARCH_CPPFLAGS)
LDFLAGS:=$(LDFLAGS) $(KERNEL_ARCH_LDFLAGS)
LIBS:=$(LIBS) $(KERNEL_ARCH_LIBS)
KERNEL_OBJS=\
$(KERNEL_ARCH_OBJS) \
kernel/kernel.o \
OBJS=\
$(ARCHDIR)/crti.o \
$(ARCHDIR)/crtbegin.o \
$(KERNEL_OBJS) \
$(ARCHDIR)/crtend.o \
$(ARCHDIR)/crtn.o \
LINK_LIST=\
$(LDFLAGS) \
$(ARCHDIR)/crti.o \
$(ARCHDIR)/crtbegin.o \
$(KERNEL_OBJS) \
$(LIBS) \
$(ARCHDIR)/crtend.o \
$(ARCHDIR)/crtn.o \
.PHONY: all clean install install-headers install-kernel
.SUFFIXES: .o .c .cpp .S
all: banan-os.kernel
banan-os.kernel: $(OBJS) $(ARCHDIR)/linker.ld
$(CC) -T $(ARCHDIR)/linker.ld -o $@ $(CFLAGS) $(LINK_LIST)
grub-file --is-x86-multiboot banan-os.kernel
$(ARCHDIR)/crtbegin.o $(ARCHDIR)/crtend.o:
OBJ=`$(CC) $(CFLAGS) $(LDFLAGS) -print-file-name=$(@F)` && cp "$$OBJ" $@
.c.o:
$(CC) -MD -c $< -o $@ -std=gnu11 $(CFLAGS) $(CPPFLAGS)
.S.o:
$(CC) -MD -c $< -o $@ $(CFLAGS) $(CPPFLAGS)
clean:
rm -f banan-os.kernel
rm -f $(OBJS) *.o */*.o */*/*.o
rm -f $(OBJS:.o=.d) *.d */*.d */*/*.d
install: install-headers install-kernel
install-headers:
mkdir -p $(DESTDIR)$(INCLUDEDIR)
cp -R --preserve=timestamps include/. $(DESTDIR)$(INCLUDEDIR)/.
install-kernel: banan-os.kernel
mkdir -p $(DESTDIR)$(BOOTDIR)
cp banan-os.kernel $(DESTDIR)$(BOOTDIR)
-include $(OBJS:.o=.d)

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kernel/arch/i386/boot.s Normal file
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/* Declare constants for the multiboot header. */
.set ALIGN, 1<<0 /* align loaded modules on page boundaries */
.set MEMINFO, 1<<1 /* provide memory map */
.set MB_FLAGS, ALIGN | MEMINFO /* this is the Multiboot 'flag' field */
.set MB_MAGIC, 0x1BADB002 /* 'magic number' lets bootloader find the header */
.set MB_CHECKSUM, -(MB_MAGIC + MB_FLAGS) /* checksum of above, to prove we are multiboot */
/* Multiboot header */
.section .multiboot
.align 4
.long MB_MAGIC
.long MB_FLAGS
.long MB_CHECKSUM
/* Create stack */
.section .bss
.align 16
stack_bottom:
.skip 16384 # 16 KiB
stack_top:
/* Entrypoint */
.section .text
.global _start
.type _start, @function
_start:
/* Setup stack */
mov $stack_top, %esp
/* Call into C code */
call kernel_main
/* Hang if kernel_main returns */
cli
1: hlt
jmp 1b
.size _start, . - _start

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kernel/arch/i386/crti.s Normal file
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/* x86 crti.s */
.section .init
.global _init
.type _init, @function
_init:
push %ebp
movl %esp, %ebp
/* gcc will nicely put the contents of crtbegin.o's .init section here. */
.section .fini
.global _fini
.type _fini, @function
_fini:
push %ebp
movl %esp, %ebp
/* gcc will nicely put the contents of crtbegin.o's .fini section here. */

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kernel/arch/i386/crtn.s Normal file
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/* x86 crtn.s */
.section .init
/* gcc will nicely put the contents of crtend.o's .init section here. */
popl %ebp
ret
.section .fini
/* gcc will nicely put the contents of crtend.o's .fini section here. */
popl %ebp
ret

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ENTRY(_start)
SECTIONS
{
. = 1M;
.text BLOCK(4K) : ALIGN(4K)
{
*(.multiboot)
*(.text)
}
.rodata BLOCK(4K) : ALIGN(4K)
{
*(.rodata)
}
.data BLOCK(4K) : ALIGN(4K)
{
*(.data)
}
.bss BLOCK(4K) : ALIGN(4K)
{
*(COMMON)
*(.bss)
}
}

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KERNEL_ARCH_CFLAGS=
KERNEL_ARCH_CPPFLAGS=
KERNEL_ARCH_LDFLAGS=
KERNEL_ARCH_LIBS=
KERNEL_ARCH_OBJS=\
$(ARCHDIR)/boot.o \
$(ARCHDIR)/tty.o \

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kernel/arch/i386/tty.c Normal file
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#include <kernel/tty.h>
#include "vga.h"
#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>
static const size_t VGA_WIDTH = 80;
static const size_t VGA_HEIGHT = 25;
static uint16_t* const VGA_MEMORY = (uint16_t*)0xB8000;
static size_t terminal_row;
static size_t terminal_col;
static uint8_t terminal_color;
static uint16_t* terminal_buffer;
void terminal_putentryat(unsigned char c, uint8_t color, size_t x, size_t y)
{
const size_t index = y * VGA_WIDTH + x;
terminal_buffer[index] = vga_entry(c, color);
}
void terminal_clear(void)
{
for (size_t y = 0; y < VGA_HEIGHT; y++)
for (size_t x = 0; x < VGA_WIDTH; x++)
terminal_putentryat(' ', terminal_color, x, y);
}
void terminal_initialize(void)
{
terminal_row = 0;
terminal_col = 0;
terminal_color = vga_entry_color(VGA_COLOR_WHITE, VGA_COLOR_BLACK);
terminal_buffer = VGA_MEMORY;
terminal_clear();
}
void terminal_setcolor(uint8_t color)
{
terminal_color = color;
}
void terminal_scroll_line(size_t line)
{
for (size_t x = 0; x < VGA_WIDTH; x++)
{
const size_t index = line * VGA_WIDTH + x;
terminal_buffer[index - VGA_WIDTH] = terminal_buffer[index];
}
}
void terminal_clear_line(size_t line)
{
for (size_t x = 0; x < VGA_WIDTH; x++)
terminal_putentryat(' ', terminal_color, x, line);
}
void terminal_putchar(char c)
{
if (c == '\n')
{
terminal_col = 0;
terminal_row++;
}
else
{
terminal_putentryat(c, terminal_color, terminal_col, terminal_row);
terminal_col++;
}
if (terminal_col == VGA_WIDTH)
{
terminal_col = 0;
terminal_row++;
}
if (terminal_row == VGA_HEIGHT)
{
for (size_t line = 1; line < VGA_HEIGHT; line++)
terminal_scroll_line(line);
terminal_clear_line(VGA_HEIGHT - 1);
terminal_col = 0;
terminal_row = VGA_HEIGHT - 1;
}
}
void terminal_write(const char* data, size_t size)
{
for (size_t i = 0; i < size; i++)
terminal_putchar(data[i]);
}
void terminal_writestring(const char* data)
{
size_t len = 0;
while (data[len])
len++;
terminal_write(data, len);
}

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kernel/arch/i386/vga.h Normal file
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#pragma once
#include <stdint.h>
enum vga_color
{
VGA_COLOR_BLACK = 0,
VGA_COLOR_BLUE = 1,
VGA_COLOR_GREEN = 2,
VGA_COLOR_CYAN = 3,
VGA_COLOR_RED = 4,
VGA_COLOR_MAGENTA = 5,
VGA_COLOR_BROWN = 6,
VGA_COLOR_LIGHT_GREY = 7,
VGA_COLOR_DARK_GREY = 8,
VGA_COLOR_LIGHT_BLUE = 9,
VGA_COLOR_LIGHT_GREEN = 10,
VGA_COLOR_LIGHT_CYAN = 11,
VGA_COLOR_LIGHT_RED = 12,
VGA_COLOR_LIGHT_MAGENTA = 13,
VGA_COLOR_LIGHT_BROWN = 14,
VGA_COLOR_WHITE = 15,
};
static inline uint8_t vga_entry_color(enum vga_color fg, enum vga_color bg)
{
return fg | bg << 4;
}
static inline uint16_t vga_entry(unsigned char uc, uint8_t color)
{
return (uint16_t) uc | (uint16_t) color << 8;
}

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#pragma once
#include <stddef.h>
void terminal_initialize(void);
void terminal_putchar(char c);
void terminal_write(const char* data, size_t size);
void terminal_writestring(const char* data);

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kernel/kernel/kernel.c Normal file
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#include <kernel/tty.h>
#include <stdio.h>
void kernel_main()
{
terminal_initialize();
printf("Hello from the kernel!\n");
}

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libc/.gitignore vendored Normal file
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*.a
*.d
*.o

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libc/Makefile Normal file
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DEFAULT_HOST!=../default-host.sh
HOST?=DEFAULT_HOST
HOSTARCH!=../target-triplet-to-arch.sh $(HOST)
CFLAGS?=-O2 -g
CPPFLAGS?=
LDFLAGS?=
LIBS?=
DESTDIR?=
PREFIX?=/usr/local
EXEC_PREFIX?=$(PREFIX)
INCLUDEDIR?=$(PREFIX)/include
LIBDIR?=$(EXEC_PREFIX)/lib
CFLAGS:=$(CFLAGS) -ffreestanding -Wall -Wextra
CPPFLAGS:=$(CPPFLAGS) -D__is_libc -Iinclude
LIBK_CFLAGS:=$(CFLAGS)
LIBK_CPPFLAGS:=$(CPPFLAGS) -D__is_libk
ARCHDIR=arch/$(HOSTARCH)
include $(ARCHDIR)/make.config
CFLAGS:=$(CFLAGS) $(ARCH_CFLAGS)
CPPFLAGS:=$(CPPFLAGS) $(ARCH_CPPFLAGS)
LIBK_CFLAGS:=$(LIBK_CFLAGS) $(KERNEL_ARCH_CFLAGS)
LIBK_CPPFLAGS:=$(LIBK_CPPFLAGS) $(KERNEL_ARCH_CPPFLAGS)
FREEOBJS=\
$(ARCH_FREEOBJS) \
stdio/printf.o \
stdio/putchar.o \
stdio/puts.o \
stdlib/abort.o \
string/memcmp.o \
string/memcpy.o \
string/memmove.o \
string/memset.o \
string/strlen.o \
HOSTEDOBJS=\
$(ARCH_HOSTEDOBJS) \
OBJS=\
$(FREEOBJS) \
$(HOSTEDOBJS) \
LIBK_OBJS=$(FREEOBJS:.o=.libk.o)
#BINARIES=libc.a libk.a # Not ready for libc yet.
BINARIES=libk.a
.PHONY: all clean install install-headers install-libs
.SUFFIXES: .o .libk.o .c .S
all: $(BINARIES)
libc.a: $(OBJS)
$(AR) rcs $@ $(OBJS)
libk.a: $(LIBK_OBJS)
$(AR) rcs $@ $(LIBK_OBJS)
.c.o:
$(CC) -MD -c $< -o $@ -std=gnu11 $(CFLAGS) $(CPPFLAGS)
.S.o:
$(CC) -MD -c $< -o $@ $(CFLAGS) $(CPPFLAGS)
.c.libk.o:
$(CC) -MD -c $< -o $@ -std=gnu11 $(LIBK_CFLAGS) $(LIBK_CPPFLAGS)
.S.libk.o:
$(CC) -MD -c $< -o $@ $(LIBK_CFLAGS) $(LIBK_CPPFLAGS)
clean:
rm -f $(BINARIES) *.a
rm -f $(OBJS) $(LIBK_OBJS) *.o */*.o */*/*.o
rm -f $(OBJS:.o=.d) $(LIBK_OBJS:.o=.d) *.d */*.d */*/*.d
install: install-headers install-libs
install-headers:
mkdir -p $(DESTDIR)$(INCLUDEDIR)
cp -R --preserve=timestamps include/. $(DESTDIR)$(INCLUDEDIR)/.
install-libs: $(BINARIES)
mkdir -p $(DESTDIR)$(LIBDIR)
cp $(BINARIES) $(DESTDIR)$(LIBDIR)
-include $(OBJS:.o=.d)
-include $(LIBK_OBJS:.o=.d)

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ARCH_CFLAGS=
ARCH_CPPFLAGS=
KERNEL_ARCH_CFLAGS=
KERNEL_ARCH_CPPFLAGS=
ARCH_FREEOBJS=\
ARCH_HOSTEDOBJS=\

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#pragma once
#include <sys/cdefs.h>
#define EOF (-1)
#ifdef __cplusplus
extern "C" {
#endif
int printf(const char* __restrict, ...);
int putchar(int);
int puts(const char*);
#ifdef __cplusplus
}
#endif

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#pragma once
#include <sys/cdefs.h>
#ifdef __cplusplus
extern "C" {
#endif
__attribute__((__noreturn__))
void abort(void);
#ifdef __cplusplus
}
#endif

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libc/include/string.h Normal file
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#pragma once
#include <stddef.h>
#include <sys/cdefs.h>
#ifdef __cplusplus
extern "C" {
#endif
int memcmp(const void*, const void*, size_t);
void* memcpy(void* __restrict, const void* __restrict, size_t);
void* memmove(void*, const void*, size_t);
void* memset(void*, int, size_t);
size_t strlen(const char*);
#ifdef __cplusplus
}
#endif

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libc/include/sys/cdefs.h Normal file
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#pragma once
#define __banan_libc 1

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libc/stdio/printf.c Normal file
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#include <stdio.h>
int printf(const char* restrict fmt, ...)
{
int len = 0;
while (fmt[len])
putchar(fmt[len++]);
return len;
}

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libc/stdio/putchar.c Normal file
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#include <stdio.h>
#if defined(__is_libk)
#include <kernel/tty.h>
#endif
int putchar(int c)
{
#if defined(__is_libk)
char ch = (char)c;
terminal_write(&ch, sizeof(ch));
#else
#endif
return c;
}

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libc/stdio/puts.c Normal file
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#include <stdio.h>
int puts(const char* str)
{
return printf("%s\n", str);
}

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libc/stdlib/abort.c Normal file
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#include <stdlib.h>
#include <stdio.h>
__attribute__((__noreturn__))
void abort(void)
{
#if defined(__is_libk)
printf("Kernel panic: abort()\n");
asm volatile("hlt");
#else
printf("abort()\n");
#endif
while (1);
__builtin_unreachable();
}

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libc/string/memcmp.c Normal file
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#include <string.h>
int memcmp(const void* s1, const void* s2, size_t n)
{
const unsigned char* a = s1;
const unsigned char* b = s2;
while (n--)
{
if (*a != *b)
return *a - *b;
a++;
b++;
}
return 0;
}

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libc/string/memcpy.c Normal file
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#include <string.h>
void* memcpy(void* restrict destp, const void* restrict srcp, size_t n)
{
unsigned char* dest = (unsigned char*)destp;
const unsigned char* src = (const unsigned char*)srcp;
for (size_t i = 0; i < n; i++)
dest[i] = src[i];
return destp;
}

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libc/string/memmove.c Normal file
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#include <string.h>
void* memmove(void* destp, const void* srcp, size_t n)
{
unsigned char* dest = (unsigned char*)destp;
const unsigned char* src = (const unsigned char*)srcp;
if (dest < src)
{
for (size_t i = 0; i < n; i++)
dest[i] = src[i];
}
else
{
for (size_t i = 1; i <= n; i++)
dest[n - i] = src[n - i];
}
return destp;
}

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libc/string/memset.c Normal file
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#include <string.h>
void* memset(void* s, int c, size_t n)
{
unsigned char* p = (unsigned char*)s;
for (size_t i = 0; i < n; i++)
p[i] = c;
return s;
}

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libc/string/strlen.c Normal file
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#include <string.h>
size_t strlen(const char* str)
{
size_t len = 0;
while (str[len])
len++;
return len;
}

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#!/bin/sh
set -e
. ./iso.sh
qemu-system-$(./target-triplet-to-arch.sh $HOST) -cdrom banan-os.iso

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target-triplet-to-arch.sh Executable file
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#!/bin/sh
if echo "$1" | grep -Eq 'i[[:digit:]]86-'; then
echo i386
else
echo "$1" | grep -Eo '^[[:alnum:]_]*'
fi