From 891f1010bbdc1351bda8d2a6139094a14bdfd5e1 Mon Sep 17 00:00:00 2001
From: Danny Holman <dholman@gymli.org>
Date: Sat, 24 Feb 2024 14:47:25 -0600
Subject: kernel: string: add a strcpy function

Add an implmentation of strcpy. This function is used in several places
in the kernel to copy strings between memory addresses.

Signed-off-by: Danny Holman <dholman@gymli.org>
---
 Makefile                 |  1 +
 arch/i386/boot/boot.s    | 16 ++++++----------
 arch/i386/kernel/timer.c |  1 -
 include/kernel/string.h  |  1 +
 kernel/init.c            | 25 +++++++++++++++++++++----
 kernel/string.c          |  8 ++++++++
 6 files changed, 37 insertions(+), 15 deletions(-)

diff --git a/Makefile b/Makefile
index 5db0d5e..a0ce753 100644
--- a/Makefile
+++ b/Makefile
@@ -28,6 +28,7 @@ KERNEL_OBJS=$(KERNEL_ARCH_OBJS) \
 	    kernel/init.o \
 	    kernel/string.o \
 	    kernel/io.o \
+	    kernel/panic.o \
 	    kernel/mem.o \
 
 OBJS=$(ARCHDIR)/boot/crti.o \
diff --git a/arch/i386/boot/boot.s b/arch/i386/boot/boot.s
index 4b9106d..2d17f6a 100644
--- a/arch/i386/boot/boot.s
+++ b/arch/i386/boot/boot.s
@@ -76,25 +76,21 @@ _start:
 1:      hlt
         jmp 1b
 
-.global load_page_dir
-.type load_page_dir, @function
-load_page_dir:
+.global enable_paging
+.type enable_paging, @function
+enable_paging:
         pushl %ebp
         movl %esp, %ebp
 
         movl 8(%esp), %eax
         movl %eax, %cr3
 
-        movl %ebp, %esp
-        popl %ebp
-        ret
-
-.global enable_paging
-.type enable_paging, @function
-enable_paging:
         movl %cr0, %eax
         orl $0x80000001, %eax
         movl %eax, %cr0
+
+        movl $0, %eax
+        popl %ebp
         ret
 
 .global flush_gdt
diff --git a/arch/i386/kernel/timer.c b/arch/i386/kernel/timer.c
index 4aafed1..e93c291 100644
--- a/arch/i386/kernel/timer.c
+++ b/arch/i386/kernel/timer.c
@@ -1,7 +1,6 @@
 #include <kernel/timer.h>
 #include <kernel/asm.h>
 #include <kernel/pic.h>
-#include <kernel/sched.h>
 
 static uint32_t num_ticks = 0;
 
diff --git a/include/kernel/string.h b/include/kernel/string.h
index f9a8eed..76bf610 100644
--- a/include/kernel/string.h
+++ b/include/kernel/string.h
@@ -10,6 +10,7 @@ void* memset(void *str, int c, size_t n);
 int strncmp(const char *str1, const char *str2, size_t n);
 int strcmp(const char *str1, const char *str2);
 size_t strlen(const char *str);
+char* strncpy(char* __restrict dest, const char* __restrict src, size_t n);
 char* strcpy(char* __restrict dest, const char* __restrict src);
 char* strcat(char* __restrict dest, const char* __restrict src);
 char* strtok(char* __restrict str, const char* __restrict delim);
diff --git a/kernel/init.c b/kernel/init.c
index 195ce92..86567a4 100644
--- a/kernel/init.c
+++ b/kernel/init.c
@@ -1,8 +1,25 @@
-#include <kernel/tty.h>
 #include <kernel/io.h>
+#include <kernel/mem.h>
+#include <kernel/string.h>
 #include <kernel/serial.h>
 
-void kernel_main(void) {
-        tty_init();
-        kprintf("Hello world\n");
+void jump_userspace(void);
+
+char rootfs[1024];
+
+int start_init(int argc, char* argv[]) {
+        return 0;
+}
+
+void process_cmd(char *cmdline) {
+        char *token = strtok(cmdline, " ");
+        while (token != NULL) {
+                if (strncmp(token, "root=", 5) == 0)
+                        strcpy(rootfs, &token[6]);
+        }
+}
+
+void kernel_main(char *cmdline) {
+        kprintf("Box Kernel version %s\n", VERSION);
+        serial_init();
 }
diff --git a/kernel/string.c b/kernel/string.c
index 35dc16e..fa0fd3f 100644
--- a/kernel/string.c
+++ b/kernel/string.c
@@ -31,6 +31,14 @@ void* memcpy(void* __restrict dest, const void* __restrict src, size_t n) {
         return dest;
 }
 
+char* strncpy(char* __restrict dest, const char* __restrict src, size_t n) {
+        for (int i = 0; i < n; i++) {
+                if (src[i] == '\0')
+                        break;
+                dest[i] = src[i];
+        }
+}
+
 char* strcpy(char* __restrict dest, const char* __restrict src) {
         if (strlen(src) > strlen(dest))
                 return NULL;
-- 
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