From c17a2f4c6cae5eacd327e54eb927b5b20bc2d189 Mon Sep 17 00:00:00 2001
From: Matheus <matheusuky@gmail.com>
Date: Tue, 13 Dec 2022 23:41:40 -0300
Subject: [PATCH] kernel: user safe strlen

---
 src/arch/x86_64/Makefile     |  7 ++++++-
 src/arch/x86_64/ustring.asm  | 19 +++++++++++++++++++
 src/include/kernel/sched.h   |  2 ++
 src/include/kernel/ustring.h |  9 +++++++++
 src/sys/ustring.c            | 19 +++++++++++++++++++
 5 files changed, 55 insertions(+), 1 deletion(-)
 create mode 100644 src/arch/x86_64/ustring.asm
 create mode 100644 src/include/kernel/ustring.h
 create mode 100644 src/sys/ustring.c

diff --git a/src/arch/x86_64/Makefile b/src/arch/x86_64/Makefile
index ef5c74e6..91757044 100644
--- a/src/arch/x86_64/Makefile
+++ b/src/arch/x86_64/Makefile
@@ -1,4 +1,4 @@
-objects := $(patsubst %.c,%.o,$(wildcard *.c)) israsm.o context.o syscall.o sched.o
+objects := $(patsubst %.c,%.o,$(wildcard *.c)) israsm.o context.o syscall.o sched.o ustringasm.o
 subdirs=boot
 OBJPATH=$(OBJDIR)/arch/${TARGET}/
 export
@@ -27,3 +27,8 @@ sched.o: sched.asm
 	nasm -f elf64 -o $@ $<
 	mkdir -p $(OBJPATH)
 	cp $@ $(OBJPATH)/$@
+
+ustringasm.o: ustring.asm
+	nasm -f elf64 -o $@ $<
+	mkdir -p $(OBJPATH)
+	cp $@ $(OBJPATH)/$@
diff --git a/src/arch/x86_64/ustring.asm b/src/arch/x86_64/ustring.asm
new file mode 100644
index 00000000..346f5c54
--- /dev/null
+++ b/src/arch/x86_64/ustring.asm
@@ -0,0 +1,19 @@
+section .text:
+
+global arch_u_strlen
+global arch_u_strlen_cont
+
+arch_u_strlen:
+    xor rcx, rcx
+   .loop:
+        cmp byte [rdi],0
+        je .done
+        inc rcx
+        inc rdi
+    .done:
+    mov [rsi], rcx
+    xor rax, rax
+    ret
+arch_u_strlen_cont:
+    mov rax, 1
+    ret
diff --git a/src/include/kernel/sched.h b/src/include/kernel/sched.h
index 4e18b099..21829e07 100644
--- a/src/include/kernel/sched.h
+++ b/src/include/kernel/sched.h
@@ -42,6 +42,8 @@ typedef struct _thread_t{
 	vmm_context* ctx;
 	pid_t tid;
 	int priority;
+	int umemoperror;
+	void (*umemopfailaddr)();
 } thread_t;
 
 typedef struct _proc_t{
diff --git a/src/include/kernel/ustring.h b/src/include/kernel/ustring.h
new file mode 100644
index 00000000..67098a1c
--- /dev/null
+++ b/src/include/kernel/ustring.h
@@ -0,0 +1,9 @@
+#ifndef _USTRING_H_INCLUDE
+#define _USTRING_H_INCLUDE
+
+#include <stddef.h>
+
+int u_strlen(const char* str, size_t* size);
+
+
+#endif
diff --git a/src/sys/ustring.c b/src/sys/ustring.c
new file mode 100644
index 00000000..8505fa12
--- /dev/null
+++ b/src/sys/ustring.c
@@ -0,0 +1,19 @@
+#include <kernel/ustring.h>
+#include <arch/cls.h>
+
+extern void arch_u_strlen_cont();
+extern int arch_u_strlen(const char* str, size_t* len);
+
+int u_strlen(const char* str, size_t* len){
+    
+	arch_getcls()->thread->umemopfailaddr = arch_u_strlen_cont;
+
+	int ret = arch_u_strlen(str, len);
+
+	arch_getcls()->thread->umemopfailaddr = NULL;
+
+	return ret == 0 ? 0 : arch_getcls()->thread->umemoperror;
+    
+}
+
+