From 65167272a3ba52dc4d032a1c60a9ff030408047d Mon Sep 17 00:00:00 2001 From: Silvino Silva Date: Wed, 2 Aug 2017 01:01:58 +0100 Subject: first hardened test --- dev/c/index.html | 90 ++++++++++++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 87 insertions(+), 3 deletions(-) (limited to 'dev/c') diff --git a/dev/c/index.html b/dev/c/index.html index 09374c6..684c7d2 100644 --- a/dev/c/index.html +++ b/dev/c/index.html @@ -7,6 +7,92 @@ Development Index +

System Development

+ +

System development requires debug kernel know how, + in this example will be used qemu and gdb. A simple init + program is created. Create init.S;

+ + 
+	.global _start
+	_start:
+	    mov $1, %rax
+	    mov $1, %rdi
+	    mov $message, %rsi
+	    mov $message_len, %rdx
+	    syscall
+	    jmp .
+	    message: .ascii "FOOBAR FOOBAR FOOBAR FOOBAR FOOBAR FOOBAR FOOBAR\n"
+	    .equ message_len, . - message
+
+ +

Assemble, link and create simple initial ram disk;

+ + 
+	mkdir d
+	as --64 -o init.o init.S # assemble
+	ld -o d/init init.o      # link
+	cd d
+	find . | cpio -o -H newc | gzip > ../rootfs.cpio.gz
+
+ +

Clean temporary directory;

+ + 
+	cd ..
+	rm -r d/
+
+ +

Can be used C to create init program;

+ + 
+	#include <stdio.h>
+	#include <unistd.h>
+
+	int main() {
+	    printf("FOOBAR FOOBAR FOOBAR FOOBAR FOOBAR FOOBAR FOOBAR\n");
+	    sleep(0xFFFFFFFF);
+	    return 0;
+	}
+
+ + 
+	$ gcc -static init.c -o init
+
+ +

Test qemu, kernel and simple init program, you should see + "FOOBAR FOOBAR FOOBAR FOOBAR FOOBAR FOOBAR FOOBAR";

+ + 
+	$ qemu-system-x86_64 -enable-kvm --kernel arch/x86_64/boot/bzImage \
+    	--initrd rootfs.cpio.gz
+
+ +

If everything goes well you can start qemu without start CPU at + startup (-S) and with gdb server on TCP port 1234 (-s).

+ + 
+	$ qemu-system-x86_64 -enable-kvm --kernel arch/x86/boot/bzImage \
+                --initrd rootfs.cpio.gz \
+		-S -s
+
+ +

On another terminal start gdb;

+ + 
+	gdb \
+	    -ex "add-auto-load-safe-path $(pwd)" \
+	    -ex "file vmlinux" \
+	    -ex 'set arch i386:x86-64:intel' \
+	    -ex 'target remote localhost:1234' \
+	    -ex 'break start_kernel' \
+	    -ex 'continue' \
+	    -ex 'disconnect' \
+	    -ex 'set arch i386:x86-64' \
+	    -ex 'target remote localhost:1234'
+
+ +

C & GDB

C program with autotools @@ -74,7 +160,7 @@ thread 1 -

Stopping and Starting +

Stopping and Starting multi-thread programs

@@ -86,8 +172,6 @@
         
         strace -c ./program
         

-
-
         Development Index
         

         This is part of the c9-doc Manual.
-- 
cgit 1.4.1-2-gfad0