From 47c93d4cef1ce4a36cd7c05bda05279b84aa9d3d Mon Sep 17 00:00:00 2001
From: hinus <hinus@163.com>
Date: Fri, 30 Jul 2021 00:39:08 +0800
Subject: [PATCH] Title: System call 'brk' Issue:
 https://gitee.com/hinus/linux_kernel_011/issues/I42HQT Description: sys_brk
 and show sys_call index.

---
 include/linux/sys.h | 4 ++--
 kernel/sys.c        | 7 +++++++
 kernel/sys_call.S   | 9 +++++++++
 3 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/include/linux/sys.h b/include/linux/sys.h
index 0a65c9c..e2e4712 100644
--- a/include/linux/sys.h
+++ b/include/linux/sys.h
@@ -43,7 +43,7 @@ extern int sys_dup();
 //extern int sys_pipe();
 //extern int sys_times();
 //extern int sys_prof();
-//extern int sys_brk();
+extern int sys_brk();
 //extern int sys_setgid();
 //extern int sys_getgid();
 extern int sys_signal();
@@ -138,7 +138,7 @@ fn_ptr sys_call_table[] = {
     0, //    sys_pipe,
     0, //    sys_times,
     0, //    sys_prof,
-    0, //    sys_brk,
+    sys_brk,
     0, //    sys_setgid,
 
     0, //    sys_getgid,
diff --git a/kernel/sys.c b/kernel/sys.c
index 8c89258..c853687 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -20,6 +20,13 @@ int sys_ulimit() {
     return -ENOSYS;
 }
 
+int sys_brk(unsigned long end_data_seg) {
+    if (end_data_seg >= current->end_code &&
+            end_data_seg < current->start_stack - 16384)
+        current->brk = end_data_seg;
+    return current->brk;
+}
+
 int in_group_p(gid_t grp) {
     int i;
     if (grp == current->egid)
diff --git a/kernel/sys_call.S b/kernel/sys_call.S
index cb4298d..1f0ca52 100644
--- a/kernel/sys_call.S
+++ b/kernel/sys_call.S
@@ -20,6 +20,9 @@ OLDSS      = 0x30
 int_msg:
     .asciz  "In kernel interrupt\n\r"
 
+show_ind:
+    .asciz  "sys call %d\n"
+
 system_call:
     pushl %ds
     pushl %es
@@ -34,6 +37,12 @@ system_call:
     movl  $0x17, %edx
     movw  %dx, %fs
 
+    pushl %eax
+    pushl $show_ind
+    call    printk
+    popl  %eax
+    popl  %eax
+
     call *sys_call_table(, %eax, 4)
     pushl %eax
 
-- 
Gitee