From 003811e0ea2fec2afb2b8786a528067c0a26ee4b Mon Sep 17 00:00:00 2001
From: hinus <hinus@163.com>
Date: Fri, 6 Aug 2021 11:14:43 +0800
Subject: [PATCH] Title: System call chown. Issue:
 https://gitee.com/hinus/linux_kernel_011/issues/I43DC1 Description: System
 call, chown, chroot, chmod

---
 fs/open.c           | 56 +++++++++++++++++++++++++++++++++++++++++++++
 include/linux/sys.h | 12 +++++-----
 2 files changed, 62 insertions(+), 6 deletions(-)

diff --git a/fs/open.c b/fs/open.c
index 999d441..b0d56d6 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -1,5 +1,7 @@
 #include <string.h>
 #include <errno.h>
+#include <fcntl.h>
+#include <sys/types.h>
 
 #include <linux/sched.h>
 #include <linux/tty.h>
@@ -9,6 +11,60 @@
 
 #include <asm/segment.h>
 
+int sys_ustat(int dev, struct ustat * ubuf) {
+    return -ENOSYS;
+}
+
+int sys_chroot(const char * filename) {
+    struct m_inode * inode;
+
+    if (!(inode=namei(filename)))
+        return -ENOENT;
+
+    if (!S_ISDIR(inode->i_mode)) {
+        iput(inode);
+        return -ENOTDIR;
+    }
+
+    iput(current->root);
+    current->root = inode;
+    return 0;
+}
+
+int sys_chmod(const char * filename,int mode) {
+    struct m_inode * inode;
+
+    if (!(inode=namei(filename)))
+        return -ENOENT;
+
+    if ((current->euid != inode->i_uid) && !suser()) {
+        iput(inode);
+        return -EACCES;
+    }
+
+    inode->i_mode = (mode & 07777) | (inode->i_mode & ~07777);
+    inode->i_dirt = 1;
+    iput(inode);
+    return 0;
+}
+
+int sys_chown(const char * filename,int uid,int gid) {
+    struct m_inode * inode;
+
+    if (!(inode=namei(filename)))
+        return -ENOENT;
+    if (!suser()) {
+        iput(inode);
+        return -EACCES;
+    }
+
+    inode->i_uid=uid;
+    inode->i_gid=gid;
+    inode->i_dirt=1;
+    iput(inode);
+    return 0;
+}
+
 int sys_chdir(const char * filename) {
     struct m_inode * inode;
     if (!(inode = namei(filename)))
diff --git a/include/linux/sys.h b/include/linux/sys.h
index 3c7ba08..291b74a 100644
--- a/include/linux/sys.h
+++ b/include/linux/sys.h
@@ -13,8 +13,8 @@ extern int sys_execve();
 extern int sys_chdir();
 extern int sys_time();
 //extern int sys_mknod();
-//extern int sys_chmod();
-//extern int sys_chown();
+extern int sys_chmod();
+extern int sys_chown();
 //extern int sys_break();
 //extern int sys_stat();
 //extern int sys_lseek();
@@ -59,7 +59,7 @@ extern int sys_ioctl();
 extern int sys_ulimit();
 //extern int sys_uname();
 //extern int sys_umask();
-//extern int sys_chroot();
+extern int sys_chroot();
 //extern int sys_ustat();
 //extern int sys_dup2();
 extern int sys_getppid();
@@ -103,9 +103,9 @@ fn_ptr sys_call_table[] = {
     sys_chdir,
     sys_time,
     0, //sys_mknod,
-    0, //sys_chmod,
+    sys_chmod,
 
-    0, //sys_chown,
+    sys_chown,
     0, //sys_break,
     0, //sys_stat,
     0, //sys_lseek,
@@ -157,7 +157,7 @@ fn_ptr sys_call_table[] = {
 
     0, //    sys_uname,
     0, //    sys_umask,
-    0, //    sys_chroot,
+    sys_chroot,
     0, //    sys_ustat,
     0, //    sys_dup2,
     sys_getppid,
-- 
Gitee