1 files changed, 39 insertions, 5 deletions

diff --git a/sys/kern/vfs_syscalls.c b/sys/kern/vfs_syscalls.c
index 990d722..0d51331 100644
--- a/sys/kern/vfs_syscalls.c
+++ b/sys/kern/vfs_syscalls.c
@@ -43,7 +43,7 @@ static int
 vfs_dostat(const char *path, struct stat *sbuf)
 {
     char pathbuf[PATH_MAX];
-    struct vattr *attr;
+    struct vattr attr;
     struct stat st;
     struct vnode *vp;
     struct vop_getattr_args gattr;
@@ -58,7 +58,7 @@ vfs_dostat(const char *path, struct stat *sbuf)
         return -EFAULT;
     }
 
-    nd.path = path;
+    nd.path = pathbuf;
     nd.flags = 0;
 
     if ((error = namei(&nd)) != 0) {
@@ -67,19 +67,42 @@ vfs_dostat(const char *path, struct stat *sbuf)
 
     vp = nd.vp;
     gattr.vp = vp;
+    gattr.res = &attr;
     error = vfs_vop_getattr(vp, &gattr);
 
     if (error != 0) {
         return error;
     }
 
-    attr = gattr.res;
     memset(&st, VNOVAL, sizeof(st));
 
     /* Copy stat data to userspace statbuf */
-    st.st_mode = attr->mode;
-    st.st_size = attr->size;
+    st.st_mode = attr.mode;
+    st.st_size = attr.size;
     copyout(&st, sbuf, sizeof(*sbuf));
+    vfs_release_vnode(vp);
+    return 0;
+}
+
+static int
+vfs_doaccess(const char *path)
+{
+    struct nameidata nd;
+    char pathbuf[PATH_MAX];
+    int error;
+
+    if ((copyinstr(path, pathbuf, sizeof(pathbuf))) < 0) {
+        return -EFAULT;
+    }
+
+    nd.path = pathbuf;
+    nd.flags = 0;
+
+    if ((error = namei(&nd)) != 0) {
+        return error;
+    }
+
+    vfs_release_vnode(nd.vp);
     return 0;
 }
 
@@ -149,3 +172,14 @@ sys_stat(struct syscall_args *scargs)
 {
     return vfs_dostat((const char *)scargs->arg0, (void *)scargs->arg1);
 }
+
+/*
+ * Check if a file can be accessed.
+ *
+ * @arg0: path
+ */
+scret_t
+sys_access(struct syscall_args *scargs)
+{
+    return vfs_doaccess((const char *)scargs->arg0);
+}