This is nothing but making is possible to call the sys_close from the kernel.
Signed-off-by: Pavel Emelyanov <xemul@xxxxxxxxxxxxx>
---
fs/open.c | 32 ++++++++++++++++++++------------
include/linux/fs.h | 1 +
2 files changed, 21 insertions(+), 12 deletions(-)
diff --git a/fs/open.c b/fs/open.c
index b52cf01..126aa8b 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -1078,17 +1078,11 @@ int filp_close(struct file *filp, fl_owner_t id)
EXPORT_SYMBOL(filp_close);
-/*
- * Careful here! We test whether the file pointer is NULL before
- * releasing the fd. This ensures that one clone task can't release
- * an fd while another clone is opening it.
- */
-SYSCALL_DEFINE1(close, unsigned int, fd)
+int do_close(unsigned int fd)
{
struct file * filp;
struct files_struct *files = current->files;
struct fdtable *fdt;
- int retval;
spin_lock(&files->file_lock);
fdt = files_fdtable(files);
@@ -1101,7 +1095,25 @@ SYSCALL_DEFINE1(close, unsigned int, fd)
FD_CLR(fd, fdt->close_on_exec);
__put_unused_fd(files, fd);
spin_unlock(&files->file_lock);
- retval = filp_close(filp, files);
+
+ return filp_close(filp, files);
+
+out_unlock:
+ spin_unlock(&files->file_lock);
+ return -EBADF;
+}
+EXPORT_SYMBOL_GPL(do_close);
+
+/*
+ * Careful here! We test whether the file pointer is NULL before
+ * releasing the fd. This ensures that one clone task can't release
+ * an fd while another clone is opening it.
+ */
+SYSCALL_DEFINE1(close, unsigned int, fd)
+{
+ int retval;
+
+ retval = do_close(fd);
/* can't restart close syscall because file table entry was cleared */
if (unlikely(retval == -ERESTARTSYS ||
@@ -1111,10 +1123,6 @@ SYSCALL_DEFINE1(close, unsigned int, fd)
retval = -EINTR;
return retval;
-
-out_unlock:
- spin_unlock(&files->file_lock);
- return -EBADF;
}
EXPORT_SYMBOL(sys_close);
diff --git a/include/linux/fs.h b/include/linux/fs.h
index cdf9495..77a5d3e 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1991,6 +1991,7 @@ extern struct file *file_open_root(struct dentry *, struct vfsmount *,
extern struct file * dentry_open(struct dentry *, struct vfsmount *, int,
const struct cred *);
extern int filp_close(struct file *, fl_owner_t id);
+extern int do_close(unsigned int fd);
extern char * getname(const char __user *);
/* fs/ioctl.c */
--
1.5.5.6
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