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authorAl Viro <viro@zeniv.linux.org.uk>2009-03-30 07:20:30 -0400
committerAl Viro <viro@zeniv.linux.org.uk>2009-03-31 23:00:26 -0400
commit498052bba55ecaff58db6a1436b0e25bfd75a7ff (patch)
treebd3644ac60737e3733995a203acebd70cfd1b21b /include/linux/fs_struct.h
parent3e93cd671813e204c258f1e6c797959920cf7772 (diff)
downloadvexpress-lsk-498052bba55ecaff58db6a1436b0e25bfd75a7ff.tar.gz
New locking/refcounting for fs_struct
* all changes of current->fs are done under task_lock and write_lock of old fs->lock * refcount is not atomic anymore (same protection) * its decrements are done when removing reference from current; at the same time we decide whether to free it. * put_fs_struct() is gone * new field - ->in_exec. Set by check_unsafe_exec() if we are trying to do execve() and only subthreads share fs_struct. Cleared when finishing exec (success and failure alike). Makes CLONE_FS fail with -EAGAIN if set. * check_unsafe_exec() may fail with -EAGAIN if another execve() from subthread is in progress. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'include/linux/fs_struct.h')
-rw-r--r--include/linux/fs_struct.h8
1 files changed, 3 insertions, 5 deletions
diff --git a/include/linux/fs_struct.h b/include/linux/fs_struct.h
index 298cef1c079..78a05bfcd8e 100644
--- a/include/linux/fs_struct.h
+++ b/include/linux/fs_struct.h
@@ -4,12 +4,10 @@
#include <linux/path.h>
struct fs_struct {
- atomic_t count; /* This usage count is used by check_unsafe_exec() for
- * security checking purposes - therefore it may not be
- * incremented, except by clone(CLONE_FS).
- */
+ int users;
rwlock_t lock;
int umask;
+ int in_exec;
struct path root, pwd;
};
@@ -19,7 +17,7 @@ extern void exit_fs(struct task_struct *);
extern void set_fs_root(struct fs_struct *, struct path *);
extern void set_fs_pwd(struct fs_struct *, struct path *);
extern struct fs_struct *copy_fs_struct(struct fs_struct *);
-extern void put_fs_struct(struct fs_struct *);
+extern void free_fs_struct(struct fs_struct *);
extern void daemonize_fs_struct(void);
extern int unshare_fs_struct(void);