2014-01-21 13:58:22

by Florian Weimer

[permalink] [raw]
Subject: [PATCH 2/3] vfs: Implement fsetxattrat, fgetxattrat, flistxattrat, fremovexattrat

The implementation closely mirrors the existing fchownat system call.

Cc: Alexander Viro <[email protected]>
Signed-off-by: Florian Weimer <[email protected]>
---
fs/xattr.c | 122 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 122 insertions(+)

diff --git a/fs/xattr.c b/fs/xattr.c
index 9e44641..d626e42 100644
--- a/fs/xattr.c
+++ b/fs/xattr.c
@@ -434,6 +434,40 @@ SYSCALL_DEFINE5(fsetxattr, int, fd, const char __user *, name,
return error;
}

+SYSCALL_DEFINE6(fsetxattrat, int, fd, const char __user *, pathname,
+ const char __user *, name, const char __user *, value,
+ size_t, size, int, flags)
+{
+ struct path path;
+ int error;
+ unsigned int lookup_flags = 0;
+
+ if (flags & ~(XATTR_SET_MASK | AT_SYMLINK_NOFOLLOW | AT_EMPTY_PATH))
+ return -EINVAL;
+
+ if (!(flags & AT_SYMLINK_NOFOLLOW))
+ lookup_flags |= LOOKUP_FOLLOW;
+ if (flags & AT_EMPTY_PATH)
+ lookup_flags |= LOOKUP_EMPTY;
+
+retry:
+ error = user_path_at(fd, pathname, lookup_flags, &path);
+ if (error)
+ return error;
+ error = mnt_want_write(path.mnt);
+ if (!error) {
+ error = setxattr(path.dentry, name, value, size,
+ flags & XATTR_SET_MASK);
+ mnt_drop_write(path.mnt);
+ }
+ path_put(&path);
+ if (retry_estale(error, lookup_flags)) {
+ lookup_flags |= LOOKUP_REVAL;
+ goto retry;
+ }
+ return error;
+}
+
/*
* Extended attribute GET operations
*/
@@ -535,6 +569,35 @@ SYSCALL_DEFINE4(fgetxattr, int, fd, const char __user *, name,
return error;
}

+SYSCALL_DEFINE6(fgetxattrat, int, fd, const char __user *, pathname,
+ const char __user *, name, void __user *, value, size_t, size,
+ int, flags)
+{
+ struct path path;
+ ssize_t error;
+ unsigned int lookup_flags = 0;
+
+ if (flags & ~(AT_SYMLINK_NOFOLLOW | AT_EMPTY_PATH))
+ return -EINVAL;
+
+ if (!(flags & AT_SYMLINK_NOFOLLOW))
+ lookup_flags |= LOOKUP_FOLLOW;
+ if (flags & AT_EMPTY_PATH)
+ lookup_flags |= LOOKUP_EMPTY;
+
+retry:
+ error = user_path_at(fd, pathname, lookup_flags, &path);
+ if (error)
+ return error;
+ error = getxattr(path.dentry, name, value, size);
+ path_put(&path);
+ if (retry_estale(error, lookup_flags)) {
+ lookup_flags |= LOOKUP_REVAL;
+ goto retry;
+ }
+ return error;
+}
+
/*
* Extended attribute LIST operations
*/
@@ -624,6 +687,34 @@ SYSCALL_DEFINE3(flistxattr, int, fd, char __user *, list, size_t, size)
return error;
}

+SYSCALL_DEFINE5(flistxattrat, int, fd, const char __user *, pathname,
+ char __user *, list, size_t, size, int, flags)
+{
+ struct path path;
+ ssize_t error;
+ unsigned int lookup_flags = 0;
+
+ if (flags & ~(AT_SYMLINK_NOFOLLOW | AT_EMPTY_PATH))
+ return -EINVAL;
+
+ if (!(flags & AT_SYMLINK_NOFOLLOW))
+ lookup_flags |= LOOKUP_FOLLOW;
+ if (flags & AT_EMPTY_PATH)
+ lookup_flags |= LOOKUP_EMPTY;
+
+retry:
+ error = user_path_at(fd, pathname, lookup_flags, &path);
+ if (error)
+ return error;
+ error = listxattr(path.dentry, list, size);
+ path_put(&path);
+ if (retry_estale(error, lookup_flags)) {
+ lookup_flags |= LOOKUP_REVAL;
+ goto retry;
+ }
+ return error;
+}
+
/*
* Extended attribute REMOVE operations
*/
@@ -707,6 +798,37 @@ SYSCALL_DEFINE2(fremovexattr, int, fd, const char __user *, name)
return error;
}

+SYSCALL_DEFINE4(fremovexattrat, int, fd, const char __user *, pathname,
+ const char __user *, name, int, flags)
+{
+ struct path path;
+ int error;
+ unsigned int lookup_flags = 0;
+
+ if (flags & ~(AT_SYMLINK_NOFOLLOW | AT_EMPTY_PATH))
+ return -EINVAL;
+
+ if (!(flags & AT_SYMLINK_NOFOLLOW))
+ lookup_flags |= LOOKUP_FOLLOW;
+ if (flags & AT_EMPTY_PATH)
+ lookup_flags |= LOOKUP_EMPTY;
+
+retry:
+ error = user_path_at(fd, pathname, lookup_flags, &path);
+ if (error)
+ return error;
+ error = mnt_want_write(path.mnt);
+ if (!error) {
+ error = removexattr(path.dentry, name);
+ mnt_drop_write(path.mnt);
+ }
+ path_put(&path);
+ if (retry_estale(error, lookup_flags)) {
+ lookup_flags |= LOOKUP_REVAL;
+ goto retry;
+ }
+ return error;
+}

static const char *
strcmp_prefix(const char *a, const char *a_prefix)
--
1.8.3.1