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authorDominik Brodowski <linux@dominikbrodowski.net>2018-03-11 11:34:55 +0100
committerDominik Brodowski <linux@dominikbrodowski.net>2018-04-02 20:15:59 +0200
commit55731b3cda3a85ee888dac3bf1f36489f275c187 (patch)
treea322dc9efdd89932a35b294d221f90eccad45f23 /fs/open.c
parentcbfe20f565228966f0249f016752437df95df679 (diff)
fs: add do_fchownat(), ksys_fchown() helpers and ksys_{,l}chown() wrappers
Using the fs-interal do_fchownat() wrapper allows us to get rid of fs-internal calls to the sys_fchownat() syscall. Introducing the ksys_fchown() helper and the ksys_{,}chown() wrappers allows us to avoid the in-kernel calls to the sys_{,l,f}chown() syscalls. The ksys_ prefix denotes that these functions are meant as a drop-in replacement for the syscalls. In particular, they use the same calling convention as sys_{,l,f}chown(). This patch is part of a series which removes in-kernel calls to syscalls. On this basis, the syscall entry path can be streamlined. For details, see http://lkml.kernel.org/r/20180325162527.GA17492@light.dominikbrodowski.net Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
Diffstat (limited to 'fs/open.c')
-rw-r--r--fs/open.c23
1 files changed, 17 insertions, 6 deletions
diff --git a/fs/open.c b/fs/open.c
index 0fc8188be31a..7b2eccb541f2 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -645,8 +645,8 @@ retry_deleg:
return error;
}
-SYSCALL_DEFINE5(fchownat, int, dfd, const char __user *, filename, uid_t, user,
- gid_t, group, int, flag)
+int do_fchownat(int dfd, const char __user *filename, uid_t user, gid_t group,
+ int flag)
{
struct path path;
int error = -EINVAL;
@@ -677,18 +677,24 @@ out:
return error;
}
+SYSCALL_DEFINE5(fchownat, int, dfd, const char __user *, filename, uid_t, user,
+ gid_t, group, int, flag)
+{
+ return do_fchownat(dfd, filename, user, group, flag);
+}
+
SYSCALL_DEFINE3(chown, const char __user *, filename, uid_t, user, gid_t, group)
{
- return sys_fchownat(AT_FDCWD, filename, user, group, 0);
+ return do_fchownat(AT_FDCWD, filename, user, group, 0);
}
SYSCALL_DEFINE3(lchown, const char __user *, filename, uid_t, user, gid_t, group)
{
- return sys_fchownat(AT_FDCWD, filename, user, group,
- AT_SYMLINK_NOFOLLOW);
+ return do_fchownat(AT_FDCWD, filename, user, group,
+ AT_SYMLINK_NOFOLLOW);
}
-SYSCALL_DEFINE3(fchown, unsigned int, fd, uid_t, user, gid_t, group)
+int ksys_fchown(unsigned int fd, uid_t user, gid_t group)
{
struct fd f = fdget(fd);
int error = -EBADF;
@@ -708,6 +714,11 @@ out:
return error;
}
+SYSCALL_DEFINE3(fchown, unsigned int, fd, uid_t, user, gid_t, group)
+{
+ return ksys_fchown(fd, user, group);
+}
+
int open_check_o_direct(struct file *f)
{
/* NB: we're sure to have correct a_ops only after f_op->open */