From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752992AbeC2LlE (ORCPT ); Thu, 29 Mar 2018 07:41:04 -0400 Received: from isilmar-4.linta.de ([136.243.71.142]:59008 "EHLO isilmar-4.linta.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752867AbeC2L0U (ORCPT ); Thu, 29 Mar 2018 07:26:20 -0400 From: Dominik Brodowski To: linux-kernel@vger.kernel.org Cc: viro@ZenIV.linux.org.uk, torvalds@linux-foundation.org, arnd@arndb.de, linux-arch@vger.kernel.org, Al Viro Subject: [PATCH 091/109] kernel: add ksys_setsid() helper; remove in-kernel call to sys_setsid() Date: Thu, 29 Mar 2018 13:24:08 +0200 Message-Id: <20180329112426.23043-92-linux@dominikbrodowski.net> X-Mailer: git-send-email 2.16.3 In-Reply-To: <20180329112426.23043-1-linux@dominikbrodowski.net> References: <20180329112426.23043-1-linux@dominikbrodowski.net> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Using this helper allows us to avoid the in-kernel call to the sys_setsid() syscall. The ksys_ prefix denotes that this function is meant as a drop-in replacement for the syscall. In particular, it uses the same calling convention as sys_setsid(). 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 Signed-off-by: Dominik Brodowski --- include/linux/syscalls.h | 1 + init/do_mounts_initrd.c | 2 +- kernel/sys.c | 7 ++++++- 3 files changed, 8 insertions(+), 2 deletions(-) diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h index e724dda509e0..4dd685ee425d 100644 --- a/include/linux/syscalls.h +++ b/include/linux/syscalls.h @@ -962,6 +962,7 @@ off_t ksys_lseek(unsigned int fd, off_t offset, unsigned int whence); ssize_t ksys_read(unsigned int fd, char __user *buf, size_t count); void ksys_sync(void); int ksys_unshare(unsigned long unshare_flags); +int ksys_setsid(void); /* * The following kernel syscall equivalents are just wrappers to fs-internal diff --git a/init/do_mounts_initrd.c b/init/do_mounts_initrd.c index d1d3e53bdeef..5a91aefa7305 100644 --- a/init/do_mounts_initrd.c +++ b/init/do_mounts_initrd.c @@ -45,7 +45,7 @@ static int init_linuxrc(struct subprocess_info *info, struct cred *new) ksys_chdir("/root"); ksys_mount(".", "/", NULL, MS_MOVE, NULL); ksys_chroot("."); - sys_setsid(); + ksys_setsid(); return 0; } diff --git a/kernel/sys.c b/kernel/sys.c index 550f47788ae4..ad692183dfe9 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -1150,7 +1150,7 @@ static void set_special_pids(struct pid *pid) change_pid(curr, PIDTYPE_PGID, pid); } -SYSCALL_DEFINE0(setsid) +int ksys_setsid(void) { struct task_struct *group_leader = current->group_leader; struct pid *sid = task_pid(group_leader); @@ -1183,6 +1183,11 @@ SYSCALL_DEFINE0(setsid) return err; } +SYSCALL_DEFINE0(setsid) +{ + return ksys_setsid(); +} + DECLARE_RWSEM(uts_sem); #ifdef COMPAT_UTS_MACHINE -- 2.16.3