From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoph Hellwig Subject: [PATCH 15/24] init: add an init_chdir helper Date: Tue, 21 Jul 2020 18:28:09 +0200 Message-ID: <20200721162818.197315-16-hch@lst.de> References: <20200721162818.197315-1-hch@lst.de> Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: <20200721162818.197315-1-hch@lst.de> Sender: linux-raid-owner@vger.kernel.org To: Al Viro , Linus Torvalds Cc: Greg Kroah-Hartman , "Rafael J. Wysocki" , linux-kernel@vger.kernel.org, linux-raid@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-api@vger.kernel.org List-Id: linux-raid.ids Add a simple helper to chdir with a kernel space file name and switch the early init code over to it. Remove the now unused ksys_chdir. Signed-off-by: Christoph Hellwig --- fs/open.c | 7 +------ include/linux/syscalls.h | 1 - init/do_mounts.c | 2 +- init/do_mounts.h | 1 + init/do_mounts_initrd.c | 8 ++++---- init/fs.c | 16 ++++++++++++++++ 6 files changed, 23 insertions(+), 12 deletions(-) diff --git a/fs/open.c b/fs/open.c index b316dd6a86a8b9..723e0ac898935e 100644 --- a/fs/open.c +++ b/fs/open.c @@ -482,7 +482,7 @@ SYSCALL_DEFINE2(access, const char __user *, filename, int, mode) return do_faccessat(AT_FDCWD, filename, mode, 0); } -int ksys_chdir(const char __user *filename) +SYSCALL_DEFINE1(chdir, const char __user *, filename) { struct path path; int error; @@ -508,11 +508,6 @@ int ksys_chdir(const char __user *filename) return error; } -SYSCALL_DEFINE1(chdir, const char __user *, filename) -{ - return ksys_chdir(filename); -} - SYSCALL_DEFINE1(fchdir, unsigned int, fd) { struct fd f = fdget_raw(fd); diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h index a7b14258d245e2..31fa67fb9894b3 100644 --- a/include/linux/syscalls.h +++ b/include/linux/syscalls.h @@ -1238,7 +1238,6 @@ asmlinkage long sys_ni_syscall(void); int ksys_chroot(const char __user *filename); ssize_t ksys_write(unsigned int fd, const char __user *buf, size_t count); -int ksys_chdir(const char __user *filename); int ksys_fchown(unsigned int fd, uid_t user, gid_t group); ssize_t ksys_read(unsigned int fd, char __user *buf, size_t count); void ksys_sync(void); diff --git a/init/do_mounts.c b/init/do_mounts.c index 4812e21d149cab..cc08ed7b44e764 100644 --- a/init/do_mounts.c +++ b/init/do_mounts.c @@ -408,7 +408,7 @@ static int __init do_mount_root(const char *name, const char *fs, if (ret) goto out; - ksys_chdir("/root"); + init_chdir("/root"); s = current->fs->pwd.dentry->d_sb; ROOT_DEV = s->s_dev; printk(KERN_INFO diff --git a/init/do_mounts.h b/init/do_mounts.h index 58605396d358d7..c82fcb27575877 100644 --- a/init/do_mounts.h +++ b/init/do_mounts.h @@ -11,6 +11,7 @@ int __init init_mount(const char *dev_name, const char *dir_name, const char *type_page, unsigned long flags, void *data_page); +int __init init_chdir(const char *filename); int __init init_unlink(const char *pathname); int __init init_rmdir(const char *pathname); diff --git a/init/do_mounts_initrd.c b/init/do_mounts_initrd.c index dd4680c8ac762e..ef214a78e7ee49 100644 --- a/init/do_mounts_initrd.c +++ b/init/do_mounts_initrd.c @@ -62,7 +62,7 @@ static int __init init_linuxrc(struct subprocess_info *info, struct cred *new) ksys_unshare(CLONE_FS | CLONE_FILES); console_on_rootfs(); /* move initrd over / and chdir/chroot in initrd root */ - ksys_chdir("/root"); + init_chdir("/root"); init_mount(".", "/", NULL, MS_MOVE, NULL); ksys_chroot("."); ksys_setsid(); @@ -83,7 +83,7 @@ static void __init handle_initrd(void) /* mount initrd on rootfs' /root */ mount_block_root("/dev/root.old", root_mountflags & ~MS_RDONLY); ksys_mkdir("/old", 0700); - ksys_chdir("/old"); + init_chdir("/old"); /* * In case that a resume from disk is carried out by linuxrc or one of @@ -105,11 +105,11 @@ static void __init handle_initrd(void) ksys_chroot(".."); if (new_decode_dev(real_root_dev) == Root_RAM0) { - ksys_chdir("/old"); + init_chdir("/old"); return; } - ksys_chdir("/"); + init_chdir("/"); ROOT_DEV = new_decode_dev(real_root_dev); mount_root(); diff --git a/init/fs.c b/init/fs.c index b69b2f949b6132..f3d8da00662572 100644 --- a/init/fs.c +++ b/init/fs.c @@ -3,6 +3,7 @@ #include #include #include +#include #include <../fs/internal.h> #include "do_mounts.h" @@ -20,6 +21,21 @@ int __init init_mount(const char *dev_name, const char *dir_name, return ret; } +int __init init_chdir(const char *filename) +{ + struct path path; + int error; + + error = kern_path(filename, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, &path); + if (error) + return error; + error = inode_permission(path.dentry->d_inode, MAY_EXEC | MAY_CHDIR); + if (!error) + set_fs_pwd(current->fs, &path); + path_put(&path); + return error; +} + int __init init_unlink(const char *pathname) { return do_unlinkat(AT_FDCWD, getname_kernel(pathname)); -- 2.27.0