init: add an init_chdir helper

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 <hch@lst.de>

diff --git a/drivers/base/devtmpfs.c b/drivers/base/devtmpfs.c
index 32af6cb987b4287496c5df0738074de7b4ec4ea3..e48aaba3166b5d45e604658ac51e169a99d6a292 100644 (file)
--- a/drivers/base/devtmpfs.c
+++ b/drivers/base/devtmpfs.c
@@ -412,7 +412,7 @@ static int __init devtmpfs_setup(void *p)
        err = init_mount("devtmpfs", "/", "devtmpfs", MS_SILENT, NULL);
        if (err)
                goto out;
-       ksys_chdir("/.."); /* will traverse into overmounted root */
+       init_chdir("/.."); /* will traverse into overmounted root */
        ksys_chroot(".");
 out:
        *(int *)p = err;

diff --git a/fs/init.c b/fs/init.c
index eabd9ed2b51092cdaf54dca72946d9df1ea132d8..64d4e12eba933946f3330fee70d5650960e5bcb5 100644 (file)
--- a/fs/init.c
+++ b/fs/init.c
@@ -7,6 +7,7 @@
 #include <linux/mount.h>
 #include <linux/namei.h>
 #include <linux/fs.h>
+#include <linux/fs_struct.h>
 #include <linux/init_syscalls.h>
 #include "internal.h"
 
@@ -38,6 +39,21 @@ int __init init_umount(const char *name, int flags)
        return path_umount(&path, flags);
 }
 
+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));

diff --git a/fs/open.c b/fs/open.c
index b316dd6a86a8b9f270eed0e0d77c3fb969a2bc5d..723e0ac898935e0c3a1f14de3a974641d497a4a4 100644 (file)
--- 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 @@ out:
        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/init_syscalls.h b/include/linux/init_syscalls.h
index abf3af563c0b3aff1d1d46eb3c514846d1a3f2ee..1e845910ae56e9b50bc023e4b94738af60ab7539 100644 (file)
--- a/include/linux/init_syscalls.h
+++ b/include/linux/init_syscalls.h
@@ -3,5 +3,6 @@
 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_umount(const char *name, int flags);
+int __init init_chdir(const char *filename);
 int __init init_unlink(const char *pathname);
 int __init init_rmdir(const char *pathname);

diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index a7b14258d245e245664cb4810cf0816ed2f2dbd8..31fa67fb9894b32e403a997d3fe6906af4245863 100644 (file)
--- 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 83db87b6e5d1e0a056f7bf5f470768e8b542a942..a7581c6e85f2686ae5b1d6f8dd3113d93b42381e 100644 (file)
--- 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_initrd.c b/init/do_mounts_initrd.c
index 8b44dd017842a8929d7893a37b53eacae4ed6d0e..04627fd22a921fac08854c30b1fa0cf53a171648 100644 (file)
--- a/init/do_mounts_initrd.c
+++ b/init/do_mounts_initrd.c
@@ -61,7 +61,7 @@ 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();
@@ -82,7 +82,7 @@ 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
@@ -104,11 +104,11 @@ 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();