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authorChristoph Hellwig <hch@lst.de>2020-07-22 11:25:21 +0200
committerChristoph Hellwig <hch@lst.de>2020-07-31 08:17:52 +0200
commitdb63f1e315384590b979f8f74abd1b5363b69894 (patch)
tree5bcaeab28afa531c24c028f1b40e8d4cadd9ce53
parent20cce026c3e0972017b9cb4a7cccfb8cacf187d5 (diff)
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>
-rw-r--r--drivers/base/devtmpfs.c2
-rw-r--r--fs/init.c16
-rw-r--r--fs/open.c7
-rw-r--r--include/linux/init_syscalls.h1
-rw-r--r--include/linux/syscalls.h1
-rw-r--r--init/do_mounts.c2
-rw-r--r--init/do_mounts_initrd.c8
7 files changed, 24 insertions, 13 deletions
diff --git a/drivers/base/devtmpfs.c b/drivers/base/devtmpfs.c
index 32af6cb987b4..e48aaba3166b 100644
--- 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 eabd9ed2b510..64d4e12eba93 100644
--- 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 b316dd6a86a8..723e0ac89893 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 @@ 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 abf3af563c0b..1e845910ae56 100644
--- 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 a7b14258d245..31fa67fb9894 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 83db87b6e5d1..a7581c6e85f2 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_initrd.c b/init/do_mounts_initrd.c
index 8b44dd017842..04627fd22a92 100644
--- 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();