[PATCH 16/24] fs: add a kern_symlink helper
From: Christoph Hellwig <hch@lst.de>
Date: 2020-07-20 16:27:48
Also in:
linux-fsdevel, linux-raid, lkml
Subsystem:
abi/api, filesystems (vfs and infrastructure), the rest · Maintainers:
Alexander Viro, Christian Brauner, Linus Torvalds
Add a simple helper perform a symlink with a kernel space file name and use it in the early init code instead of relying on the implicit set_fs(KERNEL_DS) there. To do so push the getname from do_symlinkat into the callers. Remove the now unused ksys_symlink. Signed-off-by: Christoph Hellwig <hch@lst.de> --- fs/internal.h | 2 -- fs/namei.c | 27 ++++++++++++++++++--------- include/linux/fs.h | 1 + include/linux/syscalls.h | 9 --------- init/initramfs.c | 2 +- 5 files changed, 20 insertions(+), 21 deletions(-)
diff --git a/fs/internal.h b/fs/internal.h
index f0869d5dc4dbfa..46f727c0bd84e2 100644
--- a/fs/internal.h
+++ b/fs/internal.h@@ -64,8 +64,6 @@ extern int vfs_path_lookup(struct dentry *, struct vfsmount *, const char *, unsigned int, struct path *); long do_rmdir(int dfd, const char __user *pathname); long do_unlinkat(int dfd, struct filename *name); -long do_symlinkat(const char __user *oldname, int newdfd, - const char __user *newname); /* * namespace.c
diff --git a/fs/namei.c b/fs/namei.c
index 9d80a5bce1051a..01e43676008644 100644
--- a/fs/namei.c
+++ b/fs/namei.c@@ -3991,20 +3991,21 @@ int vfs_symlink(struct inode *dir, struct dentry *dentry, const char *oldname) } EXPORT_SYMBOL(vfs_symlink); -long do_symlinkat(const char __user *oldname, int newdfd, - const char __user *newname) +static int do_symlinkat(struct filename *from, int newdfd, + struct filename *newname) { int error; - struct filename *from; struct dentry *dentry; struct path path; unsigned int lookup_flags = 0; - from = getname(oldname); - if (IS_ERR(from)) + if (IS_ERR(from)) { + if (!IS_ERR(newname)) + putname(newname); return PTR_ERR(from); + } retry: - dentry = user_path_create(newdfd, newname, &path, lookup_flags); + dentry = filename_create(newdfd, newname, &path, lookup_flags); error = PTR_ERR(dentry); if (IS_ERR(dentry)) goto out_putname;
@@ -4017,20 +4018,28 @@ long do_symlinkat(const char __user *oldname, int newdfd, lookup_flags |= LOOKUP_REVAL; goto retry; } + putname(newname); out_putname: - putname(from); + if (!IS_ERR(from)) + putname(from); return error; } +int __init kern_symlink(const char *oldname, const char *newname) +{ + return do_symlinkat(getname_kernel(oldname), AT_FDCWD, + getname_kernel(newname)); +} + SYSCALL_DEFINE3(symlinkat, const char __user *, oldname, int, newdfd, const char __user *, newname) { - return do_symlinkat(oldname, newdfd, newname); + return do_symlinkat(getname(oldname), newdfd, getname(newname)); } SYSCALL_DEFINE2(symlink, const char __user *, oldname, const char __user *, newname) { - return do_symlinkat(oldname, AT_FDCWD, newname); + return do_symlinkat(getname(oldname), AT_FDCWD, getname(newname)); } /**
diff --git a/include/linux/fs.h b/include/linux/fs.h
index fc3b09d473945f..7a7b3bf1b8aa53 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h@@ -3680,5 +3680,6 @@ int __init kern_utimes(const char *filename, struct timespec64 *tv, int flags); int kern_mkdir(const char *pathname, umode_t mode); int kern_mknod(const char *filename, umode_t mode, unsigned int dev); int __init kern_link(const char *oldname, const char *newname); +int __init kern_symlink(const char *oldname, const char *newname); #endif /* _LINUX_FS_H */
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 467cc4413874ed..474d5d165048c8 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h@@ -1284,15 +1284,6 @@ static inline long ksys_rmdir(const char __user *pathname) return do_rmdir(AT_FDCWD, pathname); } -extern long do_symlinkat(const char __user *oldname, int newdfd, - const char __user *newname); - -static inline long ksys_symlink(const char __user *oldname, - const char __user *newname) -{ - return do_symlinkat(oldname, AT_FDCWD, newname); -} - extern long do_sys_ftruncate(unsigned int fd, loff_t length, int small); static inline long ksys_ftruncate(unsigned int fd, loff_t length)
diff --git a/init/initramfs.c b/init/initramfs.c
index e484381c6c131b..4efd78427996da 100644
--- a/init/initramfs.c
+++ b/init/initramfs.c@@ -389,7 +389,7 @@ static int __init do_symlink(void) { collected[N_ALIGN(name_len) + body_len] = '\0'; clean_path(collected, 0); - ksys_symlink(collected + N_ALIGN(name_len), collected); + kern_symlink(collected + N_ALIGN(name_len), collected); kern_chown(collected, uid, gid, AT_SYMLINK_NOFOLLOW); do_utime(collected, mtime); state = SkipIt;
--
2.27.0