From a07b20004793d8926f78d63eb5980559f7813404 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Mon, 5 Nov 2018 17:40:30 +0000 Subject: vfs: syscall: Add open_tree(2) to reference or clone a mount open_tree(dfd, pathname, flags) Returns an O_PATH-opened file descriptor or an error. dfd and pathname specify the location to open, in usual fashion (see e.g. fstatat(2)). flags should be an OR of some of the following: * AT_PATH_EMPTY, AT_NO_AUTOMOUNT, AT_SYMLINK_NOFOLLOW - same meanings as usual * OPEN_TREE_CLOEXEC - make the resulting descriptor close-on-exec * OPEN_TREE_CLONE or OPEN_TREE_CLONE | AT_RECURSIVE - instead of opening the location in question, create a detached mount tree matching the subtree rooted at location specified by dfd/pathname. With AT_RECURSIVE the entire subtree is cloned, without it - only the part within in the mount containing the location in question. In other words, the same as mount --rbind or mount --bind would've taken. The detached tree will be dissolved on the final close of obtained file. Creation of such detached trees requires the same capabilities as doing mount --bind. Signed-off-by: Al Viro Signed-off-by: David Howells cc: linux-api@vger.kernel.org Signed-off-by: Al Viro --- arch/x86/entry/syscalls/syscall_32.tbl | 3 ++- arch/x86/entry/syscalls/syscall_64.tbl | 1 + 2 files changed, 3 insertions(+), 1 deletion(-) (limited to 'arch/x86/entry/syscalls') diff --git a/arch/x86/entry/syscalls/syscall_32.tbl b/arch/x86/entry/syscalls/syscall_32.tbl index 1f9607ed087c..ae2294d07ecb 100644 --- a/arch/x86/entry/syscalls/syscall_32.tbl +++ b/arch/x86/entry/syscalls/syscall_32.tbl @@ -398,7 +398,8 @@ 384 i386 arch_prctl sys_arch_prctl __ia32_compat_sys_arch_prctl 385 i386 io_pgetevents sys_io_pgetevents_time32 __ia32_compat_sys_io_pgetevents 386 i386 rseq sys_rseq __ia32_sys_rseq -# don't use numbers 387 through 392, add new calls at the end +387 i386 open_tree sys_open_tree __ia32_sys_open_tree +# don't use numbers 388 through 392, add new calls at the end 393 i386 semget sys_semget __ia32_sys_semget 394 i386 semctl sys_semctl __ia32_compat_sys_semctl 395 i386 shmget sys_shmget __ia32_sys_shmget diff --git a/arch/x86/entry/syscalls/syscall_64.tbl b/arch/x86/entry/syscalls/syscall_64.tbl index 92ee0b4378d4..a6e06c35b5b1 100644 --- a/arch/x86/entry/syscalls/syscall_64.tbl +++ b/arch/x86/entry/syscalls/syscall_64.tbl @@ -343,6 +343,7 @@ 332 common statx __x64_sys_statx 333 common io_pgetevents __x64_sys_io_pgetevents 334 common rseq __x64_sys_rseq +335 common open_tree __x64_sys_open_tree # don't use numbers 387 through 423, add new calls after the last # 'common' entry 424 common pidfd_send_signal __x64_sys_pidfd_send_signal -- cgit v1.2.3