Hi,
Le 06/06/2022 à 15:44, Adhemerval Zanella via Libc-alpha a écrit :
It was added on Linux 5.12 (2a1867219c7b27f928e2545782b86daaf9ad50bd)
to allow change the properties of a mount or a mount tree using file
descriptors which the new mount api is based on.
Checked on x86_64-linux-gnu.
---
NEWS | 6 ++--
sysdeps/unix/sysv/linux/Versions | 1 +
sysdeps/unix/sysv/linux/aarch64/libc.abilist | 1 +
sysdeps/unix/sysv/linux/alpha/libc.abilist | 1 +
sysdeps/unix/sysv/linux/arc/libc.abilist | 1 +
sysdeps/unix/sysv/linux/arm/be/libc.abilist | 1 +
sysdeps/unix/sysv/linux/arm/le/libc.abilist | 1 +
sysdeps/unix/sysv/linux/csky/libc.abilist | 1 +
sysdeps/unix/sysv/linux/hppa/libc.abilist | 1 +
sysdeps/unix/sysv/linux/i386/libc.abilist | 1 +
sysdeps/unix/sysv/linux/ia64/libc.abilist | 1 +
.../sysv/linux/m68k/coldfire/libc.abilist | 1 +
.../unix/sysv/linux/m68k/m680x0/libc.abilist | 1 +
.../sysv/linux/microblaze/be/libc.abilist | 1 +
.../sysv/linux/microblaze/le/libc.abilist | 1 +
.../sysv/linux/mips/mips32/fpu/libc.abilist | 1 +
.../sysv/linux/mips/mips32/nofpu/libc.abilist | 1 +
.../sysv/linux/mips/mips64/n32/libc.abilist | 1 +
.../sysv/linux/mips/mips64/n64/libc.abilist | 1 +
sysdeps/unix/sysv/linux/nios2/libc.abilist | 1 +
sysdeps/unix/sysv/linux/or1k/libc.abilist | 1 +
.../linux/powerpc/powerpc32/fpu/libc.abilist | 1 +
.../powerpc/powerpc32/nofpu/libc.abilist | 1 +
.../linux/powerpc/powerpc64/be/libc.abilist | 1 +
.../linux/powerpc/powerpc64/le/libc.abilist | 1 +
.../unix/sysv/linux/riscv/rv32/libc.abilist | 1 +
.../unix/sysv/linux/riscv/rv64/libc.abilist | 1 +
.../unix/sysv/linux/s390/s390-32/libc.abilist | 1 +
.../unix/sysv/linux/s390/s390-64/libc.abilist | 1 +
sysdeps/unix/sysv/linux/sh/be/libc.abilist | 1 +
sysdeps/unix/sysv/linux/sh/le/libc.abilist | 1 +
.../sysv/linux/sparc/sparc32/libc.abilist | 1 +
.../sysv/linux/sparc/sparc64/libc.abilist | 1 +
sysdeps/unix/sysv/linux/sys/mount.h | 22 ++++++++++++++
sysdeps/unix/sysv/linux/syscalls.list | 1 +
sysdeps/unix/sysv/linux/tst-mount.c | 30 +++++++++++++++++--
.../unix/sysv/linux/x86_64/64/libc.abilist | 1 +
.../unix/sysv/linux/x86_64/x32/libc.abilist | 1 +
38 files changed, 87 insertions(+), 6 deletions(-)
diff --git a/NEWS b/NEWS
index de12657449..696de3962b 100644
--- a/NEWS
+++ b/NEWS
@@ -29,9 +29,9 @@ Major new features:
memory is carried out in the context of the caller, using the caller's
CPU affinity, and priority with CPU usage accounted to the caller.
-* On Linux, the fsopen, fsmount, move_mount, fsconfig, fspick, and open_tree
- have been added. It is a new mount API to allow more flexibility on mount
- operations, specially when used along namespaces.
+* On Linux, the fsopen, fsmount, move_mount, fsconfig, fspick, open_tree,
+ and mount_setattr have been added. It is a new mount API to allow more
+ flexibility on mount operations, specially when used along namespaces.
Deprecated and removed features, and other changes affecting compatibility:
diff --git a/sysdeps/unix/sysv/linux/Versions b/sysdeps/unix/sysv/linux/Versions
index b70530ef40..65d2ceda2c 100644
--- a/sysdeps/unix/sysv/linux/Versions
+++ b/sysdeps/unix/sysv/linux/Versions
@@ -305,6 +305,7 @@ libc {
fsopen;
fspick;
move_mount;
+ mount_setattr;
open_tree;
pidfd_open;
pidfd_getfd;
diff --git a/sysdeps/unix/sysv/linux/sys/mount.h b/sysdeps/unix/sysv/linux/sys/mount.h
index eb6705a091..4929d84027 100644
--- a/sysdeps/unix/sysv/linux/sys/mount.h
+++ b/sysdeps/unix/sysv/linux/sys/mount.h
@@ -23,6 +23,8 @@
#include <fcntl.h>
#include <features.h>
+#include <stdint.h>
+#include <stddef.h>
#include <sys/ioctl.h>
#define BLOCK_SIZE 1024
@@ -155,6 +157,17 @@ enum
#define MOUNT_ATTR_NOSYMFOLLOW 0x00200000 /* Do not follow symlinks. */
+/* For mount_setattr. */
+struct mount_attr
+{
+ uint64_t attr_set;
+ uint64_t attr_clr;
+ uint64_t propagation;
+ uint64_t userns_fd;
+};
+
+#define MOUNT_ATTR_SIZE_VER0 32 /* sizeof first published struct */
+
/* move_mount flags. */
#define MOVE_MOUNT_F_SYMLINKS 0x00000001 /* Follow symlinks on from path */
#define MOVE_MOUNT_F_AUTOMOUNTS 0x00000002 /* Follow automounts on from path */
@@ -240,6 +253,15 @@ extern int fspick (int __dfd, const char *__path, unsigned int __flags)
extern int open_tree (int __dfd, const char *__filename, unsigned int __flags)
__THROW;
+/* Change the mount proprieties of the mount or an entire mount tree. If
+ PATH is a relative pathname, then it is interpreted relative to the directory
+ referred to by the file descriptor dirfd. Otherwise if DFD is the special
+ value AT_FDCWD then PATH is interpreted relative to the current working
+ directory of the calling process. */
+extern int mount_setattr (int __dfd, const char *__path, unsigned int __flags,
+ struct mount_attr *__uattr, size_t __usize)
+ __THROW;
+
I wonder why __uattr is not declared const struct mount_attr * ?
Is it really expected that future mount_setattr() extensions to write
back into the userspace structure ?
__END_DECLS
#endif /* _SYS_MOUNT_H */
diff --git a/sysdeps/unix/sysv/linux/syscalls.list b/sysdeps/unix/sysv/linux/syscalls.list
index e5e2b528fd..f79a519d89 100644
--- a/sysdeps/unix/sysv/linux/syscalls.list
+++ b/sysdeps/unix/sysv/linux/syscalls.list
@@ -39,6 +39,7 @@ mincore - mincore i:aUV mincore
mlock - mlock i:bU mlock
mlockall - mlockall i:i mlockall
mount EXTRA mount i:sssUp __mount mount
+mount_setattr EXTRA mount_setattr i:isUpi mount_setattr
move_mount EXTRA move_mount i:isisU move_mount
munlock - munlock i:aU munlock
munlockall - munlockall i: munlockall
Regards
--
Yann Droneaud
OPTEYA
