From: Arnd Bergmann <arnd@arndb.de>
To: Aleksa Sarai <cyphar@cyphar.com>
Cc: linux-ia64@vger.kernel.org,
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Subject: Re: [PATCH v9 08/10] open: openat2(2) syscall
Date: Thu, 18 Jul 2019 17:10:21 +0200 [thread overview]
Message-ID: <CAK8P3a33rGhPDFfRBAQyLTMG_WoEgX_toDgWR2O7rSwxKsZG+w@mail.gmail.com> (raw)
In-Reply-To: <20190706145737.5299-9-cyphar@cyphar.com>
On Sat, Jul 6, 2019 at 5:00 PM Aleksa Sarai <cyphar@cyphar.com> wrote:
> diff --git a/arch/alpha/kernel/syscalls/syscall.tbl b/arch/alpha/kernel/syscalls/syscall.tbl
> index 9e7704e44f6d..1703d048c141 100644
> --- a/arch/alpha/kernel/syscalls/syscall.tbl
> +++ b/arch/alpha/kernel/syscalls/syscall.tbl
> @@ -461,6 +461,7 @@
> 530 common getegid sys_getegid
> 531 common geteuid sys_geteuid
> 532 common getppid sys_getppid
> +533 common openat2 sys_openat2
> # all other architectures have common numbers for new syscall, alpha
> # is the exception.
> 534 common pidfd_send_signal sys_pidfd_send_signal
My plan here was to add new syscalls in the same order as everwhere else,
just with the number 110 higher. In the long run, I hope we can automate
this.
> diff --git a/arch/arm/tools/syscall.tbl b/arch/arm/tools/syscall.tbl
> index aaf479a9e92d..4ad262698396 100644
> --- a/arch/arm/tools/syscall.tbl
> +++ b/arch/arm/tools/syscall.tbl
> @@ -447,3 +447,4 @@
> 431 common fsconfig sys_fsconfig
> 432 common fsmount sys_fsmount
> 433 common fspick sys_fspick
> +434 common openat2 sys_openat2
434 is already used in linux-next, I suggest you use 437 (Palmer
just submitted fchmodat4, which could become 436).
> +/**
> + * Arguments for how openat2(2) should open the target path. If @extra is zero,
> + * then openat2(2) is identical to openat(2).
> + *
> + * @flags: O_* flags (unknown flags ignored).
> + * @mode: O_CREAT file mode (ignored otherwise).
> + * @upgrade_mask: restrict how the O_PATH may be re-opened (ignored otherwise).
> + * @resolve: RESOLVE_* flags (-EINVAL on unknown flags).
> + * @reserved: reserved for future extensions, must be zeroed.
> + */
> +struct open_how {
> + __u32 flags;
> + union {
> + __u16 mode;
> + __u16 upgrade_mask;
> + };
> + __u16 resolve;
> + __u64 reserved[7]; /* must be zeroed */
> +};
We can have system calls with up to six arguments on all architectures, so
this could still be done more conventionally without the indirection: like
long openat2(int dfd, const char __user * filename, int flags, mode_t
mode_mask, __u16 resolve);
In fact, that seems similar enough to the existing openat() that I think
you could also just add the fifth argument to the existing call when
a newly defined flag is set, similarly to how we only use the 'mode'
argument when O_CREAT or O_TMPFILE are set.
> --- a/include/linux/syscalls.h
> +++ b/include/linux/syscalls.h
This file seems to lack a declaration for the system call, which means it
will cause a build failure on some architectures, e.g. arch/arc/kernel/sys.c:
#define __SYSCALL(nr, call) [nr] = (call),
void *sys_call_table[NR_syscalls] = {
[0 ... NR_syscalls-1] = sys_ni_syscall,
#include <asm/unistd.h>
};
Arnd
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next prev parent reply other threads:[~2019-07-18 15:10 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-06 14:57 [PATCH v9 00/10] namei: openat2(2) path resolution restrictions Aleksa Sarai
2019-07-06 14:57 ` [PATCH v9 01/10] namei: obey trailing magic-link DAC permissions Aleksa Sarai
2019-07-12 4:14 ` Al Viro
2019-07-12 6:36 ` Al Viro
2019-07-12 12:20 ` Aleksa Sarai
2019-07-12 13:10 ` Al Viro
2019-07-14 7:11 ` Aleksa Sarai
2019-07-06 14:57 ` [PATCH v9 02/10] procfs: switch magic-link modes to be more sane Aleksa Sarai
2019-07-06 14:57 ` [PATCH v9 03/10] open: O_EMPTYPATH: procfs-less file descriptor re-opening Aleksa Sarai
2019-07-06 14:57 ` [PATCH v9 04/10] namei: split out nd->dfd handling to dirfd_path_init Aleksa Sarai
2019-07-12 4:20 ` Al Viro
2019-07-12 12:07 ` Aleksa Sarai
2019-07-12 12:12 ` Aleksa Sarai
2019-07-06 14:57 ` [PATCH v9 05/10] namei: O_BENEATH-style path resolution flags Aleksa Sarai
2019-07-12 4:33 ` Al Viro
2019-07-12 10:57 ` Aleksa Sarai
2019-07-12 12:39 ` Al Viro
2019-07-12 12:55 ` Al Viro
2019-07-12 13:25 ` Al Viro
2019-07-12 15:00 ` Al Viro
2019-07-13 2:41 ` Al Viro
2019-07-14 3:58 ` Al Viro
2019-07-16 8:03 ` Aleksa Sarai
2019-07-14 7:00 ` Aleksa Sarai
2019-07-14 14:36 ` Al Viro
2019-07-18 3:17 ` Aleksa Sarai
2019-07-14 10:31 ` Aleksa Sarai
2019-07-06 14:57 ` [PATCH v9 06/10] namei: LOOKUP_IN_ROOT: chroot-like path resolution Aleksa Sarai
2019-07-06 14:57 ` [PATCH v9 07/10] namei: aggressively check for nd->root escape on ".." resolution Aleksa Sarai
2019-07-06 14:57 ` [PATCH v9 08/10] open: openat2(2) syscall Aleksa Sarai
2019-07-18 14:48 ` Rasmus Villemoes
2019-07-18 15:21 ` Aleksa Sarai
2019-07-18 15:10 ` Arnd Bergmann [this message]
2019-07-18 16:12 ` Aleksa Sarai
2019-07-18 21:29 ` Arnd Bergmann
2019-07-19 2:12 ` Dmitry V. Levin
2019-07-19 10:29 ` Christian Brauner
2019-07-19 1:59 ` Dmitry V. Levin
2019-07-19 2:19 ` Aleksa Sarai
2019-07-06 14:57 ` [PATCH v9 09/10] kselftest: save-and-restore errno to allow for %m formatting Aleksa Sarai
2019-07-06 14:57 ` [PATCH v9 10/10] selftests: add openat2(2) selftests Aleksa Sarai
2019-07-08 1:15 ` Michael Ellerman
2019-07-08 5:47 ` Aleksa Sarai
2019-07-12 15:11 ` [PATCH v9 00/10] namei: openat2(2) path resolution restrictions Al Viro
2019-07-12 15:32 ` Aleksa Sarai
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