From patchwork Wed Jul 17 01:27:17 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Palmer Dabbelt X-Patchwork-Id: 1133052 Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 45pL7f444rz9s7T for ; Wed, 17 Jul 2019 12:00:14 +1000 (AEST) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=sifive.com Authentication-Results: ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=sifive.com header.i=@sifive.com header.b="DLAJM7oG"; dkim-atps=neutral Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 45pL7f34JLzDqLN for ; Wed, 17 Jul 2019 12:00:14 +1000 (AEST) X-Original-To: linuxppc-dev@lists.ozlabs.org Delivered-To: linuxppc-dev@lists.ozlabs.org Authentication-Results: lists.ozlabs.org; spf=pass (mailfrom) smtp.mailfrom=sifive.com (client-ip=2607:f8b0:4864:20::642; helo=mail-pl1-x642.google.com; envelope-from=palmer@sifive.com; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=sifive.com Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=sifive.com header.i=@sifive.com header.b="DLAJM7oG"; dkim-atps=neutral Received: from mail-pl1-x642.google.com (mail-pl1-x642.google.com [IPv6:2607:f8b0:4864:20::642]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 45pKRx4sFMzDqWN for ; Wed, 17 Jul 2019 11:29:17 +1000 (AEST) Received: by mail-pl1-x642.google.com with SMTP id c14so11018619plo.0 for ; Tue, 16 Jul 2019 18:29:17 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sifive.com; s=google; h=subject:date:message-id:in-reply-to:references:mime-version :content-transfer-encoding:cc:from:to; bh=Km6i2EwlnHTMsEa+Chc8B8lkJXrzGe+ncWgEI0oBDH8=; b=DLAJM7oG3ybeUmclWPVZfMhBUnRrw9wGMdXduIn2giXhaGrJ7S5W8yVcEE2KwLFQAh D1fm8Qfvlg4+vU/wK9eEo2SBWGFnrW2QH4msqzaJa2F5Mqtk545ueU4VzXlO2Pka91aE 0ZIjIFL3MsFSMfhP6hasIsWi+LC5nQsPKwISrpKwFjetWndP1gu0y7RwT7xlLsYYY3bX aA9+vRQ2Jy/EGfc2fUemHwW+nDNJKVxhk9EQMc/dKQv4LICHm3AoRl9JnxONdNyJNxBk BKPc4PBCTZeLcTJbqW33HPUobtx12bsfbsrHt2Ek4XDY+qdDSWFBlI6LBq/1RrDbWAwT fAfQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding:cc:from:to; bh=Km6i2EwlnHTMsEa+Chc8B8lkJXrzGe+ncWgEI0oBDH8=; b=B+gCeaCYolVVY+StFSgUNtluAcNZIb5X664vQqPIN983D/pMTnAMwy8aBEBV6t8rA7 SQMLY4qFOMyOf4GY2numWoh5gEMNmWJT0nD2+pV8q/SKyXyJ5H4g7RMcAWIs3fbR2WCr cMFsW9lx6kHXKQ3zLl12wc+FfWRwRM4+nXVP4KT6sX3+vhN4DraDqHbg9YUXLDuc5YiQ EMRykDRUkLe4Dy3VkPA0FT5giLV7Kl8fysIZfQWPABqTU45wYm2E60vUeA2k3XrCT2kX ib5l4sA6Xokok2/dvlCn4zv2OB9aSgdOY81KdTtUKprmrZFLrV9Be4z4sbIzRnAPQGNI iPlw== X-Gm-Message-State: APjAAAUOZCENPf/6ivVbzSYPPAQpAv/m5FJGugJvw2gBB3++UsbHFnzG L4nbRerWuEn2Y8pxya3zqf7oGA== X-Google-Smtp-Source: APXvYqy1hMVJ/bl9aSMVuTE5nvwz4oMGbsdCr+A6D4NXU76rmJy3i+4M2pUivduNcdb15I23YjfxXQ== X-Received: by 2002:a17:902:ba96:: with SMTP id k22mr40372539pls.44.1563326954956; Tue, 16 Jul 2019 18:29:14 -0700 (PDT) Received: from localhost ([12.206.222.5]) by smtp.gmail.com with ESMTPSA id s11sm20793710pgv.13.2019.07.16.18.29.13 (version=TLS1_3 cipher=AEAD-AES256-GCM-SHA384 bits=256/256); Tue, 16 Jul 2019 18:29:14 -0700 (PDT) Subject: [PATCH v2 2/4] Add fchmodat4(), a new syscall Date: Tue, 16 Jul 2019 18:27:17 -0700 Message-Id: <20190717012719.5524-3-palmer@sifive.com> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190717012719.5524-1-palmer@sifive.com> References: <20190717012719.5524-1-palmer@sifive.com> MIME-Version: 1.0 From: Palmer Dabbelt To: viro@zeniv.linux.org.uk, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-api@vger.kernel.org, Arnd Bergmann X-Mailman-Approved-At: Wed, 17 Jul 2019 11:58:47 +1000 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: dalias@libc.org, linux-ia64@vger.kernel.org, linux-sh@vger.kernel.org, peterz@infradead.org, Palmer Dabbelt , heiko.carstens@de.ibm.com, stefan@agner.ch, James.Bottomley@HansenPartnership.com, namhyung@kernel.org, kim.phillips@arm.com, paulus@samba.org, deepa.kernel@gmail.com, hpa@zytor.com, sparclinux@vger.kernel.org, will@kernel.org, linux-arch@vger.kernel.org, linux-s390@vger.kernel.org, hare@suse.com, Arnd Bergmann , ysato@users.sourceforge.jp, deller@gmx.de, x86@kernel.org, linux@armlinux.org.uk, borntraeger@de.ibm.com, mingo@redhat.com, geert@linux-m68k.org, linux-arm-kernel@lists.infradead.org, catalin.marinas@arm.com, jhogan@kernel.org, firoz.khan@linaro.org, mattst88@gmail.com, fenghua.yu@intel.com, gor@linux.ibm.com, jolsa@redhat.com, tycho@tycho.ws, acme@kernel.org, linux-m68k@lists.linux-m68k.org, ink@jurassic.park.msu.ru, luto@kernel.org, alexander.shishkin@linux.intel.com, tglx@linutronix.de, christian@brauner.io, rth@twiddle.net, axboe@kernel.dk, dhowells@redhat.com, monstr@monstr.eu, tony.luck@intel.com, linux-parisc@vger.kernel.org, linux-mips@vger.kernel.org, ralf@linux-mips.org, paul.burton@mips.com, linux-alpha@vger.kernel.org, schwidefsky@de.ibm.com, bp@alien8.de, linuxppc-dev@lists.ozlabs.org, davem@davemloft.net Errors-To: linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" man 3p says that fchmodat() takes a flags argument, but the Linux syscall does not. There doesn't appear to be a good userspace workaround for this issue but the implementation in the kernel is pretty straight-forward. The specific use case where the missing flags came up was WRT a fuse filesystem implemenation, but the functionality is pretty generic so I'm assuming there would be other use cases. Signed-off-by: Palmer Dabbelt --- fs/open.c | 20 ++++++++++++++++---- include/linux/syscalls.h | 7 +++++-- 2 files changed, 21 insertions(+), 6 deletions(-) diff --git a/fs/open.c b/fs/open.c index b5b80469b93d..2f72b4d6a2c1 100644 --- a/fs/open.c +++ b/fs/open.c @@ -569,11 +569,17 @@ SYSCALL_DEFINE2(fchmod, unsigned int, fd, umode_t, mode) return ksys_fchmod(fd, mode); } -int do_fchmodat(int dfd, const char __user *filename, umode_t mode) +int do_fchmodat4(int dfd, const char __user *filename, umode_t mode, int flags) { struct path path; int error; - unsigned int lookup_flags = LOOKUP_FOLLOW; + unsigned int lookup_flags; + + if (unlikely(flags & ~AT_SYMLINK_NOFOLLOW)) + return -EINVAL; + + lookup_flags = flags & AT_SYMLINK_NOFOLLOW ? 0 : LOOKUP_FOLLOW; + retry: error = user_path_at(dfd, filename, lookup_flags, &path); if (!error) { @@ -587,15 +593,21 @@ int do_fchmodat(int dfd, const char __user *filename, umode_t mode) return error; } +SYSCALL_DEFINE4(fchmodat4, int, dfd, const char __user *, filename, + umode_t, mode, int, flags) +{ + return do_fchmodat4(dfd, filename, mode, flags); +} + SYSCALL_DEFINE3(fchmodat, int, dfd, const char __user *, filename, umode_t, mode) { - return do_fchmodat(dfd, filename, mode); + return do_fchmodat4(dfd, filename, mode, 0); } SYSCALL_DEFINE2(chmod, const char __user *, filename, umode_t, mode) { - return do_fchmodat(AT_FDCWD, filename, mode); + return do_fchmodat4(AT_FDCWD, filename, mode, 0); } static int chown_common(const struct path *path, uid_t user, gid_t group) diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h index e1c20f1d0525..a4bde25ad264 100644 --- a/include/linux/syscalls.h +++ b/include/linux/syscalls.h @@ -433,6 +433,8 @@ asmlinkage long sys_chroot(const char __user *filename); asmlinkage long sys_fchmod(unsigned int fd, umode_t mode); asmlinkage long sys_fchmodat(int dfd, const char __user *filename, umode_t mode); +asmlinkage long sys_fchmodat4(int dfd, const char __user *filename, + umode_t mode, int flags); asmlinkage long sys_fchownat(int dfd, const char __user *filename, uid_t user, gid_t group, int flag); asmlinkage long sys_fchown(unsigned int fd, uid_t user, gid_t group); @@ -1320,11 +1322,12 @@ static inline long ksys_link(const char __user *oldname, return do_linkat(AT_FDCWD, oldname, AT_FDCWD, newname, 0); } -extern int do_fchmodat(int dfd, const char __user *filename, umode_t mode); +extern int do_fchmodat4(int dfd, const char __user *filename, umode_t mode, + int flags); static inline int ksys_chmod(const char __user *filename, umode_t mode) { - return do_fchmodat(AT_FDCWD, filename, mode); + return do_fchmodat4(AT_FDCWD, filename, mode, 0); } extern long do_faccessat(int dfd, const char __user *filename, int mode);