From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-10.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B9723C433E0 for ; Sun, 10 Jan 2021 10:09:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 84FC0238E9 for ; Sun, 10 Jan 2021 10:09:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726265AbhAJKJM (ORCPT ); Sun, 10 Jan 2021 05:09:12 -0500 Received: from mo4-p00-ob.smtp.rzone.de ([85.215.255.23]:30032 "EHLO mo4-p00-ob.smtp.rzone.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726267AbhAJKJL (ORCPT ); Sun, 10 Jan 2021 05:09:11 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; t=1610273118; s=strato-dkim-0002; d=clisp.org; h=References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From:From: Subject:Sender; bh=RtUf9Cq2fLmdQV5Sf2Ld7Cp97MTkDcl0QklCijzmH68=; b=nmHcgFow1VgodfIA+ciOzIewn64iyduKWc0z6orL3p6wkuPTI0WOt0HEhPS9PSJRCS 9gRYTAaGKZqggUn3RulfSRjd1gyALep9VuRPazch5+d+lHwW9o59gmJmHw+mYTraeSo2 MbPAk40Z6Ti+IxA1h+FGwpvG9idPMMxzsXS7OpTt2KbsSQFKDpfIQfWHe0q3CYHKaH6J PSt5I8wOiH95ahuuaMSO7BrXWA1T+fTtV1j8b3BiWi9zQ/KypAghqfn0wdRmApTwuWiS i7sZK0rfh9XtdlCNYuIJQ6CZ+qVPVrdYawLN5UpUhCFF6fMWPEd5pf1kxLDF+rZdvADl VPDw== X-RZG-AUTH: ":Ln4Re0+Ic/6oZXR1YgKryK8brlshOcZlIWs+iCP5vnk6shH+AHjwLuWOHqfyyvs=" X-RZG-CLASS-ID: mo00 Received: from bruno.haible.de by smtp.strato.de (RZmta 47.12.1 DYNA|AUTH) with ESMTPSA id u0aa20x0AA5HF8f (using TLSv1 with cipher ECDHE-RSA-AES256-SHA (curve X9_62_prime256v1 with 256 ECDH bits, eq. 3072 bits RSA)) (Client did not present a certificate); Sun, 10 Jan 2021 11:05:17 +0100 (CET) From: Bruno Haible To: "Dmitry V. Levin" Cc: mtk.manpages@gmail.com, linux-man@vger.kernel.org Subject: Re: [patch] chmod.2, lchmod.3: Document lchmod() Date: Sun, 10 Jan 2021 11:05:16 +0100 Message-ID: <1945428.G7aTUhjore@omega> User-Agent: KMail/5.1.3 (Linux/4.4.0-197-generic; KDE/5.18.0; x86_64; ; ) In-Reply-To: <20210110074159.GA20991@altlinux.org> References: <39277473.ZaUlkdM7pu@omega> <20210110074159.GA20991@altlinux.org> MIME-Version: 1.0 Content-Type: multipart/mixed; boundary="nextPart8260810.i6EoRtNtPx" Content-Transfer-Encoding: 7Bit Precedence: bulk List-ID: X-Mailing-List: linux-man@vger.kernel.org This is a multi-part message in MIME format. --nextPart8260810.i6EoRtNtPx Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Dmitry V. Levin wrote: > > Here is a patch to update the man pages accordingly. > > Please note the important limitation of that implementation: > it doesn't work when /proc is not mounted, see > https://sourceware.org/bugzilla/show_bug.cgi?id=26401 Thanks for the pointer. Revised patch attached. --nextPart8260810.i6EoRtNtPx Content-Disposition: attachment; filename="0001-chmod.2-lchmod.3-Document-lchmod.patch" Content-Transfer-Encoding: 7Bit Content-Type: text/x-patch; charset="UTF-8"; name="0001-chmod.2-lchmod.3-Document-lchmod.patch" >From 56ce64325fa9a9184b820eac908ecc5d53a5154b Mon Sep 17 00:00:00 2001 From: Bruno Haible Date: Sun, 10 Jan 2021 05:20:30 +0100 Subject: [PATCH] chmod.2, lchmod.3: Document lchmod(). --- man2/chmod.2 | 70 ++++++++++++++++++++++++++++++++++++++++++++++++++++++----- man3/lchmod.3 | 1 + 2 files changed, 65 insertions(+), 6 deletions(-) create mode 100644 man3/lchmod.3 diff --git a/man2/chmod.2 b/man2/chmod.2 index a54aec7..f1709ef 100644 --- a/man2/chmod.2 +++ b/man2/chmod.2 @@ -29,15 +29,16 @@ .\" : NFS details .\" Modified 2004-06-23 by Michael Kerrisk .\" -.TH CHMOD 2 2017-09-15 "Linux" "Linux Programmer's Manual" +.TH CHMOD 2 2021-01-10 "Linux" "Linux Programmer's Manual" .SH NAME -chmod, fchmod, fchmodat \- change permissions of a file +chmod, fchmod, lchmod, fchmodat \- change permissions of a file .SH SYNOPSIS .nf .B #include .PP .BI "int chmod(const char *" pathname ", mode_t " mode ); .BI "int fchmod(int " fd ", mode_t " mode ); +.BI "int lchmod(const char *" pathname ", mode_t " mode ); .PP .BR "#include " " /* Definition of AT_* constants */" .B #include @@ -68,6 +69,12 @@ Feature Test Macro Requirements for glibc (see .\" || (_XOPEN_SOURCE && _XOPEN_SOURCE_EXTENDED) .fi .PP +.BR lchmod (): +.nf + Since glibc 2.32: + _DEFAULT_SOURCE +.fi +.PP .BR fchmodat (): .nf Since glibc 2.10: @@ -80,10 +87,12 @@ The .BR chmod () and .BR fchmod () -system calls change a files mode bits. +system calls and the +.BR lchmod () +function change a file's mode bits. (The file mode consists of the file permission bits plus the set-user-ID, set-group-ID, and sticky bits.) -These system calls differ only in how the file is specified: +These functions differ only in how the file is specified: .IP * 2 .BR chmod () changes the mode of the file specified whose pathname is given in @@ -93,6 +102,11 @@ which is dereferenced if it is a symbolic link. .BR fchmod () changes the mode of the file referred to by the open file descriptor .IR fd . +.IP * +.BR lchmod () +is like +.BR chmod (), +but does not dereference symbolic links. .PP The new file mode is specified in .IR mode , @@ -220,8 +234,13 @@ can either be 0, or include the following flag: If .I pathname is a symbolic link, do not dereference it: -instead operate on the link itself. -This flag is not currently implemented. +instead operate on the link itself, like +.BR lchmod (). +(By default, +.BR fchmodat () +dereferences symbolic links, like +.BR chmod ().) +This flag is implemented since glibc 2.32. .PP See .BR openat (2) @@ -304,6 +323,17 @@ See above. The same errors that occur for .BR chmod () can also occur for +.BR lchmod (). +The following additional errors can occur for +.BR lchmod (): +.TP +.B EOPNOTSUPP +.B /proc +is not mounted. +.PP +The same errors that occur for +.BR chmod () +can also occur for .BR fchmodat (). The following additional errors can occur for .BR fchmodat (): @@ -323,14 +353,31 @@ is relative and is a file descriptor referring to a file other than a directory. .TP .B ENOTSUP +(Before glibc 2.32.) .I flags specified .BR AT_SYMLINK_NOFOLLOW , which is not supported. +.TP +.B EOPNOTSUPP +(Since glibc 2.32.) +.I flags +specified +.BR AT_SYMLINK_NOFOLLOW , +and +.B /proc +is not mounted. .SH VERSIONS .BR fchmodat () was added to Linux in kernel 2.6.16; library support was added to glibc in version 2.4. +.PP +.BR lchmod () +and the handling of +.B AT_SYMLINK_NOFOLLOW +in +.BR fchmodat () +were added in glibc version 2.32. .SH CONFORMING TO .BR chmod (), .BR fchmod (): @@ -362,6 +409,17 @@ glibc constructs a pathname based on the symbolic link in that corresponds to the .IR dirfd argument. +.SH BUGS +.BR lchmod () +and +.BR fchmodat () +with +.B AT_SYMLINK_NOFOLLOW +flag fail with error +.B EOPNOTSUPP +when the +.B /proc +file system is not mounted. .SH SEE ALSO .BR chmod (1), .BR chown (2), diff --git a/man3/lchmod.3 b/man3/lchmod.3 new file mode 100644 index 0000000..92647d2 --- /dev/null +++ b/man3/lchmod.3 @@ -0,0 +1 @@ +.so man2/chmod.2 -- 2.7.4 --nextPart8260810.i6EoRtNtPx--