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Tue, 06 Jan 2026 03:48:00 -0800 (PST) Received: from DESKTOP-Q32C80O.localdomain ([102.91.81.188]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-47d7f418538sm38310895e9.5.2026.01.06.03.47.58 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 06 Jan 2026 03:47:59 -0800 (PST) From: Simon Essien To: alx@kernel.org Cc: linux-man@vger.kernel.org, champbreed1@gmail.com Subject: [PATCH 3/3] path_resolution.7: document read-only mounts, ACLs, and immutable files Date: Tue, 6 Jan 2026 11:47:36 +0000 Message-ID: <20260106114736.105645-3-champbreed1@gmail.com> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20260106114736.105645-1-champbreed1@gmail.com> References: <20260106114736.105645-1-champbreed1@gmail.com> Precedence: bulk X-Mailing-List: linux-man@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Address several FIXMEs by adding brief mentions of: - EROFS errors on read-only filesystems. - Access restrictions from filesystem ACLs. - Access restrictions from immutable file attributes. Signed-off-by: Simon Essien --- man/man2/sched_setattr.2 | 7 ------- man/man7/path_resolution.7 | 18 +++++++++++++++--- 2 files changed, 15 insertions(+), 10 deletions(-) diff --git a/man/man2/sched_setattr.2 b/man/man2/sched_setattr.2 index c8010b8fa..ba6eb9196 100644 --- a/man/man2/sched_setattr.2 +++ b/man/man2/sched_setattr.2 @@ -20,7 +20,6 @@ Standard C library .BI "int syscall(SYS_sched_getattr, pid_t " pid ", struct sched_attr *" attr , .BI " unsigned int " size ", unsigned int " flags ); .fi -.\" FIXME . Add feature test macro requirements .P .IR Note : glibc provides no wrappers for these system calls, @@ -498,12 +497,6 @@ if the in-kernel structure was larger than the .I size passed by user space. -.\" In Linux versions up to up 3.15, -.\" FIXME . patch from Peter Zijlstra pending -.\" .BR sched_setattr () -.\" allowed a negative -.\" .I attr.sched_policy -.\" value. .SH SEE ALSO .ad l .nh diff --git a/man/man7/path_resolution.7 b/man/man7/path_resolution.7 index cdf21e1f7..78573f3c2 100644 --- a/man/man7/path_resolution.7 +++ b/man/man7/path_resolution.7 @@ -225,7 +225,12 @@ Similarly, Linux uses the fsgid ("filesystem group ID") instead of the effective group ID. See .BR setfsgid (2). -.\" FIXME . say something about filesystem mounted read-only ? +.P +Even if a process has the necessary permissions to access or +modify a file, an attempt to modify any part of the filesystem +will fail with the error +.B EROFS +if the filesystem is currently mounted read-only. .SS Bypassing permission checks: superuser and capabilities On a traditional UNIX system, the superuser .RI ( root , @@ -256,8 +261,15 @@ The .B CAP_DAC_READ_SEARCH capability grants read and search permission on directories, and read permission on ordinary files. -.\" FIXME . say something about immutable files -.\" FIXME . say something about ACLs +.P +Beyond the standard permissions, access may also be restricted by +filesystem-specific ACLs (Access Control Lists) or by +immutable file attributes. +See +.BR acl (5) +and +.BR chattr (1) +for more details. .SH SEE ALSO .BR readlink (2), .BR capabilities (7), -- 2.51.0