[patch] chmod.2, lchmod.3: Document lchmod()

[Bruno Haible <bruno@clisp.org>]

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Hi,

lchmod (= the effect of fchmod with flag AT_SYMLINK_NOFOLLOW)
is implemented since glibc 2.32, see
https://sourceware.org/bugzilla/show_bug.cgi?id=14578
https://sourceware.org/git/?p=glibc.git;a=commitdiff;h=752dd17443e55a4535cb9e6baa4e550ede383540

Here is a patch to update the man pages accordingly.



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From 22cbd89a89bc26a518537739d677a5736727738f Mon Sep 17 00:00:00 2001
From: Bruno Haible <bruno@clisp.org>
Date: Sun, 10 Jan 2021 05:20:30 +0100
Subject: [PATCH] chmod.2, lchmod.3: Document lchmod().

---
 man2/chmod.2  | 25 +++++++++++++++++++++----
 man3/lchmod.3 |  1 +
 2 files changed, 22 insertions(+), 4 deletions(-)
 create mode 100644 man3/lchmod.3

diff --git a/man2/chmod.2 b/man2/chmod.2
index a54aec7..897dd87 100644
--- a/man2/chmod.2
+++ b/man2/chmod.2
@@ -29,15 +29,16 @@
 .\"   <michael@cantor.informatik.rwth-aachen.de>: NFS details
 .\" Modified 2004-06-23 by Michael Kerrisk <mtk.manpages@gmail.com>
 .\"
-.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 <sys/stat.h>
 .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 <fcntl.h>" "           /* Definition of AT_* constants */"
 .B #include <sys/stat.h>
@@ -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:
@@ -93,6 +100,11 @@ 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 +232,13 @@ 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)
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