path: root/Changes

==================== Changes in man-pages-3.82 ====================

Released: ????-??-??, Paris

Eric W. Biederman <ebiederm@xmission.com>
Heinrich Schuchardt <xypron.glpk@gmx.de>
Jakub Wilk <ubanus@users.sf.net>
Jann Horn <jann@thejh.net>
Jason Vas Dias <jason.vas.dias@gmail.com>
Josh Triplett <josh@joshtriplett.org>
J William Piggott <elseifthen@gmx.com>
Kees Cook <keescook@chromium.org>
Konstantin Shemyak <konstantin@shemyak.com>
Ma Shimiao <mashimiao.fnst@cn.fujitsu.com>
Matt Turner <mattst88@gmail.com>
Michael Kerrisk <mtk.manpages@gmail.com>
Michael Witten <mfwitten@gmail.com>
Mikael Pettersson <mikpelinux@gmail.com>
Namhyung Kim <namhyung@gmail.com>
Nicolas FRANCOIS <nicolas.francois@centraliens.net>
Paul E Condon <pecondon@mesanetworks.net>
Peter Adkins <peter.adkins@kernelpicnic.net>
Scot Doyle <lkml14@scotdoyle.com>
Shawn Landden <shawn@churchofgit.com>
Stéphane Aulery <saulery@free.fr>
Stephen Smalley <sds@tycho.nsa.gov>
Taisuke Yamada <tai@rakugaki.org>
Torvald Riegel <triegel@redhat.com>
Vincent Lefevre <vincent@vinc17.net>
<ygrex@ygrex.ru>
Yuri Kozlov <yuray@komyakino.ru>


Contributors
------------

The following people contributed patches/fixes or (noted in brackets
in the changelog below) reports, notes, and ideas that have been
incorporated in changes in this release:

Alban Crequy <alban.crequy@gmail.com>
Andy Lutomirski <luto@amacapital.net>
Bert Wesarg <bert.wesarg@googlemail.com>
Bill Pemberton <wfp5p@worldbroken.com>
Chris Delozier <c.s.delozier@gmail.com>
David Madore <david.madore@ens.fr>
Dmitry Deshevoy <mityada@gmail.com>
Eric W. Biederman <ebiederm@xmission.com>
Heinrich Schuchardt <xypron.glpk@gmx.de>
Jakub Wilk <ubanus@users.sf.net>
Jann Horn <jann@thejh.net>
Jason Vas Dias <jason.vas.dias@gmail.com>
Josh Triplett <josh@joshtriplett.org>
J William Piggott <elseifthen@gmx.com>
Kees Cook <keescook@chromium.org>
Konstantin Shemyak <konstantin@shemyak.com>
Ma Shimiao <mashimiao.fnst@cn.fujitsu.com>
Matt Turner <mattst88@gmail.com>
Michael Kerrisk <mtk.manpages@gmail.com>
Michael Witten <mfwitten@gmail.com>
Mikael Pettersson <mikpelinux@gmail.com>
Namhyung Kim <namhyung@gmail.com>
Nicolas FRANCOIS <nicolas.francois@centraliens.net>
Paul E Condon <pecondon@mesanetworks.net>
Peter Adkins <peter.adkins@kernelpicnic.net>
Scot Doyle <lkml14@scotdoyle.com>
Shawn Landden <shawn@churchofgit.com>
Stéphane Aulery <saulery@free.fr>
Stephen Smalley <sds@tycho.nsa.gov>
Taisuke Yamada <tai@rakugaki.org>
Torvald Riegel <triegel@redhat.com>
Vincent Lefevre <vincent@vinc17.net>
<ygrex@ygrex.ru>
Yuri Kozlov <yuray@komyakino.ru>

Apologies if I missed anyone!


New and rewritten pages
-----------------------

nptl.7
    Michael Kerrisk
        New page with details of the NPTL POSIX threads implementation


Newly documented interfaces in existing pages
---------------------------------------------

user_namespaces.7
    Eric W. Biederman  [Michael Kerrisk]
        Document /proc/[pid]/setgroups


Changes to individual pages
---------------------------

intro.1
    Stéphane Aulery
        Prompt is not % but $
    Stéphane Aulery
        Various improvements
            - Add reference to other common shells dash(1), ksh(1)
            - Add a reference to stdout(3)
            - Separate cp and mv descriptions
            - Add examples of special cases of cd
            - Add su(1) and shutdown(8) references for section Logout
              and poweroff
            - Move Control-D to section Logout and poweroff
            - Fix some little formatting errors
    Stéphane Aulery
        Add cross references cited
    Stéphane Aulery
        Order SEE ALSO section

clone.2
    Josh Triplett
        Document that clone() silently ignores CLONE_PID and CLONE_STOPPED
            Normally, system calls return EINVAL for flags they don't support.
            Explicitly document that clone does *not* produce an error for
            these two obsolete flags.
    Michael Kerrisk
        Small rewording of explanation of clone() wrt threads
            Clone has so many effects that it's an oversimplification to say
            that the *main* use of clone is to create a thread.  (In fact,
            the use of clone() to create new processes may well be more
            common, since glibc's fork() is a wrapper that calls clone().)

getgroups.2
    Michael Kerrisk  [Shawn Landden]
        Add discussion of NPTL credential-changing mechanism
            At the kernel level, credentials (UIDs and GIDs) are a per-thread
            attribute. NPTL uses a signal-based mechanism to ensure that
            when one thread changes its credentials, all other threads change
            credentials to the same values. By this means, the NPTL
            implementation conforms to the POSIX requirement that the threads
            in a process share credentials.
    Michael Kerrisk
        ERRORS: add EPERM for the case where /proc/PID/setgroups is "deny"
    Michael Kerrisk
        Note capability associated with EPERM error for setgroups(2)
    Michael Kerrisk
        Refer reader to user_namespaces(7) for discussion of /proc/PID/setgroups
            The discussion of /proc/PID/setgroups has moved from
            proc(5) to user_namespaces(7).

getpid.2
    Michael Kerrisk
        Note that getppid() returns 0 if parent is in different PID namespace

getsockopt.2
    Konstantin Shemyak
        Note RETURN VALUE details when netfilter is involved

ioctl_list.2
    Heinrich Schuchardt
        SEE ALSO ioctl_fat.2
            Add FAT_IOCTL_GET_VOLUME_ID
            SEE ALSO ioctl_fat.2
    Heinrich Schuchardt
        include/linux/ext2_fs.h
            Include linux/ext2_fs.h does not contain any ioctl definitions
            anymore.

            Request codes EXT2_IOC* have been replaced by FS_IOC* in
            linux/fs.h.

            Some definitions of FS_IOC_* use long* but the actual code expects
            int* (see fs/ext2/ioctl.c).

msgop.2
    Bill Pemberton
        Remove EAGAIN as msgrcv() errno
            The list of errnos for msgrcv() lists both EAGAIN and ENOMSG as
            the errno for no message available with the IPC_NOWAIT flag.
            ENOMSG is the errno that will be set.
    Bill Pemberton
        Add an example program

open.2
    Michael Kerrisk  [Jason Vas Dias]
        Mention blocking semantics for FIFO opens
            See https://bugzilla.kernel.org/show_bug.cgi?id=95191

seccomp.2
    Jann Horn  [Kees Cook, Mikael Pettersson, Andy Lutomirski]
        Add note about alarm(2) not being sufficient to limit runtime
    Jann Horn
        Explain blacklisting problems, expand example
    Michael Kerrisk  [Kees Cook]
        Add mention of libseccomp

setgid.2
    Michael Kerrisk
        Clarify that setgid() changes all GIDs when caller has CAP_SETGID
    Michael Kerrisk  [Shawn Landden]
        Add discussion of NPTL credential-changing mechanism
            At the kernel level, credentials (UIDs and GIDs) are a per-thread
            attribute. NPTL uses a signal-based mechanism to ensure that
            when one thread changes its credentials, all other threads change
            credentials to the same values. By this means, the NPTL
            implementation conforms to the POSIX requirement that the threads
            in a process share credentials.

setresuid.2
    Michael Kerrisk  [Shawn Landden]
        Add discussion of NPTL credential-changing mechanism
            At the kernel level, credentials (UIDs and GIDs) are a per-thread
            attribute. NPTL uses a signal-based mechanism to ensure that
            when one thread changes its credentials, all other threads change
            credentials to the same values. By this means, the NPTL
            implementation conforms to the POSIX requirement that the threads
            in a process share credentials.

setreuid.2
    Michael Kerrisk  [Shawn Landden]
        Add discussion of NPTL credential-changing mechanism
            At the kernel level, credentials (UIDs and GIDs) are a per-thread
            attribute. NPTL uses a signal-based mechanism to ensure that
            when one thread changes its credentials, all other threads change
            credentials to the same values. By this means, the NPTL
            implementation conforms to the POSIX requirement that the threads
            in a process share credentials.
    Michael Kerrisk
        SEE ALSO: add credentials(7)

setuid.2
    Michael Kerrisk
        Clarify that setuid() changes all UIDs when caller has CAP_SETUID
    Michael Kerrisk  [Shawn Landden]
        Add discussion of NPTL credential-changing mechanism
            At the kernel level, credentials (UIDs and GIDs) are a per-thread
            attribute. NPTL uses a signal-based mechanism to ensure that
            when one thread changes its credentials, all other threads change
            credentials to the same values. By this means, the NPTL
            implementation conforms to the POSIX requirement that the threads
            in a process share credentials.

sigaction.2
    Michael Kerrisk
        Add discussion of rt_sigaction(2)
    Michael Kerrisk
        Note treatment of signals used internally by NPTL
            The glibc wrapper gives an EINVAL error on attempts to change the
            disposition of either of the two real-time signals used by NPTL.

sigpending.2
    Michael Kerrisk
        Add discussion of rt_sigpending(2)

sigprocmask.2
    Michael Kerrisk
        Add discussion of rt_sigprocmask(2)
    Michael Kerrisk
        Note treatment of signals used internally by NPTL
            The glibc wrapper silently ignores attempts to block the two
            real-time signals used by NPTL.

sigreturn.2
    Michael Kerrisk
        Add discussion of rt_sigreturn(2)

sigsuspend.2
    Michael Kerrisk
        Add discussion of rt_sigsuspend(2)

sigwaitinfo.2
    Michael Kerrisk
        Note treatment of signals used internally by NPTL
            The glibc wrappers silently ignore attempts to wait for
            signals used by NPTL.
    Michael Kerrisk
        Add discussion of rt_sigtimedwait(2)

socket.2
    Heinrich Schuchardt
        SEE ALSO close(2)
            The description mentions close(2). Hence it should also be
            referenced in the SEE ALSO section.

syscall.2
    Jann Horn
        Add x32 ABI

umount.2
    Eric W. Biederman
        Document the effect of shared subtrees on umount(2)
    Eric W. Biederman
        Correct the description of MNT_DETACH
            I recently realized that I had been reasoning improperly about
            what umount(MNT_DETACH) did based on an insufficient description
            in the umount.2 man page, that matched my intuition but not the
            implementation.

            When there are no submounts, MNT_DETACH is essentially harmless to
            applications.  Where there are submounts, MNT_DETACH changes what
            is visible to applications using the detach directories.
    Michael Kerrisk
        Move "shared mount + umount" text to a subsection in NOTES

aio_return.3
    Stéphane Aulery
        Document the return value on error
            Reported by Alexander Holler <holler@ahsoftware.de>

clock.3
    Stéphane Aulery
        CLOCKS_PER_SEC = 1000000 is required by XSI, not POSIX
            Debian Bug #728213 reported by Tanaka Akira <akr@fsij.org>

            See https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=728213

dlopen.3
    Michael Kerrisk
        Amend error in description of dlclose() behavior
            The current text says that unloading depends on whether
            the reference count falls to zero *and no other libraries
            are using symbols in this library*. That latter text has
            been there since man-pages-1.29, but it seems rather dubious.
            How could the implementation know whether other libraries
            are still using symbols in this library? Furthermore, no
            other implementation's man page mentions this point.
            Seems best to drop this point.
    Michael Kerrisk
        Add some details for RTLD_DEFAULT
    Michael Kerrisk
        Add some details on RTLD_NEXT and preloading
    Michael Kerrisk
        RTLD_NEXT works for symbols generally, not just functions
            The common use case is for functions, but RTLD_NEXT
            also applies to variable symbols.
    Michael Kerrisk
        dlclose() recursively closes dependent libraries
            Note that dlclose() recursively closes dependent libraries
            that were loaded by dlopen()
    Michael Kerrisk
        Rename second dlopen() argument from "flag" to "flags"
            This is more consistent with other such arguments
    Michael Kerrisk
        Reformat text on RTLD_DEFAULT and RTLD_NEXT

fmemopen.3
    Ma Shimiao
        ATTRIBUTES: Note functions that are thread-safe
            The markings match glibc markings.

fpathconf.3
    Ma Shimiao
        ATTRIBUTES: Note functions that are thread-safe
            The marking matches glibc marking.

fputwc.3
    Ma Shimiao
        ATTRIBUTES: Note functions that are thread-safe
            The marking matches glibc marking.

fputws.3
    Ma Shimiao
        ATTRIBUTES: Note function that is thread-safe
            The marking matches glibc marking.

fseek.3
    Ma Shimiao
        ATTRIBUTES: Note functions that are thread-safe
            The markings match glibc markings.

fseeko.3
    Ma Shimiao
        ATTRIBUTES: Note functions that are thread-safe
            The markings match glibc markings.

gcvt.3
    Ma Shimiao
        ATTRIBUTES: Note function that is thread-safe
            The marking matches glibc marking.

getline.3
    Ma Shimiao
        ATTRIBUTES: Note functions that are thread-safe
            The marking matches glibc marking.

getwchar.3
    Ma Shimiao
        ATTRIBUTES: Note function that is thread-safe
            The marking matches glibc marking.

hypot.3
    Ma Shimiao
        ATTRIBUTES: Note functions that are thread-safe
            The markings match glibc markings.

iconv_open.3
    Ma Shimiao
        ATTRIBUTES: Note function that is thread-safe
            The marking matches glibc marking.

if_nameindex.3
    Ma Shimiao
        ATTRIBUTES: Note functions that are thread-safe
            The markings match glibc markings.

initgroups.3
    Ma Shimiao
        ATTRIBUTES: Note function that is thread-safe
            The markings match glibc markings.

mq_open.3
    Torvald Riegel
        Add EINVAL error case for invalid name
            This behavior is implementation-defined by POSIX.  If the name
            doesn't start with a '/', glibc returns EINVAL without attempting
            the syscall.

popen.3
    Ma Shimiao
        ATTRIBUTES: Note functions that are thread-safe
            The marking matches glibc marking.

pthread_kill.3
    Michael Kerrisk
        Note treatment of signals used internally by NPTL
            The glibc pthread_kill() function gives an error on attempts
            to send either of the real-time signals used by NPTL.

pthread_sigmask.3
    Michael Kerrisk
        Note treatment of signals used internally by NPTL
            The glibc implementation silently ignores attempts to block the two
            real-time signals used by NPTL.

pthread_sigqueue.3
    Michael Kerrisk
        Note treatment of signals used internally by NPTL
            The glibc pthread_sigqueue() function gives an error on attempts
            to send either of the real-time signals used by NPTL.

resolver.3
    Stéphane Aulery  [Jakub Wilk]
        Document missing options used by _res structure indicate defaults
            Missing options: RES_INSECURE1, RES_INSECURE2, RES_NOALIASES,
            USE_INET6, ROTATE, NOCHECKNAME, RES_KEEPTSIG, BLAST, USEBSTRING,
            NOIP6DOTINT, USE_EDNS0, SNGLKUP, SNGLKUPREOP, RES_USE_DNSSEC,
            NOTLDQUERY, DEFAULT

            Written from the glibc source and resolv.conf.5.

            See https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=527136
    Stéphane Aulery
        RES_IGNTC is implemented

rint.3
    Matt Turner
        Document that halfway cases are rounded to even
            Per IEEE-754 rounding rules.

            The round(3) page describes the behavior of rint and nearbyint
            in the halfway cases by saying:

                These functions round x to the nearest integer, but round
                halfway cases away from zero [...], instead of to the
                nearest even integer like rint(3)

sigqueue.3
    Michael Kerrisk
        NOTES: add "C library/kernel ABI differences" subheading
    Michael Kerrisk
        Clarify version info (mention rt_sigqueueinfo())

sigsetops.3
    Michael Kerrisk
        Note treatment of signals used internally by NPTL
            The glibc sigfillset() function excludes the two real-time
            signals used by NPTL.

sigwait.3
    Michael Kerrisk
        Note treatment of signals used internally by NPTL
            The glibc sigwait() silently ignore attempts to wait for
            signals used by NPTL.

strcoll.3
    Ma Shimiao
        ATTRIBUTES: Note function that is thread-safe
            The markings match glibc markings.

strdup.3
    Ma Shimiao
        ATTRIBUTES: Note functions that are thread-safe
            The marking matches glibc marking.

tzset.3
    J William Piggott
        Add 'std' quoting information

ulimit.3
    Ma Shimiao
        ATTRIBUTES: Note function that is thread-safe
            The marking matches glibc marking.

wcstombs.3
    Ma Shimiao
        ATTRIBUTES: Note function that is thread-safe
            The marking matches glibc marking.

wctob.3
    Ma Shimiao
        ATTRIBUTES: Note function that is thread-safe
            The marking matches glibc marking.

xdr.3
    Taisuke Yamada
        Clarified incompatibility and correct usage of XDR API
            See http://bugs.debian.org/628099

console_codes.4
    Scot Doyle
        Add Console Private CSI sequence 15
            An undocumented escape sequence in drivers/tty/vt/vt.c brings the
            previously accessed virtual terminal to the foreground.
            mtk: Patch misattributed to Taisuke Yamada in Git commit
            because of a muck up on my part.
    Michael Kerrisk
        Add kernel version number for CSI sequence 15

random.4
    Michael Kerrisk
        Fix permissions shown for the devices
            These days, the devices are RW for everyone.

filesystems.5
    Michael Kerrisk
        Remove dubious claim about comparative performance of ext2
            Perhaps it was the best filesystem performance-wise in
            the 20th century, when that text was written. That probably
            ceased to be true quite a long time ago, though.
    Stéphane Aulery
        Add cross references for ext filesystems
    Stéphane Aulery
        Specifies the scope of this list and its limits.

host.conf.5
hosts.5
resolv.conf.5
    Stéphane Aulery  [Paul E Condon]
        Cross references of these pages.
            See https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=298259

host.conf.5
    Stéphane Aulery
        Rework discussion of nospoof, spoofalert, spoof and RESOLV_SPOOF_CHECK
            The keywords and environment variables "nospoof", "spoofalert",
            "spoof" and RESOLV_SPOOF_CHECK were added to glibc 2.0.7 but
            never implemented

            Move descriptions to historical section and reorder it for clarity

            See https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=773443

hosts.5
    Stéphane Aulery  [Vincent Lefevre]
        Mention 127.0.1.1 for FQDN and IPv6 examples
            See https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=562890

proc.5
    Taisuke Yamada
        Document /proc/PID/status VmPin field
            See https://bugs.launchpad.net/bugs/1071746
    Michael Kerrisk
        Document (the obsolete) /proc/PID/seccomp
    Michael Kerrisk
        Replace description of 'uid_map' with a reference to user_namespaces(7)
            All of the information in proc(5) was also present in
            user_namespaces(7), but the latter was more detailed
            and up to date.
    Taisuke Yamada
        Fix SELinux /proc/pid/attr/current example
            Since the /proc/pid/attr API was added to the kernel, there
            have been a couple of changes to the SELinux handling of
            /proc/pid/attr/current.  Fix the SELinux /proc/pid/attr/current
            example text to reflect these changes and note which kernel
            versions first included the changes.

securetty.5
    Stéphane Aulery  [Nicolas FRANCOIS]
        Note that the pam_securetty module also uses this file
            See https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=528015

            This patch is a modified version of the one proposed without
            parts specific to Debian.

boot.7
    Michael Witten
        Copy edit
            While a lot of the changes are issues of presentation,
            there are also issues of grammar and punctuation.
    Michael Witten
        Mention `systemd(1)' and its related `bootup(7)'
            It's important that the reader receive contemporary information.

credentials.7
    Michael Kerrisk
        SEE ALSO: add pthreads(7)
    Michael Kerrisk
        Add reference to nptl(7)

feature_test_macros.7
    Michael Kerrisk
        Update discussion of _FORTIFY_SOURCE
            Since the initial implementation a lot more checks were added.
            Describe all the checks would be too verbose (and would soon
            fall out of date as more checks are added). So instead, describe
            the kinds of checks that are done more generally.
            Also a few other minor edits to the text.

hier.7
    Stéphane Aulery
        First patch of a series to achieve compliance with FHS 2.3
    Stéphane Aulery
        SGML and XML directories are separated in FHS 2.3
    Stéphane Aulery
        Add missing directories defined by FHS 2.3
    Stéphane Aulery
        Identify which directories are optional
    Stéphane Aulery
        Document /initrd, /lost+found and /sys
            Ubuntu Bug #70094 reported by Brian Beck
            https://bugs.launchpad.net/ubuntu/+source/manpages/+bug/70094
    Stéphane Aulery
        Explain YP, which is not obvious

ipv6.7
    Stéphane Aulery  [David Madore]
        SOL_IPV6 and other SOL_* options socket are not portable
            See https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=472447

man-pages.7
    Michael Kerrisk  [Bill Pemberton]
        Add indent(1) command that produces desired formatting for example code
    Stéphane Aulery
        Improve description of sections in accordance with intro pages

packet.7
    Michael Kerrisk
        Rework description of fanout algorithms as list
    Michael Kerrisk
        Remove mention of needing UID 0 to create packet socket
            The existing text makes no sense. The check is based
            purely on a capability check. (Kernel function
            net/packet/af_packet.c::packet_create()
    Michael Kerrisk
        Remove text about ancient glibc not defining SOL_PACKET
            This was fixed in glibc 2.1.1, which is a long while ago.
            And in any case, there is nothing special about this case;
            it's just one of those times when glibc lags.
    Michael Kerrisk
        Rework description of 'sockaddr_ll' fields as a list
    Michael Kerrisk
        Various minor edits

pthreads.7
    Michael Kerrisk
        Add references to nptl(7)

raw.7
    Michael Kerrisk
        Rephrase "Linux 2.2" language to "Linux 2.2 or later"
            The man page was written in the LInux 2.2 timeframe, and
            some phrasing was not future-proof.

signal.7
    Michael Kerrisk
        Note when Linux added realtime signals
    Michael Kerrisk
        Correct the range of realtime signals
    Michael Kerrisk
        Summarize 2.2 system call changes that resulted from larger signal sets
    Michael Kerrisk
        SEE ALSO: add nptl(7)

tcp.7
    Peter Adkins
        Document removal of TCP_SYNQ_HSIZE
            Looking over the man page for 'tcp' I came across a reference to
            tuning the 'TCP_SYNQ_HSIZE' parameter when increasing
            'tcp_max_syn_backlog' above 1024. However, this static sizing was
            removed back in Linux 2.6.20 in favor of dynamic scaling - as
            part of commit 72a3effaf633bcae9034b7e176bdbd78d64a71db.

user_namespaces.7
    Eric W. Biederman
        Update the documentation to reflect the fixes for negative groups
            Files with access permissions such as rwx---rwx give fewer
            permissions to their group then they do to everyone else.  Which
            means dropping groups with setgroups(0, NULL) actually grants a
            process privileges.

            The unprivileged setting of gid_map turned out not to be safe
            after this change.  Privileged setting of gid_map can be
            interpreted as meaning yes it is ok to drop groups. [ Eric
            additionally noted: Setting of gid_map with privilege has been
            clarified to mean that dropping groups is ok.  This allows
            existing programs that set gid_map with privilege to work
            without changes.  That is, newgidmap(1) continues to work
            unchanged.]

            To prevent this problem and future problems, user namespaces were
            changed in such a way as to guarantee a user can not obtain
            credentials without privilege that they could not obtain without
            the help of user namespaces.

            This meant testing the effective user ID and not the filesystem
            user ID, as setresuid(2) and setregid(2) allow setting any process
            UID or GID (except the supplementary groups) to the effective ID.

            Furthermore, to preserve in some form the useful applications
            that have been setting gid_map without privilege, the file
            /proc/[pid]/setgroups was added to allow disabling setgroups(2).
            With setgroups(2) permanently disabled in a user namespace, it
            again becomes safe to allow writes to gid_map without privilege.
    Michael Kerrisk
        Rework some text describing permission rules for updating map files
            No (intentional) change to the facts, but this restructuring
            should make the meaning easier to grasp.
    Michael Kerrisk
        Update kernel version associated with 5-line limit for map files
            As at Linux 3.18, the limit is still five lines, so mention the
            more recent kernel version in the text.
    Michael Kerrisk  [Alban Crequy]
        Handle /proc/PID/setgroups in the example program
    Michael Kerrisk
        Rework text describing restrictions on updating /proc/PID/setgroups
            No (intentional) changes to factual description, but the
            restructured text is hopefully easier to grasp.
    Michael Kerrisk
        Explain why the /proc/PID/setgroups file was added

ldconfig.8
    Michael Kerrisk
        Note use of /lib64 and /usr/lib64 on some 64-bit architectures

ld.so.8
    Michael Kerrisk
        Note the use of /lib64 and /usr/lib64 on some 64-bit architectures