Debian Bug report logs - #542601
manpages-dev: mmap(2) manpage doesn't say that MAP_ANON is not available if _XOPEN_SOURCE is defined

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Message #5 received at submit@bugs.debian.org (full text, mbox, reply):

From: Török Edwin <edwintorok@gmail.com>

To: Debian Bug Tracking System <submit@bugs.debian.org>

Subject: manpages-dev: mmap(2) manpage doesn't say that MAP_ANON is not available if _XOPEN_SOURCE is defined

Date: Thu, 20 Aug 2009 14:02:50 +0300

Package: manpages-dev
Version: 3.22-1
Severity: normal

When _XOPEN_SOURCE is defined the glibc headers no longer define MAP_ANON or
MAP_ANONYMOUS (because _BSD_SOURCE is no longer defined by default).

So if I want to  use both pread(2) and mmap(2) in same C source file,
I have to define both _XOPEN_SOURCE and _BSD_SOURCE to get the prototype
for pread *and* MAP_ANON for mmap(2).

The manpage of pread(2) does say that _XOPEN_SOURCE 500 is needed, but doesn't
say that this breaks mmap. mmap's manpage doesn't say that some constants
may not be available under _XOPEN_SOURCE.

Why is _XOPEN_SOURCE 500 even needed for pread? It is a POSIX function,
and defining _XOPEN_SOURCE is not needed for other POSIX functions.
Also the POSIX manpage for pread(3p) doesn't say that _XOPEN_SOURCE is needed,
so this seems like an unnecessary complication on Linux.
If pread(2) was available w/o _XOPEN_SOURCE being defined, then the problem
with using pread and mmap would no longer exist. I think this is rather a
question for glibc though.

-- System Information:
Debian Release: squeeze/sid
  APT prefers unstable
  APT policy: (990, 'unstable'), (500, 'stable'), (1, 'experimental')
Architecture: amd64 (x86_64)

Kernel: Linux 2.6.30.4 (SMP w/4 CPU cores; PREEMPT)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/bash

Versions of packages manpages-dev depends on:
ii  manpages                      3.22-1     Manual pages about using a GNU/Lin

manpages-dev recommends no packages.

Versions of packages manpages-dev suggests:
ii  konqueror [man-browser]       4:4.3.0-1  KDE 4's advanced file manager, web
ii  man-db [man-browser]          2.5.5-3    on-line manual pager

-- no debconf information

Message #10 received at 542601@bugs.debian.org (full text, mbox, reply):

From: "Michael Kerrisk (man-pages)" <mtk.manpages@gmail.com>

To: Török Edwin <edwintorok@gmail.com>, 542601@bugs.debian.org

Cc: control@bugs.debian.org

Subject: Re: Bug#542601: manpages-dev: mmap(2) manpage doesn't say that MAP_ANON is not available if _XOPEN_SOURCE is defined

Date: Tue, 12 Feb 2013 21:42:11 +0100

tags 542601 fixed-upstream
thanks

On Thu, Aug 20, 2009 at 1:02 PM, Török Edwin <edwintorok@gmail.com> wrote:
> Package: manpages-dev
> Version: 3.22-1
> Severity: normal
>
> When _XOPEN_SOURCE is defined the glibc headers no longer define MAP_ANON or
> MAP_ANONYMOUS (because _BSD_SOURCE is no longer defined by default).
>
> So if I want to  use both pread(2) and mmap(2) in same C source file,
> I have to define both _XOPEN_SOURCE and _BSD_SOURCE to get the prototype
> for pread *and* MAP_ANON for mmap(2).
>
> The manpage of pread(2) does say that _XOPEN_SOURCE 500 is needed, but doesn't
> say that this breaks mmap. mmap's manpage doesn't say that some constants
> may not be available under _XOPEN_SOURCE.
>
> Why is _XOPEN_SOURCE 500 even needed for pread? It is a POSIX function,
> and defining _XOPEN_SOURCE is not needed for other POSIX functions.
> Also the POSIX manpage for pread(3p) doesn't say that _XOPEN_SOURCE is needed,
> so this seems like an unnecessary complication on Linux.
> If pread(2) was available w/o _XOPEN_SOURCE being defined, then the problem
> with using pread and mmap would no longer exist. I think this is rather a
> question for glibc though.

I applied the patch below upstream.

Thanks,

Michael

--- a/man2/mmap.2
+++ b/man2/mmap.2
@@ -49,6 +49,8 @@ mmap, munmap \- map or unmap files or devices into memory
 .BI "           int " fd ", off_t " offset );
 .BI "int munmap(void *" addr ", size_t " length );
 .fi
+
+See NOTES for information on feature test macro requirements.
 .SH DESCRIPTION
 .BR mmap ()
 creates a new mapping in the virtual address space of
@@ -541,6 +543,36 @@ If the
 flag is specified, and
 .I addr
 is 0 (NULL), then the mapped address will be 0 (NULL).
+
+Certain
+.I flags
+constants are defined only if either
+.BR _BSD_SOURCE
+or
+.BR _SVID_SOURCE
+is defined.
+(Requiring
+.BR _GNU_SOURCE
+also suffices,
+and requiring that macro specifically would have been more logical,
+since these flags are all Linux specific.)
+The relevant flags are:
+.BR MAP_32BIT ,
+.BR MAP_ANONYMOUS
+(and the synonym
+.BR MAP_ANON ),
+.BR MAP_DENYWRITE ,
+.BR MAP_EXECUTABLE ,
+.BR MAP_FILE ,
+.BR MAP_GROWSDOWN ,
+.BR MAP_HUGETLB ,
+.BR MAP_LOCKED ,
+.BR MAP_NONBLOCK ,
+.BR MAP_NORESERVE ,
+.BR MAP_POPULATE ,
+and
+.BR MAP_STACK .
+
 .SH BUGS
 On Linux there are no guarantees like those suggested above under
 .BR MAP_NORESERVE .


-- 
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Author of "The Linux Programming Interface"; http://man7.org/tlpi/

Message #17 received at 542601@bugs.debian.org (full text, mbox, reply):

From: Simon Paillard <spaillard@debian.org>

To: 542601@bugs.debian.org

Subject: Re: Bug#542601: manpages-dev: mmap(2) manpage doesn't say that MAP_ANON is not available if _XOPEN_SOURCE is defined

Date: Wed, 13 Feb 2013 13:32:07 +0100

On Tue, Feb 12, 2013 at 09:42:11PM +0100, Michael Kerrisk (man-pages) wrote:
> tags 542601 fixed-upstream
> thanks

FTR, it will be available in 3.48, and is:
45e97e2ac5b mmap.2: Some 'flags' values require a feature test macro to be defined
 

-- 
Simon Paillard

Message #26 received at 542601-close@bugs.debian.org (full text, mbox, reply):

From: Simon Paillard <spaillard@debian.org>

To: 542601-close@bugs.debian.org

Subject: Bug#542601: fixed in manpages 3.51-1

Date: Thu, 23 May 2013 22:48:40 +0000

Source: manpages
Source-Version: 3.51-1

We believe that the bug you reported is fixed in the latest version of
manpages, which is due to be installed in the Debian FTP archive.

A summary of the changes between this version and the previous one is
attached.

Thank you for reporting the bug, which will now be closed.  If you
have further comments please address them to 542601@bugs.debian.org,
and the maintainer will reopen the bug report if appropriate.

Debian distribution maintenance software
pp.
Simon Paillard <spaillard@debian.org> (supplier of updated manpages package)

(This message was generated automatically at their request; if you
believe that there is a problem with it please contact the archive
administrators by mailing ftpmaster@debian.org)


-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA256

Format: 1.8
Date: Thu, 23 May 2013 23:05:10 +0200
Source: manpages
Binary: manpages manpages-dev
Architecture: source all
Version: 3.51-1
Distribution: unstable
Urgency: low
Maintainer: Martin Schulze <joey@debian.org>
Changed-By: Simon Paillard <spaillard@debian.org>
Description: 
 manpages   - Manual pages about using a GNU/Linux system
 manpages-dev - Manual pages about using GNU/Linux for development
Closes: 182014 235967 533232 542601 553413 575077 578178 620746 674034 676264 692136 699387 700529 704787 705293
Changes: 
 manpages (3.51-1) unstable; urgency=low
 .
   * Imported Upstream version 3.51:
     . new manpages: kcmp.3 s390_runtime_instr.2 if_freenameindex.3
       if_indextoname.3 if_nameindex.3 if_nametoindex.3 (Closes: #235967)
       perf_event_open.2 getcontext.3 getdtablesize.3 pthread_getname_np.3
       pthread_setname_np.3 setcontext.3 sln.8
       fattach.2 fdetach.2 getmsg.2 getunwind.2 isastream.2
       perfmonctl.2 putmsg.2 nss.5
     . ttyname.3: Fix confused text in ERRORS (Closes: #676264)
     . proc.5: Add field numbers for (Closes: #553413)
     . read.2: Remove crufty text about O_NONBLOCK on files (Closes: #700529)
     . read.2: Clarify interaction of count==0 and error check (Closes: #533232)
     . getpeername.2: Clarify semantics of getpeername() for datagram
       sockets (Closes: #674034)
     . mmap.2: Some 'flags' values require a feature test macro to be
       defined (Closes: #542601)
     . resolver.3, resolv.conf.5: RES_DEBUG is only available if glibc is
       compiled with debug support (Closes: #692136)
     . stdarg.3: Describe va_copy() (Closes: #575077)
     . futimes.3: ERRORS: Add ENOSYS for lutimes() (Closes: #620746)
     . units.7: units should use an actual µ (Closes: #704787)
     . access.2: Clarify RETURN VALUE for F_OK (Closes: #705293)
     . resolv.conf.5: Document "single-request-reopen" option (Closes: #699387)
     . bootparam.7: Document 'rootfstype' option (Closes: #182014)
     . ioperm.2: Linux 2.6.8 lifted the port limit to 65,536 (Closes: #578178)
   * d/rules: build-{arch,indep} as required by policy 3.9.4
   * lintian overrides: FSSTND-dir-in-manual-page are alternate path
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