source: trunk/server/docs-xml/Samba3-HOWTO/TOSHARG-Portability.xml

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<!DOCTYPE chapter PUBLIC "-//Samba-Team//DTD DocBook V4.2-Based Variant V1.0//EN" "http://www.samba.org/samba/DTD/samba-doc">
<chapter id="Portability">
<chapterinfo>
        &author.jelmer;
        &author.jht;
        <!-- Some other people as well, but there were no author names in the text files this file is based on-->
</chapterinfo>

<title>Portability</title>

<para>
<indexterm><primary>platforms</primary></indexterm>
<indexterm><primary>compatible</primary></indexterm>
Samba works on a wide range of platforms, but the interface all the 
platforms provide is not always compatible. This chapter contains 
platform-specific information about compiling and using Samba.</para>

<sect1>
<title>HPUX</title>

<para>
<indexterm><primary>/etc/logingroup</primary></indexterm>
<indexterm><primary>/etc/group</primary></indexterm>
Hewlett-Packard's implementation of supplementary groups is nonstandard (for
historical reasons). There are two group files, <filename>/etc/group</filename> and
<filename>/etc/logingroup</filename>; the system maps UIDs to numbers using the former, but
initgroups() reads the latter. Most system admins who know the ropes
symlink <filename>/etc/group</filename> to <filename>/etc/logingroup</filename>
(hard-link does not work for reasons too obtuse to go into here). initgroups() will complain if one of the
groups you're in, in <filename>/etc/logingroup</filename>, has what it considers to be an invalid
ID, which means outside the range <constant>[0..UID_MAX]</constant>, where <constant>UID_MAX</constant> is
60000 currently on HP-UX. This precludes -2 and 65534, the usual <constant>nobody</constant>
GIDs.
</para>

<para>
If you encounter this problem, make sure the programs that are failing 
to initgroups() are run as users, not in any groups with GIDs outside the 
allowed range.
</para>

<para>
This is documented in the HP manual pages under setgroups(2) and passwd(4).
</para>

<para>
<indexterm><primary>gcc</primary></indexterm>
<indexterm><primary>ANSI compiler</primary></indexterm>
On HP-UX you must use gcc or the HP ANSI compiler. The free compiler
that comes with HP-UX is not ANSI compliant and cannot compile Samba.
</para>

</sect1>

<sect1>
<title>SCO UNIX</title>

<para> 
If you run an old version of SCO UNIX, you may need to get important 
TCP/IP patches for Samba to work correctly. Without the patch, you may 
encounter corrupt data transfers using Samba.
</para>

<para>
The patch you need is UOD385 Connection Drivers SLS. It is available from
SCO <ulink noescape="1" url="ftp://ftp.sco.com/">ftp.sco.com</ulink>, directory SLS,
files uod385a.Z and uod385a.ltr.Z).
</para>

<para>
The information provided here refers to an old version of SCO UNIX. If you require
binaries for more recent SCO UNIX products, please contact SCO to obtain packages that are
ready to install. You should also verify with SCO that your platform is up to date for the
binary packages you will install. This is important if you wish to avoid data corruption
problems with your installation. To build Samba for SCO UNIX products  may
require significant patching of Samba source code. It is much easier to obtain binary
packages directly from SCO.
</para>

</sect1>

<sect1>
<title>DNIX</title>

<para>
DNIX has a problem with seteuid() and setegid(). These routines are
needed for Samba to work correctly, but they were left out of the DNIX
C library for some reason.
</para>

<para>
For this reason Samba by default defines the macro NO_EID in the DNIX
section of includes.h. This works around the problem in a limited way,
but it is far from ideal, and some things still will not work right.
</para>

<para> 
To fix the problem properly, you need to assemble the following two
functions and then either add them to your C library or link them into
Samba. Put the following in the file <filename>setegid.s</filename>:
</para>

<para><programlisting>
        .globl  _setegid
_setegid:
        moveq   #47,d0
        movl    #100,a0
        moveq   #1,d1
        movl    4(sp),a1
        trap    #9
        bccs    1$
        jmp     cerror
1$:
        clrl    d0
        rts
</programlisting></para>

<para>
Put this in the file <filename>seteuid.s</filename>:
</para>

<para><programlisting>
        .globl  _seteuid
_seteuid:
        moveq   #47,d0
        movl    #100,a0
        moveq   #0,d1
        movl    4(sp),a1
        trap    #9
        bccs    1$
        jmp     cerror
1$:
        clrl    d0
        rts
</programlisting></para>

<para>
After creating the files, you then assemble them using
</para>

<screen>
&prompt;<userinput>as seteuid.s</userinput>
&prompt;<userinput>as setegid.s</userinput>
</screen>

<para>
which should produce the files <filename>seteuid.o</filename> and
<filename>setegid.o</filename>.
</para>

<para>
Next you need to add these to the LIBSM line in the DNIX section of
the Samba Makefile. Your LIBSM line will look something like this:
</para>

<para><programlisting>
LIBSM = setegid.o seteuid.o -ln
</programlisting></para>

<para>
You should then remove the line:
</para>

<para><programlisting>
#define NO_EID
</programlisting></para>

<para>from the DNIX section of <filename>includes.h</filename>.</para>

</sect1>

<sect1>
<title>Red Hat Linux</title>

<para>
By default during installation, some versions of Red Hat Linux add an
entry to <filename>/etc/hosts</filename> as follows:
<programlisting>
127.0.0.1 loopback "hostname"."domainname"
</programlisting>
</para>

<para>
<indexterm><primary>loopback interface</primary></indexterm>
This causes Samba to loop back onto the loopback interface.
The result is that Samba fails to communicate correctly with
the world and therefore may fail to correctly negotiate who
is the master browse list holder and who is the master browser.
</para>

<para>
Corrective action: Delete the entry after the word "loopback"
in the line starting 127.0.0.1.
</para>
</sect1>

<sect1>
<title>AIX: Sequential Read Ahead</title>
<!-- From an email by William Jojo <jojowil@hvcc.edu> -->
<para>
Disabling sequential read ahead can improve Samba performance significantly
when there is a relatively high level of multiprogramming (many smbd processes
or mixed with another workload), not an abundance of physical memory or slower
disk technology. These can cause AIX to have a higher WAIT values. Disabling
sequential read-ahead can also have an adverse affect on other workloads in the
system so you will need to evaluate other applications for impact.
</para>

<para>
It is recommended to use the defaults provided by IBM, but if you experience a
high amount of wait time, try disabling read-ahead with the following commands:
</para>

<para>
For AIX 5.1 and earlier: <userinput>vmtune -r 0</userinput>
</para>

<para>
For AIX 5.2 and later jfs filesystems: <userinput>ioo -o minpgahead=0</userinput>
</para>

<para>
For AIX 5.2 and later jfs2 filesystems: <userinput>ioo -o j2_minPageReadAhead=0</userinput>
</para>

<para>
If you have a mix of jfs and jfs2 filesystems on the same host, simply use both
ioo commands.
</para>
</sect1>

<sect1>
<title>Solaris</title>

<sect2>
<title>Locking Improvements</title>

<para>Some people have been experiencing problems with F_SETLKW64/fcntl 
when running Samba on Solaris. The built-in file-locking mechanism was
not scalable. Performance would degrade to the point where processes would
get into loops of trying to lock a file. It would try a lock, then fail,
then try again. The lock attempt was failing before the grant was
occurring. The visible manifestation of this was a handful of
processes stealing all of the CPU, and when they were trussed, they would
be stuck in F_SETLKW64 loops.
</para>

<para>
Please check with Sun support for current patches needed to fix this bug.
The patch revision for 2.6 is 105181-34, for 8 is 108528-19, and for 9 is 112233-04.
After the installation of these patches, it is recommended to reconfigure
and rebuild Samba.
</para>

<para>Thanks to Joe Meslovich for reporting this.</para>

</sect2>

<sect2 id="winbind-solaris9">
<title>Winbind on Solaris 9</title>
<para>
Nsswitch on Solaris 9 refuses to use the Winbind NSS module. This behavior
is fixed by Sun in patch <ulink
url="http://sunsolve.sun.com/search/advsearch.do?collection=PATCH&amp;type=collections&amp;max=50&amp;language=en&amp;queryKey5=112960;rev=14&amp;toDocument=yes">112960-14</ulink>.
</para>
</sect2>
</sect1>

</chapter>