Chapter 37. Portability

Chapter 37. Portability
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Jelmer R. Vernooij

The Samba Team

<jelmer@samba.org>

John H. Terpstra

Samba Team

<jht@samba.org>

Table of Contents

Sequential Read Ahead

Solaris

Locking Improvements
Winbind on Solaris 9

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.

HPUX

-HP's implementation of supplementary groups is non-standard (for -historical reasons). There are two group files, /etc/group and -/etc/logingroup; the system maps UIDs to numbers using the former, but -initgroups() reads the latter. Most system admins who know the ropes -symlink /etc/group to /etc/logingroup -(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 /etc/logingroup has what it considers to be an invalid -ID, which means outside the range [0..UID_MAX], where UID_MAX is (I think) -60000 currently on HP-UX. This precludes -2 and 65534, the usual nobody -GIDs. -

-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. -

This is documented in the HP manual pages under setgroups(2) and passwd(4). -

-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. -

SCO UNIX

-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. -

-The patch you need is UOD385 Connection Drivers SLS. It is available from -SCO (ftp.sco.com, directory SLS, -files uod385a.Z and uod385a.ltr.Z). -

-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. -

DNIX

-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. -

-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. -

-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 setegid.s: -

-        .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
-

-Put this in the file seteuid.s: -

-        .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
-

-After creating the above files, you then assemble them using -

-$ as seteuid.s
-$ as setegid.s
-

-that should produce the files seteuid.o and -setegid.o -

-Then you need to add these to the LIBSM line in the DNIX section of -the Samba Makefile. Your LIBSM line will then look something like this: -

-LIBSM = setegid.o seteuid.o -ln
-

-You should then remove the line: -

-#define NO_EID
-

from the DNIX section of includes.h.

Red Hat Linux

-By default during installation, some versions of Red Hat Linux add an -entry to /etc/hosts as follows: -

-	127.0.0.1 loopback "hostname"."domainname"
-

-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. -

-Corrective Action: Delete the entry after the word "loopback" -in the line starting 127.0.0.1. -

AIX

Sequential Read Ahead

-Disabling Sequential Read Ahead using vmtune -r 0 improves -Samba performance significantly. -

Solaris

Locking Improvements

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. So the visible manifestation of this would be a handful of -processes stealing all of the CPU, and when they were trussed they would -be stuck if F_SETLKW64 loops. -

-Sun released patches for Solaris 2.6, 8, and 9. The patch for Solaris 7 -has not been released yet. -

-The patch revision for 2.6 is 105181-34, for 8 is 108528-19 and for 9 is 112233-04. -

-After the install of these patches, it is recommended to reconfigure -and rebuild Samba. -

Thanks to Joe Meslovich for reporting this.

Winbind on Solaris 9

-Nsswitch on Solaris 9 refuses to use the Winbind NSS module. This behavior -is fixed by Sun in patch 113476-05, which as of March 2003, is not in any -roll-up packages. -

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