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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