openssh unix dev - Jun 2001 - wtmpx problem on Solaris 8 sparcv9 (64bit) environment

Hello

When I was using OpenSSH-2.9p2 in Solaris 8 sparcv9 (64bit)
environment, I found some trouble that wtmpx has broken.

The size of utmpx structure object becomes larger than 32 bit environment 
in sparcv9 environment.Therefore, instead of using utmpx structure object, 
using futmpx structure object is better.
In sparcv9 environment, futmpx structure object is used instead of utmpx 
structure object.


The system is as follows.
	OpenSSH Version: 2.9p2
	OS:
	% uname -a
	SunOS foo 5.8 Generic_108528-06 sun4u sparc SUNW,UltraSPARC-IIi-cEngine
	% isainfo -v 
	64-bit sparcv9 applications
	32-bit sparc applications


Please look at reference.
% cat utmptest.c 
#include <stdio.h>
#include <utmp.h>
#include <utmpx.h>

main ()
{
    struct utmp utmp;
    struct futmp futmp;
    struct utmpx utmpx;
    struct futmpx futmpx;

    printf("utmp: %d, futmp: %d / utmpx: %d, futmpx: %d\n",
        sizeof(utmp), sizeof(futmp), sizeof(utmpx), sizeof(futmpx));
    return(1);
}
% cc utmptest.c
% ./a.out
utmp: 36, futmp: 36 / utmpx: 372, futmpx: 372
% cc -xarch=v9 utmptest.c
% ./a.out
utmp: 40, futmp: 36 / utmpx: 384, futmpx: 372



Following are patch for "openssh-2.9p2/loginrec.c" file.

diff -Naur openssh-2.9p2.org/loginrec.c openssh-2.9p2.cast/loginrec.c
--- openssh-2.9p2.org/loginrec.c        Wed May  9 05:34:33 2001
+++ openssh-2.9p2.cast/loginrec.c       Thu Jun 28 11:06:22 2001
@@ -887,7 +891,11 @@
 /* write a utmpx entry with the system's help (pututxline() and pals) */
 # ifdef UTMPX_USE_LIBRARY
 static int
+#ifdef __sparcv9
+utmpx_write_library(struct logininfo *li, struct utmpx *utx)
+#else
 utmpx_write_library(struct logininfo *li, struct utmpx *utx)
+#endif
 {
        setutxent();
        pututxline(utx);
@@ -902,7 +910,11 @@

 /* write a utmp entry direct to the file */
 static int
+#ifdef __sparcv9
+utmpx_write_direct(struct logininfo *li, struct futmpx *utx)
+#else
 utmpx_write_direct(struct logininfo *li, struct utmpx *utx)
+#endif
 {
        log("utmpx_write_direct: not implemented!");
        return 0;
@@ -1144,7 +1156,11 @@
 /* write a wtmpx entry direct to the end of the file */
 /* This is a slight modification of code in OpenBSD's logwtmp.c */
 static int
+#ifdef __sparcv9
+wtmpx_write(struct logininfo *li, struct futmpx *utx)
+#else
 wtmpx_write(struct logininfo *li, struct utmpx *utx)
+#endif
 {
        struct stat buf;
        int fd, ret = 1;
@@ -1167,6 +1183,24 @@
        return ret;
 }

+#ifdef __sparcv9
+void
+utmpx_to_futmpx(struct utmpx *utx, struct futmpx *futx)
+{
+       strncpy(futx->ut_user, utx->ut_user, sizeof(futx->ut_user));
+       strncpy(futx->ut_id, utx->ut_id, sizeof(futx->ut_id));
+       strncpy(futx->ut_line, utx->ut_line, sizeof(futx->ut_line));
+       futx->ut_pid                = (pid32_t)utx->ut_pid;
+       futx->ut_type               = (int16_t)utx->ut_type;
+       futx->ut_exit.e_termination = (int16_t)utx->ut_exit.e_termination;
+       futx->ut_exit.e_exit        = (int16_t)utx->ut_exit.e_exit;
+       futx->ut_tv.tv_sec          = (time32_t)utx->ut_tv.tv_sec;
+       futx->ut_tv.tv_usec         = (int32_t)utx->ut_tv.tv_usec;
+       futx->ut_session            = (int32_t)utx->ut_session;
+       futx->ut_syslen             = (int16_t)utx->ut_syslen;
+       strncpy(futx->ut_host, utx->ut_host, sizeof(futx->ut_host));
+}
+#endif

 static int
 wtmpx_perform_login(struct logininfo *li)
@@ -1174,7 +1208,15 @@
        struct utmpx utx;

        construct_utmpx(li, &utx);
+#ifdef __sparcv9
+       {
+               struct futmpx futx;
+               utmpx_to_futmpx(&utx , &futx);
+               return wtmpx_write(li, &futx);
+       }
+#else
        return wtmpx_write(li, &utx);
+#endif
 }


@@ -1184,7 +1226,16 @@
        struct utmpx utx;

        construct_utmpx(li, &utx);
-       return wtmpx_write(li, &utx);
+#ifdef __sparcv9
+        {
+               struct futmpx futx;
+               utmpx_to_futmpx(&utx , &futx);
+               return wtmpx_write(li, &futx);
+        }
+#else
+        return wtmpx_write(li, &utx);
+#endif
+
 }


@@ -1207,7 +1258,11 @@

 /* Return true if this wtmpx entry indicates a login */
 static int
+#ifdef __sparcv9
+wtmpx_islogin(struct logininfo *li, struct futmpx *utx)
+#else
 wtmpx_islogin(struct logininfo *li, struct utmpx *utx)
+#endif
 {
        if ( strncmp(li->username, utx->ut_name,
                MIN_SIZEOF(li->username, utx->ut_name)) == 0 ) {
@@ -1226,7 +1281,11 @@
 wtmpx_get_entry(struct logininfo *li)
 {
        struct stat st;
+#ifdef __sparcv9
+       struct futmpx utx;
+#else
        struct utmpx utx;
+#endif
        int fd, found=0;

        /* Clear the time entries */
@@ -1245,7 +1304,11 @@
        }

        /* Seek to the start of the last struct utmpx */
+#ifdef __sparcv9
+       if (lseek(fd, (off_t)(0-sizeof(struct futmpx)), SEEK_END) == -1 ) {
+#else
        if (lseek(fd, (off_t)(0-sizeof(struct utmpx)), SEEK_END) == -1 ) {
+#endif
                /* probably a newly rotated wtmpx file */
                close(fd);
                return 0;
@@ -1275,7 +1338,11 @@
 # endif
                        continue;
                }
+#ifdef __sparcv9
+               if (lseek(fd, (off_t)(0-2*sizeof(struct futmpx)), SEEK_CUR) ==
-1) {
+#else
                if (lseek(fd, (off_t)(0-2*sizeof(struct utmpx)), SEEK_CUR) ==
-1) {
+#endif
                        close (fd);
                        return 0;
                }

>When I was using OpenSSH-2.9p2 in Solaris 8 sparcv9 (64bit)
>environment, I found some trouble that wtmpx has broken.
Why are you building 64bit binaries for ssh ?  This will gain you
nothing and there is no reason to do so.  32bit binaries run just fine
on a 64bit kernel (most of Solaris is still 32bit binaries even when
running a 64bit kernel).

There are currently only 4 reasons to compile userland binaries 64bit
rather than 32bit:

	1. The process needs greater than 4Gb address space 2. Need for
	a 64bit time_t
		ie need to process times past 2038 3. Direct access to
	kernel memory when runing a 64bit kernel 4. Need to control a
	64bit process via /proc (ie you are a debugger).

None of the ssh programs fall into these categories.

You can do 64bit maths without building a 64bit binary and you can get
UltraSPARC performance improvements on 32bit binaries - infact in
general 32bit binaries perform better than 64bit ones.

If you are compiling with -xarch=v9 in an attempt to gain the
performance benifits of the UltraSPARC platfrom then this isn't what
you are getting.  In fact all it will do is hurt your performance since
you will waste valuable cache space - bigger bits does NOT mean
faster.

-xarch=v9 means build a 64bit binary -xtarget=ultra will give you a
32bit binary optimized for UltraSPARC.

I don't believe that this patch is neccessary.


--
Darren J Moffat