getpagesize / libsysfs broken with 0.148

[Hannes Reinecke <hare@suse.de>]

[-- Attachment #1: Type: text/plain, Size: 1153 bytes --]

Hi all,

the implementation of getpagesize() is broken in klibc.

klibc uses sysinfo.mem_unit, which linux interpretes as the memory unit 
all other memory values returned are to be multiplied with.
So it's perfectly ok for the linux sysinfo() to return a mem_unit of 
'1', which is does if the memory available for this machine fits into 
the counter.
For the unbelievers, have a look in kernel/timer.c:sys_sysinfo().

As a quick hack I've added a check for mem_unit==1 and reset the 
page_size to 4096 on those cases.

Naturally, this is not the right fix. The right fix would be to get the 
values from the kernel headers and/or some magic juju for those machines 
with variable pagesize.

It probably would not have been noticed, but as libsysfs insists on 
doing all reads from sysfs attributes with a length of pagesize, the 
failures were ... interesting.

So in short, udev does _not_ work with klibc until that (or an 
equivalent) patch is applied.

Cheers,

Hannes
-- 
Dr. Hannes Reinecke			hare@suse.de
SuSE Linux AG				S390 & zSeries
Maxfeldstraße 5				+49 911 74053 688
90409 Nürnberg				http://www.suse.de

[-- Attachment #2: klibc-0.148-getpagesize.patch --]
[-- Type: text/x-patch, Size: 384 bytes --]

--- klibc-0.148/klibc/getpagesize.c.orig	2004-07-07 11:56:31.000000000 +0200
+++ klibc-0.148/klibc/getpagesize.c	2004-07-15 10:32:32.749143222 +0200
@@ -20,5 +20,6 @@
   if ( rv == -1 )
     return -1;
 
-  return (page_size = si.mem_unit);
+  /* sysinfo returns 1 for mem_unit in some cases, so default to 4096. */
+  return (page_size = (si.mem_unit == 1 ? 4096 : si.mem_unit));
 }