08-11-2009
More information
I have tracked this issue to being something about memory locking over NFS. As soon as the process goes to mlockall, we update the modification time on the shared library. And if the shared library is read only, we get a Page I/O modification error. If I put the libraries local to the machine, it doesn't happen. So it seems to be some sort of NFS conflict. Has anyone seen this type of thing before?
---------- Post updated at 05:51 PM ---------- Previous update was at 06:35 AM ----------
found I was able to reproduce the symptom with just a hello world type of app.
#include <stdio.h>
#include <stdlib.h>
#include <sys/mman.h>
void main()
{
mlockall(CTL_CURRENT)
printf("hello world\n");
}
linked by the following
cc hello_world.c -o hello_world -L/opt/mlib/lib/pa2.0 -lveclib -llapack -Wl,s+
our home directories are NFS mounted so if I copy pa2.0 to /home/mine/pa2.0 and check the timestamp then
change my SHLIB_PATH EV to point to /home/mine/pa2.0
the timestamps change from the original copy after I run hello_world.
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LEARN ABOUT OSX
redo_prebinding
REDO_PREBINDING(1) General Commands Manual REDO_PREBINDING(1)
NAME
redo_prebinding - redo the prebinding of an executable or dynamic library
SYNOPSIS
redo_prebinding [-c | -p | -d] [-i] [-z] [-u] [-r rootdir] [-e executable_path] [-seg_addr_table table_file_name] [-seg_addr_table_filename
pathname] [-seg1addr address] [-o output_file] [-s] input_file
DESCRIPTION
Redo_prebinding is used to redo the prebinding of an executable or dynamic library when one of the dependent dynamic libraries changes.
The input file, executable or dynamic library, must have initially been prebound for this program to redo the prebinding. Also all
depended libraries must have their prebinding up to date. So when redoing the prebinding for libraries they must be done in dependency
order. Also when building executables or dynamic libraries that are to be prebound (with the -prebind options to ld(1) or libtool(1)) the
dependent libraries must have their prebinding up to date or the result will not be prebound.
The options allow for different types of checking for use in shell scripts. Only one of -c, -p or -d can be used at a time. If redo_pre-
binding redoes the prebinding on an input file it will run /usr/bin/objcunique if it exists on the result.
OPTIONS
-c only check if the file needs to have it's prebinding redone and return status. A 0 exit means the file's prebinding is up to date,
1 means it needs to be redone and 2 means it could not be checked for reasons like a dependent library is missing (an error message
is printed in these cases).
-p check only for prebound files and return status. An exit status of 1 means the file is a Mach-O that could have been prebound and
is not otherwise the exit status is 0.
-d check only for dynamic shared library files and return status. An exit status of 0 means the file is a dynamic shared library, 1
means the file is not, 2 means there is some mix in the architectures.
-i ignore non-prebound files (useful when running on all types of files).
-z zero out the prebind check sum in the output if it has one.
-u unprebind, rather than reprebind (-c, -p, -d, -e ignored). Resets or removes prebinding-specific information from the input file.
As unprebinding is intended to produce a canonical Mach-O binary, bundles and non-prebound executables and dylibs are acceptable as
input. For these files, the unprebind operation will zero library time stamps and version numbers and zero entries in the two-
level hints table.
-e executable_path
replace any dependent library's "@executable_path" prefix with the executable_path argument.
-seg_addr_table table_file_name
The -seg_addr_table option is used when the input a dynamic library and if specified the table entry for the install_name of the
dynamic library is used for checking and the address to relocate the library to as it prefered address.
-seg_addr_table_filename pathname
Use pathname instead of the install name of the library for matching an entry in the segment address table.
-seg1addr address
Move the input library to base address address. This option does not apply when -u, -seg_addr_table or -seg_addr_table_filename are
specified.
-r rootdir
prepend the rootdir argument to all dependent libraries.
-o output_file
write the updated file into output_file rather than back into the input file.
-s write the updated file to standard output
DIAGNOSTICS
With no -c, -p or -d an exit status of 0 means success and 2 means it could not be done for reasons like a dependent library is missing (an
error message is printed in these cases). And exit of 3 is for the specific case when the dependent libraries are out of date with respect
to each other.
Apple Computer, Inc. March 29, 2004 REDO_PREBINDING(1)