+++ This bug was initially created as a clone of Bug #596823 +++

Created an attachment (id=417276)
Syntax error fix for /etc/sysconfig/network-scripts/ifup-ib from openib-1.4.1-5.el5

Description of problem:

There is a syntax error in /etc/sysconfig/network-scripts/ifup-ib which
causes the following boot process error message during Infiniband interface initialization:

ifup-ib: line 79: [: too many arguments

The problem is that bash's "-a" (AND) operator is not evaluated lazily i.e. the following construct in ifup-ib does not work correctly if the MTU variable is unset/empty:

        # cap the MTU where we should based upon mode
        if [ -n "${MTU}" -a $MTU -gt 2044 ]; then
            MTU=2044
        fi

This alternative works because the && operator is evaluated lazily:

        # cap the MTU where we should based upon mode
        if [ -n "${MTU}" ] && [ $MTU -gt 2044 ]; then
            MTU=2044
        fi

Another alternative would be this

        # cap the MTU where we should based upon mode
        if [ -n "${MTU}" ]; then
            if [ $MTU -gt 2044 ]; then
                MTU=2044
            fi
        fi

I've attached a patch which fixes the two occurrences of this construct in ifup-ib.

Version-Release number of selected component (if applicable):

# rpm -q openib
openib-1.4.1-5.el5

How reproducible:

Boot a system with an active IB interface which has not MTU
configured explicitly in /etc/sysconfig/network-scripts/ifcfg-ib0.

Steps to Reproduce:
1. Configure an ib0 interface without setting MTU in /etc/sysconfig/network-scripts/ifcfg-ib0
2. Boot the system
3. Watch for the error messages during ib0 interface initialization.
  
Actual results:

ifup-ib: line 79: [: too many arguments

Expected results:

No error message

Additional info:

Test cases:

$ cat MTU-old.sh
#!/bin/bash                                      

MTU=""
if [ -n "${MTU}" -a $MTU -gt 2044 ]; then
        echo 1a                          
else                                     
        echo 1b                          
fi                                       

MTU="2000"
if [ -n "${MTU}" -a $MTU -gt 2044 ]; then
        echo 2a                          
else                                     
        echo 2b                          
fi

MTU="3000"
if [ -n "${MTU}" -a $MTU -gt 2044 ]; then
        echo 3a
else
        echo 3b
fi

$ cat MTU-new.sh
#!/bin/bash

MTU=""
if [ -n "${MTU}" ] && [ $MTU -gt 2044 ]; then
        echo 1a
else
        echo 1b
fi

MTU="2000"
if [ -n "${MTU}" ] && [ $MTU -gt 2044 ]; then
        echo 2a
else
        echo 2b
fi

MTU="3000"
if [ -n "${MTU}" ] && [ $MTU -gt 2044 ]; then
        echo 3a
else
        echo 3b
fi

Test results:

$ ./MTU-old.sh
./MTU-old.sh: line 4: [: too many arguments
1b
2b
3a
$ ./MTU-new.sh
1b
2b
3a