Bug 443889
| Summary: | getopts function does not work properly when used in a function that is invoked with back quotes | ||
|---|---|---|---|
| Product: | Red Hat Enterprise Linux 5 | Reporter: | Serge Bonin <serge.bonin> |
| Component: | ksh | Assignee: | Michal Hlavinka <mhlavink> |
| Status: | CLOSED ERRATA | QA Contact: | |
| Severity: | medium | Docs Contact: | |
| Priority: | low | ||
| Version: | 5.1 | CC: | rvokal, syeghiay |
| Target Milestone: | rc | ||
| Target Release: | --- | ||
| Hardware: | x86_64 | ||
| OS: | Linux | ||
| Whiteboard: | |||
| Fixed In Version: | Doc Type: | Bug Fix | |
| Doc Text: | Story Points: | --- | |
| Clone Of: | Environment: | ||
| Last Closed: | 2009-09-02 09:11:32 UTC | Type: | --- |
| Regression: | --- | Mount Type: | --- |
| Documentation: | --- | CRM: | |
| Verified Versions: | Category: | --- | |
| oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |
| Cloudforms Team: | --- | Target Upstream Version: | |
| Embargoed: | |||
There is one thing I don't understand in the function body: OPTIND=1 What's this line good for? OPTIND is set automatically by the shell... The behaviour is otherwise quite interesting... I don't know if it's a bug or if changing OPTIND value explicitly couldn't erase it's special meaning (unsetting it does). Thanks to your help in my issue reported in bug #431448, the problem goes away when I use the 'function test_function' format instead of 'test_function()'. I believe this changes the scope of the variables used by getopts in the function. This used to work in ksh88 but it changed in ksh93. I did have to remove the OPTIND=1 in the test_function for this to work under ksh. However, the reason I had it there in the first place, which used to work under ksh88, is that bash does not work properly if it isn't there. I can demonstrate this, if a call the test_function in this sequence: echo "Executing function:" echo " First call" test_function -c -i arg1 -iarg2 call1 echo " Second call" RET=`test_function -c -i arg1 -iarg2 call2` echo "$RET" echo " Third call" RET=`test_function -c -i arg1 -iarg2 call3` echo "$RET" echo " Forth call" test_function -c -i arg1 -iarg2 call4 This is the result of ksh using the 'function test_function' format without OPTIND: The following should always give the same result: Executing function: First call *** Function received argument -c *** Function received argument -i arg1 *** Function received argument -i arg2 OPTIND: 5 ARGS: -c -i arg1 -iarg2 call1 Any remaining argument in function call: call1 Second call *** Function received argument -c *** Function received argument -i arg1 *** Function received argument -i arg2 OPTIND: 5 ARGS: -c -i arg1 -iarg2 call2 Any remaining argument in function call: call2 Third call *** Function received argument -c *** Function received argument -i arg1 *** Function received argument -i arg2 OPTIND: 5 ARGS: -c -i arg1 -iarg2 call3 Any remaining argument in function call: call3 Forth call *** Function received argument -c *** Function received argument -i arg1 *** Function received argument -i arg2 OPTIND: 5 ARGS: -c -i arg1 -iarg2 call4 Any remaining argument in function call: call4 We now see that the getopts function is reacting normally on multiple calls. If I run the same thing with bash, I get: The following should always give the same result: Executing function: First call *** Function received argument -c *** Function received argument -i arg1 *** Function received argument -i arg2 OPTIND: 5 ARGS: -c -i arg1 -iarg2 call1 Any remaining argument in function call: call1 Second call OPTIND: 5 ARGS: -c -i arg1 -iarg2 call2 Any remaining argument in function call: call2 Third call OPTIND: 5 ARGS: -c -i arg1 -iarg2 call3 Any remaining argument in function call: call3 Forth call OPTIND: 5 ARGS: -c -i arg1 -iarg2 call4 Any remaining argument in function call: call4 As we see, OPTIND seems to be set to the value of the previous call to getopts. If I put back the OPTIND=1 statement before the getopts function and re-execute it in bash, I get the expected result: Executing function: First call *** Function received argument -c *** Function received argument -i arg1 *** Function received argument -i arg2 OPTIND: 5 ARGS: -c -i arg1 -iarg2 call1 Any remaining argument in function call: call1 Second call *** Function received argument -c *** Function received argument -i arg1 *** Function received argument -i arg2 OPTIND: 5 ARGS: -c -i arg1 -iarg2 call2 Any remaining argument in function call: call2 Third call *** Function received argument -c *** Function received argument -i arg1 *** Function received argument -i arg2 OPTIND: 5 ARGS: -c -i arg1 -iarg2 call3 Any remaining argument in function call: call3 Forth call *** Function received argument -c *** Function received argument -i arg1 *** Function received argument -i arg2 OPTIND: 5 ARGS: -c -i arg1 -iarg2 call4 Any remaining argument in function call: call4 If I execute the modified bash script in ksh, I don’t get the same result: The following should always give the same result: The following should always give the same result: Executing function: First call *** Function received argument -c *** Function received argument -i arg1 *** Function received argument -i arg2 OPTIND: 5 ARGS: -c -i arg1 -iarg2 call1 Any remaining argument in function call: call1 Second call *** Function received argument -c *** Function received argument -i arg1 *** Function received argument -i arg2 OPTIND: 5 ARGS: -c -i arg1 -iarg2 call2 Any remaining argument in function call: call2 Third call *** Function received argument -c *** Function received argument -i arg1 *** Function received argument -i arg2 OPTIND: 1 ARGS: -c -i arg1 -iarg2 call3 Any remaining argument in function call: -c -i arg1 -iarg2 call3 Forth call *** Function received argument -c *** Function received argument -i arg1 *** Function received argument -i arg2 OPTIND: 1 ARGS: -c -i arg1 -iarg2 call4 Any remaining argument in function call: -c -i arg1 -iarg2 call4 For some reason, ksh increments the value of OPTIND in the first and second call but stops doing it in the third and forth call to the function. If I put a typeset to the OPTIND variable in the test_function, none of the calls work in ksh but the all work well under bash. I just moved all of my scripts from ksh88 to bash as bash seems to be more compatible with the ‘mistakes’ I did in ksh88 (getopts and typeset local variables in function() name format) in respect to what is now done in ksh93. Do you believe that bash will also move in the direction that ksh93 has gone to or will bash continue to behave in this manner? Finally I'm sure that this is a bug. I've tried to patch it but without success yet. An advisory has been issued which should help the problem described in this bug report. This report is therefore being closed with a resolution of ERRATA. For more information on therefore solution and/or where to find the updated files, please follow the link below. You may reopen this bug report if the solution does not work for you. http://rhn.redhat.com/errata/RHBA-2009-1256.html |
From Bugzilla Helper: User-Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.1; .NET CLR 1.1.4322; .NET CLR 2.0.50727; .NET CLR 3.0.04506.30) Description of problem: The getopts function does not seem to work properly when used in a function that is invoked with back quotes. The OPTIND variable is not incremented on subsequent calls to the getopts function; only the first call works properly. Also, the getopts function stops recognizing arguments after subsequent calls to getopts using back quotes. Version-Release number of selected component (if applicable): ksh-20060214-1.4 How reproducible: Always Steps to Reproduce: Let's say we define a function using getopts as follows: #!/bin/ksh test_function() { typeset COMM_LCL_OPTION OPTIND=1 while getopts :ci: COMM_LCL_OPTION; do case ${COMM_LCL_OPTION} in c) echo " *** Function received argument -c" ;; i) echo " *** Function received argument -i ${OPTARG}" ;; esac done echo " OPTIND: ${OPTIND}" echo " ARGS: ${*}" shift $((${OPTIND} - 1)) echo " Any remaining argument in function call: ${*}" } If this function is called as follows: echo "Executing function:" echo " First call" RET=`test_function -c -i arg1 -iarg2 call1` echo "$RET" echo " Second call" RET=`test_function -c -i arg1 -iarg2 call2` echo "$RET" The first call will execute properly but all subsequent will not increment the OPTIND variable as it should: Executing function: First call *** Function received argument -c *** Function received argument -i arg1 *** Function received argument -i arg2 OPTIND: 5 ARGS: -c -i arg1 -iarg2 call1 Any remaining argument in function call: call1 Second call *** Function received argument -c *** Function received argument -i arg1 *** Function received argument -i arg2 OPTIND: 1 ARGS: -c -i arg1 -iarg2 call2 Any remaining argument in function call: -c -i arg1 -iarg2 call2 If this function is called directly instead of using back quotes, the results are in line with what is expected: echo "Executing function directly:" echo " First call" test_function -c -i arg1 -iarg2 call1 echo "$RET" echo " Second call" test_function -c -i arg1 -iarg2 call2 echo "$RET" As seen in the output, the OPTIND variable is properly incremented: Executing functioni directly: First call *** Function received argument -c *** Function received argument -i arg1 *** Function received argument -i arg2 OPTIND: 5 ARGS: -c -i arg1 -iarg2 call1 Any remaining argument in function call: call1 Second call *** Function received argument -c *** Function received argument -i arg1 *** Function received argument -i arg2 OPTIND: 5 ARGS: -c -i arg1 -iarg2 call2 Any remaining argument in function call: call2 However, if a call is made to the function with back quotes first and then directly to the function: echo "Executing function:" echo " First call" RET=`test_function -c -i arg1 -iarg2 call1` echo "$RET" echo " Second call" test_function -c -i arg1 -iarg2 call2 echo "$RET" The getopts function does not work properly on subsequent calls, even if these calls are directly done to the function: Executing function: First call *** Function received argument -c *** Function received argument -i arg1 *** Function received argument -i arg2 OPTIND: 5 ARGS: -c -i arg1 -iarg2 call1 Any remaining argument in function call: call1 Second call *** Function received argument -c *** Function received argument -i arg1 *** Function received argument -i arg2 OPTIND: 1 ARGS: -c -i arg1 -iarg2 call2 Any remaining argument in function call: -c -i arg1 -iarg2 call2 However, this does not seem to affect sub scripts that are called after a back quoted function: echo "Executing sub program:" echo " First call" RET=`test_function -c -i arg1 -iarg2 call1` echo "$RET" echo " Second call" RET=`test_function -c -i arg1 -iarg2 call2` echo "$RET" echo " Third call" RET=`./check_sub_getopts.ksh -c -i arg1 -iarg2 call3` echo "$RET" The check_sub_getopts.ksh script contains the exact same code as the test_function function stated above. The result is as follows: Executing sub program: First call *** Function received argument -c *** Function received argument -i arg1 *** Function received argument -i arg2 OPTIND: 5 ARGS: -c -i arg1 -iarg2 call1 Any remaining argument in function call: call1 Second call *** Function received argument -c *** Function received argument -i arg1 *** Function received argument -i arg2 OPTIND: 1 ARGS: -c -i arg1 -iarg2 call2 Any remaining argument in function call: -c -i arg1 -iarg2 call2 Third call *** Function received argument -c *** Function received argument -i arg1 *** Function received argument -i arg2 OPTIND: 5 ARGS: -c -i arg1 -iarg2 call3 Any remaining argument in function call: call3 This script was tested on OSF1, AIX, Solaris, and Unix services for Windows. On all of these OSs the getopts functions would increment the OPTIND variable correctly (its value would go up to 5 on each call to the test_function using back quotes or calling it directly). After further testing, I had discovered that it is not only the OPTIND variable that is not properly incremented, but the getopts function does not even detect arguments anymore. This can be seen with the following calls: echo "Executing function:" echo " First call" test_function -c -i arg1 -iarg2 call1 echo " Second call" RET=`test_function -c -i arg1 -iarg2 call2` echo "$RET" echo " Third call" test_function -c -i arg1 -iarg2 call3 echo " Forth call" RET=`test_function -c -i arg1 -iarg2 call4` echo "$RET" echo " Fifth call" RET=`./check_sub_getopts.ksh -c -i arg1 -iarg2 call5` echo "$RET" The output is: Executing function: First call *** Function received argument -c *** Function received argument -i arg1 *** Function received argument -i arg2 OPTIND: 5 ARGS: -c -i arg1 -iarg2 call1 Any remaining argument in function call: call1 Second call *** Function received argument -c *** Function received argument -i arg1 *** Function received argument -i arg2 OPTIND: 5 ARGS: -c -i arg1 -iarg2 call2 Any remaining argument in function call: call2 Third call OPTIND: 1 ARGS: -c -i arg1 -iarg2 call3 Any remaining argument in function call: -c -i arg1 -iarg2 call3 Forth call OPTIND: 1 ARGS: -c -i arg1 -iarg2 call4 Any remaining argument in function call: -c -i arg1 -iarg2 call4 Fifth call *** Function received argument -c *** Function received argument -i arg1 *** Function received argument -i arg2 OPTIND: 5 ARGS: -c -i arg1 -iarg2 call5 Any remaining argument in function call: call5 We can see that in the third and forth call, no matter if the function was called directly or with back quotes, the getopts function does not even detected the presence of the -c and -i arguments. Good news is that at least the external shell has the correct getopts info (fifth call). If I run the exact same script in bash, I do not get the same result: Executing function: First call *** Function received argument -c *** Function received argument -i arg1 *** Function received argument -i arg2 OPTIND: 5 ARGS: -c -i arg1 -iarg2 call1 Any remaining argument in function call: call1 Second call *** Function received argument -c *** Function received argument -i arg1 *** Function received argument -i arg2 OPTIND: 5 ARGS: -c -i arg1 -iarg2 call2 Any remaining argument in function call: call2 Third call *** Function received argument -c *** Function received argument -i arg1 *** Function received argument -i arg2 OPTIND: 5 ARGS: -c -i arg1 -iarg2 call3 Any remaining argument in function call: call3 Forth call *** Function received argument -c *** Function received argument -i arg1 *** Function received argument -i arg2 OPTIND: 5 ARGS: -c -i arg1 -iarg2 call4 Any remaining argument in function call: call4 Fifth call *** Function received argument -c *** Function received argument -i arg1 *** Function received argument -i arg2 OPTIND: 5 ARGS: -c -i arg1 -iarg2 call5 Any remaining argument in function call: call5 As we can see, in bash, the OPTIND and arguments seem to be processed correctly. Actual Results: Results of the last test: Executing function: First call *** Function received argument -c *** Function received argument -i arg1 *** Function received argument -i arg2 OPTIND: 5 ARGS: -c -i arg1 -iarg2 call1 Any remaining argument in function call: call1 Second call *** Function received argument -c *** Function received argument -i arg1 *** Function received argument -i arg2 OPTIND: 5 ARGS: -c -i arg1 -iarg2 call2 Any remaining argument in function call: call2 Third call OPTIND: 1 ARGS: -c -i arg1 -iarg2 call3 Any remaining argument in function call: -c -i arg1 -iarg2 call3 Forth call OPTIND: 1 ARGS: -c -i arg1 -iarg2 call4 Any remaining argument in function call: -c -i arg1 -iarg2 call4 Fifth call *** Function received argument -c *** Function received argument -i arg1 *** Function received argument -i arg2 OPTIND: 5 ARGS: -c -i arg1 -iarg2 call5 Any remaining argument in function call: call5 Expected Results: What is expected: Executing function: First call *** Function received argument -c *** Function received argument -i arg1 *** Function received argument -i arg2 OPTIND: 5 ARGS: -c -i arg1 -iarg2 call1 Any remaining argument in function call: call1 Second call *** Function received argument -c *** Function received argument -i arg1 *** Function received argument -i arg2 OPTIND: 5 ARGS: -c -i arg1 -iarg2 call2 Any remaining argument in function call: call2 Third call *** Function received argument -c *** Function received argument -i arg1 *** Function received argument -i arg2 OPTIND: 5 ARGS: -c -i arg1 -iarg2 call3 Any remaining argument in function call: call3 Forth call *** Function received argument -c *** Function received argument -i arg1 *** Function received argument -i arg2 OPTIND: 5 ARGS: -c -i arg1 -iarg2 call4 Any remaining argument in function call: call4 Fifth call *** Function received argument -c *** Function received argument -i arg1 *** Function received argument -i arg2 OPTIND: 5 ARGS: -c -i arg1 -iarg2 call5 Any remaining argument in function call: call5 Additional info: This bug was entered on http://bugs.centos.org/view.php?id=2803 and they refered it to this site.