Bug 1400371

Summary: oorexx execution of Linux pgrep command returns invalid results
Product: [Fedora] Fedora Reporter: Don Swaner <Gecko8211>
Component: oorexxAssignee: Gérard Milmeister <gemi>
Status: CLOSED EOL QA Contact: Fedora Extras Quality Assurance <extras-qa>
Severity: unspecified Docs Contact:
Priority: unspecified    
Version: 24CC: gemi
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Hardware: x86_64   
OS: Linux   
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Last Closed: 2017-08-08 19:23:21 UTC Type: Bug
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Description Don Swaner 2016-12-01 02:17:30 UTC
Description of problem:
When the pgrep command is executed by oorexx, the result is invalid.  (Note that pgrep is not an oorexx command, but a linux command.)

Version-Release number of selected component (if applicable):
oorexx-4.2.0-1.fc23.x86_64

How reproducible:
Always

Steps to Reproduce:
1.  From the bash command line, issue the following commands:
pgrep -f zort-zort
pgrep -f zort-zort | cat
Note that there is no output from either command (the nonexistent process zort-zort is not running).

2.  Run the commands:
rexx -e "'pgrep -f zort-zort'"
rexx -e "'pgrep -f zort-zort | cat'"

Note that for the first command, one invalid process ID is returned and for the
second, 2 invalid process IDs are returned.

3. If the pgrep commands are run implicitly from a rexx script:

#!/usr/bin/rexx
trace 'R'
"pgrep -f zort-zort"
"pgrep -f zort-zort | cat"
"pgrep -f zort-zort | rxqueue"
do while queued() > 0
    parse pull zans
    say zans
    "ps -F --pid "zans
end
exit

The results differ from item 2: zero or 1 invalid process IDs are returned.
(Note rxapi must be running to use rxqueue.)

Actual results:
Invalid process IDs are returned.

Expected results:
No process IDs are returned for a pgrep on non-existent processes.

Additional info:

Comment 1 Don Swaner 2016-12-01 21:53:32 UTC
If the "-c" or "--count" option is added to pgrep, from bash, "pgrep -c -f zort-zort | cat" displays the correct result: 0.  However, when run under oorexx, the result displayed is 1.  Now 1 is the return code from pgrep when no items are found (i.e. the count is zero), and the zero count is output on stdout (correctly, under bash).  Similary, under oorexx, when stdout of "pgrep -c -f zort-zort" is piped to rxqueue, then 1 is pulled from the queue (instead of the correct answer 0).

Comment 2 Don Swaner 2016-12-24 19:21:11 UTC
These invalid results also happen in F25 (same version of oorexx).  A work-around is to use "ps -A -o args | rxqueue" and parse the queued output for the target process.

Comment 3 Fedora End Of Life 2017-07-26 00:01:54 UTC
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Approximately 2 (two) weeks from now Fedora will stop maintaining
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Comment 4 Fedora End Of Life 2017-08-08 19:23:21 UTC
Fedora 24 changed to end-of-life (EOL) status on 2017-08-08. Fedora 24 is
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