0000706: require subshell environment to have its own copy of ulimit

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Category

Severity

Type

Date Submitted

Last Update

0000706

[1003.1(2013)/Issue7+TC1] Shell and Utilities

Objection

Enhancement Request

2013-05-31 20:35

2019-06-10 08:55

Reporter

jilles

View Status

public

Assigned To

Priority

normal

Resolution

Accepted

Status

Closed

Name

Jilles Tjoelker

Organization

FreeBSD

User Reference

Section

XCU 2.12

Page Number

2353

Line Number

74972

Interp Status

Approved

Final Accepted Text

See Note: 0001653.

Summary

0000706: require subshell environment to have its own copy of ulimit

Description

Users/scripts may expect that a ulimit command in a subshell environment does not affect any parent shell environment, like a cd or umask command. In fact, this is the case even in ksh93 which explicitly forks when a non-fork subshell environment tries to change ulimit. If the subshell environment is implemented via fork() or if the parent environment cannot execute any more commands, changes to ulimit do not affect the parent either.

Some historical non-compliant implementations execute command substitutions invoking a single built-in utility in the current shell environment. Apart from the fact that this is non-compliant for other reasons, a lone ulimit command with a new value in a command substitution is also unlikely to occur in practice because there is normally no code to run with the new limit and such a command generates no output.

Desired Action

Add a new entry to the list "A shell execution environment consists of the following:", under [XSI] shading:

* File size limit as set by ulimit.

Tags

tc2-2008

Attached Files

Relationships

Notes
(0001653) Don Cragun (manager) 2013-06-13 16:09	Interpretation response ------------------------ The standard states the requirements for subshell execution environments, and conforming implementations must conform to this. However, concerns have been raised about this which are being referred to the sponsor. Rationale: ------------- The current standard does not match historic (and desired) practice. Notes to the Editor (not part of this interpretation): ------------------------------------------------------- Make the changes suggested in the Desired Action.

(0001808) ajosey (manager) 2013-09-06 04:54	Interpretation Proposed 6 Sep 2013

(0001901) ajosey (manager) 2013-10-14 13:10	Interpretation approved 14 October 2013

Issue History
Date Modified	Username	Field	Change
2013-05-31 20:35	jilles	New Issue
2013-05-31 20:35	jilles	Name	=> Jilles Tjoelker
2013-05-31 20:35	jilles	Organization	=> FreeBSD
2013-05-31 20:35	jilles	Section	=> XCU 2.12
2013-05-31 20:35	jilles	Page Number	=> 2353
2013-05-31 20:35	jilles	Line Number	=> 74972
2013-06-13 16:09	Don Cragun	Interp Status	=> ---
2013-06-13 16:09	Don Cragun	Final Accepted Text	=> See Note: 0001653.
2013-06-13 16:09	Don Cragun	Note Added: 0001653
2013-06-13 16:09	Don Cragun	Status	New => Interpretation Required
2013-06-13 16:09	Don Cragun	Resolution	Open => Accepted
2013-06-13 16:10	Don Cragun	Tag Attached: tc2-2008
2013-06-13 16:11	Don Cragun	Interp Status	--- => Pending
2013-09-06 04:54	ajosey	Interp Status	Pending => Proposed
2013-09-06 04:54	ajosey	Note Added: 0001808
2013-10-14 13:10	ajosey	Interp Status	Proposed => Approved
2013-10-14 13:10	ajosey	Note Added: 0001901
2019-06-10 08:55	agadmin	Status	Interpretation Required => Closed

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