[augeas-devel] [Augeas] #47: Use 'domain' field as node name in limits.conf lens

[Augeas]

#47: Use 'domain' field as node name in limits.conf lens
------------------------------+---------------------------------------------
 Reporter:  markdrayton       |       Owner:  lutter
     Type:  enhancement       |      Status:  new   
 Priority:  minor             |   Milestone:  next  
Component:  Augeas            |     Version:  0.4.1 
 Keywords:  limits.conf lens  |  
------------------------------+---------------------------------------------
 limits.conf has 4 whitespace-separated fields:

 `domain type item value`

 e.g.

 `@student - maxlogins 4`

 limits users in the student group to a maximum of 4 logins.

 Currently the domain field is used as the Augeas node name:

 {{{
 /files/etc/security/limits.conf/@student
 /files/etc/security/limits.conf/@student/type = "-"
 /files/etc/security/limits.conf/@student/item = "maxlogins"
 /files/etc/security/limits.conf/@student/value = "4"
 }}}

 But the domain can be *. `print /files/etc/security/limits.conf/*` prints
 all nodes, because * matches all of them. dlutter says escaping the * with
 a backslash works but I can't persuade that into working:

 {{{
 [16:09:13] <lutter> raphink: you can escape any character in a path
 expression with a backslash, so /foo/bar/\* matches the '*'
 }}}

 {{{
 augtool> print /files/etc/security/limits.conf/\*/
 augtool>
 }}}

 Maybe that doesn't work in my version (0.3.6). I can only see the * entry
 by using a * as the node, which of course matches all:

 {{{
 /files/etc/security/limits.conf/#comment[1] = "foo"
 /files/etc/security/limits.conf/#comment[2] = "blah"
 /files/etc/security/limits.conf/@student
 /files/etc/security/limits.conf/@student/type = "-"
 /files/etc/security/limits.conf/@student/item = "maxlogins"
 /files/etc/security/limits.conf/@student/value = "4"
 /files/etc/security/limits.conf/*
 /files/etc/security/limits.conf/*/type = "-"
 /files/etc/security/limits.conf/*/item = "nofile"
 /files/etc/security/limits.conf/*/value = "16384"
 }}}

 I can't add a new node:

 {{{
 augtool> ins * after /files/etc/security/limits.conf/*[last()]
 Failed
 }}}

 raphink on #augeas helped me (thanks!) with a simple patch to set the node
 name to domain, which avoids a literal * being in the tree:

 {{{
 /files/etc/security/limits.conf/#comment[39] = "foo"
 /files/etc/security/limits.conf/#comment[40] = "blah"
 /files/etc/security/limits.conf/domain[1] = "@student"
 /files/etc/security/limits.conf/domain[1]/type = "-"
 /files/etc/security/limits.conf/domain[1]/item = "maxlogins"
 /files/etc/security/limits.conf/domain[1]/value = "4"
 /files/etc/security/limits.conf/domain[2] = "*"
 /files/etc/security/limits.conf/domain[2]/type = "-"
 /files/etc/security/limits.conf/domain[2]/item = "nofile"
 /files/etc/security/limits.conf/domain[2]/value = "16384"
 }}}

 Now setting:

 {{{
 augtool> set /files/etc/security/limits.conf/domain[last()] "*"
 augtool> set /files/etc/security/limits.conf/domain[last()]/type "soft"
 augtool> set /files/etc/security/limits.conf/domain[last()]/item "core"
 augtool> set /files/etc/security/limits.conf/domain[last()]/value "0"
 augtool> print /files/etc/security/limits.conf/
 [..]
 /files/etc/security/limits.conf/domain[3] = "*"
 /files/etc/security/limits.conf/domain[3]/type = "soft"
 /files/etc/security/limits.conf/domain[3]/item = "core"
 /files/etc/security/limits.conf/domain[3]/value = "0"
 }}}

 Patch and new test attached. Diff'ed against 0.3.6 but neither of these
 files is different to the ones currently in the Git repo.

-- 
Ticket URL: <https://fedorahosted.org/augeas/ticket/47>
Augeas <http://augeas.net/>
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