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01/01: services: Add pam-limits-service.
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From: |
Ricardo Wurmus |
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Subject: |
01/01: services: Add pam-limits-service. |
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Date: |
Tue, 19 Jul 2016 21:50:23 +0000 (UTC) |
rekado pushed a commit to branch master
in repository guix.
commit 909147e43f8c9f8c9b9d33597d5dd83facca699c
Author: Ricardo Wurmus <address@hidden>
Date: Mon Oct 12 07:11:51 2015 +0200
services: Add pam-limits-service.
* gnu/system/pam.scm (<pam-limits-entry>): New record type.
(pam-limits-entry, pam-limits-entry->string): New procedures.
* gnu/services/base.scm (pam-limits-service-type): New variable.
(pam-limits-service): New procedure.
* doc/guix.texi (Base Services): Document it.
---
doc/guix.texi | 30 ++++++++++++++++++++++++
gnu/services/base.scm | 43 ++++++++++++++++++++++++++++++++++
gnu/system/pam.scm | 61 +++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 134 insertions(+)
diff --git a/doc/guix.texi b/doc/guix.texi
index 1c4d57c..7ea9ddf 100644
--- a/doc/guix.texi
+++ b/doc/guix.texi
@@ -17,6 +17,7 @@ Copyright @copyright{} 2015, 2016 Mathieu address@hidden
Copyright @copyright{} 2014 Pierre-Antoine address@hidden
Copyright @copyright{} 2015 Taylan Ulrich Bayırlı/address@hidden
Copyright @copyright{} 2015, 2016 Leo address@hidden
+Copyright @copyright{} 2015, 2016 Ricardo address@hidden
Copyright @copyright{} 2016 Ben address@hidden
Copyright @copyright{} 2016 Chris address@hidden
Copyright @copyright{} 2016 Efraim Flashner
@@ -7570,6 +7571,35 @@ to add @var{device} to the kernel's entropy pool. The
service will fail if
@var{device} does not exist.
@end deffn
address@hidden
address@hidden session limits
address@hidden ulimit
address@hidden priority
address@hidden {Scheme Procedure} pam-limits-service [#:limits @var{limits}]
+
+Return a service that installs a configuration file for the
address@hidden://linux-pam.org/Linux-PAM-html/sag-pam_limits.html,
address@hidden module}. The procedure optionally takes a list of
address@hidden values, which can be used to specify
address@hidden limits and nice priority limits to user sessions.
+
+The following limits definition sets two hard and soft limits for all
+login sessions of users in the @code{realtime} group:
+
address@hidden
+(pam-limits-service
+ (list
+ (pam-limits-entry "@@realtime" 'both 'rtprio 99)
+ (pam-limits-entry "@@realtime" 'both 'memlock 'unlimited)))
address@hidden example
+
+The first entry increases the maximum realtime priority for
+non-privileged processes; the second entry lifts any restriction of the
+maximum address space that can be locked in memory. These settings are
+commonly used for real-time audio systems.
address@hidden deffn
+
+
@node Scheduled Job Execution
@subsubsection Scheduled Job Execution
diff --git a/gnu/services/base.scm b/gnu/services/base.scm
index c9c2594..805ba7d 100644
--- a/gnu/services/base.scm
+++ b/gnu/services/base.scm
@@ -5,6 +5,7 @@
;;; Copyright © 2015 Sou Bunnbu <address@hidden>
;;; Copyright © 2016 Leo Famulari <address@hidden>
;;; Copyright © 2016 David Craven <address@hidden>
+;;; Copyright © 2016 Ricardo Wurmus <address@hidden>
;;;
;;; This file is part of GNU Guix.
;;;
@@ -100,6 +101,8 @@
urandom-seed-service
rngd-service-type
rngd-service
+ pam-limits-service-type
+ pam-limits-service
%base-services))
@@ -924,6 +927,46 @@ settings.
information on the configuration file syntax."
(service syslog-service-type config-file))
+(define pam-limits-service-type
+ (let ((security-limits
+ ;; Create /etc/security containing the provided "limits.conf" file.
+ (lambda (limits-file)
+ `(("security"
+ ,(computed-file
+ "security"
+ #~(begin
+ (mkdir #$output)
+ (stat #$limits-file)
+ (symlink #$limits-file
+ (string-append #$output "/limits.conf"))))))))
+ (pam-extension
+ (lambda (pam)
+ (let ((pam-limits (pam-entry
+ (control "required")
+ (module "pam_limits.so")
+ (arguments
'("conf=/etc/security/limits.conf")))))
+ (if (member (pam-service-name pam)
+ '("login" "su" "slim"))
+ (pam-service
+ (inherit pam)
+ (session (cons pam-limits
+ (pam-service-session pam))))
+ pam)))))
+ (service-type
+ (name 'limits)
+ (extensions
+ (list (service-extension etc-service-type security-limits)
+ (service-extension pam-root-service-type
+ (lambda _ (list pam-extension))))))))
+
+(define* (pam-limits-service #:optional (limits '()))
+ "Return a service that makes selected programs respect the list of
+pam-limits-entry specified in LIMITS via pam_limits.so."
+ (service pam-limits-service-type
+ (plain-file "limits.conf"
+ (string-join (map pam-limits-entry->string limits)
+ "\n"))))
+
;;;
;;; Guix services.
diff --git a/gnu/system/pam.scm b/gnu/system/pam.scm
index 743039d..cd7a342 100644
--- a/gnu/system/pam.scm
+++ b/gnu/system/pam.scm
@@ -23,6 +23,7 @@
#:use-module (gnu services)
#:use-module (ice-9 match)
#:use-module (srfi srfi-1)
+ #:use-module (srfi srfi-9)
#:use-module (srfi srfi-11)
#:use-module (srfi srfi-26)
#:use-module ((guix utils) #:select (%current-system))
@@ -38,6 +39,13 @@
pam-entry-module
pam-entry-arguments
+ pam-limits-entry
+ pam-limits-entry-domain
+ pam-limits-entry-type
+ pam-limits-entry-item
+ pam-limits-entry-value
+ pam-limits-entry->string
+
pam-services->directory
unix-pam-service
base-pam-services
@@ -76,6 +84,59 @@
(arguments pam-entry-arguments ; list of string-valued g-expressions
(default '())))
+;; PAM limits entries are used by the pam_limits PAM module to set or override
+;; limits on system resources for user sessions. The format is specified
+;; here: http://linux-pam.org/Linux-PAM-html/sag-pam_limits.html
+(define-record-type <pam-limits-entry>
+ (make-pam-limits-entry domain type item value)
+ pam-limits-entry?
+ (domain pam-limits-entry-domain) ; string
+ (type pam-limits-entry-type) ; symbol
+ (item pam-limits-entry-item) ; symbol
+ (value pam-limits-entry-value)) ; symbol or number
+
+(define (pam-limits-entry domain type item value)
+ "Construct a pam-limits-entry ensuring that the provided values are valid."
+ (define (valid? value)
+ (case item
+ ((priority) (number? value))
+ ((nice) (and (number? value)
+ (>= value -20)
+ (<= value 19)))
+ (else (or (and (number? value)
+ (>= value -1))
+ (member value '(unlimited infinity))))))
+ (define items
+ (list 'core 'data 'fsize
+ 'memlock 'nofile 'rss
+ 'stack 'cpu 'nproc
+ 'as 'maxlogins 'maxsyslogins
+ 'priority 'locks 'sigpending
+ 'msgqueue 'nice 'rtprio))
+ (when (not (member type '(hard soft both)))
+ (error "invalid limit type" type))
+ (when (not (member item items))
+ (error "invalid limit item" item))
+ (when (not (valid? value))
+ (error "invalid limit value" value))
+ (make-pam-limits-entry domain type item value))
+
+(define (pam-limits-entry->string entry)
+ "Convert a pam-limits-entry record to a string."
+ (match entry
+ (($ <pam-limits-entry> domain type item value)
+ (string-join (list domain
+ (if (eq? type 'both)
+ "-"
+ (symbol->string type))
+ (symbol->string item)
+ (cond
+ ((symbol? value)
+ (symbol->string value))
+ (else
+ (number->string value))))
+ " "))))
+
(define (pam-service->configuration service)
"Return the derivation building the configuration file for SERVICE, to be
dumped in /etc/pam.d/NAME, where NAME is the name of SERVICE."