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authorLudovic Courtès <ludo@gnu.org>2014-05-14 16:35:35 +0200
committerLudovic Courtès <ludo@gnu.org>2014-05-14 19:07:03 +0200
commit17a4d344899dca6a429fc79bc3b54edbe5079956 (patch)
treee58be784c73f1c66d5a3d5f31e41908e7f5548d7 /guix/build
parent211345b3a5097f9a6ed036c9a6a231ec9fa34ad8 (diff)
syscalls: Add 'processes' to list all the live processes.
* guix/build/syscalls.scm (kernel?, processes): New procedures.
Diffstat (limited to 'guix/build')
-rw-r--r--guix/build/syscalls.scm29
1 files changed, 28 insertions, 1 deletions
diff --git a/guix/build/syscalls.scm b/guix/build/syscalls.scm
index 90cacc760b..7a1bad7331 100644
--- a/guix/build/syscalls.scm
+++ b/guix/build/syscalls.scm
@@ -22,13 +22,15 @@
#:use-module (srfi srfi-1)
#:use-module (ice-9 rdelim)
#:use-module (ice-9 match)
+ #:use-module (ice-9 ftw)
#:export (errno
MS_RDONLY
MS_REMOUNT
MS_BIND
MS_MOVE
mount
- umount))
+ umount
+ processes))
;;; Commentary:
;;;
@@ -153,4 +155,29 @@ constants from <sys/mount.h>."
(when update-mtab?
(remove-from-mtab target))))))
+(define (kernel? pid)
+ "Return #t if PID designates a \"kernel thread\" rather than a normal
+user-land process."
+ (let ((stat (call-with-input-file (format #f "/proc/~a/stat" pid)
+ (compose string-tokenize read-string))))
+ ;; See proc.txt in Linux's documentation for the list of fields.
+ (match stat
+ ((pid tcomm state ppid pgrp sid tty_nr tty_pgrp flags min_flt
+ cmin_flt maj_flt cmaj_flt utime stime cutime cstime
+ priority nice num_thread it_real_value start_time
+ vsize rss rsslim
+ (= string->number start_code) (= string->number end_code) _ ...)
+ ;; Got this obscure trick from sysvinit's 'killall5' program.
+ (and (zero? start_code) (zero? end_code))))))
+
+(define (processes)
+ "Return the list of live processes."
+ (sort (filter-map (lambda (file)
+ (let ((pid (string->number file)))
+ (and pid
+ (not (kernel? pid))
+ pid)))
+ (scandir "/proc"))
+ <))
+
;;; syscalls.scm ends here