[lxc-devel] [PATCHv3 12/14] rewrite lxc-ps
David Ward
david.ward at ll.mit.edu
Wed Mar 21 23:28:53 UTC 2012
Use bash instead of perl; eliminates final lxc dependency on perl
(beneficial for minimal operating system environments).
Modify the cgroup search to only use hierarchies that contain one
or more subsystems. When searching, if a hierarchy contains the
'ns' subsystem, do not append '/lxc' to the parent cgroup.
Maintain column spacing. Expand container name column as necessary.
Properly handle spaces in 'ps' output that are not field separators
(for example, try 'lxc-ps -o pid,args').
Fix file mode in repository.
Signed-off-by: David Ward <david.ward at ll.mit.edu>
---
src/lxc/lxc-ps.in | 329 +++++++++++++++++++---------------------------------
1 files changed, 120 insertions(+), 209 deletions(-)
mode change 100755 => 100644 src/lxc/lxc-ps.in
diff --git a/src/lxc/lxc-ps.in b/src/lxc/lxc-ps.in
old mode 100755
new mode 100644
index 2fa7b8b..a9923f0
--- a/src/lxc/lxc-ps.in
+++ b/src/lxc/lxc-ps.in
@@ -1,9 +1,7 @@
-#!/usr/bin/perl
-#
-# lxc-ps
+#!/bin/bash
+
#
-# Authors:
-# Daniel Lezcano <daniel.lezcano at free.fr>
+# lxc: linux Container library
# This library is free software; you can redistribute it and/or
# modify it under the terms of the GNU Lesser General Public
@@ -19,214 +17,127 @@
# License along with this library; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
-#
-# This script allows to
-# display processes information with related container name if available.
-#
-use strict;
-
-
-# Some globals
-
-our $PS_HEADERS; # String containing headers of the ps output
-our $PS_PID_INDEX; # Index of the PID column in the ps headers
-our @PS_LINES; # Output lines of the ps command
-
-our $LXC_DISPLAY = 0; # By default do not display container information
-our %LXC_NAMES; # Specified container names (if any)
-
-sub get_container_names {
- my $ref_names = shift;
- my $lxcpath = '@LXCPATH@';
-
- open(active, "netstat -xa | grep $lxcpath |") or return;
- while(<active>) {
- chomp;
- s#.*$lxcpath/(.*)/command.*#$1#;
- push @$ref_names, $_;
- }
- close active;
+usage()
+{
+ echo "usage: $(basename $0) [--lxc | --name NAME] [--] [PS_OPTIONS...]" >&2
}
-sub get_cgroup {
- my $ref_cgroup = shift;
- my $mount_string;
-
- $mount_string=`mount -t cgroup |grep -E -e '^lxc '`;
- if ($mount_string) {
- # use the one 'lxc' cgroup mount if it exists
- chomp($mount_string);
- $$ref_cgroup=`echo "$mount_string" |cut -d' ' -f3`;
- chomp($$ref_cgroup);
- }
- # Otherwise (i.e. cgroup-bin) use the first cgroup mount
- $mount_string=`grep -m1 -E '^[^ \t]+[ \t]+[^ \t]+[ \t]+cgroup' /proc/self/mounts`;
- unless ($mount_string) {
- die "unable to find mounted cgroup" unless $$ref_cgroup;
- }
- chomp($mount_string);
- $$ref_cgroup=`echo "$mount_string" |cut -d' ' -f2`;
- chomp($$ref_cgroup);
- return;
+help() {
+ usage
+ echo >&2
+ echo "List current processes with container names." >&2
+ echo >&2
+ echo " --lxc show processes in all containers" >&2
+ echo " --name NAME show processes in the specified container" >&2
+ echo " (multiple containers can be separated by commas)" >&2
+ echo " PS_OPTIONS ps command options (see \`ps --help')" >&2
}
-sub get_pids_in_containers {
- my $ref_names = shift;
- my $ref_cgroup = shift;
- my $ref_pids = shift;
- my $init_cgroup = shift;
- my @pidlist;
-
- for (@{$ref_names}) {
- my $task_file = "$$ref_cgroup/$init_cgroup/lxc/$_/tasks";
-
- $LXC_NAMES{$_} = 1;
- open(tasks, "cat $task_file 2>/dev/null |") or next;
- while (<tasks>) {
- chomp $_;
- push @pidlist, $_;
- }
- close tasks;
- }
- $$ref_pids = join(',', @pidlist);
+get_parent_cgroup()
+{
+ local hierarchies hierarchy fields subsystems init_cgroup mountpoint
+
+ parent_cgroup=""
+
+ # Obtain a list of hierarchies that contain one or more subsystems
+ hierarchies=$(tail -n +2 /proc/cgroups | cut -f 2)
+
+ # Iterate through the list until a suitable hierarchy is found
+ for hierarchy in $hierarchies; do
+ # Obtain information about the init process in the hierarchy
+ fields=$(grep -E "^$hierarchy:" /proc/1/cgroup | head -n 1)
+ if [ -z "$fields" ]; then continue; fi
+ fields=${fields#*:}
+
+ # Get a comma-separated list of the hierarchy's subsystems
+ subsystems=${fields%:*}
+
+ # Get the cgroup of the init process in the hierarchy
+ init_cgroup=${fields#*:}
+
+ # Get the filesystem mountpoint of the hierarchy
+ mountpoint=$(grep -E "^cgroup [^ ]+ [^ ]+ ([^ ]+,)?$subsystems(,[^ ]+)? " /proc/self/mounts | cut -d ' ' -f 2)
+ if [ -z "$mountpoint" ]; then continue; fi
+
+ # Return the absolute path to the containers' parent cgroup
+ # (do not append '/lxc' if the hierarchy contains the 'ns' subsystem)
+ if [[ ",$subsystems," == *,ns,* ]]; then
+ parent_cgroup="${mountpoint}${init_cgroup%/}"
+ else
+ parent_cgroup="${mountpoint}${init_cgroup%/}/lxc"
+ fi
+ break
+ done
}
-sub reclaim_pid_index {
- my @headers = split " ", $PS_HEADERS;
- for my $i (0 .. $#headers) {
- if ($headers[$i] eq "PID") {
- $PS_PID_INDEX = $i;
- return;
- }
- }
- print "Cannot find ps PID column !\n";
- exit 1;
-}
-
-sub execute_ps {
- open(ps, "ps @_ |") or die "Cannot execute ps command: $!\n";
-
- $PS_HEADERS = <ps>;
- reclaim_pid_index;
-
- while (<ps>) {
- push @PS_LINES, $_;
- }
- close ps;
-}
-
-sub get_init_cgroup {
- my $filename = "/proc/1/cgroup";
- open(LXC, "$filename");
- my @cgroup = <LXC>;
- close LXC;
- my $container = '';
- foreach ( @cgroup ) {
- chomp;
- # find the container name after :/
- s/.*:\///o;
- }
- return $container;
-}
-
-sub get_container {
- my $pid = shift;
- my $filename = "/proc/$pid/cgroup";
- open(LXC, "$filename");
- # read all lines at once
- my @cgroup = <LXC>;
- close LXC;
- my $container = '';
- foreach ( @cgroup ) {
- chomp;
- # find the container name after :/
- s/.*:\///o;
- # chop off everything up to 'lxc/'
- s/lxc\///o;
- $container = $_;
- }
- return $container;
-}
-
-sub display_headers {
- printf "%-10s %s", "CONTAINER", $PS_HEADERS;
-}
-
-sub display_usage {
- print <<EOF;
-Usage: lxc-ps [--help] [--usage] [-n|--name NAME...] [--lxc] [-- ps options]
-EOF
-}
-
-sub display_help {
- display_usage;
- print <<EOF;
-
-Display processes information with related container name if available.
-
-Options:
---help Display this help.
---usage Display the command usage.
---name Display processes related to given containers.
- Containers are identified by a comma separated list of
- their names.
---lxc Display processes related to all lxc containers.
-
-Other available options correspond to the ps ones, see the ps manual
-or try a 'ps --help' for further details.
-EOF
-}
-
-use Getopt::Long qw(:config pass_through);
-
-my $arg_help = '';
-my $arg_usage = '';
-my $arg_lxc = '';
-my @arg_name;
-my $init_cgroup = '/';
-
-GetOptions('help' => \$arg_help,
- 'usage' => \$arg_usage,
- 'lxc' => \$arg_lxc,
- 'name=s' => \@arg_name);
-
- at arg_name = split(/,/, join(',', @arg_name));
-
-# Some help
-if ($arg_help) {display_help; exit 0;}
-if ($arg_usage) {display_usage; exit 0;}
-
-if ($ARGV[0] == '--') {
- shift @ARGV;
-}
-
-# Should we filter processes related to containers
-if ($arg_lxc) {
- $LXC_DISPLAY = 1;
- get_container_names \@arg_name;
-}
-if (@arg_name > 0) {
- my $cgroup;
- my $pid_list;
- $LXC_DISPLAY = 2;
-
- $init_cgroup = get_init_cgroup();
- get_cgroup \$cgroup;
- get_pids_in_containers(\@arg_name, \$cgroup, \$pid_list, $init_cgroup);
- if ($pid_list) {
- @ARGV = ("-p $pid_list", at ARGV);
- }
-}
-
-execute_ps @ARGV;
-
-display_headers;
-for (@PS_LINES) {
- my @a = split;
- my $container = get_container $a[$PS_PID_INDEX];
- if ($LXC_DISPLAY == 2 and not $LXC_NAMES{$container}) {next;}
- if ($LXC_DISPLAY == 1 and $container eq '') {next;}
- printf "%-10s %s", $container, $_;
-}
+containers=""
+list_container_processes=0
+for i in "$@"; do
+ case $i in
+ --help)
+ help; exit 1;;
+ --name)
+ containers=$2; list_container_processes=1; shift 2;;
+ --lxc)
+ list_container_processes=1; shift;;
+ --)
+ shift; break;;
+ *)
+ break;;
+ esac
+done
+
+if [ "$list_container_processes" -eq "1" ]; then
+ set -- -e $@
+fi
+
+get_parent_cgroup
+if [ ! -d "$parent_cgroup" ]; then
+ echo "$(basename $0): no cgroup mount point found" >&2
+ exit 1
+fi
+
+declare -a container_of_pid
+container_field_width=9
+IFS=","
+if [ -z "$containers" ]; then
+ containers=( $(find $parent_cgroup -mindepth 1 -maxdepth 1 -type d -printf "%f," 2>/dev/null) )
+else
+ containers=( $containers )
+fi
+
+declare -i pid
+IFS=$'\n'
+for container in ${containers[@]}; do
+ if [ "${#container}" -gt "$container_field_width" ]; then
+ container_field_width=${#container}
+ fi
+
+ if [ -f "$parent_cgroup/$container/tasks" ]; then
+ while read pid; do
+ container_of_pid[$pid]=$container
+ done < "$parent_cgroup/$container/tasks"
+ fi
+done
+
+declare -i line_pid_end_position
+while read line; do
+ if [ -z "$line_pid_end_position" ]; then
+ if [[ "$line" != *" PID"* ]]; then
+ echo "$(basename $0): no PID column found in \`ps' output" >&2
+ exit 1
+ fi
+
+ buffer=${line%" PID"*}
+ let line_pid_end_position=${#buffer}+4
+ printf "%-${container_field_width}s %s\n" "CONTAINER" "$line"
+ continue
+ fi
+
+ buffer=${line:0:$line_pid_end_position}
+ pid=${buffer##* }
+ if [ "$list_container_processes" -eq "0" -o ! -z "${container_of_pid[pid]}" ]; then
+ printf "%-${container_field_width}s %s\n" "${container_of_pid[pid]}" "$line"
+ fi
+done < <(ps "$@")
-exit 0;
--
1.7.4.1
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