[lxc-devel] [PATCHv2 10/12] rewrite lxc-ps
David Ward
david.ward at ll.mit.edu
Sun Mar 11 17:00:52 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.
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 | 311 +++++++++++++++++++----------------------------------
1 files changed, 109 insertions(+), 202 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..4ea68e6
--- 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 +17,123 @@
# 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;
-}
-
-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($$ref_cgroup);
- return;
-}
-
-sub get_pids_in_containers {
- my $ref_names = shift;
- my $ref_cgroup = shift;
- my $ref_pids = shift;
- my $init_cgroup = shift;
- my @pidlist;
-
- for (@{$ref_names}) {
- my $task_file = "$$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);
-}
-
-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;
+usage()
+{
+ echo "usage: $(basename $0) [--lxc | --name NAME] [--] [PS_OPTIONS...]" >&2
}
-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;
+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_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;
-}
+get_parent_cgroup()
+{
+ local hierarchies hierarchy fields subsystems init_cgroup mountpoint
-sub display_headers {
- printf "%-10s %s", "CONTAINER", $PS_HEADERS;
-}
+ parent_cgroup=""
-sub display_usage {
- print <<EOF;
-Usage: lxc-ps [--help] [--usage] [-n|--name NAME...] [--lxc] [-- ps options]
-EOF
-}
-
-sub display_help {
- display_usage;
- print <<EOF;
+ # Obtain a list of hierarchies that contain one or more subsystems
+ hierarchies=$(tail -n +2 /proc/cgroups | cut -f 2)
-Display processes information with related container name if available.
+ # 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=${fields#*:}
-Options:
---help Display this help.
---usage Display the command usage.
---name Display processes related to given containers.
- Containers are identified by a comma separated list of
- their names.
---lxc Display processes related to all lxc containers.
-
-Other available options correspond to the ps ones, see the ps manual
-or try a 'ps --help' for further details.
-EOF
-}
+ # Get a comma-separated list of the hierarchy's subsystems
+ subsystems=${fields%:*}
-use Getopt::Long qw(:config pass_through);
+ # Get the cgroup of the init process in the hierarchy
+ init_cgroup=${fields#*:}
-my $arg_help = '';
-my $arg_usage = '';
-my $arg_lxc = '';
-my @arg_name;
-my $init_cgroup = '/';
+ # Get the filesystem mountpoint of the hierarchy
+ mountpoint=$(grep -E "^cgroup [^ ]+ [^ ]+ ([^ ]+,)?$subsystems(,[^ ]+)? " /proc/self/mounts | cut -d ' ' -f 2)
+ if [ -z "$mountpoint" ]; then continue; fi
-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 $pid_list", at ARGV);
- }
+ # Return the absolute path to the containers' parent cgroup
+ parent_cgroup="${mountpoint}${init_cgroup%/}/lxc"
+ break
+ done
}
-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
+ case $line in
+ *" PID"*)
+ buffer=${line%" PID"*}
+ let line_pid_end_position=${#buffer}+4
+ printf "%-${container_field_width}s %s\n" "CONTAINER" "$line"
+ continue;;
+ *)
+ echo "$(basename $0): no PID column found in \`ps' output" >&2
+ exit 1;;
+ esac
+ fi
+
+ buffer=${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;
--
1.7.1
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