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Comparing Linux-Clone/Clone.pm (file contents):
Revision 1.1 by root, Mon Nov 28 05:43:03 2011 UTC vs.
Revision 1.6 by root, Sat Sep 3 23:47:02 2022 UTC

1=head1 NAME 1=head1 NAME
2 2
3Linux::Clone - an interface to the linux clone(2) and unshare(2) syscalls 3Linux::Clone - an interface to the linux clone, unshare, setns, pivot_root and kcmp syscalls
4 4
5=head1 SYNOPSIS 5=head1 SYNOPSIS
6 6
7 use Linux::Clone; 7 use Linux::Clone;
8 8
9=head1 DESCRIPTION 9=head1 DESCRIPTION
10 10
11This module exposes the linux clone(2) and unshare(2) syscalls to 11This module exposes the linux clone(2), unshare(2) and some related
12Perl. 12syscalls to Perl.
13 13
14=over 4 14=over 4
15 15
16=item $retval = unshare $flags 16=item $retval = unshare $flags
17 17
… …
24 Linux::Clone::NEWNS (in unshare, implies FS) 24 Linux::Clone::NEWNS (in unshare, implies FS)
25 Linux::Clone::VM (in unshare, implies SIGHAND) 25 Linux::Clone::VM (in unshare, implies SIGHAND)
26 Linux::Clone::THREAD (in unshare, implies VM, SIGHAND) 26 Linux::Clone::THREAD (in unshare, implies VM, SIGHAND)
27 Linux::Clone::SIGHAND 27 Linux::Clone::SIGHAND
28 Linux::Clone::SYSVSEM 28 Linux::Clone::SYSVSEM
29 Linux::Clone::NEWUSER (in unshare, implies CLONE_THREAD)
30 Linux::Clone::NEWPID
29 Linux::Clone::NEWUTS 31 Linux::Clone::NEWUTS
30 Linux::Clone::NEWIPC 32 Linux::Clone::NEWIPC
31 Linux::Clone::NEWNET 33 Linux::Clone::NEWNET
34 Linux::Clone::NEWCGROUP
32 35
33Example: unshare the network namespace and prove that by calling ifconfig, 36Example: unshare the network namespace and prove that by calling ifconfig,
34showing only an unconfigured lo interface. 37showing only the unconfigured lo interface.
35 38
36 Linux::Clone::unshare Linux::Clone::NEWNET 39 Linux::Clone::unshare Linux::Clone::NEWNET
37 and "unshare: $!"; 40 and "unshare: $!";
41 Linux::Clone::configure_loopback;
38 system "ifconfig -a"; 42 system "ifconfig";
39 43
40Example: unshare the network namespace, initialise the loopback interface, 44Example: unshare the network namespace, initialise the loopback interface,
41create a veth interface pair, put one interface into the parent processes 45create a veth interface pair, put one interface into the parent processes
42namespace (use ifconfig -a from another shell), configure the other 46namespace (use ifconfig -a from another shell), configure the other
43interface with 192.168.99.2 -> 192.168.99.1 and start a shell. 47interface with 192.168.99.2 -> 192.168.99.1 and start a shell.
… …
46 50
47 # unshare our network namespace 51 # unshare our network namespace
48 Linux::Clone::unshare Linux::Clone::NEWNET 52 Linux::Clone::unshare Linux::Clone::NEWNET
49 and "unshare: $!"; 53 and "unshare: $!";
50 54
55 Linux::Clone::configure_loopback;
56
51 my $ppid = getppid; 57 my $ppid = getppid;
52 58
53 system " 59 system "
54 # configure loopback interface
55 ip link set lo up
56 ip route add 127.0.0.0/8 dev lo
57
58 # create veth pair 60 # create veth pair
59 ip link add name veth_master type veth peer name veth_slave 61 ip link add name veth_master type veth peer name veth_slave
60 62
61 # move veth_master to our parent process' namespace 63 # move veth_master to our parent process' namespace
62 ip link set veth_master netns $ppid 64 ip link set veth_master netns $ppid
… …
85 use Linux::Clone; 87 use Linux::Clone;
86 88
87 Linux::Clone::unshare Linux::Clone::NEWNS 89 Linux::Clone::unshare Linux::Clone::NEWNS
88 and die "unshare: $!"; 90 and die "unshare: $!";
89 91
90 # now bind-mount /lib over /etc and ls -l /etc - scary 92 # now bind-mount /lib over /etc and ls -l /etc - looks scary
91 system "mount -n --bind /lib /etc"; 93 system "mount -n --bind /lib /etc";
92 system "ls -l /etc"; 94 system "ls -l /etc";
93 95
94=item $retval = Linux::Clone::clone $coderef, $stacksize, $flags[, $ptid, $tls, $ctid] 96=item $retval = Linux::Clone::clone $coderef, $stacksize, $flags[, $ptid, $tls, $ctid]
95 97
… …
120 Linux::Clone::VFORK 122 Linux::Clone::VFORK
121 Linux::Clone::SETTLS (not yet implemented) 123 Linux::Clone::SETTLS (not yet implemented)
122 Linux::Clone::PARENT_SETTID (not yet implemented) 124 Linux::Clone::PARENT_SETTID (not yet implemented)
123 Linux::Clone::CHILD_SETTID (not yet implemented) 125 Linux::Clone::CHILD_SETTID (not yet implemented)
124 Linux::Clone::CHILD_CLEARTID (not yet implemented) 126 Linux::Clone::CHILD_CLEARTID (not yet implemented)
127 Linux::Clone::PIDFD (not yet implemented)
125 Linux::Clone::DETACHED 128 Linux::Clone::DETACHED
126 Linux::Clone::UNTRACED 129 Linux::Clone::UNTRACED
127 Linux::Clone::NEWUSER
128 Linux::Clone::NEWPID
129 Linux::Clone::IO 130 Linux::Clone::IO
131 Linux::Clone::CSIGNAL exit signal mask
130 132
131Note that for practical reasons you basically must not use 133Note that for practical reasons you basically must not use
132C<Linux::Clone::VM> or C<Linux::Clone::VFORK>, as perl is unlikely to cope 134C<Linux::Clone::VM> or C<Linux::Clone::VFORK>, as perl is unlikely to cope
133with that. 135with that.
134 136
… …
137Example: do a fork-like clone, sharing nothing, slightly confusing perl 139Example: do a fork-like clone, sharing nothing, slightly confusing perl
138and your libc, and exit immediately. 140and your libc, and exit immediately.
139 141
140 my $pid = Linux::Clone::clone sub { warn "in child"; 77 }, 0, POSIX::SIGCHLD; 142 my $pid = Linux::Clone::clone sub { warn "in child"; 77 }, 0, POSIX::SIGCHLD;
141 143
144=item Linux::Clone::setns $fh_or_fd[, $nstype]
145
146Calls setns(2) on the file descriptor (or file handle) C<$fh_or_fd>. If
147C<$nstype> is missing, then C<0> is used.
148
149The argument C<$nstype> can be C<0>, C<Linux::Clone::NEWIPC>,
150C<Linux::Clone::NEWNET>, C<Linux::Clone::NEWUTS>, C<Linux::Clone::NEWCGROUP>,
151C<Linux::Clone::NEWNS>, C<Linux::Clone::NEWPID> or C<Linux::Clone::NEWUSER>.
152
153=item Linux::Clone::pivot_root $new_root, $old_root
154
155Calls pivot_root(2) - refer to its manpage for details.
156
157=item Linux::Clone::kcmp $pid1, $pid2, $type[, $idx1, $idx2]
158
159Calls kcmp(2) - refer to its manpage for details on operations.
160
161The following C<$type> constants are available if the kcmp syscall number
162was available during compilation:
163
164C<Linux::Clone::KCMP_FILE>, C<Linux::Clone::KCMP_VM>, C<Linux::Clone::KCMP_FILES>,
165C<Linux::Clone::KCMP_FS>, C<Linux::Clone::KCMP_SIGHAND>, C<Linux::Clone::KCMP_IO> and
166C<Linux::Clone::KCMP_SYSVSEM>.
167
168=item Linux::Clone::configure_loopback
169
170Configures a working loopback interface (basically, does the equivalent of
171"ifconfig lo up" which automatically adds ipv4/ipv6 addresses and routes),
172which can be useful to get a network namespace going.
173
174Dies on error and returns nothing.
175
142=back 176=back
143 177
144=cut 178=cut
145 179
146package Linux::Clone; 180package Linux::Clone;
147 181
148# use common::sense; 182# use common::sense;
149 183
150BEGIN { 184BEGIN {
151 our $VERSION = '0.01'; 185 our $VERSION = '1.3';
152 186
153 require XSLoader; 187 require XSLoader;
154 XSLoader::load (__PACKAGE__, $VERSION); 188 XSLoader::load (__PACKAGE__, $VERSION);
155} 189}
156 190
191sub configure_loopback() {
192 siocsifflags "lo"
193 and die "Linux::Clone::configure_looopback: unable to bring up loopback interface: $!\n";
194}
195
1571; 1961;
158 197
159=head1 AUTHOR 198=head1 AUTHOR
160 199
161 Marc Lehmann <schmorp@schmorp.de> 200 Marc Lehmann <schmorp@schmorp.de>

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