安藤です

ご報告ありがとうございます。
coilのUUID周りでバッファオーバーフローが起こっているみたいですね。
ちょっと調べてみます。

2011年12月29日14:02 Kei Okada :
> 岡田です．
>
> OpenRTM-1.0.0を11.10でコンパイルし環境構築を試して，以下のサンプルプログラムを実行しようとしているのですが，
> http://code.google.com/p/hrpsys-base/source/browse/#svn%2Ftrunk%2Fsample%2FHRP-4C
>
> openhrp-controller-bridge を立ち上げると，
>
> Starting program:
> /home/k-okada/ros/electric/rtm-ros-robotics/rtmros_common/openhrp3/bin/openhrp-controller-bridge
> --server-name HRP-4C --periodic-rate HRP-4C\(Robot\)0:1.0
> --periodic-rate HGcontroller0:1.0 --in-port qRef:JOINT_VALUE --in-port
> dqRef:JOINT_VELOCITY --in-port ddqRef:JOINT_ACCELERATION --out-port
> q:JOINT_VALUE --out-port pr:WAIST:ABS_TRANSFORM --out-port
> image:0:COLOR_IMAGE:0.1 --connection qRef:HGcontroller0:qOut
> --connection dqRef:HGcontroller0:dqOut --connection
> ddqRef:HGcontroller0:ddqOut
> [Thread debugging using libthread_db enabled]
> [New Thread 0x7ffff307b700 (LWP 25975)]
> [New Thread 0x7ffff287a700 (LWP 25976)]
> [New Thread 0x7ffff2079700 (LWP 25977)]
> HGcontroller0: onInitialize()
> [New Thread 0x7ffff141c700 (LWP 25984)]
> [Thread 0x7ffff141c700 (LWP 25984) exited]
> [New Thread 0x7ffff0c1b700 (LWP 25985)]
> [Thread 0x7ffff0c1b700 (LWP 25985) exited]
> ready
> [New Thread 0x7ffff041a700 (LWP 25987)]
> setting naming
> periodic-rate (HGcontroller0) = 1
> detected the ExtTrigExecutionContext
> periodic-rate (HRP-4C(Robot)0) = 1
> detected the ExtTrigExecutionContext
> setup RT components
> *** buffer overflow detected ***:
> /home/k-okada/ros/electric/rtm-ros-robotics/rtmros_common/openhrp3/bin/openhrp-controller-bridge
> terminated
> ======= Backtrace: =========
> /lib/x86_64-linux-gnu/libc.so.6(__fortify_fail+0x37)[0x7ffff58b77f7]
> /lib/x86_64-linux-gnu/libc.so.6(+0xf7710)[0x7ffff58b6710]
> /home/k-okada/ros/electric/rtm-ros-robotics/rtmros_common/openrtm/lib/libcoil.so.0(_ZN4coil14UUID_Generator12generateUUIDEii+0x39)[0x7ffff6a15519]
> /home/k-okada/ros/electric/rtm-ros-robotics/rtmros_common/openrtm/lib/libRTC-1.0.0.so.0(_ZNK3RTC8PortBase7getUUIDEv+0x31)[0x7ffff6dd2c71]
> /home/k-okada/ros/electric/rtm-ros-robotics/rtmros_common/openrtm/lib/libRTC-1.0.0.so.0(_ZNK3RTC8PortBase7setUUIDERNS_16ConnectorProfileE+0x14)[0x7ffff6dd2cd4]
> /home/k-okada/ros/electric/rtm-ros-robotics/rtmros_common/openrtm/lib/libRTC-1.0.0.so.0(_ZN3RTC8PortBase7connectERNS_16ConnectorProfileE+0x125)[0x7ffff6dd4835]
> /home/k-okada/ros/electric/rtm-ros-robotics/rtmros_common/openrtm/lib/libRTC-1.0.0.so.0(_ZN3RTC10InPortBase7connectERNS_16ConnectorProfileE+0xcb)[0x7ffff6dbeefb]
> /home/k-okada/ros/electric/rtm-ros-robotics/rtmros_common/openrtm/lib/libRTC-1.0.0.so.0(+0x1f9607)[0x7ffff6e13607]
> /usr/lib/libomniORB4.so.1(_ZN4omni10omniOrbPOA8dispatchER18omniCallDescriptorP17omniLocalIdentity+0x16e)[0x7ffff78fdaee]
> /usr/lib/libomniORB4.so.1(_ZN17omniLocalIdentity8dispatchER18omniCallDescriptor+0x1a7)[0x7ffff78e31f7]
> /usr/lib/libomniORB4.so.1(_ZN10omniObjRef7_invokeER18omniCallDescriptorb+0xe7)[0x7ffff78f1b47]
> /home/k-okada/ros/electric/rtm-ros-robotics/rtmros_common/openrtm/lib/libRTC-1.0.0.so.0(_ZN3RTC19_objref_PortService7connectERNS_16ConnectorProfileE+0xc0)[0x7ffff6e2a950]
> /home/k-okada/ros/electric/rtm-ros-robotics/rtmros_common/openhrp3/bin/openhrp-controller-bridge(_ZN15Controller_impl12connectPortsEPN3RTC19_objref_PortServiceES2_+0x323)[0x4c990f]
> /home/k-okada/ros/electric/rtm-ros-robotics/rtmros_common/openhrp3/bin/openhrp-controller-bridge(_ZN15Controller_impl19setupRtcConnectionsEv+0x402)[0x4c94b8]
> /home/k-okada/ros/electric/rtm-ros-robotics/rtmros_common/openhrp3/bin/openhrp-controller-bridge(_ZN15Controller_impl10initializeEv+0xbe)[0x4ca5d0]
> /home/k-okada/ros/electric/rtm-ros-robotics/rtmros_common/openhrp3/bin/openhrp-controller-bridge[0x4e5648]
> /usr/lib/libomniORB4.so.1(_ZN14omniCallHandle6upcallEP11omniServantR18omniCallDescriptor+0x551)[0x7ffff790c0c1]
> /home/k-okada/ros/electric/rtm-ros-robotics/rtmros_common/openhrp3/bin/openhrp-controller-bridge(_ZN7OpenHRP16_impl_Controller9_dispatchER14omniCallHandle+0x2d0)[0x4e6336]
> /usr/lib/libomniORB4.so.1(_ZN4omni10omniOrbPOA8dispatchER14omniCallHandleP17omniLocalIdentity+0x18d)[0x7ffff78fe03d]
> /usr/lib/libomniORB4.so.1(_ZN17omniLocalIdentity8dispatchER14omniCallHandle+0x48)[0x7ffff78e2f38]
> /usr/lib/libomniORB4.so.1(_ZN4omni6GIOP_S13handleRequestEv+0x132)[0x7ffff7926722]
> /usr/lib/libomniORB4.so.1(_ZN4omni6GIOP_S10dispatcherEv+0x1c0)[0x7ffff7927550]
> /usr/lib/libomniORB4.so.1(_ZN4omni10giopWorker12real_executeEv+0x50)[0x7ffff7923fb0]
> /usr/lib/libomniORB4.so.1(_ZN4omni10giopWorker7executeEv+0x2f)[0x7ffff79245bf]
> /usr/lib/libomniORB4.so.1(_ZN19omniAsyncWorkerInfo3runEv+0x115)[0x7ffff78d6115]
> /usr/lib/libomniORB4.so.1(_ZN15omniAsyncWorker3runEPv+0x2f)[0x7ffff78d683f]
> /usr/lib/libomnithread.so.3(omni_thread_wrapper+0x73)[0x7ffff76114d3]
> /lib/x86_64-linux-gnu/libpthread.so.0(+0x7efc)[0x7ffff7bc6efc]
> /lib/x86_64-linux-gnu/libc.so.6(clone+0x6d)[0x7ffff58a089d]
> ======= Memory map: ========
> 00400000-00542000 r-xp 00000000 08:05 16004512
> /home/k-okada/ros/electric/rtm-ros-robotics/rtmros_common/openhrp3/bin/openhrp-controller-bridge
> 00741000-0074e000 r--p 00141000 08:05 16004512
> /home/k-okada/ros/electric/rtm-ros-robotics/rtmros_common/openhrp3/bin/openhrp-controller-bridge
> 0074e000-00750000 rw-p 0014e000 08:05 16004512
> /home/k-okada/ros/electric/rtm-ros-robotics/rtmros_common/openhrp3/bin/openhrp-controller-bridge
> 00750000-007d4000 rw-p 00000000 00:00 0 [heap]
> 7fffefc1a000-7fffefc1b000 ---p 00000000 00:00 0
> 7fffefc1b000-7ffff041b000 rw-p 00000000 00:00 0
> 7ffff041b000-7ffff041c000 ---p 00000000 00:00 0
> 7ffff041c000-7ffff0c1c000 rw-p 00000000 00:00 0
> 7ffff0c1c000-7ffff0c1d000 ---p 00000000 00:00 0
> 7ffff0c1d000-7ffff141d000 rw-p 00000000 00:00 0
> 7ffff141d000-7ffff143e000 r-xp 00000000 08:05 11018383
> /home/k-okada/ros/electric/rtm-ros-robotics/rtmros_common/hrpsys/lib/HGcontroller.so
> 7ffff143e000-7ffff163e000 ---p 00021000 08:05 11018383
> /home/k-okada/ros/electric/rtm-ros-robotics/rtmros_common/hrpsys/lib/HGcontroller.so
> 7ffff163e000-7ffff1648000 r--p 00021000 08:05 11018383
> /home/k-okada/ros/electric/rtm-ros-robotics/rtmros_common/hrpsys/lib/HGcontroller.so
> 7ffff1648000-7ffff1649000 rw-p 0002b000 08:05 11018383
> /home/k-okada/ros/electric/rtm-ros-robotics/rtmros_common/hrpsys/lib/HGcontroller.so
> 7ffff1649000-7ffff1655000 r-xp 00000000 08:05 9572154
> /lib/x86_64-linux-gnu/libnss_files-2.13.so
> 7ffff1655000-7ffff1854000 ---p 0000c000 08:05 9572154
> /lib/x86_64-linux-gnu/libnss_files-2.13.so
> 7ffff1854000-7ffff1855000 r--p 0000b000 08:05 9572154
> /lib/x86_64-linux-gnu/libnss_files-2.13.so
> 7ffff1855000-7ffff1856000 rw-p 0000c000 08:05 9572154
> /lib/x86_64-linux-gnu/libnss_files-2.13.so
> 7ffff1878000-7ffff1879000 rw-p 00000000 00:00 0
> 7ffff1879000-7ffff187a000 ---p 00000000 00:00 0
> 7ffff187a000-7ffff207a000 rw-p 00000000 00:00 0
> 7ffff207a000-7ffff207b000 ---p 00000000 00:00 0
> 7ffff207b000-7ffff287b000 rw-p 00000000 00:00 0
> 7ffff287b000-7ffff287c000 ---p 00000000 00:00 0
> 7ffff287c000-7ffff307c000 rw-p 00000000 00:00 0
> 7ffff307c000-7ffff3083000 r--s 00000000 08:05 14293888
> /usr/lib/x86_64-linux-gnu/gconv/gconv-modules.cache
> 7ffff3083000-7ffff39ec000 r--p 00000000 08:05 13900794
> /usr/lib/locale/locale-archive
> 7ffff39ec000-7ffff482c000 r--p 00000000 08:05 13897729
> /usr/lib/libicudata.so.44.2
> 7ffff482c000-7ffff4a2b000 ---p 00e40000 08:05 13897729
> /usr/lib/libicudata.so.44.2
> 7ffff4a2b000-7ffff4a2c000 rw-p 00e3f000 08:05 13897729
> /usr/lib/libicudata.so.44.2
> 7ffff4a2c000-7ffff4bdd000 r-xp 00000000 08:05 13897731
> /usr/lib/libicui18n.so.44.2
> 7ffff4bdd000-7ffff4ddd000 ---p 001b1000 08:05 13897731
> /usr/lib/libicui18n.so.44.2
> 7ffff4ddd000-7ffff4de8000 r--p 001b1000 08:05 13897731
> /usr/lib/libicui18n.so.44.2
> 7ffff4de8000-7ffff4de9000 rw-p 001bc000 08:05 13897731
> /usr/lib/libicui18n.so.44.2
> 7ffff4de9000-7ffff4dea000 rw-p 00000000 00:00 0
> 7ffff4dea000-7ffff4f1e000 r-xp 00000000 08:05 13897743
> /usr/lib/libicuuc.so.44.2
> 7ffff4f1e000-7ffff511e000 ---p 00134000 08:05 13897743
> /usr/lib/libicuuc.so.44.2
> 7ffff511e000-7ffff512d000 r--p 00134000 08:05 13897743
> /usr/lib/libicuuc.so.44.2
> 7ffff512d000-7ffff512e000 rw-p 00143000 08:05 13897743
> /usr/lib/libicuuc.so.44.2
> 7ffff512e000-7ffff5132000 rw-p 00000000 00:00 0
> 7ffff5132000-7ffff51b5000 r-xp 00000000 08:05 9572161
> /lib/x86_64-linux-gnu/libm-2.13.so
> 7ffff51b5000-7ffff53b4000 ---p 00083000 08:05 9572161
> /lib/x86_64-linux-gnu/libm-2.13.so
> 7ffff53b4000-7ffff53b5000 r--p 00082000 08:05 9572161
> /lib/x86_64-linux-gnu/libm-2.13.so
> 7ffff53b5000-7ffff53b6000 rw-p 00083000 08:05 9572161
> /lib/x86_64-linux-gnu/libm-2.13.so
> 7ffff53b6000-7ffff53b8000 r-xp 00000000 08:05 9572152
> /lib/x86_64-linux-gnu/libdl-2.13.so
> 7ffff53b8000-7ffff55b8000 ---p 00002000 08:05 9572152
> /lib/x86_64-linux-gnu/libdl-2.13.so
> 7ffff55b8000-7ffff55b9000 r--p 00002000 08:05 9572152
> /lib/x86_64-linux-gnu/libdl-2.13.so
> 7ffff55b9000-7ffff55ba000 rw-p 00003000 08:05 9572152
> /lib/x86_64-linux-gnu/libdl-2.13.so
> 7ffff55ba000-7ffff55be000 r-xp 00000000 08:05 9571960
> /lib/x86_64-linux-gnu/libuuid.so.1.3.0
> 7ffff55be000-7ffff57bd000 ---p 00004000 08:05 9571960
> /lib/x86_64-linux-gnu/libuuid.so.1.3.0
> 7ffff57bd000-7ffff57be000 r--p 00003000 08:05 9571960
> /lib/x86_64-linux-gnu/libuuid.so.1.3.0
> 7ffff57be000-7ffff57bf000 rw-p 00004000 08:05 9571960
> /lib/x86_64-linux-gnu/libuuid.so.1.3.0
> 7ffff57bf000-7ffff5954000 r-xp 00000000 08:05 9572151
> /lib/x86_64-linux-gnu/libc-2.13.so
> 7ffff5954000-7ffff5b53000 ---p 00195000 08:05 9572151
> /lib/x86_64-linux-gnu/libc-2.13.so
> 7ffff5b53000-7ffff5b57000 r--p 00194000 08:05 9572151
> /lib/x86_64-linux-gnu/libc-2.13.so
> 7ffff5b57000-7ffff5b58000 rw-p 00198000 08:05 9572151
> /lib/x86_64-linux-gnu/libc-2.13.so
> 7ffff5b58000-7ffff5b5e000 rw-p 00000000 00:00 0
> 7ffff5b5e000-7ffff5b73000 r-xp 00000000 08:05 9571904
> /lib/x86_64-linux-gnu/libgcc_s.so.1
> 7ffff5b73000-7ffff5d72000 ---p 00015000 08:05 9571904
> /lib/x86_64-linux-gnu/libgcc_s.so.1
> 7ffff5d72000-7ffff5d73000 r--p 00014000 08:05 9571904
> /lib/x86_64-linux-gnu/libgcc_s.so.1
> 7ffff5d73000-7ffff5d74000 rw-p 00015000 08:05 9571904
> /lib/x86_64-linux-gnu/libgcc_s.so.1
> 7ffff5d74000-7ffff5e5c000 r-xp 00000000 08:05 13894116
> /usr/lib/x86_64-linux-gnu/libstdc++.so.6.0.16
> 7ffff5e5c000-7ffff605c000 ---p 000e8000 08:05 13894116
> /usr/lib/x86_64-linux-gnu/libstdc++.so.6.0.16
> 7ffff605c000-7ffff6064000 r--p 000e8000 08:05 13894116
> /usr/lib/x86_64-linux-gnu/libstdc++.so.6.0.16
> 7ffff6064000-7ffff6066000 rw-p 000f0000 08:05 13894116
> /usr/lib/x86_64-linux-gnu/libstdc++.so.6.0.16
> 7ffff6066000-7ffff607b000 rw-p 00000000 00:00 0
> 7ffff607b000-7ffff607e000 r-xp 00000000 08:05 13903971
> /usr/lib/libboost_system.so.1.46.1
> 7ffff607e000-7ffff627d000 ---p 00003000 08:05 13903971
> /usr/lib/libboost_system.so.1.46.1
> 7ffff627d000-7ffff627e000 r--p 00002000 08:05 13903971
> /usr/lib/libboost_system.so.1.46.1
> 7ffff627e000-7ffff627f000 rw-p 00003000 08:05 13903971
> /usr/lib/libboost_system.so.1.46.1
> 7ffff627f000-7ffff637a000 r-xp 00000000 08:05 13904106
> /usr/lib/libboost_regex.so.1.46.1connect HRP-4C(Robot)0:qRef <-->
> HGcontroller0:qOut
> Program received signal SIGABRT, Aborted.
> [Switching to Thread 0x7ffff041a700 (LWP 25987)]
> 0x00007ffff57f53a5 in __GI_raise (sig=6)
> at ../nptl/sysdeps/unix/sysv/linux/raise.c:64
> 64 ../nptl/sysdeps/unix/sysv/linux/raise.c: そのようなファイルやディレクトリはありません.
> in ../nptl/sysdeps/unix/sysv/linux/raise.c
>
>
> (gdb) where
> #0 0x00007ffff57f53a5 in __GI_raise (sig=6)
> at ../nptl/sysdeps/unix/sysv/linux/raise.c:64
> #1 0x00007ffff57f8b0b in __GI_abort () at abort.c:92
> #2 0x00007ffff582d113 in __libc_message (do_abort=2,
> fmt=0x7ffff591c61e "*** %s ***: %s terminated\n")
> at ../sysdeps/unix/sysv/linux/libc_fatal.c:189
> #3 0x00007ffff58b77f7 in __GI___fortify_fail (
> msg=0x7ffff591c5b5 "buffer overflow detected") at fortify_fail.c:32
> #4 0x00007ffff58b6710 in __GI___chk_fail () at chk_fail.c:29
> #5 0x00007ffff6a15519 in coil::UUID_Generator::generateUUID(int, int) ()
> from /home/k-okada/ros/electric/rtm-ros-robotics/rtmros_common/openrtm/lib/libcoil.so.0
> #6 0x00007ffff6dd2c71 in RTC::PortBase::getUUID() const ()
> from /home/k-okada/ros/electric/rtm-ros-robotics/rtmros_common/openrtm/lib/libRTC-1.0.0.so.0
> #7 0x00007ffff6dd2cd4 in RTC::PortBase::setUUID(RTC::ConnectorProfile&) const
> ()
> from /home/k-okada/ros/electric/rtm-ros-robotics/rtmros_common/openrtm/lib/libRTC-1.0.0.so.0
> #8 0x00007ffff6dd4835 in RTC::PortBase::connect(RTC::ConnectorProfile&) ()
> from /home/k-okada/ros/electric/rtm-ros-robotics/rtmros_common/openrtm/lib/libRTC-1.0.0.so.0
> #9 0x00007ffff6dbeefb in RTC::InPortBase::connect(RTC::ConnectorProfile&) ()
> ---Type to continue, or q to quit---
> from /home/k-okada/ros/electric/rtm-ros-robotics/rtmros_common/openrtm/lib/libRTC-1.0.0.so.0
> #10 0x00007ffff6e13607 in
> _0RL_lcfn_bf82f9885dac07a6_64000000(omniCallDescriptor*, omniServant*)
> ()
> from /home/k-okada/ros/electric/rtm-ros-robotics/rtmros_common/openrtm/lib/libRTC-1.0.0.so.0
> #11 0x00007ffff78fdaee in
> omni::omniOrbPOA::dispatch(omniCallDescriptor&, omniLocalIdentity*) ()
> from /usr/lib/libomniORB4.so.1
> #12 0x00007ffff78e31f7 in omniLocalIdentity::dispatch(omniCallDescriptor&) ()
> from /usr/lib/libomniORB4.so.1
> #13 0x00007ffff78f1b47 in omniObjRef::_invoke(omniCallDescriptor&, bool) ()
> from /usr/lib/libomniORB4.so.1
> #14 0x00007ffff6e2a950 in
> RTC::_objref_PortService::connect(RTC::ConnectorProfile&) ()
> from /home/k-okada/ros/electric/rtm-ros-robotics/rtmros_common/openrtm/lib/libRTC-1.0.0.so.0
> #15 0x00000000004c990f in Controller_impl::connectPorts (this=0x7b37f0,
> outPort=0x7a69a0, inPort=0x7c22e0)
> at /home/k-okada/ros/electric/rtm-ros-robotics/rtmros_common/openhrp3/build/openhrp-aist-grx-svn/server/ControllerBridge/Controller_impl.cpp:322
> #16 0x00000000004c94b8 in Controller_impl::setupRtcConnections (this=0x7b37f0)
> at /home/k-okada/ros/electric/rtm-ros-robotics/rtmros_common/openhrp3/build/openhrp-aist-grx-svn/server/ControllerBridge/Controller_impl.cpp:264
> ---Type to continue, or q to quit---
> #17 0x00000000004ca5d0 in Controller_impl::initialize (this=0x7b37f0)
> at /home/k-okada/ros/electric/rtm-ros-robotics/rtmros_common/openhrp3/build/openhrp-aist-grx-svn/server/ControllerBridge/Controller_impl.cpp:526
> #18 0x00000000004e5648 in _0RL_lcfn_337053878413040c_90000000 (
> cd=0x7ffff04199e0, svnt=0x7b38e0)
> at /home/k-okada/ros/electric/rtm-ros-robotics/rtmros_common/openhrp3/build/openhrp-aist-grx-svn/hrplib/hrpCorba/ControllerSk.cpp:475
> #19 0x00007ffff790c0c1 in omniCallHandle::upcall(omniServant*,
> omniCallDescriptor&) () from /usr/lib/libomniORB4.so.1
> #20 0x00000000004e6336 in OpenHRP::_impl_Controller::_dispatch (this=0x7b37f0,
> _handle=...)
> at /home/k-okada/ros/electric/rtm-ros-robotics/rtmros_common/openhrp3/build/openhrp-aist-grx-svn/hrplib/hrpCorba/ControllerSk.cpp:736
> #21 0x00007ffff78fe03d in omni::omniOrbPOA::dispatch(omniCallHandle&,
> omniLocalIdentity*) () from /usr/lib/libomniORB4.so.1
> #22 0x00007ffff78e2f38 in omniLocalIdentity::dispatch(omniCallHandle&) ()
> from /usr/lib/libomniORB4.so.1
> #23 0x00007ffff7926722 in omni::GIOP_S::handleRequest() ()
> from /usr/lib/libomniORB4.so.1
> #24 0x00007ffff7927550 in omni::GIOP_S::dispatcher() ()
> from /usr/lib/libomniORB4.so.1
> #25 0x00007ffff7923fb0 in omni::giopWorker::real_execute() ()
> from /usr/lib/libomniORB4.so.1
> ---Type to continue, or q to quit---
> #26 0x00007ffff79245bf in omni::giopWorker::execute() ()
> from /usr/lib/libomniORB4.so.1
> #27 0x00007ffff78d6115 in omniAsyncWorkerInfo::run() ()
> from /usr/lib/libomniORB4.so.1
> #28 0x00007ffff78d683f in omniAsyncWorker::run(void*) ()
> from /usr/lib/libomniORB4.so.1
> #29 0x00007ffff76114d3 in omni_thread_wrapper ()
> from /usr/lib/libomnithread.so.3
> #30 0x00007ffff7bc6efc in start_thread (arg=0x7ffff041a700)
> at pthread_create.c:304
> #31 0x00007ffff58a089d in clone ()
> at ../sysdeps/unix/sysv/linux/x86_64/clone.S:112
> #32 0x0000000000000000 in ?? ()
>
> というエラーになりました．ただし，OpenRTMをコンパイルするときに./configure --enable-debug をつけると
> うまく動いていると言う状況です．
>
> とりあえずの現状報告と情報共有ということでよろしくお願いいたします．
> _______________________________________________
> openrtm-users mailing list
> openrtm-users@openrtm.org
> http://www.openrtm.org/mailman/listinfo/openrtm-users