[OpenWrt-Devel] python ctypes.util.find_library cannot find libc

Alexandru Ardelean ardeleanalex at gmail.com
Thu Jan 19 04:31:26 EST 2017


Hey,

So, I've tried to run  an OpenWrt system, x86_64,
https://github.com/openwrt/openwrt/commit/4e53a6e9c560b54361f9ed3639e8d12f9ab8939d

It was hanging on boot.
I've ran in Virtual Machine Manager with QEMU/KVM.
HDD emulation is SATA/AHCI [ I checked it's SATA/AHCI ]

It looks to me that it's hanging at  trying to mount root device  /dev/mtdblock0
Any thoughts ?

[    1.213897] ata4: SATA link down (SStatus 0 SControl 300)
[    1.214781] ata2: SATA link down (SStatus 0 SControl 300)
[    1.215572] ata6: SATA link down (SStatus 0 SControl 300)
[    1.216359] ata1: SATA link up 1.5 Gbps (SStatus 113 SControl 300)
[    1.217229] ata1.00: ATA-7: QEMU HARDDISK, 2.3.1, max UDMA/100
[    1.217976] ata1.00: 31233 sectors, multi 16: LBA48 NCQ (depth 31/32)
[    1.218787] ata1.00: applying bridge limits
[    1.233284] ata1.00: configured for UDMA/100
[    1.234233] ata5: SATA link down (SStatus 0 SControl 300)
[    1.235915] ata3: SATA link down (SStatus 0 SControl 300)
[    1.237371] scsi 0:0:0:0: Direct-Access     ATA      QEMU HARDDISK
  1    PQ: 0 ANSI: 5
[    1.239155] sd 0:0:0:0: [sda] 31233 512-byte logical blocks: (16.0
MB/15.3 MiB)
[    1.241487] sd 0:0:0:0: [sda] Write Protect is off
[    1.242882] sd 0:0:0:0: [sda] Write cache: enabled, read cache:
enabled, doesn't support DPO or FUA
[    1.245329]  sda: sda1 sda2
[    1.245887] sda: p2 size 262144 extends beyond EOD, enabling native capacity
[    1.247232]  sda: sda1 sda2
[    1.247784] sda: p2 size 262144 extends beyond EOD, truncated
[    1.248864] sd 0:0:0:0: [sda] Attached SCSI disk
[    1.256721] block2mtd: erasesize must be a divisor of device size
[    1.259958] rtc_cmos 00:00: setting system clock to 2017-01-19
09:27:33 UTC (1484818053)
[    1.261388] Waiting for root device /dev/mtdblock0...

On Wed, Jan 18, 2017 at 6:05 PM, Alexandru Ardelean
<ardeleanalex at gmail.com> wrote:
> Hey,
>
> So, if you try on the system.
>
> echo /usr/sbin/modprobe > /proc/sys/kernel/modprobe
>
> Does it work ? I mean to just  import iptc ?
> It worked for me, but I tried on a LEDE system (x86_64), which I'm
> hoping may be similar to OpenWrt.
>
> For me, the part that interests me the most, is if this is a bug
> within Python [ since I maintain it ], and it runs on both LEDE &
> OpenWrt.
>
> Will try to spin up a OpenWrt [just cloned trunk from Github ].
>
> And I'll try to reproduce.
> For reference ; Python is version 2.7.13
> It's from here: https://github.com/openwrt/packages
>
> I could not find hash 5ba298c   in OpenWrt [
> https://github.com/openwrt/openwrt ]  nor in packages [ link above ].
>
> Will come back with findings for OpenWrt.
>
> In the meantime, I will see about proposing a solution for updating
> /proc/sys/kernel/modprobe   correctly for both LEDE & OpenWrt.
>
> Thanks
> Alex
>
>
>
> On Wed, Jan 18, 2017 at 4:38 PM, Andrew McConachie <andrew at depht.com> wrote:
>> Hi 郭涛 and Alexandru,
>>
>> ldconfig depends on using eglibc to fulfill libc requirement.
>>
>> Symbol: PACKAGE_ldconfig [=n]
>> Type  : tristate
>> Prompt: ldconfig............................... Shared library path
>> configuration
>> Location:
>> (3) -> Utilities
>> Defined at tmp/.config-package.in:82365
>> Depends on: !USE_MUSL [=y]
>>
>> If we make python depend on ldconfig, then are we saying python cannot be
>> used with MUSL libc? I don't know what the default libc is for OpenWRT or
>> whether one is considered experimental more than the other. But this is
>> something to consider.
>>
>> Thanks,
>> Andrew
>>
>>
>> On 1/18/17 03:32, 郭涛 wrote:
>>>
>>> Hi Andrew & Alexandru
>>>
>>> Forget the patch in prev mail, use attached patch instead.
>>>
>>> To use ctypes.util.find_library, you need one of gcc, ldconfig or
>>> objdump. I suggest you use ldconfig
>>>
>>> After install ldconfig,  run ldconfig first to update cache
>>> then run ldconfig -p to show all of your libraries
>>> in my case, it shows:
>>>
>>> 195 libs found in cache `/etc/ld.so.cache' (version 1.7.0)
>>>          uhttpd_tls.so (libc0) => /usr/lib/uhttpd_tls.so
>>>          rclibrary.so (libc0) => /usr/lib/rclibrary.so
>>>          libz.so.1 (libc0) => /usr/lib/libz.so.1
>>>          libz.so (libc0) => /usr/lib/libz.so
>>>          libyaml-0.so.2 (libc0) => /usr/lib/libyaml-0.so.2
>>>          ......
>>>
>>> All libraries are libc0, that's why ctypes.util.find_library does not
>>> work on my platform
>>>
>>> You need to run 'uname -m' to get your matchine name and run 'ldconfig
>>> -p' to get library type.
>>> Atter all, append  '$machine' : '$type'  to  mach_map list in
>>> ctypes/util.py and try find_library('pthread')
>>>
>>>
>>>>>> from ctypes.util import find_library
>>>>>>
>>>>>> find_library('pthread')
>>>
>>> 'libpthread.so.0'
>>>
>>>
>>>
>>>
>>>
>>>
>>> 2017-01-17 22:22 GMT+08:00 Alexandru Ardelean <ardeleanalex at gmail.com>:
>>>>
>>>> Will give it a try.
>>>>
>>>> On Mon, Jan 16, 2017 at 9:41 PM, Andrew McConachie <andrew at depht.com>
>>>> wrote:
>>>>>
>>>>> Hi Alexandru and 郭涛,
>>>>>
>>>>> Attached is the Makefile I made for python-iptables. I can work around
>>>>> this
>>>>> by hardwiring library locations in the source of python-iptables, but
>>>>> I'd
>>>>> rather do it the correct way. To reproduce this build an OpenWrt system
>>>>> with
>>>>> this Makefile and then just create a simple Python script with 'import
>>>>> iptc'.
>>>>>
>>>>> I am cloning OpenWrt from Github and running make menuconfig;make to
>>>>> build
>>>>> everything. My Github version is about 6 days old with the last commit
>>>>> at
>>>>> 5ba298c.
>>>>>
>>>>> I also found that /proc/sys/kernel/modprobe contains /sbin/modprobe,
>>>>> while
>>>>> the modprobe binary is at /usr/sbin/modprobe. According to the Debian
>>>>> man
>>>>> page on proc(5), /proc/sys/kernel/modprobe should point to the modprobe
>>>>> binary. Googling about seems also to suggest that this file should
>>>>> contain
>>>>> the location of the modprobe binary. So I would say this is also a bug.
>>>>>
>>>>> Thanks!
>>>>> --Andrew
>>>>>
>>>>>
>>>>> On 1/16/17 07:23, Alexandru Ardelean wrote:
>>>>>>
>>>>>> Hey Andrew & 郭涛
>>>>>>
>>>>>> Sorry I did not answer sooner.
>>>>>>
>>>>>> @Andrew: do you have a Makefile for the python-iptables packages ?
>>>>>> I'd like to try to build it and see the issue. Or, are you just using
>>>>>> that .py file ?
>>>>>> Can you give a bit more input on which Python version you're using,
>>>>>> and which OpenWrt version?
>>>>>>
>>>>>> If the issue is still present in the current packages trunk, I'd like
>>>>>> to
>>>>>> fix it.
>>>>>> And if  郭涛's fix works, we can apply it to trunk.
>>>>>>
>>>>>> Thanks
>>>>>> Alex
>>>>>>
>>>>>>
>>>>>> On Mon, Jan 16, 2017 at 6:23 AM, 郭涛 <guotao945 at gmail.com> wrote:
>>>>>>>
>>>>>>> I also meet this issue.
>>>>>>> I fixed it using below change
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> https://github.com/gt945/Netgear-D7800-Openwrt-Packages/commit/fab71ca0ebf36d5f7b495b96f14d459e794b7224
>>>>>>>
>>>>>>>
>>>>>>> 2017-01-13 0:43 GMT+08:00 Andrew McConachie <andrew at depht.com>:
>>>>>>>>
>>>>>>>> Hi OpenWRT Devs,
>>>>>>>>
>>>>>>>> I'm building an OpenWRT package for python-iptables for a project I'm
>>>>>>>> working on and getting this error message when attempting to use it.
>>>>>>>>
>>>>>>>>       import iptc
>>>>>>>>     File "/usr/lib/python2.7/site-packages/iptc/__init__.py", line
>>>>>>>> 10, in
>>>>>>>> <module>
>>>>>>>>       from ip4tc import (is_table_available, Table, Chain, Rule,
>>>>>>>> Match,
>>>>>>>> Target,
>>>>>>>>     File "/usr/lib/python2.7/site-packages/iptc/ip4tc.py", line 13,
>>>>>>>> in
>>>>>>>> <module>
>>>>>>>>       from xtables import (XT_INV_PROTO, NFPROTO_IPV4, XTablesError,
>>>>>>>> xtables,
>>>>>>>>     File "/usr/lib/python2.7/site-packages/iptc/xtables.py", line
>>>>>>>> 677, in
>>>>>>>> <module>
>>>>>>>>       _optind = ct.c_long.in_dll(_libc, "optind")
>>>>>>>> AttributeError: 'NoneType' object has no attribute '_handle'
>>>>>>>>
>>>>>>>> You can view xtables.py here if you're curious.
>>>>>>>> https://github.com/ldx/python-iptables/blob/master/iptc/xtables.py
>>>>>>>>
>>>>>>>> The problem is that my python-iptables package cannot find libc
>>>>>>>> functions
>>>>>>>> using ctypes.util.find_library(). I've tried building OpenWRT using
>>>>>>>> both
>>>>>>>> musl and eglibc but neither work. I've also tried building OpenWRT
>>>>>>>> with
>>>>>>>> objdump and ldconfig. When I include ldconfig via 'make menuconfig'
>>>>>>>> it
>>>>>>>> doesn't actually populate my OpenWRT image with an ldconfig binary.
>>>>>>>> Maybe
>>>>>>>> this is the problem?
>>>>>>>>
>>>>>>>> This bug report looks similar to my problem, but it's about MIPS and
>>>>>>>> marked
>>>>>>>> as closed.
>>>>>>>> https://dev.openwrt.org/ticket/20123
>>>>>>>>
>>>>>>>> Any help or pointers would be much appreciated.
>>>>>>>>
>>>>>>>> Thanks,
>>>>>>>> Andrew
>>>>>>>> _______________________________________________
>>>>>>>> openwrt-devel mailing list
>>>>>>>> openwrt-devel at lists.openwrt.org
>>>>>>>> https://lists.openwrt.org/cgi-bin/mailman/listinfo/openwrt-devel
>>>>>>>
>>>>>>> _______________________________________________
>>>>>>> openwrt-devel mailing list
>>>>>>> openwrt-devel at lists.openwrt.org
>>>>>>> https://lists.openwrt.org/cgi-bin/mailman/listinfo/openwrt-devel
>>>>>
>>>>>
>>
_______________________________________________
openwrt-devel mailing list
openwrt-devel at lists.openwrt.org
https://lists.openwrt.org/cgi-bin/mailman/listinfo/openwrt-devel


More information about the openwrt-devel mailing list