[dpdk-dev] building shared library

[Newman Poborsky]

Hi,

sure, here it is:
ldd libdpdk-api.so
        linux-vdso.so.1 =>  (0x00007fff3fffe000)
        libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007f583dd99000)
        /lib64/ld-linux-x86-64.so.2 (0x00007f583e5d4000)
        libpthread.so.0 => /lib/x86_64-linux-gnu/libpthread.so.0
(0x00007f583db7a000)

This is a library built with Makefile that has the following options:
RTE_BUILD_SHARED_LIB=y
CFLAGS += -fPIC
LDLIBS += -lrte_eal -lrte_mbuf -lrte_cmdline -lrte_timer  -lrte_mempool
-lrte_ring  -lrte_pmd_ring -lethdev -lrte_malloc
include $(RTE_SDK)/mk/rte.extshared.mk

There are no missing libraries.

I also had to add '-fPIC' flag to all Makefiles of lrte_*  libs above.   Is
this the correct way to build shared lib? Am I missing something?

When I build it as a regular dpdk app (like helloworld example) ldd output
is this:
ldd dpdk-api
        linux-vdso.so.1 =>  (0x00007fffacbfe000)
        libm.so.6 => /lib/x86_64-linux-gnu/libm.so.6 (0x00007ffe91b2b000)
        librt.so.1 => /lib/x86_64-linux-gnu/librt.so.1 (0x00007ffe91922000)
        libdl.so.2 => /lib/x86_64-linux-gnu/libdl.so.2 (0x00007ffe9171e000)
        libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007ffe91139000)
        /lib64/ld-linux-x86-64.so.2 (0x00007ffe92042000)
        libpcap.so.1 => /usr/local/lib/libpcap.so.1 (0x00007ffe90ef8000)

Thank you for any help!

BR,
Newman P.


On Tue, Nov 11, 2014 at 4:28 AM, Chi, Xiaobo (NSN - CN/Hangzhou) <
xiaobo.chi at nsn.com> wrote:

> Hi,
> I am using DPDK based shared lib, but never met such problems. Can you
> please share this the result of "ldd xxxxx.so" and check if all those
> depended lib are all avalible?
>
> brgs,
> chi xiaobo
>
> -----Original Message-----
> From: dev [mailto:dev-bounces at dpdk.org] On Behalf Of ext Newman Poborsky
> Sent: Monday, November 10, 2014 10:23 PM
> To: dev at dpdk.org
> Subject: [dpdk-dev] building shared library
>
> Hi,
>
> is it possible to build a  dpdk app as a shared library?
>
> I tried to put 'include $(RTE_SDK)/mk/rte.extshared.mk' in my Makefile
> (and
> define SHARED) and it builds .so lib, but all rte_* symbols are undefined.
>
> After that i tried adding:
> LDLIBS += -lrte_eal -lrte_mbuf -lrte_cmdline -lrte_timer  -lrte_mempool
> -lrte_ring  -lrte_pmd_ring -lethdev -lrte_malloc
>
> And now almost all symbols in .so file are defined (missing only
> rte_hexdump).
>
> I thought this was gonna be it. But after using this library, pci probe-ing
> fails since I don't have any pmd drivers registered, and
> rte_eth_dev_count() returns 0.
>
> But how are drivers supposed to be registered?
>
> When I use gdb with regular dpdk app (not shared library), I can see this:
> #0  0x000000000046fab0 in rte_eal_driver_register ()
> #1  0x0000000000418fb7 in devinitfn_bond_drv ()
> #2  0x00000000004f15ed in __libc_csu_init ()
> #3  0x00007ffff6efee55 in __libc_start_main (main=0x41ee65 <main>, argc=1,
> argv=0x7fffffffe4f8, init=0x4f15a0 <__libc_csu_init>, fini=<optimized out>,
> rtld_fini=<optimized out>, stack_end=0x7fffffffe4e8) at
> libc-start.c:246
> #4  0x000000000041953c in _start ()
>
>
> Ok, if I'm not mistaken, it seems driver registration is called before
> main. How is this accomplished? Cause in shared library build, I don't have
> this before main() and after rte_eal_init() (since driver list is empty)
> everything else fails.
>
> Any suggestions please? I'd really appreciate it...
>
> BR,
> Newman P.
>