Re: [dpdk-users] Building a shared library that uses DPDK

[Stephen Hemminger <stephen@networkplumber.org>]

On Wed, 14 Feb 2018 19:06:03 -0500
Jeffrey Helt <jhelt@andrew.cmu.edu> wrote:

> Hi,
> 
> I am attempting to build a shared library that uses DPDK, specifically that wraps the Linux socket API and backs it by shared memory DPDK shared memory regions. I built DPDK 17.11 with “CONFIG_RTE_BUILD_SHARED_LIB=y”. In my shared library directory, I am using the following Makefile:
> 
> ifeq ($(RTE_SDK),)
> $(error "Please define RTE_SDK environment variable")
> endif
> 
> # Default target, can be overridden by command line or environment
> RTE_TARGET ?= x86_64-native-linuxapp-gcc
> 
> include $(RTE_SDK)/mk/rte.vars.mk
> 
> # binary name
> SHARED = libshim.so
> 
> # all source are stored in SRCS-y
> SRCS-y := wrap_socket.c
> 
> CFLAGS += -O3
> 
> include $(RTE_SDK)/mk/rte.extshared.mk
> 
> However, whenever I try to use my library, such as with "LD_PRELOAD=./build/lib/libshim.so ./test”, I receive "symbol lookup error: ./build/lib/libshim.so: undefined symbol: rte_eal_init”. What am I missing?
> 
> Thank you in advance for help!
> 
> Jeff
The DPDK builds lots of little shared libraries.
You need to have all of them in your LD_LIBRARY_PATH and then add your socket wrapper.