> On Feb 14, 2018, at 9:34 PM, Jeffrey Helt <[email protected]> wrote: > > >> On Feb 14, 2018, at 8:08 PM, Stephen Hemminger <[email protected]> >> wrote: >> >> On Wed, 14 Feb 2018 19:06:03 -0500 >> Jeffrey Helt <[email protected]> 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. > > Using `export > LD_LIBRARY_PATH="/users/jhelt/dpdk/x86_64-native-linuxapp-gcc/lib/librte_eal.so”` > before building and/or running doesn’t seem to change anything. Using ldd, I > noticed that no dpdk shared objects are required by my library (see below), > which seems like a more fundamental issue to me, although admittedly I am not > that experienced in debugging linking issues. > > $ ldd ./build/lib/libshim.so > linux-vdso.so.1 => (0x00007fff907e2000) > libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007fe76b06a000) > /lib64/ld-linux-x86-64.so.2 (0x00007fe76b636000) > > Jeff
I managed to solve this issue. For future reference for anyone facing a similar issue, I needed to update the Makefile to the following. Note the LDLIBS. The "LDFLAGS += --no-undefined” was helpful in debugging missing symbols but is not required. After this change, I still needed to add the DPDK lib directory to my LD_LIBRARY_PATH as Stephen suggested. Jeff 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 LDFLAGS += --no-undefined LDLIBS += -ldl -l:librte_eal.so include $(RTE_SDK)/mk/rte.extshared.mk
