Dear forum users,
this might be a very often asked question, but I am breaking my legs since 1-2 days and I dont get it.
I tried to build my c program with setting all up and running
mips-openwrt-linux-musl-gcc -o listen listen.c -L /home/frood/Documents/git/OpenWrt-V2X/staging_dir/toolchain-mips_24kc_gcc-7.3.0_musl/include/ -I /home/frood/Documents/git/OpenWrt-V2X/staging_dir/target-mips_24kc_musl/usr/include/ -l pcap
And at the end of everything, I ended up creating my own package.
I followed
https://openwrt.org/docs/guide-developer/helloworld/chapter5
And here is my Makefile:
include $(TOPDIR)/rules.mk
# Name, version and release number
# The name and version of your package are used to define the variable to point to the build directory of your package: $(PKG_BUILD_DIR)
PKG_NAME:=listen
PKG_VERSION:=1.0
PKG_RELEASE:=1
# Source settings (i.e. where to find the source codes)
# This is a custom variable, used below
SOURCE_DIR:=/home/frood/Documents/git/OpenWrt-V2X/listen
include $(INCLUDE_DIR)/package.mk
# Package definition; instructs on how and where our package will appear in the overall configuration menu ('make menuconfig')
define Package/listen
SECTION:=mypackages
CATEGORY:=v2x
TITLE:=listen
DEPENDS:=+libpcap
endef
# Package description; a more verbose description on what our package does
define Package/listen/description
Listening to V2X packets.
endef
# Package preparation instructions; create the build directory and copy the source code.
# The last command is necessary to ensure our preparation instructions remain compatible with the patching system.
define Build/Prepare
mkdir -p $(PKG_BUILD_DIR)
LDFLAGS=-lpcap
cp $(SOURCE_DIR)/* $(PKG_BUILD_DIR)
$(Build/Patch)
endef
# Package build instructions; invoke the target-specific compiler to first compile the source file, and then to link the file into the final executable
define Build/Compile
$(TARGET_CC) $(TARGET_CFLAGS) -o $(PKG_BUILD_DIR)/listen.o -c $(PKG_BUILD_DIR)/listen.c
$(TARGET_CC) $(TARGET_LDFLAGS) -o $(PKG_BUILD_DIR)/$1 $(PKG_BUILD_DIR)/listen.o
endef
# Package install instructions; create a directory inside the package to hold our executable, and then copy the executable we built previously into the folder
define Package/listen/install
$(INSTALL_DIR) $(1)/usr/bin
$(INSTALL_BIN) $(PKG_BUILD_DIR)/listen $(1)/usr/bin
endef
# This command is always the last, it uses the definitions and variables we give above in order to get the job done
$(eval $(call BuildPackage,listen))
A simple hello world works fine, but nit with libpcap.
BTW, libpcap is selected in the menuconfig:
General info: I am using the "famous" OpenWrt version of Francesco:
https://github.com/francescoraves483/OpenWrt-V2X
But this error is what I am ALWAYS getting. Always. Independent of which approach I try - with manual c cross compiling, with package....
mips-openwrt-linux-musl-gcc -L/home/frood/Documents/git/OpenWrt-V2X/staging_dir/target-mips_24kc_musl/usr/lib -L/home/frood/Documents/git/OpenWrt-V2X/staging_dir/target-mips_24kc_musl/lib -L/home/frood/Documents/git/OpenWrt-V2X/staging_dir/toolchain-mips_24kc_gcc-7.3.0_musl/usr/lib -L/home/frood/Documents/git/OpenWrt-V2X/staging_dir/toolchain-mips_24kc_gcc-7.3.0_musl/lib -znow -zrelro -o /home/frood/Documents/git/OpenWrt-V2X/build_dir/target-mips_24kc_musl/listen-1.0/listen /home/frood/Documents/git/OpenWrt-V2X/build_dir/target-mips_24kc_musl/listen-1.0/listen.o
/home/frood/Documents/git/OpenWrt-V2X/build_dir/target-mips_24kc_musl/listen-1.0/listen.o: In function `main':
listen.c:(.text.startup+0x36): undefined reference to `pcap_open_live'
listen.c:(.text.startup+0x52): undefined reference to `pcap_datalink'
listen.c:(.text.startup+0x60): undefined reference to `pcap_datalink'
listen.c:(.text.startup+0x6a): undefined reference to `pcap_datalink'
listen.c:(.text.startup+0x96): undefined reference to `pcap_compile'
listen.c:(.text.startup+0xa2): undefined reference to `pcap_geterr'
listen.c:(.text.startup+0xb4): undefined reference to `pcap_setfilter'
listen.c:(.text.startup+0xc0): undefined reference to `pcap_geterr'
listen.c:(.text.startup+0xd6): undefined reference to `pcap_loop'
listen.c:(.text.startup+0xdc): undefined reference to `pcap_close'
collect2: error: ld returned 1 exit status
make[2]: *** [Makefile:53: /home/frood/Documents/git/OpenWrt-V2X/build_dir/target-mips_24kc_musl/listen-1.0/.built] Error 1
I am confused about that the header files are fine and found - no error for
#include <pcap/pcap.h>
but for
session_handler = pcap_open_live(dev, 65535, 1, 1000, errbuf);
Is there anything I can do to solve this error?
Thanks and best regards, Food
