How to cross-compile an application with library dependencies for Yocto Linux?

问题

I wrote an application on my laptop (Ubuntu 14.04) that depends on GStreamer and would like to cross-compile it for my Yocto Linux target (iMX6S-Wandboard). How do I cross-compile the application so that it runs on the target board and is able to use the GStreamer libraries?

Thank you,

Toan

UDPATE:

My Makefile:

PACKAGES            = gstreamer-1.0

override CFLAGS     += `pkg-config --cflags $(PACKAGES)` -Wall -Wextra "-DDATADIR=\"$(DATADIR)/\"" -ffunction-sections -fdata-sections
override LIBS       += `pkg-config --libs $(PACKAGES)`
override LDFLAGS    += -Wl,--gc-sections

OBJS    = basic-tutorial-7.o
DEPS    = $(foreach file,$(OBJS),$(basename $(file)).d)
EXE     = basic-tutorial-7

DESTDIR     ?=
PREFIX      ?=  $(HOME)/.local/
BINDIR      ?=  $(PREFIX)bin
DATADIR     ?=  $(PREFIX)share/$(PKGNAME)

.PHONY : clean install uninstall

all:    $(EXE)

$(EXE)  :   $(OBJS)
    $(CC) -o $@ $(OBJS) $(LDFLAGS) $(LIBS)

$(OBJS) : %.o   :   %.c %.d
    @[ -d "$(@D)" ] || mkdir -p "$(@D)"
    $(CC) -c $(CFLAGS) $(CPPFLAGS) -o $@ $<

$(DEPS) : %.d : $(PROJECT_ROOT)%.c
    @[ -d "$(@D)" ] || mkdir -p "$(@D)"
    $(CC) $(CFLAGS) $(CPPFLAGS) -M -MF $@ -MT "$(basename $@).o" $<

clean:
    rm -fr $(EXE) $(OBJS) $(DEPS)

install : $(EXE)
    install -DT -m 0755 $(EXE) $(DESTDIR)$(BINDIR)/$(EXE)

uninstall :
    rm -v $(DESTDIR)$(BINDIR)/$(EXE)

ifneq ($(MAKECMDGOALS), clean)
-include $(DEPS)
endif

My *.bb file:

DESCRIPTION = "Basic Tutorial 7"
LICENSE = "CLOSED"
LIC_FILES_CHKSUM = ""

DEPENDS = "gstreamer1.0 pkgconfig-native gstreamer1.0-plugins-base"

FILES_${PN} += "${bindir}/basic-tutorial-7 ${bindir}/basic-tutorial-7"

EXTRA_OEMAKE += "DESTDIR=${D}/ DATADIR=${datadir}/basic-tutorial-7 BINDIR=${bindir}"

do_compile () {
    oe_runmake install
}

do_install () {
    oe_runmake clean
}

Build log:

$ devtool build basic-tutorial-7

NOTE: Starting bitbake server...
NOTE: Reconnecting to bitbake server...
NOTE: Retrying server connection (#1)...
Loading cache: 100% |############################################| Time: 0:00:00
Loaded 1298 entries from dependency cache.
Parsing recipes: 100% |##########################################| Time: 0:00:00
Parsing of 773 .bb files complete (772 cached, 1 parsed). 1299 targets, 63 skipped, 0 masked, 0 errors.
Loading cache: 100% |############################################| Time: 0:00:00
Loaded 1298 entries from dependency cache.
Parsing recipes: 100% |##########################################| Time: 0:00:00
Parsing of 773 .bb files complete (772 cached, 1 parsed). 1299 targets, 63 skipped, 0 masked, 0 errors.
NOTE: Resolving any missing task queue dependencies
Initialising tasks: 100% |#######################################| Time: 0:00:01
Sstate summary: Wanted 0 Found 0 Missed 0 Current 322 (0% match, 100% complete)
NOTE: Executing Tasks
NOTE: Setscene tasks completed
NOTE: Tasks Summary: Attempted 1480 tasks of which 1480 didn't need to be rerun and all succeeded.

Deploy log:

$ devtool deploy-target basic-tutorial-7 root@192.168.0.101

NOTE: Starting bitbake server...
NOTE: Reconnecting to bitbake server...
NOTE: Retrying server connection (#1)...
Loading cache: 100% |############################################| Time: 0:00:00
Loaded 1298 entries from dependency cache.
Parsing recipes: 100% |##########################################| Time: 0:00:00
Parsing of 773 .bb files complete (772 cached, 1 parsed). 1299 targets, 63 skipped, 0 masked, 0 errors.
ERROR: No files to deploy - have you built the basic-tutorial-7 recipe? If so, the install step has not installed any files.

回答1:

The Yocto eSDK allows you to cross-compile applications for your Yocto target on your PC using exactly the compiler and libraries used for the target itself. There is no need to add GCC to the target. The eSDK can be generated from a Yocto source tree, but since you have the source installed anyways, you don't need to install the eSDK and can build directly from the source. All of the this is not ARM specific but the general Yocto workflow to cross-compile for a specific Yocto target.

To do this, first setup the Yocto build environment as usual by changing into the Yocto directory, running source setup-environment yourbuilddir.

Then, run devtool add, pass the name of your application (will be used for the BitBake recipe) and the path to the existing source tree, e.g.:

devtool add myhelloworld /home/user/Projects/myhelloworld

This will automatically generate a recipe and add a layer named workspace to your Yocto source tree. The recipe will be named something like /yocto/source/path/yourbuilddir/workspace/recipes/myhelloworld/myhelloworld.bb. You can edit it by running

devtool edit-recipe myhelloworld

Prefix the command with something like EDITOR=gedit to use your favourite text editor. Modify the recipe to build your application correctly; BitBake will automatically determine whether to run make or CMake. An example using make would be:

DESCRIPTION = "My GStreamer Hello World"
LICENSE = "CLOSED"
LIC_FILES_CHKSUM = ""

DEPENDS = "gstreamer1.0 pkgconfig-native"
FILES_${PN} += "${bindir}/myhelloworld ${datadir}/myhelloworld"

EXTRA_OEMAKE += "DESTDIR=${D}/ DATADIR=${datadir}/myhelloworld BINDIR=${bindir}"

do_install() {
    oe_runmake install
}

do_clean() {
    oe_runmake clean
}

DEPENDS lists the dependencies, I added gstreamer1.0 and also pkgconfig-native which is neccessary when using pkg-config inside the Makefile. You can add more dependencies to DEPENDS if you need them, for example boost openssl. A suitable example makefile would be:

PACKAGES            = gstreamer-1.0

override CFLAGS     += `pkg-config --cflags $(PACKAGES)` -Wall -Wextra "-DDATADIR=\"$(DATADIR)/\"" -ffunction-sections -fdata-sections
override LIBS       += `pkg-config --libs $(PACKAGES)`
override LDFLAGS    += -Wl,--gc-sections

OBJS    = main.o
DEPS    = $(foreach file,$(OBJS),$(basename $(file)).d)
EXE     = myhelloworld

DESTDIR     ?=
PREFIX      ?=  $(HOME)/.local/
BINDIR      ?=  $(PREFIX)bin
DATADIR     ?=  $(PREFIX)share/$(PKGNAME)

.PHONY : clean install uninstall

all:    $(EXE)

$(EXE)  :   $(OBJS)
    $(CC) -o $@ $(OBJS) $(LDFLAGS) $(LIBS)

$(OBJS) : %.o   :   %.c %.d
    @[ -d "$(@D)" ] || mkdir -p "$(@D)"
    $(CC) -c $(CFLAGS) $(CPPFLAGS) -o $@ $<

$(DEPS) : %.d : $(PROJECT_ROOT)%.c
    @[ -d "$(@D)" ] || mkdir -p "$(@D)"
    $(CC) $(CFLAGS) $(CPPFLAGS) -M -MF $@ -MT "$(basename $@).o" $<

clean:
    rm -fr $(EXE) $(OBJS) $(DEPS)

install : $(EXE)
    install -DT -m 0755 $(EXE) $(DESTDIR)$(BINDIR)/$(EXE)

uninstall :
    rm -v $(DESTDIR)$(BINDIR)/$(EXE)

ifneq ($(MAKECMDGOALS), clean)
-include $(DEPS)
endif

Inside your Makefile, make sure that make install installs your application binary into $(DESTDIR)$(BINDIR)/myhelloworld and data files (e.g. images) into $(DESTDIR)$(DATADIR)/somefile. On the target, your binary will then be located in /usr/bin/myhelloworld and the data files in /usr/share/myhelloworld. In the Makefile, pass "-DDATADIR=\"$(DATADIR)/\"" to the compiler such that you can open your data files by something like fopen(DATADIR "somepic.png", "rb");. For the source file main.c, you can use the GStreamer example 1.

Save recipe, Makefile and main.c, and then run

devtool build myhelloworld

to compile your application. If all goes well, you can then install it to the target via SSH by running e.g.

devtool deploy-target myhelloworld root@targethostname

You can then SSH to the target and run your application by typing myhelloworld. To uninstall it:

devtool undeploy-target myhelloworld root@targethostname

If you later decide to ship your application as part of the Yocto image, modify the recipe for your system image and add:

IMAGE_INSTALL_append = " yourhelloworld"

Keep the space after the first quote. When building the image, your application and data will be included. The main advantage of this approach (using a BitBake recipe) is that adding the application to the image becomes easy, and that the application will be linked against exactly the libraries available on the target, so you can use exactly the features present in these versions.

Using the example makefile above, you can also directly compile for your host PC by simply running make.

来源：https://stackoverflow.com/questions/60815312/how-to-cross-compile-an-application-with-library-dependencies-for-yocto-linux

标签

gcc

cross-compiling

gstreamer

yocto