I am working on a (mostly C/C++) build environment that should be relocatable to a different folder location and system.
This actually already works, but when using libtool archive (.la) files there are warnings about those files being relocated. Basically this error can be ignored and everything builds fine.
So I was wondering if it's possible to have a relative path in .la files (for at least the libdir setting), or if there is some kind of built-in variable that can be used to refer to the path containing the .la file (similar to ${pcfiledir} in pkg-config's .pc files).
Related
I'm porting a large project to linux. I wrote all the CMakeLists.txt files, and everything compiles in my machine.
For whatever reason we still use TFS. The old version, not git with TFS.
I'm working in my own branch, but that branch has no build definition for linux. Before I check in, I want to be sure that everything compiles on the server too. So I need to merge my branch to another one, and submit that shelve set to the build job.
In my machine everything compiles fine. But when I run the build in the server, applying a shelveset to the branch that has a linux build definition, I get an error from the build, saying
CMake Error at
/myproject/subproject/CMakeLists.txt:165 (add_library):
Cannot find source file:
/myproject/subproject/IInternalTransactionManager.h
Tried extensions .c .C .c++ .cc .cpp .cxx .cu .m .M .mm .h .hh .h++ .hm
.hpp .hxx .in .txx
Indeed, that file is not there. Cmake complains about the file not being in the sources directory, which is true, because it is in another directory. But the fact is that I'm not asking for it either! My CMakeFiles.txt file does not include that file. That file is a header which is used in a few files, contains only classes definitions (no implementations), and the directory in which myHeader.h resides has been defined in include_directories. My CMakeLists.txt looks something like this:
set(PROJECT_NAME project)
project(${PROJECT_NAME})
include_directories(
../_include
)
set(source_files
main.cpp
file_that_includes_myHeader.cpp
)
add_library( ${PROJECT_NAME} STATIC ${source_files} )
and my file structure is something like:
/myproject/subproject/main.cpp
/myproject/subproject/file_that_includes_myHeader.cpp
/myproject/subproject/CMakeLists.txt
/myproject/_include/myHeader.h
So, why should cmake complaining about a missing file, if such file is not included in the CMakeLists.txt file? And why would this happen only the build in TFS? My guess is that there is something wrong when applying the shelvetset and is not related to my code, but I cannot prove it.
I compared the code after the shelveset is applyied, and still in that version the CMakeLists.txt does not mention myHeader.h
Or, there is some rule about including headers in CMakeLists.txt files which I'm not aware of.
So, after expending too much debuging I contacted the team in charge of the build process. And as it turns out, the building process in the TFS building definition was definetly NOT what I expected. And of course this was not documented.
Our development is mostly in windows (by far). The linux build has a step before building: a script is launched which parses each Visual Studio project file, gets the included files, and substitutes the source files in the CMakeLists.txt files with the one parsed from VS. Right or wrong, is just the way it is.
I could build the linux build in my local machine because everything was done correctly. The windows build worked too, even though the VS project files sometimes included some files which were not in the source directory but in some header only directory, and somehow that compiled. I guess because the directory was defined in the include directory. But When the CMakeLists.txt files were updated, cmake complained (rightly so) about not finding the files.
So, if anybody experiences similar issues, contact your devops team or whoever is in charge of such things.
So I am working on a project that is intended to run on a remote server. I develop the program on a local pc, compile it, then upload it to the remote server. Both the local pc and the remote server are run on CentOS 7.7.
The program is developed using the CLion IDE, configured with CMake. The program depends a few shared libraries, which are supposed to link to the executable according to what I wrote in CMake. At my local PC, I can compile and run the program perfectly. However, after I scp the whole directory of the project to the remote server, the executable fails to run. It cannot find any of the ".so" files, according to what ldd says.
This is my CMakeList.txt, with every path being relative path, instead of absolute path.
cmake_minimum_required(VERSION 3.15)
project(YS_Test)
set(CMAKE_CXX_STANDARD 11)
set(SOURCE_PATH_ src)
file(GLOB SOURCE_FILES_ ${SOURCE_PATH_}/*.*)
set(PROJECT_LIBS_ libTapQuoteAPI.so libTapTradeAPI.so libTapDataCollectAPI.so)
include_directories(api/include)
link_directories(api/lib/linux)
add_executable(YS_Test ${SOURCE_FILES_})
target_link_libraries(YS_Test ${PROJECT_LIBS_})
Please do not tell me to set LD_LIBRARY_PATH to fix my issue. The program worked fine on my local pc without LD_LIBRARY_PATH, so I expect it to run on the remote server without LD_LIBRARY_PATH. I would like to know what is really going on here, instead of a work around. Thanks!
If I understand your problem correctly, you want to ship your compiled YS_Test program along with some dependencies and have it run on a remote server. By default an executable will only look in the directories configured in /etc/ld.so, which will not include the deploy path.
Note: Typically you do not deploy your entire build directory but only the compiled artifacts and dependencies. For this answer I will assume you deploy the binary and its dependencies to the same directory.
You have two options:
Require users of your program to set LD_LIBRARY_PATH, either by themselves or by a wrapper script. This variable will instruct the dynamic linker to look in the specified directories as well. Even if you do not like this solution, it is by far the most common approach.
Add -Wl,-rpath='$ORIGIN' to your linker options. This will add a DT_RUNPATH attribute to the executable's dynamic section. As you are using CMake you can also set this using BUILD_RPATH and/or INSTALL_RPATH target properties.
The ld.so manpage describes this attribute as follows:
If a shared object dependency does not contain a slash, then it is
searched for in the following order:
...
Using the directories specified in the DT_RUNPATH dynamic section
attribute of the binary if present.
The $ORIGIN part expands to the directory containing the program or shared
object.
If you really insist on shipping your build directory (eg during development), you can take a look at the CMake BUILD_RPATH_USE_ORIGIN property (and its usual global counterpart CMAKE_BUILD_RPATH_USE_ORIGIN), this will embed relative paths into binaries instead of absolute paths.
As you don't want a workaround (#Botje has given you two already), I will try an explanation instead. In your development machine, if you use this command:
ldd YS_Test
You will see all the shared libraries used by your program, with their corresponding paths. The libTapQuoteAPI.so libTapTradeAPI.so libTapDataCollectAPI.so are found at your 'api/lib/linux' directory, but resolved with full absolute paths. If you do the same at your server, some shared objects can't be resolved because they aren't at the same location.
If you use one of these commands (not sure which are available in Centos):
chrpath --list YS_Test
or
patchelf --print-rpath YS_Test
You will see the RPATH or RUNPATH tags embedded in your program. This is the path used by the Linux linker to locate dependencies that are outside the standard ld locations. You may find extended explanations on Internet about this, like this one or the Wikipedia article.
Breaking my promise, I give you a third workaround: use patchelf or chrpath at your server after scp to change the embedded RPATH tag, pointing it relative to $ORIGIN (which represents the program location).
I'm porting an SDK written in C++ from Windows to Linux. There are other binaries, but at its simplest, our SDK is this:
core.dll - implicitly loaded DLL ("libcore.so" shared library on Linux)
tests.exe - an app use to test the DLL (uses google test)
All of my binaries must live in one folder somewhere that apps can find. I've achieved that on Windows. I wanted to achieve the same thing in Linux. I'm failing miserably
To illustrate, Here's the basic project tree. We use CMake. After I build I've got
mysdk
|---CMakeLists.txt (has add_subdirectory() statements for "tests" and "core")
|---/tests (source code + CMakeLists.txt)
|---/core (source code + CMakeLists.txt)
|---/build (all build ouput, CMake output, etc)
|---tests (build output)
|---core (build output)
The goal is to "flatten" the "build" tree and put all the binary outputs of tests, core, etc into one folder.
I tried adding CMake's "install" command, to each of my CMakeLists.txt files (e.g. install(TARGETS core DESTINATION bin). I then then executed sudo make install after my normal build. This put all my binaries in /usr/local/bin with no errors. But when I ran tests from there, it failed to find libcore.so, even though it was sitting right there in the same folder
tests: error while loading shared libraries: libcore.so: Cannot open shared object file: No such file or directory
I read up on the LD_LIBRARY_PATH environment variable and so tried adding that folder (/usr/local/bin) into it and running. I can see I've properly altered LD_LIBRARY_PATH but it still doesn't work. "tests" still can't find libcore.so. I even tried changing the PATH environment variable as well. Same result.
In frustration, I tried brute-force copying the output binaries to a temporary subfolder (of /mysdk/build) and running tests from there. To my surprise it ran.
Then I realized why: Instead of loading the local copy of libcore.so it had loaded the one from the build output folder (as if the full path were "baked in" to the app at build time). Subsequently deleting that build-output copy of libcore.so made "tests" fail altogether as before, instead of loading the local copy. So maybe the path really was baked in.
I'm at a loss. I've read the CMake tutorial and reference. It makes this sound so easy. Aside from the obvious (What am I doing wrong?) I would appreciate if anyone could answer any of the following questions:
What is the correct way to control where my app looks for my shared libraries?
Is there a relationship between my project build structure and how my binaries must then appear when installed?
Am I even close to the right way of doing this?
Is it possible I've somehow inadvertently "baked" (into my app) full paths to my shared libraries? Is that a thing? I use all CMAKE variables in my CMakeLists files.
You can run ldd file to print the shared object dependencies for file. It will tell you where are its dependencies being read from.
You can export the environment variable LD_LIBRARY_PATH with the paths you want the linker to look for. If a dependency is not found, try adding the path where that dependency is located at to LD_LIBRARY_PATH and then run ldd again (make sure you export the variable).
Also, make sure the dependencies have the right permissions.
Updating LD_LIBRARY_PATH is an option. Another option is using RPATH. Please check the example.
https://github.com/mustafagonul/cmake-examples/blob/master/005-executable-with-shared-library/CMakeLists.txt
cmake_minimum_required(VERSION 2.8)
# Project
project(005-executable-with-shared-library)
# Directories
set(example_BIN_DIR bin)
set(example_INC_DIR include)
set(example_LIB_DIR lib)
set(example_SRC_DIR src)
# Library files
set(library_SOURCES ${example_SRC_DIR}/library.cpp)
set(library_HEADERS ${example_INC_DIR}/library.h)
set(executable_SOURCES ${example_SRC_DIR}/main.cpp)
# Setting RPATH
# See https://cmake.org/Wiki/CMake_RPATH_handling
set(CMAKE_INSTALL_RPATH ${CMAKE_INSTALL_PREFIX}/${example_LIB_DIR})
# Add library to project
add_library(library SHARED ${library_SOURCES})
# Include directories
target_include_directories(library PUBLIC ${CMAKE_CURRENT_SOURCE_DIR}/${example_INC_DIR})
# Add executable to project
add_executable(executable ${executable_SOURCES})
# Linking
target_link_libraries(executable PRIVATE library)
# Install
install(TARGETS executable DESTINATION ${example_BIN_DIR})
install(TARGETS library DESTINATION ${example_LIB_DIR})
install(FILES ${library_HEADERS} DESTINATION ${example_INC_DIR})
This should be really simple, but I'm having trouble. I want to include some shared Qt libraries with my application in the installation folder so the user doesn't have to download Qt separately. On Windows, this seemed to work fine, but Ubuntu complains about not being to find the Qt libraries when they are in the same folder as the application.
How do I add the installation directory to shared library search path?
I was able to add the installation directory to shared library search path by adding the following lines to the .pro file, which set the rpath of the binary to $ORIGIN (the install folder). I needed to add the location of QT libs on my current machine (/usr/lib/qt5.5 and /usr/lib/qt5.5/lib) so that the project would build in QtCreator.
unix:!macx {
# suppress the default RPATH if you wish
QMAKE_LFLAGS_RPATH=
# add your own with quoting gyrations to make sure $ORIGIN gets to the command line unexpanded
QMAKE_LFLAGS += "-Wl,-rpath,\'\$$ORIGIN\':/usr/lib/qt5.5:/usr/lib/qt5.5/lib"
}
(The unix:!macx line makes it apply to linux only)
Windows, Linux and OSX behave quite differently. Windows is easiest: dump all the dll's in the application dir. OSX is next and Linux is most difficult.
Linux has certain search paths for searching shared objects. These search paths are mainly system libraries and possibly some user libraries. As you do not want to mess around with system files of your user one would prefer to have the shared objects in the application dir. This is possible but you have to tell Linux to read that directory. You can do this with setting the environment variable LD_LIBRARY_PATH. You can do this with a script. See my answer.
I am trying to make a Qt5 part of my source tree, so I haven't installed it on my machine, just copied it from source control. I am having a problem when I try to run uic.exe:
stiopa#stiopa-VirtualBox:~/ct/LinuxLibs/Qt/bin > ./uic
./uic: error while loading shared libraries: libQt5Core.so.5: cannot open shared object file: No such file or directory
I am still getting the same error even when I copy the libQt5Core library to bin directory. How is uic looking for shared libraries? Is there any environment variable I need to set to fix it?
This is yet another case of not putting the dependent shared libraries in a defined location that is supported by the program.
If you're planning on doing the 'copy the files to the same directory as the executable', the fast solution is to reference the directory in the library load path; e.g. if the binary is in $HOME/foo, you do:
export LD_LIBRARY_PATH=${LD_LIBRARY_PATH}${LD_LIBRARY_PATH:+:}$HOME/foo
This adds or makes $HOME/foo the run-time-linker's load path. As a result, any programs you run will look in this directory for libraries, as well as the default set for the OS (defined by the ld.so configuration), as well as the paths that are defined within the application itself (the rpath).
If you're going to follow this route, what you can do is to move the binary to target.bin, create a target bash script, which invokes the bin file automatically; e.g.
#!/bin/bash -p
export LD_LIBRARY_PATH=${LD_LIBRARY_PATH}${LD_LIBRARY_PATH:+:}$(dirname $0)
exec $0.bin "$*"
A secondary mechanism which will permit you to change the search location for a binary; without requiring an environment variable insert is to modify the binary so that it searches in different locations than it usually does; this takes advantage of some features in the run-time linker (which looks for libraries).
There is a program called chrpath, which can be added by various package managers, which allows you to edit the rpath directly. In this case; you can change the additional search path of the binary using:
chrpath -r '$ORIGIN' foo
This means that the program will look in the same directory as the binary for .so files, thus allowing it to run.