Log error when pipe creation fails

This commit fixes the remaining buffer issues by introducing a little more complexity. It shall be refactored in the future to decrease complexity again, but for now, it works well and function is more important than form at this point.

CC #143

.gitmodules

@@ -1,6 +1,3 @@
-[submodule "lib/cpp-subprocess"]
-	path = lib/cpp-subprocess
-	url = https://github.com/arun11299/cpp-subprocess.git
 [submodule "lib/args"]
 	path = lib/args
 	url = https://github.com/Taywee/args.git

.travis.yml

@@ -1,9 +1,10 @@
 language: cpp
-sudo: required
 
 matrix:
   include:
-    - env: ARCH=x86_64
+    - name: Ubuntu bionic x86_64 release build
+      env: ARCH=x86_64
+      dist: bionic
       addons:
         apt:
           update: true
@@ -12,78 +13,66 @@ matrix:
             - libjpeg-dev
             - libpng-dev
             - cimg-dev
-            - automake  # required for patchelf
-    - env: ARCH=i386
-      addons:
-        apt:
-          update: true
-          packages:
-            - libmagic-dev:i386
-            - libjpeg-dev:i386
-            - libpng-dev:i386
-            - gcc-multilib
-            - g++-multilib
-            - automake  # required for patchelf
-            - libfuse2:i386
-            - libcairo2:i386
-    - env: ARCH=x86_64 BUILD_TYPE=coverage
-      addons:
-        apt:
-          update: true
-          packages:
-            - libmagic-dev
-            - libjpeg-dev
-            - libpng-dev
-            - cimg-dev
-      before_script:
-        - sudo pip install gcovr
-      script: travis/test-coverage.sh
-      after_success: true  # also, we don't intend to upload release binaries
-    - env: ARCH=i386 BUILD_TYPE=coverage
-      addons:
-        apt:
-          update: true
-          packages:
-            - libmagic-dev:i386
-            - libjpeg-dev:i386
-            - libpng-dev:i386
-            - gcc-multilib
-            - g++-multilib
-            - libfuse2:i386
-            - libcairo2:i386
-      before_script:
-        - sudo pip install gcovr
-      script: travis/test-coverage.sh
-      after_success: true  # also, we don't intend to upload release binaries
-    - env: ARCH=x86_64 BUILD_TYPE=centos6
-      services:
-        - docker
-      script: travis/build-centos6-docker.sh
+      script: travis/build.sh
       after_success:
         - if [ "$TRAVIS_BRANCH" != "$TRAVIS_TAG" ] && [ "$TRAVIS_BRANCH" != "master" ]; then export TRAVIS_EVENT_TYPE=pull_request; fi
         - wget -c https://github.com/probonopd/uploadtool/raw/master/upload.sh
-        - bash upload.sh linuxdeploy-centos6-"$ARCH".AppImage*
+        - bash upload.sh linuxdeploy-"$ARCH".AppImage*
 
-install:
-  - git clone https://github.com/NixOS/patchelf.git -b 0.8
-  - cd patchelf
-  - ./bootstrap.sh
-  - if [ "$ARCH" == "i386" ]; then ./configure --prefix=/usr --build=i686-pc-linux-gnu CFLAGS=-m32 CXXFLAGS=-m32 LDFLAGS=-m32; fi
-  - if [ "$ARCH" == "x86_64" ]; then ./configure --prefix=/usr; fi
-  - make -j$(nproc)
-  - sudo make install
-  - cd ..
-  - rm -rf patchelf
+    - name: Ubuntu bionic i386 build
+      env: ARCH=i386
+      dist: bionic
+      addons:
+        apt:
+          update: true
+          packages:
+            - libmagic-dev:i386
+            - libjpeg-dev:i386
+            - libpng-dev:i386
+            - gcc-multilib
+            - g++-multilib
+            - libfuse2:i386
+            - libcairo2:i386
+      script: travis/build.sh
+      after_success:
+        - if [ "$TRAVIS_BRANCH" != "$TRAVIS_TAG" ] && [ "$TRAVIS_BRANCH" != "master" ]; then export TRAVIS_EVENT_TYPE=pull_request; fi
+        - wget -c https://github.com/probonopd/uploadtool/raw/master/upload.sh
+        - bash upload.sh linuxdeploy-"$ARCH".AppImage*
 
-script:
-  - travis/build.sh
+    - name: Ubuntu xenial x86_64 coverage build (no binaries uploaded)
+      env: ARCH=x86_64 BUILD_TYPE=coverage
+      dist: xenial
+      addons:
+        apt:
+          update: true
+          packages:
+            - libmagic-dev
+            - libjpeg-dev
+            - libpng-dev
+            - cimg-dev
+      before_script:
+        - sudo pip install gcovr
+      script: travis/test-coverage.sh
+      after_success: true  # also, we don't intend to upload release binaries
 
-after_success:
-  - ls -lh
-  # make sure only pushes to rewrite create a new release, otherwise pretend PR and upload to transfer.sh
-  - if [ "$TRAVIS_BRANCH" != "$TRAVIS_TAG" ] && [ "$TRAVIS_BRANCH" != "master" ]; then export TRAVIS_EVENT_TYPE=pull_request; fi
-  - wget -c https://github.com/probonopd/uploadtool/raw/master/upload.sh
-  - bash upload.sh linuxdeploy-"$ARCH".AppImage*
+    - name: Ubuntu xenial i386 coverage build (no binaries uploaded)
+      env: ARCH=i386 BUILD_TYPE=coverage
+      dist: xenial
+      addons:
+        apt:
+          update: true
+          packages:
+            - libmagic-dev:i386
+            - libjpeg-dev:i386
+            - libpng-dev:i386
+            - gcc-multilib
+            - g++-multilib
+            - libfuse2:i386
+            - libcairo2:i386
+      before_script:
+        - sudo pip install gcovr
+      script: travis/test-coverage.sh
+      after_success: true  # also, we don't intend to upload release binaries
 
 branches:
   except:

CMakeLists.txt

@@ -10,11 +10,6 @@ set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} "${PROJECT_SOURCE_DIR}/cmake/Modules/
 set(USE_SYSTEM_BOOST OFF CACHE BOOL "Set to ON to use system boost libraries instead of building up to date boost libraries from source")
 set(USE_SYSTEM_CIMG ON CACHE BOOL "Set to OFF to use CImg library bundled in lib directory")
 
-if (EXISTS "${PROJECT_SOURCE_DIR}/lib/cpp-subprocess/subprocess.hpp")
-else()
-  message (FATAL_ERROR "Missing submodule(s), please 'git submodule update --init --recursive'...")
-endif()
-
 # support for ccache
 # call CMake with -DUSE_CCACHE=ON to make use of it
 set(USE_CCACHE ON CACHE BOOL "")

README.md

@@ -16,7 +16,7 @@ linuxdeploy was greatly influenced by [linuxdeployqt](https://github.com/probono
 
 ## User guides and examples
 
-Please see the [linuxdeploy user guide](https://docs.appimage.org/packaging-guide/linuxdeploy-user-guide.html) and the [native binaries packaging guide](https://docs.appimage.org/packaging-guide/native-binaries.html) in the [AppImage documentation](https://docs.appimage.org). There's also an [examples section](https://docs.appimage.org/packaging-guide/native-binaries.html#examples).
+Please see the [linuxdeploy user guide](https://docs.appimage.org/packaging-guide/from-source/linuxdeploy-user-guide.html) and the [native binaries packaging guide](https://docs.appimage.org/packaging-guide/from-source/native-binaries.html) in the [AppImage documentation](https://docs.appimage.org). There's also an [examples section](https://docs.appimage.org/packaging-guide/from-source/native-binaries.html#examples).
 
 
 ## Projects using linuxdeploy
@@ -28,6 +28,8 @@ This is an incomplete list of projects using linuxdeploy. You might want to read
 - [OpenRCT2](https://github.com/OpenRCT2/OpenRCT2)
 - [AppImageUpdate](https://github.com/AppImage/AppImageUpdate)
 - [appimaged](https://github.com/AppImage/appimaged)
+- [MediaElch](https://github.com/Komet/MediaElch/)
+- [CPU-X](https://github.com/X0rg/CPU-X) (details available [here](https://github.com/AppImage/AppImageKit/wiki/Bundling-GTK3-apps#fully-automated-deployment-from-sources-with-github-actions-cpu-x))
 
 
 ## Plugins

cmake/Modules/FindCImg.cmake

@@ -1,8 +1,35 @@
 # required for PNG imported target
-cmake_minimum_required(VERSION 3.5)
+cmake_minimum_required(VERSION 3.6)
 
-find_package(PNG REQUIRED)
-find_package(JPEG REQUIRED)
+find_package(PkgConfig)
+pkg_check_modules(libpng REQUIRED IMPORTED_TARGET libpng)
+
+# build custom static version of libjpeg for static builds
+if(STATIC_BUILD)
+    include(ExternalProject)
+
+    if($ENV{ARCH} MATCHES "i[356]86")
+        set(configure_command_prefix env CFLAGS=-m32 CXXFLAGS=-m32)
+    endif()
+
+    ExternalProject_Add(libjpeg_static_extproj
+        URL https://www.ijg.org/files/jpegsrc.v9d.tar.gz
+        URL_HASH SHA256=99cb50e48a4556bc571dadd27931955ff458aae32f68c4d9c39d624693f69c32
+        BUILD_IN_SOURCE ON
+        EXCLUDE_FROM_ALL ON
+        CONFIGURE_COMMAND ${configure_command_prefix} ./configure --prefix=/usr
+        INSTALL_COMMAND ""
+    )
+
+    ExternalProject_Get_property(libjpeg_static_extproj SOURCE_DIR)
+    add_library(libjpeg_static INTERFACE IMPORTED)
+    set_property(TARGET libjpeg_static PROPERTY INTERFACE_LINK_LIBRARIES ${SOURCE_DIR}/.libs/libjpeg.a)
+    add_dependencies(libjpeg_static libjpeg_static_extproj)
+
+    set(JPEG_LIBRARIES libjpeg_static)
+else()
+    find_package(JPEG REQUIRED)
+endif()
 
 if(NOT USE_SYSTEM_CIMG)
     message(STATUS "Using bundled CImg library")
@@ -22,7 +49,16 @@ else()
     endif()
 endif()
 
+set(PNG_INCLUDE_DIR ${libpng_INCLUDE_DIRS})
+if(NOT STATIC_BUILD)
+    set(PNG_LIBRARY ${libpng_LIBRARIES})
+else()
+    set(PNG_LIBRARY ${libpng_STATIC_LIBRARIES})
+endif()
+
+#message(FATAL_ERROR "${PNG_LIBRARY}")
+
 add_library(CImg INTERFACE)
-set_property(TARGET CImg PROPERTY INTERFACE_INCLUDE_DIRECTORIES "${CIMG_H_DIR};${JPEG_INCLUDE_DIR}")
-set_property(TARGET CImg PROPERTY INTERFACE_LINK_LIBRARIES "PNG::PNG;${JPEG_LIBRARIES}")
+set_property(TARGET CImg PROPERTY INTERFACE_INCLUDE_DIRECTORIES "${CIMG_H_DIR};${PNG_INCLUDE_DIR};${JPEG_INCLUDE_DIR}")
+set_property(TARGET CImg PROPERTY INTERFACE_LINK_LIBRARIES "${PNG_LIBRARY};${JPEG_LIBRARIES}")
 set_property(TARGET CImg PROPERTY INTERFACE_COMPILE_DEFINITIONS "cimg_display=0;cimg_use_png=1;cimg_use_jpeg=1")

include/linuxdeploy/core/appdir.h

@@ -39,7 +39,7 @@ namespace linuxdeploy {
                     explicit AppDir(const std::string& path);
 
                     // creates basic directory structure of an AppDir in "FHS" mode
-                    bool createBasicStructure();
+                    bool createBasicStructure() const;
 
                     // deploy shared library
                     //
@@ -57,48 +57,59 @@ namespace linuxdeploy {
                     // deploy executable
                     bool deployExecutable(const boost::filesystem::path& path, const boost::filesystem::path& destination = "");
 
+                    // deploy dependencies for ELF file in AppDir, without copying it into the library dir
+                    //
+                    // the dependencies end up in the regular location
+                    bool deployDependenciesOnlyForElfFile(const boost::filesystem::path& elfFilePath, bool failSilentForNonElfFile = false);
+
                     // deploy desktop file
                     bool deployDesktopFile(const desktopfile::DesktopFile& desktopFile);
 
                     // deploy icon
                     bool deployIcon(const boost::filesystem::path& path);
 
+                    // deploy icon, changing its name to <target filename>.<ext>
+                    bool deployIcon(const boost::filesystem::path& path, const std::string& targetFilename);
+
                     // deploy arbitrary file
                     boost::filesystem::path deployFile(const boost::filesystem::path& from, const boost::filesystem::path& to);
 
+                    // copy arbitrary file (immediately)
+                    bool copyFile(const boost::filesystem::path& from, const boost::filesystem::path& to, bool overwrite = false) const;
+
                     // create an <AppDir> relative symlink to <target> at <symlink>.
-                    bool createRelativeSymlink(const boost::filesystem::path& target, const boost::filesystem::path& symlink);
+                    bool createRelativeSymlink(const boost::filesystem::path& target, const boost::filesystem::path& symlink) const;
 
                     // execute deferred copy operations
                     bool executeDeferredOperations();
 
                     // return path to AppDir
-                    boost::filesystem::path path();
+                    boost::filesystem::path path() const;
 
                     // create a list of all icon paths in the AppDir
-                    std::vector<boost::filesystem::path> deployedIconPaths();
+                    std::vector<boost::filesystem::path> deployedIconPaths() const;
 
                     // create a list of all executable paths in the AppDir
-                    std::vector<boost::filesystem::path> deployedExecutablePaths();
+                    std::vector<boost::filesystem::path> deployedExecutablePaths() const;
 
                     // create a list of all desktop file paths in the AppDir
-                    std::vector<desktopfile::DesktopFile> deployedDesktopFiles();
+                    std::vector<desktopfile::DesktopFile> deployedDesktopFiles() const;
 
                     // create symlinks for AppRun, desktop file and icon in the AppDir root directory
-                    bool createLinksInAppDirRoot(const desktopfile::DesktopFile& desktopFile, boost::filesystem::path customAppRunPath = "");
+                    bool setUpAppDirRoot(const desktopfile::DesktopFile& desktopFile, boost::filesystem::path customAppRunPath = "");
 
                     // list all executables in <AppDir>/usr/bin
                     // this function does not perform a recursive search, but only searches the bin directory
-                    std::vector<boost::filesystem::path> listExecutables();
+                    std::vector<boost::filesystem::path> listExecutables() const;
 
                     // list all shared libraries in <AppDir>/usr/lib
                     // this function recursively searches the entire lib directory for shared libraries
-                    std::vector<boost::filesystem::path> listSharedLibraries();
+                    std::vector<boost::filesystem::path> listSharedLibraries() const;
 
                     // search for executables and libraries and deploy their dependencies
                     // calling this function can turn sure file trees created by make install commands into working
                     // AppDirs
-                    bool deployDependenciesForExistingFiles();
+                    bool deployDependenciesForExistingFiles() const;
 
                     // disable deployment of copyright files for this instance
                     void setDisableCopyrightFilesDeployment(bool disable);

include/linuxdeploy/core/log.h

@@ -65,6 +65,8 @@ namespace linuxdeploy {
                     ldLog operator<<(stdEndlType strm);
                     ldLog operator<<(const LD_LOGLEVEL logLevel);
                     ldLog operator<<(const LD_STREAM_CONTROL streamControl);
+
+                    void write(const char* s, const size_t n);
             };
         }
     }

include/linuxdeploy/plugin/base_impl.h

@@ -2,16 +2,19 @@
 #include <set>
 #include <string>
 #include <vector>
+#include <fcntl.h>
 #include <poll.h>
 
 // library headers
 #include <boost/filesystem.hpp>
 #include <fnmatch.h>
-#include <subprocess.hpp>
+#include <thread>
 
 // local headers
 #include "linuxdeploy/core/log.h"
 #include "linuxdeploy/util/util.h"
+#include "linuxdeploy/subprocess/process.h"
+#include "linuxdeploy/plugin/plugin_process_handler.h"
 
 #pragma once
 
@@ -46,19 +49,20 @@ namespace linuxdeploy {
 
                 private:
                     int getApiLevelFromExecutable() {
-                        auto output = subprocess::check_output({pluginPath.c_str(), "--plugin-api-version"});
-                        std::string stdoutOutput = output.buf.data();
+                        const auto arg =  "--plugin-api-version";
 
-                        // only interpret last line (fixes issues with --appimage-extract-and-run, where the runtime
-                        // prints all the paths it extracts out to stdout)
-                        const auto& lines = util::splitLines(stdoutOutput);
-                        const auto& lastLine = lines.back();
+                        const subprocess::subprocess proc({pluginPath.string(), arg});
+                        const auto stdoutOutput = proc.check_output();
+
+                        if (stdoutOutput.empty()) {
+                            ldLog() << LD_WARNING << "received empty response from plugin" << pluginPath << "while trying to fetch data for" <<  "--plugin-api-version" << std::endl;
+                            return -1;
+                        }
 
                         try {
-                            const auto pluginApiLevel = std::stoi(lastLine);
-                            return pluginApiLevel;
-                        } catch (const std::invalid_argument&) {
-                            ldLog() << LD_DEBUG << "Failed to understand plugin response:" << lastLine << std::endl;
+                            auto apiLevel = std::stoi(stdoutOutput);
+                            return apiLevel;
+                        } catch (const std::exception&) {
                             return -1;
                         }
                     }
@@ -69,9 +73,8 @@ namespace linuxdeploy {
 
                         // check whether plugin implements --plugin-type
                         try {
-                            auto output = subprocess::check_output({pluginPath.c_str(), "--plugin-type"});
-
-                            std::string stdoutOutput = output.buf.data();
+                            const subprocess::subprocess proc({pluginPath.c_str(), "--plugin-type"});
+                            const auto stdoutOutput = proc.check_output();
 
                             // the specification requires a single line, but we'll silently accept more than that, too
                             if (std::count(stdoutOutput.begin(), stdoutOutput.end(), '\n') >= 1) {
@@ -82,7 +85,7 @@ namespace linuxdeploy {
                                 else if (firstLine == "output")
                                     type = OUTPUT_TYPE;
                             }
-                        } catch (const subprocess::CalledProcessError&) {}
+                        } catch (const std::logic_error&) {}
 
                         return type;
                     }
@@ -94,12 +97,7 @@ namespace linuxdeploy {
 
                 if (d->apiLevel != API_LEVEL) {
                     std::stringstream msg;
-                    if (d->apiLevel < 0) {
-                        msg << "Could not read plugin API level";
-                    } else {
-                        msg << "This class only supports API level " << API_LEVEL << ", not " << d->apiLevel;
-                    }
-
+                    msg << "This class only supports API level " << API_LEVEL << ", not " << d->apiLevel;
                     throw WrongApiLevelError(msg.str());
                 }
             }
@@ -138,134 +136,8 @@ namespace linuxdeploy {
 
             template<int API_LEVEL>
             int PluginBase<API_LEVEL>::run(const boost::filesystem::path& appDirPath) {
-                auto pluginPath = path();
-                auto args = {pluginPath.c_str(), "--appdir", appDirPath.string().c_str()};
-
-                auto log = ldLog();
-                log << "Running process:";
-                for (const auto& arg : args) {
-                    log << "" << arg;
-                }
-                log << std::endl;
-
-                auto process = subprocess::Popen(args, subprocess::output{subprocess::PIPE}, subprocess::error{subprocess::PIPE});
-
-
-                std::vector<pollfd> pfds(2);
-                auto* opfd = &pfds[0];
-                auto* epfd = &pfds[1];
-
-                opfd->fd = fileno(process.output());
-                opfd->events = POLLIN;
-
-                epfd->fd = fileno(process.error());
-                epfd->events = POLLIN;
-
-                for (const auto& fd : {process.output(), process.error()}) {
-                    auto flags = fcntl(fileno(fd), F_GETFL, 0);
-                    flags |= O_NONBLOCK;
-                    fcntl(fileno(fd), F_SETFL, flags);
-                }
-
-                auto printOutput = [&pfds, opfd, epfd, this, &process]() {
-                    poll(pfds.data(), pfds.size(), -1);
-
-                    auto printUntilLastLine = [this](std::vector<char>& buf, size_t& bufSize, const std::string& streamType) {
-                        std::ostringstream oss;
-
-                        while (true) {
-                            const auto firstLineFeed = std::find(buf.begin(), buf.end(), '\n');
-                            const auto firstCarriageReturn = std::find(buf.begin(), buf.end(), '\r');
-
-                            if (firstLineFeed == buf.end() && firstCarriageReturn == buf.end())
-                                break;
-                            
-                            const auto endOfLine = std::min(firstLineFeed, firstCarriageReturn);
-
-                            std::string line(buf.begin(), endOfLine+1);
-
-                            oss << "[" << d->name << "/" << streamType << "] " << line;
-
-                            bufSize -= std::distance(buf.begin(), endOfLine+1);
-                            buf.erase(buf.begin(), endOfLine+1);
-                        }
-
-                        auto messages = oss.str();
-                        if (!messages.empty())
-                            ldLog() << messages;
-                    };
-
-                    std::vector<char> stdoutBuf(16 * 1024);
-                    std::vector<char> stderrBuf(16 * 1024);
-                    size_t stdoutBufSize = 0;
-                    size_t stderrBufSize = 0;
-
-                    if (opfd->revents & POLLIN) {
-                        if (stdoutBufSize >= stdoutBuf.size())
-                            throw std::runtime_error("Buffer overflow");
-
-                        while (true) {
-                            auto bytesRead = fread(
-                                reinterpret_cast<void*>(stdoutBuf.data() + stdoutBufSize),
-                                sizeof(char),
-                                static_cast<size_t>(stdoutBuf.size() - stdoutBufSize),
-                                process.output()
-                            );
-
-                            if (bytesRead == 0)
-                                break;
-
-                            stdoutBufSize += bytesRead;
-
-                            printUntilLastLine(stdoutBuf, stdoutBufSize, "stdout");
-                        }
-                    }
-
-                    std::this_thread::sleep_for(std::chrono::milliseconds(50));
-
-                    if (epfd->revents & POLLIN) {
-                        if (stderrBufSize >= stderrBuf.size())
-                            throw std::runtime_error("Buffer overflow");
-
-                        while (true) {
-                            auto bytesRead = fread(
-                                reinterpret_cast<void*>(stderrBuf.data() + stderrBufSize),
-                                sizeof(char),
-                                static_cast<size_t>(stderrBuf.size() - stderrBufSize),
-                                process.error()
-                            );
-
-                            if (bytesRead == 0)
-                                break;
-
-                            stderrBufSize += bytesRead;
-
-                            printUntilLastLine(stderrBuf, stderrBufSize, "stderr");
-                        }
-                    }
-
-                    std::this_thread::sleep_for(std::chrono::milliseconds(50));
-
-                    return true;
-                };
-
-                int retcode;
-
-                do {
-                    if (!printOutput()) {
-                        ldLog() << LD_ERROR << "Failed to communicate with process" << std::endl;
-                        process.kill();
-                        return -1;
-                    }
-                } while ((retcode = process.poll()) < 0);
-
-                if (!printOutput()) {
-                    ldLog() << LD_ERROR << "Failed to communicate with process" << std::endl;
-                    process.kill();
-                    return -1;
-                }
-
-                return retcode;
+                plugin_process_handler handler(d->name, path());
+                return handler.run(appDirPath);
             }
         }
     }

include/linuxdeploy/plugin/plugin_process_handler.h

@@ -0,0 +1,19 @@
+#pragma once
+
+// library headers
+#include <boost/filesystem/path.hpp>
+
+namespace linuxdeploy {
+    namespace plugin {
+        class plugin_process_handler {
+        private:
+            std::string name_;
+            boost::filesystem::path path_;
+
+        public:
+            plugin_process_handler(std::string name, boost::filesystem::path path);
+
+            int run(const boost::filesystem::path& appDir) const;
+        };
+    }
+}

include/linuxdeploy/subprocess/pipe_reader.h

@@ -0,0 +1,36 @@
+#pragma once
+
+#include <string>
+#include <set>
+#include <vector>
+#include <poll.h>
+
+/**
+ * Reads from a pipe when data is available, and hands data to registered callbacks.
+ */
+class pipe_reader {
+private:
+    const int pipe_fd_;
+
+public:
+    /**
+     * Construct new instance from pipe file descriptor.
+     * @param pipe_fd file descriptor for pipe we will read from (e.g., a subprocess's stdout, stderr pipes)
+     */
+    explicit pipe_reader(int pipe_fd);
+
+    /**
+     * Read from pipe file descriptor and store data in buffer.
+     * This method is non-blocking, i.e., if there is no data to read, it returns immediately.
+     * Otherwise, it will read until either of the following conditions is met:
+     *
+     *     - no more data left in the pipe to be read
+     *     - buffer is completely filled
+     *
+     * On errors, a subprocess_error is thrown.
+     *
+     * @param buffer buffer to store read data into
+     * @returns amount of characters read from the pipe
+     */
+    size_t read(std::vector<std::string::value_type>& buffer) const;
+};

include/linuxdeploy/subprocess/process.h

@@ -0,0 +1,86 @@
+// system headers
+#include <unordered_map>
+#include <vector>
+#include <signal.h>
+
+// local headers
+#include "linuxdeploy/subprocess/subprocess.h"
+
+namespace linuxdeploy {
+    namespace subprocess {
+        class process {
+        private:
+            // child process ID
+            int child_pid_ = -1;
+
+            // pipes to child process's stdout/stderr
+            int stdout_fd_ = -1;
+            int stderr_fd_ = -1;
+
+            // process exited
+            bool exited_ = false;
+            // exit code -- will be initialized by close()
+            int exit_code_ = -1;
+
+            // these constants help make the pipe code more readable
+            static constexpr int READ_END_ = 0, WRITE_END_ = 1;
+
+            static std::vector<char*> make_args_vector_(const std::vector<std::string>& args);
+
+            static std::vector<char*> make_env_vector_(const subprocess_env_map_t& env);
+
+            static int check_waitpid_status_(int status);
+
+        public:
+            /**
+             * Create a child process.
+             * @param args parameters for process
+             * @param env additional environment variables (current environment will be copied)
+             */
+            process(std::initializer_list<std::string> args, const subprocess_env_map_t& env);
+
+            /**
+             * Create a child process.
+             * @param args parameters for process
+             * @param env additional environment variables (current environment will be copied)
+             */
+            process(const std::vector<std::string>& args, const subprocess_env_map_t& env);
+
+            ~process();
+
+            /**
+             * @return child process's ID
+             */
+            int pid() const;
+
+            /**
+             * @return child process's stdout file descriptor ID
+             */
+            int stdout_fd() const;
+
+
+            /**
+             * @return child process's stderr file descriptor ID
+             */
+            int stderr_fd() const;
+
+            /**
+             * Close all pipes and wait for process to exit.
+             * If process is not running any more, just returns exit code.
+             * @return child process's exit code
+             */
+            int close();
+
+            /**
+             * Kill underlying process with given signal. By default, SIGTERM is used to end the process.
+             */
+            void kill(int signal = SIGTERM) const;
+
+            /**
+             * Check whether process is still alive. Use close() to fetch exit code.
+             * @return true while process is alive, false otherwise
+             */
+            bool is_running();
+        };
+    }
+}

include/linuxdeploy/subprocess/subprocess.h

@@ -0,0 +1,32 @@
+#pragma once
+
+// system headers
+#include <cstdio>
+#include <unordered_map>
+#include <string>
+#include <utility>
+#include <vector>
+
+// local headers
+#include "subprocess_result.h"
+
+namespace linuxdeploy {
+    namespace subprocess {
+        typedef std::unordered_map<std::string, std::string> subprocess_env_map_t;
+
+        class subprocess {
+        private:
+            std::vector<std::string> args_{};
+            std::unordered_map<std::string, std::string> env_{};
+
+        public:
+            subprocess(std::initializer_list<std::string> args, subprocess_env_map_t env = {});
+
+            explicit subprocess(std::vector<std::string> args, subprocess_env_map_t env = {});
+
+            subprocess_result run() const;
+
+            std::string check_output() const;
+        };
+    }
+}

include/linuxdeploy/subprocess/subprocess_result.h

@@ -0,0 +1,37 @@
+#pragma once
+
+// system headers
+#include <cstdlib>
+#include <string>
+#include <utility>
+#include <vector>
+
+namespace linuxdeploy {
+    namespace subprocess {
+        typedef std::vector<std::string::value_type> subprocess_result_buffer_t;
+
+        /**
+         * Result of subprocess execution. Follows Value Object design pattern.
+         */
+        class subprocess_result {
+        private:
+            int exit_code_;
+            subprocess_result_buffer_t stdout_contents_;
+            subprocess_result_buffer_t stderr_contents_;
+
+        public:
+            subprocess_result(int exit_code, subprocess_result_buffer_t stdout_contents,
+                              subprocess_result_buffer_t stderr_contents);
+
+            int exit_code() const;
+
+            const subprocess_result_buffer_t& stdout_contents() const;
+
+            std::string stdout_string() const;
+
+            const subprocess_result_buffer_t& stderr_contents() const;
+
+            std::string stderr_string() const;
+        };
+    }
+}

include/linuxdeploy/util/assert.h

@@ -0,0 +1,17 @@
+#pragma once
+
+// system headers
+#include <stdexcept>
+
+namespace linuxdeploy {
+    namespace util {
+        namespace assert {
+            template<typename T>
+            void assert_not_empty(T container) {
+                if (container.empty()) {
+                    throw std::invalid_argument{"container must not be empty"};
+                }
+            }
+        }
+    }
+}

include/linuxdeploy/util/misc.h

@@ -1,5 +1,6 @@
 #pragma once
 
+// system headers
 #include <algorithm>
 #include <climits>
 #include <cstring>
@@ -8,6 +9,9 @@
 #include <unistd.h>
 #include <vector>
 
+// libraries
+#include <boost/filesystem.hpp>
+
 namespace linuxdeploy {
     namespace util {
         namespace misc {
@@ -87,6 +91,33 @@ namespace linuxdeploy {
 
                 return buf.data();
             }
+
+            // very simple but for our purposes good enough which like algorithm to find binaries in $PATH
+            static boost::filesystem::path which(const std::string& name) {
+                const auto* path = getenv("PATH");
+
+                namespace bf = boost::filesystem;
+
+                if (path == nullptr)
+                    return "";
+
+                for (const auto& binDir : split(path, ':')) {
+                    if (!bf::is_directory(binDir)) {
+                        continue;
+                    }
+
+                    for (bf::directory_iterator it(binDir); it != bf::directory_iterator{}; ++it) {
+                        const auto binary = it->path();
+
+                        if (binary.filename() == name) {
+                            // TODO: check if file is executable (skip otherwise)
+                            return binary;
+                        }
+                    }
+                }
+
+                return {};
+            };
         }
     }
 }

include/linuxdeploy/util/subprocess.h

@@ -1,19 +0,0 @@
-/**
- * Wrapper for cpp-subprocess. Provides additional convenience functions.
- */
-
-#pragma once
-
-// library includes
-#include <subprocess.hpp>
-
-namespace linuxdeploy {
-    namespace util {
-        namespace subprocess {
-            using namespace ::subprocess;
-
-            // Reads output channels of existing Popen object into buffers and returns the contents
-            std::pair<std::string, std::string> check_output_error(Popen& proc);
-        }
-    }
-}

include/linuxdeploy/util/util.h

@@ -1,10 +1,11 @@
 // local includes
-#include "misc.h"
-#include "subprocess.h"
+#include "linuxdeploy/util/assert.h"
+#include "linuxdeploy/util/misc.h"
 
 // import functions from misc module for convenience
 namespace linuxdeploy {
     namespace util {
         using namespace misc;
+        using namespace assert;
     }
 }

lib/CMakeLists.txt

@@ -1,10 +1,5 @@
 include(CTest)
 
-add_library(subprocess INTERFACE)
-target_sources(subprocess INTERFACE ${CMAKE_CURRENT_SOURCE_DIR}/cpp-subprocess/subprocess.hpp)
-target_include_directories(subprocess INTERFACE ${CMAKE_CURRENT_SOURCE_DIR}/cpp-subprocess)
-target_compile_options(subprocess INTERFACE "-Wno-deprecated")
-
 add_library(args INTERFACE)
 target_sources(args INTERFACE ${CMAKE_CURRENT_SOURCE_DIR}/args/args.hxx)
 target_include_directories(args INTERFACE args)