Qt

Sample

BugSplat has developed a sample application demonstrating a cross-platform Qt crash reporting solution with Crashpad. The MyQtCrasher sample application provides a good starting point for developers wishing to capture Windows, macOS, and Linux crashes. Additionally, the sample provides symbol upload scripts that you can incorporate into your build tools to generate crash reports with fully symbolicated call stacks

The MyQtCrasher sample application is available on GitHub.

Building Crashpad

BugSplat leverages Crashpad to provide crash reporting for macOS, Windows, and Linux Qt applications. Please see this article for an in-depth guide that discusses how to build Crashpad.

For Windows, you'll need to build shared libraries for both Release (/MD) and Debug (/MDd) configurations. You'll also want to consider building with Whole Program Optimization turned off (/GL-). To build shared libraries, generate your Crashpad build using the following terminal command:

gn gen out\MD --args="extra_cflags=\"/MD /GL-\"" && gn gen out\MDd --args="extra_cflags=\"/MDd /GL-\""

The snippet above works with Windows CMD, and depending on the terminal you're using, you might get various errors related to escape characters. If you choose to omit the /GL- flag you must ensure that you build Crashpad with the same version of MSVC you use for building your Qt application otherwise your project will not build. Setting the version of MSVC that builds Crashpad can be done by instead generating your configuration using the command gn gen out/Default --winsdk="10.0.19041.0" --ide="vs2017".

For more info on how to build Crashpad shared libraries on Windows, see this post.

Integrating Crashpad

Once Crashpad has been built, you'll need to add the relevant include directories to your project. Copy all of the Crashpad .h files to the directory $$PWD/Crashpad/Include/crashpad where $$PWD is your project's working directory. Add the include directories to your project by pasting the following snippet at the top of your project file:

# Include directories for Crashpad libraries
INCLUDEPATH += $$PWD/Crashpad/Include/crashpad
INCLUDEPATH += $$PWD/Crashpad/Include/crashpad/third_party/mini_chromium/mini_chromium
INCLUDEPATH += $$PWD/Crashpad/Include/crashpad/out/Default/gen

Add values corresponding to your BugSplat database, application name, and version. Note these values, as they will be used to configure Crashpad later in the configuration process.

# BugSplat configuration options
BUGSPLAT_DATABASE = fred            # Replace with your BugSplat database
BUGSPLAT_APPLICATION = myQtCrasher  # Replace with the name of your app
BUGSPLAT_VERSION = 1.1              # Replace with your apps version
BUGSPLAT_USER = fred@bugsplat.com   # Your BugSplat email (for uploading symbols)
BUGSPLAT_PASSWORD = Flintstone      # Your BugSplat password (for uploading symbols)

Next, link your app with the Crashpad libraries. Linking with the Crashpad libraries is platform-dependent.

macOS

Copy libcommon.a, libbase.a, libutil.a, libclient.a , and libmig_output.a into $$PWD/Crashpad/Libraries/MacOS. You'll need to link to versions of these libraries that were built to target either arm64 or x86_64 depending on which architecture your build targets. You'll also need to link with the system libraries libbsm, AppKit.Framework, and Security.Framework. Add the following snippet to your project file to link with the aforementioned libraries:

# Crashpad rules for MacOS
macx {
    # Choose either x86_64 or arm64
    #ARCH = x86_64
    ARCH = arm64

    # Crashpad libraries
    LIBS += -L$$PWD/Crashpad/Libraries/MacOS/$$ARCH -lcommon
    LIBS += -L$$PWD/Crashpad/Libraries/MacOS/$$ARCH -lclient
    LIBS += -L$$PWD/Crashpad/Libraries/MacOS/$$ARCH -lbase
    LIBS += -L$$PWD/Crashpad/Libraries/MacOS/$$ARCH -lutil
    LIBS += -L$$PWD/Crashpad/Libraries/MacOS/$$ARCH -lmig_output

    # System libraries
    LIBS += -L/usr/lib/ -lbsm
    LIBS += -framework AppKit
    LIBS += -framework Security
}

You'll need to include a copy of the crashpad_handler executable with your application. Again, be sure to copy the version of crashpad_handler that targets either arm64 or x86_64 depending on what architecture you're targeting.

Copy crashpad_handler to the $$PWD/Crashpad/Bin/MacOS directory. Add the following snippet to the macx section of your project file that copies the macOS crashpad_handler to your project's build directory.

# Crashpad rules for MacOS
macx {
    ...
    # Copy crashpad_handler to build directory
    QMAKE_POST_LINK += "mkdir -p $$OUT_PWD/crashpad"
    QMAKE_POST_LINK += "&& cp $$PWD/Crashpad/Bin/MacOS/crashpad_handler $$OUT_PWD/crashpad"
}

Windows

Copy base.lib, common.lib, client.lib and util.lib into $$PWD/Crashpad/Libraries/Windows. You'll need to link with the system library Advapi32. Add the following snippet to your project file to link with the aforementioned libraries:

# Crashpad rules for Windows
win32 {
    # Crashpad libraries
    LIBS += -L$$PWD/Crashpad/Libraries/Windows/ -lbase
    LIBS += -L$$PWD/Crashpad/Libraries/Windows/ -lcommon
    LIBS += -L$$PWD/Crashpad/Libraries/Windows/ -lclient
    LIBS += -L$$PWD/Crashpad/Libraries/Windows/ -lutil

    # System libraries
    LIBS += -lAdvapi32
}

Additionally, you'll need to ship a copy of the crashpad_handler.exe executable with your application.

Copy crashpad_handler.exe to the $$PWD/Crashpad/Bin/Windows directory. Add the following snippet to the win32 section of your project file that copies the Windows crashpad_handler.exe to your project's build directory.

# Crashpad rules for Windows
win32 {
    ...
    # Build variables
    CONFIG(debug, debug|release) {
        EXEDIR = $$OUT_PWD\debug
    }
    CONFIG(release, debug|release) {
        EXEDIR = $$OUT_PWD\release
    }

    # Copy crashpad_handler.exe to output directory
    QMAKE_POST_LINK += "copy /y $$shell_path($$PWD)\Crashpad\Bin\Windows\crashpad_handler.exe $$shell_path($$OUT_PWD)\crashpad"
}

Linux

Copy libbase.a, libutil.a, libcommon.a and libclient.a into $$PWD/Crashpad/Libraries/Linux. The order in which you specify the Crashpad libraries to link is important! libcommon.a, and libclient.a must be specified first, then libutil.a and finally libbase.a. Add the following snippet to your project file to link with the aforementioned libraries:

# Crashpad rules for Linux
linux {
    # Crashpad libraries
    LIBS += -L$$PWD/Crashpad/Libraries/Linux/ -lcommon
    LIBS += -L$$PWD/Crashpad/Libraries/Linux/ -lclient
    LIBS += -L$$PWD/Crashpad/Libraries/Linux/ -lutil
    LIBS += -L$$PWD/Crashpad/Libraries/Linux/ -lbase
}

Additionally, you'll need to ship a copy of the crashpad_handler executable with your application. Copy crashpad_handler to the $$PWD/Crashpad/Bin/Linux directory. Add the following snippet to the linux section of your project file that copies the Linux crashpad_handler to your project's build directory.

# Crashpad rules for Linux
linux {
    ...
    # Copy crashpad_handler to build directory
    QMAKE_POST_LINK += "cp $$PWD/Crashpad/Bin/Linux/crashpad_handler $$OUT_PWD/crashpad"
}

Configuring Crashpad

To enable Crashpad in your application, you must configure the Crashpad handler with your BugSplat database, application name, and application version. The following is a macOS, Windows, and Linux-compatible snippet that will configure the Crashpad handler:

#include <QApplication>
#include <vector>
#include "paths.h"
#include "client/crash_report_database.h"
#include "client/crashpad_client.h"
#include "client/settings.h"

using namespace base;
using namespace crashpad;

bool initializeCrashpad(QString dbName, QString appName, QString appVersion);
QString getExecutableDir(void);

bool initializeCrashpad(QString dbName, QString appName, QString appVersion)
{
    // Get directory where the exe lives so we can pass a full path to handler, reportsDir and metricsDir
    QString exeDir = getExecutableDir();

    // Helper class for cross-platform file systems
    Paths crashpadPaths(exeDir);

    // Ensure that crashpad_handler is shipped with your application
    FilePath handler(Paths::getPlatformString(crashpadPaths.getHandlerPath()));

    // Directory where reports will be saved. Important! Must be writable or crashpad_handler will crash.
    FilePath reportsDir(Paths::getPlatformString(crashpadPaths.getReportsPath()));

    // Directory where metrics will be saved. Important! Must be writable or crashpad_handler will crash.
    FilePath metricsDir(Paths::getPlatformString(crashpadPaths.getMetricsPath()));

    // Configure url with your BugSplat database
    QString url = "https://" + dbName + ".bugsplat.com/post/bp/crash/crashpad.php";

    // Metadata that will be posted to BugSplat
    QMap<std::string, std::string> annotations;
    annotations["format"] = "minidump";                 // Required: Crashpad setting to save crash as a minidump
    annotations["database"] = dbName.toStdString();     // Required: BugSplat database
    annotations["product"] = appName.toStdString();     // Required: BugSplat appName
    annotations["version"] = appVersion.toStdString();  // Required: BugSplat appVersion
    annotations["key"] = "Sample key";                  // Optional: BugSplat key field
    annotations["user"] = "fred@bugsplat.com";          // Optional: BugSplat user email
    annotations["list_annotations"] = "Sample comment";	// Optional: BugSplat crash description

    // Disable crashpad rate limiting so that all crashes have dmp files
    std::vector<std::string> arguments;
    arguments.push_back("--no-rate-limit");

    // Initialize crashpad database
    std::unique_ptr<CrashReportDatabase> database = CrashReportDatabase::Initialize(reportsDir);
    if (database == NULL) return false;

    // Enable automated crash uploads
    Settings *settings = database->GetSettings();
    if (settings == NULL) return false;
    settings->SetUploadsEnabled(true);

    // Attachments to be uploaded alongside the crash - default bundle size limit is 20MB
    std::vector<FilePath> attachments;
    FilePath attachment(Paths::getPlatformString(crashpadPaths.getAttachmentPath()));
#if defined(Q_OS_WINDOWS) || defined(Q_OS_LINUX)
    // Crashpad hasn't implemented attachments on OS X yet
    attachments.push_back(attachment);
#endif

    // Start crash handler
    CrashpadClient *client = new CrashpadClient();
    bool status = client->StartHandler(handler, reportsDir, metricsDir, url.toStdString(), annotations.toStdMap(), arguments, true, true, attachments);
    return status;
}

Be sure to update the values for dbName, appName and appVersion to values specific to your application. The Paths class allows you to get platform-specific paths for Crashpad; its source can be found here. To configure the paths to crashpad_handler, metricsDir, reportsDir and attachment you'll first want to find the location of your executable using the sample code below:

#if defined(Q_OS_WIN)
    #define NOMINMAX
    #include <windows.h>
#endif

#if defined(Q_OS_MAC)
    #include <mach-o/dyld.h>
#endif

#if defined(Q_OS_LINUX)
    #include <unistd.h>
    #define MIN(x, y) (((x) < (y)) ? (x) : (y))
#endif

QString getExecutableDir() {
#if defined(Q_OS_MAC)
    unsigned int bufferSize = 512;
    std::vector<char> buffer(bufferSize + 1);

    if(_NSGetExecutablePath(&buffer[0], &bufferSize))
    {
        buffer.resize(bufferSize);
        _NSGetExecutablePath(&buffer[0], &bufferSize);
    }

    char* lastForwardSlash = strrchr(&buffer[0], '/');
    if (lastForwardSlash == NULL) return NULL;
    *lastForwardSlash = 0;

    return &buffer[0];
#elif defined(Q_OS_WINDOWS)
    HMODULE hModule = GetModuleHandleW(NULL);
    WCHAR path[MAX_PATH];
    DWORD retVal = GetModuleFileNameW(hModule, path, MAX_PATH);
    if (retVal == 0) return NULL;

    wchar_t *lastBackslash = wcsrchr(path, '\\');
    if (lastBackslash == NULL) return NULL;
    *lastBackslash = 0;

    return QString::fromWCharArray(path);
#elif defined(Q_OS_LINUX)
    char pBuf[FILENAME_MAX];
    int len = sizeof(pBuf);
    int bytes = MIN(readlink("/proc/self/exe", pBuf, len), len - 1);
    if (bytes >= 0) {
        pBuf[bytes] = '\0';
    }

    char* lastForwardSlash = strrchr(&pBuf[0], '/');
    if (lastForwardSlash == NULL) return NULL;
    *lastForwardSlash = '\0';

    return QString::fromStdString(pBuf);
#else
    #error getExecutableDir not implemented on this platform
#endif
}

Add a call to initializeCrashpad at your application's entry point.

int main(int argc, char *argv[]) {
    QString dbName = "Fred";
    QString appName = "myQtCrasher";
    QString appVersion = "1.0";
    initializeCrashpad(dbName, appName, appVersion);
}

Symbols

You can download the platform-specific symbol-upload executables on the GitHub releases page.

To get function names and line numbers in your crash reports, you will need to generate and upload .sym files to BugSplat. Crashpad .sym files can be generated from a macOS .dSYM file, a Windows .pdb file or a Linux .debug file.

To generate .dSYM, .pdb and .debug files add the following to the project file:

# Create symbols for dump_syms and symupload
CONFIG += force_debug_info
CONFIG += separate_debug_info

BugSplat's symbol-upload executable can generate .sym files as part of the symbol upload process. To generate .sym files from your .dSYM, .pdb, and .debug files, invoke symbol-upload with the -m flag as demonstrated in the platform-specific examples below.

macOS

If you downloaded symbol-upload-macos via a web browser, you will need to right-click and open the file before you can run the symbol-upload command.

To generate and upload .sym files as part of your build, create a symbols.sh script that calls symbol-upload-macos:

symbol_upload="${1}/Crashpad/Tools/MacOS/symbol-upload-macos"
database="${3}"
app="${4}"
version="${5}"
dir="${2}"
file="${4}.app.dSYM"
user="${6}"
password="${7}"

eval "${symbol_upload} -b ${database} -a \"${app}\" -v \"${version}\" -d \"${dir}\" -f \"${file}\" -u \"${user}\" -p \"${password}\" -m"

Call symbols.sh from your QMAKE_POST_LINK step:

# Crashpad rules for MacOS
macx {
    ...
    # Copy crashpad_handler, attachment.txt to build directory, and upload symbols
    QMAKE_POST_LINK += "mkdir -p $$OUT_PWD/crashpad"
    QMAKE_POST_LINK += "&& cp $$PWD/Crashpad/Bin/MacOS/crashpad_handler $$OUT_PWD/crashpad"
    QMAKE_POST_LINK += "&& bash $$PWD/Crashpad/Tools/MacOS/symbols.sh $$PWD $$OUT_PWD $$BUGSPLAT_DATABASE $$BUGSPLAT_APPLICATION $$BUGSPLAT_VERSION $$BUGSPLAT_USER $$BUGSPLAT_PASSWORD"
}

After each build, you must re-upload symbol files. For best results, you should increment the version number each time you release your application. The dbName, appName, and appVersion values from the Configuring Crashpad section must match the values set for $$BUGSPLAT_DATABASE, $$BUGSPLAT_APPLICATION , and $$BUGSPLAT_VERSION.

Windows

To generate and upload .sym files as part of your build, create a symbols.sh script that calls symbol-upload-windows.exe:

%1\Crashpad\Tools\Windows\symbol-upload-windows.exe -b %3 -a "%4" -v "%5" -d "%2" -f "%4.exe" -u "%6" -p "%7" -m

Call symbols.bat from your QMAKE_POST_LINK step:

# Crashpad rules for Windows
win32 {
    ...
    # Copy crashpad_handler, attachment.txt to build directory, and upload symbols
    QMAKE_POST_LINK += "mkdir $$shell_path($$OUT_PWD)\crashpad"
    QMAKE_POST_LINK += "& copy /y $$shell_path($$PWD)\Crashpad\Bin\Windows\crashpad_handler.exe $$shell_path($$OUT_PWD)\crashpad\crashpad_handler.exe"
    QMAKE_POST_LINK += "&& $$shell_path($$PWD)\Crashpad\Tools\Windows\symbols.bat $$shell_path($$PWD) $$shell_path($$EXEDIR) $$BUGSPLAT_DATABASE $$BUGSPLAT_APPLICATION $$BUGSPLAT_VERSION $$BUGSPLAT_USER $$BUGSPLAT_PASSWORD"
    QMAKE_POST_LINK += "&& copy /y $$shell_path($$PWD)\Crashpad\attachment.txt $$shell_path($$OUT_PWD)\attachment.txt"
}

Linux

To generate and upload .sym files as part of your build, create a symbols.sh script that calls symbol-upload-macos:

#!/bin/bash
symbol_upload="${1}/Crashpad/Tools/Linux/symbol-upload-linux"
database="${3}"
app="${4}"
version="${5}"
dir="${2}"
file="${4}.debug"
user="${6}"
password="${7}"

eval "${symbol_upload} -b ${database} -a \"${app}\" -v \"${version}\" -d \"${dir}\" -f \"${file}\" -u \"${user}\" -p \"${password}\" -m"

Call symbols.sh from your QMAKE_POST_LINK step:

# Crashpad rules for Linux
linux {
    ...
    # Copy crashpad_handler, attachment.txt to build directory, and upload symbols
    QMAKE_POST_LINK += "mkdir -p $$OUT_PWD/crashpad && cp $$PWD/Crashpad/Bin/Linux/crashpad_handler $$OUT_PWD/crashpad/crashpad_handler"
    QMAKE_POST_LINK += "&& $$PWD/Crashpad/Tools/Linux/symbols.sh $$PWD $$OUT_PWD $$BUGSPLAT_DATABASE $$BUGSPLAT_APPLICATION $$BUGSPLAT_VERSION $$BUGSPLAT_USER $$BUGSPLAT_PASSWORD"
    QMAKE_POST_LINK += "&& cp $$PWD/Crashpad/attachment.txt $$OUT_PWD/attachment.txt"
}

Generating a Crash Report

Force a crash in your application after Crashpad has been initialized:

*(volatile int *)0 = 0;

After you've submitted a crash report, navigate to the Dashboard page. Click the link in the ID column to see the details of your crash report. The following image is from our sample myQtCrasher application:

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