Commit f744a069 authored by Bernard van Gastel's avatar Bernard van Gastel
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Added README.

parent f709d3ec
# crashy
C++ crash reporting library for UNIX systems (macOS/Linux/FreeBSD)
C++ crash reporting library for UNIX systems (macOS/Linux/FreeBSD), in Sentry format or plain text. It works by forking a crash reporting process early on, so that all the loaded libraries and locations (which can be different with ASLR) are known. When a crash occurs the main process will report to the crash reporting process the memory locations of the stack trace, breadcrumbs (log messages), and context (thread/actor name). The crash reporting process will take care of resolving the memory locations of the stack trace to function names and file names. This crash reporting process will also take care of sending the crash report (e.g. to Sentry).
## Getting started
To make it easy for you to get started with GitLab, here's a list of recommended next steps.
On Linux+FreeBSD crashy depends on the `dwarf` library to resolve memory locations to symbols. On macOS, the `/usr/bin/atos` utility is used for this (due to the dSYM way of working on macOS).
Already a pro? Just edit this README.md and make it your own. Want to make it easy? [Use the template at the bottom](#editing-this-readme)!
Type of crashes:
- unhandled exceptions;
- segmentation faults and bus errors (incl null pointers);
- assertions:
- debug build only: use `EXPECT(...)`;
- debug and release: use `ENSURE(...)`.
## Add your files
- [ ] [Create](https://docs.gitlab.com/ee/user/project/repository/web_editor.html#create-a-file) or [upload](https://docs.gitlab.com/ee/user/project/repository/web_editor.html#upload-a-file) files
- [ ] [Add files using the command line](https://docs.gitlab.com/ee/gitlab-basics/add-file.html#add-a-file-using-the-command-line) or push an existing Git repository with the following command:
## Getting started
Include this repo as a git submodule in your source tree. In your `CMakeLists.txt` include this subdirectory with:
```
cd existing_repo
git remote add origin https://gitlab.science.ru.nl/ilab/crashy.git
git branch -M main
git push -uf origin main
add_subdirectory(crashy)
```
## Integrate with your tools
- [ ] [Set up project integrations](https://gitlab.science.ru.nl/ilab/crashy/-/settings/integrations)
## Collaborate with your team
- [ ] [Invite team members and collaborators](https://docs.gitlab.com/ee/user/project/members/)
- [ ] [Create a new merge request](https://docs.gitlab.com/ee/user/project/merge_requests/creating_merge_requests.html)
- [ ] [Automatically close issues from merge requests](https://docs.gitlab.com/ee/user/project/issues/managing_issues.html#closing-issues-automatically)
- [ ] [Enable merge request approvals](https://docs.gitlab.com/ee/user/project/merge_requests/approvals/)
- [ ] [Automatically merge when pipeline succeeds](https://docs.gitlab.com/ee/user/project/merge_requests/merge_when_pipeline_succeeds.html)
## Test and Deploy
Use the built-in continuous integration in GitLab.
- [ ] [Get started with GitLab CI/CD](https://docs.gitlab.com/ee/ci/quick_start/index.html)
- [ ] [Analyze your code for known vulnerabilities with Static Application Security Testing(SAST)](https://docs.gitlab.com/ee/user/application_security/sast/)
- [ ] [Deploy to Kubernetes, Amazon EC2, or Amazon ECS using Auto Deploy](https://docs.gitlab.com/ee/topics/autodevops/requirements.html)
- [ ] [Use pull-based deployments for improved Kubernetes management](https://docs.gitlab.com/ee/user/clusters/agent/)
- [ ] [Set up protected environments](https://docs.gitlab.com/ee/ci/environments/protected_environments.html)
***
# Editing this README
When you're ready to make this README your own, just edit this file and use the handy template below (or feel free to structure it however you want - this is just a starting point!). Thank you to [makeareadme.com](https://www.makeareadme.com/) for this template.
## Suggestions for a good README
Every project is different, so consider which of these sections apply to yours. The sections used in the template are suggestions for most open source projects. Also keep in mind that while a README can be too long and detailed, too long is better than too short. If you think your README is too long, consider utilizing another form of documentation rather than cutting out information.
## Name
Choose a self-explaining name for your project.
## Description
Let people know what your project can do specifically. Provide context and add a link to any reference visitors might be unfamiliar with. A list of Features or a Background subsection can also be added here. If there are alternatives to your project, this is a good place to list differentiating factors.
## Badges
On some READMEs, you may see small images that convey metadata, such as whether or not all the tests are passing for the project. You can use Shields to add some to your README. Many services also have instructions for adding a badge.
## Visuals
Depending on what you are making, it can be a good idea to include screenshots or even a video (you'll frequently see GIFs rather than actual videos). Tools like ttygif can help, but check out Asciinema for a more sophisticated method.
## Installation
Within a particular ecosystem, there may be a common way of installing things, such as using Yarn, NuGet, or Homebrew. However, consider the possibility that whoever is reading your README is a novice and would like more guidance. Listing specific steps helps remove ambiguity and gets people to using your project as quickly as possible. If it only runs in a specific context like a particular programming language version or operating system or has dependencies that have to be installed manually, also add a Requirements subsection.
## Usage
Use examples liberally, and show the expected output if you can. It's helpful to have inline the smallest example of usage that you can demonstrate, while providing links to more sophisticated examples if they are too long to reasonably include in the README.
## Support
Tell people where they can go to for help. It can be any combination of an issue tracker, a chat room, an email address, etc.
## Roadmap
If you have ideas for releases in the future, it is a good idea to list them in the README.
## Contributing
State if you are open to contributions and what your requirements are for accepting them.
In your library or executable link with crashy using:
```
target_link_libraries(${PROJECT_NAME} PUBLIC crashy)
```
For people who want to make changes to your project, it's helpful to have some documentation on how to get started. Perhaps there is a script that they should run or some environment variables that they need to set. Make these steps explicit. These instructions could also be useful to your future self.
In your `main()` function, add this code:
```c++
#include "crashy.h"
int main(int argc, char** argv) {
// Builder-like options
CrashOptions options;
// Which format does the sender callback expect
options.sendFormat = CrashOptions::JSON_SENTRY;
// The callback handling the crash report, executed in the crash reporting process (that is forked)
options.sender = [](CrashOptions::SendFormat format, const std::string& payload) -> bool{
if (format == CrashOptions::JSON_SENTRY) {
std::string auth = "auth";
std::string url = "url";
std::stringstream commandBuilder;
commandBuilder << "curl --silent --data " << std::quoted(payload) << " -H \"Content-Type: application/json\" -H " << std::quoted("X-Sentry-Auth: Sentry sentry_version=7, sentry_key=" + auth + ", sentry_client=indigo_crash/0.1") << " " << std::quoted(url);
std::string command = commandBuilder.str();
std::cerr << command << std::endl;
return system(command.c_str()) == 0;
}
std::cerr << payload << std::endl;
return true;
};
// Commandline options can be reported too
options.setCommandLineOptions(argc, argv);
// Callback that can be used to report a context: actor or thread name
options.getContext = []{ return "my-context"; };
// Callback that retrieves the latest log messages for the current context
// In this example we just generate bunch of log messages
options.getBreadcrumbs = [i = 0]() mutable -> std::optional<std::tuple<const char*, time_t, const char*, size_t>> {
if (i == 0) {
++i;
const char* text = "breadcrumb 0";
return {{"error", 42, text, strlen(text)}};
}
if (i == 1) {
++i;
const char* text = "breadcrumb 1";
return {{"info", 37, text, strlen(text)}};
}
return {};
};
// For custom exceptions we need to be able to convert those to a string,
// so we need to provide a callback for this.
options.convertExceptionPtr = [](std::exception_ptr e) -> std::string {
try {
std::rethrow_exception(e);
} catch (uint32_t n) {
return std::string("number: ") + std::to_string(n);
}
};
// initiate the crash reporting service (forking a child process)
GenerateDumpOnCrash(std::move(options));
...
}
```
You can also document commands to lint the code or run tests. These steps help to ensure high code quality and reduce the likelihood that the changes inadvertently break something. Having instructions for running tests is especially helpful if it requires external setup, such as starting a Selenium server for testing in a browser.
# Example program
## Authors and acknowledgment
Show your appreciation to those who have contributed to the project.
If building this project, a `crashtester` binary is build. It demonstrates a couple of behaviours:
- `./crashtester` will trigger a null pointer dereference (because of the `atoi(argv[1])`);
- `./crashtester 0` will be a nop;
- `./crashtester 1` will access memory location 42, and trigger a segfault;
- `./crashtester 2` will throw exception `uint32_t(42)`, and show custom exception handling;
- `./crashtester 3` will show assertion handling with `ENSURE(...)`.
## License
For open source projects, say how it is licensed.
# Limitations
## Project status
If you have run out of energy or time for your project, put a note at the top of the README saying that development has slowed down or stopped completely. Someone may choose to fork your project or volunteer to step in as a maintainer or owner, allowing your project to keep going. You can also make an explicit request for maintainers.
Some inline functions are not correctly reported on Linux+FreeBSD, as they are stored differently in the DWARF format. Arm32 targets are not extensively tested, and there are some indications that sometimes filenames and linenumbers are missing (arm64 appears to work fine).
......@@ -54,7 +54,7 @@
#define _GNU_SOURCE // linux needs this for Dl_info
#endif
#include "crash.h"
#include "crashy.h"
#include <dlfcn.h>
......
#include "crash.h"
#include "crashy.h"
void GenerateDumpOnCrash(CrashOptions&& options [[maybe_unused]]) {
}
......
#include <sys/types.h>
#include <unistd.h>
#include "crash.h"
#include "crashy.h"
// returns a file descriptor to write in binary form a crash report
// and returns a process id of the crash reporter that will finish if it has sent out the crash report
......
#include "crash.h"
#include "crashy.h"
#include <errno.h>
#include <string.h>
......@@ -78,6 +78,7 @@ int main(int argc, char** argv) {
}
};
GenerateDumpOnCrash(std::move(options));
// no arguments will trigger a null pointer here
x = atoi(argv[1]);
if (x != 0)
foo();
......
......@@ -19,7 +19,7 @@
#include <cxxabi.h>
#include "tosourcecode.h"
#include "term-defines.h"
#include "crash.h"
#include "crashy.h"
const char* BaseName(const char *str) {
const char *p = strrchr(str, '/');
......
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