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https://github.com/msantos/prx
an Erlang library for interacting with Unix processes
https://github.com/msantos/prx
capsicum exec fork linux-namespaces pledge prctl procctl seccomp signal supervisor system-programming
Last synced: about 1 month ago
JSON representation
an Erlang library for interacting with Unix processes
- Host: GitHub
- URL: https://github.com/msantos/prx
- Owner: msantos
- License: isc
- Created: 2015-10-04T12:59:37.000Z (over 8 years ago)
- Default Branch: master
- Last Pushed: 2023-11-10T12:19:19.000Z (8 months ago)
- Last Synced: 2024-05-14T05:02:58.850Z (about 2 months ago)
- Topics: capsicum, exec, fork, linux-namespaces, pledge, prctl, procctl, seccomp, signal, supervisor, system-programming
- Language: Erlang
- Size: 604 KB
- Stars: 36
- Watchers: 5
- Forks: 6
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Lists
- awesome-pledge - prx - *an Erlang library for interacting with Unix processes* (Libraries)
README
# prx
[](https://hex.pm/packages/prx)
[](https://hexdocs.pm/prx/)
An Erlang library for Unix process management and system programming
tasks.
prx provides:
* a safe, beam-friendly interface to system calls and other POSIX operations
* simple, reliable OS process management by mapping Erlang processes to
a hierarchy of system processes
* an interface for privilege separation operations to restrict processes
* operations to isolate processes like containers and jails
## Build
```
$ rebar3 compile
```
## Quick Start
`prx` has two basic operations: fork and exec.
```
% Spawn a new system process
{ok, Task} = prx:fork(),
% And a child of the process
{ok, Child} = prx:fork(Task).
```
After fork()'ing, other calls can be made. For example:
```
UID = prx:getuid(Task),
PID = prx:getpid(Child).
```
Calling exec() causes the process I/O to be treated as streams of data:
```
ok = prx:execvp(Child, ["/bin/cat", "-n"]),
prx:stdin(Child, "test\n"),
receive
{stdout,Child,Stdout} ->
Stdout
end.
```
## Usage
* fork and exec /bin/cat
```
{ok, Task} = prx:fork(),
ok = prx:execvp(Task, ["/bin/cat", "-n"],
prx:stdin(Task, "test\n"),
receive {stdout, Task, _} = Out -> Out end.
```
* creating a pipeline of child processes
prx processes can fork child prx processes:
```
beam
|-erl_child_setup
| `-prx
| `-prx
```
After calling exec, the process tree looks like:
```
beam
|-erl_child_setup
| `-prx
| `-cat
```
```
{ok, Task} = prx:fork(),
{ok, Child} = prx:fork(Task),
OSPid = prx:getpid(Child),
ok = prx:execvp(Child, ["/bin/cat", "-n"],
prx:stdin(Child, "test\n"),
receive {stdout, Child, _} = Out -> Out end.
```
* running `cat` within a containerized namespace
```
application:set_env(prx, options, [{exec, "sudo -n"}]),
{ok, Task} = prx:fork(),
{ok, Child} = prx:clone(Task, [clone_newnet, clone_newpid, clone_newipc,
clone_newuts, clone_newns]),
OSPid = prx:getpid(Child),
ok = prx:execvp(Child, ["/bin/cat", "-n"],
prx:stdin(Child, "test\n"),
receive {stdout, Child, _} = Out -> Out end.
```
## Documentation
https://hexdocs.pm/prx/
See also: [alcove](https://hexdocs.pm/alcove/)