48 lines
1.8 KiB
Markdown
48 lines
1.8 KiB
Markdown
# clone-shim
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## Running the examples
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### examples/fib
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The fib example performs fibonacci trivially on a fixed number. It is the most basic example of a process that requires no privilege, excluding `Stdout` to print the result.
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To run this example:
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cargo build
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cargo build --example fib
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target/debug/clone-shim -s examples/fib/spec.json target/debug/examples/fib
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### examples/basic
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The basic example instructs the shim to spawn two processes, each of which writes "hello from main{1,2}!" to stdout.
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To run this example:
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cargo build
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cargo build --example basic
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target/debug/clone-shim -s examples/basic/spec.json target/debug/examples/basic
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### examples/pipes
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The pipes example shows some of the power of the shim by using pipes. The process "pipe_sender" sends two messages down a pipe that it's given by the shim. These two messages each spawn a completely isolated process, "pipe_receiver", that receives that message.
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To run this example:
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cargo build
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cargo build --example pipes
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target/debug/clone-shim -s examples/pipes/spec.json target/debug/examples/pipes
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## Debugging the shim
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The shim can be debugged as with most processes, but it is exceptionally forky. Breaking before a clone in `rust-gdb` then running `set follow-fork-mode child` is often necessary. The best approach is to go in with a plan of attack.
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## Debugging the child
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Debugging the child processes is vastly more difficult than in other more Linux-like containerisation solutions.
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The `--debug` flag on the shim attempts to stop application spawned processes as soon as they are voided. This gives you a chance to attach with a debugger.
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The debugger must be run from the ambient namespace and not within the void, as none of the prerequisites will exist within the void.
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Good luck!
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