Documentation
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Overview ¶
Package process provides subprocess execution primitives.
This extension is NOT included in the Console profile. Embedders must opt in explicitly with WithExtension(process.Extension) or use WithProfile(KitchenSink).
Spawning asks two KINDS of question, and both must be answered before a child runs.
The CAPABILITY question is security.ResourceProcess with the command as target: ActionExec for process-spawn (structured, no shell), ActionExecShell for system (shell command string). It asks whether this program may spawn a subprocess at all.
The OBJECT questions are security.ResourceFile with ActionExec — the chmod x bit — asked twice: once on the binary that will actually run, and once on the directory the child will start in (POSIX x on a directory is traverse). They ask which binary, from where. Without them a path-confining authorizer never sees either: the capability request carries a command STRING, and /bin/sh is a general-purpose unconfined file accessor that no root ever bounded.
Two details the gates depend on, both in prim_process.go:
- The gated binary is cmd.Path AFTER exec.Command's LookPath resolution, not the caller's string, joined against cmd.Dir when relative — otherwise the authorized file and the executed file can differ.
- The child's start directory is the authorizer's ConfinementRoot when it reports one, not the host's inherited working directory.
Shell Execution ¶
- system
Structured Process Control ¶
- process-spawn, process-wait, process-kill
- process-stdout, process-stderr, process-stdin
Process Predicates ¶
- process?
Use Extension or AddToRegistry to register all primitives.
Index ¶
Constants ¶
This section is empty.
Variables ¶
var AddToRegistry = Builder.AddToRegistry
AddToRegistry registers all process primitives.
var Builder = registry.NewRegistryBuilder(addPrimitives)
Builder aggregates all process registration functions.
var Extension = registry.NewDescribedExtension("process", "OS processes: shell command execution, subprocess spawn/wait/kill with piped stdio.", AddToRegistry)
Extension is the process execution extension.
var PrimProcessStderr = helpers.MakeUnaryAccessor(werr.ErrNotAProcess, "process-stderr", func(proc *values.Process) values.Value {
return proc.Stderr()
})
PrimProcessStderr implements the (process-stderr) primitive.
var PrimProcessStdin = helpers.MakeUnaryAccessor(werr.ErrNotAProcess, "process-stdin", func(proc *values.Process) values.Value {
return proc.Stdin()
})
PrimProcessStdin implements the (process-stdin) primitive.
var PrimProcessStdout = helpers.MakeUnaryAccessor(werr.ErrNotAProcess, "process-stdout", func(proc *values.Process) values.Value {
return proc.Stdout()
})
PrimProcessStdout implements the (process-stdout) primitive.
Functions ¶
func PrimProcessKill ¶
func PrimProcessKill(mc machine.CallContext) error
PrimProcessKill implements the (process-kill) primitive. Sends a signal to the process. Signal is a symbol: term, kill, int, hup.
func PrimProcessQ ¶
func PrimProcessQ(mc machine.CallContext) error
PrimProcessQ implements the (process?) predicate.
func PrimProcessSpawn ¶
func PrimProcessSpawn(mc machine.CallContext) error
PrimProcessSpawn implements the (process-spawn) primitive. Creates a subprocess with stdin/stdout/stderr pipes.
A spawned child is recorded against the calling engine's namespace so Engine.Close can kill and reap it (close.go). A spawn that failed is not recorded.
func PrimProcessWait ¶
func PrimProcessWait(mc machine.CallContext) error
PrimProcessWait implements the (process-wait) primitive. Blocks until the process exits and returns the exit code.
The wait goes through values.Process.Wait, not cmd.Wait: two SRFI-18 threads in (process-wait p), or one of them racing Engine.Close's reaper, would otherwise wait4 the same pid twice and tear cmd.ProcessState between them.
func PrimSystem ¶
func PrimSystem(mc machine.CallContext) error
PrimSystem implements the (system) primitive. Runs a shell command via /bin/sh -c and returns the exit code.
Types ¶
This section is empty.
Source Files