Structural Context

The core innovation of ccchain is structural context — the ability to write rules that depend on where a command appears in a shell expression, not just what the command is.

Pipes Build Context

When commands are connected by |, each command inherits the context of its parent:

allow find
  |,>>
    deny rm  "don't pipe find into rm"

Command	Context	Result
find .	(top-level)	allow
find . | rm	find → pipe → rm	deny
find . | grep foo	find → pipe → grep	allow (no matching pipe rule)

Chains Reset Context

&&, ||, and ; are reset points. The command after a chain operator is evaluated from scratch at the top level:

deny rm
allow find
  |,>>
    deny rm  "don't pipe find into rm"

Command	Evaluation	Result
find . | rm	find's pipe context → deny rm	deny (pipe rule)
find . && rm foo	reset at && → rm at top level → deny rm	deny (top-level rule)
find . && ls	reset at && → ls at top level	allow

This matches shell execution semantics: && means "run the next command independently if the previous succeeded."

Exec Context

Some commands run other commands as arguments. ccchain detects these patterns and evaluates the nested command in an exec: context:

allow find
  exec:
    deny rm  "expand to tempfile first"
    allow cp, mv

Command	Detection	Result
find . -exec rm {} \;	-exec triggers exec context	deny
find . -exec cp {} /tmp/ \;	-exec triggers exec context	allow

Supported Nest Patterns

Pattern	Detection
find -exec CMD {} \;	-exec / -execdir argument
xargs CMD	First non-flag argument
bash -c "CMD"	-c argument (recursively parsed)
sh -c "CMD"	-c argument (recursively parsed)
eval "CMD"	Argument (static strings only)

Unanalyzable Commands

Commands that involve dynamic expansion cannot be statically analyzed:

$cmd foo              # variable as command name
$(generate_cmd) foo   # command substitution as command name
eval "$dynamic"       # dynamic eval argument

These are automatically denied with a message explaining why:

{
  "action": "deny",
  "message": "dynamic command detected: static analysis not possible"
}