Module introspect

Expand description

Instruction introspection – stack height and sibling instruction access.

These wrappers support security patterns based on transaction and call-stack introspection:

CPI guard: Detect if the current instruction is running inside a CPI call (stack height > 1). Prevents unauthorized composition – e.g., a governance instruction that must be top-level only.
Ed25519 signature verification: Check that a previous instruction in the same transaction was to the Ed25519 precompile with specific data. This is how on-chain programs verify off-chain signatures without heavy crypto libraries.
Secp256k1 recovery: Same pattern for Ethereum-compatible signatures.

Hopper wraps these syscalls behind small typed helpers so programs do not need to repeat raw unsafe glue at every call site.

Structs§

ProcessedInstruction: Metadata about a previously processed sibling instruction.

ED25519_PROGRAM_ID: Well-known precompile address for Ed25519 signature verification.
SECP256K1_PROGRAM_ID: Well-known precompile address for Secp256k1 signature recovery.
SECP256R1_PROGRAM_ID: Well-known precompile address for Secp256r1 (P-256) signature verification (SIMD-0075). This is the precompile that backs passkey / WebAuthn signature checks on Solana.

get_processed_instruction: Retrieve a previously processed sibling instruction from the current transaction.
get_stack_height: Get the current instruction stack height.
is_cpi: Returns true if the current instruction is running inside a CPI.
is_top_level: Returns true if the current instruction is at the top level (not running inside a CPI).
require_cpi: Require that the current instruction IS inside a CPI.
require_ed25519_instruction: Check that a previous sibling instruction was to the Ed25519 precompile.
require_secp256k1_instruction: Check that a previous sibling instruction was to the Secp256k1 precompile.
require_secp256r1_instruction: Check that a previous sibling instruction was to the Secp256r1 (P-256) precompile, the verification path for passkeys / WebAuthn.
require_top_level: Require that the current instruction is NOT a CPI call.