seth: add function selector and calldata encoding/decoding helpers

src/seth/CHANGELOG.md

@@ -9,6 +9,11 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Changed
 
 - `seth --to-wei` now uses eth instead of wei as the default unit for conversions
+- `seth 4byte` command returns the response from querying [4byte.directory](https://www.4byte.directory/) for a given function signature
+- `seth 4byte-decode` command queries 4byte.directory for matching function signatures, uses one to decode the calldata, and prints the decoded calldata
+- `seth 4byte-event` command returns the response from querying 4byte.directory for a given event topic
+- `seth abi-encode` command returns the ABI encoded values without the function signature
+- `seth index` command returns the slot number for the specified mapping type and input data
 
 ## [0.11.0] - 2021-09-08
 

src/seth/README.md

@@ -69,6 +69,10 @@ hardware wallets—even if you use a remote RPC node like Infura's.
   - [`seth --to-int256`]
   - [`seth --to-uint256`]
   - [`seth --to-wei`]
+  - [`seth 4byte`]
+  - [`seth 4byte-decode`]
+  - [`seth 4byte-event`]
+  - [`seth abi-encode`]
   - [`seth age`]
   - [`seth balance`]
   - [`seth basefee`]
@@ -85,7 +89,7 @@ hardware wallets—even if you use a remote RPC node like Infura's.
   - [`seth etherscan-source`]
   - [`seth events`]
   - [`seth gas-price`]
-  - [`seth help`]
+  - [`seth index`]
   - [`seth keccak`]
   - [`seth logs`]
   - [`seth lookup-address`]
@@ -452,6 +456,46 @@ Convert an ETH amount into wei.
 
 The unit may be `wei`, `gwei`, `eth`, or `ether`.
 
+### `seth 4byte`
+
+Prints the response from querying [4byte.directory](https://www.4byte.directory/) for a given function signature
+
+    seth 4byte <calldata> [<options>]
+
+Any calldata appended after the function signature will be stripped before querying 4byte.directory.
+
+By default, just the signatures will be printed, but the `-v` flag can be used to print the full JSON response.
+
+### `seth 4byte-decode`
+
+Queries [4byte.directory](https://www.4byte.directory/) for matching function signatures, uses one to decode the calldata, and prints the decoded calldata.
+
+    seth 4byte-decode <calldata> [<options>]
+
+By default, the user will be prompted to select a function signature to use for decoding the calldata.
+
+The `--id` flag can be passed to bypass interactive mode.
+Use `--id earliest` or `--id latest` to use the oldest and newest functions in the 4byte.directory database, respectively.
+Use `--id <number>` to select a function signature by it's ID in the 4byte.directory database.
+
+### `seth 4byte-event`
+
+Prints the response from querying [4byte.directory](https://www.4byte.directory/) for a given event topic
+
+    seth 4byte-event <topic> [<options>]
+
+By default, just the signatures will be printed, but the `-v` flag can be used to print the full JSON response.
+
+### `seth abi-encode`
+
+Prints the ABI encoded values without the function signature
+
+    seth abi-encode <sig> [<args>]
+
+ABI encode values based on a provided function signature, slice off the leading the function signature,
+and print the result. It does not matter what the name of the function is, as only the types and values
+affect the output.
+
 ### `seth age`
 
 Show the timestamp of a block (the latest block by default).
@@ -631,6 +675,17 @@ See also [`seth logs`] which does not decode events.
 
 Reads the current gas price at target chain.
 
+### `seth index`
+
+Prints the slot number for the specified mapping type and input data
+
+    seth index <fromtype> <totype> <fromvalue> <slot> [<lang>]
+
+`lang` will default to Solidity when not specified.
+To compute the slot for Vyper instead, specify `v`, `vy`, or `vyper`.
+
+Result is not guaranteed to be accurate for all Vyper versions since the Vyper storage layout is not yet stable.
+
 ### `seth keccak`
 
 Print the Keccak-256 hash of an arbitrary piece of data.
@@ -825,6 +880,10 @@ Show all fields unless `<field>` is given.
 [`seth --calldata-decode`]: #seth---calldata-decode
 [`seth block-number`]: #seth-block-number
 [`seth gas-price`]: #seth-gas-price
+[`seth 4byte`]: #seth-4byte
+[`seth 4byte-decode`]: #seth-4byte-decode
+[`seth 4byte-event`]: #seth-4byte-event
+[`seth abi-encode`]: #seth-abi-encode
 [`seth abi`]: #seth-abi
 [`seth age`]: #seth-age
 [`seth balance`]: #seth-balance
@@ -841,6 +900,7 @@ Show all fields unless `<field>` is given.
 [`seth etherscan-source`]: #seth-etherscan-source
 [`seth events`]: #seth-events
 [`seth help`]: #seth-help
+[`seth index`]: #seth-index
 [`seth keccak`]: #seth-keccak
 [`seth logs`]: #seth-logs
 [`seth lookup-address`]: #seth-lookup-address

src/seth/libexec/seth/seth

@@ -50,6 +50,9 @@
 ###    --source=<file>            path to combined.json source
 ###    --state=<dir>              directory to store hevm state in
 ###
+### Options for seth-4byte-decode(1):
+###
+###    --id                       'earliest' or 'latest' or the ID number of a particular signature
 ###
 ### Other options:
 ###
@@ -106,6 +109,9 @@ no-src               don't fetch contract source
   Options for seth-bundle-source(1):
 D,dir=directory      directory to store output
 
+  Options for seth-4byte-decode(1):
+id=string|number     'earliest' or 'latest' or the ID number of a particular signature
+
   Other options:
 async                do not wait for transaction receipt
 follow               go into a loop watching for new logs
@@ -185,6 +191,7 @@ while [[ $1 ]]; do
        --async)             export SETH_ASYNC=yes;;
        --follow)            export SETH_FOLLOW=yes;;
     -j|--json)              export SETH_JSON=yes;;
+       --id)         shift; export SETH_4BYTE_ID=$1;;
 
     *) printf "${0##*/}: internal error: %q\\n" "$1"; exit 1
   esac; shift

src/seth/libexec/seth/seth-4byte

@@ -0,0 +1,17 @@
+#!/usr/bin/env bash
+### seth-4byte -- prints the response from querying 4byte.directory for a given function signature
+### Usage: seth 4byte <calldata> [<options>]
+###
+### Takes a 4 byte function signature and prints matching functions from 4byte.directory. This will also strip
+### any appended calldata after the first four bytes
+###
+### When the --verbose option is used, the full JSON response is printed, otherwise just text signatures are printed
+
+set -e
+[[ $# -eq 1 ]] || seth --fail-usage "$0"
+
+if [[ $SETH_VERBOSE ]]; then
+  curl -s "https://www.4byte.directory/api/v1/signatures/?hex_signature=${1:0:10}" | jq .
+else
+  curl -s "https://www.4byte.directory/api/v1/signatures/?hex_signature=${1:0:10}" | jq '.results[] | .text_signature' 
+fi

src/seth/libexec/seth/seth-4byte-decode

@@ -0,0 +1,53 @@
+#!/usr/bin/env bash
+### seth-4byte-decode -- querys 4byte.directory to find a matching signature, then decodes the calldata with it
+### Usage: seth 4byte-decode <calldata> [<options>]
+###
+### Querys 4byte.directory to find matching signatures and prompts the user to to select one. The selected
+### signature will be used to decode the calldata.
+
+set -e
+[[ $# -eq 1 ]] || seth --fail-usage "$0"
+
+if [[ -z $SETH_4BYTE_ID ]]; then
+  # Function signature ID not specified, prompt user to choose a signature
+  sigs=$(curl -s "https://www.4byte.directory/api/v1/signatures/?hex_signature=${1:0:10}" | jq '.results[] | .text_signature' )
+  PS3="Select a function signature by number: "
+  select sig in $sigs; do
+    break
+  done
+  echo "" # add a line break for easier reading
+else
+  # Function signature ID was specified, so parse results without user input
+  results=$(curl -s "https://www.4byte.directory/api/v1/signatures/?hex_signature=${1:0:10}" | jq .results[] )
+  sigs=$(echo $results | jq '.text_signature')
+
+  # sigs is a string so split it into an array
+  sigarray=()
+  for sig in $sigs; do sigarray+=($sig); done
+  length=${#sigarray[@]}
+
+  # parse the provided ID
+  if [[ $SETH_4BYTE_ID = earliest ]]; then
+    # first one added to 4byte is the last in the array
+    sig=${sigarray[$length-1]}
+  elif [[ $SETH_4BYTE_ID = latest ]]; then
+     # last one added to 4byte is the first in the array
+     sig=${sigarray[0]}
+  else
+    # specific ID number provided (if using this option, you may be better off with `seth --calldata-decode`)
+    query=". | select(.id==$SETH_4BYTE_ID) | .text_signature"
+    sig=$(echo $results | jq "$query")
+  fi
+fi
+
+# Exit if no sig found
+if [[ -z $sig ]]; then
+  echo >&2 "seth 4byte-decode: no signature found"
+  exit 1
+elif [[ $SETH_VERBOSE ]]; then
+  echo "signature: $sig"
+fi
+
+# Remove leading and trailing quotes from JSON, then decode
+sig="${sig//\"}"
+seth --calldata-decode $sig $1

src/seth/libexec/seth/seth-4byte-event

@@ -0,0 +1,14 @@
+#!/usr/bin/env bash
+### seth-4byte-event -- prints the response from querying 4byte.directory for a given function topic
+### Usage: seth 4byte-event <topic> [<options>]
+###
+### Takes a 32 byte topic and prints the response from querying 4byte.directory for that topic
+
+set -e
+[[ $# -eq 1 ]] || seth --fail-usage "$0"
+
+if [[ $SETH_VERBOSE ]]; then
+  curl -s "https://www.4byte.directory/api/v1/event-signatures/?hex_signature=$1" | jq .
+else
+  curl -s "https://www.4byte.directory/api/v1/event-signatures/?hex_signature=$1" | jq '.results[] | .text_signature' 
+fi

src/seth/libexec/seth/seth-abi-encode

@@ -0,0 +1,12 @@
+#!/usr/bin/env bash
+### seth-abi-encode -- ABI encode values, and prints the encoded values without the function signature
+### Usage: seth abi-encode <sig> [<args>]
+###
+### ABI encode values based on a provided function signature, slice off the leading the function signature,
+### and print the result. It does not matter what the name of the function is, as only the types and values
+### affect the output.
+
+set -e
+
+x=$(seth calldata $@); # generate full calldata based on function signature
+echo "0x${x:10}" # slice off the function signature and only keep the encoded values

src/seth/libexec/seth/seth-index

@@ -0,0 +1,24 @@
+#!/usr/bin/env bash
+### seth-index -- Prints the slot number for the specified mapping type and input data
+### Usage: seth index <fromtype> <totype> <fromvalue> <slot> [<lang>]
+###
+### Prints the slot number for the specified mapping type and input data. For example,
+### the balances mapping in DAI is slot 2, so to find the slot where the balance 
+### is stored for <account>, use
+###     seth-index address uint256 <account> 2
+###
+### `lang` will default to Solidity when not specified. To use Vyper, enter `v`, `vy`,
+### or `vyper`. The above example cna be repeated for a Vyper token with
+###     seth-index address uint256 <account> 2 vyper
+
+set -e
+[[ $# -eq 4 ]] || [[ $# -eq 5 ]] || seth --fail-usage "$0"
+
+if [[ $5 = 'vyper' || $5 = 'vy' || $5 = 'v' ]]; then
+  # note: not guaranteed to be accurate for all Vyper versions since storage layout is not yet stable
+  # more info: https://twitter.com/big_tech_sux/status/1420159854170152963
+  echo >&2 "${0##*/}: warning: not guaranteed to be accurate for all Vyper versions since storage layout is not yet stable"
+  echo $(seth keccak $(seth abi-encode "x($2,$1)" $4 $3));
+else
+  echo $(seth keccak $(seth abi-encode "x($1,$2)" $3 $4));
+fi

src/seth/libexec/seth/seth-sig

@@ -5,5 +5,20 @@
 ### Returns: 0x2e1a7d4d
 set -e
 [[ $# = 1 ]] || seth --fail-usage "$0"
-method=$(seth keccak "$1")
-echo "${method:0:10}"
+
+# Get ABI from input
+abi=$(seth --abi-function-json "$1")
+inputs=$(echo $abi | jq '.inputs[] | .type')
+
+# Generate dummy args
+args=()
+for input in $inputs; do
+  type="${input//\"}" # remove leading and trailing quotes from the JSON
+  end=${type: -2} # get the last two characters to check for array types
+  [ $end = "[]"  ] && arg="[]" || arg=0 # use [] for array types and 0 otherwise
+  args+=(--arg "$arg")
+done
+
+# Use dummy args generate calldata and only keep the function selector
+calldata=$(hevm abiencode --abi "$abi" "${args[@]}")
+echo "${calldata:0:10}"