Add binpatch module to bashkit

modules/bashbinpatch.bash

@@ -0,0 +1,147 @@
+#!/usr/bin/env bash
+# bashbinpatch.bash --
+# bashkit module
+# ----
+# (ɔ) 2022 wuage.org
+
+# shellcheck source-path=SCRIPTDIR
+# shellcheck enable=require-variable-braces,check-set-e-suppressed
+
+
+if [[ $0 = "${BASH_SOURCE[0]}" ]]; then
+    printf '%s is to be sourced not executed!\n' "${BASH_SOURCE[0]}"
+    exit 1
+fi
+
+if ! declare -p BASHKIT &> /dev/null; then
+    printf 'try source bashkit.bash\n'
+    exit 1
+fi
+
+bashbinpatch__is_and_and() {
+    __connector_test() {
+        false
+        true
+    }
+    if __connector_test; then
+        unset -f __connector_test
+        return 1
+    fi
+    unset -f __connector_test
+    return 0
+}
+
+bashbinpatch::handler() {
+    cmd=${1:-status}
+
+    case ${cmd} in
+        enable)
+            # command connector is already and_and
+            if bashbinpatch__is_and_and; then
+                return 0
+            fi
+            warn '/!\ binpatching is dirty, and might not work with all bash versions'
+            shift
+            bashbinpatch__patch "$@"
+            ;;
+        disable)
+            warn '!!! disabling bashbinpatch handler is not advised !!!'
+            debug 'disabling bashbinpatch handler may result in non obvious bad script side effects'
+            if bashbinpatch__is_and_and; then
+                error "cannot disable bashbinpatch, it is builtin into bash binary (${BASH})"
+                return 1
+            fi
+            ;;
+        status)
+            if bashbinpatch__is_and_and; then
+                return 0
+            fi
+            return 1
+            ;;
+        *)
+            fatal 'bad command'
+            ;;
+    esac
+}
+
+bashbinpatch__patch() {
+    local dir="${BASHBINPATCH_DIR:-${XDG_RUNTIME_DIR:-${TMPDIR:-${HOME:-.}}}}/.bashbinpatch"
+    local bashand="${dir}/bash"
+
+    if (("${BASH_VERSINFO[0]}" < 5 )) \
+    && { (("${BASH_VERSINFO[0]}" < 4 )) && (("${BASH_VERSINFO[1]}" < 1 )); }; then
+        raise "Minimum supported bash version is 4.1" \
+        || fatal
+    fi
+    if (("${BASH_VERSINFO[0]}" > 4 )) && (("${BASH_VERSINFO[1]}" > 2 )); then
+        raise "Maximum supported bash version is 5.2" \
+        || fatal
+    fi
+
+    if [[ "${BASH_ARGV0##*/}" == "bash" ]]; then
+        # ARGV0 is bash probably called with bash -c
+        raise "bash -c, no dynamic bashand" || return ${?}
+    fi
+
+    bashkit::load check
+
+    check::cmd xxd tr sed grep wc
+    check::dir "${dir}"
+
+    if ! [[ -f "${bashand}" ]]; then
+        local pos=2 # Bash < 5.2
+        if (("${BASH_VERSINFO[0]}" > 4 )) && (("${BASH_VERSINFO[1]}" > 1 )); then
+            pos=3
+        fi
+        case "${HOSTTYPE}" in
+            x86_64)
+                local linecount
+                read -r linecount < <( xxd -p -c 0 "${BASH}" | tr -d '[:space:]' | grep -o 'ba3b000000' | wc -l )
+                case ${linecount} in
+                    2|3) : ;;
+                    *) raise "unexpected line count (${linecount})" || return $? ;;
+                esac
+                xxd -p -c 0 "${BASH}" \
+                    | tr -d '[:space:]' \
+                    | sed "s|ba3b000000|ba20010000|${pos}" \
+                    | xxd -r -p > "${bashand}"
+            ;;
+            i386|i686)
+                # i386 use a 2byte instruction to push ';'(0x3b)
+                # making it hard to patch to '&&'(0x120)
+                raise "${HOSTTYPE} unimplemented!" || return $?
+            ;;
+            aarch64)
+                local linecount
+                read -r linecount < <( xxd -p -c 0 "${BASH}" | tr -d '[:space:]' | grep -o '62078052' | wc -l )
+                case ${linecount} in
+                    1) pos=1 ;;
+                    3) : ;;
+                    *) raise "unexpected line count (${linecount})" || return $? ;;
+                esac
+                xxd -p -c 0 "${BASH}" \
+                    | tr -d '[:space:]' \
+                    | sed "s|62078052|02248052|${pos}" \
+                    | xxd -r -p > "${bashand}"
+            ;;
+            arm*)
+                local linecount
+                read -r linecount < <( xxd -p -c 0 "${BASH}" | tr -d '[:space:]' | grep -o '3b20a0e3' | wc -l )
+                case ${linecount} in
+                    2) : ;;
+                    *) raise "unexpected line count (${linecount})" || return $? ;;
+                esac
+                xxd -p -c 0 "${BASH}" \
+                    | tr -d '[:space:]' \
+                    | sed "s|3b20a0e3|122ea0e3|${pos}" \
+                    | xxd -r -p > "${bashand}"
+            ;;
+            *) raise "${HOSTTYPE} unimplemented!" || return $? ;;
+        esac
+    fi
+    # fix perms
+    chmod 700 "${dir}"
+    chmod 500 "${bashand}"
+    export PATH="${dir}:${PATH}"
+    exec "${bashand}" "${BASH_ARGV0}" "$@"
+}

test/bashkit/modules/bashbinpatch/binpatch.bats

@@ -0,0 +1,86 @@
+#!/usr/bin/env bats
+# wuage bash script devkit test suite
+# ----
+# (ɔ) 2022 wuage.org
+
+# shellcheck disable=SC2016  # allow expression in single quotes
+
+load "${BATS_TEST_DIRNAME%test*}/test/helper/common-setup"
+
+is_binpatch_compatible() {
+    if (("${BASH_VERSINFO[0]}" < 5 )) \
+    && { (("${BASH_VERSINFO[0]}" < 4 )) && (("${BASH_VERSINFO[1]}" < 1 )); }; then
+        return 1
+    fi
+    if (("${BASH_VERSINFO[0]}" > 4 )) && (("${BASH_VERSINFO[1]}" > 2 )); then
+        return 1
+    fi
+    return 0
+}
+
+@test "bashbinpatch do nothing if already bashand" {
+    is_bashand || skip 'need bashand';
+
+    run -0 bash -c '
+    source bashkit.bash bashbinpatch
+    bashbinpatch::handler
+    '
+    assert_output ''
+}
+
+@test "binpatch doesn't work with bash -c" {
+    is_bashand && skip 'need bash';
+    is_binpatch_compatible || skip 'need compatible bash';
+
+    # shellcheck disable=SC2031,SC2030 # BASHBINPATCH_DIR is set for test
+    export BASHBINPATCH_DIR="${BATS_TEST_TMPDIR}"
+
+    run -1 bash -c '
+    source bashkit.bash bashbinpatch
+    warn() { :; } # remove warning
+    bashbinpatch::handler enable || error
+    '
+    assert_log 'error' 'bashbinpatch__patch' 'bash -c, no dynamic bashand'
+}
+
+@test "binpatch fails on unimplemented hosttype" {
+    is_bashand && skip 'need bash';
+    is_binpatch_compatible || skip 'need compatible bash';
+
+    # shellcheck disable=SC2031,SC2030 # BASHBINPATCH_DIR is set for test
+    export BASHBINPATCH_DIR="${BATS_TEST_TMPDIR}"
+
+    printf '%s\n'                           \
+        "#!/bin/env bash"                   \
+        "HOSTTYPE='unimplemented'"          \
+        "source bashkit.bash bashbinpatch"  \
+        "bashbinpatch::handler enable || error" \
+    > "${BATS_TEST_TMPDIR}/script.bash"
+
+    run -1 bash "${BATS_TEST_TMPDIR}/script.bash"
+
+    assert_log 'error' 'bashbinpatch__patch' 'unimplemented unimplemented!'
+}
+
+@test "binpatch call the script again, bashand keeps arguments" {
+    is_bashand && skip 'need bash';
+    is_binpatch_compatible || skip 'need compatible bash';
+
+    # shellcheck disable=SC2031,SC2030 # BASHBINPATCH_DIR is set for test
+    export BASHBINPATCH_DIR="${BATS_TEST_TMPDIR}"
+
+    printf '%s\n'                                         \
+        "#!/bin/env bash"                                 \
+        "source bashkit.bash check bashbinpatch"          \
+        "bashbinpatch::handler enable \"\$@\" || fatal"   \
+        "f() {"                                           \
+        "   false"                                        \
+        "   true"                                         \
+        "}"                                               \
+        "f || echo \"\$@\""                               \
+    > "${BATS_TEST_TMPDIR}/script.bash"
+
+    run -0 timeout 2s bash "${BATS_TEST_TMPDIR}/script.bash" bashand is cool
+    assert_log 'warn' 'bashbinpatch::handler' '... binpatching is dirty, and might not work with all bash versions'
+    assert_output -p 'bashand is cool'
+}