Merge pull request #175 from mbland/safe-prompt

Add @go.prompt_for_safe_input to lib/prompt

lib/prompt

@@ -9,6 +9,9 @@
 #   @go.prompt_for_input
 #     Prompts the user for a line of input
 #
+#   @go.prompt_for_safe_input
+#     Prompts the user for a line of input, then validates it isn't dangerous
+#
 #   @go.prompt_for_yes_or_no
 #     Prompts the user for a yes or no response
 #
@@ -61,6 +64,42 @@
   fi
 }
 
+# Prompts the user for a line of input, then validates it isn't dangerous
+#
+# With the exception of the `--or-die` option, the arguments are the same as the
+# underlying `@go.prompt_for_input`. Useful if the input value may be used to
+# construct a command or query.
+#
+# Options (must be specified before arguments):
+#   --or-die <desc>  Print description and stack and exit with error if invalid
+#
+# Arguments:
+#   result_var  Name of the caller-declared variable for the result
+#   prompt      Text prompt for user input
+#   default     (Optional) Default value if response is empty
+#   fail_msg    (Optional) Failure message if empty input isn't valid
+@go.prompt_for_safe_input() {
+  local or_die
+  local description
+
+  if [[ "$1" == '--or-die' ]]; then
+    or_die='true'
+    description="$2"
+    shift 2
+  fi
+  @go.validate_identifier_or_die 'Input prompt response variable name' "$1"
+
+  if ! @go.prompt_for_input "$@"; then
+    return 1
+  elif [[ "$or_die" == 'true' ]]; then
+    @go.validate_input_or_die "$description" "${!1}"
+  elif ! @go.validate_input "${!1}"; then
+    @go.printf '"%s" is an invalid response, as it contains %s.\n' \
+      "${!1}" 'unescaped shell metacharacters or control operators' >&2
+    return 1
+  fi
+}
+
 # Prompts the user for a yes or no response
 #
 # Arguments:

lib/validation

@@ -52,8 +52,9 @@ readonly __GO_VALID_IDENTIFIER_PATTERN='^[[:alpha:]_][[:alnum:]_]*$'
   local skip_callers="${3:-2}"
 
   if ! @go.validate_input "$value"; then
-    printf '%s "%s" for %s contains invalid characters at:\n' \
-      "$description" "$value" "${FUNCNAME[$((skip_callers - 1))]}" >&2
+    printf '%s "%s" for %s contains %s at:\n' \
+      "$description" "$value" "${FUNCNAME[$((skip_callers - 1))]}" \
+      'unescaped shell metacharacters or control operators' >&2
     @go.print_stack_trace "$skip_callers" >&2
     exit 1
   fi

tests/file/open-or-dup.bats

@@ -145,7 +145,8 @@ create_file_open_test_go_script() {
   FILE_PATH_OR_FD="$file_path_or_fd" run "$TEST_GO_SCRIPT"
 
   local err_msg="file_path_or_fd \"$file_path_or_fd\" "
-  err_msg+='for @go.open_file_or_duplicate_fd contains invalid characters at:'
+  err_msg+='for @go.open_file_or_duplicate_fd contains '
+  err_msg+='unescaped shell metacharacters or control operators at:'
 
   local expected=("$err_msg"
     "  $TEST_GO_SCRIPT:5 main")

tests/prompt/prompt-for-safe-input.bats

@@ -0,0 +1,95 @@
+#! /usr/bin/env bats
+
+load ../environment
+
+setup() {
+  test_filter
+  @go.create_test_go_script '. "$_GO_USE_MODULES" "prompt"' \
+    'declare prompt="$1"' \
+    'declare default="$2"' \
+    'declare fail_msg="$3"' \
+    'declare response="initial value"' \
+    'declare result' \
+    '@go.prompt_for_safe_input 'response' "$prompt" "$default" "$fail_msg"' \
+    'result="$?"' \
+    'if [[ "$result" -eq "0" ]]; then' \
+    '  printf -- "%s\n" "$response"' \
+    'fi' \
+    'exit "$result"'
+}
+
+teardown() {
+  @go.remove_test_go_rootdir
+}
+
+@test "$SUITE: error if variable not a valid identifier" {
+  @go.create_test_go_script '. "$_GO_USE_MODULES" "prompt"' \
+    '@go.prompt_for_safe_input "invalid;"'
+
+  run "$TEST_GO_SCRIPT"
+  assert_failure
+
+  local err_msg='Input prompt response variable name "invalid;" for '
+  err_msg+='@go.prompt_for_safe_input '
+  err_msg+='contains invalid identifier characters at:'
+
+  assert_lines_match "^${err_msg}\$" \
+    "^  $TEST_GO_SCRIPT:[0-9] main$"
+
+}
+
+@test "$SUITE: reads value with no metacharacters or control operators" {
+  run "$TEST_GO_SCRIPT" $'What is your quest?\n' <<<'To seek the grail!'
+  assert_success 'What is your quest?' \
+    'To seek the grail!'
+}
+
+@test "$SUITE: reads a value with an escaped metacharacter" {
+  run "$TEST_GO_SCRIPT" $'What is your quest?\n' <<<"To seek the grail\;"
+  assert_success 'What is your quest?' \
+    "To seek the grail\;"
+}
+
+@test "$SUITE: fails when reading a value with an unescaped metacharacter" {
+  run "$TEST_GO_SCRIPT" $'What is your quest?\n' <<<'To seek the grail;'
+
+  local err_msg='"To seek the grail;" is an invalid response, as it contains '
+  err_msg+='unescaped shell metacharacters or control operators.'
+
+  assert_failure 'What is your quest?' \
+    "$err_msg"
+}
+
+@test "$SUITE: fails when the default value has an unescaped metacharacter" {
+  run "$TEST_GO_SCRIPT" $'What is your quest?\n' 'To seek the grail;' <<<''
+
+  local err_msg='"To seek the grail;" is an invalid response, as it contains '
+  err_msg+='unescaped shell metacharacters or control operators.'
+
+  assert_failure 'What is your quest? [default: To seek the grail;]' \
+    "$err_msg"
+}
+
+@test "$SUITE: fails when no default or input provided" {
+  run "$TEST_GO_SCRIPT" $'What is your quest?\n' '' 'Auuuuuuuugh!' <<<''
+  assert_failure 'What is your quest?' \
+    'Auuuuuuuugh!'
+}
+
+@test "$SUITE: --or-die exits when the value has an unescaped metacharacter" {
+  @go.create_test_go_script '. "$_GO_USE_MODULES" "prompt"' \
+    'declare response="initial value"' \
+    "@go.prompt_for_safe_input --or-die 'Quest response' 'response' \\" \
+    $'  "What is your quest?\n"'
+
+  run "$TEST_GO_SCRIPT" <<<'To seek the grail;'
+  assert_failure
+
+  local err_msg='^Quest response "To seek the grail;" for '
+  err_msg+='@go.prompt_for_safe_input contains '
+  err_msg+='unescaped shell metacharacters or control operators at:$'
+
+  assert_lines_match 'What is your quest?' \
+    "$err_msg" \
+    "  $TEST_GO_SCRIPT:[0-9] main"
+}

tests/validation.bats

@@ -92,7 +92,7 @@ assert_success_on_valid_input() {
   assert_failure
 
   local err_msg='^input argument "foo;bar" for @go\.validate_input_or_die '
-  err_msg+='contains invalid characters at:$'
+  err_msg+='contains unescaped shell metacharacters or control operators at:$'
 
   assert_lines_match "$err_msg" \
     "  $TEST_GO_SCRIPT:[0-9] main"
@@ -105,7 +105,7 @@ assert_success_on_valid_input() {
   run "$TEST_GO_SCRIPT"
   assert_failure
   assert_lines_match \
-    '^input argument "foo;bar" for test_func contains invalid characters at:$' \
+    '^input argument "foo;bar" for test_func contains unescaped .* at:$' \
     "  $TEST_GO_SCRIPT:[0-9] main"
 }