commit: 282fbd3bc2cca32b1a83c28cb9649de46cf404da
Author: Kerin Millar <kfm <AT> plushkava <DOT> net>
AuthorDate: Thu Aug 1 06:30:19 2024 +0000
Commit: Sam James <sam <AT> gentoo <DOT> org>
CommitDate: Fri Aug 2 16:21:12 2024 +0000
URL:
https://gitweb.gentoo.org/proj/gentoo-functions.git/commit/?id=282fbd3b
Render quote_args() robust and implement a test case
Coerce the effective character set as being C (US-ASCII) in the course
of executing awk(1). Some implementations are strict and will otherwise
fail in situations where the bytes cannot be decoded.
$ uname -o
Darwin
$ echo "$LC_ALL"
en_GB.UTF-8
$ printf '\200' | awk '/[\001-\037\177-\377]/'
awk: towc: multibyte conversion failure on: ''
In the above case, awk aborts because it has a need to decode the input,
which turns out not to be valid UTF-8. Now, it is rather beyond the
purview of quote_args() to guarantee that its parameters adhere to any
particular character encoding. Fortunately, for it to contend with
strings on a byte-by-byte basis is acceptable.
Refactor the code somewhat. The behaviour has been adjusted so to be
virtually identical to that of the "${*@Q}" expansion in bash, with the
exception that the ESC character is rendered as $'\e' instead of $'\E'.
Such an exception is necessary for POSIX-1.2024 conformance, wherein
dollar-single-quotes are now a standard feature (see section 2.2.4 of
the Shell Command Language).
Revise the comment preceding the function so as to accurately document
its behaviour.
Finally, add a test case. It works by calling quote_args for every
possible single-byte string before calculating a CRC checksum for the
cumulative output and comparing it against a pre-determined value.
Signed-off-by: Kerin Millar <kfm <AT> plushkava.net>
functions.sh | 65 ++++++++++++++++++++++++++++++++++++----------------------
test-functions | 20 ++++++++++++++++++
2 files changed, 60 insertions(+), 25 deletions(-)
diff --git a/functions.sh b/functions.sh
index faacdca..036e3a7 100644
--- a/functions.sh
+++ b/functions.sh
@@ -425,47 +425,62 @@ parallel_run()
#
# Prints the positional parameters in a format that may be reused as shell
# input. For each considered, it shall be determined whether its value contains
-# any non-printable characters in lieu of the US-ASCII character set. If no
such
-# characters are found, the value shall have each instance of <apostrophe> be
-# replaced by <apostrophe><backslash><apostrophe><apostrophe> before being
-# enclosed by a pair of <apostrophe> characters. Otherwise, non-printable
-# characters shall be replaced by octal escape sequences, <apostrophe> by
-# <backslash><apostrophe> and <backslash> by <backslash><backslash>, prior to
-# the value being given a prefix of <dollar-sign><apostrophe> and a suffix of
-# <apostrophe>, per POSIX-1.2024. Finally, the resulting values shall be
printed
-# as <space> separated. The latter quoting strategy can be suppressed by
setting
-# the POSIXLY_CORRECT variable as non-empty in the environment.
+# any bytes that are either outside the scope of the US-ASCII character set or
+# which are considered as non-printable. If no such bytes are found, the value
+# shall have each instance of <apostrophe> be replaced by <apostrophe>
+# <backslash> <apostrophe> <apostrophe> before being enclosed by a pair of
+# <apostrophe> characters. However, as a special case, a value consisting of a
+# single <apostrophe> shall be replaced by <backslash> <apostrophe>.
+#
+# If any such bytes are found, the value shall instead be requoted in a manner
+# that conforms with section 2.2.4 of the Shell Command Language, wherein the
+# the use of dollar-single-quotes sequences is described. Such sequences are
+# standard as of POSIX-1.2024. However, as of August 2024, many implementations
+# lack support for this feature. So as to mitigate this state of affairs, the
+# use of dollar-single-quotes may be suppressed by setting POSIXLY_CORRECT as a
+# non-empty string.
#
quote_args()
{
- awk -v q=\' -f - -- "$@" <<-'EOF'
+ LC_ALL=C awk -v q=\' -f - -- "$@" <<-'EOF'
+ function init_table() {
+ # Iterate over ranges \001-\037 and \177-\377.
+ for (i = 1; i <= 255; i += (i == 31 ? 96 : 1)) {
+ char = sprintf("%c", i)
+ seq_by[char] = sprintf("%03o", i)
+ }
+ seq_by["\007"] = "a"
+ seq_by["\010"] = "b"
+ seq_by["\011"] = "t"
+ seq_by["\012"] = "n"
+ seq_by["\013"] = "v"
+ seq_by["\014"] = "f"
+ seq_by["\015"] = "r"
+ seq_by["\033"] = "e"
+ seq_by["\047"] = "'"
+ seq_by["\134"] = "\\"
+ }
BEGIN {
strictly_posix = length(ENVIRON["POSIXLY_CORRECT"])
argc = ARGC
ARGC = 1
for (arg_idx = 1; arg_idx < argc; arg_idx++) {
arg = ARGV[arg_idx]
- if (strictly_posix || arg !~ /[\001-\037\177]/) {
+ if (arg == q) {
+ word = "\\" q
+ } else if (strictly_posix || arg !~
/[\001-\037\177-\377]/) {
gsub(q, q "\\" q q, arg)
word = q arg q
} else {
- # Use $'' quoting per POSIX-1.2024
- if (! ("\001" in ord_by)) {
- for (i = 1; i < 32; i++) {
- char = sprintf("%c", i)
- ord_by[char] = i
- }
- ord_by["\177"] = 127
+ # Use $'' quoting per POSIX-1.2024.
+ if (! ("\001" in seq_by)) {
+ init_table()
}
word = "$'"
for (i = 1; i <= length(arg); i++) {
char = substr(arg, i, 1)
- if (char == "\\") {
- word = word "\\\\"
- } else if (char == q) {
- word = word "\\'"
- } else if (char in ord_by) {
- word = word "\\"
sprintf("%03o", ord_by[char])
+ if (char in seq_by) {
+ word = word "\\" seq_by[char]
} else {
word = word char
}
diff --git a/test-functions b/test-functions
index f37477c..ef2aa98 100755
--- a/test-functions
+++ b/test-functions
@@ -882,6 +882,25 @@ test_contains_any() {
iterate_tests 5 "$@"
}
+test_quote_args() {
+ testnum=$((testnum + 1))
+ retval=0
+ i=0
+ while [ "$(( i += 1 ))" -le 255 ]; do
+ fmt=$(printf '\%o' "$i")
+ str=$(printf "$fmt.")
+ POSIXLY_CORRECT= quote_args "${str%.}" || break
+ done | cksum | {
+ read -r cksum _
+ if [ "${cksum}" != "380900690" ]; then
+ printf 'not '
+ retval=1
+ fi
+ printf 'ok %d - quote_args output test (expected cksum
380900690, got %s)\n' "${testnum}" "${cksum}"
+ return "${retval}"
+ }
+}
+
iterate_tests() {
slice_width=$1
shift
@@ -959,6 +978,7 @@ else
#test_substr || rc=1
test_contains_all || rc=1
test_contains_any || rc=1
+ test_quote_args || rc=1
fi
cleanup_tmpdir
