app-shells/bash: add 5.2_p26-r7 with XTWINOPS support

Xterm is able to push and pop window titles to a stack and there are a
few other terminal emulators that can do so (alacritty and foot being
the only ones that I am aware of at the present time). Take advantage of
this feature so as to reinstate automatic window title setting in the
case that the PTY is owned by sshd(8). Unfortunately, there are a lot of
terminal emulators that falsely advertise themselves as being
xterm-compatible, making it impossible to reliably identify xterm
itself. However, we can reliably identify alacritty and foot so let's
support those two to begin with.

Have the genfun_set_win_title function export a variable named
SHELL_SETS_TITLE upon the first occasion that it is called. Presently,
nothing responds to this variable but the intention is to eventually
have portage respond to it. Portage implements heuristics and behaviours
that are horrifyingly broken. For instance, it considers the mere
presence of PROMPT_COMMAND as somehow proving that the interactive shell
uses it for nothing other than to set the title, despite the fact that:

- the contents of PROMPT_COMMAND may be arbitrarily defined by the user
- the purpose of PROMPT_COMMAND is whatever the user may wish it to be
- nobody in their right mind would export PROMPT_COMMAND
- PROMPT_COMMAND can be an array since 5.1 (making it unexportable)

Worse still, in the event that portage is somehow able to ascertain the
value of PROMPT_COMMAND, it takes its first element and proceeds to
inject its value into an invocation of either sh, $SHELL or bash -c,
irrespective of the consequences. No, I'm not making this up.

As such, the purpose of the SHELL_SETS_TITLE variable is to act as a
straightforward indicator that an interactive shell exists as an
ancestor process and that it will take it upon itself to set a fresh
window title upon its primary prompt being displayed.

Signed-off-by: Kerin Millar <kfm@plushkava.net>
Signed-off-by: Sam James <sam@gentoo.org>

2 files changed, 476 insertions, 0 deletions

diff --git a/app-shells/bash/bash-5.2_p26-r7.ebuild b/app-shells/bash/bash-5.2_p26-r7.ebuild
new file mode 100644
index 000000000000..c46a593c82b0
--- /dev/null
+++ b/app-shells/bash/bash-5.2_p26-r7.ebuild
@@ -0,0 +1,402 @@
+# Copyright 1999-2024 Gentoo Authors
+# Distributed under the terms of the GNU General Public License v2
+
+EAPI=8
+
+VERIFY_SIG_OPENPGP_KEY_PATH=/usr/share/openpgp-keys/chetramey.asc
+inherit flag-o-matic toolchain-funcs prefix verify-sig
+
+# Uncomment if we have a patchset.
+#GENTOO_PATCH_DEV="sam"
+#GENTOO_PATCH_VER="${PV}"
+
+MY_PV=${PV/_p*}
+MY_PV=${MY_PV/_/-}
+MY_P=${PN}-${MY_PV}
+MY_PATCHES=()
+
+# Determine the patchlevel. See ftp://ftp.gnu.org/gnu/bash/bash-5.2-patches/.
+case ${PV} in
+	*_p*)
+		PLEVEL=${PV##*_p}
+		;;
+	9999|*_alpha*|*_beta*|*_rc*)
+		# Set a negative patchlevel to indicate that it's a pre-release.
+		PLEVEL=-1
+		;;
+	*)
+		PLEVEL=0
+esac
+
+# The version of readline this bash normally ships with. Note that we only use
+# the bundled copy of readline for pre-releases.
+READLINE_VER="8.2_p1"
+
+DESCRIPTION="The standard GNU Bourne again shell"
+HOMEPAGE="https://tiswww.case.edu/php/chet/bash/bashtop.html https://git.savannah.gnu.org/cgit/bash.git"
+
+if [[ ${PV} == 9999 ]]; then
+	EGIT_REPO_URI="https://git.savannah.gnu.org/git/bash.git"
+	EGIT_BRANCH=devel
+	inherit git-r3
+else
+	my_urls=( {'mirror://gnu/bash','ftp://ftp.cwru.edu/pub/bash'}/"${MY_P}.tar.gz" )
+
+	# bash-5.1 -> bash51
+	my_p=${PN}$(ver_cut 1-2) my_p=${my_p/.}
+
+	for (( my_patch_idx = 1; my_patch_idx <= PLEVEL; my_patch_idx++ )); do
+		printf -v my_patch_ver %s-%03d "${my_p}" "${my_patch_idx}"
+		my_urls+=( {'mirror://gnu/bash','ftp://ftp.cwru.edu/pub/bash'}/"${MY_P}-patches/${my_patch_ver}" )
+		MY_PATCHES+=( "${DISTDIR}/${my_patch_ver}" )
+	done
+
+	SRC_URI="${my_urls[*]} verify-sig? ( ${my_urls[*]/%/.sig} )"
+
+	unset -v my_urls my_p my_patch_idx my_patch_ver
+fi
+
+if [[ ${GENTOO_PATCH_VER} ]]; then
+	SRC_URI+=" https://dev.gentoo.org/~${GENTOO_PATCH_DEV:?}/distfiles/${CATEGORY}/${PN}/${PN}-${GENTOO_PATCH_VER:?}-patches.tar.xz"
+fi
+
+S=${WORKDIR}/${MY_P}
+
+LICENSE="GPL-3+"
+SLOT="0"
+if (( PLEVEL >= 0 )); then
+	KEYWORDS="~alpha ~amd64 ~arm ~arm64 ~hppa ~ia64 ~loong ~m68k ~mips ~ppc ~ppc64 ~riscv ~s390 ~sparc ~x86 ~amd64-linux ~x86-linux ~arm64-macos ~ppc-macos ~x64-macos ~x64-solaris"
+fi
+IUSE="afs bashlogger examples mem-scramble +net nls plugins pgo +readline"
+
+DEPEND="
+	>=sys-libs/ncurses-5.2-r2:=
+	nls? ( virtual/libintl )
+"
+if (( PLEVEL >= 0 )); then
+	DEPEND+=" readline? ( >=sys-libs/readline-${READLINE_VER}:= )"
+fi
+RDEPEND="
+	${DEPEND}
+"
+# We only need bison (yacc) when the .y files get patched (bash42-005, bash51-011).
+BDEPEND="
+	pgo? ( dev-util/gperf )
+	verify-sig? ( sec-keys/openpgp-keys-chetramey )
+"
+
+# EAPI 8 tries to append it but it doesn't exist here.
+QA_CONFIGURE_OPTIONS="--disable-static"
+
+PATCHES=(
+	#"${WORKDIR}"/${PN}-${GENTOO_PATCH_VER}/
+
+	# Patches to or from Chet, posted to the bug-bash mailing list.
+	"${FILESDIR}/${PN}-5.0-syslog-history-extern.patch"
+	"${FILESDIR}/${PN}-5.2_p15-random-ub.patch"
+	"${FILESDIR}/${PN}-5.2_p15-configure-clang16.patch"
+	"${FILESDIR}/${PN}-5.2_p21-wpointer-to-int.patch"
+	"${FILESDIR}/${PN}-5.2_p21-configure-strtold.patch"
+	"${FILESDIR}/${PN}-5.2_p26-memory-leaks.patch"
+)
+
+pkg_setup() {
+	# bug #7332
+	if is-flag -malign-double; then
+		eerror "Detected bad CFLAGS '-malign-double'.  Do not use this"
+		eerror "as it breaks LFS (struct stat64) on x86."
+		die "remove -malign-double from your CFLAGS mr ricer"
+	fi
+
+	if use bashlogger; then
+		ewarn "The logging patch should ONLY be used in restricted (i.e. honeypot) envs."
+		ewarn "This will log ALL output you enter into the shell, you have been warned."
+	fi
+}
+
+src_unpack() {
+	local patch
+
+	if [[ ${PV} == 9999 ]]; then
+		git-r3_src_unpack
+	else
+		if use verify-sig; then
+			verify-sig_verify_detached "${DISTDIR}/${MY_P}.tar.gz"{,.sig}
+
+			for patch in "${MY_PATCHES[@]}"; do
+				verify-sig_verify_detached "${patch}"{,.sig}
+			done
+		fi
+
+		unpack "${MY_P}.tar.gz"
+
+		if [[ ${GENTOO_PATCH_VER} ]]; then
+			unpack "${PN}-${GENTOO_PATCH_VER}-patches.tar.xz"
+		fi
+	fi
+}
+
+src_prepare() {
+	# Include official patches.
+	(( PLEVEL > 0 )) && eapply -p0 "${MY_PATCHES[@]}"
+
+	# Clean out local libs so we know we use system ones w/releases. The
+	# touch utility is invoked for the benefit of config.status.
+	if (( PLEVEL >= 0 )); then
+		rm -rf lib/{readline,termcap}/* \
+		&& touch lib/{readline,termcap}/Makefile.in \
+		&& sed -i -E 's:\$[{(](RL|HIST)_LIBSRC[)}]/[[:alpha:]_-]*\.h::g' Makefile.in \
+		|| die
+	fi
+
+	# Prefixify hardcoded path names. No-op for non-prefix.
+	hprefixify pathnames.h.in
+
+	# Avoid regenerating docs after patches, bug #407985.
+	sed -i -E '/^(HS|RL)USER/s:=.*:=:' doc/Makefile.in \
+	&& touch -r . doc/* \
+	|| die
+
+	# Sometimes hangs (more noticeable w/ pgo), bug #907403.
+	rm tests/run-jobs || die
+
+	eapply -p0 "${PATCHES[@]}"
+	eapply_user
+}
+
+src_configure() {
+	local -a myconf
+
+	# Upstream only test with Bison and require GNUisms like YYEOF and
+	# YYERRCODE. The former at least may be in POSIX soon:
+	# https://www.austingroupbugs.net/view.php?id=1269.
+	# configure warns on use of non-Bison but doesn't abort. The result
+	# may misbehave at runtime.
+	unset -v YACC
+
+	myconf=(
+		--disable-profiling
+
+		# Force linking with system curses ... the bundled termcap lib
+		# sucks bad compared to ncurses.  For the most part, ncurses
+		# is here because readline needs it.  But bash itself calls
+		# ncurses in one or two small places :(.
+		--with-curses
+
+		$(use_enable mem-scramble)
+		$(use_enable net net-redirections)
+		$(use_enable readline)
+		$(use_enable readline bang-history)
+		$(use_enable readline history)
+		$(use_with afs)
+		$(use_with mem-scramble bash-malloc)
+	)
+
+	# For descriptions of these, see config-top.h.
+	# bashrc/#26952 bash_logout/#90488 ssh/#24762 mktemp/#574426
+	append-cppflags \
+		-DDEFAULT_PATH_VALUE=\'\""${EPREFIX}"/usr/local/sbin:"${EPREFIX}"/usr/local/bin:"${EPREFIX}"/usr/sbin:"${EPREFIX}"/usr/bin:"${EPREFIX}"/sbin:"${EPREFIX}"/bin\"\' \
+		-DSTANDARD_UTILS_PATH=\'\""${EPREFIX}"/bin:"${EPREFIX}"/usr/bin:"${EPREFIX}"/sbin:"${EPREFIX}"/usr/sbin\"\' \
+		-DSYS_BASHRC=\'\""${EPREFIX}"/etc/bash/bashrc\"\' \
+		-DSYS_BASH_LOGOUT=\'\""${EPREFIX}"/etc/bash/bash_logout\"\' \
+		-DNON_INTERACTIVE_LOGIN_SHELLS \
+		-DSSH_SOURCE_BASHRC \
+		$(use bashlogger && echo -DSYSLOG_HISTORY)
+
+	use nls || myconf+=( --disable-nls )
+
+	if (( PLEVEL >= 0 )); then
+		# Historically, we always used the builtin readline, but since
+		# our handling of SONAME upgrades has gotten much more stable
+		# in the PM (and the readline ebuild itself preserves the old
+		# libs during upgrades), linking against the system copy should
+		# be safe.
+		# Exact cached version here doesn't really matter as long as it
+		# is at least what's in the DEPEND up above.
+		export ac_cv_rl_version=${READLINE_VER%%_*}
+
+		# Use system readline only with released versions.
+		myconf+=( --with-installed-readline=. )
+	fi
+
+	if use plugins; then
+		append-ldflags "-Wl,-rpath,${EPREFIX}/usr/$(get_libdir)/bash"
+	else
+		# Disable the plugins logic by hand since bash doesn't provide
+		# a way of doing it.
+		export ac_cv_func_dl{close,open,sym}=no \
+			ac_cv_lib_dl_dlopen=no ac_cv_header_dlfcn_h=no
+
+		sed -i -e '/LOCAL_LDFLAGS=/s:-rdynamic::' configure || die
+	fi
+
+	# bug #444070
+	tc-export AR
+
+	econf "${myconf[@]}"
+}
+
+src_compile() {
+	local -a pgo_generate_flags pgo_use_flags
+	local flag
+
+	# -fprofile-partial-training because upstream notes the test suite isn't
+	# super comprehensive.
+	# https://documentation.suse.com/sbp/all/html/SBP-GCC-10/index.html#sec-gcc10-pgo
+	if use pgo; then
+		pgo_generate_flags=(
+			-fprofile-update=atomic
+			-fprofile-dir="${T}"/pgo
+			-fprofile-generate="${T}"/pgo
+		)
+		pgo_use_flags=(
+			-fprofile-use="${T}"/pgo
+			-fprofile-dir="${T}"/pgo
+		)
+		if flag=$(test-flags-CC -fprofile-partial-training); then
+			pgo_generate_flags+=( "${flag}" )
+			pgo_use_flags+=( "${flag}" )
+		fi
+	fi
+
+	emake CFLAGS="${CFLAGS} ${pgo_generate_flags[*]}"
+	use plugins && emake -C examples/loadables CFLAGS="${CFLAGS} ${pgo_generate_flags[*]}" all others
+
+	# Build Bash and run its tests to generate profiles.
+	if (( ${#pgo_generate_flags[@]} )); then
+		# Used in test suite.
+		unset -v A
+
+		emake CFLAGS="${CFLAGS} ${pgo_generate_flags[*]}" -k check
+
+		if tc-is-clang; then
+			llvm-profdata merge "${T}"/pgo --output="${T}"/pgo/default.profdata || die
+		fi
+
+		# Rebuild Bash using the profiling data we just generated.
+		emake clean
+		emake CFLAGS="${CFLAGS} ${pgo_use_flags[*]}"
+		use plugins && emake -C examples/loadables CFLAGS="${CFLAGS} ${pgo_use_flags[*]}" all others
+	fi
+}
+
+src_test() {
+	# Used in test suite.
+	unset -v A
+
+	default
+}
+
+src_install() {
+	local d f
+
+	default
+
+	my_prefixify() {
+		while read -r; do
+			if [[ $REPLY == *$1* ]]; then
+				REPLY=${REPLY/"/etc/"/"${EPREFIX}/etc/"}
+			fi
+			printf '%s\n' "${REPLY}" || ! break
+		done < "$2" || die
+	}
+
+	dodir /bin
+	mv -- "${ED}"/usr/bin/bash "${ED}"/bin/ || die
+	dosym bash /bin/rbash
+
+	insinto /etc/bash
+	doins "${FILESDIR}"/bash_logout
+	my_prefixify bashrc.d "${FILESDIR}"/bashrc-r1 | newins - bashrc
+
+	insinto /etc/bash/bashrc.d
+	my_prefixify DIR_COLORS "${FILESDIR}"/bashrc.d/10-gentoo-color.bash | newins - 10-gentoo-color.bash
+	newins "${FILESDIR}"/bashrc.d/10-gentoo-title-r1.bash 10-gentoo-title.bash
+	if [[ ! ${EPREFIX} ]]; then
+		doins "${FILESDIR}"/bashrc.d/15-gentoo-bashrc-check.bash
+	fi
+
+	insinto /etc/skel
+	for f in bash{_logout,_profile,rc}; do
+		newins "${FILESDIR}/dot-${f}" ".${f}"
+	done
+
+	if use plugins; then
+		exeinto "/usr/$(get_libdir)/bash"
+		set -- examples/loadables/*.o
+		doexe "${@%.o}"
+
+		insinto /usr/include/bash-plugins
+		doins *.h builtins/*.h include/*.h lib/{glob/glob.h,tilde/tilde.h}
+	fi
+
+	if use examples; then
+		for d in examples/{functions,misc,scripts,startup-files}; do
+			exeinto "/usr/share/doc/${PF}/${d}"
+			docinto "${d}"
+			for f in "${d}"/*; do
+				if [[ ${f##*/} != @(PERMISSION|*README) ]]; then
+					doexe "${f}"
+				else
+					dodoc "${f}"
+				fi
+			done
+		done
+	fi
+
+	# Install bash_builtins.1 and rbash.1.
+	emake -C doc DESTDIR="${D}" install_builtins
+	sed 's:bash\.1:man1/&:' doc/rbash.1 > "${T}"/rbash.1 || die
+	doman "${T}"/rbash.1
+
+	newdoc CWRU/changelog ChangeLog
+	dosym bash.info /usr/share/info/bashref.info
+}
+
+pkg_preinst() {
+	if [[ -e ${EROOT}/etc/bashrc ]] && [[ ! -d ${EROOT}/etc/bash ]]; then
+		mkdir -p -- "${EROOT}"/etc/bash \
+		&& mv -f -- "${EROOT}"/etc/bashrc "${EROOT}"/etc/bash/ \
+		|| die
+	fi
+}
+
+pkg_postinst() {
+	local old_ver
+
+	# If /bin/sh does not exist, provide it.
+	if [[ ! -e ${EROOT}/bin/sh ]]; then
+		ln -sf -- bash "${EROOT}"/bin/sh || die
+	fi
+
+	read -r old_ver <<<"${REPLACING_VERSIONS}"
+	if [[ ! $old_ver ]]; then
+		:
+	elif ver_test "$old_ver" -ge "5.2" && ver_test "$old_ver" -ge "5.2_p26-r7"; then
+		return
+	fi
+
+	while read -r; do ewarn "${REPLY}"; done <<'EOF'
+Files under /etc/bash/bashrc.d must now have a suffix of .sh or .bash.
+
+Gentoo now defaults to defining PROMPT_COMMAND as an array. Depending on the
+characteristics of the operating environment, it may contain a command to set
+the terminal's window title. Those who were already choosing to customise the
+PROMPT_COMMAND variable are now advised to append their commands like so:
+
+PROMPT_COMMAND+=('custom command goes here')
+
+Gentoo no longer defaults to having bash set the window title in the case
+that the terminal is controlled by sshd(8), unless screen or tmux are in use
+or the terminal reliably supports saving and restoring the title (as
+alacritty and foot do). Those wanting to set the title unconditionally may
+adjust ~/.bashrc - or create a custom /etc/bash/bashrc.d drop-in - to set
+PROMPT_COMMMAND like so:
+
+PROMPT_COMMAND=(genfun_set_win_title)
+
+Those who would prefer for bash never to interfere with the window title may
+now opt out of the default title setting behaviour, either with the "unset -v
+PROMPT_COMMAND" command or by re-defining PROMPT_COMMAND as desired.
+EOF
+}
diff --git a/app-shells/bash/files/bashrc.d/10-gentoo-title-r1.bash b/app-shells/bash/files/bashrc.d/10-gentoo-title-r1.bash
new file mode 100644
index 000000000000..1dc7b63bf422
--- /dev/null
+++ b/app-shells/bash/files/bashrc.d/10-gentoo-title-r1.bash
@@ -0,0 +1,74 @@
+# /etc/bash/bashrc.d/10-gentoo-title.bash
+
+# For information regarding the control sequences used, please refer to
+# https://invisible-island.net/xterm/ctlseqs/ctlseqs.html.
+
+genfun_set_win_title() {
+	# Advertise the fact that the presently running interactive shell will
+	# update the title. Doing so allows for its subprocesses to determine
+	# whether it is safe to set the title of their own accord. Note that 0
+	# refers to the value of Ps within the OSC Ps ; Pt BEL sequence.
+	export SHELL_SETS_TITLE=0
+
+	# Assigns the basename of the current working directory, having
+	# sanitised it with @Q parameter expansion. Useful for paths containing
+	# newlines and such. As a special case, names consisting entirely of
+	# graphemes shall not undergo the expansion, for reasons of cleanliness.
+	genfun_sanitise_cwd() {
+		_cwd=${PWD##*/}
+		if [[ ! ${_cwd} ]]; then
+			_cwd=${PWD}
+		elif [[ ${_cwd} == *[![:graph:]]* ]]; then
+			_cwd=${_cwd@Q}
+		fi
+	}
+
+	# Sets the window title with the Set Text Parameters control sequence.
+	# For screen, the sequence defines the hardstatus (%h) and for tmux, the
+	# pane_title (#T). For graphical terminal emulators, it is normal for
+	# the title bar to be affected.
+	genfun_set_win_title() {
+		genfun_sanitise_cwd
+		printf '\033]0;%s@%s - %s\007' "${USER}" "${HOSTNAME%%.*}" "${_cwd}"
+	}
+
+	genfun_set_win_title
+}
+
+unset -v SHELL_SETS_TITLE
+
+# Determine whether the terminal can handle the Set Text Parameters sequence.
+# The only terminals permitted here are those for which there is empirical
+# evidence that the sequence is supported and that the UTF-8 character encoding
+# is handled correctly. Quite rightly, this precludes many vintage terminals.
+case ${TERM} in
+	screen*|tmux*)
+		;;
+	alacritty|foot*)
+		# The terminal emulator also supports XTWINOPS. If the PTY was
+		# created by sshd(8) then push the current window title to the
+		# stack and arrange for it to be popped upon exiting. Xterm also
+		# supports this but there are far too many terminal emulators
+		# that falsely identify as being xterm-compatible.
+		if [[ ${SSH_TTY} && ${SSH_TTY} == "$(tty)" ]]; then
+			trap 'printf "\033[23;0t"' EXIT
+			printf '\033[22;0t'
+		fi
+		;;
+	rxvt-unicode*|st-256color|xterm*)
+		# If the PTY was created by sshd(8) then proceed no further.
+		# Alas, there exist many operating environments in which the
+		# title would otherwise not be restored upon ssh(1) exiting.
+		# Those wanting for the title to be set regardless may adjust
+		# ~/.bashrc or create a bashrc.d drop-in to set PROMPT_COMMAND.
+		# For example, PROMPT_COMMAND=(genfun_set_win_title).
+		if [[ ${SSH_TTY} && ${SSH_TTY} == "$(tty)" ]]; then
+			return
+		fi
+		;;
+	*)
+		return
+esac
+
+# Arrange for the title to be updated each time the primary prompt is displayed.
+PROMPT_COMMAND+=('genfun_set_win_title')