feat(wasm-gui M8.3): libfm (LXDE data layer) cross-compiles + lists the kernel VFS, all wasm

libfm-extra -> menu-cache -> libfm-gtk3 all cross-compile from UNMODIFIED upstream and libfm
enumerates a kernel-VFS directory headless (19 entries listed, clean exit). Proof:
~/tmp/gui-progress/proof-m8.3-libfm-lists-vfs.txt. Per constraint #5 every gap is platform/
toolchain-layer:
- toolchain/openbox-compat.c: execv/execve stubs (no process-image replacement in the sandbox) +
  ns_get16/ns_get32 (gio resolver DNS field readers, implemented).
- toolchain/wasi-compat.c: strsignal made weak (libwasi-emulated-signal owns the real one; strong
  caused a duplicate-symbol link error when libfm pulls both).
- toolchain/host-bin/: fake intltool tools (intltool unavailable; only needed for translations,
  which we --disable-nls) + a stub perl XML::Parser to satisfy intltool's configure check.
- scripts/build-libfm.sh + test-m8-libfm.sh: reproducible build (libfm-extra --with-extra-only,
  menu-cache lib-only since menu-cache-gen needs fork/exec, libfm --with-gtk=3 --disable-old-actions
  to skip the Vala component) + the headless dir-listing acceptance test.
The menu-cache freedesktop enumeration (menu-cache-gen via fork/exec) is a separate wasi concern;
the libfm folder/listing path is proven.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: NathanFlurry

experiments/wasm-gui/guest-xclient/libfm-test.c

@@ -0,0 +1,49 @@
+/* M8.3 headless test: drive libfm (the LXDE data layer) to list a directory of the kernel VFS, proving
+ * the cross-compiled libfm + glib/gio stack runs end to end in wasm. No X / no GUI: libfm's FmFolder
+ * loads asynchronously on the GLib main loop, so we run a GMainLoop until "finish-loading", then print
+ * the entries. Diagnostics to stderr (the host captures it). Usage: libfm-test [dir] (default /usr/share). */
+#include <libfm/fm.h>
+#include <glib.h>
+
+static GMainLoop *loop;
+static int rc = 1;
+
+static void on_finish(FmFolder *folder, gpointer data) {
+    (void) data;
+    FmFileInfoList *files = fm_folder_get_files(folder);
+    guint n = files ? fm_file_info_list_get_length(files) : 0;
+    g_printerr("LIBFM-TEST: folder loaded, %u entries:\n", n);
+    GList *l = files ? fm_file_info_list_peek_head_link(files) : NULL;
+    int i = 0;
+    for (; l && i < 25; l = l->next, ++i) {
+        FmFileInfo *fi = (FmFileInfo *) l->data;
+        g_printerr("  - %s\n", fm_file_info_get_name(fi));
+    }
+    if (n > 0) { g_printerr("LIBFM-TEST: PASS (listed %u entries via libfm)\n", n); rc = 0; }
+    else        g_printerr("LIBFM-TEST: FAIL (folder loaded but empty)\n");
+    g_main_loop_quit(loop);
+}
+
+static gboolean timeout_fail(gpointer d) {
+    (void) d;
+    g_printerr("LIBFM-TEST: FAIL (timeout — folder never finished loading)\n");
+    g_main_loop_quit(loop);
+    return G_SOURCE_REMOVE;
+}
+
+int main(int argc, char **argv) {
+    g_printerr("LIBFM-TEST: fm_init\n");
+    fm_init(NULL);
+    loop = g_main_loop_new(NULL, FALSE);
+    const char *dir = argc > 1 ? argv[1] : "/";
+    g_printerr("LIBFM-TEST: listing %s\n", dir);
+    FmFolder *folder = fm_folder_from_path_name(dir);
+    if (!folder) { g_printerr("LIBFM-TEST: FAIL (no folder)\n"); return 1; }
+    if (fm_folder_is_loaded(folder))
+        on_finish(folder, NULL);
+    else
+        g_signal_connect(folder, "finish-loading", G_CALLBACK(on_finish), NULL);
+    g_timeout_add(20000, timeout_fail, NULL);
+    g_main_loop_run(loop);
+    return rc;
+}

experiments/wasm-gui/scripts/build-libfm.sh

@@ -0,0 +1,62 @@
+#!/usr/bin/env bash
+# M8.3: cross-compile the LXDE data layer (libfm-extra -> menu-cache -> libfm-gtk3) to
+# wasm32-wasip1-threads, from UNMODIFIED upstream. Dep order is circular-ish: menu-cache needs
+# libfm-extra, full libfm needs menu-cache. All wasi gaps fixed in the platform/toolchain layer
+# (constraint #5): see toolchain/openbox-compat.c (getpwuid/exec*/ns_get*), compat-include/grp.h,
+# wasi-compat.c (weak strsignal), libhostcompat.a.
+#
+# Host build-tool shims (intltool is unavailable; only needed for translations, which we --disable-nls):
+#   toolchain/host-bin/{intltool-update,intltoolize,intltool-merge,intltool-extract} + a stub
+#   perl5/XML/Parser.pm. The real gettext tools need libxml2.so.2 on LD_LIBRARY_PATH.
+set -uo pipefail
+cd "$(dirname "$0")/.."
+EXP="$(pwd)"; REPO="$(cd ../.. && pwd)"
+export SECURE_EXEC_WASM_THREADS=1
+source "$EXP/toolchain/cross-env.sh"
+TP="$EXP/third_party"
+export PATH="$EXP/toolchain/host-bin:/home/linuxbrew/.linuxbrew/bin:$PATH"
+export PERL5LIB="$EXP/toolchain/host-bin/perl5:${PERL5LIB:-}"
+# the host gettext tools (xgettext/msgfmt) need libxml2.so.2; point at the nix copy if present
+XML2=$(find /nix/store -maxdepth 2 -name "libxml2.so.2" 2>/dev/null | head -1)
+[ -n "$XML2" ] && export LD_LIBRARY_PATH="$(dirname "$XML2"):${LD_LIBRARY_PATH:-}"
+newest_config_sub() { echo "$TP/libX11-threads/config.sub"; }
+LDADD_HOST="-lhostcompat -Wl,--allow-undefined"
+
+# 0. libhostcompat.a must exist (build-openbox.sh makes it; rebuild here too in case)
+"$CC" $CFLAGS -c "$EXP/toolchain/openbox-compat.c" -o "$EXP/toolchain/openbox-compat.o" 2>/dev/null
+"$AR" rcs "$PREFIX/lib/libhostcompat.a" "$EXP"/toolchain/threads-libs/{host_socket,host_pipe_dup,override_fcntl}.o \
+  "$EXP/toolchain/wasi-compat-threads.o" "$EXP/toolchain/openbox-compat.o"
+
+cfg() { # cfg <dir> <extra configure args...>
+  local d="$1"; shift
+  cp "$(newest_config_sub)" "$(dirname "$(newest_config_sub)")/config.guess" "$TP/$d/" 2>/dev/null
+  ( cd "$TP/$d" && export LDFLAGS="$LDFLAGS $LDADD_HOST" && make distclean >/dev/null 2>&1
+    ./configure $CROSS_CONFIGURE_ARGS --disable-maintainer-mode --disable-nls --disable-gtk-doc "$@" \
+      > "/tmp/conf-$d.log" 2>&1 && touch aclocal.m4 configure config.h.in Makefile.in */Makefile.in 2>/dev/null )
+}
+
+# 1. libfm-extra (the non-GTK utility lib; menu-cache requires it)
+if [ ! -f "$PREFIX/lib/libfm-extra.a" ]; then
+  cd "$TP"; [ -d libfm ] || { mkdir -p libfm && tar xf libfm.tar -C libfm --strip-components=1; }
+  [ -d libfm-threads ] || cp -r libfm libfm-threads
+  cfg libfm-threads --with-extra-only
+  ( cd "$TP/libfm-threads" && export LDFLAGS="$LDFLAGS $LDADD_HOST" && make -j4 && make install ) >/tmp/make-libfmextra.log 2>&1 \
+    && echo "  OK libfm-extra" || { echo "  FAIL libfm-extra"; exit 1; }
+fi
+
+# 2. menu-cache (library only; menu-cache-gen needs fork/exec at runtime, not built)
+if [ ! -f "$PREFIX/lib/libmenu-cache.a" ]; then
+  cd "$TP"; [ -d menu-cache ] || { mkdir -p menu-cache && tar xf menu-cache.tar -C menu-cache --strip-components=1; }
+  [ -d menu-cache-threads ] || cp -r menu-cache menu-cache-threads
+  cfg menu-cache-threads
+  ( cd "$TP/menu-cache-threads" && export LDFLAGS="$LDFLAGS $LDADD_HOST" \
+    && make -C libmenu-cache -j4 && make -C libmenu-cache install \
+    && cp libmenu-cache.pc "$PREFIX/lib/pkgconfig/" 2>/dev/null ) >/tmp/make-menucache.log 2>&1 \
+    && echo "  OK menu-cache (lib)" || { echo "  FAIL menu-cache"; exit 1; }
+fi
+
+# 3. full libfm (gtk3). --disable-old-actions skips the Vala 'custom actions' (no valac here).
+cd "$TP/libfm-threads"; cfg libfm-threads --with-gtk=3 --disable-old-actions
+( cd "$TP/libfm-threads" && export LDFLAGS="$LDFLAGS $LDADD_HOST" && make -j4 && make install ) >/tmp/make-libfm.log 2>&1 \
+  && echo "OK: libfm built — $(ls $PREFIX/lib/libfm*.a | xargs -n1 basename | tr '\n' ' ')" \
+  || { echo "FAIL libfm"; tail -12 /tmp/make-libfm.log; exit 1; }

experiments/wasm-gui/scripts/test-m8-libfm.sh

@@ -0,0 +1,28 @@
+#!/usr/bin/env bash
+# M8.3 acceptance: build the libfm-test guest and run it headless (no X) to prove the cross-compiled
+# libfm + glib/gio data layer enumerates a kernel-VFS directory in wasm. PASS = libfm lists entries
+# and exits 0. (The menu-cache freedesktop enumeration goes through menu-cache-gen which needs
+# fork/exec at runtime — tracked separately; this proves the libfm folder/listing path.)
+set -uo pipefail
+cd "$(dirname "$0")/.."
+EXP="$(pwd)"; REPO="$(cd ../.. && pwd)"
+export SECURE_EXEC_WASM_THREADS=1
+source "$EXP/toolchain/cross-env.sh"
+HOST="$REPO/target/debug/wasm-gui-host"; SIDECAR="$REPO/target/debug/secure-exec-sidecar"
+[ -f "$PREFIX/lib/libfm.a" ] || bash "$EXP/scripts/build-libfm.sh" || { echo "libfm build failed"; exit 1; }
+
+WASMSUB="wasm32-wasip1-threads"
+SETJMP="$WSDK/share/wasi-sysroot/lib/$WASMSUB/libsetjmp.a"; LIBC="$THREADS_SYSROOT/lib/$WASMSUB/libc.a"
+HOSTOBJS="$EXP/toolchain/threads-libs/host_socket.o $EXP/toolchain/threads-libs/host_pipe_dup.o $EXP/toolchain/threads-libs/override_fcntl.o"
+PCCF=$(PKG_CONFIG_LIBDIR="$PREFIX/lib/pkgconfig" pkg-config --cflags libfm gio-2.0)
+PCLIBS=$(PKG_CONFIG_LIBDIR="$PREFIX/lib/pkgconfig" pkg-config --libs libfm gio-2.0)
+"$CC" $CFLAGS $PCCF -I"$PREFIX/include" -c "$EXP/guest-xclient/libfm-test.c" -o /tmp/libfm-test.o || exit 1
+"$CC" $LDFLAGS -Wl,--allow-undefined -o "$EXP/libfm-test.wasm" /tmp/libfm-test.o \
+  "$EXP/toolchain/wasi-compat-threads.o" $HOSTOBJS $PCLIBS -lhostcompat -lwasi-emulated-signal "$SETJMP" "$LIBC" || exit 1
+export PATH="/home/linuxbrew/.linuxbrew/bin:$PATH"
+wasm-opt --fpcast-emu --enable-bulk-memory --enable-threads -O0 "$EXP/libfm-test.wasm" -o /tmp/lf.fp && mv /tmp/lf.fp "$EXP/libfm-test.wasm"
+echo "built libfm-test.wasm ($(stat -c%s "$EXP/libfm-test.wasm")b)"
+
+out="$(env -u DISPLAY "$HOST" --exec --guest "$EXP/libfm-test.wasm" --timeout 35 --sidecar "$SIDECAR" 2>&1)"
+echo "$out" | grep -E "LIBFM-TEST" | grep -v NETWRITE
+if echo "$out" | grep -q "LIBFM-TEST: PASS"; then echo "M8.3 LIBFM: PASS"; exit 0; else echo "M8.3 LIBFM: FAIL"; exit 1; fi

experiments/wasm-gui/toolchain/host-bin/intltool-extract

@@ -0,0 +1,2 @@
+#!/usr/bin/env bash
+exit 0

experiments/wasm-gui/toolchain/host-bin/intltool-merge

@@ -0,0 +1,4 @@
+#!/usr/bin/env bash
+args=("$@"); n=${#args[@]}
+in="${args[$((n-2))]}"; out="${args[$((n-1))]}"
+if [ -f "$in" ]; then sed -E 's/^_([A-Za-z0-9]+=)/\1/' "$in" > "$out"; else exit 0; fi

experiments/wasm-gui/toolchain/host-bin/intltool-update

@@ -0,0 +1,2 @@
+#!/usr/bin/env bash
+case "$1" in --version|-V) echo "intltool-update (intltool) 0.51.0";; *) exit 0;; esac

experiments/wasm-gui/toolchain/host-bin/intltoolize

@@ -0,0 +1,2 @@
+#!/usr/bin/env bash
+exit 0

experiments/wasm-gui/toolchain/host-bin/perl5/XML/Parser.pm

@@ -0,0 +1,8 @@
+# Stub XML::Parser: intltool's configure requires the module to exist, but we build with --disable-nls
+# and our intltool-extract/-merge shims do not parse XML, so a no-op package satisfies the check.
+package XML::Parser;
+sub new { return bless {}, shift }
+sub setHandlers { }
+sub parse { }
+sub parsefile { }
+1;

experiments/wasm-gui/toolchain/openbox-compat.c

@@ -41,3 +41,16 @@ int getpwuid_r(uid_t uid, struct passwd *pwd, char *buf, size_t buflen, struct p
     *result = pwd;
     return 0;
 }
+
+/* libfm/gio reference these. exec* isn't supported in the sandbox (no process-image replacement);
+ * stub to failure. ns_get16/ns_get32 are trivial big-endian DNS field readers (gio's resolver);
+ * implement them (harmless, correct). */
+int execv(const char *p, char *const a[]) { (void)p; (void)a; return -1; }
+int execve(const char *p, char *const a[], char *const e[]) { (void)p; (void)a; (void)e; return -1; }
+unsigned ns_get16(const unsigned char *cp) {
+    return cp ? (((unsigned)cp[0] << 8) | (unsigned)cp[1]) : 0u;
+}
+unsigned long ns_get32(const unsigned char *cp) {
+    return cp ? (((unsigned long)cp[0] << 24) | ((unsigned long)cp[1] << 16) |
+                 ((unsigned long)cp[2] << 8) | (unsigned long)cp[3]) : 0ul;
+}

experiments/wasm-gui/toolchain/wasi-compat.c

@@ -85,7 +85,9 @@ char *inet_ntoa(unsigned in) {
 int seteuid(unsigned u) { (void)u; return 0; }
 int setuid(unsigned u) { (void)u; return 0; }
 int setgid(unsigned g) { (void)g; return 0; }
-char *strsignal(int s) { (void)s; return (char *)"signal"; }
+/* weak: libwasi-emulated-signal provides a real strsignal; ours is only a fallback when that lib
+ * isn't linked. Strong here caused a duplicate-symbol link error in guests (libfm) that pull both. */
+__attribute__((weak)) char *strsignal(int s) { (void)s; return (char *)"signal"; }
 /* twm (WM) references these; stubbed: the WM runs in a single sandboxed process with no
    subprocess exec, no real uid, and uses tempnam only for a session id. */
 int execlp(const char *f, const char *a, ...) { (void)f; (void)a; return -1; }