Report a denied UNSLOTH_LOCAL_LLAMA_CPP_DIR instead of aborting on errexit (#8143)

* Report a denied UNSLOTH_LOCAL_LLAMA_CPP_DIR instead of aborting on errexit

* Report a denied ancestor and stop on a denied install parent

Two gaps in the first pass, both reproduced.

A build under an unsearchable ancestor cannot be stat'd, so `[ ! -d ]` read it as
missing and setup said "does not exist", sending the user to correct a path that
was already right. `_report_denied_ancestor` walks up to the deepest ancestor it
can stat and reports that one, so the message names the directory that actually
needs the permission change. A genuinely absent path still reports as missing.

Keeping the textual path when the install parent could not be canonicalized only
moved the abort: `rm -rf` fails, `[ -e ]` is false because the parent cannot be
stat'd, and the following `ln -sfn` then aborts under errexit with no
[TAURI:ERROR]. Nothing can be written under a parent we cannot search, so report
there instead of continuing.

* Follow symlinks and terminate dirname options when locating a denied ancestor

* Strip trailing slashes before probing for a symlinked denied ancestor

* Tighten the denied-ancestor comments in setup.sh and its test

---------

Co-authored-by: danielhanchen <moonshotaisubstack@gmail.com>

studio/setup.sh

@@ -978,20 +978,18 @@ _studio_owned_adoptable() {
     [ -f "$1/UNSLOTH_WHISPER_PREBUILT_INFO.json" ] && return 0
     return 1
 }
-# Search (+x), not read (+r), is what the marker probes need: inside a directory
-# we cannot search every probe reports absent, so our own install reads as someone else's.
+# Marker probes need search (+x), not read (+r): in an unsearchable dir every probe reports absent, so our install looks foreign.
 _studio_dir_unsearchable() {
     [ -d "$1" ] || return 1
-    ( cd "$1" ) 2>/dev/null && return 1
+    ( cd -- "$1" ) 2>/dev/null && return 1
     return 0
 }
 
-# Also needs +r, for callers that list or replace the tree: mode 111 is searchable
-# but still fails install_llama_prebuilt.py.
+# Also needs +r for callers that list or replace the tree: mode 111 is searchable but still fails install_llama_prebuilt.py.
 _studio_dir_unreadable() {
     [ -d "$1" ] || return 1
     _studio_dir_unsearchable "$1" && return 0
-    ls -A "$1" >/dev/null 2>&1 && return 1
+    ls -A -- "$1" >/dev/null 2>&1 && return 1
     return 0
 }
 
@@ -1018,6 +1016,41 @@ _path_access_denied() {
     setup_fail 1 "Permission denied reading the existing $_pad_label at $_pad_dir. Delete or rename that folder (Unsloth reinstalls it) or restore access, then re-run setup. Reinstalling the app does not reset it."
 }
 
+# POSIX follows a final symlink when the path ends in /, so "link/" is never -L. Strip it, but never past the root.
+_studio_rstrip_slash() {
+    _srs_path="$1"
+    while [ "$_srs_path" != "/" ] && [ "${_srs_path%/}" != "$_srs_path" ]; do
+        _srs_path="${_srs_path%/}"
+    done
+    printf '%s' "$_srs_path"
+}
+
+# An unsearchable ancestor makes a real path read as missing. Walk up to the deepest
+# ancestor we can stat and report it as the blocker; stay quiet if the path is just absent.
+_report_denied_ancestor() {
+    _rda_probe="$(_studio_rstrip_slash "$1")"
+    _rda_hops=0
+    while [ ! -e "$_rda_probe" ] && [ "$_rda_probe" != "/" ] && [ "$_rda_probe" != "." ]; do
+        # An unfollowable symlink is the deepest name we have, so walk its target:
+        # the denied ancestor lives there. The hop cap breaks symlink cycles.
+        if [ -L "$_rda_probe" ] && [ "$_rda_hops" -lt 40 ]; then
+            _rda_hops=$((_rda_hops + 1))
+            _rda_target="$(readlink -- "$_rda_probe")" || break
+            case "$_rda_target" in
+                /*) _rda_probe="$_rda_target" ;;
+                *) _rda_probe="$(dirname -- "$_rda_probe")/$_rda_target" ;;
+            esac
+            _rda_probe="$(_studio_rstrip_slash "$_rda_probe")"
+            continue
+        fi
+        # -- keeps a leading-dash path an operand, not a dirname option.
+        _rda_probe="$(dirname -- "$_rda_probe")"
+    done
+    if _studio_dir_unsearchable "$_rda_probe"; then
+        _path_access_denied "$_rda_probe" "$2" owner-unverified
+    fi
+}
+
 _assert_studio_owned_or_absent() {
     _aso_dir="$1"
     _aso_label="$2"
@@ -1948,10 +1981,17 @@ _has_local_llama_server() {
 _LOCAL_LLAMA_CPP_LINKED=false
 if [ -n "${UNSLOTH_LOCAL_LLAMA_CPP_DIR:-}" ]; then
     if [ ! -d "$UNSLOTH_LOCAL_LLAMA_CPP_DIR" ]; then
+        # A build under an unsearchable ancestor cannot be stat'd, so report permissions
+        # rather than sending the user to fix a path that is already correct.
+        _report_denied_ancestor "$UNSLOTH_LOCAL_LLAMA_CPP_DIR" "UNSLOTH_LOCAL_LLAMA_CPP_DIR"
         step "llama.cpp" "UNSLOTH_LOCAL_LLAMA_CPP_DIR does not exist: $UNSLOTH_LOCAL_LLAMA_CPP_DIR" "$C_ERR"
         setup_fail 1 "UNSLOTH_LOCAL_LLAMA_CPP_DIR does not exist: $UNSLOTH_LOCAL_LLAMA_CPP_DIR"
     fi
-    _RESOLVED_LOCAL="$(CDPATH= cd -P -- "$UNSLOTH_LOCAL_LLAMA_CPP_DIR" && pwd -P)"
+    # In an if condition so a denied dir reports instead of tripping errexit.
+    if ! _RESOLVED_LOCAL="$(CDPATH= cd -P -- "$UNSLOTH_LOCAL_LLAMA_CPP_DIR" 2>/dev/null && pwd -P)"; then
+        # owner-unverified: this is the user's own tree, never advise deleting it.
+        _path_access_denied "$UNSLOTH_LOCAL_LLAMA_CPP_DIR" "UNSLOTH_LOCAL_LLAMA_CPP_DIR" owner-unverified
+    fi
     # Canonicalize the install path the same way before comparing: _RESOLVED_LOCAL
     # is fully resolved, but LLAMA_CPP_DIR is textual ($UNSLOTH_HOME/llama.cpp). If
     # $HOME (or UNSLOTH_HOME) contains a symlink, the two never match even when the
@@ -1961,7 +2001,13 @@ if [ -n "${UNSLOTH_LOCAL_LLAMA_CPP_DIR:-}" ]; then
     _CANON_LLAMA_CPP_DIR="$LLAMA_CPP_DIR"
     _LLAMA_CPP_PARENT="$(dirname "$LLAMA_CPP_DIR")"
     if [ -d "$_LLAMA_CPP_PARENT" ]; then
-        _CANON_LLAMA_CPP_DIR="$(CDPATH= cd -P -- "$_LLAMA_CPP_PARENT" && pwd -P)/$(basename "$LLAMA_CPP_DIR")"
+        # Nothing can be written under a parent we cannot search, so report here
+        # rather than let the link below abort raw a few lines later.
+        if _canon_parent="$(CDPATH= cd -P -- "$_LLAMA_CPP_PARENT" 2>/dev/null && pwd -P)"; then
+            _CANON_LLAMA_CPP_DIR="$_canon_parent/$(basename "$LLAMA_CPP_DIR")"
+        else
+            _path_access_denied "$_LLAMA_CPP_PARENT" "Unsloth install directory" owner-unverified
+        fi
     fi
     if [ "$_RESOLVED_LOCAL" = "$_CANON_LLAMA_CPP_DIR" ]; then
         # Points at the canonical install location itself: never delete-then-link

tests/sh/test_setup_sh_denied_install_tree.sh

@@ -26,10 +26,9 @@ echo "=== setup.sh: the guards exist and probe the right permission ==="
 
 assert_contains "defines the unsearchable-directory probe" \
     "$SETUP_SH" "_studio_dir_unsearchable() {"
-# cd needs +x, exactly what the marker probes need; ls needs +r, which is neither
-# sufficient nor necessary. Pin the cd form.
+# cd needs +x, what the marker probes need; ls needs +r, neither sufficient nor necessary. Pin the cd form.
 assert_contains "the probe tests search (cd), not read (ls)" \
-    "$SETUP_SH" '( cd "$1" ) 2>/dev/null && return 1'
+    "$SETUP_SH" '( cd -- "$1" ) 2>/dev/null && return 1'
 assert_contains "defines the denial reporter" \
     "$SETUP_SH" "_path_access_denied() {"
 assert_contains "the ownership guard checks readability before blaming ownership" \
@@ -111,6 +110,25 @@ else
     ok "no unguarded rm -rf of the install dir remains"
 fi
 
+# A bare $(cd ...) assignment aborts under errexit before setup_fail can report, leaving
+# an exit code with no [TAURI:ERROR]. Both must sit in an if condition, which errexit exempts.
+if grep -qE '^\s*_RESOLVED_LOCAL="\$\(CDPATH= cd' "$SETUP_SH"; then
+    bad "a denied UNSLOTH_LOCAL_LLAMA_CPP_DIR reports instead of tripping errexit"
+else
+    ok "a denied UNSLOTH_LOCAL_LLAMA_CPP_DIR reports instead of tripping errexit"
+fi
+if grep -qE '^\s*_CANON_LLAMA_CPP_DIR="\$\(CDPATH= cd' "$SETUP_SH"; then
+    bad "an unsearchable install parent is reported instead of aborting"
+else
+    ok "an unsearchable install parent is reported instead of aborting"
+fi
+# Carrying on past a denied parent only moves the abort to the ln a few lines down.
+assert_contains "a denied install parent stops rather than continuing" \
+    "$SETUP_SH" '_path_access_denied "$_LLAMA_CPP_PARENT" "Unsloth install directory" owner-unverified'
+# An unsearchable ancestor makes a real path unstattable, so [ ! -d ] would call it missing.
+assert_contains "a denied ancestor is reported before the missing-path guard" \
+    "$SETUP_SH" '_report_denied_ancestor "$UNSLOTH_LOCAL_LLAMA_CPP_DIR" "UNSLOTH_LOCAL_LLAMA_CPP_DIR"'
+
 echo ""
 echo "=== behaviour against a genuinely unsearchable tree ==="
 
@@ -123,7 +141,8 @@ import sys, pathlib
 src = pathlib.Path(sys.argv[1]).read_text()
 out = []
 for name in ("_studio_owned_adoptable", "_studio_dir_unsearchable",
-             "_studio_dir_unreadable",
+             "_studio_dir_unreadable", "_studio_rstrip_slash",
+             "_report_denied_ancestor",
              "_path_access_denied", "_assert_studio_owned_or_absent"):
     i = src.index(name + "() {")
     out.append(src[i:src.index("\n}\n", i) + 3])
@@ -225,6 +244,113 @@ else
 fi
 chmod 755 "$NOLIST"
 
+# A real build under an unsearchable ancestor must report permissions, not "missing".
+ANC="$WORK/anc"; mkdir -p "$ANC/denied/llama.cpp"
+chmod 000 "$ANC/denied"
+if [ -d "$ANC/denied/llama.cpp" ]; then
+    echo "  SKIP: this host cannot make an ancestor unsearchable (running as root?)"
+else
+    ok "the ancestor is really unsearchable (negative control)"
+    out=$(bash -c '. "$1"
+        C_ERR= C_WARN= C_DIM= C_OK= C_RST=
+        step() { printf "STEP|%s|%s\n" "$1" "$2"; }; substep() { :; }
+        setup_fail() { printf "FAIL|%s\n" "$2"; exit "$1"; }
+        _report_denied_ancestor "$2" "UNSLOTH_LOCAL_LLAMA_CPP_DIR"
+        echo "NOT_REPORTED"' _ "$WORK/helpers.sh" "$ANC/denied/llama.cpp" 2>&1)
+    case "$out" in
+        *"cannot be read: permission denied"*) ok "a build under a denied ancestor reports permissions" ;;
+        *) bad "a build under a denied ancestor reports permissions (got: $out)" ;;
+    esac
+    case "$out" in
+        *"$ANC/denied"*) ok "the message names the denied ancestor, not the leaf" ;;
+        *) bad "the message names the denied ancestor, not the leaf (got: $out)" ;;
+    esac
+fi
+chmod 755 "$ANC/denied"
+# A genuinely missing path must still be reported as missing, not as denied.
+out=$(bash -c '. "$1"
+    C_ERR= C_WARN= C_DIM= C_OK= C_RST=
+    step() { :; }; substep() { :; }
+    setup_fail() { printf "FAIL|%s\n" "$2"; exit "$1"; }
+    _report_denied_ancestor "$2" "UNSLOTH_LOCAL_LLAMA_CPP_DIR"
+    echo "NOT_REPORTED"' _ "$WORK/helpers.sh" "$WORK/definitely-absent" 2>&1)
+case "$out" in
+    *NOT_REPORTED*) ok "a genuinely missing path is not reported as denied" ;;
+    *) bad "a genuinely missing path is not reported as denied (got: $out)" ;;
+esac
+
+# Run the reporter over $2 from directory $1, with errexit on like the real script.
+rda() {
+    ( cd "$1" && bash -c 'set -e
+        . "$1"
+        C_ERR= C_WARN= C_DIM= C_OK= C_RST=
+        step() { printf "STEP|%s|%s\n" "$1" "$2"; }; substep() { :; }
+        setup_fail() { printf "FAIL|%s\n" "$2"; exit "$1"; }
+        _report_denied_ancestor "$2" "UNSLOTH_LOCAL_LLAMA_CPP_DIR"
+        echo "NOT_REPORTED"' _ "$WORK/helpers.sh" "$2" 2>&1 )
+}
+
+# A symlink under a denied ancestor is unstattable all the way down, so a lexical walk alone would call the build missing.
+SYM="$WORK/sym"; mkdir -p "$SYM/shared/denied/build/llama.cpp" "$SYM/tmp"
+ln -s "$SYM/shared/denied/build" "$SYM/tmp/local"
+chmod 000 "$SYM/shared/denied"
+if [ -d "$SYM/tmp/local/llama.cpp" ]; then
+    echo "  SKIP: this host cannot make an ancestor unsearchable (running as root?)"
+else
+    ok "the symlink target is really unreachable (negative control)"
+    out=$(rda "$WORK" "$SYM/tmp/local/llama.cpp")
+    case "$out" in
+        *"$SYM/shared/denied"*) ok "a symlinked build names the denied target ancestor" ;;
+        *) bad "a symlinked build names the denied target ancestor (got: $out)" ;;
+    esac
+fi
+chmod 755 "$SYM/shared/denied"
+
+# A trailing slash follows the link, so "link/" is not -L: it must still report.
+chmod 000 "$SYM/shared/denied"
+if [ -d "$SYM/tmp/local/llama.cpp" ]; then
+    echo "  SKIP: this host cannot make an ancestor unsearchable (running as root?)"
+else
+    case "$(rda "$WORK" "$SYM/tmp/local/")" in
+        *"$SYM/shared/denied"*) ok "a trailing slash still finds the denied target" ;;
+        *) bad "a trailing slash still finds the denied target" ;;
+    esac
+fi
+chmod 755 "$SYM/shared/denied"
+
+# Stripping must stop at the root instead of emptying the path.
+case "$(bash -c '. "$1"; _studio_rstrip_slash "/"; printf "|"; _studio_rstrip_slash "//"' _ "$WORK/helpers.sh")" in
+    "/|/") ok "stripping trailing slashes never consumes the root" ;;
+    *) bad "stripping trailing slashes never consumes the root" ;;
+esac
+
+# A dangling symlink is genuinely missing, so it must not be reported as denied.
+ln -s "$SYM/gone" "$SYM/tmp/dangle"
+case "$(rda "$WORK" "$SYM/tmp/dangle/llama.cpp")" in
+    *NOT_REPORTED*) ok "a dangling symlink is not reported as denied" ;;
+    *) bad "a dangling symlink is not reported as denied" ;;
+esac
+
+# A symlink cycle must terminate on the hop cap instead of looping forever.
+ln -s "$SYM/tmp/a" "$SYM/tmp/b"; ln -s "$SYM/tmp/b" "$SYM/tmp/a"
+case "$(rda "$WORK" "$SYM/tmp/a/llama.cpp")" in
+    *NOT_REPORTED*) ok "a symlink cycle terminates without reporting" ;;
+    *) bad "a symlink cycle terminates without reporting" ;;
+esac
+
+# A leading-dash path must reach the reporter, not be eaten as a dirname option and abort on errexit.
+DASH="$WORK/dash"; mkdir -p "$DASH"
+( cd "$DASH" && mkdir -p -- "-denied/llama.cpp" && chmod 000 -- "-denied" )
+if [ -d "$DASH/-denied/llama.cpp" ]; then
+    echo "  SKIP: this host cannot make an ancestor unsearchable (running as root?)"
+else
+    case "$(rda "$DASH" "-denied/llama.cpp")" in
+        *"cannot be read: permission denied"*) ok "a leading-dash path reports instead of aborting" ;;
+        *) bad "a leading-dash path reports instead of aborting" ;;
+    esac
+fi
+chmod 755 -- "$DASH/-denied"
+
 echo ""
 echo "=== Results ==="
 echo "  PASS: $PASS"