Checks thumbnailers for conflicting or incorrect setup

check-thumbnailers.sh

#!/usr/bin/env bash
# check-thumbnailers.sh — diagnose thumbnail generation issues
# Checks: MIME conflicts, broken binaries, missing libs, cache state, env vars, sandbox

set -uo pipefail

THUMBNAILER_DIR="${THUMBNAILER_DIR:-/usr/share/thumbnailers}"
THUMB_CACHE="${XDG_CACHE_HOME:-$HOME/.cache}/thumbnails"

RED='\033[0;31m'; YELLOW='\033[1;33m'; GREEN='\033[0;32m'; BOLD='\033[1m'; RESET='\033[0m'

ok()   { echo -e "  ${GREEN}✓${RESET} $*"; }
warn() { echo -e "  ${YELLOW}⚠${RESET}  $*"; }
fail() { echo -e "  ${RED}✗${RESET} $*"; }
section() { echo -e "\n${BOLD}── $* ──${RESET}"; }

# ── 1. Parse all thumbnailers ────────────────────────────────────────────────
section "Thumbnailer files ($THUMBNAILER_DIR)"

declare -A mime_to_thumbnailers   # mime → "file1:file2:..." (in readdir order)
declare -A thumbnailer_exec       # file → Exec line
declare -A thumbnailer_tryexec    # file → TryExec binary

# Read files in inode (readdir) order — this matches how gnome-desktop loads them
# Last entry for a given MIME type wins (g_hash_table_replace behaviour)
mapfile -t TFILES < <(ls -i "$THUMBNAILER_DIR"/*.thumbnailer 2>/dev/null \
    | sort -n | awk '{print $2}')

if [[ ${#TFILES[@]} -eq 0 ]]; then
    fail "No thumbnailer files found in $THUMBNAILER_DIR"
    exit 1
fi

for tfile in "${TFILES[@]}"; do
    name=$(basename "$tfile")
    exec_line=$(grep -m1 '^Exec=' "$tfile" | cut -d= -f2- || true)
    tryexec=$(grep -m1 '^TryExec=' "$tfile" | cut -d= -f2- || true)
    mimetypes=$(grep -m1 '^MimeType=' "$tfile" | cut -d= -f2- | tr ';' '\n' | grep -v '^$' || true)

    thumbnailer_exec["$name"]="$exec_line"
    thumbnailer_tryexec["$name"]="${tryexec:-}"

    echo "  $name"
    while IFS= read -r mime; do
        [[ -z "$mime" ]] && continue
        if [[ -v mime_to_thumbnailers["$mime"] ]]; then
            mime_to_thumbnailers["$mime"]+=" $name"
        else
            mime_to_thumbnailers["$mime"]="$name"
        fi
    done <<< "$mimetypes"
done

# ── 2. MIME type conflicts ───────────────────────────────────────────────────
section "MIME type conflicts (last loaded wins)"

conflicts=0
for mime in $(echo "${!mime_to_thumbnailers[@]}" | tr ' ' '\n' | sort); do
    entries="${mime_to_thumbnailers[$mime]}"
    count=$(echo "$entries" | wc -w)
    if [[ $count -gt 1 ]]; then
        winner=$(echo "$entries" | awk '{print $NF}')
        losers=$(echo "$entries" | awk 'NF>1{for(i=1;i<NF;i++) printf $i" "; print ""}' | sed 's/ $//')
        warn "$mime"
        echo "       winner : $winner"
        echo "       ignored: $losers"
        conflicts=$((conflicts + 1))
    fi
done
[[ $conflicts -eq 0 ]] && ok "No conflicts"

# ── 3. Binary checks ─────────────────────────────────────────────────────────
section "Thumbnailer binary checks"

for name in "${!thumbnailer_tryexec[@]}"; do
    tryexec="${thumbnailer_tryexec[$name]}"
    if [[ -z "$tryexec" ]]; then
        warn "$name: no TryExec defined"
        continue
    fi

    binary=$(command -v "$tryexec" 2>/dev/null || echo "")
    if [[ -z "$binary" ]]; then
        fail "$name: binary not found: $tryexec"
        continue
    fi

    # Check for missing shared libraries
    missing=$(ldd "$binary" 2>/dev/null | grep "not found" || true)
    if [[ -n "$missing" ]]; then
        fail "$name ($binary): missing libraries:"
        echo "$missing" | sed 's/^/         /'
    else
        ok "$name: $binary (libs ok)"
    fi
done

# ── 4. Effective thumbnailer per MIME (what Nautilus/Nemo actually uses) ─────
section "Effective thumbnailer per MIME type"

declare -A winner_for_mime
for mime in $(echo "${!mime_to_thumbnailers[@]}" | tr ' ' '\n' | sort); do
    entries="${mime_to_thumbnailers[$mime]}"
    winner=$(echo "$entries" | awk '{print $NF}')
    winner_for_mime["$mime"]="$winner"
done

# Group by winner for compact output
declare -A winner_mimes
for mime in "${!winner_for_mime[@]}"; do
    w="${winner_for_mime[$mime]}"
    winner_mimes["$w"]+="$mime "
done

for w in $(echo "${!winner_mimes[@]}" | tr ' ' '\n' | sort); do
    tryexec="${thumbnailer_tryexec[$w]:-unknown}"
    binary=$(command -v "$tryexec" 2>/dev/null || echo "MISSING")
    missing_libs=$(ldd "$binary" 2>/dev/null | grep -c "not found" || true)
    missing_libs="${missing_libs:-0}"

    if [[ "$binary" == "MISSING" ]]; then
        status="${RED}BROKEN (binary missing)${RESET}"
    elif [[ "$missing_libs" -gt 0 ]]; then
        status="${RED}BROKEN ($missing_libs missing libs)${RESET}"
    else
        status="${GREEN}ok${RESET}"
    fi

    echo -e "  ${BOLD}$w${RESET} [${status}]"
    echo "${winner_mimes[$w]}" | tr ' ' '\n' | grep -v '^$' | sort | sed 's/^/    /'
done

# ── 5. Thumbnail cache state ──────────────────────────────────────────────────
section "Thumbnail cache ($THUMB_CACHE)"

total_normal=$(find "$THUMB_CACHE" -name "*.png" ! -path "*/fail/*" 2>/dev/null | wc -l)
ok "$total_normal normal thumbnails cached"

for fail_dir in "$THUMB_CACHE"/fail/*/; do
    [[ -d "$fail_dir" ]] || continue
    count=$(find "$fail_dir" -name "*.png" 2>/dev/null | wc -l)
    dname=$(basename "$fail_dir")
    if [[ $count -gt 0 ]]; then
        warn "$count fail entries in $dname"
        # Sample a few URIs
        mapfile -t samples < <(find "$fail_dir" -name "*.png" 2>/dev/null | head -3)
        for f in "${samples[@]}"; do
            uri=$(exiftool -s3 -ThumbURI "$f" 2>/dev/null || true)
            [[ -n "$uri" ]] && echo "       e.g. $uri"
        done
    else
        ok "fail/$dname is empty"
    fi
done

# ── 6. Stale temp dirs ────────────────────────────────────────────────────────
section "Stale thumbnailer temp dirs (/tmp)"

stale=0
for pattern in gnome-desktop-thumbnailer nemo-thumbnail; do
    dirs=$(find /tmp -maxdepth 1 -name "${pattern}*" -type d 2>/dev/null | wc -l)
    if [[ $dirs -gt 0 ]]; then
        warn "$dirs stale /tmp/${pattern}* dirs (thumbnailer left files behind)"
        mapfile -t sample < <(find /tmp -maxdepth 1 -name "${pattern}*" -type d 2>/dev/null | head -3)
        for d in "${sample[@]}"; do
            contents=$(ls "$d" 2>/dev/null | tr '\n' ' ')
            echo "       $d: $contents"
        done
        stale=$((stale + dirs))
    fi
done
[[ $stale -eq 0 ]] && ok "No stale temp dirs"

# ── 7. Environment variables ──────────────────────────────────────────────────
section "Environment"

check_env() {
    local var="$1"
    local src="$2"
    local val
    val=$(eval "echo \${$var:-}")
    if [[ -n "$val" ]]; then
        ok "$var=$val (in $src)"
    else
        echo "  - $var: not set (in $src)"
    fi
}

# Current shell
check_env GLYCIN_DISABLE_SANDBOX "shell"

# Systemd user session
sd_val=$(systemctl --user show-environment 2>/dev/null | grep "^GLYCIN_DISABLE_SANDBOX=" | cut -d= -f2- || true)
if [[ -n "$sd_val" ]]; then
    ok "GLYCIN_DISABLE_SANDBOX=$sd_val (systemd user session)"
else
    echo "  - GLYCIN_DISABLE_SANDBOX: not in systemd user session"
fi

# environment.d files
env_d_dirs=("$HOME/.config/environment.d" "/etc/environment.d")
for d in "${env_d_dirs[@]}"; do
    if [[ -d "$d" ]]; then
        found=$(grep -r "GLYCIN_DISABLE_SANDBOX" "$d" 2>/dev/null || true)
        if [[ -n "$found" ]]; then
            ok "GLYCIN_DISABLE_SANDBOX found in $d"
        fi
    fi
done

# Running file manager processes
for fm in nautilus nemo thunar; do
    pid=$(pgrep -x "$fm" 2>/dev/null | head -1 || true)
    if [[ -n "$pid" ]]; then
        val=$(tr '\0' '\n' < "/proc/$pid/environ" 2>/dev/null | grep "^GLYCIN_DISABLE_SANDBOX=" | cut -d= -f2- || true)
        if [[ -n "$val" ]]; then
            ok "$fm (pid $pid): GLYCIN_DISABLE_SANDBOX=$val"
        else
            warn "$fm (pid $pid): GLYCIN_DISABLE_SANDBOX not in process environment"
        fi
    fi
done

# ── 8. Sandbox / bwrap ───────────────────────────────────────────────────────
section "Sandbox (bwrap)"

if command -v bwrap &>/dev/null; then
    bwrap_out=$(bwrap --unshare-user --ro-bind /usr /usr \
        --symlink /usr/lib /lib --symlink /usr/lib /lib64 \
        /usr/bin/true 2>&1); bwrap_ok=$?
    if [[ $bwrap_ok -eq 0 ]]; then
        ok "bwrap user namespaces work"
    else
        warn "bwrap user namespaces fail: $bwrap_out"
        echo "  → glycin sandbox will fall back (expect 'WARNING: Glycin running without sandbox')"
    fi

    unprivileged=$(cat /proc/sys/kernel/unprivileged_userns_clone 2>/dev/null \
        || cat /proc/sys/user/max_user_namespaces 2>/dev/null || echo "unknown")
    echo "  unprivileged_userns_clone / max_user_namespaces: $unprivileged"
else
    fail "bwrap not found — glycin sandbox unavailable"
fi

# ── 9. Quick thumbnailer smoke test ──────────────────────────────────────────
if [[ -n "${1:-}" && -f "$1" ]]; then
    section "Smoke test: $1"
    mime=$(file --mime-type -b "$1")
    echo "  MIME: $mime"
    effective="${winner_for_mime[$mime]:-none}"
    echo "  Effective thumbnailer: $effective"

    if [[ "$effective" != "none" ]]; then
        tryexec="${thumbnailer_tryexec[$effective]:-}"
        exec_tmpl="${thumbnailer_exec[$effective]:-}"
        outfile=$(mktemp /tmp/thumb-test-XXXXXX.png)
        cmd="${exec_tmpl//%u/file:\/\/$(realpath "$1")}"
        cmd="${cmd//%i/file:\/\/$(realpath "$1")}"
        cmd="${cmd//%o/$outfile}"
        cmd="${cmd//%s/256}"

        echo "  Running: $cmd"
        if eval "$cmd" 2>&1; then
            if [[ -s "$outfile" ]]; then
                ok "Thumbnail created: $outfile ($(du -h "$outfile" | cut -f1))"
            else
                fail "Thumbnailer exited 0 but produced no output"
                rm -f "$outfile"
            fi
        else
            fail "Thumbnailer exited non-zero"
            rm -f "$outfile"
        fi
    fi
fi

echo -e "\n${BOLD}Done.${RESET}"
echo "Tip: to clear fail cache: rm -rf $THUMB_CACHE/fail/gnome-thumbnail-factory/"
echo "     to clear stale temp:  rm -rf /tmp/gnome-desktop-thumbnailer-*"