--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/third_party/tectonic/runtime.bzl	Mon Aug 03 20:20:06 2026 -0700
@@ -0,0 +1,62 @@
+def _tectonic_runtime_impl(ctx):
+    output = ctx.actions.declare_directory(ctx.label.name)
+    commands = [
+        "set -e",
+        "mkdir -p {}/bin {}/cache {}/sysroot/etc/fonts {}/sysroot/usr/share/fontconfig/conf.avail".format(
+            output.path,
+            output.path,
+            output.path,
+            output.path,
+        ),
+        "cp {} {}/bin/tectonic".format(ctx.file.binary.path, output.path),
+        "cp {} {}/sysroot/etc/fonts/fonts.conf".format(
+            ctx.file.fontconfig.path,
+            output.path,
+        ),
+        "cp {} {}/LICENSE".format(ctx.file.license.path, output.path),
+        "cp {} {}/THIRD_PARTY_NOTICES.md".format(
+            ctx.file.notices.path,
+            output.path,
+        ),
+        "tar -xzf {} -C {}/cache".format(
+            ctx.file.cache_archive.path,
+            output.path,
+        ),
+        "chmod 0555 {}/bin/tectonic".format(output.path),
+        "chmod 0444 {}/sysroot/etc/fonts/fonts.conf".format(output.path),
+        "chmod 0444 {}/LICENSE {}/THIRD_PARTY_NOTICES.md".format(
+            output.path,
+            output.path,
+        ),
+    ]
+    commands.append("chmod -R a-w {}/cache".format(output.path))
+
+    ctx.actions.run_shell(
+        inputs = [
+            ctx.file.binary,
+            ctx.file.cache_archive,
+            ctx.file.fontconfig,
+            ctx.file.license,
+            ctx.file.notices,
+        ],
+        outputs = [output],
+        command = "\n".join(commands),
+        progress_message = "Assembling offline Tectonic runtime",
+    )
+    return [
+        DefaultInfo(
+            files = depset([output]),
+            runfiles = ctx.runfiles(files = [output]),
+        ),
+    ]
+
+tectonic_runtime = rule(
+    implementation = _tectonic_runtime_impl,
+    attrs = {
+        "binary": attr.label(allow_single_file = True, mandatory = True),
+        "cache_archive": attr.label(allow_single_file = True, mandatory = True),
+        "fontconfig": attr.label(allow_single_file = True, mandatory = True),
+        "license": attr.label(allow_single_file = True, mandatory = True),
+        "notices": attr.label(allow_single_file = True, mandatory = True),
+    },
+)