more things

configure.py

@@ -5,9 +5,13 @@ usage:
     python3 configure.py
     python3 configure.py --asan      # enable address/undefined sanitizers
     python3 configure.py --debug     # -O0 instead of -O2
+    python3 configure.py --selinux   # enable SELinux integration
+    python3 configure.py --compile-commands  # also write build/compile_commands.json
 """
 import argparse
+import json
 import os
+import shlex
 import shutil
 import sys
 from pathlib import Path
@@ -54,10 +58,19 @@ format:
     )
 
 
-def emit_ninja(cxx, cxxflags, dst):
+def emit_ninja(cxx, cxxflags, dst, write_cc=False):
     sources = discover_sources()
     objs = ["obj/" + Path(s).stem + ".o" for s in sources]
     target = "bajia"
+    ctl_target = "bctl"
+    # bctl_main.cpp is a second shipped binary (the control client),
+    # excluded from the init objects by the *_main.cpp convention.
+    ctl_source = SRC / "bctl_main.cpp"
+    ctl_obj = "obj/bctl_main.o"
+
+    # (source, output) pairs for compile_commands.json.
+    cc_entries = [(SRC / s, o) for s, o in zip(sources, objs)]
+    cc_entries.append((ctl_source, ctl_obj))
 
     rule_cxx = (
         "rule cxx\n"
@@ -77,22 +90,49 @@ def emit_ninja(cxx, cxxflags, dst):
     lines.append(rule_cxx)
     lines.append(rule_link)
     lines.append('build {target}: link {objs}'.format(target=target, objs=" ".join(objs)))
+    lines.append('build {ctl}: link {ctl_obj}'.format(ctl=ctl_target, ctl_obj=ctl_obj))
     lines.append("")
     for o, s in zip(objs, sources):
         lines.append('build {o}: cxx {src}/{s}'.format(o=o, src=SRC, s=s))
+    lines.append('build {ctl_obj}: cxx {ctl_src}'.format(ctl_obj=ctl_obj, ctl_src=ctl_source))
     lines.append("")
-    lines.append('build all: phony {target}'.format(target=target))
+    lines.append(
+        'build all: phony {target} {ctl}'.format(target=target, ctl=ctl_target))
     lines.append("default all")
     lines.append("")
 
+    if write_cc:
+        write_compile_commands(cxx, cxxflags, cc_entries)
+
     (BUILD / "obj").mkdir(exist_ok=True)
     dst.write_text("\n".join(lines) + "\n", encoding="utf-8")
 
+def write_compile_commands(cxx, cxxflags, src_out_pairs):
+    """Write build/compile_commands.json for clangd / clang-tidy."""
+    entries = []
+    for src, out in src_out_pairs:
+        args = [cxx] + list(cxxflags) + ["-c", str(src), "-o", out]
+        entries.append({
+            "directory": str(BUILD.resolve()),
+            "file": str(src.resolve()),
+            "output": out,
+            "arguments": args,
+            "command": shlex.join(args),
+        })
+    (BUILD / "compile_commands.json").write_text(
+        json.dumps(entries, indent=1) + "\n", encoding="utf-8")
+
+
 def parse_args():
     p = argparse.ArgumentParser(description="Configure bajia build (generates build.ninja)")
     p.add_argument("--asan", action="store_true", help="enable address + UB sanitizers")
     p.add_argument("--debug", action="store_true", help="disable -O2, enable -O0")
     p.add_argument("--clean", action="store_true", help="remove build dir")
+    p.add_argument("--selinux", action="store_true",
+                   help="enable SELinux integration (needs libselinux-dev; "
+                        "see tools/run_vm.py --selinux for a VM test path)")
+    p.add_argument("--compile-commands", action="store_true",
+                   help="write build/compile_commands.json (for clangd)")
     return p.parse_args()
 
 def main():
@@ -106,6 +146,20 @@ def main():
         print("error: ninja not found in PATH", file=sys.stderr)
         return 1
 
+    # Wipe stale objects when compiler flags change: ninja doesn't track
+    # cflags, so a re-run with a different --selinux/--asan/--debug profile
+    # would otherwise link a half-stale tree.
+    stamp = {"selinux": args.selinux, "asan": args.asan, "debug": args.debug}
+    stamp_file = BUILD / ".configure.json"
+    if stamp_file.exists():
+        try:
+            prev = json.loads(stamp_file.read_text())
+        except (json.JSONDecodeError, OSError):
+            prev = None
+        if prev != stamp:
+            print("build configuration changed; cleaning build/")
+            shutil.rmtree(BUILD, ignore_errors=True)
+
     BUILD.mkdir(exist_ok=True)
 
     cxxflags = list(CXXFLAGS)
@@ -117,14 +171,20 @@ def main():
     if args.asan:
         cxxflags += ["-fsanitize=address,undefined", "-fno-omit-frame-pointer"]
         linkflags += ["-fsanitize=address,undefined"]
+    if args.selinux:
+        cxxflags += ["-DBAJIA_SELINUX"]
+        linkflags += ["-lselinux"]
 
     cxxflags = [f for f in cxxflags if f not in WARNINGS]
     cxxflags = WARNINGS + cxxflags
 
-    emit_ninja(CXX, cxxflags, BUILD / "build.ninja")
+    emit_ninja(CXX, cxxflags, BUILD / "build.ninja", write_cc=args.compile_commands)
     write_makefile_convenience()
+    stamp_file.write_text(json.dumps(stamp, indent=1) + "\n", encoding="utf-8")
 
     print(f"configured {len(discover_sources())} sources -> build/build.ninja")
+    if args.compile_commands:
+        print("wrote build/compile_commands.json")
     print("run: ninja -C build")
     return 0