bcc: Move all `argv` parsing to Lua code

src/lua/bcc-probe

@@ -17,5 +17,5 @@ limitations under the License.
 local str = require("debug").getinfo(1, "S").source:sub(2)
 local script_path = str:match("(.*/)").."/?.lua;"
 package.path = script_path..package.path
-rawset(_G, "BCC_STANDALONE", false)
+rawset(_G, "BCC_STANDALONE_NAME", "bcc-probe")
 require("bcc.run")()

src/lua/bcc/run.lua

@@ -14,38 +14,37 @@ See the License for the specific language governing permissions and
 limitations under the License.
 ]]
 
-local function print_usage()
-  io.stderr:write(
-  "usage: bcc-probe [[--so-path=PATH|--version|--quiet] --] path_to_script.lua [...]\n")
-  os.exit(1)
-end
-
-local function has_prefix(s,p)
-  return string.sub(s,1,string.len(p))==p
-end
-
-local function strip_prefix(s,p)
-  return string.sub(s, string.len(p) + 1)
-end
-
 return function()
-  local logging = true
+  require("bcc.vendor.helpers")
+  local progname = rawget(_G, "BCC_STANDALONE_NAME") or "bcc-lua"
+
+  local function print_usage()
+    io.stderr:write(string.format(
+      "usage: %s [[--so-path=PATH|--version|--quiet] --] path_to_script.lua [...]\n",
+      progname))
+    os.exit(1)
+  end
 
-  while arg[1] and has_prefix(arg[1], "-") do
-    local k = table.remove(arg, 1) 
+  local function print_version()
+    local jit = require("jit")
+    print(string.format("%s %s -- Running on %s (%s/%s)",
+      progname, rawget(_G, "BCC_VERSION") or "HEAD",
+      jit.version, jit.os, jit.arch))
+    os.exit(0)
+  end
 
+  while arg[1] and string.starts(arg[1], "-") do
+    local k = table.remove(arg, 1)
     if k == "--" then
       break
-    elseif has_prefix(k, "--so-path=") then
-      rawset(_G, "LIBBCC_SO_PATH", strip_prefix(k, "--so-path="))
+    elseif string.starts(k, "--so-path=") then
+      rawset(_G, "LIBBCC_SO_PATH", string.lstrip(k, "--so-path="))
+    elseif k == "--llvm-debug" then
+      rawset(_G, "LIBBCC_LLVM_DEBUG", 1)
     elseif k == "-q" or k == "--quiet" then
-      logging = false
+      log.enabled = false
     elseif k == "-v" or k == "--version" then
-      local jit = require("jit")
-      print(string.format("bcc-probe %s -- Running on %s (%s/%s)",
-        rawget(_G, "BCC_VERSION") or "HEAD",
-        jit.version, jit.os, jit.arch))
-      return true
+      print_version()
     else
       print_usage()
     end
@@ -54,16 +53,13 @@ return function()
   local tracefile = table.remove(arg, 1)
   if not tracefile then print_usage() end
 
-  local BCC = require("bcc.init")
-  local BPF = BCC.BPF
-
+  local BPF = require("bcc.bpf")
   BPF.script_root(tracefile)
-  log.enabled = logging
 
   local utils = {
     argparse = require("bcc.vendor.argparse"),
     posix = require("bcc.vendor.posix"),
-    sym = BCC.sym
+    sym = require("bcc.sym"),
   }
 
   local command = dofile(tracefile)

src/lua/bcc/vendor/helpers.lua

-function string.starts(String,Start)
-  return string.sub(String,1,string.len(Start))==Start
+function string.starts(s, p)
+  return string.sub(s, 1, string.len(p)) == p
 end
 
-function string.ends(String,End)
-  return End=='' or string.sub(String,-string.len(End))==End
+function string.lstrip(s, p)
+  return string.sub(s, string.len(p) + 1)
+end
+
+function string.ends(s, e)
+  return e == '' or string.sub(s, -string.len(e))==e
 end
 
 function string.escape(s)

src/lua/src/main.c

@@ -125,31 +125,25 @@ static void pushargv(lua_State *L, char **argv, int argc, int offset)
 	}
 }
 
-static int find_libbcc(lua_State *L)
+static void find_local_libbcc(lua_State *L)
 {
-	const char *libbcc = getenv("LIBBCC_SO_PATH");
 	char buffer[4096];
+	char *dirname;
 
-	if (libbcc == NULL) {
-		char *dirname;
+	if (readlink("/proc/self/exe", buffer, sizeof(buffer)) < 0)
+		return;
 
-		if (readlink("/proc/self/exe", buffer, sizeof(buffer)) < 0)
-			return -1;
+	dirname = strrchr(buffer, '/');
+	if (dirname == NULL)
+		return;
 
-		dirname = strrchr(buffer, '/');
-		if (dirname == NULL)
-			return -1;
+	strcpy(dirname + 1, "libbcc.so");
 
-		strcpy(dirname + 1, "libbcc.so");
-		libbcc = buffer;
-	}
-
-	if (access(libbcc, F_OK|R_OK|X_OK) != 0)
-		return -1;
+	if (access(buffer, F_OK|R_OK|X_OK) != 0)
+		return;
 
-	lua_pushstring(L, libbcc);
+	lua_pushstring(L, buffer);
 	lua_setglobal(L, "LIBBCC_SO_PATH");
-	return 0;
 }
 
 static int pmain(lua_State *L)
@@ -160,19 +154,14 @@ static int pmain(lua_State *L)
 	lua_gc(L, LUA_GCSTOP, 0);
 	luaL_openlibs(L);
 	lua_gc(L, LUA_GCRESTART, 0);
-
-	if (find_libbcc(L) < 0) {
-		s->status = 1;
-		l_message(progname, "failed to find libbcc.so");
-		return 0;
-	}
+	find_local_libbcc(L);
 
 	s->status = dolibrary(L, "bcc", 0);
 	if (s->status)
 		return 0;
 
-	lua_pushboolean(L, 1);
-	lua_setglobal(L, "BCC_STANDALONE");
+	lua_pushstring(L, progname);
+	lua_setglobal(L, "BCC_STANDALONE_NAME");
 
 	pushargv(L, s->argv, s->argc, 1);
 	lua_setglobal(L, "arg");
@@ -192,13 +181,7 @@ int main(int argc, char **argv)
 		return EXIT_FAILURE;
 	}
 
-	if (argc < 2) {
-		fprintf(stderr, "usage: %s path_to_probe.lua [...]\n", argv[0]);
-		return EXIT_FAILURE;
-	}
-
 	progname = argv[0];
-
 	s.argc = argc;
 	s.argv = argv;
 	s.status = 0;