bcc: Allow the runner to parse some arguments

src/lua/bcc/libbcc.lua

@@ -98,4 +98,4 @@ int perf_reader_fd(struct perf_reader *reader);
 void perf_reader_set_fd(struct perf_reader *reader, int fd);
 ]]
 
-return ffi.load(rawget(_G, "LIBBCC_SO_PATH") or "bcc")
+return ffi.load(os.getenv("LIBBCC_SO_PATH") or rawget(_G, "LIBBCC_SO_PATH") or "bcc")

src/lua/bcc/run.lua

@@ -14,19 +14,58 @@ 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
+
+ while arg[1] and has_prefix(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 k == "-q" or k == "--quiet" then
+ logging = 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
+ else
+ print_usage()
+ end
+ end
+
+ local tracefile = table.remove(arg, 1)
+ if not tracefile then print_usage() end
+
  local BCC = require("bcc.init")
  local BPF = BCC.BPF
 
- BPF.script_root(arg[1])
+ BPF.script_root(tracefile)
+ log.enabled = logging
 
  local utils = {
  argparse = require("bcc.vendor.argparse"),
  posix = require("bcc.vendor.posix"),
  sym = BCC.sym
  }
 
- local tracefile = table.remove(arg, 1)
  local command = dofile(tracefile)
  local res, err = pcall(command, BPF, utils)