fix systrack synchronization

* change luaprobe to sleep=false
* split systrack into two runtimes (driver and probes)

Author: lneto

Makefile

@@ -54,6 +54,8 @@ examples_install:
 	${INSTALL} -m 0644 examples/dnsblock/*.lua ${SCRIPTS_INSTALL_PATH}/examples/dnsblock
 	${MKDIR} ${SCRIPTS_INSTALL_PATH}/examples/dnsdoctor
 	${INSTALL} -m 0644 examples/dnsdoctor/*.lua ${SCRIPTS_INSTALL_PATH}/examples/dnsdoctor
+	${MKDIR} ${SCRIPTS_INSTALL_PATH}/examples/systrack
+	${INSTALL} -m 0644 examples/systrack/*.lua ${SCRIPTS_INSTALL_PATH}/examples/systrack
 
 examples_uninstall:
 	${RM} -r ${SCRIPTS_INSTALL_PATH}/examples

README.md

@@ -1469,8 +1469,7 @@ hello kernel!
 
 [systrack](examples/systrack.lua)
 is a kernel script that implements a device driver to monitor system calls.
-It prints the amount of times each [system call](examples/systrack.lua#L29)
-was called since the driver has been installed.
+It prints the amount of times each system call was called since the driver has been installed.
 
 #### Usage
 
@@ -1484,6 +1483,7 @@ write: 1085
 openat: 2036
 read: 4131
 readv: 0
+...
 ```
 
 ### filter

examples/systrack.lua

@@ -3,41 +3,32 @@
 -- SPDX-License-Identifier: MIT OR GPL-2.0-only
 --
 
-local linux  = require("linux")
-local probe  = require("probe")
-local device = require("device")
-local systab = require("syscall.table")
-
-local syscalls = {"openat", "read", "write", "readv", "writev", "close"}
+local lunatik = require("lunatik")
+local runner  = require("lunatik.runner")
+local linux   = require("linux")
+local device  = require("device")
+local rcu     = require("rcu")
 
 local function nop() end -- do nothing
 
 local s = linux.stat
 local driver = {name = "systrack", open = nop, release = nop, mode = s.IRUGO}
 
-local track = {}
+local systrack = rcu.table()
+lunatik._ENV.systrack = systrack
+
 local toggle = true
 function driver:read()
 	local log = ""
 	if toggle then
-		for symbol, counter in pairs(track) do
-			log = log .. string.format("%s: %d\n", symbol, counter)
-		end
+		rcu.map(systrack, function (symbol, counter)
+			log = log .. string.format("%s: %d\n", symbol, counter:getnumber(0))
+		end)
 	end
 	toggle = not toggle
 	return log
 end
 
-for _, symbol in ipairs(syscalls) do
-	local address = systab[symbol]
-	track[symbol] = 0
-
-	local function handler()
-		track[symbol] = track[symbol] + 1
-	end
-
-	probe.new(address, {pre = handler, post = nop})
-end
-
+runner.run("examples/systrack/probes", false)
 device.new(driver)
 

examples/systrack/probes.lua

@@ -0,0 +1,30 @@
+--
+-- SPDX-FileCopyrightText: (c) 2023-2024 Ring Zero Desenvolvimento de Software LTDA
+-- SPDX-License-Identifier: MIT OR GPL-2.0-only
+--
+
+local lunatik = require("lunatik")
+local probe   = require("probe")
+local syscall = require("syscall.table")
+local data    = require("data")
+
+local systrack = lunatik._ENV.systrack
+
+local function nop() end -- do nothing
+
+local function inc(counter)
+	counter:setnumber(0, counter:getnumber(0) + 1)
+end
+
+local sizeofnumber = string.packsize("n")
+
+for symbol, address in pairs(syscall) do
+	systrack[symbol] = data.new(sizeofnumber)
+
+	local function handler()
+		inc(systrack[symbol])
+	end
+
+	probe.new(address, {pre = handler, post = nop})
+end
+

lib/luaprobe.c

@@ -167,7 +167,7 @@ static const lunatik_class_t luaprobe_class = {
 	.name = "probe",
 	.methods = luaprobe_mt,
 	.release = luaprobe_release,
-	.sleep = true,
+	.sleep = false,
 };
 
 static int luaprobe_new(lua_State *L)