added library for pidof

git-svn-id: svn://svn.alpinelinux.org/acf/core/trunk@329 ab2d0c66-481e-0410-8bed-d214d4d58bed

2 files changed, 72 insertions, 0 deletions

diff --git a/lib/Makefile b/lib/Makefile
index d444f24..5fa957c 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -5,6 +5,7 @@ LIB_DIST=fs.lua\
 	join.lua\
 	log_view.lua\
 	menubuilder.lua\
+	pidof.lua\
 	privsep.lua\
 	service_controller.lua\
 	service_model.lua\
diff --git a/lib/pidof.lua b/lib/pidof.lua
new file mode 100644
index 0000000..d05ee14
--- /dev/null
+++ b/lib/pidof.lua
@@ -0,0 +1,71 @@
+
+module(..., package.seeall)
+
+require("posix")
+
+-- the following methods are available:
+-- /proc/<pid>/stat	the comm field (2nd) field contains name but only up 
+--   			to 15 chars. does not resolve links
+--
+-- /proc/<pid>/cmdline	argv[0] contains the command. However if it is a script
+--   			then will the interpreter show up
+--
+-- /proc/<pid>/exe	link to exe file. this will resolv links
+--
+-- returns list of all pids for given exe name
+
+--[[
+-- gives lots of false positives for busybox
+local function is_exe(path, name)
+	local f = posix.readlink(path.."/exe")
+	if f and (f == name or posix.basename(f) == name) then
+		return true
+	else
+		return false
+	end
+end
+]]--
+
+
+local function is_stat(path, name)
+	local f = io.open(path.."/stat")
+	local line = f:read()
+	local p = string.match(line, "^%d+ %((%d+)%)")
+	f:close()
+	if p ~= nil and string.len(name) <= 15 and p == name then
+		return true
+	else
+		return false
+	end
+end
+
+local function is_cmdline(path, name)
+	local f = io.open(path.."/cmdline")
+	if f == nil then
+		return false
+	end
+	local line = f:read()
+	f:close()
+	if line == nil then 
+		return false
+	end
+	local arg0 = string.gsub(line, string.char(0)..".*", "")
+	return posix.basename(arg0) == name
+end
+
+function pidof(name)
+	local pids = {}
+	local i, j
+
+	for i,j in pairs(posix.glob("/proc/[0-9]*")) do
+		local pid = tonumber(posix.basename(j))
+		if is_stat(j, name) or is_cmdline(j, name) then
+			table.insert(pids, pid)
+		end
+	end
+	if #pids == 0 then
+		pids = nil
+	end
+	return pids
+end
+