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-- Readers for /proc and /sys.
--
-- Every function takes the file *contents* as a string rather than reading the
-- file itself, so the parsers are testable against fixtures without mocking the
-- filesystem. The thin read-and-parse wrappers live at the bottom.
local M = {}
-- Aggregate CPU jiffies from /proc/stat. Returns total, idle.
-- iowait counts as idle: a core waiting on disk is not doing work, and
-- treating it as busy makes a disk-bound system look CPU-bound.
function M.cpu_times(stat)
local line = stat:match('^cpu%s+([^\n]+)')
if not line then return nil, nil end
local v = {}
for n in line:gmatch('%d+') do v[#v + 1] = tonumber(n) end
if #v < 5 then return nil, nil end
local total = 0
for _, n in ipairs(v) do total = total + n end
return total, v[4] + v[5] -- idle + iowait
end
-- /proc/meminfo, values in kB as the file states them.
function M.mem_info(meminfo)
local function field(name)
return tonumber(meminfo:match(name .. ':%s+(%d+)'))
end
local total = field('MemTotal')
local available = field('MemAvailable')
if not (total and available) then return nil end
return {
total = total,
free = field('MemFree'),
available = available,
-- MemAvailable already excludes reclaimable cache, so this is the figure a
-- user recognises as "used", unlike total-free which counts cache.
used = total - available,
}
end
-- hwmon temp*_input is millidegrees C. Returns whole degrees, or nil.
-- nil rather than 0 on failure: 0 C is a legitimate reading.
function M.millidegrees(s)
if not s then return nil end
local n = tonumber(s:match('^%s*(-?%d+)'))
if not n then return nil end
return math.floor(n / 1000 + 0.5)
end
-- Read a whole file, returning nil if it cannot be read. Used by the wrappers
-- so a vanished sysfs path degrades to nil instead of raising.
function M.slurp(path)
local f = io.open(path, 'r')
if not f then return nil end
local s = f:read('*a')
f:close()
return s
end
-- Find a hwmon directory by the exact contents of its `name` file.
--
-- Globbing by name, never by a fixed hwmon index: indices drift across kernel
-- and hardware reorders, and a stale index silently reports a different chip.
-- Carried over from the previous conky config, where this was the hard-won bit.
function M.hwmon_dir(name)
local p = io.popen('grep -lx ' .. ("%q"):format(name)
.. ' /sys/class/hwmon/hwmon*/name 2>/dev/null')
if not p then return nil end
local hit = p:read('*l')
p:close()
if not hit then return nil end
return hit:match('^(.*)/name$')
end
-- A stateful CPU-load counter.
--
-- Load is work done between two samples, so a single reading cannot produce a
-- percentage. Each counter keeps its own previous sample, which also means a
-- per-core counter is just another instance.
function M.new_cpu_counter()
return {
prev_total = nil,
prev_idle = nil,
-- Returns busy percent since the previous sample, or nil when there is no
-- usable delta (first call, or the counters did not advance).
sample = function(self, total, idle)
if not (total and idle) then return nil end
local pt, pi = self.prev_total, self.prev_idle
self.prev_total, self.prev_idle = total, idle
if not pt then return nil end
local dt = total - pt
if dt <= 0 then return nil end
local busy = (dt - (idle - pi)) / dt * 100
-- Clamp: a counter reset or a suspend/resume can produce a nonsense
-- delta, and a bar drawn at -12% or 340% is worse than a clamped one.
if busy < 0 then busy = 0 elseif busy > 100 then busy = 100 end
return busy
end,
}
end
return M
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