contrib: add a lua module allowing to display cdba board status with conky

contrib/cdba.lua

@@ -0,0 +1,238 @@
+-- SPDX-License-Identifier: BSD-3-Clause
+-- SPDX-FileCopyrightText: 2026 Qualcomm Technologies, Inc. and/or its subsidiaries
+
+local yaml = require("lyaml")
+local stat = require("posix.sys.stat")
+local unistd = require("posix.unistd")
+local pwd = require("posix.pwd")
+
+local function read_cdba_cfg()
+    local pw = pwd.getpwnam("cdba")
+    if not pw then
+        return nil
+    end
+
+    local fd = io.open(pw.pw_dir .. "/.cdba", "r")
+    if not fd then
+        fd = io.open("/etc/cdba", "r")
+	if not fd then
+            return nil
+	end
+    end
+
+    local data = fd:read("*a")
+    fd:close()
+
+    return yaml.load(data)
+end
+
+local cdba_cfg = read_cdba_cfg()
+
+local function file_exists(path)
+    local fd = io.open(path, "r")
+    if fd then
+        fd:close()
+        return true
+    end
+
+    return false
+end
+
+local function stat_file(path)
+    local st, err = stat.stat(path)
+    if not st then
+        return nil, ("stat failed for '%s': %s"):format(path, err)
+    end
+
+    return st
+end
+
+local function dev_major(dev)
+    local hi = math.floor(dev / 2 ^ 32)
+
+    return (math.floor(dev / 2 ^ 8) % 2 ^ 12) + (hi - hi % 2 ^ 12)
+end
+
+local function dev_minor(dev)
+    local mid = math.floor(dev / 2 ^ 12)
+
+    return (dev % 2 ^ 8) + (mid - mid % 2 ^ 8)
+end
+
+local function parse_proc_locks()
+    local fd, err = io.open("/proc/locks", "r")
+    if not fd then
+        return nil, err
+    end
+
+    local records = {}
+
+    for line in fd:lines() do
+        local id, kind, mode, ltype, pid, maj, min, ino, first, last = line:match(
+            "^(%d+):%s+(%S+)%s+(%S+)%s+(%S+)%s+(%-?%d+)%s+(%x+):(%x+):(%d+)%s+(%d+)%s+(%S+)$"
+        )
+
+        if id then
+            records[#records + 1] = {
+                id = tonumber(id),
+                kind = kind,
+                mode = mode,
+                type = ltype,
+                pid = tonumber(pid),
+                major = tonumber(maj, 16),
+                minor = tonumber(min, 16),
+                inode = tonumber(ino),
+                start = tonumber(first),
+                ["end"] = last,
+            }
+        end
+    end
+
+    fd:close()
+    return records
+end
+
+local function match_lock(locks, st)
+    local dev = st.st_dev
+    local inode = st.st_ino
+
+    local major = dev_major(dev)
+    local minor = dev_minor(dev)
+
+    for _, lock in ipairs(locks) do
+        if lock.major == major and lock.minor == minor and lock.inode == inode then
+            return lock
+         end
+    end
+
+    return nil
+end
+
+local function uptime()
+    local fd, err = io.open("/proc/uptime", "r")
+    if not fd then
+        return nil, err
+    end
+
+    local line = fd:read("*l")
+    fd:close()
+
+    local up = line and line:match("^(%S+)")
+    if not up then
+        return nil, "unexpected /proc/uptime format"
+    end
+
+    return tonumber(up)
+end
+
+local function proc_starttime(pid)
+    local fd, err = io.open("/proc/" .. pid .. "/stat", "r")
+    if not fd then
+        return nil, err
+    end
+
+    local line = fd:read("*l")
+    fd:close()
+    if not line then
+        return nil, "empty proc stat entry"
+    end
+
+    local after_comm = line:match(".*%)%s*(.*)$")
+    if not after_comm then
+        return nil, "unexpected proc stat format"
+    end
+
+    local fields = {}
+    for tok in after_comm:gmatch("%S+") do
+        fields[#fields + 1] = tok
+    end
+
+    local starttime = fields[22 - 2]
+    if not starttime then
+        return nil, "starttime missing in proc stat entry"
+    end
+
+    return tonumber(starttime)
+end
+
+local function sec_since_started(lock)
+    local ticks, err = proc_starttime(lock.pid)
+    if not ticks then
+        return nil, err
+    end
+
+    local up, err = uptime()
+    if not up then
+        return nil, err
+    end
+
+    return math.floor(up - (ticks / unistd.sysconf(unistd._SC_CLK_TCK)))
+end
+
+local function cdba_dev_status(dev)
+    local locks, err = parse_proc_locks()
+    if not locks then
+        return "ERROR: " .. err
+    end
+
+    local path = "/tmp/cdba-" .. dev.board .. ".lock"
+    local state = "idle"
+
+    if file_exists(path) then
+        local st, err = stat_file(path)
+        if not st then
+            return "ERROR: " .. err
+        end
+
+        local lock = match_lock(locks, st)
+        if lock then
+            local sec, err = sec_since_started(lock)
+            if not sec then
+                return "ERROR: " .. err
+            end
+
+            state = string.format("running (%ds)", sec)
+        end
+    end
+
+    return string.format("%-20s%s", dev.name .. ":", state)
+end
+
+--- Conky-facing entry point for rendering cdba device info.
+--
+-- Called as ${lua cdba <index> <field>} from conky.config, once per field per
+-- device, with index counting up from 1. Returns "" if index exceeds the
+-- number of devices configured in ~/.cdba, which conky templates use as the
+-- sentinel to stop rendering further rows.
+--
+-- @param index 1-based device index, as a string or number
+-- @param field one of "name", "board", or "status"
+-- @return the requested field value or "" after the last device, or an
+-- "ERROR: ..." string on invalid input
+function conky_cdba(index, field)
+    local idx = tonumber(index)
+
+    if not cdba_cfg then
+        return "ERROR: failed to load the cdba config"
+    end
+
+    if not idx or idx < 1 then
+        return "ERROR: invalid index value: " .. tostring(index)
+    end
+
+    if idx > #cdba_cfg.devices then
+        return ""
+    end
+
+    local dev = cdba_cfg.devices[idx]
+
+    if field == "name" then
+        return dev.name
+    elseif field == "board" then
+        return dev.board
+    elseif field == "status" then
+        return cdba_dev_status(dev)
+    end
+
+    return "ERROR: invalid field name: '" .. field .. "'"
+end