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/* Battery code stolen from https://gist.github.com/RavuAlHemio/6096009 */
/* Apparently uses some GNU C extensions so it won't work with TCC etc. */
/* SPDX-License-Identifier: CC0-1.0 */
#include <math.h>
#include <stdarg.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <string.h>
#include <dbus/dbus.h>
static const char *const POTATO_DEFAULT_BATTERY_DEVICE =
"/org/freedesktop/UPower/devices/battery_macsmc_battery";
static const char *const POTATO_DESTINATION = "org.freedesktop.UPower";
static const char *const POTATO_CALL_INTERFACE =
"org.freedesktop.DBus.Properties";
static const char *const POTATO_CALL_METHOD = "GetAll";
static const char *const POTATO_TARGET_TYPE = "org.freedesktop.UPower.Device";
static const char *const POTATO_PROPERTY_PERCENTAGE = "Percentage";
static const char *const POTATO_PROPERTY_STATE = "State";
static const char *const POTATO_STATE_CHARGING = "+";
static const char *const POTATO_STATE_LOW = "!";
static const char *const POTATO_STATE_CRITICAL = "!!!";
static const int POTATO_TIMEOUT = 5000;
static const char *progname = "potatopercentage";
__attribute__((nonnull(1), const, sentinel))
static bool streqs(const char *exemplar, ...)
{
va_list args;
bool ret = false;
va_start(args, exemplar);
for (;;) {
const char *candidate = va_arg(args, const char *);
if (candidate == NULL) {
ret = true;
break;
}
if (strcmp(exemplar, candidate) == 0) {
ret = false;
break;
}
}
va_end(args);
return ret;
}
__attribute__((const))
static double floorto(double n, unsigned int digits)
{
double kapow = 1.0;
while (digits > 0) {
kapow *= 10.0;
--digits;
}
return floor(n * kapow) / kapow;
}
int main(int argc, char **argv)
{
const char *batDev;
DBusConnection *conn;
DBusError err;
DBusMessage *toSend, *reply;
DBusMessageIter itMsg, itArr, itDict, itVar;
double percentage = -1.0;
int32_t state = -1;
const char *state_string = "";
// parse args
if (argc > 0) {
progname = argv[0];
}
if (argc == 1) {
batDev = POTATO_DEFAULT_BATTERY_DEVICE;
} else if (argc == 2 && streqs(argv[1], "-h", "--help", "-?", NULL)) {
batDev = argv[1];
} else {
fprintf(stderr,
"Usage: %s [BATTERYDEVICE]\n"
" BATTERYDEVICE UPower battery device path, e.g.\n"
" '%s'\n",
progname, POTATO_DEFAULT_BATTERY_DEVICE);
return 1;
}
// initialize error
dbus_error_init(&err);
// validate the path
if (!dbus_validate_path(batDev, &err)) {
fprintf(stderr, "%s: %s\n", err.name, err.message);
return 3;
}
// connect to system bus
conn = dbus_bus_get(DBUS_BUS_SYSTEM, &err);
if (conn == NULL) {
fprintf(stderr, "%s: %s\n", err.name, err.message);
return 1;
}
// create a new method call
toSend =
dbus_message_new_method_call(POTATO_DESTINATION, batDev,
POTATO_CALL_INTERFACE,
POTATO_CALL_METHOD);
// append the arguments
dbus_message_append_args(toSend,
DBUS_TYPE_STRING, &POTATO_TARGET_TYPE,
DBUS_TYPE_INVALID);
// send the message
reply =
dbus_connection_send_with_reply_and_block(conn, toSend,
POTATO_TIMEOUT, &err);
if (reply == NULL) {
fprintf(stderr, "%s: %s\n", err.name, err.message);
dbus_message_unref(toSend);
dbus_connection_unref(conn);
return 2;
}
// destroy the sent message
dbus_message_unref(toSend);
// pick out the array
dbus_message_iter_init(reply, &itMsg);
dbus_message_iter_recurse(&itMsg, &itArr);
while (dbus_message_iter_has_next(&itArr)) {
const char *key;
dbus_message_iter_recurse(&itArr, &itDict);
dbus_message_iter_get_basic(&itDict, &key);
dbus_message_iter_next(&itDict);
dbus_message_iter_recurse(&itDict, &itVar);
if (strcmp(key, POTATO_PROPERTY_STATE) == 0) {
dbus_message_iter_get_basic(&itVar, &state);
} else if (strcmp(key, POTATO_PROPERTY_PERCENTAGE) == 0) {
dbus_message_iter_get_basic(&itVar, &percentage);
}
dbus_message_iter_next(&itArr);
}
// destroy the reply
dbus_message_unref(reply);
// disconnect
dbus_connection_unref(conn);
if (state == -1 || percentage == -1.0) {
fprintf(stderr, "warning: some properties not set correctly\n");
}
if (state == 1) {
// charging
state_string = POTATO_STATE_CHARGING;
} else if (percentage < 10.0) {
state_string = POTATO_STATE_CRITICAL;
} else if (percentage < 20.0) {
state_string = POTATO_STATE_LOW;
}
// output the percentage and the state string
printf("%.0f%%%s\n", floorto(percentage, 0), state_string);
return 0;
}
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