dockapps/wmbattery/upower.c

/* Not particularly good interface to hal, for programs that used to use
 * apm.
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/wait.h>
#include <upower.h>
#include "apm.h"

#define MAX_RETRIES 3

struct context {
	int current;
	int needed;
	guint state;
	int percentage;
	gboolean ac;
	int time;
};

static void get_devinfo(gpointer device, gpointer result)
{
	gboolean online;
	gdouble percentage;
	guint state;
	guint kind;
	gint64 time_to_empty;
	gint64 time_to_full;
	struct context *ctx = result;

	g_object_get(G_OBJECT(device), "percentage", &percentage,
		"online", &online,
		"state", &state,
		"kind", &kind,
		"time-to-empty", &time_to_empty,
		"time-to-full", &time_to_full,
		NULL);
	if (kind == UP_DEVICE_KIND_BATTERY) {
		if (ctx->current == ctx->needed) {
			ctx->percentage = (int)percentage;
			ctx->state = state;
			if (time_to_empty)
				ctx->time = time_to_empty;
			else
				ctx->time = time_to_full;
		}
		ctx->current++;
	} else if (kind == UP_DEVICE_KIND_LINE_POWER) {
		ctx->ac |= online;
	}
}

/* Fill the passed apm_info struct. */
static int upower_read_child(int battery, apm_info *info)
{
	UpClient * up;
	GPtrArray *devices = NULL;

	up = up_client_new();

	if (!up)
		return -1;

	#if !UP_CHECK_VERSION(0, 9, 99)
	/* Allow a battery that was not present before to appear. */
	up_client_enumerate_devices_sync(up, NULL, NULL);
	#endif

	devices = up_client_get_devices(up);

	if (!devices)
		return -1;

	info->battery_flags = 0;
	info->using_minutes = 0;

	struct context ctx = {
		.current = 0,
		.needed = battery - 1,
		.state = UP_DEVICE_STATE_UNKNOWN,
		.percentage = -1,
		.ac = FALSE,
		.time = -1
	};

	g_ptr_array_foreach(devices, &get_devinfo, &ctx);

	info->ac_line_status = ctx.ac;

	/* remaining_time and charge_level.percentage are not a mandatory
	 * keys, so if not present, -1 will be returned */
	info->battery_time = ctx.time;
	info->battery_percentage = ctx.percentage;
	if (ctx.state == UP_DEVICE_STATE_DISCHARGING) {
		info->battery_status = BATTERY_STATUS_CHARGING;
		/* charge_level.warning and charge_level.low are not
		 * required to be available; this is good enough */
		if (info->battery_percentage < 1)
			info->battery_status = BATTERY_STATUS_CRITICAL;
		else if (info->battery_percentage < 10)
			info->battery_status = BATTERY_STATUS_LOW;
	} else if (info->ac_line_status && ctx.state == UP_DEVICE_STATE_CHARGING) {
		info->battery_status = BATTERY_STATUS_CHARGING;
		info->battery_flags = info->battery_flags | BATTERY_FLAGS_CHARGING;
	} else if (info->ac_line_status) {
		/* Must be fully charged. */
		info->battery_status = BATTERY_STATUS_HIGH;
	} else {
		fprintf(stderr, "unknown battery state\n");
	}

	if (ctx.percentage < 0) {
		info->battery_percentage = 0;
		info->battery_time = 0;
		info->battery_status = BATTERY_STATUS_ABSENT;
	}

	g_ptr_array_unref(devices);
	return 0;
}

static int upower_read_work(int battery, apm_info *info)
{
	int sp[2];
	int child;
	int status;
	ssize_t cv;

	if (socketpair(AF_UNIX, SOCK_DGRAM, 0, sp) < 0) {
		fprintf(stderr, "socketpair: %s", strerror(errno));
		goto fail;
	}

	child = fork();
	if (child < 0) {
		fprintf(stderr, "fork: %s", strerror(errno));
		goto fail_close;
	}

	if (child == 0) {
		/* child process does work, writes failure or result back to parent */
		close(sp[0]);
		status = upower_read_child(battery, info);
		if (status < 0) {
			cv = send(sp[1], &status, sizeof(status), 0);
		}
		else {
			cv = send(sp[1], info, sizeof(*info), 0);
		}
		exit(cv < 0);
	}
	close(sp[1]);

	child = waitpid(child, &status, 0);
	if (child < 0) {
		fprintf(stderr, "waitpid: %s status=%d", strerror(errno), status);
		goto fail_close0;
	}

	cv = recv(sp[0], info, sizeof(*info), 0);
	if (cv < 0) {
		fprintf(stderr, "recv: %s", strerror(errno));
		goto fail_close0;
	}
	else if (cv == sizeof(status)) {
		memcpy(&status, info, sizeof(status));
		goto fail_close0;
	}
	else if (cv != sizeof(*info)) {
		fprintf(stderr, "recv: unexpected size %zd", cv);
		goto fail_close0;
	}

	close(sp[0]);
	return 0;

	fail_close:
	close(sp[1]);
	fail_close0:
	close(sp[0]);
	fail:
	return -1;
}

int upower_supported(void)
{
	apm_info info;
	return !(upower_read_work(1, &info) < 0);
}


int upower_read(int battery, apm_info *info)
{
	static int retries = 0;

	if (upower_read_work(battery, info) < 0) {
		retries++;
		if (retries < MAX_RETRIES)
			return 0; /* fine immediately after hibernation */
		else
			return -1;
	}

	retries = 0;
	return 0;
}