charger/charger.c - AOSPA/android_system_core - Gitiles

 /*
  * Copyright (C) 2011 The Android Open Source Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *      http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */

 //#define DEBUG_UEVENTS
 #define CHARGER_KLOG_LEVEL 6

 #include <dirent.h>
 #include <errno.h>
 #include <fcntl.h>
 #include <linux/input.h>
 #include <linux/netlink.h>
 #include <stdbool.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <sys/poll.h>
 #include <sys/socket.h>
 #include <sys/stat.h>
 #include <sys/types.h>
 #include <sys/un.h>
 #include <time.h>
 #include <unistd.h>

 #include <cutils/android_reboot.h>
 #include <cutils/klog.h>
 #include <cutils/list.h>
 #include <cutils/uevent.h>

 #include "minui/minui.h"

 #ifndef max
 #define max(a,b) ((a) > (b) ? (a) : (b))
 #endif

 #ifndef min
 #define min(a,b) ((a) < (b) ? (a) : (b))
 #endif

 #define MSEC_PER_SEC            (1000LL)
 #define NSEC_PER_MSEC           (1000000LL)

 #define SCREEN_ON_TIME          (5 * MSEC_PER_SEC)
 #define POWER_ON_KEY_TIME       (5 * MSEC_PER_SEC)
 #define UNPLUGGED_SHUTDOWN_TIME (10 * MSEC_PER_SEC)

 #define LOGE(x...) do { KLOG_ERROR("charger", x); } while (0)
 #define LOGI(x...) do { KLOG_INFO("charger", x); } while (0)
 #define LOGV(x...) do { KLOG_DEBUG("charger", x); } while (0)

 struct key_state {
     bool pending;
     bool down;
     int64_t timestamp;
 };

 struct power_supply {
     struct listnode list;
     char name[256];
     char type[32];
     bool online;
     bool valid;
 };

 struct charger {
     int64_t next_screen_transition;
     int64_t next_key_check;
     int64_t next_pwr_check;
     bool screen_on;

     struct key_state keys[KEY_MAX + 1];
     gr_surface surf_charging;
     int uevent_fd;

     struct listnode supplies;
     int num_supplies;
     int num_supplies_online;

     struct power_supply *battery;
 };

 struct uevent {
     const char *action;
     const char *path;
     const char *subsystem;
     const char *ps_name;
     const char *ps_type;
     const char *ps_online;
 };

 static int char_width;
 static int char_height;

 struct charger charger_state;

 /* current time in milliseconds */
 static int64_t curr_time_ms(void)
 {
     struct timespec tm;
     clock_gettime(CLOCK_MONOTONIC, &tm);
     return tm.tv_sec * MSEC_PER_SEC + (tm.tv_nsec / NSEC_PER_MSEC);
 }

 static void clear_screen(void)
 {
     gr_color(0, 0, 0, 255);
     gr_fill(0, 0, gr_fb_width(), gr_fb_height());
 };

 static int read_file(const char *path, char *buf, size_t sz)
 {
     int fd;
     size_t cnt;

     fd = open(path, O_RDONLY, 0);
     if (fd < 0)
         goto err;

     cnt = read(fd, buf, sz - 1);
     if (cnt <= 0)
         goto err;
     buf[cnt] = '\0';
     if (buf[cnt - 1] == '\n') {
         cnt--;
         buf[cnt] = '\0';
     }

     close(fd);
     return cnt;

 err:
     if (fd >= 0)
         close(fd);
     return -1;
 }

 static int read_file_int(const char *path, int *val)
 {
     char buf[32];
     int ret;
     int tmp;
     char *end;

     ret = read_file(path, buf, sizeof(buf));
     if (ret < 0)
         return -1;

     tmp = strtol(buf, &end, 0);
     if (end == buf ||
         ((end < buf+sizeof(buf)) && (*end != '\n' && *end != '\0')))
         goto err;

     *val = tmp;
     return 0;

 err:
     return -1;
 }

 static struct power_supply *find_supply(struct charger *charger,
                                         const char *name)
 {
     struct listnode *node;
     struct power_supply *supply;

     list_for_each(node, &charger->supplies) {
         supply = node_to_item(node, struct power_supply, list);
         if (!strncmp(name, supply->name, sizeof(supply->name)))
             return supply;
     }
     return NULL;
 }

 static struct power_supply *add_supply(struct charger *charger,
                                        const char *name, const char *type,
                                        bool online)
 {
     struct power_supply *supply;

     supply = calloc(1, sizeof(struct power_supply));
     if (!supply)
         return NULL;

     strlcpy(supply->name, name, sizeof(supply->name));
     strlcpy(supply->type, type, sizeof(supply->type));
     supply->online = online;
     list_add_tail(&charger->supplies, &supply->list);
     charger->num_supplies++;
     LOGV("... added %s %s %d\n", supply->name, supply->type, online);
     return supply;
 }

 static void remove_supply(struct charger *charger, struct power_supply *supply)
 {
     if (!supply)
         return;
     list_remove(&supply->list);
     charger->num_supplies--;
     free(supply);
 }

 static void parse_uevent(const char *msg, struct uevent *uevent)
 {
     uevent->action = "";
     uevent->path = "";
     uevent->subsystem = "";
     uevent->ps_name = "";
     uevent->ps_online = "";
     uevent->ps_type = "";

     /* currently ignoring SEQNUM */
     while (*msg) {
 #ifdef DEBUG_UEVENTS
         LOGV("uevent str: %s\n", msg);
 #endif
         if (!strncmp(msg, "ACTION=", 7)) {
             msg += 7;
             uevent->action = msg;
         } else if (!strncmp(msg, "DEVPATH=", 8)) {
             msg += 8;
             uevent->path = msg;
         } else if (!strncmp(msg, "SUBSYSTEM=", 10)) {
             msg += 10;
             uevent->subsystem = msg;
         } else if (!strncmp(msg, "POWER_SUPPLY_NAME=", 18)) {
             msg += 18;
             uevent->ps_name = msg;
         } else if (!strncmp(msg, "POWER_SUPPLY_ONLINE=", 20)) {
             msg += 20;
             uevent->ps_online = msg;
         } else if (!strncmp(msg, "POWER_SUPPLY_TYPE=", 18)) {
             msg += 18;
             uevent->ps_type = msg;
         }

         /* advance to after the next \0 */
         while (*msg++)
             ;
     }

     LOGV("event { '%s', '%s', '%s', '%s', '%s', '%s' }\n",
          uevent->action, uevent->path, uevent->subsystem,
          uevent->ps_name, uevent->ps_type, uevent->ps_online);
 }

 static void process_ps_uevent(struct charger *charger, struct uevent *uevent)
 {
     int online;
     char ps_type[32];
     struct power_supply *supply = NULL;
     int i;
     bool was_online = false;
     bool battery = false;

     if (uevent->ps_type[0] == '\0') {
         char *path;
         int ret;

         if (uevent->path[0] == '\0')
             return;
         ret = asprintf(&path, "/sys/%s/type", uevent->path);
         if (ret <= 0)
             return;
         ret = read_file(path, ps_type, sizeof(ps_type));
         free(path);
         if (ret < 0)
             return;
     } else {
         strlcpy(ps_type, uevent->ps_type, sizeof(ps_type));
     }

     if (!strncmp(ps_type, "Battery", 7))
         battery = true;

     online = atoi(uevent->ps_online);
     supply = find_supply(charger, uevent->ps_name);
     if (supply) {
         was_online = supply->online;
         supply->online = online;
     }

     if (!strcmp(uevent->action, "add")) {
         if (!supply) {
             supply = add_supply(charger, uevent->ps_name, ps_type, online);
             if (!supply) {
                 LOGE("cannot add supply '%s' (%s %d)\n", uevent->ps_name,
                      uevent->ps_type, online);
                 return;
             }
             /* only pick up the first battery for now */
             if (battery && !charger->battery)
                 charger->battery = supply;
         } else {
             LOGE("supply '%s' already exists..\n", uevent->ps_name);
         }
     } else if (!strcmp(uevent->action, "remove")) {
         if (supply) {
             if (charger->battery == supply)
                 charger->battery = NULL;
             remove_supply(charger, supply);
             supply = NULL;
         }
     } else if (!strcmp(uevent->action, "change")) {
         if (!supply) {
             LOGE("power supply '%s' not found ('%s' %d)\n",
                  uevent->ps_name, ps_type, online);
             return;
         }
     } else {
         return;
     }

     /* allow battery to be managed in the supply list but make it not
      * contribute to online power supplies. */
     if (!battery) {
         if (was_online && !online)
             charger->num_supplies_online--;
         else if (supply && !was_online && online)
             charger->num_supplies_online++;
     }

     LOGI("power supply %s (%s) %s (action=%s num_online=%d num_supplies=%d)\n",
          uevent->ps_name, ps_type, battery ? "" : online ? "online" : "offline",
          uevent->action, charger->num_supplies_online, charger->num_supplies);
 }

 static void process_uevent(struct charger *charger, struct uevent *uevent)
 {
     if (!strcmp(uevent->subsystem, "power_supply"))
         process_ps_uevent(charger, uevent);
 }

 #define UEVENT_MSG_LEN  1024
 static int handle_uevent_fd(struct charger *charger, int fd)
 {
     char msg[UEVENT_MSG_LEN+2];
     int n;

     if (fd < 0)
         return -1;

     while (true) {
         struct uevent uevent;

         n = uevent_kernel_multicast_recv(fd, msg, UEVENT_MSG_LEN);
         if (n <= 0)
             break;
         if (n >= UEVENT_MSG_LEN)   /* overflow -- discard */
             continue;

         msg[n] = '\0';
         msg[n+1] = '\0';

         parse_uevent(msg, &uevent);
         process_uevent(charger, &uevent);
     }

     return 0;
 }

 static int uevent_callback(int fd, short revents, void *data)
 {
     struct charger *charger = data;

     if (!(revents & POLLIN))
         return -1;
     return handle_uevent_fd(charger, fd);
 }

 /* force the kernel to regenerate the change events for the existing
  * devices, if valid */
 static void do_coldboot(struct charger *charger, DIR *d, const char *event,
                         bool follow_links, int max_depth)
 {
     struct dirent *de;
     int dfd, fd;

     dfd = dirfd(d);

     fd = openat(dfd, "uevent", O_WRONLY);
     if (fd >= 0) {
         write(fd, event, strlen(event));
         close(fd);
         handle_uevent_fd(charger, charger->uevent_fd);
     }

     while ((de = readdir(d)) && max_depth > 0) {
         DIR *d2;

         LOGV("looking at '%s'\n", de->d_name);

         if ((de->d_type != DT_DIR && !(de->d_type == DT_LNK && follow_links)) ||
            de->d_name[0] == '.') {
             LOGV("skipping '%s' type %d (depth=%d follow=%d)\n",
                  de->d_name, de->d_type, max_depth, follow_links);
             continue;
         }
         LOGV("can descend into '%s'\n", de->d_name);

         fd = openat(dfd, de->d_name, O_RDONLY | O_DIRECTORY);
         if (fd < 0) {
             LOGE("cannot openat %d '%s' (%d: %s)\n", dfd, de->d_name,
                  errno, strerror(errno));
             continue;
         }

         d2 = fdopendir(fd);
         if (d2 == 0)
             close(fd);
         else {
             LOGV("opened '%s'\n", de->d_name);
             do_coldboot(charger, d2, event, follow_links, max_depth - 1);
             closedir(d2);
         }
     }
 }

 static void coldboot(struct charger *charger, const char *path,
                      const char *event)
 {
     char str[256];

     LOGV("doing coldboot '%s' in '%s'\n", event, path);
     DIR *d = opendir(path);
     if (d) {
         snprintf(str, sizeof(str), "%s\n", event);
         do_coldboot(charger, d, str, true, 1);
         closedir(d);
     }
 }

 static int draw_text(const char *str, int x, int y)
 {
     int str_len_px = gr_measure(str);

     if (x < 0)
         x = (gr_fb_width() - str_len_px) / 2;
     if (y < 0)
         y = (gr_fb_height() - char_height) / 2;
     gr_text(x, y, str);

     return y + char_height;
 }

 static void android_green(void)
 {
     gr_color(0xa4, 0xc6, 0x39, 255);
 }

 static void redraw_screen(struct charger *charger)
 {
     int surf_height;
     int surf_width;
     int x;
     int y = 0;
     int batt_cap;
     int ret;
     char cap_string[128];
     char cap_path[256];

     clear_screen();

     if (charger->surf_charging) {
         surf_width = gr_get_width(charger->surf_charging);
         surf_height = gr_get_height(charger->surf_charging);
         x = (gr_fb_width() - surf_width) / 2 ;
         y = (gr_fb_height() - surf_height) / 2 ;

         gr_blit(charger->surf_charging, 0, 0,
                 surf_width, surf_height,
                 x, y);
         y += surf_height;
     } else {
         android_green();
         y = draw_text("Charging!", -1, -1);
     }

     cap_string[0] = '\0';
     if (charger->battery) {
         ret = snprintf(cap_path, sizeof(cap_path),
                        "/sys/class/power_supply/%s/capacity",
                        charger->battery->name);
         if (ret <= 0)
             goto done;
         ret = read_file_int(cap_path, &batt_cap);
         if (ret >= 0)
             snprintf(cap_string, sizeof(cap_string), "%d/100", batt_cap);
     }

     if (cap_string[0] == '\0')
         snprintf(cap_string, sizeof(cap_string), "?\?/100");

     y += 25;
     android_green();
     draw_text(cap_string, -1, y);

 done:
     gr_flip();
 }

 static void update_screen_state(struct charger *charger, int64_t now,
                                 bool force)
 {
     if (!force && ((now < charger->next_screen_transition) ||
                    (charger->next_screen_transition == -1)))
         return;

     if (!charger->screen_on)
         charger->next_screen_transition = now + SCREEN_ON_TIME;
     else
         charger->next_screen_transition = -1;
     charger->screen_on = !charger->screen_on;

     gr_fb_blank(!charger->screen_on);
     if (charger->screen_on)
         redraw_screen(charger);
     LOGV("[%lld] screen %s\n", now, charger->screen_on ? "on" : "off");
 }

 static void update_input_state(struct charger *charger,
                                struct input_event *ev,
                                int64_t now)
 {
     int down = !!ev->value;

     if (ev->type != EV_KEY || ev->code > KEY_MAX)
         return;

     /* only record the down even timestamp, as the amount
      * of time the key spent not being pressed is not useful */
     if (down)
         charger->keys[ev->code].timestamp = now;
     charger->keys[ev->code].down = down;
     charger->keys[ev->code].pending = true;
     if (down) {
         LOGV("[%lld] key[%d] down\n", now, ev->code);
     } else {
         int64_t duration = now - charger->keys[ev->code].timestamp;
         int64_t secs = duration / 1000;
         int64_t msecs = duration - secs * 1000;
         LOGV("[%lld] key[%d] up (was down for %lld.%lldsec)\n", now,
             ev->code, secs, msecs);
     }
 }

 static void set_next_key_check(struct charger *charger,
                                struct key_state *key,
                                int64_t timeout)
 {
     int64_t then = key->timestamp + timeout;

     if (charger->next_key_check == -1 || then < charger->next_key_check)
         charger->next_key_check = then;
 }

 static void process_key(struct charger *charger, int code, int64_t now)
 {
     struct key_state *key = &charger->keys[code];
     int64_t next_key_check;

     if (code == KEY_POWER) {
         if (key->down) {
             int64_t reboot_timeout = key->timestamp + POWER_ON_KEY_TIME;
             if (now >= reboot_timeout) {
                 LOGI("[%lld] rebooting\n", now);
                 android_reboot(ANDROID_RB_RESTART, 0, 0);
             } else {
                 /* if the key is pressed but timeout hasn't expired,
                  * make sure we wake up at the right-ish time to check
                  */
                 set_next_key_check(charger, key, POWER_ON_KEY_TIME);
             }
         } else {
             /* if the power key got released, force screen state cycle */
             if (key->pending)
                 update_screen_state(charger, now, true);
         }
     }

     key->pending = false;
 }

 static void handle_input_state(struct charger *charger, int64_t now)
 {
     process_key(charger, KEY_POWER, now);

     if (charger->next_key_check != -1 && now > charger->next_key_check)
         charger->next_key_check = -1;
 }

 static void handle_power_supply_state(struct charger *charger, int64_t now)
 {
     if (charger->num_supplies_online == 0) {
         if (charger->next_pwr_check == -1) {
             charger->next_pwr_check = now + UNPLUGGED_SHUTDOWN_TIME;
             LOGI("[%lld] device unplugged: shutting down in %lld (@ %lld)\n",
                  now, UNPLUGGED_SHUTDOWN_TIME, charger->next_pwr_check);
         } else if (now >= charger->next_pwr_check) {
             LOGI("[%lld] shutting down\n", now);
             android_reboot(ANDROID_RB_POWEROFF, 0, 0);
         } else {
             /* otherwise we already have a shutdown timer scheduled */
         }
     } else {
         /* online supply present, reset shutdown timer if set */
         if (charger->next_pwr_check != -1) {
             LOGI("[%lld] device plugged in: shutdown cancelled\n", now);
             update_screen_state(charger, now, true);
         }
         charger->next_pwr_check = -1;
     }
 }

 static void wait_next_event(struct charger *charger, int64_t now)
 {
     int64_t next_event = INT64_MAX;
     int64_t timeout;
     struct input_event ev;
     int ret;

     LOGV("[%lld] next screen: %lld next key: %lld next pwr: %lld\n", now,
          charger->next_screen_transition, charger->next_key_check,
          charger->next_pwr_check);

     /* TODO: right now it's just screen on/off and keys, but later I'm sure
      *       there will be animations */
     if (charger->next_screen_transition != -1)
         next_event = charger->next_screen_transition;
     if (charger->next_key_check != -1 && charger->next_key_check < next_event)
         next_event = charger->next_key_check;
     if (charger->next_pwr_check != -1 && charger->next_pwr_check < next_event)
         next_event = charger->next_pwr_check;

     if (next_event != -1 && next_event != INT64_MAX)
         timeout = max(0, next_event - now);
     else
         timeout = -1;
     LOGV("[%lld] blocking (%lld)\n", now, timeout);
     ret = ev_wait((int)timeout);
     if (!ret)
         ev_dispatch();
 }

 static int input_callback(int fd, short revents, void *data)
 {
     struct charger *charger = data;
     struct input_event ev;
     int ret;

     ret = ev_get_input(fd, revents, &ev);
     if (ret)
         return -1;
     update_input_state(charger, &ev, curr_time_ms());
     return 0;
 }

 static void event_loop(struct charger *charger)
 {
     int ret;

     while (true) {
         int64_t now = curr_time_ms();

         LOGV("[%lld] event_loop()\n", now);
         handle_input_state(charger, now);
         update_screen_state(charger, now, false);
         handle_power_supply_state(charger, now);

         wait_next_event(charger, now);
     }
 }

 int main(int argc, char **argv)
 {
     int ret;
     struct charger *charger = &charger_state;
     int64_t now = curr_time_ms() - 1;
     int fd;

     list_init(&charger->supplies);

     klog_init();
     klog_set_level(CHARGER_KLOG_LEVEL);

     gr_init();
     gr_font_size(&char_width, &char_height);

     ev_init(input_callback, charger);

     fd = uevent_open_socket(64*1024, true);
     if (fd >= 0) {
         fcntl(fd, F_SETFL, O_NONBLOCK);
         ev_add_fd(fd, uevent_callback, charger);
     }
     charger->uevent_fd = fd;
     coldboot(charger, "/sys/class/power_supply", "add");

     ret = res_create_surface("charging", &charger->surf_charging);
     if (ret < 0) {
         LOGE("Cannot load image\n");
         charger->surf_charging = NULL;
     }

     gr_fb_blank(true);

     charger->next_screen_transition = now - 1;
     charger->next_key_check = -1;
     charger->next_pwr_check = -1;
     charger->screen_on = false;

     event_loop(charger);

     return 0;
 }
	/*
	* Copyright (C) 2011 The Android Open Source Project
	*
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/

	//#define DEBUG_UEVENTS
	#define CHARGER_KLOG_LEVEL 6

	#include <dirent.h>
	#include <errno.h>
	#include <fcntl.h>
	#include <linux/input.h>
	#include <linux/netlink.h>
	#include <stdbool.h>
	#include <stdio.h>
	#include <stdlib.h>
	#include <string.h>
	#include <sys/poll.h>
	#include <sys/socket.h>
	#include <sys/stat.h>
	#include <sys/types.h>
	#include <sys/un.h>
	#include <time.h>
	#include <unistd.h>

	#include <cutils/android_reboot.h>
	#include <cutils/klog.h>
	#include <cutils/list.h>
	#include <cutils/uevent.h>

	#include "minui/minui.h"

	#ifndef max
	#define max(a,b) ((a) > (b) ? (a) : (b))
	#endif

	#ifndef min
	#define min(a,b) ((a) < (b) ? (a) : (b))
	#endif

	#define MSEC_PER_SEC (1000LL)
	#define NSEC_PER_MSEC (1000000LL)

	#define SCREEN_ON_TIME (5 * MSEC_PER_SEC)
	#define POWER_ON_KEY_TIME (5 * MSEC_PER_SEC)
	#define UNPLUGGED_SHUTDOWN_TIME (10 * MSEC_PER_SEC)

	#define LOGE(x...) do { KLOG_ERROR("charger", x); } while (0)
	#define LOGI(x...) do { KLOG_INFO("charger", x); } while (0)
	#define LOGV(x...) do { KLOG_DEBUG("charger", x); } while (0)

	struct key_state {
	bool pending;
	bool down;
	int64_t timestamp;
	};

	struct power_supply {
	struct listnode list;
	char name[256];
	char type[32];
	bool online;
	bool valid;
	};

	struct charger {
	int64_t next_screen_transition;
	int64_t next_key_check;
	int64_t next_pwr_check;
	bool screen_on;

	struct key_state keys[KEY_MAX + 1];
	gr_surface surf_charging;
	int uevent_fd;

	struct listnode supplies;
	int num_supplies;
	int num_supplies_online;

	struct power_supply *battery;
	};

	struct uevent {
	const char *action;
	const char *path;
	const char *subsystem;
	const char *ps_name;
	const char *ps_type;
	const char *ps_online;
	};

	static int char_width;
	static int char_height;

	struct charger charger_state;

	/* current time in milliseconds */
	static int64_t curr_time_ms(void)
	{
	struct timespec tm;
	clock_gettime(CLOCK_MONOTONIC, &tm);
	return tm.tv_sec * MSEC_PER_SEC + (tm.tv_nsec / NSEC_PER_MSEC);
	}

	static void clear_screen(void)
	{
	gr_color(0, 0, 0, 255);
	gr_fill(0, 0, gr_fb_width(), gr_fb_height());
	};

	static int read_file(const char path, char buf, size_t sz)
	{
	int fd;
	size_t cnt;

	fd = open(path, O_RDONLY, 0);
	if (fd < 0)
	goto err;

	cnt = read(fd, buf, sz - 1);
	if (cnt <= 0)
	goto err;
	buf[cnt] = '\0';
	if (buf[cnt - 1] == '\n') {
	cnt--;
	buf[cnt] = '\0';
	}

	close(fd);
	return cnt;

	err:
	if (fd >= 0)
	close(fd);
	return -1;
	}

	static int read_file_int(const char path, int val)
	{
	char buf[32];
	int ret;
	int tmp;
	char *end;

	ret = read_file(path, buf, sizeof(buf));
	if (ret < 0)
	return -1;

	tmp = strtol(buf, &end, 0);
	if (end == buf \|\|
	((end < buf+sizeof(buf)) && (end != '\n' && end != '\0')))
	goto err;

	*val = tmp;
	return 0;

	err:
	return -1;
	}

	static struct power_supply find_supply(struct charger charger,
	const char *name)
	{
	struct listnode *node;
	struct power_supply *supply;

	list_for_each(node, &charger->supplies) {
	supply = node_to_item(node, struct power_supply, list);
	if (!strncmp(name, supply->name, sizeof(supply->name)))
	return supply;
	}
	return NULL;
	}

	static struct power_supply add_supply(struct charger charger,
	const char name, const char type,
	bool online)
	{
	struct power_supply *supply;

	supply = calloc(1, sizeof(struct power_supply));
	if (!supply)
	return NULL;

	strlcpy(supply->name, name, sizeof(supply->name));
	strlcpy(supply->type, type, sizeof(supply->type));
	supply->online = online;
	list_add_tail(&charger->supplies, &supply->list);
	charger->num_supplies++;
	LOGV("... added %s %s %d\n", supply->name, supply->type, online);
	return supply;
	}

	static void remove_supply(struct charger charger, struct power_supply supply)
	{
	if (!supply)
	return;
	list_remove(&supply->list);
	charger->num_supplies--;
	free(supply);
	}

	static void parse_uevent(const char msg, struct uevent uevent)
	{
	uevent->action = "";
	uevent->path = "";
	uevent->subsystem = "";
	uevent->ps_name = "";
	uevent->ps_online = "";
	uevent->ps_type = "";

	/* currently ignoring SEQNUM */
	while (*msg) {
	#ifdef DEBUG_UEVENTS
	LOGV("uevent str: %s\n", msg);
	#endif
	if (!strncmp(msg, "ACTION=", 7)) {
	msg += 7;
	uevent->action = msg;
	} else if (!strncmp(msg, "DEVPATH=", 8)) {
	msg += 8;
	uevent->path = msg;
	} else if (!strncmp(msg, "SUBSYSTEM=", 10)) {
	msg += 10;
	uevent->subsystem = msg;
	} else if (!strncmp(msg, "POWER_SUPPLY_NAME=", 18)) {
	msg += 18;
	uevent->ps_name = msg;
	} else if (!strncmp(msg, "POWER_SUPPLY_ONLINE=", 20)) {
	msg += 20;
	uevent->ps_online = msg;
	} else if (!strncmp(msg, "POWER_SUPPLY_TYPE=", 18)) {
	msg += 18;
	uevent->ps_type = msg;
	}

	/* advance to after the next \0 */
	while (*msg++)
	;
	}

	LOGV("event { '%s', '%s', '%s', '%s', '%s', '%s' }\n",
	uevent->action, uevent->path, uevent->subsystem,
	uevent->ps_name, uevent->ps_type, uevent->ps_online);
	}

	static void process_ps_uevent(struct charger charger, struct uevent uevent)
	{
	int online;
	char ps_type[32];
	struct power_supply *supply = NULL;
	int i;
	bool was_online = false;
	bool battery = false;

	if (uevent->ps_type[0] == '\0') {
	char *path;
	int ret;

	if (uevent->path[0] == '\0')
	return;
	ret = asprintf(&path, "/sys/%s/type", uevent->path);
	if (ret <= 0)
	return;
	ret = read_file(path, ps_type, sizeof(ps_type));
	free(path);
	if (ret < 0)
	return;
	} else {
	strlcpy(ps_type, uevent->ps_type, sizeof(ps_type));
	}

	if (!strncmp(ps_type, "Battery", 7))
	battery = true;

	online = atoi(uevent->ps_online);
	supply = find_supply(charger, uevent->ps_name);
	if (supply) {
	was_online = supply->online;
	supply->online = online;
	}

	if (!strcmp(uevent->action, "add")) {
	if (!supply) {
	supply = add_supply(charger, uevent->ps_name, ps_type, online);
	if (!supply) {
	LOGE("cannot add supply '%s' (%s %d)\n", uevent->ps_name,
	uevent->ps_type, online);
	return;
	}
	/* only pick up the first battery for now */
	if (battery && !charger->battery)
	charger->battery = supply;
	} else {
	LOGE("supply '%s' already exists..\n", uevent->ps_name);
	}
	} else if (!strcmp(uevent->action, "remove")) {
	if (supply) {
	if (charger->battery == supply)
	charger->battery = NULL;
	remove_supply(charger, supply);
	supply = NULL;
	}
	} else if (!strcmp(uevent->action, "change")) {
	if (!supply) {
	LOGE("power supply '%s' not found ('%s' %d)\n",
	uevent->ps_name, ps_type, online);
	return;
	}
	} else {
	return;
	}

	/* allow battery to be managed in the supply list but make it not
	* contribute to online power supplies. */
	if (!battery) {
	if (was_online && !online)
	charger->num_supplies_online--;
	else if (supply && !was_online && online)
	charger->num_supplies_online++;
	}

	LOGI("power supply %s (%s) %s (action=%s num_online=%d num_supplies=%d)\n",
	uevent->ps_name, ps_type, battery ? "" : online ? "online" : "offline",
	uevent->action, charger->num_supplies_online, charger->num_supplies);
	}

	static void process_uevent(struct charger charger, struct uevent uevent)
	{
	if (!strcmp(uevent->subsystem, "power_supply"))
	process_ps_uevent(charger, uevent);
	}

	#define UEVENT_MSG_LEN 1024
	static int handle_uevent_fd(struct charger *charger, int fd)
	{
	char msg[UEVENT_MSG_LEN+2];
	int n;

	if (fd < 0)
	return -1;

	while (true) {
	struct uevent uevent;

	n = uevent_kernel_multicast_recv(fd, msg, UEVENT_MSG_LEN);
	if (n <= 0)
	break;
	if (n >= UEVENT_MSG_LEN) /* overflow -- discard */
	continue;

	msg[n] = '\0';
	msg[n+1] = '\0';

	parse_uevent(msg, &uevent);
	process_uevent(charger, &uevent);
	}

	return 0;
	}

	static int uevent_callback(int fd, short revents, void *data)
	{
	struct charger *charger = data;

	if (!(revents & POLLIN))
	return -1;
	return handle_uevent_fd(charger, fd);
	}

	/* force the kernel to regenerate the change events for the existing
	* devices, if valid */
	static void do_coldboot(struct charger charger, DIR d, const char *event,
	bool follow_links, int max_depth)
	{
	struct dirent *de;
	int dfd, fd;

	dfd = dirfd(d);

	fd = openat(dfd, "uevent", O_WRONLY);
	if (fd >= 0) {
	write(fd, event, strlen(event));
	close(fd);
	handle_uevent_fd(charger, charger->uevent_fd);
	}

	while ((de = readdir(d)) && max_depth > 0) {
	DIR *d2;

	LOGV("looking at '%s'\n", de->d_name);

	if ((de->d_type != DT_DIR && !(de->d_type == DT_LNK && follow_links)) \|\|
	de->d_name[0] == '.') {
	LOGV("skipping '%s' type %d (depth=%d follow=%d)\n",
	de->d_name, de->d_type, max_depth, follow_links);
	continue;
	}
	LOGV("can descend into '%s'\n", de->d_name);

	fd = openat(dfd, de->d_name, O_RDONLY \| O_DIRECTORY);
	if (fd < 0) {
	LOGE("cannot openat %d '%s' (%d: %s)\n", dfd, de->d_name,
	errno, strerror(errno));
	continue;
	}

	d2 = fdopendir(fd);
	if (d2 == 0)
	close(fd);
	else {
	LOGV("opened '%s'\n", de->d_name);
	do_coldboot(charger, d2, event, follow_links, max_depth - 1);
	closedir(d2);
	}
	}
	}

	static void coldboot(struct charger charger, const char path,
	const char *event)
	{
	char str[256];

	LOGV("doing coldboot '%s' in '%s'\n", event, path);
	DIR *d = opendir(path);
	if (d) {
	snprintf(str, sizeof(str), "%s\n", event);
	do_coldboot(charger, d, str, true, 1);
	closedir(d);
	}
	}

	static int draw_text(const char *str, int x, int y)
	{
	int str_len_px = gr_measure(str);

	if (x < 0)
	x = (gr_fb_width() - str_len_px) / 2;
	if (y < 0)
	y = (gr_fb_height() - char_height) / 2;
	gr_text(x, y, str);

	return y + char_height;
	}

	static void android_green(void)
	{
	gr_color(0xa4, 0xc6, 0x39, 255);
	}

	static void redraw_screen(struct charger *charger)
	{
	int surf_height;
	int surf_width;
	int x;
	int y = 0;
	int batt_cap;
	int ret;
	char cap_string[128];
	char cap_path[256];

	clear_screen();

	if (charger->surf_charging) {
	surf_width = gr_get_width(charger->surf_charging);
	surf_height = gr_get_height(charger->surf_charging);
	x = (gr_fb_width() - surf_width) / 2 ;
	y = (gr_fb_height() - surf_height) / 2 ;

	gr_blit(charger->surf_charging, 0, 0,
	surf_width, surf_height,
	x, y);
	y += surf_height;
	} else {
	android_green();
	y = draw_text("Charging!", -1, -1);
	}

	cap_string[0] = '\0';
	if (charger->battery) {
	ret = snprintf(cap_path, sizeof(cap_path),
	"/sys/class/power_supply/%s/capacity",
	charger->battery->name);
	if (ret <= 0)
	goto done;
	ret = read_file_int(cap_path, &batt_cap);
	if (ret >= 0)
	snprintf(cap_string, sizeof(cap_string), "%d/100", batt_cap);
	}

	if (cap_string[0] == '\0')
	snprintf(cap_string, sizeof(cap_string), "?\?/100");

	y += 25;
	android_green();
	draw_text(cap_string, -1, y);

	done:
	gr_flip();
	}

	static void update_screen_state(struct charger *charger, int64_t now,
	bool force)
	{
	if (!force && ((now < charger->next_screen_transition) \|\|
	(charger->next_screen_transition == -1)))
	return;

	if (!charger->screen_on)
	charger->next_screen_transition = now + SCREEN_ON_TIME;
	else
	charger->next_screen_transition = -1;
	charger->screen_on = !charger->screen_on;

	gr_fb_blank(!charger->screen_on);
	if (charger->screen_on)
	redraw_screen(charger);
	LOGV("[%lld] screen %s\n", now, charger->screen_on ? "on" : "off");
	}

	static void update_input_state(struct charger *charger,
	struct input_event *ev,
	int64_t now)
	{
	int down = !!ev->value;

	if (ev->type != EV_KEY \|\| ev->code > KEY_MAX)
	return;

	/* only record the down even timestamp, as the amount
	* of time the key spent not being pressed is not useful */
	if (down)
	charger->keys[ev->code].timestamp = now;
	charger->keys[ev->code].down = down;
	charger->keys[ev->code].pending = true;
	if (down) {
	LOGV("[%lld] key[%d] down\n", now, ev->code);
	} else {
	int64_t duration = now - charger->keys[ev->code].timestamp;
	int64_t secs = duration / 1000;
	int64_t msecs = duration - secs * 1000;
	LOGV("[%lld] key[%d] up (was down for %lld.%lldsec)\n", now,
	ev->code, secs, msecs);
	}
	}

	static void set_next_key_check(struct charger *charger,
	struct key_state *key,
	int64_t timeout)
	{
	int64_t then = key->timestamp + timeout;

	if (charger->next_key_check == -1 \|\| then < charger->next_key_check)
	charger->next_key_check = then;
	}

	static void process_key(struct charger *charger, int code, int64_t now)
	{
	struct key_state *key = &charger->keys[code];
	int64_t next_key_check;

	if (code == KEY_POWER) {
	if (key->down) {
	int64_t reboot_timeout = key->timestamp + POWER_ON_KEY_TIME;
	if (now >= reboot_timeout) {
	LOGI("[%lld] rebooting\n", now);
	android_reboot(ANDROID_RB_RESTART, 0, 0);
	} else {
	/* if the key is pressed but timeout hasn't expired,
	* make sure we wake up at the right-ish time to check
	*/
	set_next_key_check(charger, key, POWER_ON_KEY_TIME);
	}
	} else {
	/* if the power key got released, force screen state cycle */
	if (key->pending)
	update_screen_state(charger, now, true);
	}
	}

	key->pending = false;
	}

	static void handle_input_state(struct charger *charger, int64_t now)
	{
	process_key(charger, KEY_POWER, now);

	if (charger->next_key_check != -1 && now > charger->next_key_check)
	charger->next_key_check = -1;
	}

	static void handle_power_supply_state(struct charger *charger, int64_t now)
	{
	if (charger->num_supplies_online == 0) {
	if (charger->next_pwr_check == -1) {
	charger->next_pwr_check = now + UNPLUGGED_SHUTDOWN_TIME;
	LOGI("[%lld] device unplugged: shutting down in %lld (@ %lld)\n",
	now, UNPLUGGED_SHUTDOWN_TIME, charger->next_pwr_check);
	} else if (now >= charger->next_pwr_check) {
	LOGI("[%lld] shutting down\n", now);
	android_reboot(ANDROID_RB_POWEROFF, 0, 0);
	} else {
	/* otherwise we already have a shutdown timer scheduled */
	}
	} else {
	/* online supply present, reset shutdown timer if set */
	if (charger->next_pwr_check != -1) {
	LOGI("[%lld] device plugged in: shutdown cancelled\n", now);
	update_screen_state(charger, now, true);
	}
	charger->next_pwr_check = -1;
	}
	}

	static void wait_next_event(struct charger *charger, int64_t now)
	{
	int64_t next_event = INT64_MAX;
	int64_t timeout;
	struct input_event ev;
	int ret;

	LOGV("[%lld] next screen: %lld next key: %lld next pwr: %lld\n", now,
	charger->next_screen_transition, charger->next_key_check,
	charger->next_pwr_check);

	/* TODO: right now it's just screen on/off and keys, but later I'm sure
	* there will be animations */
	if (charger->next_screen_transition != -1)
	next_event = charger->next_screen_transition;
	if (charger->next_key_check != -1 && charger->next_key_check < next_event)
	next_event = charger->next_key_check;
	if (charger->next_pwr_check != -1 && charger->next_pwr_check < next_event)
	next_event = charger->next_pwr_check;

	if (next_event != -1 && next_event != INT64_MAX)
	timeout = max(0, next_event - now);
	else
	timeout = -1;
	LOGV("[%lld] blocking (%lld)\n", now, timeout);
	ret = ev_wait((int)timeout);
	if (!ret)
	ev_dispatch();
	}

	static int input_callback(int fd, short revents, void *data)
	{
	struct charger *charger = data;
	struct input_event ev;
	int ret;

	ret = ev_get_input(fd, revents, &ev);
	if (ret)
	return -1;
	update_input_state(charger, &ev, curr_time_ms());
	return 0;
	}

	static void event_loop(struct charger *charger)
	{
	int ret;

	while (true) {
	int64_t now = curr_time_ms();

	LOGV("[%lld] event_loop()\n", now);
	handle_input_state(charger, now);
	update_screen_state(charger, now, false);
	handle_power_supply_state(charger, now);

	wait_next_event(charger, now);
	}
	}

	int main(int argc, char **argv)
	{
	int ret;
	struct charger *charger = &charger_state;
	int64_t now = curr_time_ms() - 1;
	int fd;

	list_init(&charger->supplies);

	klog_init();
	klog_set_level(CHARGER_KLOG_LEVEL);

	gr_init();
	gr_font_size(&char_width, &char_height);

	ev_init(input_callback, charger);

	fd = uevent_open_socket(64*1024, true);
	if (fd >= 0) {
	fcntl(fd, F_SETFL, O_NONBLOCK);
	ev_add_fd(fd, uevent_callback, charger);
	}
	charger->uevent_fd = fd;
	coldboot(charger, "/sys/class/power_supply", "add");

	ret = res_create_surface("charging", &charger->surf_charging);
	if (ret < 0) {
	LOGE("Cannot load image\n");
	charger->surf_charging = NULL;
	}

	gr_fb_blank(true);

	charger->next_screen_transition = now - 1;
	charger->next_key_check = -1;
	charger->next_pwr_check = -1;
	charger->screen_on = false;

	event_loop(charger);

	return 0;
	}