wmbattery/upower.c

   1 /* Not particularly good interface to hal, for programs that used to use
   2  * apm.
   3  */
   4
   5 #include <stdio.h>
   6 #include <stdlib.h>
   7 #include <string.h>
   8 #include <unistd.h>
   9 #include <errno.h>
  10 #include <sys/types.h>
  11 #include <sys/socket.h>
  12 #include <sys/wait.h>
  13 #include <upower.h>
  14 #include "apm.h"
  15
  16 #define MAX_RETRIES 3
  17
  18 struct context {
  19         int current;
  20         int needed;
  21         guint state;
  22         int percentage;
  23         gboolean ac;
  24         int time;
  25 };
  26
  27 static void get_devinfo(gpointer device, gpointer result)
  28 {
  29         gboolean online;
  30         gdouble percentage;
  31         guint state;
  32         guint kind;
  33         gint64 time_to_empty;
  34         gint64 time_to_full;
  35         struct context *ctx = result;
  36
  37         g_object_get(G_OBJECT(device), "percentage", &percentage,
  38                 "online", &online,
  39                 "state", &state,
  40                 "kind", &kind,
  41                 "time-to-empty", &time_to_empty,
  42                 "time-to-full", &time_to_full,
  43                 NULL);
  44         if (kind == UP_DEVICE_KIND_BATTERY) {
  45                 if (ctx->current == ctx->needed) {
  46                         ctx->percentage = (int)percentage;
  47                         ctx->state = state;
  48                         if (time_to_empty)
  49                                 ctx->time = time_to_empty;
  50                         else
  51                                 ctx->time = time_to_full;
  52                 }
  53                 ctx->current++;
  54         } else if (kind == UP_DEVICE_KIND_LINE_POWER) {
  55                 ctx->ac |= online;
  56         }
  57 }
  58
  59 /* Fill the passed apm_info struct. */
  60 static int upower_read_child(int battery, apm_info *info)
  61 {
  62         UpClient * up;
  63         GPtrArray *devices = NULL;
  64
  65         up = up_client_new();
  66
  67         if (!up)
  68                 return -1;
  69
  70         #if !UP_CHECK_VERSION(0, 9, 99)
  71         /* Allow a battery that was not present before to appear. */
  72         up_client_enumerate_devices_sync(up, NULL, NULL);
  73         #endif
  74
  75         devices = up_client_get_devices(up);
  76
  77         if (!devices)
  78                 return -1;
  79
  80         info->battery_flags = 0;
  81         info->using_minutes = 0;
  82
  83         struct context ctx = {
  84                 .current = 0,
  85                 .needed = battery - 1,
  86                 .state = UP_DEVICE_STATE_UNKNOWN,
  87                 .percentage = -1,
  88                 .ac = FALSE,
  89                 .time = -1
  90         };
  91
  92         g_ptr_array_foreach(devices, &get_devinfo, &ctx);
  93
  94         info->ac_line_status = ctx.ac;
  95
  96         /* remaining_time and charge_level.percentage are not a mandatory
  97          * keys, so if not present, -1 will be returned */
  98         info->battery_time = ctx.time;
  99         info->battery_percentage = ctx.percentage;
 100         if (ctx.state == UP_DEVICE_STATE_DISCHARGING) {
 101                 info->battery_status = BATTERY_STATUS_CHARGING;
 102                 /* charge_level.warning and charge_level.low are not
 103                  * required to be available; this is good enough */
 104                 if (info->battery_percentage < 1)
 105                         info->battery_status = BATTERY_STATUS_CRITICAL;
 106                 else if (info->battery_percentage < 10)
 107                         info->battery_status = BATTERY_STATUS_LOW;
 108         } else if (info->ac_line_status && ctx.state == UP_DEVICE_STATE_CHARGING) {
 109                 info->battery_status = BATTERY_STATUS_CHARGING;
 110                 info->battery_flags = info->battery_flags | BATTERY_FLAGS_CHARGING;
 111         } else if (info->ac_line_status) {
 112                 /* Must be fully charged. */
 113                 info->battery_status = BATTERY_STATUS_HIGH;
 114         } else {
 115                 fprintf(stderr, "unknown battery state\n");
 116         }
 117
 118         if (ctx.percentage < 0) {
 119                 info->battery_percentage = 0;
 120                 info->battery_time = 0;
 121                 info->battery_status = BATTERY_STATUS_ABSENT;
 122         }
 123
 124         g_ptr_array_unref(devices);
 125         return 0;
 126 }
 127
 128 static int upower_read_work(int battery, apm_info *info)
 129 {
 130         int sp[2];
 131         int child;
 132         int status;
 133         ssize_t cv;
 134
 135         if (socketpair(AF_UNIX, SOCK_DGRAM, 0, sp) < 0) {
 136                 fprintf(stderr, "socketpair: %s", strerror(errno));
 137                 goto fail;
 138         }
 139
 140         child = fork();
 141         if (child < 0) {
 142                 fprintf(stderr, "fork: %s", strerror(errno));
 143                 goto fail_close;
 144         }
 145
 146         if (child == 0) {
 147                 /* child process does work, writes failure or result back to parent */
 148                 close(sp[0]);
 149                 status = upower_read_child(battery, info);
 150                 if (status < 0) {
 151                         cv = send(sp[1], &status, sizeof(status), 0);
 152                 }
 153                 else {
 154                         cv = send(sp[1], info, sizeof(*info), 0);
 155                 }
 156                 exit(cv < 0);
 157         }
 158         close(sp[1]);
 159
 160         child = waitpid(child, &status, 0);
 161         if (child < 0) {
 162                 fprintf(stderr, "waitpid: %s status=%d", strerror(errno), status);
 163                 goto fail_close0;
 164         }
 165
 166         cv = recv(sp[0], info, sizeof(*info), 0);
 167         if (cv < 0) {
 168                 fprintf(stderr, "recv: %s", strerror(errno));
 169                 goto fail_close0;
 170         }
 171         else if (cv == sizeof(status)) {
 172                 memcpy(&status, info, sizeof(status));
 173                 goto fail_close0;
 174         }
 175         else if (cv != sizeof(*info)) {
 176                 fprintf(stderr, "recv: unexpected size %zd", cv);
 177                 goto fail_close0;
 178         }
 179
 180         close(sp[0]);
 181         return 0;
 182
 183 fail_close:
 184         close(sp[1]);
 185 fail_close0:
 186         close(sp[0]);
 187 fail:
 188         return -1;
 189 }
 190
 191 int upower_supported(void)
 192 {
 193         apm_info info;
 194         return !(upower_read_work(1, &info) < 0);
 195 }
 196
 197
 198 int upower_read(int battery, apm_info *info)
 199 {
 200         static int retries = 0;
 201
 202         if (upower_read_work(battery, info) < 0) {
 203                 retries++;
 204                 if (retries < MAX_RETRIES)
 205                         return 0; /* fine immediately after hibernation */
 206                 else
 207                         return -1;
 208         }
 209
 210         retries = 0;
 211         return 0;
 212 }