wmbattery/acpi.c

   1 /*
   2  * A not-yet-general-purpose ACPI library, by Joey Hess <joey@kitenet.net>
   3  */
   4
   5 #include <unistd.h>
   6 #include <stdlib.h>
   7 #include <stdio.h>
   8 #include <sys/types.h>
   9 #include <dirent.h>
  10 #include <string.h>
  11 #include <fnmatch.h>
  12 #ifdef ACPI_APM
  13 #include "apm.h"
  14 #endif
  15 #include <sys/types.h>
  16 #include <sys/stat.h>
  17 #include <fcntl.h>
  18
  19 #include "acpi.h"
  20
  21 #define SYSFS_PATH "/sys/class/power_supply"
  22 #define ACPI_MAXITEM 8
  23
  24 int acpi_batt_count = 0;
  25 /* Filenames of the battery info files for each system battery. */
  26 char acpi_batt_info[ACPI_MAXITEM][128];
  27 /* Filenames of the battery status files for each system battery. */
  28 char acpi_batt_status[ACPI_MAXITEM][128];
  29 /* Stores battery capacity, or 0 if the battery is absent. */
  30 int acpi_batt_capacity[ACPI_MAXITEM];
  31
  32 int acpi_ac_count = 0;
  33 char acpi_ac_adapter_info[ACPI_MAXITEM][128];
  34 char acpi_ac_adapter_status[ACPI_MAXITEM][128];
  35
  36 char *acpi_labels[] = {
  37         "uevent",
  38         "status",
  39         "Battery",
  40         "Mains",
  41         "POWER_SUPPLY_CAPACITY=",
  42         "POWER_SUPPLY_??????_FULL_DESIGN=", /* CHARGE or ENERGY */
  43         "POWER_SUPPLY_PRESENT=",
  44         "POWER_SUPPLY_??????_NOW=",
  45         "POWER_SUPPLY_CURRENT_NOW=",
  46         "POWER_SUPPLY_STATUS=",
  47 #if ACPI_THERMAL
  48         "thermal_zone",
  49 #endif
  50         "POWER_SUPPLY_ONLINE=",
  51         "POWER_SUPPLY_??????_FULL=",
  52         NULL
  53 };
  54
  55 #if ACPI_THERMAL
  56 int acpi_thermal_count = 0;
  57 char acpi_thermal_info[ACPI_MAXITEM][128];
  58 char acpi_thermal_status[ACPI_MAXITEM][128];
  59 #endif
  60
  61 /* Read in an entire ACPI proc file (well, the first 1024 bytes anyway), and
  62  * return a statically allocated array containing it. */
  63 inline char *get_acpi_file(const char *file)
  64 {
  65         int fd;
  66         int end;
  67         static char buf[1024];
  68         fd = open(file, O_RDONLY);
  69         if (fd == -1)
  70                 return NULL;
  71         end = read(fd, buf, sizeof(buf));
  72         buf[end-1] = '\0';
  73         close(fd);
  74         return buf;
  75 }
  76
  77 int strmcmp(const char *s1, const char *s2)
  78 {
  79         for (; (*s1 == *s2) || (*s2 == '?'); s1++, s2++) {
  80                 if (*s1 == '\0')
  81                         return 0;
  82         }
  83         if (*s2 == '\0')
  84                 return 0;
  85         else
  86                 return 1;
  87 }
  88
  89 /* Given a buffer holding an acpi file, searches for the given key in it,
  90  * and returns the numeric value. 0 is returned on failure. */
  91 inline int scan_acpi_num(const char *buf, const char *key)
  92 {
  93         char *ptr;
  94         int ret = 0;
  95
  96         do {
  97                 ptr = strchr(buf, '\n');
  98                 if (!strmcmp(buf, key)) {
  99                         ptr = strchr(buf, '=');
 100                         if (ptr) {
 101                                 sscanf(ptr + 1, "%d", &ret);
 102                                 return ret;
 103                         } else {
 104                                 return 0;
 105                         }
 106                 }
 107                 if (ptr)
 108                         ptr++;
 109                 buf = ptr;
 110         } while (buf != NULL);
 111         return 0;
 112 }
 113
 114 /* Given a buffer holding an acpi file, searches for the given key in it,
 115  * and returns its value in a statically allocated string. */
 116 inline char *scan_acpi_value(const char *buf, const char *key)
 117 {
 118         char *ptr;
 119         static char ret[256];
 120
 121         do {
 122                 ptr = strchr(buf, '\n');
 123                 if (!strmcmp(buf, key)) {
 124                         ptr = strchr(buf, '=');
 125                         if (ptr) {
 126                                 if (sscanf(ptr + 1, "%255s", ret) == 1)
 127                                         return ret;
 128                                 else
 129                                         return NULL;
 130                         } else {
 131                                 return NULL;
 132                         }
 133                 }
 134                 if (ptr)
 135                         ptr++;
 136                 buf = ptr;
 137         } while (buf != NULL);
 138         return NULL;
 139 }
 140
 141 /* Read an ACPI proc file, pull out the requested piece of information, and
 142  * return it (statically allocated string). Returns NULL on error, This is
 143  * the slow, dumb way, fine for initialization or if only one value is needed
 144  * from a file, slow if called many times. */
 145 char *get_acpi_value(const char *file, const char *key)
 146 {
 147         char *buf = get_acpi_file(file);
 148         if (!buf)
 149                 return NULL;
 150         return scan_acpi_value(buf, key);
 151 }
 152
 153 /* Returns the last full charge capacity of a battery.
 154  */
 155 int get_acpi_batt_capacity(int battery)
 156 {
 157         char *s;
 158
 159         s = get_acpi_value(acpi_batt_info[battery], acpi_labels[label_last_full_capacity]);
 160         if (s == NULL)
 161                 return 0;
 162         else
 163                 return atoi(s);
 164 }
 165
 166 /* Comparison function for qsort. */
 167 int _acpi_compare_strings(const void *a, const void *b)
 168 {
 169         const char **pa = (const char **)a;
 170         const char **pb = (const char **)b;
 171         return strcasecmp((const char *)*pa, (const char *)*pb);
 172 }
 173
 174 /* Find something (batteries, ac adpaters, etc), and set up a string array
 175  * to hold the paths to info and status files of the things found.
 176  * Returns the number of items found. */
 177 int find_items(char *itemname, char infoarray[ACPI_MAXITEM][128],
 178                 char statusarray[ACPI_MAXITEM][128])
 179 {
 180         DIR *dir;
 181         struct dirent *ent;
 182         int num_devices = 0;
 183         int i;
 184         char **devices = malloc(ACPI_MAXITEM * sizeof(char *));
 185
 186         char pathname[128];
 187
 188         sprintf(pathname, SYSFS_PATH);
 189
 190         dir = opendir(pathname);
 191         if (dir == NULL)
 192                 return 0;
 193         while ((ent = readdir(dir))) {
 194                 char filename[128];
 195                 char buf[1024];
 196
 197                 if (!strcmp(".", ent->d_name) ||
 198                     !strcmp("..", ent->d_name))
 199                         continue;
 200
 201                 snprintf(filename, sizeof(filename), SYSFS_PATH "/%s/type", ent->d_name);
 202                 int fd = open(filename, O_RDONLY);
 203                 if (fd != -1) {
 204                         int end = read(fd, buf, sizeof(buf));
 205                         buf[end-1] = '\0';
 206                         close(fd);
 207                         if (strstr(buf, itemname) != buf)
 208                                 continue;
 209                 }
 210
 211                 devices[num_devices] = strdup(ent->d_name);
 212                 num_devices++;
 213                 if (num_devices >= ACPI_MAXITEM)
 214                         break;
 215         }
 216         closedir(dir);
 217
 218         /* Sort, since readdir can return in any order. /sys/ does
 219          * sometimes list BAT1 before BAT0. */
 220         qsort(devices, num_devices, sizeof(char *), _acpi_compare_strings);
 221
 222         for (i = 0; i < num_devices; i++) {
 223                 snprintf(infoarray[i], sizeof(infoarray[i]), SYSFS_PATH "/%s/%s", devices[i],
 224                         acpi_labels[label_info]);
 225                 snprintf(statusarray[i], sizeof(statusarray[i]), SYSFS_PATH "/%s/%s", devices[i],
 226                         acpi_labels[label_status]);
 227                 free(devices[i]);
 228         }
 229
 230         return num_devices;
 231 }
 232
 233 /* Find batteries, return the number, and set acpi_batt_count to it as well. */
 234 int find_batteries(void)
 235 {
 236         int i;
 237         acpi_batt_count = find_items(acpi_labels[label_battery], acpi_batt_info, acpi_batt_status);
 238         for (i = 0; i < acpi_batt_count; i++)
 239                 acpi_batt_capacity[i] = get_acpi_batt_capacity(i);
 240         return acpi_batt_count;
 241 }
 242
 243 /* Find AC power adapters, return the number found, and set acpi_ac_count to it
 244  * as well. */
 245 int find_ac_adapters(void)
 246 {
 247         acpi_ac_count = find_items(acpi_labels[label_ac_adapter], acpi_ac_adapter_info, acpi_ac_adapter_status);
 248         return acpi_ac_count;
 249 }
 250
 251 #if ACPI_THERMAL
 252 /* Find thermal information sources, return the number found, and set
 253  * thermal_count to it as well. */
 254 int find_thermal(void)
 255 {
 256         acpi_thermal_count = find_items(acpi_labels[label_thermal], acpi_thermal_info, acpi_thermal_status);
 257         return acpi_thermal_count;
 258 }
 259 #endif
 260
 261 /* Returns true if the system is on ac power. Call find_ac_adapters first. */
 262 int on_ac_power(void)
 263 {
 264         int i;
 265         for (i = 0; i < acpi_ac_count; i++) {
 266                 char *online = get_acpi_value(acpi_ac_adapter_info[i], acpi_labels[label_ac_state]);
 267                 if (online && atoi(online))
 268                         return 1;
 269                 else
 270                         return 0;
 271         }
 272         return 0;
 273 }
 274
 275 /* See if we have ACPI support and check version. Also find batteries and
 276  * ac power adapters. */
 277 int acpi_supported(void)
 278 {
 279         char *version;
 280         DIR *dir;
 281         int num;
 282
 283         dir = opendir(SYSFS_PATH);
 284         if (!dir)
 285                 return 0;
 286         closedir(dir);
 287
 288         /* If kernel is 2.6.21 or newer, version is in
 289            /sys/module/acpi/parameters/acpica_version */
 290
 291         version = get_acpi_file("/sys/module/acpi/parameters/acpica_version");
 292         if (version == NULL)
 293                 return 0;
 294         num = atoi(version);
 295         if (num < ACPI_VERSION) {
 296                 fprintf(stderr, "ACPI subsystem %s too is old, consider upgrading to %i.\n",
 297                                 version, ACPI_VERSION);
 298                 return 0;
 299         }
 300
 301         find_batteries();
 302         find_ac_adapters();
 303 #if ACPI_THERMAL
 304         find_thermal();
 305 #endif
 306
 307         return 1;
 308 }
 309
 310 #ifdef ACPI_APM
 311 /* Read ACPI info on a given power adapter and battery, and fill the passed
 312  * apm_info struct. */
 313 int acpi_read(int battery, apm_info *info)
 314 {
 315         char *buf, *state;
 316
 317         if (acpi_batt_count == 0) {
 318                 info->battery_percentage = 0;
 319                 info->battery_time = 0;
 320                 info->battery_status = BATTERY_STATUS_ABSENT;
 321                 acpi_batt_capacity[battery] = 0;
 322                 /* Where else would the power come from, eh? ;-) */
 323                 info->ac_line_status = 1;
 324                 return 0;
 325         }
 326
 327         /* Internally it's zero indexed. */
 328         battery--;
 329
 330         buf = get_acpi_file(acpi_batt_info[battery]);
 331         if (buf == NULL) {
 332                 fprintf(stderr, "unable to read %s\n", acpi_batt_info[battery]);
 333                 perror("read");
 334                 exit(1);
 335         }
 336
 337         info->ac_line_status = 0;
 338         info->battery_flags = 0;
 339         info->using_minutes = 1;
 340
 341         /* Work out if the battery is present, and what percentage of full
 342          * it is and how much time is left. */
 343         if (strcmp(scan_acpi_value(buf, acpi_labels[label_present]), "1") == 0) {
 344                 int pcap = scan_acpi_num(buf, acpi_labels[label_remaining_capacity]);
 345                 int rate = scan_acpi_num(buf, acpi_labels[label_present_rate]);
 346                 if (rate) {
 347                         /* time remaining = (current_capacity / discharge rate) */
 348                         info->battery_time = (float) pcap / (float) rate * 60;
 349                 } else {
 350                         char *rate_s = scan_acpi_value(buf, acpi_labels[label_present_rate]);
 351                         if (!rate_s) {
 352                                 /* Time remaining unknown. */
 353                                 info->battery_time = 0;
 354                         } else {
 355                                 /* a zero or unknown in the file; time
 356                                  * unknown so use a negative one to
 357                                  * indicate this */
 358                                 info->battery_time = -1;
 359                         }
 360                 }
 361
 362                 state = scan_acpi_value(buf, acpi_labels[label_charging_state]);
 363                 if (state) {
 364                         if (state[0] == 'D') { /* discharging */
 365                                 info->battery_status = BATTERY_STATUS_CHARGING;
 366                                 /* Expensive ac power check used here
 367                                  * because AC power might be on even if a
 368                                  * battery is discharging in some cases. */
 369                                 info->ac_line_status = on_ac_power();
 370                         } else if (state[0] == 'C' && state[1] == 'h') { /* charging */
 371                                 info->battery_status = BATTERY_STATUS_CHARGING;
 372                                 info->ac_line_status = 1;
 373                                 info->battery_flags = info->battery_flags | BATTERY_FLAGS_CHARGING;
 374                                 if (rate)
 375                                         info->battery_time = -1 * (float) (acpi_batt_capacity[battery] - pcap) /
 376                                                 (float) rate * 60;
 377                                 else
 378                                         info->battery_time = 0;
 379                                 if (abs(info->battery_time) < 0.5)
 380                                         info->battery_time = 0;
 381                         } else if (state[0] == 'F') { /* full */
 382                                 /* charged, on ac power */
 383                                 info->battery_status = BATTERY_STATUS_HIGH;
 384                                 info->ac_line_status = 1;
 385                         } else if (state[0] == 'C') { /* not charging, so must be critical */
 386                                 info->battery_status = BATTERY_STATUS_CRITICAL;
 387                                 /* Expensive ac power check used here
 388                                  * because AC power might be on even if a
 389                                  * battery is critical in some cases. */
 390                                 info->ac_line_status = on_ac_power();
 391                         } else if (state[0] == 'U') { /* unknown */
 392                                 info->ac_line_status = on_ac_power();
 393                                 int current = scan_acpi_num(buf, acpi_labels[label_present_rate]);
 394                                 if (info->ac_line_status) {
 395                                         if (current == 0)
 396                                                 info->battery_status = BATTERY_STATUS_HIGH;
 397                                         else
 398                                                 info->battery_status = BATTERY_STATUS_CHARGING;
 399                                 } else {
 400                                         info->battery_status = BATTERY_STATUS_CHARGING;
 401                                 }
 402                         } else {
 403                                 fprintf(stderr, "unknown battery state: %s\n", state);
 404                         }
 405                 } else {
 406                         /* Battery state unknown. */
 407                         info->battery_status = BATTERY_STATUS_ABSENT;
 408                 }
 409
 410                 if (acpi_batt_capacity[battery] == 0) {
 411                         /* The battery was absent, and now is present.
 412                          * Well, it might be a different battery. So
 413                          * re-probe the battery. */
 414                         /* NOTE that this invalidates buf. No accesses of
 415                          * buf below this point! */
 416                         acpi_batt_capacity[battery] = get_acpi_batt_capacity(battery);
 417                 } else if (pcap > acpi_batt_capacity[battery]) {
 418                         /* Battery is somehow charged to greater than max
 419                          * capacity. Rescan for a new max capacity. */
 420                         find_batteries();
 421                 }
 422
 423                 if (pcap && acpi_batt_capacity[battery]) {
 424                         info->battery_percentage = 100 * pcap / acpi_batt_capacity[battery];
 425                         if (info->battery_percentage > 100)
 426                                 info->battery_percentage = 100;
 427                 } else {
 428                         info->battery_percentage = -1;
 429                 }
 430
 431         } else {
 432                 info->battery_percentage = 0;
 433                 info->battery_time = 0;
 434                 info->battery_status = BATTERY_STATUS_ABSENT;
 435                 acpi_batt_capacity[battery] = 0;
 436                 if (acpi_batt_count == 0) {
 437                         /* Where else would the power come from, eh? ;-) */
 438                         info->ac_line_status = 1;
 439                 } else {
 440                         /* Expensive ac power check. */
 441                         info->ac_line_status = on_ac_power();
 442                 }
 443         }
 444
 445         return 0;
 446 }
 447 #endif