libsysfs/sysfs_driver.c

   1 /*
   2  * sysfs_driver.c
   3  *
   4  * Driver utility functions for libsysfs
   5  *
   6  * Copyright (C) IBM Corp. 2003
   7  *
   8  *  This library is free software; you can redistribute it and/or
   9  *  modify it under the terms of the GNU Lesser General Public
  10  *  License as published by the Free Software Foundation; either
  11  *  version 2.1 of the License, or (at your option) any later version.
  12  *
  13  *  This library is distributed in the hope that it will be useful,
  14  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  16  *  Lesser General Public License for more details.
  17  *
  18  *  You should have received a copy of the GNU Lesser General Public
  19  *  License along with this library; if not, write to the Free Software
  20  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  21  *
  22  */
  23 #include "libsysfs.h"
  24 #include "sysfs.h"
  25
  26 static void sysfs_close_driver_device(void *device)
  27 {
  28         sysfs_close_device((struct sysfs_device *)device);
  29 }
  30
  31 /**
  32  * sysfs_close_driver: closes driver and deletes device lists too
  33  * @driver: driver to close
  34  */
  35 void sysfs_close_driver(struct sysfs_driver *driver)
  36 {
  37         if (driver != NULL) {
  38                 if (driver->devices != NULL)
  39                         dlist_destroy(driver->devices);
  40                 if (driver->directory != NULL)
  41                         sysfs_close_directory(driver->directory);
  42                 free(driver);
  43         }
  44 }
  45
  46 /**
  47  * open_driver_dir: Open the sysfs_directory for this driver
  48  * @driver: Driver whose directory to be opened
  49  * Returns 0 on success and 1 on failure
  50  */
  51 static int open_driver_dir(struct sysfs_driver *driver)
  52 {
  53         if (driver == NULL) {
  54                 errno = EINVAL;
  55                 return 1;
  56         }
  57         if (driver->directory == NULL) {
  58                 driver->directory = sysfs_open_directory(driver->path);
  59                 if (driver->directory == NULL) {
  60                         dprintf("Error opening driver directory at %s\n",
  61                                         driver->path);
  62                         return 1;
  63                 }
  64         }
  65         return 0;
  66 }
  67
  68 /**
  69  * alloc_driver: allocates and initializes driver
  70  * returns struct sysfs_driver with success and NULL with error.
  71  */
  72 static struct sysfs_driver *alloc_driver(void)
  73 {
  74         return (struct sysfs_driver *)calloc(1, sizeof(struct sysfs_driver));
  75 }
  76
  77 /**
  78  * sysfs_open_driver_path: opens and initializes driver structure
  79  * @path: path to driver directory
  80  * returns struct sysfs_driver with success and NULL with error
  81  */
  82 struct sysfs_driver *sysfs_open_driver_path(const unsigned char *path)
  83 {
  84         struct sysfs_driver *driver = NULL;
  85
  86         if (path == NULL) {
  87                 errno = EINVAL;
  88                 return NULL;
  89         }
  90         if ((sysfs_path_is_dir(path)) != 0) {
  91                 dprintf("Invalid path to driver: %s\n", path);
  92                 return NULL;
  93         }
  94         driver = alloc_driver();
  95         if (driver == NULL) {
  96                 dprintf("Error allocating driver at %s\n", path);
  97                 return NULL;
  98         }
  99         if ((sysfs_get_name_from_path(path, driver->name,
 100                                         SYSFS_NAME_LEN)) != 0) {
 101                 dprintf("Error getting driver name from path\n");
 102                 free(driver);
 103                 return NULL;
 104         }
 105         strcpy(driver->path, path);
 106         if ((sysfs_remove_trailing_slash(driver->path)) != 0) {
 107                 dprintf("Invalid path to driver %s\n", driver->path);
 108                 sysfs_close_driver(driver);
 109                 return NULL;
 110         }
 111
 112         return driver;
 113 }
 114
 115 /**
 116  * sysfs_get_driver_attributes: gets list of attributes for the given driver
 117  * @driver: sysfs_driver for which attributes are required
 118  * returns a dlist of attributes corresponding to the driver if present
 119  *      NULL otherwise
 120  */
 121 struct dlist *sysfs_get_driver_attributes(struct sysfs_driver *driver)
 122 {
 123         if (driver == NULL) {
 124                 errno = EINVAL;
 125                 return NULL;
 126         }
 127
 128         if (driver->directory == NULL) {
 129                 if ((open_driver_dir(driver)) == 1)
 130                         return NULL;
 131         }
 132         if (driver->directory->attributes == NULL) {
 133                 if ((sysfs_read_dir_attributes(driver->directory)) != 0)
 134                         return NULL;
 135         }
 136         return(driver->directory->attributes);
 137 }
 138
 139 /**
 140  * sysfs_refresh_driver_attributes: refreshes the driver's list of attributes
 141  * @driver: sysfs_driver whose attributes to refresh
 142  *
 143  * NOTE: Upon return, prior references to sysfs_attributes for this driver
 144  *              _may_ not be valid
 145  *
 146  * Returns list of attributes on success and NULL on failure
 147  */
 148 struct dlist *sysfs_refresh_driver_attributes(struct sysfs_driver *driver)
 149 {
 150         if (driver == NULL) {
 151                 errno = EINVAL;
 152                 return NULL;
 153         }
 154         if (driver->directory == NULL)
 155                 return (sysfs_get_driver_attributes(driver));
 156
 157         if ((sysfs_refresh_dir_attributes(driver->directory)) != 0) {
 158                 dprintf("Error refreshing driver attributes\n");
 159                 return NULL;
 160         }
 161         return (driver->directory->attributes);
 162 }
 163
 164 /**
 165  * sysfs_get_driver_attr: searches driver's attributes by name
 166  * @drv: driver to look through
 167  * @name: attribute name to get
 168  * returns sysfs_attribute reference on success or NULL with error
 169  */
 170 struct sysfs_attribute *sysfs_get_driver_attr(struct sysfs_driver *drv,
 171                                         const unsigned char *name)
 172 {
 173         struct dlist *attrlist = NULL;
 174
 175         if (drv == NULL) {
 176                 errno = EINVAL;
 177                 return NULL;
 178         }
 179
 180         attrlist = sysfs_get_driver_attributes(drv);
 181         if (attrlist != NULL)
 182                 return NULL;
 183
 184         return sysfs_get_directory_attribute(drv->directory,
 185                                                 (unsigned char *)name);
 186 }
 187
 188 /**
 189  * sysfs_get_driver_links: gets list of links from the given driver
 190  * @driver: sysfs_driver for which links list is required
 191  * returns a dlist of links corresponding to the driver if present
 192  *      NULL otherwise
 193  */
 194 struct dlist *sysfs_get_driver_links(struct sysfs_driver *driver)
 195 {
 196         if (driver == NULL) {
 197                 errno = EINVAL;
 198                 return NULL;
 199         }
 200         if (driver->directory == NULL) {
 201                 if ((open_driver_dir(driver)) == 1)
 202                         return NULL;
 203                 if ((sysfs_read_dir_links(driver->directory)) != 0)
 204                         return NULL;
 205         }
 206         return(driver->directory->links);
 207 }
 208
 209 /**
 210  * sysfs_get_driver_devices: open up the list of devices this driver supports
 211  * @driver: sysfs_driver for which devices are needed
 212  * Returns dlist of devices on SUCCESS or NULL with ERROR
 213  */
 214 struct dlist *sysfs_get_driver_devices(struct sysfs_driver *driver)
 215 {
 216         struct sysfs_link *curlink = NULL;
 217         struct sysfs_device *device = NULL;
 218
 219         if (driver == NULL) {
 220                 errno = EINVAL;
 221                 return NULL;
 222         }
 223
 224         if (driver->devices != NULL)
 225                 return (driver->devices);
 226
 227         if (driver->directory == NULL) {
 228                 if ((open_driver_dir(driver)) == 1)
 229                         return NULL;
 230                 if ((sysfs_read_dir_links(driver->directory)) != 0)
 231                         return NULL;
 232         }
 233         if (driver->directory->links != NULL) {
 234                 dlist_for_each_data(driver->directory->links, curlink,
 235                                                 struct sysfs_link) {
 236                         device = sysfs_open_device_path(curlink->target);
 237                         if (device == NULL) {
 238                                 dprintf("Error opening device at %s\n",
 239                                                 curlink->target);
 240                                 return NULL;
 241                         }
 242                         strcpy(device->driver_name, driver->name);
 243                         if (driver->devices == NULL)
 244                                 driver->devices = dlist_new_with_delete
 245                                                 (sizeof(struct sysfs_device),
 246                                                  sysfs_close_driver_device);
 247                         dlist_unshift(driver->devices, device);
 248                 }
 249         }
 250         return (driver->devices);
 251 }
 252
 253 /**
 254  * sysfs_refresh_driver_devices: Refreshes drivers list of devices
 255  * @driver: sysfs_driver whose devices list needs to be refreshed
 256  *
 257  * NOTE: Upon return from this function, prior sysfs_device references from
 258  *              this driver's list of devices _may_ not be valid
 259  *
 260  * Returns dlist of devices on success and NULL on failure
 261  */
 262 struct dlist *sysfs_refresh_driver_devices(struct sysfs_driver *driver)
 263 {
 264         if (driver == NULL) {
 265                 errno = EINVAL;
 266                 return NULL;
 267         }
 268
 269         if (driver->devices != NULL) {
 270                 dlist_destroy(driver->devices);
 271                 driver->devices = NULL;
 272         }
 273
 274         if (driver->directory == NULL)
 275                 return (sysfs_get_driver_devices(driver));
 276
 277         if ((sysfs_refresh_dir_links(driver->directory)) != 0) {
 278                 dprintf("Error refreshing driver links\n");
 279                 return NULL;
 280         }
 281
 282         return (sysfs_get_driver_devices(driver));
 283 }
 284
 285 /**
 286  * sysfs_get_driver_device: looks up a device from a list of driver's devices
 287  *      and returns its sysfs_device corresponding to it
 288  * @driver: sysfs_driver on which to search
 289  * @name: name of the device to search
 290  * Returns a sysfs_device if found, NULL otherwise
 291  */
 292 struct sysfs_device *sysfs_get_driver_device(struct sysfs_driver *driver,
 293                                 const unsigned char *name)
 294 {
 295         struct sysfs_device *device = NULL;
 296         struct dlist *devlist = NULL;
 297
 298         if (driver == NULL || name == NULL) {
 299                 errno = EINVAL;
 300                 return NULL;
 301         }
 302
 303         if (driver->devices == NULL) {
 304                 devlist = sysfs_get_driver_devices(driver);
 305                 if (devlist == NULL) {
 306                         dprintf("Error getting driver devices\n");
 307                         return NULL;
 308                 }
 309         }
 310         dlist_for_each_data(driver->devices, device, struct sysfs_device) {
 311                 if (!(strncmp(device->name, name, SYSFS_NAME_LEN)))
 312                         return device;
 313         }
 314         return NULL;
 315 }
 316
 317 /**
 318  * get_driver_path: looks up the bus the driver is on and builds path to
 319  *              the driver.
 320  * @bus: bus on which to search
 321  * @drv: driver to look for
 322  * @path: buffer to return path to driver
 323  * @psize: size of "path"
 324  * Returns 0 on success and -1 on error
 325  */
 326 static int get_driver_path(const unsigned char *bus,
 327                 const unsigned char *drv, unsigned char *path, size_t psize)
 328 {
 329         if (bus == NULL || drv == NULL || path == NULL) {
 330                 errno = EINVAL;
 331                 return -1;
 332         }
 333         if (sysfs_get_mnt_path(path, psize) != 0) {
 334                 dprintf("Error getting sysfs mount path\n");
 335                 return -1;
 336         }
 337         strcat(path, "/");
 338         strcat(path, SYSFS_BUS_NAME);
 339         strcat(path, "/");
 340         strcat(path, bus);
 341         strcat(path, "/");
 342         strcat(path, SYSFS_DRIVERS_NAME);
 343         strcat(path, "/");
 344         strcat(path, drv);
 345         return 0;
 346 }
 347
 348 /**
 349  * sysfs_open_driver_attr: read the user supplied driver attribute
 350  * @bus: bus on which to look
 351  * @drv: driver whose attribute has to be read
 352  * @attrib: Attribute to be read
 353  * Returns struct sysfs_attribute on success and NULL on failure
 354  *
 355  * NOTE:
 356  *      A call to sysfs_close_attribute() is required to close the
 357  *      attribute returned and to free memory
 358  */
 359 struct sysfs_attribute *sysfs_open_driver_attr(const unsigned char *bus,
 360                 const unsigned char *drv, const unsigned char *attrib)
 361 {
 362         struct sysfs_attribute *attribute = NULL;
 363         unsigned char path[SYSFS_PATH_MAX];
 364
 365         if (bus == NULL || drv == NULL || attrib == NULL) {
 366                 errno = EINVAL;
 367                 return NULL;
 368         }
 369
 370         memset(path, 0, SYSFS_PATH_MAX);
 371         if ((get_driver_path(bus, drv, path, SYSFS_PATH_MAX)) != 0) {
 372                 dprintf("Error getting to driver %s\n", drv);
 373                 return NULL;
 374         }
 375         strcat(path, "/");
 376         strcat(path, attrib);
 377         attribute = sysfs_open_attribute(path);
 378         if (attribute == NULL) {
 379                 dprintf("Error opening attribute %s for driver %s\n",
 380                                 attrib, drv);
 381                 return NULL;
 382         }
 383         if ((sysfs_read_attribute(attribute)) != 0) {
 384                 dprintf("Error reading attribute %s for driver %s\n",
 385                                 attrib, drv);
 386                 sysfs_close_attribute(attribute);
 387                 return NULL;
 388         }
 389         return attribute;
 390 }
 391
 392 /**
 393  * sysfs_open_driver: open driver by name, given its bus
 394  * @drv_name: Name of the driver
 395  * @bus_name: Name of the bus
 396  * Returns the sysfs_driver reference on success and NULL on failure
 397  */
 398 struct sysfs_driver *sysfs_open_driver(const unsigned char *drv_name,
 399                                 const unsigned char *bus_name)
 400 {
 401         unsigned char path[SYSFS_PATH_MAX];
 402         struct sysfs_driver *driver = NULL;
 403
 404         if (drv_name == NULL || bus_name == NULL) {
 405                 errno = EINVAL;
 406                 return NULL;
 407         }
 408
 409         memset(path, 0, SYSFS_PATH_MAX);
 410         if ((get_driver_path(bus_name, drv_name, path, SYSFS_PATH_MAX)) != 0) {
 411                 dprintf("Error getting to driver %s\n", drv_name);
 412                 return NULL;
 413         }
 414         driver = sysfs_open_driver_path(path);
 415         if (driver == NULL) {
 416                 dprintf("Error opening driver at %s\n", path);
 417                 return NULL;
 418         }
 419         return driver;
 420 }
 421