Logo Search packages:      
Sourcecode: hal version File versions

sysfs_class.c

/*
 * sysfs_class.c
 *
 * Generic class utility functions for libsysfs
 *
 * Copyright (C) IBM Corp. 2003
 *
 *  This library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Lesser General Public
 *  License as published by the Free Software Foundation; either
 *  version 2.1 of the License, or (at your option) any later version.
 *
 *  This library is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 *  Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public
 *  License along with this library; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 *
 */
#include "libsysfs.h"
#include "sysfs.h"

static void sysfs_close_cls_dev(void *dev)
{
      sysfs_close_class_device((struct sysfs_class_device *)dev);
}

/**
 * class_name_equal: compares class_devices' name
 * @a: class_name looking for
 * @b: sysfs_class_device being compared
 */
static int class_name_equal(void *a, void *b)
{
      if (a == NULL || b == NULL)
            return 0;

      if (strcmp(((char *)a), ((struct sysfs_class_device *)b)->name) == 0)
            return 1;

      return 0;
}

/**
 * sysfs_close_class_device: closes a single class device.
 * @dev: class device to close.
 */
void sysfs_close_class_device(struct sysfs_class_device *dev)
{
      if (dev != NULL) {
            if (dev->directory != NULL)
                  sysfs_close_directory(dev->directory);
            if (dev->sysdevice != NULL)
                  sysfs_close_device(dev->sysdevice);
            if (dev->driver != NULL)
                  sysfs_close_driver(dev->driver);
            if (dev->parent != NULL)
                  sysfs_close_class_device(dev->parent);
            free(dev);
      }
}

/**
 * sysfs_close_class: close single class
 * @cls: class structure
 */
void sysfs_close_class(struct sysfs_class *cls)
{
      if (cls != NULL) {
            if (cls->directory != NULL)
                  sysfs_close_directory(cls->directory);
            if (cls->devices != NULL) 
                  dlist_destroy(cls->devices);
            free(cls);
      }
}

/**
 * alloc_class_device: mallocs and initializes new class device struct.
 * returns sysfs_class_device or NULL.
 */
static struct sysfs_class_device *alloc_class_device(void)
{
      return (struct sysfs_class_device *)
                        calloc(1, sizeof(struct sysfs_class_device));
}

/**
 * alloc_class: mallocs new class structure
 * returns sysfs_class struct or NULL
 */
static struct sysfs_class *alloc_class(void)
{
      return (struct sysfs_class *)calloc(1, sizeof(struct sysfs_class));
}

/** 
 * set_classdev_classname: Grabs classname from path
 * @cdev: class device to set
 * Returns nothing
 */
static void set_classdev_classname(struct sysfs_class_device *cdev)
{
      char *c = NULL, *e = NULL;
      int count = 0;

      c = strstr(cdev->path, SYSFS_CLASS_NAME);
      if (c == NULL) {
            c = strstr(cdev->path, SYSFS_BLOCK_NAME);
      } else {
            c = strstr(c, "/");
      }

      if (c == NULL)
            safestrcpy(cdev->classname, SYSFS_UNKNOWN);
      else {
            if (*c == '/')
                  c++;
            e = c;
            while (e != NULL && *e != '/' && *e != '\0') {
                  e++;
                  count++;
            }
            strncpy(cdev->classname, c, count);
      }
}

/**
 * sysfs_open_class_device_path: Opens and populates class device
 * @path: path to class device.
 * returns struct sysfs_class_device with success and NULL with error.
 */
struct sysfs_class_device *sysfs_open_class_device_path(const char *path)
{
      struct sysfs_class_device *cdev = NULL;

      if (path == NULL) {
            errno = EINVAL;
            return NULL;
      }
      if ((sysfs_path_is_dir(path)) != 0) {
            dprintf("%s is not a valid path to a class device\n", path);
            return NULL;
      }
      cdev = alloc_class_device();
      if (cdev == NULL) {
            dprintf("calloc failed\n");
            return NULL;
      }
      if ((sysfs_get_name_from_path(path, cdev->name, SYSFS_NAME_LEN)) != 0) {
            errno = EINVAL;
            dprintf("Error getting class device name\n");
            sysfs_close_class_device(cdev);
            return NULL;
      }

      safestrcpy(cdev->path, path);
      if ((sysfs_remove_trailing_slash(cdev->path)) != 0) {
            dprintf("Invalid path to class device %s\n", cdev->path);
            sysfs_close_class_device(cdev);
            return NULL;
      }
      set_classdev_classname(cdev);

      return cdev;
}

/**
 * sysfs_get_class_devices: gets all devices for class
 * @cls: class to get devices for
 * returns dlist of class_devices with success and NULL with error
 */
struct dlist *sysfs_get_class_devices(struct sysfs_class *cls)
{
      struct sysfs_class_device *dev = NULL;
      struct sysfs_directory *cur = NULL;

      if (cls == NULL) {
            errno = EINVAL;
            return NULL;
      }

      if (cls->devices != NULL) 
            return cls->devices;

      if (cls->directory == NULL) {
            cls->directory = sysfs_open_directory(cls->path);
            if (cls->directory == NULL) 
                  return NULL;
      }

      if ((sysfs_read_dir_subdirs(cls->directory)) != 0) 
            return NULL;

      if (cls->directory->subdirs != NULL) {
            dlist_for_each_data(cls->directory->subdirs, cur, 
                                    struct sysfs_directory) {
                  dev = sysfs_open_class_device_path(cur->path);
                  if (dev == NULL) {
                        dprintf("Error opening device at %s\n",   
                                                cur->path);
                        continue;
                  }
                  if (cls->devices == NULL)
                        cls->devices = dlist_new_with_delete
                              (sizeof(struct sysfs_class_device),
                                          sysfs_close_cls_dev);
                  dlist_unshift_sorted(cls->devices, dev, sort_list);
            }
      }
      return cls->devices;
}

/**
 * sysfs_open_class: opens specific class and all its devices on system
 * returns sysfs_class structure with success or NULL with error.
 */
struct sysfs_class *sysfs_open_class(const char *name)
{
      struct sysfs_class *cls = NULL;
      char classpath[SYSFS_PATH_MAX];

      if (name == NULL) {
            errno = EINVAL;
            return NULL;
      }

      memset(classpath, 0, SYSFS_PATH_MAX);
        if ((sysfs_get_mnt_path(classpath, SYSFS_PATH_MAX)) != 0) {
                dprintf("Sysfs not supported on this system\n");
                return NULL;
        }

      /* 
       * We shall now treat "block" also as a class. Hence, check here
       * if "name" is "block" and proceed accordingly
       */
      if (strcmp(name, SYSFS_BLOCK_NAME) == 0) {
            safestrcat(classpath, "/");
            safestrcat(classpath, SYSFS_BLOCK_NAME);
      } else {
            safestrcat(classpath, "/");
            safestrcat(classpath, SYSFS_CLASS_NAME);
            safestrcat(classpath, "/");
            safestrcat(classpath, name);
      }
      if ((sysfs_path_is_dir(classpath)) != 0) {
            dprintf("Class %s not found on the system\n", name);
            return NULL;
      }

      cls = alloc_class();
      if (cls == NULL) {
            dprintf("calloc failed\n");
            return NULL;
      }
      safestrcpy(cls->name, name);  
      safestrcpy(cls->path, classpath);
      if ((sysfs_remove_trailing_slash(cls->path)) != 0) {
            dprintf("Invalid path to class device %s\n", cls->path);
            sysfs_close_class(cls);
            return NULL;
      }
      
      return cls;
}

/**
 * sysfs_get_class_device: Get specific class device using the device's id
 * @class: class to find device on
 * @name: class name of the device
 */ 
struct sysfs_class_device *sysfs_get_class_device(struct sysfs_class *cls,
                              char *name)
{
      if (cls == NULL || name == NULL) {
            errno = EINVAL;
            return NULL;
      }

      if (cls->devices == NULL) {
            cls->devices = sysfs_get_class_devices(cls);
            if (cls->devices == NULL) 
                  return NULL;
      }
      return (struct sysfs_class_device *)dlist_find_custom(cls->devices,
                  name, class_name_equal);
}

/**
 * sysfs_get_classdev_device: returns the sysfs_device corresponding to
 *          sysfs_class_device, if present
 * @clsdev: class device whose sysfs_device is required
 * Returns sysfs_device on success, NULL on error or if device is not
 * implemented
 */ 
struct sysfs_device *sysfs_get_classdev_device
                  (struct sysfs_class_device *clsdev)
{
      struct sysfs_link *devlink = NULL;
      char devpath[SYSFS_PATH_MAX];
      
      if (clsdev == NULL) {
            errno = EINVAL;
            return NULL;
      }
      safestrcpy(devpath, clsdev->path);
      safestrcat(devpath, "/device");
      if ((sysfs_path_is_link(devpath)) != 0) {
            if (clsdev->sysdevice != NULL) {
                  sysfs_close_device(clsdev->sysdevice);
                  clsdev->sysdevice = NULL;
            }
            return NULL;
      }
      
      if (clsdev->directory == NULL) {
            clsdev->directory = sysfs_open_directory(clsdev->path);
            if (clsdev->directory == NULL)
                  return NULL;
      }
      devlink = sysfs_get_directory_link(clsdev->directory, "device");
      if (devlink == NULL) {
            if (clsdev->sysdevice != NULL) {
                  dprintf("Device link no longer exists\n");
                  sysfs_close_device(clsdev->sysdevice);
                  clsdev->sysdevice = NULL;
            }
            return NULL;
      }

      if (clsdev->sysdevice != NULL) {
            if (!strncmp(devlink->target, clsdev->sysdevice->path,
                                    SYSFS_PATH_MAX)) 
                  /* sysdevice hasn't changed */
                  return (clsdev->sysdevice);
            else 
                  /* come here only if the device link for has changed */
                  sysfs_close_device(clsdev->sysdevice);
      }

      clsdev->sysdevice = sysfs_open_device_path(devlink->target);
      if (clsdev->sysdevice == NULL)
            return NULL;

      return (clsdev->sysdevice);
}
                        
/**
 * sysfs_get_classdev_driver: returns the sysfs_driver corresponding to
 *          sysfs_class_device, if present
 * @clsdev: class device whose sysfs_device is required
 * Returns sysfs_driver on success, NULL on error or if driver is not
 * implemented
 */ 
struct sysfs_driver *sysfs_get_classdev_driver
                  (struct sysfs_class_device *clsdev)
{
      struct sysfs_link *drvlink = NULL;
      char drvpath[SYSFS_PATH_MAX];
      
      if (clsdev == NULL) {
            errno = EINVAL;
            return NULL;
      }
      safestrcpy(drvpath, clsdev->path);
      safestrcat(drvpath, "/driver");
      if ((sysfs_path_is_link(drvpath)) != 0) {
            if (clsdev->driver != NULL) {
                  sysfs_close_driver(clsdev->driver);
                  clsdev->driver = NULL;
            }
            return NULL;
      }
       
      if (clsdev->directory == NULL) {
            clsdev->directory = sysfs_open_directory(clsdev->path);
            if (clsdev->directory == NULL)
                  return NULL;
      }
      drvlink = sysfs_get_directory_link(clsdev->directory, "driver");
      if (drvlink == NULL) {
            if (clsdev->driver != NULL) {
                  dprintf("Driver link no longer exists\n");
                  sysfs_close_driver(clsdev->driver);
                  clsdev->driver = NULL;
            }
            return NULL;
      }
      if (clsdev->driver != NULL) {
            if (!strncmp(drvlink->target, clsdev->driver->path,
                                                SYSFS_PATH_MAX))
                  /* driver hasn't changed */
                  return (clsdev->driver);
            else
                  /* come here only if the device link for has changed */
                  sysfs_close_driver(clsdev->driver);
      }
            
      clsdev->driver = sysfs_open_driver_path(drvlink->target);
      if (clsdev->driver == NULL)
            return NULL;

      return (clsdev->driver);
}

/** 
 * get_blockdev_parent: Get the parent class device for a "block" subsystem 
 *          device if present
 * @clsdev: block subsystem class device whose parent needs to be found
 * Returns 0 on success and 1 on error
 */
static int get_blockdev_parent(struct sysfs_class_device *clsdev)
{
      char parent_path[SYSFS_PATH_MAX], *c = NULL;

      safestrcpy(parent_path, clsdev->path);
      c = strstr(parent_path, SYSFS_BLOCK_NAME);
      if (c == NULL) {
            dprintf("Class device %s does not belong to BLOCK subsystem\n",
                        clsdev->name);
            return 1;
      }
      c += strlen(SYSFS_BLOCK_NAME);
      if (*c == '/')
            c++;
      else
            goto errout;

       /* validate whether the given class device is a partition or not */
        if ((strncmp(c, clsdev->name, strlen(clsdev->name))) == 0) {
                dprintf("%s not a partition\n", clsdev->name);
                return 1;
        }
                  
            c = strchr(c, '/');
      if (c == NULL)
            goto errout;

      *c = '\0';
                              
      clsdev->parent = sysfs_open_class_device_path(parent_path);
      if (clsdev->parent == NULL) {
            dprintf("Error opening the parent class device at %s\n", 
                                                parent_path);
            return 1;
      }
      return 0;

errout:
      dprintf("Invalid path %s\n", clsdev->path);
      return 1;
}

/**
 * sysfs_get_classdev_parent: Retrieves the parent of a class device. 
 *    eg., when working with hda1, this function can be used to retrieve the
 *          sysfs_class_device for hda
 *          
 * @clsdev: class device whose parent details are required.
 * Returns sysfs_class_device of the parent on success, NULL on failure
 */ 
struct sysfs_class_device *sysfs_get_classdev_parent
                        (struct sysfs_class_device *clsdev)
{
      if (clsdev == NULL) {
            errno = EINVAL;
            return NULL;
      }
      if (clsdev->parent != NULL)
            return (clsdev->parent);
      
      /* 
       * As of now, only block devices have a parent child heirarchy in sysfs
       * We do not know, if, in the future, more classes will have a similar
       * structure. Hence, we now call a specialized function for block and
       * later we can add support functions for other subsystems as required.
       */ 
      if (!(strncmp(clsdev->classname, SYSFS_BLOCK_NAME, 
                              sizeof(SYSFS_BLOCK_NAME)))) {
            if ((get_blockdev_parent(clsdev)) == 0) 
                  return (clsdev->parent);
      }
      return NULL;
}

/**
 * get_classdev_path: given the class and a device in the class, return the
 *          absolute path to the device
 * @classname: name of the class
 * @clsdev: the class device
 * @path: buffer to return path
 * @psize: size of "path"
 * Returns 0 on SUCCESS or -1 on error
 */
static int get_classdev_path(const char *classname, const char *clsdev, 
            char *path, size_t len)
{
      if (classname == NULL || clsdev == NULL || path == NULL) {
            errno = EINVAL;
            return -1;
      }
        if (sysfs_get_mnt_path(path, len) != 0) {
                dprintf("Error getting sysfs mount path\n");
                return -1;
      }
      if (strncmp(classname, SYSFS_BLOCK_NAME,
                        sizeof(SYSFS_BLOCK_NAME)) == 0) {
            safestrcatmax(path, "/", len);
            safestrcatmax(path, SYSFS_BLOCK_NAME, len);
      } else {
            safestrcatmax(path, "/", len);
            safestrcatmax(path, SYSFS_CLASS_NAME, len);
            safestrcatmax(path, "/", len);
            safestrcatmax(path, classname, len);
      }
      safestrcatmax(path, "/", len);
      safestrcatmax(path, clsdev, len);
      return 0;
}

/**
 * sysfs_open_class_device: Locates a specific class_device and returns it.
 * Class_device must be closed using sysfs_close_class_device
 * @classname: Class to search
 * @name: name of the class_device
 * 
 * NOTE:
 *    Call sysfs_close_class_device() to close the class device
 */
struct sysfs_class_device *sysfs_open_class_device
            (const char *classname, const char *name)
{
      char devpath[SYSFS_PATH_MAX];
      struct sysfs_class_device *cdev = NULL;

      if (classname == NULL || name == NULL) {
            errno = EINVAL;
            return NULL;
      }
      
      memset(devpath, 0, SYSFS_PATH_MAX);
      if ((get_classdev_path(classname, name, devpath, 
                              SYSFS_PATH_MAX)) != 0) {
            dprintf("Error getting to device %s on class %s\n",
                                          name, classname);
            return NULL;
      }
      
      cdev = sysfs_open_class_device_path(devpath);
      if (cdev == NULL) {
            dprintf("Error getting class device %s from class %s\n",
                        name, classname);
            return NULL;
      }
      return cdev;
}

/**
 * sysfs_get_classdev_attributes: returns a dlist of attributes for
 *    the requested class_device
 * @cdev: sysfs_class_dev for which attributes are needed
 * returns a dlist of attributes if exists, NULL otherwise
 */
struct dlist *sysfs_get_classdev_attributes(struct sysfs_class_device *cdev)
{
      if (cdev == NULL)
            return NULL;

      if (cdev->directory == NULL) {
            cdev->directory = sysfs_open_directory(cdev->path);
            if (cdev->directory == NULL) 
                  return NULL;
      }
      if (cdev->directory->attributes == NULL) {
            if ((sysfs_read_dir_attributes(cdev->directory)) != 0) 
                  return NULL;
      }
      return (cdev->directory->attributes);
}

/**
 * sysfs_refresh_clsassdev_attributes: refreshes the driver's list of attributes
 * @clsdev: sysfs_class_device whose attributes to refresh
 *
 * NOTE: Upon return, prior references to sysfs_attributes for this classdev
 *              _may_ not be valid
 *
 * Returns list of attributes on success and NULL on failure
 */
struct dlist *sysfs_refresh_classdev_attributes
                  (struct sysfs_class_device *clsdev)
{
      if (clsdev == NULL) {
            errno = EINVAL;
            return NULL;
      }

      if (clsdev->directory == NULL)
            return (sysfs_get_classdev_attributes(clsdev));

      if ((sysfs_refresh_dir_attributes(clsdev->directory)) != 0) {
            dprintf("Error refreshing class_device attributes\n");
            return NULL;
      }

      return (clsdev->directory->attributes);
}

/**
 * sysfs_get_classdev_attr: searches class device's attributes by name
 * @clsdev: class device to look through
 * @name: attribute name to get
 * returns sysfs_attribute reference with success or NULL with error
 */
struct sysfs_attribute *sysfs_get_classdev_attr
            (struct sysfs_class_device *clsdev, const char *name)
{
      struct sysfs_attribute *cur = NULL;
      struct sysfs_directory *sdir = NULL;
      struct dlist *attrlist = NULL;
      
      if (clsdev == NULL || name == NULL) {
            errno = EINVAL;
            return NULL;
      }
      
      /* 
       * First, see if it's in the current directory. Then look at 
       * subdirs since class devices can have subdirs of attributes.
       */ 
      attrlist = sysfs_get_classdev_attributes(clsdev);
      if (attrlist != NULL) {
            cur = sysfs_get_directory_attribute(clsdev->directory,
                                    (char *)name);
            if (cur != NULL)
                  return cur;
      }

      if (clsdev->directory->subdirs == NULL) 
            if ((sysfs_read_dir_subdirs(clsdev->directory)) != 0 ||
                clsdev->directory->subdirs == NULL) 
                  return NULL;

      if (clsdev->directory->subdirs != NULL) {
            dlist_for_each_data(clsdev->directory->subdirs, sdir,
                                    struct sysfs_directory) {
                  if ((sysfs_path_is_dir(sdir->path)) != 0) 
                        continue;
                  cur = sysfs_get_directory_attribute(sdir,
                                          (char *)name);
                  if (cur == NULL)
                        continue;
            }
      }
      return cur;
}

/**
 * sysfs_open_classdev_attr: read an attribute for a given class device
 * @classname: name of the class on which to look
 * @dev: class device name for which the attribute has to be read
 * @attrib: attribute to read
 * Returns sysfs_attribute * on SUCCESS and NULL on error
 * 
 * NOTE:
 *    A call to sysfs_close_attribute() is required to close the
 *    attribute returned and to free memory
 */
struct sysfs_attribute *sysfs_open_classdev_attr(const char *classname,
            const char *dev, const char *attrib)
{
      struct sysfs_attribute *attribute = NULL;
      char path[SYSFS_PATH_MAX];

      if (classname == NULL || dev == NULL || attrib == NULL) {
            errno = EINVAL;
            return NULL;
      }
      memset(path, 0, SYSFS_PATH_MAX);
      if ((get_classdev_path(classname, dev, path, SYSFS_PATH_MAX)) != 0) {
            dprintf("Error getting to device %s on class %s\n",
                                    dev, classname);
            return NULL;
      }
      safestrcat(path, "/");
      safestrcat(path, attrib);
      attribute = sysfs_open_attribute(path);
      if (attribute == NULL) {
            dprintf("Error opening attribute %s on class device %s\n",
                        attrib, dev);
            return NULL;
      }
      if ((sysfs_read_attribute(attribute)) != 0) {
            dprintf("Error reading attribute %s for class device %s\n",
                        attrib, dev);
            sysfs_close_attribute(attribute);
            return NULL;
      }
      return attribute;
}


Generated by  Doxygen 1.6.0   Back to index