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709 lines
18 KiB
C
709 lines
18 KiB
C
/*
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* sysfs_class.c
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*
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* Generic class utility functions for libsysfs
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*
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* Copyright (C) IBM Corp. 2003
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*
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*/
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#include "libsysfs.h"
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#include "sysfs.h"
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static void sysfs_close_cls_dev(void *dev)
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{
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sysfs_close_class_device((struct sysfs_class_device *)dev);
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}
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/**
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* class_name_equal: compares class_devices' name
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* @a: class_name looking for
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* @b: sysfs_class_device being compared
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*/
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static int class_name_equal(void *a, void *b)
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{
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if (a == NULL || b == NULL)
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return 0;
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if (strcmp(((char *)a), ((struct sysfs_class_device *)b)->name) == 0)
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return 1;
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return 0;
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}
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/**
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* sysfs_close_class_device: closes a single class device.
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* @dev: class device to close.
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*/
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void sysfs_close_class_device(struct sysfs_class_device *dev)
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{
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if (dev != NULL) {
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if (dev->directory != NULL)
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sysfs_close_directory(dev->directory);
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if (dev->sysdevice != NULL)
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sysfs_close_device(dev->sysdevice);
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if (dev->driver != NULL)
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sysfs_close_driver(dev->driver);
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if (dev->parent != NULL)
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sysfs_close_class_device(dev->parent);
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free(dev);
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}
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}
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/**
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* sysfs_close_class: close single class
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* @cls: class structure
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*/
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void sysfs_close_class(struct sysfs_class *cls)
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{
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if (cls != NULL) {
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if (cls->directory != NULL)
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sysfs_close_directory(cls->directory);
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if (cls->devices != NULL)
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dlist_destroy(cls->devices);
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free(cls);
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}
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}
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/**
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* alloc_class_device: mallocs and initializes new class device struct.
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* returns sysfs_class_device or NULL.
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*/
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static struct sysfs_class_device *alloc_class_device(void)
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{
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return (struct sysfs_class_device *)
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calloc(1, sizeof(struct sysfs_class_device));
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}
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/**
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* alloc_class: mallocs new class structure
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* returns sysfs_class struct or NULL
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*/
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static struct sysfs_class *alloc_class(void)
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{
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return (struct sysfs_class *)calloc(1, sizeof(struct sysfs_class));
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}
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/**
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* set_classdev_classname: Grabs classname from path
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* @cdev: class device to set
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* Returns nothing
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*/
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static void set_classdev_classname(struct sysfs_class_device *cdev)
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{
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char *c = NULL, *e = NULL;
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int count = 0;
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c = strstr(cdev->path, SYSFS_CLASS_NAME);
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if (c == NULL) {
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c = strstr(cdev->path, SYSFS_BLOCK_NAME);
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} else {
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c = strchr(c, '/');
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}
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if (c == NULL)
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safestrcpy(cdev->classname, SYSFS_UNKNOWN);
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else {
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if (*c == '/')
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c++;
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e = c;
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while (e != NULL && *e != '/' && *e != '\0') {
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e++;
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count++;
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}
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strncpy(cdev->classname, c, count);
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}
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}
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/**
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* sysfs_open_class_device_path: Opens and populates class device
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* @path: path to class device.
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* returns struct sysfs_class_device with success and NULL with error.
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*/
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struct sysfs_class_device *sysfs_open_class_device_path(const char *path)
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{
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struct sysfs_class_device *cdev = NULL;
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if (path == NULL) {
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errno = EINVAL;
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return NULL;
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}
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if ((sysfs_path_is_dir(path)) != 0) {
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dprintf("%s is not a valid path to a class device\n", path);
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return NULL;
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}
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cdev = alloc_class_device();
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if (cdev == NULL) {
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dprintf("calloc failed\n");
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return NULL;
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}
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if ((sysfs_get_name_from_path(path, cdev->name, SYSFS_NAME_LEN)) != 0) {
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errno = EINVAL;
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dprintf("Error getting class device name\n");
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sysfs_close_class_device(cdev);
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return NULL;
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}
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safestrcpy(cdev->path, path);
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if ((sysfs_remove_trailing_slash(cdev->path)) != 0) {
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dprintf("Invalid path to class device %s\n", cdev->path);
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sysfs_close_class_device(cdev);
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return NULL;
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}
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set_classdev_classname(cdev);
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return cdev;
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}
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/**
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* sysfs_get_class_devices: gets all devices for class
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* @cls: class to get devices for
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* returns dlist of class_devices with success and NULL with error
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*/
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struct dlist *sysfs_get_class_devices(struct sysfs_class *cls)
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{
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struct sysfs_class_device *dev = NULL;
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struct sysfs_directory *cur = NULL;
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if (cls == NULL) {
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errno = EINVAL;
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return NULL;
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}
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if (cls->devices != NULL)
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return cls->devices;
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if (cls->directory == NULL) {
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cls->directory = sysfs_open_directory(cls->path);
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if (cls->directory == NULL)
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return NULL;
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}
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if ((sysfs_read_dir_subdirs(cls->directory)) != 0)
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return NULL;
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if (cls->directory->subdirs != NULL) {
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dlist_for_each_data(cls->directory->subdirs, cur,
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struct sysfs_directory) {
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dev = sysfs_open_class_device_path(cur->path);
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if (dev == NULL) {
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dprintf("Error opening device at %s\n",
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cur->path);
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continue;
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}
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if (cls->devices == NULL)
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cls->devices = dlist_new_with_delete
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(sizeof(struct sysfs_class_device),
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sysfs_close_cls_dev);
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dlist_unshift_sorted(cls->devices, dev, sort_list);
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}
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}
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return cls->devices;
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}
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/**
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* sysfs_open_class: opens specific class and all its devices on system
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* returns sysfs_class structure with success or NULL with error.
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*/
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struct sysfs_class *sysfs_open_class(const char *name)
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{
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struct sysfs_class *cls = NULL;
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char classpath[SYSFS_PATH_MAX];
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if (name == NULL) {
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errno = EINVAL;
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return NULL;
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}
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memset(classpath, 0, SYSFS_PATH_MAX);
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if ((sysfs_get_mnt_path(classpath, SYSFS_PATH_MAX)) != 0) {
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dprintf("Sysfs not supported on this system\n");
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return NULL;
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}
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/*
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* We shall now treat "block" also as a class. Hence, check here
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* if "name" is "block" and proceed accordingly
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*/
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if (strcmp(name, SYSFS_BLOCK_NAME) == 0) {
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safestrcat(classpath, "/");
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safestrcat(classpath, SYSFS_BLOCK_NAME);
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} else {
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safestrcat(classpath, "/");
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safestrcat(classpath, SYSFS_CLASS_NAME);
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safestrcat(classpath, "/");
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safestrcat(classpath, name);
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}
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if ((sysfs_path_is_dir(classpath)) != 0) {
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dprintf("Class %s not found on the system\n", name);
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return NULL;
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}
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cls = alloc_class();
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if (cls == NULL) {
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dprintf("calloc failed\n");
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return NULL;
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}
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safestrcpy(cls->name, name);
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safestrcpy(cls->path, classpath);
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if ((sysfs_remove_trailing_slash(cls->path)) != 0) {
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dprintf("Invalid path to class device %s\n", cls->path);
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sysfs_close_class(cls);
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return NULL;
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}
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return cls;
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}
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/**
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* sysfs_get_class_device: Get specific class device using the device's id
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* @class: class to find device on
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* @name: class name of the device
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*/
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struct sysfs_class_device *sysfs_get_class_device(struct sysfs_class *cls,
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char *name)
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{
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if (cls == NULL || name == NULL) {
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errno = EINVAL;
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return NULL;
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}
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if (cls->devices == NULL) {
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cls->devices = sysfs_get_class_devices(cls);
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if (cls->devices == NULL)
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return NULL;
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}
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return (struct sysfs_class_device *)dlist_find_custom(cls->devices,
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name, class_name_equal);
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}
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/**
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* sysfs_get_classdev_device: returns the sysfs_device corresponding to
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* sysfs_class_device, if present
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* @clsdev: class device whose sysfs_device is required
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* Returns sysfs_device on success, NULL on error or if device is not
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* implemented
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*/
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struct sysfs_device *sysfs_get_classdev_device
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(struct sysfs_class_device *clsdev)
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{
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struct sysfs_link *devlink = NULL;
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char devpath[SYSFS_PATH_MAX];
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if (clsdev == NULL) {
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errno = EINVAL;
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return NULL;
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}
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safestrcpy(devpath, clsdev->path);
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safestrcat(devpath, "/device");
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if ((sysfs_path_is_link(devpath)) != 0) {
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if (clsdev->sysdevice != NULL) {
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sysfs_close_device(clsdev->sysdevice);
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clsdev->sysdevice = NULL;
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}
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return NULL;
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}
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if (clsdev->directory == NULL) {
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clsdev->directory = sysfs_open_directory(clsdev->path);
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if (clsdev->directory == NULL)
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return NULL;
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}
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devlink = sysfs_get_directory_link(clsdev->directory, "device");
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if (devlink == NULL) {
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if (clsdev->sysdevice != NULL) {
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dprintf("Device link no longer exists\n");
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sysfs_close_device(clsdev->sysdevice);
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clsdev->sysdevice = NULL;
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}
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return NULL;
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}
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if (clsdev->sysdevice != NULL) {
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if (!strncmp(devlink->target, clsdev->sysdevice->path,
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SYSFS_PATH_MAX))
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/* sysdevice hasn't changed */
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return (clsdev->sysdevice);
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else
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/* come here only if the device link for has changed */
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sysfs_close_device(clsdev->sysdevice);
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}
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clsdev->sysdevice = sysfs_open_device_path(devlink->target);
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if (clsdev->sysdevice == NULL)
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return NULL;
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return (clsdev->sysdevice);
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}
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/**
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* sysfs_get_classdev_driver: returns the sysfs_driver corresponding to
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* sysfs_class_device, if present
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* @clsdev: class device whose sysfs_device is required
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* Returns sysfs_driver on success, NULL on error or if driver is not
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* implemented
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*/
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struct sysfs_driver *sysfs_get_classdev_driver
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(struct sysfs_class_device *clsdev)
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{
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struct sysfs_link *drvlink = NULL;
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char drvpath[SYSFS_PATH_MAX];
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if (clsdev == NULL) {
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errno = EINVAL;
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return NULL;
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}
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safestrcpy(drvpath, clsdev->path);
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safestrcat(drvpath, "/driver");
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if ((sysfs_path_is_link(drvpath)) != 0) {
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if (clsdev->driver != NULL) {
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sysfs_close_driver(clsdev->driver);
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clsdev->driver = NULL;
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}
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return NULL;
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}
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if (clsdev->directory == NULL) {
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clsdev->directory = sysfs_open_directory(clsdev->path);
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if (clsdev->directory == NULL)
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return NULL;
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}
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drvlink = sysfs_get_directory_link(clsdev->directory, "driver");
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if (drvlink == NULL) {
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if (clsdev->driver != NULL) {
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dprintf("Driver link no longer exists\n");
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sysfs_close_driver(clsdev->driver);
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clsdev->driver = NULL;
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}
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return NULL;
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}
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if (clsdev->driver != NULL) {
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if (!strncmp(drvlink->target, clsdev->driver->path,
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SYSFS_PATH_MAX))
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/* driver hasn't changed */
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return (clsdev->driver);
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else
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/* come here only if the device link for has changed */
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sysfs_close_driver(clsdev->driver);
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}
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clsdev->driver = sysfs_open_driver_path(drvlink->target);
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if (clsdev->driver == NULL)
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return NULL;
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return (clsdev->driver);
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}
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/**
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* get_blockdev_parent: Get the parent class device for a "block" subsystem
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* device if present
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* @clsdev: block subsystem class device whose parent needs to be found
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* Returns 0 on success and 1 on error
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*/
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static int get_blockdev_parent(struct sysfs_class_device *clsdev)
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{
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char parent_path[SYSFS_PATH_MAX], *c = NULL;
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safestrcpy(parent_path, clsdev->path);
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c = strstr(parent_path, SYSFS_BLOCK_NAME);
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if (c == NULL) {
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dprintf("Class device %s does not belong to BLOCK subsystem\n",
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clsdev->name);
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return 1;
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}
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c += strlen(SYSFS_BLOCK_NAME);
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if (*c == '/')
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c++;
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else
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goto errout;
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/* validate whether the given class device is a partition or not */
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if ((strncmp(c, clsdev->name, strlen(clsdev->name))) == 0) {
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dprintf("%s not a partition\n", clsdev->name);
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return 1;
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}
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c = strchr(c, '/');
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if (c == NULL)
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goto errout;
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*c = '\0';
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clsdev->parent = sysfs_open_class_device_path(parent_path);
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if (clsdev->parent == NULL) {
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dprintf("Error opening the parent class device at %s\n",
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parent_path);
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return 1;
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}
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return 0;
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errout:
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dprintf("Invalid path %s\n", clsdev->path);
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return 1;
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}
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/**
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* sysfs_get_classdev_parent: Retrieves the parent of a class device.
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* eg., when working with hda1, this function can be used to retrieve the
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* sysfs_class_device for hda
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*
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* @clsdev: class device whose parent details are required.
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* Returns sysfs_class_device of the parent on success, NULL on failure
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*/
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struct sysfs_class_device *sysfs_get_classdev_parent
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(struct sysfs_class_device *clsdev)
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{
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if (clsdev == NULL) {
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errno = EINVAL;
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return NULL;
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}
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if (clsdev->parent != NULL)
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return (clsdev->parent);
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/*
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* As of now, only block devices have a parent child heirarchy in sysfs
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* We do not know, if, in the future, more classes will have a similar
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* structure. Hence, we now call a specialized function for block and
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* later we can add support functions for other subsystems as required.
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*/
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if (!(strncmp(clsdev->classname, SYSFS_BLOCK_NAME,
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sizeof(SYSFS_BLOCK_NAME)))) {
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if ((get_blockdev_parent(clsdev)) == 0)
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return (clsdev->parent);
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}
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return NULL;
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}
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/**
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* get_classdev_path: given the class and a device in the class, return the
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* absolute path to the device
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* @classname: name of the class
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* @clsdev: the class device
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* @path: buffer to return path
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* @psize: size of "path"
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* Returns 0 on SUCCESS or -1 on error
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*/
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static int get_classdev_path(const char *classname, const char *clsdev,
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char *path, size_t len)
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{
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if (classname == NULL || clsdev == NULL || path == NULL) {
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errno = EINVAL;
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return -1;
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}
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if (sysfs_get_mnt_path(path, len) != 0) {
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dprintf("Error getting sysfs mount path\n");
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return -1;
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}
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if (strncmp(classname, SYSFS_BLOCK_NAME,
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sizeof(SYSFS_BLOCK_NAME)) == 0) {
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safestrcatmax(path, "/", len);
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safestrcatmax(path, SYSFS_BLOCK_NAME, len);
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} else {
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safestrcatmax(path, "/", len);
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safestrcatmax(path, SYSFS_CLASS_NAME, len);
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safestrcatmax(path, "/", len);
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safestrcatmax(path, classname, len);
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}
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safestrcatmax(path, "/", len);
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safestrcatmax(path, clsdev, len);
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return 0;
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}
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/**
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* sysfs_open_class_device: Locates a specific class_device and returns it.
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* Class_device must be closed using sysfs_close_class_device
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* @classname: Class to search
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* @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 == NULL)
|
|
return NULL;
|
|
|
|
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;
|
|
}
|
|
|