539 lines
14 KiB
C
539 lines
14 KiB
C
/*
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* sysfs_device.c
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*
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* Generic device 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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/**
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* sysfs_close_device_tree: closes every device in the supplied tree,
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* closing children only.
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* @devroot: device root of tree.
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*/
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static void sysfs_close_device_tree(struct sysfs_device *devroot)
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{
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if (devroot != NULL) {
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if (devroot->children != NULL) {
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struct sysfs_device *child = NULL;
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dlist_for_each_data(devroot->children, child,
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struct sysfs_device) {
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sysfs_close_device_tree(child);
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}
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}
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sysfs_close_device(devroot);
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}
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}
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/**
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* sysfs_del_device: routine for dlist integration
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*/
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static void sysfs_del_device(void *dev)
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{
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sysfs_close_device((struct sysfs_device *)dev);
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}
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/**
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* sysfs_close_dev_tree: routine for dlist integration
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*/
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static void sysfs_close_dev_tree(void *dev)
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{
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sysfs_close_device_tree((struct sysfs_device *)dev);
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}
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/**
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* sysfs_close_device: closes and cleans up a device
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* @dev = device to clean up
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*/
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void sysfs_close_device(struct sysfs_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->children != NULL && dev->children->count == 0)
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dlist_destroy(dev->children);
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free(dev);
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}
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}
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/**
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* alloc_device: allocates and initializes device structure
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* returns struct sysfs_device
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*/
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static struct sysfs_device *alloc_device(void)
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{
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return (struct sysfs_device *)calloc(1, sizeof(struct sysfs_device));
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}
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/**
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* sysfs_get_device_attr: searches dev's attributes by name
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* @dev: device to look through
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* @name: attribute name to get
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* returns sysfs_attribute reference with success or NULL with error.
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*/
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struct sysfs_attribute *sysfs_get_device_attr(struct sysfs_device *dev,
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const unsigned char *name)
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{
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struct sysfs_attribute *cur = NULL;
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if (dev == NULL || dev->directory == NULL
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|| dev->directory->attributes == NULL || name == NULL) {
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errno = EINVAL;
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return NULL;
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}
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cur = sysfs_get_directory_attribute(dev->directory,
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(unsigned char *)name);
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if (cur != NULL)
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return cur;
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return NULL;
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}
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/**
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* sysfs_open_device: opens and populates device structure
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* @path: path to device, this is the /sys/devices/ path
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* returns sysfs_device structure with success or NULL with error
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*/
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struct sysfs_device *sysfs_open_device(const unsigned char *path)
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{
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struct sysfs_device *dev = NULL;
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struct sysfs_directory *sdir = 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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dev = alloc_device();
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if (dev == NULL) {
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dprintf("Error allocating device at %s\n", path);
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return NULL;
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}
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sdir = sysfs_open_directory(path);
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if (sdir == NULL) {
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dprintf("Invalid device at %s\n", path);
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errno = EINVAL;
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sysfs_close_device(dev);
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return NULL;
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}
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if ((sysfs_read_directory(sdir)) != 0) {
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dprintf("Error reading device directory at %s\n", path);
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sysfs_close_directory(sdir);
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sysfs_close_device(dev);
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return NULL;
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}
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dev->directory = sdir;
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strcpy(dev->bus_id, sdir->name);
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strcpy(dev->path, sdir->path);
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/*
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* The "name" attribute no longer exists... return the device's
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* sysfs representation instead, in the "dev->name" field, which
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* implies that the dev->name and dev->bus_id contain same data.
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*/
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strncpy(dev->name, sdir->name, SYSFS_NAME_LEN);
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return dev;
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}
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/**
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* sysfs_open_device_tree: opens root device and all of its children,
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* creating a tree of devices. Only opens children.
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* @path: sysfs path to devices
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* returns struct sysfs_device and its children with success or NULL with
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* error.
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*/
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static struct sysfs_device *sysfs_open_device_tree(const unsigned char *path)
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{
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struct sysfs_device *rootdev = NULL, *new = NULL;
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struct sysfs_directory *cur = 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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rootdev = sysfs_open_device(path);
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if (rootdev == NULL) {
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dprintf("Error opening root device at %s\n", path);
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return NULL;
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}
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if (rootdev->directory->subdirs != NULL) {
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dlist_for_each_data(rootdev->directory->subdirs, cur,
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struct sysfs_directory) {
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new = sysfs_open_device_tree(cur->path);
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if (new == NULL) {
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dprintf("Error opening device tree at %s\n",
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cur->path);
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sysfs_close_device_tree(rootdev);
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return NULL;
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}
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if (rootdev->children == NULL)
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rootdev->children = dlist_new_with_delete
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(sizeof(struct sysfs_device),
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sysfs_del_device);
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dlist_unshift(rootdev->children, new);
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}
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}
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return rootdev;
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}
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/**
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* sysfs_close_root_device: closes root and all devices
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* @root: root device to close
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*/
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void sysfs_close_root_device(struct sysfs_root_device *root)
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{
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if (root != NULL) {
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if (root->devices != NULL)
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dlist_destroy(root->devices);
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if (root->directory != NULL)
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sysfs_close_directory(root->directory);
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free(root);
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}
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}
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/**
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* open_root_device_dir: opens up sysfs_directory for specific root dev
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* @name: name of root
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* returns struct sysfs_directory with success and NULL with error
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*/
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static struct sysfs_directory *open_root_device_dir(const unsigned char *name)
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{
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struct sysfs_directory *rdir = NULL;
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unsigned char rootpath[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(rootpath, 0, SYSFS_PATH_MAX);
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if (sysfs_get_mnt_path(rootpath, 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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strcat(rootpath, SYSFS_DEVICES_DIR);
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strcat(rootpath, "/");
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strcat(rootpath, name);
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rdir = sysfs_open_directory(rootpath);
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if (rdir == NULL) {
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errno = EINVAL;
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dprintf ("Root device %s not supported on this system\n",
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name);
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return NULL;
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}
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if (sysfs_read_directory(rdir) != 0) {
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dprintf ("Error reading %s root device at dir %s\n", name,
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rootpath);
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sysfs_close_directory(rdir);
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return NULL;
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}
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return rdir;
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}
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/**
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* get_all_root_devices: opens up all the devices under this root device
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* @root: root device to open devices for
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* returns 0 with success and -1 with error
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*/
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static int get_all_root_devices(struct sysfs_root_device *root)
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{
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struct sysfs_device *dev = NULL;
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struct sysfs_directory *cur = NULL;
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if (root == NULL || root->directory == NULL) {
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errno = EINVAL;
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return -1;
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}
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if (root->directory->subdirs == NULL)
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return 0;
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dlist_for_each_data(root->directory->subdirs, cur,
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struct sysfs_directory) {
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dev = sysfs_open_device_tree(cur->path);
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if (dev == NULL) {
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dprintf ("Error opening device at %s\n", cur->path);
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continue;
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}
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if (root->devices == NULL)
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root->devices = dlist_new_with_delete
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(sizeof(struct sysfs_device),
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sysfs_close_dev_tree);
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dlist_unshift(root->devices, dev);
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}
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return 0;
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}
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/**
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* sysfs_open_root_device: opens sysfs devices root and all of its
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* devices.
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* @name: name of /sys/devices/root to open
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* returns struct sysfs_root_device if success and NULL with error
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*/
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struct sysfs_root_device *sysfs_open_root_device(const unsigned char *name)
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{
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struct sysfs_root_device *root = NULL;
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struct sysfs_directory *rootdir = NULL;
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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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root = (struct sysfs_root_device *)calloc
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(1, sizeof(struct sysfs_root_device));
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if (root == NULL) {
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dprintf("calloc failure\n");
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return NULL;
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}
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rootdir = open_root_device_dir(name);
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if (rootdir == NULL) {
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dprintf ("Invalid root device, %s not supported\n", name);
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sysfs_close_root_device(root);
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return NULL;
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}
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strcpy(root->path, rootdir->path);
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root->directory = rootdir;
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if (get_all_root_devices(root) != 0) {
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dprintf ("Error retrieving devices for root %s\n", name);
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sysfs_close_root_device(root);
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return NULL;
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}
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return root;
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}
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/**
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* sysfs_get_device_attributes: returns a dlist of attributes corresponding to
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* the specific device
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* @device: struct sysfs_device * for which attributes are to be returned
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*/
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struct dlist *sysfs_get_device_attributes(struct sysfs_device *device)
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{
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if (device == NULL || device->directory == NULL)
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return NULL;
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return (device->directory->attributes);
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}
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/**
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* sysfs_open_device_by_id: open a device by id (use the "bus" subsystem)
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* @bus_id: bus_id of the device to open - has to be the "bus_id" in
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* /sys/bus/xxx/devices
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* @bus: bus the device belongs to
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* @bsize: size of the bus buffer
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* returns struct sysfs_device if found, NULL otherwise
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* NOTE:
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* 1. Use sysfs_close_device to close the device
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* 2. Bus the device is on must be supplied
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* Use sysfs_find_device_bus to get the bus name
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*/
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struct sysfs_device *sysfs_open_device_by_id(const unsigned char *bus_id,
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const unsigned char *bus, size_t bsize)
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{
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char sysfs_path[SYSFS_PATH_MAX], device_path[SYSFS_PATH_MAX];
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struct sysfs_device *device = NULL;
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if (bus_id == NULL || bus == NULL) {
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errno = EINVAL;
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return NULL;
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}
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memset(sysfs_path, 0, SYSFS_PATH_MAX);
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if ((sysfs_get_mnt_path(sysfs_path, SYSFS_PATH_MAX)) != 0) {
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dprintf("Error getting sysfs mount path\n");
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return NULL;
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}
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strcat(sysfs_path, SYSFS_BUS_DIR);
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strcat(sysfs_path, "/");
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strncat(sysfs_path, bus, bsize);
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strcat(sysfs_path, SYSFS_DEVICES_DIR);
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strcat(sysfs_path, "/");
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strcat(sysfs_path, bus_id);
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/* devices under /sys/bus/xxx/devices are links to devices subsystem */
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if ((sysfs_get_link(sysfs_path, device_path, SYSFS_PATH_MAX)) < 0) {
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dprintf("Error getting device path\n");
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return NULL;
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}
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device = sysfs_open_device(device_path);
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if (device == NULL) {
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dprintf("Error opening device %s\n", bus_id);
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return NULL;
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}
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return device;
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}
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/**
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* get_device_absolute_path: looks up the bus the device is on, gets
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* absolute path to the device
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* @device: device for which path is needed
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* @path: buffer to store absolute path
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* @psize: size of "path"
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* Returns 0 on success -1 on failure
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*/
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static int get_device_absolute_path(const unsigned char *device,
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unsigned char *path, size_t psize)
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{
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unsigned char bus_name[SYSFS_NAME_LEN], bus_path[SYSFS_PATH_MAX];
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if (device == NULL || path == NULL) {
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errno = EINVAL;
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return -1;
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}
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memset(bus_name, 0, SYSFS_NAME_LEN);
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memset(bus_path, 0, SYSFS_NAME_LEN);
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if ((sysfs_find_device_bus(device, bus_name, SYSFS_NAME_LEN)) != 0) {
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dprintf("Device %s not found\n", device);
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return -1;
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}
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if (sysfs_get_mnt_path(bus_path, SYSFS_PATH_MAX) != 0) {
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dprintf ("Sysfs not supported on this system\n");
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return -1;
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}
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strcat(bus_path, SYSFS_BUS_DIR);
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strcat(bus_path, "/");
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strcat(bus_path, bus_name);
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strcat(bus_path, SYSFS_DEVICES_DIR);
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strcat(bus_path, "/");
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strcat(bus_path, device);
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/*
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* We now are at /sys/bus/"bus_name"/devices/"device" which is a link.
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* Now read this link to reach to the device.
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*/
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if ((sysfs_get_link(bus_path, path, SYSFS_PATH_MAX)) != 0) {
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dprintf("Error getting to device %s\n", device);
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return -1;
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}
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return 0;
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}
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/**
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* sysfs_write_device_attr: modify a "writable" attribute for the given device
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* @dev: device bus_id for which attribute has to be changed
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* @attrib: attribute to change
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* @value: value to change to
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* @len: "value" length to write
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* Returns 0 on success -1 on error
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*/
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int sysfs_write_device_attr(unsigned char *dev, unsigned char *attrib,
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unsigned char *value, size_t len)
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{
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struct sysfs_attribute *attribute = NULL;
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unsigned char devpath[SYSFS_PATH_MAX];
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if (dev == NULL || attrib == NULL || value == NULL) {
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errno = EINVAL;
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return -1;
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}
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memset(devpath, 0, SYSFS_PATH_MAX);
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if ((get_device_absolute_path(dev, devpath, SYSFS_PATH_MAX)) != 0) {
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dprintf("Error finding absolute path to device %s\n", dev);
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return -1;
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}
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strcat(devpath, "/");
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strcat(devpath, attrib);
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attribute = sysfs_open_attribute(devpath);
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if (attribute == NULL) {
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dprintf("Attribute %s could not be retrieved for device %s\n",
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attrib, dev);
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return -1;
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}
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if (attribute->method & SYSFS_METHOD_SHOW) {
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if ((sysfs_read_attribute(attribute)) != 0) {
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dprintf("Error reading attribute %s for device %s\n",
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attrib, dev);
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sysfs_close_attribute(attribute);
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return -1;
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}
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}
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if ((sysfs_write_attribute(attribute, value, len)) < 0) {
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dprintf("Error setting %s to %s\n", attrib, value);
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sysfs_close_attribute(attribute);
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return -1;
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}
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sysfs_close_attribute(attribute);
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return 0;
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}
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/**
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* sysfs_read_device_attr: read an attribute of the given device
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* @dev: device bus_id for which attribute has to be changed
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* @attrib: attribute to read
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* @value: buffer to return value in
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* @len: size of buffer available
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* Returns 0 on success -1 on error
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*/
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int sysfs_read_device_attr(unsigned char *dev, unsigned char *attrib,
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unsigned char *value, size_t len)
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{
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struct sysfs_attribute *attribute = NULL;
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unsigned char devpath[SYSFS_PATH_MAX];
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if (dev == NULL || attrib == NULL || value == NULL) {
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errno = EINVAL;
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return -1;
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}
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memset(devpath, 0, SYSFS_PATH_MAX);
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if ((get_device_absolute_path(dev, devpath, SYSFS_PATH_MAX)) != 0) {
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dprintf("Error finding absolute path to device %s\n", dev);
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return -1;
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}
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strcat(devpath, "/");
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strcat(devpath, attrib);
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attribute = sysfs_open_attribute(devpath);
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if (attribute == NULL) {
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dprintf("Error opening attribute %s for device %s\n",
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attrib, dev);
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return -1;
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}
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if (!(attribute->method & SYSFS_METHOD_SHOW)) {
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dprintf("Show method not supported for attribute %s\n",
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attrib);
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sysfs_close_attribute(attribute);
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return -1;
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}
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if ((sysfs_read_attribute(attribute)) != 0) {
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dprintf("Error reading attribute %s for device %s\n",
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attrib, dev);
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sysfs_close_attribute(attribute);
|
|
return -1;
|
|
}
|
|
if (attribute->len > len) {
|
|
dprintf("Value length %d is larger than supplied buffer %d\n",
|
|
attribute->len, len);
|
|
sysfs_close_attribute(attribute);
|
|
return -1;
|
|
}
|
|
strncpy(value, attribute->value, attribute->len);
|
|
value[(attribute->len)+1] = 0;
|
|
sysfs_close_attribute(attribute);
|
|
return 0;
|
|
}
|