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432 lines
11 KiB
C
432 lines
11 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. 2003-2005
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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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* get_dev_driver: fills in the dev->driver_name field
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* Returns 0 on SUCCESS and -1 on error
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*/
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static int get_dev_driver(struct sysfs_device *dev)
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{
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struct dlist *drvlist;
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char path[SYSFS_PATH_MAX];
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char devpath[SYSFS_PATH_MAX];
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char *drv = NULL, *c;
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if (!dev) {
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errno = EINVAL;
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return -1;
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}
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memset(path, 0, SYSFS_PATH_MAX);
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memset(devpath, 0, SYSFS_PATH_MAX);
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safestrcpymax(path, dev->path, SYSFS_PATH_MAX);
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safestrcatmax(path, "/driver", SYSFS_PATH_MAX);
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if (!sysfs_path_is_link(path)) {
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if (!sysfs_get_link(path, devpath, SYSFS_PATH_MAX)) {
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if (sysfs_get_name_from_path(devpath,
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dev->driver_name, SYSFS_NAME_LEN))
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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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* Devices on on earlier kernels do not have the "driver" link.
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* Look it up in the bus directory.
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*/
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if (dev->bus[0] == '\0')
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return -1;
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memset(path, 0, SYSFS_PATH_MAX);
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memset(devpath, 0, SYSFS_PATH_MAX);
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safestrcpy(path, dev->path);
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c = strstr(path, SYSFS_DEVICES_NAME);
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if (c == NULL) {
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dprintf("Invalid path to device - %s\n", dev->path);
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return -1;
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} else
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*c = '\0';
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safestrcat(path, SYSFS_BUS_NAME);
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safestrcat(path, "/");
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safestrcat(path, dev->bus);
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safestrcat(path, "/");
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safestrcat(path, SYSFS_DRIVERS_NAME);
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drvlist = sysfs_open_directory_list(path);
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if (drvlist) {
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dlist_for_each_data(drvlist, drv, char) {
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safestrcpy(devpath, path);
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safestrcat(devpath, "/");
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safestrcat(devpath, drv);
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safestrcat(devpath, "/");
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safestrcat(devpath, dev->bus_id);
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if (sysfs_path_is_link(devpath) == 0) {
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safestrcpy(dev->driver_name, drv);
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sysfs_close_list(drvlist);
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return 0;
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}
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}
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sysfs_close_list(drvlist);
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}
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return -1;
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}
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/**
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* sysfs_get_device_bus: retrieves the bus name the device is on, checks path
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* to bus' link to make sure it has correct device.
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* @dev: device to get busname.
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* returns 0 with success and -1 with error.
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*/
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int sysfs_get_device_bus(struct sysfs_device *dev)
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{
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char devpath[SYSFS_PATH_MAX];
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char subsys[SYSFS_NAME_LEN];
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char path[SYSFS_PATH_MAX];
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char target[SYSFS_PATH_MAX];
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char *bus = NULL, *c;
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struct dlist *buslist;
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if (!dev) {
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errno = EINVAL;
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return -1;
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}
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memset(path, 0, SYSFS_PATH_MAX);
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memset(devpath, 0, SYSFS_PATH_MAX);
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safestrcpymax(path, dev->path, SYSFS_PATH_MAX);
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safestrcatmax(path, "/bus", SYSFS_PATH_MAX);
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if (!sysfs_path_is_link(path)) {
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if (!sysfs_get_link(path, devpath, SYSFS_PATH_MAX)) {
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if (sysfs_get_name_from_path(devpath,
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dev->bus, SYSFS_NAME_LEN))
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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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* Devices on on earlier kernels do not have the "bus" link.
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* Look it up in the bus directory.
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*/
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memset(subsys, 0, SYSFS_NAME_LEN);
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safestrcpy(subsys, dev->path);
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c = strstr(subsys, SYSFS_DEVICES_NAME);
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if (c == NULL) {
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dprintf("Invalid path to device - %s\n", dev->path);
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return -1;
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} else
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*c = '\0';
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safestrcat(subsys, SYSFS_BUS_NAME);
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buslist = sysfs_open_directory_list(subsys);
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if (buslist) {
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dlist_for_each_data(buslist, bus, char) {
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memset(path, 0, SYSFS_PATH_MAX);
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safestrcpy(path, subsys);
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safestrcat(path, "/");
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safestrcat(path, bus);
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safestrcat(path, "/");
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safestrcat(path, SYSFS_DEVICES_NAME);
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safestrcat(path, "/");
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safestrcat(path, dev->bus_id);
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if ((sysfs_path_is_link(path)) == 0) {
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memset(target, 0, SYSFS_PATH_MAX);
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if (sysfs_get_link(path, target,
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SYSFS_PATH_MAX)) {
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dprintf("Error getting link target\n");
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sysfs_close_list(buslist);
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return -1;
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}
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if (!(strncmp(target, dev->path,
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SYSFS_PATH_MAX))) {
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safestrcpy(dev->bus, bus);
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sysfs_close_list(buslist);
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return 0;
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}
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}
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}
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sysfs_close_list(buslist);
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}
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return -1;
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}
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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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void sysfs_close_device_tree(struct sysfs_device *devroot)
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{
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if (devroot) {
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if (devroot->children) {
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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_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) {
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if (dev->parent)
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sysfs_close_device(dev->parent);
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if (dev->children && dev->children->count)
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dlist_destroy(dev->children);
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if (dev->attrlist)
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dlist_destroy(dev->attrlist);
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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_open_device_path: 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_path(const char *path)
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{
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struct sysfs_device *dev;
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if (!path) {
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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)) {
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dprintf("Incorrect path to device: %s\n", path);
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return NULL;
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}
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dev = alloc_device();
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if (!dev) {
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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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if (sysfs_get_name_from_path(path, dev->bus_id, SYSFS_NAME_LEN)) {
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errno = EINVAL;
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dprintf("Error getting device bus_id\n");
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sysfs_close_device(dev);
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return NULL;
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}
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safestrcpy(dev->path, path);
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if (sysfs_remove_trailing_slash(dev->path)) {
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dprintf("Invalid path to device %s\n", dev->path);
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sysfs_close_device(dev);
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return NULL;
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}
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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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safestrcpy(dev->name, dev->bus_id);
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if (sysfs_get_device_bus(dev))
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dprintf("Could not get device bus\n");
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if (get_dev_driver(dev)) {
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dprintf("Could not get device %s's driver\n", dev->bus_id);
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safestrcpy(dev->driver_name, SYSFS_UNKNOWN);
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}
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return dev;
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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 char *name)
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{
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if (!dev || !name) {
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errno = EINVAL;
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return NULL;
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}
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return get_attribute(dev, (char *)name);
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}
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/**
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* sysfs_get_device_attributes: gets list of device attributes
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* @dev: device whose attributes list is needed
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* returns dlist of attributes on success or NULL on error
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*/
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struct dlist *sysfs_get_device_attributes(struct sysfs_device *dev)
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{
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if (!dev) {
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errno = EINVAL;
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return NULL;
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}
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return get_attributes_list(dev);
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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 char *device, const char *bus,
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char *path, size_t psize)
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{
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char bus_path[SYSFS_PATH_MAX];
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if (!device || !path) {
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errno = EINVAL;
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return -1;
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}
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memset(bus_path, 0, SYSFS_PATH_MAX);
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if (sysfs_get_mnt_path(bus_path, SYSFS_PATH_MAX)) {
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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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safestrcat(bus_path, "/");
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safestrcat(bus_path, SYSFS_BUS_NAME);
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safestrcat(bus_path, "/");
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safestrcat(bus_path, bus);
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safestrcat(bus_path, "/");
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safestrcat(bus_path, SYSFS_DEVICES_NAME);
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safestrcat(bus_path, "/");
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safestrcat(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, psize)) {
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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_open_device: open a device by id (use the "bus" subsystem)
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* @bus: bus the device belongs to
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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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* 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(const char *bus, const char *bus_id)
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{
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char sysfs_path[SYSFS_PATH_MAX];
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struct sysfs_device *device;
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if (!bus_id || !bus) {
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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 (get_device_absolute_path(bus_id, bus, sysfs_path,
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SYSFS_PATH_MAX)) {
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dprintf("Error getting to device %s\n", bus_id);
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return NULL;
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}
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device = sysfs_open_device_path(sysfs_path);
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if (!device) {
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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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* sysfs_get_device_parent: opens up given device's parent and returns a
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* reference to its sysfs_device
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* @dev: sysfs_device whose parent is requested
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* Returns sysfs_device of the parent on success and NULL on failure
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*/
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struct sysfs_device *sysfs_get_device_parent(struct sysfs_device *dev)
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{
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char ppath[SYSFS_PATH_MAX], *tmp;
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if (!dev) {
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errno = EINVAL;
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return NULL;
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}
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if (dev->parent)
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return (dev->parent);
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memset(ppath, 0, SYSFS_PATH_MAX);
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safestrcpy(ppath, dev->path);
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tmp = strrchr(ppath, '/');
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if (!tmp) {
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dprintf("Invalid path to device %s\n", ppath);
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return NULL;
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}
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if (*(tmp + 1) == '\0') {
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*tmp = '\0';
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tmp = strrchr(tmp, '/');
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if (tmp == NULL) {
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dprintf("Invalid path to device %s\n", ppath);
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return NULL;
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}
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}
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*tmp = '\0';
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/*
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* All "devices" have the "detach_state" attribute - validate here
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*/
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safestrcat(ppath, "/detach_state");
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if (sysfs_path_is_file(ppath)) {
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dprintf("Device at %s does not have a parent\n", dev->path);
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return NULL;
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}
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tmp = strrchr(ppath, '/');
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*tmp = '\0';
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dev->parent = sysfs_open_device_path(ppath);
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if (!dev->parent) {
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dprintf("Error opening device %s's parent at %s\n",
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dev->bus_id, ppath);
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return NULL;
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}
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return (dev->parent);
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}
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