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mirror of https://github.com/systemd/systemd-stable.git synced 2024-10-31 07:51:08 +03:00
systemd-stable/libsysfs/sysfs_class.c

706 lines
18 KiB
C

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