705 lines
18 KiB
C
705 lines
18 KiB
C
/*
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* syfs_dir.c
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*
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* Directory 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_del_attribute: routine for dlist integration
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*/
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static void sysfs_del_attribute(void *attr)
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{
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sysfs_close_attribute((struct sysfs_attribute *)attr);
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}
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/**
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* sysfs_del_link: routine for dlist integration
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*/
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static void sysfs_del_link(void *ln)
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{
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sysfs_close_link((struct sysfs_link *)ln);
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}
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/**
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* sysfs_del_dir: routine for dlist integration
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*/
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static void sysfs_del_directory(void *dir)
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{
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sysfs_close_directory((struct sysfs_directory *)dir);
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}
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/**
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* dir_attribute_name_equal: compares dir attributes by name
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* @a: attribute name for comparison
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* @b: sysfs_attribute to be compared.
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* returns 1 if a==b->name or 0 if not equal
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*/
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static int dir_attribute_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(((unsigned char *)a), ((struct sysfs_attribute *)b)->name)
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== 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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* dir_link_name_equal: compares dir links by name
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* @a: link name for comparison
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* @b: sysfs_link to be compared.
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* returns 1 if a==b->name or 0 if not equal
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*/
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static int dir_link_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(((unsigned char *)a), ((struct sysfs_link *)b)->name)
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== 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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* dir_subdir_name_equal: compares subdirs by name
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* @a: name of subdirectory to compare
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* @b: sysfs_directory subdirectory to be compared
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* returns 1 if a==b->name or 0 if not equal
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*/
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static int dir_subdir_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(((unsigned char *)a), ((struct sysfs_directory *)b)->name)
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== 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_attribute: closes and cleans up attribute
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* @sysattr: attribute to close.
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*/
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void sysfs_close_attribute(struct sysfs_attribute *sysattr)
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{
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if (sysattr != NULL) {
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if (sysattr->value != NULL)
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free(sysattr->value);
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free(sysattr);
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}
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}
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/**
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* alloc_attribute: allocates and initializes attribute structure
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* returns struct sysfs_attribute with success and NULL with error.
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*/
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static struct sysfs_attribute *alloc_attribute(void)
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{
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return (struct sysfs_attribute *)
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calloc(1, sizeof(struct sysfs_attribute));
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}
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/**
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* sysfs_open_attribute: creates sysfs_attribute structure
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* @path: path to attribute.
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* returns sysfs_attribute struct with success and NULL with error.
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*/
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struct sysfs_attribute *sysfs_open_attribute(const unsigned char *path)
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{
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struct sysfs_attribute *sysattr = NULL;
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struct stat fileinfo;
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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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sysattr = alloc_attribute();
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if (sysattr == NULL) {
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dprintf("Error allocating attribute 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, sysattr->name, SYSFS_NAME_LEN)
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!= 0) {
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dprintf("Error retrieving attribute name from path: %s\n",
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path);
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sysfs_close_attribute(sysattr);
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return NULL;
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}
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strncpy(sysattr->path, path, sizeof(sysattr->path));
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if ((stat(sysattr->path, &fileinfo)) != 0) {
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dprintf("Stat failed: No such attribute?\n");
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sysattr->method = 0;
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free(sysattr);
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sysattr = NULL;
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} else {
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if (fileinfo.st_mode & S_IRUSR)
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sysattr->method |= SYSFS_METHOD_SHOW;
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if (fileinfo.st_mode & S_IWUSR)
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sysattr->method |= SYSFS_METHOD_STORE;
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}
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return sysattr;
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}
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/**
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* sysfs_write_attribute: write value to the attribute
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* @sysattr: attribute to write
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* @new_value: value to write
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* @len: length of "new_value"
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* returns 0 with success and -1 with error.
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*/
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int sysfs_write_attribute(struct sysfs_attribute *sysattr,
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const unsigned char *new_value, size_t len)
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{
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int fd;
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int length;
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if (sysattr == NULL || new_value == NULL || len == 0) {
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errno = EINVAL;
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return -1;
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}
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if (!(sysattr->method & SYSFS_METHOD_STORE)) {
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dprintf ("Store method not supported for attribute %s\n",
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sysattr->path);
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return -1;
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}
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if (sysattr->method & SYSFS_METHOD_SHOW) {
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if ((strncmp(sysattr->value, new_value, sysattr->len)) == 0) {
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dprintf("Attribute %s already has the requested value %s\n",
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sysattr->name, new_value);
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return 0;
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}
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}
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/*
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* open O_WRONLY since some attributes have no "read" but only
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* "write" permission
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*/
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if ((fd = open(sysattr->path, O_WRONLY)) < 0) {
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dprintf("Error reading attribute %s\n", sysattr->path);
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return -1;
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}
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length = write(fd, new_value, len);
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if (length < 0) {
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dprintf("Error writing to the attribute %s - invalid value?\n",
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sysattr->name);
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close(fd);
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return -1;
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} else if (length != len) {
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dprintf("Could not write %d bytes to attribute %s\n",
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len, sysattr->name);
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/*
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* since we could not write user supplied number of bytes,
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* restore the old value if one available
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*/
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if (sysattr->method & SYSFS_METHOD_SHOW) {
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length = write(fd, sysattr->value, sysattr->len);
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close(fd);
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return -1;
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}
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}
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/*
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* Validate length that has been copied. Alloc appropriate area
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* in sysfs_attribute. Verify first if the attribute supports reading
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* (show method). If it does not, do not bother
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*/
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if (sysattr->method & SYSFS_METHOD_SHOW) {
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if (length != sysattr->len) {
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sysattr->value = (char *)realloc(sysattr->value,
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length);
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sysattr->len = length;
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strncpy(sysattr->value, new_value, length);
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} else {
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/*"length" of the new value is same as old one */
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strncpy(sysattr->value, new_value, length);
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}
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}
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close(fd);
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return 0;
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}
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/**
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* sysfs_read_attribute: reads value from attribute
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* @sysattr: attribute to read
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* returns 0 with success and -1 with error.
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*/
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int sysfs_read_attribute(struct sysfs_attribute *sysattr)
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{
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unsigned char *fbuf = NULL;
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unsigned char *vbuf = NULL;
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size_t length = 0;
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int pgsize = 0;
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int fd;
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if (sysattr == NULL) {
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errno = EINVAL;
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return -1;
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}
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if (!(sysattr->method & SYSFS_METHOD_SHOW)) {
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dprintf("Show method not supported for attribute %s\n",
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sysattr->path);
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return -1;
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}
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pgsize = getpagesize();
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fbuf = (unsigned char *)calloc(1, pgsize+1);
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if (fbuf == NULL) {
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dprintf("calloc failed\n");
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return -1;
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}
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if ((fd = open(sysattr->path, O_RDONLY)) < 0) {
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dprintf("Error reading attribute %s\n", sysattr->path);
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free(fbuf);
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return -1;
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}
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length = read(fd, fbuf, pgsize);
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if (length < 0) {
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dprintf("Error reading from attribute %s\n", sysattr->path);
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close(fd);
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free(fbuf);
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return -1;
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}
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sysattr->len = length;
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close(fd);
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vbuf = (unsigned char *)realloc(fbuf, length+1);
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if (vbuf == NULL) {
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dprintf("realloc failed\n");
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free(fbuf);
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return -1;
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}
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sysattr->value = vbuf;
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return 0;
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}
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/**
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* sysfs_read_attribute_value: given path to attribute, return its value.
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* values can be up to a pagesize, if buffer is smaller the value will
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* be truncated.
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* @attrpath: sysfs path to attribute
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* @value: buffer to put value
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* @vsize: size of value buffer
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* returns 0 with success and -1 with error.
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*/
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int sysfs_read_attribute_value(const unsigned char *attrpath,
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unsigned char *value, size_t vsize)
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{
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struct sysfs_attribute *attr = NULL;
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size_t length = 0;
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if (attrpath == NULL || value == NULL) {
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errno = EINVAL;
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return -1;
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}
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attr = sysfs_open_attribute(attrpath);
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if (attr == NULL) {
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dprintf("Invalid attribute path %s\n", attrpath);
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errno = EINVAL;
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return -1;
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}
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if((sysfs_read_attribute(attr)) != 0 || attr->value == NULL) {
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dprintf("Error reading from attribute %s\n", attrpath);
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sysfs_close_attribute(attr);
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return -1;
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}
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length = strlen(attr->value);
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if (length > vsize)
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dprintf("Value length %d is larger than supplied buffer %d\n",
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length, vsize);
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strncpy(value, attr->value, vsize);
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sysfs_close_attribute(attr);
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return 0;
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}
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/**
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* sysfs_get_value_from_attrbutes: given a linked list of attributes and an
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* attribute name, return its value
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* @attr: attribute to search
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* @name: name to look for
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* returns unsigned char * value - could be NULL
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*/
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unsigned char *sysfs_get_value_from_attributes(struct dlist *attr,
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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 (attr == NULL || name == NULL) {
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errno = EINVAL;
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return NULL;
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}
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dlist_for_each_data(attr, cur, struct sysfs_attribute) {
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if (strcmp(cur->name, name) == 0)
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return cur->value;
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}
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return NULL;
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}
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/**
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* sysfs_close_link: closes and cleans up link.
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* @ln: link to close.
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*/
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void sysfs_close_link(struct sysfs_link *ln)
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{
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if (ln != NULL)
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free(ln);
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}
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/**
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* sysfs_close_directory: closes directory, cleans up attributes and links
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* @sysdir: sysfs_directory to close
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*/
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void sysfs_close_directory(struct sysfs_directory *sysdir)
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{
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if (sysdir != NULL) {
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if (sysdir->subdirs != NULL)
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dlist_destroy(sysdir->subdirs);
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if (sysdir->links != NULL)
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dlist_destroy(sysdir->links);
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if (sysdir->attributes != NULL)
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dlist_destroy(sysdir->attributes);
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free(sysdir);
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}
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}
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/**
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* alloc_directory: allocates and initializes directory structure
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* returns struct sysfs_directory with success or NULL with error.
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*/
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static struct sysfs_directory *alloc_directory(void)
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{
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return (struct sysfs_directory *)
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calloc(1, sizeof(struct sysfs_directory));
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}
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/**
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* alloc_link: allocates and initializes link structure
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* returns struct sysfs_link with success or NULL with error.
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*/
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static struct sysfs_link *alloc_link(void)
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{
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return (struct sysfs_link *)calloc(1, sizeof(struct sysfs_link));
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}
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/**
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* sysfs_read_all_subdirs: calls sysfs_read_directory for all subdirs
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* @sysdir: directory whose subdirs need reading.
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* returns 0 with success and -1 with error.
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*/
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int sysfs_read_all_subdirs(struct sysfs_directory *sysdir)
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{
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struct sysfs_directory *cursub = NULL;
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if (sysdir == NULL) {
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errno = EINVAL;
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return -1;
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}
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if (sysdir->subdirs == NULL)
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return 0;
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dlist_for_each_data(sysdir->subdirs, cursub, struct sysfs_directory) {
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if (sysfs_read_directory(cursub) != 0)
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dprintf ("Error reading subdirectory %s\n",
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cursub->name);
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}
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return 0;
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}
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/**
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* sysfs_open_directory: opens a sysfs directory, creates dir struct, and
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* returns.
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* @path: path of directory to open.
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* returns: struct sysfs_directory * with success and NULL on error.
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*/
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struct sysfs_directory *sysfs_open_directory(const unsigned char *path)
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{
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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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sdir = alloc_directory();
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if (sdir == NULL) {
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dprintf("Error allocating directory %s\n", path);
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return NULL;
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}
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if (sysfs_get_name_from_path(path, sdir->name, SYSFS_NAME_LEN) != 0) {
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dprintf("Error getting directory name from path: %s\n", path);
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sysfs_close_directory(sdir);
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return NULL;
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}
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strncpy(sdir->path, path, sizeof(sdir->path));
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return sdir;
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}
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/**
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* sysfs_open_link: opens a sysfs link, creates struct, and returns
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* @path: path of link to open.
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* returns: struct sysfs_link * with success and NULL on error.
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*/
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struct sysfs_link *sysfs_open_link(const unsigned char *linkpath)
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{
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struct sysfs_link *ln = NULL;
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if (linkpath == NULL || strlen(linkpath) > SYSFS_PATH_MAX) {
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errno = EINVAL;
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return NULL;
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}
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ln = alloc_link();
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if (ln == NULL) {
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dprintf("Error allocating link %s\n", linkpath);
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return NULL;
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}
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strcpy(ln->path, linkpath);
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if ((sysfs_get_name_from_path(linkpath, ln->name, SYSFS_NAME_LEN)) != 0
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|| (sysfs_get_link(linkpath, ln->target, SYSFS_PATH_MAX)) != 0) {
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errno = EINVAL;
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dprintf("Invalid link path %s\n", linkpath);
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return NULL;
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}
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return ln;
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}
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/**
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* sysfs_read_directory: grabs attributes, links, and subdirectories
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* @sysdir: sysfs directory to open
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* returns 0 with success and -1 with error.
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*/
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int sysfs_read_directory(struct sysfs_directory *sysdir)
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{
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DIR *dir = NULL;
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struct dirent *dirent = NULL;
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struct stat astats;
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struct sysfs_attribute *attr = NULL;
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struct sysfs_directory *subdir = NULL;
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struct sysfs_link *ln = NULL;
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unsigned char file_path[SYSFS_PATH_MAX];
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int retval = 0;
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if (sysdir == NULL) {
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errno = EINVAL;
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return -1;
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}
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dir = opendir(sysdir->path);
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if (dir == NULL) {
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dprintf("Error opening directory %s\n", sysdir->path);
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return -1;
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}
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while(((dirent = readdir(dir)) != NULL) && retval == 0) {
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if (0 == strcmp(dirent->d_name, "."))
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continue;
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if (0 == strcmp(dirent->d_name, ".."))
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continue;
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memset(file_path, 0, SYSFS_PATH_MAX);
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strncpy(file_path, sysdir->path, sizeof(file_path));
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strncat(file_path, "/", sizeof(file_path));
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strncat(file_path, dirent->d_name, sizeof(file_path));
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if ((lstat(file_path, &astats)) != 0) {
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dprintf("stat failed\n");
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continue;
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}
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if (S_ISREG(astats.st_mode)) {
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attr = sysfs_open_attribute(file_path);
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if (attr == NULL) {
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dprintf("Error opening attribute %s\n",
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file_path);
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retval = -1;
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break;
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}
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if (attr->method & SYSFS_METHOD_SHOW) {
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if ((sysfs_read_attribute(attr)) != 0) {
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dprintf("Error reading attribute %s\n",
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file_path);
|
|
sysfs_close_attribute(attr);
|
|
continue;
|
|
}
|
|
}
|
|
|
|
if (sysdir->attributes == NULL) {
|
|
sysdir->attributes = dlist_new_with_delete
|
|
(sizeof(struct sysfs_attribute),
|
|
sysfs_del_attribute);
|
|
}
|
|
dlist_unshift(sysdir->attributes, attr);
|
|
} else if (S_ISDIR(astats.st_mode)) {
|
|
subdir = sysfs_open_directory(file_path);
|
|
if (subdir == NULL) {
|
|
dprintf("Error opening directory %s\n",
|
|
file_path);
|
|
retval = -1;
|
|
break;
|
|
}
|
|
if (sysdir->subdirs == NULL)
|
|
sysdir->subdirs = dlist_new_with_delete
|
|
(sizeof(struct sysfs_directory),
|
|
sysfs_del_directory);
|
|
dlist_unshift(sysdir->subdirs, subdir);
|
|
} else if (S_ISLNK(astats.st_mode)) {
|
|
ln = sysfs_open_link(file_path);
|
|
if (ln == NULL) {
|
|
dprintf("Error opening link %s\n", file_path);
|
|
retval = -1;
|
|
break;
|
|
}
|
|
if (sysdir->links == NULL)
|
|
sysdir->links = dlist_new_with_delete
|
|
(sizeof(struct sysfs_link),
|
|
sysfs_del_link);
|
|
dlist_unshift(sysdir->links, ln);
|
|
}
|
|
}
|
|
closedir(dir);
|
|
return(retval);
|
|
}
|
|
|
|
/**
|
|
* sysfs_get_directory_attribute: retrieves attribute attrname
|
|
* @dir: directory to retrieve attribute from
|
|
* @attrname: name of attribute to look for
|
|
* returns sysfs_attribute if found and NULL if not found
|
|
*/
|
|
struct sysfs_attribute *sysfs_get_directory_attribute
|
|
(struct sysfs_directory *dir, unsigned char *attrname)
|
|
{
|
|
struct sysfs_directory *sdir = NULL;
|
|
struct sysfs_attribute *attr = NULL;
|
|
|
|
if (dir == NULL || attrname == NULL) {
|
|
errno = EINVAL;
|
|
return NULL;
|
|
}
|
|
|
|
attr = (struct sysfs_attribute *)dlist_find_custom(dir->attributes,
|
|
attrname, dir_attribute_name_equal);
|
|
if (attr != NULL)
|
|
return attr;
|
|
|
|
if (dir->subdirs != NULL) {
|
|
dlist_for_each_data(dir->subdirs, sdir,
|
|
struct sysfs_directory) {
|
|
if (sdir->attributes == NULL)
|
|
continue;
|
|
attr = sysfs_get_directory_attribute(sdir, attrname);
|
|
if (attr != NULL)
|
|
return attr;
|
|
}
|
|
}
|
|
return NULL;
|
|
}
|
|
|
|
/**
|
|
* sysfs_get_directory_link: retrieves link from one directory list
|
|
* @dir: directory to retrieve link from
|
|
* @linkname: name of link to look for
|
|
* returns reference to sysfs_link if found and NULL if not found
|
|
*/
|
|
struct sysfs_link *sysfs_get_directory_link
|
|
(struct sysfs_directory *dir, unsigned char *linkname)
|
|
{
|
|
if (dir == NULL || linkname == NULL) {
|
|
errno = EINVAL;
|
|
return NULL;
|
|
}
|
|
return (struct sysfs_link *)dlist_find_custom(dir->links,
|
|
linkname, dir_link_name_equal);
|
|
}
|
|
|
|
/**
|
|
* sysfs_get_subdirectory: retrieves subdirectory by name.
|
|
* @dir: directory to search for subdirectory.
|
|
* @subname: subdirectory name to get.
|
|
* returns reference to subdirectory or NULL if not found
|
|
*/
|
|
struct sysfs_directory *sysfs_get_subdirectory(struct sysfs_directory *dir,
|
|
unsigned char *subname)
|
|
{
|
|
struct sysfs_directory *sub = NULL, *cursub = NULL;
|
|
|
|
if (dir == NULL || dir->subdirs == NULL || subname == NULL) {
|
|
errno = EINVAL;
|
|
return NULL;
|
|
}
|
|
sub = (struct sysfs_directory *)dlist_find_custom(dir->subdirs,
|
|
subname, dir_subdir_name_equal);
|
|
if (sub != NULL)
|
|
return sub;
|
|
|
|
if (dir->subdirs != NULL) {
|
|
dlist_for_each_data(dir->subdirs, cursub,
|
|
struct sysfs_directory) {
|
|
if (cursub->subdirs == NULL)
|
|
continue;
|
|
sub = sysfs_get_subdirectory(cursub, subname);
|
|
if (sub != NULL)
|
|
return sub;
|
|
}
|
|
}
|
|
return NULL;
|
|
}
|
|
|
|
/**
|
|
* sysfs_get_subdirectory_link: looks through all subdirs for specific link.
|
|
* @dir: directory and subdirectories to search for link.
|
|
* @linkname: link name to get.
|
|
* returns reference to link or NULL if not found
|
|
*/
|
|
struct sysfs_link *sysfs_get_subdirectory_link(struct sysfs_directory *dir,
|
|
unsigned char *linkname)
|
|
{
|
|
struct sysfs_directory *cursub = NULL;
|
|
struct sysfs_link *ln = NULL;
|
|
|
|
if (dir == NULL || dir->links == NULL || linkname == NULL) {
|
|
errno = EINVAL;
|
|
return NULL;
|
|
}
|
|
|
|
ln = sysfs_get_directory_link(dir, linkname);
|
|
if (ln != NULL)
|
|
return ln;
|
|
|
|
if (dir->subdirs == NULL)
|
|
return NULL;
|
|
|
|
if (dir->subdirs != NULL) {
|
|
dlist_for_each_data(dir->subdirs, cursub,
|
|
struct sysfs_directory) {
|
|
if (cursub->subdirs == NULL)
|
|
continue;
|
|
ln = sysfs_get_subdirectory_link(cursub, linkname);
|
|
if (ln != NULL)
|
|
return ln;
|
|
}
|
|
}
|
|
return NULL;
|
|
}
|