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/*
* write_attr.c
*
* Utility to modify the value of a given class device attribute
*
* Copyright (C) IBM Corp. 2003
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation version 2 of the License.
*
* This program 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
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 675 Mass Ave, Cambridge, MA 02139, USA.
*
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "libsysfs.h"
static void print_usage(void)
{
fprintf(stdout, "Usage: write_attr [classname] [device] [attribute] [new_value]\n");
}
int main(int argc, char *argv[])
{
struct sysfs_attribute *attr = NULL;
if (argc != 5) {
print_usage();
return 1;
}
attr = sysfs_open_classdev_attr(argv[1], argv[2], argv[3]);
if (attr == NULL) {
fprintf(stdout, "Attribute %s not defined for classdev %s\n",
argv[3], argv[2]);
return 1;
}
fprintf(stdout, "Attribute %s presently has a value %s\n",
attr->name, attr->value);
if ((sysfs_write_attribute(attr, argv[4], strlen(argv[4]))) != 0) {
fprintf(stdout, "Error writing attribute value\n");
sysfs_close_attribute(attr);
return 1;
}
fprintf(stdout, "Attribute value after write is %s\n", attr->value);
sysfs_close_attribute(attr);
return 0;
}
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