// SPDX-License-Identifier: GPL-2.0-only/* * Intel MIC Platform Software Stack (MPSS) * * Copyright(c) 2013 Intel Corporation. * * Intel MIC User Space Tools. */ #include "mpssd.h" #define PAGE_SIZE 4096 char *readsysfs(char *dir, char *entry){	char filename[PATH_MAX];	char value[PAGE_SIZE];	char *string = NULL;	int fd;	int len; 	if (dir == NULL)		snprintf(filename, PATH_MAX, "%s/%s", MICSYSFSDIR, entry);	else		snprintf(filename, PATH_MAX,			 "%s/%s/%s", MICSYSFSDIR, dir, entry); 	fd = open(filename, O_RDONLY);	if (fd < 0) {		mpsslog("Failed to open sysfs entry '%s': %s\n",			filename, strerror(errno));		return NULL;	} 	len = read(fd, value, sizeof(value));	if (len < 0) {		mpsslog("Failed to read sysfs entry '%s': %s\n",			filename, strerror(errno));		goto readsys_ret;	}	if (len == 0)		goto readsys_ret; 	value[len - 1] = '\0'; 	string = malloc(strlen(value) + 1);	if (string)		strcpy(string, value); readsys_ret:	close(fd);	return string;} intsetsysfs(char *dir, char *entry, char *value){	char filename[PATH_MAX];	char *oldvalue;	int fd, ret = 0; 	if (dir == NULL)		snprintf(filename, PATH_MAX, "%s/%s", MICSYSFSDIR, entry);	else		snprintf(filename, PATH_MAX, "%s/%s/%s",			 MICSYSFSDIR, dir, entry); 	oldvalue = readsysfs(dir, entry); 	fd = open(filename, O_RDWR);	if (fd < 0) {		ret = errno;		mpsslog("Failed to open sysfs entry '%s': %s\n",			filename, strerror(errno));		goto done;	} 	if (!oldvalue || strcmp(value, oldvalue)) {		if (write(fd, value, strlen(value)) < 0) {			ret = errno;			mpsslog("Failed to write new sysfs entry '%s': %s\n",				filename, strerror(errno));		}	}	close(fd);done:	if (oldvalue)		free(oldvalue);	return ret;}