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/*
* Copyright (C) 2008 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <stdio.h>
#include <string.h>
#include <fcntl.h>
#include <unistd.h>
#include <malloc.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
void *read_file(char *filename, ssize_t *_size)
{
int ret, fd;
struct stat sb;
ssize_t size;
void *buffer = NULL;
/* open the file */
fd = open(filename, O_RDONLY);
if (fd < 0)
return NULL;
/* find out how big it is */
if (fstat(fd, &sb) < 0)
goto bail;
size = sb.st_size;
/* allocate memory for it to be read into */
buffer = malloc(size);
if (!buffer)
goto bail;
/* slurp it into our buffer */
ret = read(fd, buffer, size);
if (ret != size)
goto bail;
/* let the caller know how big it is */
*_size = size;
bail:
close(fd);
return buffer;
}
char *truncate_sysfs_path(char *path, int num_elements_to_remove, char *buffer, int buffer_size)
{
int i;
strncpy(buffer, path, buffer_size);
for (i = 0; i < num_elements_to_remove; i++) {
char *p = &buffer[strlen(buffer)-1];
for (p = &buffer[strlen(buffer) -1]; *p != '/'; p--);
*p = '\0';
}
return buffer;
}
char *read_sysfs_var(char *buffer, size_t maxlen, char *devpath, char *var)
{
char filename[255];
char *p;
ssize_t sz;
snprintf(filename, sizeof(filename), "/sys%s/%s", devpath, var);
p = read_file(filename, &sz);
p[(strlen(p) - 1)] = '\0';
strncpy(buffer, p, maxlen);
free(p);
return buffer;
}
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