| |
| /* |
| * 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; |
| } |
| |