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