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