failed approach

gomspace/libutil/src/linux/sysfs_helper.c

@@ -0,0 +1,48 @@
+/* Copyright (c) 2013-2017 GomSpace A/S. All rights reserved. */
+
+#include <gs/util/linux/sysfs_helper.h>
+#include <gs/util/log.h>
+
+#include <string.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <unistd.h>
+
+gs_error_t gs_sysfs_write_file(const char *path, const char *value)
+{
+    log_trace("sysfs: write %s to %s", value, path);
+
+    int fd = open(path, O_WRONLY);
+    if (fd < 0) {
+        return GS_ERROR_HANDLE;
+    }
+
+    size_t len = strlen(value);
+    ssize_t bytes = write(fd, value, len);
+    close(fd);
+    if (bytes < 0) {
+        return GS_ERROR_NO_DATA;
+    }
+
+    return (len == (size_t)bytes) ? GS_OK : GS_ERROR_NO_DATA;
+}
+
+gs_error_t gs_sysfs_read_file(const char *path, char *value, size_t len)
+{
+    log_trace("sysfs: read %s", path);
+
+    int fd = open(path, O_RDONLY);
+    if (fd < 0) {
+        return GS_ERROR_HANDLE;
+    }
+
+    ssize_t bytes = read(fd, value, len);
+    close(fd);
+    if (bytes < 0) {
+        return GS_ERROR_DATA;
+    }
+
+    return GS_OK;
+}