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/* SPDX-License-Identifier: GPL-2.0 */
/*
* Copyright (c) 2024 Meta Platforms, Inc. and affiliates.
* Copyright (c) 2024 David Vernet <dvernet@meta.com>
*/
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
/* Returns read len on success, or -errno on failure. */
static ssize_t read_text(const char *path, char *buf, size_t max_len)
{
ssize_t len;
int fd;
fd = open(path, O_RDONLY);
if (fd < 0)
return -errno;
len = read(fd, buf, max_len - 1);
if (len >= 0)
buf[len] = 0;
close(fd);
return len < 0 ? -errno : len;
}
/* Returns written len on success, or -errno on failure. */
static ssize_t write_text(const char *path, char *buf, ssize_t len)
{
int fd;
ssize_t written;
fd = open(path, O_WRONLY | O_APPEND);
if (fd < 0)
return -errno;
written = write(fd, buf, len);
close(fd);
return written < 0 ? -errno : written;
}
long file_read_long(const char *path)
{
char buf[128];
if (read_text(path, buf, sizeof(buf)) <= 0)
return -1;
return atol(buf);
}
int file_write_long(const char *path, long val)
{
char buf[64];
int ret;
ret = sprintf(buf, "%lu", val);
if (ret < 0)
return ret;
if (write_text(path, buf, sizeof(buf)) <= 0)
return -1;
return 0;
}
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