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