49 lines · c
1// SPDX-License-Identifier: GPL-2.02/*3 * Author: SeongJae Park <sj@kernel.org>4 */5 6#include <fcntl.h>7#include <stdlib.h>8#include <unistd.h>9#include <stdio.h>10 11#pragma GCC diagnostic push12#if __GNUC__ >= 11 && __GNUC_MINOR__ >= 113/* Ignore read(2) overflow and write(2) overread compile warnings */14#pragma GCC diagnostic ignored "-Wstringop-overread"15#pragma GCC diagnostic ignored "-Wstringop-overflow"16#endif17 18void write_read_with_huge_count(char *file)19{20 int filedesc = open(file, O_RDWR);21 char buf[25];22 int ret;23 24 printf("%s %s\n", __func__, file);25 if (filedesc < 0) {26 fprintf(stderr, "failed opening %s\n", file);27 exit(1);28 }29 30 write(filedesc, "", 0xfffffffful);31 perror("after write: ");32 ret = read(filedesc, buf, 0xfffffffful);33 perror("after read: ");34 close(filedesc);35}36 37#pragma GCC diagnostic pop38 39int main(int argc, char *argv[])40{41 if (argc != 2) {42 fprintf(stderr, "Usage: %s <file>\n", argv[0]);43 exit(1);44 }45 write_read_with_huge_count(argv[1]);46 47 return 0;48}49