107 lines · c
1// SPDX-License-Identifier: GPL-2.02 3#include <errno.h>4#include <stdbool.h>5#include <stdio.h>6#include <stdlib.h>7#include <string.h>8#include <sys/stat.h>9#include <unistd.h>10#include <linux/limits.h>11 12#include "../kselftest.h"13 14#define MIN_TTY_PATH_LEN 815 16static bool tty_valid(char *tty)17{18 if (strlen(tty) < MIN_TTY_PATH_LEN)19 return false;20 21 if (strncmp(tty, "/dev/tty", MIN_TTY_PATH_LEN) == 0 ||22 strncmp(tty, "/dev/pts", MIN_TTY_PATH_LEN) == 0)23 return true;24 25 return false;26}27 28static int write_dev_tty(void)29{30 FILE *f;31 int r = 0;32 33 f = fopen("/dev/tty", "r+");34 if (!f)35 return -errno;36 37 r = fprintf(f, "hello, world!\n");38 if (r != strlen("hello, world!\n"))39 r = -EIO;40 41 fclose(f);42 return r;43}44 45int main(int argc, char **argv)46{47 int r;48 char tty[PATH_MAX] = {};49 struct stat st1, st2;50 int result = KSFT_FAIL;51 52 ksft_print_header();53 ksft_set_plan(1);54 55 r = readlink("/proc/self/fd/0", tty, PATH_MAX);56 if (r < 0) {57 ksft_print_msg("readlink on /proc/self/fd/0 failed: %m\n");58 goto out;59 }60 61 if (!tty_valid(tty)) {62 ksft_print_msg("invalid tty path '%s'\n", tty);63 result = KSFT_SKIP;64 goto out;65 66 }67 68 r = stat(tty, &st1);69 if (r < 0) {70 ksft_print_msg("stat failed on tty path '%s': %m\n", tty);71 goto out;72 }73 74 /* We need to wait at least 8 seconds in order to observe timestamp change */75 /* https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=fbf47635315ab308c9b58a1ea0906e711a9228de */76 sleep(10);77 78 r = write_dev_tty();79 if (r < 0) {80 ksft_print_msg("failed to write to /dev/tty: %s\n",81 strerror(-r));82 goto out;83 }84 85 r = stat(tty, &st2);86 if (r < 0) {87 ksft_print_msg("stat failed on tty path '%s': %m\n", tty);88 goto out;89 }90 91 /* We wrote to the terminal so timestamps should have been updated */92 if (st1.st_atim.tv_sec == st2.st_atim.tv_sec &&93 st1.st_mtim.tv_sec == st2.st_mtim.tv_sec) {94 ksft_print_msg("tty timestamps not updated\n");95 goto out;96 }97 98 ksft_print_msg(99 "timestamps of terminal '%s' updated after write to /dev/tty\n", tty);100 result = KSFT_PASS;101 102out:103 ksft_test_result_report(result, "tty_tstamp_update\n");104 105 ksft_finished();106}107