1 // SPDX-License-Identifier: GPL-2.0
10 #include <linux/limits.h>
12 #include "../kselftest.h"
14 #define MIN_TTY_PATH_LEN 8
16 static bool tty_valid(char *tty)
18 if (strlen(tty) < MIN_TTY_PATH_LEN)
21 if (strncmp(tty, "/dev/tty", MIN_TTY_PATH_LEN) == 0 ||
22 strncmp(tty, "/dev/pts", MIN_TTY_PATH_LEN) == 0)
28 static int write_dev_tty(void)
33 f = fopen("/dev/tty", "r+");
37 r = fprintf(f, "hello, world!\n");
38 if (r != strlen("hello, world!\n"))
45 int main(int argc, char **argv)
48 char tty[PATH_MAX] = {};
54 r = readlink("/proc/self/fd/0", tty, PATH_MAX);
56 ksft_exit_fail_msg("readlink on /proc/self/fd/0 failed: %m\n");
59 ksft_exit_skip("invalid tty path '%s'\n", tty);
63 ksft_exit_fail_msg("stat failed on tty path '%s': %m\n", tty);
65 /* We need to wait at least 8 seconds in order to observe timestamp change */
66 /* https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=fbf47635315ab308c9b58a1ea0906e711a9228de */
71 ksft_exit_fail_msg("failed to write to /dev/tty: %s\n",
76 ksft_exit_fail_msg("stat failed on tty path '%s': %m\n", tty);
78 /* We wrote to the terminal so timestamps should have been updated */
79 if (st1.st_atim.tv_sec == st2.st_atim.tv_sec &&
80 st1.st_mtim.tv_sec == st2.st_mtim.tv_sec) {
81 ksft_test_result_fail("tty timestamps not updated\n");
85 ksft_test_result_pass(
86 "timestamps of terminal '%s' updated after write to /dev/tty\n", tty);