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/*
* Check corner cases of AT_FDCWD path decoding.
*
* Copyright (c) 2021 The strace developers.
* All rights reserved.
*
* SPDX-License-Identifier: GPL-2.0-or-later
*/
#include "tests.h"
#include "scno.h"
#include <fcntl.h>
#include <limits.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <sys/stat.h>
#include <sys/types.h>
/*
* This test is designed to cover cases where AT_FDCWD path decoding
* cannot happen because paths length exceed PATH_MAX.
* It should be executed with -y or a similar option.
*/
int main(void)
{
/*
* Make sure the current workdir of the tracee
* is different from the current workdir of the tracer.
*/
create_and_enter_subdir("pathmax_subdir");
char *topdir = get_fd_path(get_dir_fd("."));
/*
* AT_FDCWD path decoding
*/
char name[NAME_MAX + 1];
memset(name, 'x', sizeof(name) - 1);
name[sizeof(name) - 1] = '\0';
unsigned int count = 0;
for (size_t len = strlen(topdir);
len <= PATH_MAX;
len += sizeof(name), ++count) {
if (mkdir(name, 0700))
perror_msg_and_fail("mkdir, count=%u", count);
if (chdir(name))
perror_msg_and_fail("chdir, count=%u", count);
}
/* AT_FDCWD is not be printed since path cannot be resolved. */
int fd = syscall(__NR_openat, AT_FDCWD, "sample", O_RDONLY);
printf("openat(AT_FDCWD, \"sample\", O_RDONLY) = %s\n",
sprintrc(fd));
/* Go back one dir and verify it's printed. */
--count;
if (chdir(".."))
perror_msg_and_fail("chdir");
if (rmdir(name))
perror_msg_and_fail("rmdir");
char *cwd = get_fd_path(get_dir_fd("."));
fd = syscall(__NR_openat, AT_FDCWD, "sample", O_RDONLY);
printf("openat(AT_FDCWD<%s>, \"sample\", O_RDONLY) = %s\n",
cwd, sprintrc(fd));
/* Create a dir for which exact PATH_MAX size is returned. */
char dir[NAME_MAX + 1];
memset(dir, 'x', sizeof(dir) - 1);
dir[PATH_MAX - (strlen(cwd) + 1)] = '\0';
if (mkdir(dir, 0700))
perror_msg_and_fail("mkdir");
if (chdir(dir))
perror_msg_and_fail("chdir");
/* AT_FDCWD is not printed since path cannot be resolved fully. */
fd = syscall(__NR_openat, AT_FDCWD, "sample", O_RDONLY);
printf("openat(AT_FDCWD, \"sample\", O_RDONLY) = %s\n",
sprintrc(fd));
if (chdir(".."))
perror_msg_and_fail("chdir");
if (rmdir(dir))
perror_msg_and_fail("rmdir");
for (; count > 0; --count) {
if (chdir(".."))
perror_msg_and_fail("chdir, count=%u", count);
if (rmdir(name))
perror_msg_and_fail("rmdir, count=%u", count);
}
leave_and_remove_subdir();
puts("+++ exited with 0 +++");
return 0;
}
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