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/*
* Check decoding of clone flags.
*
* Copyright (c) 2017-2025 The strace developers.
* All rights reserved.
*
* SPDX-License-Identifier: GPL-2.0-or-later
*/
#include "tests.h"
#include "xmalloc.h"
#include <errno.h>
#include <limits.h>
#include <sched.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/wait.h>
#include <unistd.h>
#include <linux/sched.h>
static const int child_exit_status = 42;
static pid_t pid;
static void
retrieve_userns(pid_t pid, char *userns_buf, size_t userns_buflen)
{
char *fname = xasprintf("/proc/%d/ns/user", pid);
ssize_t rc = readlink(fname, userns_buf, userns_buflen - 1);
if (rc < 0) {
perror(fname);
userns_buf[0] = '\0';
} else if ((size_t) rc >= userns_buflen)
error_msg_and_fail("readlink: %s: result is too long", fname);
else
userns_buf[rc] = '\0';
free(fname);
}
static pid_t
wait_cloned(pid_t pid, int sig, const char *text, char *userns_buf, size_t userns_buflen)
{
if (pid < 0) {
if (userns_buf) {
/*
* Creating user namespaces can be disabled,
* and it would be undesirable to skip the
* whole test because of that. Let's just
* return pid here.
*/
return pid;
}
perror_msg_and_fail("clone %s", text);
}
if (userns_buf)
retrieve_userns(pid, userns_buf, userns_buflen);
int status;
pid_t rc = wait(&status);
if (sig) {
if (rc != pid)
perror_msg_and_fail("unexpected wait rc %d from %s",
rc, text);
if (!WIFEXITED(status) ||
WEXITSTATUS(status) != child_exit_status)
error_msg_and_fail("unexpected wait status %#x from %s",
status, text);
} else {
if (rc >= 0)
error_msg_and_fail("unexpected wait rc %d from %s",
rc, text);
}
return pid;
}
#ifdef IA64
extern int __clone2(int (*)(void *), void *, size_t, int, void *, ...);
# define do_clone(fn_, stack_, size_, flags_, arg_, ...) \
wait_cloned(__clone2((fn_), (stack_), (size_), (flags_), (arg_), \
## __VA_ARGS__), (flags_) & 0xff, #flags_, NULL, 0)
# define do_clone_newns(userns_buf_, fn_, stack_, size_, flags_, arg_, ...) \
wait_cloned(__clone2((fn_), (stack_), (size_), (flags_), (arg_), \
## __VA_ARGS__), (flags_) & 0xff, #flags_, userns_buf_, sizeof(userns_buf_))
# define SYSCALL_NAME "clone2"
# define STACK_SIZE_FMT ", stack_size=%#lx"
# define STACK_SIZE_ARG child_stack_size,
#else
# define do_clone(fn_, stack_, size_, flags_, arg_, ...) \
wait_cloned(clone((fn_), (stack_), (flags_), (arg_), \
## __VA_ARGS__), (flags_) & 0xff, #flags_, NULL, 0)
# define do_clone_newns(userns_buf_, fn_, stack_, size_, flags_, arg_, ...) \
wait_cloned(clone((fn_), (stack_), (flags_), (arg_), \
## __VA_ARGS__), (flags_) & 0xff, #flags_, userns_buf_, sizeof(userns_buf_))
# define SYSCALL_NAME "clone"
# define STACK_SIZE_FMT ""
# define STACK_SIZE_ARG
#endif
static int
child(void *const arg)
{
return child_exit_status;
}
int
main(void)
{
const unsigned long child_stack_size = get_page_size();
void *const child_stack =
tail_alloc(child_stack_size * 2) + child_stack_size;
const char *child_stack_expected_str = getenv("CHILD_STACK_EXPECTED");
const char *child_stack_reported_str = getenv("CHILD_STACK_REPORTED");
if (!child_stack_expected_str || !child_stack_reported_str) {
const unsigned long child_stack_base =
(unsigned long) child_stack / 0x1000;
pid = do_clone(child, child_stack, child_stack_size,
SIGCHLD, 0);
printf("%s\\(child_stack=(%#lx|%#lx)[[:xdigit:]]{3}"
STACK_SIZE_FMT ", flags=%s\\) = %d\n",
SYSCALL_NAME, child_stack_base, child_stack_base - 1,
STACK_SIZE_ARG "SIGCHLD", pid);
return 0;
}
const unsigned long child_stack_expected =
strtoul(child_stack_expected_str, 0, 16);
const unsigned long child_stack_reported =
strtoul(child_stack_reported_str, 0, 16);
const unsigned long child_stack_printed =
(unsigned long) child_stack +
(child_stack_reported - child_stack_expected);
pid = do_clone(child, child_stack, child_stack_size, 0, 0);
printf("%s(child_stack=%#lx" STACK_SIZE_FMT ", flags=%s) = %d\n",
SYSCALL_NAME, child_stack_printed, STACK_SIZE_ARG
"0", pid);
pid = do_clone(child, child_stack, child_stack_size, CLONE_FS, 0);
printf("%s(child_stack=%#lx" STACK_SIZE_FMT ", flags=%s) = %d\n",
SYSCALL_NAME, child_stack_printed, STACK_SIZE_ARG
"CLONE_FS", pid);
pid = do_clone(child, child_stack, child_stack_size, SIGCHLD, 0);
printf("%s(child_stack=%#lx" STACK_SIZE_FMT ", flags=%s) = %d\n",
SYSCALL_NAME, child_stack_printed, STACK_SIZE_ARG
"SIGCHLD", pid);
pid = do_clone(child, child_stack, child_stack_size,
CLONE_FS|SIGCHLD, 0);
printf("%s(child_stack=%#lx" STACK_SIZE_FMT ", flags=%s) = %d\n",
SYSCALL_NAME, child_stack_printed, STACK_SIZE_ARG
"CLONE_FS|SIGCHLD", pid);
TAIL_ALLOC_OBJECT_CONST_PTR(pid_t, ptid);
pid = do_clone(child, child_stack, child_stack_size,
CLONE_PARENT_SETTID|SIGCHLD, 0, ptid);
printf("%s(child_stack=%#lx" STACK_SIZE_FMT ", flags=%s"
", parent_tid=[%u]) = %d\n",
SYSCALL_NAME, child_stack_printed, STACK_SIZE_ARG
"CLONE_PARENT_SETTID|SIGCHLD", *ptid, pid);
char buf[PATH_MAX];
if (readlink("/proc/self/fd/0", buf, sizeof(buf) - 1) > 0) {
*ptid = 0;
pid = do_clone(child, child_stack, child_stack_size,
CLONE_PIDFD|SIGCHLD, 0, ptid);
char *fname = xasprintf("/proc/self/fd/%d", *ptid);
ssize_t rc = readlink(fname, buf, sizeof(buf) - 1);
if ((unsigned int) rc >= sizeof(buf))
perror_msg_and_fail("readlink: %s", fname);
buf[rc] = '\0';
printf("%s(child_stack=%#lx" STACK_SIZE_FMT ", flags=%s"
", parent_tid=[%u<%s>]) = %d\n",
SYSCALL_NAME, child_stack_printed, STACK_SIZE_ARG
"CLONE_PIDFD|SIGCHLD", *ptid, buf, pid);
}
pid = do_clone_newns(buf, child_stack, child_stack, child_stack_size,
CLONE_NEWUSER, 0);
printf("%s(child_stack=%#lx" STACK_SIZE_FMT ", flags=%s) = ",
SYSCALL_NAME, child_stack_printed, STACK_SIZE_ARG
"CLONE_NEWUSER");
if (pid < 0)
printf("%s\n", sprintrc(pid));
else if (buf[0])
printf("%d (%s)\n", pid, buf);
else
printf("%d\n", pid);
return 0;
}
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