// SPDX-License-Identifier: GPL-2.0
#define _GNU_SOURCE
#include <assert.h>
#include <errno.h>
#include <fcntl.h>
#include <linux/types.h>
#include <sched.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <syscall.h>
#include <sys/wait.h>
#include <sys/mman.h>
#include "pidfd.h"
#include "../kselftest.h"
struct error {
int code;
char msg[512];
};
static int error_set(struct error *err, int code, const char *fmt, ...)
{
va_list args;
int r;
if (code == PIDFD_PASS || !err || err->code != PIDFD_PASS)
return code;
err->code = code;
va_start(args, fmt);
r = vsnprintf(err->msg, sizeof(err->msg), fmt, args);
assert((size_t)r < sizeof(err->msg));
va_end(args);
return code;
}
static void error_report(struct error *err, const char *test_name)
{
switch (err->code) {
case PIDFD_ERROR:
ksft_exit_fail_msg("%s test: Fatal: %s\n", test_name, err->msg);
break;
case PIDFD_FAIL:
/* will be: not ok %d # error %s test: %s */
ksft_test_result_error("%s test: %s\n", test_name, err->msg);
break;
case PIDFD_SKIP:
/* will be: not ok %d # SKIP %s test: %s */
ksft_test_result_skip("%s test: %s\n", test_name, err->msg);
break;
case PIDFD_XFAIL:
ksft_test_result_pass("%s test: Expected failure: %s\n",
test_name, err->msg);
break;
case PIDFD_PASS:
ksft_test_result_pass("%s test: Passed\n", test_name);
break;
default:
ksft_exit_fail_msg("%s test: Unknown code: %d %s\n",
test_name, err->code, err->msg);
break;
}
}
static inline int error_check(struct error *err, const char *test_name)
{
/* In case of error we bail out and terminate the test program */
if (err->code == PIDFD_ERROR)
error_report(err, test_name);
return err->code;
}
#define CHILD_STACK_SIZE 8192
struct child {
char *stack;
pid_t pid;
int fd;
};
static struct child clone_newns(int (*fn)(void *), void *args,
struct error *err)
{
static int flags = CLONE_PIDFD | CLONE_NEWPID | CLONE_NEWNS | SIGCHLD;
struct child ret;
if (!(flags & CLONE_NEWUSER) && geteuid() != 0)
flags |= CLONE_NEWUSER;
ret.stack = mmap(NULL, CHILD_STACK_SIZE, PROT_READ | PROT_WRITE,
MAP_PRIVATE | MAP_ANONYMOUS | MAP_STACK, -1, 0);
if (ret.stack == MAP_FAILED) {
error_set(err, -1, "mmap of stack failed (errno %d)", errno);
return ret;
}
#ifdef __ia64__
ret.pid = __clone2(fn, ret.stack, CHILD_STACK_SIZE, flags, args, &ret.fd);
#else
ret.pid = clone(fn, ret.stack + CHILD_STACK_SIZE, flags, args, &ret.fd);
#endif
if (ret.pid < 0) {
error_set(err, PIDFD_ERROR, "clone failed (ret %d, errno %d)",
ret.fd, errno);
return ret;
}
ksft_print_msg("New child: %d, fd: %d\n", ret.pid, ret.fd);
return ret;
}
static inline void child_close(struct child *child)
{
close(child->fd);
}
static inline int child_join(struct child *child, struct error *err)
{
int r;
r = wait_for_pid(child->pid);
if (r < 0)
error_set(err, PIDFD_ERROR, "waitpid failed (ret %d, errno %d)",
r, errno);
else if (r > 0)
error_set(err, r, "child %d reported: %d", child->pid, r);
if (munmap(child->stack, CHILD_STACK_SIZE)) {
error_set(err, -1, "munmap of child stack failed (errno %d)", errno);
r = -1;
}
ksft_print_msg("waitpid WEXITSTATUS=%d\n", r);
return r;
}
static inline int child_join_close(struct child *child, struct error *err)
{
child_close(child);
return child_join(child, err);
}
static inline void trim_newline(char *str)
{
char *pos = strrchr(str, '\n');
if (pos)
*pos = '\0';
}
static int verify_fdinfo(int pidfd, struct error *err, const char *prefix,
size_t prefix_len, const char *expect, ...)
{
char buffer[512] = {0, };
char path[512] = {0, };
va_list args;
FILE *f;
char *line = NULL;
size_t n = 0;
int found = 0;
int r;
va_start(args, expect);
r = vsnprintf(buffer, sizeof(buffer), expect, args);
assert((size_t)r < sizeof(buffer));
va_end(args);
snprintf(path, sizeof(path), "/proc/self/fdinfo/%d", pidfd);
f = fopen(path, "re");
if (!f)
return error_set(err, PIDFD_ERROR, "fdinfo open failed for %d",
pidfd);
while (getline(&line, &n, f) != -1) {
char *val;
if (strncmp(line, prefix, prefix_len))
continue;
found = 1;
val = line + prefix_len;
r = strcmp(val, buffer);
if (r != 0) {
trim_newline(line);
trim_newline(buffer);
error_set(err, PIDFD_FAIL, "%s '%s' != '%s'",
prefix, val, buffer);
}
break;
}
free(line);
fclose(f);
if (found == 0)
return error_set(err, PIDFD_FAIL, "%s not found for fd %d",
prefix, pidfd);
return PIDFD_PASS;
}
static int child_fdinfo_nspid_test(void *args)
{
struct error err;
int pidfd;
int r;
/* if we got no fd for the sibling, we are done */
if (!args)
return PIDFD_PASS;
/* verify that we can not resolve the pidfd for a process
* in a sibling pid namespace, i.e. a pid namespace it is
* not in our or a descended namespace
*/
r = mount(NULL, "/", NULL, MS_REC | MS_PRIVATE, 0);
if (r < 0) {
ksft_print_msg("Failed to remount / private\n");
return PIDFD_ERROR;
}
(void)umount2("/proc", MNT_DETACH);
r = mount("proc", "/proc", "proc", 0, NULL);
if (r < 0) {
ksft_print_msg("Failed to remount /proc\n");
return PIDFD_ERROR;
}
pidfd = *(int *)args;
r = verify_fdinfo(pidfd, &err, "NSpid:", 6, "\t0\n");
if (r != PIDFD_PASS)
ksft_print_msg("NSpid fdinfo check failed: %s\n", err.msg);
return r;
}
static void test_pidfd_fdinfo_nspid(void)
{
struct child a, b;
struct error err = {0, };
const char *test_name = "pidfd check for NSpid in fdinfo";
/* Create a new child in a new pid and mount namespace */
a = clone_newns(child_fdinfo_nspid_test, NULL, &err);
error_check(&err, test_name);
/* Pass the pidfd representing the first child to the
* second child, which will be in a sibling pid namespace,
* which means that the fdinfo NSpid entry for the pidfd
* should only contain '0'.
*/
b = clone_newns(child_fdinfo_nspid_test, &a.fd, &err);
error_check(&err, test_name);
/* The children will have pid 1 in the new pid namespace,
* so the line must be 'NSPid:\t<pid>\t1'.
*/
verify_fdinfo(a.fd, &err, "NSpid:", 6, "\t%d\t%d\n", a.pid, 1);
verify_fdinfo(b.fd, &err, "NSpid:", 6, "\t%d\t%d\n", b.pid, 1);
/* wait for the process, check the exit status and set
* 'err' accordingly, if it is not already set.
*/
child_join_close(&a, &err);
child_join_close(&b, &err);
error_report(&err, test_name);
}
static void test_pidfd_dead_fdinfo(void)
{
struct child a;
struct error err = {0, };
const char *test_name = "pidfd check fdinfo for dead process";
/* Create a new child in a new pid and mount namespace */
a = clone_newns(child_fdinfo_nspid_test, NULL, &err);
error_check(&err, test_name);
child_join(&a, &err);
verify_fdinfo(a.fd, &err, "Pid:", 4, "\t-1\n");
verify_fdinfo(a.fd, &err, "NSpid:", 6, "\t-1\n");
child_close(&a);
error_report(&err, test_name);
}
int main(int argc, char **argv)
{
ksft_print_header();
ksft_set_plan(2);
test_pidfd_fdinfo_nspid();
test_pidfd_dead_fdinfo();
ksft_exit_pass();
}
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