// SPDX-License-Identifier: GPL-2.0

#define _GNU_SOURCE
#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#include <linux/types.h>
#include <poll.h>
#include <sched.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <syscall.h>
#include <sys/prctl.h>
#include <sys/wait.h>
#include <unistd.h>
#include <sys/socket.h>
#include <linux/kcmp.h>
#include <sys/stat.h>

#include "pidfd.h"
#include "kselftest_harness.h"

FIXTURE(file_handle)
{
        pid_t pid;
        int pidfd;

        pid_t child_pid1;
        int child_pidfd1;

        pid_t child_pid2;
        int child_pidfd2;

        pid_t child_pid3;
        int child_pidfd3;
};

FIXTURE_SETUP(file_handle)
{
        int ret;
        int ipc_sockets[2];
        char c;

        self->pid = getpid();
        self->pidfd = sys_pidfd_open(self->pid, 0);
        ASSERT_GE(self->pidfd, 0);

        ret = socketpair(AF_LOCAL, SOCK_STREAM | SOCK_CLOEXEC, 0, ipc_sockets);
        EXPECT_EQ(ret, 0);

        self->child_pid1 = create_child(&self->child_pidfd1, CLONE_NEWUSER);
        EXPECT_GE(self->child_pid1, 0);

        if (self->child_pid1 == 0) {
                close(ipc_sockets[0]);

                if (write_nointr(ipc_sockets[1], "1", 1) < 0)
                        _exit(EXIT_FAILURE);

                close(ipc_sockets[1]);

                pause();
                _exit(EXIT_SUCCESS);
        }

        close(ipc_sockets[1]);
        ASSERT_EQ(read_nointr(ipc_sockets[0], &c, 1), 1);
        close(ipc_sockets[0]);

        ret = socketpair(AF_LOCAL, SOCK_STREAM | SOCK_CLOEXEC, 0, ipc_sockets);
        EXPECT_EQ(ret, 0);

        self->child_pid2 = create_child(&self->child_pidfd2, CLONE_NEWUSER | CLONE_NEWPID);
        EXPECT_GE(self->child_pid2, 0);

        if (self->child_pid2 == 0) {
                close(ipc_sockets[0]);

                if (write_nointr(ipc_sockets[1], "1", 1) < 0)
                        _exit(EXIT_FAILURE);

                close(ipc_sockets[1]);

                pause();
                _exit(EXIT_SUCCESS);
        }

        close(ipc_sockets[1]);
        ASSERT_EQ(read_nointr(ipc_sockets[0], &c, 1), 1);
        close(ipc_sockets[0]);

        ret = socketpair(AF_LOCAL, SOCK_STREAM | SOCK_CLOEXEC, 0, ipc_sockets);
        EXPECT_EQ(ret, 0);

        self->child_pid3 = create_child(&self->child_pidfd3, CLONE_NEWUSER | CLONE_NEWPID);
        EXPECT_GE(self->child_pid3, 0);

        if (self->child_pid3 == 0) {
                close(ipc_sockets[0]);

                if (write_nointr(ipc_sockets[1], "1", 1) < 0)
                        _exit(EXIT_FAILURE);

                close(ipc_sockets[1]);

                pause();
                _exit(EXIT_SUCCESS);
        }

        close(ipc_sockets[1]);
        ASSERT_EQ(read_nointr(ipc_sockets[0], &c, 1), 1);
        close(ipc_sockets[0]);
}

FIXTURE_TEARDOWN(file_handle)
{
        EXPECT_EQ(close(self->pidfd), 0);

        EXPECT_EQ(sys_pidfd_send_signal(self->child_pidfd1, SIGKILL, NULL, 0), 0);
        if (self->child_pidfd1 >= 0)
                EXPECT_EQ(0, close(self->child_pidfd1));

        EXPECT_EQ(sys_waitid(P_PID, self->child_pid1, NULL, WEXITED), 0);

        EXPECT_EQ(sys_pidfd_send_signal(self->child_pidfd2, SIGKILL, NULL, 0), 0);
        if (self->child_pidfd2 >= 0)
                EXPECT_EQ(0, close(self->child_pidfd2));

        EXPECT_EQ(sys_waitid(P_PID, self->child_pid2, NULL, WEXITED), 0);

        if (self->child_pidfd3 >= 0) {
                EXPECT_EQ(sys_pidfd_send_signal(self->child_pidfd3, SIGKILL, NULL, 0), 0);
                EXPECT_EQ(0, close(self->child_pidfd3));
                EXPECT_EQ(sys_waitid(P_PID, self->child_pid3, NULL, WEXITED), 0);
        }
}

/*
 * Test that we can decode a pidfs file handle in the same pid
 * namespace.
 */
TEST_F(file_handle, file_handle_same_pidns)
{
        int mnt_id;
        struct file_handle *fh;
        int pidfd = -EBADF;
        struct stat st1, st2;

        fh = malloc(sizeof(struct file_handle) + MAX_HANDLE_SZ);
        ASSERT_NE(fh, NULL);
        memset(fh, 0, sizeof(struct file_handle) + MAX_HANDLE_SZ);
        fh->handle_bytes = MAX_HANDLE_SZ;

        ASSERT_EQ(name_to_handle_at(self->child_pidfd1, "", fh, &mnt_id, AT_EMPTY_PATH), 0);

        ASSERT_EQ(fstat(self->child_pidfd1, &st1), 0);

        pidfd = open_by_handle_at(self->pidfd, fh, 0);
        ASSERT_GE(pidfd, 0);

        ASSERT_EQ(fstat(pidfd, &st2), 0);
        ASSERT_TRUE(st1.st_dev == st2.st_dev && st1.st_ino == st2.st_ino);

        ASSERT_EQ(close(pidfd), 0);

        pidfd = open_by_handle_at(self->pidfd, fh, O_CLOEXEC);
        ASSERT_GE(pidfd, 0);

        ASSERT_EQ(fstat(pidfd, &st2), 0);
        ASSERT_TRUE(st1.st_dev == st2.st_dev && st1.st_ino == st2.st_ino);

        ASSERT_EQ(close(pidfd), 0);

        pidfd = open_by_handle_at(self->pidfd, fh, O_NONBLOCK);
        ASSERT_GE(pidfd, 0);

        ASSERT_EQ(fstat(pidfd, &st2), 0);
        ASSERT_TRUE(st1.st_dev == st2.st_dev && st1.st_ino == st2.st_ino);

        ASSERT_EQ(close(pidfd), 0);

        free(fh);
}

/*
 * Test that we can decode a pidfs file handle from a child pid
 * namespace.
 */
TEST_F(file_handle, file_handle_child_pidns)
{
        int mnt_id;
        struct file_handle *fh;
        int pidfd = -EBADF;
        struct stat st1, st2;

        fh = malloc(sizeof(struct file_handle) + MAX_HANDLE_SZ);
        ASSERT_NE(fh, NULL);
        memset(fh, 0, sizeof(struct file_handle) + MAX_HANDLE_SZ);
        fh->handle_bytes = MAX_HANDLE_SZ;

        ASSERT_EQ(name_to_handle_at(self->child_pidfd2, "", fh, &mnt_id, AT_EMPTY_PATH), 0);

        ASSERT_EQ(fstat(self->child_pidfd2, &st1), 0);

        pidfd = open_by_handle_at(self->pidfd, fh, 0);
        ASSERT_GE(pidfd, 0);

        ASSERT_EQ(fstat(pidfd, &st2), 0);
        ASSERT_TRUE(st1.st_dev == st2.st_dev && st1.st_ino == st2.st_ino);

        ASSERT_EQ(close(pidfd), 0);

        pidfd = open_by_handle_at(self->pidfd, fh, O_CLOEXEC);
        ASSERT_GE(pidfd, 0);

        ASSERT_EQ(fstat(pidfd, &st2), 0);
        ASSERT_TRUE(st1.st_dev == st2.st_dev && st1.st_ino == st2.st_ino);

        ASSERT_EQ(close(pidfd), 0);

        pidfd = open_by_handle_at(self->pidfd, fh, O_NONBLOCK);
        ASSERT_GE(pidfd, 0);

        ASSERT_EQ(fstat(pidfd, &st2), 0);
        ASSERT_TRUE(st1.st_dev == st2.st_dev && st1.st_ino == st2.st_ino);

        ASSERT_EQ(close(pidfd), 0);

        free(fh);
}

/*
 * Test that we fail to decode a pidfs file handle from an ancestor
 * child pid namespace.
 */
TEST_F(file_handle, file_handle_foreign_pidns)
{
        int mnt_id;
        struct file_handle *fh;
        pid_t pid;

        fh = malloc(sizeof(struct file_handle) + MAX_HANDLE_SZ);
        ASSERT_NE(fh, NULL);
        memset(fh, 0, sizeof(struct file_handle) + MAX_HANDLE_SZ);
        fh->handle_bytes = MAX_HANDLE_SZ;

        ASSERT_EQ(name_to_handle_at(self->pidfd, "", fh, &mnt_id, AT_EMPTY_PATH), 0);

        ASSERT_EQ(setns(self->child_pidfd2, CLONE_NEWUSER | CLONE_NEWPID), 0);

        pid = fork();
        ASSERT_GE(pid, 0);

        if (pid == 0) {
                int pidfd = open_by_handle_at(self->pidfd, fh, 0);
                if (pidfd >= 0) {
                        TH_LOG("Managed to open pidfd outside of the caller's pid namespace hierarchy");
                        _exit(1);
                }
                _exit(0);
        }

        ASSERT_EQ(wait_for_pid(pid), 0);

        free(fh);
}

/*
 * Test that we can decode a pidfs file handle of a process that has
 * exited but not been reaped.
 */
TEST_F(file_handle, pid_has_exited)
{
        int mnt_id, pidfd, child_pidfd3;
        struct file_handle *fh;
        struct stat st1, st2;

        fh = malloc(sizeof(struct file_handle) + MAX_HANDLE_SZ);
        ASSERT_NE(fh, NULL);
        memset(fh, 0, sizeof(struct file_handle) + MAX_HANDLE_SZ);
        fh->handle_bytes = MAX_HANDLE_SZ;

        ASSERT_EQ(name_to_handle_at(self->child_pidfd3, "", fh, &mnt_id, AT_EMPTY_PATH), 0);

        ASSERT_EQ(fstat(self->child_pidfd3, &st1), 0);

        pidfd = open_by_handle_at(self->pidfd, fh, 0);
        ASSERT_GE(pidfd, 0);

        ASSERT_EQ(fstat(pidfd, &st2), 0);
        ASSERT_TRUE(st1.st_dev == st2.st_dev && st1.st_ino == st2.st_ino);

        ASSERT_EQ(close(pidfd), 0);

        child_pidfd3 = self->child_pidfd3;
        self->child_pidfd3 = -EBADF;
        EXPECT_EQ(sys_pidfd_send_signal(child_pidfd3, SIGKILL, NULL, 0), 0);
        EXPECT_EQ(close(child_pidfd3), 0);
        EXPECT_EQ(sys_waitid(P_PID, self->child_pid3, NULL, WEXITED | WNOWAIT), 0);

        pidfd = open_by_handle_at(self->pidfd, fh, 0);
        ASSERT_GE(pidfd, 0);

        EXPECT_EQ(sys_waitid(P_PID, self->child_pid3, NULL, WEXITED), 0);
}

/*
 * Test that we fail to decode a pidfs file handle of a process that has
 * already been reaped.
 */
TEST_F(file_handle, pid_has_been_reaped)
{
        int mnt_id, pidfd, child_pidfd3;
        struct file_handle *fh;
        struct stat st1, st2;

        fh = malloc(sizeof(struct file_handle) + MAX_HANDLE_SZ);
        ASSERT_NE(fh, NULL);
        memset(fh, 0, sizeof(struct file_handle) + MAX_HANDLE_SZ);
        fh->handle_bytes = MAX_HANDLE_SZ;

        ASSERT_EQ(name_to_handle_at(self->child_pidfd3, "", fh, &mnt_id, AT_EMPTY_PATH), 0);

        ASSERT_EQ(fstat(self->child_pidfd3, &st1), 0);

        pidfd = open_by_handle_at(self->pidfd, fh, 0);
        ASSERT_GE(pidfd, 0);

        ASSERT_EQ(fstat(pidfd, &st2), 0);
        ASSERT_TRUE(st1.st_dev == st2.st_dev && st1.st_ino == st2.st_ino);

        ASSERT_EQ(close(pidfd), 0);

        child_pidfd3 = self->child_pidfd3;
        self->child_pidfd3 = -EBADF;
        EXPECT_EQ(sys_pidfd_send_signal(child_pidfd3, SIGKILL, NULL, 0), 0);
        EXPECT_EQ(close(child_pidfd3), 0);
        EXPECT_EQ(sys_waitid(P_PID, self->child_pid3, NULL, WEXITED), 0);

        pidfd = open_by_handle_at(self->pidfd, fh, 0);
        ASSERT_LT(pidfd, 0);
}

/*
 * Test valid flags to open a pidfd file handle. Note, that
 * PIDFD_NONBLOCK is defined as O_NONBLOCK and O_NONBLOCK is an alias to
 * O_NDELAY. Also note that PIDFD_THREAD is an alias for O_EXCL.
 */
TEST_F(file_handle, open_by_handle_at_valid_flags)
{
        int mnt_id;
        struct file_handle *fh;
        int pidfd = -EBADF;
        struct stat st1, st2;

        fh = malloc(sizeof(struct file_handle) + MAX_HANDLE_SZ);
        ASSERT_NE(fh, NULL);
        memset(fh, 0, sizeof(struct file_handle) + MAX_HANDLE_SZ);
        fh->handle_bytes = MAX_HANDLE_SZ;

        ASSERT_EQ(name_to_handle_at(self->child_pidfd2, "", fh, &mnt_id, AT_EMPTY_PATH), 0);

        ASSERT_EQ(fstat(self->child_pidfd2, &st1), 0);

        pidfd = open_by_handle_at(self->pidfd, fh,
                                  O_RDONLY |
                                  O_WRONLY |
                                  O_RDWR |
                                  O_NONBLOCK |
                                  O_NDELAY |
                                  O_CLOEXEC |
                                  O_EXCL);
        ASSERT_GE(pidfd, 0);

        ASSERT_EQ(fstat(pidfd, &st2), 0);
        ASSERT_TRUE(st1.st_dev == st2.st_dev && st1.st_ino == st2.st_ino);

        ASSERT_EQ(close(pidfd), 0);
}

/*
 * Test that invalid flags passed to open a pidfd file handle are
 * rejected.
 */
TEST_F(file_handle, open_by_handle_at_invalid_flags)
{
        int mnt_id;
        struct file_handle *fh;
        int pidfd = -EBADF;
        static const struct invalid_pidfs_file_handle_flags {
                int oflag;
                const char *oflag_name;
        }  invalid_pidfs_file_handle_flags[] = {
                { FASYNC,       "FASYNC"        },
                { O_CREAT,      "O_CREAT"       },
                { O_NOCTTY,     "O_NOCTTY"      },
                { O_CREAT,      "O_CREAT"       },
                { O_TRUNC,      "O_TRUNC"       },
                { O_APPEND,     "O_APPEND"      },
                { O_SYNC,       "O_SYNC"        },
                { O_DSYNC,      "O_DSYNC"       },
                { O_DIRECT,     "O_DIRECT"      },
                { O_DIRECTORY,  "O_DIRECTORY"   },
                { O_NOFOLLOW,   "O_NOFOLLOW"    },
                { O_NOATIME,    "O_NOATIME"     },
                { O_PATH,       "O_PATH"        },
                { O_TMPFILE,    "O_TMPFILE"     },
                /*
                 * O_LARGEFILE is added implicitly by
                 * open_by_handle_at() so pidfs simply masks it off.
                 */
        };

        fh = malloc(sizeof(struct file_handle) + MAX_HANDLE_SZ);
        ASSERT_NE(fh, NULL);
        memset(fh, 0, sizeof(struct file_handle) + MAX_HANDLE_SZ);
        fh->handle_bytes = MAX_HANDLE_SZ;

        ASSERT_EQ(name_to_handle_at(self->child_pidfd2, "", fh, &mnt_id, AT_EMPTY_PATH), 0);

        for (int i = 0; i < ARRAY_SIZE(invalid_pidfs_file_handle_flags); i++) {
                pidfd = open_by_handle_at(self->pidfd, fh, invalid_pidfs_file_handle_flags[i].oflag);
                ASSERT_LT(pidfd, 0) {
                        TH_LOG("open_by_handle_at() succeeded with invalid flags: %s", invalid_pidfs_file_handle_flags[i].oflag_name);
                }
        }
}

/* Test that lookup fails. */
TEST_F(file_handle, lookup_must_fail)
{
        int mnt_id;
        struct file_handle *fh;

        fh = malloc(sizeof(struct file_handle) + MAX_HANDLE_SZ);
        ASSERT_NE(fh, NULL);
        memset(fh, 0, sizeof(struct file_handle) + MAX_HANDLE_SZ);
        fh->handle_bytes = MAX_HANDLE_SZ;

        ASSERT_NE(name_to_handle_at(self->child_pidfd2, "lookup-is-not-possible-with-pidfs", fh, &mnt_id, AT_EMPTY_PATH), 0);
        ASSERT_EQ(errno, ENOTDIR);
        ASSERT_NE(name_to_handle_at(self->child_pidfd2, "lookup-is-not-possible-with-pidfs", fh, &mnt_id, 0), 0);
        ASSERT_EQ(errno, ENOTDIR);
}

#ifndef AT_HANDLE_CONNECTABLE
#define AT_HANDLE_CONNECTABLE 0x002
#endif

/*
 * Test that AT_HANDLE_CONNECTABLE is rejected. Connectable file handles
 * don't make sense for pidfs. Note that currently AT_HANDLE_CONNECTABLE
 * is rejected because it is incompatible with AT_EMPTY_PATH which is
 * required with pidfds as we don't support lookup.
 */
TEST_F(file_handle, invalid_name_to_handle_at_flags)
{
        int mnt_id;
        struct file_handle *fh;

        fh = malloc(sizeof(struct file_handle) + MAX_HANDLE_SZ);
        ASSERT_NE(fh, NULL);
        memset(fh, 0, sizeof(struct file_handle) + MAX_HANDLE_SZ);
        fh->handle_bytes = MAX_HANDLE_SZ;

        ASSERT_NE(name_to_handle_at(self->child_pidfd2, "", fh, &mnt_id, AT_EMPTY_PATH | AT_HANDLE_CONNECTABLE), 0);
}

#ifndef AT_HANDLE_FID
#define AT_HANDLE_FID 0x200
#endif

/*
 * Test that a request with AT_HANDLE_FID always leads to decodable file
 * handle as pidfs always provides export operations.
 */
TEST_F(file_handle, valid_name_to_handle_at_flags)
{
        int mnt_id, pidfd;
        struct file_handle *fh;
        struct stat st1, st2;

        fh = malloc(sizeof(struct file_handle) + MAX_HANDLE_SZ);
        ASSERT_NE(fh, NULL);
        memset(fh, 0, sizeof(struct file_handle) + MAX_HANDLE_SZ);
        fh->handle_bytes = MAX_HANDLE_SZ;

        ASSERT_EQ(name_to_handle_at(self->child_pidfd2, "", fh, &mnt_id, AT_EMPTY_PATH | AT_HANDLE_FID), 0);

        ASSERT_EQ(fstat(self->child_pidfd2, &st1), 0);

        pidfd = open_by_handle_at(self->pidfd, fh, 0);
        ASSERT_GE(pidfd, 0);

        ASSERT_EQ(fstat(pidfd, &st2), 0);
        ASSERT_TRUE(st1.st_dev == st2.st_dev && st1.st_ino == st2.st_ino);

        ASSERT_EQ(close(pidfd), 0);
}

/*
 * That we decode a file handle without having to pass a pidfd.
 */
TEST_F(file_handle, decode_purely_based_on_file_handle)
{
        int mnt_id;
        struct file_handle *fh;
        int pidfd = -EBADF;
        struct stat st1, st2;

        fh = malloc(sizeof(struct file_handle) + MAX_HANDLE_SZ);
        ASSERT_NE(fh, NULL);
        memset(fh, 0, sizeof(struct file_handle) + MAX_HANDLE_SZ);
        fh->handle_bytes = MAX_HANDLE_SZ;

        ASSERT_EQ(name_to_handle_at(self->child_pidfd1, "", fh, &mnt_id, AT_EMPTY_PATH), 0);

        ASSERT_EQ(fstat(self->child_pidfd1, &st1), 0);

        pidfd = open_by_handle_at(FD_PIDFS_ROOT, fh, 0);
        ASSERT_GE(pidfd, 0);

        ASSERT_EQ(fstat(pidfd, &st2), 0);
        ASSERT_TRUE(st1.st_dev == st2.st_dev && st1.st_ino == st2.st_ino);

        ASSERT_EQ(close(pidfd), 0);

        pidfd = open_by_handle_at(FD_PIDFS_ROOT, fh, O_CLOEXEC);
        ASSERT_GE(pidfd, 0);

        ASSERT_EQ(fstat(pidfd, &st2), 0);
        ASSERT_TRUE(st1.st_dev == st2.st_dev && st1.st_ino == st2.st_ino);

        ASSERT_EQ(close(pidfd), 0);

        pidfd = open_by_handle_at(FD_PIDFS_ROOT, fh, O_NONBLOCK);
        ASSERT_GE(pidfd, 0);

        ASSERT_EQ(fstat(pidfd, &st2), 0);
        ASSERT_TRUE(st1.st_dev == st2.st_dev && st1.st_ino == st2.st_ino);

        ASSERT_EQ(close(pidfd), 0);

        pidfd = open_by_handle_at(self->pidfd, fh, 0);
        ASSERT_GE(pidfd, 0);

        ASSERT_EQ(fstat(pidfd, &st2), 0);
        ASSERT_TRUE(st1.st_dev == st2.st_dev && st1.st_ino == st2.st_ino);

        ASSERT_EQ(close(pidfd), 0);

        pidfd = open_by_handle_at(-EBADF, fh, 0);
        ASSERT_LT(pidfd, 0);

        pidfd = open_by_handle_at(AT_FDCWD, fh, 0);
        ASSERT_LT(pidfd, 0);

        free(fh);
}

TEST_HARNESS_MAIN