/*

 * Copyright 2024-2025 The OpenSSL Project Authors. All Rights Reserved.

 *

 * Licensed under the Apache License 2.0 (the "License").  You may not use

 * this file except in compliance with the License.  You can obtain a copy

 * in the file LICENSE in the source distribution or at

 * https://www.openssl.org/source/license.html

 */

#include "internal/sockets.h"

#include <openssl/bio.h>

#include <openssl/err.h>

#include "internal/thread_once.h"

#include "internal/rio_notifier.h"

#if !defined(OPENSSL_SYS_WINDOWS) || RIO_NOTIFIER_METHOD == RIO_NOTIFIER_METHOD_SOCKETPAIR

/*

 * Sets a socket as close-on-exec, except that this is a no-op if we are certain

 * we do not need to do this or the OS does not support the concept.

 */

static int set_cloexec(int fd)

{

#if !defined(SOCK_CLOEXEC) && defined(FD_CLOEXEC)

    return fcntl(fd, F_SETFD, FD_CLOEXEC) >= 0;

#else

    return 1;

#endif

}

#endif

#if defined(OPENSSL_SYS_WINDOWS)

static CRYPTO_ONCE ensure_wsa_startup_once = CRYPTO_ONCE_STATIC_INIT;

static CRYPTO_RWLOCK *wsa_lock;

static int wsa_started;

static int wsa_ref;

static void ossl_wsa_cleanup(void)

{

    if (wsa_started) {

        wsa_started = 0;

        WSACleanup();

    }

    CRYPTO_THREAD_lock_free(wsa_lock);

    wsa_lock = NULL;

}

DEFINE_RUN_ONCE_STATIC(do_wsa_startup)

{

    WORD versionreq = 0x0202; /* Version 2.2 */

    WSADATA wsadata;

    wsa_lock = CRYPTO_THREAD_lock_new();

    if (wsa_lock == NULL)

        return 0;

    if (WSAStartup(versionreq, &wsadata) != 0) {

        CRYPTO_THREAD_lock_free(wsa_lock);

        wsa_lock = NULL;

        return 0;

    }

    wsa_started = 1;

    return 1;

}

static ossl_inline int ensure_wsa_startup(void)

{

    int rv, unused;

    rv = RUN_ONCE(&ensure_wsa_startup_once, do_wsa_startup);

    if (rv != 0)

        CRYPTO_atomic_add(&wsa_ref, 1, &unused, wsa_lock);

    return rv;

}

static void wsa_done(void)

{

    int ref;

    if (wsa_lock != NULL) {

        CRYPTO_atomic_add(&wsa_ref, -1, &ref, wsa_lock);

        if (ref == 0) {

            ossl_wsa_cleanup();

            ensure_wsa_startup_once = CRYPTO_ONCE_STATIC_INIT;

            wsa_lock = NULL;

        }

    }

}

#endif

#if RIO_NOTIFIER_METHOD == RIO_NOTIFIER_METHOD_SOCKET

/* Create a close-on-exec socket. */

static int create_socket(int domain, int socktype, int protocol)

{

    int fd;

#if defined(OPENSSL_SYS_WINDOWS)

    static const int on = 1;

    /*

     * Use WSASocketA to create a socket which is immediately marked as

     * non-inheritable, avoiding race conditions if another thread is about to

     * call CreateProcess.

     * NOTE: windows xp (0x501) doesn't support the non-inheritance flag here

     * but preventing inheritance isn't mandatory, just a safety precaution

     * so we can get away with not including it for older platforms

     */

#ifdef WSA_FLAG_NO_HANDLE_INHERIT

    fd = (int)WSASocketA(domain, socktype, protocol, NULL, 0,

        WSA_FLAG_NO_HANDLE_INHERIT);

    /*

     * Its also possible that someone is building a binary on a newer windows

     * SDK, but running it on a runtime that doesn't support inheritance

     * suppression.  In that case the above will return INVALID_SOCKET, and

     * our response for those older platforms is to try the call again

     * without the flag

     */

    if (fd == INVALID_SOCKET)

        fd = (int)WSASocketA(domain, socktype, protocol, NULL, 0, 0);

#else

    fd = (int)WSASocketA(domain, socktype, protocol, NULL, 0, 0);

#endif

    if (fd == INVALID_SOCKET) {

        int err = get_last_socket_error();

        ERR_raise_data(ERR_LIB_SYS, err,

            "calling WSASocketA() = %d", err);

        return INVALID_SOCKET;

    }

    /* Prevent interference with the socket from other processes on Windows. */

    if (setsockopt(fd, SOL_SOCKET, SO_EXCLUSIVEADDRUSE, (void *)&on, sizeof(on)) < 0) {

        ERR_raise_data(ERR_LIB_SYS, get_last_socket_error(),

            "calling setsockopt()");

        BIO_closesocket(fd);

        return INVALID_SOCKET;

    }

#else

#if defined(SOCK_CLOEXEC)

    socktype |= SOCK_CLOEXEC;

#endif

    fd = BIO_socket(domain, socktype, protocol, 0);

    if (fd == INVALID_SOCKET) {

        ERR_raise_data(ERR_LIB_SYS, get_last_sys_error(),

            "calling BIO_socket()");

        return INVALID_SOCKET;

    }

    /*

     * Make socket close-on-exec unless this was already done above at socket

     * creation time.

     */

    if (!set_cloexec(fd)) {

        ERR_raise_data(ERR_LIB_SYS, get_last_sys_error(),

            "calling set_cloexec()");

        BIO_closesocket(fd);

        return INVALID_SOCKET;

    }

#endif

    return fd;

}

/*

 * The SOCKET notifier method manually creates a connected TCP socket pair by

 * temporarily creating a TCP listener on a random port and connecting back to

 * it.

 *

 * Win32 does not support socketpair(2), and Win32 pipes are not compatible with

 * Winsock select(2). This means our only means of making select(2) wakeable is

 * to artificially create a loopback TCP connection and send bytes to it.

 */

int ossl_rio_notifier_init(RIO_NOTIFIER *nfy)

{

    int rc, lfd = -1, rfd = -1, wfd = -1;

    struct sockaddr_in sa = { 0 }, accept_sa;

    socklen_t sa_len = sizeof(sa), accept_sa_len = sizeof(accept_sa);

#if defined(OPENSSL_SYS_WINDOWS)

    if (!ensure_wsa_startup()) {

        ERR_raise_data(ERR_LIB_SSL, ERR_R_INTERNAL_ERROR,

            "Cannot start Windows sockets");

        wsa_done();

        return 0;

    }

#endif

    /* Create a close-on-exec socket. */

    lfd = create_socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);

    if (lfd == INVALID_SOCKET) {

        ERR_raise_data(ERR_LIB_SYS, get_last_sys_error(),

            "calling create_socket()");

        return 0;

    }

    /* Bind the socket to a random loopback port. */

    sa.sin_family = AF_INET;

    sa.sin_addr.s_addr = htonl(INADDR_LOOPBACK);

    rc = bind(lfd, (const struct sockaddr *)&sa, sizeof(sa));

    if (rc < 0) {

        ERR_raise_data(ERR_LIB_SYS, get_last_sys_error(),

            "calling bind()");

        goto err;

    }

    /* Determine what random port was allocated. */

    rc = getsockname(lfd, (struct sockaddr *)&sa, &sa_len);

    if (rc < 0) {

        ERR_raise_data(ERR_LIB_SYS, get_last_sys_error(),

            "calling getsockname()");

        goto err;

    }

    /* Start listening. */

    rc = listen(lfd, 1);

    if (rc < 0) {

        ERR_raise_data(ERR_LIB_SYS, get_last_sys_error(),

            "calling listen()");

        goto err;

    }

    /* Create another socket to connect to the listener. */

    wfd = create_socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);

    if (wfd == INVALID_SOCKET) {

        ERR_raise_data(ERR_LIB_SYS, get_last_sys_error(),

            "calling create_socket()");

        goto err;

    }

    /*

     * Disable Nagle's algorithm on the writer so that wakeups happen

     * immediately.

     */

    if (!BIO_set_tcp_ndelay(wfd, 1)) {

        ERR_raise_data(ERR_LIB_SYS, get_last_sys_error(),

            "calling BIO_set_tcp_ndelay()");

        goto err;

    }

    /*

     * Connect the writer to the listener.

     */

    rc = connect(wfd, (struct sockaddr *)&sa, sizeof(sa));

    if (rc < 0) {

        ERR_raise_data(ERR_LIB_SYS, get_last_sys_error(),

            "calling connect()");

        goto err;

    }

    /*

     * The connection accepted from the listener is the read side.

     */

    rfd = accept(lfd, (struct sockaddr *)&accept_sa, &accept_sa_len);

    if (rfd == INVALID_SOCKET) {

        ERR_raise_data(ERR_LIB_SYS, get_last_sys_error(),

            "calling accept()");

        goto err;

    }

    rc = getsockname(wfd, (struct sockaddr *)&sa, &sa_len);

    if (rc < 0) {

        ERR_raise_data(ERR_LIB_SYS, get_last_sys_error(),

            "calling getsockname()");

        goto err;

    }

    /* Close the listener, which we don't need anymore. */

    BIO_closesocket(lfd);

    lfd = -1;

    /*

     * Sanity check - ensure someone else didn't connect to our listener during

     * the brief window of possibility above.

     */

    if (accept_sa.sin_family != AF_INET || accept_sa.sin_port != sa.sin_port) {

        ERR_raise_data(ERR_LIB_SSL, ERR_R_INTERNAL_ERROR,

            "connected address differs from accepted address");

        goto err;

    }

    /* Make both sides of the connection non-blocking. */

    if (!BIO_socket_nbio(rfd, 1)) {

        ERR_raise_data(ERR_LIB_SYS, get_last_sys_error(),

            "calling BIO_socket_nbio()");

        goto err;

    }

    if (!BIO_socket_nbio(wfd, 1)) {

        ERR_raise_data(ERR_LIB_SYS, get_last_sys_error(),

            "calling BIO_socket_nbio()");

        goto err;

    }

    nfy->rfd = rfd;

    nfy->wfd = wfd;

    return 1;

err:

    if (lfd != INVALID_SOCKET)

        BIO_closesocket(lfd);

    if (wfd != INVALID_SOCKET)

        BIO_closesocket(wfd);

    if (rfd != INVALID_SOCKET)

        BIO_closesocket(rfd);

    return 0;

}

#elif RIO_NOTIFIER_METHOD == RIO_NOTIFIER_METHOD_SOCKETPAIR

int ossl_rio_notifier_init(RIO_NOTIFIER *nfy)

{

    int fds[2], domain = AF_INET, type = SOCK_STREAM;

#if defined(SOCK_CLOEXEC)

    type |= SOCK_CLOEXEC;

#endif

#if defined(SOCK_NONBLOCK)

    type |= SOCK_NONBLOCK;

#endif

#if defined(OPENSSL_SYS_UNIX) && defined(AF_UNIX)

    domain = AF_UNIX;

#endif

    if (socketpair(domain, type, 0, fds) < 0) {

        ERR_raise_data(ERR_LIB_SYS, get_last_sys_error(),

            "calling socketpair()");

        return 0;

    }

    if (!set_cloexec(fds[0]) || !set_cloexec(fds[1])) {

        ERR_raise_data(ERR_LIB_SYS, get_last_sys_error(),

            "calling set_cloexec()");

        goto err;

    }

#if !defined(SOCK_NONBLOCK)

    if (!BIO_socket_nbio(fds[0], 1) || !BIO_socket_nbio(fds[1], 1)) {

        ERR_raise_data(ERR_LIB_SYS, get_last_sys_error(),

            "calling BIO_socket_nbio()");

        goto err;

    }

#endif

    if (domain == AF_INET && !BIO_set_tcp_ndelay(fds[1], 1)) {

        ERR_raise_data(ERR_LIB_SYS, get_last_sys_error(),

            "calling BIO_set_tcp_ndelay()");

        goto err;

    }

    nfy->rfd = fds[0];

    nfy->wfd = fds[1];

    return 1;

err:

    BIO_closesocket(fds[1]);

    BIO_closesocket(fds[0]);

    return 0;

}

#endif

void ossl_rio_notifier_cleanup(RIO_NOTIFIER *nfy)

{

    if (nfy->rfd < 0)

        return;

    BIO_closesocket(nfy->wfd);

    BIO_closesocket(nfy->rfd);

    nfy->rfd = nfy->wfd = -1;

#if defined(OPENSSL_SYS_WINDOWS)

    wsa_done();

#endif

}

int ossl_rio_notifier_signal(RIO_NOTIFIER *nfy)

{

    static const unsigned char ch = 0;

    ossl_ssize_t wr;

    do

        /*

         * Note: If wr returns 0 the buffer is already full so we don't need to

         * do anything.

         */

        wr = writesocket(nfy->wfd, (void *)&ch, sizeof(ch));

    while (wr < 0 && get_last_socket_error_is_eintr());

    return 1;

}

int ossl_rio_notifier_unsignal(RIO_NOTIFIER *nfy)

{

    unsigned char buf[16];

    ossl_ssize_t rd;

    /*

     * signal() might have been called multiple times. Drain the buffer until

     * it's empty.

     */

    do

        rd = readsocket(nfy->rfd, (void *)buf, sizeof(buf));

    while (rd == sizeof(buf)

        || (rd < 0 && get_last_socket_error_is_eintr()));

    if (rd < 0 && !BIO_fd_non_fatal_error(get_last_socket_error()))

        return 0;

    return 1;

}