/*

 * Copyright 1995-2025 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 <stdio.h>

#include <errno.h>

#include "bio_local.h"

#if defined(OPENSSL_NO_POSIX_IO)

/*

 * Dummy placeholder for BIO_s_fd...

 */

BIO *BIO_new_fd(int fd, int close_flag)

{

    return NULL;

}

int BIO_fd_non_fatal_error(int err)

{

    return 0;

}

int BIO_fd_should_retry(int i)

{

    return 0;

}

const BIO_METHOD *BIO_s_fd(void)

{

    return NULL;

}

#else

/*

 * As for unconditional usage of "UPLINK" interface in this module.

 * Trouble is that unlike Unix file descriptors [which are indexes

 * in kernel-side per-process table], corresponding descriptors on

 * platforms which require "UPLINK" interface seem to be indexes

 * in a user-land, non-global table. Well, in fact they are indexes

 * in stdio _iob[], and recall that _iob[] was the very reason why

 * "UPLINK" interface was introduced in first place. But one way on

 * another. Neither libcrypto or libssl use this BIO meaning that

 * file descriptors can only be provided by application. Therefore

 * "UPLINK" calls are due...

 */

static int fd_write(BIO *h, const char *buf, int num);

static int fd_read(BIO *h, char *buf, int size);

static int fd_puts(BIO *h, const char *str);

static int fd_gets(BIO *h, char *buf, int size);

static long fd_ctrl(BIO *h, int cmd, long arg1, void *arg2);

static int fd_new(BIO *h);

static int fd_free(BIO *data);

int BIO_fd_should_retry(int s);

static const BIO_METHOD methods_fdp = {

    BIO_TYPE_FD,

    "file descriptor",

    bwrite_conv,

    fd_write,

    bread_conv,

    fd_read,

    fd_puts,

    fd_gets,

    fd_ctrl,

    fd_new,

    fd_free,

    NULL,                       /* fd_callback_ctrl */

};

const BIO_METHOD *BIO_s_fd(void)

{

    return &methods_fdp;

}

BIO *BIO_new_fd(int fd, int close_flag)

{

    BIO *ret;

    ret = BIO_new(BIO_s_fd());

    if (ret == NULL)

        return NULL;

    BIO_set_fd(ret, fd, close_flag);

    return ret;

}

static int fd_new(BIO *bi)

{

    bi->init = 0;

    bi->num = -1;

    bi->ptr = NULL;

    bi->flags = BIO_FLAGS_UPLINK_INTERNAL; /* essentially redundant */

    return 1;

}

static int fd_free(BIO *a)

{

    if (a == NULL)

        return 0;

    if (a->shutdown) {

        if (a->init) {

            UP_close(a->num);

        }

        a->init = 0;

        a->flags = BIO_FLAGS_UPLINK_INTERNAL;

    }

    return 1;

}

static int fd_read(BIO *b, char *out, int outl)

{

    int ret = 0;

    if (out != NULL) {

        clear_sys_error();

        ret = (int)UP_read(b->num, out, outl);

        BIO_clear_retry_flags(b);

        if (ret <= 0) {

            if (BIO_fd_should_retry(ret))

                BIO_set_retry_read(b);

            else if (ret == 0)

                b->flags |= BIO_FLAGS_IN_EOF;

        }

    }

    return ret;

}

static int fd_write(BIO *b, const char *in, int inl)

{

    int ret;

    clear_sys_error();

    ret = (int)UP_write(b->num, in, inl);

    BIO_clear_retry_flags(b);

    if (ret <= 0) {

        if (BIO_fd_should_retry(ret))

            BIO_set_retry_write(b);

    }

    return ret;

}

static long fd_ctrl(BIO *b, int cmd, long num, void *ptr)

{

    long ret = 1;

    int *ip;

    switch (cmd) {

    case BIO_CTRL_RESET:

        num = 0;

        /* fall through */

    case BIO_C_FILE_SEEK:

        ret = (long)UP_lseek(b->num, num, 0);

        break;

    case BIO_C_FILE_TELL:

    case BIO_CTRL_INFO:

        ret = (long)UP_lseek(b->num, 0, 1);

        break;

    case BIO_C_SET_FD:

        fd_free(b);

        b->num = *((int *)ptr);

        b->shutdown = (int)num;

        b->init = 1;

        break;

    case BIO_C_GET_FD:

        if (b->init) {

            ip = (int *)ptr;

            if (ip != NULL)

                *ip = b->num;

            ret = b->num;

        } else

            ret = -1;

        break;

    case BIO_CTRL_GET_CLOSE:

        ret = b->shutdown;

        break;

    case BIO_CTRL_SET_CLOSE:

        b->shutdown = (int)num;

        break;

    case BIO_CTRL_PENDING:

    case BIO_CTRL_WPENDING:

        ret = 0;

        break;

    case BIO_CTRL_DUP:

    case BIO_CTRL_FLUSH:

        ret = 1;

        break;

    case BIO_CTRL_EOF:

        ret = (b->flags & BIO_FLAGS_IN_EOF) != 0;

        break;

    default:

        ret = 0;

        break;

    }

    return ret;

}

static int fd_puts(BIO *bp, const char *str)

{

    int ret;

    size_t n = strlen(str);

    if (n > INT_MAX)

        return -1;

    ret = fd_write(bp, str, (int)n);

    return ret;

}

static int fd_gets(BIO *bp, char *buf, int size)

{

    int ret = 0;

    char *ptr = buf;

    char *end = buf + size - 1;

    while (ptr < end && fd_read(bp, ptr, 1) > 0) {

        if (*ptr++ == '\n')

           break;

    }

    ptr[0] = '\0';

    if (buf[0] != '\0')

        ret = (int)strlen(buf);

    return ret;

}

int BIO_fd_should_retry(int i)

{

    int err;

    if ((i == 0) || (i == -1)) {

        err = get_last_sys_error();

        return BIO_fd_non_fatal_error(err);

    }

    return 0;

}

int BIO_fd_non_fatal_error(int err)

{

    switch (err) {

# ifdef EWOULDBLOCK

#  ifdef WSAEWOULDBLOCK

#   if WSAEWOULDBLOCK != EWOULDBLOCK

    case EWOULDBLOCK:

#   endif

#  else

    case EWOULDBLOCK:

#  endif

# endif

# if defined(ENOTCONN)

    case ENOTCONN:

# endif

# ifdef EINTR

    case EINTR:

# endif

# ifdef EAGAIN

#  if EWOULDBLOCK != EAGAIN

    case EAGAIN:

#  endif

# endif

# ifdef EPROTO

    case EPROTO:

# endif

# ifdef EINPROGRESS

    case EINPROGRESS:

# endif

# ifdef EALREADY

    case EALREADY:

# endif

        return 1;

    default:

        break;

    }

    return 0;

}

#endif