// Copyright 1995-2016 The OpenSSL Project Authors. All Rights Reserved.

//

// Licensed under the Apache License, Version 2.0 (the "License");

// you may not use this file except in compliance with the License.

// You may obtain a copy of the License at

//

//     https://www.apache.org/licenses/LICENSE-2.0

//

// Unless required by applicable law or agreed to in writing, software

// distributed under the License is distributed on an "AS IS" BASIS,

// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

// See the License for the specific language governing permissions and

// limitations under the License.

#if defined(__linux) || defined(__sun) || defined(__hpux)

// Following definition aliases fopen to fopen64 on above mentioned

// platforms. This makes it possible to open and sequentially access

// files larger than 2GB from 32-bit application. It does not allow to

// traverse them beyond 2GB with fseek/ftell, but on the other hand *no*

// 32-bit platform permits that, not with fseek/ftell. Not to mention

// that breaking 2GB limit for seeking would require surgery to *our*

// API. But sequential access suffices for practical cases when you

// can run into large files, such as fingerprinting, so we can let API

// alone. For reference, the list of 32-bit platforms which allow for

// sequential access of large files without extra "magic" comprise *BSD,

// Darwin, IRIX...

#ifndef _FILE_OFFSET_BITS

#define _FILE_OFFSET_BITS 64

#endif

#endif

#include <openssl/bio.h>

#include <assert.h>

#include <errno.h>

#include <stdio.h>

#include <string.h>

#include <openssl/err.h>

#include <openssl/mem.h>

#include "../internal.h"

#include "internal.h"

#if defined(OPENSSL_WINDOWS)

#include <fcntl.h>

#include <io.h>

#endif

#define BIO_FP_READ 0x02

#define BIO_FP_WRITE 0x04

#define BIO_FP_APPEND 0x08

#if !defined(OPENSSL_NO_FILESYSTEM)

#define fopen_if_available fopen

#else

static FILE *fopen_if_available(const char *path, const char *mode) {

  errno = ENOENT;

  return NULL;

}

#endif

BIO *BIO_new_file(const char *filename, const char *mode) {

  BIO *ret;

  FILE *file;

  file = fopen_if_available(filename, mode);

  if (file == NULL) {

    OPENSSL_PUT_SYSTEM_ERROR();

    ERR_add_error_data(5, "fopen('", filename, "','", mode, "')");

    if (errno == ENOENT) {

      OPENSSL_PUT_ERROR(BIO, BIO_R_NO_SUCH_FILE);

    } else {

      OPENSSL_PUT_ERROR(BIO, BIO_R_SYS_LIB);

    }

    return NULL;

  }

  ret = BIO_new_fp(file, BIO_CLOSE);

  if (ret == NULL) {

    fclose(file);

    return NULL;

  }

  return ret;

}

BIO *BIO_new_fp(FILE *stream, int flags) {

  BIO *ret = BIO_new(BIO_s_file());

  if (ret == NULL) {

    return NULL;

  }

  BIO_set_fp(ret, stream, flags);

  return ret;

}

static int file_free(BIO *bio) {

  if (!bio->shutdown) {

    return 1;

  }

  if (bio->init && bio->ptr != NULL) {

    fclose(reinterpret_cast<FILE *>(bio->ptr));

    bio->ptr = NULL;

  }

  bio->init = 0;

  return 1;

}

static int file_read(BIO *b, char *out, int outl) {

  if (!b->init) {

    return 0;

  }

  size_t ret = fread(out, 1, outl, (FILE *)b->ptr);

  if (ret == 0 && ferror((FILE *)b->ptr)) {

    OPENSSL_PUT_SYSTEM_ERROR();

    OPENSSL_PUT_ERROR(BIO, ERR_R_SYS_LIB);

    return -1;

  }

  // fread reads at most |outl| bytes, so |ret| fits in an int.

  return (int)ret;

}

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

  if (!b->init) {

    return 0;

  }

  int ret = (int)fwrite(in, inl, 1, (FILE *)b->ptr);

  if (ret > 0) {

    ret = inl;

  }

  return ret;

}

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

  FILE *fp = static_cast<FILE *>(b->ptr);

  switch (cmd) {

    case BIO_CTRL_RESET:

      num = 0;

      [[fallthrough]];

    case BIO_C_FILE_SEEK:

      return fseek(fp, num, 0);

    case BIO_CTRL_EOF:

      return feof(fp);

    case BIO_C_FILE_TELL:

    case BIO_CTRL_INFO:

      return ftell(fp);

    case BIO_C_SET_FILE_PTR:

      file_free(b);

      static_assert((BIO_CLOSE & BIO_FP_TEXT) == 0,

                    "BIO_CLOSE and BIO_FP_TEXT must not collide");

#if defined(OPENSSL_WINDOWS)

      // If |BIO_FP_TEXT| is not set, OpenSSL will switch the file to binary

      // mode. BoringSSL intentionally diverges here because it means code

      // tested under POSIX will inadvertently change the state of |FILE|

      // objects when wrapping them in a |BIO|.

      if (num & BIO_FP_TEXT) {

        _setmode(_fileno(reinterpret_cast<FILE *>(ptr)), _O_TEXT);

      }

#endif

      b->shutdown = static_cast<int>(num) & BIO_CLOSE;

      b->ptr = ptr;

      b->init = 1;

      return 1;

    case BIO_C_SET_FILENAME:

      file_free(b);

      b->shutdown = static_cast<int>(num) & BIO_CLOSE;

      const char *mode;

      if (num & BIO_FP_APPEND) {

        if (num & BIO_FP_READ) {

          mode = "ab+";

        } else {

          mode = "ab";

        }

      } else if ((num & BIO_FP_READ) && (num & BIO_FP_WRITE)) {

        mode = "rb+";

      } else if (num & BIO_FP_WRITE) {

        mode = "wb";

      } else if (num & BIO_FP_READ) {

        mode = "rb";

      } else {

        OPENSSL_PUT_ERROR(BIO, BIO_R_BAD_FOPEN_MODE);

        return 0;

      }

      fp = fopen_if_available(reinterpret_cast<const char *>(ptr), mode);

      if (fp == nullptr) {

        OPENSSL_PUT_SYSTEM_ERROR();

        ERR_add_error_data(5, "fopen('", ptr, "','", mode, "')");

        OPENSSL_PUT_ERROR(BIO, ERR_R_SYS_LIB);

        return 0;

      }

      b->ptr = fp;

      b->init = 1;

      return 1;

    case BIO_C_GET_FILE_PTR:

      // the ptr parameter is actually a FILE ** in this case.

      if (ptr != nullptr) {

        FILE **out = static_cast<FILE **>(ptr);

        *out = fp;

      }

      return 1;

    case BIO_CTRL_GET_CLOSE:

      return b->shutdown;

    case BIO_CTRL_SET_CLOSE:

      b->shutdown = static_cast<int>(num);

      return 1;

    case BIO_CTRL_FLUSH:

      return fflush(fp) == 0;

    default:

      return 0;

  }

}

static int file_gets(BIO *bp, char *buf, int size) {

  if (size == 0) {

    return 0;

  }

  if (!fgets(buf, size, (FILE *)bp->ptr)) {

    buf[0] = 0;

    // TODO(davidben): This doesn't distinguish error and EOF. This should check

    // |ferror| as in |file_read|.

    return 0;

  }

  return (int)strlen(buf);

}

static const BIO_METHOD methods_filep = {

    BIO_TYPE_FILE,      "FILE pointer", file_write,

    file_read,          file_gets,      file_ctrl,

    /*create=*/nullptr, file_free,      /*callback_ctrl=*/nullptr,

};

const BIO_METHOD *BIO_s_file(void) { return &methods_filep; }

int BIO_get_fp(BIO *bio, FILE **out_file) {

  return (int)BIO_ctrl(bio, BIO_C_GET_FILE_PTR, 0, (char *)out_file);

}

int BIO_set_fp(BIO *bio, FILE *file, int flags) {

  return (int)BIO_ctrl(bio, BIO_C_SET_FILE_PTR, flags, (char *)file);

}

int BIO_read_filename(BIO *bio, const char *filename) {

  return (int)BIO_ctrl(bio, BIO_C_SET_FILENAME, BIO_CLOSE | BIO_FP_READ,

                       (char *)filename);

}

int BIO_write_filename(BIO *bio, const char *filename) {

  return (int)BIO_ctrl(bio, BIO_C_SET_FILENAME, BIO_CLOSE | BIO_FP_WRITE,

                       (char *)filename);

}

int BIO_append_filename(BIO *bio, const char *filename) {

  return (int)BIO_ctrl(bio, BIO_C_SET_FILENAME, BIO_CLOSE | BIO_FP_APPEND,

                       (char *)filename);

}

int BIO_rw_filename(BIO *bio, const char *filename) {

  return (int)BIO_ctrl(bio, BIO_C_SET_FILENAME,

                       BIO_CLOSE | BIO_FP_READ | BIO_FP_WRITE,

                       (char *)filename);

}

long BIO_tell(BIO *bio) { return BIO_ctrl(bio, BIO_C_FILE_TELL, 0, NULL); }

long BIO_seek(BIO *bio, long offset) {

  return BIO_ctrl(bio, BIO_C_FILE_SEEK, offset, NULL);

}