// SPDX-License-Identifier: GPL-2.0-or-later

/*

 * utils - miscellaneous I/O utilities for cryptsetup

 *

 * Copyright (C) 2004 Jana Saout <jana@saout.de>

 * Copyright (C) 2004-2007 Clemens Fruhwirth <clemens@endorphin.org>

 * Copyright (C) 2009-2025 Red Hat, Inc. All rights reserved.

 * Copyright (C) 2009-2025 Milan Broz

 */

#include <errno.h>

#include <limits.h>

#include <string.h>

#include <stdlib.h>

#include <stdint.h>

#include <unistd.h>

#include "utils_io.h"

/* coverity[ -taint_source : arg-1 ] */

static ssize_t _read_buffer(int fd, void *buf, size_t length, volatile int *quit)

{

  ssize_t r, read_size = 0;

  if (fd < 0 || !buf || length > SSIZE_MAX)

    return -EINVAL;

  do {

    r = read(fd, buf, length - read_size);

    if (r == -1 && errno != EINTR)

      return r;

    if (r > 0) {

      /* coverity[overflow:FALSE] */

      read_size += r;

      buf = (uint8_t*)buf + r;

    }

    if (r == 0 || (quit && *quit))

      return read_size;

  } while ((size_t)read_size != length);

  return (ssize_t)length;

}

ssize_t read_buffer(int fd, void *buf, size_t length)

{

  return _read_buffer(fd, buf, length, NULL);

}

ssize_t read_buffer_intr(int fd, void *buf, size_t length, volatile int *quit)

{

  return _read_buffer(fd, buf, length, quit);

}

static ssize_t _write_buffer(int fd, const void *buf, size_t length, volatile int *quit)

{

  ssize_t w, write_size = 0;

  if (fd < 0 || !buf || !length || length > SSIZE_MAX)

    return -EINVAL;

  do {

    w = write(fd, buf, length - (size_t)write_size);

    if (w < 0 && errno != EINTR)

      return w;

    if (w > 0) {

      /* coverity[overflow:FALSE] */

      write_size += w;

      buf = (const uint8_t*)buf + w;

    }

    if (w == 0 || (quit && *quit))

      return write_size;

  } while ((size_t)write_size != length);

  return write_size;

}

ssize_t write_buffer(int fd, const void *buf, size_t length)

{

  return _write_buffer(fd, buf, length, NULL);

}

ssize_t write_buffer_intr(int fd, const void *buf, size_t length, volatile int *quit)

{

  return _write_buffer(fd, buf, length, quit);

}

ssize_t write_blockwise(int fd, size_t bsize, size_t alignment,

      void *orig_buf, size_t length)

{

  void *hangover_buf = NULL, *buf = NULL;

  size_t hangover, solid;

  ssize_t r, ret = -1;

  if (fd == -1 || !orig_buf || !bsize || !alignment)

    return -1;

  hangover = length % bsize;

  solid = length - hangover;

  if ((size_t)orig_buf & (alignment - 1)) {

    if (posix_memalign(&buf, alignment, length))

      return -1;

    memcpy(buf, orig_buf, length);

  } else

    buf = orig_buf;

  if (solid) {

    r = write_buffer(fd, buf, solid);

    if (r < 0 || r != (ssize_t)solid)

      goto out;

  }

  if (hangover) {

    if (posix_memalign(&hangover_buf, alignment, bsize))

      goto out;

    memset(hangover_buf, 0, bsize);

    r = read_buffer(fd, hangover_buf, bsize);

    if (r < 0)

      goto out;

    if (lseek(fd, -(off_t)r, SEEK_CUR) < 0)

      goto out;

    memcpy(hangover_buf, (char*)buf + solid, hangover);

    r = write_buffer(fd, hangover_buf, bsize);

    if (r < 0 || r < (ssize_t)hangover)

      goto out;

  }

  ret = length;

out:

  free(hangover_buf);

  if (buf != orig_buf)

    free(buf);

  return ret;

}

ssize_t read_blockwise(int fd, size_t bsize, size_t alignment,

           void *orig_buf, size_t length)

{

  void *hangover_buf = NULL, *buf = NULL;

  size_t hangover, solid;

  ssize_t r, ret = -1;

  if (fd == -1 || !orig_buf || !bsize || !alignment)

    return -1;

  hangover = length % bsize;

  solid = length - hangover;

  if ((size_t)orig_buf & (alignment - 1)) {

    if (posix_memalign(&buf, alignment, length))

      return -1;

  } else

    buf = orig_buf;

  r = read_buffer(fd, buf, solid);

  if (r < 0 || r != (ssize_t)solid)

    goto out;

  if (hangover) {

    if (posix_memalign(&hangover_buf, alignment, bsize))

      goto out;

    r = read_buffer(fd, hangover_buf, bsize);

    if (r <  0 || r < (ssize_t)hangover)

      goto out;

    memcpy((char *)buf + solid, hangover_buf, hangover);

  }

  ret = length;

out:

  free(hangover_buf);

  if (buf != orig_buf) {

    if (ret != -1)

      memcpy(orig_buf, buf, length);

    free(buf);

  }

  return ret;

}

/*

 * Combines llseek with blockwise write. write_blockwise can already deal with short writes

 * but we also need a function to deal with short writes at the start. But this information

 * is implicitly included in the read/write offset, which can not be set to non-aligned

 * boundaries. Hence, we combine llseek with write.

 */

ssize_t write_lseek_blockwise(int fd, size_t bsize, size_t alignment,

            void *buf, size_t length, off_t offset)

{

  void *frontPadBuf = NULL;

  size_t frontHang, innerCount = 0;

  ssize_t r, ret = -1;

  if (fd == -1 || !buf || !bsize || !alignment)

    return -1;

  if (offset < 0)

    offset = lseek(fd, offset, SEEK_END);

  if (offset < 0)

    return -1;

  frontHang = offset % bsize;

  if (lseek(fd, offset - frontHang, SEEK_SET) < 0)

    return -1;

  if (frontHang && length) {

    if (posix_memalign(&frontPadBuf, alignment, bsize))

      return -1;

    innerCount = bsize - frontHang;

    if (innerCount > length)

      innerCount = length;

    r = read_buffer(fd, frontPadBuf, bsize);

    if (r < 0 || r < (ssize_t)(frontHang + innerCount))

      goto out;

    memcpy((char*)frontPadBuf + frontHang, buf, innerCount);

    if (lseek(fd, offset - frontHang, SEEK_SET) < 0)

      goto out;

    r = write_buffer(fd, frontPadBuf, bsize);

    if (r < 0 || r != (ssize_t)bsize)

      goto out;

    buf = (char*)buf + innerCount;

    length -= innerCount;

  }

  ret = length ? write_blockwise(fd, bsize, alignment, buf, length) : 0;

  if (ret >= 0)

    ret += innerCount;

out:

  free(frontPadBuf);

  return ret;

}

ssize_t read_lseek_blockwise(int fd, size_t bsize, size_t alignment,

           void *buf, size_t length, off_t offset)

{

  void *frontPadBuf = NULL;

  size_t frontHang, innerCount = 0;

  ssize_t r, ret = -1;

  if (fd == -1 || !buf || bsize <= 0)

    return -1;

  if (offset < 0)

    offset = lseek(fd, offset, SEEK_END);

  if (offset < 0)

    return -1;

  frontHang = offset % bsize;

  if (lseek(fd, offset - frontHang, SEEK_SET) < 0)

    return -1;

  if (frontHang && length) {

    if (posix_memalign(&frontPadBuf, alignment, bsize))

      return -1;

    innerCount = bsize - frontHang;

    if (innerCount > length)

      innerCount = length;

    r = read_buffer(fd, frontPadBuf, bsize);

    if (r < 0 || r < (ssize_t)(frontHang + innerCount))

      goto out;

    memcpy(buf, (char*)frontPadBuf + frontHang, innerCount);

    buf = (char*)buf + innerCount;

    length -= innerCount;

  }

  ret = length ? read_blockwise(fd, bsize, alignment, buf, length) : 0;

  if (ret >= 0)

    ret += innerCount;

out:

  free(frontPadBuf);

  return ret;

}