kmm_sbrk.c 3.7 KB

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  1. /****************************************************************************
  2. * mm/kmm_heap/kmm_sbrk.c
  3. *
  4. * Copyright (C) 2014 Gregory Nutt. All rights reserved.
  5. * Author: Gregory Nutt <gnutt@nuttx.org>
  6. *
  7. * Redistribution and use in source and binary forms, with or without
  8. * modification, are permitted provided that the following conditions
  9. * are met:
  10. *
  11. * 1. Redistributions of source code must retain the above copyright
  12. * notice, this list of conditions and the following disclaimer.
  13. * 2. Redistributions in binary form must reproduce the above copyright
  14. * notice, this list of conditions and the following disclaimer in
  15. * the documentation and/or other materials provided with the
  16. * distribution.
  17. * 3. Neither the name NuttX nor the names of its contributors may be
  18. * used to endorse or promote products derived from this software
  19. * without specific prior written permission.
  20. *
  21. * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  22. * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  23. * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  24. * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
  25. * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  26. * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
  27. * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
  28. * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
  29. * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  30. * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
  31. * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  32. * POSSIBILITY OF SUCH DAMAGE.
  33. *
  34. ****************************************************************************/
  35. /****************************************************************************
  36. * Included Files
  37. ****************************************************************************/
  38. #include <nuttx/config.h>
  39. #include <nuttx/mm/mm.h>
  40. #if defined(CONFIG_BUILD_KERNEL) && defined(__KERNEL__)
  41. /****************************************************************************
  42. * Public Functions
  43. ****************************************************************************/
  44. /****************************************************************************
  45. * Name: kmm_sbrk
  46. *
  47. * Description:
  48. * The sbrk() function is used to change the amount of space allocated
  49. * for the calling process. The change is made by resetting the process'
  50. * break value and allocating the appropriate amount of space. The amount
  51. * of allocated space increases as the break value increases.
  52. *
  53. * The sbrk() function adds 'incr' bytes to the break value and changes
  54. * the allocated space accordingly. If incr is negative, the amount of
  55. * allocated space is decreased by incr bytes. The current value of the
  56. * program break is returned by sbrk(0).
  57. *
  58. * Input Parameters:
  59. * incr - Specifies the number of bytes to add or to remove from the
  60. * space allocated for the process.
  61. *
  62. * Returned Value:
  63. * Upon successful completion, sbrk() returns the prior break value.
  64. * Otherwise, it returns (void *)-1 and sets errno to indicate the
  65. * error:
  66. *
  67. * ENOMEM - The requested change would allocate more space than
  68. * allowed under system limits.
  69. * EAGAIN - The total amount of system memory available for allocation
  70. * to this process is temporarily insufficient. This may occur even
  71. * though the space requested was less than the maximum data segment
  72. * size.
  73. *
  74. ****************************************************************************/
  75. FAR void *kmm_sbrk(intptr_t incr)
  76. {
  77. return mm_sbrk(&g_kmmheap, incr, UINTPTR_MAX);
  78. }
  79. #endif /* CONFIG_BUILD_KERNEL && __KERNEL__ */