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  1. /*
  2.  * Copyright (C) 2006 Jakub Jermar
  3.  * All rights reserved.
  4.  *
  5.  * Redistribution and use in source and binary forms, with or without
  6.  * modification, are permitted provided that the following conditions
  7.  * are met:
  8.  *
  9.  * - Redistributions of source code must retain the above copyright
  10.  *   notice, this list of conditions and the following disclaimer.
  11.  * - Redistributions in binary form must reproduce the above copyright
  12.  *   notice, this list of conditions and the following disclaimer in the
  13.  *   documentation and/or other materials provided with the distribution.
  14.  * - The name of the author may not be used to endorse or promote products
  15.  *   derived from this software without specific prior written permission.
  16.  *
  17.  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  18.  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  19.  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  20.  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  21.  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  22.  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  23.  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  24.  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25.  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  26.  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27.  */
  28.  
  29. #include <as.h>
  30. #include <libc.h>
  31. #include <unistd.h>
  32. #include <task.h>
  33.  
  34. /** Create address space area.
  35.  *
  36.  * @param address Virtual address where to place new address space area.
  37.  * @param size Size of the area.
  38.  * @param flags Flags describing type of the area.
  39.  *
  40.  * @return address on success, (void *) -1 otherwise.
  41.  */
  42. void *as_area_create(void *address, size_t size, int flags)
  43. {
  44.     return (void *) __SYSCALL3(SYS_AS_AREA_CREATE, (sysarg_t ) address, (sysarg_t) size, (sysarg_t) flags);
  45. }
  46.  
  47. /** Resize address space area.
  48.  *
  49.  * @param address Virtual address pointing into already existing address space area.
  50.  * @param size New requested size of the area.
  51.  * @param flags Currently unused.
  52.  *
  53.  * @return Zero on success or a code from @ref errno.h on failure.
  54.  */
  55. int as_area_resize(void *address, size_t size, int flags)
  56. {
  57.     return __SYSCALL3(SYS_AS_AREA_RESIZE, (sysarg_t ) address, (sysarg_t) size, (sysarg_t) flags);
  58. }
  59.  
  60. /** Destroy address space area.
  61.  *
  62.  * @param address Virtual address pointing into the address space area being destroyed.
  63.  *
  64.  * @return Zero on success or a code from @ref errno.h on failure.
  65.  */
  66. int as_area_destroy(void *address)
  67. {
  68.     return __SYSCALL1(SYS_AS_AREA_DESTROY, (sysarg_t ) address);
  69. }
  70.  
  71. static size_t heapsize = 0;
  72. /* Start of heap linker symbol */
  73. extern char _heap;
  74.  
  75. /** Sbrk emulation
  76.  *
  77.  * @param size New area that should be allocated or negative,
  78.                if it should be shrinked
  79.  * @return Pointer to newly allocated area
  80.  */
  81. void *sbrk(ssize_t incr)
  82. {
  83.     int rc;
  84.     void *res;
  85.     /* Check for invalid values */
  86.     if (incr < 0 && -incr > heapsize)
  87.         return NULL;
  88.     /* Check for too large value */
  89.     if (incr > 0 && incr+heapsize < heapsize)
  90.         return NULL;
  91.     /* Check for too small values */
  92.     if (incr < 0 && incr+heapsize > heapsize)
  93.         return NULL;
  94.  
  95.     rc = as_area_resize(&_heap, heapsize + incr,0);
  96.     if (rc != 0)
  97.         return NULL;
  98.    
  99.     /* Compute start of new area */
  100.     res = (void *)&_heap + heapsize;
  101.  
  102.     heapsize += incr;
  103.  
  104.     return res;
  105. }
  106.