Contiki-NG
syscalls.c
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1 /*
2  * Copyright (c) 2014, Institute for Pervasive Computing, ETH Zurich.
3  * All rights reserved.
4  *
5  * Author: Andreas Dröscher <contiki@anticat.ch>
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  * 1. Redistributions of source code must retain the above copyright
11  * notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  * notice, this list of conditions and the following disclaimer in the
14  * documentation and/or other materials provided with the distribution.
15  * 3. Neither the name of the Institute nor the names of its contributors
16  * may be used to endorse or promote products derived from this software
17  * without specific prior written permission.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS "AS IS" AND
20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22  * ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29  * SUCH DAMAGE.
30  */
31 /**
32  * \addtogroup lib
33  * @{
34  *
35  * \defgroup newlib Generic Newlib customizations
36  *
37  * Library providing generic implementations of Newlib features for Contiki
38  * @{
39  *
40  * \file
41  * System calls
42  */
43 #include <sys/types.h>
44 #include <errno.h>
45 #include <stdint.h>
46 #include <stdio.h>
47 /*---------------------------------------------------------------------------*/
48 #define DEBUG 0
49 #if DEBUG
50 #define PRINTF(...) printf(__VA_ARGS__)
51 #else
52 #define PRINTF(...)
53 #endif
54 /*---------------------------------------------------------------------------*/
55 /**
56  * \brief Enlarges the allocated heap space
57  * \param incr Number of bytes by which to increase the heap space
58  * \return The previous end of heap on success (which is also a pointer to the
59  * start of the newly allocated memory if \p incr is positive), or
60  * <tt>(caddr_t)-1</tt> with \c errno set to \c ENOMEM on error
61  */
62 caddr_t
63 _sbrk(int incr)
64 {
65  /*
66  * Newlib's _sbrk_r() assumes that this global errno variable is used here,
67  * which is different from the errno definition provided by <errno.h>.
68  */
69 #undef errno
70  extern int errno;
71 
72  /* Heap boundaries from linker script. */
73  extern uint8_t _heap;
74  extern uint8_t _eheap;
75 
76  static uint8_t *heap_end = &_heap;
77  uint8_t *prev_heap_end = heap_end;
78 
79  if(heap_end + incr > &_eheap) {
80  PRINTF("Out of heap space!\n");
81  errno = ENOMEM;
82  return (caddr_t)-1;
83  }
84 
85  heap_end += incr;
86  return (caddr_t)prev_heap_end;
87 }
88 
89 /**
90  * @}
91  * @}
92  */
caddr_t _sbrk(int incr)
Enlarges the allocated heap space.
Definition: syscalls.c:63