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/* sbrk.c - Change data segment size */
/* Written 2000 by Werner Almesberger */
/* Modified 2003-2004 for klibc by H. Peter Anvin */
#include <stddef.h>
#include <unistd.h>
#include <inttypes.h>
#include <errno.h>
#include "malloc.h"
char *__current_brk; /* Common with brk.c */
/* p is an address, a is alignment; must be a power of 2 */
static inline void *align_up(void *p, uintptr_t a)
{
return (void *) (((uintptr_t)p + a-1) & ~(a-1));
}
void *sbrk(ptrdiff_t increment)
{
char *start, *end, *new_brk;
if (!__current_brk)
__current_brk = __brk(NULL);
start = align_up(__current_brk, SBRK_ALIGNMENT);
end = start + increment;
new_brk = __brk(end);
if (new_brk == (void *)-1)
return (void *)-1;
else if (new_brk < end) {
errno = ENOMEM;
return (void *) -1;
}
__current_brk = new_brk;
return end;
}
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