blob: a26b75e9e3e52d0a96629d548cd23974eed518a0 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
|
#include <unistd.h>
#include <stdlib.h>
#include <errno.h>
#include <__macro_PAGESIZE.h>
// Bare-bones implementation of sbrk.
void *sbrk(intptr_t increment) {
// sbrk(0) returns the current memory size.
if (increment == 0) {
// The wasm spec doesn't guarantee that memory.grow of 0 always succeeds.
return (void *)(__builtin_wasm_memory_size(0) * PAGESIZE);
}
// We only support page-size increments.
if (increment % PAGESIZE != 0) {
abort();
}
// WebAssembly doesn't support shrinking linear memory.
if (increment < 0) {
abort();
}
uintptr_t old = __builtin_wasm_memory_grow(0, (uintptr_t)increment / PAGESIZE);
if (old == SIZE_MAX) {
errno = ENOMEM;
return (void *)-1;
}
return (void *)(old * PAGESIZE);
}
|
