mirror of
https://git.proxmox.com/git/wasi-libc
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ca9046d872
For now, this means using `//`-style comments in .c source files (though not public header files), and spaces rather than tabs. No strong opinion here; this is just what the majority of the current code is using. This also synchronizes basics/crt/crt1.c with libc-bottom-half's version, though this is just a cleanup as the former isn't currently used by the main wasi-libc build.
33 lines
815 B
C
33 lines
815 B
C
#include <unistd.h>
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#include <stdlib.h>
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#include <errno.h>
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#include <__macro_PAGESIZE.h>
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// Bare-bones implementation of sbrk.
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void *sbrk(intptr_t increment) {
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// sbrk(0) returns the current memory size.
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if (increment == 0) {
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// The wasm spec doesn't guarantee that memory.grow of 0 always succeeds.
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return (void *)(__builtin_wasm_memory_size(0) * PAGESIZE);
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}
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// We only support page-size increments.
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if (increment % PAGESIZE != 0) {
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abort();
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}
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// WebAssembly doesn't support shrinking linear memory.
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if (increment < 0) {
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abort();
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}
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uintptr_t old = __builtin_wasm_memory_grow(0, (uintptr_t)increment / PAGESIZE);
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if (old == SIZE_MAX) {
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errno = ENOMEM;
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return (void *)-1;
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}
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return (void *)(old * PAGESIZE);
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}
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