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Work towards improving signals and processes

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Justine Tunney 2021-01-27 19:34:02 -08:00
parent de703b182c
commit d7ac16a9ed
96 changed files with 1474 additions and 427 deletions
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libc/runtime/brk.c Normal file
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/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2021 Justine Alexandra Roberts Tunney │
│ │
│ Permission to use, copy, modify, and/or distribute this software for │
│ any purpose with or without fee is hereby granted, provided that the │
│ above copyright notice and this permission notice appear in all copies. │
│ │
│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
│ PERFORMANCE OF THIS SOFTWARE. │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/assert.h"
#include "libc/calls/calls.h"
#include "libc/macros.h"
#include "libc/runtime/runtime.h"
#include "libc/sysv/consts/map.h"
#include "libc/sysv/consts/prot.h"
#include "libc/sysv/errfuns.h"
uintptr_t __break;
/**
* Sets end of data section.
*
* This can be used to allocate and deallocate memory. It won't
* conflict with malloc() and mmap(NULL, ...) allocations since
* APE binaries load the image at 0x400000 and does allocations
* starting at 0x100080000000. You should consult _end, or call
* sbrk(NULL), to figure out where the existing break is first.
*
* @return 0 on success or -1 w/ errno
* @see mmap(), sbrk(), _end
*/
int brk(void *end) {
int rc;
uintptr_t x;
if (!__break) __break = (uintptr_t)_end;
x = (uintptr_t)end;
if (x < (uintptr_t)_end) x = (uintptr_t)_end;
x = ROUNDUP(x, FRAMESIZE);
if (x == __break) return 0;
/* allocate one frame at a time due to nt pickiness */
for (; x > __break; __break += FRAMESIZE) {
if (mmap((void *)__break, FRAMESIZE, PROT_READ | PROT_WRITE,
MAP_FIXED | MAP_PRIVATE | MAP_ANONYMOUS, -1, 0) == MAP_FAILED) {
return -1;
}
}
for (rc = 0; x < __break; __break -= FRAMESIZE) {
rc |= munmap((void *)(__break - FRAMESIZE), FRAMESIZE);
}
return 0;
}
/**
* Adjusts end of data section.
*
* This shrinks or increases the program break by delta bytes. On
* success, the previous program break is returned. It's possible
* to pass zero to this function to get the current program break
*
* @return old break on success or -1 w/ errno
* @see mmap(), brk(), _end
*/
void *sbrk(intptr_t delta) {
uintptr_t oldbreak;
if (!__break) __break = (uintptr_t)_end;
oldbreak = __break;
return (void *)(brk((void *)(__break + delta)) != -1 ? oldbreak : -1);
}