mirror of
https://github.com/jart/cosmopolitan.git
synced 2025-02-12 09:17:53 +00:00
464858dbb4
This fixes a regression in mmap(MAP_FIXED) on Windows caused by a recent revision. This change also fixes ZipOS so it no longer needs a MAP_FIXED mapping to open files from the PKZIP store. The memory mapping mutex was implemented incorrectly earlier which meant that ftrace and strace could cause cause crashes. This lock and other recursive mutexes are rewritten so that it should be provable that recursive mutexes in cosmopolitan are asynchronous signal safe.
222 lines
8.1 KiB
C
222 lines
8.1 KiB
C
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
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│ vi: set et ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi │
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╞══════════════════════════════════════════════════════════════════════════════╡
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│ Copyright 2020 Justine Alexandra Roberts Tunney │
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│ │
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│ Permission to use, copy, modify, and/or distribute this software for │
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│ any purpose with or without fee is hereby granted, provided that the │
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│ above copyright notice and this permission notice appear in all copies. │
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│ │
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│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
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│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
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│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
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│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
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│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
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│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
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│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
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│ PERFORMANCE OF THIS SOFTWARE. │
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╚─────────────────────────────────────────────────────────────────────────────*/
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#include "libc/calls/struct/sigset.internal.h"
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#include "libc/calls/syscall-sysv.internal.h"
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#include "libc/dce.h"
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#include "libc/intrin/describeflags.internal.h"
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#include "libc/intrin/directmap.internal.h"
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#include "libc/intrin/dll.h"
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#include "libc/intrin/kprintf.h"
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#include "libc/intrin/maps.h"
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#include "libc/intrin/strace.internal.h"
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#include "libc/nt/memory.h"
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#include "libc/runtime/internal.h"
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#include "libc/runtime/runtime.h"
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#include "libc/stdio/sysparam.h"
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#include "libc/sysv/consts/auxv.h"
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#include "libc/sysv/consts/map.h"
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#include "libc/sysv/consts/prot.h"
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#include "libc/sysv/errfuns.h"
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#define PGUP(x) (((x) + pagesz - 1) & -pagesz)
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static int __mprotect_chunk(char *addr, size_t size, int prot, bool iscow) {
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if (!IsWindows())
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return sys_mprotect(addr, size, prot);
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uint32_t op;
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if (!VirtualProtect(addr, size, __prot2nt(prot, iscow), &op))
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return -1;
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return 0;
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}
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int __mprotect(char *addr, size_t size, int prot) {
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// unix checks prot before checking size
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if (prot & ~(PROT_READ | PROT_WRITE | PROT_EXEC))
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return einval();
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// make new technology consistent with unix
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if (!size)
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return 0;
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// unix checks prot before checking size
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int pagesz = getauxval(AT_PAGESZ);
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if ((intptr_t)addr & (pagesz - 1))
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return einval();
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// change mappings
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int rc = 0;
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__maps_lock();
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bool found = false;
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struct Map *map = __maps.maps;
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struct Map **prev = &__maps.maps;
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while (map) {
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char *map_addr = map->addr;
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size_t map_size = map->size;
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struct Map *next = map->next;
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char *beg = MAX(addr, map_addr);
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char *end = MIN(addr + PGUP(size), map_addr + PGUP(map_size));
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if (beg < end) {
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found = true;
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if (addr <= map_addr && addr + PGUP(size) >= map_addr + PGUP(map_size)) {
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// change protection of entire mapping
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if (!__mprotect_chunk(map_addr, map_size, prot, map->iscow)) {
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map->prot = prot;
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} else {
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rc = -1;
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}
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} else if (IsWindows()) {
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// windows does allow changing protection at 4096 byte chunks
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// however we currently don't have data structures that track
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// this within the 64 kb map granules that can't be broken up
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if (__mprotect_chunk(beg, end - beg, prot, map->iscow) == -1)
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rc = -1;
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} else if (addr <= map_addr) {
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// cleave lefthand side of mapping
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size_t left = PGUP(addr + size - map_addr);
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size_t right = map_size - left;
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struct Map *leftmap;
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if ((leftmap = __maps_alloc())) {
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if (!__mprotect_chunk(map_addr, left, prot, false)) {
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leftmap->next = map;
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leftmap->addr = map_addr;
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leftmap->size = left;
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leftmap->prot = prot;
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leftmap->off = map->off;
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leftmap->flags = map->flags;
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map->addr += left;
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map->size = right;
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if (!(map->flags & MAP_ANONYMOUS))
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map->off += left;
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dll_make_first(&__maps.used, &leftmap->elem);
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*prev = leftmap;
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__maps.count += 1;
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__maps_check();
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} else {
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__maps_free(leftmap);
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rc = -1;
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}
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} else {
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rc = -1;
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}
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} else if (addr + PGUP(size) >= map_addr + PGUP(map_size)) {
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// cleave righthand side of mapping
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size_t left = addr - map_addr;
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size_t right = map_addr + map_size - addr;
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struct Map *leftmap;
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if ((leftmap = __maps_alloc())) {
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if (!__mprotect_chunk(map_addr + left, right, prot, false)) {
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leftmap->next = map;
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leftmap->addr = map_addr;
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leftmap->size = left;
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leftmap->off = map->off;
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leftmap->prot = map->prot;
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leftmap->flags = map->flags;
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map->addr += left;
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map->size = right;
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map->prot = prot;
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if (!(map->flags & MAP_ANONYMOUS))
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map->off += left;
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dll_make_first(&__maps.used, &leftmap->elem);
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*prev = leftmap;
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__maps.count += 1;
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__maps_check();
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} else {
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__maps_free(leftmap);
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rc = -1;
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}
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} else {
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rc = -1;
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}
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} else {
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// punch hole in mapping
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size_t left = addr - map_addr;
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size_t middle = PGUP(size);
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size_t right = map_size - middle - left;
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struct Map *leftmap;
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if ((leftmap = __maps_alloc())) {
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struct Map *midlmap;
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if ((midlmap = __maps_alloc())) {
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if (!__mprotect_chunk(map_addr + left, middle, prot, false)) {
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leftmap->next = midlmap;
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leftmap->addr = map_addr;
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leftmap->size = left;
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leftmap->off = map->off;
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leftmap->prot = map->prot;
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leftmap->flags = map->flags;
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midlmap->next = map;
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midlmap->addr = map_addr + left;
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midlmap->size = middle;
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midlmap->off = (map->flags & MAP_ANONYMOUS) ? 0 : map->off + left;
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midlmap->prot = prot;
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midlmap->flags = map->flags;
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map->addr += left + middle;
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map->size = right;
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if (!(map->flags & MAP_ANONYMOUS))
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map->off += left + middle;
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dll_make_first(&__maps.used, &leftmap->elem);
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dll_make_first(&__maps.used, &midlmap->elem);
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*prev = leftmap;
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__maps.count += 2;
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__maps_check();
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} else {
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__maps_free(midlmap);
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__maps_free(leftmap);
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rc = -1;
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}
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} else {
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__maps_free(leftmap);
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rc = -1;
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}
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} else {
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rc = -1;
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}
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}
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}
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prev = &map->next;
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map = next;
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}
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// allow user to change mappings unknown to cosmo runtime
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if (!found)
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rc = __mprotect_chunk(addr, size, prot, false);
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__maps_unlock();
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return rc;
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}
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/**
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* Modifies restrictions on virtual memory address range.
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*
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* @param addr needs to be 4kb aligned
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* @param prot can have PROT_{NONE,READ,WRITE,EXEC}
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* @return 0 on success, or -1 w/ errno
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* @raise ENOMEM on tracking memory oom
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* @see mmap()
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*/
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int mprotect(void *addr, size_t size, int prot) {
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int rc;
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rc = __mprotect(addr, size, prot);
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STRACE("mprotect(%p, %'zu, %s) → %d% m", addr, size, DescribeProtFlags(prot),
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rc);
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return rc;
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}
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