mirror of
https://github.com/jart/cosmopolitan.git
synced 2025-04-02 05:48:44 +00:00
6ffed14b9c
Actually Portable Executable now supports Android. Cosmo's old mmap code required a 47 bit address space. The new implementation is very agnostic and supports both smaller address spaces (e.g. embedded) and even modern 56-bit PML5T paging for x86 which finally came true on Zen4 Threadripper Cosmopolitan no longer requires UNIX systems to observe the Windows 64kb granularity; i.e. sysconf(_SC_PAGE_SIZE) will now report the host native page size. This fixes a longstanding POSIX conformance issue, concerning file mappings that overlap the end of file. Other aspects of conformance have been improved too, such as the subtleties of address assignment and and the various subtleties surrounding MAP_FIXED and MAP_FIXED_NOREPLACE On Windows, mappings larger than 100 megabytes won't be broken down into thousands of independent 64kb mappings. Support for MAP_STACK is removed by this change; please use NewCosmoStack() instead. Stack overflow avoidance is now being implemented using the POSIX thread APIs. Please use GetStackBottom() and GetStackAddr(), instead of the old error-prone GetStackAddr() and HaveStackMemory() APIs which are removed.
215 lines
7.9 KiB
C
215 lines
7.9 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/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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_Atomic(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 = addr + size - map_addr;
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size_t right = map_addr + map_size - (addr + size);
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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->off != -1)
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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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} 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->off != -1)
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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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} 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->off == -1 ? -1 : 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->off != -1)
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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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} 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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