mirror of
https://github.com/jart/cosmopolitan.git
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f684e348d4
- Document sigaction() - Simplify New Technology fork() code - Testing and many bug fixes for mprotect() - Distribute Intel Xed ILD in the amalgamation - Turn Xed enums into defines to avoid DWARF bloat - Improve polyfilling of SA_SIGINFO on BSDs and fix bugs - setpgid(getpid(), getpid()) on Windows will ignore CTRL-C - Work around issues relating to NT mappings being executable - Permit automatic executable stack override via `ape_stack_pf`
98 lines
4.5 KiB
C
98 lines
4.5 KiB
C
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
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│vi: set net 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/assert.h"
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#include "libc/calls/internal.h"
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#include "libc/nt/enum/filemapflags.h"
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#include "libc/nt/enum/pageflags.h"
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#include "libc/nt/memory.h"
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#include "libc/nt/runtime.h"
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#include "libc/runtime/directmap.internal.h"
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#include "libc/sysv/consts/map.h"
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#include "libc/sysv/consts/o.h"
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#include "libc/sysv/consts/prot.h"
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textwindows noasan struct DirectMap sys_mmap_nt(void *addr, size_t size,
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int prot, int flags, int fd,
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int64_t off) {
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size_t i;
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bool iscow;
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int64_t handle;
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uint32_t oldprot;
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struct DirectMap dm;
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struct ProtectNt fl;
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const struct NtSecurityAttributes *sec;
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if (fd != -1) {
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handle = g_fds.p[fd].handle;
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} else {
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handle = kNtInvalidHandleValue;
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}
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if (flags & MAP_PRIVATE) {
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sec = 0; // MAP_PRIVATE isn't inherited across fork()
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} else {
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sec = &kNtIsInheritable; // MAP_SHARED gives us zero-copy fork()
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}
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// nt will whine under many circumstances if we change the execute bit
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// later using mprotect(). the workaround is to always request execute
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// and then virtualprotect() it away until we actually need it. please
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// note that open-nt.c always requests an kNtGenericExecute accessmask
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iscow = false;
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if (handle != -1) {
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if (flags & MAP_PRIVATE) {
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// windows has cow pages but they can't propagate across fork()
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// that means we only get copy-on-write for the root process :(
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fl = (struct ProtectNt){kNtPageExecuteWritecopy,
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kNtFileMapCopy | kNtFileMapExecute};
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iscow = true;
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} else {
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assert(flags & MAP_SHARED);
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if ((g_fds.p[fd].flags & O_ACCMODE) == O_RDONLY) {
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fl = (struct ProtectNt){kNtPageExecuteRead,
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kNtFileMapRead | kNtFileMapExecute};
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} else {
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fl = (struct ProtectNt){kNtPageExecuteReadwrite,
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kNtFileMapWrite | kNtFileMapExecute};
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}
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}
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} else {
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assert(flags & MAP_ANONYMOUS);
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fl = (struct ProtectNt){kNtPageExecuteReadwrite,
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kNtFileMapWrite | kNtFileMapExecute};
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}
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if ((dm.maphandle = CreateFileMapping(handle, sec, fl.flags1,
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(size + off) >> 32, (size + off), 0))) {
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if ((dm.addr = MapViewOfFileEx(dm.maphandle, fl.flags2, off >> 32, off,
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size, addr))) {
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if (VirtualProtect(addr, size, __prot2nt(prot, iscow), &oldprot)) {
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return dm;
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} else {
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return dm;
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UnmapViewOfFile(dm.addr);
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}
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}
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CloseHandle(dm.maphandle);
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}
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dm.maphandle = kNtInvalidHandleValue;
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dm.addr = (void *)(intptr_t)-1;
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return dm;
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}
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