mirror of
https://github.com/jart/cosmopolitan.git
synced 2025-02-07 06:53:33 +00:00
42a3bb729a
It's now possible to use execve() when the parent process isn't built by cosmo. In such cases, the current process will kill all threads and then linger around, waiting for the newly created process to die, and then we propagate its exit code to the parent. This should help bazel and others Allocating private anonymous memory is now 5x faster on Windows. This is thanks to VirtualAlloc() which is faster than the file mapping APIs. The fork() function also now goes 30% faster, since we are able to avoid the VirtualProtect() calls on mappings in most cases now. Fixes #1253
111 lines
4.4 KiB
C
111 lines
4.4 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 2021 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/calls.h"
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#include "libc/calls/internal.h"
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#include "libc/calls/metalfile.internal.h"
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#include "libc/macros.h"
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#include "libc/runtime/pc.internal.h"
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#include "libc/str/str.h"
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#include "libc/sysv/consts/prot.h"
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#include "libc/sysv/errfuns.h"
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#ifdef __x86_64__
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#define MAP_ANONYMOUS_linux 0x00000020
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#define MAP_FIXED_linux 0x00000010
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static uint64_t sys_mmap_metal_break;
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void *sys_mmap_metal(void *vaddr, size_t size, int prot, int flags, int fd,
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int64_t off) {
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/* asan runtime depends on this function */
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size_t i;
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struct mman *mm;
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uint64_t addr, faddr = 0, page, e, *pte, *fdpte, *pml4t;
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mm = __get_mm();
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pml4t = __get_pml4t();
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size = ROUNDUP(size, 4096);
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addr = (uint64_t)vaddr;
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if (!(flags & MAP_ANONYMOUS_linux)) {
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struct Fd *sfd;
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struct MetalFile *file;
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if (off < 0 || fd < 0 || fd >= g_fds.n)
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return MAP_FAILED;
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sfd = &g_fds.p[fd];
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if (sfd->kind != kFdFile)
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return MAP_FAILED;
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file = (struct MetalFile *)sfd->handle;
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/* TODO: allow mapping partial page at end of file, if file size not
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* multiple of page size */
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if (off > file->size || size > file->size - off)
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return MAP_FAILED;
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faddr = (uint64_t)file->base + off;
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if (faddr % 4096 != 0)
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return MAP_FAILED;
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}
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if (!(flags & MAP_FIXED_linux)) {
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if (!addr) {
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addr = 4096;
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} else {
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addr = ROUNDUP(addr, 4096);
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}
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for (i = 0; i < size; i += 4096) {
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pte = __get_virtual(mm, pml4t, addr + i, false);
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if (pte && (*pte & (PAGE_V | PAGE_RSRV))) {
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addr = MAX(addr, sys_mmap_metal_break) + i + 4096;
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i = 0;
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}
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}
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sys_mmap_metal_break = MAX(addr + size, sys_mmap_metal_break);
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}
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for (i = 0; i < size; i += 4096) {
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pte = __get_virtual(mm, pml4t, addr + i, true);
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if (pte) {
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if ((flags & MAP_ANONYMOUS_linux)) {
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page = __new_page(mm);
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if (!page)
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return MAP_FAILED;
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__clear_page(BANE + page);
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e = page | PAGE_RSRV | PAGE_U;
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if ((prot & PROT_WRITE))
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e |= PAGE_V | PAGE_RW;
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else if ((prot & (PROT_READ | PROT_EXEC)))
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e |= PAGE_V;
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if (!(prot & PROT_EXEC))
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e |= PAGE_XD;
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} else {
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fdpte = __get_virtual(mm, pml4t, faddr + i, false);
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e = *fdpte | PAGE_RSRV | PAGE_U;
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page = e & PAGE_TA;
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if (!(prot & PROT_WRITE))
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e &= ~PAGE_RW;
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if (!(prot & PROT_EXEC))
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e |= PAGE_XD;
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}
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__ref_page(mm, pml4t, page);
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*pte = e;
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invlpg(addr + i);
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} else {
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addr = -1;
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break;
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}
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}
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return (void *)addr;
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}
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#endif /* __x86_64__ */
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