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https://github.com/jart/cosmopolitan.git
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db0d8dd806
The "no modify self" variant of Actually Portable Executable is now
supported on all platforms. If you use `$(APE_NO_MODIFY_SELF)` then
ld.bfd will embed a 4096 byte ELF binary and a 4096 byte Macho file
which are installed on the fly to ${TMPDIR:-/tmp}, which enables us
launch the executable, without needing to copy the whole executable
To prevent it from copying a tiny executable to your temp directory
you need to install the `ape` command (renamed from ape-loader), to
a system path. For example:
# FreeBSD / NetBSD / OpenBSD
make -j8 o//ape/ape
cp o//ape/ape /usr/bin/ape
# Mac OS
# make -j8 o//ape/ape.macho
curl https://justine.lol/ape.macho >/usr/bin/ape
chmod +x /usr/bin/ape
On Linux you can get even more performance with the new binfmt_misc
support which makes launching non-modifying APE binaries as fast as
launching ELF executables. Running the following command:
# Linux
ape/apeinstall.sh
Will copy APE loader to /usr/bin/ape and register with binfmt_misc
Lastly, this change also fixes a really interesting race condition
with OpenBSD thread joining.
160 lines
9 KiB
C
160 lines
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 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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╠──────────────────────────────────────────────────────▌▀▄─▐──▀▄─▐▄─▐▄▐▄─▐▄─▐▄─│
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│ αcτµαlly pδrταblε εxεcµταblε § no-frills virtual memory management │
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╚─────────────────────────────────────────────────────────────────────────────*/
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#include "ape/relocations.h"
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#include "libc/elf/def.h"
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#include "libc/elf/struct/phdr.h"
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#include "libc/macros.internal.h"
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#include "libc/nexgen32e/uart.internal.h"
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#include "libc/runtime/e820.internal.h"
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#include "libc/runtime/metalprintf.internal.h"
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#include "libc/runtime/pc.internal.h"
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#include "libc/runtime/runtime.h"
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/**
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* Allocates new page of physical memory.
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*/
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noasan texthead uint64_t __new_page(struct mman *mm) {
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uint64_t p;
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if (mm->pdpi == mm->e820n) {
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/* TODO: reclaim free pages */
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return 0;
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}
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while (mm->pdp >= mm->e820[mm->pdpi].addr + mm->e820[mm->pdpi].size) {
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if (++mm->pdpi == mm->e820n) return 0;
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mm->pdp = mm->e820[mm->pdpi].addr;
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}
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p = mm->pdp;
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mm->pdp += 4096;
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return p;
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}
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/**
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* Returns pointer to page table entry for page at virtual address.
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* Additional page tables are allocated if needed as a side-effect.
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*/
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noasan textreal uint64_t *__get_virtual(struct mman *mm, uint64_t *t,
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int64_t vaddr, bool maketables) {
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uint64_t *e, p;
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unsigned char h;
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for (h = 39;; h -= 9) {
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e = t + ((vaddr >> h) & 511);
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if (h == 12) return e;
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if (!(*e & PAGE_V)) {
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if (!maketables) return NULL;
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if (!(p = __new_page(mm))) return NULL;
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*e = p | PAGE_V | PAGE_RW;
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}
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t = (uint64_t *)(BANE + (*e & PAGE_TA));
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}
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}
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/**
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* Sorts, rounds, and filters BIOS memory map.
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*/
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static noasan texthead void __normalize_e820(struct mman *mm) {
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uint64_t a, b;
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uint64_t x, y;
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unsigned i, j, n;
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for (n = i = 0; mm->e820[i].size; ++i) {
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mm->e820[n] = mm->e820[i];
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x = mm->e820[n].addr;
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y = mm->e820[n].addr + mm->e820[n].size;
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a = ROUNDUP(x, 4096);
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b = ROUNDDOWN(y, 4096) - a;
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if (b > 0 && mm->e820[i].type == kMemoryUsable) {
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mm->e820[n].addr = a;
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mm->e820[n].size = b;
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++n;
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}
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}
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for (i = 1; i < n; ++i) {
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for (j = i; j > 0 && mm->e820[i].addr < mm->e820[j - 1].addr; --j) {
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mm->e820[j] = mm->e820[j - 1];
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}
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mm->e820[j] = mm->e820[i];
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}
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mm->pdp = MAX(0x80000, mm->e820[0].addr);
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mm->pdpi = 0;
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mm->e820n = n;
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}
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/**
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* Identity maps all usable physical memory to its negative address.
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*/
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static noasan texthead void __invert_memory(struct mman *mm, uint64_t *pml4t) {
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uint64_t i, j, *m, p, pe;
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for (i = 0; i < mm->e820n; ++i) {
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for (p = mm->e820[i].addr, pe = mm->e820[i].addr + mm->e820[i].size;
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p + 0x200000 < pe; p += 4096) {
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m = __get_virtual(mm, pml4t, BANE + p, true);
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if (m && !(*m & PAGE_V)) {
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*m = p | PAGE_V | PAGE_RW;
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}
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}
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}
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}
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noasan texthead void __setup_mman(struct mman *mm, uint64_t *pml4t) {
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__normalize_e820(mm);
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__invert_memory(mm, pml4t);
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}
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/**
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* Maps APE-defined ELF program headers into memory and clears BSS.
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*/
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noasan textreal void __map_phdrs(struct mman *mm, uint64_t *pml4t, uint64_t b) {
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struct Elf64_Phdr *p;
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uint64_t i, f, v, m, *e;
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extern char ape_phdrs[] __attribute__((__weak__));
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extern char ape_phdrs_end[] __attribute__((__weak__));
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__setup_mman(mm, pml4t);
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for (p = (struct Elf64_Phdr *)REAL(ape_phdrs), m = 0;
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p < (struct Elf64_Phdr *)REAL(ape_phdrs_end); ++p) {
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if (p->p_type == PT_LOAD || p->p_type == PT_GNU_STACK) {
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f = PAGE_V | PAGE_U;
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if (p->p_flags & PF_W) f |= PAGE_RW;
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for (i = 0; i < p->p_memsz; i += 4096) {
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if (i < p->p_filesz) {
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v = b + p->p_offset + i;
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m = MAX(m, v);
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} else {
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v = __clear_page(__new_page(mm));
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}
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*__get_virtual(mm, pml4t, p->p_vaddr + i, true) = (v & PAGE_TA) | f;
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}
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}
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}
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mm->pdp = MAX(mm->pdp, m);
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}
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