mirror of
https://github.com/jart/cosmopolitan.git
synced 2025-02-07 23:13:34 +00:00
119 lines
4.4 KiB
C
119 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 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 "ape/sections.internal.h"
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#include "libc/calls/calls.h"
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#include "libc/elf/def.h"
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#include "libc/elf/elf.h"
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#include "libc/elf/struct/ehdr.h"
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#include "libc/elf/struct/sym.h"
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#include "libc/errno.h"
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#include "libc/intrin/bits.h"
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#include "libc/macros.internal.h"
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#include "libc/runtime/runtime.h"
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#include "libc/runtime/symbols.internal.h"
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#include "libc/str/str.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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static bool GetElfSymbolValue(const Elf64_Ehdr *ehdr, size_t esize,
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const char *name, uint64_t *res) {
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Elf64_Xword i, n;
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const char *stab;
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const Elf64_Sym *st;
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if ((stab = GetElfStringTable(ehdr, esize)) &&
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(st = GetElfSymbolTable(ehdr, esize, &n))) {
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for (i = 0; i < n; ++i) {
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if (!strcmp(stab + st[i].st_name, name)) {
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*res = st[i].st_value;
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return true;
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}
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}
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}
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return false;
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}
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static bool IsMyDebugBinaryImpl(const char *path) {
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int fd;
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void *map;
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int64_t size;
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uintptr_t value;
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bool res = false;
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if ((fd = open(path, O_RDONLY | O_CLOEXEC, 0)) != -1) {
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// sanity test that this .com.dbg file (1) is an elf image, and (2)
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// contains the same number of bytes of code as our .com executable
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// which is currently running in memory.
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if ((size = lseek(fd, 0, SEEK_END)) != -1 &&
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(map = mmap(0, size, PROT_READ, MAP_SHARED, fd, 0)) != MAP_FAILED) {
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if (IsElf64Binary(map, size) &&
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GetElfSymbolValue(map, size, "_etext", &value)) {
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res = !_etext || value == (uintptr_t)_etext;
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}
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munmap(map, size);
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}
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close(fd);
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}
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return res;
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}
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static bool IsMyDebugBinary(const char *path) {
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int e;
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bool res;
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e = errno;
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res = IsMyDebugBinaryImpl(path);
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errno = e;
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return res;
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}
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/**
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* Returns path of binary with the debug information, or null.
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*
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* @return path to debug binary, or NULL
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*/
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const char *FindDebugBinary(void) {
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static bool once;
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static char *res;
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static char buf[PATH_MAX];
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char *p;
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size_t n;
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if (!once) {
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p = GetProgramExecutableName();
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n = strlen(p);
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if ((n > 4 && READ32LE(p + n - 4) == READ32LE(".dbg")) ||
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IsMyDebugBinary(p)) {
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res = p;
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} else if (n > 4 && READ32LE(p + n - 4) == READ32LE(".com") &&
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n + 4 < ARRAYLEN(buf)) {
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mempcpy(mempcpy(buf, p, n), ".dbg", 5);
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if (IsMyDebugBinary(buf)) {
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res = buf;
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}
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} else if (n + 8 < ARRAYLEN(buf)) {
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mempcpy(mempcpy(buf, p, n), ".com.dbg", 9);
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if (IsMyDebugBinary(buf)) {
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res = buf;
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}
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}
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if (!res) {
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res = getenv("COMDBG");
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}
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once = true;
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}
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return res;
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}
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