mirror of
https://github.com/jart/cosmopolitan.git
synced 2025-01-31 11:37:35 +00:00
3265324e00
This change fixes #496 where ASAN spotted a race condition that could happen in multithreaded programs, with more than OPEN_MAX descriptors when using ZipOS or Windows NT, which require tracking open file info and this change fixes that table so it never relocates, thus allowing us to continue to enjoy the benefits of avoiding locks while reading.
116 lines
5.5 KiB
C
116 lines
5.5 KiB
C
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
|
|
│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
|
|
╞══════════════════════════════════════════════════════════════════════════════╡
|
|
│ Copyright 2020 Justine Alexandra Roberts Tunney │
|
|
│ │
|
|
│ Permission to use, copy, modify, and/or distribute this software for │
|
|
│ any purpose with or without fee is hereby granted, provided that the │
|
|
│ above copyright notice and this permission notice appear in all copies. │
|
|
│ │
|
|
│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
|
|
│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
|
|
│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
|
|
│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
|
|
│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
|
|
│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
|
|
│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
|
|
│ PERFORMANCE OF THIS SOFTWARE. │
|
|
╚─────────────────────────────────────────────────────────────────────────────*/
|
|
#include "libc/calls/struct/sigset.h"
|
|
#include "libc/runtime/runtime.h"
|
|
#include "libc/runtime/symbols.internal.h"
|
|
|
|
/**
|
|
* Rewrites code in memory to hook function calls.
|
|
*
|
|
* We do this by searching each function for the nop instruction
|
|
* inserted by GCC when we use the -pg -mnop-mcount flags. There's no
|
|
* risk of corrupting data since the linker scripts won't mix code and
|
|
* data.
|
|
*
|
|
* Modules built with -O3 and without the profiling flags might have
|
|
* these same nop instructions, but that shouldn't be problematic since
|
|
* they're only there for the puposes of aligning jumps, and therefore
|
|
* aren't actually executed. However codebases that use huge function
|
|
* alignments with wide-nop slides could pose minor issues. Further note
|
|
* that Cosmopolitan sources are almost never intentionally written to
|
|
* use code alignment, since we've only seen a few cases where it helps.
|
|
*
|
|
* @see ape/ape.lds
|
|
*/
|
|
privileged noinstrument noasan int __hook(void *ifunc,
|
|
struct SymbolTable *symbols) {
|
|
int rc;
|
|
size_t i;
|
|
char *p, *pe;
|
|
intptr_t addr;
|
|
uint64_t code, mcode;
|
|
sigset_t mask, oldmask;
|
|
intptr_t kMcount = (intptr_t)&mcount;
|
|
intptr_t kProgramCodeStart = (intptr_t)_ereal;
|
|
intptr_t kPrivilegedStart = (intptr_t)__privileged_addr;
|
|
if (!symbols) return -1;
|
|
__morph_begin();
|
|
for (i = 0; i < symbols->count; ++i) {
|
|
if (symbols->addr_base + symbols->symbols[i].x < kProgramCodeStart) {
|
|
continue;
|
|
}
|
|
if (symbols->addr_base + symbols->symbols[i].y >= kPrivilegedStart) {
|
|
break;
|
|
}
|
|
for (p = (char *)symbols->addr_base + symbols->symbols[i].x,
|
|
pe = (char *)symbols->addr_base + symbols->symbols[i].y;
|
|
p + 8 - 1 <= pe; ++p) {
|
|
code = ((uint64_t)(255 & p[7]) << 070 | (uint64_t)(255 & p[6]) << 060 |
|
|
(uint64_t)(255 & p[5]) << 050 | (uint64_t)(255 & p[4]) << 040 |
|
|
(uint64_t)(255 & p[3]) << 030 | (uint64_t)(255 & p[2]) << 020 |
|
|
(uint64_t)(255 & p[1]) << 010 | (uint64_t)(255 & p[0]) << 000);
|
|
|
|
/*
|
|
* Test for -mrecord-mcount (w/ -fpie or -fpic)
|
|
*
|
|
* nopw 0x00(%rax,%rax,1) ← morphed by package.com
|
|
* call *mcount(%rip) ← linked w/o -static
|
|
* addr32 call mcount ← relaxed w/ -static
|
|
* addr32 call mcount ← relaxed w/ -static
|
|
*
|
|
* Note that gcc refuses to insert the six byte nop.
|
|
*/
|
|
if ((code & 0x0000FFFFFFFFFFFF) == 0x0000441F0F66 ||
|
|
(code & 0x0000FFFFFFFFFFFF) ==
|
|
((((kMcount - ((intptr_t)&p[2] + 4)) << 16) | 0xE867) &
|
|
0x0000FFFFFFFFFFFF) ||
|
|
(code & 0x0000FFFFFFFFFFFF) ==
|
|
((((kMcount - ((intptr_t)&p[2] + 4)) << 16) | 0xFF15) &
|
|
0x0000FFFFFFFFFFFF)) {
|
|
p[0] = 0x67;
|
|
p[1] = 0xE8;
|
|
addr = (intptr_t)ifunc - ((intptr_t)&p[2] + 4);
|
|
p[2] = (addr & 0x000000ff) >> 000;
|
|
p[3] = (addr & 0x0000ff00) >> 010;
|
|
p[4] = (addr & 0x00ff0000) >> 020;
|
|
p[5] = (addr & 0xff000000) >> 030;
|
|
break;
|
|
}
|
|
|
|
/*
|
|
* Test for -mnop-mcount (w/ -fno-pie)
|
|
*/
|
|
mcode = code & 0x000000FFFFFFFFFF;
|
|
if ((mcode == 0x00441F0F /* nopl 0x00(%eax,%eax,1) [canonical] */) ||
|
|
(mcode == 0x00041F0F67 /* nopl (%eax,%eax,1) [older gcc] */)) {
|
|
if (p[-1] != 0x66 /* nopw 0x0(%rax,%rax,1) [donotwant] */) {
|
|
p[0] = 0xE8 /* call Jvds */;
|
|
addr = (intptr_t)ifunc - ((intptr_t)&p[1] + 4);
|
|
p[1] = (addr & 0x000000ff) >> 000;
|
|
p[2] = (addr & 0x0000ff00) >> 010;
|
|
p[3] = (addr & 0x00ff0000) >> 020;
|
|
p[4] = (addr & 0xff000000) >> 030;
|
|
}
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
__morph_end();
|
|
return 0;
|
|
}
|