mirrors/cosmopolitan
1
0
Fork 0
mirror of https://github.com/jart/cosmopolitan.git synced 2025-06-28 07:18:30 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions 1

Don't relocate file descriptor memory

Browse source 
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.
This commit is contained in:
Justine Tunney 2022-09-09 16:54:28 -07:00
parent c3208eb9d5
commit 3265324e00
No known key found for this signature in database
GPG key ID: BE714B4575D6E328
35 changed files with 297 additions and 152 deletions
Download patch file Download diff file Expand all files Collapse all files

53
libc/intrin/directmap.c Normal file
View file

@ -0,0 +1,53 @@
/*-*- 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/strace.internal.h"
#include "libc/calls/syscall-sysv.internal.h"
#include "libc/errno.h"
#include "libc/intrin/describeflags.internal.h"
#include "libc/nt/runtime.h"
#include "libc/runtime/directmap.internal.h"
#include "libc/runtime/memtrack.internal.h"
/**
* Obtains memory mapping directly from system.
*
* The mmap() function needs to track memory mappings in order to
* support Windows NT and Address Sanitizer. That memory tracking can be
* bypassed by calling this function. However the caller is responsible
* for passing the magic memory handle on Windows NT to CloseHandle().
*
* @asyncsignalsafe
* @threadsafe
*/
struct DirectMap sys_mmap(void *addr, size_t size, int prot, int flags, int fd,
int64_t off) {
struct DirectMap d;
if (!IsWindows() && !IsMetal()) {
d.addr = __sys_mmap(addr, size, prot, flags, fd, off, off);
d.maphandle = kNtInvalidHandleValue;
} else if (IsMetal()) {
d = sys_mmap_metal(addr, size, prot, flags, fd, off);
} else {
d = sys_mmap_nt(addr, size, prot, flags, fd, off);
}
KERNTRACE("sys_mmap(%.12p%s, %'zu, %s, %s, %d, %'ld) → {%.12p, %p}% m", addr,
DescribeFrame((intptr_t)addr >> 16), size, DescribeProtFlags(prot),
DescribeMapFlags(flags), fd, off, d.addr, d.maphandle);
return d;
}