mirror of
https://github.com/jart/cosmopolitan.git
synced 2025-01-31 19:43:32 +00:00
e466dd0553
This change hardens the code for opening /zip/ files using the system call interface. Thread safety and signal safety has been improved for file descriptors in general. We now document fixed addresses that are needed for low level allocations.
88 lines
4 KiB
C
88 lines
4 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/assert.h"
|
|
#include "libc/bits/weaken.h"
|
|
#include "libc/calls/calls.h"
|
|
#include "libc/calls/internal.h"
|
|
#include "libc/calls/state.internal.h"
|
|
#include "libc/calls/strace.internal.h"
|
|
#include "libc/calls/syscall-nt.internal.h"
|
|
#include "libc/calls/syscall-sysv.internal.h"
|
|
#include "libc/intrin/spinlock.h"
|
|
#include "libc/sock/syscall_fd.internal.h"
|
|
#include "libc/sysv/errfuns.h"
|
|
#include "libc/zipos/zipos.internal.h"
|
|
|
|
/**
|
|
* Closes file descriptor.
|
|
*
|
|
* This function may be used for file descriptors returned by socket,
|
|
* accept, epoll_create, and zipos file descriptors too.
|
|
*
|
|
* This function should never be called twice for the same file
|
|
* descriptor, regardless of whether or not an error happened. However
|
|
* that doesn't mean the error should be ignored.
|
|
*
|
|
* @return 0 on success, or -1 w/ errno
|
|
* @error EINTR means a signal was received while closing in which case
|
|
* close() does not need to be called again, since the fd will close
|
|
* in the background
|
|
* @asyncsignalsafe
|
|
* @vforksafe
|
|
*/
|
|
int close(int fd) {
|
|
int rc;
|
|
if (fd == -1) {
|
|
rc = 0;
|
|
} else if (fd < 0) {
|
|
rc = einval();
|
|
} else {
|
|
// for performance reasons we want to avoid holding __fds_lock()
|
|
// while sys_close() is happening. this leaves the kernel / libc
|
|
// having a temporarily inconsistent state. routines that obtain
|
|
// file descriptors the way __zipos_open() does need to retry if
|
|
// there's indication this race condition happened.
|
|
if (__isfdkind(fd, kFdZip)) {
|
|
rc = weaken(__zipos_close)(fd);
|
|
} else {
|
|
if (!IsWindows() && !IsMetal()) {
|
|
rc = sys_close(fd);
|
|
} else if (IsMetal()) {
|
|
rc = 0;
|
|
} else {
|
|
if (__isfdkind(fd, kFdEpoll)) {
|
|
rc = weaken(sys_close_epoll_nt)(fd);
|
|
} else if (__isfdkind(fd, kFdSocket)) {
|
|
rc = weaken(sys_closesocket_nt)(g_fds.p + fd);
|
|
} else if (__isfdkind(fd, kFdFile) || //
|
|
__isfdkind(fd, kFdConsole) || //
|
|
__isfdkind(fd, kFdProcess)) { //
|
|
rc = sys_close_nt(g_fds.p + fd);
|
|
} else {
|
|
rc = eio();
|
|
}
|
|
}
|
|
}
|
|
if (!__vforked) {
|
|
__releasefd(fd);
|
|
}
|
|
}
|
|
STRACE("%s(%d) → %d% m", "close", fd, rc);
|
|
return rc;
|
|
}
|