mirror of
https://github.com/jart/cosmopolitan.git
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1d8937d528
This change reduces the memory requirements of your APE Loader by 10x, in terms of virtual memory size, thanks to the help of alloca(). We're also now creating argument blocks with the same layout across systems.
93 lines
4.6 KiB
C
93 lines
4.6 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 "libc/calls/calls.h"
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#include "libc/calls/cp.internal.h"
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#include "libc/calls/internal.h"
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#include "libc/calls/struct/iovec.h"
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#include "libc/calls/struct/iovec.internal.h"
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#include "libc/calls/syscall-sysv.internal.h"
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#include "libc/dce.h"
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#include "libc/intrin/asan.internal.h"
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#include "libc/intrin/strace.internal.h"
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#include "libc/intrin/weaken.h"
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#include "libc/runtime/zipos.internal.h"
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#include "libc/sock/internal.h"
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#include "libc/sock/sock.h"
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#include "libc/sysv/errfuns.h"
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/**
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* Reads data from file descriptor.
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*
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* This function changes the current file position. For documentation
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* on file position behaviors and gotchas, see the lseek() function.
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* This function may be used on socket file descriptors, including on
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* Windows.
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*
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* @param fd is something open()'d earlier
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* @param buf is copied into, cf. copy_file_range(), sendfile(), etc.
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* @param size in range [1..0x7ffff000] is reasonable
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* @return [1..size] bytes on success, 0 on EOF, or -1 w/ errno; with
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* exception of size==0, in which case return zero means no error
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* @raise EBADF if `fd` is negative or not an open file descriptor
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* @raise EBADF if `fd` is open in `O_WRONLY` mode
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* @raise EFAULT if `size` is nonzero and `buf` points to bad memory
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* @raise EPERM if pledge() is in play without the stdio promise
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* @raise EIO if low-level i/o error happened
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* @raise EINTR if signal was delivered instead
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* @raise ECANCELED if thread was cancelled in masked mode
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* @raise ENOTCONN if `fd` is a socket and it isn't connected
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* @raise ECONNRESET if socket peer forcibly closed connection
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* @raise ETIMEDOUT if socket transmission timeout occurred
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* @raise EAGAIN if `O_NONBLOCK` is in play and read needs to block,
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* or `SO_RCVTIMEO` is in play and the time interval elapsed
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* @raise ENOBUFS is specified by POSIX
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* @raise ENXIO is specified by POSIX
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* @cancellationpoint
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* @asyncsignalsafe
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* @restartable
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* @vforksafe
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*/
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ssize_t read(int fd, void *buf, size_t size) {
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ssize_t rc;
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BEGIN_CANCELLATION_POINT;
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if (fd >= 0) {
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if ((!buf && size) || (IsAsan() && !__asan_is_valid(buf, size))) {
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rc = efault();
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} else if (fd < g_fds.n && g_fds.p[fd].kind == kFdZip) {
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rc = _weaken(__zipos_read)(
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(struct ZiposHandle *)(intptr_t)g_fds.p[fd].handle,
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&(struct iovec){buf, size}, 1, -1);
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} else if (!IsWindows() && !IsMetal()) {
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rc = sys_read(fd, buf, size);
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} else if (fd >= g_fds.n) {
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rc = ebadf();
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} else if (IsMetal()) {
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rc = sys_readv_metal(g_fds.p + fd, &(struct iovec){buf, size}, 1);
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} else {
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rc = sys_readv_nt(g_fds.p + fd, &(struct iovec){buf, size}, 1);
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}
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} else {
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rc = ebadf();
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}
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END_CANCELLATION_POINT;
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DATATRACE("read(%d, [%#.*hhs%s], %'zu) → %'zd% m", fd,
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(int)MAX(0, MIN(40, rc)), buf, rc > 40 ? "..." : "", size, rc);
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return rc;
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}
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