mirror of
https://github.com/jart/cosmopolitan.git
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d7c79f43ef
- Found some bugs in LLVM compiler-rt library - The useless LIBC_STUBS package is now deleted - Improve the overflow checking story even further - Get chibicc tests working in MODE=dbg mode again - The libc/isystem/ headers now have correctly named guards
51 lines
2.7 KiB
C
51 lines
2.7 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 2022 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/macros.internal.h"
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#include "libc/runtime/runtime.h"
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/**
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* Copies data between file descriptors the old fashioned way.
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*
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* This function is intended for simple programs without signals. If
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* signals are in play, then `SA_RESTART` needs to be used.
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*
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* @param in is input file descriptor
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* @param out is input file descriptor
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* @param n is number of bytes to exchange, or -1 for until eof
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* @return bytes successfully exchanged, or -1 w/ errno
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*/
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ssize_t copyfd(int in, int out, size_t n) {
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size_t i;
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char buf[512];
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ssize_t dr, dw;
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for (i = 0; i < n; i += dr) {
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dr = read(in, buf, MIN(n - i, sizeof(buf)));
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if (dr == -1) return -1;
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if (!dr) break;
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dw = write(out, buf, dr);
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if (dw == -1) return -1;
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if (dw != dr) {
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// POSIX requires atomic IO up to PIPE_BUF
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// The minimum permissible PIPE_BUF is 512
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abort();
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}
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}
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return i;
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}
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