mirror of
https://github.com/jart/cosmopolitan.git
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425c055116
- Polyfill readlink("foo/") dir check on Windows
- Support asynchronous signal delivery on Windows
- Restore Windows Console from execve() daisy chain
- Work around bug in AARCH64 Optimized Routines memcmp()
- Disable unbourne.com shell completion on Windows for now
- Don't always set virtual terminal input state on console
- Remove Musl Libc's unusual preservation of realpath("//")
- Make realpath() strongly link malloc() to pass configure test
- Delete cosh.com shell, now that unbourne.com works on Windows!
69 lines
4 KiB
C
69 lines
4 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 2021 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/syscall-nt.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/describeflags.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/runtime.h"
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#include "libc/runtime/zipos.internal.h"
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#include "libc/sysv/errfuns.h"
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/**
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* Reads symbolic link.
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*
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* This does *not* nul-terminate the buffer.
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*
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* @param dirfd is normally AT_FDCWD but if it's an open directory and
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* file is a relative path, then file is opened relative to dirfd
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* @param path must be a symbolic link pathname
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* @param buf will receive symbolic link contents, and won't be modified
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* unless the function succeeds (with the exception of no-malloc nt)
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* and this buffer will *not* be nul-terminated
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* @return number of bytes written to buf, or -1 w/ errno; if the
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* return is equal to bufsiz then truncation may have occurred
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* @raise EINVAL if path isn't a symbolic link
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* @raise ENOENT if `path` didn't exist
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* @raise ENOTDIR if parent component existed that's not a directory
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* @raise ENOTDIR if base component ends with slash and is not a dir
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* @raise ENAMETOOLONG if symlink-resolved `path` length exceeds `PATH_MAX`
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* @raise ENAMETOOLONG if component in `path` exists longer than `NAME_MAX`
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* @raise EBADF on relative `path` when `dirfd` isn't open or `AT_FDCWD`
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* @raise ELOOP if a loop was detected resolving parent components
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* @asyncsignalsafe
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*/
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ssize_t readlinkat(int dirfd, const char *path, char *buf, size_t bufsiz) {
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ssize_t bytes;
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if ((bufsiz && !buf) || (IsAsan() && (!__asan_is_valid_str(path) ||
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!__asan_is_valid(buf, bufsiz)))) {
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bytes = efault();
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} else if (_weaken(__zipos_notat) &&
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(bytes = __zipos_notat(dirfd, path)) == -1) {
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STRACE("TODO: zipos support for readlinkat");
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} else if (!IsWindows()) {
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bytes = sys_readlinkat(dirfd, path, buf, bufsiz);
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} else {
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bytes = sys_readlinkat_nt(dirfd, path, buf, bufsiz);
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}
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STRACE("readlinkat(%s, %#s, [%#.*s]) → %d% m", DescribeDirfd(dirfd), path,
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(int)MAX(0, bytes), buf, bytes);
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return bytes;
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}
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