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https://github.com/jart/cosmopolitan.git
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1eb6484c9c
This change addresses a bug that was reported in #923 where bash on Windows behaved strangely. It turned out that our weak linking of malloc() caused bash's configure script to favor its own getcwd() function, which is implemented in the most astonishing way, using opendir() and readdir() to recursively construct the current path. This change moves getcwd() into LIBC_STDIO so it can strongly link malloc(). A new __getcwd() function is now introduced, so all the low-level runtime services can still use the actual system call. It provides the Linux Kernel API convention across platforms, and is overall a higher-quality implementation than what we had before. In the future, we should probably take a closer look into why bash's getcwd() polyfill wasn't working as intended on Windows, since there might be a potential opportunity there to improve our readdir() too.
77 lines
3.3 KiB
C
77 lines
3.3 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 2023 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/mem/mem.h"
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#include "libc/str/str.h"
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#include "libc/sysv/errfuns.h"
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/**
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* Returns current working directory, e.g.
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*
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* const char *dirname = gc(getcwd(0,0)); // if malloc is linked
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* const char *dirname = getcwd(alloca(PATH_MAX),PATH_MAX);
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*
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* @param buf is where UTF-8 NUL-terminated path string gets written,
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* which may be NULL to ask this function to malloc a buffer
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* @param size is number of bytes available in buf, e.g. PATH_MAX+1,
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* which may be 0 if buf is NULL
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* @return buf containing system-normative path or NULL w/ errno
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* @raise EACCES if the current directory path couldn't be accessed
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* @raise ERANGE if `size` wasn't big enough for path and nul byte
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* @raise ENOMEM on failure to allocate the requested buffer
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* @raise EINVAL if `size` is zero and `buf` is non-null
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* @raise EFAULT if `buf` points to invalid memory
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*/
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char *getcwd(char *buf, size_t size) {
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// setup memory per api
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char *path;
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if (buf) {
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path = buf;
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if (!size) {
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einval();
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return 0;
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}
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} else {
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if (!size) size = 4096;
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if (!(path = malloc(size))) {
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return 0; // enomem
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}
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}
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// invoke the real system call
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int got = __getcwd(path, size);
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if (got == -1) {
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if (path != buf) {
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free(path);
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}
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return 0; // eacces, erange, or efault
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}
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// cut allocation down to size
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if (path != buf) {
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char *p;
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if ((p = realloc(path, strlen(path) + 1))) {
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path = p;
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}
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}
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// return result
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return path;
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}
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