e2f6816100
Now that we've updated the prototypes of the basename(3) and dirname(3) functions to conform to POSIX, let's go ahead and reimplement dirname(3) in such a way that it's thread-safe, but also guaranteed to succeed. C libraries like glibc, musl and the one that's part of Solaris already follow such an approach. Move the existing implementation to another source file, freebsd11_dirname.c to keep existing users of the API that pass in a constant string happy, using symbol versioning. Put a new version of the function in dirname.c, obtained from CloudABI's C library. This version scans through the pathname string from left to right, normalizing it, while discarding the last pathname component. Reviewed by: emaste, jilles Differential Revision: https://reviews.freebsd.org/D7355
91 lines
2.6 KiB
C
91 lines
2.6 KiB
C
/*-
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* Copyright (c) 2015-2016 Nuxi, https://nuxi.nl/
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <libgen.h>
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#include <stdbool.h>
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#include <string.h>
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char *
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dirname(char *path)
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{
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const char *in, *prev, *begin, *end;
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char *out;
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size_t prevlen;
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bool skipslash;
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/*
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* If path is a null pointer or points to an empty string,
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* dirname() shall return a pointer to the string ".".
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*/
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if (path == NULL || *path == '\0')
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return ((char *)".");
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/* Retain at least one leading slash character. */
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in = out = *path == '/' ? path + 1 : path;
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skipslash = true;
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prev = ".";
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prevlen = 1;
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for (;;) {
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/* Extract the next pathname component. */
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while (*in == '/')
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++in;
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begin = in;
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while (*in != '/' && *in != '\0')
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++in;
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end = in;
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if (begin == end)
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break;
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/*
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* Copy over the previous pathname component, except if
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* it's dot. There is no point in retaining those.
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*/
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if (prevlen != 1 || *prev != '.') {
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if (!skipslash)
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*out++ = '/';
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skipslash = false;
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memmove(out, prev, prevlen);
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out += prevlen;
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}
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/* Preserve the pathname component for the next iteration. */
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prev = begin;
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prevlen = end - begin;
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}
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/*
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* If path does not contain a '/', then dirname() shall return a
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* pointer to the string ".".
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*/
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if (out == path)
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*out++ = '.';
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*out = '\0';
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return (path);
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}
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