busybox/libbb/simplify_path.c

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/* vi: set sw=4 ts=4: */
/*
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* bb_simplify_path implementation for busybox
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*
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* Copyright (C) 2001 Manuel Novoa III <mjn3@codepoet.org>
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*
* Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
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*/
#include "libbb.h"
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char *bb_simplify_path(const char *path)
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{
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char *s, *start, *p;
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if (path[0] == '/')
start = xstrdup(path);
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else {
s = xrealloc_getcwd_or_warn(NULL);
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start = concat_path_file(s, path);
free(s);
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}
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p = s = start;
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do {
if (*p == '/') {
if (*s == '/') { /* skip duplicate (or initial) slash */
continue;
} else if (*s == '.') {
if (s[1] == '/' || s[1] == 0) { /* remove extra '.' */
continue;
} else if ((s[1] == '.') && (s[2] == '/' || s[2] == 0)) {
++s;
if (p > start) {
while (*--p != '/'); /* omit previous dir */
}
continue;
}
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}
}
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*++p = *s;
} while (*++s);
if ((p == start) || (*p != '/')) { /* not a trailing slash */
++p; /* so keep last character */
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}
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*p = 0;
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return start;
}