Blame src/util/tpax_path_copy.c

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/**************************************************************/
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/*  tpax: a topological pax implementation                    */
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/*  Copyright (C) 2020--2024  SysDeer Technologies, LLC       */
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/*  Released under GPLv2 and GPLv3; see COPYING.TPAX.         */
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/**************************************************************/
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#include <stdint.h>
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#include <stdlib.h>
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#include <string.h>
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#include <errno.h>
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#include <sys/stat.h>
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#include <tpax/tpax.h>
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#include "tpax_driver_impl.h"
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int tpax_util_path_copy(
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	char *          dstpath,
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	const char *    srcpath,
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	size_t          bufsize,
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	uint32_t        flags,
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	size_t *        nwritten)
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{
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	const char *    src;
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	char *          dst;
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	char *          cap;
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	if (!bufsize) {
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		errno = ENOBUFS;
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		return -1;
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	}
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	src = srcpath;
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	dst = dstpath;
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	cap = &dst[bufsize];
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	if ((src[0] == '/') && (src[1] == '/') && (src[2] != '/')) {
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		*dst++ = *src++;
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		*dst++ = *src++;
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	}
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	if (flags & TPAX_DRIVER_PURE_PATH_OUTPUT)
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		if ((src[0] == '.') && (src[1] == '/'))
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			for (++src; *src=='/'; src++)
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				(void)0;
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	for (; *src; ) {
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		if ((src[0] == '.') && (src[1] == '.')) {
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			if ((src[2] == '/') || (src[2] == '\0')) {
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				if (flags & TPAX_DRIVER_STRICT_PATH_INPUT) {
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					errno = EINVAL;
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					return -1;
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				}
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			}
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		}
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		if (flags & TPAX_DRIVER_PURE_PATH_OUTPUT) {
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			if ((src[0] == '.') && (src[1] == '/') && (src[-1] == '/')) {
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				for (++src; *src=='/'; src++)
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					(void)0;
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			} else if ((src[0] == '/')) {
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				for (src++; *src=='/'; src++)
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					(void)0;
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				*dst++ = '/';
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			} else {
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				*dst++ = *src++;
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			}
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		} else {
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			*dst++ = *src++;
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		}
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		if (dst == cap) {
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			errno = ENOBUFS;
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			return -1;
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		}
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	}
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	if (nwritten)
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		*nwritten = dst - dstpath;
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	*dst = '\0';
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	return 0;
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}