130 lines
3.4 KiB
C
130 lines
3.4 KiB
C
/* $NetBSD: expandm.c,v 1.12 2019/01/24 22:07:14 mrg Exp $ */
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/*-
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* Copyright (c) 2019 The NetBSD Foundation, Inc.
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* All rights reserved.
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*
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* This code is derived from software contributed to The NetBSD Foundation
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* by Christos Zoulas.
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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 NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__RCSID("$NetBSD: expandm.c,v 1.12 2019/01/24 22:07:14 mrg Exp $");
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#include <limits.h>
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#include <stdio.h>
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#include <string.h>
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#include <stdlib.h>
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#include <errno.h>
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#include "expandm.h"
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#ifdef TEST
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#undef INT_MAX
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#define INT_MAX 31
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#endif
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const char * __attribute__((__format_arg__(1)))
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expandm(const char *fmt, const char *sf, char **rbuf)
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{
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const int err = errno;
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const char *e = NULL;
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char *buf, *m, *nbuf;
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const char *ptr;
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buf = NULL;
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for (ptr = fmt; (m = strstr(ptr, "%m")) != NULL; ptr = m + 2) {
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size_t cnt = 0;
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size_t nlen;
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for (char *p = m; p >= ptr && *p == '%'; p--)
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cnt++;
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nlen = (size_t)(m - ptr);
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/*
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* we can't exceed INT_MAX because int is used as
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* a format width
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*/
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if (__predict_false(nlen >= INT_MAX)) {
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size_t blen = buf ? strlen(buf) : 0;
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size_t tlen;
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/*
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* if we would overflow a ptrdiff_t when computing
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* tlen, then don't bother. The format string is
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* simply too large to be converted.
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*/
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if (blen >= PTRDIFF_MAX ||
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nlen >= PTRDIFF_MAX - blen ||
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nlen >= SIZE_T_MAX - blen)
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goto out;
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tlen = nlen + blen;
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nbuf = realloc(buf, tlen + 1);
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if (nbuf == NULL)
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goto out;
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memcpy(nbuf + blen, ptr, nlen);
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nbuf[tlen] = '\0';
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ptr += nlen;
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buf = nbuf;
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}
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if (__predict_true(e == NULL && (cnt & 1) != 0))
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e = strerror(err);
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if (asprintf(&nbuf, "%s%.*s%s", buf ? buf : "",
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(int)(m - ptr), ptr, (cnt & 1) ? e : "%m") == -1)
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goto out;
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free(buf);
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buf = nbuf;
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}
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if (asprintf(&nbuf, "%s%s%s", buf ? buf : "", ptr, sf ? sf : "") == -1)
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goto out;
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free(buf);
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if (rbuf)
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*rbuf = nbuf;
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errno = err;
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return nbuf;
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out:
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free(buf);
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if (rbuf)
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*rbuf = NULL;
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errno = err;
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return fmt;
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}
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#ifdef TEST
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int
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main(int argc, char *argv[])
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{
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errno = ERANGE;
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printf("%s\n", expandm(argc > 1 ? argv[1] : "Message %%m=%m: %%%m%%",
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"...", NULL));
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return 0;
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}
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#endif
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