15aa00d597
not based on gpl'ed code, just prototype and usage. I'm not 100% certain they behave the same while the system is in trouble (eg: malloc() failing) but in those circumstances all bets would be off anyway. These routines work like sprintf() and vsprintf(), except that instead of using a fixed buffer, they allocate memory and return it to the user and it's the user's responsibility to free() it. They have allocate as much memory as they need (and can get), so the size of strings it can deal with is limited only by the amount of memory it can malloc() on your behalf. There are a few gpl'ed programs starting to use this interface, and it's becoming more common with the scares about security risks with sprintf(). I dont like the look of the code that the various programs (including cvs, gdb, libg++, etc) provide if configure can't find it on the system. It should be possible to modify the stdio core code to provide this interface more efficiently, I was more worried about having something that worked and was secure. :-) (I noticed that there was once intended to be a smprintf() routine when our stdio was written for 4.4BSD, but it looks pretty stillborn, and it's intended interface is not clear). Since Linux and gnu libc have this interface, it seemed silly to bring yet another one onto the scene.
109 lines
2.8 KiB
C
109 lines
2.8 KiB
C
/*-
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* Copyright (c) 1996 Peter Wemm <peter@freebsd.org>
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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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#if defined(LIBC_RCS) && !defined(lint)
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static char rcsid[] = "$Id$";
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#endif /* LIBC_RCS and not lint */
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#include <stdio.h>
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#include <stdlib.h>
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#if __STDC__
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#include <stdarg.h>
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#else
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#include <varargs.h>
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#endif
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#define CHUNK_SPARE 128 /* how much spare to allocate to avoid realloc calls */
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struct bufcookie {
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char *base; /* start of buffer */
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int size;
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int left;
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};
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static int
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writehook(cookie, buf, len)
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void *cookie;
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char *buf;
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int len;
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{
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struct bufcookie *h = (struct bufcookie *)cookie;
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if (len == 0)
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return 0;
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if (len > h->left) {
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/* grow malloc region */
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h->left = h->left + len + CHUNK_SPARE;
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h->size = h->size + len + CHUNK_SPARE;
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h->base = realloc(h->base, h->size);
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if (h->base == NULL)
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return (-1);
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}
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/* "write" it */
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(void)memcpy(h->base + h->size - h->left, buf, len);
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h->left -= len;
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return (0);
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}
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int
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vasprintf(str, fmt, ap)
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char **str;
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const char *fmt;
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va_list ap;
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{
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int ret;
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FILE *f;
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struct bufcookie h;
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h.base = malloc(CHUNK_SPARE);
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if (h.base == NULL)
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return (-1);
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h.size = CHUNK_SPARE;
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h.left = CHUNK_SPARE;
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f = funopen(&h, NULL, writehook, NULL, NULL);
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if (f == NULL) {
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free(h.base);
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return (-1);
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}
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ret = vfprintf(f, fmt, ap);
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fclose(f);
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if (ret < 0) {
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free(h.base);
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return (-1);
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}
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if (h.base == NULL) /* failed to realloc in writehook */
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return (-1);
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h.base[h.size - h.left] = '\0';
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*str = realloc(h.base, h.size - h.left + 1);
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if (*str == NULL) /* failed to realloc it to actual size */
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return -1;
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return (ret);
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}
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