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110 lines
2.7 KiB
C
110 lines
2.7 KiB
C
/* membuf.c - A simple implementation of a dynamic buffer
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* Copyright (C) 2001, 2003 Free Software Foundation, Inc.
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*
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* This file is part of GnuPG.
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*
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* GnuPG is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* GnuPG is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
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* USA.
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*/
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#include <config.h>
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#include <stdlib.h>
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#include <errno.h>
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#include "membuf.h"
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#include "util.h"
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/* A simple implementation of a dynamic buffer. Use init_membuf() to
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create a buffer, put_membuf to append bytes and get_membuf to
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release and return the buffer. Allocation errors are detected but
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only returned at the final get_membuf(), this helps not to clutter
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the code with out of core checks. */
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void
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init_membuf (membuf_t *mb, int initiallen)
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{
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mb->len = 0;
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mb->size = initiallen;
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mb->out_of_core = 0;
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mb->buf = xtrymalloc (initiallen);
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if (!mb->buf)
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mb->out_of_core = errno;
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}
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/* Same as init_membuf but allocates the buffer in secure memory. */
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void
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init_membuf_secure (membuf_t *mb, int initiallen)
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{
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mb->len = 0;
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mb->size = initiallen;
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mb->out_of_core = 0;
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mb->buf = xtrymalloc (initiallen);
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if (!mb->buf)
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mb->out_of_core = errno;
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}
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void
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put_membuf (membuf_t *mb, const void *buf, size_t len)
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{
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if (mb->out_of_core)
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return;
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if (mb->len + len >= mb->size)
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{
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char *p;
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mb->size += len + 1024;
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p = xtryrealloc (mb->buf, mb->size);
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if (!p)
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{
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mb->out_of_core = errno ? errno : ENOMEM;
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/* Wipe out what we already accumulated. This is required
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in case we are storing sensitive data here. The membuf
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API does not provide another way to cleanup after an
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error. */
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memset (mb->buf, 0, mb->len);
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return;
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}
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mb->buf = p;
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}
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memcpy (mb->buf + mb->len, buf, len);
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mb->len += len;
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}
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void *
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get_membuf (membuf_t *mb, size_t *len)
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{
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char *p;
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if (mb->out_of_core)
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{
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xfree (mb->buf);
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mb->buf = NULL;
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errno = mb->out_of_core;
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return NULL;
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}
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p = mb->buf;
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if (len)
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*len = mb->len;
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mb->buf = NULL;
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mb->out_of_core = ENOMEM; /* hack to make sure it won't get reused. */
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return p;
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}
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