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gnupg/assuan/assuan-inquire.c

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/* assuan-inquire.c - handle inquire stuff
* Copyright (C) 2001, 2002 Free Software Foundation, Inc.
*
* This file is part of GnuPG.
*
* GnuPG is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* GnuPG is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
*/
#include <config.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include "assuan-defs.h"
#define digitp(a) ((a) >= '0' && (a) <= '9')
#define xtoi_1(p) (*(p) <= '9'? (*(p)- '0'): \
*(p) <= 'F'? (*(p)-'A'+10):(*(p)-'a'+10))
#define xtoi_2(p) ((xtoi_1(p) * 16) + xtoi_1((p)+1))
struct membuf {
size_t len;
size_t size;
char *buf;
int out_of_core;
int too_large;
size_t maxlen;
};
/* A simple implemnation of a dynamic buffer. Use init_membuf() to
create a buffer, put_membuf to append bytes and get_membuf to
release and return the buffer. Allocation errors are detected but
only returned at the final get_membuf(), this helps not to clutter
the code with out of core checks. */
static void
init_membuf (struct membuf *mb, int initiallen, size_t maxlen)
{
mb->len = 0;
mb->size = initiallen;
mb->out_of_core = 0;
mb->too_large = 0;
mb->maxlen = maxlen;
/* we need to allocate one byte more for get_membuf */
mb->buf = xtrymalloc (initiallen+1);
if (!mb->buf)
mb->out_of_core = 1;
}
static void
put_membuf (struct membuf *mb, const void *buf, size_t len)
{
if (mb->out_of_core || mb->too_large)
return;
if (mb->maxlen && mb->len + len > mb->maxlen)
{
mb->too_large = 1;
return;
}
if (mb->len + len >= mb->size)
{
char *p;
mb->size += len + 1024;
/* we need to allocate one byte more for get_membuf */
p = xtryrealloc (mb->buf, mb->size+1);
if (!p)
{
mb->out_of_core = 1;
return;
}
mb->buf = p;
}
memcpy (mb->buf + mb->len, buf, len);
mb->len += len;
}
static void *
get_membuf (struct membuf *mb, size_t *len)
{
char *p;
if (mb->out_of_core || mb->too_large)
{
xfree (mb->buf);
mb->buf = NULL;
return NULL;
}
mb->buf[mb->len] = 0; /* there is enough space for the hidden eos */
p = mb->buf;
*len = mb->len;
mb->buf = NULL;
mb->out_of_core = 1; /* don't allow a reuse */
return p;
}
static void
free_membuf (struct membuf *mb)
{
xfree (mb->buf);
mb->buf = NULL;
}
/**
* assuan_inquire:
* @ctx: An assuan context
* @keyword: The keyword used for the inquire
* @r_buffer: Returns an allocated buffer
* @r_length: Returns the length of this buffer
* @maxlen: If not 0, the size limit of the inquired data.
*
* A Server may use this to Send an inquire. r_buffer, r_length and
* maxlen may all be NULL/0 to indicate that no real data is expected.
*
* Return value: 0 on success or an ASSUAN error code
**/
AssuanError
assuan_inquire (ASSUAN_CONTEXT ctx, const char *keyword,
char **r_buffer, size_t *r_length, size_t maxlen)
{
AssuanError rc;
struct membuf mb;
char cmdbuf[100];
unsigned char *line, *p;
int linelen;
int nodataexpected;
if (!ctx || !keyword || (10 + strlen (keyword) >= sizeof (cmdbuf)))
return ASSUAN_Invalid_Value;
nodataexpected = !r_buffer && !r_length && !maxlen;
if (!nodataexpected && (!r_buffer || !r_length))
return ASSUAN_Invalid_Value;
if (!ctx->is_server)
return ASSUAN_Not_A_Server;
if (ctx->in_inquire)
return ASSUAN_Nested_Commands;
ctx->in_inquire = 1;
if (nodataexpected)
memset (&mb, 0, sizeof mb); /* avoid compiler warnings */
else
init_membuf (&mb, maxlen? maxlen:1024, maxlen);
strcpy (stpcpy (cmdbuf, "INQUIRE "), keyword);
rc = assuan_write_line (ctx, cmdbuf);
if (rc)
goto leave;
for (;;)
{
do
{
rc = _assuan_read_line (ctx);
if (rc)
goto leave;
line = ctx->inbound.line;
linelen = ctx->inbound.linelen;
}
while (*line == '#' || !linelen);
if (line[0] == 'E' && line[1] == 'N' && line[2] == 'D'
&& (!line[3] || line[3] == ' '))
break; /* END command received*/
if (line[0] == 'C' && line[1] == 'A' && line[2] == 'N')
{
rc = ASSUAN_Canceled;
goto leave;
}
if (line[0] != 'D' || line[1] != ' ' || nodataexpected)
{
rc = ASSUAN_Unexpected_Command;
goto leave;
}
if (linelen < 3)
continue;
line += 2;
linelen -= 2;
p = line;
while (linelen)
{
for (;linelen && *p != '%'; linelen--, p++)
;
put_membuf (&mb, line, p-line);
if (linelen > 2)
{ /* handle escaping */
unsigned char tmp[1];
p++;
*tmp = xtoi_2 (p);
p += 2;
linelen -= 3;
put_membuf (&mb, tmp, 1);
}
line = p;
}
if (mb.too_large)
{
rc = ASSUAN_Too_Much_Data;
goto leave;
}
}
if (!nodataexpected)
{
*r_buffer = get_membuf (&mb, r_length);
if (!*r_buffer)
rc = ASSUAN_Out_Of_Core;
}
leave:
if (!nodataexpected)
free_membuf (&mb);
ctx->in_inquire = 0;
return rc;
}