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gnupg/util/iobuf.c

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/* iobuf.c - file handling
* Copyright (C) 1998 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 <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <assert.h>
#include <sys/stat.h>
#include <unistd.h>
#include "memory.h"
#include "util.h"
#include "iobuf.h"
typedef struct {
FILE *fp; /* open file handle */
char fname[1]; /* name of the file */
} file_filter_ctx_t ;
typedef struct {
int usage;
size_t size;
size_t count;
int partial; /* 1 = partial header, 2 in last partial packet */
int eof;
} block_filter_ctx_t;
static int underflow(IOBUF a);
/****************
* Read data from a file into buf which has an allocated length of *LEN.
* return the number of read bytes in *LEN. OPAQUE is the FILE * of
* the stream. A is not used.
* control maybe:
* IOBUFCTRL_INIT: called just before the function is linked into the
* list of function. This can be used to prepare internal
* data structures of the function.
* IOBUFCTRL_FREE: called just before the function is removed from the
* list of functions and can be used to release internal
* data structures or close a file etc.
* IOBUFCTRL_UNDERFLOW: called by iobuf_underflow to fill the buffer
* with new stuff. *RET_LEN is the available size of the
* buffer, and should be set to the number of bytes
* which were put into the buffer. The function
* returns 0 to indicate success, -1 on EOF and
* G10ERR_xxxxx for other errors.
*
* IOBUFCTRL_FLUSH: called by iobuf_flush() to write out the collected stuff.
* *RET_LAN is the number of bytes in BUF.
*
*/
static int
file_filter(void *opaque, int control, IOBUF chain, byte *buf, size_t *ret_len)
{
file_filter_ctx_t *a = opaque;
FILE *fp = a->fp;
size_t size = *ret_len;
size_t nbytes = 0;
int c, rc = 0;
char *p;
if( control == IOBUFCTRL_UNDERFLOW ) {
assert( size ); /* need a buffer */
for(; size; size-- ) {
if( (c=getc(fp)) == EOF ) {
if( ferror(fp) ) {
log_error("%s: read error: %s\n",
a->fname, strerror(errno));
rc = G10ERR_READ_FILE;
}
else if( !nbytes )
rc = -1; /* okay: we can return EOF now. */
break;
}
buf[nbytes++] = c & 0xff;
}
*ret_len = nbytes;
}
else if( control == IOBUFCTRL_FLUSH ) {
for(p=buf; nbytes < size; nbytes++, p++ ) {
if( putc(*p, fp) == EOF ) {
log_error("%s: write error: %s\n",
a->fname, strerror(errno));
rc = G10ERR_WRITE_FILE;
break;
}
}
*ret_len = nbytes;
}
else if( control == IOBUFCTRL_INIT ) {
}
else if( control == IOBUFCTRL_DESC ) {
*(char**)buf = "file_filter";
}
else if( control == IOBUFCTRL_FREE ) {
if( fp != stdin && fp != stdout )
fclose(fp);
fp = NULL;
m_free(a); /* we can free our context now */
}
return rc;
}
/****************
* This is used to implement the block write mode.
* Block reading is done on a byte by byte basis in readbyte(),
* without a filter
*/
static int
block_filter(void *opaque, int control, IOBUF chain, byte *buf, size_t *ret_len)
{
block_filter_ctx_t *a = opaque;
size_t size = *ret_len;
int c, rc = 0;
char *p;
if( control == IOBUFCTRL_UNDERFLOW ) {
size_t n=0;
p = buf;
assert( size ); /* need a buffer */
if( a->eof ) /* don't read any further */
rc = -1;
while( !rc && size ) {
if( !a->size ) { /* get the length bytes */
if( a->partial == 2 ) {
a->eof = 1;
if( !n )
rc = -1;
break;
}
else if( a->partial ) {
if( (c = iobuf_get(chain)) == -1 ) {
log_error("block_filter: 1st length byte missing\n");
rc = G10ERR_READ_FILE;
break;
}
if( c < 192 ) {
a->size = c;
a->partial = 2;
if( !a->size ) {
a->eof = 1;
if( !n )
rc = -1;
break;
}
}
else if( c < 224 ) {
a->size = (c - 192) * 256;
if( (c = iobuf_get(chain)) == -1 ) {
log_error("block_filter: 2nd length byte missing\n");
rc = G10ERR_READ_FILE;
break;
}
a->size += c + 192;
a->partial = 2;
if( !a->size ) {
a->eof = 1;
if( !n )
rc = -1;
break;
}
}
else { /* next partial body length */
a->size = 1 << (c & 0x1f);
}
}
else {
c = iobuf_get(chain);
a->size = c << 8;
c = iobuf_get(chain);
a->size |= c;
if( c == -1 ) {
log_error("block_filter: error reading length info\n");
rc = G10ERR_READ_FILE;
}
if( !a->size ) {
a->eof = 1;
if( !n )
rc = -1;
break;
}
}
}
for(; !rc && size && a->size; size--, a->size-- ) {
if( (c=iobuf_get(chain)) == -1 ) {
log_error("block_filter %p: read error (size=%lu,a->size=%lu)\n",
a, (ulong)size, (ulong)a->size);
rc = G10ERR_READ_FILE;
}
else {
*p++ = c;
n++;
}
}
}
*ret_len = n;
}
else if( control == IOBUFCTRL_FLUSH ) {
size_t avail, n;
assert( !a->partial );
for(p=buf; !rc && size; ) {
n = size;
avail = a->size - a->count;
if( !avail ) {
if( n > a->size ) {
iobuf_put( chain, (a->size >> 8) & 0xff );
iobuf_put( chain, a->size & 0xff );
avail = a->size;
a->count = 0;
}
else {
iobuf_put( chain, (n >> 8) & 0xff );
iobuf_put( chain, n & 0xff );
avail = n;
a->count = a->size - n;
}
}
if( n > avail )
n = avail;
if( iobuf_write(chain, p, n ) )
rc = G10ERR_WRITE_FILE;
a->count += n;
p += n;
size -= n;
}
}
else if( control == IOBUFCTRL_INIT ) {
if( DBG_IOBUF )
log_debug("init block_filter %p\n", a );
if( a->partial )
a->count = 0;
else if( a->usage == 1 )
a->count = a->size = 0;
else
a->count = a->size; /* force first length bytes */
a->eof = 0;
}
else if( control == IOBUFCTRL_DESC ) {
*(char**)buf = "block_filter";
}
else if( control == IOBUFCTRL_FREE ) {
if( a->usage == 2 ) { /* write the end markers */
if( a->partial ) {
}
else {
iobuf_writebyte(chain, 0);
iobuf_writebyte(chain, 0);
}
}
else if( a->size ) {
log_error("block_filter: pending bytes!\n");
}
if( DBG_IOBUF )
log_debug("free block_filter %p\n", a );
m_free(a); /* we can free our context now */
}
return rc;
}
/****************
* Allocate a new io buffer, with no function assigned.
* Usage is the desired usage: 1 for input, 2 for output, 3 for temp buffer
* BUFSIZE is a suggested buffer size.
*/
IOBUF
iobuf_alloc(int usage, size_t bufsize)
{
IOBUF a;
static int number=0;
a = m_alloc_clear(sizeof *a);
a->usage = usage;
a->d.buf = m_alloc( bufsize );
a->d.size = bufsize;
a->no = ++number;
a->subno = 0;
a->opaque = NULL;
return a;
}
int
iobuf_close( IOBUF a )
{
IOBUF a2;
size_t dummy_len;
int rc=0;
for( ; a && !rc ; a = a2 ) {
a2 = a->chain;
if( a->usage == 2 && (rc=iobuf_flush(a)) )
log_error("iobuf_flush failed on close: %s\n", g10_errstr(rc));
if( DBG_IOBUF )
log_debug("iobuf-%d.%d: close '%s'\n", a->no, a->subno, a->desc );
if( a->filter && (rc = a->filter(a->filter_ov, IOBUFCTRL_FREE,
a->chain, NULL, &dummy_len)) )
log_error("IOBUFCTRL_FREE failed on close: %s\n", g10_errstr(rc) );
m_free(a->d.buf);
m_free(a);
}
return rc;
}
int
iobuf_cancel( IOBUF a )
{
const char *s;
if( a && a->usage == 2 ) {
s = iobuf_get_fname(a);
if( s && *s )
remove(s); /* remove the file. Fixme: this will fail for MSDOZE*/
} /* because the file is still open */
return iobuf_close(a);
}
/****************
* create a temporary iobuf, which can be used to collect stuff
* in an iobuf and later be written by iobuf_write_temp() to another
* iobuf.
*/
IOBUF
iobuf_temp()
{
IOBUF a;
a = iobuf_alloc(3, 8192 );
return a;
}
/****************
* Create a head iobuf for reading from a file
* returns: NULL if an error occures and sets errno
*/
IOBUF
iobuf_open( const char *fname )
{
IOBUF a;
FILE *fp;
file_filter_ctx_t *fcx;
size_t len;
if( !fname || (*fname=='-' && !fname[1]) ) {
fp = stdin; /* fixme: set binary mode for msdoze */
fname = "[stdin]";
}
else if( !(fp = fopen(fname, "rb")) )
return NULL;
a = iobuf_alloc(1, 8192 );
fcx = m_alloc( sizeof *fcx + strlen(fname) );
fcx->fp = fp;
strcpy(fcx->fname, fname );
a->filter = file_filter;
a->filter_ov = fcx;
file_filter( fcx, IOBUFCTRL_DESC, NULL, (byte*)&a->desc, &len );
file_filter( fcx, IOBUFCTRL_INIT, NULL, NULL, &len );
if( DBG_IOBUF )
log_debug("iobuf-%d.%d: open '%s'\n", a->no, a->subno, fname );
return a;
}
/****************
* create a iobuf for writing to a file; the file will be created.
*/
IOBUF
iobuf_create( const char *fname )
{
IOBUF a;
FILE *fp;
file_filter_ctx_t *fcx;
size_t len;
if( !fname || (*fname=='-' && !fname[1]) ) {
fp = stdout;
fname = "[stdout]";
}
else if( !(fp = fopen(fname, "wb")) )
return NULL;
a = iobuf_alloc(2, 8192 );
fcx = m_alloc( sizeof *fcx + strlen(fname) );
fcx->fp = fp;
strcpy(fcx->fname, fname );
a->filter = file_filter;
a->filter_ov = fcx;
file_filter( fcx, IOBUFCTRL_DESC, NULL, (byte*)&a->desc, &len );
file_filter( fcx, IOBUFCTRL_INIT, NULL, NULL, &len );
if( DBG_IOBUF )
log_debug("iobuf-%d.%d: create '%s'\n", a->no, a->subno, a->desc );
return a;
}
/****************
* append to a iobuf if the file does not exits; create it.
* cannont be used for stdout.
*/
IOBUF
iobuf_append( const char *fname )
{
IOBUF a;
FILE *fp;
file_filter_ctx_t *fcx;
size_t len;
if( !fname )
return NULL;
else if( !(fp = fopen(fname, "ab")) )
return NULL;
a = iobuf_alloc(2, 8192 );
fcx = m_alloc( sizeof *fcx + strlen(fname) );
fcx->fp = fp;
strcpy(fcx->fname, fname );
a->filter = file_filter;
a->filter_ov = fcx;
file_filter( fcx, IOBUFCTRL_DESC, NULL, (byte*)&a->desc, &len );
file_filter( fcx, IOBUFCTRL_INIT, NULL, NULL, &len );
if( DBG_IOBUF )
log_debug("iobuf-%d.%d: append '%s'\n", a->no, a->subno, a->desc );
return a;
}
IOBUF
iobuf_openrw( const char *fname )
{
IOBUF a;
FILE *fp;
file_filter_ctx_t *fcx;
size_t len;
if( !fname )
return NULL;
else if( !(fp = fopen(fname, "r+b")) )
return NULL;
a = iobuf_alloc(2, 8192 );
fcx = m_alloc( sizeof *fcx + strlen(fname) );
fcx->fp = fp;
strcpy(fcx->fname, fname );
a->filter = file_filter;
a->filter_ov = fcx;
file_filter( fcx, IOBUFCTRL_DESC, NULL, (byte*)&a->desc, &len );
file_filter( fcx, IOBUFCTRL_INIT, NULL, NULL, &len );
if( DBG_IOBUF )
log_debug("iobuf-%d.%d: openrw '%s'\n", a->no, a->subno, a->desc );
return a;
}
/****************
* Register an i/o filter.
*/
int
iobuf_push_filter( IOBUF a,
int (*f)(void *opaque, int control,
IOBUF chain, byte *buf, size_t *len), void *ov )
{
IOBUF b;
size_t dummy_len=0;
int rc=0;
if( a->usage == 2 && (rc=iobuf_flush(a)) )
return rc;
/* make a copy of the current stream, so that
* A is the new stream and B the original one.
* The contents of the buffers are transferred to the
* new stream.
*/
b = m_alloc(sizeof *b);
memcpy(b, a, sizeof *b );
/* remove the filter stuff from the new stream */
a->filter = NULL;
a->filter_ov = NULL;
a->filter_eof = 0;
if( a->usage == 2 ) { /* allocate a fresh buffer for the original stream */
b->d.buf = m_alloc( a->d.size );
b->d.len = 0;
b->d.start = 0;
}
else { /* allocate a fresh buffer for the new stream */
a->d.buf = m_alloc( a->d.size );
a->d.len = 0;
a->d.start = 0;
}
/* disable nlimit for the new stream */
a->ntotal = b->ntotal + b->nbytes;
a->nlimit = a->nbytes = 0;
/* make a link from the new stream to the original stream */
a->chain = b;
a->opaque = b->opaque;
/* setup the function on the new stream */
a->filter = f;
a->filter_ov = ov;
a->subno = b->subno + 1;
f( ov, IOBUFCTRL_DESC, NULL, (byte*)&a->desc, &dummy_len );
if( DBG_IOBUF ) {
log_debug("iobuf-%d.%d: push '%s'\n", a->no, a->subno, a->desc );
for(b=a; b; b = b->chain )
log_debug("\tchain: %d.%d '%s'\n", b->no, b->subno, b->desc );
}
/* now we can initialize the new function if we have one */
if( a->filter && (rc = a->filter(a->filter_ov, IOBUFCTRL_INIT, a->chain,
NULL, &dummy_len)) )
log_error("IOBUFCTRL_INIT failed: %s\n", g10_errstr(rc) );
return rc;
}
/****************
* Remove an i/o filter.
*/
int
iobuf_pop_filter( IOBUF a, int (*f)(void *opaque, int control,
IOBUF chain, byte *buf, size_t *len), void *ov )
{
IOBUF b;
size_t dummy_len=0;
int rc=0;
if( DBG_IOBUF )
log_debug("iobuf-%d.%d: pop '%s'\n", a->no, a->subno, a->desc );
if( !a->filter ) { /* this is simple */
b = a->chain;
assert(b);
m_free(a->d.buf);
memcpy(a,b, sizeof *a);
m_free(b);
return 0;
}
for(b=a ; b; b = b->chain )
if( b->filter == f && (!ov || b->filter_ov == ov) )
break;
if( !b )
log_bug("iobuf_pop_filter(): filter function not found\n");
/* flush this stream if it is an output stream */
if( a->usage == 2 && (rc=iobuf_flush(b)) ) {
log_error("iobuf_flush failed in pop_filter: %s\n", g10_errstr(rc));
return rc;
}
/* and tell the filter to free it self */
if( (rc = b->filter(b->filter_ov, IOBUFCTRL_FREE, b->chain,
NULL, &dummy_len)) ) {
log_error("IOBUFCTRL_FREE failed: %s\n", g10_errstr(rc) );
return rc;
}
/* and look how to remove it */
if( a == b && !b->chain )
log_bug("can't remove the last filter from the chain\n");
else if( a == b ) { /* remove the first iobuf from the chain */
/* everything from b is copied to a. This is save because
* a flush has been done on the to be removed entry
*/
b = a->chain;
m_free(a->d.buf);
memcpy(a,b, sizeof *a);
m_free(b);
}
else if( !b->chain ) { /* remove the last iobuf from the chain */
log_bug("Ohh jeee, trying to remove a head filter\n");
}
else { /* remove an intermediate iobuf from the chain */
log_bug("Ohh jeee, trying to remove an intermediate filter\n");
}
return rc;
}
/****************
* read underflow: read more bytes into the buffer and return
* the first byte or -1 on EOF.
*/
static int
underflow(IOBUF a)
{
size_t len;
int rc;
/*log_debug("iobuf-%d.%d: underflow: start=%lu len=%lu\n",
a->no, a->subno, (ulong)a->d.start, (ulong)a->d.len );*/
assert( a->d.start == a->d.len );
if( a->usage == 3 )
return -1; /* EOF because a temp buffer can't do an underflow */
if( a->filter_eof ) {
if( DBG_IOBUF )
log_debug("iobuf-%d.%d: filter eof\n", a->no, a->subno );
return -1;
}
if( a->filter ) {
len = a->d.size;
rc = a->filter( a->filter_ov, IOBUFCTRL_UNDERFLOW, a->chain,
a->d.buf, &len );
if( a->usage == 1 && rc == -1 ) { /* EOF: we can remove the filter */
size_t dummy_len;
/* and tell the filter to free it self */
if( a->filter != file_filter ) {
if( (rc = a->filter(a->filter_ov, IOBUFCTRL_FREE, a->chain,
NULL, &dummy_len)) )
log_error("IOBUFCTRL_FREE failed: %s\n", g10_errstr(rc) );
a->filter = NULL;
a->desc = NULL;
a->filter_ov = NULL;
}
a->filter_eof = 1;
}
if( !len )
return -1;
a->d.len = len;
a->d.start = 0;
return a->d.buf[a->d.start++];
}
else
return -1; /* no filter; return EOF */
}
void
iobuf_clear_eof(IOBUF a)
{
assert(a->usage == 1);
if( a->filter )
log_info("iobuf-%d.%d: clear_eof '%s' with enabled filter\n", a->no, a->subno, a->desc );
if( !a->filter_eof )
log_info("iobuf-%d.%d: clear_eof '%s' with no EOF pending\n", a->no, a->subno, a->desc );
iobuf_pop_filter(a, NULL, NULL);
}
int
iobuf_flush(IOBUF a)
{
size_t len;
int rc;
/*log_debug("iobuf-%d.%d: flush\n", a->no, a->subno );*/
if( a->usage == 3 )
log_bug("temp buffer too short\n");
else if( a->usage != 2 )
log_bug("flush on non-output iobuf\n");
else if( !a->filter )
log_bug("iobuf_flush: no filter\n");
len = a->d.len;
rc = a->filter( a->filter_ov, IOBUFCTRL_FLUSH, a->chain, a->d.buf, &len );
if( !rc && len != a->d.len ) {
log_info("iobuf_flush did not write all!\n");
rc = G10ERR_WRITE_FILE;
}
a->d.len = 0;
return rc;
}
/****************
* Read a byte from the iobuf; returns -1 on EOF
*/
int
iobuf_readbyte(IOBUF a)
{
int c;
/* nlimit does not work together with unget */
/* nbytes is also not valid! */
if( a->unget.buf ) {
if( a->unget.start < a->unget.len )
return a->unget.buf[a->unget.start++];
m_free(a->unget.buf);
a->unget.buf = NULL;
}
if( a->nlimit && a->nbytes >= a->nlimit )
return -1; /* forced EOF */
if( a->d.start < a->d.len ) {
c = a->d.buf[a->d.start++];
}
else if( (c=underflow(a)) == -1 )
return -1; /* EOF */
a->nbytes++;
return c;
}
int
iobuf_read(IOBUF a, byte *buf, unsigned buflen )
{
int c, n;
for(n=0 ; n < buflen; n++, buf++ ) {
if( (c = iobuf_readbyte(a)) == -1 ) {
if( !n )
return -1; /* eof */
break;
}
else
*buf = c;
}
return n;
}
/****************
* Have a look at the iobuf.
* NOTE: This does only work in special cases.
*/
int
iobuf_peek(IOBUF a, byte *buf, unsigned buflen )
{
int n=0;
if( !(a->d.start < a->d.len) ) {
if( underflow(a) == -1 )
return -1;
/* and unget this character */
assert(a->d.start == 1);
a->d.start = 0;
}
for(n=0 ; n < buflen && (a->d.start+n) < a->d.len ; n++, buf++ )
*buf = a->d.buf[n];
return n;
}
int
iobuf_writebyte(IOBUF a, unsigned c)
{
if( a->d.len == a->d.size )
if( iobuf_flush(a) )
return -1;
assert( a->d.len < a->d.size );
a->d.buf[a->d.len++] = c;
return 0;
}
int
iobuf_write(IOBUF a, byte *buf, unsigned buflen )
{
for( ; buflen; buflen--, buf++ )
if( iobuf_writebyte(a, *buf) )
return -1;
return 0;
}
int
iobuf_writestr(IOBUF a, const char *buf )
{
for( ; *buf; buf++ )
if( iobuf_writebyte(a, *buf) )
return -1;
return 0;
}
/****************
* copy the contents of TEMP to A.
*/
int
iobuf_write_temp( IOBUF a, IOBUF temp )
{
return iobuf_write(a, temp->d.buf, temp->d.len );
}
/****************
* copy the contents of the temp io stream to BUFFER.
*/
size_t
iobuf_temp_to_buffer( IOBUF a, byte *buffer, size_t buflen )
{
size_t n = a->d.len;
if( n > buflen )
n = buflen;
memcpy( buffer, a->d.buf, n );
return n;
}
/****************
* unget the contents of the temp io stream to A and close temp
* Could be optimized!!
*/
void
iobuf_unget_and_close_temp( IOBUF a, IOBUF temp )
{
if( a->unget.buf ) {
if( a->unget.start < a->unget.len )
log_fatal("cannot do any more ungets on this buffer\n");
/* not yet cleaned up; do it now */
m_free(a->unget.buf);
a->unget.buf = NULL;
}
a->unget.size = temp->d.len;
a->unget.buf = m_alloc( a->unget.size );
a->unget.len = temp->d.len;
memcpy( a->unget.buf, temp->d.buf, a->unget.len );
iobuf_close(temp);
}
/****************
* Set a limit, how much bytes may be read from the input stream A.
* Setting the limit to 0 disables this feature.
*/
void
iobuf_set_limit( IOBUF a, unsigned long nlimit )
{
a->nlimit = nlimit;
a->ntotal += a->nbytes;
a->nbytes = 0;
}
/****************
* Return the length of an open file
*/
u32
iobuf_get_filelength( IOBUF a )
{
struct stat st;
for( ; a; a = a->chain )
if( !a->chain && a->filter == file_filter ) {
file_filter_ctx_t *b = a->filter_ov;
FILE *fp = b->fp;
if( !fstat(fileno(fp), &st) )
return st.st_size;
log_error("fstat() failed: %s\n", strerror(errno) );
break;
}
return 0;
}
/****************
* Tell the file position, where the next read will take place
*/
ulong
iobuf_tell( IOBUF a )
{
return a->ntotal + a->nbytes;
}
/****************
* This is a very limited implementation. It simply discards all internal
* buffering and remove all filters but the first one.
*/
int
iobuf_seek( IOBUF a, ulong newpos )
{
file_filter_ctx_t *b = NULL;
for( ; a; a = a->chain ) {
if( !a->chain && a->filter == file_filter ) {
b = a->filter_ov;
break;
}
}
if( !a )
return -1;
if( fseek( b->fp, newpos, SEEK_SET ) ) {
log_error("can't seek to %lu: %s\n", newpos, strerror(errno) );
return -1;
}
a->d.len = 0; /* discard buffer */
a->d.start = 0;
a->nbytes = 0;
a->nlimit = 0;
a->ntotal = newpos;
/* remove filters, but the last */
while( a->chain )
iobuf_pop_filter( a, a->filter, NULL );
return 0;
}
/****************
* Retrieve the filename
*/
const char *
iobuf_get_fname( IOBUF a )
{
for( ; a; a = a->chain )
if( !a->chain && a->filter == file_filter ) {
file_filter_ctx_t *b = a->filter_ov;
return b->fname;
}
return NULL;
}
/****************
* Start the block write mode, see rfc1991.new for details.
* A value of 0 for N stops this mode (flushes and writes
* the end marker)
*/
void
iobuf_set_block_mode( IOBUF a, size_t n )
{
block_filter_ctx_t *ctx = m_alloc_clear( sizeof *ctx );
assert( a->usage == 1 || a->usage == 2 );
ctx->usage = a->usage;
if( !n ) {
iobuf_pop_filter(a, block_filter, NULL );
}
else {
ctx->size = n; /* only needed for usage 2 */
iobuf_push_filter(a, block_filter, ctx );
}
}
/****************
* enable patial block mode as descriped in the OpenPGP draft.
* LEN is the first length
*/
void
iobuf_set_partial_block_mode( IOBUF a, size_t len )
{
block_filter_ctx_t *ctx = m_alloc_clear( sizeof *ctx );
assert( a->usage == 1 || a->usage == 2 );
ctx->usage = a->usage;
if( !len ) {
iobuf_pop_filter(a, block_filter, NULL );
}
else {
ctx->partial = 1;
ctx->size = len;
iobuf_push_filter(a, block_filter, ctx );
}
}
/****************
* Checks wether the stream is in block mode
* Note: This does not work if other filters are pushed on the stream.
*/
int
iobuf_in_block_mode( IOBUF a )
{
if( a && a->filter == block_filter )
return 1; /* yes */
return 0; /* no */
}
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