initially checkin

util/iobuf.c

@@ -0,0 +1,762 @@
+/* iobuf.c  -  file handling
+ *	Copyright (c) 1997 by Werner Koch (dd9jn)
+ *
+ * This file is part of G10.
+ *
+ * G10 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.
+ *
+ * G10 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 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 */
+		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;
+
+	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->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 */
+	    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;
+    return a;
+}
+
+
+int
+iobuf_close( IOBUF a )
+{
+    IOBUF a2;
+    size_t dummy_len;
+    int rc=0;
+
+    for( ; a; 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->recorder.buf);
+	m_free(a->d.buf);
+	m_free(a);
+    }
+    return rc;
+}
+
+int
+iobuf_cancel( IOBUF a )
+{
+    /* FIXME: do an unlink if usage is 2 */
+    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 ) {
+	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 ) {
+	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;
+}
+
+/****************
+ * 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;
+    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->nlimit = a->nbytes = 0;
+    /* disable recorder for the original stream */
+    b->recorder.buf = NULL;
+    /* make a link from the new stream to the original stream */
+    a->chain = b;
+
+    /* 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 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( (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;
+
+    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++;
+
+    if( a->recorder.buf ) {
+	if( a->recorder.len >= a->recorder.size ) {
+	    a->recorder.size += 500;
+	    a->recorder.buf = m_realloc( a->recorder.buf, a->recorder.size );
+	}
+	((byte*)a->recorder.buf)[a->recorder.len++] = c;
+    }
+    return c;
+}
+
+
+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;
+}
+
+
+
+/****************
+ * 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;
+}
+
+
+/****************
+ * 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->nbytes = 0;
+}
+
+
+
+void
+iobuf_start_recorder( IOBUF a )
+{
+    m_free(a->recorder.buf);
+    a->recorder.size = 500;
+    a->recorder.buf = m_alloc(a->recorder.size);
+    a->recorder.len = 0;
+}
+
+void
+iobuf_push_recorder( IOBUF a, int c )
+{
+    if( a->recorder.buf ) {
+	if( a->recorder.len >= a->recorder.size ) {
+	    a->recorder.size += 500;
+	    a->recorder.buf = m_realloc( a->recorder.buf, a->recorder.size );
+	}
+	((byte*)a->recorder.buf)[a->recorder.len++] = c;
+    }
+}
+
+
+char *
+iobuf_stop_recorder( IOBUF a, size_t *n )
+{
+    char *p;
+    if( !a->recorder.buf )
+	log_bug("iobuf_recorder not started\n");
+    p = a->recorder.buf;
+    if( n )
+	*n = a->recorder.len;
+    a->recorder.buf = NULL;
+    return p;
+}
+
+
+/****************
+ * 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;
+}
+
+/****************
+ * 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 );
+    }
+}
+
+
+/****************
+ * checks wether the stream is in block mode
+ */
+int
+iobuf_in_block_mode( IOBUF a )
+{
+    for(; a; a = a->chain )
+	if( a->filter == block_filter )
+	    return 1; /* yes */
+    return 0; /* no */
+}
+
+
+