Merge branch 'master' into mcb-tcp-xfer

src/core/asprintf.c

@@ -0,0 +1,47 @@
+#include <stdint.h>
+#include <stddef.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <errno.h>
+
+/**
+ * Write a formatted string to newly allocated memory.
+ *
+ * @v strp		Pointer to hold allocated string
+ * @v fmt		Format string
+ * @v args		Arguments corresponding to the format string
+ * @ret	len		Length of formatted string
+ */
+int vasprintf ( char **strp, const char *fmt, va_list args ) {
+	size_t len;
+	va_list args_tmp;
+
+	/* Calculate length needed for string */
+	va_copy ( args_tmp, args );
+	len = ( vsnprintf ( NULL, 0, fmt, args_tmp ) + 1 );
+	va_end ( args_tmp );
+
+	/* Allocate and fill string */
+	*strp = malloc ( len );
+	if ( ! *strp )
+		return -ENOMEM;
+	return vsnprintf ( *strp, len, fmt, args );
+}
+
+/**
+ * Write a formatted string to newly allocated memory.
+ *
+ * @v strp		Pointer to hold allocated string
+ * @v fmt		Format string
+ * @v ...		Arguments corresponding to the format string
+ * @ret	len		Length of formatted string
+ */
+int asprintf ( char **strp, const char *fmt, ... ) {
+	va_list args;
+	int len;
+
+	va_start ( args, fmt );
+	len = vasprintf ( strp, fmt, args );
+	va_end ( args );
+	return len;
+}

src/core/basename.c

@@ -38,3 +38,25 @@ char * basename ( char *path ) {
 	basename = strrchr ( path, '/' );
 	return ( basename ? ( basename + 1 ) : path );
 }
+
+/**
+ * Return directory name from path
+ *
+ * @v path		Full path
+ * @ret dirname		Directory name
+ *
+ * Note that this function may modify its argument.
+ */
+char * dirname ( char *path ) {
+	char *separator;
+
+	separator = strrchr ( path, '/' );
+	if ( separator == path ) {
+		return "/";
+	} else if ( separator ) {
+		*separator = 0;
+		return path;
+	} else {
+		return ".";
+	}
+}

src/core/download.c

@@ -121,7 +121,7 @@ int start_download ( const char *uri_string, struct async *parent,
  err:
 	async_uninit ( &download->async );
 	ufree ( download->buffer.addr );
-	free_uri ( download->uri );
+	uri_put ( download->uri );
 	free ( download );
 	return rc;
 }
@@ -150,7 +150,7 @@ static void download_sigchld ( struct async *async,
 		/* Discard the buffer */
 		ufree ( download->buffer.addr );
 	}
-	free_uri ( download->uri );
+	uri_put ( download->uri );
 	download->uri = NULL;
 
 	/* Terminate ourselves */

src/core/downloader.c

@@ -114,19 +114,6 @@ static int downloader_ensure_size ( struct downloader *downloader,
  *
  */
 
-/**
- * Handle start() event received via job control interface
- *
- * @v job		Downloader job control interface
- */
-static void downloader_job_start ( struct job_interface *job ) {
-	struct downloader *downloader = 
-		container_of ( job, struct downloader, job );
-
-	/* Start data transfer */
-	xfer_request_all ( &downloader->xfer );
-}
-
 /**
  * Handle kill() event received via job control interface
  *
@@ -142,7 +129,7 @@ static void downloader_job_kill ( struct job_interface *job ) {
 
 /** Downloader job control interface operations */
 static struct job_interface_operations downloader_job_operations = {
-	.start		= downloader_job_start,
+	.start		= ignore_job_start,
 	.done		= ignore_job_done,
 	.kill		= downloader_job_kill,
 	.progress	= ignore_job_progress,

src/core/hw.c

@@ -3,6 +3,7 @@
 #include <string.h>
 #include <errno.h>
 #include <gpxe/refcnt.h>
+#include <gpxe/process.h>
 #include <gpxe/xfer.h>
 #include <gpxe/open.h>
 
@@ -15,6 +16,7 @@
 struct hw {
 	struct refcnt refcnt;
 	struct xfer_interface xfer;
+	struct process process;
 };
 
 static const char hw_msg[] = "Hello world!\n";
@@ -22,6 +24,7 @@ static const char hw_msg[] = "Hello world!\n";
 static void hw_finished ( struct hw *hw, int rc ) {
 	xfer_nullify ( &hw->xfer );
 	xfer_close ( &hw->xfer, rc );
+	process_del ( &hw->process );
 }
 
 static void hw_xfer_close ( struct xfer_interface *xfer, int rc ) {
@@ -30,26 +33,25 @@ static void hw_xfer_close ( struct xfer_interface *xfer, int rc ) {
 	hw_finished ( hw, rc );
 }
 
-static int hw_xfer_request ( struct xfer_interface *xfer,
-			     off_t start __unused, int whence __unused,
-			     size_t len __unused ) {
-	struct hw *hw = container_of ( xfer, struct hw, xfer );
-	int rc;
-
-	rc = xfer_deliver_raw ( xfer, hw_msg, sizeof ( hw_msg ) );
-	hw_finished ( hw, rc );
-	return 0;
-}
-
 static struct xfer_interface_operations hw_xfer_operations = {
 	.close		= hw_xfer_close,
 	.vredirect	= ignore_xfer_vredirect,
-	.request	= hw_xfer_request,
+	.request	= ignore_xfer_request,
 	.seek		= ignore_xfer_seek,
 	.deliver_iob	= xfer_deliver_as_raw,
 	.deliver_raw	= ignore_xfer_deliver_raw,
 };
 
+static void hw_step ( struct process *process ) {
+	struct hw *hw = container_of ( process, struct hw, process );
+	int rc;
+
+	if ( xfer_ready ( &hw->xfer ) == 0 ) {
+		rc = xfer_deliver_raw ( &hw->xfer, hw_msg, sizeof ( hw_msg ) );
+		hw_finished ( hw, rc );
+	}
+}
+
 static int hw_open ( struct xfer_interface *xfer, struct uri *uri __unused ) {
 	struct hw *hw;
 
@@ -59,6 +61,7 @@ static int hw_open ( struct xfer_interface *xfer, struct uri *uri __unused ) {
 		return -ENOMEM;
 	memset ( hw, 0, sizeof ( *hw ) );
 	xfer_init ( &hw->xfer, &hw_xfer_operations, &hw->refcnt );
+	process_init ( &hw->process, hw_step, &hw->refcnt );
 
 	/* Attach parent interface, mortalise self, and return */
 	xfer_plug_plug ( &hw->xfer, xfer );

src/core/open.c

@@ -52,6 +52,7 @@ static struct socket_opener socket_openers_end[0]
 int xfer_open_uri ( struct xfer_interface *xfer, const char *uri_string ) {
 	struct uri *uri;
 	struct uri_opener *opener;
+	int rc = -ENOTSUP;
 
 	DBGC ( xfer, "XFER %p opening URI %s\n", xfer, uri_string );
 
@@ -61,44 +62,45 @@ int xfer_open_uri ( struct xfer_interface *xfer, const char *uri_string ) {
 
 	for ( opener = uri_openers ; opener < uri_openers_end ; opener++ ) {
 		if ( strcmp ( uri->scheme, opener->scheme ) == 0 ) {
-			return opener->open ( xfer, uri );
+			rc = opener->open ( xfer, uri );
+			goto done;
 		}
 	}
 
 	DBGC ( xfer, "XFER %p attempted to open unsupported URI scheme "
 	       "\"%s\"\n", xfer, uri->scheme );
-	free_uri ( uri );
-	return -ENOTSUP;
+ done:
+	uri_put ( uri );
+	return rc;
 }
 
 /**
  * Open socket
  *
  * @v xfer		Data transfer interface
- * @v domain		Communication domain (e.g. PF_INET)
- * @v type		Communication semantics (e.g. SOCK_STREAM)
+ * @v semantics		Communication semantics (e.g. SOCK_STREAM)
  * @v peer		Peer socket address
  * @v local		Local socket address, or NULL
  * @ret rc		Return status code
  */
-int xfer_open_socket ( struct xfer_interface *xfer,
-		       int domain, int type, struct sockaddr *peer,
-		       struct sockaddr *local ) {
+int xfer_open_socket ( struct xfer_interface *xfer, int semantics,
+		       struct sockaddr *peer, struct sockaddr *local ) {
 	struct socket_opener *opener;
 
 	DBGC ( xfer, "XFER %p opening (%s,%s) socket\n", xfer,
-	       socket_domain_name ( domain ), socket_type_name ( type ) );
+	       socket_semantics_name ( semantics ),
+	       socket_family_name ( peer->sa_family ) );
 
 	for ( opener = socket_openers; opener < socket_openers_end; opener++ ){
-		if ( ( opener->domain == domain ) &&
-		     ( opener->type == type ) ) {
+		if ( ( opener->semantics == semantics ) &&
+		     ( opener->family == peer->sa_family ) ) {
 			return opener->open ( xfer, peer, local );
 		}
 	}
 
 	DBGC ( xfer, "XFER %p attempted to open unsupported socket type "
-	       "(%s,%s)\n", xfer, socket_domain_name ( domain ),
-	       socket_type_name ( type ) );
+	       "(%s,%s)\n", xfer, socket_semantics_name ( semantics ),
+	       socket_family_name ( peer->sa_family ) );
 	return -ENOTSUP;
 }
 
@@ -117,12 +119,11 @@ int xfer_vopen ( struct xfer_interface *xfer, int type, va_list args ) {
 
 		return xfer_open_uri ( xfer, uri_string ); }
 	case LOCATION_SOCKET: {
-		int domain = va_arg ( args, int );
-		int type = va_arg ( args, int );
+		int semantics = va_arg ( args, int );
 		struct sockaddr *peer = va_arg ( args, struct sockaddr * );
 		struct sockaddr *local = va_arg ( args, struct sockaddr * );
 
-		return xfer_open_socket ( xfer, domain, type, peer, local ); }
+		return xfer_open_socket ( xfer, semantics, peer, local ); }
 	default:
 		DBGC ( xfer, "XFER %p attempted to open unsupported location "
 		       "type %d\n", xfer, type );

src/core/posix_io.c

@@ -78,6 +78,7 @@ static void posix_file_free ( struct refcnt *refcnt ) {
 	struct io_buffer *tmp;
 
 	list_for_each_entry_safe ( iobuf, tmp, &file->data, list ) {
+		list_del ( &iobuf->list );
 		free_iob ( iobuf );
 	}
 	free ( file );
@@ -190,6 +191,7 @@ static int posix_find_free_fd ( void ) {
 		if ( ! posix_fd_to_file ( fd ) )
 			return fd;
 	}
+	DBG ( "POSIX could not find free file descriptor\n" );
 	return -ENFILE;
 }
 
@@ -225,13 +227,11 @@ int open ( const char *uri_string ) {
 	if ( ( rc = xfer_open_uri ( &file->xfer, uri_string ) ) != 0 )
 		goto err;
 
-	/* Request data */
-	if ( ( rc = xfer_request_all ( &file->xfer ) ) != 0 )
-		goto err;
-
 	/* Wait for open to succeed or fail */
 	while ( list_empty ( &file->data ) ) {
 		step();
+		if ( file->rc == 0 )
+			break;
 		if ( file->rc != -EINPROGRESS ) {
 			rc = file->rc;
 			goto err;
@@ -240,6 +240,7 @@ int open ( const char *uri_string ) {
 
 	/* Add to list of open files.  List takes reference ownership. */
 	list_add ( &file->list, &posix_files );
+	DBG ( "POSIX opened %s as file %d\n", uri_string, fd );
 	return fd;
 
  err:
@@ -279,8 +280,10 @@ ssize_t read_user ( int fd, userptr_t buffer, off_t offset, size_t max_len ) {
 			copy_to_user ( buffer, offset, iobuf->data,
 				       frag_len );
 			iob_pull ( iobuf, frag_len );
-			if ( ! iob_len ( iobuf ) )
+			if ( ! iob_len ( iobuf ) ) {
+				list_del ( &iobuf-> list );
 				free_iob ( iobuf );
+			}
 			file->pos += frag_len;
 			len += frag_len;
 			offset += frag_len;

src/core/process.c

@@ -31,25 +31,43 @@
 static LIST_HEAD ( run_queue );
 
 /**
- * Add process to run queue
+ * Add process to process list
  *
  * @v process		Process
  */
-void schedule ( struct process *process ) {
+void process_add ( struct process *process ) {
+	ref_get ( process->refcnt );
 	list_add_tail ( &process->list, &run_queue );
 }
 
+/**
+ * Remove process from process list
+ *
+ * @v process		Process
+ *
+ * It is safe to call process_del() multiple times; further calls will
+ * have no effect.
+ */
+void process_del ( struct process *process ) {
+	if ( ! list_empty ( &process->list ) ) {
+		list_del ( &process->list );
+		INIT_LIST_HEAD ( &process->list );
+		ref_put ( process->refcnt );
+	}
+}
+
 /**
  * Single-step a single process
  *
- * This removes the first process from the run queue and executes a
- * single step of that process.
+ * This executes a single step of the first process in the run queue,
+ * and moves the process to the end of the run queue.
  */
 void step ( void ) {
 	struct process *process;
 
 	list_for_each_entry ( process, &run_queue, list ) {
 		list_del ( &process->list );
+		list_add_tail ( &process->list, &run_queue );
 		process->step ( process );
 		break;
 	}

src/core/refcnt.c

@@ -39,8 +39,8 @@ void ref_get ( struct refcnt *refcnt ) {
 
 	refcnt->refcnt++;
 
-	DBGC ( refcnt, "REFCNT %p incremented to %d\n",
-	       refcnt, refcnt->refcnt );
+	DBGC2 ( refcnt, "REFCNT %p incremented to %d\n",
+		refcnt, refcnt->refcnt );
 }
 
 /**
@@ -59,8 +59,8 @@ void ref_put ( struct refcnt *refcnt ) {
 		return;
 
 	refcnt->refcnt--;
-	DBGC ( refcnt, "REFCNT %p decremented to %d\n",
-	       refcnt, refcnt->refcnt );
+	DBGC2 ( refcnt, "REFCNT %p decremented to %d\n",
+		refcnt, refcnt->refcnt );
 
 	if ( refcnt->refcnt >= 0 )
 		return;

src/core/uri.c

@@ -25,8 +25,36 @@
 #include <stdint.h>
 #include <stdlib.h>
 #include <string.h>
+#include <libgen.h>
+#include <gpxe/vsprintf.h>
 #include <gpxe/uri.h>
 
+/**
+ * Dump URI for debugging
+ *
+ * @v uri		URI
+ */
+static void dump_uri ( struct uri *uri ) {
+	if ( uri->scheme )
+		DBG ( " scheme \"%s\"", uri->scheme );
+	if ( uri->opaque )
+		DBG ( " opaque \"%s\"", uri->opaque );
+	if ( uri->user )
+		DBG ( " user \"%s\"", uri->user );
+	if ( uri->password )
+		DBG ( " password \"%s\"", uri->password );
+	if ( uri->host )
+		DBG ( " host \"%s\"", uri->host );
+	if ( uri->port )
+		DBG ( " port \"%s\"", uri->port );
+	if ( uri->path )
+		DBG ( " path \"%s\"", uri->path );
+	if ( uri->query )
+		DBG ( " query \"%s\"", uri->query );
+	if ( uri->fragment )
+		DBG ( " fragment \"%s\"", uri->fragment );
+}
+
 /**
  * Parse URI
  *
@@ -35,7 +63,7 @@
  *
  * Splits a URI into its component parts.  The return URI structure is
  * dynamically allocated and must eventually be freed by calling
- * free_uri().
+ * uri_put().
  */
 struct uri * parse_uri ( const char *uri_string ) {
 	struct uri *uri;
@@ -136,25 +164,8 @@ struct uri * parse_uri ( const char *uri_string ) {
 	}
 
  done:
-	DBG ( "URI \"%s\" split into", raw );
-	if ( uri->scheme )
-		DBG ( " scheme \"%s\"", uri->scheme );
-	if ( uri->opaque )
-		DBG ( " opaque \"%s\"", uri->opaque );
-	if ( uri->user )
-		DBG ( " user \"%s\"", uri->user );
-	if ( uri->password )
-		DBG ( " password \"%s\"", uri->password );
-	if ( uri->host )
-		DBG ( " host \"%s\"", uri->host );
-	if ( uri->port )
-		DBG ( " port \"%s\"", uri->port );
-	if ( uri->path )
-		DBG ( " path \"%s\"", uri->path );
-	if ( uri->query )
-		DBG ( " query \"%s\"", uri->query );
-	if ( uri->fragment )
-		DBG ( " fragment \"%s\"", uri->fragment );
+	DBG ( "URI \"%s\" split into", uri_string );
+	dump_uri ( uri );
 	DBG ( "\n" );
 
 	return uri;
@@ -170,3 +181,193 @@ struct uri * parse_uri ( const char *uri_string ) {
 unsigned int uri_port ( struct uri *uri, unsigned int default_port ) {
 	return ( uri->port ? strtoul ( uri->port, NULL, 0 ) : default_port );
 }
+
+/**
+ * Unparse URI
+ *
+ * @v buf		Buffer to fill with URI string
+ * @v size		Size of buffer
+ * @v uri		URI to write into buffer
+ * @ret len		Length of URI string
+ */
+int unparse_uri ( char *buf, size_t size, struct uri *uri ) {
+	int used = 0;
+
+	DBG ( "URI unparsing" );
+	dump_uri ( uri );
+	DBG ( "\n" );
+
+	/* Special-case opaque URIs */
+	if ( uri->opaque ) {
+		return ssnprintf ( ( buf + used ), ( size - used ),
+				   "%s:%s", uri->scheme, uri->opaque );
+	}
+
+	/* scheme:// */
+	if ( uri->scheme ) {
+		used += ssnprintf ( ( buf + used ), ( size - used ),
+				    "%s://", uri->scheme );
+	}
+
+	/* [user[:password]@]host[:port] */
+	if ( uri->host ) {
+		if ( uri->user ) {
+			used += ssnprintf ( ( buf + used ), ( size - used ),
+					    "%s", uri->user );
+			if ( uri->password ) {
+				used += ssnprintf ( ( buf + used ),
+						    ( size - used ),
+						    ":%s", uri->password );
+			}
+			used += ssnprintf ( ( buf + used ), ( size - used ),
+					    "@" );
+		}
+		used += ssnprintf ( ( buf + used ), ( size - used ), "%s",
+				    uri->host );
+		if ( uri->port ) {
+			used += ssnprintf ( ( buf + used ), ( size - used ),
+					    ":%s", uri->port );
+		}
+	}
+
+	/* /path */
+	if ( uri->path ) {
+		used += ssnprintf ( ( buf + used ), ( size - used ),
+				    "%s", uri->path );
+	}
+
+	/* ?query */
+	if ( uri->query ) {
+		used += ssnprintf ( ( buf + used ), ( size - used ),
+				    "?%s", uri->query );
+	}
+
+	/* #fragment */
+	if ( uri->fragment ) {
+		used += ssnprintf ( ( buf + used ), ( size - used ),
+				    "#%s", uri->fragment );
+	}
+
+	return used;
+}
+
+/**
+ * Duplicate URI
+ *
+ * @v uri		URI
+ * @ret uri		Duplicate URI
+ *
+ * Creates a modifiable copy of a URI.
+ */
+struct uri * uri_dup ( struct uri *uri ) {
+	size_t len = ( unparse_uri ( NULL, 0, uri ) + 1 );
+	char buf[len];
+
+	unparse_uri ( buf, len, uri );
+	return parse_uri ( buf );
+}
+
+/**
+ * Resolve base+relative path
+ *
+ * @v base_uri		Base path
+ * @v relative_uri	Relative path
+ * @ret resolved_uri	Resolved path
+ *
+ * Takes a base path (e.g. "/var/lib/tftpboot/vmlinuz" and a relative
+ * path (e.g. "initrd.gz") and produces a new path
+ * (e.g. "/var/lib/tftpboot/initrd.gz").  Note that any non-directory
+ * portion of the base path will automatically be stripped; this
+ * matches the semantics used when resolving the path component of
+ * URIs.
+ */
+char * resolve_path ( const char *base_path,
+		      const char *relative_path ) {
+	size_t base_len = ( strlen ( base_path ) + 1 );
+	char base_path_copy[base_len];
+	char *base_tmp = base_path_copy;
+	char *resolved;
+
+	/* If relative path is absolute, just re-use it */
+	if ( relative_path[0] == '/' )
+		return strdup ( relative_path );
+
+	/* Create modifiable copy of path for dirname() */
+	memcpy ( base_tmp, base_path, base_len );
+	base_tmp = dirname ( base_tmp );
+
+	/* Process "./" and "../" elements */
+	while ( *relative_path == '.' ) {
+		relative_path++;
+		if ( *relative_path == 0 ) {
+			/* Do nothing */
+		} else if ( *relative_path == '/' ) {
+			relative_path++;
+		} else if ( *relative_path == '.' ) {
+			relative_path++;
+			if ( *relative_path == 0 ) {
+				base_tmp = dirname ( base_tmp );
+			} else if ( *relative_path == '/' ) {
+				base_tmp = dirname ( base_tmp );
+				relative_path++;
+			} else {
+				relative_path -= 2;
+				break;
+			}
+		} else {
+			relative_path--;
+			break;
+		}
+	}
+
+	/* Create and return new path */
+	if ( asprintf ( &resolved, "%s%s%s", base_tmp,
+			( ( base_tmp[ strlen ( base_tmp ) - 1 ] == '/' ) ?
+			  "" : "/" ), relative_path ) < 0 )
+		return NULL;
+
+	return resolved;
+}
+
+/**
+ * Resolve base+relative URI
+ *
+ * @v base_uri		Base URI
+ * @v relative_uri	Relative URI
+ * @ret resolved_uri	Resolved URI
+ *
+ * Takes a base URI (e.g. "http://etherboot.org/kernels/vmlinuz" and a
+ * relative URI (e.g. "../initrds/initrd.gz") and produces a new URI
+ * (e.g. "http://etherboot.org/initrds/initrd.gz").
+ */
+struct uri * resolve_uri ( struct uri *base_uri,
+			   struct uri *relative_uri ) {
+	struct uri tmp_uri;
+	char *tmp_path = NULL;
+	struct uri *new_uri;
+
+	/* If relative URI is absolute, just re-use it */
+	if ( uri_is_absolute ( relative_uri ) )
+		return uri_get ( relative_uri );
+
+	/* Mangle URI */
+	memcpy ( &tmp_uri, base_uri, sizeof ( tmp_uri ) );
+	if ( relative_uri->path ) {
+		tmp_path = resolve_path ( ( base_uri->path ?
+					    base_uri->path : "/" ),
+					  relative_uri->path );
+		tmp_uri.path = tmp_path;
+		tmp_uri.query = relative_uri->query;
+		tmp_uri.fragment = relative_uri->fragment;
+	} else if ( relative_uri->query ) {
+		tmp_uri.query = relative_uri->query;
+		tmp_uri.fragment = relative_uri->fragment;
+	} else if ( relative_uri->fragment ) {
+		tmp_uri.fragment = relative_uri->fragment;
+	}
+
+	/* Create demangled URI */
+	new_uri = uri_dup ( &tmp_uri );
+	free ( tmp_path );
+	return new_uri;
+}

src/core/vsprintf.c

@@ -338,6 +338,45 @@ int snprintf ( char *buf, size_t size, const char *fmt, ... ) {
 	return i;
 }
 
+/**
+ * Version of vsnprintf() that accepts a signed buffer size
+ *
+ * @v buf		Buffer into which to write the string
+ * @v size		Size of buffer
+ * @v fmt		Format string
+ * @v args		Arguments corresponding to the format string
+ * @ret len		Length of formatted string
+ */
+int vssnprintf ( char *buf, ssize_t ssize, const char *fmt, va_list args ) {
+
+	/* Treat negative buffer size as zero buffer size */
+	if ( ssize < 0 )
+		ssize = 0;
+
+	/* Hand off to vsnprintf */
+	return vsnprintf ( buf, ssize, fmt, args );
+}
+
+/**
+ * Version of vsnprintf() that accepts a signed buffer size
+ *
+ * @v buf		Buffer into which to write the string
+ * @v size		Size of buffer
+ * @v fmt		Format string
+ * @v ...		Arguments corresponding to the format string
+ * @ret len		Length of formatted string
+ */
+int ssnprintf ( char *buf, ssize_t ssize, const char *fmt, ... ) {
+	va_list args;
+	int len;
+
+	/* Hand off to vssnprintf */
+	va_start ( args, fmt );
+	len = vssnprintf ( buf, ssize, fmt, args );
+	va_end ( args );
+	return len;
+}
+
 /**
  * Write character to console
  *

src/core/xfer.c

@@ -17,6 +17,7 @@
  */
 
 #include <string.h>
+#include <stdio.h>
 #include <errno.h>
 #include <gpxe/xfer.h>
 
@@ -35,6 +36,8 @@
 void xfer_close ( struct xfer_interface *xfer, int rc ) {
 	struct xfer_interface *dest = xfer_get_dest ( xfer );
 
+	DBGC ( xfer, "XFER %p->%p close\n", xfer, dest );
+
 	dest->op->close ( dest, rc );
 	xfer_unplug ( xfer );
 	xfer_put ( dest );
@@ -52,7 +55,14 @@ int xfer_vredirect ( struct xfer_interface *xfer, int type, va_list args ) {
 	struct xfer_interface *dest = xfer_get_dest ( xfer );
 	int rc;
 
+	DBGC ( xfer, "XFER %p->%p redirect\n", xfer, dest );
+
 	rc = dest->op->vredirect ( dest, type, args );
+
+	if ( rc != 0 ) {
+		DBGC ( xfer, "XFER %p<-%p redirect: %s\n", xfer, dest,
+		       strerror ( rc ) );
+	}
 	xfer_put ( dest );
 	return rc;
 }
@@ -89,21 +99,19 @@ int xfer_request ( struct xfer_interface *xfer, off_t offset, int whence,
 	struct xfer_interface *dest = xfer_get_dest ( xfer );
 	int rc;
 
+	DBGC ( xfer, "XFER %p->%p request %s+%ld %zd\n", xfer, dest,
+	       whence_text ( whence ), offset, len );
+
 	rc = dest->op->request ( dest, offset, whence, len );
+
+	if ( rc != 0 ) {
+		DBGC ( xfer, "XFER %p<-%p request: %s\n", xfer, dest,
+		       strerror ( rc ) );
+	}
 	xfer_put ( dest );
 	return rc;
 }
 
-/**
- * Request all data
- *
- * @v xfer		Data transfer interface
- * @ret rc		Return status code
- */
-int xfer_request_all ( struct xfer_interface *xfer ) {
-	return xfer_request ( xfer, 0, SEEK_SET, ~( ( size_t ) 0 ) );
-}
-
 /**
  * Seek to position
  *
@@ -116,11 +124,33 @@ int xfer_seek ( struct xfer_interface *xfer, off_t offset, int whence ) {
 	struct xfer_interface *dest = xfer_get_dest ( xfer );
 	int rc;
 
+	DBGC ( xfer, "XFER %p->%p seek %s+%ld\n", xfer, dest,
+	       whence_text ( whence ), offset );
+
 	rc = dest->op->seek ( dest, offset, whence );
+
+	if ( rc != 0 ) {
+		DBGC ( xfer, "XFER %p<-%p seek: %s\n", xfer, dest,
+		       strerror ( rc ) );
+	}
 	xfer_put ( dest );
 	return rc;
 }
 
+/**
+ * Test to see if interface is ready to accept data
+ *
+ * @v xfer		Data transfer interface
+ * @ret rc		Return status code
+ *
+ * This test is optional; the data transfer interface may wish that it
+ * does not yet wish to accept data, but cannot prevent attempts to
+ * deliver data to it.
+ */
+int xfer_ready ( struct xfer_interface *xfer ) {
+	return xfer_seek ( xfer, 0, SEEK_CUR );
+}
+
 /**
  * Allocate I/O buffer
  *
@@ -132,7 +162,13 @@ struct io_buffer * xfer_alloc_iob ( struct xfer_interface *xfer, size_t len ) {
 	struct xfer_interface *dest = xfer_get_dest ( xfer );
 	struct io_buffer *iobuf;
 
+	DBGC ( xfer, "XFER %p->%p alloc_iob %zd\n", xfer, dest, len );
+
 	iobuf = dest->op->alloc_iob ( dest, len );
+
+	if ( ! iobuf ) {
+		DBGC ( xfer, "XFER %p<-%p alloc_iob failed\n", xfer, dest );
+	}
 	xfer_put ( dest );
 	return iobuf;
 }
@@ -148,7 +184,15 @@ int xfer_deliver_iob ( struct xfer_interface *xfer, struct io_buffer *iobuf ) {
 	struct xfer_interface *dest = xfer_get_dest ( xfer );
 	int rc;
 
+	DBGC ( xfer, "XFER %p->%p deliver_iob %zd\n", xfer, dest,
+	       iob_len ( iobuf ) );
+
 	rc = dest->op->deliver_iob ( dest, iobuf );
+
+	if ( rc != 0 ) {
+		DBGC ( xfer, "XFER %p<-%p deliver_iob: %s\n", xfer, dest,
+		       strerror ( rc ) );
+	}
 	xfer_put ( dest );
 	return rc;
 }
@@ -165,11 +209,60 @@ int xfer_deliver_raw ( struct xfer_interface *xfer,
 	struct xfer_interface *dest = xfer_get_dest ( xfer );
 	int rc;
 
+	DBGC ( xfer, "XFER %p->%p deliver_raw %p+%zd\n", xfer, dest,
+	       data, len );
+
 	rc = dest->op->deliver_raw ( dest, data, len );
+
+	if ( rc != 0 ) {
+		DBGC ( xfer, "XFER %p<-%p deliver_raw: %s\n", xfer, dest,
+		       strerror ( rc ) );
+	}
 	xfer_put ( dest );
 	return rc;
 }
 
+/**
+ * Deliver formatted string
+ *
+ * @v xfer		Data transfer interface
+ * @v format		Format string
+ * @v args		Arguments corresponding to the format string
+ * @ret rc		Return status code
+ */
+int xfer_vprintf ( struct xfer_interface *xfer, const char *format,
+		   va_list args ) {
+	size_t len;
+	va_list args_tmp;
+
+	va_copy ( args_tmp, args );
+	len = vsnprintf ( NULL, 0, format, args );
+	{
+		char buf[len + 1];
+		vsnprintf ( buf, sizeof ( buf ), format, args_tmp );
+		va_end ( args_tmp );
+		return xfer_deliver_raw ( xfer, buf, len );
+	}
+}
+
+/**
+ * Deliver formatted string
+ *
+ * @v xfer		Data transfer interface
+ * @v format		Format string
+ * @v ...		Arguments corresponding to the format string
+ * @ret rc		Return status code
+ */
+int xfer_printf ( struct xfer_interface *xfer, const char *format, ... ) {
+	va_list args;
+	int rc;
+
+	va_start ( args, format );
+	rc = xfer_vprintf ( xfer, format, args );
+	va_end ( args );
+	return rc;
+}
+
 /****************************************************************************
  *
  * Helper methods