[efi] Add EFI string formatting functions

Signed-off-by: Michael Brown <mcb30@ipxe.org>

src/include/ipxe/efi/efi_strings.h

@@ -0,0 +1,23 @@
+#ifndef _IPXE_EFI_STRINGS_H
+#define _IPXE_EFI_STRINGS_H
+
+/** @file
+ *
+ * EFI strings
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER );
+
+#include <stddef.h>
+#include <stdint.h>
+#include <stdarg.h>
+
+extern int efi_vsnprintf ( wchar_t *wbuf, size_t wsize, const char *fmt,
+			   va_list args );
+extern int efi_snprintf ( wchar_t *wbuf, size_t wsize, const char *fmt, ... );
+extern int efi_vssnprintf ( wchar_t *wbuf, ssize_t swsize, const char *fmt,
+			    va_list args );
+extern int efi_ssnprintf ( wchar_t *wbuf, ssize_t swsize,
+			   const char *fmt, ... );
+
+#endif /* _IPXE_EFI_STRINGS_H */

src/interface/efi/efi_driver.c

@@ -23,6 +23,7 @@ FILE_LICENCE ( GPL2_OR_LATER );
 #include <ipxe/efi/efi.h>
 #include <ipxe/efi/Protocol/DriverBinding.h>
 #include <ipxe/efi/Protocol/ComponentName2.h>
+#include <ipxe/efi/efi_strings.h>
 #include <ipxe/efi/efi_driver.h>
 #include <config/general.h>
 
@@ -107,8 +108,6 @@ EFI_STATUS efi_driver_install ( struct efi_driver *efidrv ) {
 	EFI_BOOT_SERVICES *bs = efi_systab->BootServices;
 	EFI_DRIVER_BINDING_PROTOCOL *driver = &efidrv->driver;
 	EFI_COMPONENT_NAME2_PROTOCOL *wtf = &efidrv->wtf;
-	char buf[ sizeof ( efidrv->wname ) / sizeof ( efidrv->wname[0] ) ];
-	unsigned int i;
 	EFI_STATUS efirc;
 
 	/* Configure driver binding protocol */
@@ -120,12 +119,10 @@ EFI_STATUS efi_driver_install ( struct efi_driver *efidrv ) {
 	wtf->SupportedLanguages = "en";
 
 	/* Fill in driver name */
-	snprintf ( buf, sizeof ( buf ), PRODUCT_SHORT_NAME " - %s",
-		   efidrv->name );
-	for ( i = 0 ; i < sizeof ( buf ) ; i++ ) {
-		/* Damn Unicode names */
-		efidrv->wname[i] = *( ( ( unsigned char * ) buf ) + i );
-	}
+	efi_snprintf ( efidrv->wname,
+		       ( sizeof ( efidrv->wname ) /
+			 sizeof ( efidrv->wname[0] ) ),
+		       PRODUCT_SHORT_NAME " - %s", efidrv->name );
 
 	/* Install driver */
 	if ( ( efirc = bs->InstallMultipleProtocolInterfaces (

src/interface/efi/efi_snp.c

@@ -30,6 +30,7 @@ FILE_LICENCE ( GPL2_OR_LATER );
 #include <ipxe/efi/efi.h>
 #include <ipxe/efi/efi_pci.h>
 #include <ipxe/efi/efi_driver.h>
+#include <ipxe/efi/efi_strings.h>
 #include <ipxe/efi/Protocol/SimpleNetwork.h>
 #include <ipxe/efi/Protocol/NetworkInterfaceIdentifier.h>
 #include <ipxe/efi/Protocol/DevicePath.h>
@@ -772,7 +773,6 @@ static int efi_snp_probe ( struct net_device *netdev ) {
 	EFI_DEVICE_PATH_PROTOCOL *path_end;
 	MAC_ADDR_DEVICE_PATH *macpath;
 	size_t path_prefix_len = 0;
-	unsigned int i;
 	EFI_STATUS efirc;
 	int rc;
 
@@ -831,12 +831,9 @@ static int efi_snp_probe ( struct net_device *netdev ) {
 		  sizeof ( snpdev->nii.StringId ) );
 
 	/* Populate the device name */
-	for ( i = 0 ; i < sizeof ( netdev->name ) ; i++ ) {
-		/* Damn Unicode names */
-		assert ( i < ( sizeof ( snpdev->name ) /
-			       sizeof ( snpdev->name[0] ) ) );
-		snpdev->name[i] = netdev->name[i];
-	}
+	efi_snprintf ( snpdev->name, ( sizeof ( snpdev->name ) /
+				       sizeof ( snpdev->name[0] ) ),
+		       "%s", netdev->name );
 
 	/* Populate the device path */
 	memcpy ( &snpdev->path, efipci->path, path_prefix_len );

src/interface/efi/efi_strings.c

@@ -0,0 +1,147 @@
+/*
+ * Copyright (C) 2011 Michael Brown <mbrown@fensystems.co.uk>.
+ *
+ * This program 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 any later version.
+ *
+ * This program 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., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER );
+
+#include <stddef.h>
+#include <stdarg.h>
+#include <ipxe/vsprintf.h>
+#include <ipxe/efi/efi_strings.h>
+
+/** Context used by efi_vsnprintf() and friends */
+struct efi_sputc_context {
+	/** printf context */
+	struct printf_context ctx;
+	/** Buffer for formatted string (used by efi_printf_sputc()) */
+	wchar_t *buf;
+	/** Buffer length (used by efi_printf_sputc())
+	 *
+	 * Note that this is a number of wide characters, not a number
+	 * of bytes.
+	 */
+	size_t max_wlen;
+};
+
+/**
+ * Write wide character to buffer
+ *
+ * @v ctx		Context
+ * @v c			Character
+ */
+static void efi_printf_sputc ( struct printf_context *ctx, unsigned int c ) {
+	struct efi_sputc_context * sctx =
+		container_of ( ctx, struct efi_sputc_context, ctx );
+
+	if ( ctx->len < sctx->max_wlen )
+		sctx->buf[ctx->len] = c;
+}
+
+/**
+ * Write a formatted string to a wide-character buffer
+ *
+ * @v wbuf		Buffer into which to write the string
+ * @v wsize		Size of buffer (in wide characters)
+ * @v fmt		Format string
+ * @v args		Arguments corresponding to the format string
+ * @ret wlen		Length of formatted string (in wide characters)
+ *
+ * If the buffer is too small to contain the string, the returned
+ * length is the length that would have been written had enough space
+ * been available.
+ */
+int efi_vsnprintf ( wchar_t *wbuf, size_t wsize, const char *fmt,
+		    va_list args ) {
+	struct efi_sputc_context sctx;
+	size_t wlen;
+	size_t wend;
+
+	/* Hand off to vcprintf */
+	sctx.ctx.handler = efi_printf_sputc;
+	sctx.buf = wbuf;
+	sctx.max_wlen = wsize;
+	wlen = vcprintf ( &sctx.ctx, fmt, args );
+
+	/* Add trailing NUL */
+	if ( wsize ) {
+		wend = wsize - 1;
+		if ( wlen < wend )
+			wend = wlen;
+		wbuf[wend] = '\0';
+	}
+
+	return wlen;
+}
+
+/**
+ * Write a formatted string to a buffer
+ *
+ * @v wbuf		Buffer into which to write the string
+ * @v wsize		Size of buffer (in wide characters)
+ * @v fmt		Format string
+ * @v ...		Arguments corresponding to the format string
+ * @ret wlen		Length of formatted string (in wide characters)
+ */
+int efi_snprintf ( wchar_t *wbuf, size_t wsize, const char *fmt, ... ) {
+	va_list args;
+	int i;
+
+	va_start ( args, fmt );
+	i = efi_vsnprintf ( wbuf, wsize, fmt, args );
+	va_end ( args );
+	return i;
+}
+
+/**
+ * Version of efi_vsnprintf() that accepts a signed buffer size
+ *
+ * @v wbuf		Buffer into which to write the string
+ * @v swsize		Size of buffer (in wide characters)
+ * @v fmt		Format string
+ * @v args		Arguments corresponding to the format string
+ * @ret wlen		Length of formatted string (in wide characters)
+ */
+int efi_vssnprintf ( wchar_t *wbuf, ssize_t swsize, const char *fmt,
+		     va_list args ) {
+
+	/* Treat negative buffer size as zero buffer size */
+	if ( swsize < 0 )
+		swsize = 0;
+
+	/* Hand off to vsnprintf */
+	return efi_vsnprintf ( wbuf, swsize, fmt, args );
+}
+
+/**
+ * Version of efi_vsnprintf() that accepts a signed buffer size
+ *
+ * @v wbuf		Buffer into which to write the string
+ * @v swsize		Size of buffer (in wide characters)
+ * @v fmt		Format string
+ * @v ...		Arguments corresponding to the format string
+ * @ret wlen		Length of formatted string (in wide characters)
+ */
+int efi_ssnprintf ( wchar_t *wbuf, ssize_t swsize, const char *fmt, ... ) {
+	va_list args;
+	int len;
+
+	/* Hand off to vssnprintf */
+	va_start ( args, fmt );
+	len = efi_vssnprintf ( wbuf, swsize, fmt, args );
+	va_end ( args );
+	return len;
+}