[efi] Add efi_asprintf() and efi_vasprintf()

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

src/image/efi_image.c

@@ -109,18 +109,14 @@ efi_image_path ( struct image *image, EFI_DEVICE_PATH_PROTOCOL *parent ) {
  */
 static wchar_t * efi_image_cmdline ( struct image *image ) {
 	wchar_t *cmdline;
-	size_t len;
 
-	len = ( strlen ( image->name ) +
+	/* Allocate and construct command line */
-		( image->cmdline ?
+	if ( efi_asprintf ( &cmdline, "%s%s%s", image->name,
-		  ( 1 /* " " */ + strlen ( image->cmdline ) ) : 0 ) );
+			    ( image->cmdline ? " " : "" ),
-	cmdline = zalloc ( ( len + 1 /* NUL */ ) * sizeof ( wchar_t ) );
+			    ( image->cmdline ? image->cmdline : "" ) ) < 0 ) {
-	if ( ! cmdline )
 		return NULL;
-	efi_snprintf ( cmdline, ( len + 1 /* NUL */ ), "%s%s%s",
+	}
-		       image->name,
+
-		       ( image->cmdline ? " " : "" ),
-		       ( image->cmdline ? image->cmdline : "" ) );
 	return cmdline;
 }
 

src/include/ipxe/efi/efi_strings.h

@@ -19,6 +19,8 @@ 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, ... );
+extern int efi_vasprintf ( wchar_t **strp, const char *fmt, va_list args );
+extern int efi_asprintf ( wchar_t **strp, const char *fmt, ... );
 
 /**
  * Write a formatted string to a wide-character buffer

src/include/ipxe/errfile.h

@@ -78,6 +78,7 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
 #define ERRFILE_dma		       ( ERRFILE_CORE | 0x00260000 )
 #define ERRFILE_cachedhcp	       ( ERRFILE_CORE | 0x00270000 )
 #define ERRFILE_acpimac		       ( ERRFILE_CORE | 0x00280000 )
+#define ERRFILE_efi_strings	       ( ERRFILE_CORE | 0x00290000 )
 
 #define ERRFILE_eisa		     ( ERRFILE_DRIVER | 0x00000000 )
 #define ERRFILE_isa		     ( ERRFILE_DRIVER | 0x00010000 )

src/interface/efi/efi_strings.c

@@ -25,6 +25,8 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
 
 #include <stddef.h>
 #include <stdarg.h>
+#include <stdlib.h>
+#include <errno.h>
 #include <ipxe/vsprintf.h>
 #include <ipxe/efi/efi_strings.h>
 
@@ -150,3 +152,45 @@ int efi_ssnprintf ( wchar_t *wbuf, ssize_t swsize, const char *fmt, ... ) {
 	va_end ( args );
 	return len;
 }
+
+/**
+ * Write a formatted string to newly allocated memory
+ *
+ * @v wstrp		Pointer to hold allocated string
+ * @v fmt		Format string
+ * @v args		Arguments corresponding to the format string
+ * @ret len		Length of formatted string (in wide characters)
+ */
+int efi_vasprintf ( wchar_t **wstrp, const char *fmt, va_list args ) {
+	size_t len;
+	va_list args_tmp;
+
+	/* Calculate length needed for string */
+	va_copy ( args_tmp, args );
+	len = ( efi_vsnprintf ( NULL, 0, fmt, args_tmp ) + 1 );
+	va_end ( args_tmp );
+
+	/* Allocate and fill string */
+	*wstrp = malloc ( len * sizeof ( **wstrp ) );
+	if ( ! *wstrp )
+		return -ENOMEM;
+	return efi_vsnprintf ( *wstrp, len, fmt, args );
+}
+
+/**
+ * Write a formatted string to newly allocated memory
+ *
+ * @v wstrp		Pointer to hold allocated string
+ * @v fmt		Format string
+ * @v ...		Arguments corresponding to the format string
+ * @ret len		Length of formatted string (in wide characters)
+ */
+int efi_asprintf ( wchar_t **wstrp, const char *fmt, ... ) {
+	va_list args;
+	int len;
+
+	va_start ( args, fmt );
+	len = efi_vasprintf ( wstrp, fmt, args );
+	va_end ( args );
+	return len;
+}