efi_loader: fix efi_convert_device_node_to_text

We need to implement to different functions for the
EFI_DEVICE_PATH_TO_TEXT_PROTOCOL:
ConvertDeviceNodeToText
ConvertDevicePathToText

A recent patch screwed up efi_convert_device_node_to_text
to expect a device path and not a node.

The patch makes both service functions work again.

efi_convert_device_node_to_text is renamed to
efi_convert_single_device_node_to_text and
efi_convert_device_node_to_text_ext is renamed to
efi_convert_device_node_to_text to avoid future
confusion.

A test of ConvertDeviceNodeToText will be provided in
a follow-up patch.

Fixes: adae4313 efi_loader: flesh out device-path to text
Signed-off-by: NHeinrich Schuchardt <xypron.glpk@gmx.de>
Signed-off-by: NAlexander Graf <agraf@suse.de>

lib/efi_loader/efi_device_path_to_text.c

@@ -12,12 +12,31 @@
 #define MAC_OUTPUT_LEN 22
 #define UNKNOWN_OUTPUT_LEN 23
 
+#define MAX_NODE_LEN 512
+#define MAX_PATH_LEN 1024
+
 const efi_guid_t efi_guid_device_path_to_text_protocol =
 		EFI_DEVICE_PATH_TO_TEXT_PROTOCOL_GUID;
 
+static u16 *efi_str_to_u16(char *str)
+{
+	efi_uintn_t len;
+	u16 *out;
+	efi_status_t ret;
+
+	len = strlen(str) + 1;
+	ret = efi_allocate_pool(EFI_ALLOCATE_ANY_PAGES, len * sizeof(u16),
+				(void **)&out);
+	if (ret != EFI_SUCCESS)
+		return NULL;
+	ascii2unicode(out, str);
+	out[len - 1] = 0;
+	return out;
+}
+
 static char *dp_unknown(char *s, struct efi_device_path *dp)
 {
-	s += sprintf(s, "/UNKNOWN(%04x,%04x)", dp->type, dp->sub_type);
+	s += sprintf(s, "UNKNOWN(%04x,%04x)", dp->type, dp->sub_type);
 	return s;
 }
 
@@ -27,7 +46,7 @@ static char *dp_hardware(char *s, struct efi_device_path *dp)
 	case DEVICE_PATH_SUB_TYPE_MEMORY: {
 		struct efi_device_path_memory *mdp =
 			(struct efi_device_path_memory *)dp;
-		s += sprintf(s, "/MemoryMapped(0x%x,0x%llx,0x%llx)",
+		s += sprintf(s, "MemoryMapped(0x%x,0x%llx,0x%llx)",
 			     mdp->memory_type,
 			     mdp->start_address,
 			     mdp->end_address);
@@ -36,7 +55,7 @@ static char *dp_hardware(char *s, struct efi_device_path *dp)
 	case DEVICE_PATH_SUB_TYPE_VENDOR: {
 		struct efi_device_path_vendor *vdp =
 			(struct efi_device_path_vendor *)dp;
-		s += sprintf(s, "/VenHw(%pUl)", &vdp->guid);
+		s += sprintf(s, "VenHw(%pUl)", &vdp->guid);
 		break;
 	}
 	default:
@@ -52,7 +71,7 @@ static char *dp_acpi(char *s, struct efi_device_path *dp)
 	case DEVICE_PATH_SUB_TYPE_ACPI_DEVICE: {
 		struct efi_device_path_acpi_path *adp =
 			(struct efi_device_path_acpi_path *)dp;
-		s += sprintf(s, "/Acpi(PNP%04x", EISA_PNP_NUM(adp->hid));
+		s += sprintf(s, "Acpi(PNP%04x", EISA_PNP_NUM(adp->hid));
 		if (adp->uid)
 			s += sprintf(s, ",%d", adp->uid);
 		s += sprintf(s, ")");
@@ -71,7 +90,7 @@ static char *dp_msging(char *s, struct efi_device_path *dp)
 	case DEVICE_PATH_SUB_TYPE_MSG_USB: {
 		struct efi_device_path_usb *udp =
 			(struct efi_device_path_usb *)dp;
-		s += sprintf(s, "/Usb(0x%x,0x%x)", udp->parent_port_number,
+		s += sprintf(s, "Usb(0x%x,0x%x)", udp->parent_port_number,
 			     udp->usb_interface);
 		break;
 	}
@@ -82,7 +101,7 @@ static char *dp_msging(char *s, struct efi_device_path *dp)
 		if (mdp->if_type != 0 && mdp->if_type != 1)
 			break;
 
-		s += sprintf(s, "/MAC(%02x%02x%02x%02x%02x%02x,0x%1x)",
+		s += sprintf(s, "MAC(%02x%02x%02x%02x%02x%02x,0x%1x)",
 			mdp->mac.addr[0], mdp->mac.addr[1],
 			mdp->mac.addr[2], mdp->mac.addr[3],
 			mdp->mac.addr[4], mdp->mac.addr[5],
@@ -94,7 +113,7 @@ static char *dp_msging(char *s, struct efi_device_path *dp)
 		struct efi_device_path_usb_class *ucdp =
 			(struct efi_device_path_usb_class *)dp;
 
-		s += sprintf(s, "/USBClass(%x,%x,%x,%x,%x)",
+		s += sprintf(s, "USBClass(%x,%x,%x,%x,%x)",
 			ucdp->vendor_id, ucdp->product_id,
 			ucdp->device_class, ucdp->device_subclass,
 			ucdp->device_protocol);
@@ -108,7 +127,7 @@ static char *dp_msging(char *s, struct efi_device_path *dp)
 					"SDCard" : "MMC";
 		struct efi_device_path_sd_mmc_path *sddp =
 			(struct efi_device_path_sd_mmc_path *)dp;
-		s += sprintf(s, "/%s(Slot%u)", typename, sddp->slot_number);
+		s += sprintf(s, "%s(Slot%u)", typename, sddp->slot_number);
 		break;
 	}
 	default:
@@ -128,15 +147,15 @@ static char *dp_media(char *s, struct efi_device_path *dp)
 
 		switch (hddp->signature_type) {
 		case SIG_TYPE_MBR:
-			s += sprintf(s, "/HD(Part%d,Sig%08x)",
+			s += sprintf(s, "HD(Part%d,Sig%08x)",
 				     hddp->partition_number,
 				     *(uint32_t *)sig);
 			break;
 		case SIG_TYPE_GUID:
-			s += sprintf(s, "/HD(Part%d,Sig%pUl)",
+			s += sprintf(s, "HD(Part%d,Sig%pUl)",
 				     hddp->partition_number, sig);
 		default:
-			s += sprintf(s, "/HD(Part%d,MBRType=%02x,SigType=%02x)",
+			s += sprintf(s, "HD(Part%d,MBRType=%02x,SigType=%02x)",
 				     hddp->partition_number, hddp->partmap_type,
 				     hddp->signature_type);
 		}
@@ -146,14 +165,16 @@ static char *dp_media(char *s, struct efi_device_path *dp)
 	case DEVICE_PATH_SUB_TYPE_CDROM_PATH: {
 		struct efi_device_path_cdrom_path *cddp =
 			(struct efi_device_path_cdrom_path *)dp;
-		s += sprintf(s, "/CDROM(0x%x)", cddp->boot_entry);
+		s += sprintf(s, "CDROM(0x%x)", cddp->boot_entry);
 		break;
 	}
 	case DEVICE_PATH_SUB_TYPE_FILE_PATH: {
 		struct efi_device_path_file_path *fp =
 			(struct efi_device_path_file_path *)dp;
 		int slen = (dp->length - sizeof(*dp)) / 2;
-		s += sprintf(s, "/%-.*ls", slen, fp->str);
+		if (slen > MAX_NODE_LEN - 2)
+			slen = MAX_NODE_LEN - 2;
+		s += sprintf(s, "%-.*ls", slen, fp->str);
 		break;
 	}
 	default:
@@ -163,65 +184,59 @@ static char *dp_media(char *s, struct efi_device_path *dp)
 	return s;
 }
 
-static uint16_t *efi_convert_device_node_to_text(
-		struct efi_device_path *dp,
-		bool display_only,
-		bool allow_shortcuts)
+/*
+ * Converts a single node to a char string.
+ *
+ * @buffer		output buffer
+ * @dp			device path or node
+ * @return		end of string
+ */
+static char *efi_convert_single_device_node_to_text(
+		char *buffer,
+		struct efi_device_path *dp)
 {
-	unsigned long len;
-	efi_status_t r;
-	char buf[512];  /* this ought be be big enough for worst case */
-	char *str = buf;
-	uint16_t *out;
-
-	while (dp) {
-		switch (dp->type) {
-		case DEVICE_PATH_TYPE_HARDWARE_DEVICE:
-			str = dp_hardware(str, dp);
-			break;
-		case DEVICE_PATH_TYPE_ACPI_DEVICE:
-			str = dp_acpi(str, dp);
-			break;
-		case DEVICE_PATH_TYPE_MESSAGING_DEVICE:
-			str = dp_msging(str, dp);
-			break;
-		case DEVICE_PATH_TYPE_MEDIA_DEVICE:
-			str = dp_media(str, dp);
-			break;
-		default:
-			str = dp_unknown(str, dp);
-		}
+	char *str = buffer;
 
-		dp = efi_dp_next(dp);
+	switch (dp->type) {
+	case DEVICE_PATH_TYPE_HARDWARE_DEVICE:
+		str = dp_hardware(str, dp);
+		break;
+	case DEVICE_PATH_TYPE_ACPI_DEVICE:
+		str = dp_acpi(str, dp);
+		break;
+	case DEVICE_PATH_TYPE_MESSAGING_DEVICE:
+		str = dp_msging(str, dp);
+		break;
+	case DEVICE_PATH_TYPE_MEDIA_DEVICE:
+		str = dp_media(str, dp);
+		break;
+	default:
+		str = dp_unknown(str, dp);
 	}
 
-	*str++ = '\0';
-
-	len = str - buf;
-	r = efi_allocate_pool(EFI_ALLOCATE_ANY_PAGES, 2 * len, (void **)&out);
-	if (r != EFI_SUCCESS)
-		return NULL;
-
-	ascii2unicode(out, buf);
-	out[len - 1] = 0;
-
-	return out;
+	*str = '\0';
+	return str;
 }
 
-static uint16_t EFIAPI *efi_convert_device_node_to_text_ext(
+static uint16_t EFIAPI *efi_convert_device_node_to_text(
 		struct efi_device_path *device_node,
 		bool display_only,
 		bool allow_shortcuts)
 {
-	uint16_t *buffer;
+	char str[MAX_NODE_LEN];
+	uint16_t *text = NULL;
 
 	EFI_ENTRY("%p, %d, %d", device_node, display_only, allow_shortcuts);
 
-	buffer = efi_convert_device_node_to_text(device_node, display_only,
-						 allow_shortcuts);
+	if (!device_node)
+		goto out;
+	efi_convert_single_device_node_to_text(str, device_node);
+
+	text = efi_str_to_u16(str);
 
+out:
 	EFI_EXIT(EFI_SUCCESS);
-	return buffer;
+	return text;
 }
 
 static uint16_t EFIAPI *efi_convert_device_path_to_text(
@@ -229,19 +244,26 @@ static uint16_t EFIAPI *efi_convert_device_path_to_text(
 		bool display_only,
 		bool allow_shortcuts)
 {
-	uint16_t *buffer;
+	uint16_t *text = NULL;
+	char buffer[MAX_PATH_LEN];
+	char *str = buffer;
 
 	EFI_ENTRY("%p, %d, %d", device_path, display_only, allow_shortcuts);
 
-	/*
-	 * Our device paths are all of depth one. So its is sufficient to
-	 * to convert the first node.
-	 */
-	buffer = efi_convert_device_node_to_text(device_path, display_only,
-						 allow_shortcuts);
+	if (!device_path)
+		goto out;
+	while (device_path &&
+	       str + MAX_NODE_LEN < buffer + MAX_PATH_LEN) {
+		*str++ = '/';
+		str = efi_convert_single_device_node_to_text(str, device_path);
+		device_path = efi_dp_next(device_path);
+	}
+
+	text = efi_str_to_u16(buffer);
 
+out:
 	EFI_EXIT(EFI_SUCCESS);
-	return buffer;
+	return text;
 }
 
 /* helper for debug prints.. efi_free_pool() the result. */
@@ -251,6 +273,6 @@ uint16_t *efi_dp_str(struct efi_device_path *dp)
 }
 
 const struct efi_device_path_to_text_protocol efi_device_path_to_text = {
-	.convert_device_node_to_text = efi_convert_device_node_to_text_ext,
+	.convert_device_node_to_text = efi_convert_device_node_to_text,
 	.convert_device_path_to_text = efi_convert_device_path_to_text,
 };