fastboot: implement "getvar all"

This commit implements "fastboot getvar all" listing
by iterating the existing dispatchers that don't require
parameters (as we pass NULL), uses fastboot multiresponse.

Signed-off-by: Ion Agorria <ion@agorria.com>
Signed-off-by: Svyatoslav Ryhel <clamor95@gmail.com>
Reviewed-by: Mattijs Korpershoek <mkorpershoek@baylibre.com>
Link: https://lore.kernel.org/r/20240105072212.6615-3-clamor95@gmail.com
Signed-off-by: Mattijs Korpershoek <mkorpershoek@baylibre.com>

doc/android/fastboot-protocol.rst

@@ -173,6 +173,9 @@ The various currently defined names are::
                       bootloader requiring a signature before
                       it will install or boot images.
 
+  all                 Provides all info from commands above as
+                      they were called one by one
+
 Names starting with a lowercase character are reserved by this
 specification.  OEM-specific names should not start with lowercase
 characters.

drivers/fastboot/fb_command.c

@@ -156,6 +156,9 @@ int fastboot_handle_command(char *cmd_string, char *response)
 void fastboot_multiresponse(int cmd, char *response)
 {
 	switch (cmd) {
+	case FASTBOOT_COMMAND_GETVAR:
+		fastboot_getvar_all(response);
+		break;
 	default:
 		fastboot_fail("Unknown multiresponse command", response);
 		break;

drivers/fastboot/fb_getvar.c

@@ -29,53 +29,67 @@ static void getvar_is_userspace(char *var_parameter, char *response);
 
 static const struct {
 	const char *variable;
+	bool list;
 	void (*dispatch)(char *var_parameter, char *response);
 } getvar_dispatch[] = {
 	{
 		.variable = "version",
-		.dispatch = getvar_version
+		.dispatch = getvar_version,
+		.list = true,
 	}, {
 		.variable = "version-bootloader",
-		.dispatch = getvar_version_bootloader
+		.dispatch = getvar_version_bootloader,
+		.list = true
 	}, {
 		.variable = "downloadsize",
-		.dispatch = getvar_downloadsize
+		.dispatch = getvar_downloadsize,
+		.list = true
 	}, {
 		.variable = "max-download-size",
-		.dispatch = getvar_downloadsize
+		.dispatch = getvar_downloadsize,
+		.list = true
 	}, {
 		.variable = "serialno",
-		.dispatch = getvar_serialno
+		.dispatch = getvar_serialno,
+		.list = true
 	}, {
 		.variable = "version-baseband",
-		.dispatch = getvar_version_baseband
+		.dispatch = getvar_version_baseband,
+		.list = true
 	}, {
 		.variable = "product",
-		.dispatch = getvar_product
+		.dispatch = getvar_product,
+		.list = true
 	}, {
 		.variable = "platform",
-		.dispatch = getvar_platform
+		.dispatch = getvar_platform,
+		.list = true
 	}, {
 		.variable = "current-slot",
-		.dispatch = getvar_current_slot
+		.dispatch = getvar_current_slot,
+		.list = true
 #if IS_ENABLED(CONFIG_FASTBOOT_FLASH)
 	}, {
 		.variable = "has-slot",
-		.dispatch = getvar_has_slot
+		.dispatch = getvar_has_slot,
+		.list = false
 #endif
 #if IS_ENABLED(CONFIG_FASTBOOT_FLASH_MMC)
 	}, {
 		.variable = "partition-type",
-		.dispatch = getvar_partition_type
+		.dispatch = getvar_partition_type,
+		.list = false
 #endif
 #if IS_ENABLED(CONFIG_FASTBOOT_FLASH)
 	}, {
 		.variable = "partition-size",
-		.dispatch = getvar_partition_size
+		.dispatch = getvar_partition_size,
+		.list = false
 #endif
 	}, {
 		.variable = "is-userspace",
-		.dispatch = getvar_is_userspace
+		.dispatch = getvar_is_userspace,
+		.list = true
 	}
 };
 
@@ -237,6 +251,40 @@ static void getvar_is_userspace(char *var_parameter, char *response)
 	fastboot_okay("no", response);
 }
 
+static int current_all_dispatch;
+void fastboot_getvar_all(char *response)
+{
+	/*
+	 * Find a dispatch getvar that can be listed and send
+	 * it as INFO until we reach the end.
+	 */
+	while (current_all_dispatch < ARRAY_SIZE(getvar_dispatch)) {
+		if (!getvar_dispatch[current_all_dispatch].list) {
+			current_all_dispatch++;
+			continue;
+		}
+
+		char envstr[FASTBOOT_RESPONSE_LEN] = { 0 };
+
+		getvar_dispatch[current_all_dispatch].dispatch(NULL, envstr);
+
+		char *envstr_start = envstr;
+
+		if (!strncmp("OKAY", envstr, 4) || !strncmp("FAIL", envstr, 4))
+			envstr_start += 4;
+
+		fastboot_response("INFO", response, "%s: %s",
+				  getvar_dispatch[current_all_dispatch].variable,
+				  envstr_start);
+
+		current_all_dispatch++;
+		return;
+	}
+
+	fastboot_response("OKAY", response, NULL);
+	current_all_dispatch = 0;
+}
+
 /**
  * fastboot_getvar() - Writes variable indicated by cmd_parameter to response.
  *
@@ -254,6 +302,9 @@ void fastboot_getvar(char *cmd_parameter, char *response)
 {
 	if (!cmd_parameter) {
 		fastboot_fail("missing var", response);
+	} else if (!strncmp("all", cmd_parameter, 3) && strlen(cmd_parameter) == 3) {
+		current_all_dispatch = 0;
+		fastboot_response(FASTBOOT_MULTIRESPONSE_START, response, NULL);
 	} else {
 #define FASTBOOT_ENV_PREFIX	"fastboot."
 		int i;

include/fastboot-internal.h

@@ -18,6 +18,13 @@ extern u32 fastboot_buf_size;
  */
 extern void (*fastboot_progress_callback)(const char *msg);
 
+/**
+ * fastboot_getvar_all() - Writes current variable being listed from "all" to response.
+ *
+ * @response: Pointer to fastboot response buffer
+ */
+void fastboot_getvar_all(char *response);
+
 /**
  * fastboot_getvar() - Writes variable indicated by cmd_parameter to response.
  *