commit disk before free

When auto-freeing a disk, be sure to commit pending changes first.

fixes setActiveBootslot() since the GPT refactor

Signed-off-by: Caleb Connolly <caleb.connolly@linaro.org>

bootctrl.h

@@ -51,8 +51,9 @@ struct boot_control_module {
 	* The returned value is always guaranteed to be strictly less than the
 	* value returned by getNumberSlots. Slots start at 0 and
 	* finish at getNumberSlots() - 1
+	* Returns -ENOENT on devices with no slots.
 	*/
-	unsigned (*getCurrentSlot)();
+	int (*getCurrentSlot)();
 
 	/*
 	* (*markBootSuccessful)() marks the specified slot

bootctrl_impl.c

@@ -331,21 +331,50 @@ int get_boot_attr(struct gpt_disk *disk, unsigned slot, enum part_attr_type attr
 	return get_partition_attribute(disk, bootPartition, attr);
 }
 
-static unsigned int get_current_slot_from_kernel_cmdline()
+unsigned get_active_boot_slot()
 {
-	uint32_t num_slots = 0;
-	char bootSlotProp[MAX_CMDLINE_SIZE] = { '\0' };
-	unsigned i = 0;
-	num_slots = get_number_slots();
+	struct gpt_disk disk = { 0 };
+	uint32_t num_slots = get_number_slots();
+
 	if (num_slots <= 1) {
 		// Slot 0 is the only slot around.
 		return 0;
 	}
 
-	get_kernel_cmdline_arg(BOOT_SLOT_PROP, bootSlotProp, "_a");
+	for (uint32_t i = 0; i < num_slots; i++) {
+		if (get_boot_attr(&disk, i, ATTR_SLOT_ACTIVE)) {
+			gpt_disk_free(&disk);
+			return i;
+		}
+	}
+
+	fprintf(stderr, "%s: Failed to find the active boot slot\n", __func__);
+	gpt_disk_free(&disk);
+	return 0;
+}
+
+/*
+ * The current slot is usually made available via the kernel cmdline. If it isn't for some reason
+ * (e.g. because we booted via a secondary bootloader that removes Android cmdline args) then we
+ * assume that the active slot is the current slot
+ */
+static int get_current_or_active_slot()
+{
+	uint32_t num_slots = 0;
+	char bootSlotProp[MAX_CMDLINE_SIZE] = { '\0' };
+	unsigned i = 0;
+	num_slots = get_number_slots();
+	if (num_slots == 0)
+		return -ENOENT;
+	if (num_slots == 1) {
+		// Slot 0 is the only slot around.
+		return 0;
+	}
+
+	get_kernel_cmdline_arg(BOOT_SLOT_PROP, bootSlotProp, "N/A");
 	if (!strncmp(bootSlotProp, "N/A\n", strlen("N/A"))) {
 		fprintf(stderr, "%s: Unable to read boot slot property\n", __func__);
-		return 0;
+		return get_active_boot_slot();
 	}
 
 	// Iterate through a list of partitons named as boot+suffix
@@ -538,28 +567,6 @@ static int boot_ctl_set_active_slot_for_partitions(struct gpt_disk *disk,
 	return 0;
 }
 
-unsigned get_active_boot_slot()
-{
-	struct gpt_disk disk = { 0 };
-	uint32_t num_slots = get_number_slots();
-
-	if (num_slots <= 1) {
-		// Slot 0 is the only slot around.
-		return 0;
-	}
-
-	for (uint32_t i = 0; i < num_slots; i++) {
-		if (get_boot_attr(&disk, i, ATTR_SLOT_ACTIVE)) {
-			gpt_disk_free(&disk);
-			return i;
-		}
-	}
-
-	fprintf(stderr, "%s: Failed to find the active boot slot\n", __func__);
-	gpt_disk_free(&disk);
-	return 0;
-}
-
 int set_active_boot_slot(unsigned slot, bool ignore_missing_bsg)
 {
 	enum boot_chain chain = (enum boot_chain)slot;
@@ -638,7 +645,7 @@ int is_slot_marked_successful(unsigned slot)
 }
 
 const struct boot_control_module bootctl = {
-	.getCurrentSlot = get_current_slot_from_kernel_cmdline,
+	.getCurrentSlot = get_current_or_active_slot,
 	.markBootSuccessful = mark_boot_successful,
 	.setActiveBootSlot = set_active_boot_slot,
 	.setSlotAsUnbootable = set_slot_as_unbootable,

gpt-utils.c

@@ -403,7 +403,7 @@ static int gpt_get_headers(const char *partname, uint8_t **primary, uint8_t **ba
 		goto error;
 	}
 
-	fd = open(devpath, O_RDWR);
+	fd = open(devpath, O_RDONLY);
 	if (fd < 0) {
 		fprintf(stderr, "%s: Failed to open %s : %s\n", __func__, devpath, strerror(errno));
 		return -1;
@@ -613,6 +613,11 @@ int gpt_disk_get_disk_info(const char *dev, struct gpt_disk *disk)
 	}
 
 	if (disk->is_initialized == GPT_DISK_INIT_MAGIC) {
+		/* Commit any changes to the disk */
+		if (gpt_disk_commit(disk)) {
+			fprintf(stderr, "Failed to commit disk entry");
+			return -1;
+		}
 		// We already have a valid disk handle. Free it.
 		LOGD("%s: Freeing disk handle for %s... -> %s\n", __func__, disk->devpath, devpath);
 		gpt_disk_free(disk);
@@ -638,7 +643,7 @@ int gpt_disk_get_disk_info(const char *dev, struct gpt_disk *disk)
 
 	disk->hdr_bak_crc = efi_crc32(disk->hdr_bak, gpt_header_size);
 
-	fd = open(disk->devpath, O_RDWR);
+	fd = open(disk->devpath, O_RDONLY);
 	if (fd < 0) {
 		fprintf(stderr, "%s: Failed to open %s: %s\n", __func__, disk->devpath,
 			strerror(errno));

qbootctl.c

@@ -115,10 +115,9 @@ int get_slot_info(struct slot_info *slots)
 	return 0;
 }
 
-void dump_info()
+static void dump_info(int current_slot)
 {
 	struct slot_info slots[2] = { { 0 } };
-	int current_slot = impl->getCurrentSlot();
 
 	get_slot_info(slots);
 
@@ -135,7 +134,7 @@ void dump_info()
 int main(int argc, char **argv)
 {
 	int optflag;
-	int slot = -1;
+	int slot = -1, current_slot;
 	int rc;
 	bool ignore_missing_bsg = false;
 
@@ -144,9 +143,15 @@ int main(int argc, char **argv)
 		return 1;
 	}
 
+	current_slot = impl->getCurrentSlot();
+	if (current_slot < 0) {
+		fprintf(stderr, "No slots found, is this an A/B device?\n");
+		return 1;
+	}
+
 	switch (argc) {
 	case 1:
-		dump_info();
+		dump_info(current_slot);
 		return 0;
 	case 2:
 		break;
@@ -157,14 +162,13 @@ int main(int argc, char **argv)
 		return usage();
 	}
 
-	if (slot < 0)
-		slot = impl->getCurrentSlot();
-
 	optflag = getopt(argc, argv, "hcmas:ub:n:x");
 
+	if (slot < 0 || optflag == 'c')
+		slot = current_slot;
+
 	switch (optflag) {
 	case 'c':
-		slot = impl->getCurrentSlot();
 		printf("Current slot: %s\n", impl->getSuffix(slot));
 		return 0;
 	case 'a':