Initial import

The PIT was taken from the Replicant data repository[1].
[1]https://git.replicant.us/replicant/vendor_replicant-data.git

Signed-off-by: Denis 'GNUtoo' Carikli <GNUtoo@cyberdimension.org>

1 files changed, 226 insertions, 0 deletions

diff --git a/main.c b/main.c
new file mode 100644
index 0000000..afdea28
--- /dev/null
+++ b/main.c
@@ -0,0 +1,226 @@
+/*
+ * Copyright (C) 2022 Denis 'GNUtoo' Carikli <GNUtoo@cyberdimension.org>
+ *
+ * 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 3 of the License, or
+ * (at your option) 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, see <https://www.gnu.org/licenses/>.
+ */
+
+#include <endian.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include <sys/mman.h>
+
+struct pit_partition_v2 {
+	uint32_t binary_type;
+	uint32_t device_type;
+	uint32_t partition_id;
+	uint32_t partition_type;
+	uint32_t file_system;
+	uint32_t start_block;
+	uint32_t nr_blocks;
+	uint32_t file_offset;
+	uint32_t file_size;
+	char name[32];
+	char file_name[32];
+	char fota_name[32];
+} __attribute__((__packed__));
+
+int hexdump(void *buffer, size_t buffer_len, size_t offset, size_t len)
+{
+	char* b = buffer + offset;
+
+	if (len == 1)
+		printf("0x%x\n", *b);
+}
+
+
+size_t find_partition(void *buffer, size_t buffer_len,
+		      char *name)
+{
+	off_t offset = 0;
+	int found;
+
+	/* Entries begin after first 28 bytes[1].
+	 * [1]https://samsung-loki.github.io/samsung-docs/docs/PIT/
+	 */
+	offset += 28;
+	if (buffer_len < offset)
+		return -1;
+
+	do {
+		struct pit_partition_v2 *partition;
+
+		if (buffer_len < offset + sizeof(struct pit_partition_v2))
+			return -1;
+		partition = buffer + offset;
+		printf("%s: found %s\n", __func__, partition->name);
+		found = !strncmp(name, partition->name, strlen(name));
+		if (found)
+			return offset;
+		else
+			offset += sizeof(struct pit_partition_v2);
+	} while(!found);
+
+	return -1;
+}
+
+size_t find_next_partition(void *buffer,
+			   size_t buffer_size,
+			   size_t offset)
+{
+	struct pit_partition_v2 *partition;
+
+	size_t start_offset = 28;
+	size_t part_size = sizeof(struct pit_partition_v2);
+
+	if (offset > 28) {
+		uint32_t nr_prev_partitions = ((offset - 28) / part_size);
+		if ((offset - 28) % part_size)
+			start_offset += ((nr_prev_partitions + 1) * part_size);
+		else
+			start_offset += (nr_prev_partitions * part_size);
+	}
+
+	if (buffer_size < (start_offset + part_size))
+		return -1;
+
+	return start_offset + part_size;
+}
+
+int grow_partition(void *buffer, size_t buffer_size, char *name,
+		   size_t extra_bytes)
+{
+	struct pit_partition_v2 *partition;
+	size_t offset;
+	size_t partition_nr_blocks;
+	size_t nr_extra_blocks;
+
+	if (extra_bytes % 512)
+		nr_extra_blocks = extra_bytes / 512;
+	else
+		nr_extra_blocks = (extra_bytes / 512) + 1;
+
+	offset = find_partition(buffer, buffer_size, name);
+	if (offset == -1) {
+		printf("%s: \"%s\" partition not found\n",
+		       __func__, name);
+	}
+	partition = buffer + offset;
+
+	printf("%s: growing \"%s\" from %d to %d blocks\n",
+	       __func__, partition->name,
+	       le32toh(partition->nr_blocks),
+	       le32toh(partition->nr_blocks) + nr_extra_blocks);
+	partition_nr_blocks = le32toh(partition->nr_blocks) + nr_extra_blocks;
+	partition->nr_blocks = htole32(partition_nr_blocks);
+
+	do {
+		size_t new_offset = 0;
+
+		offset = find_next_partition(buffer, buffer_size, offset);
+		if (offset == -1)
+			break;
+
+		partition = buffer + offset;
+
+		if (partition->nr_blocks == 0)
+			continue;
+
+		new_offset = le32toh(partition->start_block) + nr_extra_blocks;
+
+		printf("%s: moving \"%s\" from 0x%x to 0x%x\n",
+		       __func__,
+		       partition->name,
+		       le32toh(partition->start_block),
+		       new_offset);
+		partition->start_block = new_offset;
+	}
+	while (true);
+
+	return 0;
+}
+
+int main()
+{
+	int fd;
+	int rc;
+
+	void *orig;
+	off_t orig_size;
+	off_t offset;
+
+	fd = open("16G.pit", O_RDWR);
+	if (fd == -1) {
+		rc = errno;
+		printf("%s: open failed with error %d: %s\n",
+		       __func__, rc, strerror(rc));
+		return rc;
+	}
+
+	offset = lseek(fd, 0, SEEK_END);
+	if (offset == -1) {
+		rc = errno;
+		printf("%s: lseek to SEEK_END failed with error %d: %s\n",
+		       __func__, rc, strerror(rc));
+		return rc;
+	}
+
+	orig_size = offset;
+	offset = lseek(fd, 0, SEEK_SET);
+	if (offset == -1) {
+		rc = errno;
+		printf("%s: lseek to 0 failed with error %d: %s\n",
+		       __func__, rc, strerror(rc));
+		return rc;
+	}
+
+	orig = mmap(NULL, orig_size, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
+	if (orig == MAP_FAILED) {
+		rc = errno;
+		printf("%s: mmap failed with error %d: %s\n",
+		       __func__, rc, strerror(rc));
+		return rc;
+	}
+
+	rc = grow_partition(orig, orig_size, "FACTORYFS", 512*1024*1024);
+	if (rc == -1) {
+		printf("%s: modify_partitions failed with error %d\n",
+		       __func__, rc);
+		return rc;
+	}
+
+	rc = munmap(orig, orig_size);
+	if (rc == -1) {
+		rc = errno;
+		printf("%s: munmap failed with error %d: %s\n",
+		       __func__, rc, strerror(rc));
+		return rc;
+	}
+
+	rc = close(fd);
+	if (rc == -1) {
+		rc = errno;
+		printf("%s: close failed with error %d: %s\n",
+		       __func__, rc, strerror(rc));
+		return rc;
+	}
+	printf("DONE\n");
+}