fdisk: initial stab at GPT partition support

Signed-off-by: Kevin Cernekee <cernekee@gmail.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 203 insertions, 0 deletions

diff --git a/util-linux/fdisk_gpt.c b/util-linux/fdisk_gpt.c
new file mode 100644
index 000000000..98803ec88
--- /dev/null
+++ b/util-linux/fdisk_gpt.c
@@ -0,0 +1,203 @@
+#if ENABLE_FEATURE_GPT_LABEL
+/*
+ * Copyright (C) 2010 Kevin Cernekee <cernekee@gmail.com>
+ *
+ * Licensed under GPLv2, see file LICENSE in this source tree.
+ */
+
+#define GPT_MAGIC 0x5452415020494645ULL
+enum {
+	LEGACY_GPT_TYPE	= 0xee,
+	GPT_MAX_PARTS   = 256,
+	GPT_MAX_PART_ENTRY_LEN = 4096,
+	GUID_LEN        = 16,
+};
+
+typedef struct {
+	uint64_t magic;
+	uint32_t revision;
+	uint32_t hdr_size;
+	uint32_t hdr_crc32;
+	uint32_t reserved;
+	uint64_t current_lba;
+	uint64_t backup_lba;
+	uint64_t first_usable_lba;
+	uint64_t last_usable_lba;
+	uint8_t  disk_guid[GUID_LEN];
+	uint64_t first_part_lba;
+	uint32_t n_parts;
+	uint32_t part_entry_len;
+	uint32_t part_array_crc32;
+} gpt_header;
+
+typedef struct {
+	uint8_t  type_guid[GUID_LEN];
+	uint8_t  part_guid[GUID_LEN];
+	uint64_t lba_start;
+	uint64_t lba_end;
+	uint64_t flags;
+	uint16_t name[36];
+} gpt_partition;
+
+static gpt_header *gpt_hdr;
+
+static char *part_array;
+static unsigned int n_parts;
+static unsigned int part_array_len;
+static unsigned int part_entry_len;
+
+static uint32_t *crc32_table;
+
+static inline gpt_partition *
+gpt_part(int i)
+{
+	if (i >= n_parts) {
+		return NULL;
+	}
+	return (gpt_partition *)&part_array[i * part_entry_len];
+}
+
+/* TODO: move to libbb */
+static uint32_t
+gpt_crc32(void *buf, int len)
+{
+	uint32_t crc = 0xffffffff;
+
+	for (; len > 0; len--, buf++) {
+		crc = crc32_table[(crc ^ *((char *)buf)) & 0xff] ^ (crc >> 8);
+	}
+	return crc ^ 0xffffffff;
+}
+
+static void
+gpt_print_guid(uint8_t *buf)
+{
+	printf(
+		"%02x%02x%02x%02x-%02x%02x-%02x%02x-%02x%02x-%02x%02x%02x%02x%02x%02x",
+		buf[3], buf[2], buf[1], buf[0],
+		buf[5], buf[4],
+		buf[7], buf[6],
+		buf[8], buf[9],
+		buf[10], buf[11], buf[12], buf[13], buf[14], buf[15]);
+}
+
+/* TODO: real unicode support */
+static void
+gpt_print_wide(uint16_t *s, int max_len)
+{
+	int i = 0;
+
+	while (i < max_len) {
+		if (*s == 0)
+			return;
+		fputc(*s, stdout);
+		s++;
+	}
+}
+
+static void
+gpt_list_table(int xtra UNUSED_PARAM)
+{
+	int i;
+	char numstr6[6];
+
+	numstr6[5] = '\0';
+
+	smart_ulltoa5(total_number_of_sectors, numstr6, " KMGTPEZY");
+	printf("Disk %s: %llu sectors, %s\n", disk_device,
+		(unsigned long long)total_number_of_sectors,
+		numstr6);
+	printf("Logical sector size: %u\n", sector_size);
+	printf("Disk identifier (GUID): ");
+	gpt_print_guid(gpt_hdr->disk_guid);
+	printf("\nPartition table holds up to %u entries\n",
+		(int)SWAP_LE32(gpt_hdr->n_parts));
+	printf("First usable sector is %llu, last usable sector is %llu\n\n",
+		(unsigned long long)SWAP_LE64(gpt_hdr->first_usable_lba),
+		(unsigned long long)SWAP_LE64(gpt_hdr->last_usable_lba));
+
+	printf("Number  Start (sector)    End (sector)  Size       Code  Name\n");
+	for (i = 0; i < n_parts; i++) {
+		gpt_partition *p = gpt_part(i);
+		if (p->lba_start) {
+			smart_ulltoa5(1 + SWAP_LE64(p->lba_end) - SWAP_LE64(p->lba_start),
+				numstr6, " KMGTPEZY");
+			printf("%4u %15llu %15llu %11s   %04x  ",
+				i + 1,
+				(unsigned long long)SWAP_LE64(p->lba_start),
+				(unsigned long long)SWAP_LE64(p->lba_end),
+				numstr6,
+				0x0700 /* FIXME */);
+			gpt_print_wide(p->name, 18);
+			printf("\n");
+		}
+	}
+}
+
+static int
+check_gpt_label(void)
+{
+	struct partition *first = pt_offset(MBRbuffer, 0);
+	struct pte pe;
+	uint32_t crc;
+
+	/* LBA 0 contains the legacy MBR */
+
+	if (!valid_part_table_flag(MBRbuffer)
+	 || first->sys_ind != LEGACY_GPT_TYPE
+	) {
+		current_label_type = 0;
+		return 0;
+	}
+
+	/* LBA 1 contains the GPT header */
+
+	read_pte(&pe, 1);
+	gpt_hdr = (void *)pe.sectorbuffer;
+
+	if (gpt_hdr->magic != SWAP_LE64(GPT_MAGIC)) {
+		current_label_type = 0;
+		return 0;
+	}
+
+	if (!crc32_table) {
+		crc32_table = crc32_filltable(NULL, 0);
+	}
+
+	crc = SWAP_LE32(gpt_hdr->hdr_crc32);
+	gpt_hdr->hdr_crc32 = 0;
+	if (gpt_crc32(gpt_hdr, SWAP_LE32(gpt_hdr->hdr_size)) != crc) {
+		/* FIXME: read the backup table */
+		puts("\nwarning: GPT header CRC is invalid\n");
+	}
+
+	n_parts = SWAP_LE32(gpt_hdr->n_parts);
+	part_entry_len = SWAP_LE32(gpt_hdr->part_entry_len);
+	if (n_parts > GPT_MAX_PARTS
+	 || part_entry_len > GPT_MAX_PART_ENTRY_LEN
+	 || SWAP_LE32(gpt_hdr->hdr_size) > sector_size
+	) {
+		puts("\nwarning: unable to parse GPT disklabel\n");
+		current_label_type = 0;
+		return 0;
+	}
+
+	part_array_len = n_parts * part_entry_len;
+	part_array = xmalloc(part_array_len);
+	seek_sector(SWAP_LE64(gpt_hdr->first_part_lba));
+	if (full_read(dev_fd, part_array, part_array_len) != part_array_len) {
+		fdisk_fatal(unable_to_read);
+	}
+
+	if (gpt_crc32(part_array, part_array_len) != gpt_hdr->part_array_crc32) {
+		/* FIXME: read the backup table */
+		puts("\nwarning: GPT array CRC is invalid\n");
+	}
+
+	puts("Found valid GPT with protective MBR; using GPT\n");
+
+	current_label_type = LABEL_GPT;
+	return 1;
+}
+
+#endif /* GPT_LABEL */