Imported Upstream version 2.22upstream/2.22upstream

1 files changed, 216 insertions, 0 deletions

diff --git a/fdisks/gpt.c b/fdisks/gpt.c
new file mode 100644
index 0000000..bb6911a
--- /dev/null
+++ b/fdisks/gpt.c
@@ -0,0 +1,216 @@
+/*
+ *
+ * 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 2 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, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
+ *
+ *
+ * GPT (GUID Partition Table) signature detection. Based on libparted and
+ * util-linux/partx.
+ *
+ * Warning: this code doesn't do all GPT checks (CRC32, Protective MBR, ..).
+ *          It's really GPT signature detection only.
+ *
+ * Copyright (C) 2007 Karel Zak <kzak@redhat.com>
+ *
+ */
+
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include <inttypes.h>
+#include <sys/stat.h>
+#include <sys/utsname.h>
+#include <sys/types.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <errno.h>
+
+#include "gpt.h"
+#include "blkdev.h"
+#include "bitops.h"
+#include "closestream.h"
+
+#define GPT_HEADER_SIGNATURE 0x5452415020494645LL
+#define GPT_PRIMARY_PARTITION_TABLE_LBA 1
+
+typedef struct {
+        uint32_t time_low;
+        uint16_t time_mid;
+        uint16_t time_hi_and_version;
+        uint8_t  clock_seq_hi_and_reserved;
+        uint8_t  clock_seq_low;
+        uint8_t  node[6];
+} /* __attribute__ ((packed)) */ efi_guid_t;
+/* commented out "__attribute__ ((packed))" to work around gcc bug (fixed
+ * in gcc3.1): __attribute__ ((packed)) breaks addressing on initialized
+ * data.  It turns out we don't need it in this case, so it doesn't break
+ * anything :)
+ */
+
+typedef struct _GuidPartitionTableHeader_t {
+	uint64_t Signature;
+	uint32_t Revision;
+	uint32_t HeaderSize;
+	uint32_t HeaderCRC32;
+	uint32_t Reserved1;
+	uint64_t MyLBA;
+	uint64_t AlternateLBA;
+	uint64_t FirstUsableLBA;
+	uint64_t LastUsableLBA;
+	efi_guid_t DiskGUID;
+	uint64_t PartitionEntryLBA;
+	uint32_t NumberOfPartitionEntries;
+	uint32_t SizeOfPartitionEntry;
+	uint32_t PartitionEntryArrayCRC32;
+	uint8_t Reserved2[512 - 92];
+} __attribute__ ((packed)) GuidPartitionTableHeader_t;
+
+static int
+_get_sector_size (int fd)
+{
+	int sector_size;
+
+	if (blkdev_get_sector_size(fd, &sector_size) == -1)
+		return DEFAULT_SECTOR_SIZE;
+	return sector_size;
+}
+
+static uint64_t
+_get_num_sectors(int fd)
+{
+	unsigned long long bytes=0;
+
+	if (blkdev_get_size(fd, &bytes) == -1)
+		return 0;
+	return bytes / _get_sector_size(fd);
+}
+
+static uint64_t
+last_lba(int fd)
+{
+	int rc;
+	uint64_t sectors = 0;
+	struct stat s;
+
+	memset(&s, 0, sizeof (s));
+	rc = fstat(fd, &s);
+	if (rc == -1)
+	{
+		fprintf(stderr, "last_lba() could not stat: %m\n");
+		return 0;
+	}
+	if (S_ISBLK(s.st_mode))
+		sectors = _get_num_sectors(fd);
+	else if (S_ISREG(s.st_mode))
+		sectors = s.st_size >> _get_sector_size(fd);
+	else
+	{
+		fprintf(stderr,
+			"last_lba(): I don't know how to handle files with mode %o\n",
+			s.st_mode);
+		sectors = 1;
+	}
+	return sectors - 1;
+}
+
+static ssize_t
+read_lba(int fd, uint64_t lba, void *buffer, size_t bytes)
+{
+	int sector_size = _get_sector_size(fd);
+	off_t offset = lba * sector_size;
+
+	lseek(fd, offset, SEEK_SET);
+	return read(fd, buffer, bytes);
+}
+
+static GuidPartitionTableHeader_t *
+alloc_read_gpt_header(int fd, uint64_t lba)
+{
+	GuidPartitionTableHeader_t *gpt =
+		(GuidPartitionTableHeader_t *) malloc(sizeof (GuidPartitionTableHeader_t));
+	if (!gpt)
+		return NULL;
+	memset(gpt, 0, sizeof (*gpt));
+	if (!read_lba(fd, lba, gpt, sizeof (GuidPartitionTableHeader_t)))
+	{
+		free(gpt);
+		return NULL;
+	}
+	return gpt;
+}
+
+static int
+gpt_check_signature(int fd, uint64_t lba)
+{
+	GuidPartitionTableHeader_t *gpt;
+	int res=0;
+
+	if ((gpt = alloc_read_gpt_header(fd, lba)))
+	{
+		if (gpt->Signature == cpu_to_le64(GPT_HEADER_SIGNATURE))
+			res = 1;
+		free(gpt);
+	}
+	return res;
+}
+
+/* returns:
+ *	0 not found GPT
+ *	1 for valid primary GPT header
+ *	2 for valid alternative GPT header
+ */
+int
+gpt_probe_signature_fd(int fd)
+{
+	int res = 0;
+
+	/* check primary GPT header */
+	if (gpt_check_signature(fd, GPT_PRIMARY_PARTITION_TABLE_LBA))
+		res = 1;
+	else
+	{
+		/* check alternative GPT header */
+		uint64_t lastlba = last_lba(fd);
+		if (gpt_check_signature(fd, lastlba))
+			res = 2;
+	}
+	return res;
+}
+
+int
+gpt_probe_signature_devname(char *devname)
+{
+	int res, fd;
+	if ((fd = open(devname, O_RDONLY)) < 0)
+		return 0;
+	res = gpt_probe_signature_fd(fd);
+	close(fd);
+	return res;
+}
+
+#ifdef GPT_TEST_MAIN
+int
+main(int argc, char **argv)
+{
+	atexit(close_stdout);
+	if (argc!=2)
+	{
+		fprintf(stderr, "usage: %s <dev>\n", argv[0]);
+		exit(EXIT_FAILURE);
+	}
+	if (gpt_probe_signature_devname(argv[1]))
+		printf("GPT (GUID Partition Table) detected on %s\n", argv[1]);
+	exit(EXIT_SUCCESS);
+}
+#endif