Imported from util-linux-2.10m tarball.

1 files changed, 106 insertions, 0 deletions

diff --git a/partx/dos.c b/partx/dos.c
new file mode 100644
index 000000000..b32801e0b
--- /dev/null
+++ b/partx/dos.c
@@ -0,0 +1,106 @@
+#include <stdio.h>
+#include "partx.h"
+
+struct partition {
+        unsigned char boot_ind;         /* 0x80 - active */
+        unsigned char bh, bs, bc;
+        unsigned char sys_type;
+        unsigned char eh, es, ec;
+        unsigned int start_sect;
+        unsigned int nr_sects;
+};
+
+static int
+is_extended(int type) {
+	return (type == 5 || type == 0xf || type == 0x85);
+}
+
+static int
+read_extended_partition(int fd, struct partition *ep,
+			struct slice *sp, int ns) {
+	struct partition *p;
+	unsigned long start, here, next;
+	unsigned char *bp;
+	int loopct = 0;
+	int moretodo = 1;
+	int i, n=0;
+
+	here = start = ep->start_sect;
+
+	while (moretodo) {
+		moretodo = 0;
+		if (++loopct > 100)
+			return n;
+
+		bp = getblock(fd, here);
+		if (bp == NULL)
+			return n;
+
+		if (bp[510] != 0x55 || bp[511] != 0xaa)
+			return n;
+
+		p = (struct partition *) (bp + 0x1be);
+
+		for (i=0; i<2; i++, p++) {
+			if (p->nr_sects == 0 || is_extended(p->sys_type))
+				continue;
+			if (n < ns) {
+				sp[n].start = here + p->start_sect;
+				sp[n].size = p->nr_sects;
+				n++;
+			} else {
+				fprintf(stderr,
+				    "dos_extd_partition: too many slices\n");
+				return n;
+			}
+			loopct = 0;
+		}
+
+		p -= 2;
+		for (i=0; i<2; i++, p++) {
+			if(p->nr_sects != 0 && is_extended(p->sys_type)) {
+				here = start + p->start_sect;
+				moretodo = 1;
+				break;
+			}
+		}
+	}
+	return n;
+}
+
+int
+read_dos_pt(int fd, struct slice all, struct slice *sp, int ns) {
+	struct partition *p;
+	unsigned long offset = all.start;
+	int i, n=0;
+	unsigned char *bp;
+
+	bp = getblock(fd, offset);
+	if (bp == NULL)
+		return -1;
+
+	if (bp[510] != 0x55 || bp[511] != 0xaa)
+		return -1;
+
+	p = (struct partition *) (bp + 0x1be);
+	for (i=0; i<4; i++) {
+		/* always add, even if zero length */
+		if (n < ns) {
+			sp[n].start = p->start_sect;
+			sp[n].size = p->nr_sects;
+			n++;
+		} else {
+			fprintf(stderr,
+				"dos_partition: too many slices\n");
+			break;
+		}
+		p++;
+	}
+	p = (struct partition *) (bp + 0x1be);
+	for (i=0; i<4; i++) {
+		if (is_extended(p->sys_type))
+			n += read_extended_partition(fd, p, sp+n, ns-n);
+		p++;
+	}
+	return n;
+}