lofi_file_offset.diff

diff --git a/usr/src/cmd/lofiadm/main.c b/usr/src/cmd/lofiadm/main.c
index deadd4c..7229454 100644
--- a/usr/src/cmd/lofiadm/main.c
+++ b/usr/src/cmd/lofiadm/main.c
@@ -65,7 +65,7 @@
 static const char USAGE[] =
 	"Usage: %s -a file [ device ] "
 	" [-c aes-128-cbc|aes-192-cbc|aes-256-cbc|des3-cbc|blowfish-cbc]"
-	" [-e] [-k keyfile] [-T [token]:[manuf]:[serial]:key]\n"
+	" [-e] [-k keyfile] [-T [token]:[manuf]:[serial]:key] [-O offset]\n"
 	"       %s -d file | device\n"
 	"       %s -C [gzip|gzip-6|gzip-9|lzma] [-s segment_size] file\n"
 	"       %s -U file\n"
@@ -363,10 +363,12 @@ lofi_map_file(int lfd, struct lofi_ioctl li, const char *filename)
  */
 static void
 add_mapping(int lfd, const char *devicename, const char *filename,
-    mech_alias_t *cipher, const char *rkey, size_t rksz)
+    mech_alias_t *cipher, const char *rkey, size_t rksz, u_offset_t file_offset)
 {
 	struct lofi_ioctl li;
 
+	li.li_file_offset = file_offset;
+
 	li.li_crypto_enabled = B_FALSE;
 	if (cipher != NULL) {
 		/* set up encryption for mapped file */
@@ -1770,6 +1772,43 @@ convert_to_num(const char *str)
 	return (segsize);
 }
 
+static uint64_t
+convert_to_offset(const char *str)
+{
+	int len;
+	u_offset_t r, mult = 1;
+
+
+	len = strlen(str);
+	if (len && isalpha(str[len - 1])) {
+		switch (str[len - 1]) {
+		case 'k':
+		case 'K':
+			mult = KILOBYTE;
+			break;
+		case 'b':
+		case 'B':
+			mult = BLOCK_SIZE;
+			break;
+		case 'm':
+		case 'M':
+			mult = MEGABYTE;
+			break;
+		case 'g':
+		case 'G':
+			mult = GIGABYTE;
+			break;
+		default:
+			die(gettext("invalid offset %s\n"), str);
+		}
+	}
+
+	r = atoll(str);
+	r *= mult;
+
+	return (r);
+}
+
 int
 main(int argc, char *argv[])
 {
@@ -1782,6 +1821,7 @@ main(int argc, char *argv[])
 	int	minor;
 	int 	compress_index;
 	uint32_t segsize = SEGSIZE;
+	u_offset_t file_offset = 0;
 	static char *lofictl = "/dev/" LOFI_CTL_NAME;
 	boolean_t force = B_FALSE;
 	const char *pname;
@@ -1791,6 +1831,7 @@ main(int argc, char *argv[])
 	boolean_t ephflag = B_FALSE;
 	boolean_t compressflag = B_FALSE;
 	boolean_t uncompressflag = B_FALSE;
+	boolean_t file_offsetflag = B_FALSE;
 	/* the next two work together for -c, -k, -T, -e options only */
 	boolean_t need_crypto = B_FALSE;	/* if any -c, -k, -T, -e */
 	boolean_t cipher_only = B_TRUE;		/* if -c only */
@@ -1806,7 +1847,7 @@ main(int argc, char *argv[])
 	(void) setlocale(LC_ALL, "");
 	(void) textdomain(TEXT_DOMAIN);
 
-	while ((c = getopt(argc, argv, "a:c:Cd:efk:o:s:T:U")) != EOF) {
+	while ((c = getopt(argc, argv, "a:c:Cd:efk:o:s:O:T:U")) != EOF) {
 		switch (c) {
 		case 'a':
 			addflag = B_TRUE;
@@ -1881,6 +1922,10 @@ main(int argc, char *argv[])
 		case 'U':
 			uncompressflag = B_TRUE;
 			break;
+		case 'O':
+			file_offsetflag = B_TRUE;
+			file_offset = convert_to_offset(optarg);
+			break;
 		case '?':
 		default:
 			errflag = B_TRUE;
@@ -2007,7 +2052,7 @@ main(int argc, char *argv[])
 	 * Now to the real work.
 	 */
 	if (addflag)
-		add_mapping(lfd, devicename, filename, cipher, rkey, rksz);
+		add_mapping(lfd, devicename, filename, cipher, rkey, rksz, file_offset);
 	else if (compressflag)
 		lofi_compress(&lfd, filename, compress_index, segsize);
 	else if (uncompressflag)
diff --git a/usr/src/uts/common/io/lofi.c b/usr/src/uts/common/io/lofi.c
index 049a023..f2d0f18 100644
--- a/usr/src/uts/common/io/lofi.c
+++ b/usr/src/uts/common/io/lofi.c
@@ -1018,7 +1018,7 @@ lofi_strategy_task(void *arg)
 	}
 	bp_mapin(bp);
 	bufaddr = bp->b_un.b_addr;
-	offset = bp->b_lblkno * DEV_BSIZE;	/* offset within file */
+	offset = bp->b_lblkno * DEV_BSIZE + lsp->ls_file_offset;	/* offset within file */
 	if (lsp->ls_crypto_enabled) {
 		/* encrypted data really begins after crypto header */
 		offset += lsp->ls_crypto_offset;
@@ -1373,7 +1373,7 @@ lofi_strategy(struct buf *bp)
 		return (0);
 	}
 
-	offset = bp->b_lblkno * DEV_BSIZE;	/* offset within file */
+	offset = bp->b_lblkno * DEV_BSIZE + lsp->ls_file_offset;	/* offset within file */
 	if (lsp->ls_crypto_enabled) {
 		/* encrypted data really begins after crypto header */
 		offset += lsp->ls_crypto_offset;
@@ -1689,7 +1689,7 @@ file_to_lofi(char *filename, struct lofi_state **lspp)
 static void
 fake_disk_geometry(struct lofi_state *lsp)
 {
-	u_offset_t dsize = lsp->ls_vp_size - lsp->ls_crypto_offset;
+	u_offset_t dsize = lsp->ls_vp_size - lsp->ls_crypto_offset - lsp->ls_file_offset;
 
 	/* dk_geom - see dkio(7I) */
 	/*
@@ -2189,6 +2189,7 @@ lofi_map_file(dev_t dev, struct lofi_ioctl *ulip, int pickminor,
 	lsp->ls_uncomp_seg_sz = 0;
 	lsp->ls_comp_algorithm[0] = '\0';
 	lsp->ls_crypto_offset = 0;
+	lsp->ls_file_offset = klip->li_file_offset;
 
 	cv_init(&lsp->ls_vp_cv, NULL, CV_DRIVER, NULL);
 	mutex_init(&lsp->ls_comp_cache_lock, NULL, MUTEX_DRIVER, NULL);
diff --git a/usr/src/uts/common/sys/lofi.h b/usr/src/uts/common/sys/lofi.h
index d82cc03..dbad3c4 100644
--- a/usr/src/uts/common/sys/lofi.h
+++ b/usr/src/uts/common/sys/lofi.h
@@ -141,6 +141,8 @@ struct lofi_ioctl {
 	crypto_mech_name_t	li_iv_cipher;	/* for iv derivation */
 	uint32_t	li_iv_len;		/* for iv derivation */
 	iv_method_t	li_iv_type;		/* for iv derivation */
+
+	u_offset_t	li_file_offset;
 };
 
 #define	LOFI_IOC_BASE		(('L' << 16) | ('F' << 8))
@@ -266,7 +268,7 @@ struct lofi_state {
 	iv_method_t		ls_iv_type;	/* for iv derivation */
 	kmutex_t		ls_crypto_lock;
 	crypto_ctx_template_t	ls_ctx_tmpl;
-
+	u_offset_t		ls_file_offset;
 };
 
 #endif	/* _KERNEL */