libblkid: consolidate magic strings detection code

Signed-off-by: Karel Zak <kzak@redhat.com>

4 files changed, 46 insertions, 49 deletions

diff --git a/shlibs/blkid/src/blkidP.h b/shlibs/blkid/src/blkidP.h
index 41eba9102..6ac8910cc 100644
--- a/shlibs/blkid/src/blkidP.h
+++ b/shlibs/blkid/src/blkidP.h
@@ -386,6 +386,9 @@ extern int blkid_probe_get_dimension(blkid_probe pr,
 extern int blkid_probe_set_dimension(blkid_probe pr,
 	                blkid_loff_t off, blkid_loff_t size);
 
+extern int blkid_probe_get_idmag(blkid_probe pr, const struct blkid_idinfo *id,
+			blkid_loff_t *offset, const struct blkid_idmag **res);
+
 /* returns superblok according to 'struct blkid_idmag' */
 #define blkid_probe_get_sb(_pr, _mag, type) \
 			((type *) blkid_probe_get_buffer((_pr),\
diff --git a/shlibs/blkid/src/partitions/partitions.c b/shlibs/blkid/src/partitions/partitions.c
index d6abc203d..5b34d037e 100644
--- a/shlibs/blkid/src/partitions/partitions.c
+++ b/shlibs/blkid/src/partitions/partitions.c
@@ -515,35 +515,12 @@ int blkid_is_nested_dimension(blkid_partition par,
 static int idinfo_probe(blkid_probe pr, const struct blkid_idinfo *id)
 {
 	const struct blkid_idmag *mag;
-	int hasmag = 0;
 	int rc = 1;		/* = nothing detected */
 
 	if (pr->size <= 0 || (id->minsz && id->minsz > pr->size))
 		goto nothing;	/* the device is too small */
 
-	mag = id->magics ? &id->magics[0] : NULL;
-
-	/* try to detect by magic string */
-	while(mag && mag->magic) {
-		int idx;
-		unsigned char *buf;
-
-		idx = mag->kboff + (mag->sboff >> 10);
-		buf = blkid_probe_get_buffer(pr, idx << 10, 1024);
-
-		if (buf && !memcmp(mag->magic,
-				buf + (mag->sboff & 0x3ff), mag->len)) {
-			DBG(DEBUG_LOWPROBE, printf(
-				"%s: magic sboff=%u, kboff=%ld\n",
-				id->name, mag->sboff, mag->kboff));
-			hasmag = 1;
-			break;
-		}
-		mag++;
-	}
-
-	if (hasmag == 0 && id->magics && id->magics[0].magic)
-		/* magic string(s) defined, but not found */
+	if (blkid_probe_get_idmag(pr, id, NULL, &mag))
 		goto nothing;
 
 	/* final check by probing function */
diff --git a/shlibs/blkid/src/probe.c b/shlibs/blkid/src/probe.c
index 9353ecd2e..a748f2e24 100644
--- a/shlibs/blkid/src/probe.c
+++ b/shlibs/blkid/src/probe.c
@@ -714,6 +714,45 @@ int blkid_probe_set_dimension(blkid_probe pr,
 	return 0;
 }
 
+int blkid_probe_get_idmag(blkid_probe pr, const struct blkid_idinfo *id,
+			blkid_loff_t *offset, const struct blkid_idmag **res)
+{
+	const struct blkid_idmag *mag = NULL;
+	blkid_loff_t off = 0;
+
+	if (id)
+		mag = id->magics ? &id->magics[0] : NULL;
+	if (res)
+		*res = NULL;
+
+	/* try to detect by magic string */
+	while(mag && mag->magic) {
+		unsigned char *buf;
+
+		off = (mag->kboff + (mag->sboff >> 10)) << 10;
+		buf = blkid_probe_get_buffer(pr, off, 1024);
+
+		if (buf && !memcmp(mag->magic,
+				buf + (mag->sboff & 0x3ff), mag->len)) {
+			DBG(DEBUG_LOWPROBE, printf(
+				"\tmagic sboff=%u, kboff=%ld\n",
+				mag->sboff, mag->kboff));
+			if (offset)
+				*offset = off + (mag->sboff & 0x3ff);
+			if (res)
+				*res = mag;
+			return 0;
+		}
+		mag++;
+	}
+
+	if (id->magics && id->magics[0].magic)
+		/* magic string(s) defined, but not found */
+		return 1;
+
+	return 0;
+}
+
 static inline void blkid_probe_start(blkid_probe pr)
 {
 	if (pr) {
diff --git a/shlibs/blkid/src/superblocks/superblocks.c b/shlibs/blkid/src/superblocks/superblocks.c
index 95c10d6eb..268b2d9b7 100644
--- a/shlibs/blkid/src/superblocks/superblocks.c
+++ b/shlibs/blkid/src/superblocks/superblocks.c
@@ -322,11 +322,9 @@ static int superblocks_probe(blkid_probe pr, struct blkid_chain *chn)
 
 	for ( ; i < ARRAY_SIZE(idinfos); i++) {
 		const struct blkid_idinfo *id;
-		const struct blkid_idmag *mag;
+		const struct blkid_idmag *mag = NULL;
 		blkid_loff_t off = 0;
 
-		int hasmag = 0;
-
 		chn->idx = i;
 
 		if (chn->fltr && blkid_bmp_get_item(chn->fltr, i))
@@ -351,27 +349,7 @@ static int superblocks_probe(blkid_probe pr, struct blkid_chain *chn)
 
 		DBG(DEBUG_LOWPROBE, printf("[%d] %s:\n", i, id->name));
 
-		/* try to detect by magic string */
-		while(mag && mag->magic) {
-			unsigned char *buf;
-
-			off = (mag->kboff + (mag->sboff >> 10)) << 10;
-			buf = blkid_probe_get_buffer(pr, off, 1024);
-
-			if (buf && !memcmp(mag->magic,
-					buf + (mag->sboff & 0x3ff), mag->len)) {
-				DBG(DEBUG_LOWPROBE, printf(
-					"\tmagic sboff=%u, kboff=%ld\n",
-					mag->sboff, mag->kboff));
-				hasmag = 1;
-				off += mag->sboff & 0x3ff;
-				break;
-			}
-			mag++;
-		}
-
-		if (hasmag == 0 && id->magics && id->magics[0].magic)
-			/* magic string(s) defined, but not found */
+		if (blkid_probe_get_idmag(pr, id, &off, &mag))
 			continue;
 
 		/* final check by probing function */
@@ -391,7 +369,7 @@ static int superblocks_probe(blkid_probe pr, struct blkid_chain *chn)
 
 		blkid_probe_set_usage(pr, id->usage);
 
-		if (hasmag)
+		if (mag)
 			blkid_probe_set_magic(pr, off, mag->len,
 					(unsigned char *) mag->magic);