From: Karel Zak <kzak@redhat.com>
Date: Thu, 1 Oct 2009 22:49:07 +0000 (+0200)
Subject: libblkid: fix blkid_do_probe() to work properly with chains
X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=44ef90bcbdcb5de977b9ff0bd3dd9bb9b92b99fb;p=util-linux

libblkid: fix blkid_do_probe() to work properly with chains

The blkid_do_probe() always switched to the new chain -- that's bad, we
have to try all probing methods in the chain.

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

diff --git a/shlibs/blkid/src/probe.c b/shlibs/blkid/src/probe.c
index 054cc920..078669f4 100644
--- a/shlibs/blkid/src/probe.c
+++ b/shlibs/blkid/src/probe.c
@@ -319,8 +319,9 @@ void *blkid_probe_get_binary_data(blkid_probe pr, struct blkid_chain *chn)
  * blkid_reset_probe:
  * @pr: probe
  *
- * Cleanup probing result. This function does not touch probing filters
- * and keeps assigned device.
+ * Zeroize probing results and resets the current probing (this has impact to
+ * blkid_do_probe() only). This function does not touch probing filters and
+ * keeps assigned device.
  */
 void blkid_reset_probe(blkid_probe pr)
 {
@@ -332,6 +333,8 @@ void blkid_reset_probe(blkid_probe pr)
 	blkid_probe_reset_buffer(pr);
 	blkid_probe_reset_vals(pr);
 
+	pr->cur_chain = NULL;
+
 	for (i = 0; i < BLKID_NCHAINS; i++)
 		pr->chains[i].idx = -1;
 }
@@ -537,7 +540,7 @@ unsigned char *blkid_probe_get_buffer(blkid_probe pr,
  * @size: size of probing area (zero means whole device/file)
  *
  * Assigns the device to probe control struct, resets internal buffers and
- * reads 512 bytes from device to the buffers.
+ * resets the current probing.
  *
  * Returns: -1 in case of failure, or 0 on success.
  */
@@ -634,7 +637,8 @@ int blkid_probe_set_dimension(blkid_probe pr,
  * Calls probing functions in all enabled chains. The superblocks chain is
  * enabled by default. The blkid_do_probe() stores result from only one
  * probing function. It's necessary to call this routine in a loop to get
- * resuluts from all probing functions in all chains.
+ * results from all probing functions in all chains. The probing is reseted
+ * by blkid_reset_probe() or by filter functions.
  *
  * This is string-based NAME=value interface only.
  *
@@ -675,25 +679,33 @@ int blkid_do_probe(blkid_probe pr)
 		return -1;
 
 	do {
-		struct blkid_chain *chn;
+		struct blkid_chain *chn = pr->cur_chain;
 
-		if (!pr->cur_chain)
-			pr->cur_chain = &pr->chains[0];
-		else {
-			int idx = pr->cur_chain->driver->id + 1;
+		if (!chn)
+			chn = pr->cur_chain = &pr->chains[0];
+
+		/* we go to the next chain only when the previous probing
+		 * result was nothing (rc == 1) and when the current chain is
+		 * disabled or we are at end of the current chain (chain->idx +
+		 * 1 == sizeof chain)
+		 */
+		else if (rc == 1 && (chn->enabled == FALSE ||
+				     chn->idx + 1 == chn->driver->nidinfos)) {
+
+			int idx = chn->driver->id + 1;
 
 			if (idx < BLKID_NCHAINS)
-				pr->cur_chain = &pr->chains[idx];
+				chn = pr->cur_chain = &pr->chains[idx];
 			else
 				return 1;	/* all chains already probed */
 		}
 
-		chn = pr->cur_chain;
 		chn->binary = FALSE;		/* for sure... */
 
-		DBG(DEBUG_LOWPROBE, printf("chain probe %s %s\n",
+		DBG(DEBUG_LOWPROBE, printf("chain probe %s %s (idx=%d)\n",
 				chn->driver->name,
-				chn->enabled? "ENABLED" : "DISABLED"));
+				chn->enabled? "ENABLED" : "DISABLED",
+				chn->idx));
 
 		if (!chn->enabled)
 			continue;
diff --git a/shlibs/blkid/src/superblocks/superblocks.c b/shlibs/blkid/src/superblocks/superblocks.c
index f3287368..8cd50c95 100644
--- a/shlibs/blkid/src/superblocks/superblocks.c
+++ b/shlibs/blkid/src/superblocks/superblocks.c
@@ -297,8 +297,6 @@ static int superblocks_probe(blkid_probe pr, struct blkid_chain *chn)
 
 	if (!pr || chn->idx < -1)
 		return -1;
-	if (chn->idx < -1)
-		return -1;
 	blkid_probe_chain_reset_vals(pr, chn);
 
 	DBG(DEBUG_LOWPROBE,
diff --git a/shlibs/blkid/src/topology/topology.c b/shlibs/blkid/src/topology/topology.c
index 80499005..072261f3 100644
--- a/shlibs/blkid/src/topology/topology.c
+++ b/shlibs/blkid/src/topology/topology.c
@@ -133,8 +133,6 @@ static int topology_probe(blkid_probe pr, struct blkid_chain *chn)
 
 	if (!pr || chn->idx < -1)
 		return -1;
-	if (chn->idx < -1)
-		return -1;
 
 	if (chn->binary) {
 		DBG(DEBUG_LOWPROBE, printf("initialize topology binary data\n"));