libblkid: support alignment_offset=-1

Unfortunately, Linux kernel uses "signed int" for alignment_offset and
the offset could be -1 for devices with undefined alignment (if no
compatible sizes and alignments exist for stacked devices).

There is no way how libblkid caller can respond to the value -1, so
we are going to hide this corner case...

TODO: maybe we can export an extra boolean value 'misaligned' rather
      then complete hide this problem. We will see...

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

7 files changed, 89 insertions, 60 deletions

diff --git a/shlibs/blkid/src/blkidP.h b/shlibs/blkid/src/blkidP.h
index c9b2bcd18..1de6dd064 100644
--- a/shlibs/blkid/src/blkidP.h
+++ b/shlibs/blkid/src/blkidP.h
@@ -333,8 +333,10 @@ struct dir_list {
 extern void blkid__scan_dir(char *, dev_t, struct dir_list **, char **);
 extern int blkid_driver_has_major(const char *drvname, int major);
 extern int blkid_devno_has_attribute(dev_t devno, const char *attribute);
-extern int blkid_devno_get_attribute(dev_t devno, const char *attribute,
+extern int blkid_devno_get_u64_attribute(dev_t devno, const char *attribute,
 							uint64_t *result);
+extern int blkid_devno_get_s64_attribute(dev_t devno, const char *attribute,
+							int64_t *result);
 
 /* lseek.c */
 extern blkid_loff_t blkid_llseek(int fd, blkid_loff_t offset, int whence);
diff --git a/shlibs/blkid/src/devno.c b/shlibs/blkid/src/devno.c
index 1b64ec1e1..a667becf5 100644
--- a/shlibs/blkid/src/devno.c
+++ b/shlibs/blkid/src/devno.c
@@ -478,7 +478,7 @@ int blkid_devno_has_attribute(dev_t devno, const char *attribute)
 	return 0;
 }
 
-int blkid_devno_get_attribute(dev_t devno, const char *attribute, uint64_t *result)
+int blkid_devno_get_u64_attribute(dev_t devno, const char *attribute, uint64_t *result)
 {
 	FILE *f;
 	char path[PATH_MAX];
@@ -496,6 +496,24 @@ int blkid_devno_get_attribute(dev_t devno, const char *attribute, uint64_t *resu
 	return rc == 1 ? 0 : -1;
 }
 
+int blkid_devno_get_s64_attribute(dev_t devno, const char *attribute, int64_t *result)
+{
+	FILE *f;
+	char path[PATH_MAX];
+	int rc = 0;
+
+	if (!mk_devno_attribute_path(path, sizeof(path), devno, attribute))
+		return -1;
+
+	f = fopen(path, "r");
+	if (f) {
+		rc = fscanf(f, "%" SCNd64, result);
+		fclose(f);
+	}
+
+	return rc == 1 ? 0 : -1;
+}
+
 #ifdef TEST_PROGRAM
 int main(int argc, char** argv)
 {
diff --git a/shlibs/blkid/src/partitions/partitions.c b/shlibs/blkid/src/partitions/partitions.c
index 9c3296e90..0f342fc87 100644
--- a/shlibs/blkid/src/partitions/partitions.c
+++ b/shlibs/blkid/src/partitions/partitions.c
@@ -828,9 +828,9 @@ blkid_partition blkid_partlist_devno_to_partition(blkid_partlist ls, dev_t devno
 	uint64_t start, size;
 	int i;
 
-	if (blkid_devno_get_attribute(devno, "start", &start))
+	if (blkid_devno_get_u64_attribute(devno, "start", &start))
 		return NULL;
-	if (blkid_devno_get_attribute(devno, "size", &size))
+	if (blkid_devno_get_u64_attribute(devno, "size", &size))
 		return NULL;
 
 	for (i = 0; i < ls->nparts; i++) {
diff --git a/shlibs/blkid/src/topology/ioctl.c b/shlibs/blkid/src/topology/ioctl.c
index 709b2f458..e85ecdf95 100644
--- a/shlibs/blkid/src/topology/ioctl.c
+++ b/shlibs/blkid/src/topology/ioctl.c
@@ -26,11 +26,12 @@ static struct topology_val {
 
 	long  ioc;
 
-	/* function to set probing resut */
-	int (*set_result)(blkid_probe, unsigned long);
+	/* functions to set probing resut */
+	int (*set_ulong)(blkid_probe, unsigned long);
+	int (*set_int)(blkid_probe, int);
 
 } topology_vals[] = {
-	{ BLKALIGNOFF, blkid_topology_set_alignment_offset },
+	{ BLKALIGNOFF, NULL, blkid_topology_set_alignment_offset },
 	{ BLKIOMIN, blkid_topology_set_minimum_io_size },
 	{ BLKIOOPT, blkid_topology_set_optimal_io_size },
 	{ BLKPBSZGET, blkid_topology_set_physical_sector_size }
@@ -44,12 +45,16 @@ static int probe_ioctl_tp(blkid_probe pr, const struct blkid_idmag *mag)
 
 	for (i = 0; i < ARRAY_SIZE(topology_vals); i++) {
 		struct topology_val *val = &topology_vals[i];
+		int rc = 1;
 		unsigned int data;
-		int rc;
 
 		if (ioctl(pr->fd, val->ioc, &data) == -1)
 			goto nothing;
-		rc = val->set_result(pr, (unsigned long) data);
+
+		if (val->set_int)
+			rc = val->set_int(pr, (int) data);
+		else
+			rc = val->set_ulong(pr, (unsigned long) data);
 		if (rc)
 			goto err;
 		count++;
diff --git a/shlibs/blkid/src/topology/sysfs.c b/shlibs/blkid/src/topology/sysfs.c
index ce870f226..25e2b0aa0 100644
--- a/shlibs/blkid/src/topology/sysfs.c
+++ b/shlibs/blkid/src/topology/sysfs.c
@@ -19,51 +19,20 @@
 
 #include "topology.h"
 
-static unsigned long dev_topology_attribute(const char *attribute,
-				dev_t dev, dev_t *primary)
-{
-	uint64_t result;
-
-	/*
-	 * check if the desired sysfs attribute exists
-	 * - if not: either the kernel doesn't have topology support or the
-	 *   device could be a partition
-	 */
-	if (!blkid_devno_has_attribute(dev, attribute)) {
-		if (!*primary &&
-		    blkid_devno_to_wholedisk(dev, NULL, 0, primary))
-			goto err;
-
-		/* get attribute from partition's primary device */
-		dev = *primary;
-	}
-
-	if (blkid_devno_get_attribute(dev, attribute, &result))
-		goto err;
-
-	DBG(DEBUG_LOWPROBE,
-		printf("topology: attribute %s = %" PRIu64 "\n", attribute, result));
-
-	return result;
-err:
-	DBG(DEBUG_LOWPROBE,
-		printf("topology: failed to read %s attribute\n", attribute));
-	return 0;
-}
-
 /*
  * Sysfs topology values (since 2.6.31, May 2009).
  */
 static struct topology_val {
 
-	/* /sys/dev/block/<maj>:<min>/NAME */
-	const char *sysfs_name;
+	/* /sys/dev/block/<maj>:<min>/<ATTR> */
+	const char *attr;
 
-	/* function to set probing resut */
-	int (*set_result)(blkid_probe, unsigned long);
+	/* functions to set probing resut */
+	int (*set_ulong)(blkid_probe, unsigned long);
+	int (*set_int)(blkid_probe, int);
 
 } topology_vals[] = {
-	{ "alignment_offset", blkid_topology_set_alignment_offset },
+	{ "alignment_offset", NULL, blkid_topology_set_alignment_offset },
 	{ "queue/minimum_io_size", blkid_topology_set_minimum_io_size },
 	{ "queue/optimal_io_size", blkid_topology_set_optimal_io_size },
 	{ "queue/physical_block_size", blkid_topology_set_physical_sector_size },
@@ -72,7 +41,7 @@ static struct topology_val {
 static int probe_sysfs_tp(blkid_probe pr, const struct blkid_idmag *mag)
 {
 	dev_t dev, pri_dev = 0;
-	int i, rc = 0, count = 0;
+	int i, count = 0;
 
 	dev = blkid_probe_get_devno(pr);
 	if (!dev)
@@ -80,17 +49,38 @@ static int probe_sysfs_tp(blkid_probe pr, const struct blkid_idmag *mag)
 
 	for (i = 0; i < ARRAY_SIZE(topology_vals); i++) {
 		struct topology_val *val = &topology_vals[i];
-		unsigned long data;
-
-		/*
-		 * Don't bother reporting any of the topology information
-		 * if it's zero.
-		 */
-		data = dev_topology_attribute(val->sysfs_name, dev, &pri_dev);
-		if (!data)
-			continue;
+		dev_t attr_dev = dev;
+		int rc = 1;
+
+		if (!blkid_devno_has_attribute(dev, val->attr)) {
+			/* get attribute from partition's primary device */
+			if (!pri_dev &&
+			    blkid_devno_to_wholedisk(dev, NULL, 0, &pri_dev))
+				continue;
+			attr_dev = pri_dev;
+		}
+
+		if (val->set_ulong) {
+			uint64_t data = 0;
+
+			if (blkid_devno_get_u64_attribute(attr_dev,
+							val->attr, &data))
+				continue;
+			if (!data)
+				continue;
+			rc = val->set_ulong(pr, (unsigned long) data);
+
+		} else if (val->set_int) {
+			int64_t data = 0;
+
+			if (blkid_devno_get_s64_attribute(attr_dev,
+							val->attr, &data))
+				continue;
+			if (!data)
+				continue;
+			rc = val->set_int(pr, (int) data);
+		}
 
-		rc = val->set_result(pr, data);
 		if (rc)
 			goto err;
 		count++;
diff --git a/shlibs/blkid/src/topology/topology.c b/shlibs/blkid/src/topology/topology.c
index db97c5fb2..fa49fd092 100644
--- a/shlibs/blkid/src/topology/topology.c
+++ b/shlibs/blkid/src/topology/topology.c
@@ -242,12 +242,26 @@ static int topology_is_complete(blkid_probe pr)
 	return __blkid_probe_lookup_value(pr, "MINIMUM_IO_SIZE") ? TRUE : FALSE;
 }
 
-int blkid_topology_set_alignment_offset(blkid_probe pr, unsigned long val)
+int blkid_topology_set_alignment_offset(blkid_probe pr, int val)
 {
+	unsigned long xval;
+
+	/* Welcome to Hell. The kernel is able to returns -1 as an
+	 * alignment_offset if no compatible sizes and alignments
+	 * exist for stacked devices.
+	 *
+	 * There is no way how libblkid caller can respond to the value -1, so
+	 * we will hide this corner case...
+	 *
+	 * (TODO: maybe we can export an extra boolean value 'misaligned' rather
+	 *  then complete hide this problem.)
+	 */
+	xval = val < 0 ? 0 : val;
+
 	return topology_set_value(pr,
 			"ALIGNMENT_OFFSET",
 			offsetof(struct blkid_struct_topology, alignment_offset),
-			val);
+			xval);
 }
 
 int blkid_topology_set_minimum_io_size(blkid_probe pr, unsigned long val)
diff --git a/shlibs/blkid/src/topology/topology.h b/shlibs/blkid/src/topology/topology.h
index d4879204d..b7429d904 100644
--- a/shlibs/blkid/src/topology/topology.h
+++ b/shlibs/blkid/src/topology/topology.h
@@ -3,7 +3,7 @@
 
 #include "blkidP.h"
 
-extern int blkid_topology_set_alignment_offset(blkid_probe pr, unsigned long val);
+extern int blkid_topology_set_alignment_offset(blkid_probe pr, int val);
 extern int blkid_topology_set_minimum_io_size(blkid_probe pr, unsigned long val);
 extern int blkid_topology_set_optimal_io_size(blkid_probe pr, unsigned long val);
 extern int blkid_topology_set_physical_sector_size(blkid_probe pr, unsigned long val);