lib: [sysfs.c] make sysfs_read_* function more robust

The functions does not modify result if the requested sysfs attribute
does not exist.

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

3 files changed, 17 insertions, 7 deletions

diff --git a/shlibs/blkid/src/devname.c b/shlibs/blkid/src/devname.c
index 81eac9aa3..2ed85cdbd 100644
--- a/shlibs/blkid/src/devname.c
+++ b/shlibs/blkid/src/devname.c
@@ -555,7 +555,7 @@ static int probe_all_removable(blkid_cache cache)
 
 	while((d = readdir(dir))) {
 		struct sysfs_cxt sysfs;
-		int removable;
+		int removable = 0;
 		dev_t devno;
 
 #ifdef _DIRENT_HAVE_D_TYPE
@@ -572,7 +572,7 @@ static int probe_all_removable(blkid_cache cache)
 			continue;
 
 		sysfs_init(&sysfs, devno, NULL);
-		removable = sysfs_read_int(&sysfs, "removable");
+		sysfs_read_int(&sysfs, "removable", &removable);
 		sysfs_deinit(&sysfs);
 
 		if (removable)
diff --git a/shlibs/blkid/src/partitions/partitions.c b/shlibs/blkid/src/partitions/partitions.c
index 2ac297a1c..060461d27 100644
--- a/shlibs/blkid/src/partitions/partitions.c
+++ b/shlibs/blkid/src/partitions/partitions.c
@@ -892,16 +892,20 @@ blkid_partition blkid_partlist_devno_to_partition(blkid_partlist ls, dev_t devno
 {
 	struct sysfs_cxt sysfs;
 	uint64_t start, size;
-	int i;
+	int i, rc;
 
 	if (sysfs_init(&sysfs, devno, NULL))
 		return NULL;
 
-	start = sysfs_read_u64(&sysfs, "start");
-	size = sysfs_read_u64(&sysfs, "size");
+	rc = sysfs_read_u64(&sysfs, "start", &start);
+	if (!rc)
+		rc = sysfs_read_u64(&sysfs, "size", &size);
 
 	sysfs_deinit(&sysfs);
 
+	if (rc)
+		return NULL;
+
 	for (i = 0; i < ls->nparts; i++) {
 		blkid_partition par = &ls->parts[i];
 
diff --git a/shlibs/blkid/src/topology/sysfs.c b/shlibs/blkid/src/topology/sysfs.c
index d5169d02a..fccd58f4d 100644
--- a/shlibs/blkid/src/topology/sysfs.c
+++ b/shlibs/blkid/src/topology/sysfs.c
@@ -78,11 +78,17 @@ static int probe_sysfs_tp(blkid_probe pr, const struct blkid_idmag *mag)
 		}
 
 		if (val->set_ulong) {
-			uint64_t data = sysfs_read_u64(&sysfs, val->attr);
+			uint64_t data;
+
+			if (sysfs_read_u64(&sysfs, val->attr, &data) != 0)
+				continue;
 			rc = val->set_ulong(pr, (unsigned long) data);
 
 		} else if (val->set_int) {
-			int64_t data = sysfs_read_s64(&sysfs, val->attr);
+			int64_t data;
+
+			if (sysfs_read_s64(&sysfs, val->attr, &data) != 0)
+				continue;
 			rc = val->set_int(pr, (int) data);
 		}