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authorKarel Zak <kzak@redhat.com>2009-10-26 13:33:03 +0100
committerKarel Zak <kzak@redhat.com>2009-10-26 13:33:03 +0100
commita992137b7b8720600c99917af87f0e4cddad8682 (patch)
tree58a399775862e76292e5673c75e4c89b8280bd42 /lib
parent4c8e837230bb96dc3c447706d9c3b11e4167ba13 (diff)
downloadutil-linux-old-a992137b7b8720600c99917af87f0e4cddad8682.tar.gz
mount: and libblkid: covert /dev/dm-N to /dev/mapper/<name>
* mount(8) uses private device-mapper names in mtab * libblkid returns private device-mapper names when evaluate udev /dev/disk-by symlinks. * on systems where DM is fully integrated with udev the /dev/mapper/<name> files are symlinks to /dev/dm-N. It means we need a special care to hide private device-mapper names. Signed-off-by: Karel Zak <kzak@redhat.com>
Diffstat (limited to 'lib')
-rw-r--r--lib/canonicalize.c48
1 files changed, 44 insertions, 4 deletions
diff --git a/lib/canonicalize.c b/lib/canonicalize.c
index b888fbb8..e54cf0c0 100644
--- a/lib/canonicalize.c
+++ b/lib/canonicalize.c
@@ -20,6 +20,9 @@
*
* TODO: use canonicalize_file_name() when exist in glibc
*/
+#include <stdio.h>
+#include <string.h>
+#include <ctype.h>
#include <unistd.h>
#include <string.h>
#include <errno.h>
@@ -136,17 +139,54 @@ myrealpath(const char *path, char *resolved_path, int maxreslth) {
return NULL;
}
+/*
+ * Converts private "dm-N" names to "/dev/mapper/<name>"
+ *
+ * Since 2.6.29 (patch 784aae735d9b0bba3f8b9faef4c8b30df3bf0128) kernel sysfs
+ * provides the real DM device names in /sys/block/<ptname>/dm/name
+ */
char *
-canonicalize_path(const char *path) {
+canonicalize_dm_name(const char *ptname)
+{
+ FILE *f;
+ size_t sz;
+ char path[256], name[256], *res = NULL;
+
+ snprintf(path, sizeof(path), "/sys/block/%s/dm/name", ptname);
+ if (!(f = fopen(path, "r")))
+ return NULL;
+
+ /* read "<name>\n" from sysfs */
+ if (fgets(name, sizeof(name), f) && (sz = strlen(name)) > 1) {
+ name[sz - 1] = '\0';
+ snprintf(path, sizeof(path), "/dev/mapper/%s", name);
+ res = strdup(path);
+ }
+ fclose(f);
+ return res;
+}
+
+char *
+canonicalize_path(const char *path)
+{
char canonical[PATH_MAX+2];
+ char *p;
if (path == NULL)
return NULL;
- if (myrealpath (path, canonical, PATH_MAX+1))
- return strdup(canonical);
+ if (!myrealpath(path, canonical, PATH_MAX+1))
+ return strdup(path);
+
+
+ p = strrchr(canonical, '/');
+ if (p && strncmp(p, "/dm-", 4) == 0 && isdigit(*(p + 4))) {
+ p = canonicalize_dm_name(p+1);
+ if (p)
+ return p;
+ }
- return strdup(path);
+ return strdup(canonical);
}