X-Git-Url: http://git.annexia.org/?p=libguestfs.git;a=blobdiff_plain;f=daemon%2Flvm.c;h=216c9c44ab5d6bc7938947cf5e85dad9e1c7b6fc;hp=70c3c9047a97c9400f162ef27987824d22f42d39;hb=8022d46e5e2d9c3ab664ace6c9f185976e34dc20;hpb=9be89728f2a0ff17d54a0dba981015fa6405eb50

diff --git a/daemon/lvm.c b/daemon/lvm.c
index 70c3c90..216c9c4 100644
--- a/daemon/lvm.c
+++ b/daemon/lvm.c
@@ -23,6 +23,7 @@
 #include <inttypes.h>
 #include <string.h>
 #include <unistd.h>
+#include <sys/stat.h>
 
 #include "daemon.h"
 #include "c-ctype.h"
@@ -662,3 +663,89 @@ do_vgscan (void)
   free (err);
   return 0;
 }
+
+/* Convert a non-canonical LV path like /dev/mapper/vg-lv or /dev/dm-0
+ * to a canonical one.
+ *
+ * This is harder than it should be.  A LV device like /dev/VG/LV is
+ * really a symlink to a device-mapper device like /dev/dm-0.  However
+ * at the device-mapper (kernel) level, nothing is really known about
+ * LVM (a userspace concept).  Therefore we use a convoluted method to
+ * determine this, by listing out known LVs and checking whether the
+ * rdev (major/minor) of the device we are passed matches any of them.
+ *
+ * Note use of 'stat' instead of 'lstat' so that symlinks are fully
+ * resolved.
+ *
+ * Returns:
+ *   1  =  conversion was successful, path is an LV
+ *         '*ret' is set to the updated path if 'ret' is non-NULL.
+ *   0  =  path is not an LV
+ *  -1  =  error, reply_with_* has been called
+ *
+ */
+int
+lv_canonical (const char *device, char **ret)
+{
+  struct stat stat1, stat2;
+
+  int r = stat (device, &stat1);
+  if (r == -1) {
+    reply_with_perror ("stat: %s", device);
+    return -1;
+  }
+
+  char **lvs = do_lvs ();
+  if (lvs == NULL)
+    return -1;
+
+  size_t i;
+  for (i = 0; lvs[i] != NULL; ++i) {
+    r = stat (lvs[i], &stat2);
+    if (r == -1) {
+      reply_with_perror ("stat: %s", lvs[i]);
+      free_strings (lvs);
+      return -1;
+    }
+    if (stat1.st_rdev == stat2.st_rdev) { /* found it */
+      if (ret) {
+        *ret = strdup (lvs[i]);
+        if (*ret == NULL) {
+          reply_with_perror ("strdup");
+          free_strings (lvs);
+          return -1;
+        }
+      }
+      free_strings (lvs);
+      return 1;
+    }
+  }
+
+  /* not found */
+  free_strings (lvs);
+  return 0;
+}
+
+/* Test if a device is a logical volume (RHBZ#619793). */
+int
+do_is_lv (const char *device)
+{
+  return lv_canonical (device, NULL);
+}
+
+/* Return canonical name of LV to caller (RHBZ#638899). */
+char *
+do_lvm_canonical_lv_name (const char *device)
+{
+  char *canonical;
+  int r = lv_canonical (device, &canonical);
+  if (r == -1)
+    return NULL;
+
+  if (r == 0) {
+    reply_with_error ("%s: not a logical volume", device);
+    return NULL;
+  }
+
+  return canonical;             /* caller frees */
+}