daemon: ldm: Don't return an error if /dev/mapper doesn't exist.

daemon/daemon.h

@@ -105,6 +105,8 @@ extern char *join_strings (const char *separator, char *const *argv);
 
 extern char **split_lines (char *str);
 
+extern char **empty_list (void);
+
 #define command(out,err,name,...) commandf((out),(err),0,(name),__VA_ARGS__)
 #define commandr(out,err,name,...) commandrf((out),(err),0,(name),__VA_ARGS__)
 #define commandv(out,err,argv) commandvf((out),(err),0,(argv))

daemon/guestfsd.c

@@ -1019,7 +1019,7 @@ split_lines (char *str)
   char *p, *pend;
 
   if (STREQ (str, ""))
-    goto empty_list;
+    return empty_list ();
 
   p = str;
   while (p) {
@@ -1040,13 +1040,23 @@ split_lines (char *str)
     p = pend;
   }
 
- empty_list:
   if (end_stringsbuf (&lines) == -1)
     return NULL;
 
   return lines.argv;
 }
 
+char **
+empty_list (void)
+{
+  DECLARE_STRINGSBUF (ret);
+
+  if (end_stringsbuf (&ret) == -1)
+    return NULL;
+
+  return ret.argv;
+}
+
 /* Skip leading and trailing whitespace, updating the original string
  * in-place.
  */

daemon/ldm.c

@@ -20,6 +20,9 @@
 
 #include <stdio.h>
 #include <stdlib.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/stat.h>
 #include <glob.h>
 
 #if HAVE_YAJL
@@ -91,6 +94,16 @@ get_devices (const char *pattern)
 char **
 do_list_ldm_volumes (void)
 {
+  struct stat buf;
+
+  /* If /dev/mapper doesn't exist at all, don't give an error. */
+  if (stat ("/dev/mapper", &buf) == -1) {
+    if (errno == ENOENT)
+      return empty_list ();
+    reply_with_perror ("/dev/mapper");
+    return NULL;
+  }
+
   return get_devices ("/dev/mapper/ldm_vol_*");
 }
 
@@ -98,6 +111,16 @@ do_list_ldm_volumes (void)
 char **
 do_list_ldm_partitions (void)
 {
+  struct stat buf;
+
+  /* If /dev/mapper doesn't exist at all, don't give an error. */
+  if (stat ("/dev/mapper", &buf) == -1) {
+    if (errno == ENOENT)
+      return empty_list ();
+    reply_with_perror ("/dev/mapper");
+    return NULL;
+  }
+
   return get_devices ("/dev/mapper/ldm_part_*");
 }