[PATCH] use vgs --nameprefixes to protect against whitespace changes

[Andrey Borzenkov]

Do not assume single blank at the end of PV name. At least
lvm2-2.02.98-24.3 (openSUSE 13.1 M3) puts exra blank at the end.

linux-chxo:~ # grub2-probe -t abstraction /lib
mdadm: cannot open /dev/md1  : No such file or directory
grub2-probe: error: cannot open `/dev/md1  ': No such file or directory.
linux-chxo:~ # : Update grub with patch
linux-chxo:~ # grub2-probe -t abstraction /lib
diskfilter mdraid1x lvm 
linux-chxo:~ # vgs --options pv_name --noheadings | xxd
0000000: 2020 2f64 6576 2f6d 6431 2020 0a           /dev/md1  .
linux-chxo:~ # rpm -q lvm2
lvm2-2.02.98-24.3.i586

This patch changes it to use --nameprefixes which returns each PV name as
  LVM2_PV_NAME='xxx'

Signed-off-by: Andrey Borzenkov <address@hidden>

---
 util/getroot.c | 20 +++++++++++++++-----
 1 file changed, 15 insertions(+), 5 deletions(-)

diff --git a/util/getroot.c b/util/getroot.c
index 2ad8a55..479ab78 100644
--- a/util/getroot.c
+++ b/util/getroot.c
@@ -1322,7 +1322,7 @@ grub_util_get_dev_abstraction (const char *os_dev)
 static void
 pull_lvm_by_command (const char *os_dev)
 {
-  char *argv[6];
+  char *argv[7];
   int fd;
   pid_t pid;
   FILE *mdadm;
@@ -1355,8 +1355,9 @@ pull_lvm_by_command (const char *os_dev)
   argv[1] = (char *) "--options";
   argv[2] = (char *) "pv_name";
   argv[3] = (char *) "--noheadings";
-  argv[4] = vgname;
-  argv[5] = NULL;
+  argv[4] = (char *) "--nameprefixes";
+  argv[5] = vgname;
+  argv[6] = NULL;
 
   pid = exec_pipe (argv, &fd);
   free (vgname);
@@ -1376,10 +1377,19 @@ pull_lvm_by_command (const char *os_dev)
   while (getline (&buf, &len, mdadm) > 0)
     {
       char *ptr;
-      for (ptr = buf; ptr < buf + 2 && *ptr == ' '; ptr++);
+
+      grub_util_info ("vgs returned PV: %s", buf);
+
+      for (ptr = buf; *ptr == ' '; ptr++);
       if (*ptr == '\0')
        continue;
-      *(ptr + strlen (ptr) - 1) = '\0';
+      if (strncmp (buf, "LVM2_PV_NAME='", sizeof ("LVM2_PV_NAME='") - 1))
+       continue;
+      ptr = buf + sizeof ("LVM2_PV_NAME='") - 1;
+      if (*(buf + len - 1) != '\'')
+       continue;
+      *(buf + len - 1) = '\0';
+      /* FIXME can PV name contain "'"? */
       grub_util_pull_device (ptr);
     }
 
-- 
tg: (e1a892d..) u/strip-pv-trailing-blanks (depends on: master)