[libvirt] [PATCH 1/1] [RFC] lvm storage backend: handle command_names=1 in lvm.conf

[Eric Blake]

On 09/15/2011 08:17 AM, Serge E. Hallyn wrote:
> If the regexes supported (?:pvs)?, then we could handle this by
> optionally matching but not returning the initial command name.  But it
> doesn't.  So add a new char* argument to
> virStorageBackendRunProgRegex().  If that argument is NULL then we act
> as usual.  Otherwise, if the string at that argument is found at the
> start of a returned line, we drop that before running the regex.

Yeah, ignoring a prefix seems like the right approach, since we can't 
rely on non-capturing regex extensions.

>
> +        p = line;
> +        /* if cmd_to_ignore is specified, then ignore it */
> +        if (strncmp(line, cmd_to_ignore, strlen(cmd_to_ignore)) == 0)

'make syntax-check' should have called you on this; you should be using 
STRPREFIX here.  Something like (untested):

diff --git i/src/storage/storage_backend.c w/src/storage/storage_backend.c
index 7a352da..3415918 100644
--- i/src/storage/storage_backend.c
+++ w/src/storage/storage_backend.c
@@ -1460,16 +1460,17 @@ 
virStorageBackendRunProgRegex(virStoragePoolObjPtr pool,
      }

      while (fgets(line, sizeof(line), list) != NULL) {
-        char *p;
+        char *p = NULL;
          /* Strip trailing newline */
          int len = strlen(line);
          if (len && line[len-1] == '\n')
              line[len-1] = '\0';

-        p = line;
          /* if cmd_to_ignore is specified, then ignore it */
-        if (strncmp(line, cmd_to_ignore, strlen(cmd_to_ignore)) == 0)
-            p += strlen(cmd_to_ignore);
+        if (cmd_to_ignore)
+            p = STRSKIP(line, cmd_to_ignore);
+        if (!p)
+            p = line;

          for (i = 0 ; i <= maxReg && i < nregex ; i++) {
              if (regexec(&reg[i], p, nvars[i]+1, vars, 0) == 0) {


-- 
Eric Blake   eblake at redhat.com    +1-801-349-2682
Libvirt virtualization library http://libvirt.org