[Libvir] Avoid leak upon failed realloc

[Jim Meyering]

This matters only if/when this realloc call fails.  And then, only in
the small way that with this patch, there's a slightly better chance of
recovering from the low-memory condition.

2007-06-22  Jim Meyering  <jim at meyering.net>

	* qemud/driver.c (qemudMonitorCommand): Avoid leak upon failed realloc.

Index: qemud/driver.c
===================================================================
RCS file: /data/cvs/libvirt/qemud/driver.c,v
retrieving revision 1.21
diff -u -p -r1.21 driver.c
--- qemud/driver.c	15 Jun 2007 13:44:19 -0000	1.21
+++ qemud/driver.c	22 Jun 2007 09:43:59 -0000
@@ -75,6 +75,7 @@ int qemudMonitorCommand(struct qemud_ser
         for (;;) {
             char data[1024];
             int got = read(vm->monitor, data, sizeof(data));
+            char *b;

             if (got == 0) {
                 if (buf)
@@ -91,8 +92,11 @@ int qemudMonitorCommand(struct qemud_ser
                     free(buf);
                 return -1;
             }
-            if (!(buf = realloc(buf, size+got+1)))
+            if (!(b = realloc(buf, size+got+1))) {
+                free(buf);
                 return -1;
+            }
+            buf = b;
             memmove(buf+size, data, got);
             buf[size+got] = '\0';
             size += got;