[libvirt] [PATCHv3] parthelper: fix compilation without optimization

[Eric Blake]

Daniel's patch works with gcc and CFLAGS containing -O (the
autoconf default), but fails with non-gcc or with other
CFLAGS (such as -g), since c-ctype.h declares c_isdigit as
a macro only for certain compilation settings.

* src/Makefile.am (libvirt_parthelper_LDFLAGS): Add gnulib
library, for when c_isdigit is not a macro.
* src/storage/parthelper.c (main): Avoid out-of-bounds
dereference, noticed by Jim Meyering.
---

change in v3: earlier code already guarantees that path is non-null
if we got this far, but not whether it is non-empty

 src/Makefile.am          |    2 +-
 src/storage/parthelper.c |    2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/Makefile.am b/src/Makefile.am
index 6bdf73c..2129960 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -1035,13 +1035,13 @@ if WITH_STORAGE_DISK
 if WITH_LIBVIRTD
 libexec_PROGRAMS += libvirt_parthelper

 libvirt_parthelper_SOURCES = $(STORAGE_HELPER_DISK_SOURCES)
 libvirt_parthelper_LDFLAGS = $(WARN_LDFLAGS) $(COVERAGE_LDFLAGS)
 libvirt_parthelper_LDADD = $(LIBPARTED_LIBS)
-libvirt_parthelper_CFLAGS =  $(LIBPARTED_CFLAGS)
+libvirt_parthelper_CFLAGS = $(LIBPARTED_CFLAGS) ../gnulib/lib/libgnu.la
 endif
 endif
 EXTRA_DIST += $(STORAGE_HELPER_DISK_SOURCES)


 if WITH_LXC
diff --git a/src/storage/parthelper.c b/src/storage/parthelper.c
index 28d88c9..ca74456 100644
--- a/src/storage/parthelper.c
+++ b/src/storage/parthelper.c
@@ -66,13 +66,13 @@ int main(int argc, char **argv)
     } else if (argc != 2) {
         fprintf(stderr, "syntax: %s DEVICE [-g]\n", argv[0]);
         return 1;
     }

     path = argv[1];
-    partsep = c_isdigit(path[strlen(path)-1]) ? "p" : "";
+    partsep = *path && c_isdigit(path[strlen(path)-1]) ? "p" : "";

     if ((dev = ped_device_get(path)) == NULL) {
         fprintf(stderr, "unable to access device %s\n", path);
         return 2;
     }

-- 
1.7.0.1