Fix up pointer issues with lib/libkvm

In particular,
- avoid dereferencing NULL pointers
- test pointers against NULL, not 0
- test for errout == NULL in the top-level functions (kvm_open, kvm_openfiles,
  kvm_open2, etc)
- Replace a realloc and free on failure with reallocf

Found with: devel/cocchinelle

Differential Revision: https://reviews.freebsd.org/D5954
MFC after: 1 week
Reviewed by: jhb
Sponsored by: EMC / Isilon Storage Division

1 files changed, 1 insertions, 1 deletions

diff --git a/lib/libkvm/kvm_minidump_mips.c b/lib/libkvm/kvm_minidump_mips.c
index 997b70d..97b0824 100644
--- a/lib/libkvm/kvm_minidump_mips.c
+++ b/lib/libkvm/kvm_minidump_mips.c
@@ -89,7 +89,7 @@ _mips_minidump_initvtop(kvm_t *kd)
 	off_t off;
 
 	vmst = _kvm_malloc(kd, sizeof(*vmst));
-	if (vmst == 0) {
+	if (vmst == NULL) {
 		_kvm_err(kd, kd->program, "cannot allocate vm");
 		return (-1);
 	}