Don't access line[-1] for a zero-length "line" from fgets.

A NUL byte at beginning of input, or just after a newline
would provoke an invalid buf[-1] access (possible segfault).
* src/libvirt.c (virConnectAuthCallbackDefault):

ChangeLog

+Mon Jan 21 15:03:04 CET 2008  Jim Meyering  <meyering@redhat.com>
+
+	Don't access line[-1] for a zero-length "line" from fgets.
+	A NUL byte at beginning of input, or just after a newline
+	would provoke an invalid buf[-1] access (possible segfault).
+	* src/libvirt.c (virConnectAuthCallbackDefault):
+
 Mon Jan 21 09:25:12 CET 2008 Daniel Veillard <veillard@redhat.com>
 
 	* src/xml-internal.c: apply patch from Hiroyuki Kaguchi to
@@ -27,7 +34,24 @@ Sat Jan 19 13:32:22 EST 2008 Daniel P. Berrange <berrange@redhat.com>
 	src/xend_internal.c: Use generic VIR_DEBUG macro for logging.
 	Enable debug when env var LIBVIRT_DEBUG=1
 
-Tue Jan 15 16:25:57 CET  Jim Meyering  <meyering@redhat.com>
+Thu Jan 17 23:12:42 CET 2008  Jim Meyering  <meyering@redhat.com>
+
+	Handle PyTuple_New's malloc failure.
+	* python/libvir.c (libvirt_virDomainBlockStats): Handle a NULL
+	return from PyTuple_New.
+	(libvirt_virDomainInterfaceStats, libvirt_virGetLastError): Likewise.
+	(libvirt_virConnGetLastError): Likewise.
+
+	Factor out some duplication.
+	* python/libvir.c (VIR_PY_NONE): New macro, to encapsulate
+	a common two-statement sequence.
+	Replace all such 2-stmt sequences.
+
+	Avoid format string warnings.
+	* src/virsh.c: Add "%s" where needed.
+	* src/proxy_internal.c: Likewise.
+
+Tue Jan 15 16:25:57 CET 2008  Jim Meyering  <meyering@redhat.com>
 
 	* docs/examples/examples.xml: Regenerate, now that *.c file names
 	are sorted.

src/libvirt.c

@@ -70,6 +70,7 @@ static int virConnectAuthCallbackDefault(virConnectCredentialPtr cred,
     for (i = 0 ; i < ncred ; i++) {
         char buf[1024];
         char *bufptr = buf;
+        size_t len;
 
         if (printf("%s:", cred[i].prompt) < 0)
             return -1;
@@ -88,8 +89,9 @@ static int virConnectAuthCallbackDefault(virConnectCredentialPtr cred,
                 }
                 return -1;
             }
-            if (buf[strlen(buf)-1] == '\n')
-                buf[strlen(buf)-1] = '\0';
+            len = strlen(buf);
+            if (len != 0 && buf[len-1] == '\n')
+                buf[len-1] = '\0';
             break;
 
         case VIR_CRED_PASSPHRASE: