[binutils-gdb] libctf: allow ctf_type_lname of a null pointer.

[gdb-buildbot@sergiodj.net]

*** TEST RESULTS FOR COMMIT 1a6ab13e712348c59c2757457b9f913a333f3c92 ***

commit 1a6ab13e712348c59c2757457b9f913a333f3c92
Author:     Nick Alcock <nick.alcock@oracle.com>
AuthorDate: Thu Aug 8 16:53:48 2019 +0100
Commit:     Nick Alcock <nick.alcock@oracle.com>
CommitDate: Thu Oct 3 17:04:56 2019 +0100

    libctf: allow ctf_type_lname of a null pointer.
    
    The code was meant to handle this, but accidentally dereferenced the
    null pointer before checking it for nullity.
    
    v5: fix tabdamage.
    
    libctf/
            * ctf-types.c (ctf_type_name): Don't strlen a potentially-
            null pointer.

diff --git a/libctf/ChangeLog b/libctf/ChangeLog
index 106955385d..8f41ece32b 100644
--- a/libctf/ChangeLog
+++ b/libctf/ChangeLog
@@ -1,3 +1,8 @@
+2019-08-08  Nick Alcock  <nick.alcock@oracle.com>
+
+	* ctf-types.c (ctf_type_name): Don't strlen a potentially-
+	null pointer.
+
 2019-08-07  Nick Alcock  <nick.alcock@oracle.com>
 
 	* ctf-impl.h (ctf_file_t) <ctf_add_processing>: New.
diff --git a/libctf/ctf-types.c b/libctf/ctf-types.c
index 6e67762234..ec221d7349 100644
--- a/libctf/ctf-types.c
+++ b/libctf/ctf-types.c
@@ -438,11 +438,12 @@ ssize_t
 ctf_type_lname (ctf_file_t *fp, ctf_id_t type, char *buf, size_t len)
 {
   char *str = ctf_type_aname (fp, type);
-  size_t slen = strlen (str);
+  size_t slen;
 
   if (str == NULL)
     return CTF_ERR;             /* errno is set for us */
 
+  slen = strlen (str);
   snprintf (buf, len, "%s", str);
   free (str);