Fixed possible dereference of null pointer

getpwuid() can return null. For example, Shun Sakuruba reported that
on Cray XE6 compute nodes have passwd.h, but users will not have
passwd entries.

Fixes #1301

Change-Id: I66e8064438fc02591629b0d381bc00afd06795c0

diff --git a/src/gmxlib/string2.c b/src/gmxlib/string2.c
index 1b02ff798bed23dd0acb5f2685e83287b345880f..eadbf21a591804e985e429c36f6aae463e883821 100644 (file)
--- a/src/gmxlib/string2.c
+++ b/src/gmxlib/string2.c
@@ -244,7 +244,8 @@ void nice_header (FILE *out, const char *fn)
     uid  = getuid();
     pw   = getpwuid(uid);
     gh   = gethostname(buf, 255);
-    user = pw->pw_name;
+    /* pw returns null on error (e.g. compute nodes lack /etc/passwd) */
+    user = pw ? pw->pw_name : unk;
 #else
     uid = 0;
     gh  = -1;