hurd: fix gethostname(NULL, 0)

	* hurd/get-host.c (_hurd_get_host_config): Also check that more == 0
	before assuming that the file is empty.  Avoid testing buffer content
	when nread == 0.

diff --git a/ChangeLog b/ChangeLog
index 3e064fb..c40ee5d 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2017-09-07  Samuel Thibault  <samuel.thibault@ens-lyon.org>
+
+       * hurd/get-host.c (_hurd_get_host_config): Also check that more == 0
+       before assuming that the file is empty.  Avoid testing buffer content
+       when nread == 0.
+
 2017-09-06  Adhemerval Zanella  <adhemerval.zanella@linaro.org>
 
        [BZ #18858]

diff --git a/hurd/get-host.c b/hurd/get-host.c
index be8345f..e5d0539 100644 (file)
--- a/hurd/get-host.c
+++ b/hurd/get-host.c
@@ -65,7 +65,7 @@ _hurd_get_host_config (const char *item, char *buf, size_t buflen)
     }
 
   /* If the file is empty, give an empty value.  */
-  if (nread == 0)
+  if (nread == 0 && more == 0)
     {
       if (buflen != 0)
        *buf = '\0';
@@ -80,7 +80,7 @@ _hurd_get_host_config (const char *item, char *buf, size_t buflen)
   if (nread < buflen)
     buf[nread] = '\0';
   else
-    if (buf[nread - 1] != '\0')
+    if (nread != 0 && buf[nread - 1] != '\0')
       more = 1;
 
   if (more)