getaddrinfo: Fix error handling in gethosts [BZ #21915] [BZ #21922]

The old code uses errno as the primary indicator for success or
failure.  This is wrong because errno is only set for specific
combinations of the status return value and the h_errno variable.

1 files changed, 109 insertions, 0 deletions

diff --git a/nss/tst-nss-files-hosts-erange.c b/nss/tst-nss-files-hosts-erange.c
new file mode 100644
index 0000000000..beb7aa9fa0
--- /dev/null
+++ b/nss/tst-nss-files-hosts-erange.c
@@ -0,0 +1,109 @@
+/* Parse /etc/hosts in multi mode with a trailing long line (bug 21915).
+   Copyright (C) 2017 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+
+#include <dlfcn.h>
+#include <errno.h>
+#include <gnu/lib-names.h>
+#include <netdb.h>
+#include <nss.h>
+#include <support/check.h>
+#include <support/check_nss.h>
+#include <support/namespace.h>
+#include <support/test-driver.h>
+#include <support/xunistd.h>
+
+struct support_chroot *chroot_env;
+
+#define X10 "XXXXXXXXXX"
+#define X100 X10 X10 X10 X10 X10 X10 X10 X10 X10 X10
+#define X1000 X100 X100 X100 X100 X100 X100 X100 X100 X100 X100
+
+static void
+prepare (int argc, char **argv)
+{
+  chroot_env = support_chroot_create
+    ((struct support_chroot_configuration)
+     {
+       .resolv_conf = "",
+       .hosts =
+         "127.0.0.1   localhost localhost.localdomain\n"
+         "::1         localhost localhost.localdomain\n"
+         "192.0.2.1   example.com\n"
+         "#" X1000 X100 "\n",
+       .host_conf = "multi on\n",
+     });
+}
+
+static int
+do_test (void)
+{
+  support_become_root ();
+  if (!support_can_chroot ())
+    return EXIT_UNSUPPORTED;
+
+  __nss_configure_lookup ("hosts", "files");
+  if (dlopen (LIBNSS_FILES_SO, RTLD_LAZY) == NULL)
+    FAIL_EXIT1 ("could not load " LIBNSS_DNS_SO ": %s", dlerror ());
+
+  xchroot (chroot_env->path_chroot);
+
+  errno = ERANGE;
+  h_errno = NETDB_INTERNAL;
+  check_hostent ("gethostbyname example.com",
+                 gethostbyname ("example.com"),
+                 "name: example.com\n"
+                 "address: 192.0.2.1\n");
+  errno = ERANGE;
+  h_errno = NETDB_INTERNAL;
+  check_hostent ("gethostbyname2 AF_INET example.com",
+                 gethostbyname2 ("example.com", AF_INET),
+                 "name: example.com\n"
+                 "address: 192.0.2.1\n");
+  {
+    struct addrinfo hints =
+      {
+        .ai_family = AF_UNSPEC,
+        .ai_socktype = SOCK_STREAM,
+        .ai_protocol = IPPROTO_TCP,
+      };
+    errno = ERANGE;
+    h_errno = NETDB_INTERNAL;
+    struct addrinfo *ai;
+    int ret = getaddrinfo ("example.com", "80", &hints, &ai);
+    check_addrinfo ("example.com AF_UNSPEC", ai, ret,
+                    "address: STREAM/TCP 192.0.2.1 80\n");
+    if (ret == 0)
+      freeaddrinfo (ai);
+
+    hints.ai_family = AF_INET;
+    errno = ERANGE;
+    h_errno = NETDB_INTERNAL;
+    ret = getaddrinfo ("example.com", "80", &hints, &ai);
+    check_addrinfo ("example.com AF_INET", ai, ret,
+                    "address: STREAM/TCP 192.0.2.1 80\n");
+    if (ret == 0)
+      freeaddrinfo (ai);
+  }
+
+  support_chroot_free (chroot_env);
+  return 0;
+}
+
+#define PREPARE prepare
+#include <support/test-driver.c>