[PATCH] support_chroot_create: Add support for /etc/hosts, /etc/host.conf

[fweimer at redhat dot com (Florian Weimer)]

2017-08-08  Florian Weimer  <fweimer@redhat.com>

	* support/namespace.h (struct support_chroot_configuration): Add
	hosts, host_conf.
	(struct support_chroot): Add path_hosts, path_host_conf.
	* support/support_chroot.c (write_file): New function.
	(support_chroot_create): Call it to process /etc/resolv.conf,
	/etc/hosts, /etc/host.conf.
	(support_chroot_free): Update.

diff --git a/support/namespace.h b/support/namespace.h
index 859c2fd..9eddb1a 100644
--- a/support/namespace.h
+++ b/support/namespace.h
@@ -66,7 +66,9 @@ struct support_chroot_configuration
 {
   /* File contents.  The files are not created if the field is
      NULL.  */
-  const char *resolv_conf;
+  const char *resolv_conf;      /* /etc/resolv.conf.  */
+  const char *hosts;            /* /etc/hosts.  */
+  const char *host_conf;        /* /etc/host.conf.  */
 };
 
 /* The result of the creation of a chroot.  */
@@ -78,8 +80,11 @@ struct support_chroot
   /* Path to the chroot directory.  */
   char *path_chroot;
 
-  /* Path to the /etc/resolv.conf file.  */
-  char *path_resolv_conf;
+  /* Paths to files in the chroot.  These are absolute and outside of
+     the chroot.  */
+  char *path_resolv_conf;       /* /etc/resolv.conf.  */
+  char *path_hosts;             /* /etc/hosts.  */
+  char *path_host_conf;         /* /etc/host.conf.  */
 };
 
 /* Create a chroot environment.  The returned data should be freed
diff --git a/support/support_chroot.c b/support/support_chroot.c
index c0807b3..f3ef551 100644
--- a/support/support_chroot.c
+++ b/support/support_chroot.c
@@ -24,6 +24,23 @@
 #include <support/test-driver.h>
 #include <support/xunistd.h>
 
+/* If CONTENTS is not NULL, write it to the file at DIRECTORY/RELPATH,
+   and store the name in *ABSPATH.  If CONTENTS is NULL, store NULL in
+   *ABSPATH.  */
+static void
+write_file (const char *directory, const char *relpath, const char *contents,
+            char **abspath)
+{
+  if (contents != NULL)
+    {
+      *abspath = xasprintf ("%s/%s", directory, relpath);
+      add_temp_file (*abspath);
+      support_write_file_string (*abspath, contents);
+    }
+  else
+    *abspath = NULL;
+}
+
 struct support_chroot *
 support_chroot_create (struct support_chroot_configuration conf)
 {
@@ -39,15 +56,10 @@ support_chroot_create (struct support_chroot_configuration conf)
   xmkdir (path_etc, 0777);
   add_temp_file (path_etc);
 
-  if (conf.resolv_conf != NULL)
-    {
-      /* Create an empty resolv.conf file.  */
-      chroot->path_resolv_conf = xasprintf ("%s/resolv.conf", path_etc);
-      add_temp_file (chroot->path_resolv_conf);
-      support_write_file_string (chroot->path_resolv_conf, conf.resolv_conf);
-    }
-  else
-    chroot->path_resolv_conf = NULL;
+  write_file (path_etc, "resolv.conf", conf.resolv_conf,
+              &chroot->path_resolv_conf);
+  write_file (path_etc, "hosts", conf.hosts, &chroot->path_hosts);
+  write_file (path_etc, "host.conf", conf.host_conf, &chroot->path_host_conf);
 
   free (path_etc);
 
@@ -67,5 +79,7 @@ support_chroot_free (struct support_chroot *chroot)
 {
   free (chroot->path_chroot);
   free (chroot->path_resolv_conf);
+  free (chroot->path_hosts);
+  free (chroot->path_host_conf);
   free (chroot);
 }