* mailbox/cfg_driver.c (mu_cfg_tree_reduce): Format parse tree

before scanning the tree.
* mailbox/cfg_parser.y (block rule): Accept empty blocks.
(parse_param): bail out if callback is not declared when it
should.
* mailbox/daemon.c (mu_daemon_create_pidfile)
(mu_daemon_remove_pidfile): If running with UID=0 and EUID != 0,
temporarily switch to EUID=0 for accessing pidfile (when
creating or deleting).

+2008-11-15  Sergey Poznyakoff  <gray@gnu.org.ua>
+
+	* mailbox/cfg_driver.c (mu_cfg_tree_reduce): Format parse tree
+	before scanning the tree.
+	* mailbox/cfg_parser.y (block rule): Accept empty blocks.
+	(parse_param): bail out if callback is not declared when it
+	should.
+	* mailbox/daemon.c (mu_daemon_create_pidfile)
+	(mu_daemon_remove_pidfile): If running with UID=0 and EUID != 0,
+	temporarily switch to EUID=0 for accessing pidfile (when
+	creating or deleting).
+
 2008-11-12  Sergey Poznyakoff  <gray@gnu.org.ua>
 
 	* mailbox/cfg_parser.y (mu_cfg_format_error): Raise

@@ -581,6 +581,16 @@ mu_cfg_tree_reduce (mu_cfg_tree_t *parse_tree, const char *progname,
 {
   int rc = 0;
   
+  if (flags & MU_PARSE_CONFIG_DUMP)
+    {
+      mu_stream_t stream;
+      mu_stdio_stream_create (&stream, stderr,
+ 			      MU_STREAM_NO_CHECK|MU_STREAM_NO_CLOSE);
+      mu_stream_open (stream);
+      mu_cfg_format_parse_tree (stream, parse_tree);
+      mu_stream_destroy (&stream, NULL);
+    }
+
   if (root_container)
     {
       struct include_data idata;
@@ -598,16 +608,6 @@ mu_cfg_tree_reduce (mu_cfg_tree_t *parse_tree, const char *progname,
       mu_config_destroy_container (&cont);
     }
 
-  if (flags & MU_PARSE_CONFIG_DUMP)
-    {
-      mu_stream_t stream;
-      mu_stdio_stream_create (&stream, stderr,
- 			      MU_STREAM_NO_CHECK|MU_STREAM_NO_CLOSE);
-      mu_stream_open (stream);
-      mu_cfg_format_parse_tree (stream, parse_tree);
-      mu_stream_destroy (&stream, NULL);
-    }
-
   return rc;
 }
 

@@ -224,7 +224,14 @@ simple  : ident vallist ';'
 	  }
         ;
 
-block   : ident tag '{' stmtlist '}' opt_sc
+block   : ident tag '{' '}' opt_sc
+          {
+	    $$ = mu_cfg_alloc_node (mu_cfg_node_tag, &$1.locus,
+				    $1.name, $2,
+				    NULL);
+	    
+	  }
+        | ident tag '{' stmtlist '}' opt_sc
 	  {
 	    $$ = mu_cfg_alloc_node (mu_cfg_node_tag, &$1.locus,
 				    $1.name, $2,
@@ -1126,6 +1133,13 @@ parse_param (struct scan_tree_data *sdata, const mu_cfg_node_t *node)
     {
       mu_debug_set_locus (sdata->tree->debug, node->locus.file,
 			  node->locus.line);
+      if (!param->callback)
+	{
+	  _mu_cfg_perror (sdata->tree->debug, &node->locus,
+			  _("INTERNAL ERROR: %s: callback not defined"),
+			  node->tag);
+	  abort ();
+	}
       if (param->callback (sdata->tree->debug, tgt, node->label))
 	return 1;
       

@@ -30,41 +30,115 @@
 
 #include <mailutils/daemon.h>
 #include <mailutils/errno.h>
+#include <mailutils/error.h>
+#include <mailutils/nls.h>
 #include <mu_umaxtostr.h>
 
 static char *pidfile;
 static pid_t current_pid;
 
+/* Return 0 if DIR is writable for EUID/EGID.
+   Otherwise, return error code. */
+static int
+ewraccess (const char *dir)
+{
+  struct stat st;
+  if (stat (dir, &st))
+    return errno;
+  if ((st.st_mode & S_IWOTH)
+      || (st.st_gid == getegid () && (st.st_mode & S_IWGRP))
+      || (st.st_uid == geteuid () && (st.st_mode & S_IWUSR)))
+    return 0;
+  else
+    return EACCES;
+}
+
+/* Return 0 if DIR is writable. If necessary and possible, raise to
+   EUID 0, in that case return prior EUID in the memory location pointed to
+   by PUID. */
+static int
+access_dir (const char *dir, uid_t *puid)
+{
+  int ec = ewraccess (dir);
+  if (ec)
+    {
+      if (ec == EACCES && access (dir, W_OK) == 0)
+	{
+	  uid_t uid = geteuid ();
+	  /* See if we can become root */
+	  if (uid && getuid () == 0 && seteuid (0) == 0)
+	    {
+	      *puid = uid;
+	      return 0;
+	    }
+	}
+    }
+  return ec;
+}
+
 int
 mu_daemon_create_pidfile (const char *filename)
 {
+  char *p;
   const char *pid_string; 
   int fd;
+  uid_t uid = 0;
+  int rc;
   
   if (filename[0] != '/')
-    {
-      return EINVAL; /* failure */
-    }
+    return EINVAL;
 
   if (pidfile)
     free (pidfile);
   pidfile = strdup (filename);
+  if (!pidfile)
+    return ENOMEM;
+
+  /* Determine the hosting directory name */
+  p = strrchr (pidfile, '/');
+  if (pidfile == p)
+    {
+      free (pidfile);
+      pidfile = NULL;
+      /* Sorry, pidfiles in root dir are not allowed */
+      return EINVAL;
+    }
+  /* Check if we have write access to the directory */
+  *p = 0;
+  rc = access_dir (pidfile, &uid);
+  if (rc)
+    {
+      /* Nope, clean up and return */
+      free (pidfile);
+      pidfile = NULL;
+      return rc;
+    }
+
+  /* Restore directory separator */
+  *p = '/';
     
   unlink (pidfile);
   current_pid = getpid ();
   
-  if ((fd = open (pidfile, O_WRONLY | O_CREAT
-		  | O_TRUNC | O_EXCL, 0644)) == -1)
+  if ((fd = open (pidfile, O_WRONLY | O_CREAT | O_TRUNC | O_EXCL, 0644)) != -1)
     {
-      return errno; /* failure */
-    }
-  
       pid_string = mu_umaxtostr (0, current_pid);
       write (fd, pid_string, strlen (pid_string));
       close (fd);
-  
       atexit (mu_daemon_remove_pidfile);
-  return 0;
+    }
+  else
+    {
+      rc = errno;
+      free (pidfile);
+      pidfile = NULL;
+    }
+
+  /* Restore previous EUID value. */
+  if (uid)
+    seteuid (uid);
+  
+  return rc;
 }
 
 void
@@ -72,7 +146,32 @@ mu_daemon_remove_pidfile (void)
 {
   if (getpid () == current_pid)
     {
-      unlink (pidfile);
+      int rc;
+      uid_t uid = 0;
+
+      /* Determine the hosting directory name */
+      char *p = strrchr (pidfile, '/');
+      if (pidfile == p)
+	{
+	  /* Should not happen */
+	  abort ();
+	}
+      /* Check if we have write access to the directory */
+      *p = 0;
+      rc = access_dir (pidfile, &uid);
+      *p = '/';
+      if (rc == 0)
+	{
+	  if (unlink (pidfile) && errno != ENOENT)
+	    rc = errno;
+	  else
+	    rc = 0;
+	}
+      
+      if (rc)
+	mu_error (_("cannot remove pidfile %s: %s"),
+		  pidfile, mu_strerror (rc));
+
       free (pidfile);
       pidfile = NULL;
     }