ali: executable file inclusion.

The "< file" construct tests if file is executable and begins with
the shell interpreter magic (#!/ or #! /).  If so, this file is
executed and its output is collected.  This provides a way for
building aliases on the fly.

* mh/mh_alias.l (buffer_ctx) <exec_p>: New member.
(exec_p): New static variable.
(push_source): If the file is executable and begins with
the "#!/" magic, run it and collect its output.
(pop_source): Use exec_p to decide how to close the file.
* mh/tests/ali.at: Test executable file inclusion.
* NEWS: Update.

-GNU mailutils NEWS -- history of user-visible changes. 2012-11-12
+GNU mailutils NEWS -- history of user-visible changes. 2013-02-16
 Copyright (C) 2002-2012 Free Software Foundation, Inc.
 Copyright (C) 2002-2012 Free Software Foundation, Inc.
 See the end of file for copying conditions.
 See the end of file for copying conditions.
 
 
@@ -203,6 +203,14 @@ option:
     "yes", the mailbox will be truncated after successful processing.
     "yes", the mailbox will be truncated after successful processing.
     If BOOL is "no", the source mailbox will not be truncated.
     If BOOL is "no", the source mailbox will not be truncated.
 
 
+** MH aliases
+
+The "< FILE" construct has been extended to allow for building the
+list of aliases on the fly.  If FILE is an executable file and its
+first line begins with a shell interpreter magic (#!/ or #! /), then
+instead of being included, such file is run using "/bin/sh -c", its
+output is collected and included in the aliases.
+    
 ** mailutils-config is deprecated.
 ** mailutils-config is deprecated.
 
 
 Use `mu cflags' and `mu ldflags' instead.  The mailutils-config is
 Use `mu cflags' and `mu ldflags' instead.  The mailutils-config is

@@ -219,10 +219,12 @@ struct buffer_ctx {
   int line;
   int line;
   ino_t i_node;
   ino_t i_node;
   FILE *yyin;
   FILE *yyin;
+  int exec_p;
   LEX_BUFFER_STATE state;
   LEX_BUFFER_STATE state;
 };
 };
 
 
 static struct buffer_ctx *context_stack;
 static struct buffer_ctx *context_stack;
+static int exec_p;
 
 
 static struct buffer_ctx *
 static struct buffer_ctx *
 ctx_lookup (ino_t ino)
 ctx_lookup (ino_t ino)
@@ -242,7 +244,8 @@ push_source (const char *name, int fail)
   struct buffer_ctx *ctx;
   struct buffer_ctx *ctx;
   struct stat st;
   struct stat st;
   char *filename;
   char *filename;
-
+  int ex = 0;
+  
   filename = mh_expand_name (NULL, name, 0);
   filename = mh_expand_name (NULL, name, 0);
   if (stat (filename, &st))
   if (stat (filename, &st))
     {
     {
@@ -251,7 +254,7 @@ push_source (const char *name, int fail)
       free (filename);
       free (filename);
       return 1;
       return 1;
     }
     }
-
+    
   if (ali_filename && st.st_ino == ali_source_inode)
   if (ali_filename && st.st_ino == ali_source_inode)
     {
     {
       ali_parse_error (_("recursive inclusion"));
       ali_parse_error (_("recursive inclusion"));
@@ -279,12 +282,35 @@ push_source (const char *name, int fail)
       free (filename);
       free (filename);
       return 1;
       return 1;
     }
     }
+  if (access (filename, X_OK) == 0)
+    {
+      char sig[4];
+
+      if (fread (sig, sizeof(sig), 1, fp) == 1 &&
+	  (memcmp(sig, "#!/", 3) == 0 ||
+	   memcmp(sig, "#! /", 4) == 0))
+	{
+	  ex = 1;
+	  fclose (fp);
+	  fp = popen (filename, "r");
+	  if (!fp)
+	    {
+	      ali_parse_error (_("can't execute `%s': %s"),
+			       filename, strerror (errno));
+	      free (filename);
+	      return 1;
+	    }
+	}
+      else
+	rewind (fp);
+    }
   
   
   /* Push current context */
   /* Push current context */
   if (ali_filename)
   if (ali_filename)
     {
     {
       ctx = mu_alloc (sizeof (*ctx));
       ctx = mu_alloc (sizeof (*ctx));
       ctx->filename = ali_filename;
       ctx->filename = ali_filename;
+      ctx->exec_p = exec_p;
       ctx->line = ali_line_num;
       ctx->line = ali_line_num;
       ctx->i_node = ali_source_inode;
       ctx->i_node = ali_source_inode;
       ctx->yyin = yyin;
       ctx->yyin = yyin;
@@ -307,6 +333,7 @@ push_source (const char *name, int fail)
   ali_filename = filename;
   ali_filename = filename;
   ali_line_num = 1;
   ali_line_num = 1;
   ali_source_inode = st.st_ino;
   ali_source_inode = st.st_ino;
+  exec_p = ex;
   return 0;
   return 0;
 }
 }
 
 
@@ -316,7 +343,7 @@ pop_source ()
   struct buffer_ctx *ctx;
   struct buffer_ctx *ctx;
 
 
   if (yyin)
   if (yyin)
-    fclose (yyin);
+    (exec_p ? pclose : fclose) (yyin);
 #ifndef FLEX_SCANNER
 #ifndef FLEX_SCANNER
   lex_delete_buffer (current_buffer);
   lex_delete_buffer (current_buffer);
 #endif
 #endif
@@ -332,6 +359,7 @@ pop_source ()
   ali_filename = context_stack->filename;
   ali_filename = context_stack->filename;
   ali_line_num = context_stack->line + 1; /* < line did not increment it */
   ali_line_num = context_stack->line + 1; /* < line did not increment it */
   ali_source_inode = context_stack->i_node;
   ali_source_inode = context_stack->i_node;
+  exec_p = context_stack->exec_p;
   RESTORE_BUFFER_STATE (context_stack->state);
   RESTORE_BUFFER_STATE (context_stack->state);
   ctx = context_stack->prev;
   ctx = context_stack->prev;
   free (context_stack);
   free (context_stack);

@@ -108,15 +108,19 @@ ali -list -a ./mh_aliases everybody
 [0],
 [0],
 [expout])
 [expout])
 
 
-MH_CHECK([ali: simple aliases],[ali00],[
+MH_CHECK([ali: executable file inlcusion],[ali02 ali-xinclude],[
+AT_DATA([Mail/ali.sh],[#! /bin/sh
+echo "admin: gray, jeff"
+])
+chmod +x Mail/ali.sh
 AT_DATA([mh_aliases],[
 AT_DATA([mh_aliases],[
-devel: gray, polak
-admin: gray, jeff
+devel: gray, polak, admin
+<ali.sh
 ])
 ])
 ali -a ./mh_aliases devel
 ali -a ./mh_aliases devel
 ],
 ],
 [0],
 [0],
-[gray, polak
+[gray, polak, gray, jeff
 ])
 ])
 
 
 m4_popdef[MH_KEYWORDS])
 m4_popdef[MH_KEYWORDS])