Upgrade licence to GPLv3+.

[userv.git] / process.c

diff --git a/process.c b/process.c
index c4a4809ed419774707be172ef2023b03ad8bf14d..fa8302f93c4e8b41b3a979686c8a4c7b40e96dcd 100644 (file)
--- a/process.c
+++ b/process.c
@@ -2,11 +2,14 @@
  * userv - process.c
  * daemon code to process one request (is parent of service process)
  *
- * Copyright (C)1996-1999 Ian Jackson
+ * userv is
+ * Copyright 1996-2017 Ian Jackson <ian@davenant.greenend.org.uk>.
+ * Copyright 2000      Ben Harris <bjh21@cam.ac.uk>
+ * Copyright 2016-2017 Peter Benie <pjb1008@cam.ac.uk>
  *
  * This is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
+ * the Free Software Foundation; either version 3 of the License, or
  * (at your option) any later version.
  *
  * This program is distributed in the hope that it will be useful, but
@@ -15,8 +18,7 @@
  * General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
- * along with userv; if not, write to the Free Software
- * Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ * along with userv; if not, see <http://www.gnu.org/licenses/>.
  */
 
 /*
@@ -443,6 +445,8 @@ static void receive_request(void) {
     assert(fdarray[fd].iswrite == -1);
     fdarray[fd].iswrite= (i>=request_mbuf.nreadfds);
   }
+  /* fdarray[].iswrite now set; rest is still blank
+   * (ie want reject read, no realfd holdfd). */
 
   assert(request_mbuf.nargs <= MAX_ARGSDEFVAR);
   argarray= xmalloc(sizeof(char*)*(request_mbuf.nargs));
@@ -482,6 +486,14 @@ static void establish_pipes(void) {
     if (unlink(pipepathbuf)) syscallerror("unlink pipe");
     if (close(tempfd)) syscallerror("close prelim fd onto pipe");
   }
+  /* Now fdarray[].realfd is pipe end for service in case service
+   * wants it.  If it's an input pipe, then .holdfd is the other
+   * (writing) end of the pipe - we keep it around so that the service
+   * doesn't get an apparently clean EOF if the caller disappears (eg
+   * due to a file read error) or the like (ie so that on disconnect
+   * we can guarantee to send the service SIGHUP before it gets EOF on
+   * the input fd).  Otherwise, .holdfd=-1.
+   */
 }
 
 static void groupnames(int ngids, gid_t *gids, const char ***names_r) {
@@ -645,7 +657,6 @@ static void check_fds(void) {
     case tokv_word_requirefd:
       if (fdarray[fd].realfd == -1)
        failure("file descriptor %d required but not provided",fd);
-      assert(fdarray[fd].holdfd == -1);
       /* fall through */
     case tokv_word_allowfd:
       if (fdarray[fd].realfd == -1) {
@@ -662,6 +673,10 @@ static void check_fds(void) {
       }
     }
   }
+  /* Now fdarray[].realfd is exactly what service wants: pipe end or
+   * /dev/null or -1.  If .realfd is not -1 then .holdfd may be the fd
+   * for the writing end of the corresponding pipe.
+   */
 }
 
 static void send_progress_ok(void) {