nightmaremail

commit c91e4f75fde4a5d5ba4bf0ceba1e9bef972f07f3
parent 612f784709e8c5a77cc48c6ba749eb1f92cf330c
Author: Flavio Curti <fcu-software@no-way.org>
Date:   Sat,  5 Dec 2020 19:23:02 +0100

Let QMAILQUEUE wrapper return custom error strings.

Original: qmail-queue-custom-error-v2.netqmail-1.05.patch

A common QMAILQUEUE use case is to prevent some messages from entering
the queue. We extend the qmail-queue(8) interface so that when rejecting
a message, a custom string can optionally be communicated to the caller
(for instance, qmail-smtpd). When this is desired, write to fd 6:

    "Dthis is a custom fatal error message"
      or
    "Zthis is a custom temporary failure message"

and exit 82.

An earlier version of this patch has been around since 2005. In 2007, it
switched from fd 4 to 6 in order to play well with qmail-qfilter.

Diffstat:
M
qmail.c
 | 
28
+++++++++++++++++++++++++++-
M
qmail.h
 | 
1
+

2 files changed, 28 insertions(+), 1 deletion(-)
diff --git a/qmail.c b/qmail.c
@@ -24,22 +24,32 @@ struct qmail *qq;
 {
   int pim[2];
   int pie[2];
+  int pierr[2];
 
   setup_qqargs();
 
   if (pipe(pim) == -1) return -1;
   if (pipe(pie) == -1) { close(pim[0]); close(pim[1]); return -1; }
+  if (pipe(pierr) == -1) {
+    close(pim[0]); close(pim[1]);
+    close(pie[0]); close(pie[1]);
+    close(pierr[0]); close(pierr[1]);
+    return -1;
+  }
  
   switch(qq->pid = fork()) {
     case -1:
+      close(pierr[0]); close(pierr[1]);
       close(pim[0]); close(pim[1]);
       close(pie[0]); close(pie[1]);
       return -1;
     case 0:
       close(pim[1]);
       close(pie[1]);
+      close(pierr[0]); /* we want to receive data */
       if (fd_move(0,pim[0]) == -1) _exit(120);
       if (fd_move(1,pie[0]) == -1) _exit(120);
+      if (fd_move(6,pierr[1]) == -1) _exit(120);
       if (chdir(auto_qmail) == -1) _exit(61);
       execv(*binqqargs,binqqargs);
       _exit(120);
@@ -47,6 +57,7 @@ struct qmail *qq;
 
   qq->fdm = pim[1]; close(pim[0]);
   qq->fde = pie[1]; close(pie[0]);
+  qq->fderr = pierr[0]; close(pierr[1]);
   substdio_fdbuf(&qq->ss,write,qq->fdm,qq->buf,sizeof(qq->buf));
   qq->flagerr = 0;
   return 0;
@@ -89,10 +100,22 @@ struct qmail *qq;
 {
   int wstat;
   int exitcode;
+  int match;
+  char ch;
+  static char errstr[256];
+  int len = 0;
 
   qmail_put(qq,"",1);
   if (!qq->flagerr) if (substdio_flush(&qq->ss) == -1) qq->flagerr = 1;
   close(qq->fde);
+  substdio_fdbuf(&qq->ss,read,qq->fderr,qq->buf,sizeof(qq->buf));
+  while( substdio_bget(&qq->ss,&ch,1) && len < 255){
+    errstr[len]=ch;
+    len++;
+  }
+  if (len > 0) errstr[len]='\0'; /* add str-term */
+
+  close(qq->fderr);
 
   if (wait_pid(&wstat,qq->pid) != qq->pid)
     return "Zqq waitpid surprise (#4.3.0)";
@@ -125,8 +148,11 @@ struct qmail *qq;
     case 81: return "Zqq internal bug (#4.3.0)";
     case 120: return "Zunable to exec qq (#4.3.0)";
     default:
+      if (exitcode == 82 && len > 2){
+        return errstr;
+      }
       if ((exitcode >= 11) && (exitcode <= 40))
-	return "Dqq permanent problem (#5.3.0)";
+        return "Dqq permanent problem (#5.3.0)";
       return "Zqq temporary problem (#4.3.0)";
   }
 }
diff --git a/qmail.h b/qmail.h
@@ -10,6 +10,7 @@ struct qmail {
   unsigned long pid;
   int fdm;
   int fde;
+  int fderr;
   substdio ss;
   char buf[1024];
 } ;