[PATCH] post-receive-email: do not call sendmail if no mail was generated

[Lars Noschinski <lars@public.noschinski.de>]

contrib/hooks/post-receive-email used to call the send_mail function
(and thus, /usr/sbin/sendmail), even if generate_mail generated no
output.  This is problematic, as the sendmail binary provided by exim4
generates an error mail if provided with an empty input.

Therefore, we now read one line ourselves and use the result to decide
if we really want to call /usr/sbin/sendmail.
---
 contrib/hooks/post-receive-email |   11 +++++++++++
 1 files changed, 11 insertions(+), 0 deletions(-)

Two things changed:

 - we do not read the whole mail in a shell variable
 - the decision whether to call sendmail is based on the output generated
   by generate_mail, not its return code

diff --git a/contrib/hooks/post-receive-email b/contrib/hooks/post-receive-email
index 2a66063..c855c31 100755
--- a/contrib/hooks/post-receive-email
+++ b/contrib/hooks/post-receive-email
@@ -637,6 +637,16 @@ show_new_revisions()
 
 send_mail()
 {
+	OIFS=$IFS
+	IFS='
+'
+	read FIRSTLINE || exit 1
+	(printf $FIRSTLINE'\n'; cat) | call_sendmail
+	IFS=$OLD_IFS
+}
+
+call_sendmail()
+{
 	if [ -n "$envelopesender" ]; then
 		/usr/sbin/sendmail -t -f "$envelopesender"
 	else
@@ -644,6 +654,7 @@ send_mail()
 	fi
 }
 
+
 # ---------------------------- main()
 
 # --- Constants
-- 
1.6.3.3