From 4b19c2885bae85dee45ecfc3cfcd8d503d3f3e23 Mon Sep 17 00:00:00 2001
From: Ian Jackson <ijackson@chiark.greenend.org.uk>
Date: Sun, 22 Jan 2017 11:52:07 +0000
Subject: [PATCH 1/1] Cope with programs which set SIGCHLD to SIG_IGN.  (We
 assume they don't manipulate SIGCHLD on other threads, which is probably
 true.)  Patch from Marco d'Itri, slightly modified.  Closes:#765587.

---
 debian/changelog |  5 ++++-
 libauthbind.c    | 23 ++++++++++++++++++++++-
 2 files changed, 26 insertions(+), 2 deletions(-)

diff --git a/debian/changelog b/debian/changelog
index f3e2c6b..1356606 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -1,5 +1,8 @@
-authbind (2.1.2~~iwj) unstable; urgency=low
+authbind (2.1.2) unstable; urgency=low
 
+  * Cope with programs which set SIGCHLD to SIG_IGN.  (We assume
+    they don't manipulate SIGCHLD on other threads, which is probably
+    true.)  Patch from Marco d'Itri, slightly modified.  Closes:#765587.
   * Fix one-letter typo in previous changelog entry.
 
  --
diff --git a/libauthbind.c b/libauthbind.c
index a685ce3..42630e4 100644
--- a/libauthbind.c
+++ b/libauthbind.c
@@ -146,9 +146,10 @@ int bind(int fd, const struct sockaddr *addr, socklen_t addrlen) {
   pid_t child, rchild;
   char portarg[5], addrarg[33];
   const char *afarg;
-  int i, r, status;
+  int i, r, status, restore_sigchild;
   const int *evilsignal;
   sigset_t block, saved;
+  struct sigaction old_sigchild;
   unsigned int portval;
 
   switch (addr->sa_family) {
@@ -195,6 +196,18 @@ int bind(int fd, const struct sockaddr *addr, socklen_t addrlen) {
   sprintf(portarg,"%04x",
 	  portval&0x0ffff);
 
+  restore_sigchild= 0;
+  if (sigaction(SIGCHLD,NULL,&old_sigchild)) return -1;
+  if (old_sigchild.sa_handler == SIG_IGN) {
+    struct sigaction new_sigchild;
+
+    new_sigchild.sa_handler= SIG_DFL;
+    sigemptyset(&new_sigchild.sa_mask);
+    new_sigchild.sa_flags= 0;
+    if (sigaction(SIGCHLD,&new_sigchild,&old_sigchild)) return -1;
+    restore_sigchild= 1;
+  }
+
   child= fork(); if (child==-1) goto x_err;
 
   if (!child) {
@@ -228,5 +241,13 @@ x_err:
   r= -1;
 x:
   if (sigprocmask(SIG_SETMASK,&saved,0)) abort();
+  if (restore_sigchild) {
+    if (sigaction(SIGCHLD,&old_sigchild,NULL)) return -1;
+    if (old_sigchild.sa_handler == SIG_IGN) {
+      int discard;
+      while (waitpid(-1, &discard, WNOHANG) > 0)
+	;
+    }
+  }
   return r;
 }
-- 
2.30.2