From f854583872ea416e214bf13d9e15c3bfd4839c69 Mon Sep 17 00:00:00 2001
From: Chris Kuehl <ckuehl@ocf.berkeley.edu>
Date: Mon, 1 Aug 2016 10:24:00 -0700
Subject: [PATCH] Fixes for FreeBSD kernel

---
 dumb-init.c         | 11 +++++++++++
 testing/__init__.py | 18 +++++++++++-------
 tests/tty_test.py   |  2 +-
 3 files changed, 23 insertions(+), 8 deletions(-)

diff --git a/dumb-init.c b/dumb-init.c
index 6d713e3..cb0cbec 100644
--- a/dumb-init.c
+++ b/dumb-init.c
@@ -32,6 +32,7 @@
 
 // Signals we care about are numbered from 1 to 31, inclusive.
 // (32 and above are real-time signals.)
+// TODO: this is likely not portable outside of Linux, or on strange architectures
 #define MAXSIG 31
 
 // Indices are one-indexed (signal 1 is at index 1). Index zero is unused.
@@ -233,12 +234,22 @@ char **parse_command(int argc, char *argv[]) {
     return &argv[optind];
 }
 
+// A dummy signal handler used for signals we care about.
+// On the FreeBSD kernel, ignored signals cannot be waited on by `sigwait` (but
+// they can be on Linux). We must provide a dummy handler.
+// https://lists.freebsd.org/pipermail/freebsd-ports/2009-October/057340.html
+void dummy(int signum) {}
+
 int main(int argc, char *argv[]) {
     char **cmd = parse_command(argc, argv);
     sigset_t all_signals;
     sigfillset(&all_signals);
     sigprocmask(SIG_BLOCK, &all_signals, NULL);
 
+    int i = 0;
+    for (i = 1; i <= MAXSIG; i++)
+        signal(i, dummy);
+
     child_pid = fork();
     if (child_pid < 0) {
         PRINTERR("Unable to fork. Exiting.\n");
diff --git a/testing/__init__.py b/testing/__init__.py
index 3582c88..ef2d543 100644
--- a/testing/__init__.py
+++ b/testing/__init__.py
@@ -48,13 +48,17 @@ def print_signals(args=()):
 
 def child_pids(pid):
     """Return a list of direct child PIDs for the given PID."""
-    pid = str(pid)
-    tasks = LocalPath('/proc').join(pid, 'task').listdir()
-    return set(
-        int(child_pid)
-        for task in tasks
-        for child_pid in task.join('children').read().split()
-    )
+    children = set()
+    for p in LocalPath('/proc').listdir():
+        stat = p.join('stat')
+        if stat.isfile():
+            stat = stat.open().read()
+            m = re.match('^\d+ \([^\)]+\) [a-zA-Z] (\d+) ', stat)
+            assert m, stat
+            ppid = int(m.group(1))
+            if ppid == pid:
+                children.add(int(p.basename))
+    return children
 
 
 def pid_tree(pid):
diff --git a/tests/tty_test.py b/tests/tty_test.py
index 16fccf8..23f6a5c 100644
--- a/tests/tty_test.py
+++ b/tests/tty_test.py
@@ -29,7 +29,7 @@ def readall(fd):
                 return result
             else:
                 raise
-        if chunk == '':
+        if chunk == b'':
             return result
         else:
             result += chunk