Simply reaping of dead processes

Let the kernel do the reaping, since we do not care about the exit code
anyway. This should also fix #151.

kitty/child-monitor.c

@@ -662,37 +662,11 @@ hangup(pid_t pid) {
     }
 }
 
-static pid_t pid_buf[MAX_CHILDREN] = {0};
-static size_t pid_buf_pos = 0;
-static pthread_t reap_thread;
-
-
-static void*
-reap(void *pid_p) {
-    set_thread_name("KittyReapChild");
-    pid_t pid = *((pid_t*)pid_p);
-    while(true) {
-        pid_t ret = waitpid(pid, NULL, 0);
-        if (ret != pid) {
-            if (errno == EINTR) continue;
-            fprintf(stderr, "Failed to reap child process with pid: %d with error: %s\n", pid, strerror(errno));
-        }
-        break;
-    }
-    return 0;
-}
 
 static inline void
 cleanup_child(ssize_t i) {
     close(children[i].fd);
     hangup(children[i].pid);
-    pid_buf[pid_buf_pos] = children[i].pid;
-    if (waitpid(pid_buf[pid_buf_pos], NULL, WNOHANG) != pid_buf[pid_buf_pos]) {
-        errno = 0;
-        int ret = pthread_create(&reap_thread, NULL, reap, pid_buf + pid_buf_pos);
-        if (ret != 0) perror("Failed to create thread to reap child");
-    }
-    pid_buf_pos = (pid_buf_pos + 1) % MAX_CHILDREN;
 }
 
 

kitty/main.py

@@ -5,6 +5,7 @@
 import argparse
 import locale
 import os
+import signal
 import sys
 from contextlib import contextmanager
 from gettext import gettext as _
@@ -235,11 +236,11 @@ def setup_profiling(args):
         exe = os.path.join(os.path.dirname(os.path.dirname(os.path.abspath(__file__))), 'kitty-profile')
         cg = '/tmp/kitty-profile.callgrind'
         print('Post processing profile data for', exe, '...')
-        subprocess.check_call(['pprof', '--callgrind', exe, '/tmp/kitty-profile.log'], stdout=open(cg, 'wb'))
+        subprocess.call(['pprof', '--callgrind', exe, '/tmp/kitty-profile.log'], stdout=open(cg, 'wb'))
         try:
             subprocess.Popen(['kcachegrind', cg])
         except FileNotFoundError:
-            subprocess.check_call(['pprof', '--text', exe, '/tmp/kitty-profile.log'])
+            subprocess.call(['pprof', '--text', exe, '/tmp/kitty-profile.log'])
             print('To view the graphical call data, use: kcachegrind', cg)
 
 
@@ -286,6 +287,9 @@ def main():
         raise SystemExit('GLFW initialization failed')
     try:
         with setup_profiling(args):
+            # Let the kernel take care of reaping zombie child processes
+            signal.signal(signal.SIGCHLD, signal.SIG_IGN)
             run_app(opts, args)
+            signal.signal(signal.SIGCHLD, signal.SIG_DFL)
     finally:
         glfw_terminate()

kitty/utils.py

@@ -165,7 +165,8 @@ def get_primary_selection():
         return ''  # There is no primary selection on OS X
     g = selection_clipboard_funcs()[0]
     if g is None:
-        ans = subprocess.check_output(['xsel', '-p'], stderr=subprocess.DEVNULL, stdin=subprocess.DEVNULL).decode('utf-8')
+        # We cannot use check_output as we set SIGCHLD to SIG_IGN
+        ans = subprocess.Popen(['xsel', '-p'], stderr=subprocess.DEVNULL, stdin=subprocess.DEVNULL, stdout=subprocess.PIPE).stdout.read().decode('utf-8')
         if ans:
             # Without this for some reason repeated pastes dont work
             set_primary_selection(ans)
@@ -192,7 +193,7 @@ def open_cmd(cmd, arg=None):
     if arg is not None:
         cmd = list(cmd)
         cmd.append(arg)
-    return subprocess.Popen(cmd, stdin=subprocess.DEVNULL, stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL).wait()
+    return subprocess.Popen(cmd, stdin=subprocess.DEVNULL, stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL)
 
 
 def open_url(url, program='default'):