New files reaper.h and reaper.c.

Rev: src/Makefile.in:1.25
Rev: src/reaper.c:1.1
Rev: src/reaper.h:1.1

src/Makefile.in

@@ -45,7 +45,7 @@ COMMON_SRCS = alist.c atoms.c bignum.c channel.c \
 
 CLIENT_SRCS = lsh.c client.c client_keyexchange.c \
 	client_password.c client_userauth.c
-SERVER_SRCS = lshd.c server.c server_keyexchange.c\
+SERVER_SRCS = lshd.c reaper.c server.c server_keyexchange.c\
 	server_password.c server_userauth.c
 
 SRCS = $(COMMON_SRCS) $(CLIENT_SRCS) $(SERVER_SRCS)

src/reaper.c

+/* reaper.c
+ *
+ * Handle child processes.
+ *
+ * $Id$
+ */
+
+/* lsh, an implementation of the ssh protocol
+ *
+ * Copyright (C) 1998 Niels Mller
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include "reaper.h"
+
+#include "alist.h"
+#include "werror.h"
+#include "xalloc.h"
+
+#include <assert.h>
+#include <string.h>
+
+#include <errno.h>
+#include <signal.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+
+static sig_atomic_t halloween;
+
+static void child_handler(int signum)
+{
+  assert(signum == SIGCHLD);
+
+  halloween = 1;
+}
+
+struct reaper
+{
+  struct reap super;
+
+  /* Mapping of from pids to exit-callbacks. */
+  /* NOTE: This assumes that a pid_t fits in an int. */
+  struct alist *children;
+};
+
+static void do_reap(struct reap *c,
+		    pid_t pid, struct exit_callback *callback)
+{
+  struct reaper *closure = (struct reaper *) c;
+
+  MDEBUG(closure);
+
+  assert(!ALIST_GET(closure->children, pid));
+
+  ALIST_SET(closure->children, pid, callback);
+}
+  
+/* FIXME: Use an alist of pids->callbacks */
+static void reap(struct reaper *r)
+{
+  pid_t pid;
+  int status;
+
+  /* We must reset this flag before reaping the zoombies. */
+  halloween = 0;
+  
+  while( (pid = waitpid(-1, &status, WNOHANG)) )
+    {
+      if (pid > 0)
+	{
+	  int signaled;
+	  int value;
+	  int core;
+	  struct exit_callback *callback;
+	  
+	  if (WIFEXITED(status))
+	    {
+	      verbose("Child %d died with exit code %d.\n",
+		      pid, WEXITSTATUS(status));
+	      signaled = 0;
+	      core = 0;
+	      value = WEXITSTATUS(status);
+	    }
+	  else if (WIFSIGNALED(status))
+	    {
+	      verbose("Child %d killed by signal %d.\n",
+		      pid, WTERMSIG(status));
+	      signaled = 1;
+	      core = !!WCOREDUMP(status);
+	      value = WTERMSIG(status);
+	    }
+	  else
+	    fatal("Child died, but neither WIFEXITED or WIFSIGNALED is true.\n");
+
+	  callback = ALIST_GET(r->children, pid);
+	  
+	  if (callback)
+	    {
+	      ALIST_SET(r->children, pid, 0);
+	      EXIT_CALLBACK(callback, signaled, core, value);
+	    }
+	  else
+	    {
+	      if (WIFSIGNALED(status))
+		werror("Unregistered child %d killed by signal %d.\n",
+		       pid, value);
+	      else
+		werror("Unregistered child %d died with exit status %d.\n",
+		       pid, value);
+	    }
+	}
+      else switch(errno)
+	{
+	case EINTR:
+	  werror("reaper.c: waitpid() returned EINTR.\n");
+	  break;
+	case ECHILD:
+	  /* No more child processes */
+	  return;
+	default:
+	  fatal("reaper.c: waitpid failed (errno = %d), %s\n",
+		errno, strerror(errno));
+	}
+    }
+}
+
+struct reaper *make_reaper(void)
+{
+  struct reaper *closure;
+
+  NEW(closure);
+  closure->super.reap = do_reap;
+  closure->children = make_linked_alist(0, -1);
+
+  return closure;
+}
+
+/* FIXME: Prehaps this function should return a suitable exit code? */
+void reaper_run(struct reaper *r, struct io_backend *b)
+{
+  struct sigaction pipe;
+  struct sigaction chld;
+
+  pipe.sa_handler = SIG_IGN;
+  sigemptyset(&pipe.sa_mask);
+  pipe.sa_flags = 0;
+  pipe.sa_restorer = NULL;
+
+  chld.sa_handler = child_handler;
+  sigemptyset(&chld.sa_mask);
+  chld.sa_flags = SA_NOCLDSTOP;
+  chld.sa_restorer = NULL;
+  
+  if (sigaction(SIGPIPE, &pipe, NULL) < 0)
+    fatal("Failed to ignore SIGPIPE.\n");
+  if (sigaction(SIGCHLD, &chld, NULL) < 0)
+    fatal("Failed to install handler for SIGCHLD.\n");
+
+  halloween = 0;
+  while(io_iter(b))
+    if (halloween)
+      reap(r);
+}

src/reaper.h

+/* reaper.h
+ *
+ * Handle child processes.
+ *
+ * $Id$
+ */
+
+/* lsh, an implementation of the ssh protocol
+ *
+ * Copyright (C) 1998 Niels Möller
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#ifndef LSH_REAPER_H_INCLUDED
+#define LSH_REAPER_H_INCLUDED
+
+#include "io.h"
+
+struct exit_callback
+{
+  struct lsh_object header;
+
+  void (*exit)(struct exit_callback *closure,
+	       int signaled, int core, int value);
+};
+
+#define EXIT_CALLBACK(e, s, c, v) ((e)->exit((e), (s), (c), (v)))
+
+struct reap
+{
+  struct lsh_object header;
+
+  void (*reap)(struct reap *closure, pid_t pid, struct exit_callback *callback);
+};
+
+#define REAP(r, p, c) ((r)->reap((r), (p), (c)))
+
+struct reaper *make_reaper(void);
+void reaper_run(struct reaper *r, struct io_backend *b);
+
+#endif /* LSH_REAPER_H_INCLUDED */