save some file descriptors. instead of a pipe, use kevent to watch parent

diff --git a/usr.sbin/rebound/rebound.c b/usr.sbin/rebound/rebound.c
index 2c30a28..740cbe7 100644 (file)
--- a/usr.sbin/rebound/rebound.c
+++ b/usr.sbin/rebound/rebound.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: rebound.c,v 1.24 2015/10/16 20:12:06 tedu Exp $ */
+/* $OpenBSD: rebound.c,v 1.25 2015/10/16 20:25:09 tedu Exp $ */
 /*
  * Copyright (c) 2015 Ted Unangst <tedu@openbsd.org>
  *
@@ -356,7 +356,7 @@ readconfig(FILE *conf, struct sockaddr_storage *remoteaddr)
 }
 
 static int
-launch(const char *confname, int ud, int ld, int kq, int *pfd)
+launch(const char *confname, int ud, int ld, int kq)
 {
        struct sockaddr_storage remoteaddr;
        struct kevent chlist[2], kev[4];
@@ -366,7 +366,7 @@ launch(const char *confname, int ud, int ld, int kq, int *pfd)
        struct passwd *pwd;
        FILE *conf;
        int i, r, af;
-       pid_t child;
+       pid_t parent, child;
 
        conf = fopen(confname, "r");
        if (!conf) {
@@ -374,12 +374,15 @@ launch(const char *confname, int ud, int ld, int kq, int *pfd)
                return -1;
        }
 
+       parent = getpid();
        if (!debug) {
                if ((child = fork()))
                        return child;
-               close(pfd[1]);
        }
 
+       close(kq);
+       kq = kqueue();
+
        if (!(pwd = getpwnam("_rebound")))
                logerr("getpwnam failed");
 
@@ -387,13 +390,13 @@ launch(const char *confname, int ud, int ld, int kq, int *pfd)
                logerr("chroot failed (%d)", errno);
 
        setproctitle("worker");
+       EV_SET(&kev[0], parent, EVFILT_PROC, EV_ADD, NOTE_EXIT, 0, NULL);
+       kevent(kq, kev, 1, NULL, 0, NULL);
        if (setgroups(1, &pwd->pw_gid) ||
            setresgid(pwd->pw_gid, pwd->pw_gid, pwd->pw_gid) ||
            setresuid(pwd->pw_uid, pwd->pw_uid, pwd->pw_uid))
                logerr("failed to privdrop");
 
-       close(kq);
-
        if (pledge("stdio inet", NULL) == -1)
                logerr("pledge failed");
 
@@ -402,13 +405,10 @@ launch(const char *confname, int ud, int ld, int kq, int *pfd)
        if (af == -1)
                logerr("failed to read config %s", confname);
 
-       kq = kqueue();
-
        EV_SET(&kev[0], ud, EVFILT_READ, EV_ADD, 0, 0, NULL);
        EV_SET(&kev[1], ld, EVFILT_READ, EV_ADD, 0, 0, NULL);
        EV_SET(&kev[2], SIGHUP, EVFILT_SIGNAL, EV_ADD, 0, 0, NULL);
-       EV_SET(&kev[3], pfd[0], EVFILT_READ, EV_ADD, 0, 0, NULL);
-       kevent(kq, kev, 4, NULL, 0, NULL);
+       kevent(kq, kev, 3, NULL, 0, NULL);
        signal(SIGHUP, SIG_IGN);
        logmsg(LOG_INFO, "worker process going to work");
        while (1) {
@@ -422,11 +422,9 @@ launch(const char *confname, int ud, int ld, int kq, int *pfd)
                        if (kev[i].filter == EVFILT_SIGNAL) {
                                logmsg(LOG_INFO, "hupped, exiting");
                                exit(0);
-                       } else if (kev[i].ident == pfd[0]) {
-                               if (kev[i].flags & EV_EOF) {
-                                       logmsg(LOG_INFO, "parent died");
-                                       exit(0);
-                               }
+                       } else if (kev[i].filter == EVFILT_PROC) {
+                               logmsg(LOG_INFO, "parent died");
+                               exit(0);
                        } else if (kev[i].ident == ud) {
                                req = newrequest(ud,
                                    (struct sockaddr *)&remoteaddr);
@@ -522,7 +520,6 @@ main(int argc, char **argv)
        struct sockaddr_in bindaddr;
        int r, kq, ld, ud, ch;
        int one;
-       int pfd[2];
        int childdead, hupped;
        pid_t child;
        struct kevent kev;
@@ -578,10 +575,8 @@ main(int argc, char **argv)
        if (listen(ld, 10) == -1)
                err(1, "listen");
 
-       pipe(pfd);
-
        if (debug) {
-               launch(conffile, ud, ld, -1, pfd);
+               launch(conffile, ud, ld, -1);
                return 1;
        }
 
@@ -593,7 +588,7 @@ main(int argc, char **argv)
        while (1) {
                hupped = 0;
                childdead = 0;
-               child = launch(conffile, ud, ld, kq, pfd);
+               child = launch(conffile, ud, ld, kq);
                if (child == -1)
                        logerr("failed to launch");