Re: prevent bgpd from starting when control socket already used

[Remi Locherer]

Hi,

from the discussion I understand nobody rejects the functionality.

To ease the review here again the diff (with incorporated feedback from
anton@ (redundant parens)).

Any comments or OKs?

Remi


cvs diff: Diffing .
Index: bgpd.c
===================================================================
RCS file: /cvs/src/usr.sbin/bgpd/bgpd.c,v
retrieving revision 1.204
diff -u -p -r1.204 bgpd.c
--- bgpd.c      29 Sep 2018 08:11:11 -0000      1.204
+++ bgpd.c      18 Nov 2018 22:21:51 -0000
@@ -939,6 +939,8 @@ control_setup(struct bgpd_config *conf)
                }
                if ((cname = strdup(conf->csock)) == NULL)
                        fatal("strdup");
+               if (control_check(cname) == -1)
+                       fatalx("control socket check failed");
                if ((fd = control_init(0, cname)) == -1)
                        fatalx("control socket setup failed");
                if (control_listen(fd) == -1)
Index: control.c
===================================================================
RCS file: /cvs/src/usr.sbin/bgpd/control.c,v
retrieving revision 1.90
diff -u -p -r1.90 control.c
--- control.c   11 Aug 2017 16:02:53 -0000      1.90
+++ control.c   10 Nov 2018 20:52:46 -0000
@@ -38,6 +38,32 @@ void          control_result(struct ctl_conn *,
 ssize_t                 imsg_read_nofd(struct imsgbuf *);
 
 int
+control_check(char *path)
+{
+       struct sockaddr_un       sun;
+       int                      fd;
+
+       bzero(&sun, sizeof(sun));
+       sun.sun_family = AF_UNIX;
+       strlcpy(sun.sun_path, path, sizeof(sun.sun_path));
+
+       if ((fd = socket(AF_UNIX, SOCK_STREAM, 0)) == -1) {
+               log_warn("control_check: socket check");
+               return (-1);
+       }
+
+       if (connect(fd, (struct sockaddr *)&sun, sizeof(sun)) == 0) {
+               log_warnx("control_check: socket in use");
+               close(fd);
+               return (-1);
+       }
+
+       close(fd);
+
+       return (0);
+}
+
+int
 control_init(int restricted, char *path)
 {
        struct sockaddr_un       sun;
Index: session.h
===================================================================
RCS file: /cvs/src/usr.sbin/bgpd/session.h,v
retrieving revision 1.125
diff -u -p -r1.125 session.h
--- session.h   24 Oct 2018 08:26:37 -0000      1.125
+++ session.h   10 Nov 2018 21:53:04 -0000
@@ -250,6 +250,7 @@ void         prepare_listeners(struct bgpd_conf
 int     get_mpe_label(struct rdomain *);
 
 /* control.c */
+int    control_check(char *);
 int    control_init(int, char *);
 int    control_listen(int);
 void   control_shutdown(int);