Ted Unangst wrote:
> Bob Beck wrote:
> > how is rebound going to handle a change in resolv.conf? thats still a
> > problem here
>
> oh, that's easy. it watches the file for changes. i never quite got around to
> that, but it's another five lines.
ok, so it's a net +15 lines, including blanks.
Index: rebound.8
===================================================================
RCS file: /cvs/src/usr.sbin/rebound/rebound.8,v
retrieving revision 1.4
diff -u -p -r1.4 rebound.8
--- rebound.8 4 Dec 2015 04:50:43 -0000 1.4
+++ rebound.8 15 Sep 2016 00:57:21 -0000
@@ -33,9 +33,7 @@ The options are as follows:
.Bl -tag -width Ds
.It Fl c Ar config
Specify an alternative configuration file, instead of the default
-.Pa /etc/rebound.conf .
-At present, the config file consists of a single line containing the next
-hop DNS server.
+.Pa /etc/resolv.conf .
.Nm
will reload the configuration file when sent a SIGHUP signal.
.It Fl d
@@ -46,8 +44,8 @@ does not
into the background.
.El
.Sh FILES
-.Bl -tag -width "/etc/rebound.confXX" -compact
-.It Pa /etc/rebound.conf
+.Bl -tag -width "/etc/resolv.confXX" -compact
+.It Pa /etc/resolv.conf
Default
.Nm
configuration file.
Index: rebound.c
===================================================================
RCS file: /cvs/src/usr.sbin/rebound/rebound.c,v
retrieving revision 1.70
diff -u -p -r1.70 rebound.c
--- rebound.c 1 Sep 2016 10:57:24 -0000 1.70
+++ rebound.c 15 Sep 2016 02:30:46 -0000
@@ -33,10 +33,12 @@
#include <string.h>
#include <err.h>
#include <unistd.h>
+#include <fcntl.h>
#include <pwd.h>
#include <errno.h>
#include <getopt.h>
#include <stdarg.h>
+#include <ctype.h>
#define MINIMUM(a,b) (((a)<(b))?(a):(b))
@@ -455,34 +457,51 @@ fail:
}
static int
-readconfig(FILE *conf, union sockun *remoteaddr)
+readconfig(int conffd, union sockun *remoteaddr)
{
+ const char ns[] = "nameserver";
char buf[1024];
+ char *p;
struct sockaddr_in *sin = &remoteaddr->i;
struct sockaddr_in6 *sin6 = &remoteaddr->i6;
+ FILE *conf;
+ int rv = -1;
- if (fgets(buf, sizeof(buf), conf) == NULL)
- return -1;
- buf[strcspn(buf, "\n")] = '\0';
+ conf = fdopen(conffd, "r");
- memset(remoteaddr, 0, sizeof(*remoteaddr));
- if (inet_pton(AF_INET, buf, &sin->sin_addr) == 1) {
- sin->sin_len = sizeof(*sin);
- sin->sin_family = AF_INET;
- sin->sin_port = htons(53);
- return AF_INET;
- } else if (inet_pton(AF_INET6, buf, &sin6->sin6_addr) == 1) {
- sin6->sin6_len = sizeof(*sin6);
- sin6->sin6_family = AF_INET6;
- sin6->sin6_port = htons(53);
- return AF_INET6;
- } else {
- return -1;
+ while (fgets(buf, sizeof(buf), conf) != NULL) {
+ buf[strcspn(buf, "\n")] = '\0';
+
+ if (strncmp(buf, ns, strlen(ns)) != 0)
+ continue;
+ p = buf + strlen(ns) + 1;
+ while (isspace((unsigned char)*p))
+ p++;
+
+ /* this will not end well */
+ if (strcmp(p, "127.0.0.1") == 0)
+ continue;
+
+ memset(remoteaddr, 0, sizeof(*remoteaddr));
+ if (inet_pton(AF_INET, p, &sin->sin_addr) == 1) {
+ sin->sin_len = sizeof(*sin);
+ sin->sin_family = AF_INET;
+ sin->sin_port = htons(53);
+ rv = AF_INET;
+ } else if (inet_pton(AF_INET6, p, &sin6->sin6_addr) == 1) {
+ sin6->sin6_len = sizeof(*sin6);
+ sin6->sin6_family = AF_INET6;
+ sin6->sin6_port = htons(53);
+ rv = AF_INET6;
+ }
+ break;
}
+ fclose(conf);
+ return rv;
}
static int
-launch(FILE *conf, int ud, int ld, int kq)
+launch(int conffd, int ud, int ld)
{
union sockun remoteaddr;
struct kevent ch[2], kev[4];
@@ -490,16 +509,13 @@ launch(FILE *conf, int ud, int ld, int k
struct request *req;
struct dnscache *ent;
struct passwd *pwd;
- int i, r, af;
+ int i, r, af, kq;
pid_t parent, child;
parent = getpid();
if (!debug) {
- if ((child = fork())) {
- fclose(conf);
+ if ((child = fork()))
return child;
- }
- close(kq);
}
kq = kqueue();
@@ -526,8 +542,7 @@ launch(FILE *conf, int ud, int ld, int k
if (pledge("stdio inet", NULL) == -1)
logerr("pledge failed");
- af = readconfig(conf, &remoteaddr);
- fclose(conf);
+ af = readconfig(conffd, &remoteaddr);
if (af == -1)
logerr("parse error in config file");
@@ -647,6 +662,23 @@ launch(FILE *conf, int ud, int ld, int k
exit(1);
}
+static int
+openconfig(const char *confname, int kq)
+{
+ struct kevent kev;
+ int conffd;
+
+ conffd = open(confname, O_RDONLY);
+ if (conffd == -1)
+ logerr("failed to open config %s", confname);
+ if (kq != -1) {
+ EV_SET(&kev, conffd, EVFILT_VNODE, EV_ADD,
+ NOTE_DELETE | NOTE_WRITE | NOTE_ATTRIB, 0, NULL);
+ kevent(kq, &kev, 1, NULL, 0, NULL);
+ }
+ return conffd;
+}
+
static void __dead
usage(void)
{
@@ -658,15 +690,14 @@ int
main(int argc, char **argv)
{
union sockun bindaddr;
- int r, kq, ld, ud, ch;
+ int r, kq, ld, ud, ch, conffd;
int one;
int childdead, hupped;
pid_t child;
struct kevent kev;
struct rlimit rlim;
struct timespec ts, *timeout = NULL;
- const char *confname = "/etc/rebound.conf";
- FILE *conf;
+ const char *confname = "/etc/resolv.conf";
while ((ch = getopt(argc, argv, "c:d")) != -1) {
switch (ch) {
@@ -726,17 +757,15 @@ main(int argc, char **argv)
logerr("bind: %s", strerror(errno));
if (listen(ld, 10) == -1)
logerr("listen: %s", strerror(errno));
-
- conf = fopen(confname, "r");
- if (!conf)
- logerr("failed to open config %s", confname);
-
+
signal(SIGPIPE, SIG_IGN);
signal(SIGUSR1, SIG_IGN);
signal(SIGHUP, SIG_IGN);
- if (debug)
- return launch(conf, ud, ld, -1);
+ if (debug) {
+ conffd = openconfig(confname, -1);
+ return launch(conffd, ud, ld);
+ }
if (daemon(0, 0) == -1)
logerr("daemon: %s", strerror(errno));
@@ -744,12 +773,14 @@ main(int argc, char **argv)
kq = kqueue();
+ conffd = openconfig(confname, kq);
+
EV_SET(&kev, SIGHUP, EVFILT_SIGNAL, EV_ADD, 0, 0, NULL);
kevent(kq, &kev, 1, NULL, 0, NULL);
while (1) {
hupped = 0;
childdead = 0;
- child = launch(conf, ud, ld, kq);
+ child = launch(conffd, ud, ld);
if (child == -1)
logerr("failed to launch");
@@ -767,6 +798,12 @@ main(int argc, char **argv)
if (r == 0) {
/* timeout expired */
logerr("child died without HUP");
+ } else if (kev.filter == EVFILT_VNODE) {
+ /* config file changed */
+ logmsg(LOG_INFO, "config changed, reloading");
+ close(conffd);
+ sleep(1);
+ raise(SIGHUP);
} else if (kev.filter == EVFILT_SIGNAL) {
/* signaled. kill child. */
logmsg(LOG_INFO, "received HUP, restarting");
@@ -774,10 +811,7 @@ main(int argc, char **argv)
if (childdead)
break;
kill(child, SIGHUP);
- conf = fopen(confname, "r");
- if (!conf)
- logerr("failed to open config %s",
- confname);
+ conffd = openconfig(confname, kq);
} else if (kev.filter == EVFILT_PROC) {
/* child died. wait for our own HUP. */
logmsg(LOG_INFO, "observed child exit");
