(Needs a fresh dhcrelay.c)
Using rdaemon(), we can delay going in the background 'til very late,
that is after the chroot. Thanks to this we can catch errors like
a missing _dhcp user or /var/empty directory, by returning a proper exit
status. (Also, thanks to the log_perror approach in dhcrelay, those
errors also go to syslog, where the admin can easily find them after
boot.)
This is similar to what has already applied in usr.sbin/tftpd.
ok?
Index: dhcrelay.c
===================================================================
RCS file: /cvs/src/usr.sbin/dhcrelay/dhcrelay.c,v
retrieving revision 1.41
diff -u -p -p -u -r1.41 dhcrelay.c
--- dhcrelay.c 4 Sep 2016 10:43:52 -0000 1.41
+++ dhcrelay.c 4 Sep 2016 12:23:46 -0000
@@ -48,6 +48,7 @@
#include <net/if.h>
#include <errno.h>
+#include <fcntl.h>
#include <netdb.h>
#include <paths.h>
#include <pwd.h>
@@ -62,6 +63,7 @@
#include "dhcpd.h"
void usage(void);
+int rdaemon(int);
void relay(struct interface_info *, struct dhcp_packet *, int,
unsigned int, struct iaddr, struct hardware *);
char *print_hw_addr(int, int, unsigned char *);
@@ -91,7 +93,7 @@ struct server_list {
int
main(int argc, char *argv[])
{
- int ch, daemonize, opt, rdomain;
+ int ch, devnull = -1, daemonize, opt, rdomain;
extern char *__progname;
struct server_list *sp = NULL;
struct passwd *pw;
@@ -158,8 +160,11 @@ main(int argc, char *argv[])
argv++;
}
- if (daemonize)
- log_perror = 0;
+ if (daemonize) {
+ devnull = open(_PATH_DEVNULL, O_RDWR, 0);
+ if (devnull == -1)
+ error("open(%s): %m", _PATH_DEVNULL);
+ }
if (interfaces == NULL)
error("no interface given");
@@ -230,8 +235,6 @@ main(int argc, char *argv[])
time(&cur_time);
bootp_packet_handler = relay;
- if (daemonize)
- daemon(0, 0);
if ((pw = getpwnam("_dhcp")) == NULL)
error("user \"_dhcp\" not found");
@@ -244,6 +247,12 @@ main(int argc, char *argv[])
setresuid(pw->pw_uid, pw->pw_uid, pw->pw_uid))
error("can't drop privileges: %m");
+ if (daemonize) {
+ if (rdaemon(devnull) == -1)
+ error("rdaemon: %m");
+ log_perror = 0;
+ }
+
dispatch();
/* not reached */
@@ -354,6 +363,31 @@ usage(void)
fprintf(stderr, "usage: %s [-do] -i interface server1 [... serverN]\n",
__progname);
exit(1);
+}
+
+int
+rdaemon(int devnull)
+{
+
+ switch (fork()) {
+ case -1:
+ return (-1);
+ case 0:
+ break;
+ default:
+ _exit(0);
+ }
+
+ if (setsid() == -1)
+ return (-1);
+
+ (void)dup2(devnull, STDIN_FILENO);
+ (void)dup2(devnull, STDOUT_FILENO);
+ (void)dup2(devnull, STDERR_FILENO);
+ if (devnull > 2)
+ (void)close(devnull);
+
+ return (0);
}
char *
--
jca | PGP : 0x1524E7EE / 5135 92C1 AD36 5293 2BDF DDCC 0DFA 74AE 1524 E7EE
