diff options
| author |   jca <jca@openbsd.org> | 2016-09-15 16:16:03 +0000 |
|---|---|---|
| committer | jca <jca@openbsd.org> | 2016-09-15 16:16:03 +0000 |
| commit | 7307f9fa4f162d2d204b1d0d4d979c6abfd62006 (patch) | |
| tree | 7cdd0649f97982a6a1a1227061f87392dc84c1e8 /usr.sbin/dhcrelay | |
| parent | Add Hyper-V devices (diff) | |
| download | wireguard-openbsd-7307f9fa4f162d2d204b1d0d4d979c6abfd62006.tar.xz wireguard-openbsd-7307f9fa4f162d2d204b1d0d4d979c6abfd62006.zip | |
Go in the background later, using rdaemon().
rdaemon() works like daemon(3) but requires its caller to pre-open
/dev/null. This makes it possible to go in the background after
a chroot(2), allowing for more error checking. The pattern is basically
- open /dev/null
- chroot
- privdrop
- rdaemon
"design" initialy discussed with semarie@ a while ago, ok dlg@
Diffstat (limited to 'usr.sbin/dhcrelay')
| -rw-r--r-- | usr.sbin/dhcrelay/dhcrelay.c | 46 |
1 files changed, 40 insertions, 6 deletions
diff --git a/usr.sbin/dhcrelay/dhcrelay.c b/usr.sbin/dhcrelay/dhcrelay.c index 88b1afda29d..54ee05a6fc3 100644 --- a/usr.sbin/dhcrelay/dhcrelay.c +++ b/usr.sbin/dhcrelay/dhcrelay.c @@ -1,4 +1,4 @@ -/* $OpenBSD: dhcrelay.c,v 1.41 2016/09/04 10:43:52 jca Exp $ */ +/* $OpenBSD: dhcrelay.c,v 1.42 2016/09/15 16:16:03 jca Exp $ */ /* * Copyright (c) 2004 Henning Brauer <henning@cvs.openbsd.org> @@ -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 */ @@ -356,6 +365,31 @@ usage(void) 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 * print_hw_addr(int htype, int hlen, unsigned char *data) { |