statefiles: remove hosts entries from statefile

Further simplify statefiles.c by removing the hosts entries from the
statefile (they can be found in the dedicated hosts files instead).

Signed-off-by: David Härdeman <david@hardeman.nu>
Link: https://github.com/openwrt/odhcpd/pull/331
Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>

5 files changed, 42 insertions, 52 deletions

diff --git a/README.md b/README.md
index 3907089..c375450 100644
--- a/README.md
+++ b/README.md
@@ -62,9 +62,9 @@ and may also receive information from ubus
 | Option	| Type	|Default| Description |
 | :------------ | :---- | :----	| :---------- |
 | maindhcp	| bool	| 0	| Use odhcpd as the main DHCPv4 service |
-| leasefile	| string|	| DHCP/v6 lease/hostfile |
+| leasefile	| string|	| DHCPv4/6 lease file |
 | leasetrigger	| string|	| Lease trigger script |
-| hostsdir	| string|	| DHCP/v6 hostfile directory (one file per interface will be created) |
+| hostsdir	| string|	| DHCPv4/v6 hostfile directory (one file per interface will be created) |
 | loglevel	|integer| 6	| Syslog level priority (0-7) |
 | piofolder	|string |	| Folder to store IPv6 prefix information (to detect stale prefixes, see RFC9096, §3.5) |
 | enable_tz |bool | 1 | Toggle whether RFC4833 timezone information is sent to clients, if set in system  |
diff --git a/src/dhcpv6-ia.c b/src/dhcpv6-ia.c
index ca3f89d..34b088b 100644
--- a/src/dhcpv6-ia.c
+++ b/src/dhcpv6-ia.c
@@ -820,7 +820,7 @@ struct log_ctxt {
 	int buf_idx;
 };
 
-static void dhcpv6_log_ia_addr(_o_unused struct dhcpv6_lease *lease, struct in6_addr *addr, int prefix,
+static void dhcpv6_log_ia_addr(_o_unused struct dhcpv6_lease *lease, struct in6_addr *addr, uint8_t prefix_len,
 			       _o_unused uint32_t pref_lt, _o_unused uint32_t valid_lt, void *arg)
 {
 	struct log_ctxt *ctxt = (struct log_ctxt *)arg;
@@ -828,7 +828,7 @@ static void dhcpv6_log_ia_addr(_o_unused struct dhcpv6_lease *lease, struct in6_
 
 	inet_ntop(AF_INET6, addr, addrbuf, sizeof(addrbuf));
 	ctxt->buf_idx += snprintf(ctxt->buf + ctxt->buf_idx, ctxt->buf_len - ctxt->buf_idx,
-					"%s/%d ", addrbuf, prefix);
+				  " %s/%" PRIu8, addrbuf, prefix_len);
 }
 
 static void dhcpv6_log(uint8_t msgtype, struct interface *iface, time_t now,
@@ -889,7 +889,7 @@ static void dhcpv6_log(uint8_t msgtype, struct interface *iface, time_t now,
 		odhcpd_enum_addr6(iface, a, now, dhcpv6_log_ia_addr, &ctxt);
 	}
 
-	info("DHCPV6 %s %s from %s on %s: %s %s", type, (is_pd) ? "IA_PD" : "IA_NA",
+	info("DHCPV6 %s %s from %s on %s: %s%s", type, (is_pd) ? "IA_PD" : "IA_NA",
 	     duidbuf, iface->name, status, leasebuf);
 }
 
diff --git a/src/odhcpd.h b/src/odhcpd.h
index 8a6461c..6265c94 100644
--- a/src/odhcpd.h
+++ b/src/odhcpd.h
@@ -559,7 +559,7 @@ int odhcpd_bmemcmp(const void *av, const void *bv, size_t bits);
 void odhcpd_bmemcpy(void *av, const void *bv, size_t bits);
 
 typedef void (*odhcpd_enum_addr6_cb_t)(struct dhcpv6_lease *lease,
-				       struct in6_addr *addr, int prefix,
+				       struct in6_addr *addr, uint8_t prefix_len,
 				       uint32_t pref, uint32_t valid,
 				       void *arg);
 void odhcpd_enum_addr6(struct interface *iface, struct dhcpv6_lease *lease,
diff --git a/src/statefiles.c b/src/statefiles.c
index 8862f1b..0c82a6d 100644
--- a/src/statefiles.c
+++ b/src/statefiles.c
@@ -21,6 +21,7 @@
 #include <arpa/nameser.h>
 #include <arpa/inet.h>
 #include <resolv.h>
+#include <spawn.h>
 
 #include <libubox/md5.h>
 
@@ -36,9 +37,6 @@ struct write_ctxt {
 	struct interface *iface;
 	time_t now; // CLOCK_MONOTONIC
 	time_t wall_time;
-	char *buf;
-	int buf_len;
-	int buf_idx;
 };
 
 static void statefiles_write_host(const char *ipbuf, const char *hostname, struct write_ctxt *ctxt)
@@ -68,7 +66,7 @@ static bool statefiles_write_host6(struct write_ctxt *ctxt, struct dhcpv6_lease
 	return true;
 }
 
-static void statefiles_write_host6_cb(struct dhcpv6_lease *lease, struct in6_addr *addr, _o_unused int prefix,
+static void statefiles_write_host6_cb(struct dhcpv6_lease *lease, struct in6_addr *addr, _o_unused uint8_t prefix_len,
 				      _o_unused uint32_t pref_lt, _o_unused uint32_t valid_lt, void *arg)
 {
 	struct write_ctxt *ctxt = (struct write_ctxt *)arg;
@@ -161,53 +159,50 @@ err:
 	close(fd);
 }
 
-static void statefiles_write_state6_addr(struct dhcpv6_lease *lease, struct in6_addr *addr, int prefix,
+static void statefiles_write_state6_addr(struct dhcpv6_lease *lease, struct in6_addr *addr, uint8_t prefix_len,
 					 _o_unused uint32_t pref_lt, _o_unused uint32_t valid_lt, void *arg)
 {
 	struct write_ctxt *ctxt = (struct write_ctxt *)arg;
 	char ipbuf[INET6_ADDRSTRLEN];
 
-	inet_ntop(AF_INET6, addr, ipbuf, sizeof(ipbuf));
-
-	if (statefiles_write_host6(ctxt, lease, addr)) {
-		md5_hash(ipbuf, strlen(ipbuf), &ctxt->md5);
+	if (lease->hostname && !(lease->flags & OAF_BROKEN_HOSTNAME) && lease->flags & OAF_DHCPV6_NA) {
+		md5_hash(addr, sizeof(*addr), &ctxt->md5);
 		md5_hash(lease->hostname, strlen(lease->hostname), &ctxt->md5);
 	}
 
 	if (!ctxt->fp)
 		return;
 
-	ctxt->buf_idx += snprintf(ctxt->buf + ctxt->buf_idx,
-				  ctxt->buf_len - ctxt->buf_idx,
-				  " %s/%d", ipbuf, prefix);
+	inet_ntop(AF_INET6, addr, ipbuf, sizeof(ipbuf));
+	fprintf(ctxt->fp, " %s/%" PRIu8, ipbuf, prefix_len);
 }
 
 static void statefiles_write_state6(struct write_ctxt *ctxt, struct dhcpv6_lease *lease)
 {
 	char duidbuf[DUID_HEXSTRLEN];
 
-	ctxt->buf_idx = 0;
-	odhcpd_enum_addr6(ctxt->iface, lease, ctxt->now, statefiles_write_state6_addr, ctxt);
-
-	if (!ctxt->fp)
-		return;
+	if (ctxt->fp) {
+		odhcpd_hexlify(duidbuf, lease->duid, lease->duid_len);
+
+		/* # <iface> <hexduid> <hexiaid> <hostname> <valid_until> <assigned_[host|subnet]_id> <pfx_length> [<addrs> ...] */
+		fprintf(ctxt->fp,
+			"# %s %s %x %s%s %" PRId64 " %" PRIx64 " %" PRIu8,
+			ctxt->iface->ifname, duidbuf, ntohl(lease->iaid),
+			(lease->flags & OAF_BROKEN_HOSTNAME) ? "broken\\x20" : "",
+			(lease->hostname ? lease->hostname : "-"),
+			(lease->valid_until > ctxt->now ?
+			 (int64_t)(lease->valid_until - ctxt->now + ctxt->wall_time) :
+			 (INFINITE_VALID(lease->valid_until) ? -1 : 0)),
+			(lease->flags & OAF_DHCPV6_NA ?
+			 lease->assigned_host_id :
+			 (uint64_t)lease->assigned_subnet_id),
+			lease->length);
+	}
 
-	odhcpd_hexlify(duidbuf, lease->duid, lease->duid_len);
+	odhcpd_enum_addr6(ctxt->iface, lease, ctxt->now, statefiles_write_state6_addr, ctxt);
 
-	/* # <iface> <hexduid> <hexiaid> <hostname> <valid_until> <assigned_[host|subnet]_id> <pfx_length> [<addrs> ...] */
-	fprintf(ctxt->fp,
-		"# %s %s %x %s%s %" PRId64 " %" PRIx64 " %" PRIu8 "%s\n",
-		ctxt->iface->ifname, duidbuf, ntohl(lease->iaid),
-		(lease->flags & OAF_BROKEN_HOSTNAME) ? "broken\\x20" : "",
-		(lease->hostname ? lease->hostname : "-"),
-		(lease->valid_until > ctxt->now ?
-		 (int64_t)(lease->valid_until - ctxt->now + ctxt->wall_time) :
-		 (INFINITE_VALID(lease->valid_until) ? -1 : 0)),
-		(lease->flags & OAF_DHCPV6_NA ?
-		 lease->assigned_host_id :
-		 (uint64_t)lease->assigned_subnet_id),
-		lease->length,
-		ctxt->buf);
+	if (ctxt->fp)
+		putc('\n', ctxt->fp);
 }
 
 static void statefiles_write_state4(struct write_ctxt *ctxt, struct dhcpv4_lease *lease)
@@ -215,16 +210,15 @@ static void statefiles_write_state4(struct write_ctxt *ctxt, struct dhcpv4_lease
 	char hexhwaddr[sizeof(lease->hwaddr) * 2 + 1];
 	char ipbuf[INET6_ADDRSTRLEN];
 
-	inet_ntop(AF_INET, &lease->ipv4, ipbuf, sizeof(ipbuf));
-
-	if (statefiles_write_host4(ctxt, lease)) {
-		md5_hash(ipbuf, strlen(ipbuf), &ctxt->md5);
+	if (lease->hostname && !(lease->flags & OAF_BROKEN_HOSTNAME)) {
+		md5_hash(&lease->ipv4, sizeof(lease->ipv4), &ctxt->md5);
 		md5_hash(lease->hostname, strlen(lease->hostname), &ctxt->md5);
 	}
 
 	if (!ctxt->fp)
 		return;
 
+	inet_ntop(AF_INET, &lease->ipv4, ipbuf, sizeof(ipbuf));
 	odhcpd_hexlify(hexhwaddr, lease->hwaddr, sizeof(lease->hwaddr));
 
 	/* # <iface> <hexhwaddr> "ipv4" <hostname> <valid_until> <hexaddr> "32" <addrstr>"/32" */
@@ -242,11 +236,8 @@ static void statefiles_write_state4(struct write_ctxt *ctxt, struct dhcpv4_lease
 /* Returns true if there are changes to be written to the hosts file(s) */
 static bool statefiles_write_state(time_t now)
 {
-	char leasebuf[512];
 	struct write_ctxt ctxt = {
 		.fp = NULL,
-		.buf = leasebuf,
-		.buf_len = sizeof(leasebuf),
 		.now = now,
 		.wall_time = time(NULL),
 	};
@@ -338,10 +329,9 @@ bool statefiles_write()
 
 	if (config.dhcp_cb) {
 		char *argv[2] = { config.dhcp_cb, NULL };
-		if (!vfork()) {
-			execv(argv[0], argv);
-			_exit(128);
-		}
+		pid_t pid;
+
+		posix_spawn(&pid, argv[0], NULL, NULL, argv, environ);
 	}
 
 	return true;
diff --git a/src/ubus.c b/src/ubus.c
index 5b6cf22..2f2f206 100644
--- a/src/ubus.c
+++ b/src/ubus.c
@@ -90,7 +90,7 @@ static int handle_dhcpv4_leases(struct ubus_context *ctx, _o_unused struct ubus_
 }
 #endif /* DHCPV4_SUPPORT */
 
-static void dhcpv6_blobmsg_ia_addr(_o_unused struct dhcpv6_lease *lease, struct in6_addr *addr, int prefix,
+static void dhcpv6_blobmsg_ia_addr(_o_unused struct dhcpv6_lease *lease, struct in6_addr *addr, uint8_t prefix_len,
 				   uint32_t pref_lt, uint32_t valid_lt, _o_unused void *arg)
 {
 	void *a	= blobmsg_open_table(&b, NULL);
@@ -103,8 +103,8 @@ static void dhcpv6_blobmsg_ia_addr(_o_unused struct dhcpv6_lease *lease, struct
 	blobmsg_add_u32(&b, "valid-lifetime",
 			valid_lt == UINT32_MAX ? (uint32_t)-1 : valid_lt);
 
-	if (prefix != 128)
-		blobmsg_add_u32(&b, "prefix-length", prefix);
+	if (prefix_len != 128)
+		blobmsg_add_u32(&b, "prefix-length", prefix_len);
 
 	blobmsg_close_table(&b, a);
 }