From: David Härdeman <david@hardeman.nu>
Date: Sat, 8 Nov 2025 17:33:07 +0000 (+0100)
Subject: statefiles: don't make hostsfile dependent on statefile
X-Git-Url: http://git.openwrt.org/?a=commitdiff_plain;h=9ba4e3e0f5c5b431fa54e413b4316f3f808700cf;p=project%2Fodhcpd.git

statefiles: don't make hostsfile dependent on statefile

Right now, the hosts file will only be created if the statefile is also
configured (and that fact isn't documented in the README.md, only in
commit logs (see 4bbc6e74248feeb756bd03dc500fb4f446ccfc49).

With this patch, the hostsfile is generated whether the statefile is
configured or not.

Signed-off-by: David Härdeman <david@hardeman.nu>
Link: https://github.com/openwrt/odhcpd/pull/302
Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
---

diff --git a/src/statefiles.c b/src/statefiles.c
index a2d39af..b362a1a 100644
--- a/src/statefiles.c
+++ b/src/statefiles.c
@@ -60,8 +60,11 @@ static bool statefiles_write_host6(struct write_ctxt *ctxt, struct dhcpv6_lease
 	if (!lease->hostname || lease->flags & OAF_BROKEN_HOSTNAME || !(lease->flags & OAF_DHCPV6_NA))
 		return false;
 
-	inet_ntop(AF_INET6, addr, ipbuf, sizeof(ipbuf));
-	statefiles_write_host(ipbuf, lease->hostname, ctxt);
+	if (!ctxt->fp) {
+		inet_ntop(AF_INET6, addr, ipbuf, sizeof(ipbuf));
+		statefiles_write_host(ipbuf, lease->hostname, ctxt);
+	}
+
 	return true;
 }
 
@@ -81,8 +84,11 @@ static bool statefiles_write_host4(struct write_ctxt *ctxt, struct dhcpv4_lease
 	if (!lease->hostname || lease->flags & OAF_BROKEN_HOSTNAME)
 		return false;
 
-	inet_ntop(AF_INET, &addr, ipbuf, sizeof(ipbuf));
-	statefiles_write_host(ipbuf, lease->hostname, ctxt);
+	if (!ctxt->fp) {
+		inet_ntop(AF_INET, &addr, ipbuf, sizeof(ipbuf));
+		statefiles_write_host(ipbuf, lease->hostname, ctxt);
+	}
+
 	return true;
 }
 
@@ -168,6 +174,9 @@ static void statefiles_write_state6_addr(struct dhcpv6_lease *lease, struct in6_
 		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);
@@ -180,6 +189,9 @@ static void statefiles_write_state6(struct write_ctxt *ctxt, struct dhcpv6_lease
 	ctxt->buf_idx = 0;
 	odhcpd_enum_addr6(ctxt->iface, lease, ctxt->now, statefiles_write_state6_addr, ctxt);
 
+	if (!ctxt->fp)
+		return;
+
 	odhcpd_hexlify(duidbuf, lease->clid_data, lease->clid_len);
 
 	/* # <iface> <hexduid> <hexiaid> <hostname> <valid_until> <assigned_[host|subnet]_id> <pfx_length> [<addrs> ...] */
@@ -211,6 +223,9 @@ static void statefiles_write_state4(struct write_ctxt *ctxt, struct dhcpv4_lease
 		md5_hash(lease->hostname, strlen(lease->hostname), &ctxt->md5);
 	}
 
+	if (!ctxt->fp)
+		return;
+
 	odhcpd_hexlify(hexhwaddr, lease->hwaddr, sizeof(lease->hwaddr));
 
 	/* # <iface> <hexhwaddr> "ipv4" <hostname> <valid_until> <hexaddr> "32" <addrstr>"/32" */
@@ -225,6 +240,7 @@ static void statefiles_write_state4(struct write_ctxt *ctxt, struct dhcpv4_lease
 		ntohl(lease->addr), ipbuf);
 }
 
+/* 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];
@@ -235,31 +251,30 @@ static bool statefiles_write_state(time_t now)
 		.now = now,
 		.wall_time = time(NULL),
 	};
-	size_t tmp_statefile_strlen;
-	char *tmp_statefile;
+	char *tmp_statefile = NULL;
 	uint8_t newmd5[16];
 	int fd;
 
-	if (config.dhcp_statedir_fd < 0 || !config.dhcp_statefile)
-		return false;
+	if (config.dhcp_statedir_fd >= 0 && config.dhcp_statefile) {
+		size_t tmp_statefile_strlen = strlen(config.dhcp_statefile) + 2;
 
-	tmp_statefile_strlen = strlen(config.dhcp_statefile) + 2;
-	tmp_statefile = alloca(tmp_statefile_strlen);
-	sprintf(tmp_statefile, ".%s", config.dhcp_statefile);
+		tmp_statefile = alloca(tmp_statefile_strlen);
+		sprintf(tmp_statefile, ".%s", config.dhcp_statefile);
 
-	fd = openat(config.dhcp_statedir_fd, tmp_statefile, O_CREAT | O_WRONLY | O_CLOEXEC, 0644);
-	if (fd < 0)
-		goto err;
+		fd = openat(config.dhcp_statedir_fd, tmp_statefile, O_CREAT | O_WRONLY | O_CLOEXEC, 0644);
+		if (fd < 0)
+			goto err;
 
-	if (lockf(fd, F_LOCK, 0) < 0)
-		goto err;
+		if (lockf(fd, F_LOCK, 0) < 0)
+			goto err;
 
-	if (ftruncate(fd, 0) < 0)
-		goto err;
+		if (ftruncate(fd, 0) < 0)
+			goto err;
 
-	ctxt.fp = fdopen(fd, "w");
-	if (!ctxt.fp)
-		goto err;
+		ctxt.fp = fdopen(fd, "w");
+		if (!ctxt.fp)
+			goto err;
+	}
 
 	md5_begin(&ctxt.md5);
 
@@ -293,17 +308,18 @@ static bool statefiles_write_state(time_t now)
 		}
 	}
 
-	fclose(ctxt.fp);
-	md5_end(newmd5, &ctxt.md5);
+	if (ctxt.fp) {
+		fclose(ctxt.fp);
 
-	renameat(config.dhcp_statedir_fd, tmp_statefile,
-		 config.dhcp_statedir_fd, config.dhcp_statefile);
+		renameat(config.dhcp_statedir_fd, tmp_statefile,
+			 config.dhcp_statedir_fd, config.dhcp_statefile);
+	}
 
+	md5_end(newmd5, &ctxt.md5);
 	if (!memcmp(newmd5, statemd5, sizeof(newmd5)))
 		return false;
 
 	memcpy(statemd5, newmd5, sizeof(statemd5));
-
 	return true;
 
 err: