udhcp: new config option "Rewrite the lease file at every new acknowledge"

       (Mats Erik Andersson <mats@blue2net.com> (Blue2Net AB))
udhcp: consistently treat server_config.start/end IPs as host-order
       fix IP parsing for 64bit machines
       fix unsafe hton macro usage in read_opt()
       do not chdir("/") when daemonizing
       fix help text

1 files changed, 92 insertions, 69 deletions

diff --git a/networking/udhcp/files.c b/networking/udhcp/files.c
index 41c8717..7fc7348 100644
--- a/networking/udhcp/files.c
+++ b/networking/udhcp/files.c
@@ -11,42 +11,30 @@
 #include "options.h"
 
 
-/*
- * Domain names may have 254 chars, and string options can be 254
- * chars long. However, 80 bytes will be enough for most, and won't
- * hog up memory. If you have a special application, change it
- */
-#define READ_CONFIG_BUF_SIZE 80
-
-/* on these functions, make sure you datatype matches */
+/* on these functions, make sure your datatype matches */
 static int read_ip(const char *line, void *arg)
 {
 	len_and_sockaddr *lsa;
-	int retval = 0;
 
 	lsa = host_and_af2sockaddr(line, 0, AF_INET);
 	if (lsa) {
-		*(struct in_addr*)arg = lsa->sin.sin_addr;
+		*(uint32_t*)arg = lsa->sin.sin_addr.s_addr;
 		free(lsa);
-		retval = 1;
+		return 1;
 	}
-	return retval;
+	return 0;
 }
 
 static int read_mac(const char *line, void *arg)
 {
 	uint8_t *mac_bytes = arg;
 	struct ether_addr *temp_ether_addr;
-	int retval = 1;
 
 	temp_ether_addr = ether_aton(line);
-
 	if (temp_ether_addr == NULL)
-		retval = 0;
-	else
-		memcpy(mac_bytes, temp_ether_addr, 6);
-
-	return retval;
+		return 0;
+	memcpy(mac_bytes, temp_ether_addr, 6);
+	return 1;
 }
 
 
@@ -56,14 +44,13 @@ static int read_str(const char *line, void *arg)
 
 	free(*dest);
 	*dest = xstrdup(line);
-
 	return 1;
 }
 
 
 static int read_u32(const char *line, void *arg)
 {
-	*((uint32_t*)arg) = bb_strtou32(line, NULL, 10);
+	*(uint32_t*)arg = bb_strtou32(line, NULL, 10);
 	return errno == 0;
 }
 
@@ -71,15 +58,16 @@ static int read_u32(const char *line, void *arg)
 static int read_yn(const char *line, void *arg)
 {
 	char *dest = arg;
-	int retval = 1;
 
-	if (!strcasecmp("yes", line))
+	if (!strcasecmp("yes", line)) {
 		*dest = 1;
-	else if (!strcasecmp("no", line))
+		return 1;
+	}
+	if (!strcasecmp("no", line)) {
 		*dest = 0;
-	else retval = 0;
-
-	return retval;
+		return 1;
+	}
+	return 0;
 }
 
 
@@ -89,8 +77,9 @@ struct option_set *find_option(struct option_set *opt_list, char code)
 	while (opt_list && opt_list->data[OPT_CODE] < code)
 		opt_list = opt_list->next;
 
-	if (opt_list && opt_list->data[OPT_CODE] == code) return opt_list;
-	else return NULL;
+	if (opt_list && opt_list->data[OPT_CODE] == code)
+		return opt_list;
+	return NULL;
 }
 
 
@@ -111,7 +100,7 @@ static void attach_option(struct option_set **opt_list,
 #endif
 
 		/* make a new option */
-		new = xmalloc(sizeof(struct option_set));
+		new = xmalloc(sizeof(*new));
 		new->data = xmalloc(length + 2);
 		new->data[OPT_CODE] = option->code;
 		new->data[OPT_LEN] = length;
@@ -184,7 +173,7 @@ static int read_opt(const char *const_line, void *arg)
 			return 0;
 		if (!strcasecmp(option->name, opt))
 			break;
-		 option++;
+		option++;
 	}
 
 	do {
@@ -199,8 +188,11 @@ static int read_opt(const char *const_line, void *arg)
 			break;
 		case OPTION_IP_PAIR:
 			retval = read_ip(val, buffer);
-			if (!(val = strtok(NULL, ", \t/-"))) retval = 0;
-			if (retval) retval = read_ip(val, buffer + 4);
+			val = strtok(NULL, ", \t/-");
+			if (!val)
+				retval = 0;
+			if (retval)
+				retval = read_ip(val, buffer + 4);
 			break;
 		case OPTION_STRING:
 #if ENABLE_FEATURE_RFC3397
@@ -220,22 +212,33 @@ static int read_opt(const char *const_line, void *arg)
 			buffer[0] = strtoul(val, &endptr, 0);
 			retval = (endptr[0] == '\0');
 			break;
-		case OPTION_U16:
-			*result_u16 = htons(strtoul(val, &endptr, 0));
-			retval = (endptr[0] == '\0');
+		/* htonX are macros in older libc's, using temp var
+		 * in code below for safety */
+		/* TODO: use bb_strtoX? */
+		case OPTION_U16: {
+			unsigned long tmp = strtoul(val, &endptr, 0);
+			*result_u16 = htons(tmp);
+			retval = (endptr[0] == '\0' /*&& tmp < 0x10000*/);
 			break;
-		case OPTION_S16:
-			*result_u16 = htons(strtol(val, &endptr, 0));
+		}
+		case OPTION_S16: {
+			long tmp = strtol(val, &endptr, 0);
+			*result_u16 = htons(tmp);
 			retval = (endptr[0] == '\0');
 			break;
-		case OPTION_U32:
-			*result_u32 = htonl(strtoul(val, &endptr, 0));
+		}
+		case OPTION_U32: {
+			unsigned long tmp = strtoul(val, &endptr, 0);
+			*result_u32 = htonl(tmp);
 			retval = (endptr[0] == '\0');
 			break;
-		case OPTION_S32:
-			*result_u32 = htonl(strtol(val, &endptr, 0));
+		}
+		case OPTION_S32: {
+			long tmp = strtol(val, &endptr, 0);
+			*result_u32 = htonl(tmp);
 			retval = (endptr[0] == '\0');
 			break;
+		}
 		default:
 			break;
 		}
@@ -253,7 +256,6 @@ static int read_staticlease(const char *const_line, void *arg)
 	uint8_t *mac_bytes;
 	uint32_t *ip;
 
-
 	/* Allocate memory for addresses */
 	mac_bytes = xmalloc(sizeof(unsigned char) * 8);
 	ip = xmalloc(sizeof(uint32_t));
@@ -275,39 +277,54 @@ static int read_staticlease(const char *const_line, void *arg)
 }
 
 
+struct config_keyword {
+	const char *keyword;
+	int (*handler)(const char *line, void *var);
+	void *var;
+	const char *def;
+};
+
 static const struct config_keyword keywords[] = {
-	/* keyword	handler   variable address		default */
-	{"start",	read_ip,  &(server_config.start),	"192.168.0.20"},
-	{"end",		read_ip,  &(server_config.end),		"192.168.0.254"},
-	{"interface",	read_str, &(server_config.interface),	"eth0"},
-	{"option",	read_opt, &(server_config.options),	""},
-	{"opt",		read_opt, &(server_config.options),	""},
-	{"max_leases",	read_u32, &(server_config.max_leases),	"254"},
-	{"remaining",	read_yn,  &(server_config.remaining),	"yes"},
-	{"auto_time",	read_u32, &(server_config.auto_time),	"7200"},
-	{"decline_time",read_u32, &(server_config.decline_time),"3600"},
-	{"conflict_time",read_u32,&(server_config.conflict_time),"3600"},
-	{"offer_time",	read_u32, &(server_config.offer_time),	"60"},
-	{"min_lease",	read_u32, &(server_config.min_lease),	"60"},
-	{"lease_file",	read_str, &(server_config.lease_file),	LEASES_FILE},
-	{"pidfile",	read_str, &(server_config.pidfile),	"/var/run/udhcpd.pid"},
-	{"notify_file", read_str, &(server_config.notify_file),	""},
-	{"siaddr",	read_ip,  &(server_config.siaddr),	"0.0.0.0"},
-	{"sname",	read_str, &(server_config.sname),	""},
-	{"boot_file",	read_str, &(server_config.boot_file),	""},
-	{"static_lease",read_staticlease, &(server_config.static_leases),	""},
-	/*ADDME: static lease */
-	{"",		NULL,	  NULL,				""}
+	/* keyword       handler   variable address               default */
+	{"start",        read_ip,  &(server_config.start_ip),     "192.168.0.20"},
+	{"end",          read_ip,  &(server_config.end_ip),       "192.168.0.254"},
+	{"interface",    read_str, &(server_config.interface),    "eth0"},
+	{"option",       read_opt, &(server_config.options),      ""},
+	{"opt",          read_opt, &(server_config.options),      ""},
+	/* Avoid "max_leases value not sane" warning by setting default
+	 * to default_end_ip - default_start_ip + 1: */
+	{"max_leases",   read_u32, &(server_config.max_leases),   "235"},
+	{"remaining",    read_yn,  &(server_config.remaining),    "yes"},
+	{"auto_time",    read_u32, &(server_config.auto_time),    "7200"},
+	{"decline_time", read_u32, &(server_config.decline_time), "3600"},
+	{"conflict_time",read_u32, &(server_config.conflict_time),"3600"},
+	{"offer_time",   read_u32, &(server_config.offer_time),   "60"},
+	{"min_lease",    read_u32, &(server_config.min_lease),    "60"},
+	{"lease_file",   read_str, &(server_config.lease_file),   LEASES_FILE},
+	{"pidfile",      read_str, &(server_config.pidfile),      "/var/run/udhcpd.pid"},
+	{"notify_file",  read_str, &(server_config.notify_file),  ""},
+	{"siaddr",       read_ip,  &(server_config.siaddr),       "0.0.0.0"},
+	{"sname",        read_str, &(server_config.sname),        ""},
+	{"boot_file",    read_str, &(server_config.boot_file),    ""},
+	{"static_lease", read_staticlease, &(server_config.static_leases), ""},
+	/* ADDME: static lease */
 };
 
 
+/*
+ * Domain names may have 254 chars, and string options can be 254
+ * chars long. However, 80 bytes will be enough for most, and won't
+ * hog up memory. If you have a special application, change it
+ */
+#define READ_CONFIG_BUF_SIZE 80
+
 int read_config(const char *file)
 {
 	FILE *in;
 	char buffer[READ_CONFIG_BUF_SIZE], *token, *line;
 	int i, lm = 0;
 
-	for (i = 0; keywords[i].keyword[0]; i++)
+	for (i = 0; i < ARRAY_SIZE(keywords); i++)
 		if (keywords[i].def[0])
 			keywords[i].handler(keywords[i].def, keywords[i].var);
 
@@ -337,7 +354,7 @@ int read_config(const char *file)
 		while (i >= 0 && isspace(line[i]))
 			line[i--] = '\0';
 
-		for (i = 0; keywords[i].keyword[0]; i++)
+		for (i = 0; i < ARRAY_SIZE(keywords); i++)
 			if (!strcasecmp(token, keywords[i].keyword))
 				if (!keywords[i].handler(line, keywords[i].var)) {
 					bb_error_msg("cannot parse line %d of %s", lm, file);
@@ -348,6 +365,10 @@ int read_config(const char *file)
 				}
 	}
 	fclose(in);
+
+	server_config.start_ip = ntohl(server_config.start_ip);
+	server_config.end_ip = ntohl(server_config.end_ip);
+
 	return 1;
 }
 
@@ -408,9 +429,11 @@ void read_leases(const char *file)
 	 && full_read(fp, &lease, sizeof(lease)) == sizeof(lease)
 	) {
 		/* ADDME: is it a static lease */
-		if (lease.yiaddr >= server_config.start && lease.yiaddr <= server_config.end) {
+		uint32_t y = ntohl(lease.yiaddr);
+		if (y >= server_config.start_ip && y <= server_config.end_ip) {
 			lease.expires = ntohl(lease.expires);
-			if (!server_config.remaining) lease.expires -= time(0);
+			if (!server_config.remaining)
+				lease.expires -= time(0);
 			if (!(add_lease(lease.chaddr, lease.yiaddr, lease.expires))) {
 				bb_error_msg("too many leases while loading %s", file);
 				break;