1 files changed, 226 insertions, 205 deletions

diff --git a/daemon.c b/daemon.c
index 4602b46a5c..d3d3e433e3 100644
--- a/daemon.c
+++ b/daemon.c
@@ -9,10 +9,6 @@
 #define HOST_NAME_MAX 256
 #endif
 
-#ifndef NI_MAXSERV
-#define NI_MAXSERV 32
-#endif
-
 #ifdef NO_INITGROUPS
 #define initgroups(x, y) (0) /* nothing */
 #endif
@@ -43,13 +39,10 @@ static int strict_paths;
 static int export_all_trees;
 
 /* Take all paths relative to this one if non-NULL */
-static char *base_path;
-static char *interpolated_path;
+static const char *base_path;
+static const char *interpolated_path;
 static int base_path_relaxed;
 
-/* Flag indicating client sent extra args. */
-static int saw_extended_args;
-
 /* If defined, ~user notation is allowed and the string is inserted
  * after ~user/.  E.g. a request to git://host/~alice/frotz would
  * go to /home/alice/pub_git/frotz with --user-path=pub_git.
@@ -60,10 +53,28 @@ static const char *user_path;
 static unsigned int timeout;
 static unsigned int init_timeout;
 
-static char *hostname;
-static char *canon_hostname;
-static char *ip_address;
-static char *tcp_port;
+struct hostinfo {
+	struct strbuf hostname;
+	struct strbuf canon_hostname;
+	struct strbuf ip_address;
+	struct strbuf tcp_port;
+	unsigned int hostname_lookup_done:1;
+	unsigned int saw_extended_args:1;
+};
+
+static void lookup_hostname(struct hostinfo *hi);
+
+static const char *get_canon_hostname(struct hostinfo *hi)
+{
+	lookup_hostname(hi);
+	return hi->canon_hostname.buf;
+}
+
+static const char *get_ip_address(struct hostinfo *hi)
+{
+	lookup_hostname(hi);
+	return hi->ip_address.buf;
+}
 
 static void logreport(int priority, const char *err, va_list params)
 {
@@ -110,12 +121,48 @@ static void NORETURN daemon_die(const char *err, va_list params)
 	exit(1);
 }
 
-static const char *path_ok(char *directory)
+struct expand_path_context {
+	const char *directory;
+	struct hostinfo *hostinfo;
+};
+
+static size_t expand_path(struct strbuf *sb, const char *placeholder, void *ctx)
+{
+	struct expand_path_context *context = ctx;
+	struct hostinfo *hi = context->hostinfo;
+
+	switch (placeholder[0]) {
+	case 'H':
+		strbuf_addbuf(sb, &hi->hostname);
+		return 1;
+	case 'C':
+		if (placeholder[1] == 'H') {
+			strbuf_addstr(sb, get_canon_hostname(hi));
+			return 2;
+		}
+		break;
+	case 'I':
+		if (placeholder[1] == 'P') {
+			strbuf_addstr(sb, get_ip_address(hi));
+			return 2;
+		}
+		break;
+	case 'P':
+		strbuf_addbuf(sb, &hi->tcp_port);
+		return 1;
+	case 'D':
+		strbuf_addstr(sb, context->directory);
+		return 1;
+	}
+	return 0;
+}
+
+static const char *path_ok(const char *directory, struct hostinfo *hi)
 {
 	static char rpath[PATH_MAX];
 	static char interp_path[PATH_MAX];
 	const char *path;
-	char *dir;
+	const char *dir;
 
 	dir = directory;
 
@@ -135,7 +182,7 @@ static const char *path_ok(char *directory)
 			 * "~alice/%s/foo".
 			 */
 			int namlen, restlen = strlen(dir);
-			char *slash = strchr(dir, '/');
+			const char *slash = strchr(dir, '/');
 			if (!slash)
 				slash = dir + restlen;
 			namlen = slash - dir;
@@ -146,16 +193,13 @@ static const char *path_ok(char *directory)
 			dir = rpath;
 		}
 	}
-	else if (interpolated_path && saw_extended_args) {
+	else if (interpolated_path && hi->saw_extended_args) {
 		struct strbuf expanded_path = STRBUF_INIT;
-		struct strbuf_expand_dict_entry dict[6];
-
-		dict[0].placeholder = "H"; dict[0].value = hostname;
-		dict[1].placeholder = "CH"; dict[1].value = canon_hostname;
-		dict[2].placeholder = "IP"; dict[2].value = ip_address;
-		dict[3].placeholder = "P"; dict[3].value = tcp_port;
-		dict[4].placeholder = "D"; dict[4].value = directory;
-		dict[5].placeholder = NULL; dict[5].value = NULL;
+		struct expand_path_context context;
+
+		context.directory = directory;
+		context.hostinfo = hi;
+
 		if (*dir != '/') {
 			/* Allow only absolute */
 			logerror("'%s': Non-absolute path denied (interpolated-path active)", dir);
@@ -163,7 +207,7 @@ static const char *path_ok(char *directory)
 		}
 
 		strbuf_expand(&expanded_path, interpolated_path,
-				strbuf_expand_dict_cb, &dict);
+			      expand_path, &context);
 		strlcpy(interp_path, expanded_path.buf, PATH_MAX);
 		strbuf_release(&expanded_path);
 		loginfo("Interpolated dir '%s'", interp_path);
@@ -234,21 +278,6 @@ struct daemon_service {
 	int overridable;
 };
 
-static struct daemon_service *service_looking_at;
-static int service_enabled;
-
-static int git_daemon_config(const char *var, const char *value, void *cb)
-{
-	if (!prefixcmp(var, "daemon.") &&
-	    !strcmp(var + 7, service_looking_at->config_name)) {
-		service_enabled = git_config_bool(var, value);
-		return 0;
-	}
-
-	/* we are not interested in parsing any other configuration here */
-	return 0;
-}
-
 static int daemon_error(const char *dir, const char *msg)
 {
 	if (!informative_errors)
@@ -257,29 +286,27 @@ static int daemon_error(const char *dir, const char *msg)
 	return -1;
 }
 
-static char *access_hook;
+static const char *access_hook;
 
-static int run_access_hook(struct daemon_service *service, const char *dir, const char *path)
+static int run_access_hook(struct daemon_service *service, const char *dir,
+			   const char *path, struct hostinfo *hi)
 {
-	struct child_process child;
+	struct child_process child = CHILD_PROCESS_INIT;
 	struct strbuf buf = STRBUF_INIT;
 	const char *argv[8];
 	const char **arg = argv;
 	char *eol;
 	int seen_errors = 0;
 
-#define STRARG(x) ((x) ? (x) : "")
 	*arg++ = access_hook;
 	*arg++ = service->name;
 	*arg++ = path;
-	*arg++ = STRARG(hostname);
-	*arg++ = STRARG(canon_hostname);
-	*arg++ = STRARG(ip_address);
-	*arg++ = STRARG(tcp_port);
+	*arg++ = hi->hostname.buf;
+	*arg++ = get_canon_hostname(hi);
+	*arg++ = get_ip_address(hi);
+	*arg++ = hi->tcp_port.buf;
 	*arg = NULL;
-#undef STRARG
 
-	memset(&child, 0, sizeof(child));
 	child.use_shell = 1;
 	child.argv = argv;
 	child.no_stdin = 1;
@@ -322,10 +349,12 @@ error_return:
 	return -1;
 }
 
-static int run_service(char *dir, struct daemon_service *service)
+static int run_service(const char *dir, struct daemon_service *service,
+		       struct hostinfo *hi)
 {
 	const char *path;
 	int enabled = service->enabled;
+	struct strbuf var = STRBUF_INIT;
 
 	loginfo("Request %s for '%s'", service->name, dir);
 
@@ -335,7 +364,7 @@ static int run_service(char *dir, struct daemon_service *service)
 		return daemon_error(dir, "service not enabled");
 	}
 
-	if (!(path = path_ok(dir)))
+	if (!(path = path_ok(dir, hi)))
 		return daemon_error(dir, "no such repository");
 
 	/*
@@ -356,11 +385,9 @@ static int run_service(char *dir, struct daemon_service *service)
 	}
 
 	if (service->overridable) {
-		service_looking_at = service;
-		service_enabled = -1;
-		git_config(git_daemon_config, NULL);
-		if (0 <= service_enabled)
-			enabled = service_enabled;
+		strbuf_addf(&var, "daemon.%s", service->config_name);
+		git_config_get_bool(var.buf, &enabled);
+		strbuf_release(&var);
 	}
 	if (!enabled) {
 		logerror("'%s': service not enabled for '%s'",
@@ -373,7 +400,7 @@ static int run_service(char *dir, struct daemon_service *service)
 	 * Optionally, a hook can choose to deny access to the
 	 * repository depending on the phase of the moon.
 	 */
-	if (access_hook && run_access_hook(service, dir, path))
+	if (access_hook && run_access_hook(service, dir, path, hi))
 		return -1;
 
 	/*
@@ -408,9 +435,8 @@ static void copy_to_log(int fd)
 
 static int run_service_command(const char **argv)
 {
-	struct child_process cld;
+	struct child_process cld = CHILD_PROCESS_INIT;
 
-	memset(&cld, 0, sizeof(cld));
 	cld.argv = argv;
 	cld.git_cmd = 1;
 	cld.err = -1;
@@ -479,14 +505,6 @@ static void make_service_overridable(const char *name, int ena)
 	die("No such service %s", name);
 }
 
-static char *xstrdup_tolower(const char *str)
-{
-	char *p, *dup = xstrdup(str);
-	for (p = dup; *p; p++)
-		*p = tolower(*p);
-	return dup;
-}
-
 static void parse_host_and_port(char *hostport, char **host,
 	char **port)
 {
@@ -515,16 +533,46 @@ static void parse_host_and_port(char *hostport, char **host,
 }
 
 /*
+ * Sanitize a string from the client so that it's OK to be inserted into a
+ * filesystem path. Specifically, we disallow slashes, runs of "..", and
+ * trailing and leading dots, which means that the client cannot escape
+ * our base path via ".." traversal.
+ */
+static void sanitize_client(struct strbuf *out, const char *in)
+{
+	for (; *in; in++) {
+		if (*in == '/')
+			continue;
+		if (*in == '.' && (!out->len || out->buf[out->len - 1] == '.'))
+			continue;
+		strbuf_addch(out, *in);
+	}
+
+	while (out->len && out->buf[out->len - 1] == '.')
+		strbuf_setlen(out, out->len - 1);
+}
+
+/*
+ * Like sanitize_client, but we also perform any canonicalization
+ * to make life easier on the admin.
+ */
+static void canonicalize_client(struct strbuf *out, const char *in)
+{
+	sanitize_client(out, in);
+	strbuf_tolower(out);
+}
+
+/*
  * Read the host as supplied by the client connection.
  */
-static void parse_host_arg(char *extra_args, int buflen)
+static void parse_host_arg(struct hostinfo *hi, char *extra_args, int buflen)
 {
 	char *val;
 	int vallen;
 	char *end = extra_args + buflen;
 
 	if (extra_args < end && *extra_args) {
-		saw_extended_args = 1;
+		hi->saw_extended_args = 1;
 		if (strncasecmp("host=", extra_args, 5) == 0) {
 			val = extra_args + 5;
 			vallen = strlen(val) + 1;
@@ -533,12 +581,10 @@ static void parse_host_arg(char *extra_args, int buflen)
 				char *host;
 				char *port;
 				parse_host_and_port(val, &host, &port);
-				if (port) {
-					free(tcp_port);
-					tcp_port = xstrdup(port);
-				}
-				free(hostname);
-				hostname = xstrdup_tolower(host);
+				if (port)
+					sanitize_client(&hi->tcp_port, port);
+				canonicalize_client(&hi->hostname, host);
+				hi->hostname_lookup_done = 0;
 			}
 
 			/* On to the next one */
@@ -547,11 +593,14 @@ static void parse_host_arg(char *extra_args, int buflen)
 		if (extra_args < end && *extra_args)
 			die("Invalid request");
 	}
+}
 
-	/*
-	 * Locate canonical hostname and its IP address.
-	 */
-	if (hostname) {
+/*
+ * Locate canonical hostname and its IP address.
+ */
+static void lookup_hostname(struct hostinfo *hi)
+{
+	if (!hi->hostname_lookup_done && hi->hostname.len) {
 #ifndef NO_IPV6
 		struct addrinfo hints;
 		struct addrinfo *ai;
@@ -561,18 +610,20 @@ static void parse_host_arg(char *extra_args, int buflen)
 		memset(&hints, 0, sizeof(hints));
 		hints.ai_flags = AI_CANONNAME;
 
-		gai = getaddrinfo(hostname, NULL, &hints, &ai);
+		gai = getaddrinfo(hi->hostname.buf, NULL, &hints, &ai);
 		if (!gai) {
 			struct sockaddr_in *sin_addr = (void *)ai->ai_addr;
 
 			inet_ntop(AF_INET, &sin_addr->sin_addr,
 				  addrbuf, sizeof(addrbuf));
-			free(ip_address);
-			ip_address = xstrdup(addrbuf);
+			strbuf_addstr(&hi->ip_address, addrbuf);
 
-			free(canon_hostname);
-			canon_hostname = xstrdup(ai->ai_canonname ?
-						 ai->ai_canonname : ip_address);
+			if (ai->ai_canonname)
+				sanitize_client(&hi->canon_hostname,
+						ai->ai_canonname);
+			else
+				strbuf_addbuf(&hi->canon_hostname,
+					      &hi->ip_address);
 
 			freeaddrinfo(ai);
 		}
@@ -582,37 +633,56 @@ static void parse_host_arg(char *extra_args, int buflen)
 		char **ap;
 		static char addrbuf[HOST_NAME_MAX + 1];
 
-		hent = gethostbyname(hostname);
-
-		ap = hent->h_addr_list;
-		memset(&sa, 0, sizeof sa);
-		sa.sin_family = hent->h_addrtype;
-		sa.sin_port = htons(0);
-		memcpy(&sa.sin_addr, *ap, hent->h_length);
+		hent = gethostbyname(hi->hostname.buf);
+		if (hent) {
+			ap = hent->h_addr_list;
+			memset(&sa, 0, sizeof sa);
+			sa.sin_family = hent->h_addrtype;
+			sa.sin_port = htons(0);
+			memcpy(&sa.sin_addr, *ap, hent->h_length);
 
-		inet_ntop(hent->h_addrtype, &sa.sin_addr,
-			  addrbuf, sizeof(addrbuf));
+			inet_ntop(hent->h_addrtype, &sa.sin_addr,
+				  addrbuf, sizeof(addrbuf));
 
-		free(canon_hostname);
-		canon_hostname = xstrdup(hent->h_name);
-		free(ip_address);
-		ip_address = xstrdup(addrbuf);
+			sanitize_client(&hi->canon_hostname, hent->h_name);
+			strbuf_addstr(&hi->ip_address, addrbuf);
+		}
 #endif
+		hi->hostname_lookup_done = 1;
 	}
 }
 
+static void hostinfo_init(struct hostinfo *hi)
+{
+	memset(hi, 0, sizeof(*hi));
+	strbuf_init(&hi->hostname, 0);
+	strbuf_init(&hi->canon_hostname, 0);
+	strbuf_init(&hi->ip_address, 0);
+	strbuf_init(&hi->tcp_port, 0);
+}
+
+static void hostinfo_clear(struct hostinfo *hi)
+{
+	strbuf_release(&hi->hostname);
+	strbuf_release(&hi->canon_hostname);
+	strbuf_release(&hi->ip_address);
+	strbuf_release(&hi->tcp_port);
+}
 
 static int execute(void)
 {
-	static char line[1000];
+	char *line = packet_buffer;
 	int pktlen, len, i;
 	char *addr = getenv("REMOTE_ADDR"), *port = getenv("REMOTE_PORT");
+	struct hostinfo hi;
+
+	hostinfo_init(&hi);
 
 	if (addr)
 		loginfo("Connection from %s:%s", addr, port);
 
 	alarm(init_timeout ? init_timeout : timeout);
-	pktlen = packet_read_line(0, line, sizeof(line));
+	pktlen = packet_read(0, NULL, NULL, packet_buffer, sizeof(packet_buffer), 0);
 	alarm(0);
 
 	len = strlen(line);
@@ -625,29 +695,27 @@ static int execute(void)
 		pktlen--;
 	}
 
-	free(hostname);
-	free(canon_hostname);
-	free(ip_address);
-	free(tcp_port);
-	hostname = canon_hostname = ip_address = tcp_port = NULL;
-
 	if (len != pktlen)
-		parse_host_arg(line + len + 1, pktlen - len - 1);
+		parse_host_arg(&hi, line + len + 1, pktlen - len - 1);
 
 	for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
 		struct daemon_service *s = &(daemon_service[i]);
-		int namelen = strlen(s->name);
-		if (!prefixcmp(line, "git-") &&
-		    !strncmp(s->name, line + 4, namelen) &&
-		    line[namelen + 4] == ' ') {
+		const char *arg;
+
+		if (skip_prefix(line, "git-", &arg) &&
+		    skip_prefix(arg, s->name, &arg) &&
+		    *arg++ == ' ') {
 			/*
 			 * Note: The directory here is probably context sensitive,
 			 * and might depend on the actual service being performed.
 			 */
-			return run_service(line + namelen + 5, s);
+			int rc = run_service(arg, s, &hi);
+			hostinfo_clear(&hi);
+			return rc;
 		}
 	}
 
+	hostinfo_clear(&hi);
 	logerror("Protocol error: '%s'", line);
 	return -1;
 }
@@ -742,7 +810,7 @@ static void check_dead_children(void)
 static char **cld_argv;
 static void handle(int incoming, struct sockaddr *addr, socklen_t addrlen)
 {
-	struct child_process cld = { NULL };
+	struct child_process cld = CHILD_PROCESS_INIT;
 	char addrbuf[300] = "REMOTE_ADDR=", portbuf[300];
 	char *env[] = { addrbuf, portbuf, NULL };
 
@@ -764,7 +832,7 @@ static void handle(int incoming, struct sockaddr *addr, socklen_t addrlen)
 		snprintf(portbuf, sizeof(portbuf), "REMOTE_PORT=%d",
 		    ntohs(sin_addr->sin_port));
 #ifndef NO_IPV6
-	} else if (addr && addr->sa_family == AF_INET6) {
+	} else if (addr->sa_family == AF_INET6) {
 		struct sockaddr_in6 *sin6_addr = (void *) addr;
 
 		char *buf = addrbuf + 12;
@@ -787,7 +855,6 @@ static void handle(int incoming, struct sockaddr *addr, socklen_t addrlen)
 		logerror("unable to fork");
 	else
 		add_child(&cld, addr, addrlen);
-	close(incoming);
 }
 
 static void child_handler(int signo)
@@ -844,7 +911,6 @@ static const char *ip2str(int family, struct sockaddr *sin, socklen_t len)
 static int setup_named_sock(char *listen_addr, int listen_port, struct socketlist *socklist)
 {
 	int socknum = 0;
-	int maxfd = -1;
 	char pbuf[NI_MAXSERV];
 	struct addrinfo hints, *ai0, *ai;
 	int gai;
@@ -912,9 +978,6 @@ static int setup_named_sock(char *listen_addr, int listen_port, struct socketlis
 		ALLOC_GROW(socklist->list, socklist->nr + 1, socklist->alloc);
 		socklist->list[socklist->nr++] = sockfd;
 		socknum++;
-
-		if (maxfd < sockfd)
-			maxfd = sockfd;
 	}
 
 	freeaddrinfo(ai0);
@@ -953,7 +1016,7 @@ static int setup_named_sock(char *listen_addr, int listen_port, struct socketlis
 	}
 
 	if ( bind(sockfd, (struct sockaddr *)&sin, sizeof sin) < 0 ) {
-		logerror("Could not listen to %s: %s",
+		logerror("Could not bind to %s: %s",
 			 ip2str(AF_INET, (struct sockaddr *)&sin, sizeof(sin)),
 			 strerror(errno));
 		close(sockfd);
@@ -1051,18 +1114,6 @@ static int service_loop(struct socketlist *socklist)
 	}
 }
 
-/* if any standard file descriptor is missing open it to /dev/null */
-static void sanitize_stdfds(void)
-{
-	int fd = open("/dev/null", O_RDWR, 0);
-	while (fd != -1 && fd < 2)
-		fd = dup(fd);
-	if (fd == -1)
-		die_errno("open /dev/null or dup failed");
-	if (fd > 2)
-		close(fd);
-}
-
 #ifdef NO_POSIX_GOODIES
 
 struct credentials;
@@ -1072,11 +1123,6 @@ static void drop_privileges(struct credentials *cred)
 	/* nothing */
 }
 
-static void daemonize(void)
-{
-	die("--detach not supported on this platform");
-}
-
 static struct credentials *prepare_credentials(const char *user_name,
     const char *group_name)
 {
@@ -1118,35 +1164,8 @@ static struct credentials *prepare_credentials(const char *user_name,
 
 	return &c;
 }
-
-static void daemonize(void)
-{
-	switch (fork()) {
-		case 0:
-			break;
-		case -1:
-			die_errno("fork failed");
-		default:
-			exit(0);
-	}
-	if (setsid() == -1)
-		die_errno("setsid failed");
-	close(0);
-	close(1);
-	close(2);
-	sanitize_stdfds();
-}
 #endif
 
-static void store_pid(const char *path)
-{
-	FILE *f = fopen(path, "w");
-	if (!f)
-		die_errno("cannot open pid file '%s'", path);
-	if (fprintf(f, "%"PRIuMAX"\n", (uintmax_t) getpid()) < 0 || fclose(f) != 0)
-		die_errno("failed to write pid file '%s'", path);
-}
-
 static int serve(struct string_list *listen_addr, int listen_port,
     struct credentials *cred)
 {
@@ -1180,16 +1199,17 @@ int main(int argc, char **argv)
 
 	for (i = 1; i < argc; i++) {
 		char *arg = argv[i];
+		const char *v;
 
-		if (!prefixcmp(arg, "--listen=")) {
-			string_list_append(&listen_addr, xstrdup_tolower(arg + 9));
+		if (skip_prefix(arg, "--listen=", &v)) {
+			string_list_append(&listen_addr, xstrdup_tolower(v));
 			continue;
 		}
-		if (!prefixcmp(arg, "--port=")) {
+		if (skip_prefix(arg, "--port=", &v)) {
 			char *end;
 			unsigned long n;
-			n = strtoul(arg+7, &end, 0);
-			if (arg[7] && !*end) {
+			n = strtoul(v, &end, 0);
+			if (*v && !*end) {
 				listen_port = n;
 				continue;
 			}
@@ -1215,20 +1235,20 @@ int main(int argc, char **argv)
 			export_all_trees = 1;
 			continue;
 		}
-		if (!prefixcmp(arg, "--access-hook=")) {
-			access_hook = arg + 14;
+		if (skip_prefix(arg, "--access-hook=", &v)) {
+			access_hook = v;
 			continue;
 		}
-		if (!prefixcmp(arg, "--timeout=")) {
-			timeout = atoi(arg+10);
+		if (skip_prefix(arg, "--timeout=", &v)) {
+			timeout = atoi(v);
 			continue;
 		}
-		if (!prefixcmp(arg, "--init-timeout=")) {
-			init_timeout = atoi(arg+15);
+		if (skip_prefix(arg, "--init-timeout=", &v)) {
+			init_timeout = atoi(v);
 			continue;
 		}
-		if (!prefixcmp(arg, "--max-connections=")) {
-			max_connections = atoi(arg+18);
+		if (skip_prefix(arg, "--max-connections=", &v)) {
+			max_connections = atoi(v);
 			if (max_connections < 0)
 				max_connections = 0;	        /* unlimited */
 			continue;
@@ -1237,16 +1257,16 @@ int main(int argc, char **argv)
 			strict_paths = 1;
 			continue;
 		}
-		if (!prefixcmp(arg, "--base-path=")) {
-			base_path = arg+12;
+		if (skip_prefix(arg, "--base-path=", &v)) {
+			base_path = v;
 			continue;
 		}
 		if (!strcmp(arg, "--base-path-relaxed")) {
 			base_path_relaxed = 1;
 			continue;
 		}
-		if (!prefixcmp(arg, "--interpolated-path=")) {
-			interpolated_path = arg+20;
+		if (skip_prefix(arg, "--interpolated-path=", &v)) {
+			interpolated_path = v;
 			continue;
 		}
 		if (!strcmp(arg, "--reuseaddr")) {
@@ -1257,12 +1277,12 @@ int main(int argc, char **argv)
 			user_path = "";
 			continue;
 		}
-		if (!prefixcmp(arg, "--user-path=")) {
-			user_path = arg + 12;
+		if (skip_prefix(arg, "--user-path=", &v)) {
+			user_path = v;
 			continue;
 		}
-		if (!prefixcmp(arg, "--pid-file=")) {
-			pid_file = arg + 11;
+		if (skip_prefix(arg, "--pid-file=", &v)) {
+			pid_file = v;
 			continue;
 		}
 		if (!strcmp(arg, "--detach")) {
@@ -1270,35 +1290,35 @@ int main(int argc, char **argv)
 			log_syslog = 1;
 			continue;
 		}
-		if (!prefixcmp(arg, "--user=")) {
-			user_name = arg + 7;
+		if (skip_prefix(arg, "--user=", &v)) {
+			user_name = v;
 			continue;
 		}
-		if (!prefixcmp(arg, "--group=")) {
-			group_name = arg + 8;
+		if (skip_prefix(arg, "--group=", &v)) {
+			group_name = v;
 			continue;
 		}
-		if (!prefixcmp(arg, "--enable=")) {
-			enable_service(arg + 9, 1);
+		if (skip_prefix(arg, "--enable=", &v)) {
+			enable_service(v, 1);
 			continue;
 		}
-		if (!prefixcmp(arg, "--disable=")) {
-			enable_service(arg + 10, 0);
+		if (skip_prefix(arg, "--disable=", &v)) {
+			enable_service(v, 0);
 			continue;
 		}
-		if (!prefixcmp(arg, "--allow-override=")) {
-			make_service_overridable(arg + 17, 1);
+		if (skip_prefix(arg, "--allow-override=", &v)) {
+			make_service_overridable(v, 1);
 			continue;
 		}
-		if (!prefixcmp(arg, "--forbid-override=")) {
-			make_service_overridable(arg + 18, 0);
+		if (skip_prefix(arg, "--forbid-override=", &v)) {
+			make_service_overridable(v, 0);
 			continue;
 		}
-		if (!prefixcmp(arg, "--informative-errors")) {
+		if (!strcmp(arg, "--informative-errors")) {
 			informative_errors = 1;
 			continue;
 		}
-		if (!prefixcmp(arg, "--no-informative-errors")) {
+		if (!strcmp(arg, "--no-informative-errors")) {
 			informative_errors = 0;
 			continue;
 		}
@@ -1349,13 +1369,14 @@ int main(int argc, char **argv)
 	if (inetd_mode || serve_mode)
 		return execute();
 
-	if (detach)
-		daemonize();
-	else
+	if (detach) {
+		if (daemonize())
+			die("--detach not supported on this platform");
+	} else
 		sanitize_stdfds();
 
 	if (pid_file)
-		store_pid(pid_file);
+		write_file(pid_file, 1, "%"PRIuMAX"\n", (uintmax_t) getpid());
 
 	/* prepare argv for serving-processes */
 	cld_argv = xmalloc(sizeof (char *) * (argc + 2));