1 files changed, 807 insertions, 325 deletions

diff --git a/daemon.c b/daemon.c
index a1ccda30e2..4c8346d5a1 100644
--- a/daemon.c
+++ b/daemon.c
@@ -1,82 +1,88 @@
-#include <signal.h>
-#include <sys/wait.h>
-#include <sys/socket.h>
-#include <sys/time.h>
-#include <sys/poll.h>
-#include <netdb.h>
-#include <netinet/in.h>
-#include <arpa/inet.h>
-#include <syslog.h>
-#include "pkt-line.h"
 #include "cache.h"
+#include "pkt-line.h"
 #include "exec_cmd.h"
+#include "run-command.h"
+#include "strbuf.h"
+#include "string-list.h"
+
+#ifndef HOST_NAME_MAX
+#define HOST_NAME_MAX 256
+#endif
+
+#ifndef NI_MAXSERV
+#define NI_MAXSERV 32
+#endif
+
+#ifdef NO_INITGROUPS
+#define initgroups(x, y) (0) /* nothing */
+#endif
 
 static int log_syslog;
 static int verbose;
 static int reuseaddr;
 
 static const char daemon_usage[] =
-"git-daemon [--verbose] [--syslog] [--inetd | --port=n] [--export-all]\n"
-"           [--timeout=n] [--init-timeout=n] [--strict-paths]\n"
-"           [--base-path=path] [--user-path | --user-path=path]\n"
-"           [--reuseaddr] [directory...]";
+"git daemon [--verbose] [--syslog] [--export-all]\n"
+"           [--timeout=<n>] [--init-timeout=<n>] [--max-connections=<n>]\n"
+"           [--strict-paths] [--base-path=<path>] [--base-path-relaxed]\n"
+"           [--user-path | --user-path=<path>]\n"
+"           [--interpolated-path=<path>]\n"
+"           [--reuseaddr] [--pid-file=<file>]\n"
+"           [--(enable|disable|allow-override|forbid-override)=<service>]\n"
+"           [--inetd | [--listen=<host_or_ipaddr>] [--port=<n>]\n"
+"                      [--detach] [--user=<user> [--group=<group>]]\n"
+"           [<directory>...]";
 
 /* List of acceptable pathname prefixes */
-static char **ok_paths = NULL;
-static int strict_paths = 0;
+static char **ok_paths;
+static int strict_paths;
 
 /* If this is set, git-daemon-export-ok is not required */
-static int export_all_trees = 0;
+static int export_all_trees;
 
 /* Take all paths relative to this one if non-NULL */
-static char *base_path = NULL;
+static char *base_path;
+static 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.
  */
-static char *user_path = NULL;
+static const char *user_path;
 
 /* Timeout, and initial timeout */
-static unsigned int timeout = 0;
-static unsigned int init_timeout = 0;
+static unsigned int timeout;
+static unsigned int init_timeout;
+
+static char *hostname;
+static char *canon_hostname;
+static char *ip_address;
+static char *tcp_port;
 
 static void logreport(int priority, const char *err, va_list params)
 {
-	/* We should do a single write so that it is atomic and output
-	 * of several processes do not get intermingled. */
-	char buf[1024];
-	int buflen;
-	int maxlen, msglen;
-
-	/* sizeof(buf) should be big enough for "[pid] \n" */
-	buflen = snprintf(buf, sizeof(buf), "[%ld] ", (long) getpid());
-
-	maxlen = sizeof(buf) - buflen - 1; /* -1 for our own LF */
-	msglen = vsnprintf(buf + buflen, maxlen, err, params);
-
 	if (log_syslog) {
+		char buf[1024];
+		vsnprintf(buf, sizeof(buf), err, params);
 		syslog(priority, "%s", buf);
-		return;
+	} else {
+		/*
+		 * Since stderr is set to buffered mode, the
+		 * logging of different processes will not overlap
+		 * unless they overflow the (rather big) buffers.
+		 */
+		fprintf(stderr, "[%"PRIuMAX"] ", (uintmax_t)getpid());
+		vfprintf(stderr, err, params);
+		fputc('\n', stderr);
+		fflush(stderr);
 	}
-
-	/* maxlen counted our own LF but also counts space given to
-	 * vsnprintf for the terminating NUL.  We want to make sure that
-	 * we have space for our own LF and NUL after the "meat" of the
-	 * message, so truncate it at maxlen - 1.
-	 */
-	if (msglen > maxlen - 1)
-		msglen = maxlen - 1;
-	else if (msglen < 0)
-		msglen = 0; /* Protect against weird return values. */
-	buflen += msglen;
-
-	buf[buflen++] = '\n';
-	buf[buflen] = '\0';
-
-	write(2, buf, buflen);
 }
 
+__attribute__((format (printf, 1, 2)))
 static void logerror(const char *err, ...)
 {
 	va_list params;
@@ -85,6 +91,7 @@ static void logerror(const char *err, ...)
 	va_end(params);
 }
 
+__attribute__((format (printf, 1, 2)))
 static void loginfo(const char *err, ...)
 {
 	va_list params;
@@ -95,59 +102,22 @@ static void loginfo(const char *err, ...)
 	va_end(params);
 }
 
-static int avoid_alias(char *p)
+static void NORETURN daemon_die(const char *err, va_list params)
 {
-	int sl, ndot;
-
-	/* 
-	 * This resurrects the belts and suspenders paranoia check by HPA
-	 * done in <435560F7.4080006@zytor.com> thread, now enter_repo()
-	 * does not do getcwd() based path canonicalizations.
-	 *
-	 * sl becomes true immediately after seeing '/' and continues to
-	 * be true as long as dots continue after that without intervening
-	 * non-dot character.
-	 */
-	if (!p || (*p != '/' && *p != '~'))
-		return -1;
-	sl = 1; ndot = 0;
-	p++;
-
-	while (1) {
-		char ch = *p++;
-		if (sl) {
-			if (ch == '.')
-				ndot++;
-			else if (ch == '/') {
-				if (ndot < 3)
-					/* reject //, /./ and /../ */
-					return -1;
-				ndot = 0;
-			}
-			else if (ch == 0) {
-				if (0 < ndot && ndot < 3)
-					/* reject /.$ and /..$ */
-					return -1;
-				return 0;
-			}
-			else
-				sl = ndot = 0;
-		}
-		else if (ch == 0)
-			return 0;
-		else if (ch == '/') {
-			sl = 1;
-			ndot = 0;
-		}
-	}
+	logreport(LOG_ERR, err, params);
+	exit(1);
 }
 
-static char *path_ok(char *dir)
+static char *path_ok(char *directory)
 {
 	static char rpath[PATH_MAX];
+	static char interp_path[PATH_MAX];
 	char *path;
+	char *dir;
+
+	dir = directory;
 
-	if (avoid_alias(dir)) {
+	if (daemon_avoid_alias(dir)) {
 		logerror("'%s': aliased", dir);
 		return NULL;
 	}
@@ -174,22 +144,52 @@ static char *path_ok(char *dir)
 			dir = rpath;
 		}
 	}
+	else if (interpolated_path && 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;
+		if (*dir != '/') {
+			/* Allow only absolute */
+			logerror("'%s': Non-absolute path denied (interpolated-path active)", dir);
+			return NULL;
+		}
+
+		strbuf_expand(&expanded_path, interpolated_path,
+				strbuf_expand_dict_cb, &dict);
+		strlcpy(interp_path, expanded_path.buf, PATH_MAX);
+		strbuf_release(&expanded_path);
+		loginfo("Interpolated dir '%s'", interp_path);
+
+		dir = interp_path;
+	}
 	else if (base_path) {
 		if (*dir != '/') {
 			/* Allow only absolute */
 			logerror("'%s': Non-absolute path denied (base-path active)", dir);
 			return NULL;
 		}
-		else {
-			snprintf(rpath, PATH_MAX, "%s%s", base_path, dir);
-			dir = rpath;
-		}
+		snprintf(rpath, PATH_MAX, "%s%s", base_path, dir);
+		dir = rpath;
 	}
 
 	path = enter_repo(dir, strict_paths);
+	if (!path && base_path && base_path_relaxed) {
+		/*
+		 * if we fail and base_path_relaxed is enabled, try without
+		 * prefixing the base path
+		 */
+		dir = directory;
+		path = enter_repo(dir, strict_paths);
+	}
 
 	if (!path) {
-		logerror("'%s': unable to chdir or not a git archive", dir);
+		logerror("'%s' does not appear to be a git repository", dir);
 		return NULL;
 	}
 
@@ -198,7 +198,7 @@ static char *path_ok(char *dir)
 		int pathlen = strlen(path);
 
 		/* The validation is done on the paths after enter_repo
-		 * appends optional {.git,.git/.git} and friends, but 
+		 * appends optional {.git,.git/.git} and friends, but
 		 * it does not use getcwd().  So if your /pub is
 		 * a symlink to /mnt/pub, you can whitelist /pub and
 		 * do not have to say /mnt/pub.
@@ -223,13 +223,42 @@ static char *path_ok(char *dir)
 	return NULL;		/* Fallthrough. Deny by default */
 }
 
-static int upload(char *dir)
+typedef int (*daemon_service_fn)(void);
+struct daemon_service {
+	const char *name;
+	const char *config_name;
+	daemon_service_fn fn;
+	int enabled;
+	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 run_service(char *dir, struct daemon_service *service)
 {
-	/* Timeout as string */
-	char timeout_buf[64];
 	const char *path;
+	int enabled = service->enabled;
 
-	loginfo("Request for '%s'", dir);
+	loginfo("Request %s for '%s'", service->name, dir);
+
+	if (!enabled && !service->overridable) {
+		logerror("'%s': service not enabled.", service->name);
+		errno = EACCES;
+		return -1;
+	}
 
 	if (!(path = path_ok(dir)))
 		return -1;
@@ -251,232 +280,442 @@ static int upload(char *dir)
 		return -1;
 	}
 
+	if (service->overridable) {
+		service_looking_at = service;
+		service_enabled = -1;
+		git_config(git_daemon_config, NULL);
+		if (0 <= service_enabled)
+			enabled = service_enabled;
+	}
+	if (!enabled) {
+		logerror("'%s': service not enabled for '%s'",
+			 service->name, path);
+		errno = EACCES;
+		return -1;
+	}
+
 	/*
 	 * We'll ignore SIGTERM from now on, we have a
 	 * good client.
 	 */
 	signal(SIGTERM, SIG_IGN);
 
-	snprintf(timeout_buf, sizeof timeout_buf, "--timeout=%u", timeout);
-
-	/* git-upload-pack only ever reads stuff, so this is safe */
-	execl_git_cmd("upload-pack", "--strict", timeout_buf, ".", NULL);
-	return -1;
+	return service->fn();
 }
 
-static int execute(void)
+static void copy_to_log(int fd)
 {
-	static char line[1000];
-	int len;
+	struct strbuf line = STRBUF_INIT;
+	FILE *fp;
 
-	alarm(init_timeout ? init_timeout : timeout);
-	len = packet_read_line(0, line, sizeof(line));
-	alarm(0);
-
-	if (len && line[len-1] == '\n')
-		line[--len] = 0;
+	fp = fdopen(fd, "r");
+	if (fp == NULL) {
+		logerror("fdopen of error channel failed");
+		close(fd);
+		return;
+	}
 
-	if (!strncmp("git-upload-pack ", line, 16))
-		return upload(line+16);
+	while (strbuf_getline(&line, fp, '\n') != EOF) {
+		logerror("%s", line.buf);
+		strbuf_setlen(&line, 0);
+	}
 
-	logerror("Protocol error: '%s'", line);
-	return -1;
+	strbuf_release(&line);
+	fclose(fp);
 }
 
+static int run_service_command(const char **argv)
+{
+	struct child_process cld;
 
-/*
- * We count spawned/reaped separately, just to avoid any
- * races when updating them from signals. The SIGCHLD handler
- * will only update children_reaped, and the fork logic will
- * only update children_spawned.
- *
- * MAX_CHILDREN should be a power-of-two to make the modulus
- * operation cheap. It should also be at least twice
- * the maximum number of connections we will ever allow.
- */
-#define MAX_CHILDREN 128
+	memset(&cld, 0, sizeof(cld));
+	cld.argv = argv;
+	cld.git_cmd = 1;
+	cld.err = -1;
+	if (start_command(&cld))
+		return -1;
 
-static int max_connections = 25;
+	close(0);
+	close(1);
 
-/* These are updated by the signal handler */
-static volatile unsigned int children_reaped = 0;
-static pid_t dead_child[MAX_CHILDREN];
+	copy_to_log(cld.err);
 
-/* These are updated by the main loop */
-static unsigned int children_spawned = 0;
-static unsigned int children_deleted = 0;
+	return finish_command(&cld);
+}
 
-static struct child {
-	pid_t pid;
-	int addrlen;
-	struct sockaddr_storage address;
-} live_child[MAX_CHILDREN];
+static int upload_pack(void)
+{
+	/* Timeout as string */
+	char timeout_buf[64];
+	const char *argv[] = { "upload-pack", "--strict", NULL, ".", NULL };
+
+	argv[2] = timeout_buf;
 
-static void add_child(int idx, pid_t pid, struct sockaddr *addr, int addrlen)
+	snprintf(timeout_buf, sizeof timeout_buf, "--timeout=%u", timeout);
+	return run_service_command(argv);
+}
+
+static int upload_archive(void)
 {
-	live_child[idx].pid = pid;
-	live_child[idx].addrlen = addrlen;
-	memcpy(&live_child[idx].address, addr, addrlen);
+	static const char *argv[] = { "upload-archive", ".", NULL };
+	return run_service_command(argv);
 }
 
-/*
- * Walk from "deleted" to "spawned", and remove child "pid".
- *
- * We move everything up by one, since the new "deleted" will
- * be one higher.
- */
-static void remove_child(pid_t pid, unsigned deleted, unsigned spawned)
+static int receive_pack(void)
 {
-	struct child n;
+	static const char *argv[] = { "receive-pack", ".", NULL };
+	return run_service_command(argv);
+}
 
-	deleted %= MAX_CHILDREN;
-	spawned %= MAX_CHILDREN;
-	if (live_child[deleted].pid == pid) {
-		live_child[deleted].pid = -1;
-		return;
+static struct daemon_service daemon_service[] = {
+	{ "upload-archive", "uploadarch", upload_archive, 0, 1 },
+	{ "upload-pack", "uploadpack", upload_pack, 1, 1 },
+	{ "receive-pack", "receivepack", receive_pack, 0, 1 },
+};
+
+static void enable_service(const char *name, int ena)
+{
+	int i;
+	for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
+		if (!strcmp(daemon_service[i].name, name)) {
+			daemon_service[i].enabled = ena;
+			return;
+		}
 	}
-	n = live_child[deleted];
-	for (;;) {
-		struct child m;
-		deleted = (deleted + 1) % MAX_CHILDREN;
-		if (deleted == spawned)
-			die("could not find dead child %d\n", pid);
-		m = live_child[deleted];
-		live_child[deleted] = n;
-		if (m.pid == pid)
+	die("No such service %s", name);
+}
+
+static void make_service_overridable(const char *name, int ena)
+{
+	int i;
+	for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
+		if (!strcmp(daemon_service[i].name, name)) {
+			daemon_service[i].overridable = ena;
 			return;
-		n = m;
+		}
 	}
+	die("No such service %s", name);
 }
 
-/*
- * This gets called if the number of connections grows
- * past "max_connections".
- *
- * We _should_ start off by searching for connections
- * from the same IP, and if there is some address wth
- * multiple connections, we should kill that first.
- *
- * As it is, we just "randomly" kill 25% of the connections,
- * and our pseudo-random generator sucks too. I have no
- * shame.
- *
- * Really, this is just a place-holder for a _real_ algorithm.
- */
-static void kill_some_children(int signo, unsigned start, unsigned stop)
+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)
 {
-	start %= MAX_CHILDREN;
-	stop %= MAX_CHILDREN;
-	while (start != stop) {
-		if (!(start & 3))
-			kill(live_child[start].pid, signo);
-		start = (start + 1) % MAX_CHILDREN;
+	if (*hostport == '[') {
+		char *end;
+
+		end = strchr(hostport, ']');
+		if (!end)
+			die("Invalid request ('[' without ']')");
+		*end = '\0';
+		*host = hostport + 1;
+		if (!end[1])
+			*port = NULL;
+		else if (end[1] == ':')
+			*port = end + 2;
+		else
+			die("Garbage after end of host part");
+	} else {
+		*host = hostport;
+		*port = strrchr(hostport, ':');
+		if (*port) {
+			**port = '\0';
+			++*port;
+		}
 	}
 }
 
-static void check_max_connections(void)
+/*
+ * Read the host as supplied by the client connection.
+ */
+static void parse_host_arg(char *extra_args, int buflen)
 {
-	for (;;) {
-		int active;
-		unsigned spawned, reaped, deleted;
+	char *val;
+	int vallen;
+	char *end = extra_args + buflen;
+
+	if (extra_args < end && *extra_args) {
+		saw_extended_args = 1;
+		if (strncasecmp("host=", extra_args, 5) == 0) {
+			val = extra_args + 5;
+			vallen = strlen(val) + 1;
+			if (*val) {
+				/* Split <host>:<port> at colon. */
+				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);
+			}
+
+			/* On to the next one */
+			extra_args = val + vallen;
+		}
+		if (extra_args < end && *extra_args)
+			die("Invalid request");
+	}
+
+	/*
+	 * Locate canonical hostname and its IP address.
+	 */
+	if (hostname) {
+#ifndef NO_IPV6
+		struct addrinfo hints;
+		struct addrinfo *ai;
+		int gai;
+		static char addrbuf[HOST_NAME_MAX + 1];
+
+		memset(&hints, 0, sizeof(hints));
+		hints.ai_flags = AI_CANONNAME;
 
-		spawned = children_spawned;
-		reaped = children_reaped;
-		deleted = children_deleted;
+		gai = getaddrinfo(hostname, NULL, &hints, &ai);
+		if (!gai) {
+			struct sockaddr_in *sin_addr = (void *)ai->ai_addr;
 
-		while (deleted < reaped) {
-			pid_t pid = dead_child[deleted % MAX_CHILDREN];
-			remove_child(pid, deleted, spawned);
-			deleted++;
+			inet_ntop(AF_INET, &sin_addr->sin_addr,
+				  addrbuf, sizeof(addrbuf));
+			free(ip_address);
+			ip_address = xstrdup(addrbuf);
+
+			free(canon_hostname);
+			canon_hostname = xstrdup(ai->ai_canonname ?
+						 ai->ai_canonname : ip_address);
+
+			freeaddrinfo(ai);
 		}
-		children_deleted = deleted;
+#else
+		struct hostent *hent;
+		struct sockaddr_in sa;
+		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);
+
+		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);
+#endif
+	}
+}
 
-		active = spawned - deleted;
-		if (active <= max_connections)
-			break;
 
-		/* Kill some unstarted connections with SIGTERM */
-		kill_some_children(SIGTERM, deleted, spawned);
-		if (active <= max_connections << 1)
-			break;
+static int execute(void)
+{
+	static char line[1000];
+	int pktlen, len, i;
+	char *addr = getenv("REMOTE_ADDR"), *port = getenv("REMOTE_PORT");
+
+	if (addr)
+		loginfo("Connection from %s:%s", addr, port);
+
+	alarm(init_timeout ? init_timeout : timeout);
+	pktlen = packet_read_line(0, line, sizeof(line));
+	alarm(0);
 
-		/* If the SIGTERM thing isn't helping use SIGKILL */
-		kill_some_children(SIGKILL, deleted, spawned);
-		sleep(1);
+	len = strlen(line);
+	if (pktlen != len)
+		loginfo("Extended attributes (%d bytes) exist <%.*s>",
+			(int) pktlen - len,
+			(int) pktlen - len, line + len + 1);
+	if (len && line[len-1] == '\n') {
+		line[--len] = 0;
+		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);
+
+	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] == ' ') {
+			/*
+			 * Note: The directory here is probably context sensitive,
+			 * and might depend on the actual service being performed.
+			 */
+			return run_service(line + namelen + 5, s);
+		}
+	}
+
+	logerror("Protocol error: '%s'", line);
+	return -1;
 }
 
-static void handle(int incoming, struct sockaddr *addr, int addrlen)
+static int addrcmp(const struct sockaddr_storage *s1,
+    const struct sockaddr_storage *s2)
 {
-	pid_t pid = fork();
-	char addrbuf[256] = "";
-	int port = -1;
+	const struct sockaddr *sa1 = (const struct sockaddr*) s1;
+	const struct sockaddr *sa2 = (const struct sockaddr*) s2;
+
+	if (sa1->sa_family != sa2->sa_family)
+		return sa1->sa_family - sa2->sa_family;
+	if (sa1->sa_family == AF_INET)
+		return memcmp(&((struct sockaddr_in *)s1)->sin_addr,
+		    &((struct sockaddr_in *)s2)->sin_addr,
+		    sizeof(struct in_addr));
+#ifndef NO_IPV6
+	if (sa1->sa_family == AF_INET6)
+		return memcmp(&((struct sockaddr_in6 *)s1)->sin6_addr,
+		    &((struct sockaddr_in6 *)s2)->sin6_addr,
+		    sizeof(struct in6_addr));
+#endif
+	return 0;
+}
 
-	if (pid) {
-		unsigned idx;
+static int max_connections = 32;
 
-		close(incoming);
-		if (pid < 0)
-			return;
+static unsigned int live_children;
 
-		idx = children_spawned % MAX_CHILDREN;
-		children_spawned++;
-		add_child(idx, pid, addr, addrlen);
+static struct child {
+	struct child *next;
+	struct child_process cld;
+	struct sockaddr_storage address;
+} *firstborn;
 
-		check_max_connections();
+static void add_child(struct child_process *cld, struct sockaddr *addr, socklen_t addrlen)
+{
+	struct child *newborn, **cradle;
+
+	newborn = xcalloc(1, sizeof(*newborn));
+	live_children++;
+	memcpy(&newborn->cld, cld, sizeof(*cld));
+	memcpy(&newborn->address, addr, addrlen);
+	for (cradle = &firstborn; *cradle; cradle = &(*cradle)->next)
+		if (!addrcmp(&(*cradle)->address, &newborn->address))
+			break;
+	newborn->next = *cradle;
+	*cradle = newborn;
+}
+
+/*
+ * This gets called if the number of connections grows
+ * past "max_connections".
+ *
+ * We kill the newest connection from a duplicate IP.
+ */
+static void kill_some_child(void)
+{
+	const struct child *blanket, *next;
+
+	if (!(blanket = firstborn))
 		return;
-	}
 
-	dup2(incoming, 0);
-	dup2(incoming, 1);
-	close(incoming);
+	for (; (next = blanket->next); blanket = next)
+		if (!addrcmp(&blanket->address, &next->address)) {
+			kill(blanket->cld.pid, SIGTERM);
+			break;
+		}
+}
+
+static void check_dead_children(void)
+{
+	int status;
+	pid_t pid;
+
+	struct child **cradle, *blanket;
+	for (cradle = &firstborn; (blanket = *cradle);)
+		if ((pid = waitpid(blanket->cld.pid, &status, WNOHANG)) > 1) {
+			const char *dead = "";
+			if (status)
+				dead = " (with error)";
+			loginfo("[%"PRIuMAX"] Disconnected%s", (uintmax_t)pid, dead);
+
+			/* remove the child */
+			*cradle = blanket->next;
+			live_children--;
+			free(blanket);
+		} else
+			cradle = &blanket->next;
+}
+
+static char **cld_argv;
+static void handle(int incoming, struct sockaddr *addr, socklen_t addrlen)
+{
+	struct child_process cld = { NULL };
+	char addrbuf[300] = "REMOTE_ADDR=", portbuf[300];
+	char *env[] = { addrbuf, portbuf, NULL };
+
+	if (max_connections && live_children >= max_connections) {
+		kill_some_child();
+		sleep(1);  /* give it some time to die */
+		check_dead_children();
+		if (live_children >= max_connections) {
+			close(incoming);
+			logerror("Too many children, dropping connection");
+			return;
+		}
+	}
 
 	if (addr->sa_family == AF_INET) {
 		struct sockaddr_in *sin_addr = (void *) addr;
-		inet_ntop(AF_INET, &sin_addr->sin_addr, addrbuf, sizeof(addrbuf));
-		port = sin_addr->sin_port;
-
+		inet_ntop(addr->sa_family, &sin_addr->sin_addr, addrbuf + 12,
+		    sizeof(addrbuf) - 12);
+		snprintf(portbuf, sizeof(portbuf), "REMOTE_PORT=%d",
+		    ntohs(sin_addr->sin_port));
 #ifndef NO_IPV6
-	} else if (addr->sa_family == AF_INET6) {
+	} else if (addr && addr->sa_family == AF_INET6) {
 		struct sockaddr_in6 *sin6_addr = (void *) addr;
 
-		char *buf = addrbuf;
+		char *buf = addrbuf + 12;
 		*buf++ = '['; *buf = '\0'; /* stpcpy() is cool */
-		inet_ntop(AF_INET6, &sin6_addr->sin6_addr, buf, sizeof(addrbuf) - 1);
+		inet_ntop(AF_INET6, &sin6_addr->sin6_addr, buf,
+		    sizeof(addrbuf) - 13);
 		strcat(buf, "]");
 
-		port = sin6_addr->sin6_port;
+		snprintf(portbuf, sizeof(portbuf), "REMOTE_PORT=%d",
+		    ntohs(sin6_addr->sin6_port));
 #endif
 	}
-	loginfo("Connection from %s:%d", addrbuf, port);
 
-	exit(execute());
+	cld.env = (const char **)env;
+	cld.argv = (const char **)cld_argv;
+	cld.in = incoming;
+	cld.out = dup(incoming);
+
+	if (start_command(&cld))
+		logerror("unable to fork");
+	else
+		add_child(&cld, addr, addrlen);
+	close(incoming);
 }
 
 static void child_handler(int signo)
 {
-	for (;;) {
-		int status;
-		pid_t pid = waitpid(-1, &status, WNOHANG);
-
-		if (pid > 0) {
-			unsigned reaped = children_reaped;
-			dead_child[reaped % MAX_CHILDREN] = pid;
-			children_reaped = reaped + 1;
-			/* XXX: Custom logging, since we don't wanna getpid() */
-			if (verbose) {
-				char *dead = "";
-				if (!WIFEXITED(status) || WEXITSTATUS(status) > 0)
-					dead = " (with error)";
-				if (log_syslog)
-					syslog(LOG_INFO, "[%d] Disconnected%s", pid, dead);
-				else
-					fprintf(stderr, "[%d] Disconnected%s\n", pid, dead);
-			}
-			continue;
-		}
-		break;
-	}
+	/*
+	 * Otherwise empty handler because systemcalls will get interrupted
+	 * upon signal receipt
+	 * SysV needs the handler to be rearmed
+	 */
+	signal(SIGCHLD, child_handler);
 }
 
 static int set_reuse_addr(int sockfd)
@@ -489,37 +728,44 @@ static int set_reuse_addr(int sockfd)
 			  &on, sizeof(on));
 }
 
+struct socketlist {
+	int *list;
+	size_t nr;
+	size_t alloc;
+};
+
 #ifndef NO_IPV6
 
-static int socksetup(int port, int **socklist_p)
+static int setup_named_sock(char *listen_addr, int listen_port, struct socketlist *socklist)
 {
-	int socknum = 0, *socklist = NULL;
+	int socknum = 0;
 	int maxfd = -1;
 	char pbuf[NI_MAXSERV];
-
 	struct addrinfo hints, *ai0, *ai;
 	int gai;
+	long flags;
 
-	sprintf(pbuf, "%d", port);
+	sprintf(pbuf, "%d", listen_port);
 	memset(&hints, 0, sizeof(hints));
 	hints.ai_family = AF_UNSPEC;
 	hints.ai_socktype = SOCK_STREAM;
 	hints.ai_protocol = IPPROTO_TCP;
 	hints.ai_flags = AI_PASSIVE;
 
-	gai = getaddrinfo(NULL, pbuf, &hints, &ai0);
-	if (gai)
-		die("getaddrinfo() failed: %s\n", gai_strerror(gai));
+	gai = getaddrinfo(listen_addr, pbuf, &hints, &ai0);
+	if (gai) {
+		logerror("getaddrinfo() for %s failed: %s", listen_addr, gai_strerror(gai));
+		return 0;
+	}
 
 	for (ai = ai0; ai; ai = ai->ai_next) {
 		int sockfd;
-		int *newlist;
 
 		sockfd = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
 		if (sockfd < 0)
 			continue;
 		if (sockfd >= FD_SETSIZE) {
-			error("too large socket descriptor.");
+			logerror("Socket descriptor too large");
 			close(sockfd);
 			continue;
 		}
@@ -535,7 +781,7 @@ static int socksetup(int port, int **socklist_p)
 
 		if (set_reuse_addr(sockfd)) {
 			close(sockfd);
-			return 0;	/* not fatal */
+			continue;
 		}
 
 		if (bind(sockfd, ai->ai_addr, ai->ai_addrlen) < 0) {
@@ -547,12 +793,13 @@ static int socksetup(int port, int **socklist_p)
 			continue;	/* not fatal */
 		}
 
-		newlist = realloc(socklist, sizeof(int) * (socknum + 1));
-		if (!newlist)
-			die("memory allocation failed: %s", strerror(errno));
+		flags = fcntl(sockfd, F_GETFD, 0);
+		if (flags >= 0)
+			fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
 
-		socklist = newlist;
-		socklist[socknum++] = sockfd;
+		ALLOC_GROW(socklist->list, socklist->nr + 1, socklist->alloc);
+		socklist->list[socklist->nr++] = sockfd;
+		socknum++;
 
 		if (maxfd < sockfd)
 			maxfd = sockfd;
@@ -560,26 +807,33 @@ static int socksetup(int port, int **socklist_p)
 
 	freeaddrinfo(ai0);
 
-	*socklist_p = socklist;
 	return socknum;
 }
 
 #else /* NO_IPV6 */
 
-static int socksetup(int port, int **socklist_p)
+static int setup_named_sock(char *listen_addr, int listen_port, struct socketlist *socklist)
 {
 	struct sockaddr_in sin;
 	int sockfd;
+	long flags;
+
+	memset(&sin, 0, sizeof sin);
+	sin.sin_family = AF_INET;
+	sin.sin_port = htons(listen_port);
+
+	if (listen_addr) {
+		/* Well, host better be an IP address here. */
+		if (inet_pton(AF_INET, listen_addr, &sin.sin_addr.s_addr) <= 0)
+			return 0;
+	} else {
+		sin.sin_addr.s_addr = htonl(INADDR_ANY);
+	}
 
 	sockfd = socket(AF_INET, SOCK_STREAM, 0);
 	if (sockfd < 0)
 		return 0;
 
-	memset(&sin, 0, sizeof sin);
-	sin.sin_family = AF_INET;
-	sin.sin_addr.s_addr = htonl(INADDR_ANY);
-	sin.sin_port = htons(port);
-
 	if (set_reuse_addr(sockfd)) {
 		close(sockfd);
 		return 0;
@@ -595,22 +849,43 @@ static int socksetup(int port, int **socklist_p)
 		return 0;
 	}
 
-	*socklist_p = xmalloc(sizeof(int));
-	**socklist_p = sockfd;
+	flags = fcntl(sockfd, F_GETFD, 0);
+	if (flags >= 0)
+		fcntl(sockfd, F_SETFD, flags | FD_CLOEXEC);
+
+	ALLOC_GROW(socklist->list, socklist->nr + 1, socklist->alloc);
+	socklist->list[socklist->nr++] = sockfd;
 	return 1;
 }
 
 #endif
 
-static int service_loop(int socknum, int *socklist)
+static void socksetup(struct string_list *listen_addr, int listen_port, struct socketlist *socklist)
+{
+	if (!listen_addr->nr)
+		setup_named_sock(NULL, listen_port, socklist);
+	else {
+		int i, socknum;
+		for (i = 0; i < listen_addr->nr; i++) {
+			socknum = setup_named_sock(listen_addr->items[i].string,
+						   listen_port, socklist);
+
+			if (socknum == 0)
+				logerror("unable to allocate any listen sockets for host %s on port %u",
+					 listen_addr->items[i].string, listen_port);
+		}
+	}
+}
+
+static int service_loop(struct socketlist *socklist)
 {
 	struct pollfd *pfd;
 	int i;
 
-	pfd = xcalloc(socknum, sizeof(struct pollfd));
+	pfd = xcalloc(socklist->nr, sizeof(struct pollfd));
 
-	for (i = 0; i < socknum; i++) {
-		pfd[i].fd = socklist[i];
+	for (i = 0; i < socklist->nr; i++) {
+		pfd[i].fd = socklist->list[i];
 		pfd[i].events = POLLIN;
 	}
 
@@ -619,20 +894,28 @@ static int service_loop(int socknum, int *socklist)
 	for (;;) {
 		int i;
 
-		if (poll(pfd, socknum, -1) < 0) {
+		check_dead_children();
+
+		if (poll(pfd, socklist->nr, -1) < 0) {
 			if (errno != EINTR) {
-				error("poll failed, resuming: %s",
+				logerror("Poll failed, resuming: %s",
 				      strerror(errno));
 				sleep(1);
 			}
 			continue;
 		}
 
-		for (i = 0; i < socknum; i++) {
+		for (i = 0; i < socklist->nr; i++) {
 			if (pfd[i].revents & POLLIN) {
-				struct sockaddr_storage ss;
-				unsigned int sslen = sizeof(ss);
-				int incoming = accept(pfd[i].fd, (struct sockaddr *)&ss, &sslen);
+				union {
+					struct sockaddr sa;
+					struct sockaddr_in sai;
+#ifndef NO_IPV6
+					struct sockaddr_in6 sai6;
+#endif
+				} ss;
+				socklen_t sslen = sizeof(ss);
+				int incoming = accept(pfd[i].fd, &ss.sa, &sslen);
 				if (incoming < 0) {
 					switch (errno) {
 					case EAGAIN:
@@ -640,44 +923,158 @@ static int service_loop(int socknum, int *socklist)
 					case ECONNABORTED:
 						continue;
 					default:
-						die("accept returned %s", strerror(errno));
+						die_errno("accept returned");
 					}
 				}
-				handle(incoming, (struct sockaddr *)&ss, sslen);
+				handle(incoming, &ss.sa, sslen);
 			}
 		}
 	}
 }
 
-static int serve(int port)
+/* 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;
+
+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)
+{
+	die("--user not supported on this platform");
+}
+
+#else
+
+struct credentials {
+	struct passwd *pass;
+	gid_t gid;
+};
+
+static void drop_privileges(struct credentials *cred)
+{
+	if (cred && (initgroups(cred->pass->pw_name, cred->gid) ||
+	    setgid (cred->gid) || setuid(cred->pass->pw_uid)))
+		die("cannot drop privileges");
+}
+
+static struct credentials *prepare_credentials(const char *user_name,
+    const char *group_name)
+{
+	static struct credentials c;
+
+	c.pass = getpwnam(user_name);
+	if (!c.pass)
+		die("user not found - %s", user_name);
+
+	if (!group_name)
+		c.gid = c.pass->pw_gid;
+	else {
+		struct group *group = getgrnam(group_name);
+		if (!group)
+			die("group not found - %s", group_name);
+
+		c.gid = group->gr_gid;
+	}
+
+	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)
 {
-	int socknum, *socklist;
+	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);
+}
 
-	socknum = socksetup(port, &socklist);
-	if (socknum == 0)
-		die("unable to allocate any listen sockets on port %u", port);
+static int serve(struct string_list *listen_addr, int listen_port,
+    struct credentials *cred)
+{
+	struct socketlist socklist = { NULL, 0, 0 };
 
-	return service_loop(socknum, socklist);
+	socksetup(listen_addr, listen_port, &socklist);
+	if (socklist.nr == 0)
+		die("unable to allocate any listen sockets on port %u",
+		    listen_port);
+
+	drop_privileges(cred);
+
+	return service_loop(&socklist);
 }
 
 int main(int argc, char **argv)
 {
-	int port = DEFAULT_GIT_PORT;
-	int inetd_mode = 0;
+	int listen_port = 0;
+	struct string_list listen_addr = STRING_LIST_INIT_NODUP;
+	int serve_mode = 0, inetd_mode = 0;
+	const char *pid_file = NULL, *user_name = NULL, *group_name = NULL;
+	int detach = 0;
+	struct credentials *cred = NULL;
 	int i;
 
+	git_extract_argv0_path(argv[0]);
+
 	for (i = 1; i < argc; i++) {
 		char *arg = argv[i];
 
-		if (!strncmp(arg, "--port=", 7)) {
+		if (!prefixcmp(arg, "--listen=")) {
+			string_list_append(&listen_addr, xstrdup_tolower(arg + 9));
+			continue;
+		}
+		if (!prefixcmp(arg, "--port=")) {
 			char *end;
 			unsigned long n;
 			n = strtoul(arg+7, &end, 0);
 			if (arg[7] && !*end) {
-				port = n;
+				listen_port = n;
 				continue;
 			}
 		}
+		if (!strcmp(arg, "--serve")) {
+			serve_mode = 1;
+			continue;
+		}
 		if (!strcmp(arg, "--inetd")) {
 			inetd_mode = 1;
 			log_syslog = 1;
@@ -695,22 +1092,36 @@ int main(int argc, char **argv)
 			export_all_trees = 1;
 			continue;
 		}
-		if (!strncmp(arg, "--timeout=", 10)) {
+		if (!prefixcmp(arg, "--timeout=")) {
 			timeout = atoi(arg+10);
 			continue;
 		}
-		if (!strncmp(arg, "--init-timeout=", 15)) {
+		if (!prefixcmp(arg, "--init-timeout=")) {
 			init_timeout = atoi(arg+15);
 			continue;
 		}
+		if (!prefixcmp(arg, "--max-connections=")) {
+			max_connections = atoi(arg+18);
+			if (max_connections < 0)
+				max_connections = 0;	        /* unlimited */
+			continue;
+		}
 		if (!strcmp(arg, "--strict-paths")) {
 			strict_paths = 1;
 			continue;
 		}
-		if (!strncmp(arg, "--base-path=", 12)) {
+		if (!prefixcmp(arg, "--base-path=")) {
 			base_path = arg+12;
 			continue;
 		}
+		if (!strcmp(arg, "--base-path-relaxed")) {
+			base_path_relaxed = 1;
+			continue;
+		}
+		if (!prefixcmp(arg, "--interpolated-path=")) {
+			interpolated_path = arg+20;
+			continue;
+		}
 		if (!strcmp(arg, "--reuseaddr")) {
 			reuseaddr = 1;
 			continue;
@@ -719,10 +1130,43 @@ int main(int argc, char **argv)
 			user_path = "";
 			continue;
 		}
-		if (!strncmp(arg, "--user-path=", 12)) {
+		if (!prefixcmp(arg, "--user-path=")) {
 			user_path = arg + 12;
 			continue;
 		}
+		if (!prefixcmp(arg, "--pid-file=")) {
+			pid_file = arg + 11;
+			continue;
+		}
+		if (!strcmp(arg, "--detach")) {
+			detach = 1;
+			log_syslog = 1;
+			continue;
+		}
+		if (!prefixcmp(arg, "--user=")) {
+			user_name = arg + 7;
+			continue;
+		}
+		if (!prefixcmp(arg, "--group=")) {
+			group_name = arg + 8;
+			continue;
+		}
+		if (!prefixcmp(arg, "--enable=")) {
+			enable_service(arg + 9, 1);
+			continue;
+		}
+		if (!prefixcmp(arg, "--disable=")) {
+			enable_service(arg + 10, 0);
+			continue;
+		}
+		if (!prefixcmp(arg, "--allow-override=")) {
+			make_service_overridable(arg + 17, 1);
+			continue;
+		}
+		if (!prefixcmp(arg, "--forbid-override=")) {
+			make_service_overridable(arg + 18, 0);
+			continue;
+		}
 		if (!strcmp(arg, "--")) {
 			ok_paths = &argv[i+1];
 			break;
@@ -734,21 +1178,59 @@ int main(int argc, char **argv)
 		usage(daemon_usage);
 	}
 
-	if (log_syslog)
-		openlog("git-daemon", 0, LOG_DAEMON);
+	if (log_syslog) {
+		openlog("git-daemon", LOG_PID, LOG_DAEMON);
+		set_die_routine(daemon_die);
+	} else
+		/* avoid splitting a message in the middle */
+		setvbuf(stderr, NULL, _IOFBF, 4096);
 
-	if (strict_paths && (!ok_paths || !*ok_paths)) {
-		if (!inetd_mode)
-			die("git-daemon: option --strict-paths requires a whitelist");
+	if (inetd_mode && (detach || group_name || user_name))
+		die("--detach, --user and --group are incompatible with --inetd");
 
-		logerror("option --strict-paths requires a whitelist");
-		exit (1);
-	}
+	if (inetd_mode && (listen_port || (listen_addr.nr > 0)))
+		die("--listen= and --port= are incompatible with --inetd");
+	else if (listen_port == 0)
+		listen_port = DEFAULT_GIT_PORT;
+
+	if (group_name && !user_name)
+		die("--group supplied without --user");
+
+	if (user_name)
+		cred = prepare_credentials(user_name, group_name);
+
+	if (strict_paths && (!ok_paths || !*ok_paths))
+		die("option --strict-paths requires a whitelist");
+
+	if (base_path && !is_directory(base_path))
+		die("base-path '%s' does not exist or is not a directory",
+		    base_path);
 
 	if (inetd_mode) {
-		fclose(stderr); //FIXME: workaround
+		if (!freopen("/dev/null", "w", stderr))
+			die_errno("failed to redirect stderr to /dev/null");
+	}
+
+	if (inetd_mode || serve_mode)
 		return execute();
+
+	if (detach) {
+		daemonize();
+		loginfo("Ready to rumble");
 	}
+	else
+		sanitize_stdfds();
+
+	if (pid_file)
+		store_pid(pid_file);
+
+	/* prepare argv for serving-processes */
+	cld_argv = xmalloc(sizeof (char *) * (argc + 2));
+	cld_argv[0] = argv[0];	/* git-daemon */
+	cld_argv[1] = "--serve";
+	for (i = 1; i < argc; ++i)
+		cld_argv[i+1] = argv[i];
+	cld_argv[argc+1] = NULL;
 
-	return serve(port);
+	return serve(&listen_addr, listen_port, cred);
 }