clone: the given repository dir should be relative to $PWD
[gitweb.git] / daemon.c
index fb3f25c48665596f41ebcee66037bdd1be2dd30a..ad8492873ea1db63d56c24bec6174c4682105433 100644 (file)
--- a/daemon.c
+++ b/daemon.c
-#include "cache.h"
-#include "pkt-line.h"
 #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 <pwd.h>
+#include <grp.h>
+#include <limits.h>
+#include "pkt-line.h"
+#include "cache.h"
+#include "exec_cmd.h"
+#include "interpolate.h"
+
+#ifndef HOST_NAME_MAX
+#define HOST_NAME_MAX 256
+#endif
+
+static int log_syslog;
+static int verbose;
+static int reuseaddr;
+
+static const char daemon_usage[] =
+"git-daemon [--verbose] [--syslog] [--export-all]\n"
+"           [--timeout=n] [--init-timeout=n] [--strict-paths]\n"
+"           [--base-path=path] [--user-path | --user-path=path]\n"
+"           [--interpolated-path=path]\n"
+"           [--reuseaddr] [--detach] [--pid-file=file]\n"
+"           [--[enable|disable|allow-override|forbid-override]=service]\n"
+"           [--inetd | [--listen=host_or_ipaddr] [--port=n]\n"
+"                      [--user=user [--group=group]]\n"
+"           [directory...]";
+
+/* List of acceptable pathname prefixes */
+static char **ok_paths;
+static int strict_paths;
+
+/* If this is set, git-daemon-export-ok is not required */
+static int export_all_trees;
+
+/* Take all paths relative to this one if non-NULL */
+static char *base_path;
+static char *interpolated_path;
+
+/* 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 const char *user_path;
+
+/* Timeout, and initial timeout */
+static unsigned int timeout;
+static unsigned int init_timeout;
+
+/*
+ * Static table for now.  Ugh.
+ * Feel free to make dynamic as needed.
+ */
+#define INTERP_SLOT_HOST       (0)
+#define INTERP_SLOT_CANON_HOST (1)
+#define INTERP_SLOT_IP         (2)
+#define INTERP_SLOT_PORT       (3)
+#define INTERP_SLOT_DIR                (4)
+#define INTERP_SLOT_PERCENT    (5)
+
+static struct interp interp_table[] = {
+       { "%H", 0},
+       { "%CH", 0},
+       { "%IP", 0},
+       { "%P", 0},
+       { "%D", 0},
+       { "%%", 0},
+};
+
+
+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) {
+               syslog(priority, "%s", buf);
+               return;
+       }
+
+       /* 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);
+}
+
+static void logerror(const char *err, ...)
+{
+       va_list params;
+       va_start(params, err);
+       logreport(LOG_ERR, err, params);
+       va_end(params);
+}
+
+static void loginfo(const char *err, ...)
+{
+       va_list params;
+       if (!verbose)
+               return;
+       va_start(params, err);
+       logreport(LOG_INFO, err, params);
+       va_end(params);
+}
+
+static void NORETURN daemon_die(const char *err, va_list params)
+{
+       logreport(LOG_ERR, err, params);
+       exit(1);
+}
+
+static int avoid_alias(char *p)
+{
+       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;
+               }
+       }
+}
+
+static char *path_ok(struct interp *itable)
+{
+       static char rpath[PATH_MAX];
+       static char interp_path[PATH_MAX];
+       char *path;
+       char *dir;
+
+       dir = itable[INTERP_SLOT_DIR].value;
+
+       if (avoid_alias(dir)) {
+               logerror("'%s': aliased", dir);
+               return NULL;
+       }
+
+       if (*dir == '~') {
+               if (!user_path) {
+                       logerror("'%s': User-path not allowed", dir);
+                       return NULL;
+               }
+               if (*user_path) {
+                       /* Got either "~alice" or "~alice/foo";
+                        * rewrite them to "~alice/%s" or
+                        * "~alice/%s/foo".
+                        */
+                       int namlen, restlen = strlen(dir);
+                       char *slash = strchr(dir, '/');
+                       if (!slash)
+                               slash = dir + restlen;
+                       namlen = slash - dir;
+                       restlen -= namlen;
+                       loginfo("userpath <%s>, request <%s>, namlen %d, restlen %d, slash <%s>", user_path, dir, namlen, restlen, slash);
+                       snprintf(rpath, PATH_MAX, "%.*s/%s%.*s",
+                                namlen, dir, user_path, restlen, slash);
+                       dir = rpath;
+               }
+       }
+       else if (interpolated_path && saw_extended_args) {
+               if (*dir != '/') {
+                       /* Allow only absolute */
+                       logerror("'%s': Non-absolute path denied (interpolated-path active)", dir);
+                       return NULL;
+               }
+
+               interpolate(interp_path, PATH_MAX, interpolated_path,
+                           interp_table, ARRAY_SIZE(interp_table));
+               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;
+               }
+               snprintf(rpath, PATH_MAX, "%s%s", base_path, dir);
+               dir = rpath;
+       }
+
+       path = enter_repo(dir, strict_paths);
+
+       if (!path) {
+               logerror("'%s': unable to chdir or not a git archive", dir);
+               return NULL;
+       }
+
+       if ( ok_paths && *ok_paths ) {
+               char **pp;
+               int pathlen = strlen(path);
 
-static const char daemon_usage[] = "git-daemon [--inetd | --port=n]";
+               /* The validation is done on the paths after enter_repo
+                * 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.
+                * Do not say /pub/.
+                */
+               for ( pp = ok_paths ; *pp ; pp++ ) {
+                       int len = strlen(*pp);
+                       if (len <= pathlen &&
+                           !memcmp(*pp, path, len) &&
+                           (path[len] == '\0' ||
+                            (!strict_paths && path[len] == '/')))
+                               return path;
+               }
+       }
+       else {
+               /* be backwards compatible */
+               if (!strict_paths)
+                       return path;
+       }
+
+       logerror("'%s': not in whitelist", path);
+       return NULL;            /* Fallthrough. Deny by default */
+}
 
-static int upload(char *dir, int dirlen)
+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)
 {
-       if (chdir(dir) < 0)
+       if (!strncmp(var, "daemon.", 7) &&
+           !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(struct interp *itable, struct daemon_service *service)
+{
+       const char *path;
+       int enabled = service->enabled;
+
+       loginfo("Request %s for '%s'",
+               service->name,
+               itable[INTERP_SLOT_DIR].value);
+
+       if (!enabled && !service->overridable) {
+               logerror("'%s': service not enabled.", service->name);
+               errno = EACCES;
+               return -1;
+       }
+
+       if (!(path = path_ok(itable)))
                return -1;
-       chdir(".git");
 
        /*
         * Security on the cheap.
         *
-        * We want a readable HEAD, usable "objects" directory, and 
+        * We want a readable HEAD, usable "objects" directory, and
         * a "git-daemon-export-ok" flag that says that the other side
         * is ok with us doing this.
+        *
+        * path_ok() uses enter_repo() and does whitelist checking.
+        * We only need to make sure the repository is exported.
         */
-       if (access("git-daemon-export-ok", F_OK) ||
-           access("objects/00", X_OK) ||
-           access("HEAD", R_OK))
+
+       if (!export_all_trees && access("git-daemon-export-ok", F_OK)) {
+               logerror("'%s': repository not exported.", path);
+               errno = EACCES;
                return -1;
+       }
+
+       if (service->overridable) {
+               service_looking_at = service;
+               service_enabled = -1;
+               git_config(git_daemon_config);
+               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
@@ -33,25 +361,220 @@ static int upload(char *dir, int dirlen)
         */
        signal(SIGTERM, SIG_IGN);
 
+       return service->fn();
+}
+
+static int upload_pack(void)
+{
+       /* Timeout as string */
+       char timeout_buf[64];
+
+       snprintf(timeout_buf, sizeof timeout_buf, "--timeout=%u", timeout);
+
        /* git-upload-pack only ever reads stuff, so this is safe */
-       execlp("git-upload-pack", "git-upload-pack", ".", NULL);
+       execl_git_cmd("upload-pack", "--strict", timeout_buf, ".", NULL);
+       return -1;
+}
+
+static int upload_archive(void)
+{
+       execl_git_cmd("upload-archive", ".", NULL);
        return -1;
 }
 
-static int execute(void)
+static struct daemon_service daemon_service[] = {
+       { "upload-archive", "uploadarch", upload_archive, 0, 1 },
+       { "upload-pack", "uploadpack", upload_pack, 1, 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;
+               }
+       }
+       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;
+               }
+       }
+       die("No such service %s", name);
+}
+
+/*
+ * Separate the "extra args" information as supplied by the client connection.
+ * Any resulting data is squirrelled away in the given interpolation table.
+ */
+static void parse_extra_args(struct interp *table, char *extra_args, int buflen)
+{
+       char *val;
+       int vallen;
+       char *end = extra_args + buflen;
+
+       while (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 = val;
+                               char *port = strrchr(host, ':');
+                               if (port) {
+                                       *port = 0;
+                                       port++;
+                                       interp_set_entry(table, INTERP_SLOT_PORT, port);
+                               }
+                               interp_set_entry(table, INTERP_SLOT_HOST, host);
+                       }
+
+                       /* On to the next one */
+                       extra_args = val + vallen;
+               }
+       }
+}
+
+void fill_in_extra_table_entries(struct interp *itable)
+{
+       char *hp;
+
+       /*
+        * Replace literal host with lowercase-ized hostname.
+        */
+       hp = interp_table[INTERP_SLOT_HOST].value;
+       for ( ; *hp; hp++)
+               *hp = tolower(*hp);
+
+       /*
+        * Locate canonical hostname and its IP address.
+        */
+#ifndef NO_IPV6
+       {
+               struct addrinfo hints;
+               struct addrinfo *ai, *ai0;
+               int gai;
+               static char addrbuf[HOST_NAME_MAX + 1];
+
+               memset(&hints, 0, sizeof(hints));
+               hints.ai_flags = AI_CANONNAME;
+
+               gai = getaddrinfo(interp_table[INTERP_SLOT_HOST].value, 0, &hints, &ai0);
+               if (!gai) {
+                       for (ai = ai0; ai; ai = ai->ai_next) {
+                               struct sockaddr_in *sin_addr = (void *)ai->ai_addr;
+
+                               inet_ntop(AF_INET, &sin_addr->sin_addr,
+                                         addrbuf, sizeof(addrbuf));
+                               interp_set_entry(interp_table,
+                                                INTERP_SLOT_CANON_HOST, ai->ai_canonname);
+                               interp_set_entry(interp_table,
+                                                INTERP_SLOT_IP, addrbuf);
+                               break;
+                       }
+                       freeaddrinfo(ai0);
+               }
+       }
+#else
+       {
+               struct hostent *hent;
+               struct sockaddr_in sa;
+               char **ap;
+               static char addrbuf[HOST_NAME_MAX + 1];
+
+               hent = gethostbyname(interp_table[INTERP_SLOT_HOST].value);
+
+               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));
+
+               interp_set_entry(interp_table, INTERP_SLOT_CANON_HOST, hent->h_name);
+               interp_set_entry(interp_table, INTERP_SLOT_IP, addrbuf);
+       }
+#endif
+}
+
+
+static int execute(struct sockaddr *addr)
 {
        static char line[1000];
-       int len;
+       int pktlen, len, i;
 
-       len = packet_read_line(0, line, sizeof(line));
+       if (addr) {
+               char addrbuf[256] = "";
+               int port = -1;
 
+               if (addr->sa_family == AF_INET) {
+                       struct sockaddr_in *sin_addr = (void *) addr;
+                       inet_ntop(addr->sa_family, &sin_addr->sin_addr, addrbuf, sizeof(addrbuf));
+                       port = sin_addr->sin_port;
+#ifndef NO_IPV6
+               } else if (addr && addr->sa_family == AF_INET6) {
+                       struct sockaddr_in6 *sin6_addr = (void *) addr;
+
+                       char *buf = addrbuf;
+                       *buf++ = '['; *buf = '\0'; /* stpcpy() is cool */
+                       inet_ntop(AF_INET6, &sin6_addr->sin6_addr, buf, sizeof(addrbuf) - 1);
+                       strcat(buf, "]");
+
+                       port = sin6_addr->sin6_port;
+#endif
+               }
+               loginfo("Connection from %s:%d", addrbuf, port);
+       }
+
+       alarm(init_timeout ? init_timeout : timeout);
+       pktlen = packet_read_line(0, line, sizeof(line));
+       alarm(0);
+
+       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;
 
-       if (!strncmp("git-upload-pack /", line, 17))
-               return upload(line + 16, len - 16);
+       /*
+        * Initialize the path interpolation table for this connection.
+        */
+       interp_clear_table(interp_table, ARRAY_SIZE(interp_table));
+       interp_set_entry(interp_table, INTERP_SLOT_PERCENT, "%");
+
+       if (len != pktlen) {
+           parse_extra_args(interp_table, line + len + 1, pktlen - len - 1);
+           fill_in_extra_table_entries(interp_table);
+       }
+
+       for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
+               struct daemon_service *s = &(daemon_service[i]);
+               int namelen = strlen(s->name);
+               if (!strncmp("git-", line, 4) &&
+                   !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.
+                        */
+                       interp_set_entry(interp_table,
+                                        INTERP_SLOT_DIR, line + namelen + 5);
+                       return run_service(interp_table, s);
+               }
+       }
 
-       fprintf(stderr, "got bad connection '%s'\n", line);
+       logerror("Protocol error: '%s'", line);
        return -1;
 }
 
@@ -71,20 +594,20 @@ static int execute(void)
 static int max_connections = 25;
 
 /* These are updated by the signal handler */
-static volatile unsigned int children_reaped = 0;
+static volatile unsigned int children_reaped;
 static pid_t dead_child[MAX_CHILDREN];
 
 /* These are updated by the main loop */
-static unsigned int children_spawned = 0;
-static unsigned int children_deleted = 0;
+static unsigned int children_spawned;
+static unsigned int children_deleted;
 
 static struct child {
        pid_t pid;
-       socklen_t addrlen;
+       int addrlen;
        struct sockaddr_storage address;
 } live_child[MAX_CHILDREN];
 
-static void add_child(int idx, pid_t pid, struct sockaddr *addr, socklen_t addrlen)
+static void add_child(int idx, pid_t pid, struct sockaddr *addr, int addrlen)
 {
        live_child[idx].pid = pid;
        live_child[idx].addrlen = addrlen;
@@ -178,7 +701,7 @@ static void check_max_connections(void)
        }
 }
 
-static void handle(int incoming, struct sockaddr *addr, socklen_t addrlen)
+static void handle(int incoming, struct sockaddr *addr, int addrlen)
 {
        pid_t pid = fork();
 
@@ -200,51 +723,69 @@ static void handle(int incoming, struct sockaddr *addr, socklen_t addrlen)
        dup2(incoming, 0);
        dup2(incoming, 1);
        close(incoming);
-       exit(execute());
+
+       exit(execute(addr));
 }
 
 static void child_handler(int signo)
 {
        for (;;) {
-               pid_t pid = waitpid(-1, NULL, WNOHANG);
+               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) {
+                               const 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;
        }
 }
 
-static int serve(int port)
+static int set_reuse_addr(int sockfd)
+{
+       int on = 1;
+
+       if (!reuseaddr)
+               return 0;
+       return setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR,
+                         &on, sizeof(on));
+}
+
+#ifndef NO_IPV6
+
+static int socksetup(char *listen_addr, int listen_port, int **socklist_p)
 {
-       struct addrinfo hints, *ai0, *ai;
-       int gai;
        int socknum = 0, *socklist = NULL;
        int maxfd = -1;
-       fd_set fds_init, fds;
        char pbuf[NI_MAXSERV];
+       struct addrinfo hints, *ai0, *ai;
+       int gai;
 
-       signal(SIGCHLD, child_handler);
-
-       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);
+       gai = getaddrinfo(listen_addr, pbuf, &hints, &ai0);
        if (gai)
                die("getaddrinfo() failed: %s\n", gai_strerror(gai));
 
-       FD_ZERO(&fds_init);
-
        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)
@@ -264,6 +805,11 @@ static int serve(int port)
                }
 #endif
 
+               if (set_reuse_addr(sockfd)) {
+                       close(sockfd);
+                       continue;
+               }
+
                if (bind(sockfd, ai->ai_addr, ai->ai_addrlen) < 0) {
                        close(sockfd);
                        continue;       /* not fatal */
@@ -273,30 +819,84 @@ static int serve(int port)
                        continue;       /* not fatal */
                }
 
-               newlist = realloc(socklist, sizeof(int) * (socknum + 1));
-               if (!newlist)
-                       die("memory allocation failed: %s", strerror(errno));
-
-               socklist = newlist;
+               socklist = xrealloc(socklist, sizeof(int) * (socknum + 1));
                socklist[socknum++] = sockfd;
 
-               FD_SET(sockfd, &fds_init);
                if (maxfd < sockfd)
                        maxfd = sockfd;
        }
 
        freeaddrinfo(ai0);
 
-       if (socknum == 0)
-               die("unable to allocate any listen sockets on port %u", port);
+       *socklist_p = socklist;
+       return socknum;
+}
+
+#else /* NO_IPV6 */
+
+static int socksetup(char *listen_addr, int listen_port, int **socklist_p)
+{
+       struct sockaddr_in sin;
+       int sockfd;
+
+       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;
+
+       if (set_reuse_addr(sockfd)) {
+               close(sockfd);
+               return 0;
+       }
+
+       if ( bind(sockfd, (struct sockaddr *)&sin, sizeof sin) < 0 ) {
+               close(sockfd);
+               return 0;
+       }
+
+       if (listen(sockfd, 5) < 0) {
+               close(sockfd);
+               return 0;
+       }
+
+       *socklist_p = xmalloc(sizeof(int));
+       **socklist_p = sockfd;
+       return 1;
+}
+
+#endif
+
+static int service_loop(int socknum, int *socklist)
+{
+       struct pollfd *pfd;
+       int i;
+
+       pfd = xcalloc(socknum, sizeof(struct pollfd));
+
+       for (i = 0; i < socknum; i++) {
+               pfd[i].fd = socklist[i];
+               pfd[i].events = POLLIN;
+       }
+
+       signal(SIGCHLD, child_handler);
 
        for (;;) {
                int i;
-               fds = fds_init;
-               
-               if (select(maxfd + 1, &fds, NULL, NULL, NULL) < 0) {
+
+               if (poll(pfd, socknum, -1) < 0) {
                        if (errno != EINTR) {
-                               error("select failed, resuming: %s",
+                               error("poll failed, resuming: %s",
                                      strerror(errno));
                                sleep(1);
                        }
@@ -304,12 +904,10 @@ static int serve(int port)
                }
 
                for (i = 0; i < socknum; i++) {
-                       int sockfd = socklist[i];
-
-                       if (FD_ISSET(sockfd, &fds)) {
+                       if (pfd[i].revents & POLLIN) {
                                struct sockaddr_storage ss;
-                               socklen_t sslen = sizeof(ss);
-                               int incoming = accept(sockfd, (struct sockaddr *)&ss, &sslen);
+                               unsigned int sslen = sizeof(ss);
+                               int incoming = accept(pfd[i].fd, (struct sockaddr *)&ss, &sslen);
                                if (incoming < 0) {
                                        switch (errno) {
                                        case EAGAIN:
@@ -326,35 +924,247 @@ 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("open /dev/null or dup failed: %s", strerror(errno));
+       if (fd > 2)
+               close(fd);
+}
+
+static void daemonize(void)
+{
+       switch (fork()) {
+               case 0:
+                       break;
+               case -1:
+                       die("fork failed: %s", strerror(errno));
+               default:
+                       exit(0);
+       }
+       if (setsid() == -1)
+               die("setsid failed: %s", strerror(errno));
+       close(0);
+       close(1);
+       close(2);
+       sanitize_stdfds();
+}
+
+static void store_pid(const char *path)
+{
+       FILE *f = fopen(path, "w");
+       if (!f)
+               die("cannot open pid file %s: %s", path, strerror(errno));
+       fprintf(f, "%d\n", getpid());
+       fclose(f);
+}
+
+static int serve(char *listen_addr, int listen_port, struct passwd *pass, gid_t gid)
+{
+       int socknum, *socklist;
+
+       socknum = socksetup(listen_addr, listen_port, &socklist);
+       if (socknum == 0)
+               die("unable to allocate any listen sockets on host %s port %u",
+                   listen_addr, listen_port);
+
+       if (pass && gid &&
+           (initgroups(pass->pw_name, gid) || setgid (gid) ||
+            setuid(pass->pw_uid)))
+               die("cannot drop privileges");
+
+       return service_loop(socknum, socklist);
+}
+
 int main(int argc, char **argv)
 {
-       int port = DEFAULT_GIT_PORT;
+       int listen_port = 0;
+       char *listen_addr = NULL;
        int inetd_mode = 0;
+       const char *pid_file = NULL, *user_name = NULL, *group_name = NULL;
+       int detach = 0;
+       struct passwd *pass = NULL;
+       struct group *group;
+       gid_t gid = 0;
        int i;
 
+       /* Without this we cannot rely on waitpid() to tell
+        * what happened to our children.
+        */
+       signal(SIGCHLD, SIG_DFL);
+
        for (i = 1; i < argc; i++) {
                char *arg = argv[i];
 
+               if (!strncmp(arg, "--listen=", 9)) {
+                   char *p = arg + 9;
+                   char *ph = listen_addr = xmalloc(strlen(arg + 9) + 1);
+                   while (*p)
+                       *ph++ = tolower(*p++);
+                   *ph = 0;
+                   continue;
+               }
                if (!strncmp(arg, "--port=", 7)) {
                        char *end;
                        unsigned long n;
                        n = strtoul(arg+7, &end, 0);
                        if (arg[7] && !*end) {
-                               port = n;
+                               listen_port = n;
                                continue;
                        }
                }
-
                if (!strcmp(arg, "--inetd")) {
                        inetd_mode = 1;
+                       log_syslog = 1;
+                       continue;
+               }
+               if (!strcmp(arg, "--verbose")) {
+                       verbose = 1;
+                       continue;
+               }
+               if (!strcmp(arg, "--syslog")) {
+                       log_syslog = 1;
+                       continue;
+               }
+               if (!strcmp(arg, "--export-all")) {
+                       export_all_trees = 1;
+                       continue;
+               }
+               if (!strncmp(arg, "--timeout=", 10)) {
+                       timeout = atoi(arg+10);
+                       continue;
+               }
+               if (!strncmp(arg, "--init-timeout=", 15)) {
+                       init_timeout = atoi(arg+15);
+                       continue;
+               }
+               if (!strcmp(arg, "--strict-paths")) {
+                       strict_paths = 1;
+                       continue;
+               }
+               if (!strncmp(arg, "--base-path=", 12)) {
+                       base_path = arg+12;
+                       continue;
+               }
+               if (!strncmp(arg, "--interpolated-path=", 20)) {
+                       interpolated_path = arg+20;
+                       continue;
+               }
+               if (!strcmp(arg, "--reuseaddr")) {
+                       reuseaddr = 1;
+                       continue;
+               }
+               if (!strcmp(arg, "--user-path")) {
+                       user_path = "";
+                       continue;
+               }
+               if (!strncmp(arg, "--user-path=", 12)) {
+                       user_path = arg + 12;
                        continue;
                }
+               if (!strncmp(arg, "--pid-file=", 11)) {
+                       pid_file = arg + 11;
+                       continue;
+               }
+               if (!strcmp(arg, "--detach")) {
+                       detach = 1;
+                       log_syslog = 1;
+                       continue;
+               }
+               if (!strncmp(arg, "--user=", 7)) {
+                       user_name = arg + 7;
+                       continue;
+               }
+               if (!strncmp(arg, "--group=", 8)) {
+                       group_name = arg + 8;
+                       continue;
+               }
+               if (!strncmp(arg, "--enable=", 9)) {
+                       enable_service(arg + 9, 1);
+                       continue;
+               }
+               if (!strncmp(arg, "--disable=", 10)) {
+                       enable_service(arg + 10, 0);
+                       continue;
+               }
+               if (!strncmp(arg, "--allow-override=", 17)) {
+                       make_service_overridable(arg + 17, 1);
+                       continue;
+               }
+               if (!strncmp(arg, "--forbid-override=", 18)) {
+                       make_service_overridable(arg + 18, 0);
+                       continue;
+               }
+               if (!strcmp(arg, "--")) {
+                       ok_paths = &argv[i+1];
+                       break;
+               } else if (arg[0] != '-') {
+                       ok_paths = &argv[i];
+                       break;
+               }
 
                usage(daemon_usage);
        }
 
-       if (inetd_mode)
-               return execute();
+       if (inetd_mode && (group_name || user_name))
+               die("--user and --group are incompatible with --inetd");
+
+       if (inetd_mode && (listen_port || listen_addr))
+               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) {
+               pass = getpwnam(user_name);
+               if (!pass)
+                       die("user not found - %s", user_name);
+
+               if (!group_name)
+                       gid = pass->pw_gid;
+               else {
+                       group = getgrnam(group_name);
+                       if (!group)
+                               die("group not found - %s", group_name);
+
+                       gid = group->gr_gid;
+               }
+       }
+
+       if (log_syslog) {
+               openlog("git-daemon", 0, LOG_DAEMON);
+               set_die_routine(daemon_die);
+       }
+
+       if (strict_paths && (!ok_paths || !*ok_paths))
+               die("option --strict-paths requires a whitelist");
+
+       if (inetd_mode) {
+               struct sockaddr_storage ss;
+               struct sockaddr *peer = (struct sockaddr *)&ss;
+               socklen_t slen = sizeof(ss);
+
+               freopen("/dev/null", "w", stderr);
+
+               if (getpeername(0, peer, &slen))
+                       peer = NULL;
+
+               return execute(peer);
+       }
+
+       if (detach)
+               daemonize();
+       else
+               sanitize_stdfds();
+
+       if (pid_file)
+               store_pid(pid_file);
 
-       return serve(port);
+       return serve(listen_addr, listen_port, pass, gid);
 }