Imported Upstream version 2.25.1
[platform/upstream/git.git] / daemon.c
index ab21e66..fd669ed 100644 (file)
--- a/daemon.c
+++ b/daemon.c
@@ -1,23 +1,20 @@
 #include "cache.h"
+#include "config.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 enum log_destination {
+       LOG_DESTINATION_UNSET = -1,
+       LOG_DESTINATION_NONE = 0,
+       LOG_DESTINATION_STDERR = 1,
+       LOG_DESTINATION_SYSLOG = 2,
+} log_destination = LOG_DESTINATION_UNSET;
 static int verbose;
 static int reuseaddr;
 static int informative_errors;
@@ -30,25 +27,24 @@ static const char daemon_usage[] =
 "           [--interpolated-path=<path>]\n"
 "           [--reuseaddr] [--pid-file=<file>]\n"
 "           [--(enable|disable|allow-override|forbid-override)=<service>]\n"
+"           [--access-hook=<path>]\n"
 "           [--inetd | [--listen=<host_or_ipaddr>] [--port=<n>]\n"
 "                      [--detach] [--user=<user> [--group=<group>]]\n"
+"           [--log-destination=(stderr|syslog|none)]\n"
 "           [<directory>...]";
 
 /* List of acceptable pathname prefixes */
-static char **ok_paths;
+static const 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;
+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.
@@ -59,18 +55,39 @@ 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)
 {
-       if (log_syslog) {
+       switch (log_destination) {
+       case LOG_DESTINATION_SYSLOG: {
                char buf[1024];
                vsnprintf(buf, sizeof(buf), err, params);
                syslog(priority, "%s", buf);
-       } else {
+               break;
+       }
+       case LOG_DESTINATION_STDERR:
                /*
                 * Since stderr is set to buffered mode, the
                 * logging of different processes will not overlap
@@ -80,6 +97,11 @@ static void logreport(int priority, const char *err, va_list params)
                vfprintf(stderr, err, params);
                fputc('\n', stderr);
                fflush(stderr);
+               break;
+       case LOG_DESTINATION_NONE:
+               break;
+       case LOG_DESTINATION_UNSET:
+               BUG("log destination not initialized correctly");
        }
 }
 
@@ -109,12 +131,49 @@ 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];
+       size_t rlen;
        const char *path;
-       char *dir;
+       const char *dir;
 
        dir = directory;
 
@@ -134,27 +193,28 @@ 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;
                        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);
+                       rlen = snprintf(rpath, sizeof(rpath), "%.*s/%s%.*s",
+                                       namlen, dir, user_path, restlen, slash);
+                       if (rlen >= sizeof(rpath)) {
+                               logerror("user-path too large: %s", rpath);
+                               return NULL;
+                       }
                        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);
@@ -162,8 +222,16 @@ static const char *path_ok(char *directory)
                }
 
                strbuf_expand(&expanded_path, interpolated_path,
-                               strbuf_expand_dict_cb, &dict);
-               strlcpy(interp_path, expanded_path.buf, PATH_MAX);
+                             expand_path, &context);
+
+               rlen = strlcpy(interp_path, expanded_path.buf,
+                              sizeof(interp_path));
+               if (rlen >= sizeof(interp_path)) {
+                       logerror("interpolated path too large: %s",
+                                interp_path);
+                       return NULL;
+               }
+
                strbuf_release(&expanded_path);
                loginfo("Interpolated dir '%s'", interp_path);
 
@@ -175,7 +243,11 @@ static const char *path_ok(char *directory)
                        logerror("'%s': Non-absolute path denied (base-path active)", dir);
                        return NULL;
                }
-               snprintf(rpath, PATH_MAX, "%s%s", base_path, dir);
+               rlen = snprintf(rpath, sizeof(rpath), "%s%s", base_path, dir);
+               if (rlen >= sizeof(rpath)) {
+                       logerror("base-path too large: %s", rpath);
+                       return NULL;
+               }
                dir = rpath;
        }
 
@@ -195,7 +267,7 @@ static const char *path_ok(char *directory)
        }
 
        if ( ok_paths && *ok_paths ) {
-               char **pp;
+               const char **pp;
                int pathlen = strlen(path);
 
                /* The validation is done on the paths after enter_repo
@@ -224,7 +296,7 @@ static const char *path_ok(char *directory)
        return NULL;            /* Fallthrough. Deny by default */
 }
 
-typedef int (*daemon_service_fn)(void);
+typedef int (*daemon_service_fn)(const struct argv_array *env);
 struct daemon_service {
        const char *name;
        const char *config_name;
@@ -233,33 +305,83 @@ struct daemon_service {
        int overridable;
 };
 
-static struct daemon_service *service_looking_at;
-static int service_enabled;
+static int daemon_error(const char *dir, const char *msg)
+{
+       if (!informative_errors)
+               msg = "access denied or repository not exported";
+       packet_write_fmt(1, "ERR %s: %s", msg, dir);
+       return -1;
+}
+
+static const char *access_hook;
 
-static int git_daemon_config(const char *var, const char *value, void *cb)
+static int run_access_hook(struct daemon_service *service, const char *dir,
+                          const char *path, struct hostinfo *hi)
 {
-       if (!prefixcmp(var, "daemon.") &&
-           !strcmp(var + 7, service_looking_at->config_name)) {
-               service_enabled = git_config_bool(var, value);
-               return 0;
+       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;
+
+       *arg++ = access_hook;
+       *arg++ = service->name;
+       *arg++ = path;
+       *arg++ = hi->hostname.buf;
+       *arg++ = get_canon_hostname(hi);
+       *arg++ = get_ip_address(hi);
+       *arg++ = hi->tcp_port.buf;
+       *arg = NULL;
+
+       child.use_shell = 1;
+       child.argv = argv;
+       child.no_stdin = 1;
+       child.no_stderr = 1;
+       child.out = -1;
+       if (start_command(&child)) {
+               logerror("daemon access hook '%s' failed to start",
+                        access_hook);
+               goto error_return;
+       }
+       if (strbuf_read(&buf, child.out, 0) < 0) {
+               logerror("failed to read from pipe to daemon access hook '%s'",
+                        access_hook);
+               strbuf_reset(&buf);
+               seen_errors = 1;
+       }
+       if (close(child.out) < 0) {
+               logerror("failed to close pipe to daemon access hook '%s'",
+                        access_hook);
+               seen_errors = 1;
        }
+       if (finish_command(&child))
+               seen_errors = 1;
 
-       /* we are not interested in parsing any other configuration here */
-       return 0;
-}
+       if (!seen_errors) {
+               strbuf_release(&buf);
+               return 0;
+       }
 
-static int daemon_error(const char *dir, const char *msg)
-{
-       if (!informative_errors)
-               msg = "access denied or repository not exported";
-       packet_write(1, "ERR %s: %s", msg, dir);
+error_return:
+       strbuf_ltrim(&buf);
+       if (!buf.len)
+               strbuf_addstr(&buf, "service rejected");
+       eol = strchr(buf.buf, '\n');
+       if (eol)
+               *eol = '\0';
+       errno = EACCES;
+       daemon_error(dir, buf.buf);
+       strbuf_release(&buf);
        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 struct argv_array *env)
 {
        const char *path;
        int enabled = service->enabled;
+       struct strbuf var = STRBUF_INIT;
 
        loginfo("Request %s for '%s'", service->name, dir);
 
@@ -269,7 +391,7 @@ 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");
 
        /*
@@ -290,11 +412,9 @@ 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'",
@@ -304,12 +424,19 @@ 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, hi))
+               return -1;
+
+       /*
         * We'll ignore SIGTERM from now on, we have a
         * good client.
         */
        signal(SIGTERM, SIG_IGN);
 
-       return service->fn();
+       return service->fn(env);
 }
 
 static void copy_to_log(int fd)
@@ -324,7 +451,7 @@ static void copy_to_log(int fd)
                return;
        }
 
-       while (strbuf_getline(&line, fp, '\n') != EOF) {
+       while (strbuf_getline_lf(&line, fp) != EOF) {
                logerror("%s", line.buf);
                strbuf_setlen(&line, 0);
        }
@@ -333,47 +460,51 @@ static void copy_to_log(int fd)
        fclose(fp);
 }
 
-static int run_service_command(const char **argv)
+static int run_service_command(struct child_process *cld)
 {
-       struct child_process cld;
-
-       memset(&cld, 0, sizeof(cld));
-       cld.argv = argv;
-       cld.git_cmd = 1;
-       cld.err = -1;
-       if (start_command(&cld))
+       argv_array_push(&cld->args, ".");
+       cld->git_cmd = 1;
+       cld->err = -1;
+       if (start_command(cld))
                return -1;
 
        close(0);
        close(1);
 
-       copy_to_log(cld.err);
+       copy_to_log(cld->err);
 
-       return finish_command(&cld);
+       return finish_command(cld);
 }
 
-static int upload_pack(void)
+static int upload_pack(const struct argv_array *env)
 {
-       /* Timeout as string */
-       char timeout_buf[64];
-       const char *argv[] = { "upload-pack", "--strict", NULL, ".", NULL };
+       struct child_process cld = CHILD_PROCESS_INIT;
+       argv_array_pushl(&cld.args, "upload-pack", "--strict", NULL);
+       argv_array_pushf(&cld.args, "--timeout=%u", timeout);
 
-       argv[2] = timeout_buf;
+       argv_array_pushv(&cld.env_array, env->argv);
 
-       snprintf(timeout_buf, sizeof timeout_buf, "--timeout=%u", timeout);
-       return run_service_command(argv);
+       return run_service_command(&cld);
 }
 
-static int upload_archive(void)
+static int upload_archive(const struct argv_array *env)
 {
-       static const char *argv[] = { "upload-archive", ".", NULL };
-       return run_service_command(argv);
+       struct child_process cld = CHILD_PROCESS_INIT;
+       argv_array_push(&cld.args, "upload-archive");
+
+       argv_array_pushv(&cld.env_array, env->argv);
+
+       return run_service_command(&cld);
 }
 
-static int receive_pack(void)
+static int receive_pack(const struct argv_array *env)
 {
-       static const char *argv[] = { "receive-pack", ".", NULL };
-       return run_service_command(argv);
+       struct child_process cld = CHILD_PROCESS_INIT;
+       argv_array_push(&cld.args, "receive-pack");
+
+       argv_array_pushv(&cld.env_array, env->argv);
+
+       return run_service_command(&cld);
 }
 
 static struct daemon_service daemon_service[] = {
@@ -406,14 +537,6 @@ 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)
 {
@@ -442,30 +565,62 @@ 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.
+ *
+ * Returns a pointer to the character after the NUL byte terminating the host
+ * argument, or 'extra_args' if there is no host argument.
  */
-static void parse_host_arg(char *extra_args, int buflen)
+static char *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;
+                       loginfo("Extended attribute \"host\": %s", val);
                        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);
+                               if (port)
+                                       sanitize_client(&hi->tcp_port, port);
+                               canonicalize_client(&hi->hostname, host);
+                               hi->hostname_lookup_done = 0;
                        }
 
                        /* On to the next one */
@@ -475,10 +630,52 @@ static void parse_host_arg(char *extra_args, int buflen)
                        die("Invalid request");
        }
 
-       /*
-        * Locate canonical hostname and its IP address.
-        */
-       if (hostname) {
+       return extra_args;
+}
+
+static void parse_extra_args(struct hostinfo *hi, struct argv_array *env,
+                            char *extra_args, int buflen)
+{
+       const char *end = extra_args + buflen;
+       struct strbuf git_protocol = STRBUF_INIT;
+
+       /* First look for the host argument */
+       extra_args = parse_host_arg(hi, extra_args, buflen);
+
+       /* Look for additional arguments places after a second NUL byte */
+       for (; extra_args < end; extra_args += strlen(extra_args) + 1) {
+               const char *arg = extra_args;
+
+               /*
+                * Parse the extra arguments, adding most to 'git_protocol'
+                * which will be used to set the 'GIT_PROTOCOL' envvar in the
+                * service that will be run.
+                *
+                * If there ends up being a particular arg in the future that
+                * git-daemon needs to parse specifically (like the 'host' arg)
+                * then it can be parsed here and not added to 'git_protocol'.
+                */
+               if (*arg) {
+                       if (git_protocol.len > 0)
+                               strbuf_addch(&git_protocol, ':');
+                       strbuf_addstr(&git_protocol, arg);
+               }
+       }
+
+       if (git_protocol.len > 0) {
+               loginfo("Extended attribute \"protocol\": %s", git_protocol.buf);
+               argv_array_pushf(env, GIT_PROTOCOL_ENVIRONMENT "=%s",
+                                git_protocol.buf);
+       }
+       strbuf_release(&git_protocol);
+}
+
+/*
+ * 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;
@@ -488,18 +685,20 @@ 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);
                }
@@ -509,72 +708,99 @@ 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 void set_keep_alive(int sockfd)
+{
+       int ka = 1;
+
+       if (setsockopt(sockfd, SOL_SOCKET, SO_KEEPALIVE, &ka, sizeof(ka)) < 0) {
+               if (errno != ENOTSOCK)
+                       logerror("unable to set SO_KEEPALIVE on socket: %s",
+                               strerror(errno));
+       }
+}
 
 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;
+       struct argv_array env = ARGV_ARRAY_INIT;
+
+       hostinfo_init(&hi);
 
        if (addr)
                loginfo("Connection from %s:%s", addr, port);
 
+       set_keep_alive(0);
        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);
-       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 && line[len-1] == '\n')
+               line[len-1] = 0;
 
+       /* parse additional args hidden behind a NUL byte */
        if (len != pktlen)
-               parse_host_arg(line + len + 1, pktlen - len - 1);
+               parse_extra_args(&hi, &env, 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, &env);
+                       hostinfo_clear(&hi);
+                       argv_array_clear(&env);
+                       return rc;
                }
        }
 
+       hostinfo_clear(&hi);
+       argv_array_clear(&env);
        logerror("Protocol error: '%s'", line);
        return -1;
 }
@@ -661,17 +887,16 @@ static void check_dead_children(void)
                        /* remove the child */
                        *cradle = blanket->next;
                        live_children--;
+                       child_process_clear(&blanket->cld);
                        free(blanket);
                } else
                        cradle = &blanket->next;
 }
 
-static char **cld_argv;
+static struct argv_array cld_argv = ARGV_ARRAY_INIT;
 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 };
+       struct child_process cld = CHILD_PROCESS_INIT;
 
        if (max_connections && live_children >= max_connections) {
                kill_some_child();
@@ -685,28 +910,24 @@ static void handle(int incoming, struct sockaddr *addr, socklen_t addrlen)
        }
 
        if (addr->sa_family == AF_INET) {
+               char buf[128] = "";
                struct sockaddr_in *sin_addr = (void *) addr;
-               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));
+               inet_ntop(addr->sa_family, &sin_addr->sin_addr, buf, sizeof(buf));
+               argv_array_pushf(&cld.env_array, "REMOTE_ADDR=%s", buf);
+               argv_array_pushf(&cld.env_array, "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) {
+               char buf[128] = "";
                struct sockaddr_in6 *sin6_addr = (void *) addr;
-
-               char *buf = addrbuf + 12;
-               *buf++ = '['; *buf = '\0'; /* stpcpy() is cool */
-               inet_ntop(AF_INET6, &sin6_addr->sin6_addr, buf,
-                   sizeof(addrbuf) - 13);
-               strcat(buf, "]");
-
-               snprintf(portbuf, sizeof(portbuf), "REMOTE_PORT=%d",
-                   ntohs(sin6_addr->sin6_port));
+               inet_ntop(AF_INET6, &sin6_addr->sin6_addr, buf, sizeof(buf));
+               argv_array_pushf(&cld.env_array, "REMOTE_ADDR=[%s]", buf);
+               argv_array_pushf(&cld.env_array, "REMOTE_PORT=%d",
+                                ntohs(sin6_addr->sin6_port));
 #endif
        }
 
-       cld.env = (const char **)env;
-       cld.argv = (const char **)cld_argv;
+       cld.argv = cld_argv.argv;
        cld.in = incoming;
        cld.out = dup(incoming);
 
@@ -714,7 +935,6 @@ 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)
@@ -761,7 +981,7 @@ static const char *ip2str(int family, struct sockaddr *sin, socklen_t len)
                inet_ntop(family, &((struct sockaddr_in*)sin)->sin_addr, ip, len);
                break;
        default:
-               strcpy(ip, "<unknown>");
+               xsnprintf(ip, sizeof(ip), "<unknown>");
        }
        return ip;
 }
@@ -771,13 +991,12 @@ 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;
        long flags;
 
-       sprintf(pbuf, "%d", listen_port);
+       xsnprintf(pbuf, sizeof(pbuf), "%d", listen_port);
        memset(&hints, 0, sizeof(hints));
        hints.ai_family = AF_UNSPEC;
        hints.ai_socktype = SOCK_STREAM;
@@ -817,6 +1036,8 @@ static int setup_named_sock(char *listen_addr, int listen_port, struct socketlis
                        continue;
                }
 
+               set_keep_alive(sockfd);
+
                if (bind(sockfd, ai->ai_addr, ai->ai_addrlen) < 0) {
                        logerror("Could not bind to %s: %s",
                                 ip2str(ai->ai_family, ai->ai_addr, ai->ai_addrlen),
@@ -839,9 +1060,6 @@ 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);
@@ -879,8 +1097,10 @@ static int setup_named_sock(char *listen_addr, int listen_port, struct socketlis
                return 0;
        }
 
+       set_keep_alive(sockfd);
+
        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);
@@ -978,18 +1198,6 @@ 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;
@@ -999,11 +1207,6 @@ 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)
 {
@@ -1045,35 +1248,8 @@ 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)
 {
@@ -1091,7 +1267,7 @@ static int serve(struct string_list *listen_addr, int listen_port,
        return service_loop(&socklist);
 }
 
-int main(int argc, char **argv)
+int cmd_main(int argc, const char **argv)
 {
        int listen_port = 0;
        struct string_list listen_addr = STRING_LIST_INIT_NODUP;
@@ -1101,22 +1277,19 @@ int main(int argc, char **argv)
        struct credentials *cred = NULL;
        int i;
 
-       git_setup_gettext();
-
-       git_extract_argv0_path(argv[0]);
-
        for (i = 1; i < argc; i++) {
-               char *arg = argv[i];
+               const 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;
                        }
@@ -1127,7 +1300,6 @@ int main(int argc, char **argv)
                }
                if (!strcmp(arg, "--inetd")) {
                        inetd_mode = 1;
-                       log_syslog = 1;
                        continue;
                }
                if (!strcmp(arg, "--verbose")) {
@@ -1135,23 +1307,40 @@ int main(int argc, char **argv)
                        continue;
                }
                if (!strcmp(arg, "--syslog")) {
-                       log_syslog = 1;
+                       log_destination = LOG_DESTINATION_SYSLOG;
                        continue;
                }
+               if (skip_prefix(arg, "--log-destination=", &v)) {
+                       if (!strcmp(v, "syslog")) {
+                               log_destination = LOG_DESTINATION_SYSLOG;
+                               continue;
+                       } else if (!strcmp(v, "stderr")) {
+                               log_destination = LOG_DESTINATION_STDERR;
+                               continue;
+                       } else if (!strcmp(v, "none")) {
+                               log_destination = LOG_DESTINATION_NONE;
+                               continue;
+                       } else
+                               die("unknown log destination '%s'", v);
+               }
                if (!strcmp(arg, "--export-all")) {
                        export_all_trees = 1;
                        continue;
                }
-               if (!prefixcmp(arg, "--timeout=")) {
-                       timeout = atoi(arg+10);
+               if (skip_prefix(arg, "--access-hook=", &v)) {
+                       access_hook = v;
                        continue;
                }
-               if (!prefixcmp(arg, "--init-timeout=")) {
-                       init_timeout = atoi(arg+15);
+               if (skip_prefix(arg, "--timeout=", &v)) {
+                       timeout = atoi(v);
                        continue;
                }
-               if (!prefixcmp(arg, "--max-connections=")) {
-                       max_connections = atoi(arg+18);
+               if (skip_prefix(arg, "--init-timeout=", &v)) {
+                       init_timeout = atoi(v);
+                       continue;
+               }
+               if (skip_prefix(arg, "--max-connections=", &v)) {
+                       max_connections = atoi(v);
                        if (max_connections < 0)
                                max_connections = 0;            /* unlimited */
                        continue;
@@ -1160,16 +1349,16 @@ 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")) {
@@ -1180,48 +1369,47 @@ 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")) {
                        detach = 1;
-                       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;
                }
@@ -1236,7 +1424,14 @@ int main(int argc, char **argv)
                usage(daemon_usage);
        }
 
-       if (log_syslog) {
+       if (log_destination == LOG_DESTINATION_UNSET) {
+               if (inetd_mode || detach)
+                       log_destination = LOG_DESTINATION_SYSLOG;
+               else
+                       log_destination = LOG_DESTINATION_STDERR;
+       }
+
+       if (log_destination == LOG_DESTINATION_SYSLOG) {
                openlog("git-daemon", LOG_PID, LOG_DAEMON);
                set_die_routine(daemon_die);
        } else
@@ -1264,7 +1459,7 @@ int main(int argc, char **argv)
                die("base-path '%s' does not exist or is not a directory",
                    base_path);
 
-       if (inetd_mode) {
+       if (log_destination != LOG_DESTINATION_STDERR) {
                if (!freopen("/dev/null", "w", stderr))
                        die_errno("failed to redirect stderr to /dev/null");
        }
@@ -1272,21 +1467,19 @@ int main(int argc, char **argv)
        if (inetd_mode || serve_mode)
                return execute();
 
-       if (detach)
-               daemonize();
-       else
-               sanitize_stdfds();
+       if (detach) {
+               if (daemonize())
+                       die("--detach not supported on this platform");
+       }
 
        if (pid_file)
-               store_pid(pid_file);
+               write_file(pid_file, "%"PRIuMAX, (uintmax_t) getpid());
 
        /* prepare argv for serving-processes */
-       cld_argv = xmalloc(sizeof (char *) * (argc + 2));
-       cld_argv[0] = argv[0];  /* git-daemon */
-       cld_argv[1] = "--serve";
+       argv_array_push(&cld_argv, argv[0]); /* git-daemon */
+       argv_array_push(&cld_argv, "--serve");
        for (i = 1; i < argc; ++i)
-               cld_argv[i+1] = argv[i];
-       cld_argv[argc+1] = NULL;
+               argv_array_push(&cld_argv, argv[i]);
 
        return serve(&listen_addr, listen_port, cred);
 }