[thirdparty/systemd.git] / src / socket.c

/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/

/***
  This file is part of systemd.

  Copyright 2010 Lennart Poettering

  systemd is free software; you can redistribute it and/or modify it
  under the terms of the GNU General Public License as published by
  the Free Software Foundation; either version 2 of the License, or
  (at your option) any later version.

  systemd is distributed in the hope that it will be useful, but
  WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/

#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <errno.h>
#include <fcntl.h>
#include <sys/epoll.h>
#include <signal.h>
#include <arpa/inet.h>
#include <mqueue.h>

#include "unit.h"
#include "socket.h"
#include "netinet/tcp.h"
#include "log.h"
#include "load-dropin.h"
#include "load-fragment.h"
#include "strv.h"
#include "unit-name.h"
#include "dbus-socket.h"
#include "missing.h"
#include "special.h"
#include "bus-errors.h"
#include "label.h"
#include "exit-status.h"
#include "def.h"

static const UnitActiveState state_translation_table[_SOCKET_STATE_MAX] = {
        [SOCKET_DEAD] = UNIT_INACTIVE,
        [SOCKET_START_PRE] = UNIT_ACTIVATING,
        [SOCKET_START_POST] = UNIT_ACTIVATING,
        [SOCKET_LISTENING] = UNIT_ACTIVE,
        [SOCKET_RUNNING] = UNIT_ACTIVE,
        [SOCKET_STOP_PRE] = UNIT_DEACTIVATING,
        [SOCKET_STOP_PRE_SIGTERM] = UNIT_DEACTIVATING,
        [SOCKET_STOP_PRE_SIGKILL] = UNIT_DEACTIVATING,
        [SOCKET_STOP_POST] = UNIT_DEACTIVATING,
        [SOCKET_FINAL_SIGTERM] = UNIT_DEACTIVATING,
        [SOCKET_FINAL_SIGKILL] = UNIT_DEACTIVATING,
        [SOCKET_FAILED] = UNIT_FAILED
};

static void socket_init(Unit *u) {
        Socket *s = SOCKET(u);

        assert(u);
        assert(u->load_state == UNIT_STUB);

        s->backlog = SOMAXCONN;
        s->timeout_usec = DEFAULT_TIMEOUT_USEC;
        s->directory_mode = 0755;
        s->socket_mode = 0666;

        s->max_connections = 64;

        s->priority = -1;
        s->ip_tos = -1;
        s->ip_ttl = -1;
        s->mark = -1;

        exec_context_init(&s->exec_context);
        s->exec_context.std_output = u->manager->default_std_output;
        s->exec_context.std_error = u->manager->default_std_error;

        s->control_command_id = _SOCKET_EXEC_COMMAND_INVALID;
}

static void socket_unwatch_control_pid(Socket *s) {
        assert(s);

        if (s->control_pid <= 0)
                return;

        unit_unwatch_pid(UNIT(s), s->control_pid);
        s->control_pid = 0;
}

static void socket_done(Unit *u) {
        Socket *s = SOCKET(u);
        SocketPort *p;

        assert(s);

        while ((p = s->ports)) {
                LIST_REMOVE(SocketPort, port, s->ports, p);

                if (p->fd >= 0) {
                        unit_unwatch_fd(UNIT(s), &p->fd_watch);
                        close_nointr_nofail(p->fd);
                }

                free(p->path);
                free(p);
        }

        exec_context_done(&s->exec_context);
        exec_command_free_array(s->exec_command, _SOCKET_EXEC_COMMAND_MAX);
        s->control_command = NULL;

        socket_unwatch_control_pid(s);

        unit_ref_unset(&s->service);

        free(s->tcp_congestion);
        s->tcp_congestion = NULL;

        free(s->bind_to_device);
        s->bind_to_device = NULL;

        unit_unwatch_timer(u, &s->timer_watch);
}

static int socket_instantiate_service(Socket *s) {
        char *prefix, *name;
        int r;
        Unit *u;

        assert(s);

        /* This fills in s->service if it isn't filled in yet. For
         * Accept=yes sockets we create the next connection service
         * here. For Accept=no this is mostly a NOP since the service
         * is figured out at load time anyway. */

        if (UNIT_DEREF(s->service))
                return 0;

        assert(s->accept);

        if (!(prefix = unit_name_to_prefix(UNIT(s)->id)))
                return -ENOMEM;

        r = asprintf(&name, "%s@%u.service", prefix, s->n_accepted);
        free(prefix);

        if (r < 0)
                return -ENOMEM;

        r = manager_load_unit(UNIT(s)->manager, name, NULL, NULL, &u);
        free(name);

        if (r < 0)
                return r;

#ifdef HAVE_SYSV_COMPAT
        if (SERVICE(u)->sysv_path) {
                log_error("Using SysV services for socket activation is not supported. Refusing.");
                return -ENOENT;
        }
#endif

        u->no_gc = true;
        unit_ref_set(&s->service, u);

        return unit_add_two_dependencies(UNIT(s), UNIT_BEFORE, UNIT_TRIGGERS, u, false);
}

static bool have_non_accept_socket(Socket *s) {
        SocketPort *p;

        assert(s);

        if (!s->accept)
                return true;

        LIST_FOREACH(port, p, s->ports) {

                if (p->type != SOCKET_SOCKET)
                        return true;

                if (!socket_address_can_accept(&p->address))
                        return true;
        }

        return false;
}

static int socket_verify(Socket *s) {
        assert(s);

        if (UNIT(s)->load_state != UNIT_LOADED)
                return 0;

        if (!s->ports) {
                log_error("%s lacks Listen setting. Refusing.", UNIT(s)->id);
                return -EINVAL;
        }

        if (s->accept && have_non_accept_socket(s)) {
                log_error("%s configured for accepting sockets, but sockets are non-accepting. Refusing.", UNIT(s)->id);
                return -EINVAL;
        }

        if (s->accept && s->max_connections <= 0) {
                log_error("%s's MaxConnection setting too small. Refusing.", UNIT(s)->id);
                return -EINVAL;
        }

        if (s->accept && UNIT_DEREF(s->service)) {
                log_error("Explicit service configuration for accepting sockets not supported on %s. Refusing.", UNIT(s)->id);
                return -EINVAL;
        }

        if (s->exec_context.pam_name && s->exec_context.kill_mode != KILL_CONTROL_GROUP) {
                log_error("%s has PAM enabled. Kill mode must be set to 'control-group'. Refusing.", UNIT(s)->id);
                return -EINVAL;
        }

        return 0;
}

static bool socket_needs_mount(Socket *s, const char *prefix) {
        SocketPort *p;

        assert(s);

        LIST_FOREACH(port, p, s->ports) {

                if (p->type == SOCKET_SOCKET) {
                        if (socket_address_needs_mount(&p->address, prefix))
                                return true;
                } else if (p->type == SOCKET_FIFO || p->type == SOCKET_SPECIAL) {
                        if (path_startswith(p->path, prefix))
                                return true;
                }
        }

        return false;
}

int socket_add_one_mount_link(Socket *s, Mount *m) {
        int r;

        assert(s);
        assert(m);

        if (UNIT(s)->load_state != UNIT_LOADED ||
            UNIT(m)->load_state != UNIT_LOADED)
                return 0;

        if (!socket_needs_mount(s, m->where))
                return 0;

        if ((r = unit_add_two_dependencies(UNIT(s), UNIT_AFTER, UNIT_REQUIRES, UNIT(m), true)) < 0)
                return r;

        return 0;
}

static int socket_add_mount_links(Socket *s) {
        Unit *other;
        int r;

        assert(s);

        LIST_FOREACH(units_by_type, other, UNIT(s)->manager->units_by_type[UNIT_MOUNT])
                if ((r = socket_add_one_mount_link(s, MOUNT(other))) < 0)
                        return r;

        return 0;
}

static int socket_add_device_link(Socket *s) {
        char *t;
        int r;

        assert(s);

        if (!s->bind_to_device)
                return 0;

        if (asprintf(&t, "/sys/subsystem/net/devices/%s", s->bind_to_device) < 0)
                return -ENOMEM;

        r = unit_add_node_link(UNIT(s), t, false);
        free(t);

        return r;
}

static int socket_add_default_dependencies(Socket *s) {
        int r;
        assert(s);

        if (UNIT(s)->manager->running_as == MANAGER_SYSTEM) {
                if ((r = unit_add_dependency_by_name(UNIT(s), UNIT_BEFORE, SPECIAL_SOCKETS_TARGET, NULL, true)) < 0)
                        return r;

                if ((r = unit_add_two_dependencies_by_name(UNIT(s), UNIT_AFTER, UNIT_REQUIRES, SPECIAL_SYSINIT_TARGET, NULL, true)) < 0)
                        return r;
        }

        return unit_add_two_dependencies_by_name(UNIT(s), UNIT_BEFORE, UNIT_CONFLICTS, SPECIAL_SHUTDOWN_TARGET, NULL, true);
}

static bool socket_has_exec(Socket *s) {
        unsigned i;
        assert(s);

        for (i = 0; i < _SOCKET_EXEC_COMMAND_MAX; i++)
                if (s->exec_command[i])
                        return true;

        return false;
}

static int socket_load(Unit *u) {
        Socket *s = SOCKET(u);
        int r;

        assert(u);
        assert(u->load_state == UNIT_STUB);

        if ((r = unit_load_fragment_and_dropin(u)) < 0)
                return r;

        /* This is a new unit? Then let's add in some extras */
        if (u->load_state == UNIT_LOADED) {

                if (have_non_accept_socket(s)) {

                        if (!UNIT_DEREF(s->service)) {
                                Unit *x;

                                r = unit_load_related_unit(u, ".service", &x);
                                if (r < 0)
                                        return r;

                                unit_ref_set(&s->service, x);
                        }

                        r = unit_add_two_dependencies(u, UNIT_BEFORE, UNIT_TRIGGERS, UNIT_DEREF(s->service), true);
                        if (r < 0)
                                return r;
                }

                if ((r = socket_add_mount_links(s)) < 0)
                        return r;

                if ((r = socket_add_device_link(s)) < 0)
                        return r;

                if (socket_has_exec(s))
                        if ((r = unit_add_exec_dependencies(u, &s->exec_context)) < 0)
                                return r;

                if ((r = unit_add_default_cgroups(u)) < 0)
                        return r;

                if (UNIT(s)->default_dependencies)
                        if ((r = socket_add_default_dependencies(s)) < 0)
                                return r;
        }

        return socket_verify(s);
}

static const char* listen_lookup(int family, int type) {

        if (family == AF_NETLINK)
                return "ListenNetlink";

        if (type == SOCK_STREAM)
                return "ListenStream";
        else if (type == SOCK_DGRAM)
                return "ListenDatagram";
        else if (type == SOCK_SEQPACKET)
                return "ListenSequentialPacket";

        assert_not_reached("Unknown socket type");
        return NULL;
}

static void socket_dump(Unit *u, FILE *f, const char *prefix) {

        SocketExecCommand c;
        Socket *s = SOCKET(u);
        SocketPort *p;
        const char *prefix2;
        char *p2;

        assert(s);
        assert(f);

        p2 = strappend(prefix, "\t");
        prefix2 = p2 ? p2 : prefix;

        fprintf(f,
                "%sSocket State: %s\n"
                "%sResult: %s\n"
                "%sBindIPv6Only: %s\n"
                "%sBacklog: %u\n"
                "%sSocketMode: %04o\n"
                "%sDirectoryMode: %04o\n"
                "%sKeepAlive: %s\n"
                "%sFreeBind: %s\n"
                "%sTransparent: %s\n"
                "%sBroadcast: %s\n"
                "%sPassCredentials: %s\n"
                "%sPassSecurity: %s\n"
                "%sTCPCongestion: %s\n",
                prefix, socket_state_to_string(s->state),
                prefix, socket_result_to_string(s->result),
                prefix, socket_address_bind_ipv6_only_to_string(s->bind_ipv6_only),
                prefix, s->backlog,
                prefix, s->socket_mode,
                prefix, s->directory_mode,
                prefix, yes_no(s->keep_alive),
                prefix, yes_no(s->free_bind),
                prefix, yes_no(s->transparent),
                prefix, yes_no(s->broadcast),
                prefix, yes_no(s->pass_cred),
                prefix, yes_no(s->pass_sec),
                prefix, strna(s->tcp_congestion));

        if (s->control_pid > 0)
                fprintf(f,
                        "%sControl PID: %lu\n",
                        prefix, (unsigned long) s->control_pid);

        if (s->bind_to_device)
                fprintf(f,
                        "%sBindToDevice: %s\n",
                        prefix, s->bind_to_device);

        if (s->accept)
                fprintf(f,
                        "%sAccepted: %u\n"
                        "%sNConnections: %u\n"
                        "%sMaxConnections: %u\n",
                        prefix, s->n_accepted,
                        prefix, s->n_connections,
                        prefix, s->max_connections);

        if (s->priority >= 0)
                fprintf(f,
                        "%sPriority: %i\n",
                        prefix, s->priority);

        if (s->receive_buffer > 0)
                fprintf(f,
                        "%sReceiveBuffer: %zu\n",
                        prefix, s->receive_buffer);

        if (s->send_buffer > 0)
                fprintf(f,
                        "%sSendBuffer: %zu\n",
                        prefix, s->send_buffer);

        if (s->ip_tos >= 0)
                fprintf(f,
                        "%sIPTOS: %i\n",
                        prefix, s->ip_tos);

        if (s->ip_ttl >= 0)
                fprintf(f,
                        "%sIPTTL: %i\n",
                        prefix, s->ip_ttl);

        if (s->pipe_size > 0)
                fprintf(f,
                        "%sPipeSize: %zu\n",
                        prefix, s->pipe_size);

        if (s->mark >= 0)
                fprintf(f,
                        "%sMark: %i\n",
                        prefix, s->mark);

        if (s->mq_maxmsg > 0)
                fprintf(f,
                        "%sMessageQueueMaxMessages: %li\n",
                        prefix, s->mq_maxmsg);

        if (s->mq_msgsize > 0)
                fprintf(f,
                        "%sMessageQueueMessageSize: %li\n",
                        prefix, s->mq_msgsize);

        LIST_FOREACH(port, p, s->ports) {

                if (p->type == SOCKET_SOCKET) {
                        const char *t;
                        int r;
                        char *k = NULL;

                        if ((r = socket_address_print(&p->address, &k)) < 0)
                                t = strerror(-r);
                        else
                                t = k;

                        fprintf(f, "%s%s: %s\n", prefix, listen_lookup(socket_address_family(&p->address), p->address.type), t);
                        free(k);
                } else if (p->type == SOCKET_SPECIAL)
                        fprintf(f, "%sListenSpecial: %s\n", prefix, p->path);
                else if (p->type == SOCKET_MQUEUE)
                        fprintf(f, "%sListenMessageQueue: %s\n", prefix, p->path);
                else
                        fprintf(f, "%sListenFIFO: %s\n", prefix, p->path);
        }

        exec_context_dump(&s->exec_context, f, prefix);

        for (c = 0; c < _SOCKET_EXEC_COMMAND_MAX; c++) {
                if (!s->exec_command[c])
                        continue;

                fprintf(f, "%s-> %s:\n",
                        prefix, socket_exec_command_to_string(c));

                exec_command_dump_list(s->exec_command[c], f, prefix2);
        }

        free(p2);
}

static int instance_from_socket(int fd, unsigned nr, char **instance) {
        socklen_t l;
        char *r;
        union {
                struct sockaddr sa;
                struct sockaddr_un un;
                struct sockaddr_in in;
                struct sockaddr_in6 in6;
                struct sockaddr_storage storage;
        } local, remote;

        assert(fd >= 0);
        assert(instance);

        l = sizeof(local);
        if (getsockname(fd, &local.sa, &l) < 0)
                return -errno;

        l = sizeof(remote);
        if (getpeername(fd, &remote.sa, &l) < 0)
                return -errno;

        switch (local.sa.sa_family) {

        case AF_INET: {
                uint32_t
                        a = ntohl(local.in.sin_addr.s_addr),
                        b = ntohl(remote.in.sin_addr.s_addr);

                if (asprintf(&r,
                             "%u.%u.%u.%u:%u-%u.%u.%u.%u:%u",
                             a >> 24, (a >> 16) & 0xFF, (a >> 8) & 0xFF, a & 0xFF,
                             ntohs(local.in.sin_port),
                             b >> 24, (b >> 16) & 0xFF, (b >> 8) & 0xFF, b & 0xFF,
                             ntohs(remote.in.sin_port)) < 0)
                        return -ENOMEM;

                break;
        }

        case AF_INET6: {
                static const char ipv4_prefix[] = {
                        0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0xFF, 0xFF
                };

                if (memcmp(&local.in6.sin6_addr, ipv4_prefix, sizeof(ipv4_prefix)) == 0 &&
                    memcmp(&remote.in6.sin6_addr, ipv4_prefix, sizeof(ipv4_prefix)) == 0) {
                        const uint8_t
                                *a = local.in6.sin6_addr.s6_addr+12,
                                *b = remote.in6.sin6_addr.s6_addr+12;

                        if (asprintf(&r,
                                     "%u.%u.%u.%u:%u-%u.%u.%u.%u:%u",
                                     a[0], a[1], a[2], a[3],
                                     ntohs(local.in6.sin6_port),
                                     b[0], b[1], b[2], b[3],
                                     ntohs(remote.in6.sin6_port)) < 0)
                                return -ENOMEM;
                } else {
                        char a[INET6_ADDRSTRLEN], b[INET6_ADDRSTRLEN];

                        if (asprintf(&r,
                                     "%s:%u-%s:%u",
                                     inet_ntop(AF_INET6, &local.in6.sin6_addr, a, sizeof(a)),
                                     ntohs(local.in6.sin6_port),
                                     inet_ntop(AF_INET6, &remote.in6.sin6_addr, b, sizeof(b)),
                                     ntohs(remote.in6.sin6_port)) < 0)
                                return -ENOMEM;
                }

                break;
        }

        case AF_UNIX: {
                struct ucred ucred;

                l = sizeof(ucred);
                if (getsockopt(fd, SOL_SOCKET, SO_PEERCRED, &ucred, &l) < 0)
                        return -errno;

                if (asprintf(&r,
                             "%u-%lu-%lu",
                             nr,
                             (unsigned long) ucred.pid,
                             (unsigned long) ucred.uid) < 0)
                        return -ENOMEM;

                break;
        }

        default:
                assert_not_reached("Unhandled socket type.");
        }

        *instance = r;
        return 0;
}

static void socket_close_fds(Socket *s) {
        SocketPort *p;

        assert(s);

        LIST_FOREACH(port, p, s->ports) {
                if (p->fd < 0)
                        continue;

                unit_unwatch_fd(UNIT(s), &p->fd_watch);
                close_nointr_nofail(p->fd);

                /* One little note: we should never delete any sockets
                 * in the file system here! After all some other
                 * process we spawned might still have a reference of
                 * this fd and wants to continue to use it. Therefore
                 * we delete sockets in the file system before we
                 * create a new one, not after we stopped using
                 * one! */

                p->fd = -1;
        }
}

static void socket_apply_socket_options(Socket *s, int fd) {
        assert(s);
        assert(fd >= 0);

        if (s->keep_alive) {
                int b = s->keep_alive;
                if (setsockopt(fd, SOL_SOCKET, SO_KEEPALIVE, &b, sizeof(b)) < 0)
                        log_warning("SO_KEEPALIVE failed: %m");
        }

        if (s->broadcast) {
                int one = 1;
                if (setsockopt(fd, SOL_SOCKET, SO_BROADCAST, &one, sizeof(one)) < 0)
                        log_warning("SO_BROADCAST failed: %m");
        }

        if (s->pass_cred) {
                int one = 1;
                if (setsockopt(fd, SOL_SOCKET, SO_PASSCRED, &one, sizeof(one)) < 0)
                        log_warning("SO_PASSCRED failed: %m");
        }

        if (s->pass_sec) {
                int one = 1;
                if (setsockopt(fd, SOL_SOCKET, SO_PASSSEC, &one, sizeof(one)) < 0)
                        log_warning("SO_PASSSEC failed: %m");
        }

        if (s->priority >= 0)
                if (setsockopt(fd, SOL_SOCKET, SO_PRIORITY, &s->priority, sizeof(s->priority)) < 0)
                        log_warning("SO_PRIORITY failed: %m");

        if (s->receive_buffer > 0) {
                int value = (int) s->receive_buffer;

                /* We first try with SO_RCVBUFFORCE, in case we have the perms for that */

                if (setsockopt(fd, SOL_SOCKET, SO_RCVBUFFORCE, &value, sizeof(value)) < 0)
                        if (setsockopt(fd, SOL_SOCKET, SO_RCVBUF, &value, sizeof(value)) < 0)
                                log_warning("SO_RCVBUF failed: %m");
        }

        if (s->send_buffer > 0) {
                int value = (int) s->send_buffer;
                if (setsockopt(fd, SOL_SOCKET, SO_SNDBUFFORCE, &value, sizeof(value)) < 0)
                        if (setsockopt(fd, SOL_SOCKET, SO_SNDBUF, &value, sizeof(value)) < 0)
                                log_warning("SO_SNDBUF failed: %m");
        }

        if (s->mark >= 0)
                if (setsockopt(fd, SOL_SOCKET, SO_MARK, &s->mark, sizeof(s->mark)) < 0)
                        log_warning("SO_MARK failed: %m");

        if (s->ip_tos >= 0)
                if (setsockopt(fd, IPPROTO_IP, IP_TOS, &s->ip_tos, sizeof(s->ip_tos)) < 0)
                        log_warning("IP_TOS failed: %m");

        if (s->ip_ttl >= 0) {
                int r, x;

                r = setsockopt(fd, IPPROTO_IP, IP_TTL, &s->ip_ttl, sizeof(s->ip_ttl));

                if (socket_ipv6_is_supported())
                        x = setsockopt(fd, IPPROTO_IPV6, IPV6_UNICAST_HOPS, &s->ip_ttl, sizeof(s->ip_ttl));
                else {
                        x = -1;
                        errno = EAFNOSUPPORT;
                }

                if (r < 0 && x < 0)
                        log_warning("IP_TTL/IPV6_UNICAST_HOPS failed: %m");
        }

        if (s->tcp_congestion)
                if (setsockopt(fd, SOL_TCP, TCP_CONGESTION, s->tcp_congestion, strlen(s->tcp_congestion)+1) < 0)
                        log_warning("TCP_CONGESTION failed: %m");
}

static void socket_apply_fifo_options(Socket *s, int fd) {
        assert(s);
        assert(fd >= 0);

        if (s->pipe_size > 0)
                if (fcntl(fd, F_SETPIPE_SZ, s->pipe_size) < 0)
                        log_warning("F_SETPIPE_SZ: %m");
}

static int fifo_address_create(
                const char *path,
                mode_t directory_mode,
                mode_t socket_mode,
                int *_fd) {

        int fd = -1, r = 0;
        struct stat st;
        mode_t old_mask;

        assert(path);
        assert(_fd);

        mkdir_parents(path, directory_mode);

        if ((r = label_fifofile_set(path)) < 0)
                goto fail;

        /* Enforce the right access mode for the fifo */
        old_mask = umask(~ socket_mode);

        /* Include the original umask in our mask */
        umask(~socket_mode | old_mask);

        r = mkfifo(path, socket_mode);
        umask(old_mask);

        if (r < 0 && errno != EEXIST) {
                r = -errno;
                goto fail;
        }

        if ((fd = open(path, O_RDWR|O_CLOEXEC|O_NOCTTY|O_NONBLOCK|O_NOFOLLOW)) < 0) {
                r = -errno;
                goto fail;
        }

        label_file_clear();

        if (fstat(fd, &st) < 0) {
                r = -errno;
                goto fail;
        }

        if (!S_ISFIFO(st.st_mode) ||
            (st.st_mode & 0777) != (socket_mode & ~old_mask) ||
            st.st_uid != getuid() ||
            st.st_gid != getgid()) {

                r = -EEXIST;
                goto fail;
        }

        *_fd = fd;
        return 0;

fail:
        label_file_clear();

        if (fd >= 0)
                close_nointr_nofail(fd);

        return r;
}

static int special_address_create(
                const char *path,
                int *_fd) {

        int fd = -1, r = 0;
        struct stat st;

        assert(path);
        assert(_fd);

        if ((fd = open(path, O_RDONLY|O_CLOEXEC|O_NOCTTY|O_NONBLOCK|O_NOFOLLOW)) < 0) {
                r = -errno;
                goto fail;
        }

        if (fstat(fd, &st) < 0) {
                r = -errno;
                goto fail;
        }

        /* Check whether this is a /proc, /sys or /dev file or char device */
        if (!S_ISREG(st.st_mode) && !S_ISCHR(st.st_mode)) {
                r = -EEXIST;
                goto fail;
        }

        *_fd = fd;
        return 0;

fail:
        if (fd >= 0)
                close_nointr_nofail(fd);

        return r;
}

static int mq_address_create(
                const char *path,
                mode_t mq_mode,
                long maxmsg,
                long msgsize,
                int *_fd) {

        int fd = -1, r = 0;
        struct stat st;
        mode_t old_mask;
        struct mq_attr _attr, *attr = NULL;

        assert(path);
        assert(_fd);

        if (maxmsg > 0 && msgsize > 0) {
                zero(_attr);
                _attr.mq_flags = O_NONBLOCK;
                _attr.mq_maxmsg = maxmsg;
                _attr.mq_msgsize = msgsize;
                attr = &_attr;
        }

        /* Enforce the right access mode for the mq */
        old_mask = umask(~ mq_mode);

        /* Include the original umask in our mask */
        umask(~mq_mode | old_mask);

        fd = mq_open(path, O_RDONLY|O_CLOEXEC|O_NONBLOCK|O_CREAT, mq_mode, attr);
        umask(old_mask);

        if (fd < 0) {
                r = -errno;
                goto fail;
        }

        if (fstat(fd, &st) < 0) {
                r = -errno;
                goto fail;
        }

        if ((st.st_mode & 0777) != (mq_mode & ~old_mask) ||
            st.st_uid != getuid() ||
            st.st_gid != getgid()) {

                r = -EEXIST;
                goto fail;
        }

        *_fd = fd;
        return 0;

fail:
        if (fd >= 0)
                close_nointr_nofail(fd);

        return r;
}

static int socket_open_fds(Socket *s) {
        SocketPort *p;
        int r;
        char *label = NULL;
        bool know_label = false;

        assert(s);

        LIST_FOREACH(port, p, s->ports) {

                if (p->fd >= 0)
                        continue;

                if (p->type == SOCKET_SOCKET) {

                        if (!know_label) {

                                if ((r = socket_instantiate_service(s)) < 0)
                                        return r;

                                if (UNIT_DEREF(s->service) &&
                                    SERVICE(UNIT_DEREF(s->service))->exec_command[SERVICE_EXEC_START]) {
                                        r = label_get_create_label_from_exe(SERVICE(UNIT_DEREF(s->service))->exec_command[SERVICE_EXEC_START]->path, &label);

                                        if (r < 0) {
                                                if (r != -EPERM)
                                                        return r;
                                        }
                                }

                                know_label = true;
                        }

                        if ((r = socket_address_listen(
                                             &p->address,
                                             s->backlog,
                                             s->bind_ipv6_only,
                                             s->bind_to_device,
                                             s->free_bind,
                                             s->transparent,
                                             s->directory_mode,
                                             s->socket_mode,
                                             label,
                                             &p->fd)) < 0)
                                goto rollback;

                        socket_apply_socket_options(s, p->fd);

                } else  if (p->type == SOCKET_SPECIAL) {

                        if ((r = special_address_create(
                                             p->path,
                                             &p->fd)) < 0)
                                goto rollback;

                } else  if (p->type == SOCKET_FIFO) {

                        if ((r = fifo_address_create(
                                             p->path,
                                             s->directory_mode,
                                             s->socket_mode,
                                             &p->fd)) < 0)
                                goto rollback;

                        socket_apply_fifo_options(s, p->fd);
                } else if (p->type == SOCKET_MQUEUE) {

                        if ((r = mq_address_create(
                                             p->path,
                                             s->socket_mode,
                                             s->mq_maxmsg,
                                             s->mq_msgsize,
                                             &p->fd)) < 0)
                                goto rollback;
                } else
                        assert_not_reached("Unknown port type");
        }

        label_free(label);
        return 0;

rollback:
        socket_close_fds(s);
        label_free(label);
        return r;
}

static void socket_unwatch_fds(Socket *s) {
        SocketPort *p;

        assert(s);

        LIST_FOREACH(port, p, s->ports) {
                if (p->fd < 0)
                        continue;

                unit_unwatch_fd(UNIT(s), &p->fd_watch);
        }
}

static int socket_watch_fds(Socket *s) {
        SocketPort *p;
        int r;

        assert(s);

        LIST_FOREACH(port, p, s->ports) {
                if (p->fd < 0)
                        continue;

                p->fd_watch.socket_accept =
                        s->accept &&
                        p->type == SOCKET_SOCKET &&
                        socket_address_can_accept(&p->address);

                if ((r = unit_watch_fd(UNIT(s), p->fd, EPOLLIN, &p->fd_watch)) < 0)
                        goto fail;
        }

        return 0;

fail:
        socket_unwatch_fds(s);
        return r;
}

static void socket_set_state(Socket *s, SocketState state) {
        SocketState old_state;
        assert(s);

        old_state = s->state;
        s->state = state;

        if (state != SOCKET_START_PRE &&
            state != SOCKET_START_POST &&
            state != SOCKET_STOP_PRE &&
            state != SOCKET_STOP_PRE_SIGTERM &&
            state != SOCKET_STOP_PRE_SIGKILL &&
            state != SOCKET_STOP_POST &&
            state != SOCKET_FINAL_SIGTERM &&
            state != SOCKET_FINAL_SIGKILL) {
                unit_unwatch_timer(UNIT(s), &s->timer_watch);
                socket_unwatch_control_pid(s);
                s->control_command = NULL;
                s->control_command_id = _SOCKET_EXEC_COMMAND_INVALID;
        }

        if (state != SOCKET_LISTENING)
                socket_unwatch_fds(s);

        if (state != SOCKET_START_POST &&
            state != SOCKET_LISTENING &&
            state != SOCKET_RUNNING &&
            state != SOCKET_STOP_PRE &&
            state != SOCKET_STOP_PRE_SIGTERM &&
            state != SOCKET_STOP_PRE_SIGKILL)
                socket_close_fds(s);

        if (state != old_state)
                log_debug("%s changed %s -> %s",
                          UNIT(s)->id,
                          socket_state_to_string(old_state),
                          socket_state_to_string(state));

        unit_notify(UNIT(s), state_translation_table[old_state], state_translation_table[state], true);
}

static int socket_coldplug(Unit *u) {
        Socket *s = SOCKET(u);
        int r;

        assert(s);
        assert(s->state == SOCKET_DEAD);

        if (s->deserialized_state != s->state) {

                if (s->deserialized_state == SOCKET_START_PRE ||
                    s->deserialized_state == SOCKET_START_POST ||
                    s->deserialized_state == SOCKET_STOP_PRE ||
                    s->deserialized_state == SOCKET_STOP_PRE_SIGTERM ||
                    s->deserialized_state == SOCKET_STOP_PRE_SIGKILL ||
                    s->deserialized_state == SOCKET_STOP_POST ||
                    s->deserialized_state == SOCKET_FINAL_SIGTERM ||
                    s->deserialized_state == SOCKET_FINAL_SIGKILL) {

                        if (s->control_pid <= 0)
                                return -EBADMSG;

                        if ((r = unit_watch_pid(UNIT(s), s->control_pid)) < 0)
                                return r;

                        if ((r = unit_watch_timer(UNIT(s), s->timeout_usec, &s->timer_watch)) < 0)
                                return r;
                }

                if (s->deserialized_state == SOCKET_START_POST ||
                    s->deserialized_state == SOCKET_LISTENING ||
                    s->deserialized_state == SOCKET_RUNNING ||
                    s->deserialized_state == SOCKET_STOP_PRE ||
                    s->deserialized_state == SOCKET_STOP_PRE_SIGTERM ||
                    s->deserialized_state == SOCKET_STOP_PRE_SIGKILL)
                        if ((r = socket_open_fds(s)) < 0)
                                return r;

                if (s->deserialized_state == SOCKET_LISTENING)
                        if ((r = socket_watch_fds(s)) < 0)
                                return r;

                socket_set_state(s, s->deserialized_state);
        }

        return 0;
}

static int socket_spawn(Socket *s, ExecCommand *c, pid_t *_pid) {
        pid_t pid;
        int r;
        char **argv;

        assert(s);
        assert(c);
        assert(_pid);

        if ((r = unit_watch_timer(UNIT(s), s->timeout_usec, &s->timer_watch)) < 0)
                goto fail;

        if (!(argv = unit_full_printf_strv(UNIT(s), c->argv))) {
                r = -ENOMEM;
                goto fail;
        }

        r = exec_spawn(c,
                       argv,
                       &s->exec_context,
                       NULL, 0,
                       UNIT(s)->manager->environment,
                       true,
                       true,
                       true,
                       UNIT(s)->manager->confirm_spawn,
                       UNIT(s)->cgroup_bondings,
                       UNIT(s)->cgroup_attributes,
                       &pid);

        strv_free(argv);
        if (r < 0)
                goto fail;

        if ((r = unit_watch_pid(UNIT(s), pid)) < 0)
                /* FIXME: we need to do something here */
                goto fail;

        *_pid = pid;

        return 0;

fail:
        unit_unwatch_timer(UNIT(s), &s->timer_watch);

        return r;
}

static void socket_enter_dead(Socket *s, SocketResult f) {
        assert(s);

        if (f != SOCKET_SUCCESS)
                s->result = f;

        socket_set_state(s, s->result != SOCKET_SUCCESS ? SOCKET_FAILED : SOCKET_DEAD);
}

static void socket_enter_signal(Socket *s, SocketState state, SocketResult f);

static void socket_enter_stop_post(Socket *s, SocketResult f) {
        int r;
        assert(s);

        if (f != SOCKET_SUCCESS)
                s->result = f;

        socket_unwatch_control_pid(s);

        s->control_command_id = SOCKET_EXEC_STOP_POST;

        if ((s->control_command = s->exec_command[SOCKET_EXEC_STOP_POST])) {
                if ((r = socket_spawn(s, s->control_command, &s->control_pid)) < 0)
                        goto fail;

                socket_set_state(s, SOCKET_STOP_POST);
        } else
                socket_enter_signal(s, SOCKET_FINAL_SIGTERM, SOCKET_SUCCESS);

        return;

fail:
        log_warning("%s failed to run 'stop-post' task: %s", UNIT(s)->id, strerror(-r));
        socket_enter_signal(s, SOCKET_FINAL_SIGTERM, SOCKET_FAILURE_RESOURCES);
}

static void socket_enter_signal(Socket *s, SocketState state, SocketResult f) {
        int r;
        Set *pid_set = NULL;
        bool wait_for_exit = false;

        assert(s);

        if (f != SOCKET_SUCCESS)
                s->result = f;

        if (s->exec_context.kill_mode != KILL_NONE) {
                int sig = (state == SOCKET_STOP_PRE_SIGTERM || state == SOCKET_FINAL_SIGTERM) ? s->exec_context.kill_signal : SIGKILL;

                if (s->control_pid > 0) {
                        if (kill_and_sigcont(s->control_pid, sig) < 0 && errno != ESRCH)

                                log_warning("Failed to kill control process %li: %m", (long) s->control_pid);
                        else
                                wait_for_exit = true;
                }

                if (s->exec_context.kill_mode == KILL_CONTROL_GROUP) {

                        if (!(pid_set = set_new(trivial_hash_func, trivial_compare_func))) {
                                r = -ENOMEM;
                                goto fail;
                        }

                        /* Exclude the control pid from being killed via the cgroup */
                        if (s->control_pid > 0)
                                if ((r = set_put(pid_set, LONG_TO_PTR(s->control_pid))) < 0)
                                        goto fail;

                        if ((r = cgroup_bonding_kill_list(UNIT(s)->cgroup_bondings, sig, true, pid_set)) < 0) {
                                if (r != -EAGAIN && r != -ESRCH && r != -ENOENT)
                                        log_warning("Failed to kill control group: %s", strerror(-r));
                        } else if (r > 0)
                                wait_for_exit = true;

                        set_free(pid_set);
                        pid_set = NULL;
                }
        }

        if (wait_for_exit) {
                if ((r = unit_watch_timer(UNIT(s), s->timeout_usec, &s->timer_watch)) < 0)
                        goto fail;

                socket_set_state(s, state);
        } else if (state == SOCKET_STOP_PRE_SIGTERM || state == SOCKET_STOP_PRE_SIGKILL)
                socket_enter_stop_post(s, SOCKET_SUCCESS);
        else
                socket_enter_dead(s, SOCKET_SUCCESS);

        return;

fail:
        log_warning("%s failed to kill processes: %s", UNIT(s)->id, strerror(-r));

        if (state == SOCKET_STOP_PRE_SIGTERM || state == SOCKET_STOP_PRE_SIGKILL)
                socket_enter_stop_post(s, SOCKET_FAILURE_RESOURCES);
        else
                socket_enter_dead(s, SOCKET_FAILURE_RESOURCES);

        if (pid_set)
                set_free(pid_set);
}

static void socket_enter_stop_pre(Socket *s, SocketResult f) {
        int r;
        assert(s);

        if (f != SOCKET_SUCCESS)
                s->result = f;

        socket_unwatch_control_pid(s);

        s->control_command_id = SOCKET_EXEC_STOP_PRE;

        if ((s->control_command = s->exec_command[SOCKET_EXEC_STOP_PRE])) {
                if ((r = socket_spawn(s, s->control_command, &s->control_pid)) < 0)
                        goto fail;

                socket_set_state(s, SOCKET_STOP_PRE);
        } else
                socket_enter_stop_post(s, SOCKET_SUCCESS);

        return;

fail:
        log_warning("%s failed to run 'stop-pre' task: %s", UNIT(s)->id, strerror(-r));
        socket_enter_stop_post(s, SOCKET_FAILURE_RESOURCES);
}

static void socket_enter_listening(Socket *s) {
        int r;
        assert(s);

        r = socket_watch_fds(s);
        if (r < 0) {
                log_warning("%s failed to watch sockets: %s", UNIT(s)->id, strerror(-r));
                goto fail;
        }

        socket_set_state(s, SOCKET_LISTENING);
        return;

fail:
        socket_enter_stop_pre(s, SOCKET_FAILURE_RESOURCES);
}

static void socket_enter_start_post(Socket *s) {
        int r;
        assert(s);

        r = socket_open_fds(s);
        if (r < 0) {
                log_warning("%s failed to listen on sockets: %s", UNIT(s)->id, strerror(-r));
                goto fail;
        }

        socket_unwatch_control_pid(s);

        s->control_command_id = SOCKET_EXEC_START_POST;

        if ((s->control_command = s->exec_command[SOCKET_EXEC_START_POST])) {
                r = socket_spawn(s, s->control_command, &s->control_pid);
                if (r < 0) {
                        log_warning("%s failed to run 'start-post' task: %s", UNIT(s)->id, strerror(-r));
                        goto fail;
                }

                socket_set_state(s, SOCKET_START_POST);
        } else
                socket_enter_listening(s);

        return;

fail:
        socket_enter_stop_pre(s, SOCKET_FAILURE_RESOURCES);
}

static void socket_enter_start_pre(Socket *s) {
        int r;
        assert(s);

        socket_unwatch_control_pid(s);

        s->control_command_id = SOCKET_EXEC_START_PRE;

        if ((s->control_command = s->exec_command[SOCKET_EXEC_START_PRE])) {
                if ((r = socket_spawn(s, s->control_command, &s->control_pid)) < 0)
                        goto fail;

                socket_set_state(s, SOCKET_START_PRE);
        } else
                socket_enter_start_post(s);

        return;

fail:
        log_warning("%s failed to run 'start-pre' task: %s", UNIT(s)->id, strerror(-r));
        socket_enter_dead(s, SOCKET_FAILURE_RESOURCES);
}

static void socket_enter_running(Socket *s, int cfd) {
        int r;
        DBusError error;

        assert(s);
        dbus_error_init(&error);

        /* We don't take connections anymore if we are supposed to
         * shut down anyway */
        if (unit_pending_inactive(UNIT(s))) {
                log_debug("Suppressing connection request on %s since unit stop is scheduled.", UNIT(s)->id);

                if (cfd >= 0)
                        close_nointr_nofail(cfd);
                else  {
                        /* Flush all sockets by closing and reopening them */
                        socket_close_fds(s);

                        r = socket_watch_fds(s);
                        if (r < 0) {
                                log_warning("%s failed to watch sockets: %s", UNIT(s)->id, strerror(-r));
                                socket_enter_stop_pre(s, SOCKET_FAILURE_RESOURCES);
                        }
                }

                return;
        }

        if (cfd < 0) {
                Iterator i;
                Unit *u;
                bool pending = false;

                /* If there's already a start pending don't bother to
                 * do anything */
                SET_FOREACH(u, UNIT(s)->dependencies[UNIT_TRIGGERS], i)
                        if (unit_pending_active(u)) {
                                pending = true;
                                break;
                        }

                if (!pending) {
                        r = manager_add_job(UNIT(s)->manager, JOB_START, UNIT_DEREF(s->service), JOB_REPLACE, true, &error, NULL);
                        if (r < 0)
                                goto fail;
                }

                socket_set_state(s, SOCKET_RUNNING);
        } else {
                char *prefix, *instance = NULL, *name;
                Service *service;

                if (s->n_connections >= s->max_connections) {
                        log_warning("Too many incoming connections (%u)", s->n_connections);
                        close_nointr_nofail(cfd);
                        return;
                }

                r = socket_instantiate_service(s);
                if (r < 0)
                        goto fail;

                r = instance_from_socket(cfd, s->n_accepted, &instance);
                if (r < 0) {
                        if (r != -ENOTCONN)
                                goto fail;

                        /* ENOTCONN is legitimate if TCP RST was received.
                         * This connection is over, but the socket unit lives on. */
                        close_nointr_nofail(cfd);
                        return;
                }

                prefix = unit_name_to_prefix(UNIT(s)->id);
                if (!prefix) {
                        free(instance);
                        r = -ENOMEM;
                        goto fail;
                }

                name = unit_name_build(prefix, instance, ".service");
                free(prefix);
                free(instance);

                if (!name) {
                        r = -ENOMEM;
                        goto fail;
                }

                r = unit_add_name(UNIT_DEREF(s->service), name);
                if (r < 0) {
                        free(name);
                        goto fail;
                }

                service = SERVICE(UNIT_DEREF(s->service));
                unit_ref_unset(&s->service);
                s->n_accepted ++;

                UNIT(service)->no_gc = false;

                unit_choose_id(UNIT(service), name);
                free(name);

                r = service_set_socket_fd(service, cfd, s);
                if (r < 0)
                        goto fail;

                cfd = -1;
                s->n_connections ++;

                r = manager_add_job(UNIT(s)->manager, JOB_START, UNIT(service), JOB_REPLACE, true, &error, NULL);
                if (r < 0)
                        goto fail;

                /* Notify clients about changed counters */
                unit_add_to_dbus_queue(UNIT(s));
        }

        return;

fail:
        log_warning("%s failed to queue socket startup job: %s", UNIT(s)->id, bus_error(&error, r));

        if (cfd >= 0)
                close_nointr_nofail(cfd);

        dbus_error_free(&error);
}

static void socket_run_next(Socket *s) {
        int r;

        assert(s);
        assert(s->control_command);
        assert(s->control_command->command_next);

        socket_unwatch_control_pid(s);

        s->control_command = s->control_command->command_next;

        if ((r = socket_spawn(s, s->control_command, &s->control_pid)) < 0)
                goto fail;

        return;

fail:
        log_warning("%s failed to run next task: %s", UNIT(s)->id, strerror(-r));

        if (s->state == SOCKET_START_POST)
                socket_enter_stop_pre(s, SOCKET_FAILURE_RESOURCES);
        else if (s->state == SOCKET_STOP_POST)
                socket_enter_dead(s, SOCKET_FAILURE_RESOURCES);
        else
                socket_enter_signal(s, SOCKET_FINAL_SIGTERM, SOCKET_FAILURE_RESOURCES);
}

static int socket_start(Unit *u) {
        Socket *s = SOCKET(u);

        assert(s);

        /* We cannot fulfill this request right now, try again later
         * please! */
        if (s->state == SOCKET_STOP_PRE ||
            s->state == SOCKET_STOP_PRE_SIGKILL ||
            s->state == SOCKET_STOP_PRE_SIGTERM ||
            s->state == SOCKET_STOP_POST ||
            s->state == SOCKET_FINAL_SIGTERM ||
            s->state == SOCKET_FINAL_SIGKILL)
                return -EAGAIN;

        if (s->state == SOCKET_START_PRE ||
            s->state == SOCKET_START_POST)
                return 0;

        /* Cannot run this without the service being around */
        if (UNIT_DEREF(s->service)) {
                Service *service;

                service = SERVICE(UNIT_DEREF(s->service));

                if (UNIT(service)->load_state != UNIT_LOADED) {
                        log_error("Socket service %s not loaded, refusing.", UNIT(service)->id);
                        return -ENOENT;
                }

                /* If the service is already active we cannot start the
                 * socket */
                if (service->state != SERVICE_DEAD &&
                    service->state != SERVICE_FAILED &&
                    service->state != SERVICE_AUTO_RESTART) {
                        log_error("Socket service %s already active, refusing.", UNIT(service)->id);
                        return -EBUSY;
                }

#ifdef HAVE_SYSV_COMPAT
                if (service->sysv_path) {
                        log_error("Using SysV services for socket activation is not supported. Refusing.");
                        return -ENOENT;
                }
#endif
        }

        assert(s->state == SOCKET_DEAD || s->state == SOCKET_FAILED);

        s->result = SOCKET_SUCCESS;
        socket_enter_start_pre(s);
        return 0;
}

static int socket_stop(Unit *u) {
        Socket *s = SOCKET(u);

        assert(s);

        /* Already on it */
        if (s->state == SOCKET_STOP_PRE ||
            s->state == SOCKET_STOP_PRE_SIGTERM ||
            s->state == SOCKET_STOP_PRE_SIGKILL ||
            s->state == SOCKET_STOP_POST ||
            s->state == SOCKET_FINAL_SIGTERM ||
            s->state == SOCKET_FINAL_SIGKILL)
                return 0;

        /* If there's already something running we go directly into
         * kill mode. */
        if (s->state == SOCKET_START_PRE ||
            s->state == SOCKET_START_POST) {
                socket_enter_signal(s, SOCKET_STOP_PRE_SIGTERM, SOCKET_SUCCESS);
                return -EAGAIN;
        }

        assert(s->state == SOCKET_LISTENING || s->state == SOCKET_RUNNING);

        socket_enter_stop_pre(s, SOCKET_SUCCESS);
        return 0;
}

static int socket_serialize(Unit *u, FILE *f, FDSet *fds) {
        Socket *s = SOCKET(u);
        SocketPort *p;
        int r;

        assert(u);
        assert(f);
        assert(fds);

        unit_serialize_item(u, f, "state", socket_state_to_string(s->state));
        unit_serialize_item(u, f, "result", socket_result_to_string(s->result));
        unit_serialize_item_format(u, f, "n-accepted", "%u", s->n_accepted);

        if (s->control_pid > 0)
                unit_serialize_item_format(u, f, "control-pid", "%lu", (unsigned long) s->control_pid);

        if (s->control_command_id >= 0)
                unit_serialize_item(u, f, "control-command", socket_exec_command_to_string(s->control_command_id));

        LIST_FOREACH(port, p, s->ports) {
                int copy;

                if (p->fd < 0)
                        continue;

                if ((copy = fdset_put_dup(fds, p->fd)) < 0)
                        return copy;

                if (p->type == SOCKET_SOCKET) {
                        char *t;

                        if ((r = socket_address_print(&p->address, &t)) < 0)
                                return r;

                        if (socket_address_family(&p->address) == AF_NETLINK)
                                unit_serialize_item_format(u, f, "netlink", "%i %s", copy, t);
                        else
                                unit_serialize_item_format(u, f, "socket", "%i %i %s", copy, p->address.type, t);
                        free(t);
                } else if (p->type == SOCKET_SPECIAL)
                        unit_serialize_item_format(u, f, "special", "%i %s", copy, p->path);
                else {
                        assert(p->type == SOCKET_FIFO);
                        unit_serialize_item_format(u, f, "fifo", "%i %s", copy, p->path);
                }
        }

        return 0;
}

static int socket_deserialize_item(Unit *u, const char *key, const char *value, FDSet *fds) {
        Socket *s = SOCKET(u);

        assert(u);
        assert(key);
        assert(value);
        assert(fds);

        if (streq(key, "state")) {
                SocketState state;

                if ((state = socket_state_from_string(value)) < 0)
                        log_debug("Failed to parse state value %s", value);
                else
                        s->deserialized_state = state;
        } else if (streq(key, "result")) {
                SocketResult f;

                f = socket_result_from_string(value);
                if (f < 0)
                        log_debug("Failed to parse result value %s", value);
                else if (f != SOCKET_SUCCESS)
                        s->result = f;

        } else if (streq(key, "n-accepted")) {
                unsigned k;

                if (safe_atou(value, &k) < 0)
                        log_debug("Failed to parse n-accepted value %s", value);
                else
                        s->n_accepted += k;
        } else if (streq(key, "control-pid")) {
                pid_t pid;

                if (parse_pid(value, &pid) < 0)
                        log_debug("Failed to parse control-pid value %s", value);
                else
                        s->control_pid = pid;
        } else if (streq(key, "control-command")) {
                SocketExecCommand id;

                if ((id = socket_exec_command_from_string(value)) < 0)
                        log_debug("Failed to parse exec-command value %s", value);
                else {
                        s->control_command_id = id;
                        s->control_command = s->exec_command[id];
                }
        } else if (streq(key, "fifo")) {
                int fd, skip = 0;
                SocketPort *p;

                if (sscanf(value, "%i %n", &fd, &skip) < 1 || fd < 0 || !fdset_contains(fds, fd))
                        log_debug("Failed to parse fifo value %s", value);
                else {

                        LIST_FOREACH(port, p, s->ports)
                                if (p->type == SOCKET_FIFO &&
                                    streq_ptr(p->path, value+skip))
                                        break;

                        if (p) {
                                if (p->fd >= 0)
                                        close_nointr_nofail(p->fd);
                                p->fd = fdset_remove(fds, fd);
                        }
                }

        } else if (streq(key, "special")) {
                int fd, skip = 0;
                SocketPort *p;

                if (sscanf(value, "%i %n", &fd, &skip) < 1 || fd < 0 || !fdset_contains(fds, fd))
                        log_debug("Failed to parse special value %s", value);
                else {

                        LIST_FOREACH(port, p, s->ports)
                                if (p->type == SOCKET_SPECIAL &&
                                    streq_ptr(p->path, value+skip))
                                        break;

                        if (p) {
                                if (p->fd >= 0)
                                        close_nointr_nofail(p->fd);
                                p->fd = fdset_remove(fds, fd);
                        }
                }

        } else if (streq(key, "socket")) {
                int fd, type, skip = 0;
                SocketPort *p;

                if (sscanf(value, "%i %i %n", &fd, &type, &skip) < 2 || fd < 0 || type < 0 || !fdset_contains(fds, fd))
                        log_debug("Failed to parse socket value %s", value);
                else {

                        LIST_FOREACH(port, p, s->ports)
                                if (socket_address_is(&p->address, value+skip, type))
                                        break;

                        if (p) {
                                if (p->fd >= 0)
                                        close_nointr_nofail(p->fd);
                                p->fd = fdset_remove(fds, fd);
                        }
                }

        } else if (streq(key, "netlink")) {
                int fd, skip = 0;
                SocketPort *p;

                if (sscanf(value, "%i %n", &fd, &skip) < 1 || fd < 0 || !fdset_contains(fds, fd))
                        log_debug("Failed to parse socket value %s", value);
                else {

                        LIST_FOREACH(port, p, s->ports)
                                if (socket_address_is_netlink(&p->address, value+skip))
                                        break;

                        if (p) {
                                if (p->fd >= 0)
                                        close_nointr_nofail(p->fd);
                                p->fd = fdset_remove(fds, fd);
                        }
                }

        } else
                log_debug("Unknown serialization key '%s'", key);

        return 0;
}

static UnitActiveState socket_active_state(Unit *u) {
        assert(u);

        return state_translation_table[SOCKET(u)->state];
}

static const char *socket_sub_state_to_string(Unit *u) {
        assert(u);

        return socket_state_to_string(SOCKET(u)->state);
}

static bool socket_check_gc(Unit *u) {
        Socket *s = SOCKET(u);

        assert(u);

        return s->n_connections > 0;
}

static void socket_fd_event(Unit *u, int fd, uint32_t events, Watch *w) {
        Socket *s = SOCKET(u);
        int cfd = -1;

        assert(s);
        assert(fd >= 0);

        if (s->state != SOCKET_LISTENING)
                return;

        log_debug("Incoming traffic on %s", u->id);

        if (events != EPOLLIN) {

                if (events & EPOLLHUP)
                        log_error("%s: Got POLLHUP on a listening socket. The service probably invoked shutdown() on it, and should better not do that.", u->id);
                else
                        log_error("%s: Got unexpected poll event (0x%x) on socket.", u->id, events);

                goto fail;
        }

        if (w->socket_accept) {
                for (;;) {

                        if ((cfd = accept4(fd, NULL, NULL, SOCK_NONBLOCK)) < 0) {

                                if (errno == EINTR)
                                        continue;

                                log_error("Failed to accept socket: %m");
                                goto fail;
                        }

                        break;
                }

                socket_apply_socket_options(s, cfd);
        }

        socket_enter_running(s, cfd);
        return;

fail:
        socket_enter_stop_pre(s, SOCKET_FAILURE_RESOURCES);
}

static void socket_sigchld_event(Unit *u, pid_t pid, int code, int status) {
        Socket *s = SOCKET(u);
        SocketResult f;

        assert(s);
        assert(pid >= 0);

        if (pid != s->control_pid)
                return;

        s->control_pid = 0;

        if (is_clean_exit(code, status))
                f = SOCKET_SUCCESS;
        else if (code == CLD_EXITED)
                f = SOCKET_FAILURE_EXIT_CODE;
        else if (code == CLD_KILLED)
                f = SOCKET_FAILURE_SIGNAL;
        else if (code == CLD_DUMPED)
                f = SOCKET_FAILURE_CORE_DUMP;
        else
                assert_not_reached("Unknown code");

        if (s->control_command) {
                exec_status_exit(&s->control_command->exec_status, &s->exec_context, pid, code, status);

                if (s->control_command->ignore)
                        f = SOCKET_SUCCESS;
        }

        log_full(f == SOCKET_SUCCESS ? LOG_DEBUG : LOG_NOTICE,
                 "%s control process exited, code=%s status=%i", u->id, sigchld_code_to_string(code), status);

        if (f != SOCKET_SUCCESS)
                s->result = f;

        if (s->control_command &&
            s->control_command->command_next &&
            f == SOCKET_SUCCESS) {

                log_debug("%s running next command for state %s", u->id, socket_state_to_string(s->state));
                socket_run_next(s);
        } else {
                s->control_command = NULL;
                s->control_command_id = _SOCKET_EXEC_COMMAND_INVALID;

                /* No further commands for this step, so let's figure
                 * out what to do next */

                log_debug("%s got final SIGCHLD for state %s", u->id, socket_state_to_string(s->state));

                switch (s->state) {

                case SOCKET_START_PRE:
                        if (f == SOCKET_SUCCESS)
                                socket_enter_start_post(s);
                        else
                                socket_enter_signal(s, SOCKET_FINAL_SIGTERM, f);
                        break;

                case SOCKET_START_POST:
                        if (f == SOCKET_SUCCESS)
                                socket_enter_listening(s);
                        else
                                socket_enter_stop_pre(s, f);
                        break;

                case SOCKET_STOP_PRE:
                case SOCKET_STOP_PRE_SIGTERM:
                case SOCKET_STOP_PRE_SIGKILL:
                        socket_enter_stop_post(s, f);
                        break;

                case SOCKET_STOP_POST:
                case SOCKET_FINAL_SIGTERM:
                case SOCKET_FINAL_SIGKILL:
                        socket_enter_dead(s, f);
                        break;

                default:
                        assert_not_reached("Uh, control process died at wrong time.");
                }
        }

        /* Notify clients about changed exit status */
        unit_add_to_dbus_queue(u);
}

static void socket_timer_event(Unit *u, uint64_t elapsed, Watch *w) {
        Socket *s = SOCKET(u);

        assert(s);
        assert(elapsed == 1);
        assert(w == &s->timer_watch);

        switch (s->state) {

        case SOCKET_START_PRE:
                log_warning("%s starting timed out. Terminating.", u->id);
                socket_enter_signal(s, SOCKET_FINAL_SIGTERM, SOCKET_FAILURE_TIMEOUT);
                break;

        case SOCKET_START_POST:
                log_warning("%s starting timed out. Stopping.", u->id);
                socket_enter_stop_pre(s, SOCKET_FAILURE_TIMEOUT);
                break;

        case SOCKET_STOP_PRE:
                log_warning("%s stopping timed out. Terminating.", u->id);
                socket_enter_signal(s, SOCKET_STOP_PRE_SIGTERM, SOCKET_FAILURE_TIMEOUT);
                break;

        case SOCKET_STOP_PRE_SIGTERM:
                if (s->exec_context.send_sigkill) {
                        log_warning("%s stopping timed out. Killing.", u->id);
                        socket_enter_signal(s, SOCKET_STOP_PRE_SIGKILL, SOCKET_FAILURE_TIMEOUT);
                } else {
                        log_warning("%s stopping timed out. Skipping SIGKILL. Ignoring.", u->id);
                        socket_enter_stop_post(s, SOCKET_FAILURE_TIMEOUT);
                }
                break;

        case SOCKET_STOP_PRE_SIGKILL:
                log_warning("%s still around after SIGKILL. Ignoring.", u->id);
                socket_enter_stop_post(s, SOCKET_FAILURE_TIMEOUT);
                break;

        case SOCKET_STOP_POST:
                log_warning("%s stopping timed out (2). Terminating.", u->id);
                socket_enter_signal(s, SOCKET_FINAL_SIGTERM, SOCKET_FAILURE_TIMEOUT);
                break;

        case SOCKET_FINAL_SIGTERM:
                if (s->exec_context.send_sigkill) {
                        log_warning("%s stopping timed out (2). Killing.", u->id);
                        socket_enter_signal(s, SOCKET_FINAL_SIGKILL, SOCKET_FAILURE_TIMEOUT);
                } else {
                        log_warning("%s stopping timed out (2). Skipping SIGKILL. Ignoring.", u->id);
                        socket_enter_dead(s, SOCKET_FAILURE_TIMEOUT);
                }
                break;

        case SOCKET_FINAL_SIGKILL:
                log_warning("%s still around after SIGKILL (2). Entering failed mode.", u->id);
                socket_enter_dead(s, SOCKET_FAILURE_TIMEOUT);
                break;

        default:
                assert_not_reached("Timeout at wrong time.");
        }
}

int socket_collect_fds(Socket *s, int **fds, unsigned *n_fds) {
        int *rfds;
        unsigned rn_fds, k;
        SocketPort *p;

        assert(s);
        assert(fds);
        assert(n_fds);

        /* Called from the service code for requesting our fds */

        rn_fds = 0;
        LIST_FOREACH(port, p, s->ports)
                if (p->fd >= 0)
                        rn_fds++;

        if (rn_fds <= 0) {
                *fds = NULL;
                *n_fds = 0;
                return 0;
        }

        if (!(rfds = new(int, rn_fds)))
                return -ENOMEM;

        k = 0;
        LIST_FOREACH(port, p, s->ports)
                if (p->fd >= 0)
                        rfds[k++] = p->fd;

        assert(k == rn_fds);

        *fds = rfds;
        *n_fds = rn_fds;

        return 0;
}

void socket_notify_service_dead(Socket *s, bool failed_permanent) {
        assert(s);

        /* The service is dead. Dang!
         *
         * This is strictly for one-instance-for-all-connections
         * services. */

        if (s->state == SOCKET_RUNNING) {
                log_debug("%s got notified about service death (failed permanently: %s)", UNIT(s)->id, yes_no(failed_permanent));
                if (failed_permanent)
                        socket_enter_stop_pre(s, SOCKET_FAILURE_SERVICE_FAILED_PERMANENT);
                else
                        socket_enter_listening(s);
        }
}

void socket_connection_unref(Socket *s) {
        assert(s);

        /* The service is dead. Yay!
         *
         * This is strictly for one-instance-per-connection
         * services. */

        assert(s->n_connections > 0);
        s->n_connections--;

        log_debug("%s: One connection closed, %u left.", UNIT(s)->id, s->n_connections);
}

static void socket_reset_failed(Unit *u) {
        Socket *s = SOCKET(u);

        assert(s);

        if (s->state == SOCKET_FAILED)
                socket_set_state(s, SOCKET_DEAD);

        s->result = SOCKET_SUCCESS;
}

static int socket_kill(Unit *u, KillWho who, KillMode mode, int signo, DBusError *error) {
        Socket *s = SOCKET(u);
        int r = 0;
        Set *pid_set = NULL;

        assert(s);

        if (who == KILL_MAIN) {
                dbus_set_error(error, BUS_ERROR_NO_SUCH_PROCESS, "Socket units have no main processes");
                return -ESRCH;
        }

        if (s->control_pid <= 0 && who == KILL_CONTROL) {
                dbus_set_error(error, BUS_ERROR_NO_SUCH_PROCESS, "No control process to kill");
                return -ESRCH;
        }

        if (who == KILL_CONTROL || who == KILL_ALL)
                if (s->control_pid > 0)
                        if (kill(s->control_pid, signo) < 0)
                                r = -errno;

        if (who == KILL_ALL && mode == KILL_CONTROL_GROUP) {
                int q;

                if (!(pid_set = set_new(trivial_hash_func, trivial_compare_func)))
                        return -ENOMEM;

                /* Exclude the control pid from being killed via the cgroup */
                if (s->control_pid > 0)
                        if ((q = set_put(pid_set, LONG_TO_PTR(s->control_pid))) < 0) {
                                r = q;
                                goto finish;
                        }

                if ((q = cgroup_bonding_kill_list(UNIT(s)->cgroup_bondings, signo, false, pid_set)) < 0)
                        if (q != -EAGAIN && q != -ESRCH && q != -ENOENT)
                                r = q;
        }

finish:
        if (pid_set)
                set_free(pid_set);

        return r;
}

static const char* const socket_state_table[_SOCKET_STATE_MAX] = {
        [SOCKET_DEAD] = "dead",
        [SOCKET_START_PRE] = "start-pre",
        [SOCKET_START_POST] = "start-post",
        [SOCKET_LISTENING] = "listening",
        [SOCKET_RUNNING] = "running",
        [SOCKET_STOP_PRE] = "stop-pre",
        [SOCKET_STOP_PRE_SIGTERM] = "stop-pre-sigterm",
        [SOCKET_STOP_PRE_SIGKILL] = "stop-pre-sigkill",
        [SOCKET_STOP_POST] = "stop-post",
        [SOCKET_FINAL_SIGTERM] = "final-sigterm",
        [SOCKET_FINAL_SIGKILL] = "final-sigkill",
        [SOCKET_FAILED] = "failed"
};

DEFINE_STRING_TABLE_LOOKUP(socket_state, SocketState);

static const char* const socket_exec_command_table[_SOCKET_EXEC_COMMAND_MAX] = {
        [SOCKET_EXEC_START_PRE] = "StartPre",
        [SOCKET_EXEC_START_POST] = "StartPost",
        [SOCKET_EXEC_STOP_PRE] = "StopPre",
        [SOCKET_EXEC_STOP_POST] = "StopPost"
};

DEFINE_STRING_TABLE_LOOKUP(socket_exec_command, SocketExecCommand);

static const char* const socket_result_table[_SOCKET_RESULT_MAX] = {
        [SOCKET_SUCCESS] = "success",
        [SOCKET_FAILURE_RESOURCES] = "resources",
        [SOCKET_FAILURE_TIMEOUT] = "timeout",
        [SOCKET_FAILURE_EXIT_CODE] = "exit-code",
        [SOCKET_FAILURE_SIGNAL] = "signal",
        [SOCKET_FAILURE_CORE_DUMP] = "core-dump",
        [SOCKET_FAILURE_SERVICE_FAILED_PERMANENT] = "service-failed-permanent"
};

DEFINE_STRING_TABLE_LOOKUP(socket_result, SocketResult);

const UnitVTable socket_vtable = {
        .suffix = ".socket",
        .object_size = sizeof(Socket),
        .sections =
                "Unit\0"
                "Socket\0"
                "Install\0",

        .init = socket_init,
        .done = socket_done,
        .load = socket_load,

        .kill = socket_kill,

        .coldplug = socket_coldplug,

        .dump = socket_dump,

        .start = socket_start,
        .stop = socket_stop,

        .serialize = socket_serialize,
        .deserialize_item = socket_deserialize_item,

        .active_state = socket_active_state,
        .sub_state_to_string = socket_sub_state_to_string,

        .check_gc = socket_check_gc,

        .fd_event = socket_fd_event,
        .sigchld_event = socket_sigchld_event,
        .timer_event = socket_timer_event,

        .reset_failed = socket_reset_failed,

        .bus_interface = "org.freedesktop.systemd1.Socket",
        .bus_message_handler = bus_socket_message_handler,
        .bus_invalidating_properties =  bus_socket_invalidating_properties
};