Adding upstream version 241.upstream/241upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 869 insertions, 0 deletions

diff --git a/src/tty-ask-password-agent/tty-ask-password-agent.c b/src/tty-ask-password-agent/tty-ask-password-agent.c
new file mode 100644
index 0000000..fc165ff
--- /dev/null
+++ b/src/tty-ask-password-agent/tty-ask-password-agent.c
@@ -0,0 +1,869 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
+/***
+  Copyright © 2015 Werner Fink
+***/
+
+#include <errno.h>
+#include <fcntl.h>
+#include <getopt.h>
+#include <poll.h>
+#include <signal.h>
+#include <stdbool.h>
+#include <stddef.h>
+#include <string.h>
+#include <sys/inotify.h>
+#include <sys/prctl.h>
+#include <sys/signalfd.h>
+#include <sys/socket.h>
+#include <sys/wait.h>
+#include <sys/un.h>
+#include <unistd.h>
+
+#include "alloc-util.h"
+#include "ask-password-api.h"
+#include "conf-parser.h"
+#include "def.h"
+#include "dirent-util.h"
+#include "exit-status.h"
+#include "fd-util.h"
+#include "fileio.h"
+#include "hashmap.h"
+#include "io-util.h"
+#include "macro.h"
+#include "main-func.h"
+#include "mkdir.h"
+#include "path-util.h"
+#include "pretty-print.h"
+#include "process-util.h"
+#include "signal-util.h"
+#include "socket-util.h"
+#include "string-util.h"
+#include "strv.h"
+#include "terminal-util.h"
+#include "util.h"
+#include "utmp-wtmp.h"
+
+static enum {
+        ACTION_LIST,
+        ACTION_QUERY,
+        ACTION_WATCH,
+        ACTION_WALL
+} arg_action = ACTION_QUERY;
+
+static bool arg_plymouth = false;
+static bool arg_console = false;
+static const char *arg_device = NULL;
+
+static int ask_password_plymouth(
+                const char *message,
+                usec_t until,
+                AskPasswordFlags flags,
+                const char *flag_file,
+                char ***ret) {
+
+        static const union sockaddr_union sa = PLYMOUTH_SOCKET;
+        _cleanup_close_ int fd = -1, notify = -1;
+        _cleanup_free_ char *packet = NULL;
+        ssize_t k;
+        int r, n;
+        struct pollfd pollfd[2] = {};
+        char buffer[LINE_MAX];
+        size_t p = 0;
+        enum {
+                POLL_SOCKET,
+                POLL_INOTIFY
+        };
+
+        assert(ret);
+
+        if (flag_file) {
+                notify = inotify_init1(IN_CLOEXEC|IN_NONBLOCK);
+                if (notify < 0)
+                        return -errno;
+
+                r = inotify_add_watch(notify, flag_file, IN_ATTRIB); /* for the link count */
+                if (r < 0)
+                        return -errno;
+        }
+
+        fd = socket(AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
+        if (fd < 0)
+                return -errno;
+
+        r = connect(fd, &sa.sa, SOCKADDR_UN_LEN(sa.un));
+        if (r < 0)
+                return -errno;
+
+        if (flags & ASK_PASSWORD_ACCEPT_CACHED) {
+                packet = strdup("c");
+                n = 1;
+        } else if (asprintf(&packet, "*\002%c%s%n", (int) (strlen(message) + 1), message, &n) < 0)
+                packet = NULL;
+        if (!packet)
+                return -ENOMEM;
+
+        r = loop_write(fd, packet, n + 1, true);
+        if (r < 0)
+                return r;
+
+        pollfd[POLL_SOCKET].fd = fd;
+        pollfd[POLL_SOCKET].events = POLLIN;
+        pollfd[POLL_INOTIFY].fd = notify;
+        pollfd[POLL_INOTIFY].events = POLLIN;
+
+        for (;;) {
+                int sleep_for = -1, j;
+
+                if (until > 0) {
+                        usec_t y;
+
+                        y = now(CLOCK_MONOTONIC);
+
+                        if (y > until) {
+                                r = -ETIME;
+                                goto finish;
+                        }
+
+                        sleep_for = (int) ((until - y) / USEC_PER_MSEC);
+                }
+
+                if (flag_file && access(flag_file, F_OK) < 0) {
+                        r = -errno;
+                        goto finish;
+                }
+
+                j = poll(pollfd, notify >= 0 ? 2 : 1, sleep_for);
+                if (j < 0) {
+                        if (errno == EINTR)
+                                continue;
+
+                        r = -errno;
+                        goto finish;
+                } else if (j == 0) {
+                        r = -ETIME;
+                        goto finish;
+                }
+
+                if (notify >= 0 && pollfd[POLL_INOTIFY].revents != 0)
+                        (void) flush_fd(notify);
+
+                if (pollfd[POLL_SOCKET].revents == 0)
+                        continue;
+
+                k = read(fd, buffer + p, sizeof(buffer) - p);
+                if (k < 0) {
+                        if (IN_SET(errno, EINTR, EAGAIN))
+                                continue;
+
+                        r = -errno;
+                        goto finish;
+                } else if (k == 0) {
+                        r = -EIO;
+                        goto finish;
+                }
+
+                p += k;
+
+                if (p < 1)
+                        continue;
+
+                if (buffer[0] == 5) {
+
+                        if (flags & ASK_PASSWORD_ACCEPT_CACHED) {
+                                /* Hmm, first try with cached
+                                 * passwords failed, so let's retry
+                                 * with a normal password request */
+                                packet = mfree(packet);
+
+                                if (asprintf(&packet, "*\002%c%s%n", (int) (strlen(message) + 1), message, &n) < 0) {
+                                        r = -ENOMEM;
+                                        goto finish;
+                                }
+
+                                r = loop_write(fd, packet, n+1, true);
+                                if (r < 0)
+                                        goto finish;
+
+                                flags &= ~ASK_PASSWORD_ACCEPT_CACHED;
+                                p = 0;
+                                continue;
+                        }
+
+                        /* No password, because UI not shown */
+                        r = -ENOENT;
+                        goto finish;
+
+                } else if (IN_SET(buffer[0], 2, 9)) {
+                        uint32_t size;
+                        char **l;
+
+                        /* One or more answers */
+                        if (p < 5)
+                                continue;
+
+                        memcpy(&size, buffer+1, sizeof(size));
+                        size = le32toh(size);
+                        if (size + 5 > sizeof(buffer)) {
+                                r = -EIO;
+                                goto finish;
+                        }
+
+                        if (p-5 < size)
+                                continue;
+
+                        l = strv_parse_nulstr(buffer + 5, size);
+                        if (!l) {
+                                r = -ENOMEM;
+                                goto finish;
+                        }
+
+                        *ret = l;
+                        break;
+
+                } else {
+                        /* Unknown packet */
+                        r = -EIO;
+                        goto finish;
+                }
+        }
+
+        r = 0;
+
+finish:
+        explicit_bzero_safe(buffer, sizeof(buffer));
+        return r;
+}
+
+static int send_passwords(const char *socket_name, char **passwords) {
+        _cleanup_free_ char *packet = NULL;
+        _cleanup_close_ int socket_fd = -1;
+        union sockaddr_union sa = {};
+        size_t packet_length = 1;
+        char **p, *d;
+        ssize_t n;
+        int r, salen;
+
+        assert(socket_name);
+
+        salen = sockaddr_un_set_path(&sa.un, socket_name);
+        if (salen < 0)
+                return salen;
+
+        STRV_FOREACH(p, passwords)
+                packet_length += strlen(*p) + 1;
+
+        packet = new(char, packet_length);
+        if (!packet)
+                return -ENOMEM;
+
+        packet[0] = '+';
+
+        d = packet + 1;
+        STRV_FOREACH(p, passwords)
+                d = stpcpy(d, *p) + 1;
+
+        socket_fd = socket(AF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC, 0);
+        if (socket_fd < 0) {
+                r = log_debug_errno(errno, "socket(): %m");
+                goto finish;
+        }
+
+        n = sendto(socket_fd, packet, packet_length, MSG_NOSIGNAL, &sa.sa, salen);
+        if (n < 0) {
+                r = log_debug_errno(errno, "sendto(): %m");
+                goto finish;
+        }
+
+        r = (int) n;
+
+finish:
+        explicit_bzero_safe(packet, packet_length);
+        return r;
+}
+
+static int parse_password(const char *filename, char **wall) {
+        _cleanup_free_ char *socket_name = NULL, *message = NULL;
+        bool accept_cached = false, echo = false;
+        uint64_t not_after = 0;
+        unsigned pid = 0;
+
+        const ConfigTableItem items[] = {
+                { "Ask", "Socket",       config_parse_string,   0, &socket_name   },
+                { "Ask", "NotAfter",     config_parse_uint64,   0, &not_after     },
+                { "Ask", "Message",      config_parse_string,   0, &message       },
+                { "Ask", "PID",          config_parse_unsigned, 0, &pid           },
+                { "Ask", "AcceptCached", config_parse_bool,     0, &accept_cached },
+                { "Ask", "Echo",         config_parse_bool,     0, &echo          },
+                {}
+        };
+
+        int r;
+
+        assert(filename);
+
+        r = config_parse(NULL, filename, NULL,
+                         NULL,
+                         config_item_table_lookup, items,
+                         CONFIG_PARSE_RELAXED|CONFIG_PARSE_WARN, NULL);
+        if (r < 0)
+                return r;
+
+        if (!socket_name)
+                return log_error_errno(SYNTHETIC_ERRNO(EBADMSG),
+                                       "Invalid password file %s", filename);
+
+        if (not_after > 0 && now(CLOCK_MONOTONIC) > not_after)
+                return 0;
+
+        if (pid > 0 && !pid_is_alive(pid))
+                return 0;
+
+        if (arg_action == ACTION_LIST)
+                printf("'%s' (PID %u)\n", message, pid);
+
+        else if (arg_action == ACTION_WALL) {
+                char *_wall;
+
+                if (asprintf(&_wall,
+                             "%s%sPassword entry required for \'%s\' (PID %u).\r\n"
+                             "Please enter password with the systemd-tty-ask-password-agent tool:",
+                             strempty(*wall),
+                             *wall ? "\r\n\r\n" : "",
+                             message,
+                             pid) < 0)
+                        return log_oom();
+
+                free(*wall);
+                *wall = _wall;
+
+        } else {
+                _cleanup_strv_free_erase_ char **passwords = NULL;
+
+                assert(IN_SET(arg_action, ACTION_QUERY, ACTION_WATCH));
+
+                if (access(socket_name, W_OK) < 0) {
+                        if (arg_action == ACTION_QUERY)
+                                log_info("Not querying '%s' (PID %u), lacking privileges.", message, pid);
+
+                        return 0;
+                }
+
+                if (arg_plymouth)
+                        r = ask_password_plymouth(message, not_after, accept_cached ? ASK_PASSWORD_ACCEPT_CACHED : 0, filename, &passwords);
+                else {
+                        int tty_fd = -1;
+
+                        if (arg_console) {
+                                const char *con = arg_device ?: "/dev/console";
+
+                                tty_fd = acquire_terminal(con, ACQUIRE_TERMINAL_WAIT, USEC_INFINITY);
+                                if (tty_fd < 0)
+                                        return log_error_errno(tty_fd, "Failed to acquire %s: %m", con);
+
+                                r = reset_terminal_fd(tty_fd, true);
+                                if (r < 0)
+                                        log_warning_errno(r, "Failed to reset terminal, ignoring: %m");
+                        }
+
+                        r = ask_password_tty(tty_fd, message, NULL, not_after,
+                                             (echo ? ASK_PASSWORD_ECHO : 0) |
+                                             (arg_console ? ASK_PASSWORD_CONSOLE_COLOR : 0),
+                                             filename, &passwords);
+
+                        if (arg_console) {
+                                tty_fd = safe_close(tty_fd);
+                                release_terminal();
+                        }
+                }
+
+                /* If the query went away, that's OK */
+                if (IN_SET(r, -ETIME, -ENOENT))
+                        return 0;
+
+                if (r < 0)
+                        return log_error_errno(r, "Failed to query password: %m");
+
+                r = send_passwords(socket_name, passwords);
+                if (r < 0)
+                        return log_error_errno(r, "Failed to send: %m");
+        }
+
+        return 0;
+}
+
+static int wall_tty_block(void) {
+        _cleanup_free_ char *p = NULL;
+        dev_t devnr;
+        int fd, r;
+
+        r = get_ctty_devnr(0, &devnr);
+        if (r == -ENXIO) /* We have no controlling tty */
+                return -ENOTTY;
+        if (r < 0)
+                return log_error_errno(r, "Failed to get controlling TTY: %m");
+
+        if (asprintf(&p, "/run/systemd/ask-password-block/%u:%u", major(devnr), minor(devnr)) < 0)
+                return log_oom();
+
+        (void) mkdir_parents_label(p, 0700);
+        (void) mkfifo(p, 0600);
+
+        fd = open(p, O_RDONLY|O_CLOEXEC|O_NONBLOCK|O_NOCTTY);
+        if (fd < 0)
+                return log_debug_errno(errno, "Failed to open %s: %m", p);
+
+        return fd;
+}
+
+static bool wall_tty_match(const char *path, void *userdata) {
+        _cleanup_free_ char *p = NULL;
+        _cleanup_close_ int fd = -1;
+        struct stat st;
+
+        if (!path_is_absolute(path))
+                path = strjoina("/dev/", path);
+
+        if (lstat(path, &st) < 0) {
+                log_debug_errno(errno, "Failed to stat %s: %m", path);
+                return true;
+        }
+
+        if (!S_ISCHR(st.st_mode)) {
+                log_debug("%s is not a character device.", path);
+                return true;
+        }
+
+        /* We use named pipes to ensure that wall messages suggesting
+         * password entry are not printed over password prompts
+         * already shown. We use the fact here that opening a pipe in
+         * non-blocking mode for write-only will succeed only if
+         * there's some writer behind it. Using pipes has the
+         * advantage that the block will automatically go away if the
+         * process dies. */
+
+        if (asprintf(&p, "/run/systemd/ask-password-block/%u:%u", major(st.st_rdev), minor(st.st_rdev)) < 0) {
+                log_oom();
+                return true;
+        }
+
+        fd = open(p, O_WRONLY|O_CLOEXEC|O_NONBLOCK|O_NOCTTY);
+        if (fd < 0) {
+                log_debug_errno(errno, "Failed to open the wall pipe: %m");
+                return 1;
+        }
+
+        /* What, we managed to open the pipe? Then this tty is filtered. */
+        return 0;
+}
+
+static int show_passwords(void) {
+        _cleanup_closedir_ DIR *d;
+        struct dirent *de;
+        int r = 0;
+
+        d = opendir("/run/systemd/ask-password");
+        if (!d) {
+                if (errno == ENOENT)
+                        return 0;
+
+                return log_error_errno(errno, "Failed to open /run/systemd/ask-password: %m");
+        }
+
+        FOREACH_DIRENT_ALL(de, d, return log_error_errno(errno, "Failed to read directory: %m")) {
+                _cleanup_free_ char *p = NULL, *wall = NULL;
+                int q;
+
+                /* We only support /dev on tmpfs, hence we can rely on
+                 * d_type to be reliable */
+
+                if (de->d_type != DT_REG)
+                        continue;
+
+                if (hidden_or_backup_file(de->d_name))
+                        continue;
+
+                if (!startswith(de->d_name, "ask."))
+                        continue;
+
+                p = strappend("/run/systemd/ask-password/", de->d_name);
+                if (!p)
+                        return log_oom();
+
+                q = parse_password(p, &wall);
+                if (q < 0 && r == 0)
+                        r = q;
+
+                if (wall)
+                        (void) utmp_wall(wall, NULL, NULL, wall_tty_match, NULL);
+        }
+
+        return r;
+}
+
+static int watch_passwords(void) {
+        enum {
+                FD_INOTIFY,
+                FD_SIGNAL,
+                _FD_MAX
+        };
+
+        _cleanup_close_ int notify = -1, signal_fd = -1, tty_block_fd = -1;
+        struct pollfd pollfd[_FD_MAX] = {};
+        sigset_t mask;
+        int r;
+
+        tty_block_fd = wall_tty_block();
+
+        (void) mkdir_p_label("/run/systemd/ask-password", 0755);
+
+        notify = inotify_init1(IN_CLOEXEC);
+        if (notify < 0)
+                return log_error_errno(errno, "Failed to allocate directory watch: %m");
+
+        if (inotify_add_watch(notify, "/run/systemd/ask-password", IN_CLOSE_WRITE|IN_MOVED_TO) < 0) {
+                if (errno == ENOSPC)
+                        return log_error_errno(errno, "Failed to add /run/systemd/ask-password to directory watch: inotify watch limit reached");
+                else
+                        return log_error_errno(errno, "Failed to add /run/systemd/ask-password to directory watch: %m");
+        }
+
+        assert_se(sigemptyset(&mask) >= 0);
+        assert_se(sigset_add_many(&mask, SIGINT, SIGTERM, -1) >= 0);
+        assert_se(sigprocmask(SIG_SETMASK, &mask, NULL) >= 0);
+
+        signal_fd = signalfd(-1, &mask, SFD_NONBLOCK|SFD_CLOEXEC);
+        if (signal_fd < 0)
+                return log_error_errno(errno, "Failed to allocate signal file descriptor: %m");
+
+        pollfd[FD_INOTIFY].fd = notify;
+        pollfd[FD_INOTIFY].events = POLLIN;
+        pollfd[FD_SIGNAL].fd = signal_fd;
+        pollfd[FD_SIGNAL].events = POLLIN;
+
+        for (;;) {
+                r = show_passwords();
+                if (r < 0)
+                        log_error_errno(r, "Failed to show password: %m");
+
+                if (poll(pollfd, _FD_MAX, -1) < 0) {
+                        if (errno == EINTR)
+                                continue;
+
+                        return -errno;
+                }
+
+                if (pollfd[FD_INOTIFY].revents != 0)
+                        (void) flush_fd(notify);
+
+                if (pollfd[FD_SIGNAL].revents != 0)
+                        break;
+        }
+
+        return 0;
+}
+
+static int help(void) {
+        _cleanup_free_ char *link = NULL;
+        int r;
+
+        r = terminal_urlify_man("systemd-tty-ask-password-agent", "1", &link);
+        if (r < 0)
+                return log_oom();
+
+        printf("%s [OPTIONS...]\n\n"
+               "Process system password requests.\n\n"
+               "  -h --help     Show this help\n"
+               "     --version  Show package version\n"
+               "     --list     Show pending password requests\n"
+               "     --query    Process pending password requests\n"
+               "     --watch    Continuously process password requests\n"
+               "     --wall     Continuously forward password requests to wall\n"
+               "     --plymouth Ask question with Plymouth instead of on TTY\n"
+               "     --console  Ask question on /dev/console instead of current TTY\n"
+               "\nSee the %s for details.\n"
+               , program_invocation_short_name
+               , link
+        );
+
+        return 0;
+}
+
+static int parse_argv(int argc, char *argv[]) {
+
+        enum {
+                ARG_LIST = 0x100,
+                ARG_QUERY,
+                ARG_WATCH,
+                ARG_WALL,
+                ARG_PLYMOUTH,
+                ARG_CONSOLE,
+                ARG_VERSION
+        };
+
+        static const struct option options[] = {
+                { "help",     no_argument,       NULL, 'h'          },
+                { "version",  no_argument,       NULL, ARG_VERSION  },
+                { "list",     no_argument,       NULL, ARG_LIST     },
+                { "query",    no_argument,       NULL, ARG_QUERY    },
+                { "watch",    no_argument,       NULL, ARG_WATCH    },
+                { "wall",     no_argument,       NULL, ARG_WALL     },
+                { "plymouth", no_argument,       NULL, ARG_PLYMOUTH },
+                { "console",  optional_argument, NULL, ARG_CONSOLE  },
+                {}
+        };
+
+        int c;
+
+        assert(argc >= 0);
+        assert(argv);
+
+        while ((c = getopt_long(argc, argv, "h", options, NULL)) >= 0)
+
+                switch (c) {
+
+                case 'h':
+                        return help();
+
+                case ARG_VERSION:
+                        return version();
+
+                case ARG_LIST:
+                        arg_action = ACTION_LIST;
+                        break;
+
+                case ARG_QUERY:
+                        arg_action = ACTION_QUERY;
+                        break;
+
+                case ARG_WATCH:
+                        arg_action = ACTION_WATCH;
+                        break;
+
+                case ARG_WALL:
+                        arg_action = ACTION_WALL;
+                        break;
+
+                case ARG_PLYMOUTH:
+                        arg_plymouth = true;
+                        break;
+
+                case ARG_CONSOLE:
+                        arg_console = true;
+                        if (optarg) {
+
+                                if (isempty(optarg))
+                                        return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
+                                                               "Empty console device path is not allowed.");
+
+                                arg_device = optarg;
+                        }
+                        break;
+
+                case '?':
+                        return -EINVAL;
+
+                default:
+                        assert_not_reached("Unhandled option");
+                }
+
+        if (optind != argc)
+                return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
+                                       "%s takes no arguments.", program_invocation_short_name);
+
+        if (arg_plymouth || arg_console) {
+
+                if (!IN_SET(arg_action, ACTION_QUERY, ACTION_WATCH))
+                        return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
+                                               "Options --query and --watch conflict.");
+
+                if (arg_plymouth && arg_console)
+                        return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
+                                               "Options --plymouth and --console conflict.");
+        }
+
+        return 1;
+}
+
+/*
+ * To be able to ask on all terminal devices of /dev/console
+ * the devices are collected. If more than one device is found,
+ * then on each of the terminals a inquiring task is forked.
+ * Every task has its own session and its own controlling terminal.
+ * If one of the tasks does handle a password, the remaining tasks
+ * will be terminated.
+ */
+static int ask_on_this_console(const char *tty, pid_t *ret_pid, int argc, char *argv[]) {
+        struct sigaction sig = {
+                .sa_handler = nop_signal_handler,
+                .sa_flags = SA_NOCLDSTOP | SA_RESTART,
+        };
+        pid_t pid;
+        int r;
+
+        assert_se(sigprocmask_many(SIG_UNBLOCK, NULL, SIGHUP, SIGCHLD, -1) >= 0);
+
+        assert_se(sigemptyset(&sig.sa_mask) >= 0);
+        assert_se(sigaction(SIGCHLD, &sig, NULL) >= 0);
+
+        sig.sa_handler = SIG_DFL;
+        assert_se(sigaction(SIGHUP, &sig, NULL) >= 0);
+
+        r = safe_fork("(sd-passwd)", FORK_RESET_SIGNALS|FORK_LOG, &pid);
+        if (r < 0)
+                return r;
+        if (r == 0) {
+                int ac;
+
+                assert_se(prctl(PR_SET_PDEATHSIG, SIGHUP) >= 0);
+
+                for (ac = 0; ac < argc; ac++) {
+                        if (streq(argv[ac], "--console")) {
+                                argv[ac] = strjoina("--console=", tty);
+                                break;
+                        }
+                }
+
+                assert(ac < argc);
+
+                execv(SYSTEMD_TTY_ASK_PASSWORD_AGENT_BINARY_PATH, argv);
+                _exit(EXIT_FAILURE);
+        }
+
+        *ret_pid = pid;
+        return 0;
+}
+
+static void terminate_agents(Set *pids) {
+        struct timespec ts;
+        siginfo_t status = {};
+        sigset_t set;
+        Iterator i;
+        void *p;
+        int r, signum;
+
+        /*
+         * Request termination of the remaining processes as those
+         * are not required anymore.
+         */
+        SET_FOREACH(p, pids, i)
+                (void) kill(PTR_TO_PID(p), SIGTERM);
+
+        /*
+         * Collect the processes which have go away.
+         */
+        assert_se(sigemptyset(&set) >= 0);
+        assert_se(sigaddset(&set, SIGCHLD) >= 0);
+        timespec_store(&ts, 50 * USEC_PER_MSEC);
+
+        while (!set_isempty(pids)) {
+
+                zero(status);
+                r = waitid(P_ALL, 0, &status, WEXITED|WNOHANG);
+                if (r < 0 && errno == EINTR)
+                        continue;
+
+                if (r == 0 && status.si_pid > 0) {
+                        set_remove(pids, PID_TO_PTR(status.si_pid));
+                        continue;
+                }
+
+                signum = sigtimedwait(&set, NULL, &ts);
+                if (signum < 0) {
+                        if (errno != EAGAIN)
+                                log_error_errno(errno, "sigtimedwait() failed: %m");
+                        break;
+                }
+                assert(signum == SIGCHLD);
+        }
+
+        /*
+         * Kill hanging processes.
+         */
+        SET_FOREACH(p, pids, i) {
+                log_warning("Failed to terminate child %d, killing it", PTR_TO_PID(p));
+                (void) kill(PTR_TO_PID(p), SIGKILL);
+        }
+}
+
+static int ask_on_consoles(int argc, char *argv[]) {
+        _cleanup_set_free_ Set *pids = NULL;
+        _cleanup_strv_free_ char **consoles = NULL;
+        siginfo_t status = {};
+        char **tty;
+        pid_t pid;
+        int r;
+
+        r = get_kernel_consoles(&consoles);
+        if (r < 0)
+                return log_error_errno(r, "Failed to determine devices of /dev/console: %m");
+
+        pids = set_new(NULL);
+        if (!pids)
+                return log_oom();
+
+        /* Start an agent on each console. */
+        STRV_FOREACH(tty, consoles) {
+                r = ask_on_this_console(*tty, &pid, argc, argv);
+                if (r < 0)
+                        return r;
+
+                if (set_put(pids, PID_TO_PTR(pid)) < 0)
+                        return log_oom();
+        }
+
+        /* Wait for an agent to exit. */
+        for (;;) {
+                zero(status);
+
+                if (waitid(P_ALL, 0, &status, WEXITED) < 0) {
+                        if (errno == EINTR)
+                                continue;
+
+                        return log_error_errno(errno, "waitid() failed: %m");
+                }
+
+                set_remove(pids, PID_TO_PTR(status.si_pid));
+                break;
+        }
+
+        if (!is_clean_exit(status.si_code, status.si_status, EXIT_CLEAN_DAEMON, NULL))
+                log_error("Password agent failed with: %d", status.si_status);
+
+        terminate_agents(pids);
+        return 0;
+}
+
+static int run(int argc, char *argv[]) {
+        int r;
+
+        log_setup_service();
+
+        umask(0022);
+
+        r = parse_argv(argc, argv);
+        if (r <= 0)
+                return r;
+
+        if (arg_console && !arg_device)
+                /*
+                 * Spawn a separate process for each console device.
+                 */
+                return ask_on_consoles(argc, argv);
+
+        if (arg_device) {
+                /*
+                 * Later on, a controlling terminal will be acquired,
+                 * therefore the current process has to become a session
+                 * leader and should not have a controlling terminal already.
+                 */
+                (void) setsid();
+                (void) release_terminal();
+        }
+
+        if (IN_SET(arg_action, ACTION_WATCH, ACTION_WALL))
+                return watch_passwords();
+        else
+                return show_passwords();
+}
+
+DEFINE_MAIN_FUNCTION(run);