fsckd daemon for inter-fsckd communication

Add systemd-fsckd multiplexer which accepts multiple systemd-fsck
instances to connect to it and sends progress report. systemd-fsckd then
computes and writes to /dev/console the number of devices currently being
checked and the minimum fsck progress. This will be used for interactive
progress report and cancelling in plymouth.

systemd-fsckd stops on idle when no systemd-fsck is connected.

Make the necessary changes to systemd-fsck to connect to the systemd-fsckd
socket.

3 files changed, 439 insertions, 0 deletions

diff --git a/src/fsckd/Makefile b/src/fsckd/Makefile
new file mode 120000
index 0000000000..d0b0e8e008
--- /dev/null
+++ b/src/fsckd/Makefile
@@ -0,0 +1 @@
+../Makefile
\ No newline at end of file
diff --git a/src/fsckd/fsckd.c b/src/fsckd/fsckd.c
new file mode 100644
index 0000000000..39fe899b99
--- /dev/null
+++ b/src/fsckd/fsckd.c
@@ -0,0 +1,404 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+/***
+  This file is part of systemd.
+
+  Copyright 2015 Canonical
+
+  Author:
+    Didier Roche <didrocks@ubuntu.com>
+
+  systemd is free software; you can redistribute it and/or modify it
+  under the terms of the GNU Lesser General Public License as published by
+  the Free Software Foundation; either version 2.1 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
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public License
+  along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include <getopt.h>
+#include <errno.h>
+#include <math.h>
+#include <stdbool.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <sys/socket.h>
+#include <sys/types.h>
+#include <sys/un.h>
+#include <unistd.h>
+
+#include "build.h"
+#include "event-util.h"
+#include "fsckd.h"
+#include "log.h"
+#include "list.h"
+#include "macro.h"
+#include "sd-daemon.h"
+#include "socket-util.h"
+#include "util.h"
+
+#define IDLE_TIME_SECONDS 30
+
+struct Manager;
+
+typedef struct Client {
+        struct Manager *manager;
+        int fd;
+        dev_t devnum;
+        size_t cur;
+        size_t max;
+        int pass;
+        double percent;
+        size_t buflen;
+
+        LIST_FIELDS(struct Client, clients);
+} Client;
+
+typedef struct Manager {
+        sd_event *event;
+        Client *clients;
+        int clear;
+        int connection_fd;
+        FILE *console;
+        double percent;
+        int numdevices;
+} Manager;
+
+static void manager_free(Manager *m);
+DEFINE_TRIVIAL_CLEANUP_FUNC(Manager*, manager_free);
+#define _cleanup_manager_free_ _cleanup_(manager_freep)
+
+static double compute_percent(int pass, size_t cur, size_t max) {
+        /* Values stolen from e2fsck */
+
+        static const double pass_table[] = {
+                0, 70, 90, 92, 95, 100
+        };
+
+        if (pass <= 0)
+                return 0.0;
+
+        if ((unsigned) pass >= ELEMENTSOF(pass_table) || max == 0)
+                return 100.0;
+
+        return pass_table[pass-1] +
+                (pass_table[pass] - pass_table[pass-1]) *
+                (double) cur / max;
+}
+
+
+static void remove_client(Client **first, Client *item) {
+        LIST_REMOVE(clients, *first, item);
+        safe_close(item->fd);
+        free(item);
+}
+
+static int update_global_progress(Manager *m) {
+        Client *current = NULL;
+        _cleanup_free_ char *console_message = NULL;
+        int current_numdevices = 0, l = 0;
+        double current_percent = 100;
+
+        /* get the overall percentage */
+        LIST_FOREACH(clients, current, m->clients) {
+                current_numdevices++;
+
+                /* right now, we only keep the minimum % of all fsckd processes. We could in the future trying to be
+                   linear, but max changes and corresponds to the pass. We have all the informations into fsckd
+                   already if we can treat that in a smarter way. */
+                current_percent = MIN(current_percent, current->percent);
+        }
+
+        /* update if there is anything user-visible to update */
+        if (fabs(current_percent - m->percent) > 0.001 || current_numdevices != m->numdevices) {
+                m->numdevices = current_numdevices;
+                m->percent = current_percent;
+
+                if (asprintf(&console_message, "Checking in progress on %d disks (%3.1f%% complete)",
+                                                m->numdevices, m->percent) < 0)
+                        return -ENOMEM;
+
+                /* write to console */
+                if (m->console) {
+                        fprintf(m->console, "\r%s\r%n", console_message, &l);
+                        fflush(m->console);
+                }
+
+                if (l > m->clear)
+                        m->clear = l;
+        }
+        return 0;
+}
+
+static int progress_handler(sd_event_source *s, int fd, uint32_t revents, void *userdata) {
+        Client *client = userdata;
+        Manager *m = NULL;
+        FsckProgress fsck_data;
+        size_t buflen;
+        int r;
+
+        assert(client);
+        m = client->manager;
+
+        /* ensure we have enough data to read */
+        r = ioctl(fd, FIONREAD, &buflen);
+        if (r == 0 && buflen != 0 && (size_t) buflen < sizeof(FsckProgress)) {
+                if (client->buflen != buflen)
+                        client->buflen = buflen;
+                /* we got twice the same size from a bad behaving client, kick it off the list */
+                else {
+                        log_warning("Closing bad behaving fsck client connection at fd %d", client->fd);
+                        remove_client(&(m->clients), client);
+                        r = update_global_progress(m);
+                        if (r < 0)
+                                log_warning_errno(r, "Couldn't update global progress: %m");
+                }
+                return 0;
+        }
+
+        /* read actual data */
+        r = recv(fd, &fsck_data, sizeof(FsckProgress), 0);
+        if (r == 0) {
+                log_debug("Fsck client connected to fd %d disconnected", client->fd);
+                remove_client(&(m->clients), client);
+        } else if (r > 0 && r != sizeof(FsckProgress))
+                log_warning("Unexpected data structure sent to fsckd socket from fd: %d. Ignoring", client->fd);
+        else if (r > 0 && r == sizeof(FsckProgress)) {
+                client->devnum = fsck_data.devnum;
+                client->cur = fsck_data.cur;
+                client->max = fsck_data.max;
+                client->pass = fsck_data.pass;
+                client->percent = compute_percent(client->pass, client->cur, client->max);
+                log_debug("Getting progress for %u:%u (%lu, %lu, %d) : %3.1f%%",
+                          major(client->devnum), minor(client->devnum),
+                          client->cur, client->max, client->pass, client->percent);
+        } else
+                log_error_errno(r, "Unknown error while trying to read fsck data: %m");
+
+        r = update_global_progress(m);
+        if (r < 0)
+                log_warning_errno(r, "Couldn't update global progress: %m");
+
+        return 0;
+}
+
+static int new_connection_handler(sd_event_source *s, int fd, uint32_t revents, void *userdata) {
+        Manager *m = userdata;
+        Client *client = NULL;
+        int new_client_fd, r;
+
+        assert(m);
+
+        /* Initialize and list new clients */
+        new_client_fd = accept4(m->connection_fd, NULL, NULL, SOCK_CLOEXEC);
+        if (new_client_fd > 0) {
+                log_debug("New fsck client connected to fd: %d", new_client_fd);
+                client = new0(Client, 1);
+                if (!client)
+                        return log_oom();
+                client->fd = new_client_fd;
+                client->manager = m;
+                LIST_PREPEND(clients, m->clients, client);
+                r = sd_event_add_io(m->event, NULL, client->fd, EPOLLIN, progress_handler, client);
+                if (r < 0) {
+                        remove_client(&(m->clients), client);
+                        return r;
+                }
+        } else
+                return log_error_errno(errno, "Couldn't accept a new connection: %m");
+
+        return 0;
+}
+
+static void manager_free(Manager *m) {
+        Client *current = NULL, *l = NULL;
+        if (!m)
+                return;
+
+        /* clear last line */
+        if (m->console && m->clear > 0) {
+                unsigned j;
+
+                fputc('\r', m->console);
+                for (j = 0; j < (unsigned) m->clear; j++)
+                        fputc(' ', m->console);
+                fputc('\r', m->console);
+                fflush(m->console);
+        }
+
+        safe_close(m->connection_fd);
+        if (m->console)
+                fclose(m->console);
+
+        LIST_FOREACH_SAFE(clients, current, l, m->clients)
+                remove_client(&(m->clients), current);
+
+        sd_event_unref(m->event);
+
+        free(m);
+}
+
+static int manager_new(Manager **ret, int fd) {
+        _cleanup_manager_free_ Manager *m = NULL;
+        int r;
+
+        assert(ret);
+
+        m = new0(Manager, 1);
+        if (!m)
+                return -ENOMEM;
+
+        r = sd_event_default(&m->event);
+        if (r < 0)
+                return r;
+
+        m->connection_fd = fd;
+        m->console = fopen("/dev/console", "we");
+        if (!m->console)
+                return log_warning_errno(errno, "Can't connect to /dev/console: %m");
+        m->percent = 100;
+
+        *ret = m;
+        m = NULL;
+
+        return 0;
+}
+
+static int run_event_loop_with_timeout(sd_event *e, usec_t timeout) {
+        int r, code;
+
+        assert(e);
+
+        for (;;) {
+                r = sd_event_get_state(e);
+                if (r < 0)
+                        return r;
+                if (r == SD_EVENT_FINISHED)
+                        break;
+
+                r = sd_event_run(e, timeout);
+                if (r < 0)
+                        return r;
+
+                /* timeout reached */
+                if (r == 0) {
+                        sd_event_exit(e, 0);
+                        break;
+                }
+        }
+
+        r = sd_event_get_exit_code(e, &code);
+        if (r < 0)
+                return r;
+
+        return code;
+}
+
+static void help(void) {
+        printf("%s [OPTIONS...]\n\n"
+               "Capture fsck progress and forward one stream to plymouth\n\n"
+               "  -h --help             Show this help\n"
+               "     --version          Show package version\n",
+               program_invocation_short_name);
+}
+
+static int parse_argv(int argc, char *argv[]) {
+
+        enum {
+                ARG_VERSION = 0x100,
+                ARG_ROOT,
+        };
+
+        static const struct option options[] = {
+                { "help",      no_argument,       NULL, 'h'           },
+                { "version",   no_argument,       NULL, ARG_VERSION   },
+                {}
+        };
+
+        int c;
+
+        assert(argc >= 0);
+        assert(argv);
+
+        while ((c = getopt_long(argc, argv, "hv", options, NULL)) >= 0)
+                switch (c) {
+
+                case 'h':
+                        help();
+                        return 0;
+
+                case ARG_VERSION:
+                        puts(PACKAGE_STRING);
+                        puts(SYSTEMD_FEATURES);
+                        return 0;
+
+                case '?':
+                        return -EINVAL;
+
+                default:
+                        assert_not_reached("Unhandled option");
+                }
+
+        if (optind < argc) {
+                log_error("Extraneous arguments");
+                return -EINVAL;
+        }
+
+        return 1;
+}
+
+int main(int argc, char *argv[]) {
+        _cleanup_manager_free_ Manager *m = NULL;
+        int fd = -1;
+        int r, n;
+
+        log_set_target(LOG_TARGET_AUTO);
+        log_parse_environment();
+        log_open();
+
+        r = parse_argv(argc, argv);
+        if (r <= 0)
+                return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;
+
+        n = sd_listen_fds(0);
+        if (n > 1) {
+                log_error("Too many file descriptors received.");
+                return EXIT_FAILURE;
+        } else if (n == 1) {
+                fd = SD_LISTEN_FDS_START + 0;
+        } else {
+                fd = make_socket_fd(LOG_DEBUG, FSCKD_SOCKET_PATH, SOCK_STREAM | SOCK_CLOEXEC);
+                if (fd < 0) {
+                        log_error_errno(r, "Couldn't create listening socket fd on %s: %m", FSCKD_SOCKET_PATH);
+                        return EXIT_FAILURE;
+                }
+        }
+
+        r = manager_new(&m, fd);
+        if (r < 0) {
+                log_error_errno(r, "Failed to allocate manager: %m");
+                return EXIT_FAILURE;
+        }
+
+        r = sd_event_add_io(m->event, NULL, fd, EPOLLIN, new_connection_handler, m);
+        if (r < 0) {
+                log_error_errno(r, "Can't listen to connection socket: %m");
+                return EXIT_FAILURE;
+        }
+
+        r = run_event_loop_with_timeout(m->event, IDLE_TIME_SECONDS * USEC_PER_SEC);
+        if (r < 0) {
+                log_error_errno(r, "Failed to run event loop: %m");
+                return EXIT_FAILURE;
+        }
+
+        sd_event_get_exit_code(m->event, &r);
+
+        return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;
+}
diff --git a/src/fsckd/fsckd.h b/src/fsckd/fsckd.h
new file mode 100644
index 0000000000..6fe37a7267
--- /dev/null
+++ b/src/fsckd/fsckd.h
@@ -0,0 +1,34 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+/***
+  This file is part of systemd.
+
+  Copyright 2015 Canonical
+
+  Author:
+    Didier Roche <didrocks@ubuntu.com>
+
+  systemd is free software; you can redistribute it and/or modify it
+  under the terms of the GNU Lesser General Public License as published by
+  the Free Software Foundation; either version 2.1 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
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public License
+  along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#define FSCKD_SOCKET_PATH "/run/systemd/fsckd"
+
+#include "libudev.h"
+
+typedef struct FsckProgress {
+        dev_t devnum;
+        size_t cur;
+        size_t max;
+        int pass;
+} FsckProgress;