From e0a3cd2cb02c465c13dcc4e2c092c9e14883ad59 Mon Sep 17 00:00:00 2001

From: Lukas Nykryn <lnykryn@redhat.com>

Date: Wed, 3 Feb 2016 10:37:48 +0100

Subject: [PATCH] Revert "Revert "journald: allow restarting journald without

 losing stream connections""

This reverts commit 91cb89c1b79ef3c475d91319edb0c052cb9f2724.

Resolves: #1359939

---

 src/journal/journald-server.c |  26 ++-

 src/journal/journald-stream.c | 371 +++++++++++++++++++++++++++++-----

 src/journal/journald-stream.h |   3 +-

 3 files changed, 340 insertions(+), 60 deletions(-)

diff --git a/src/journal/journald-server.c b/src/journal/journald-server.c

index 07426b41e8..c1358e1e95 100644

--- a/src/journal/journald-server.c

+++ b/src/journal/journald-server.c

@@ -1477,6 +1477,7 @@ static int server_open_hostname(Server *s) {

 }

 int server_init(Server *s) {

+        _cleanup_fdset_free_ FDSet *fds = NULL;

         int n, r, fd;

         assert(s);

@@ -1573,26 +1574,33 @@ int server_init(Server *s) {

                         s->audit_fd = fd;

                 } else {

-                        log_warning("Unknown socket passed as file descriptor %d, ignoring.", fd);

-                        /* Let's close the fd, better be safe than

-                           sorry. The fd might reference some resource

-                           that we really want to release if we don't

-                           make use of it. */

+                        if (!fds) {

+                                fds = fdset_new();

+                                if (!fds)

+                                        return log_oom();

+                        }

-                        safe_close(fd);

+                        r = fdset_put(fds, fd);

+                        if (r < 0)

+                                return log_oom();

                 }

         }

-        r = server_open_syslog_socket(s);

+        r = server_open_stdout_socket(s, fds);

         if (r < 0)

                 return r;

-        r = server_open_native_socket(s);

+        if (fdset_size(fds) > 0) {

+                log_warning("%u unknown file descriptors passed, closing.", fdset_size(fds));

+                fds = fdset_free(fds);

+        }

+

+        r = server_open_syslog_socket(s);

         if (r < 0)

                 return r;

-        r = server_open_stdout_socket(s);

+        r = server_open_native_socket(s);

         if (r < 0)

                 return r;

diff --git a/src/journal/journald-stream.c b/src/journal/journald-stream.c

index b8607144b3..15c9110c0f 100644

--- a/src/journal/journald-stream.c

+++ b/src/journal/journald-stream.c

@@ -28,8 +28,11 @@

 #endif

 #include "sd-event.h"

+#include "sd-daemon.h"

 #include "socket-util.h"

 #include "selinux-util.h"

+#include "mkdir.h"

+#include "fileio.h"

 #include "journald-server.h"

 #include "journald-stream.h"

 #include "journald-syslog.h"

@@ -66,14 +69,148 @@ struct StdoutStream {

         bool forward_to_kmsg:1;

         bool forward_to_console:1;

+        bool fdstore:1;

+

         char buffer[LINE_MAX+1];

         size_t length;

         sd_event_source *event_source;

+        char *state_file;

+

         LIST_FIELDS(StdoutStream, stdout_stream);

 };

+void stdout_stream_free(StdoutStream *s) {

+        if (!s)

+                return;

+

+        if (s->server) {

+                assert(s->server->n_stdout_streams > 0);

+                s->server->n_stdout_streams --;

+                LIST_REMOVE(stdout_stream, s->server->stdout_streams, s);

+        }

+

+        if (s->event_source) {

+                sd_event_source_set_enabled(s->event_source, SD_EVENT_OFF);

+                s->event_source = sd_event_source_unref(s->event_source);

+        }

+

+        safe_close(s->fd);

+        free(s->label);

+        free(s->identifier);

+        free(s->unit_id);

+        free(s->state_file);

+

+        free(s);

+}

+

+DEFINE_TRIVIAL_CLEANUP_FUNC(StdoutStream*, stdout_stream_free);

+

+static void stdout_stream_destroy(StdoutStream *s) {

+        if (!s)

+                return;

+

+        if (s->state_file)

+                unlink(s->state_file);

+

+        stdout_stream_free(s);

+}

+

+static int stdout_stream_save(StdoutStream *s) {

+        _cleanup_free_ char *temp_path = NULL;

+        _cleanup_fclose_ FILE *f = NULL;

+        int r;

+

+        assert(s);

+

+        if (s->state != STDOUT_STREAM_RUNNING)

+                return 0;

+

+        if (!s->state_file) {

+                struct stat st;

+

+                r = fstat(s->fd, &st);

+                if (r < 0)

+                        return log_warning_errno(errno, "Failed to stat connected stream: %m");

+

+                /* We use device and inode numbers as identifier for the stream */

+                if (asprintf(&s->state_file, "/run/systemd/journal/streams/%lu:%lu", (unsigned long) st.st_dev, (unsigned long) st.st_ino) < 0)

+                        return log_oom();

+        }

+

+        mkdir_p("/run/systemd/journal/streams", 0755);

+

+        r = fopen_temporary(s->state_file, &f, &temp_path);

+        if (r < 0)

+                goto finish;

+

+        fprintf(f,

+                "# This is private data. Do not parse\n"

+                "PRIORITY=%i\n"

+                "LEVEL_PREFIX=%i\n"

+                "FORWARD_TO_SYSLOG=%i\n"

+                "FORWARD_TO_KMSG=%i\n"

+                "FORWARD_TO_CONSOLE=%i\n",

+                s->priority,

+                s->level_prefix,

+                s->forward_to_syslog,

+                s->forward_to_kmsg,

+                s->forward_to_console);

+

+        if (!isempty(s->identifier)) {

+                _cleanup_free_ char *escaped;

+

+                escaped = cescape(s->identifier);

+                if (!escaped) {

+                        r = -ENOMEM;

+                        goto finish;

+                }

+

+                fprintf(f, "IDENTIFIER=%s\n", escaped);

+        }

+

+        if (!isempty(s->unit_id)) {

+                _cleanup_free_ char *escaped;

+

+                escaped = cescape(s->unit_id);

+                if (!escaped) {

+                        r = -ENOMEM;

+                        goto finish;

+                }

+

+                fprintf(f, "UNIT=%s\n", escaped);

+        }

+

+        r = fflush_and_check(f);

+        if (r < 0)

+                goto finish;

+

+        if (rename(temp_path, s->state_file) < 0) {

+                r = -errno;

+                goto finish;

+        }

+

+        free(temp_path);

+        temp_path = NULL;

+

+        /* Store the connection fd in PID 1, so that we get it passed

+         * in again on next start */

+        if (!s->fdstore) {

+                sd_pid_notify_with_fds(0, false, "FDSTORE=1", &s->fd, 1);

+                s->fdstore = true;

+        }

+

+finish:

+        if (temp_path)

+                unlink(temp_path);

+

+        if (r < 0)

+                log_error_errno(r, "Failed to save stream data %s: %m", s->state_file);

+

+        return r;

+}

+

 static int stdout_stream_log(StdoutStream *s, const char *p) {

         struct iovec iovec[N_IOVEC_META_FIELDS + 5];

         int priority;

@@ -219,6 +356,9 @@ static int stdout_stream_line(StdoutStream *s, char *p) {

                 s->forward_to_console = !!r;

                 s->state = STDOUT_STREAM_RUNNING;

+

+                /* Try to save the stream, so that journald can be restarted and we can recover */

+                (void) stdout_stream_save(s);

                 return 0;

         case STDOUT_STREAM_RUNNING:

@@ -313,36 +453,62 @@ static int stdout_stream_process(sd_event_source *es, int fd, uint32_t revents,

         return 1;

 terminate:

-        stdout_stream_free(s);

+        stdout_stream_destroy(s);

         return 0;

 }

-void stdout_stream_free(StdoutStream *s) {

+static int stdout_stream_install(Server *s, int fd, StdoutStream **ret) {

+        _cleanup_(stdout_stream_freep) StdoutStream *stream = NULL;

+        int r;

+

         assert(s);

+        assert(fd >= 0);

-        if (s->server) {

-                assert(s->server->n_stdout_streams > 0);

-                s->server->n_stdout_streams --;

-                LIST_REMOVE(stdout_stream, s->server->stdout_streams, s);

-        }

+        stream = new0(StdoutStream, 1);

+        if (!stream)

+                return log_oom();

-        if (s->event_source) {

-                sd_event_source_set_enabled(s->event_source, SD_EVENT_OFF);

-                s->event_source = sd_event_source_unref(s->event_source);

+        stream->fd = -1;

+        stream->priority = LOG_INFO;

+

+        r = getpeercred(fd, &stream->ucred);

+        if (r < 0)

+                return log_error_errno(r, "Failed to determine peer credentials: %m");

+

+        if (mac_selinux_use()) {

+                r = getpeersec(fd, &stream->label);

+                if (r < 0 && r != -EOPNOTSUPP)

+                        (void) log_warning_errno(r, "Failed to determine peer security context: %m");

         }

-        safe_close(s->fd);

+        (void) shutdown(fd, SHUT_WR);

-        free(s->label);

-        free(s->identifier);

-        free(s->unit_id);

-        free(s);

+        r = sd_event_add_io(s->event, &stream->event_source, fd, EPOLLIN, stdout_stream_process, stream);

+        if (r < 0)

+                return log_error_errno(r, "Failed to add stream to event loop: %m");

+

+        r = sd_event_source_set_priority(stream->event_source, SD_EVENT_PRIORITY_NORMAL+5);

+        if (r < 0)

+                return log_error_errno(r, "Failed to adjust stdout event source priority: %m");

+

+        stream->fd = fd;

+

+        stream->server = s;

+        LIST_PREPEND(stdout_stream, s->stdout_streams, stream);

+        s->n_stdout_streams ++;

+

+        if (ret)

+                *ret = stream;

+

+        stream = NULL;

+

+        return 0;

 }

 static int stdout_stream_new(sd_event_source *es, int listen_fd, uint32_t revents, void *userdata) {

+        _cleanup_close_ int fd = -1;

         Server *s = userdata;

-        StdoutStream *stream;

-        int fd, r;

+        int r;

         assert(s);

@@ -362,61 +528,163 @@ static int stdout_stream_new(sd_event_source *es, int listen_fd, uint32_t revent

         if (s->n_stdout_streams >= STDOUT_STREAMS_MAX) {

                 log_warning("Too many stdout streams, refusing connection.");

-                safe_close(fd);

                 return 0;

         }

-        stream = new0(StdoutStream, 1);

-        if (!stream) {

-                safe_close(fd);

-                return log_oom();

+        r = stdout_stream_install(s, fd, NULL);

+        if (r < 0)

+                return r;

+

+        fd = -1;

+        return 0;

+}

+

+static int stdout_stream_load(StdoutStream *stream, const char *fname) {

+        _cleanup_free_ char

+                *priority = NULL,

+                *level_prefix = NULL,

+                *forward_to_syslog = NULL,

+                *forward_to_kmsg = NULL,

+                *forward_to_console = NULL;

+        int r;

+

+        assert(stream);

+        assert(fname);

+

+        if (!stream->state_file) {

+                stream->state_file = strappend("/run/systemd/journal/streams/", fname);

+                if (!stream->state_file)

+                        return log_oom();

         }

-        stream->fd = fd;

+        r = parse_env_file(stream->state_file, NEWLINE,

+                           "PRIORITY", &priority,

+                           "LEVEL_PREFIX", &level_prefix,

+                           "FORWARD_TO_SYSLOG", &forward_to_syslog,

+                           "FORWARD_TO_KMSG", &forward_to_kmsg,

+                           "FORWARD_TO_CONSOLE", &forward_to_console,

+                           "IDENTIFIER", &stream->identifier,

+                           "UNIT", &stream->unit_id,

+                           NULL);

+        if (r < 0)

+                return log_error_errno(r, "Failed to read: %s", stream->state_file);

-        r = getpeercred(fd, &stream->ucred);

-        if (r < 0) {

-                log_error_errno(errno, "Failed to determine peer credentials: %m");

-                goto fail;

+        if (priority) {

+                int p;

+

+                p = log_level_from_string(priority);

+                if (p >= 0)

+                        stream->priority = p;

         }

-#ifdef HAVE_SELINUX

-        if (mac_selinux_use()) {

-                r = getpeersec(fd, &stream->label);

-                if (r < 0 && r != -EOPNOTSUPP)

-                        (void) log_warning_errno(r, "Failed to determine peer security context: %m");

+        if (level_prefix) {

+                r = parse_boolean(level_prefix);

+                if (r >= 0)

+                        stream->level_prefix = r;

         }

-#endif

-        if (shutdown(fd, SHUT_WR) < 0) {

-                log_error_errno(errno, "Failed to shutdown writing side of socket: %m");

-                goto fail;

+        if (forward_to_syslog) {

+                r = parse_boolean(forward_to_syslog);

+                if (r >= 0)

+                        stream->forward_to_syslog = r;

         }

-        r = sd_event_add_io(s->event, &stream->event_source, fd, EPOLLIN, stdout_stream_process, stream);

-        if (r < 0) {

-                log_error_errno(r, "Failed to add stream to event loop: %m");

-                goto fail;

+        if (forward_to_kmsg) {

+                r = parse_boolean(forward_to_kmsg);

+                if (r >= 0)

+                        stream->forward_to_kmsg = r;

         }

-        r = sd_event_source_set_priority(stream->event_source, SD_EVENT_PRIORITY_NORMAL+5);

-        if (r < 0) {

-                log_error_errno(r, "Failed to adjust stdout event source priority: %m");

-                goto fail;

+        if (forward_to_console) {

+                r = parse_boolean(forward_to_console);

+                if (r >= 0)

+                        stream->forward_to_console = r;

         }

-        stream->server = s;

-        LIST_PREPEND(stdout_stream, s->stdout_streams, stream);

-        s->n_stdout_streams ++;

+        return 0;

+}

+

+static int stdout_stream_restore(Server *s, const char *fname, int fd) {

+        StdoutStream *stream;

+        int r;

+

+        assert(s);

+        assert(fname);

+        assert(fd >= 0);

+

+        if (s->n_stdout_streams >= STDOUT_STREAMS_MAX) {

+                log_warning("Too many stdout streams, refusing restoring of stream.");

+                return -ENOBUFS;

+        }

+

+        r = stdout_stream_install(s, fd, &stream);

+        if (r < 0)

+                return r;

+

+        stream->state = STDOUT_STREAM_RUNNING;

+        stream->fdstore = true;

+

+        /* Ignore all parsing errors */

+        (void) stdout_stream_load(stream, fname);

         return 0;

+}

+

+static int server_restore_streams(Server *s, FDSet *fds) {

+        _cleanup_closedir_ DIR *d = NULL;

+        struct dirent *de;

+        int r;

+

+        d = opendir("/run/systemd/journal/streams");

+        if (!d) {

+                if (errno == ENOENT)

+                        return 0;

+

+                return log_warning_errno(errno, "Failed to enumerate /run/systemd/journal/streams: %m");

+        }

+

+        FOREACH_DIRENT(de, d, goto fail) {

+                unsigned long st_dev, st_ino;

+                bool found = false;

+                Iterator i;

+                int fd;

+

+                if (sscanf(de->d_name, "%lu:%lu", &st_dev, &st_ino) != 2)

+                        continue;

+

+                FDSET_FOREACH(fd, fds, i) {

+                        struct stat st;

+

+                        if (fstat(fd, &st) < 0)

+                                return log_error_errno(errno, "Failed to stat %s: %m", de->d_name);

+

+                        if (S_ISSOCK(st.st_mode) && st.st_dev == st_dev && st.st_ino == st_ino) {

+                                found = true;

+                                break;

+                        }

+                }

+

+                if (!found) {

+                        /* No file descriptor? Then let's delete the state file */

+                        log_debug("Cannot restore stream file %s", de->d_name);

+                        unlinkat(dirfd(d), de->d_name, 0);

+                        continue;

+                }

+

+                fdset_remove(fds, fd);

+

+                r = stdout_stream_restore(s, de->d_name, fd);

+                if (r < 0)

+                        safe_close(fd);

+        }

-fail:

-        stdout_stream_free(stream);

         return 0;

+

+fail:

+        return log_error_errno(errno, "Failed to read streams directory: %m");

 }

-int server_open_stdout_socket(Server *s) {

+int server_open_stdout_socket(Server *s, FDSet *fds) {

         int r;

         assert(s);

@@ -452,5 +720,8 @@ int server_open_stdout_socket(Server *s) {

         if (r < 0)

                 return log_error_errno(r, "Failed to adjust priority of stdout server event source: %m");

+        /* Try to restore streams, but don't bother if this fails */

+        (void) server_restore_streams(s, fds);

+

         return 0;

 }

diff --git a/src/journal/journald-stream.h b/src/journal/journald-stream.h

index 8cad012967..94bf955d78 100644

--- a/src/journal/journald-stream.h

+++ b/src/journal/journald-stream.h

@@ -21,8 +21,9 @@

   along with systemd; If not, see <http://www.gnu.org/licenses/>.

 ***/

+#include "fdset.h"

 #include "journald-server.h"

-int server_open_stdout_socket(Server *s);

+int server_open_stdout_socket(Server *s, FDSet *fds);

 void stdout_stream_free(StdoutStream *s);