Make "journalctl -M" work with journals inside overlayfs

Makefile.am

@@ -4399,8 +4399,8 @@ systemd_journal_upload_CFLAGS = \
 	$(LIBCURL_CFLAGS)
 
 systemd_journal_upload_LDADD = \
-	libsystemd-internal.la \
 	libsystemd-journal-internal.la \
+	libsystemd-internal.la \
 	libsystemd-shared.la \
 	$(LIBCURL_LIBS)
 
@@ -4644,6 +4644,8 @@ libsystemd_journal_internal_la_SOURCES = \
 	src/systemd/_sd-common.h \
 	src/journal/journal-file.c \
 	src/journal/journal-file.h \
+	src/journal/journal-dir.c \
+	src/journal/journal-dir.h \
 	src/journal/journal-vacuum.c \
 	src/journal/journal-vacuum.h \
 	src/journal/journal-verify.c \

src/journal-remote/journal-remote-write.c

@@ -59,7 +59,7 @@ static int do_rotate(JournalFile **f, bool compress, bool seal) {
         int r = journal_file_rotate(f, compress, seal);
         if (r < 0) {
                 if (*f)
-                        log_error_errno(r, "Failed to rotate %s: %m", (*f)->path);
+                        log_error_errno(r, "Failed to rotate %s/%s: %m", (*f)->directory->path, (*f)->filename);
                 else
                         log_error_errno(r, "Failed to create rotated journal: %m");
         }
@@ -93,7 +93,7 @@ Writer* writer_free(Writer *w) {
                 return NULL;
 
         if (w->journal) {
-                log_debug("Closing journal file %s.", w->journal->path);
+                log_debug("Closing journal file %s/%s.", w->journal->directory->path, w->journal->filename);
                 journal_file_close(w->journal);
         }
 
@@ -136,8 +136,8 @@ int writer_write(Writer *w,
         assert(iovw->count > 0);
 
         if (journal_file_rotate_suggested(w->journal, 0)) {
-                log_info("%s: Journal header limits reached or header out-of-date, rotating",
-                         w->journal->path);
+                log_info("%s/%s: Journal header limits reached or header out-of-date, rotating",
+                         w->journal->directory->path, w->journal->filename);
                 r = do_rotate(&w->journal, compress, seal);
                 if (r < 0)
                         return r;
@@ -151,12 +151,12 @@ int writer_write(Writer *w,
                 return 1;
         }
 
-        log_debug_errno(r, "%s: Write failed, rotating: %m", w->journal->path);
+        log_debug_errno(r, "%s/%s: Write failed, rotating: %m", w->journal->directory->path, w->journal->filename);
         r = do_rotate(&w->journal, compress, seal);
         if (r < 0)
                 return r;
         else
-                log_debug("%s: Successfully rotated journal", w->journal->path);
+                log_debug("%s/%s: Successfully rotated journal", w->journal->directory->path, w->journal->filename);
 
         log_debug("Retrying write.");
         r = journal_file_append_entry(w->journal, ts, iovw->iovec, iovw->count,

src/journal-remote/journal-remote.c

@@ -162,14 +162,20 @@ static int spawn_getter(const char *getter, const char *url) {
 #define filename_escape(s) xescape((s), "/ ")
 
 static int open_output(Writer *w, const char* host) {
-        _cleanup_free_ char *_output = NULL;
-        const char *output;
+        _cleanup_free_ char *directory = NULL;
+        _cleanup_free_ char *filename = NULL;
+        JournalDirectory *dir;
         int r;
 
         switch (arg_split_mode) {
-        case JOURNAL_WRITE_SPLIT_NONE:
+        case JOURNAL_WRITE_SPLIT_NONE: {
+                const char *output;
+
                 output = arg_output ?: REMOTE_JOURNAL_PATH "/remote.journal";
+                directory = dirname_malloc(output);
+                filename = basename_malloc(output);
                 break;
+        }
 
         case JOURNAL_WRITE_SPLIT_HOST: {
                 _cleanup_free_ char *name;
@@ -180,31 +186,35 @@ static int open_output(Writer *w, const char* host) {
                 if (!name)
                         return log_oom();
 
-                r = asprintf(&_output, "%s/remote-%s.journal",
-                             arg_output ?: REMOTE_JOURNAL_PATH,
-                             name);
+                directory = strdup(arg_output ?: REMOTE_JOURNAL_PATH);
+                r = asprintf(&filename, "remote-%s.journal", name);
                 if (r < 0)
                         return log_oom();
-
-                output = _output;
                 break;
         }
 
         default:
                 assert_not_reached("what?");
         }
 
-        r = journal_file_open_reliably(output,
+        r = journal_directory_open(directory, &dir);
+        if (r < 0) {
+                log_error_errno(r, "Failed to open journal directory %s: %m",
+                                directory);
+                return r;
+        }
+        r = journal_file_open_reliably(dir, filename,
                                        O_RDWR|O_CREAT, 0640,
                                        arg_compress, arg_seal,
                                        &w->metrics,
                                        w->mmap,
                                        NULL, &w->journal);
+        dir = journal_directory_unref(dir);
         if (r < 0)
-                log_error_errno(r, "Failed to open output journal %s: %m",
-                                output);
+                log_error_errno(r, "Failed to open output journal %s/%s: %m",
+                                directory, filename);
         else
-                log_debug("Opened output file %s", w->journal->path);
+                log_debug("Opened output file %s/%s", w->journal->directory->path, w->journal->filename);
         return r;
 }
 

src/journal/journal-dir.c

@@ -0,0 +1,141 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+/***
+  This file is part of systemd.
+
+  Copyright 2015 Endocode AG
+
+  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 "journal-dir.h"
+#include "macro.h"
+#include "util.h"
+
+static int journal_directory_new_steal(char *path, int fd, JournalDirectory **dir) {
+        JournalDirectory *d;
+
+        assert(path);
+        assert(fd >= 0);
+        assert(dir);
+
+        d = new0(JournalDirectory, 1);
+        if (!d)
+                return -ENOMEM;
+        d->path = path;
+        d->fd = fd;
+        d->n_ref = 1;
+        *dir = d;
+        return 0;
+}
+
+int journal_directory_open(const char *path, JournalDirectory **dir)
+{
+        _cleanup_free_ char *p = NULL;
+        _cleanup_close_ int fd = -1;
+        int r;
+
+        assert(path);
+        assert(dir);
+
+        fd = open(path, O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC|O_NOFOLLOW);
+        if (fd < 0)
+                return -errno;
+
+        p = strdup(path);
+        if (!p)
+                return -ENOMEM;
+
+        r = journal_directory_new_steal(p, fd, dir);
+        if (r < 0)
+                return r;
+        p = NULL;
+        fd = -1;
+        return 0;
+}
+
+int journal_directory_new(const char *path, int fd, JournalDirectory **dir)
+{
+        _cleanup_free_ char *p = NULL;
+        _cleanup_close_ int dfd = -1;
+        int r;
+
+        assert(path);
+        assert(fd >= 0);
+        assert(dir);
+
+        dfd = fcntl(fd, F_DUPFD_CLOEXEC, 3);
+        if (dfd < 0)
+                return -errno;
+
+        p = strdup(path);
+        if (!p)
+                return -ENOMEM;
+
+        r = journal_directory_new_steal(p, dfd, dir);
+        if (r < 0)
+                return r;
+        p = NULL;
+        dfd = -1;
+        return 0;
+}
+
+JournalDirectory *journal_directory_ref(JournalDirectory *dir)
+{
+        assert(dir);
+        assert(dir->n_ref > 0);
+
+        dir->n_ref ++;
+        return dir;
+}
+
+JournalDirectory *journal_directory_unref(JournalDirectory *dir)
+{
+        if (dir) {
+                PROTECT_ERRNO;
+
+                assert(dir->n_ref > 0);
+
+                dir->n_ref --;
+                if (!dir->n_ref) {
+                        safe_close(dir->fd);
+                        free(dir->path);
+                        free(dir);
+                }
+        }
+
+        return NULL;
+}
+
+int journal_directory_opendir(JournalDirectory *dir, DIR **de)
+{
+        int fd;
+        DIR* d;
+
+        assert(dir);
+        assert(de);
+
+        fd = fcntl(dir->fd, F_DUPFD_CLOEXEC, 3);
+        if (fd < 0)
+                return -errno;
+
+        d = fdopendir(fd);
+        if (!d) {
+                safe_close(fd);
+                return -errno;
+        }
+
+        *de = d;
+        return 0;
+}

src/journal/journal-dir.h

@@ -0,0 +1,37 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+#pragma once
+
+/***
+  This file is part of systemd.
+
+  Copyright 2015 Endocode AG
+
+  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 <sys/types.h>
+#include <dirent.h>
+
+typedef struct JournalDirectory {
+        char *path;
+        int fd;
+        int n_ref;
+} JournalDirectory;
+
+int journal_directory_open(const char *path, JournalDirectory **dir);
+int journal_directory_new(const char *path, int fd, JournalDirectory **dir);
+JournalDirectory *journal_directory_ref(JournalDirectory *dir);
+JournalDirectory *journal_directory_unref(JournalDirectory *dir);
+int journal_directory_opendir(JournalDirectory *dir, DIR **de);