Adding upstream version 2.1.6.upstream/2.1.6

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

1 files changed, 919 insertions, 0 deletions

diff --git a/lib/cib/cib_file.c b/lib/cib/cib_file.c
new file mode 100644
index 0000000..7d05965
--- /dev/null
+++ b/lib/cib/cib_file.c
@@ -0,0 +1,919 @@
+/*
+ * Original copyright 2004 International Business Machines
+ * Later changes copyright 2008-2023 the Pacemaker project contributors
+ *
+ * The version control history for this file may have further details.
+ *
+ * This source code is licensed under the GNU Lesser General Public License
+ * version 2.1 or later (LGPLv2.1+) WITHOUT ANY WARRANTY.
+ */
+
+#include <crm_internal.h>
+#include <unistd.h>
+#include <limits.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdarg.h>
+#include <string.h>
+#include <pwd.h>
+
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <glib.h>
+
+#include <crm/crm.h>
+#include <crm/cib/internal.h>
+#include <crm/msg_xml.h>
+#include <crm/common/ipc.h>
+#include <crm/common/xml.h>
+#include <crm/common/xml_internal.h>
+
+#define CIB_SERIES "cib"
+#define CIB_SERIES_MAX 100
+#define CIB_SERIES_BZIP FALSE /* Must be false because archived copies are
+                                 created with hard links
+                               */
+
+#define CIB_LIVE_NAME CIB_SERIES ".xml"
+
+enum cib_file_flags {
+    cib_file_flag_dirty = (1 << 0),
+    cib_file_flag_live  = (1 << 1),
+};
+
+typedef struct cib_file_opaque_s {
+    uint32_t flags; // Group of enum cib_file_flags
+    char *filename;
+} cib_file_opaque_t;
+
+struct cib_func_entry {
+    const char *op;
+    gboolean read_only;
+    cib_op_t fn;
+};
+
+static struct cib_func_entry cib_file_ops[] = {
+    { PCMK__CIB_REQUEST_QUERY,       TRUE,   cib_process_query },
+    { PCMK__CIB_REQUEST_MODIFY,      FALSE,  cib_process_modify },
+    { PCMK__CIB_REQUEST_APPLY_PATCH, FALSE,  cib_process_diff },
+    { PCMK__CIB_REQUEST_BUMP,        FALSE,  cib_process_bump },
+    { PCMK__CIB_REQUEST_REPLACE,     FALSE,  cib_process_replace },
+    { PCMK__CIB_REQUEST_CREATE,      FALSE,  cib_process_create },
+    { PCMK__CIB_REQUEST_DELETE,      FALSE,  cib_process_delete },
+    { PCMK__CIB_REQUEST_ERASE,       FALSE,  cib_process_erase },
+    { PCMK__CIB_REQUEST_UPGRADE,     FALSE,  cib_process_upgrade },
+};
+
+static xmlNode *in_mem_cib = NULL;
+
+/* cib_file_backup() and cib_file_write_with_digest() need to chown the
+ * written files only in limited circumstances, so these variables allow
+ * that to be indicated without affecting external callers
+ */
+static uid_t cib_file_owner = 0;
+static uid_t cib_file_group = 0;
+static gboolean cib_do_chown = FALSE;
+
+#define cib_set_file_flags(cibfile, flags_to_set) do {                  \
+        (cibfile)->flags = pcmk__set_flags_as(__func__, __LINE__,       \
+                                              LOG_TRACE, "CIB file",    \
+                                              cibfile->filename,        \
+                                              (cibfile)->flags,         \
+                                              (flags_to_set),           \
+                                              #flags_to_set);           \
+    } while (0)
+
+#define cib_clear_file_flags(cibfile, flags_to_clear) do {              \
+        (cibfile)->flags = pcmk__clear_flags_as(__func__, __LINE__,     \
+                                                LOG_TRACE, "CIB file",  \
+                                                cibfile->filename,      \
+                                                (cibfile)->flags,       \
+                                                (flags_to_clear),       \
+                                                #flags_to_clear);       \
+    } while (0)
+
+/*!
+ * \internal
+ * \brief Check whether a file is the live CIB
+ *
+ * \param[in] filename Name of file to check
+ *
+ * \return TRUE if file exists and its real path is same as live CIB's
+ */
+static gboolean
+cib_file_is_live(const char *filename)
+{
+    gboolean same = FALSE;
+
+    if (filename != NULL) {
+        // Canonicalize file names for true comparison
+        char *real_filename = NULL;
+
+        if (pcmk__real_path(filename, &real_filename) == pcmk_rc_ok) {
+            char *real_livename = NULL;
+
+            if (pcmk__real_path(CRM_CONFIG_DIR "/" CIB_LIVE_NAME,
+                                &real_livename) == pcmk_rc_ok) {
+                same = !strcmp(real_filename, real_livename);
+                free(real_livename);
+            }
+            free(real_filename);
+        }
+    }
+    return same;
+}
+
+static int
+cib_file_perform_op_delegate(cib_t *cib, const char *op, const char *host,
+                             const char *section, xmlNode *data,
+                             xmlNode **output_data, int call_options,
+                             const char *user_name)
+{
+    int rc = pcmk_ok;
+    char *effective_user = NULL;
+    gboolean query = FALSE;
+    gboolean changed = FALSE;
+    xmlNode *request = NULL;
+    xmlNode *output = NULL;
+    xmlNode *cib_diff = NULL;
+    xmlNode *result_cib = NULL;
+    cib_op_t *fn = NULL;
+    int lpc = 0;
+    static int max_msg_types = PCMK__NELEM(cib_file_ops);
+    cib_file_opaque_t *private = cib->variant_opaque;
+
+    crm_info("Handling %s operation for %s as %s",
+             (op? op : "invalid"), (section? section : "entire CIB"),
+             (user_name? user_name : "default user"));
+
+    cib__set_call_options(call_options, "file operation",
+                          cib_no_mtime|cib_inhibit_bcast|cib_scope_local);
+
+    if (cib->state == cib_disconnected) {
+        return -ENOTCONN;
+    }
+
+    if (output_data != NULL) {
+        *output_data = NULL;
+    }
+
+    if (op == NULL) {
+        return -EINVAL;
+    }
+
+    for (lpc = 0; lpc < max_msg_types; lpc++) {
+        if (pcmk__str_eq(op, cib_file_ops[lpc].op, pcmk__str_casei)) {
+            fn = &(cib_file_ops[lpc].fn);
+            query = cib_file_ops[lpc].read_only;
+            break;
+        }
+    }
+
+    if (fn == NULL) {
+        return -EPROTONOSUPPORT;
+    }
+
+    cib->call_id++;
+    request = cib_create_op(cib->call_id, op, host, section, data, call_options,
+                            user_name);
+    if(user_name) {
+        crm_xml_add(request, XML_ACL_TAG_USER, user_name);
+    }
+
+    /* Mirror the logic in cib_prepare_common() */
+    if (section != NULL && data != NULL && pcmk__str_eq(crm_element_name(data), XML_TAG_CIB, pcmk__str_none)) {
+        data = pcmk_find_cib_element(data, section);
+    }
+
+    rc = cib_perform_op(op, call_options, fn, query,
+                        section, request, data, TRUE, &changed, in_mem_cib, &result_cib, &cib_diff,
+                        &output);
+
+    free_xml(request);
+    if (rc == -pcmk_err_schema_validation) {
+        validate_xml_verbose(result_cib);
+    }
+
+    if (rc != pcmk_ok) {
+        free_xml(result_cib);
+
+    } else if (query == FALSE) {
+        pcmk__output_t *out = NULL;
+
+        rc = pcmk_rc2legacy(pcmk__log_output_new(&out));
+        CRM_CHECK(rc == pcmk_ok, goto done);
+
+        pcmk__output_set_log_level(out, LOG_DEBUG);
+        rc = out->message(out, "xml-patchset", cib_diff);
+        out->finish(out, pcmk_rc2exitc(rc), true, NULL);
+        pcmk__output_free(out);
+        rc = pcmk_ok;
+
+        free_xml(in_mem_cib);
+        in_mem_cib = result_cib;
+        cib_set_file_flags(private, cib_file_flag_dirty);
+    }
+
+    if (cib->op_callback != NULL) {
+        cib->op_callback(NULL, cib->call_id, rc, output);
+    }
+
+    if ((output_data != NULL) && (output != NULL)) {
+        *output_data = (output == in_mem_cib)? copy_xml(output) : output;
+    }
+
+done:
+    free_xml(cib_diff);
+
+    if ((output_data == NULL) && (output != in_mem_cib)) {
+        /* Don't free output if we're still using it. (output_data != NULL)
+         * means we may have assigned *output_data = output above.
+         */
+        free_xml(output);
+    }
+    free(effective_user);
+    return rc;
+}
+
+/*!
+ * \internal
+ * \brief Read CIB from disk and validate it against XML schema
+ *
+ * \param[in] filename Name of file to read CIB from
+ *
+ * \return pcmk_ok on success,
+ *         -ENXIO if file does not exist (or stat() otherwise fails), or
+ *         -pcmk_err_schema_validation if XML doesn't parse or validate
+ * \note If filename is the live CIB, this will *not* verify its digest,
+ *       though that functionality would be trivial to add here.
+ *       Also, this will *not* verify that the file is writable,
+ *       because some callers might not need to write.
+ */
+static int
+load_file_cib(const char *filename)
+{
+    struct stat buf;
+    xmlNode *root = NULL;
+
+    /* Ensure file is readable */
+    if (strcmp(filename, "-") && (stat(filename, &buf) < 0)) {
+        return -ENXIO;
+    }
+
+    /* Parse XML from file */
+    root = filename2xml(filename);
+    if (root == NULL) {
+        return -pcmk_err_schema_validation;
+    }
+
+    /* Add a status section if not already present */
+    if (find_xml_node(root, XML_CIB_TAG_STATUS, FALSE) == NULL) {
+        create_xml_node(root, XML_CIB_TAG_STATUS);
+    }
+
+    /* Validate XML against its specified schema */
+    if (validate_xml(root, NULL, TRUE) == FALSE) {
+        const char *schema = crm_element_value(root, XML_ATTR_VALIDATION);
+
+        crm_err("CIB does not validate against %s", schema);
+        free_xml(root);
+        return -pcmk_err_schema_validation;
+    }
+
+    /* Remember the parsed XML for later use */
+    in_mem_cib = root;
+    return pcmk_ok;
+}
+
+static int
+cib_file_signon(cib_t *cib, const char *name, enum cib_conn_type type)
+{
+    int rc = pcmk_ok;
+    cib_file_opaque_t *private = cib->variant_opaque;
+
+    if (private->filename == NULL) {
+        rc = -EINVAL;
+    } else {
+        rc = load_file_cib(private->filename);
+    }
+
+    if (rc == pcmk_ok) {
+        crm_debug("Opened connection to local file '%s' for %s",
+                  private->filename, name);
+        cib->state = cib_connected_command;
+        cib->type = cib_command;
+
+    } else {
+        crm_info("Connection to local file '%s' for %s failed: %s\n",
+                 private->filename, name, pcmk_strerror(rc));
+    }
+    return rc;
+}
+
+/*!
+ * \internal
+ * \brief Write out the in-memory CIB to a live CIB file
+ *
+ * param[in,out] path  Full path to file to write
+ *
+ * \return 0 on success, -1 on failure
+ */
+static int
+cib_file_write_live(char *path)
+{
+    uid_t uid = geteuid();
+    struct passwd *daemon_pwent;
+    char *sep = strrchr(path, '/');
+    const char *cib_dirname, *cib_filename;
+    int rc = 0;
+
+    /* Get the desired uid/gid */
+    errno = 0;
+    daemon_pwent = getpwnam(CRM_DAEMON_USER);
+    if (daemon_pwent == NULL) {
+        crm_perror(LOG_ERR, "Could not find %s user", CRM_DAEMON_USER);
+        return -1;
+    }
+
+    /* If we're root, we can change the ownership;
+     * if we're daemon, anything we create will be OK;
+     * otherwise, block access so we don't create wrong owner
+     */
+    if ((uid != 0) && (uid != daemon_pwent->pw_uid)) {
+        crm_perror(LOG_ERR, "Must be root or %s to modify live CIB",
+                   CRM_DAEMON_USER);
+        return 0;
+    }
+
+    /* fancy footwork to separate dirname from filename
+     * (we know the canonical name maps to the live CIB,
+     * but the given name might be relative, or symlinked)
+     */
+    if (sep == NULL) { /* no directory component specified */
+        cib_dirname = "./";
+        cib_filename = path;
+    } else if (sep == path) { /* given name is in / */
+        cib_dirname = "/";
+        cib_filename = path + 1;
+    } else { /* typical case; split given name into parts */
+        *sep = '\0';
+        cib_dirname = path;
+        cib_filename = sep + 1;
+    }
+
+    /* if we're root, we want to update the file ownership */
+    if (uid == 0) {
+        cib_file_owner = daemon_pwent->pw_uid;
+        cib_file_group = daemon_pwent->pw_gid;
+        cib_do_chown = TRUE;
+    }
+
+    /* write the file */
+    if (cib_file_write_with_digest(in_mem_cib, cib_dirname,
+                                   cib_filename) != pcmk_ok) {
+        rc = -1;
+    }
+
+    /* turn off file ownership changes, for other callers */
+    if (uid == 0) {
+        cib_do_chown = FALSE;
+    }
+
+    /* undo fancy stuff */
+    if ((sep != NULL) && (*sep == '\0')) {
+        *sep = '/';
+    }
+
+    return rc;
+}
+
+/*!
+ * \internal
+ * \brief Sign-off method for CIB file variants
+ *
+ * This will write the file to disk if needed, and free the in-memory CIB. If
+ * the file is the live CIB, it will compute and write a signature as well.
+ *
+ * \param[in,out] cib  CIB object to sign off
+ *
+ * \return pcmk_ok on success, pcmk_err_generic on failure
+ * \todo This method should refuse to write the live CIB if the CIB manager is
+ *       running.
+ */
+static int
+cib_file_signoff(cib_t *cib)
+{
+    int rc = pcmk_ok;
+    cib_file_opaque_t *private = cib->variant_opaque;
+
+    crm_debug("Disconnecting from the CIB manager");
+    cib->state = cib_disconnected;
+    cib->type = cib_no_connection;
+
+    /* If the in-memory CIB has been changed, write it to disk */
+    if (pcmk_is_set(private->flags, cib_file_flag_dirty)) {
+
+        /* If this is the live CIB, write it out with a digest */
+        if (pcmk_is_set(private->flags, cib_file_flag_live)) {
+            if (cib_file_write_live(private->filename) < 0) {
+                rc = pcmk_err_generic;
+            }
+
+        /* Otherwise, it's a simple write */
+        } else {
+            gboolean do_bzip = pcmk__ends_with_ext(private->filename, ".bz2");
+
+            if (write_xml_file(in_mem_cib, private->filename, do_bzip) <= 0) {
+                rc = pcmk_err_generic;
+            }
+        }
+
+        if (rc == pcmk_ok) {
+            crm_info("Wrote CIB to %s", private->filename);
+            cib_clear_file_flags(private, cib_file_flag_dirty);
+        } else {
+            crm_err("Could not write CIB to %s", private->filename);
+        }
+    }
+
+    /* Free the in-memory CIB */
+    free_xml(in_mem_cib);
+    in_mem_cib = NULL;
+    return rc;
+}
+
+static int
+cib_file_free(cib_t *cib)
+{
+    int rc = pcmk_ok;
+
+    if (cib->state != cib_disconnected) {
+        rc = cib_file_signoff(cib);
+    }
+
+    if (rc == pcmk_ok) {
+        cib_file_opaque_t *private = cib->variant_opaque;
+
+        free(private->filename);
+        free(cib->cmds);
+        free(private);
+        free(cib);
+
+    } else {
+        fprintf(stderr, "Couldn't sign off: %d\n", rc);
+    }
+
+    return rc;
+}
+
+static int
+cib_file_inputfd(cib_t *cib)
+{
+    return -EPROTONOSUPPORT;
+}
+
+static int
+cib_file_register_notification(cib_t *cib, const char *callback, int enabled)
+{
+    return -EPROTONOSUPPORT;
+}
+
+static int
+cib_file_set_connection_dnotify(cib_t *cib,
+                                void (*dnotify) (gpointer user_data))
+{
+    return -EPROTONOSUPPORT;
+}
+
+/*!
+ * \internal
+ * \brief Get the given CIB connection's unique client identifier
+ *
+ * \param[in]  cib       CIB connection
+ * \param[out] async_id  If not \p NULL, where to store asynchronous client ID
+ * \param[out] sync_id   If not \p NULL, where to store synchronous client ID
+ *
+ * \return Legacy Pacemaker return code (specifically, \p -EPROTONOSUPPORT)
+ *
+ * \note This is the \p cib_file variant implementation of
+ *       \p cib_api_operations_t:client_id().
+ * \note A \p cib_file object doesn't connect to the CIB and is never assigned a
+ *       client ID.
+ */
+static int
+cib_file_client_id(const cib_t *cib, const char **async_id,
+                   const char **sync_id)
+{
+    if (async_id != NULL) {
+        *async_id = NULL;
+    }
+    if (sync_id != NULL) {
+        *sync_id = NULL;
+    }
+    return -EPROTONOSUPPORT;
+}
+
+cib_t *
+cib_file_new(const char *cib_location)
+{
+    cib_file_opaque_t *private = NULL;
+    cib_t *cib = cib_new_variant();
+
+    if (cib == NULL) {
+        return NULL;
+    }
+
+    private = calloc(1, sizeof(cib_file_opaque_t));
+
+    if (private == NULL) {
+        free(cib);
+        return NULL;
+    }
+
+    cib->variant = cib_file;
+    cib->variant_opaque = private;
+
+    if (cib_location == NULL) {
+        cib_location = getenv("CIB_file");
+        CRM_CHECK(cib_location != NULL, return NULL); // Shouldn't be possible
+    }
+    private->flags = 0;
+    if (cib_file_is_live(cib_location)) {
+        cib_set_file_flags(private, cib_file_flag_live);
+        crm_trace("File %s detected as live CIB", cib_location);
+    }
+    private->filename = strdup(cib_location);
+
+    /* assign variant specific ops */
+    cib->delegate_fn = cib_file_perform_op_delegate;
+    cib->cmds->signon = cib_file_signon;
+    cib->cmds->signoff = cib_file_signoff;
+    cib->cmds->free = cib_file_free;
+    cib->cmds->inputfd = cib_file_inputfd;
+
+    cib->cmds->register_notification = cib_file_register_notification;
+    cib->cmds->set_connection_dnotify = cib_file_set_connection_dnotify;
+
+    cib->cmds->client_id = cib_file_client_id;
+
+    return cib;
+}
+
+/*!
+ * \internal
+ * \brief Compare the calculated digest of an XML tree against a signature file
+ *
+ * \param[in] root     Root of XML tree to compare
+ * \param[in] sigfile  Name of signature file containing digest to compare
+ *
+ * \return TRUE if digests match or signature file does not exist, else FALSE
+ */
+static gboolean
+cib_file_verify_digest(xmlNode *root, const char *sigfile)
+{
+    gboolean passed = FALSE;
+    char *expected;
+    int rc = pcmk__file_contents(sigfile, &expected);
+
+    switch (rc) {
+        case pcmk_rc_ok:
+            if (expected == NULL) {
+                crm_err("On-disk digest at %s is empty", sigfile);
+                return FALSE;
+            }
+            break;
+        case ENOENT:
+            crm_warn("No on-disk digest present at %s", sigfile);
+            return TRUE;
+        default:
+            crm_err("Could not read on-disk digest from %s: %s",
+                    sigfile, pcmk_rc_str(rc));
+            return FALSE;
+    }
+    passed = pcmk__verify_digest(root, expected);
+    free(expected);
+    return passed;
+}
+
+/*!
+ * \internal
+ * \brief Read an XML tree from a file and verify its digest
+ *
+ * \param[in]  filename  Name of XML file to read
+ * \param[in]  sigfile   Name of signature file containing digest to compare
+ * \param[out] root      If non-NULL, will be set to pointer to parsed XML tree
+ *
+ * \return 0 if file was successfully read, parsed and verified, otherwise:
+ *         -errno on stat() failure,
+ *         -pcmk_err_cib_corrupt if file size is 0 or XML is not parseable, or
+ *         -pcmk_err_cib_modified if digests do not match
+ * \note If root is non-NULL, it is the caller's responsibility to free *root on
+ *       successful return.
+ */
+int
+cib_file_read_and_verify(const char *filename, const char *sigfile, xmlNode **root)
+{
+    int s_res;
+    struct stat buf;
+    char *local_sigfile = NULL;
+    xmlNode *local_root = NULL;
+
+    CRM_ASSERT(filename != NULL);
+    if (root) {
+        *root = NULL;
+    }
+
+    /* Verify that file exists and its size is nonzero */
+    s_res = stat(filename, &buf);
+    if (s_res < 0) {
+        crm_perror(LOG_WARNING, "Could not verify cluster configuration file %s", filename);
+        return -errno;
+    } else if (buf.st_size == 0) {
+        crm_warn("Cluster configuration file %s is corrupt (size is zero)", filename);
+        return -pcmk_err_cib_corrupt;
+    }
+
+    /* Parse XML */
+    local_root = filename2xml(filename);
+    if (local_root == NULL) {
+        crm_warn("Cluster configuration file %s is corrupt (unparseable as XML)", filename);
+        return -pcmk_err_cib_corrupt;
+    }
+
+    /* If sigfile is not specified, use original file name plus .sig */
+    if (sigfile == NULL) {
+        sigfile = local_sigfile = crm_strdup_printf("%s.sig", filename);
+    }
+
+    /* Verify that digests match */
+    if (cib_file_verify_digest(local_root, sigfile) == FALSE) {
+        free(local_sigfile);
+        free_xml(local_root);
+        return -pcmk_err_cib_modified;
+    }
+
+    free(local_sigfile);
+    if (root) {
+        *root = local_root;
+    } else {
+        free_xml(local_root);
+    }
+    return pcmk_ok;
+}
+
+/*!
+ * \internal
+ * \brief Back up a CIB
+ *
+ * \param[in] cib_dirname Directory containing CIB file and backups
+ * \param[in] cib_filename Name (relative to cib_dirname) of CIB file to back up
+ *
+ * \return 0 on success, -1 on error
+ */
+static int
+cib_file_backup(const char *cib_dirname, const char *cib_filename)
+{
+    int rc = 0;
+    unsigned int seq;
+    char *cib_path = crm_strdup_printf("%s/%s", cib_dirname, cib_filename);
+    char *cib_digest = crm_strdup_printf("%s.sig", cib_path);
+    char *backup_path;
+    char *backup_digest;
+
+    // Determine backup and digest file names
+    if (pcmk__read_series_sequence(cib_dirname, CIB_SERIES,
+                                   &seq) != pcmk_rc_ok) {
+        // @TODO maybe handle errors better ...
+        seq = 0;
+    }
+    backup_path = pcmk__series_filename(cib_dirname, CIB_SERIES, seq,
+                                        CIB_SERIES_BZIP);
+    backup_digest = crm_strdup_printf("%s.sig", backup_path);
+
+    /* Remove the old backups if they exist */
+    unlink(backup_path);
+    unlink(backup_digest);
+
+    /* Back up the CIB, by hard-linking it to the backup name */
+    if ((link(cib_path, backup_path) < 0) && (errno != ENOENT)) {
+        crm_perror(LOG_ERR, "Could not archive %s by linking to %s",
+                   cib_path, backup_path);
+        rc = -1;
+
+    /* Back up the CIB signature similarly */
+    } else if ((link(cib_digest, backup_digest) < 0) && (errno != ENOENT)) {
+        crm_perror(LOG_ERR, "Could not archive %s by linking to %s",
+                   cib_digest, backup_digest);
+        rc = -1;
+
+    /* Update the last counter and ensure everything is sync'd to media */
+    } else {
+        pcmk__write_series_sequence(cib_dirname, CIB_SERIES, ++seq,
+                                    CIB_SERIES_MAX);
+        if (cib_do_chown) {
+            int rc2;
+
+            if ((chown(backup_path, cib_file_owner, cib_file_group) < 0)
+                    && (errno != ENOENT)) {
+                crm_perror(LOG_ERR, "Could not set owner of %s", backup_path);
+                rc = -1;
+            }
+            if ((chown(backup_digest, cib_file_owner, cib_file_group) < 0)
+                    && (errno != ENOENT)) {
+                crm_perror(LOG_ERR, "Could not set owner of %s", backup_digest);
+                rc = -1;
+            }
+            rc2 = pcmk__chown_series_sequence(cib_dirname, CIB_SERIES,
+                                              cib_file_owner, cib_file_group);
+            if (rc2 != pcmk_rc_ok) {
+                crm_err("Could not set owner of sequence file in %s: %s",
+                        cib_dirname, pcmk_rc_str(rc2));
+                rc = -1;
+            }
+        }
+        pcmk__sync_directory(cib_dirname);
+        crm_info("Archived previous version as %s", backup_path);
+    }
+
+    free(cib_path);
+    free(cib_digest);
+    free(backup_path);
+    free(backup_digest);
+    return rc;
+}
+
+/*!
+ * \internal
+ * \brief Prepare CIB XML to be written to disk
+ *
+ * Set num_updates to 0, set cib-last-written to the current timestamp,
+ * and strip out the status section.
+ *
+ * \param[in,out] root  Root of CIB XML tree
+ *
+ * \return void
+ */
+static void
+cib_file_prepare_xml(xmlNode *root)
+{
+    xmlNode *cib_status_root = NULL;
+
+    /* Always write out with num_updates=0 and current last-written timestamp */
+    crm_xml_add(root, XML_ATTR_NUMUPDATES, "0");
+    pcmk__xe_add_last_written(root);
+
+    /* Delete status section before writing to file, because
+     * we discard it on startup anyway, and users get confused by it */
+    cib_status_root = find_xml_node(root, XML_CIB_TAG_STATUS, TRUE);
+    CRM_LOG_ASSERT(cib_status_root != NULL);
+    if (cib_status_root != NULL) {
+        free_xml(cib_status_root);
+    }
+}
+
+/*!
+ * \internal
+ * \brief Write CIB to disk, along with a signature file containing its digest
+ *
+ * \param[in,out] cib_root      Root of XML tree to write
+ * \param[in]     cib_dirname   Directory containing CIB and signature files
+ * \param[in]     cib_filename  Name (relative to cib_dirname) of file to write
+ *
+ * \return pcmk_ok on success,
+ *         pcmk_err_cib_modified if existing cib_filename doesn't match digest,
+ *         pcmk_err_cib_backup if existing cib_filename couldn't be backed up,
+ *         or pcmk_err_cib_save if new cib_filename couldn't be saved
+ */
+int
+cib_file_write_with_digest(xmlNode *cib_root, const char *cib_dirname,
+                           const char *cib_filename)
+{
+    int exit_rc = pcmk_ok;
+    int rc, fd;
+    char *digest = NULL;
+
+    /* Detect CIB version for diagnostic purposes */
+    const char *epoch = crm_element_value(cib_root, XML_ATTR_GENERATION);
+    const char *admin_epoch = crm_element_value(cib_root,
+                                                XML_ATTR_GENERATION_ADMIN);
+
+    /* Determine full CIB and signature pathnames */
+    char *cib_path = crm_strdup_printf("%s/%s", cib_dirname, cib_filename);
+    char *digest_path = crm_strdup_printf("%s.sig", cib_path);
+
+    /* Create temporary file name patterns for writing out CIB and signature */
+    char *tmp_cib = crm_strdup_printf("%s/cib.XXXXXX", cib_dirname);
+    char *tmp_digest = crm_strdup_printf("%s/cib.XXXXXX", cib_dirname);
+
+    CRM_ASSERT((cib_path != NULL) && (digest_path != NULL)
+               && (tmp_cib != NULL) && (tmp_digest != NULL));
+
+    /* Ensure the admin didn't modify the existing CIB underneath us */
+    crm_trace("Reading cluster configuration file %s", cib_path);
+    rc = cib_file_read_and_verify(cib_path, NULL, NULL);
+    if ((rc != pcmk_ok) && (rc != -ENOENT)) {
+        crm_err("%s was manually modified while the cluster was active!",
+                cib_path);
+        exit_rc = pcmk_err_cib_modified;
+        goto cleanup;
+    }
+
+    /* Back up the existing CIB */
+    if (cib_file_backup(cib_dirname, cib_filename) < 0) {
+        exit_rc = pcmk_err_cib_backup;
+        goto cleanup;
+    }
+
+    crm_debug("Writing CIB to disk");
+    umask(S_IWGRP | S_IWOTH | S_IROTH);
+    cib_file_prepare_xml(cib_root);
+
+    /* Write the CIB to a temporary file, so we can deploy (near) atomically */
+    fd = mkstemp(tmp_cib);
+    if (fd < 0) {
+        crm_perror(LOG_ERR, "Couldn't open temporary file %s for writing CIB",
+                   tmp_cib);
+        exit_rc = pcmk_err_cib_save;
+        goto cleanup;
+    }
+
+    /* Protect the temporary file */
+    if (fchmod(fd, S_IRUSR | S_IWUSR) < 0) {
+        crm_perror(LOG_ERR, "Couldn't protect temporary file %s for writing CIB",
+                   tmp_cib);
+        exit_rc = pcmk_err_cib_save;
+        goto cleanup;
+    }
+    if (cib_do_chown && (fchown(fd, cib_file_owner, cib_file_group) < 0)) {
+        crm_perror(LOG_ERR, "Couldn't protect temporary file %s for writing CIB",
+                   tmp_cib);
+        exit_rc = pcmk_err_cib_save;
+        goto cleanup;
+    }
+
+    /* Write out the CIB */
+    if (write_xml_fd(cib_root, tmp_cib, fd, FALSE) <= 0) {
+        crm_err("Changes couldn't be written to %s", tmp_cib);
+        exit_rc = pcmk_err_cib_save;
+        goto cleanup;
+    }
+
+    /* Calculate CIB digest */
+    digest = calculate_on_disk_digest(cib_root);
+    CRM_ASSERT(digest != NULL);
+    crm_info("Wrote version %s.%s.0 of the CIB to disk (digest: %s)",
+             (admin_epoch ? admin_epoch : "0"), (epoch ? epoch : "0"), digest);
+
+    /* Write the CIB digest to a temporary file */
+    fd = mkstemp(tmp_digest);
+    if (fd < 0) {
+        crm_perror(LOG_ERR, "Could not create temporary file for CIB digest");
+        exit_rc = pcmk_err_cib_save;
+        goto cleanup;
+    }
+    if (cib_do_chown && (fchown(fd, cib_file_owner, cib_file_group) < 0)) {
+        crm_perror(LOG_ERR, "Couldn't protect temporary file %s for writing CIB",
+                   tmp_cib);
+        exit_rc = pcmk_err_cib_save;
+        close(fd);
+        goto cleanup;
+    }
+    rc = pcmk__write_sync(fd, digest);
+    if (rc != pcmk_rc_ok) {
+        crm_err("Could not write digest to %s: %s",
+                tmp_digest, pcmk_rc_str(rc));
+        exit_rc = pcmk_err_cib_save;
+        close(fd);
+        goto cleanup;
+    }
+    close(fd);
+    crm_debug("Wrote digest %s to disk", digest);
+
+    /* Verify that what we wrote is sane */
+    crm_info("Reading cluster configuration file %s (digest: %s)",
+             tmp_cib, tmp_digest);
+    rc = cib_file_read_and_verify(tmp_cib, tmp_digest, NULL);
+    CRM_ASSERT(rc == 0);
+
+    /* Rename temporary files to live, and sync directory changes to media */
+    crm_debug("Activating %s", tmp_cib);
+    if (rename(tmp_cib, cib_path) < 0) {
+        crm_perror(LOG_ERR, "Couldn't rename %s as %s", tmp_cib, cib_path);
+        exit_rc = pcmk_err_cib_save;
+    }
+    if (rename(tmp_digest, digest_path) < 0) {
+        crm_perror(LOG_ERR, "Couldn't rename %s as %s", tmp_digest,
+                   digest_path);
+        exit_rc = pcmk_err_cib_save;
+    }
+    pcmk__sync_directory(cib_dirname);
+
+  cleanup:
+    free(cib_path);
+    free(digest_path);
+    free(digest);
+    free(tmp_digest);
+    free(tmp_cib);
+    return exit_rc;
+}