cib_file.c

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/*
 * Original copyright 2004 International Business Machines
 * Later changes copyright 2008-2020 the Pacemaker project contributors
 *
 * 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 <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>

#define CIB_FLAG_DIRTY 0x00001
#define CIB_FLAG_LIVE  0x00002

typedef struct cib_file_opaque_s {
    int flags;
    char *filename;

} cib_file_opaque_t;

int cib_file_perform_op(cib_t * cib, const char *op, const char *host, const char *section,
                        xmlNode * data, xmlNode ** output_data, int call_options);

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 cib_file_signon(cib_t * cib, const char *name, enum cib_conn_type type);
int cib_file_signoff(cib_t * cib);
int cib_file_free(cib_t * cib);

static int
cib_file_inputfd(cib_t * cib)
{
    return -EPROTONOSUPPORT;
}

static int
cib_file_set_connection_dnotify(cib_t * cib, void (*dnotify) (gpointer user_data))
{
    return -EPROTONOSUPPORT;
}

static int
cib_file_register_notification(cib_t * cib, const char *callback, int enabled)
{
    return -EPROTONOSUPPORT;
}

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;
}

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;
}

#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"

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;
}

/* 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;

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;
}

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");
    crm_xml_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);
    }
}

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;
}

cib_t *
cib_file_new(const char *cib_location)
{
    cib_file_opaque_t *private = NULL;
    cib_t *cib = cib_new_variant();

    private = calloc(1, sizeof(cib_file_opaque_t));
    CRM_ASSERT((cib != NULL) && (private != NULL));

    cib->variant = cib_file;
    cib->variant_opaque = private;

    if (cib_location == NULL) {
        cib_location = getenv("CIB_file");
    }
    private->flags = 0;
    if (cib_file_is_live(cib_location)) {
        set_bit(private->flags, CIB_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;

    return cib;
}

static xmlNode *in_mem_cib = NULL;

static int
load_file_cib(const char *filename)
{
    struct stat buf;
    xmlNode *root = NULL;

    /* Ensure file is readable */
    if (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;
}

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;
}

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;
}

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 (is_set(private->flags, CIB_FLAG_DIRTY)) {

        /* If this is the live CIB, write it out with a digest */
        if (is_set(private->flags, CIB_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);
            clear_bit(private->flags, CIB_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;
}

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;
}

struct cib_func_entry {
    const char *op;
    gboolean read_only;
    cib_op_t fn;
};

/* *INDENT-OFF* */
static struct cib_func_entry cib_file_ops[] = {
    {CIB_OP_QUERY,      TRUE,  cib_process_query},
    {CIB_OP_MODIFY,     FALSE, cib_process_modify},
    {CIB_OP_APPLY_DIFF, FALSE, cib_process_diff},
    {CIB_OP_BUMP,       FALSE, cib_process_bump},
    {CIB_OP_REPLACE,    FALSE, cib_process_replace},
    {CIB_OP_CREATE,     FALSE, cib_process_create},
    {CIB_OP_DELETE,     FALSE, cib_process_delete},
    {CIB_OP_ERASE,      FALSE, cib_process_erase},
    {CIB_OP_UPGRADE,    FALSE, cib_process_upgrade},
};
/* *INDENT-ON* */

int
cib_file_perform_op(cib_t * cib, const char *op, const char *host, const char *section,
                    xmlNode * data, xmlNode ** output_data, int call_options)
{
    return cib_file_perform_op_delegate(cib, op, host, section, data, output_data, call_options,
                                        NULL);
}

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 = DIMOF(cib_file_ops);
    cib_file_opaque_t *private = cib->variant_opaque;

#if ENABLE_ACL
    crm_info("Handling %s operation for %s as %s",
             (op? op : "invalid"), (section? section : "entire CIB"),
             (user_name? user_name : "default user"));
#else
    crm_info("Handling %s operation for %s",
             (op? op : "invalid"), (section? section : "entire CIB"));
#endif

    call_options |= (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 (safe_str_eq(op, cib_file_ops[lpc].op)) {
            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, "dummy-token", op, host, section, data, call_options, user_name);
#if ENABLE_ACL
    if(user_name) {
        crm_xml_add(request, XML_ACL_TAG_USER, user_name);
    }
#endif

    /* Mirror the logic in cib_prepare_common() */
    if (section != NULL && data != NULL && crm_str_eq(crm_element_name(data), XML_TAG_CIB, TRUE)) {
        data = get_object_root(section, data);
    }

    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) {
        xml_log_patchset(LOG_DEBUG, "cib:diff", cib_diff);
        free_xml(in_mem_cib);
        in_mem_cib = result_cib;
        set_bit(private->flags, CIB_FLAG_DIRTY);
    }

    free_xml(cib_diff);

    if (cib->op_callback != NULL) {
        cib->op_callback(NULL, cib->call_id, rc, output);
    }

    if (output_data && output) {
        if(output == in_mem_cib) {
            *output_data = copy_xml(output);
        } else {
            *output_data = output;
        }

    } else if(output != in_mem_cib) {
        free_xml(output);
    }

    free(effective_user);
    return rc;
}