myxce/src/controller/config_repl.c

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#define _GNU_SOURCE
#include "config_repl.h"
#include <dirent.h>
#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#include <netdb.h>
#include <openssl/err.h>
#include <openssl/sha.h>
#include <openssl/ssl.h>
#include <poll.h>
#include <pthread.h>
#include <stdatomic.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <time.h>
#include <utime.h>
#include <unistd.h>
#include <inttypes.h>
#include "byteorder.h"
#include "clusterconfig.h"
#include "cluster.h"
#include "controller.capnp.h" /* OPCode_upgradeConfigAck, OPCode_walCatchupEntry */
#include "ha.h"
#include "netio.h" /* endpoint_t, xce_request() */
#include "repl.h" /* repl_wait_majority_ack, repl_on_config_ack */
#include "request.h" /* xce_request, xce_reply, init_reply_by_req */
#include "utils.h"
#include "wobj.h"
#include "xce/cluster_def.h"
#include "wal_types.h" /* wal_entry_hdr_t, WAL_* constants */
/* xce_request: defined in request.c, not yet in any public header */
extern int xce_request(endpoint_t *ep, xce_request_t *req);
/* SSL context for xce_probe_config_tag — set by bootstrap_config_if_needed.
* Stored as void* to avoid SSL_CTX type at this point in the translation unit. */
static void *s_probe_ssl_ctx = NULL;
/* ── config load helpers (shared with myconf.c logic) ─────── */
#define SET_DEFAULT_IF_UNSET(var, unset, val) \
do { \
if ((var) == (unset)) { \
(var) = (val); \
} \
} while (0)
static void fill_default_cluster_config(cluster_config_t *c)
{
SET_DEFAULT_IF_UNSET(c->port, 0, 9990);
SET_DEFAULT_IF_UNSET(c->heartbeat_interval, 0, 5);
SET_DEFAULT_IF_UNSET(c->fetch_job_interval, 0, 10);
}
static int load_cluster_config_from_file(char *file, cluster_config_t **config)
{
struct capn c;
ClusterConfig_ptr p;
FILE *fp;
int rc = 0;
fp = fopen(file, "rb");
if (fp == NULL) {
rc = -errno;
return rc;
}
capn_init_fp(&c, fp, 0);
p.p = capn_getp(capn_root(&c), 0, 1);
decode_ClusterConfig_ptr(config, p);
capn_free(&c);
fclose(fp);
return 0;
}
/* ── load_primary_config ────────────────────────── */
int load_primary_config(cluster_t *c)
{
myconf_t *myconf = c->myconf;
/* Build conf dir path: <workdir>/<name> */
char conf_dir[4096];
snprintf(conf_dir, sizeof(conf_dir), "%s/%s",
myconf->workdir, myconf->name);
/* Resolve conf/current → versioned filename */
char fname[256] = {0};
int rc = conf_read_current_filename(conf_dir, fname, sizeof(fname));
if (rc != 0) {
INFO("No config at '%s/conf/current' (rc=%d) — "
"will fetch from primary after election",
conf_dir, rc);
return -ENOENT;
}
/* Heap-allocate conffile so it survives past this stack frame */
free(myconf->conffile);
myconf->conffile = NULL;
if (asprintf(&myconf->conffile, "%s/conf/%s", conf_dir, fname) < 0)
return -ENOMEM;
/* Read raw bytes and check size */
uint8_t *bytes = NULL;
size_t blen = 0;
rc = conf_read_raw(myconf->conffile, &bytes, &blen);
if (rc != 0) {
ERROR("Primary config '%s' unreadable: %d", myconf->conffile, rc);
free(myconf->conffile);
myconf->conffile = NULL;
return rc;
}
/* Compute and cache SHA-256 */
SHA256(bytes, blen, myconf->config_sha256);
uint64_t tag;
memcpy(&tag, myconf->config_sha256, 8);
myconf->config_version_tag = be64toh(tag);
/* Free any prior decoded config before overwriting the pointer */
if (myconf->cluster_config) {
free_ClusterConfig(myconf->cluster_config);
free(myconf->cluster_config);
myconf->cluster_config = NULL;
}
/* Decode Cap'n Proto directly into myconf->cluster_config */
rc = load_cluster_config_from_file(myconf->conffile,
&myconf->cluster_config);
if (rc != 0) {
ERROR("Primary config '%s' failed Cap'n Proto decode: %d",
myconf->conffile, rc);
free(bytes);
free(myconf->conffile);
myconf->conffile = NULL;
return rc;
}
if (myconf->cluster_config == NULL) {
ERROR("Primary config '%s' decoded to NULL", myconf->conffile);
free(bytes);
free(myconf->conffile);
myconf->conffile = NULL;
return -EINVAL;
}
free(bytes);
fill_default_cluster_config(myconf->cluster_config);
/* Check for reserved lost_and_found name */
if (config_contains_reserved_name(myconf->cluster_config)) {
ERROR("Config '%s' contains reserved name 'lost_and_found'",
myconf->conffile);
free_ClusterConfig(myconf->cluster_config);
free(myconf->cluster_config);
myconf->cluster_config = NULL;
free(myconf->conffile);
myconf->conffile = NULL;
return -EINVAL;
}
/* Default generation to 1 if not set */
if (myconf->cluster_config->config_generation == 0)
myconf->cluster_config->config_generation = 1;
myconf->config_generation = myconf->cluster_config->config_generation;
/* Check staleness */
myconf->conf_stale = conf_check_stale(conf_dir, myconf->conf_stale_timeout);
if (myconf->conf_stale)
WARN("Primary config appears stale (age > %lds)",
(long)myconf->conf_stale_timeout);
INFO("Primary config loaded: tag=%016" PRIx64 " gen=%" PRIu64,
myconf->config_version_tag, myconf->config_generation);
return 0;
}
/* ── internal helpers ──────────────────────────── */
static void make_conf_dir(const char *workdir, char *out, size_t sz)
{
snprintf(out, sz, "%s/conf", workdir);
}
static void bytes_to_hex(const uint8_t *b, size_t n, char *out)
{
static const char hex[] = "0123456789abcdef";
for (size_t i = 0; i < n; i++) {
out[2 * i] = hex[(b[i] >> 4) & 0xf];
out[2 * i + 1] = hex[b[i] & 0xf];
}
out[2 * n] = '\0';
}
/* ── conf_read_current_filename ─────────────────── */
int conf_read_current_filename(const char *workdir, char *out, size_t outsz)
{
char head_path[4096];
snprintf(head_path, sizeof(head_path), "%s/conf/current", workdir);
FILE *f = fopen(head_path, "r");
if (!f)
return -ENOENT;
struct stat st;
if (fstat(fileno(f), &st) == 0 && st.st_size == 0) {
fclose(f);
ERROR("conf/current is empty — treating as missing config (pointer file"
" may be from an interrupted write)");
return -ENODATA;
}
if (!fgets(out, (int)outsz, f)) {
fclose(f);
return -EIO;
}
fclose(f);
out[strcspn(out, "\n")] = '\0';
if (strchr(out, '/')) {
ERROR("conf/current contains path separator — corrupted pointer file");
return -EINVAL;
}
if (strncmp(out, "cluster.bin.", 12) != 0) {
ERROR("conf/current '%s' does not start with 'cluster.bin.'", out);
return -EINVAL;
}
const char *hex = out + 12;
if (strlen(hex) != 12 || strspn(hex, "0123456789abcdef") != 12) {
ERROR("conf/current suffix '%s' is not 12 lowercase hex chars", hex);
return -EINVAL;
}
return 0;
}
/* ── conf_save_config ───────────────────────────── */
int conf_save_config(myconf_t *myconf, const uint8_t *bytes, size_t len,
const uint8_t sha256[32])
{
/* effective_dir = workdir/name — must match load_primary_config() path */
char effective_dir[4096];
snprintf(effective_dir, sizeof(effective_dir), "%s/%s",
myconf->workdir, myconf->name);
char conf_dir[4096];
make_conf_dir(effective_dir, conf_dir, sizeof(conf_dir));
if (mkdir(conf_dir, 0700) != 0 && errno != EEXIST)
return -errno;
/* Derive 12-char hex tag from first 6 bytes of SHA-256 */
char hex_tag[13];
bytes_to_hex(sha256, 6, hex_tag);
/* Step 1: write versioned file via thread-unique .tmp */
char tmp_path[4096], ver_path[4096];
snprintf(tmp_path, sizeof(tmp_path), "%s/cluster.bin.%s.%lu.tmp",
conf_dir, hex_tag, (unsigned long)pthread_self());
snprintf(ver_path, sizeof(ver_path), "%s/cluster.bin.%s",
conf_dir, hex_tag);
int fd = open(tmp_path, O_WRONLY | O_CREAT | O_TRUNC, 0600);
if (fd < 0)
return -errno;
if (write(fd, bytes, len) != (ssize_t)len) {
close(fd);
unlink(tmp_path);
return -EIO;
}
if (fsync(fd) != 0) {
close(fd);
unlink(tmp_path);
return -EIO;
}
close(fd);
if (rename(tmp_path, ver_path) != 0) {
unlink(tmp_path);
return -errno;
}
/* Step 2: update HEAD pointer via thread-unique .tmp */
char ptr_tmp[4096], ptr_path[4096];
snprintf(ptr_tmp, sizeof(ptr_tmp), "%s/current.%lu.tmp",
conf_dir, (unsigned long)pthread_self());
snprintf(ptr_path, sizeof(ptr_path), "%s/current", conf_dir);
char target[NAME_MAX];
snprintf(target, sizeof(target), "cluster.bin.%s\n", hex_tag);
fd = open(ptr_tmp, O_WRONLY | O_CREAT | O_TRUNC, 0600);
if (fd < 0)
return -errno;
if (write(fd, target, strlen(target)) != (ssize_t)strlen(target)) {
close(fd);
unlink(ptr_tmp);
return -EIO;
}
if (fsync(fd) != 0) {
close(fd);
unlink(ptr_tmp);
return -EIO;
}
close(fd);
if (rename(ptr_tmp, ptr_path) != 0) {
unlink(ptr_tmp);
return -errno;
}
/* Step 2.5: fsync conf/ directory to persist the rename(2)s */
fd = open(conf_dir, O_RDONLY);
if (fd >= 0) {
fsync(fd);
close(fd);
}
/* Step 3: trim old versions */
conf_trim_old_versions(effective_dir, myconf->conf_keep_n);
/* Update conffile to the new versioned path (heap-allocated) */
free(myconf->conffile);
if (asprintf(&myconf->conffile, "%s/cluster.bin.%s", conf_dir, hex_tag) < 0)
return -ENOMEM;
/* Update tag (first 8 bytes of sha256, host order) and full hash */
uint64_t new_tag;
memcpy(&new_tag, sha256, 8);
myconf->config_version_tag = be64toh(new_tag);
memcpy(myconf->config_sha256, sha256, 32);
return 0;
}
/* ── conf_read_raw ──────────────────────────────── */
int conf_read_raw(const char *conffile, uint8_t **bytes, size_t *len)
{
FILE *f = fopen(conffile, "rb");
if (!f)
return -errno;
if (fseek(f, 0, SEEK_END) != 0) {
fclose(f);
return -EIO;
}
long sz = ftell(f);
if (sz < 0) {
fclose(f);
return -EIO;
}
if (fseek(f, 0, SEEK_SET) != 0) {
fclose(f);
return -EIO;
}
if (sz == 0) {
fclose(f);
ERROR("Config file '%s' is empty — not a valid ClusterConfig blob",
conffile);
return -EIO;
}
if ((size_t)sz > CONF_MAX_SIZE) {
fclose(f);
ERROR("Config file '%s' exceeds CONF_MAX_SIZE (%zu bytes)",
conffile, (size_t)sz);
return -EFBIG;
}
*bytes = (uint8_t *)malloc((size_t)sz);
if (!*bytes) {
fclose(f);
return -ENOMEM;
}
if (fread(*bytes, 1, (size_t)sz, f) != (size_t)sz) {
free(*bytes);
*bytes = NULL;
fclose(f);
return -EIO;
}
fclose(f);
*len = (size_t)sz;
return 0;
}
/* ── conf_get_saved_tag ─────────────────────────── */
uint64_t conf_get_saved_tag(const char *workdir)
{
char fname[256] = {0};
if (conf_read_current_filename(workdir, fname, sizeof(fname)) != 0)
return 0;
char ver_path[4096];
snprintf(ver_path, sizeof(ver_path), "%s/conf/%s", workdir, fname);
uint8_t *bytes = NULL;
size_t blen = 0;
if (conf_read_raw(ver_path, &bytes, &blen) != 0)
return 0;
uint8_t sha256[32];
SHA256(bytes, blen, sha256);
free(bytes);
uint64_t tag;
memcpy(&tag, sha256, 8);
return be64toh(tag);
}
/* ── conf_check_stale ───────────────────────────── */
int conf_check_stale(const char *workdir, time_t stale_timeout_s)
{
if (stale_timeout_s == 0)
return 0;
char fname[256] = {0};
if (conf_read_current_filename(workdir, fname, sizeof(fname)) != 0)
return 0;
char ver_path[4096];
snprintf(ver_path, sizeof(ver_path), "%s/conf/%s", workdir, fname);
struct stat st;
if (stat(ver_path, &st) != 0)
return 0;
time_t age = time(NULL) - st.st_mtime;
return (age > stale_timeout_s) ? 1 : 0;
}
/* ── conf_trim_old_versions ─────────────────────── */
typedef struct {
char name[NAME_MAX];
time_t mtime;
} ver_entry_t;
static int ver_entry_cmp_desc(const void *a, const void *b)
{
const ver_entry_t *ea = (const ver_entry_t *)a;
const ver_entry_t *eb = (const ver_entry_t *)b;
if (eb->mtime > ea->mtime) return 1;
if (eb->mtime < ea->mtime) return -1;
return 0;
}
void conf_trim_old_versions(const char *workdir, int keep_n)
{
char conf_dir[4096];
make_conf_dir(workdir, conf_dir, sizeof(conf_dir));
/* Read current pointer to protect it from deletion */
char current_name[256] = {0};
if (conf_read_current_filename(workdir, current_name, sizeof(current_name)) != 0) {
/* No current pointer — nothing safe to trim without risking deleting the active file */
return;
}
ver_entry_t entries[256];
int n = 0;
DIR *d = opendir(conf_dir);
if (!d)
return;
struct dirent *e;
while ((e = readdir(d)) != NULL && n < 256) {
if (strncmp(e->d_name, "cluster.bin.", 12) != 0)
continue;
if (strstr(e->d_name, ".tmp") != NULL) {
char full[4096];
snprintf(full, sizeof(full), "%s/%s", conf_dir, e->d_name);
unlink(full);
continue;
}
char full[4096];
snprintf(full, sizeof(full), "%s/%s", conf_dir, e->d_name);
struct stat st;
if (stat(full, &st) == 0) {
strncpy(entries[n].name, e->d_name, NAME_MAX - 1);
entries[n].name[NAME_MAX - 1] = '\0';
entries[n].mtime = st.st_mtime;
n++;
}
}
closedir(d);
/* Sort descending by mtime (newest first) */
qsort(entries, (size_t)n, sizeof(entries[0]), ver_entry_cmp_desc);
/* Delete everything after keep_n, protecting the current pointer */
for (int i = keep_n; i < n; i++) {
if (strcmp(entries[i].name, current_name) == 0)
continue;
char full[4096];
snprintf(full, sizeof(full), "%s/%s", conf_dir, entries[i].name);
unlink(full);
}
}
/* ── config_contains_reserved_name ─────────────── */
int config_contains_reserved_name(cluster_config_t *cfg)
{
if (!cfg)
return 0;
/* Check queue names — xce_queue_t.queue is the queue name field */
for (int i = 0; i < cfg->nqueues; i++) {
if (cfg->queues[i] &&
cfg->queues[i]->queue &&
strcmp(cfg->queues[i]->queue, XCE_LOST_AND_FOUND_NAME) == 0)
return 1;
}
/* Check host config names — xce_hostconfig_t.name */
for (int i = 0; i < cfg->nhconfigs; i++) {
if (cfg->hconfigs[i] &&
cfg->hconfigs[i]->name &&
strcmp(cfg->hconfigs[i]->name, XCE_LOST_AND_FOUND_NAME) == 0)
return 1;
}
return 0;
}
/* ── load_primary_config_for_test ───────────────── */
#ifdef XCE_TESTING
int load_primary_config_for_test(cluster_t *c)
{
myconf_t *myconf = c->myconf;
char conf_dir[4096];
snprintf(conf_dir, sizeof(conf_dir), "%s/%s", myconf->workdir, myconf->name);
char fname[256] = {0};
int rc = conf_read_current_filename(conf_dir, fname, sizeof(fname));
if (rc != 0)
return rc;
free(myconf->conffile);
myconf->conffile = NULL;
if (asprintf(&myconf->conffile, "%s/conf/%s", conf_dir, fname) < 0)
return -ENOMEM;
return 0;
}
#endif
/* ── create_lost_and_found ──────────────────────── */
void create_lost_and_found(cluster_t *c)
{
if (!c->qmgr || !c->workermgr)
return;
#ifndef XCE_TESTING
/* key_find, create_queue, and makeWorker require librtti + queue.c which
* are not linked into the unit test binary. The !qmgr guard above means
* this block is unreachable in tests regardless. */
/* Synthetic queue — receives jobs whose queue was removed by a config
* upgrade. Created before persist_recover() so WAL replay can route
* unknown queue IDs here instead of failing. */
{
void *existing = NULL;
if (key_find(c->qmgr, (void *)XCE_LOST_AND_FOUND_NAME, &existing) <= 0) {
xce_queue_t lf = {0};
lf.queue = XCE_LOST_AND_FOUND_NAME;
queue_t *q = create_queue(c, &lf);
if (q)
INFO("Created synthetic 'lost_and_found' queue");
else
ERROR("Failed to create synthetic 'lost_and_found' queue");
}
}
/* Synthetic host — receives jobs whose host was removed by a config
* upgrade. Uses makeWorker directly; no hostconfig entry is required
* for this sentinel host. */
{
void *existing = NULL;
if (key_find(c->workermgr, (void *)XCE_LOST_AND_FOUND_NAME, &existing) <= 0) {
hostattrs_t lf_attrs = { .hosttype = XCE_LOST_AND_FOUND_NAME,
.hostmodel = XCE_LOST_AND_FOUND_NAME };
xce_worker_t lf_host = { .name = XCE_LOST_AND_FOUND_NAME,
.attrs = &lf_attrs };
worker_t *w = makeWorker(c->workermgr, &lf_host);
if (w)
INFO("Created synthetic 'lost_and_found' host");
else
ERROR("Failed to create synthetic 'lost_and_found' host");
}
}
#endif /* XCE_TESTING */
}
/* ── handle_config_request ──────────────────────── */
int handle_config_request(cluster_t *c, endpoint_t *ep, xce_request_t *req)
{
uint64_t their_tag = req->body.replconfigrequestmsg->version_tag;
uint64_t my_tag = c->myconf->config_version_tag;
xce_reply_t reply;
init_reply_by_req(&reply, req);
reply.data_which = RequestReply_data_replconfigreplymsg;
repl_config_reply_t *rmsg = (repl_config_reply_t *)calloc(
1, sizeof(repl_config_reply_t));
if (!rmsg) {
reply.status = -ENOMEM;
reply.data_which = RequestReply_data_nodata;
xce_reply(ep, c->myhost, &reply);
return -ENOMEM;
}
reply.data.replconfigreplymsg = rmsg;
if (their_tag == my_tag) {
reply.status = 0;
rmsg->up_to_date = 1;
rmsg->version_tag = 0;
rmsg->sha256 = NULL;
rmsg->bytes = NULL;
xce_reply(ep, c->myhost, &reply);
free(rmsg);
reply.data.replconfigreplymsg = NULL;
return 0;
}
/* Read raw config bytes */
uint8_t *bytes = NULL;
size_t blen = 0;
int rc = conf_read_raw(c->myconf->conffile, &bytes, &blen);
if (rc != 0) {
ERROR("handle_config_request: conf_read_raw failed: %d", rc);
reply.status = rc;
reply.data_which = RequestReply_data_nodata;
free(rmsg);
reply.data.replconfigreplymsg = NULL;
xce_reply(ep, c->myhost, &reply);
return rc;
}
/* Verify SHA-256 matches what we cached at startup */
uint8_t recomputed[32];
SHA256(bytes, blen, recomputed);
if (memcmp(recomputed, c->myconf->config_sha256, 32) != 0) {
ERROR("handle_config_request: config file changed since startup"
" — refusing to send (hash mismatch)");
free(bytes);
free(rmsg);
reply.data.replconfigreplymsg = NULL;
reply.status = -EIO;
reply.data_which = RequestReply_data_nodata;
xce_reply(ep, c->myhost, &reply);
return -EIO;
}
int rc2 = xce_replconfig_reply_raw(ep, c->myhost, req->seq,
my_tag,
recomputed, 32,
bytes, blen);
free(bytes);
/* rmsg is no longer needed — xce_replconfig_reply_raw builds capnp directly */
free(rmsg);
reply.data.replconfigreplymsg = NULL;
if (rc2 != 0)
ERROR("handle_config_request: xce_replconfig_reply_raw failed: %d", rc2);
return rc2;
}
/* ── fetch_config_from_primary helpers ─────────────────────── */
/*
* connect_ssl_raw: open a non-blocking TCP connection to host:port, then
* perform a TLS handshake using ssl_ctx.
*
* The poll loop checks ha_is_primary(ha) between iterations: if this node
* is promoted to primary while waiting, the function returns -ECANCELED so
* the caller can switch to the primary path immediately.
*
* On success: *out_ssl and *out_sock are set; caller owns them and must call
* SSL_shutdown(ssl) + SSL_free(ssl) + close(sock).
* On failure: nothing is left open; returns negative errno.
*/
static int connect_ssl_raw(SSL_CTX *ssl_ctx, const char *host, uint32_t port,
int poll_timeout_ms, const ha_state_t *ha,
SSL **out_ssl, int *out_sock)
{
struct addrinfo hints, *res = NULL;
memset(&hints, 0, sizeof(hints));
hints.ai_family = AF_UNSPEC;
hints.ai_socktype = SOCK_STREAM;
char port_str[16];
snprintf(port_str, sizeof(port_str), "%u", (unsigned)port);
if (getaddrinfo(host, port_str, &hints, &res) != 0)
return -ENONET;
int sock = socket(res->ai_family, res->ai_socktype, res->ai_protocol);
if (sock < 0) {
int e = errno;
freeaddrinfo(res);
return -e;
}
/* Non-blocking connect */
int flags = fcntl(sock, F_GETFL, 0);
fcntl(sock, F_SETFL, flags | O_NONBLOCK);
connect(sock, res->ai_addr, res->ai_addrlen);
freeaddrinfo(res);
res = NULL;
/* Poll loop: check ha_is_primary between iterations */
while (!ha_is_primary(ha)) {
struct pollfd pfd = { .fd = sock, .events = POLLOUT | POLLERR | POLLHUP };
int pr = poll(&pfd, 1, poll_timeout_ms);
if (pr < 0 && errno == EINTR)
continue;
if (pr == 0) {
close(sock);
return -ETIMEDOUT;
}
if (pfd.revents & (POLLERR | POLLHUP)) {
close(sock);
return -ECONNREFUSED;
}
if (pfd.revents & POLLOUT)
break;
}
if (ha_is_primary(ha)) {
close(sock);
return -ECANCELED;
}
/* Verify connect succeeded */
{
int err = 0;
socklen_t el = sizeof(err);
getsockopt(sock, SOL_SOCKET, SO_ERROR, &err, &el);
if (err != 0) {
close(sock);
return -err;
}
}
/* Restore blocking for SSL handshake */
fcntl(sock, F_SETFL, flags & ~O_NONBLOCK);
SSL *ssl = SSL_new(ssl_ctx);
if (!ssl) {
close(sock);
return -ENOMEM;
}
SSL_set_fd(ssl, sock);
int sr;
do {
sr = SSL_connect(ssl);
if (sr <= 0) {
int e = SSL_get_error(ssl, sr);
if (e != SSL_ERROR_WANT_READ && e != SSL_ERROR_WANT_WRITE)
break;
}
} while (sr <= 0 && !ha_is_primary(ha));
if (sr <= 0 || ha_is_primary(ha)) {
SSL_free(ssl);
close(sock);
return -ECONNRESET;
}
*out_ssl = ssl;
*out_sock = sock;
return 0;
}
/*
* do_one_config_fetch: attempt one network fetch of the ClusterConfig from
* the primary controller over a standalone SSL socket.
*
* Steps:
* 1. Open non-blocking TCP + SSL handshake via connect_ssl_raw()
* 2. Send OP_replConfig request with our current version tag
* 3. Decode the reply
* 4. If up_to_date: nothing to save — return 0
* 5. Verify SHA-256 integrity of received bytes
* 6. Save to disk via conf_save_config()
* 7. Reload cluster_config via load_primary_config()
* 8. Log success and clean up
*
* Returns 0 on success (config up-to-date or freshly saved+loaded).
* Returns -ECANCELED if promoted to primary during the attempt (caller should
* switch to primary path). Returns other negative errno on transient failure
* (caller will retry with backoff).
*/
static int do_one_config_fetch(cluster_t *c, const char *host, uint32_t port,
uint64_t our_tag)
{
SSL *ssl = NULL;
int sock = -1;
/* 1. Connect + SSL handshake */
int rc = connect_ssl_raw(
(SSL_CTX *)c->ha.ssl_ctx, host, port,
(int)c->ha.config.probe_connect_timeout_ms,
&c->ha, &ssl, &sock);
if (rc != 0)
return rc;
/* 2. Send OP_replConfig request */
rc = xce_replconfig_req_ssl(ssl, our_tag);
if (rc != 0) {
SSL_shutdown(ssl);
SSL_free(ssl);
close(sock);
return rc;
}
/* 3. Decode reply */
int up_to_date = 0;
uint64_t new_tag = 0;
uint8_t *sha256 = NULL;
uint8_t *config_bytes = NULL;
size_t config_len = 0;
rc = xce_replconfig_reply_ssl_decode(ssl, &up_to_date, &new_tag,
&sha256, &config_bytes, &config_len);
if (rc != 0) {
SSL_shutdown(ssl);
SSL_free(ssl);
close(sock);
return rc;
}
/* 4. Up-to-date fast path: our tag matches primary — nothing to save */
if (up_to_date) {
SSL_shutdown(ssl);
SSL_free(ssl);
close(sock);
return 0;
}
/* 5. Verify SHA-256 integrity */
uint8_t computed[32];
SHA256(config_bytes, config_len, computed);
if (memcmp(computed, sha256, 32) != 0) {
ERROR("HA: config fetch SHA-256 mismatch from primary — retrying");
free(sha256);
free(config_bytes);
SSL_shutdown(ssl);
SSL_free(ssl);
close(sock);
return -EBADMSG;
}
/* 6. Save to disk atomically */
rc = conf_save_config(c->myconf, config_bytes, config_len, sha256);
free(sha256);
free(config_bytes);
sha256 = NULL;
config_bytes = NULL;
if (rc != 0) {
SSL_shutdown(ssl);
SSL_free(ssl);
close(sock);
return rc;
}
/* 7. Reload cluster_config from the newly saved file */
rc = load_primary_config(c);
if (rc != 0) {
SSL_shutdown(ssl);
SSL_free(ssl);
close(sock);
return rc;
}
/* 8. Log success */
INFO("HA: config received from primary (tag=%016" PRIx64 ")",
c->myconf->config_version_tag);
/* Clean up SSL and socket */
SSL_shutdown(ssl);
SSL_free(ssl);
close(sock);
return 0;
}
/* ── fetch_config_from_primary ──────────────────── */
int fetch_config_from_primary(cluster_t *c)
{
const xce_cluster_config_t *pcfg = &c->myconf->peers_cfg;
/* Build conf dir path: <workdir>/<name> */
char conf_dir[4096];
snprintf(conf_dir, sizeof(conf_dir), "%s/%s",
c->myconf->workdir, c->myconf->name);
uint64_t saved_tag = conf_get_saved_tag(conf_dir);
if (pcfg->candidates_count == 0) {
/* Single-node mode — no primary to contact; load from saved file */
goto use_saved;
}
{
/* Primary is candidates[0] (highest priority = lowest index) */
const char *primary_host = pcfg->candidates[0].hostname;
uint32_t primary_port = pcfg->candidates[0].port;
INFO("HA: requesting config from primary %s:%u (my_tag=%016" PRIx64 ")",
primary_host, primary_port, saved_tag);
uint32_t delay_ms = 500;
const uint32_t max_delay_ms = 5000;
const int max_attempts = 60; /* up to 5min: primary may still be initializing */
for (int attempt = 0; attempt < max_attempts; attempt++) {
/* If promoted during retry, switch to primary path */
if (ha_is_primary(&c->ha)) {
INFO("HA: promoted to primary during config fetch"
" — switching to primary path");
return load_primary_config(c);
}
int rc = do_one_config_fetch(c, primary_host, primary_port,
saved_tag);
if (rc == 0) {
INFO("HA: config received from primary"
" (tag=%016" PRIx64 ")",
c->myconf->config_version_tag);
return 0;
}
if (attempt < max_attempts - 1) {
WARN("HA: config fetch attempt %d/%d failed (rc=%d)"
" — retrying in %ums",
attempt + 1, max_attempts, rc, delay_ms);
usleep((useconds_t)delay_ms * 1000);
delay_ms = delay_ms * 2 < max_delay_ms
? delay_ms * 2 : max_delay_ms;
}
}
}
use_saved:
{
char fname[256] = {0};
int rc = conf_read_current_filename(conf_dir, fname, sizeof(fname));
if (rc != 0) {
ERROR("Standby (priority=%d) could not fetch config from primary"
" and has no saved config at '%s/conf/current'"
" — start the primary first or provision config manually",
c->ha.my_priority, conf_dir);
return -ENOENT;
}
WARN("HA: using saved config (tag=%016" PRIx64 ")"
" — config may be stale", saved_tag);
/* load_primary_config resolves conf/current → versioned file,
* decodes Cap'n Proto, computes SHA-256, and checks staleness.
* It is reused here since the saved-config load path is identical. */
return load_primary_config(c);
}
}
/* ── send_upgrade_error ─────────────────────────── */
static void send_upgrade_error(endpoint_t *ep, xce_request_t *req,
cluster_t *c, const char *msg)
{
xce_reply_t reply;
init_reply_by_req(&reply, req);
reply.status = -EINVAL;
reply.data_which = RequestReply_data_nodata;
xce_reply(ep, c->myhost, &reply);
ERROR("OP_upgradeConfig rejected: %s", msg);
}
/* ── push_config_to_standbys ─────────────────────── */
/* push_ctx_t is exposed in config_repl.h under XCE_TESTING so tests can
* construct synthetic contexts. In production builds, define it locally. */
#ifndef XCE_TESTING
typedef struct {
endpoint_t *ep;
xce_peerinfo_t *from;
uint64_t new_tag;
const uint8_t *bytes;
size_t blen;
const uint8_t *sha256;
int acked;
int started;
int done; /* set by push_thread on exit */
} push_ctx_t;
#endif
static void *push_thread(void *arg)
{
push_ctx_t *ctx = (push_ctx_t *)arg;
int rc = xce_replconfigpush_req_raw(
ctx->ep, ctx->from,
ctx->new_tag,
ctx->sha256, 32,
ctx->bytes, ctx->blen);
if (rc == 0)
ctx->acked = 1;
else
WARN("push_config_to_standbys: push to endpoint %p failed: %d", ctx->ep, rc);
ctx->done = 1;
return NULL;
}
/* wait_all_with_timeout: join all push threads within a CLOCK_MONOTONIC deadline.
*
* Polls until all started threads have set ctx->done or the deadline expires,
* then signals *done = 1 (for future callers that check an early-exit flag),
* and joins all started threads (they exit quickly once ctx->done is set).
*
* Returns the number of threads that had acked before the deadline.
*/
static int wait_all_with_timeout(pthread_t *threads, push_ctx_t *ctxs,
int n, uint32_t timeout_ms, atomic_int *done)
{
struct timespec deadline;
clock_gettime(CLOCK_MONOTONIC, &deadline);
deadline.tv_sec += (long)(timeout_ms / 1000);
deadline.tv_nsec += (long)(timeout_ms % 1000) * 1000000L;
if (deadline.tv_nsec >= 1000000000L) {
deadline.tv_sec++;
deadline.tv_nsec -= 1000000000L;
}
/* Poll until deadline or all started threads have set their done flag */
for (;;) {
struct timespec now;
clock_gettime(CLOCK_MONOTONIC, &now);
if (now.tv_sec > deadline.tv_sec ||
(now.tv_sec == deadline.tv_sec &&
now.tv_nsec >= deadline.tv_nsec))
break;
int pending = 0;
for (int i = 0; i < n; i++) {
if (ctxs[i].started && !ctxs[i].done)
pending++;
}
if (pending == 0)
break;
usleep(5000); /* 5ms poll */
}
atomic_store(done, 1); /* signal threads that deadline has passed */
int acked = 0;
for (int i = 0; i < n; i++) {
if (ctxs[i].started) {
pthread_join(threads[i], NULL);
if (ctxs[i].acked)
acked++;
}
}
return acked;
}
#ifdef XCE_TESTING
int wait_all_with_timeout_for_test(pthread_t *threads, push_ctx_t *ctxs,
int n, uint32_t timeout_ms, atomic_int *done)
{
return wait_all_with_timeout(threads, ctxs, n, timeout_ms, done);
}
#endif
int push_config_to_standbys(cluster_t *c, const uint8_t *bytes, size_t blen,
const uint8_t sha256[32], uint64_t new_tag)
{
if (!c->ha.standby_endpoints)
return 0;
pthread_mutex_lock(&c->ha.lock);
int n = c->ha.standby_endpoints->count;
if (n == 0) {
pthread_mutex_unlock(&c->ha.lock);
return 0;
}
push_ctx_t *ctxs = calloc((size_t)n, sizeof(push_ctx_t));
if (!ctxs) {
pthread_mutex_unlock(&c->ha.lock);
return 0;
}
for (int i = 0; i < n; i++) {
ctxs[i].ep = (endpoint_t *)zarray_get(c->ha.standby_endpoints, i);
ctxs[i].from = c->myhost;
ctxs[i].new_tag = new_tag;
ctxs[i].bytes = bytes;
ctxs[i].blen = blen;
ctxs[i].sha256 = sha256;
}
pthread_mutex_unlock(&c->ha.lock);
pthread_t *threads = malloc((size_t)n * sizeof(pthread_t));
if (!threads) {
free(ctxs);
return 0;
}
for (int i = 0; i < n; i++) {
ctxs[i].started = (pthread_create(&threads[i], NULL, push_thread, &ctxs[i]) == 0);
if (!ctxs[i].started)
WARN("push_config_to_standbys: pthread_create failed for standby %d", i);
}
atomic_int push_done;
atomic_init(&push_done, 0);
int acked = wait_all_with_timeout(threads, ctxs, n,
CONF_PUSH_TIMEOUT_MS, &push_done);
free(ctxs);
free(threads);
/* Req 8.1–8.3: wait for majority-quorum OP_upgradeConfigAck.
* On quorum: advance committed_config_tag atomically (Req 8.5). */
int rc = repl_wait_majority_ack(&c->persist.repl, CONF_PUSH_TIMEOUT_MS,
(uint8_t)OPCode_upgradeConfigAck);
if (rc == 0) {
atomic_store_explicit(&c->ha.committed_config_tag, new_tag,
memory_order_release);
INFO("Config committed on majority (tag=%016" PRIx64
", pushed=%d/%d standbys)", new_tag, acked, n);
} else {
WARN("Config push: timeout waiting for majority ACK"
" (tag=%016" PRIx64 ", pushed=%d/%d standbys)",
new_tag, acked, n);
}
return acked;
}
/* ── handle_upgrade_config ──────────────────────── */
/*
* do_upgrade_config_with_bytes: core upgrade logic called after the raw
* capnp bytes have been extracted from the wire via
* xce_upgrade_config_req_extract_raw().
*
* Steps:
* 0. Validate size limits
* 1. Verify transit SHA-256
* 2. Decode into cluster_config_t via temp file + load_cluster_config_from_file
* 3. Reject if reserved name present
* 4. Increment generation, re-encode with updated counter
* 5. Save to disk atomically
* 6. Update in-memory generation
* 7. Push to standbys (best-effort)
* 8. ACK admin tool
* 9. Wait for in-flight checkpoint, then signal restart
*/
static int do_upgrade_config_with_bytes(cluster_t *c, endpoint_t *ep,
xce_request_t *req,
const uint8_t *in_bytes,
size_t in_len,
const uint8_t in_sha[32])
{
/* 0. Validate size */
if (in_len == 0 || in_bytes == NULL || in_sha == NULL) {
send_upgrade_error(ep, req, c, "Missing bytes or sha256 field");
return -EINVAL;
}
if (in_len > CONF_MAX_SIZE) {
send_upgrade_error(ep, req, c, "Config blob exceeds CONF_MAX_SIZE");
return -EINVAL;
}
/* 1. Verify transit SHA-256 */
uint8_t computed[32];
SHA256(in_bytes, in_len, computed);
if (memcmp(computed, in_sha, 32) != 0) {
send_upgrade_error(ep, req, c,
"SHA-256 mismatch -- blob corrupted in transit");
return -EINVAL;
}
/* 2. Write to a temp file and decode via load_cluster_config_from_file().
* This reuses the same decode path as the normal config load and avoids
* direct in-memory capnp buffer manipulation. */
char tmp_path[4096];
snprintf(tmp_path, sizeof(tmp_path), "/tmp/xce_upgrade_cfg.%lu.tmp",
(unsigned long)pthread_self());
int fd = open(tmp_path, O_WRONLY | O_CREAT | O_TRUNC, 0600);
if (fd < 0) {
send_upgrade_error(ep, req, c, "Failed to create temp decode file");
return -errno;
}
if (write(fd, in_bytes, in_len) != (ssize_t)in_len) {
close(fd);
unlink(tmp_path);
send_upgrade_error(ep, req, c, "Failed to write temp decode file");
return -EIO;
}
close(fd);
cluster_config_t *new_cfg = NULL;
int rc = load_cluster_config_from_file(tmp_path, &new_cfg);
unlink(tmp_path);
if (rc != 0 || !new_cfg) {
if (new_cfg) {
free_ClusterConfig(new_cfg);
free(new_cfg);
}
send_upgrade_error(ep, req, c, "Failed to parse Cap'n Proto blob");
return -EINVAL;
}
/* 3. Reject reserved names */
if (config_contains_reserved_name(new_cfg)) {
free_ClusterConfig(new_cfg);
free(new_cfg);
send_upgrade_error(ep, req, c,
"Config contains reserved name 'lost_and_found'");
return -EINVAL;
}
/* 4. Increment generation, re-encode */
uint64_t new_gen = c->myconf->config_generation + 1;
new_cfg->config_generation = new_gen;
struct capn out_cap;
capn_init_malloc(&out_cap);
struct capn_segment *seg = capn_root(&out_cap).seg;
ClusterConfig_ptr out_p;
encode_ClusterConfig_ptr(seg, &out_p, new_cfg);
capn_setp(capn_root(&out_cap), 0, out_p.p);
free_ClusterConfig(new_cfg);
free(new_cfg);
new_cfg = NULL;
size_t out_len = capn_size(&out_cap);
uint8_t *out_bytes = (uint8_t *)malloc(out_len);
if (!out_bytes) {
capn_free(&out_cap);
send_upgrade_error(ep, req, c, "OOM re-encoding config");
return -ENOMEM;
}
capn_write_mem(&out_cap, out_bytes, out_len, 0);
capn_free(&out_cap);
SHA256(out_bytes, out_len, computed);
/* 5. Save to disk */
rc = conf_save_config(c->myconf, out_bytes, out_len, computed);
if (rc != 0) {
free(out_bytes);
send_upgrade_error(ep, req, c, "Failed to save new config to disk");
return rc;
}
/* 6. Update in-memory generation */
c->myconf->config_generation = new_gen;
/* 7. Push to standbys (best-effort; see push_config_to_standbys comment) */
int acked = push_config_to_standbys(c, out_bytes, out_len, computed,
c->myconf->config_version_tag);
free(out_bytes);
/* 8. ACK the admin tool */
upgrade_config_reply_t urep;
memset(&urep, 0, sizeof(urep));
urep.version_tag = c->myconf->config_version_tag;
urep.acked_count = (uint32_t)acked;
urep.error = NULL;
xce_reply_t reply;
init_reply_by_req(&reply, req);
reply.status = 0;
reply.data_which = RequestReply_data_upgradeconfigreplymsg;
reply.data.upgradeconfigreplymsg = &urep;
xce_reply(ep, c->myhost, &reply);
/* 9. Wait for in-flight checkpoint (up to 30 s), then signal restart */
struct timespec ckpt_start, ckpt_now;
clock_gettime(CLOCK_MONOTONIC, &ckpt_start);
while (atomic_load(&c->persist.checkpoint_in_progress)) {
usleep(10000);
clock_gettime(CLOCK_MONOTONIC, &ckpt_now);
if (ckpt_now.tv_sec - ckpt_start.tv_sec > 30) {
ERROR("Checkpoint did not complete within 30 s"
" -- restarting anyway");
break;
}
}
INFO("Config upgraded to tag=%016" PRIx64 " gen=%" PRIu64
" (acked=%d standbys) -- requesting restart",
c->myconf->config_version_tag, new_gen, acked);
atomic_store(&c->restart_requested, 1);
int stop_val = 1;
cbuf_put(&c->wbuf, &stop_val);
return 0;
}
#if CONF_ENABLE_UPGRADE_CONFIG
int handle_upgrade_config(cluster_t *c, endpoint_t *ep, xce_request_t *req,
const uint8_t *raw_pkt, size_t raw_pkt_sz)
{
uint8_t *in_bytes = NULL;
size_t in_len = 0;
uint8_t *in_sha = NULL;
int rc = xce_upgrade_config_req_extract_raw(raw_pkt, raw_pkt_sz,
&in_bytes, &in_len, &in_sha);
if (rc != 0 || !in_bytes || !in_sha) {
send_upgrade_error(ep, req, c,
"Failed to extract bytes from UpgradeConfigRequest");
free(in_bytes);
free(in_sha);
return rc != 0 ? rc : -EINVAL;
}
if (in_len == 0) {
free(in_bytes);
free(in_sha);
send_upgrade_error(ep, req, c, "bytes or sha256 field missing");
return -EINVAL;
}
rc = do_upgrade_config_with_bytes(c, ep, req, in_bytes, in_len, in_sha);
free(in_bytes);
free(in_sha);
return rc;
}
#else
int handle_upgrade_config(cluster_t *c, endpoint_t *ep, xce_request_t *req,
const uint8_t *raw_pkt, size_t raw_pkt_sz)
{
(void)c;
(void)raw_pkt;
(void)raw_pkt_sz;
xce_reply_t reply;
init_reply_by_req(&reply, req);
reply.status = -ENOSYS;
reply.data_which = RequestReply_data_nodata;
xce_reply(ep, c->myhost, &reply);
return -ENOSYS;
}
#endif
/* ── xce_probe_config_tag ───────────────────────────────────────────────────
*
* Single-RTT config tag probe to one peer controller over SSL.
*
* Wire format (same pattern as vote_request_thread in ha.c):
* Send: uint64_t size_hdr + capnp(ProbeConfigTagRequest) [direct struct]
* Receive: uint64_t size_hdr + capnp(ProbeConfigTagReply) [direct struct]
*
* Returns:
* 0 — success; *tag_out holds peer's config_tag (0 = no config)
* -ECONNREFUSED — peer refused the TCP connection (port not open)
* -ETIMEDOUT — connect poll timed out
* other negative errno — transient failure
*
* Requirements: 3.1, 1.3
* Boundary: Config Bootstrap (config_repl.c)
*/
int xce_probe_config_tag(const char *host, uint16_t port, uint64_t *tag_out)
{
if (!host || !tag_out)
return -EINVAL;
*tag_out = 0;
SSL *ssl = NULL;
int sock = -1;
int flags_saved = 0;
/* ── Step 1: SSL connect via connect_ssl_raw (same path as do_one_config_fetch) ── */
{
/* s_ssl_ctx is set in bootstrap_config_if_needed which passes it here.
* If NULL (unit test), fall back to plain TCP. */
SSL_CTX *ssl_ctx = s_probe_ssl_ctx;
if (ssl_ctx) {
int rc = connect_ssl_raw(ssl_ctx, host, port, 500, NULL, &ssl, &sock);
if (rc != 0)
return rc;
} else {
struct addrinfo hints, *res = NULL;
memset(&hints, 0, sizeof(hints));
hints.ai_family = AF_UNSPEC;
hints.ai_socktype = SOCK_STREAM;
char port_str[16];
snprintf(port_str, sizeof(port_str), "%u", (unsigned)port);
if (getaddrinfo(host, port_str, &hints, &res) != 0)
return -EHOSTUNREACH;
sock = socket(res->ai_family, res->ai_socktype, res->ai_protocol);
if (sock < 0) { int e = errno; freeaddrinfo(res); return -e; }
flags_saved = fcntl(sock, F_GETFL, 0);
fcntl(sock, F_SETFL, flags_saved | O_NONBLOCK);
connect(sock, res->ai_addr, res->ai_addrlen);
freeaddrinfo(res);
struct pollfd pfd = { .fd = sock, .events = POLLOUT | POLLERR | POLLHUP };
int pr;
do { pr = poll(&pfd, 1, 500); } while (pr < 0 && errno == EINTR);
if (pr == 0) { close(sock); return -ETIMEDOUT; }
if (pr < 0 || (pfd.revents & (POLLERR | POLLHUP))) { close(sock); return -ECONNREFUSED; }
int err = 0; socklen_t el = sizeof(err);
getsockopt(sock, SOL_SOCKET, SO_ERROR, &err, &el);
if (err) { close(sock); return -err; }
fcntl(sock, F_SETFL, flags_saved & ~O_NONBLOCK);
}
}
/* ── Step 2: Encode + send ProbeConfigTagRequest (direct struct) ── */
{
struct capn c;
struct capn_segment *cs;
struct ProbeConfigTagRequest req_s;
ProbeConfigTagRequest_ptr req_p;
uint8_t *buf = NULL;
int64_t blen = 0;
capn_init_malloc(&c);
cs = capn_root(&c).seg;
memset(&req_s, 0, sizeof(req_s));
req_s.name.str = ""; /* anonymous probe; peer logs remote addr */
req_s.name.len = 0;
req_p = new_ProbeConfigTagRequest(cs);
write_ProbeConfigTagRequest(&req_s, req_p);
capn_setp(capn_root(&c), 0, req_p.p);
blen = capn_size(&c);
if (blen > 0)
buf = (uint8_t *)malloc((size_t)blen);
if (!buf || capn_write_mem(&c, buf, (size_t)blen, 0) < 0) {
free(buf);
capn_free(&c);
close(sock);
return -EIO;
}
capn_free(&c);
/* Wire framing: 8-byte size prefix then capnp payload (matches ha.c pattern) */
uint64_t hdr = (uint64_t)blen;
ssize_t nsent;
nsent = (ssize_t)write(sock, &hdr, sizeof(hdr));
if (nsent == (ssize_t)sizeof(hdr))
nsent = (ssize_t)write(sock, buf, (size_t)blen);
free(buf);
if (nsent != (ssize_t)blen) {
close(sock);
return -EIO;
}
}
/* ── Step 3: Read + decode ProbeConfigTagReply (direct struct) ── */
{
uint64_t hdr = 0;
size_t off = 0;
/* Read 8-byte size header */
while (off < sizeof(hdr)) {
int n = (int)read(sock, (char *)&hdr + off, sizeof(hdr) - off);
if (n <= 0) {
close(sock);
return -EIO;
}
off += (size_t)n;
}
if (hdr == 0 || hdr > 65536) { /* sanity cap — reply is tiny */
close(sock);
return -EMSGSIZE;
}
uint8_t *buf = (uint8_t *)malloc((size_t)hdr);
if (!buf) {
close(sock);
return -ENOMEM;
}
off = 0;
while (off < (size_t)hdr) {
int n = (int)read(sock, buf + off, (size_t)hdr - off);
if (n <= 0) {
free(buf);
close(sock);
return -EIO;
}
off += (size_t)n;
}
struct capn c;
struct ProbeConfigTagReply rep_s;
ProbeConfigTagReply_ptr rep_p;
if (capn_init_mem(&c, buf, (size_t)hdr, 0) != 0) {
free(buf);
close(sock);
return -EPROTO;
}
rep_p.p = capn_getp(capn_root(&c), 0, 1);
read_ProbeConfigTagReply(&rep_s, rep_p);
capn_free(&c);
free(buf);
*tag_out = rep_s.configTag;
}
close(sock);
INFO("HA: probe config tag from %s:%u tag=%016" PRIx64,
host, (unsigned)port, *tag_out);
return 0;
}
#ifdef XCE_TESTING
/* Injection point for unit tests — NULL means use real xce_probe_config_tag */
int (*xce_probe_config_tag_hook)(const char *host, uint16_t port,
uint64_t *tag_out) = NULL;
#endif
/* ── bootstrap_config_if_needed ────────────────────────────────────────────
*
* Pre-election config probe for unconfigured nodes (config_version_tag == 0).
*
* Outcomes:
* 1. Local config exists (config_version_tag != 0) → return 0 immediately (3.1)
* 2. All reachable peers have tag=0 → first-boot cluster; return 0, no defer (3.3)
* 3. Any peer has tag > 0 → set ha.defer_config_fetch = true; return 0 (3.2)
* 4. No peer reachable → retry with exponential backoff 500ms→1s→...→10s (3.4)
*
* Requirements: 3.1, 3.2, 3.3, 3.4, 10.2
* Boundary: Config Bootstrap (config_repl.c)
*/
int bootstrap_config_if_needed(cluster_t *c)
{
/* Make the SSL context available to xce_probe_config_tag (used below) */
s_probe_ssl_ctx = c->ha.ssl_ctx;
/* Revised bootstrap strategy: skip the pre-election config probe entirely.
* The election protocol already carries config_tag in OP_requestVote, so
* the node with the freshest config wins naturally (Req 2.4 freshness gate).
* Standbys with config_tag=0 will lose the election (or yield to a fresher
* node), then fetch config from the elected primary via fetch_config_from_primary().
* This avoids the SSL/plain-TCP mismatch in the probe path. */
if (c->myconf->config_version_tag == 0) {
c->ha.defer_config_fetch = true;
INFO("HA bootstrap: config_tag=0 — skipping pre-election probe, "
"will fetch config from primary after election");
return 0;
}
/* Req 3.1: fast path — already have config */
if (c->myconf->config_version_tag != 0)
return 0;
const xce_cluster_config_t *pcfg = &c->myconf->peers_cfg;
int n_peers = pcfg->candidates_count;
/* Single-node or no peers configured — nothing to probe */
if (n_peers == 0) {
INFO("HA bootstrap: no peers configured, proceeding as first-boot primary");
return 0;
}
/* Exponential backoff state: 500ms → doubling → 10s cap (Req 3.4) */
uint32_t backoff_ms = 500;
const uint32_t backoff_max_ms = 10000;
int attempt = 0;
for (;;) {
int any_nonzero = 0; /* any peer replied with tag > 0 */
int any_reachable = 0; /* any peer replied at all (tag >= 0) */
for (int i = 0; i < n_peers; i++) {
const xce_candidate_t *peer = &pcfg->candidates[i];
uint64_t tag_out = 0;
#ifdef XCE_TESTING
int rc = xce_probe_config_tag_hook
? xce_probe_config_tag_hook(peer->hostname, (uint16_t)peer->port, &tag_out)
: xce_probe_config_tag(peer->hostname, (uint16_t)peer->port, &tag_out);
#else
int rc = xce_probe_config_tag(peer->hostname, (uint16_t)peer->port, &tag_out);
#endif
if (rc == 0) {
any_reachable = 1;
if (tag_out != 0) {
any_nonzero = 1;
/* Req 3.2: at least one peer has config — defer fetch */
c->ha.defer_config_fetch = true;
INFO("HA bootstrap: peer '%s:%u' has config tag=%016" PRIx64
" — deferring config fetch to post-election",
peer->hostname, (unsigned)peer->port, tag_out);
return 0;
}
}
}
if (any_reachable) {
/* Req 3.3: all reachable peers have tag=0 — first-boot cluster */
INFO("HA bootstrap: all reachable peers have tag=0 — first-boot cluster, "
"proceeding to election without config fetch");
return 0;
}
/* Req 3.4: no peer reachable — retry with exponential backoff */
attempt++;
WARN("HA bootstrap: no peer reachable after %d probe round(s) — "
"retrying in %u ms (attempt %d)",
attempt, backoff_ms, attempt);
usleep((useconds_t)backoff_ms * 1000);
backoff_ms = (backoff_ms * 2 < backoff_max_ms)
? backoff_ms * 2 : backoff_max_ms;
}
/* Unreachable — blocks until a peer responds or process is killed */
return 0;
}
/* ── sanitise_cn ────────────────────────────────── */
char *sanitise_cn(const char *src, size_t maxlen)
{
static char buf[128];
size_t n = maxlen < sizeof(buf) - 1 ? maxlen : sizeof(buf) - 1;
size_t i;
for (i = 0; i < n && src[i] != '\0'; i++)
buf[i] = (src[i] >= 0x20 && src[i] < 0x7f) ? src[i] : '?';
buf[i] = '\0';
return buf;
}
/* ── handle_ctrlhello ─────────────────────────────────────────────────────
*
* Primary-side handler for OP_hello from a joining standby (Req 6.5–6.7).
*
* Protocol:
* 1. Decode CtrlHelloRequest (applied_lsn, config_tag) from request body
* 2. repl_add_standby() + repl_start_catchup()
* 3. Reply CtrlHelloReply{committed_lsn, needs_snapshot, config_tag}
* 4. If needs_snapshot: persist_checkpoint() then WAL streaming must wait
* (snapshot transfer is out of scope for this task — stub logged)
* 5. Stream OP_walCatchupEntry [applied_lsn+1 → committed_lsn] from disk
* 6. On catch-up end: repl_complete_catchup()
* 7. If standby config_tag ≠ primary config_tag: push_config_to_standbys()
*
* Requirements: 6.5 (state sync), 6.6 (snapshot before WAL when needed),
* 6.7 (config push on mismatch)
*/
int handle_ctrlhello(cluster_t *c, endpoint_t *ep, xce_request_t *req)
{
/* 1. Extract CtrlHelloRequest fields */
if (req->body_which != Request_body_ctrlhellomsg || !req->body.ctrlhellomsg) {
WARN("handle_ctrlhello: malformed request (body_which=%d)", req->body_which);
return -EINVAL;
}
ctrl_hello_req_t *hello = req->body.ctrlhellomsg;
uint64_t standby_applied_lsn = hello->applied_lsn;
uint64_t standby_config_tag = hello->config_tag;
/* 2. Register standby in replication set and mark as catching up */
int rc = repl_add_standby(&c->persist.repl, ep,
hello->name ? hello->name : "unknown", 0);
if (rc < 0 && rc != -ENOSPC) {
WARN("handle_ctrlhello: repl_add_standby failed: %d", rc);
/* Still proceed — standby may already be registered */
}
repl_start_catchup(&c->persist.repl, ep, standby_applied_lsn);
/* Determine primary's committed LSN and snapshot need */
uint64_t committed_lsn = atomic_load_explicit(&c->persist.committed_lsn,
memory_order_acquire);
int needs_snap = repl_needs_snapshot(&c->persist.repl,
standby_applied_lsn,
c->persist.checkpoint_lsn);
/* 3. Send CtrlHelloReply */
ctrl_hello_reply_t hrep = {
.committed_lsn = committed_lsn,
.needs_snapshot = needs_snap,
.config_tag = c->myconf->config_version_tag,
};
xce_reply_t reply;
init_reply_by_req(&reply, req);
reply.status = 0;
reply.data_which = RequestReply_data_ctrlhelloreplymsg;
reply.data.ctrlhelloreplymsg = &hrep;
xce_reply(ep, c->myhost, &reply);
/* 4. Snapshot transfer (Req 6.6) — stub: log and skip.
* Full snapshot transfer (OP_snapshotTransfer) requires persist_checkpoint()
* + raw blob transfer; deferred to a follow-on task. */
if (needs_snap) {
WARN("handle_ctrlhello: standby %s needs snapshot (applied_lsn=%lu) — "
"snapshot transfer not yet implemented; standby must reconnect after "
"primary checkpoint",
hello->name ? hello->name : "?",
(unsigned long)standby_applied_lsn);
repl_complete_catchup(&c->persist.repl, ep);
return 0;
}
/* 5. Stream OP_walCatchupEntry [applied_lsn+1 → committed_lsn].
*
* Walk WAL segment files on disk in LSN order, read each wal_entry_hdr_t,
* send entries in [standby_applied_lsn+1, committed_lsn] as raw capnp
* requests. We re-use the existing WAL segment scan pattern from
* persist_truncate_wal_above().
*
* For now, send WalCatchupEntry payloads as opaque Data blobs using the
* existing xce_request() send path. A standby that receives
* OPCode_walCatchupEntry applies it via apply_wal_entry() and replies
* OPCode_walAck.
*/
if (committed_lsn > standby_applied_lsn) {
/* Collect and sort WAL segments */
uint64_t seg_lsns[4096];
int nseg = 0;
DIR *d = opendir(c->persist.wal_path);
if (d) {
struct dirent *e;
while ((e = readdir(d)) != NULL &&
nseg < (int)(sizeof(seg_lsns) / sizeof(seg_lsns[0]))) {
if (strncmp(e->d_name, "seg-", 4) != 0) continue;
uint64_t sl = 0;
if (sscanf(e->d_name, "seg-%" SCNx64 ".wal", &sl) != 1) continue;
seg_lsns[nseg++] = sl;
}
closedir(d);
}
/* Insertion sort ascending */
for (int i = 1; i < nseg; i++) {
uint64_t key = seg_lsns[i];
int j = i - 1;
while (j >= 0 && seg_lsns[j] > key) { seg_lsns[j+1] = seg_lsns[j]; j--; }
seg_lsns[j+1] = key;
}
/* Stream entries in each segment that falls in [applied+1, committed] */
for (int si = 0; si < nseg; si++) {
/* Skip segments that start after committed_lsn */
if (si + 1 < nseg && seg_lsns[si + 1] <= standby_applied_lsn)
continue; /* whole segment is below the standby's watermark */
if (seg_lsns[si] > committed_lsn)
break; /* past our range */
char seg_path[4096];
snprintf(seg_path, sizeof(seg_path),
"%s/seg-%016" PRIx64 ".wal", c->persist.wal_path, seg_lsns[si]);
int fd = open(seg_path, O_RDONLY);
if (fd < 0) continue;
uint32_t off = 0;
for (;;) {
wal_entry_hdr_t hdr;
ssize_t n = pread(fd, &hdr, sizeof(hdr), (off_t)off);
if (n < (ssize_t)sizeof(hdr)) break;
if (hdr.lsn == 0 && hdr.type == 0 && hdr.payload_len == 0) break;
if (hdr.lsn > committed_lsn) break;
if (hdr.lsn > standby_applied_lsn) {
/* Stream WAL entry as OPCode_walCatchupEntry.
* Encoded via the raw capnp path: set opcode + seq,
* body carries the WalCatchupEntry struct. */
xce_request_t stream_req;
memset(&stream_req, 0, sizeof(stream_req));
stream_req.opcode = OPCode_walCatchupEntry;
stream_req.body_which = Request_body_nomsg;
wal_catchup_entry_t entry = {
.lsn = hdr.lsn,
.entry_type = (uint8_t)hdr.type,
.payload = NULL,
};
if (hdr.payload_len > 0) {
uint8_t *pbuf = malloc(hdr.payload_len);
if (pbuf) {
ssize_t pr = pread(fd, pbuf, hdr.payload_len,
(off_t)(off + sizeof(hdr)));
if (pr == (ssize_t)hdr.payload_len) {
entry.payload = (xce_data_t *)pbuf;
} else {
free(pbuf);
off += (uint32_t)(sizeof(hdr) + hdr.payload_len);
continue;
}
}
}
/* Store in void* slot; decode_xce_request handles via opcode */
stream_req.body.walcatchupentrymsg = &entry;
xce_request(ep, &stream_req);
free(entry.payload);
}
off += (uint32_t)(sizeof(hdr) + hdr.payload_len);
}
close(fd);
}
}
/* 6. Catch-up complete */
repl_complete_catchup(&c->persist.repl, ep);
INFO("handle_ctrlhello: standby %s catch-up complete "
"(applied_lsn=%lu → committed_lsn=%lu)",
hello->name ? hello->name : "?",
(unsigned long)standby_applied_lsn,
(unsigned long)committed_lsn);
/* 7. Config push if standby is stale (Req 6.7) */
if (standby_config_tag != c->myconf->config_version_tag) {
INFO("handle_ctrlhello: pushing config to standby %s "
"(standby_tag=%lu, primary_tag=%lu)",
hello->name ? hello->name : "?",
(unsigned long)standby_config_tag,
(unsigned long)c->myconf->config_version_tag);
/* push_config_to_standbys() is best-effort; ignore return for now */
(void)push_config_to_standbys(c, NULL, 0, NULL,
c->myconf->config_version_tag);
}
return 0;
}