Add pub library and daemon

1 files changed, 964 insertions, 0 deletions

diff --git a/src/pub/skabus-pubd.c b/src/pub/skabus-pubd.c
new file mode 100644
index 0000000..99a6ddf
--- /dev/null
+++ b/src/pub/skabus-pubd.c
@@ -0,0 +1,964 @@
+/* ISC license. */
+
+#include <stdint.h>
+#include <unistd.h>
+#include <sys/stat.h>
+#include <sys/uio.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <signal.h>
+#include <stdlib.h>
+#include <regex.h>
+
+#include <skalibs/posixishard.h>
+#include <skalibs/uint32.h>
+#include <skalibs/uint64.h>
+#include <skalibs/types.h>
+#include <skalibs/allreadwrite.h>
+#include <skalibs/bytestr.h>
+#include <skalibs/sgetopt.h>
+#include <skalibs/env.h>
+#include <skalibs/error.h>
+#include <skalibs/strerr2.h>
+#include <skalibs/stralloc.h>
+#include <skalibs/tai.h>
+#include <skalibs/djbunix.h>
+#include <skalibs/sig.h>
+#include <skalibs/iopause.h>
+#include <skalibs/selfpipe.h>
+#include <skalibs/cdb.h>
+#include <skalibs/webipc.h>
+#include <skalibs/genset.h>
+#include <skalibs/avltree.h>
+#include <skalibs/avltreen.h>
+#include <skalibs/unixmessage.h>
+#include <skalibs/unixconnection.h>
+#include <skalibs/skaclient.h>
+
+#include <s6/accessrules.h>
+
+#include <skabus/pub.h>
+
+#define USAGE "skabus-pubd [ -v verbosity ] [ -1 ] [ -c maxconn ] [ -t timeout ] [ -T lameducktimeout ] [ -i rulesdir | -x rulesfile ] [ -S | -s ] [ -k controlre ] msgfsdir"
+#define dieusage() strerr_dieusage(100, USAGE) ;
+#define dienomem() strerr_diefu1sys(111, "stralloc_catb") ;
+#define die() strerr_dief1sys(101, "unexpected error") ;
+
+#define MSGINFO_PACK(n) (11 + TAIN_PACK + (n))
+
+static unsigned int verbosity = 1 ;
+static int cont = 1 ;
+static uint64_t serial = 1 ;
+static tain_t answertto = TAIN_INFINITE_RELATIVE ;
+static tain_t lameduckdeadline = TAIN_INFINITE_RELATIVE ;
+static int flagidstrpub = 0 ;
+
+static unsigned int rulestype = 0 ;
+static char const *rules = 0 ;
+static int cdbfd = -1 ;
+static struct cdb cdbmap = CDB_ZERO ;
+
+static char const *msgfsdir ;
+
+static void handle_signals (void)
+{
+  for (;;) switch (selfpipe_read())
+  {
+    case -1 : strerr_diefu1sys(111, "selfpipe_read()") ;
+    case 0 : return ;
+    case SIGTERM :
+    {
+      if (cont)
+      {
+        cont = 0 ;
+        tain_add_g(&lameduckdeadline, &lameduckdeadline) ;
+      }
+      break ;
+    }
+    case SIGHUP :
+    {
+      int fd ;
+      struct cdb c = CDB_ZERO ;
+      if (rulestype != 2) break ;
+      fd = open_readb(rules) ;
+      if (fd < 0) break ;
+      if (cdb_init(&c, fd) < 0)
+      {
+        fd_close(fd) ;
+        break ;
+      }
+      cdb_free(&cdbmap) ;
+      fd_close(cdbfd) ;
+      cdbfd = fd ;
+      cdbmap = c ;
+    }
+    break ;
+    default : break ;
+  }
+}
+
+static void *uint32_dtok (uint32_t d, void *x)
+{
+  (void)x ;
+  return (void *)(uintptr_t)d ;
+}
+
+static int ptr_cmp (void const *a, void const *b, void *x)
+{
+  (void)x ;
+  return a < b ? -1 : a > b ;
+}
+
+
+ /* fd reference counter */
+
+typedef struct fdcount_s fdcount_t, *fdcount_t_ref ;
+struct fdcount_s
+{
+  int fd ;
+  uint32_t n ;
+} ;
+
+static void *fdcount_dtok (uint32_t d, void *x)
+{
+  return &GENSETDYN_P(fdcount_t, (gensetdyn *)x, d)->fd ;
+}
+
+static int fd_cmp (void const *a, void const *b, void *x)
+{
+  int fda = *(int *)a ;
+  int fdb = *(int *)b ;
+  (void)x ;
+  return fda < fdb ? -1 : fda > fdb ;
+}
+
+static gensetdyn fdcountblob = GENSETDYN_INIT(fdcount_t, 3, 3, 8) ;
+static avltree fdcountmap = AVLTREE_INIT(3, 3, 8, &fdcount_dtok, &fd_cmp, &fdcountblob) ;
+#define FDCOUNT(i) GENSETDYN_P(fdcount_t, &fdcountblob, (i))
+
+static inline fdcount_t *fdcount_search (int fd)
+{
+  uint32_t d ;
+  fdcount_t *p ;
+  if (avltree_search(&fdcountmap, &fd, &d)) return FDCOUNT(d) ;
+  if (!gensetdyn_new(&fdcountblob, &d)) dienomem() ;
+  p = FDCOUNT(d) ;
+  p->fd = fd ;
+  p->n = 0 ;
+  if (!avltree_insert(&fdcountmap, d)) dienomem() ;
+  return p ;
+}
+
+static void fdcount_closecb (int fd, void *p)
+{
+  uint32_t d ;
+  avltree_search(&fdcountmap, &fd, &d) ;
+  if (!--FDCOUNT(d)->n) fd_close(fd) ;
+}
+
+
+ /* client */
+
+typedef struct client_s client_t, *client_t_ref ;
+struct client_s
+{
+  uint32_t next ;
+  uint32_t xindexsync ;
+  uint32_t xindexasync ;
+  tain_t deadline ;
+  regex_t idstr_re ;
+  regex_t subscribe_re ;
+  regex_t write_re ;
+  avltree subscribers ;
+  unixmessage_sender_t asyncout ;
+  unixconnection_t sync ;
+  char idstr[SKABUS_PUB_IDSTR_SIZE + 1] ;
+} ;
+
+static genset *clients ;
+static unsigned int sentinel ;
+static avltreen *clientmap ;
+#define CLIENT(i) genset_p(client_t, clients, (i))
+#define numconn (genset_n(clients) - 1)
+
+static inline void client_free (client_t *c)
+{
+  fd_close(unixmessage_sender_fd(&c->sync.out)) ;
+  if (unixmessage_sender_fd(&c->asyncout) >= 0)
+    fd_close(unixmessage_sender_fd(&c->asyncout)) ;
+  unixconnection_free(&c->sync) ;
+  unixmessage_sender_free(&c->asyncout) ;
+  if (c->idstr[0])
+  {
+    regfree(&c->subscribe_re) ;
+    regfree(&c->write_re) ;
+  }
+  else regfree(&c->idstr_re) ;
+  avltree_free(&c->subscribers) ;
+}
+
+static void *idstr_dtok (uint32_t d, void *x)
+{
+  (void)x ;
+  return CLIENT(d)->idstr ;
+}
+
+static int idstr_cmp (void const *a, void const *b, void *x)
+{
+  (void)x ;
+  return strcmp((char const *)a, (char const *)b) ;
+}
+
+static inline void client_delete (uint32_t cc, uint32_t prev)
+{
+  client_t *c = CLIENT(cc) ;
+  uint32_t i = CLIENT(sentinel)->next ;
+  while (i != sentinel)
+  {
+    client_t *p = CLIENT(i) ;
+    avltree_delete(&p->subscribers, (void const *)(uintptr_t)cc) ;
+    i = p->next ;
+  }
+  CLIENT(prev)->next = c->next ;
+  if (c->idstr[0]) avltreen_delete(clientmap, c->idstr) ;
+  client_free(c) ;
+  genset_delete(clients, cc) ;
+}
+
+static void remove (uint32_t *i, uint32_t j)
+{
+  client_delete(*i, j) ;
+  *i = j ;
+}
+
+static void client_setdeadline (client_t *c)
+{
+  tain_t blah ;
+  tain_half(&blah, &tain_infinite_relative) ;
+  tain_add_g(&blah, &blah) ;
+  if (tain_less(&blah, &c->deadline))
+    tain_add_g(&c->deadline, &answertto) ;
+}
+
+static inline int client_prepare_iopause (uint32_t i, tain_t *deadline, iopause_fd *x, uint32_t *j)
+{
+  client_t *c = CLIENT(i) ;
+  if (tain_less(&c->deadline, deadline)) *deadline = c->deadline ;
+  if (!unixmessage_sender_isempty(&c->sync.out) || !unixmessage_receiver_isempty(&c->sync.in) || (cont && !unixmessage_receiver_isfull(&c->sync.in)))
+  {
+    x[*j].fd = unixmessage_sender_fd(&c->sync.out) ;
+    x[*j].events = (!unixmessage_receiver_isempty(&c->sync.in) || (cont && !unixmessage_receiver_isfull(&c->sync.in)) ? IOPAUSE_READ : 0) | (!unixmessage_sender_isempty(&c->sync.out) ? IOPAUSE_WRITE : 0) ;
+    c->xindexsync = (*j)++ ;
+  }
+  else c->xindexsync = 0 ;
+  if (!unixmessage_sender_isempty(&c->asyncout))
+  {
+    x[*j].fd = unixmessage_sender_fd(&c->asyncout) ;
+    x[*j].events = IOPAUSE_WRITE ;
+    c->xindexasync = (*j)++ ;
+  }
+  else c->xindexasync = 0 ;
+  return c->xindexsync || c->xindexasync ;
+}
+
+static inline void client_add (int fd, regex_t const *idstr_re, unsigned int flags)
+{
+  uint32_t i = genset_new(clients) ;
+  client_t *c = CLIENT(i) ;
+  unixconnection_init(&c->sync, fd, fd) ;
+  unixmessage_sender_init_withclosecb(&c->asyncout, -(int)flags - 1, &fdcount_closecb, 0) ;
+  c->idstr[0] = 0 ;
+  c->idstr_re = *idstr_re ;
+  avltree_init(&c->subscribers, 3, 3, 8, &uint32_dtok, &ptr_cmp, 0) ;
+  tain_add_g(&c->deadline, &answertto) ;
+  c->next = CLIENT(sentinel)->next ;
+  CLIENT(sentinel)->next = i ;
+}
+
+static int enqueue_message (uint32_t dd, unixmessage_t const *m)
+{
+  client_t *d = CLIENT(dd) ;
+  if (!unixmessage_put_and_close(&d->asyncout, m, unixmessage_bits_closeall)) return 0 ;
+  client_setdeadline(d) ;
+  for (unsigned int i = 0 ; i < m->nfds ; i++)
+    fdcount_search(m->fds[i])->n++ ;
+  return 1 ;
+}
+
+static int unsendmessage_iter (uint32_t dd, unsigned int h, void *data)
+{
+  unixmessage_unput(&CLIENT(dd)->asyncout) ;
+  (void)h ;
+  (void)data ;
+  return 1 ;
+}
+
+static int sendmessage_iter (uint32_t dd, unsigned int h, void *data)
+{
+  (void)h ;
+  return enqueue_message(dd, (unixmessage_t *)data) ;
+}
+
+static int store_text (char const *s, size_t len)
+{
+  int fd ;
+  size_t msgfsdirlen = strlen(msgfsdir) ;
+  char fn[msgfsdirlen + TAIN_PACK + 10] ;
+  fn[0] = '@' ;
+  memcpy(fn + 1, msgfsdir, msgfsdirlen) ;
+  fn[1 + msgfsdirlen] = '/' ;
+  tain_pack(fn + msgfsdirlen + 2, &STAMP) ;
+  memcpy(fn + msgfsdirlen + 2 + TAIN_PACK, ":XXXXXX", 8) ;
+  fd = mkstemp(fn) ;
+  if (fd < 0) return fd ;
+  if (!writenclose_unsafe(fd, s, len))
+  {
+    fd_close(fd) ;
+    return -1 ;
+  }
+  fd_close(fd) ;
+  fd = open(fn, O_RDONLY) ;  /* too bad you can't just lose writing rights */
+  unlink_void(fn) ;  /* still there as long as fd is open */
+  return fd ;
+}
+
+static void fill_msginfo (char *pack, char const *idstr, size_t idlen, uint8_t flags)
+{
+  uint64_pack_big(pack, serial++) ;
+  tain_pack(pack + 8, &STAMP) ;
+  pack[8 + TAIN_PACK] = flags ;
+  pack[9 + TAIN_PACK] = idlen ;
+  memcpy(pack + 10 + TAIN_PACK, idstr, idlen + 1) ;
+}
+
+static int announce (char const *what, size_t whatlen, char const *idstr)
+{
+  size_t idlen = strlen(idstr) ;
+  int fd ;
+  char s[MSGINFO_PACK(idlen)] ;
+  unixmessage_t m = { .s = s, .len = MSGINFO_PACK(idlen), .fds = &fd, .nfds = 1 } ;
+  if (!*idstr) return 1 ;
+  fill_msginfo(s, idstr, idlen, 0) ;
+  fd = store_text(what, whatlen) ;
+  if (fd < 0) return 0 ;
+  if (!avltree_iter_withcancel(&CLIENT(sentinel)->subscribers, &sendmessage_iter, &unsendmessage_iter, &m)) return 0 ;
+  return 1 ;
+}
+
+static inline int client_flush (uint32_t i, iopause_fd const *x)
+{
+  client_t *c = CLIENT(i) ;
+  int isflushed = 2 ;
+  if (c->xindexsync && (x[c->xindexsync].revents & IOPAUSE_WRITE))
+  {
+    if (!unixmessage_sender_flush(&c->sync.out))
+      if (error_isagain(errno)) isflushed = 0 ;
+      else
+      {
+        char what[2] = "-" ;
+        what[1] = errno ;
+        if (verbosity) strerr_warnwu2sys("unixmessage_sender_flush ", c->idstr) ;
+        if (!announce(what, 2, c->idstr)) dienomem() ;
+        return 0 ;
+      }
+    else isflushed = 1 ;
+  }
+
+  if (c->xindexasync && (x[c->xindexasync].revents & IOPAUSE_WRITE))
+  {
+    if (!unixmessage_sender_flush(&c->asyncout))
+      if (error_isagain(errno)) isflushed = 0 ;
+      else
+      {
+        char what[2] = "-" ;
+        what[1] = errno ;
+        if (verbosity) strerr_warnwu2sys("unixmessage_sender_flush ", c->idstr) ;
+        if (!announce(what, 2, c->idstr)) dienomem() ;
+        return 0 ;
+      }
+    else isflushed = !!isflushed ;
+  }
+
+  if (isflushed == 1) tain_add_g(&c->deadline, &tain_infinite_relative) ;
+  return 1 ;
+}
+
+static int answer (client_t *c, char e)
+{
+  unixmessage_t m = { .s = &e, .len = 1, .fds = 0, .nfds = 0 } ;
+  if (!unixmessage_put(&c->sync.out, &m)) return 0 ;
+  client_setdeadline(c) ;
+  return 1 ;
+}
+
+static int do_register (uint32_t cc, unixmessage_t const *m)
+{
+  uint32_t srelen, wrelen, dummy ;
+  client_t *c = CLIENT(cc) ;
+  char const *s = m->s ;
+  size_t len = m->len ;
+  int r ;
+  size_t idlen ;
+  if (len < 12 || m->nfds) return (errno = EPROTO, 0) ;
+  idlen = (unsigned char)*s++ ; len-- ;
+  uint32_unpack_big(s, &srelen) ; s += 4 ; len -= 4 ;
+  uint32_unpack_big(s, &wrelen) ; s += 4 ; len -= 4 ;
+  if (len != idlen + srelen + wrelen + 3 || s[idlen] || s[idlen + srelen + 1] || s[idlen + srelen + wrelen + 2] || !idlen || !s[idlen-1]) return (errno = EPROTO, 0) ;
+  if (idlen > SKABUS_PUB_IDSTR_SIZE) return answer(c, ENAMETOOLONG) ;
+  if (c->idstr[0]) return answer(c, EISCONN) ;
+  if (regexec(&c->idstr_re, s, 0, 0, 0)) return answer(c, EPERM) ;
+  if (avltreen_search(clientmap, s, &dummy)) return answer(c, EBUSY) ;
+  r = regcomp(&c->subscribe_re, s + idlen + 1, REG_EXTENDED | REG_NOSUB) ;
+  if (r) return answer(c, r == REG_ESPACE ? ENOMEM : EINVAL) ;
+  r = regcomp(&c->write_re, s + idlen + srelen + 2, REG_EXTENDED | REG_NOSUB) ;
+  if (r)
+  {
+    regfree(&c->subscribe_re) ;
+    return answer(c, r == REG_ESPACE ? ENOMEM : EINVAL) ;
+  }
+  memcpy(c->idstr, s, idlen+1) ;
+  avltreen_insert(clientmap, cc) ;
+  if (!announce("+", 1, s))
+  {
+    char e = errno ;
+    regfree(&c->write_re) ;
+    regfree(&c->subscribe_re) ;
+    avltreen_delete(clientmap, c->idstr) ;
+    return answer(c, e) ;
+  }
+  regfree(&c->idstr_re) ;
+  return answer(c, 0) ;
+}
+
+static int do_list (uint32_t cc, unixmessage_t const *m)
+{
+  client_t *c = CLIENT(cc) ;
+  uint32_t dd = CLIENT(sentinel)->next ;
+  if (m->len || m->nfds) return (errno = EPROTO, 0) ;
+  unsigned int n = avltreen_len(clientmap) - 1 ;
+  {
+    char pack[9] = "" ;
+    char lens[n] ;
+    struct iovec v[1+(n<<1)] ;
+    unixmessage_v_t mreply = { .v = v, .vlen = 1+(n<<1), .fds = 0, .nfds = 0 } ;
+    unsigned int registered = 0 ;
+    v[0].iov_base = pack ; v[0].iov_len = 9 ;
+    for (unsigned int i = 0 ; i < n ; i++)
+    {
+      client_t *d = CLIENT(dd) ;
+      if (d->idstr[0])
+      {
+        size_t len = strlen(d->idstr) ;
+        lens[i] = (unsigned char)len ;
+        v[1+(i<<1)].iov_base = lens + i ;
+        v[1+(i<<1)].iov_len = 1 ;
+        v[2+(i<<1)].iov_base = d->idstr ;
+        v[2+(i<<1)].iov_len = len+1 ;
+        registered++ ;
+      }
+      dd = d->next ;
+    }
+    uint32_pack_big(pack+1, registered) ;
+    uint32_pack_big(pack+5, n - registered) ;
+    if (!unixmessage_putv(&c->sync.out, &mreply)) return answer(c, errno) ;
+  }
+  client_setdeadline(c) ;
+  return 1 ;
+}
+
+static int do_unsubscribe (uint32_t cc, unixmessage_t const *m)
+{
+  uint32_t dd ;
+  char const *s = m->s ;
+  size_t len = m->len ;
+  client_t *c = CLIENT(cc) ;
+  if (!len-- || m->nfds) return (errno = EPROTO, 0) ;
+  if (len != (unsigned int)(unsigned char)s[0] + 1 || s[len]) return (errno = EPROTO, 0) ;
+  s++ ;
+  if (!c->idstr[0]) return answer(c, EPERM) ;
+  if (!avltreen_search(clientmap, s, &dd)) return answer(c, errno) ;
+  if (!avltree_delete(&CLIENT(dd)->subscribers, (void const *)(uintptr_t)cc)) return answer(c, errno) ;
+  return answer(c, 0) ;
+}
+
+static int do_subscribe (uint32_t cc, unixmessage_t const *m)
+{
+  client_t *c = CLIENT(cc) ;
+  char const *s = m->s ;
+  size_t len = m->len ;
+  client_t *d ;
+  uint32_t dd, dummy ;
+  if (!len-- || m->nfds) return (errno = EPROTO, 0) ;
+  if (len != (unsigned int)(unsigned char)s[0] + 1 || s[len]) return (errno = EPROTO, 0) ;
+  s++ ;
+  if (!c->idstr[0]) return answer(c, EPERM) ;
+  if (!avltreen_search(clientmap, s, &dd)) return answer(c, errno) ;
+  d = CLIENT(dd) ;
+  if (regexec(&d->subscribe_re, c->idstr, 0, 0, 0)) return answer(c, EPERM) ;
+  if (!avltree_search(&d->subscribers, c->idstr, &dummy))
+  {
+    if (!avltree_insert(&d->subscribers, cc)) return answer(c, errno) ;
+  }
+  return answer(c, 0) ;
+}
+
+static int do_sendpm (uint32_t cc, unixmessage_t const *m)
+{
+  client_t *c = CLIENT(cc) ;
+  char const *s = m->s ;
+  size_t len = m->len ;
+  size_t idlen ;
+  uint32_t dd ;
+  client_t *d ;
+  if (len < 2) return (errno = EPROTO, 0) ;
+  idlen = (unsigned char)s[0] ; s++ ; len-- ;
+  if (len < idlen + 1 || s[idlen]) return (errno = EPROTO, 0) ;
+  if (idlen > SKABUS_PUB_IDSTR_SIZE)
+  {
+    unixmessage_drop(m) ;
+    return answer(c, ENAMETOOLONG) ;
+  }
+  if (m->nfds > UNIXMESSAGE_MAXFDS - 1)
+  {
+    unixmessage_drop(m) ;
+    return answer(c, ENFILE) ;
+  }
+  if (!c->idstr[0])
+  {
+    unixmessage_drop(m) ;
+    return answer(c, EPERM) ;
+  }
+  if (!avltreen_search(clientmap, s, &dd))
+  {
+    unixmessage_drop(m) ;
+    return answer(c, errno) ;
+  }
+  s += idlen+1 ; len -= idlen+1 ;
+  d = CLIENT(dd) ;
+  if (regexec(&d->write_re, c->idstr, 0, 0, 0))
+  {
+    unixmessage_drop(m) ;
+    return answer(c, EPERM) ;
+  }
+
+  {
+    size_t cidlen = strlen(c->idstr) ;
+    char pack[1 + MSGINFO_PACK(cidlen)] ;
+    int fds[1 + m->nfds] ;
+    unixmessage_t mtosend = { .s = pack + 1, .len = MSGINFO_PACK(cidlen), .fds = fds, .nfds = 1 + m->nfds } ;
+    fds[0] = store_text(s, len) ;
+    if (fds[0] < 0)
+    {
+      unixmessage_drop(m) ;
+      return answer(c, errno) ;
+    }
+    fill_msginfo(pack + 1, c->idstr, cidlen, 1) ;
+    for (unsigned int i = 0 ; i < m->nfds ; i++) fds[1+i] = m->fds[i] ;
+    if (!unixmessage_put_and_close(&d->asyncout, &mtosend, unixmessage_bits_closeall))
+    {
+      unixmessage_drop(m) ;
+      return answer(c, errno) ;
+    }
+    client_setdeadline(d) ;
+    pack[0] = 0 ;
+    mtosend.s = pack ;
+    mtosend.len = 9 ;
+    mtosend.fds = 0 ;
+    mtosend.nfds = 0 ;
+    return enqueue_message(cc, &mtosend) ;
+  }
+}
+
+static int do_send (uint32_t cc, unixmessage_t const *m)
+{
+  client_t *c = CLIENT(cc) ;
+  size_t cidlen = strlen(c->idstr) ;
+  if (m->nfds > UNIXMESSAGE_MAXFDS - 1)
+  {
+    unixmessage_drop(m) ;
+    return answer(c, ENFILE) ;
+  }
+  {
+    char pack[1 + MSGINFO_PACK(cidlen)] ;
+    int fds[1 + m->nfds] ;
+    unixmessage_t mtosend = { .s = pack + 1, .len = MSGINFO_PACK(cidlen), .fds = fds, .nfds = 1 + m->nfds } ;
+    fds[0] = store_text(m->s, m->len) ;
+    if (fds[0] < 0)
+    {
+      unixmessage_drop(m) ;
+      return answer(c, errno) ;
+    }
+    fill_msginfo(pack + 1, c->idstr, cidlen, 0) ;
+    for (unsigned int i = 0 ; i < m->nfds ; i++) fds[1+i] = m->fds[i] ;
+    if (!avltree_iter_withcancel(&c->subscribers, &sendmessage_iter, &unsendmessage_iter, &mtosend))
+    {
+      unixmessage_drop(m) ;
+      return answer(c, errno) ;
+    }
+    pack[0] = 0 ;
+    mtosend.s = pack ;
+    mtosend.len = 9 ;
+    mtosend.fds = 0 ;
+    mtosend.nfds = 0 ;
+    return enqueue_message(cc, &mtosend) ;
+  }
+}
+
+static int do_error (uint32_t cc, unixmessage_t const *m)
+{
+  (void)cc ;
+  (void)m ;
+  return (errno = EPROTO, 0) ;
+}
+
+typedef int parsefunc_t (uint32_t, unixmessage_t const *) ;
+typedef parsefunc_t *parsefunc_t_ref ;
+
+static inline int parse_protocol (unixmessage_t const *m, void *p)
+{
+  static parsefunc_t_ref const f[7] =
+  {
+    &do_send,
+    &do_sendpm,
+    &do_subscribe,
+    &do_unsubscribe,
+    &do_list,
+    &do_register,
+    &do_error
+  } ;
+  unixmessage_t mcopy = { .s = m->s + 1, .len = m->len - 1, .fds = m->fds, .nfds = m->nfds } ;
+  if (!m->len)
+  {
+    unixmessage_drop(m) ;
+    return (errno = EPROTO, 0) ;
+  }
+  if (!(*f[byte_chr("!+SULR", 6, m->s[0])])(*(uint32_t *)p, &mcopy))
+  {
+    unixmessage_drop(m) ;
+    return 0 ;
+  }
+  return 1 ;
+}
+
+static inline int client_read (uint32_t cc, iopause_fd const *x)
+{
+  client_t *c = CLIENT(cc) ;
+  if (!unixmessage_receiver_isempty(&c->sync.in) || (c->xindexsync && (x[c->xindexsync].revents & IOPAUSE_READ)))
+  {
+    if (unixmessage_sender_fd(&c->asyncout) < 0)
+    {
+      unixmessage_t m ;
+      int r = unixmessage_receive(&c->sync.in, &m) ;
+      if (r < 0) return -1 ;
+      if (r)
+      {
+        unsigned int flags = -(unixmessage_sender_fd(&c->asyncout) + 1) ;
+        if (!skaclient_server_ack(&m, &c->sync.out, &c->asyncout, SKABUS_PUB_BANNER1, SKABUS_PUB_BANNER1_LEN, SKABUS_PUB_BANNER2, SKABUS_PUB_BANNER2_LEN))
+        {
+          unixmessage_drop(&m) ;
+          return -1 ;
+        }
+        if (!(flags & 1)) unixmessage_receiver_refuse_fds(&c->sync.in) ;
+      }
+    }
+    else
+    {
+      int r = unixmessage_handle(&c->sync.in, &parse_protocol, &cc) ;
+      if (r <= 0) return r ;
+    }
+  }
+  return 1 ;
+}
+
+
+ /* Environment on new connections */
+
+static int makere (regex_t *re, char const *s, char const *var)
+{
+  size_t varlen = strlen(var) ;
+  if (str_start(s, var) && (s[varlen] == '='))
+  {
+    int r = regcomp(re, s + varlen + 1, REG_EXTENDED | REG_NOSUB) ;
+    if (r)
+    {
+      if (verbosity)
+      {
+        char buf[256] ;
+        regerror(r, re, buf, 256) ;
+        strerr_warnw6x("invalid ", var, " value: ", s + varlen + 1, ": ", buf) ;
+      }
+      return -1 ;
+    }
+    else return 1 ;
+  }
+  return 0 ;
+}
+
+static void defaultre (regex_t *re, int flag)
+{
+  char const *s = flag ? ".*" : "^$" ;
+  int r = regcomp(re, s, REG_EXTENDED | REG_NOSUB) ;
+  if (r)
+  {
+    char buf[256] ;
+    regerror(r, re, buf, 256) ;
+    strerr_diefu4x(100, "compile ", s, " into a regular expression: ", buf) ;
+  }
+}
+
+static inline int parse_env (char const *const *envp, regex_t *idstr_re, unsigned int *flags)
+{
+  unsigned int fl = 0 ;
+  int idstr_done = 0 ;
+  for (; *envp ; envp++)
+  {
+    if (str_start(*envp, "SKABUS_PUB_SENDFDS=")) fl |= 1 ;
+    if (!idstr_done)
+    {
+      idstr_done = makere(idstr_re, *envp, "SKABUS_PUB_ID_REGEX") ;
+      if (idstr_done < 0) return 0 ;
+    }
+    if (idstr_done) return 1 ;
+  }
+  if (!idstr_done) defaultre(idstr_re, flagidstrpub) ;
+  *flags = fl ;
+  return 1 ;
+}
+
+static inline int new_connection (int fd, regex_t *idstr_re, unsigned int *flags)
+{
+  s6_accessrules_params_t params = S6_ACCESSRULES_PARAMS_ZERO ;
+  s6_accessrules_result_t result = S6_ACCESSRULES_ERROR ;
+  uid_t uid ;
+  gid_t gid ;
+
+  if (getpeereid(fd, &uid, &gid) < 0)
+  {
+    if (verbosity) strerr_warnwu1sys("getpeereid") ;
+    return 0 ;
+  }
+  switch (rulestype)
+  {
+    case 0 :
+      result = S6_ACCESSRULES_ALLOW ; break ;
+    case 1 :
+      result = s6_accessrules_uidgid_fs(uid, gid, rules, &params) ; break ;
+    case 2 :
+      result = s6_accessrules_uidgid_cdb(uid, gid, &cdbmap, &params) ; break ;
+    default : break ;
+  }
+  if (result != S6_ACCESSRULES_ALLOW)
+  {
+    if (verbosity && (result == S6_ACCESSRULES_ERROR))
+       strerr_warnw1sys("error while checking rules") ;
+    return 0 ;
+  }
+  if (params.exec.s)
+  {
+    stralloc_free(&params.exec) ;
+    if (verbosity)
+    {
+      char fmtuid[UID_FMT] ;
+      char fmtgid[GID_FMT] ;
+      fmtuid[uid_fmt(fmtuid, uid)] = 0 ;
+      fmtgid[gid_fmt(fmtgid, gid)] = 0 ;
+      strerr_warnw4x("unused exec string in rules for uid ", fmtuid, " gid ", fmtgid) ;
+    }
+  }
+  if (params.env.s)
+  {
+    size_t n = byte_count(params.env.s, params.env.len, '\0') ;
+    char const *envp[n+1] ;
+    if (!env_make(envp, n, params.env.s, params.env.len))
+    {
+      if (verbosity) strerr_warnwu1sys("env_make") ;
+      stralloc_free(&params.env) ;
+      return 0 ;
+    }
+    envp[n] = 0 ;
+    if (!parse_env(envp, idstr_re, flags))
+    {
+      if (verbosity) strerr_warnwu1sys("parse_env") ;
+      s6_accessrules_params_free(&params) ;
+      return 0 ;
+    }
+    s6_accessrules_params_free(&params) ;
+  }
+  return 1 ;
+}
+
+int main (int argc, char const *const *argv, char const *const *envp)
+{
+  int spfd ;
+  int flag1 = 0 ;
+  char const *announce_re = "^$" ;
+  unsigned int maxconn = 40 ;
+  PROG = "skabus-pubd" ;
+
+  {
+    subgetopt_t l = SUBGETOPT_ZERO ;
+    unsigned int t = 0, T = 0 ;
+    for (;;)
+    {
+      int opt = subgetopt_r(argc, argv, "v:Ss1c:k:i:x:t:T:", &l) ;
+      if (opt == -1) break ;
+      switch (opt)
+      {
+        case 'v' : if (!uint0_scan(l.arg, &verbosity)) dieusage() ; break ;
+        case 'S' : flagidstrpub = 0 ; break ;
+        case 's' : flagidstrpub = 1 ; break ;
+        case '1' : flag1 = 1 ; break ;
+        case 'k' : announce_re = l.arg ; break ;
+        case 'i' : rules = l.arg ; rulestype = 1 ; break ;
+        case 'x' : rules = l.arg ; rulestype = 2 ; break ;
+        case 't' : if (!uint0_scan(l.arg, &t)) dieusage() ; break ;
+        case 'T' : if (!uint0_scan(l.arg, &T)) dieusage() ; break ;
+        case 'c' : if (!uint0_scan(l.arg, &maxconn)) dieusage() ; break ;
+        default : dieusage() ;
+      }
+    }
+    argc -= l.ind ; argv += l.ind ;
+    if (t) tain_from_millisecs(&answertto, t) ;
+    if (T) tain_from_millisecs(&lameduckdeadline, T) ;
+  }
+  if (!argc) dieusage() ;
+  if (maxconn > SKABUS_PUB_MAX) maxconn = SKABUS_PUB_MAX ;
+  if (!maxconn) maxconn = 1 ;
+  {
+    struct stat st ;
+    if (fstat(0, &st) < 0) strerr_diefu1sys(111, "fstat stdin") ;
+    if (!S_ISSOCK(st.st_mode)) strerr_dief1x(100, "stdin is not a socket") ;
+  }
+  if (flag1)
+  {
+    if (fcntl(1, F_GETFD) < 0)
+      strerr_dief1sys(100, "called with option -1 but stdout said") ;
+  }
+  else fd_close(1) ;
+  {
+    struct stat st ;
+    if (stat(argv[0], &st) < 0)
+      strerr_diefu2sys(111, "stat ", argv[0]) ;
+    if (!S_ISDIR(st.st_mode))
+    {
+      errno = ENOTDIR ;
+      strerr_diefu2sys(100, "work in ", argv[0]) ;
+    }
+  }
+  msgfsdir = argv[0] ;
+  spfd = selfpipe_init() ;
+  if (spfd < 0) strerr_diefu1sys(111, "selfpipe_init") ;
+  if (sig_ignore(SIGPIPE) < 0) strerr_diefu1sys(111, "ignore SIGPIPE") ;
+  {
+    sigset_t set ;
+    sigemptyset(&set) ;
+    sigaddset(&set, SIGTERM) ;
+    sigaddset(&set, SIGHUP) ;
+    if (selfpipe_trapset(&set) < 0) strerr_diefu1sys(111, "trap signals") ;
+  }
+
+  if (rulestype == 2)
+  {
+    cdbfd = open_readb(rules) ;
+    if (cdbfd < 0) strerr_diefu3sys(111, "open ", rules, " for reading") ;
+    if (cdb_init(&cdbmap, cdbfd) < 0)
+      strerr_diefu2sys(111, "cdb_init ", rules) ;
+  }
+
+  {  /* I present to you: the stack */
+    GENSETB_TYPE(client_t, 1+maxconn) blob ;
+    iopause_fd x[2 + (maxconn << 1)] ;
+    AVLTREEN_DECLARE_AND_INIT(blobmap, 1+maxconn, &idstr_dtok, &idstr_cmp, &blob) ;
+
+    GENSETB_init(client_t, &blob, 1+maxconn) ;
+    clients = &blob.info ;
+    sentinel = gensetb_new(&blob) ;
+    blob.storage[sentinel].next = sentinel ;
+    blob.storage[sentinel].idstr[0] = 0 ;
+    {
+      int r = regcomp(&blob.storage[sentinel].subscribe_re, announce_re, REG_EXTENDED | REG_NOSUB) ;
+      if (r)
+      {
+        char buf[256] ;
+        regerror(r, &blob.storage[sentinel].subscribe_re, buf, 256) ;
+        strerr_dief4x(100, "invalid control regex: ", announce_re, ": ", buf) ;
+      }
+    }
+    if (regcomp(&blob.storage[sentinel].write_re, "^$", REG_NOSUB)) strerr_diefu1x(100, "regcomp ^$") ;
+    avltree_init(&blob.storage[sentinel].subscribers, 3, 3, 8, &uint32_dtok, &ptr_cmp, 0) ;
+    avltreen_insert(&blobmap, sentinel) ;
+    clientmap = &blobmap ;
+    x[0].fd = spfd ; x[0].events = IOPAUSE_READ ;
+    x[1].fd = 0 ;
+      
+    if (flag1)
+    {
+      fd_write(1, "\n", 1) ;
+      fd_close(1) ;
+    }
+    tain_now_g() ;
+
+    for (;;)
+    {
+      tain_t deadline ;
+      uint32_t i = blob.storage[sentinel].next, j = 2 ;
+      int r = 1 ;
+      if (cont) tain_add_g(&deadline, &tain_infinite_relative) ;
+      else deadline = lameduckdeadline ;
+      x[1].events = (cont && (numconn < maxconn)) ? IOPAUSE_READ : 0 ;
+      for (; i != sentinel ; i = blob.storage[i].next)
+        if (client_prepare_iopause(i, &deadline, x, &j)) r = 0 ;
+      if (!cont && r) break ;
+
+      r = iopause_g(x, j, &deadline) ;
+      if (r < 0) strerr_diefu1sys(111, "iopause") ;
+
+      if (!r)
+      {
+        for (j = sentinel, i = blob.storage[sentinel].next ; i != sentinel ; j = i, i = blob.storage[i].next)
+          if (!tain_future(&blob.storage[i].deadline))
+          {
+            char what[2] = "-" ;
+            what[1] = ETIMEDOUT ;
+            if (!announce(what, 2, CLIENT(i)->idstr)) dienomem() ;
+            remove(&i, j) ;
+          }
+        continue ;
+      }
+
+      if (x[0].revents & IOPAUSE_READ) handle_signals() ;
+
+      for (j = sentinel, i = blob.storage[sentinel].next ; i != sentinel ; j = i, i = blob.storage[i].next)
+        if (!client_flush(i, x)) remove(&i, j) ;
+
+      for (j = sentinel, i = blob.storage[sentinel].next ; i != sentinel ; j = i, i = blob.storage[i].next)
+        switch (client_read(i, x))
+        {
+          case 0 : errno = 0 ;
+          case -1 :
+          case -2 :
+          {
+            char what[2] = "-" ;
+            what[1] = errno ;
+            if (!announce(what, 2, CLIENT(i)->idstr)) dienomem() ;
+          }
+          remove(&i, j) ;
+          case 1 : break ;
+          default : errno = EILSEQ ; die() ;
+        }
+
+      if (x[1].revents & IOPAUSE_READ)
+      {
+        regex_t idstr_re ;
+        unsigned int flags = 0 ;
+        int fd = ipc_accept_nb(x[1].fd, 0, 0, 0) ;
+        if (fd < 0)
+          if (!error_isagain(errno)) strerr_diefu1sys(111, "accept") ;
+          else continue ;
+        else if (!new_connection(fd, &idstr_re, &flags)) fd_close(fd) ;
+        else client_add(fd, &idstr_re, flags) ;
+      }
+    }
+  }
+  return 0 ;
+}