Add skabus-rpc-daemon, skabus-rpcd and the skabus_rpc library

1 files changed, 542 insertions, 0 deletions

diff --git a/src/rpc/skabus-rpcd.c b/src/rpc/skabus-rpcd.c
new file mode 100644
index 0000000..36c6a78
--- /dev/null
+++ b/src/rpc/skabus-rpcd.c
@@ -0,0 +1,542 @@
+/* ISC license. */
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <stdint.h>
+#include <fcntl.h>
+#include <limits.h>
+#include <regex.h>
+#include <errno.h>
+#include <signal.h>
+#include <skalibs/uint32.h>
+#include <skalibs/uint64.h>
+#include <skalibs/types.h>
+#include <skalibs/bytestr.h>
+#include <skalibs/allreadwrite.h>
+#include <skalibs/error.h>
+#include <skalibs/cdb.h>
+#include <skalibs/strerr2.h>
+#include <skalibs/selfpipe.h>
+#include <skalibs/sig.h>
+#include <skalibs/djbunix.h>
+#include <skalibs/sgetopt.h>
+#include <skalibs/tai.h>
+#include <skalibs/iopause.h>
+#include <skalibs/env.h>
+#include <skalibs/getpeereid.h>
+#include <skalibs/webipc.h>
+#include <skalibs/genset.h>
+#include <skalibs/unixmessage.h>
+#include <s6/accessrules.h>
+#include <skabus/rpc.h>
+#include "skabus-rpcd.h"
+
+#define USAGE "skabus-rpcd [ -v verbosity ] [ -1 ] [ -d | -D ] [ -c maxconn ] [ -t timeout ] [ -T lameducktimeout ] [ -i rulesdir | -x rulesfile ] [ -S | -s ] [ -J | -j ]"
+#define dieusage() strerr_dieusage(100, USAGE) ;
+
+tain_t answertto = TAIN_INFINITE_RELATIVE ;
+
+static unsigned int verbosity = 1 ;
+static int cont = 1 ;
+static tain_t lameduckdeadline = TAIN_INFINITE_RELATIVE ;
+
+static unsigned int rulestype = 0 ;
+static char const *rules = 0 ;
+static int cdbfd = -1 ;
+static struct cdb cdbmap = CDB_ZERO ;
+static int flagidstrpub = 0, flaginterfacespub = 0 ;
+
+static inline 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 ;
+  }
+}
+
+int parse_protocol_async (unixmessage_t const *m, void *p)
+{
+  uint64_t serial ;
+  uint32_t qq ;
+  unixmessage_t mtosend = { .s = m->s + 10, .len = m->len - 10, .fds = m->fds, .nfds = m->nfds } ;
+  if (m->len < 10 || m->s[0] != 'R')
+  {
+    unixmessage_drop(m) ;
+    return (errno = EPROTO, 0) ;
+  }
+  uint64_unpack_big(m->s + 1, &serial) ;
+  if (!query_lookup_by_serial(serial, &qq))
+  {
+    unixmessage_drop(m) ;
+    return 1 ;
+  }
+  query_reply(qq, m->s[9], &mtosend) ;
+  return 1 ;
+}
+
+typedef int hlparsefunc_t (uint32_t, unixmessage_t *) ;
+typedef hlparsefunc_t *hlparsefunc_t_ref ;
+
+static int answer (uint32_t cc, char e)
+{
+  unixmessage_t m = { .s = &e, .len = 1, .fds = 0, .nfds = 0 } ;
+  client_t *c = CLIENT(cc) ;
+  if (!unixmessage_put(&c->sync.out, &m)) return 0 ;
+  if (client_isregistered(cc)) client_setdeadline(c) ;
+  return 1 ;
+}
+
+static int do_idstr (uint32_t cc, unixmessage_t *m)
+{
+  uint32_t relen, pmid, yy ;
+  unsigned char idlen ;
+  if (m->len < 11 || m->nfds) return (errno = EPROTO, 0) ;
+  uint32_unpack_big(m->s, &pmid) ;
+  idlen = m->s[4] ;
+  uint32_unpack_big(m->s + 5, &relen) ;
+  if (m->len != 11 + idlen + relen || m->s[9 + idlen] || m->s[10 + idlen + relen]) return (errno = EPROTO, 0) ;
+  if (client_isregistered(cc)) return answer(cc, EISCONN) ;
+  if (regexec(&CLIENT(cc)->idstr_re, m->s + 9, 0, 0, 0)) return answer(cc, EPERM) ;
+  m->s[8] = 0xff ;
+  if (interface_lookup_by_name(m->s + 8, &yy)) return answer(cc, EADDRINUSE) ;
+  if (!interface_add(&yy, m->s + 8, idlen + 1, cc, m->s + 10 + idlen, pmid))
+    return answer(cc, errno) ;
+  regfree(&CLIENT(cc)->idstr_re) ;
+  return answer(cc, 0) ;
+}
+
+static int do_interface_register (uint32_t cc, unixmessage_t *m)
+{
+  uint32_t id, relen, yy ;
+  unsigned char iflen ;
+  if (m->len < 11 || m->nfds) return (errno = EPROTO, 0) ;
+  uint32_unpack_big(m->s, &id) ;
+  iflen = m->s[4] ;
+  uint32_unpack_big(m->s + 5, &relen) ;
+  if (m->len != 11 + iflen + relen) return (errno = EPROTO, 0) ;
+  if (m->s[9 + iflen] || m->s[10 + iflen + relen]) return (errno = EPROTO, 0) ;
+  if (!client_isregistered(cc)) return answer(cc, ENOTCONN) ;
+  if (regexec(&CLIENT(cc)->interfaces_re, m->s + 9, 0, 0, 0)) return answer(cc, EPERM) ;
+  if (interface_lookup_by_name(m->s + 9, &yy)) return answer(cc, EADDRINUSE) ;
+  if (!interface_add(&yy, m->s + 9, iflen, cc, m->s + 10 + iflen, id)) return answer(cc, errno) ;
+  return answer(cc, 0) ;
+}
+
+static int do_interface_unregister (uint32_t cc, unixmessage_t *m)
+{
+  uint32_t yy ;
+  unsigned char iflen ;
+  if (!m->len || m->nfds) return (errno = EPROTO, 0) ;
+  iflen = m->s[0] ;
+  if ((m->len != iflen + 2) || m->s[iflen+1]) return (errno = EPROTO, 0) ;
+  if (!client_isregistered(cc)) return answer(cc, ENOTCONN) ;
+  if (!iflen || ((unsigned char const *)m->s)[1] == 0xff) return answer(cc, EINVAL) ;
+  if (!interface_lookup_by_name(m->s + 1, &yy)) return answer(cc, errno) ;
+  if (INTERFACE(yy)->client != cc) return answer(cc, EPERM) ;
+  interface_remove(yy) ;
+  return answer(cc, 0) ;
+}
+
+static int do_query_send (uint32_t cc, unixmessage_t *m)
+{
+  tain_t limit ;
+  uint32_t yy, qq ;
+  unsigned char iflen ;
+  int e ;
+  if (m->len < 2 + TAIN_PACK) return (errno = EPROTO, 0) ;
+  tain_unpack(m->s, &limit) ;
+  iflen = m->s[TAIN_PACK] ;
+  if (m->len < 2 + TAIN_PACK + iflen || m->s[TAIN_PACK + 1 + iflen]) return (errno = EPROTO, 0) ;
+  if (!client_isregistered(cc)) { e = ENOTCONN ; goto nope ; }
+  if (!interface_lookup_by_name(m->s + TAIN_PACK + 1, &yy)) { e = ESRCH ; goto nope ; }
+  if (regexec(&INTERFACE(yy)->re, client_idstr(CLIENT(cc)), 0, 0, 0)) { e = EPERM ; goto nope ; }
+  m->s += 2 + TAIN_PACK + iflen ;
+  m->len -= 2 + TAIN_PACK + iflen ;
+  if (!query_add(&qq, &limit, cc, yy) || !query_send(qq, m)) { e = errno ; goto nope ; }
+  return answer(cc, 0) ;
+
+ nope:
+  if (!answer(cc, e)) return 0 ;
+  unixmessage_drop(m) ;
+  return 1 ;
+}
+
+static int do_query_cancel (uint32_t cc, unixmessage_t *m)
+{
+  uint64_t serial ;
+  uint32_t qq ;
+  if (m->len != 8 || m->nfds) return (errno = EPROTO, 0) ;
+  if (!client_isregistered(cc)) return answer(cc, ENOTCONN) ;
+  uint64_unpack_big(m->s, &serial) ;
+  if (!query_lookup_by_serial(serial, &qq)) return answer(cc, errno) ;
+  if (cc != QUERY(qq)->client) return answer(cc, EPERM) ;
+  if (!query_cancelremove(qq, 0)) return answer(cc, errno) ;
+  return answer(cc, 0) ;
+}
+
+static int do_error (uint32_t cc, unixmessage_t *m)
+{
+  (void)cc ;
+  (void)m ;
+  return (errno = EPROTO, 0) ;
+}
+
+int parse_protocol_sync (unixmessage_t const *m, void *p)
+{
+  static hlparsefunc_t_ref const f[6] =
+  {
+    &do_idstr,
+    &do_interface_register,
+    &do_interface_unregister,
+    &do_query_send,
+    &do_query_cancel,
+    &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("SIiQC", 5, m->s[0])])(*(uint32_t *)p, &mcopy))
+  {
+    unixmessage_drop(m) ;
+    return 0 ;
+  }
+  return 1 ;
+}
+
+static void removeclient (uint32_t *i, uint32_t j)
+{
+  if (verbosity >= 2)
+  {
+    char fmt[UINT32_FMT] ;
+    fmt[uint32_fmt(fmt, *i)] = 0 ;
+    strerr_warni2sys("removing client ", fmt) ;
+  }
+  client_remove(*i, j) ;
+  *i = j ;
+}
+
+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, regex_t *interfaces_re, uint32_t *flags)
+{
+  uint32_t fl = 0 ;
+  int idstr_done = 0, interfaces_done = 0 ;
+  for (; *envp ; envp++)
+  {
+    if (str_start(*envp, "SKABUS_RPC_QSENDFDS=")) fl |= 1 ;
+    if (str_start(*envp, "SKABUS_RPC_RSENDFDS=")) fl |= 2 ;
+    if (!idstr_done)
+    {
+      idstr_done = makere(idstr_re, *envp, "SKABUS_RPC_ID_REGEX") ;
+      if (idstr_done < 0)
+      {
+        if (interfaces_done) regfree(interfaces_re) ;
+        return 0 ;
+      }
+    }
+    if (!interfaces_done)
+    {
+      interfaces_done = makere(interfaces_re, *envp, "SKABUS_RPC_INTERFACES_REGEX") ;
+      if (interfaces_done < 0)
+      {
+        if (idstr_done) regfree(idstr_re) ;
+        return 0 ;
+      }
+    }
+    if (idstr_done && interfaces_done) return 1 ;
+  }
+  if (!idstr_done) defaultre(idstr_re, flagidstrpub) ;
+  if (!interfaces_done) defaultre(interfaces_re, flaginterfacespub) ;
+  *flags = fl ;
+  return 1 ;
+}
+
+static inline int new_connection (int fd, uid_t *uid, gid_t *gid, regex_t *idstr_re, regex_t *interfaces_re, uint32_t *flags)
+{
+  s6_accessrules_params_t params = S6_ACCESSRULES_PARAMS_ZERO ;
+  s6_accessrules_result_t result = S6_ACCESSRULES_ERROR ;
+
+  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, interfaces_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 ;
+  uint32_t maxconn = 64 ;
+  PROG = "skabus-rpcd" ;
+
+  {
+    subgetopt_t l = SUBGETOPT_ZERO ;
+    unsigned int t = 0, T = 0 ;
+    for (;;)
+    {
+      int opt = subgetopt_r(argc, argv, "v:SsJj1i:x:t:T:c:", &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 'J' : flaginterfacespub = 0 ; break ;
+        case 'j' : flaginterfacespub = 1 ; break ;
+        case '1' : flag1 = 1 ; 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 (!uint320_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 (maxconn > SKABUS_RPC_MAX) maxconn = SKABUS_RPC_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 close(1) ;
+  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) ;
+  }
+
+  {
+    GENSETB_TYPE(client_t, 1+maxconn) blob ;
+    iopause_fd x[2 + (maxconn << 1)] ;
+    GENSETB_init(client_t, &blob, 1+maxconn) ;
+    sentinel = gensetb_new(&blob) ;
+    blob.storage[sentinel].next = sentinel ;
+    clients = &blob.info ;
+    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 ;
+      int r = 1 ;
+      uint32_t i = blob.storage[sentinel].next, j = 2 ;
+      query_get_mindeadline(&deadline) ;
+      if (!cont && tain_less(&lameduckdeadline, &deadline)) deadline = lameduckdeadline ;
+      if (queries_pending()) r = 0 ;
+      
+      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, cont)) r = 0 ;
+      if (!cont && r) break ;
+
+      r = iopause_g(x, j, &deadline) ;
+      if (r < 0) strerr_diefu1sys(111, "iopause") ;
+
+
+     /* Timeout */
+
+      if (!r)
+      {
+        if (!cont && !tain_future(&lameduckdeadline)) return 1 ;
+        for (;;)
+        {
+          if (!query_lookup_by_mindeadline(&i)) break ;
+          if (tain_future(&QUERY(i)->deadline)) break ;
+          query_fail(i, ETIMEDOUT) ;
+        }
+        errno = ETIMEDOUT ;
+        for (i = blob.storage[sentinel].next, j = sentinel ; i != sentinel ; j = i, i = blob.storage[i].next)
+          if (!tain_future(&blob.storage[i].deadline)) removeclient(&i, j) ;
+        continue ;
+      }
+
+
+     /* Signal */
+
+      if (x[0].revents & IOPAUSE_READ) handle_signals() ;
+
+
+     /* Event */
+
+      for (j = sentinel, i = blob.storage[sentinel].next ; i != sentinel ; j = i, i = blob.storage[i].next)
+        if (!client_flush(i, x)) removeclient(&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 :
+          {
+            removeclient(&i, j) ;
+            break ;
+          }
+          case 1 : break ;
+          default : X() ;
+        }
+
+
+      /* New connection */
+
+      if (x[1].revents & IOPAUSE_READ)
+      {
+        uint32_t flags = 0 ;
+        uid_t uid ;
+        gid_t gid ;
+        regex_t idstr_re, interfaces_re ;
+        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, &uid, &gid, &idstr_re, &interfaces_re, &flags))
+          fd_close(fd) ;
+        else client_add(&i, &idstr_re, &interfaces_re, uid, gid, fd, flags) ;
+      }
+    }
+  }
+  return 0 ;
+}