Refactor libs6auto, add s6-instance-maker (untested)

Signed-off-by: Laurent Bercot <ska@appnovation.com>

17 files changed, 497 insertions, 201 deletions

diff --git a/.gitignore b/.gitignore
index d08a569..08ecbf7 100644
--- a/.gitignore
+++ b/.gitignore
@@ -71,3 +71,4 @@
 /s6-applyuidgid
 /s6-setuidgid
 /s6-usertree-maker
+/s6-instance-maker
diff --git a/doc/s6-setuidgid.html b/doc/s6-setuidgid.html
index 95e0e2d..eb4e7f6 100644
--- a/doc/s6-setuidgid.html
+++ b/doc/s6-setuidgid.html
@@ -29,6 +29,8 @@ s6-setuidgid executes a program as another user.
 </pre>
 
 <ul>
+ <li> If <em>account</em> is the empty string, then s6-setuidgid directly execs
+into <em>prog...</em> without any state changes. </li>
  <li> If <em>account</em> contains a colon, it is interpreted as <em>uid:gid</em>,
 else it is interpreted as a username and looked up by name in the account
 database. </li>
@@ -41,10 +43,10 @@ according to the group database. </li>
 
 <h2> Notes </h2>
 
-<p>
- s6-setuidgid can only be run as root. Its main use is to drop root privileges before
-starting a daemon.
-</p>
+<ul>
+ <li> Unless <em>account</em> is empty, s6-setuidgid can only be run as root. Its main use
+is to drop root privileges before starting a daemon. </li>
+</ul>
 
 </body>
 </html>
diff --git a/package/deps.mak b/package/deps.mak
index 58d497d..7aad077 100644
--- a/package/deps.mak
+++ b/package/deps.mak
@@ -42,6 +42,7 @@ src/fdholder/s6-fdholder-setdump.o src/fdholder/s6-fdholder-setdump.lo: src/fdho
 src/fdholder/s6-fdholder-store.o src/fdholder/s6-fdholder-store.lo: src/fdholder/s6-fdholder-store.c src/include/s6/fdholder.h
 src/fdholder/s6-fdholder-transferdump.o src/fdholder/s6-fdholder-transferdump.lo: src/fdholder/s6-fdholder-transferdump.c src/include/s6/fdholder.h
 src/fdholder/s6-fdholderd.o src/fdholder/s6-fdholderd.lo: src/fdholder/s6-fdholderd.c src/include/s6/accessrules.h src/include/s6/fdholder.h
+src/instance/s6-instance-maker.o src/instance/s6-instance-maker.lo: src/instance/s6-instance-maker.c src/include/s6/auto.h src/include/s6/config.h
 src/libs6/ftrig1_free.o src/libs6/ftrig1_free.lo: src/libs6/ftrig1_free.c src/libs6/ftrig1.h
 src/libs6/ftrig1_make.o src/libs6/ftrig1_make.lo: src/libs6/ftrig1_make.c src/libs6/ftrig1.h
 src/libs6/ftrigr1_zero.o src/libs6/ftrigr1_zero.lo: src/libs6/ftrigr1_zero.c src/include/s6/ftrigr.h
@@ -73,7 +74,11 @@ src/libs6/s6_accessrules_keycheck_uidgid.o src/libs6/s6_accessrules_keycheck_uid
 src/libs6/s6_accessrules_params_free.o src/libs6/s6_accessrules_params_free.lo: src/libs6/s6_accessrules_params_free.c src/include/s6/accessrules.h
 src/libs6/s6_accessrules_uidgid_cdb.o src/libs6/s6_accessrules_uidgid_cdb.lo: src/libs6/s6_accessrules_uidgid_cdb.c src/include/s6/accessrules.h
 src/libs6/s6_accessrules_uidgid_fs.o src/libs6/s6_accessrules_uidgid_fs.lo: src/libs6/s6_accessrules_uidgid_fs.c src/include/s6/accessrules.h
-src/libs6/s6_auto_write_logrun.o src/libs6/s6_auto_write_logrun.lo: src/libs6/s6_auto_write_logrun.c src/include/s6/auto.h src/include/s6/config.h
+src/libs6/s6_auto_write_logger.o src/libs6/s6_auto_write_logger.lo: src/libs6/s6_auto_write_logger.c src/include/s6/auto.h
+src/libs6/s6_auto_write_logger_tmp.o src/libs6/s6_auto_write_logger_tmp.lo: src/libs6/s6_auto_write_logger_tmp.c src/include/s6/auto.h
+src/libs6/s6_auto_write_logrun.o src/libs6/s6_auto_write_logrun.lo: src/libs6/s6_auto_write_logrun.c src/include/s6/auto.h
+src/libs6/s6_auto_write_logrun_tmp.o src/libs6/s6_auto_write_logrun_tmp.lo: src/libs6/s6_auto_write_logrun_tmp.c src/include/s6/auto.h src/include/s6/config.h
+src/libs6/s6_auto_write_service.o src/libs6/s6_auto_write_service.lo: src/libs6/s6_auto_write_service.c src/include/s6/auto.h
 src/libs6/s6_compat_el_semicolon.o src/libs6/s6_compat_el_semicolon.lo: src/libs6/s6_compat_el_semicolon.c src/include/s6/config.h
 src/libs6/s6_dtally_pack.o src/libs6/s6_dtally_pack.lo: src/libs6/s6_dtally_pack.c src/include/s6/supervise.h
 src/libs6/s6_dtally_read.o src/libs6/s6_dtally_read.lo: src/libs6/s6_dtally_read.c src/include/s6/supervise.h
@@ -212,6 +217,8 @@ s6-fdholder-transferdump: EXTRA_LIBS := -lskarnet ${SOCKET_LIB} ${SYSCLOCK_LIB}
 s6-fdholder-transferdump: src/fdholder/s6-fdholder-transferdump.o ${LIBS6}
 s6-fdholderd: EXTRA_LIBS := -lskarnet ${SOCKET_LIB} ${SYSCLOCK_LIB}
 s6-fdholderd: src/fdholder/s6-fdholderd.o ${LIBS6}
+s6-instance-maker: EXTRA_LIBS := -lskarnet
+s6-instance-maker: src/instance/s6-instance-maker.o libs6auto.a.xyzzy
 ifeq ($(strip $(STATIC_LIBS_ARE_PIC)),)
 libs6.a.xyzzy: src/libs6/ftrigr1_zero.o src/libs6/ftrigr_check.o src/libs6/ftrigr_checksa.o src/libs6/ftrigr_ack.o src/libs6/ftrigr_end.o src/libs6/ftrigr_start.o src/libs6/ftrigr_startf.o src/libs6/ftrigr_subscribe.o src/libs6/ftrigr_unsubscribe.o src/libs6/ftrigr_update.o src/libs6/ftrigr_updateb.o src/libs6/ftrigr_wait_and.o src/libs6/ftrigr_wait_or.o src/libs6/ftrigr_zero.o src/libs6/ftrigw_clean.o src/libs6/ftrigw_fifodir_make.o src/libs6/ftrigw_notify.o src/libs6/ftrigw_notifyb.o src/libs6/ftrigw_notifyb_nosig.o src/libs6/s6_accessrules_backend_cdb.o src/libs6/s6_accessrules_backend_fs.o src/libs6/s6_accessrules_keycheck_ip4.o src/libs6/s6_accessrules_keycheck_ip6.o src/libs6/s6_accessrules_keycheck_reversedns.o src/libs6/s6_accessrules_keycheck_uidgid.o src/libs6/s6_accessrules_params_free.o src/libs6/s6_accessrules_uidgid_cdb.o src/libs6/s6_accessrules_uidgid_fs.o src/libs6/s6_compat_el_semicolon.o src/libs6/s6_dtally_pack.o src/libs6/s6_dtally_unpack.o src/libs6/s6_dtally_read.o src/libs6/s6_dtally_write.o src/libs6/s6_servicedir_file_list.o src/libs6/s6_svc_ok.o src/libs6/s6_svc_write.o src/libs6/s6_svc_writectl.o src/libs6/s6_svstatus_pack.o src/libs6/s6_svstatus_read.o src/libs6/s6_svstatus_unpack.o src/libs6/s6_svstatus_write.o src/libs6/s6lock_acquire.o src/libs6/s6lock_check.o src/libs6/s6lock_end.o src/libs6/s6lock_release.o src/libs6/s6lock_start.o src/libs6/s6lock_startf.o src/libs6/s6lock_update.o src/libs6/s6lock_wait_and.o src/libs6/s6lock_wait_or.o src/libs6/s6lock_zero.o src/libs6/s6_fdholder_delete.o src/libs6/s6_fdholder_delete_async.o src/libs6/s6_fdholder_end.o src/libs6/s6_fdholder_getdump.o src/libs6/s6_fdholder_list.o src/libs6/s6_fdholder_list_async.o src/libs6/s6_fdholder_list_cb.o src/libs6/s6_fdholder_retrieve.o src/libs6/s6_fdholder_retrieve_async.o src/libs6/s6_fdholder_retrieve_cb.o src/libs6/s6_fdholder_setdump.o src/libs6/s6_fdholder_start.o src/libs6/s6_fdholder_store.o src/libs6/s6_fdholder_store_async.o src/libs6/s6_supervise_link.o src/libs6/s6_supervise_link_names.o src/libs6/s6_supervise_unlink.o src/libs6/s6_supervise_unlink_names.o
 else
@@ -220,12 +227,12 @@ endif
 libs6.so.xyzzy: EXTRA_LIBS := -lskarnet
 libs6.so.xyzzy: src/libs6/ftrigr1_zero.lo src/libs6/ftrigr_check.lo src/libs6/ftrigr_checksa.lo src/libs6/ftrigr_ack.lo src/libs6/ftrigr_end.lo src/libs6/ftrigr_start.lo src/libs6/ftrigr_startf.lo src/libs6/ftrigr_subscribe.lo src/libs6/ftrigr_unsubscribe.lo src/libs6/ftrigr_update.lo src/libs6/ftrigr_updateb.lo src/libs6/ftrigr_wait_and.lo src/libs6/ftrigr_wait_or.lo src/libs6/ftrigr_zero.lo src/libs6/ftrigw_clean.lo src/libs6/ftrigw_fifodir_make.lo src/libs6/ftrigw_notify.lo src/libs6/ftrigw_notifyb.lo src/libs6/ftrigw_notifyb_nosig.lo src/libs6/s6_accessrules_backend_cdb.lo src/libs6/s6_accessrules_backend_fs.lo src/libs6/s6_accessrules_keycheck_ip4.lo src/libs6/s6_accessrules_keycheck_ip6.lo src/libs6/s6_accessrules_keycheck_reversedns.lo src/libs6/s6_accessrules_keycheck_uidgid.lo src/libs6/s6_accessrules_params_free.lo src/libs6/s6_accessrules_uidgid_cdb.lo src/libs6/s6_accessrules_uidgid_fs.lo src/libs6/s6_compat_el_semicolon.lo src/libs6/s6_dtally_pack.lo src/libs6/s6_dtally_unpack.lo src/libs6/s6_dtally_read.lo src/libs6/s6_dtally_write.lo src/libs6/s6_servicedir_file_list.lo src/libs6/s6_svc_ok.lo src/libs6/s6_svc_write.lo src/libs6/s6_svc_writectl.lo src/libs6/s6_svstatus_pack.lo src/libs6/s6_svstatus_read.lo src/libs6/s6_svstatus_unpack.lo src/libs6/s6_svstatus_write.lo src/libs6/s6lock_acquire.lo src/libs6/s6lock_check.lo src/libs6/s6lock_end.lo src/libs6/s6lock_release.lo src/libs6/s6lock_start.lo src/libs6/s6lock_startf.lo src/libs6/s6lock_update.lo src/libs6/s6lock_wait_and.lo src/libs6/s6lock_wait_or.lo src/libs6/s6lock_zero.lo src/libs6/s6_fdholder_delete.lo src/libs6/s6_fdholder_delete_async.lo src/libs6/s6_fdholder_end.lo src/libs6/s6_fdholder_getdump.lo src/libs6/s6_fdholder_list.lo src/libs6/s6_fdholder_list_async.lo src/libs6/s6_fdholder_list_cb.lo src/libs6/s6_fdholder_retrieve.lo src/libs6/s6_fdholder_retrieve_async.lo src/libs6/s6_fdholder_retrieve_cb.lo src/libs6/s6_fdholder_setdump.lo src/libs6/s6_fdholder_start.lo src/libs6/s6_fdholder_store.lo src/libs6/s6_fdholder_store_async.lo src/libs6/s6_supervise_link.lo src/libs6/s6_supervise_link_names.lo src/libs6/s6_supervise_unlink.lo src/libs6/s6_supervise_unlink_names.lo
 ifeq ($(strip $(STATIC_LIBS_ARE_PIC)),)
-libs6auto.a.xyzzy: src/libs6/s6_auto_write_logrun.o
+libs6auto.a.xyzzy: src/libs6/s6_auto_write_logger.o src/libs6/s6_auto_write_logger_tmp.o src/libs6/s6_auto_write_logrun.o src/libs6/s6_auto_write_logrun_tmp.o src/libs6/s6_auto_write_service.o
 else
-libs6auto.a.xyzzy: src/libs6/s6_auto_write_logrun.lo
+libs6auto.a.xyzzy: src/libs6/s6_auto_write_logger.lo src/libs6/s6_auto_write_logger_tmp.lo src/libs6/s6_auto_write_logrun.lo src/libs6/s6_auto_write_logrun_tmp.lo src/libs6/s6_auto_write_service.lo
 endif
 libs6auto.so.xyzzy: EXTRA_LIBS :=
-libs6auto.so.xyzzy: src/libs6/s6_auto_write_logrun.lo
+libs6auto.so.xyzzy: src/libs6/s6_auto_write_logger.lo src/libs6/s6_auto_write_logger_tmp.lo src/libs6/s6_auto_write_logrun.lo src/libs6/s6_auto_write_logrun_tmp.lo src/libs6/s6_auto_write_service.lo
 ifeq ($(strip $(STATIC_LIBS_ARE_PIC)),)
 libs6lockd.a.xyzzy: src/libs6/s6lockd_openandlock.o
 else
diff --git a/package/modes b/package/modes
index 6c3c27d..a0ee4ae 100644
--- a/package/modes
+++ b/package/modes
@@ -65,3 +65,4 @@ s6-fdholder-setdumpc		0755
 s6-fdholder-transferdump	0755
 s6-fdholder-transferdumpc	0755
 s6-usertree-maker		0755
+s6-instance-maker		0755
diff --git a/package/targets.mak b/package/targets.mak
index bfbf3a6..2f6f81a 100644
--- a/package/targets.mak
+++ b/package/targets.mak
@@ -64,5 +64,5 @@ LIB_DEFS := S6=s6
 
 ifneq ($(EXECLINE_LIB),)
 LIB_DEFS += S6AUTO=s6auto
-BIN_TARGETS += s6-usertree-maker
+BIN_TARGETS += s6-usertree-maker s6-instance-maker
 endif
diff --git a/src/daemontools-extras/s6-setuidgid.c b/src/daemontools-extras/s6-setuidgid.c
index 26256b8..a1afc66 100644
--- a/src/daemontools-extras/s6-setuidgid.c
+++ b/src/daemontools-extras/s6-setuidgid.c
@@ -10,7 +10,7 @@
 #define USAGE "s6-setuidgid username prog..."
 #define dieusage() strerr_dieusage(100, USAGE)
 
-int main (int argc, char *const *argv)
+int main (int argc, char const *const *argv)
 {
   char const *newargv[argc + 7] ;
   char *colon ;
@@ -18,6 +18,7 @@ int main (int argc, char *const *argv)
   PROG = "s6-setuidgid" ;
   if (argc < 3) dieusage() ;
   argv++ ;
+  if (!argv[0][0]) xexec(argv+1) ;
   colon = strchr(argv[0], ':') ;
   if (colon)
   {
diff --git a/src/include/s6/auto.h b/src/include/s6/auto.h
index b8faff6..cab4b80 100644
--- a/src/include/s6/auto.h
+++ b/src/include/s6/auto.h
@@ -4,8 +4,18 @@
 #define S6_AUTO_H
 
 #include <skalibs/uint64.h>
+#include <skalibs/buffer.h>
 #include <skalibs/stralloc.h>
 
-int s6_auto_write_logrun (char const *, char const *, char const *, unsigned int, unsigned int, uint64_t, uint64_t, stralloc *) ;
+typedef int s6_buffer_writer_func (buffer *, void *) ;
+typedef s6_buffer_writer_func *s6_buffer_writer_func_ref ;
+
+extern int s6_auto_write_logrun (char const *, char const *, char const *, unsigned int, unsigned int, uint64_t, uint64_t, char const *) ;
+extern int s6_auto_write_logrun_tmp (char const *, char const *, char const *, unsigned int, unsigned int, uint64_t, uint64_t, char const *, stralloc *) ;
+
+extern void s6_auto_write_logger (char const *, char const *, char const *, unsigned int, unsigned int, uint64_t, uint64_t, char const *, char const *, char const *) ;
+extern void s6_auto_write_logger_tmp (char const *, char const *, char const *, unsigned int, unsigned int, uint64_t, uint64_t, char const *, char const *, char const *, stralloc *sa) ;
+
+extern void s6_auto_write_service (char const *, unsigned int, s6_buffer_writer_func_ref, void *, char const *) ;
 
 #endif
diff --git a/src/instance/deps-exe/s6-instance-maker b/src/instance/deps-exe/s6-instance-maker
new file mode 100644
index 0000000..750e758
--- /dev/null
+++ b/src/instance/deps-exe/s6-instance-maker
@@ -0,0 +1,2 @@
+libs6auto.a.xyzzy
+-lskarnet
diff --git a/src/instance/s6-instance-maker.c b/src/instance/s6-instance-maker.c
new file mode 100644
index 0000000..20f557f
--- /dev/null
+++ b/src/instance/s6-instance-maker.c
@@ -0,0 +1,181 @@
+/* ISC license. */
+
+#include <errno.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <sys/uio.h>
+
+#include <skalibs/uint64.h>
+#include <skalibs/types.h>
+#include <skalibs/buffer.h>
+#include <skalibs/strerr.h>
+#include <skalibs/sgetopt.h>
+#include <skalibs/stralloc.h>
+#include <skalibs/djbunix.h>
+#include <skalibs/skamisc.h>
+
+#include <execline/config.h>
+
+#include <s6/config.h>
+#include <s6/auto.h>
+
+#define USAGE "s6-instance-maker [ -c max ] [ -u user ] [ -l loguser ] [ -L logdir ] [ -t stamptype ] [ -n nfiles ] [ -s filesize ] [ -S maxsize ] [ -P prefix ] [ -r service[/logger[/pipeline]] ] template dir"
+#define dieusage() strerr_dieusage(100, USAGE)
+
+typedef struct svinfo_s svinfo, *svinfo_ref ;
+struct svinfo_s
+{
+  char const *user ;
+  unsigned int maxinstances ;
+} ;
+
+static stralloc sa = STRALLOC_ZERO ;
+
+static int write_run (buffer *b, void *data)
+{
+  svinfo *t = data ;
+  size_t l ;
+  char fmt[UINT_FMT] ;
+  l = uint_fmt(fmt, t->maxinstances) ;
+  if (buffer_puts(b, EXECLINE_EXTBINPREFIX "execlineb -S1\n\n"
+    EXECLINE_EXTBINPREFIX "fdmove -c 2 1\n") < 0) return 0 ;
+  if (t->user)
+  {
+    if (!string_quote(&sa, t->user, strlen(t->user))) return 0 ;
+    if (buffer_puts(b, S6_EXTBINPREFIX "s6-setuidgid ") < 0
+     || buffer_put(b, sa.s, sa.len) < 0
+     || buffer_put(b, "\n", 1) < 0) goto err ;
+    sa.len = 0 ;
+  }
+  if (buffer_puts(b, S6_EXTBINPREFIX "s6-svscan -d3 -c") < 0
+   || buffer_put(b, fmt, l) < 0
+   || buffer_putsflush(b, " -- instance\n") < 0) return 0 ;
+  return 1 ;
+
+err:
+  sa.len = 0 ;
+  return 0 ;
+}
+
+static void write_service (char const *dir, char const *template, char const *user, unsigned int maxinstances, char const *logger)
+{
+  svinfo data = { .user = user, .maxinstances = maxinstances } ;
+  size_t dirlen = strlen(dir) ;
+  mode_t m = umask(0) ;
+  char fn[dirlen + 21] ;
+  memcpy(fn, dir, dirlen) ;
+  memcpy(fn + dirlen, "/instance", 10) ;
+  m = umask(0) ;
+  if (mkdir(fn, 0755) == -1) strerr_diefu2sys(111, "mkdir ", fn) ;
+  memcpy(fn + dirlen + 9, "s", 2) ;
+  if (mkdir(fn, 0755) == -1) strerr_diefu2sys(111, "mkdir ", fn) ;
+  umask(m) ;
+  memcpy(fn + dirlen + 10, "/.template", 11) ;
+  if (!hiercopy_tmp(template, fn, &sa))
+    strerr_diefu4sys(111, "copy file hierarchy from ", template, " to ", fn) ;
+  s6_auto_write_service(dir, 3, &write_run, &data, logger) ;
+}
+
+int main (int argc, char const *const *argv)
+{
+  char const *user = "" ;
+  char const *loguser = 0 ;
+  char const *logdir = 0 ;
+  unsigned int maxinstances = 500 ;
+  unsigned int stamptype = 1 ;
+  unsigned int nfiles = 10 ;
+  uint64_t filesize = 1000000 ;
+  uint64_t maxsize = 0 ;
+  char const *prefix = 0 ;
+  char *rcinfo[3] = { 0, 0, 0 } ;
+  size_t dirlen ;
+  PROG = "s6-instance-maker" ;
+  {
+    subgetopt l = SUBGETOPT_ZERO ;
+    for (;;)
+    {
+      int opt = subgetopt_r(argc, argv, "u:l:L:c:t:n:s:S:P:r:", &l) ;
+      if (opt == -1) break ;
+      switch (opt)
+      {
+        case 'u' : user = l.arg ; break ;
+        case 'l' : loguser = l.arg ; break ;
+        case 'L' : logdir = l.arg ; break ;
+        case 'c' : if (!uint0_scan(l.arg, &maxinstances)) dieusage() ; break ;
+        case 't' : if (!uint0_scan(l.arg, &stamptype)) dieusage() ; break ;
+        case 'n' : if (!uint0_scan(l.arg, &nfiles)) dieusage() ; break ;
+        case 's' : if (!uint640_scan(l.arg, &filesize)) dieusage() ; break ;
+        case 'S' : if (!uint640_scan(l.arg, &maxsize)) dieusage() ; break ;
+        case 'P' : prefix = l.arg ; break ;
+	case 'r' : rcinfo[0] = (char *)l.arg ; break ;
+        default : dieusage() ;
+      }
+    }
+    argc -= l.ind ; argv += l.ind ;
+  }
+
+  if (argc < 2) dieusage() ;
+  if (logdir && logdir[0] != '/')
+    strerr_dief1x(100, "logdir must be absolute") ;
+  if (stamptype > 3) strerr_dief1x(100, "stamptype must be 0, 1, 2 or 3") ;
+  if (strchr(user, ' ') || strchr(user, '\t') || strchr(user, '\n'))
+    strerr_dief1x(100, "invalid user") ;
+  if (maxinstances < 1) maxinstances = 1 ;
+  if (maxinstances > 90000) maxinstances = 90000 ;
+  if (rcinfo[0])
+  {
+    if (strchr(rcinfo[0], '\n'))
+      strerr_dief2x(100, "newlines", " are forbidden in s6-rc names") ;
+    if (rcinfo[0][0] == '/')
+      strerr_dief2x(100, "service", " name cannot be empty") ;
+    rcinfo[1] = strchr(rcinfo[0], '/') ;
+    if (rcinfo[1])
+    {
+      *rcinfo[1]++ = 0 ;
+      if (!rcinfo[1][0]) strerr_dief1x(100, "argument to -r must be: service or service/logger or service/logger/pipeline") ;
+      if (rcinfo[1][0] == '/')
+        strerr_dief2x(100, "logger", " name cannot be empty") ;
+      if (!logdir) strerr_dief1x(100, "logger specifiec (-r) but logdir not specified (-L)") ;
+      rcinfo[2] = strchr(rcinfo[1], '/') ;
+      if (rcinfo[2])
+      {
+        *rcinfo[2]++ = 0 ;
+        if (!rcinfo[2][0]) strerr_dief2x(100, "pipeline", " name cannot be empty") ;
+        if (strchr(rcinfo[2], '/')) strerr_dief2x(100, "slashes", " are forbidden in s6-rc names") ;
+      }
+    }
+    else if (logdir)
+      strerr_dief1x(100, "logdir specified (-L) but logger name not specified (-r)") ;
+  }
+
+  dirlen = strlen(argv[1]) ;
+  if (rcinfo[0])
+  {
+    size_t svclen = strlen(rcinfo[0]) ;
+    size_t loglen = rcinfo[1] ? strlen(rcinfo[1]) : 0 ;
+    char dir[dirlen + 2 + (svclen > loglen ? svclen : loglen)] ;
+    memcpy(dir, argv[1], dirlen) ;
+    dir[dirlen] = '/' ;
+    if (mkdir(argv[1], 0755) < 0 && errno != EEXIST)
+      strerr_diefu2sys(111, "mkdir ", argv[2]) ;
+    memcpy(dir + dirlen + 1, rcinfo[0], svclen + 1) ;
+    write_service(dir, user, argv[0], maxinstances, rcinfo[1] ? rcinfo[1] : "") ;
+    if (rcinfo[1])
+    {
+      memcpy(dir + dirlen + 1, rcinfo[1], loglen + 1) ;
+      s6_auto_write_logger_tmp(dir, loguser, logdir, stamptype, nfiles, filesize, maxsize, prefix, rcinfo[0], rcinfo[2], &sa) ;
+    }
+  }
+  else
+  {
+    write_service(argv[1], user, argv[0], maxinstances, 0) ;
+    if (logdir)
+    {
+      char dir[dirlen + 5] ;
+      memcpy(dir, argv[1], dirlen) ;
+      memcpy(dir + dirlen, "/log", 5) ;
+      s6_auto_write_logger_tmp(dir, loguser, logdir, stamptype, nfiles, filesize, maxsize, prefix, 0, 0, &sa) ;
+    }
+  }
+  return 0 ;
+}
diff --git a/src/libs6/deps-lib/s6auto b/src/libs6/deps-lib/s6auto
index a9fc8c9..df59808 100644
--- a/src/libs6/deps-lib/s6auto
+++ b/src/libs6/deps-lib/s6auto
@@ -1 +1,5 @@
+s6_auto_write_logger.o
+s6_auto_write_logger_tmp.o
 s6_auto_write_logrun.o
+s6_auto_write_logrun_tmp.o
+s6_auto_write_service.o
diff --git a/src/libs6/s6_auto_write_logger.c b/src/libs6/s6_auto_write_logger.c
new file mode 100644
index 0000000..25c463a
--- /dev/null
+++ b/src/libs6/s6_auto_write_logger.c
@@ -0,0 +1,10 @@
+/* ISC license. */
+
+#include <skalibs/skamisc.h>
+
+#include <s6/auto.h>
+
+void s6_auto_write_logger (char const *dir, char const *loguser, char const *logdir, unsigned int stamptype, unsigned int nfiles, uint64_t filesize, uint64_t maxsize, char const *prefix, char const *service, char const *pipelinename)
+{
+  return s6_auto_write_logger_tmp(dir, loguser, logdir, stamptype, nfiles, filesize, maxsize, prefix, service, pipelinename, &satmp) ;
+}
diff --git a/src/libs6/s6_auto_write_logger_tmp.c b/src/libs6/s6_auto_write_logger_tmp.c
new file mode 100644
index 0000000..03d6aee
--- /dev/null
+++ b/src/libs6/s6_auto_write_logger_tmp.c
@@ -0,0 +1,53 @@
+/* ISC license. */
+
+#include <unistd.h>
+#include <string.h>
+#include <sys/uio.h>
+#include <sys/stat.h>
+
+#include <skalibs/uint64.h>
+#include <skalibs/strerr.h>
+#include <skalibs/stralloc.h>
+#include <skalibs/djbunix.h>
+
+#include <s6/auto.h>
+
+void s6_auto_write_logger_tmp (char const *dir, char const *loguser, char const *logdir, unsigned int stamptype, unsigned int nfiles, uint64_t filesize, uint64_t maxsize, char const *prefix, char const *service, char const *pipelinename, stralloc *sa)
+{
+  mode_t m = umask(0) ;
+  size_t dirlen = strlen(dir) ;
+  char fn[dirlen + 17] ;
+  memcpy(fn, dir, dirlen) ;
+  memcpy(fn + dirlen, "/notification-fd", 17) ;
+  if (mkdir(dir, 0755) == -1) strerr_diefu2sys(111, "mkdir ", dir) ;
+  umask(m) ;
+  m = ~m & 0666 ;
+  if (!openwritenclose_unsafe(fn, "3\n", 2)) goto err ;
+  memcpy(fn + dirlen + 1, "run", 4) ;
+  if (!s6_auto_write_logrun_tmp(fn, loguser, logdir, stamptype, nfiles, filesize, maxsize, prefix, sa)) goto err ;
+  if (service)
+  {
+    struct iovec v[2] = { { .iov_base = (char *)service, .iov_len = strlen(service) }, { .iov_base = "\n", .iov_len = 1 } } ;
+    memcpy(fn + dirlen + 1, "type", 5) ;
+    if (!openwritenclose_unsafe(fn, "longrun\n", 8)) goto err ;
+    memcpy(fn + dirlen + 1, "consumer-for", 13) ;
+    if (!openwritevnclose_unsafe(fn, v, 2)) goto err ;
+    if (pipelinename)
+    {
+      v[0].iov_base = (char *)pipelinename ;
+      v[0].iov_len = strlen(pipelinename) ;
+      memcpy(fn + dirlen + 1, "pipeline-name", 14) ;
+      if (!openwritevnclose_unsafe(fn, v, 2)) goto err ;
+    }
+  }
+  else
+  {
+    if (chmod(fn, m | ((m >> 2) & 0111)) == -1)
+      strerr_diefu2sys(111, "chmod ", fn) ;
+    if (!(m & 0400))
+      strerr_warnw2x("weird umask, check permissions manually on ", fn) ;
+  }
+  return ;
+ err:
+  strerr_diefu2sys(111, "write to ", fn) ;
+}
diff --git a/src/libs6/s6_auto_write_logrun.c b/src/libs6/s6_auto_write_logrun.c
index f5c4baf..d909500 100644
--- a/src/libs6/s6_auto_write_logrun.c
+++ b/src/libs6/s6_auto_write_logrun.c
@@ -1,62 +1,10 @@
 /* ISC license. */
 
-#include <string.h>
-
-#include <skalibs/posixplz.h>
-#include <skalibs/uint64.h>
-#include <skalibs/types.h>
-#include <skalibs/buffer.h>
-#include <skalibs/stralloc.h>
-#include <skalibs/djbunix.h>
 #include <skalibs/skamisc.h>
 
-#include <execline/config.h>
-
-#include <s6/config.h>
 #include <s6/auto.h>
 
-int s6_auto_write_logrun (char const *runfile, char const *loguser, char const *logdir, unsigned int stamptype, unsigned int nfiles, uint64_t filesize, uint64_t maxsize, stralloc *sa)
+int s6_auto_write_logrun (char const *runfile, char const *loguser, char const *logdir, unsigned int stamptype, unsigned int nfiles, uint64_t filesize, uint64_t maxsize, char const *prefix)
 {
-  buffer b ;
-  char buf[1024] ;
-  char fmt[UINT64_FMT] ;
-  int fd = open_trunc(runfile) ;
-  if (fd < 0) return 0 ;
-  buffer_init(&b, &buffer_write, fd, buf, 1024) ;
-  if (buffer_puts(&b, "#!" EXECLINE_SHEBANGPREFIX "execlineb -P\n") < 0) goto err ;
-  if (loguser)
-  {
-    if (buffer_puts(&b, S6_EXTBINPREFIX "s6-setuidgid ") < 0
-     || !string_quote(sa, loguser, strlen(loguser))
-     || buffer_put(&b, sa->s, sa->len) < 0
-     || buffer_put(&b, "\n", 1) < 0) goto err ;
-    sa->len = 0 ;
-  }
-  if (buffer_puts(&b, S6_EXTBINPREFIX "s6-log -bd3 -- ") < 0
-   || (stamptype & 1 && buffer_put(&b, "t ", 2) < 0)
-   || (stamptype & 2 && buffer_put(&b, "T ", 2) < 0)
-   || buffer_put(&b, "n", 1) < 0
-   || buffer_put(&b, fmt, uint_fmt(fmt, nfiles)) < 0
-   || buffer_put(&b, " s", 2) < 0
-   || buffer_put(&b, fmt, uint64_fmt(fmt, filesize)) < 0
-   || buffer_put(&b, " ", 1) < 0) goto err ;
-  if (maxsize)
-  {
-    if (buffer_put(&b, "S", 1) < 0
-     || buffer_put(&b, fmt, uint64_fmt(fmt, maxsize)) < 0
-     || buffer_put(&b, " ", 1) < 0) goto err ;
-  }
-  if (!string_quote(sa, logdir, strlen(logdir))
-   || buffer_put(&b, sa->s, sa->len) < 0
-   || buffer_put(&b, "\n", 1) < 0) goto err ;
-  sa->len = 0 ;
-
-  if (!buffer_flush(&b)) goto err ;
-  fd_close(fd) ;
-  return 1 ;
-
- err:
-  fd_close(fd) ;
-  unlink_void(runfile) ;
-  return 0 ;
+  return s6_auto_write_logrun_tmp(runfile, loguser, logdir, stamptype, nfiles, filesize, maxsize, prefix, &satmp) ;
 }
diff --git a/src/libs6/s6_auto_write_logrun_tmp.c b/src/libs6/s6_auto_write_logrun_tmp.c
new file mode 100644
index 0000000..24163fb
--- /dev/null
+++ b/src/libs6/s6_auto_write_logrun_tmp.c
@@ -0,0 +1,68 @@
+/* ISC license. */
+
+#include <string.h>
+
+#include <skalibs/posixplz.h>
+#include <skalibs/uint64.h>
+#include <skalibs/types.h>
+#include <skalibs/buffer.h>
+#include <skalibs/stralloc.h>
+#include <skalibs/djbunix.h>
+#include <skalibs/skamisc.h>
+
+#include <execline/config.h>
+
+#include <s6/config.h>
+#include <s6/auto.h>
+
+int s6_auto_write_logrun_tmp (char const *runfile, char const *loguser, char const *logdir, unsigned int stamptype, unsigned int nfiles, uint64_t filesize, uint64_t maxsize, char const *prefix, stralloc *sa)
+{
+  buffer b ;
+  char buf[1024] ;
+  char fmt[UINT64_FMT] ;
+  int fd = open_trunc(runfile) ;
+  if (fd < 0) return 0 ;
+  buffer_init(&b, &buffer_write, fd, buf, 1024) ;
+  if (buffer_puts(&b, "#!" EXECLINE_SHEBANGPREFIX "execlineb -P\n") < 0) goto err ;
+  if (loguser)
+  {
+    if (buffer_puts(&b, S6_EXTBINPREFIX "s6-setuidgid ") < 0
+     || !string_quote(sa, loguser, strlen(loguser))
+     || buffer_put(&b, sa->s, sa->len) < 0
+     || buffer_put(&b, "\n", 1) < 0) goto err ;
+    sa->len = 0 ;
+  }
+  if (buffer_puts(&b, S6_EXTBINPREFIX "s6-log -bd3 -- ") < 0
+   || (stamptype & 1 && buffer_put(&b, "t ", 2) < 0)
+   || (stamptype & 2 && buffer_put(&b, "T ", 2) < 0)
+   || buffer_put(&b, "n", 1) < 0
+   || buffer_put(&b, fmt, uint_fmt(fmt, nfiles)) < 0
+   || buffer_put(&b, " s", 2) < 0
+   || buffer_put(&b, fmt, uint64_fmt(fmt, filesize)) < 0
+   || buffer_put(&b, " ", 1) < 0) goto err ;
+  if (maxsize)
+  {
+    if (buffer_put(&b, "S", 1) < 0
+     || buffer_put(&b, fmt, uint64_fmt(fmt, maxsize)) < 0
+     || buffer_put(&b, " ", 1) < 0) goto err ;
+  }
+  if (prefix)
+  {
+    if (buffer_put(&b, "p", 1) < 0
+     || buffer_puts(&b, prefix) < 0
+     || buffer_put(&b, " ", 1) < 0) goto err ;
+  }
+  if (!string_quote(sa, logdir, strlen(logdir))
+   || buffer_put(&b, sa->s, sa->len) < 0
+   || buffer_put(&b, "\n", 1) < 0) goto err ;
+  sa->len = 0 ;
+
+  if (!buffer_flush(&b)) goto err ;
+  fd_close(fd) ;
+  return 1 ;
+
+ err:
+  fd_close(fd) ;
+  unlink_void(runfile) ;
+  return 0 ;
+}
diff --git a/src/libs6/s6_auto_write_service.c b/src/libs6/s6_auto_write_service.c
new file mode 100644
index 0000000..c341a55
--- /dev/null
+++ b/src/libs6/s6_auto_write_service.c
@@ -0,0 +1,59 @@
+/* ISC license. */
+
+#include <string.h>
+#include <unistd.h>
+#include <sys/stat.h>
+#include <sys/uio.h>
+
+#include <skalibs/types.h>
+#include <skalibs/buffer.h>
+#include <skalibs/djbunix.h>
+#include <skalibs/strerr.h>
+
+#include <s6/auto.h>
+
+void s6_auto_write_service (char const *dir, unsigned int nfd, s6_buffer_writer_func_ref f, void *data, char const *logger)
+{
+  int fd ;
+  buffer b ;
+  size_t dirlen = strlen(dir) ;
+  mode_t m = umask(0) ;
+  char buf[4096] ;
+  char fn[dirlen + 17] ;
+  if (mkdir(dir, 0755) == -1) strerr_diefu2sys(111, "mkdir ", dir) ;
+  umask(m) ;
+  m = ~m & 0666 ;
+  memcpy(fn, dir, dirlen) ;
+  memcpy(fn + dirlen, "/run", 5) ;
+  fd = open_trunc(fn) ;
+  if (fd == -1) strerr_diefu2sys(111, "open ", fn) ;
+  buffer_init(&b, &buffer_write, fd, buf, 4096) ;
+  if (!(*f)(&b, data)) strerr_diefu2sys(111, "write to ", fn) ;
+  fd_close(fd) ;
+  if (nfd)
+  {
+    char fmt[UINT_FMT] ;
+    size_t l = uint_fmt(fmt, nfd) ;
+    fmt[l++] = '\n' ;
+    memcpy(fn + dirlen + 1, "notification-fd", 16) ;
+    if (!openwritenclose_unsafe(fn, fmt, l)) strerr_diefu2sys(111, "write to ", fn) ;
+  }
+  if (logger)
+  {
+    memcpy(fn + dirlen + 1, "type", 5) ;
+    if (!openwritenclose_unsafe(fn, "longrun\n", 8)) strerr_diefu2sys(111, "write to ", fn) ;
+    if (logger[0])
+    {
+      struct iovec v[2] = { { .iov_base = (char *)logger, .iov_len = strlen(logger) }, { .iov_base = "\n", .iov_len = 1 } } ;
+      memcpy(fn + dirlen + 1, "producer-for", 13) ;
+      if (!openwritevnclose_unsafe(fn, v, 2)) strerr_diefu2sys(111, "write to ", fn) ;
+    }
+  }
+  else
+  {
+    if (chmod(fn, m | ((m >> 2) & 0111)) < 0)
+      strerr_diefu2sys(111, "chmod ", fn) ;
+    if (!(m & 0400))
+      strerr_warnw2x("weird umask, check permissions manually on ", fn) ;
+  }
+}
diff --git a/src/libs6/s6_servicedir_file_list.c b/src/libs6/s6_servicedir_file_list.c
index bf55d0d..b01a59f 100644
--- a/src/libs6/s6_servicedir_file_list.c
+++ b/src/libs6/s6_servicedir_file_list.c
@@ -12,6 +12,8 @@ static s6_servicedir_desc const s6_servicedir_file_list_[] =
   { .name = "timeout-finish", .type = S6_FILETYPE_UINT, .options = 0 },
   { .name = "max-death-tally", .type = S6_FILETYPE_UINT, .options = 0 },
   { .name = "down-signal", .type = S6_FILETYPE_NORMAL, .options = 0 },
+  { .name = "instance", .type = S6_FILETYPE_DIR, .options = 0 },
+  { .name = "instances", .type = S6_FILETYPE_DIR, .options = 0 },
   { .name = "data", .type = S6_FILETYPE_DIR, .options = 0 },
   { .name = "env", .type = S6_FILETYPE_DIR, .options = 0 },
   { .name = 0, .options = 0 }
diff --git a/src/usertree/s6-usertree-maker.c b/src/usertree/s6-usertree-maker.c
index 3edbd8b..f8740aa 100644
--- a/src/usertree/s6-usertree-maker.c
+++ b/src/usertree/s6-usertree-maker.c
@@ -22,186 +22,139 @@
 #include <s6/config.h>
 #include <s6/auto.h>
 
-#define USAGE "s6-usertree-maker [ -d userscandir ] [ -p path ] [ -E envdir [ -e var ... ] ] [ -r service/logger[/pipeline] ] [ -l loguser ] [ -t stamptype ] [ -n nfiles ] [ -s filesize ] [ -S maxsize ] user logdir dir"
+#define USAGE "s6-usertree-maker [ -d userscandir ] [ -p path ] [ -E envdir [ -e var ... ] ] [ -r service/logger[/pipeline] ] [ -l loguser ] [ -t stamptype ] [ -n nfiles ] [ -s filesize ] [ -S maxsize ] [ -P prefix ] user logdir dir"
 #define dieusage() strerr_dieusage(100, USAGE)
 
 #define VARS_MAX 64
 
-static mode_t mask ;
 static stralloc sa = STRALLOC_ZERO ;
 
-static inline void write_run (char const *runfile, char const *user, char const *sc, char const *path, char const *userenvdir, char const *const *vars, size_t varlen)
+typedef struct svinfo_s svinfo, *svinfo_ref ;
+struct svinfo_s
 {
-  buffer b ;
-  char buf[2048] ;
-  int fd = open_trunc(runfile) ;
-  if (fd < 0) strerr_diefu3sys(111, "open ", runfile, " for writing") ;
-  buffer_init(&b, &buffer_write, fd, buf, 2048) ;
-  if (!string_quote(&sa, user, strlen(user))) goto errq ;
-  if (buffer_puts(&b, "#!" EXECLINE_SHEBANGPREFIX "execlineb -P\n"
+  char const *user ;
+  char const *sc ;
+  char const *logger ;
+  char const *path ;
+  char const *userenvdir ;
+  char const **vars ;
+  size_t varlen ;
+} ;
+
+static int write_run (buffer *b, void *data)
+{
+  svinfo *t = data ;
+  if (!string_quote(&sa, t->user, strlen(t->user))) return 0 ;
+  if (buffer_puts(b, "#!" EXECLINE_SHEBANGPREFIX "execlineb -P\n"
     EXECLINE_EXTBINPREFIX "fdmove -c 2 1\n"
     EXECLINE_EXTBINPREFIX "emptyenv -p\n"
     EXECLINE_EXTBINPREFIX "export USER ") < 0
-   || buffer_put(&b, sa.s, sa.len) < 0
-   || buffer_puts(&b, "\n"
+   || buffer_put(b, sa.s, sa.len) < 0
+   || buffer_puts(b, "\n"
     S6_EXTBINPREFIX "s6-envuidgid -i -- ") < 0
-   || buffer_put(&b, sa.s, sa.len) < 0
-   || buffer_puts(&b, "\n"
+   || buffer_put(b, sa.s, sa.len) < 0
+   || buffer_puts(b, "\n"
     S6_EXTBINPREFIX "s6-applyuidgid -U --\n"
     EXECLINE_EXTBINPREFIX "backtick -in HOME { "
     EXECLINE_EXTBINPREFIX "homeof ") < 0
-   || buffer_put(&b, sa.s, sa.len) < 0
-   || buffer_put(&b, " }\n", 3) < 0) goto err ;
+   || buffer_put(b, sa.s, sa.len) < 0
+   || buffer_put(b, " }\n", 3) < 0) goto err ;
   sa.len = 0 ;
-  if (userenvdir)
+  if (t->userenvdir)
   {
-    if (!string_quote(&sa, userenvdir, strlen(userenvdir))) goto errq ;
-    if (buffer_puts(&b, S6_EXTBINPREFIX "s6-envdir -i -- ") < 0
-     || buffer_put(&b, sa.s, sa.len) < 0
-     || buffer_put(&b, "\n", 1) < 0) goto err ;
+    if (!string_quote(&sa, t->userenvdir, strlen(t->userenvdir))) return 0 ;
+    if (buffer_puts(b, S6_EXTBINPREFIX "s6-envdir -i -- ") < 0
+     || buffer_put(b, sa.s, sa.len) < 0
+     || buffer_put(b, "\n", 1) < 0) goto err ;
     sa.len = 0 ;
-    if (varlen)
+    if (t->varlen)
     {
-      if (buffer_puts(&b, EXECLINE_EXTBINPREFIX "multisubstitute\n{\n") < 0) goto err ;
-      for (size_t i = 0 ; i < varlen ; i++)
+      if (buffer_puts(b, EXECLINE_EXTBINPREFIX "multisubstitute\n{\n") < 0) return 0 ;
+      for (size_t i = 0 ; i < t->varlen ; i++)
       {
-        if (!string_quote(&sa, vars[i], strlen(vars[i]))) goto errq ;
-        if (buffer_puts(&b, "  importas -D \"\" -- ") < 0
-         || buffer_put(&b, sa.s, sa.len) < 0
-         || buffer_put(&b, " ", 1) < 0
-         || buffer_put(&b, sa.s, sa.len) < 0
-         || buffer_put(&b, "\n", 1) < 0) goto err ;
+        if (!string_quote(&sa, t->vars[i], strlen(t->vars[i]))) return 0 ;
+        if (buffer_puts(b, "  importas -D \"\" -- ") < 0
+         || buffer_put(b, sa.s, sa.len) < 0
+         || buffer_put(b, " ", 1) < 0
+         || buffer_put(b, sa.s, sa.len) < 0
+         || buffer_put(b, "\n", 1) < 0) goto err ;
         sa.len = 0 ;
       }
-      if (buffer_put(&b, "}\n", 2) < 0) goto err ;
+      if (buffer_put(b, "}\n", 2) < 0) return 0 ;
     }
   }
-  if (buffer_puts(&b, EXECLINE_EXTBINPREFIX "multisubstitute\n{\n"
+  if (buffer_puts(b, EXECLINE_EXTBINPREFIX "multisubstitute\n{\n"
    "  importas -i USER USER\n"
    "  importas -i HOME HOME\n"
    "  importas -i UID UID\n"
    "  importas -i GID GID\n"
-   "  importas -i GIDLIST GIDLIST\n}\n") < 0) goto err ;
-  if (userenvdir && varlen)
+   "  importas -i GIDLIST GIDLIST\n}\n") < 0) return 0 ;
+  if (t->userenvdir && t->varlen)
   {
-    for (size_t i = 0 ; i < varlen ; i++)
+    for (size_t i = 0 ; i < t->varlen ; i++)
     {
-      if (!string_quote(&sa, vars[i], strlen(vars[i]))) goto errq ;
-      if (buffer_puts(&b, EXECLINE_EXTBINPREFIX "export ") < 0
-       || buffer_put(&b, sa.s, sa.len) < 0
-       || buffer_put(&b, " ${", 3) < 0
-       || buffer_put(&b, sa.s, sa.len) < 0
-       || buffer_put(&b, "}\n", 2) < 0) goto err ;
+      if (!string_quote(&sa, t->vars[i], strlen(t->vars[i]))) return 0 ;
+      if (buffer_puts(b, EXECLINE_EXTBINPREFIX "export ") < 0
+       || buffer_put(b, sa.s, sa.len) < 0
+       || buffer_put(b, " ${", 3) < 0
+       || buffer_put(b, sa.s, sa.len) < 0
+       || buffer_put(b, "}\n", 2) < 0) goto err ;
       sa.len = 0 ;
     }
   }
-  if (!string_quote(&sa, path, strlen(path))) goto errq ;
-  if (buffer_puts(&b, EXECLINE_EXTBINPREFIX "export PATH ") < 0
-   || buffer_put(&b, sa.s, sa.len) < 0) goto err ;
+  if (!string_quote(&sa, t->path, strlen(t->path))) return 0 ;
+  if (buffer_puts(b, EXECLINE_EXTBINPREFIX "export PATH ") < 0
+   || buffer_put(b, sa.s, sa.len) < 0) goto err ;
   sa.len = 0 ;
-  if (!string_quote(&sa, sc, strlen(sc))) goto errq ;
-  if (buffer_puts(&b, "\n"
+  if (!string_quote(&sa, t->sc, strlen(t->sc))) return 0 ;
+  if (buffer_puts(b, "\n"
     S6_EXTBINPREFIX "s6-svscan -d3 -- ") < 0
-   || buffer_put(&b, sa.s, sa.len) < 0) goto err ;
+   || buffer_put(b, sa.s, sa.len) < 0) goto err ;
   sa.len = 0 ;
-  if (!buffer_putflush(&b, "\n", 1)) goto err ;
-  fd_close(fd) ;
-  return ;
- err:
-  strerr_diefu2sys(111, "write to ", runfile) ;
- errq:
-  strerr_diefu1sys(111, "quote string") ;
-}
+  if (!buffer_putflush(b, "\n", 1)) return 0 ;
+  return 1 ;
 
-static void write_service (char const *dir, char const *user, char const *sc, char const *logger, char const *path, char const *userenvdir, char const *const *vars, size_t varlen)
-{
-  size_t dirlen = strlen(dir) ;
-  char fn[dirlen + 17] ;
-  memcpy(fn, dir, dirlen) ;
-  memcpy(fn + dirlen, "/notification-fd", 17) ;
-  if (!openwritenclose_unsafe(fn, "3\n", 2)) strerr_diefu2sys(111, "write to ", fn) ;
-  memcpy(fn + dirlen + 1, "run", 4) ;
-  write_run(fn, user, sc, path, userenvdir, vars, varlen) ;
-  if (logger)
-  {
-    struct iovec v[2] = { { .iov_base = (char *)logger, .iov_len = strlen(logger) }, { .iov_base = "\n", .iov_len = 1 } } ;
-    memcpy(fn + dirlen + 1, "type", 5) ;
-    if (!openwritenclose_unsafe(fn, "longrun\n", 8)) strerr_diefu2sys(111, "write to ", fn) ;
-    memcpy(fn + dirlen + 1, "producer-for", 13) ;
-    if (!openwritevnclose_unsafe(fn, v, 2)) strerr_diefu2sys(111, "write to ", fn) ;
-  }
-  else
-  {
-    if (chmod(fn, mask | ((mask >> 2) & 0111)) < 0)
-      strerr_diefu2sys(111, "chmod ", fn) ;
-  }
-}
-
-static void write_logger (char const *dir, char const *user, char const *logdir, unsigned int stamptype, unsigned int nfiles, uint64_t filesize, uint64_t maxsize, char const *service, char const *pipelinename)
-{
-  size_t dirlen = strlen(dir) ;
-  char fn[dirlen + 17] ;
-  memcpy(fn, dir, dirlen) ;
-  memcpy(fn + dirlen, "/notification-fd", 17) ;
-  if (!openwritenclose_unsafe(fn, "3\n", 2)) goto err ;
-  memcpy(fn + dirlen + 1, "run", 4) ;
-  if (!s6_auto_write_logrun(fn, user, logdir, stamptype, nfiles, filesize, maxsize, &sa)) goto err ;
-  if (service)
-  {
-    struct iovec v[2] = { { .iov_base = (char *)service, .iov_len = strlen(service) }, { .iov_base = "\n", .iov_len = 1 } } ;
-    memcpy(fn + dirlen + 1, "type", 5) ;
-    if (!openwritenclose_unsafe(fn, "longrun\n", 8)) goto err ;
-    memcpy(fn + dirlen + 1, "consumer-for", 13) ;
-    if (!openwritevnclose_unsafe(fn, v, 2)) goto err ;
-    if (pipelinename)
-    {
-      v[0].iov_base = (char *)pipelinename ;
-      v[0].iov_len = strlen(pipelinename) ;
-      memcpy(fn + dirlen + 1, "pipeline-name", 14) ;
-      if (!openwritevnclose_unsafe(fn, v, 2)) goto err ;
-    }
-  }
-  else
-  {
-    if (chmod(fn, mask | ((mask >> 2) & 0111)) < 0)
-      strerr_diefu2sys(111, "chmod ", fn) ;
-  }
-  return ;
  err:
-  strerr_diefu2sys(111, "write to ", fn) ;
+  sa.len = 0 ;
+  return 0 ;
 }
 
 int main (int argc, char *const *argv)
 {
-  char const *userscandir = "${HOME}/service" ;
-  char const *path = SKALIBS_DEFAULTPATH ;
-  char const *userenvdir = 0 ;
+  char const *vars[VARS_MAX] ;
+  svinfo t =
+  {
+    .sc = "${HOME}/service",
+    .logger = 0,
+    .path = SKALIBS_DEFAULTPATH,
+    .userenvdir = 0,
+    .vars = vars,
+    .varlen = 0
+  } ;
   char *rcinfo[3] = { 0, 0, 0 } ;
   char const *loguser = 0 ;
   unsigned int stamptype = 1 ;
   unsigned int nfiles = 10 ;
   uint64_t filesize = 1000000 ;
   uint64_t maxsize = 0 ;
+  char const *prefix = 0 ;
   size_t dirlen ;
-  size_t varlen = 0 ;
-  mode_t m ;
-  char const *vars[VARS_MAX] ;
   PROG = "s6-usertree-maker" ;
   {
     subgetopt l = SUBGETOPT_ZERO ;
     for (;;)
     {
-      int opt = subgetopt_r(argc, (char const *const *)argv, "d:p:E:e:r:l:t:n:s:S:", &l) ;
+      int opt = subgetopt_r(argc, (char const *const *)argv, "d:p:E:e:r:l:t:n:s:S:P:", &l) ;
       if (opt == -1) break ;
       switch (opt)
       {
-        case 'd' : userscandir = l.arg ; break ;
-        case 'p' : path = l.arg ; break ;
-        case 'E' : userenvdir = l.arg ; break ;
+        case 'd' : t.sc = l.arg ; break ;
+        case 'p' : t.path = l.arg ; break ;
+        case 'E' : t.userenvdir = l.arg ; break ;
         case 'e' :
-          if (varlen >= VARS_MAX) strerr_dief1x(100, "too many -v variables") ;
+          if (t.varlen >= VARS_MAX) strerr_dief1x(100, "too many -v variables") ;
           if (strchr(l.arg, '=')) strerr_dief2x(100, "invalid variable name: ", l.arg) ;
-          vars[varlen++] = l.arg ;
+          t.vars[t.varlen++] = l.arg ;
           break ;
         case 'r' : rcinfo[0] = (char *)l.arg ; break ;
         case 'l' : loguser = l.arg ; break ;
@@ -209,6 +162,7 @@ int main (int argc, char *const *argv)
         case 'n' : if (!uint0_scan(l.arg, &nfiles)) dieusage() ; break ;
         case 's' : if (!uint640_scan(l.arg, &filesize)) dieusage() ; break ;
         case 'S' : if (!uint640_scan(l.arg, &maxsize)) dieusage() ; break ;
+        case 'P' : prefix = l.arg ; break ;
         default : dieusage() ;
       }
     }
@@ -216,7 +170,7 @@ int main (int argc, char *const *argv)
   }
   if (argc < 3) dieusage() ;
   if (argv[1][0] != '/') strerr_dief1x(100, "logdir must be absolute") ;
-  if (userscandir[0] != '/' && !str_start(userscandir, "${HOME}/"))
+  if (t.sc[0] != '/' && !str_start(t.sc, "${HOME}/"))
     strerr_dief1x(100, "userscandir must be absolute or start with ${HOME}/") ;
   if (stamptype > 3) strerr_dief1x(100, "stamptype must be 0, 1, 2 or 3") ;
   if (rcinfo[0])
@@ -239,8 +193,7 @@ int main (int argc, char *const *argv)
       if (strchr(rcinfo[2], '/')) strerr_dief2x(100, "slashes", " are forbidden in s6-rc names") ;
     }
   }
-  m = umask(0) ;
-  mask = ~m & 0666 ;
+  t.user = argv[0] ;
   dirlen = strlen(argv[2]) ;
 
   if (rcinfo[0])
@@ -252,25 +205,19 @@ int main (int argc, char *const *argv)
     dir[dirlen] = '/' ;
     if (mkdir(argv[2], 0755) < 0 && errno != EEXIST)
       strerr_diefu2sys(111, "mkdir ", argv[2]) ;
+    t.logger = rcinfo[1] ;
     memcpy(dir + dirlen + 1, rcinfo[0], svclen + 1) ;
-    if (mkdir(dir, 0755) < 0) strerr_diefu2sys(111, "mkdir ", dir) ;
+    s6_auto_write_service(dir, 3, &write_run, &t, rcinfo[1]) ;
     memcpy(dir + dirlen + 1, rcinfo[1], loglen + 1) ;
-    if (mkdir(dir, 0755) < 0) strerr_diefu2sys(111, "mkdir ", dir) ;
-    umask(m) ;
-    write_logger(dir, loguser, argv[1], stamptype, nfiles, filesize, maxsize, rcinfo[0], rcinfo[2]) ;
-    memcpy(dir + dirlen + 1, rcinfo[0], svclen + 1) ;
-    write_service(dir, argv[0], userscandir, rcinfo[1], path, userenvdir, vars, varlen) ;
+    s6_auto_write_logger_tmp(dir, loguser, argv[1], stamptype, nfiles, filesize, maxsize, prefix, rcinfo[0], rcinfo[2], &sa) ;
   }
   else
   {
     char dir[dirlen + 5] ;
     memcpy(dir, argv[2], dirlen) ;
     memcpy(dir + dirlen, "/log", 5) ;
-    if (mkdir(argv[2], 0755) < 0) strerr_diefu2sys(111, "mkdir ", argv[2]) ;
-    if (mkdir(dir, 0755) < 0) strerr_diefu2sys(111, "mkdir ", argv[2]) ;
-    umask(m) ;
-    write_service(argv[2], argv[0], userscandir, 0, path, userenvdir, vars, varlen) ;
-    write_logger(dir, loguser, argv[1], stamptype, nfiles, filesize, maxsize, 0, 0) ;
+    s6_auto_write_service(argv[2], 3, &write_run, &t, 0) ;
+    s6_auto_write_logger_tmp(dir, loguser, argv[1], stamptype, nfiles, filesize, maxsize, prefix, 0, 0, &sa) ;
   }
   return 0 ;
 }