Add -d notif to s6-svscan; this is only shallow readiness.

5 files changed, 49 insertions, 5 deletions

diff --git a/NEWS b/NEWS
index 6956ff7..1996769 100644
--- a/NEWS
+++ b/NEWS
@@ -1,5 +1,15 @@
 Changelog for s6.
 
+In 2.7.2.0
+----------
+
+ - s6-ipcserver-socketbinder now takes a -B option to make the socket blocking.
+ - s6-svscan now takes a "-d notif" option to notify readiness. This is
+*shallow readiness*, i.e. readiness will be reported when s6-svscan is ready
+to receive s6-svscanctl commands; it does *not* mean all the services started
+at s6-svscan launch will be ready.
+
+
 In 2.7.1.1
 ----------
 
diff --git a/doc/s6-svscan.html b/doc/s6-svscan.html
index 4bb943b..665fd75 100644
--- a/doc/s6-svscan.html
+++ b/doc/s6-svscan.html
@@ -27,7 +27,7 @@ the root or a branch of a <em>supervision tree</em>.
 <h2> Interface </h2>
 
 <pre>
-     s6-svscan [ -S | -s ] [ -c max ] [ -t <em>rescan</em> ] [ <em>scandir</em> ]
+     s6-svscan [ -S | -s ] [ -d <em>notif</em> ] [ -c max ] [ -t <em>rescan</em> ] [ <em>scandir</em> ]
 </pre>
 
 <ul>
@@ -62,6 +62,17 @@ execution. </li>
  <li> <tt>-S&nbsp;</tt>&nbsp;: do not divert signals. This is the default for now;
 it may change in a future version of s6. </li>
  <li> <tt>-s&nbsp;</tt>&nbsp;: divert signals - see below. </li>
+ <li> <tt>-d&nbsp;<em>notif</em></tt>&nbsp;: notify readiness on file descriptor
+<em>notif</em>. When s6-svscan is ready to accept commands from
+<a href="s6-svscanctl.html">s6-svscanctl</a>, it will write a newline to <em>notif</em>.
+<em>notif</em> cannot be lesser than 3. By default, no notification is sent. Please
+note that using this option signals <em>shallow readiness</em>: s6-svscan being
+"ready" only means that it is ready to accept commands. It <em>does not mean</em>
+that all the services it launches at start are themselves ready, or even started, or
+even that the relevant <a href="s6-supervise.html">s6-supervise</a> processes have
+been started. If you need to test for <em>deep readiness</em>, meaning that all the
+services in the supervision tree have been started and are ready, you cannot rely
+on this option. </li>
  <li> <tt>-c&nbsp;<em>max</em></tt>&nbsp;: maintain services for up to <em>max</em>
 service directories. Default is 500. Lower limit is 2. There is no upper limit, but:
  <ul>
diff --git a/doc/upgrade.html b/doc/upgrade.html
index 3e2a538..4ea789c 100644
--- a/doc/upgrade.html
+++ b/doc/upgrade.html
@@ -18,6 +18,15 @@
 
 <h1> What has changed in s6 </h1>
 
+<h2> in 2.7.2.0 </h2>
+
+<ul>
+ <li> <tt>-B</tt> option added to
+<a href="s6-ipcserver-socketbinder.html">s6-ipcserver-socketbinder</a>. </li>
+ <li> <tt>-d&nbsp;<em>notif</em></tt> option added to
+<a href="s6-svscan.html">s6-svscan</a>. </li>
+</ul>
+
 <h2> in 2.7.1.1 </h2>
 
 <ul>
diff --git a/package/info b/package/info
index 7f8c4ef..17042af 100644
--- a/package/info
+++ b/package/info
@@ -1,4 +1,4 @@
 package=s6
-version=2.7.1.1
+version=2.7.2.0
 category=admin
 package_macro_name=S6
diff --git a/src/supervision/s6-svscan.c b/src/supervision/s6-svscan.c
index 497970e..0d06bac 100644
--- a/src/supervision/s6-svscan.c
+++ b/src/supervision/s6-svscan.c
@@ -5,6 +5,7 @@
 #include <sys/wait.h>
 #include <unistd.h>
 #include <errno.h>
+#include <fcntl.h>
 #include <signal.h>
 #include <skalibs/allreadwrite.h>
 #include <skalibs/sgetopt.h>
@@ -20,7 +21,8 @@
 #include <s6/config.h>
 #include <s6/s6-supervise.h>
 
-#define USAGE "s6-svscan [ -S | -s ] [ -c maxservices ] [ -t timeout ] [ dir ]"
+#define USAGE "s6-svscan [ -S | -s ] [ -c maxservices ] [ -t timeout ] [ -d notif ] [ dir ]"
+#define dieusage() strerr_dieusage(100, USAGE)
 
 #define FINISH_PROG S6_SVSCAN_CTLDIR "/finish"
 #define CRASH_PROG S6_SVSCAN_CTLDIR "/crash"
@@ -448,13 +450,14 @@ int main (int argc, char const *const *argv)
 {
   iopause_fd x[2] = { { -1, IOPAUSE_READ, 0 }, { -1, IOPAUSE_READ, 0 } } ;
   int divertsignals = 0 ;
+  unsigned int notif = 0 ;
   PROG = "s6-svscan" ;
   {
     subgetopt_t l = SUBGETOPT_ZERO ;
     unsigned int t = 0 ;
     for (;;)
     {
-      int opt = subgetopt_r(argc, argv, "Sst:c:", &l) ;
+      int opt = subgetopt_r(argc, argv, "Sst:c:d:", &l) ;
       if (opt == -1) break ;
       switch (opt)
       {
@@ -462,7 +465,12 @@ int main (int argc, char const *const *argv)
         case 's' : divertsignals = 1 ; break ;
         case 't' : if (uint0_scan(l.arg, &t)) break ;
         case 'c' : if (uint0_scan(l.arg, &max)) break ;
-        default : strerr_dieusage(100, USAGE) ;
+        case 'd' :
+          if (!uint0_scan(l.arg, &notif)) dieusage() ;
+          if (notif < 3) strerr_dief1x(100, "notification fd must be 3 or more") ;
+          if (fcntl(notif, F_GETFD) < 0) strerr_dief1sys(100, "invalid notification fd") ;
+          break ;
+        default : dieusage() ;
       }
     }
     argc -= l.ind ; argv += l.ind ;
@@ -501,6 +509,12 @@ int main (int argc, char const *const *argv)
     if (selfpipe_trapset(&set) < 0) strerr_diefu1sys(111, "trap signals") ;
   }
 
+  if (notif)
+  {
+    fd_write(notif, "\n", 1) ;
+    fd_close(notif) ;
+    notif = 0 ;
+  }
 
   {
     struct svinfo_s blob[max] ; /* careful with that stack, Eugene */