Fix a race condition in s6rc_servicedir_manage()

6 files changed, 42 insertions, 14 deletions

diff --git a/INSTALL b/INSTALL
index ee9ea24..1718257 100644
--- a/INSTALL
+++ b/INSTALL
@@ -8,7 +8,7 @@ Build Instructions
   - GNU make version 3.81 or later
   - skalibs version 2.5.1.1 or later: http://skarnet.org/software/skalibs/
   - execline version 2.3.0.1 or later: http://skarnet.org/software/execline/
-  - s6 version 2.6.0.0 or later: http://skarnet.org/software/s6/
+  - s6 version 2.6.0.1 or later: http://skarnet.org/software/s6/
 
  This software will run on any operating system that implements
 POSIX.1-2008, available at:
diff --git a/NEWS b/NEWS
index f8a0d08..b7d19fc 100644
--- a/NEWS
+++ b/NEWS
@@ -1,5 +1,11 @@
 Changelog for s6-rc.
 
+In 0.2.1.2
+----------
+
+ - Bugfix release.
+
+
 In 0.2.1.1
 ----------
 
diff --git a/doc/index.html b/doc/index.html
index 5fb12d1..52759fa 100644
--- a/doc/index.html
+++ b/doc/index.html
@@ -52,7 +52,7 @@ scripts are also run in a controlled environment.
  <li> <a href="//skarnet.org/software/execline/">execline</a> version
 2.3.0.1 or later </li>
  <li> <a href="//skarnet.org/software/s6/">s6</a> version
-2.6.0.0 or later </li>
+2.6.0.1 or later </li>
 </ul>
 
 <h3> Licensing </h3>
@@ -66,7 +66,7 @@ scripts are also run in a controlled environment.
 
 <ul>
  <li> The current released version of s6-rc is
-<a href="s6-rc-0.2.1.1.tar.gz">0.2.1.1</a>. </li>
+<a href="s6-rc-0.2.1.2.tar.gz">0.2.1.2</a>. </li>
  <li> Alternatively, you can checkout a copy of the
 <a href="//git.skarnet.org/cgi-bin/cgit.cgi/s6-rc/">s6-rc
 git repository</a>:
diff --git a/doc/upgrade.html b/doc/upgrade.html
index 7ff579f..c5e944a 100644
--- a/doc/upgrade.html
+++ b/doc/upgrade.html
@@ -18,6 +18,13 @@
 
 <h1> What has changed in s6-rc </h1>
 
+<h2> in 0.2.1.2 </h2>
+
+<ul>
+ <li> <a href="//skarnet.org/software/s6/">s6</a>
+dependency bumped to 2.6.0.1. </li>
+</ul>
+
 <h2> in 0.2.1.1 </h2>
 
 <ul>
diff --git a/package/info b/package/info
index 42b0037..be6dde5 100644
--- a/package/info
+++ b/package/info
@@ -1,4 +1,4 @@
 package=s6-rc
-version=0.2.1.1
+version=0.2.1.2
 category=admin
 package_macro_name=S6RC
diff --git a/src/libs6rc/s6rc_servicedir_manage.c b/src/libs6rc/s6rc_servicedir_manage.c
index 529067b..218c0af 100644
--- a/src/libs6rc/s6rc_servicedir_manage.c
+++ b/src/libs6rc/s6rc_servicedir_manage.c
@@ -48,6 +48,7 @@ int s6rc_servicedir_manage (char const *live, tain_t const *deadline, tain_t *st
     if (d->d_name[0] == '.') continue ;
     {
       size_t len = strlen(d->d_name) ;
+      int fdlock ;
       int r ;
       uint16_t id ;
       char srcfn[livelen + 20 + len] ;
@@ -55,25 +56,29 @@ int s6rc_servicedir_manage (char const *live, tain_t const *deadline, tain_t *st
       memcpy(srcfn, dirfn, livelen + 12) ;
       srcfn[livelen + 12] = '/' ;
       memcpy(srcfn + livelen + 13, d->d_name, len + 1) ;
+      fdlock = s6_svc_lock_take(srcfn) ;
+      if (fdlock < 0) goto err ;
       r = s6_svc_ok(srcfn) ;
-      if (r < 0) { e = errno ; goto err ; }
+      if (r < 0) goto errinloop ;
       if (!r)
       {
         memcpy(srcfn + livelen + 13 + len, "/down", 6) ;
-        if (!touch(srcfn)) { e = errno ; goto err ; }
+        if (!touch(srcfn)) goto errinloop ;
         memcpy(srcfn + livelen + 14 + len, "event", 6) ;
-        if (!ftrigw_fifodir_make(srcfn, gid, 0)) { e = errno ; goto err ; }
+        if (!ftrigw_fifodir_make(srcfn, gid, 0)) goto errinloop ;
         id = ftrigr_subscribe(&a, srcfn, "s", 0, deadline, stamp) ;
-        if (!id) { e = errno ; goto err ; }
-        if (!genalloc_append(uint16_t, &ids, &id)) { e = errno ; goto err ; }
+        if (!id) goto errinloop ;
+        s6_svc_lock_release(fdlock) ;
+        if (!genalloc_append(uint16_t, &ids, &id)) goto err ;
         srcfn[livelen + 13 + len] = 0 ;
       }
+      else s6_svc_lock_release(fdlock) ;
       memcpy(dstfn, live, livelen) ;
       memcpy(dstfn + livelen, "/scandir/", 9) ;
       memcpy(dstfn + livelen + 9, d->d_name, len + 1) ;
       if (symlink(srcfn, dstfn) < 0)
       {
-        if (!r || errno != EEXIST) { e = errno ; goto err ; }
+        if (!r || errno != EEXIST) goto err ;
       }
       else if (!r)
       {
@@ -81,12 +86,17 @@ int s6rc_servicedir_manage (char const *live, tain_t const *deadline, tain_t *st
         {
           e = errno ;
           s6rc_servicedir_unsupervise(live, d->d_name, 0) ;
-          goto err ;
+          goto errn ;
         }
       }
+      continue ;
+     errinloop:
+      e = errno ;
+      s6_svc_lock_release(fdlock) ;
+      goto errn ;
     }
   }
-  if (errno) { e = errno ; goto err ; }
+  if (errno) goto err ;
   dir_close(dir) ;
   {
     char scanfn[livelen + 9] ;
@@ -94,10 +104,10 @@ int s6rc_servicedir_manage (char const *live, tain_t const *deadline, tain_t *st
     memcpy(scanfn, live, livelen) ;
     memcpy(scanfn + livelen, "/scandir", 9) ;
     r = s6_svc_writectl(scanfn, S6_SVSCAN_CTLDIR, "a", 1) ;
-    if (r < 0) { e = errno ; goto closederr ; }
+    if (r < 0) goto closederr ;
     if (!r) ok = 3 ;
     else if (ftrigr_wait_and(&a, genalloc_s(uint16_t, &ids), genalloc_len(uint16_t, &ids), deadline, stamp) < 0)
-    { e = errno ; goto closederr ; }
+      goto closederr ;
   }
 
   ftrigr_end(&a) ;
@@ -106,8 +116,13 @@ int s6rc_servicedir_manage (char const *live, tain_t const *deadline, tain_t *st
   return ok ;
 
  err:
+  e = errno ;
+ errn:
   dir_close(dir) ;
+  goto closederrn ;
  closederr:
+  e = errno ;
+ closederrn:
   ftrigr_end(&a) ;
   genalloc_free(uint16_t, &ids) ;
   rollback(live, newnames.s, newnames.len) ;