[shepherd] 27/32: service: 'make-inetd-constructor' lets the caller specify socket ownership.

[Ludovic Courtès]

civodul pushed a commit to branch master
in repository shepherd.

commit 723319a689c09e5b9d67dd4427b35333770529f2
Author: Ludovic Courtès <ludo@gnu.org>
AuthorDate: Mon Mar 28 21:48:01 2022 +0200

    service: 'make-inetd-constructor' lets the caller specify socket ownership.
    
    * modules/shepherd/service.scm (make-inetd-constructor): Add
     #:socket-owner, #:socket-group, and #:socket-directory-permissions
     parameters.  Honor them.
    * doc/shepherd.texi (Service De- and Constructors): Document it.
---
 doc/shepherd.texi            |  8 ++++++++
 modules/shepherd/service.scm | 28 +++++++++++++++++++++++++---
 2 files changed, 33 insertions(+), 3 deletions(-)

diff --git a/doc/shepherd.texi b/doc/shepherd.texi
index d764970..4867ceb 100644
--- a/doc/shepherd.texi
+++ b/doc/shepherd.texi
@@ -1068,6 +1068,8 @@ in charge of listening.
 @deffn {procedure} make-inetd-constructor @var{command} @var{address}
   [#:service-name-stem _] [#:requirements '()] @
   [#:socket-style SOCK_STREAM] [#:listen-backlog 10] @
+  [#:socket-owner (getuid)] [#:socket-group (getgid)] @
+  [#:socket-directory-permissions #o755] @
   [#:max-connections (default-inetd-max-connections)] @
   [#:user #f] @
   [#:group #f] @
@@ -1079,6 +1081,12 @@ in charge of listening.
 Return a procedure that opens a socket listening to @var{address}, an
 object as returned by @code{make-socket-address}, and accepting connections in
 the background; the @var{listen-backlog} argument is passed to @var{accept}.
+
+When @var{address} is of type @code{AF_UNIX}, @var{socket-owner} and
+@var{socket-group} are strings or integers that specify its ownership and that
+of its parent directory; @var{socket-directory-permissions} specifies the
+permissions for its parent directory.
+
 Upon a client connection, a transient service running @var{command} is
 spawned.  Only up to @var{max-connections} simultaneous connections are
 accepted; when that threshold is reached, new connections are immediately
diff --git a/modules/shepherd/service.scm b/modules/shepherd/service.scm
index e0bc444..d0d6159 100644
--- a/modules/shepherd/service.scm
+++ b/modules/shepherd/service.scm
@@ -1309,6 +1309,9 @@ as argument, where SIGNAL defaults to `SIGTERM'."
                                      (basename program))))
                                  (requirements '())
                                  (socket-style SOCK_STREAM)
+                                 (socket-owner (getuid))
+                                 (socket-group (getgid))
+                                 (socket-directory-permissions #o755)
                                  (listen-backlog 10)
                                  (max-connections
                                   (default-inetd-max-connections))
@@ -1324,6 +1327,12 @@ as argument, where SIGNAL defaults to `SIGTERM'."
   "Return a procedure that opens a socket listening to @var{address}, an
 object as returned by @code{make-socket-address}, and accepting connections in
 the background; the @var{listen-backlog} argument is passed to @var{accept}.
+
+When @var{address} is of type @code{AF_UNIX}, @var{socket-owner} and
+@var{socket-group} are strings or integers that specify its ownership and that
+of its parent directory; @var{socket-directory-permissions} specifies the
+permissions for its parent directory.
+
 Upon a client connection, a transient service running @var{command} is
 spawned.  Only up to @var{max-connections} simultaneous connections are
 accepted; when that threshold is reached, new connections are immediately
@@ -1378,13 +1387,26 @@ The remaining arguments are as for 
@code{make-forkexec-constructor}."
       (start service)))
 
   (lambda args
-    (let ((sock (non-blocking-port
-                 (socket (sockaddr:fam address) socket-style 0))))
+    (let ((sock  (non-blocking-port
+                  (socket (sockaddr:fam address) socket-style 0)))
+          (owner (if (integer? socket-owner)
+                     socket-owner
+                     (passwd:uid (getpwnam socket-owner))))
+          (group (if (integer? socket-group)
+                     socket-group
+                     (group:gid (getgrnam socket-group)))))
       (setsockopt sock SOL_SOCKET SO_REUSEADDR 1)
+
       (when (= AF_UNIX (sockaddr:fam address))
-        (mkdir-p (dirname (sockaddr:path address)))
+        (mkdir-p (dirname (sockaddr:path address))
+                 socket-directory-permissions)
+        (chown (dirname (sockaddr:path address)) owner group)
         (catch-system-error (delete-file (sockaddr:path address))))
       (bind sock address)
+      (when (= AF_UNIX (sockaddr:fam address))
+        (chown sock owner group)
+        (chmod sock #o666))
+
       (listen sock listen-backlog)
       (spawn-fiber
        (lambda ()