rpcbind: systemd socket activation

From: Tom Gundersen <[email protected]>

Making rpcbind sockect activated will greatly simplify its integration in systemd systems. In essence, other services may now assume that rpcbind is always available, even during very early boot. This means that we no longer need to worry about any ordering dependencies.

This is based on a patch originally posted by Lennart Poettering:
<http://permalink.gmane.org/gmane.linux.nfs/33774>.

That patch was not merged due to the lack of a shared library and as systemd was seen to be too Fedora specific.

Systemd now provides a shared library, and it is (or very soon will be) the default init system on all the major Linux distributions.

This version of the patch has three changes from the original:

* It uses the shared library.
* It comes with unit files.
* It is rebased on top of master.

Please review the patch with "git show -b" or otherwise ignoring the whitespace changes, or it will be extremely difficult to read.

v4: reorganized the changes to make the diff easier to read
remove systemd scripts.

v3: rebase
fix typos
listen on /run/rpcbind.sock, rather than /var/run/rpcbind.sock (the latter is a symlink to the former, but this means the socket can be created before /var is mounted)
NB: this version has been compile-tested only as I no longer use rpcbind myself
v2: correctly enable systemd code at compile time
handle the case where not all the required sockets were supplied listen on udp/tcp port 111 in addition to /var/run/rpcbind.sock do not daemonize

Original-patch-by Lennart Poettering <[email protected]>

Cc Steve Dickson <[email protected]>

Cc [email protected]

Acked-by Cristian Rodríguez<[email protected]>

Signed-off-by Tom Gundersen <[email protected]>

Signed-off-by Steve Dickson <[email protected]>

---
 Makefile.am   |  6 +++++
 configure.ac  | 10 ++++++++
 src/rpcbind.c | 81 ++++++++++++++++++++++++++++++++++++++++++++++++++++++-----
 3 files changed, 91 insertions(+), 6 deletions(-)

Makefile.am +6 -0

index 8715082..c99566d 100644
@@ -41,6 +41,12 @@ rpcbind_SOURCES = \
 	src/warmstart.c
 rpcbind_LDADD = $(TIRPC_LIBS)
 
+if SYSTEMD
+AM_CPPFLAGS += $(SYSTEMD_CFLAGS) -DSYSTEMD
+
+rpcbind_LDADD += $(SYSTEMD_LIBS)
+endif
+
 rpcinfo_SOURCES =       src/rpcinfo.c
 rpcinfo_LDADD   =       $(TIRPC_LIBS)
 

configure.ac +0 -0

index 5a88cc7..fdad639 100644

configure.ac +3 -0

+  fi
+AM_CONDITIONAL(SYSTEMD, [test -n "$with_systemdsystemunitdir" -a "x$with_systemdsystemunitdir" != xno ])
+
 AS_IF([test x$enable_libwrap = xyes], [
 	AC_CHECK_LIB([wrap], [hosts_access], ,
 		AC_MSG_ERROR([libwrap support requested but unable to find libwrap]))

src/rpcbind.c +30 -0

index e3462e3..f7c71ee 100644
@@ -56,6 +56,9 @@
 #include <netinet/in.h>
 #endif
 #include <arpa/inet.h>
+#ifdef SYSTEMD
+#include <systemd/sd-daemon.h>
+#endif
 #include <fcntl.h>
 #include <netdb.h>
 #include <stdio.h>

@@ -296,6 +299,7 @@ init_transport(struct netconfig *nconf)
 	u_int32_t host_addr[4];  /* IPv4 or IPv6 */
 	struct sockaddr_un sun;
 	mode_t oldmask;
+	int n;
         res = NULL;
 
 	if ((nconf->nc_semantics != NC_TPI_CLTS) &&

@@ -314,6 +318,76 @@ init_transport(struct netconfig *nconf)
 			fprintf(stderr, "[%d] - %s\n", i, *s);
 	}
 #endif
+	if (!__rpc_nconf2sockinfo(nconf, &si)) {
+		syslog(LOG_ERR, "cannot get information for %s",
+		    nconf->nc_netid);
+		return (1);
+	}
+
+#ifdef SYSTEMD
+	n = sd_listen_fds(0);
+	if (n < 0) {
+		syslog(LOG_ERR, "failed to acquire systemd sockets: %s", strerror(-n));
+		return 1;
+	}
+
+	/* Try to find if one of the systemd sockets we were given match
+	 * our netconfig structure. */
+
+	for (fd = SD_LISTEN_FDS_START; fd < SD_LISTEN_FDS_START + n; fd++) {
+		struct __rpc_sockinfo si_other;
+		union {
+			struct sockaddr sa;
+			struct sockaddr_un un;
+			struct sockaddr_in in4;
+			struct sockaddr_in6 in6;
+			struct sockaddr_storage storage;
+		} sa;
+		socklen_t addrlen = sizeof(sa);

src/rpcbind.c +34 -6

+
+		if (getsockname(fd, &sa.sa, &addrlen) < 0) {
+			syslog(LOG_ERR, "failed to query socket name: %s",
+                               strerror(errno));
+			goto error;
+		}
+
+		/* Copy the address */
+		taddr.addr.maxlen = taddr.addr.len = addrlen;
+		taddr.addr.buf = malloc(addrlen);
+		if (taddr.addr.buf == NULL) {
+			syslog(LOG_ERR,
+                               "cannot allocate memory for %s address",
+                               nconf->nc_netid);
+			goto error;
+		}
+		memcpy(taddr.addr.buf, &sa, addrlen);
+
+		my_xprt = (SVCXPRT *)svc_tli_create(fd, nconf, &taddr,
+                          RPC_MAXDATASIZE, RPC_MAXDATASIZE);
+		if (my_xprt == (SVCXPRT *)NULL) {
+			syslog(LOG_ERR, "%s: could not create service",
+                               nconf->nc_netid);
+			goto error;
+		}
+	}
+
+	/*
+	 * If none of the systemd sockets matched, we set up the socket in
+	 * the normal way:
+	 */
+#endif
+	if (my_xprt != NULL)
+		goto got_socket;
 
 	/*
 	 * XXX - using RPC library internal functions. For NC_TPI_CLTS

@@ -327,12 +401,6 @@ init_transport(struct netconfig *nconf)
 		}
 	}
 
-	if (!__rpc_nconf2sockinfo(nconf, &si)) {
-		syslog(LOG_ERR, "cannot get information for %s",
-		    nconf->nc_netid);
-		return (1);
-	}
-
 	if ((strcmp(nconf->nc_netid, "local") == 0) ||
 	    (strcmp(nconf->nc_netid, "unix") == 0)) {
 		memset(&sun, 0, sizeof sun);

Quoted 23 lines · Steve Dickson

From: Tom Gundersen <[email protected]>

Making rpcbind sockect activated will greatly simplify its integration in systemd systems. In essence, other services may now assume that rpcbind is always available, even during very early boot. This means that we no longer need to worry about any ordering dependencies.

This is based on a patch originally posted by Lennart Poettering:
<http://permalink.gmane.org/gmane.linux.nfs/33774>.

That patch was not merged due to the lack of a shared library and as systemd was seen to be too Fedora specific.

Systemd now provides a shared library, and it is (or very soon will be) the default init system on all the major Linux distributions.

This version of the patch has three changes from the original:

* It uses the shared library.
* It comes with unit files.
* It is rebased on top of master.

Quoted 2 lines

Please review the patch with "git show -b" or otherwise ignoring the whitespace changes, or it will be extremely difficult to read.

Thanks for working on this... Looks fine to me. Two suggestions below.

Quoted 50 lines

v4: reorganized the changes to make the diff easier to read
remove systemd scripts.

v3: rebase
fix typos
listen on /run/rpcbind.sock, rather than /var/run/rpcbind.sock (the latter is a symlink to the former, but this means the socket can be created before /var is mounted)
NB: this version has been compile-tested only as I no longer use rpcbind myself
v2: correctly enable systemd code at compile time
handle the case where not all the required sockets were supplied listen on udp/tcp port 111 in addition to /var/run/rpcbind.sock do not daemonize

Original-patch-by Lennart Poettering <[email protected]>

Cc Steve Dickson <[email protected]>

Cc [email protected]

Acked-by Cristian Rodríguez<[email protected]>

Signed-off-by Tom Gundersen <[email protected]>

Signed-off-by Steve Dickson <[email protected]>

---
 Makefile.am   |  6 +++++
 configure.ac  | 10 ++++++++
 src/rpcbind.c | 81 ++++++++++++++++++++++++++++++++++++++++++++++++++++++-----
 3 files changed, 91 insertions(+), 6 deletions(-)

Makefile.am +6 -0

index 8715082..c99566d 100644
@@ -41,6 +41,12 @@ rpcbind_SOURCES = \
 	src/warmstart.c
 rpcbind_LDADD = $(TIRPC_LIBS)
 
+if SYSTEMD
+AM_CPPFLAGS += $(SYSTEMD_CFLAGS) -DSYSTEMD
+
+rpcbind_LDADD += $(SYSTEMD_LIBS)
+endif
+
 rpcinfo_SOURCES =       src/rpcinfo.c
 rpcinfo_LDADD   =       $(TIRPC_LIBS)
 

configure.ac +0 -0

index 5a88cc7..fdad639 100644

configure.ac AC_SUBST([nss_modules], [$with_nss_modules]) · line 45

Quoted 10 lines

configure.ac +7 -0

@@ -36,6 +36,16 @@ AC_SUBST([nss_modules], [$with_nss_modules])
 
 PKG_CHECK_MODULES([TIRPC], [libtirpc])
 
+PKG_PROG_PKG_CONFIG
+AC_ARG_WITH([systemdsystemunitdir],
+  AS_HELP_STRING([--with-systemdsystemunitdir=DIR], [Directory for systemd service files]),
+  [], [with_systemdsystemunitdir=$($PKG_CONFIG --variable=systemdsystemunitdir systemd)])
+  if test "x$with_systemdsystemunitdir" != xno; then
+    AC_SUBST([systemdsystemunitdir], [$with_systemdsystemunitdir])
+    PKG_CHECK_MODULES([SYSTEMD], [libsystemd-daemon])

libsystemd-daemon got subsummed by libsystemd. So you should use something like

   PKG_CHECK_MODULES([SYSTEMD], [libsystemd], [],
      [PKG_CHECK_MODULES([SYSTEMD], [libsystemd-daemon], [],
       AC_MSG_ERROR([libsystemd support requested but found]))])

to get the new libary in preference to the old one.

Quoted 63 lines

configure.ac +3 -0

+  fi
+AM_CONDITIONAL(SYSTEMD, [test -n "$with_systemdsystemunitdir" -a "x$with_systemdsystemunitdir" != xno ])
+
 AS_IF([test x$enable_libwrap = xyes], [
 	AC_CHECK_LIB([wrap], [hosts_access], ,
 		AC_MSG_ERROR([libwrap support requested but unable to find libwrap]))

src/rpcbind.c +34 -0

index e3462e3..f7c71ee 100644
@@ -56,6 +56,9 @@
 #include <netinet/in.h>
 #endif
 #include <arpa/inet.h>
+#ifdef SYSTEMD
+#include <systemd/sd-daemon.h>
+#endif
 #include <fcntl.h>
 #include <netdb.h>
 #include <stdio.h>

@@ -296,6 +299,7 @@ init_transport(struct netconfig *nconf)
 	u_int32_t host_addr[4];  /* IPv4 or IPv6 */
 	struct sockaddr_un sun;
 	mode_t oldmask;
+	int n;
         res = NULL;
 
 	if ((nconf->nc_semantics != NC_TPI_CLTS) &&

@@ -314,6 +318,76 @@ init_transport(struct netconfig *nconf)
 			fprintf(stderr, "[%d] - %s\n", i, *s);
 	}
 #endif
+	if (!__rpc_nconf2sockinfo(nconf, &si)) {
+		syslog(LOG_ERR, "cannot get information for %s",
+		    nconf->nc_netid);
+		return (1);
+	}
+
+#ifdef SYSTEMD
+	n = sd_listen_fds(0);
+	if (n < 0) {
+		syslog(LOG_ERR, "failed to acquire systemd sockets: %s", strerror(-n));
+		return 1;
+	}
+
+	/* Try to find if one of the systemd sockets we were given match
+	 * our netconfig structure. */
+
+	for (fd = SD_LISTEN_FDS_START; fd < SD_LISTEN_FDS_START + n; fd++) {
+		struct __rpc_sockinfo si_other;
+		union {
+			struct sockaddr sa;
+			struct sockaddr_un un;
+			struct sockaddr_in in4;
+			struct sockaddr_in6 in6;
+			struct sockaddr_storage storage;
+		} sa;
+		socklen_t addrlen = sizeof(sa);
+
+		if (!__rpc_fd2sockinfo(fd, &si_other)) {
+			syslog(LOG_ERR, "cannot get information for fd %i", fd);
+			return 1;

src/rpcbind.c init_transport(struct netconfig *nconf) · line 356

Quoted 6 lines

src/rpcbind.c +6 -0

+		}
+
+		if (si.si_af != si_other.si_af ||
+                    si.si_socktype != si_other.si_socktype ||
+                    si.si_proto != si_other.si_proto)
+			continue;

If I understand correctly, this ignores the socket if it is different than expected. Shouldn't this result in an error instead?

Quoted 52 lines

src/rpcbind.c +34 -6

+
+		if (getsockname(fd, &sa.sa, &addrlen) < 0) {
+			syslog(LOG_ERR, "failed to query socket name: %s",
+                               strerror(errno));
+			goto error;
+		}
+
+		/* Copy the address */
+		taddr.addr.maxlen = taddr.addr.len = addrlen;
+		taddr.addr.buf = malloc(addrlen);
+		if (taddr.addr.buf == NULL) {
+			syslog(LOG_ERR,
+                               "cannot allocate memory for %s address",
+                               nconf->nc_netid);
+			goto error;
+		}
+		memcpy(taddr.addr.buf, &sa, addrlen);
+
+		my_xprt = (SVCXPRT *)svc_tli_create(fd, nconf, &taddr,
+                          RPC_MAXDATASIZE, RPC_MAXDATASIZE);
+		if (my_xprt == (SVCXPRT *)NULL) {
+			syslog(LOG_ERR, "%s: could not create service",
+                               nconf->nc_netid);
+			goto error;
+		}
+	}
+
+	/*
+	 * If none of the systemd sockets matched, we set up the socket in
+	 * the normal way:
+	 */
+#endif
+	if (my_xprt != NULL)
+		goto got_socket;
 
 	/*
 	 * XXX - using RPC library internal functions. For NC_TPI_CLTS

@@ -327,12 +401,6 @@ init_transport(struct netconfig *nconf)
 		}
 	}
 
-	if (!__rpc_nconf2sockinfo(nconf, &si)) {
-		syslog(LOG_ERR, "cannot get information for %s",
-		    nconf->nc_netid);
-		return (1);
-	}
-
 	if ((strcmp(nconf->nc_netid, "local") == 0) ||
 	    (strcmp(nconf->nc_netid, "unix") == 0)) {
 		memset(&sun, 0, sizeof sun);

src/rpcbind.c init_transport(struct netconfig *nconf) · line 643

Quoted 7 lines

src/rpcbind.c +1 -0

@@ -569,6 +637,7 @@ init_transport(struct netconfig *nconf)
 			goto error;
 		}
 	}
+got_socket:
 
 #ifdef PORTMAP
 	/*

Zbyszek