tree-wide: expose "p"-suffix unref calls in public APIs to make gcc cleanup easy

GLIB has recently started to officially support the gcc cleanup
attribute in its public API, hence let's do the same for our APIs.

With this patch we'll define an xyz_unrefp() call for each public
xyz_unref() call, to make it easy to use inside a
__attribute__((cleanup())) expression. Then, all code is ported over to
make use of this.

The new calls are also documented in the man pages, with examples how to
use them (well, I only added docs where the _unref() call itself already
had docs, and the examples, only cover sd_bus_unrefp() and
sd_event_unrefp()).

This also renames sd_lldp_free() to sd_lldp_unref(), since that's how we
tend to call our destructors these days.

Note that this defines no public macro that wraps gcc's attribute and
makes it easier to use. While I think it's our duty in the library to
make our stuff easy to use, I figure it's not our duty to make gcc's own
features easy to use on its own. Most likely, client code which wants to
make use of this should define its own:

       #define _cleanup_(function) __attribute__((cleanup(function)))

Or similar, to make the gcc feature easier to use.

Making this logic public has the benefit that we can remove three header
files whose only purpose was to define these functions internally.

See #2008.

8 files changed, 32 insertions, 39 deletions

diff --git a/src/libsystemd/sd-netlink/local-addresses.c b/src/libsystemd/sd-netlink/local-addresses.c
index d431ba4be4..997b048e58 100644
--- a/src/libsystemd/sd-netlink/local-addresses.c
+++ b/src/libsystemd/sd-netlink/local-addresses.c
@@ -56,8 +56,8 @@ static int address_compare(const void *_a, const void *_b) {
 }
 
 int local_addresses(sd_netlink *context, int ifindex, int af, struct local_address **ret) {
-        _cleanup_netlink_message_unref_ sd_netlink_message *req = NULL, *reply = NULL;
-        _cleanup_netlink_unref_ sd_netlink *rtnl = NULL;
+        _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *req = NULL, *reply = NULL;
+        _cleanup_(sd_netlink_unrefp) sd_netlink *rtnl = NULL;
         _cleanup_free_ struct local_address *list = NULL;
         size_t n_list = 0, n_allocated = 0;
         sd_netlink_message *m;
@@ -167,8 +167,8 @@ int local_addresses(sd_netlink *context, int ifindex, int af, struct local_addre
 }
 
 int local_gateways(sd_netlink *context, int ifindex, int af, struct local_address **ret) {
-        _cleanup_netlink_message_unref_ sd_netlink_message *req = NULL, *reply = NULL;
-        _cleanup_netlink_unref_ sd_netlink *rtnl = NULL;
+        _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *req = NULL, *reply = NULL;
+        _cleanup_(sd_netlink_unrefp) sd_netlink *rtnl = NULL;
         _cleanup_free_ struct local_address *list = NULL;
         sd_netlink_message *m = NULL;
         size_t n_list = 0, n_allocated = 0;
diff --git a/src/libsystemd/sd-netlink/netlink-internal.h b/src/libsystemd/sd-netlink/netlink-internal.h
index 8519a4d523..6c752ac65e 100644
--- a/src/libsystemd/sd-netlink/netlink-internal.h
+++ b/src/libsystemd/sd-netlink/netlink-internal.h
@@ -135,5 +135,5 @@ int rtnl_rqueue_make_room(sd_netlink *rtnl);
 int rtnl_rqueue_partial_make_room(sd_netlink *rtnl);
 
 /* Make sure callbacks don't destroy the rtnl connection */
-#define RTNL_DONT_DESTROY(rtnl) \
-        _cleanup_netlink_unref_ _unused_ sd_netlink *_dont_destroy_##rtnl = sd_netlink_ref(rtnl)
+#define NETLINK_DONT_DESTROY(rtnl) \
+        _cleanup_(sd_netlink_unrefp) _unused_ sd_netlink *_dont_destroy_##rtnl = sd_netlink_ref(rtnl)
diff --git a/src/libsystemd/sd-netlink/netlink-message.c b/src/libsystemd/sd-netlink/netlink-message.c
index 03971b3596..50792bc4a3 100644
--- a/src/libsystemd/sd-netlink/netlink-message.c
+++ b/src/libsystemd/sd-netlink/netlink-message.c
@@ -65,7 +65,7 @@ int message_new_empty(sd_netlink *rtnl, sd_netlink_message **ret) {
 }
 
 int message_new(sd_netlink *rtnl, sd_netlink_message **ret, uint16_t type) {
-        _cleanup_netlink_message_unref_ sd_netlink_message *m = NULL;
+        _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *m = NULL;
         const NLType *nl_type;
         size_t size;
         int r;
diff --git a/src/libsystemd/sd-netlink/netlink-socket.c b/src/libsystemd/sd-netlink/netlink-socket.c
index 13945202e4..2181201017 100644
--- a/src/libsystemd/sd-netlink/netlink-socket.c
+++ b/src/libsystemd/sd-netlink/netlink-socket.c
@@ -323,7 +323,7 @@ static int socket_recv_message(int fd, struct iovec *iov, uint32_t *_group, bool
  * On failure, a negative error code is returned.
  */
 int socket_read_message(sd_netlink *rtnl) {
-        _cleanup_netlink_message_unref_ sd_netlink_message *first = NULL;
+        _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *first = NULL;
         struct iovec iov = {};
         uint32_t group = 0;
         bool multi_part = false, done = false;
@@ -376,7 +376,7 @@ int socket_read_message(sd_netlink *rtnl) {
         }
 
         for (new_msg = rtnl->rbuffer; NLMSG_OK(new_msg, len) && !done; new_msg = NLMSG_NEXT(new_msg, len)) {
-                _cleanup_netlink_message_unref_ sd_netlink_message *m = NULL;
+                _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *m = NULL;
                 const NLType *nl_type;
 
                 if (!group && new_msg->nlmsg_pid != rtnl->sockaddr.nl.nl_pid)
diff --git a/src/libsystemd/sd-netlink/netlink-util.c b/src/libsystemd/sd-netlink/netlink-util.c
index 95690b7ff1..b69969e426 100644
--- a/src/libsystemd/sd-netlink/netlink-util.c
+++ b/src/libsystemd/sd-netlink/netlink-util.c
@@ -25,7 +25,7 @@
 #include "netlink-util.h"
 
 int rtnl_set_link_name(sd_netlink **rtnl, int ifindex, const char *name) {
-        _cleanup_netlink_message_unref_ sd_netlink_message *message = NULL;
+        _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *message = NULL;
         int r;
 
         assert(rtnl);
@@ -55,7 +55,7 @@ int rtnl_set_link_name(sd_netlink **rtnl, int ifindex, const char *name) {
 
 int rtnl_set_link_properties(sd_netlink **rtnl, int ifindex, const char *alias,
                              const struct ether_addr *mac, unsigned mtu) {
-        _cleanup_netlink_message_unref_ sd_netlink_message *message = NULL;
+        _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *message = NULL;
         int r;
 
         assert(rtnl);
diff --git a/src/libsystemd/sd-netlink/netlink-util.h b/src/libsystemd/sd-netlink/netlink-util.h
index acc6c15ff3..a0e59e1ec6 100644
--- a/src/libsystemd/sd-netlink/netlink-util.h
+++ b/src/libsystemd/sd-netlink/netlink-util.h
@@ -39,9 +39,3 @@ int rtnl_set_link_properties(sd_netlink **rtnl, int ifindex, const char *alias,
 
 int rtnl_log_parse_error(int r);
 int rtnl_log_create_error(int r);
-
-DEFINE_TRIVIAL_CLEANUP_FUNC(sd_netlink*, sd_netlink_unref);
-DEFINE_TRIVIAL_CLEANUP_FUNC(sd_netlink_message*, sd_netlink_message_unref);
-
-#define _cleanup_netlink_unref_ _cleanup_(sd_netlink_unrefp)
-#define _cleanup_netlink_message_unref_ _cleanup_(sd_netlink_message_unrefp)
diff --git a/src/libsystemd/sd-netlink/sd-netlink.c b/src/libsystemd/sd-netlink/sd-netlink.c
index 7c24e053cf..15d387df2c 100644
--- a/src/libsystemd/sd-netlink/sd-netlink.c
+++ b/src/libsystemd/sd-netlink/sd-netlink.c
@@ -35,7 +35,7 @@
 #include "util.h"
 
 static int sd_netlink_new(sd_netlink **ret) {
-        _cleanup_netlink_unref_ sd_netlink *rtnl = NULL;
+        _cleanup_(sd_netlink_unrefp) sd_netlink *rtnl = NULL;
 
         assert_return(ret, -EINVAL);
 
@@ -71,7 +71,7 @@ static int sd_netlink_new(sd_netlink **ret) {
 }
 
 int sd_netlink_new_from_netlink(sd_netlink **ret, int fd) {
-        _cleanup_netlink_unref_ sd_netlink *rtnl = NULL;
+        _cleanup_(sd_netlink_unrefp) sd_netlink *rtnl = NULL;
         socklen_t addrlen;
         int r;
 
@@ -105,7 +105,7 @@ static bool rtnl_pid_changed(sd_netlink *rtnl) {
 }
 
 int sd_netlink_open_fd(sd_netlink **ret, int fd) {
-        _cleanup_netlink_unref_ sd_netlink *rtnl = NULL;
+        _cleanup_(sd_netlink_unrefp) sd_netlink *rtnl = NULL;
         int r;
 
         assert_return(ret, -EINVAL);
@@ -286,7 +286,7 @@ static int dispatch_rqueue(sd_netlink *rtnl, sd_netlink_message **message) {
 }
 
 static int process_timeout(sd_netlink *rtnl) {
-        _cleanup_netlink_message_unref_ sd_netlink_message *m = NULL;
+        _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *m = NULL;
         struct reply_callback *c;
         usec_t n;
         int r;
@@ -376,7 +376,7 @@ static int process_match(sd_netlink *rtnl, sd_netlink_message *m) {
 }
 
 static int process_running(sd_netlink *rtnl, sd_netlink_message **ret) {
-        _cleanup_netlink_message_unref_ sd_netlink_message *m = NULL;
+        _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *m = NULL;
         int r;
 
         assert(rtnl);
@@ -418,7 +418,7 @@ null_message:
 }
 
 int sd_netlink_process(sd_netlink *rtnl, sd_netlink_message **ret) {
-        RTNL_DONT_DESTROY(rtnl);
+        NETLINK_DONT_DESTROY(rtnl);
         int r;
 
         assert_return(rtnl, -EINVAL);
@@ -623,7 +623,7 @@ int sd_netlink_call(sd_netlink *rtnl,
                         received_serial = rtnl_message_get_serial(rtnl->rqueue[i]);
 
                         if (received_serial == serial) {
-                                _cleanup_netlink_message_unref_ sd_netlink_message *incoming = NULL;
+                                _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *incoming = NULL;
                                 uint16_t type;
 
                                 incoming = rtnl->rqueue[i];
diff --git a/src/libsystemd/sd-netlink/test-netlink.c b/src/libsystemd/sd-netlink/test-netlink.c
index 58b774e0e1..6a8b4d31d1 100644
--- a/src/libsystemd/sd-netlink/test-netlink.c
+++ b/src/libsystemd/sd-netlink/test-netlink.c
@@ -25,7 +25,6 @@
 #include "sd-netlink.h"
 
 #include "ether-addr-util.h"
-#include "event-util.h"
 #include "macro.h"
 #include "missing.h"
 #include "netlink-util.h"
@@ -34,7 +33,7 @@
 #include "util.h"
 
 static void test_message_link_bridge(sd_netlink *rtnl) {
-        _cleanup_netlink_message_unref_ sd_netlink_message *message = NULL;
+        _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *message = NULL;
         uint32_t cost;
 
         assert_se(sd_rtnl_message_new_link(rtnl, &message, RTM_NEWLINK, 1) >= 0);
@@ -52,7 +51,7 @@ static void test_message_link_bridge(sd_netlink *rtnl) {
 }
 
 static void test_link_configure(sd_netlink *rtnl, int ifindex) {
-        _cleanup_netlink_message_unref_ sd_netlink_message *message = NULL;
+        _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *message = NULL;
         const char *mac = "98:fe:94:3f:c6:18", *name = "test";
         char buffer[ETHER_ADDR_TO_STRING_MAX];
         unsigned int mtu = 1450, mtu_out;
@@ -146,7 +145,7 @@ static void test_address_get(sd_netlink *rtnl, int ifindex) {
 }
 
 static void test_route(void) {
-        _cleanup_netlink_message_unref_ sd_netlink_message *req;
+        _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *req;
         struct in_addr addr, addr_data;
         uint32_t index = 2, u32_data;
         int r;
@@ -209,9 +208,9 @@ static int link_handler(sd_netlink *rtnl, sd_netlink_message *m, void *userdata)
 }
 
 static void test_event_loop(int ifindex) {
-        _cleanup_event_unref_ sd_event *event = NULL;
-        _cleanup_netlink_unref_ sd_netlink *rtnl = NULL;
-        _cleanup_netlink_message_unref_ sd_netlink_message *m = NULL;
+        _cleanup_(sd_event_unrefp) sd_event *event = NULL;
+        _cleanup_(sd_netlink_unrefp) sd_netlink *rtnl = NULL;
+        _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *m = NULL;
         char *ifname;
 
         ifname = strdup("lo2");
@@ -249,8 +248,8 @@ static int pipe_handler(sd_netlink *rtnl, sd_netlink_message *m, void *userdata)
 }
 
 static void test_async(int ifindex) {
-        _cleanup_netlink_unref_ sd_netlink *rtnl = NULL;
-        _cleanup_netlink_message_unref_ sd_netlink_message *m = NULL, *r = NULL;
+        _cleanup_(sd_netlink_unrefp) sd_netlink *rtnl = NULL;
+        _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *m = NULL, *r = NULL;
         uint32_t serial;
         char *ifname;
 
@@ -270,8 +269,8 @@ static void test_async(int ifindex) {
 }
 
 static void test_pipe(int ifindex) {
-        _cleanup_netlink_unref_ sd_netlink *rtnl = NULL;
-        _cleanup_netlink_message_unref_ sd_netlink_message *m1 = NULL, *m2 = NULL;
+        _cleanup_(sd_netlink_unrefp) sd_netlink *rtnl = NULL;
+        _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *m1 = NULL, *m2 = NULL;
         int counter = 0;
 
         assert_se(sd_netlink_open(&rtnl) >= 0);
@@ -294,7 +293,7 @@ static void test_pipe(int ifindex) {
 }
 
 static void test_container(void) {
-        _cleanup_netlink_message_unref_ sd_netlink_message *m = NULL;
+        _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *m = NULL;
         uint16_t u16_data;
         uint32_t u32_data;
         const char *string_data;
@@ -329,7 +328,7 @@ static void test_container(void) {
 }
 
 static void test_match(void) {
-        _cleanup_netlink_unref_ sd_netlink *rtnl = NULL;
+        _cleanup_(sd_netlink_unrefp) sd_netlink *rtnl = NULL;
 
         assert_se(sd_netlink_open(&rtnl) >= 0);
 
@@ -344,7 +343,7 @@ static void test_match(void) {
 }
 
 static void test_get_addresses(sd_netlink *rtnl) {
-        _cleanup_netlink_message_unref_ sd_netlink_message *req = NULL, *reply = NULL;
+        _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *req = NULL, *reply = NULL;
         sd_netlink_message *m;
 
         assert_se(sd_rtnl_message_new_addr(rtnl, &req, RTM_GETADDR, 0, AF_UNSPEC) >= 0);
@@ -372,7 +371,7 @@ static void test_get_addresses(sd_netlink *rtnl) {
 }
 
 static void test_message(void) {
-        _cleanup_netlink_message_unref_ sd_netlink_message *m = NULL;
+        _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *m = NULL;
 
         assert_se(rtnl_message_new_synthetic_error(-ETIMEDOUT, 1, &m) >= 0);
         assert_se(sd_netlink_message_get_errno(m) == -ETIMEDOUT);