bus: add APIs for negotiating what is attached to messages

[elogind.git] / src / libsystemd-bus / bus-kernel.c

diff --git a/src/libsystemd-bus/bus-kernel.c b/src/libsystemd-bus/bus-kernel.c
index 8ef5752b311ce5cd237f88c19f3fedc5f881b998..107b2bd69401011df9244ad6183f8e59c75ba9c1 100644 (file)
--- a/src/libsystemd-bus/bus-kernel.c
+++ b/src/libsystemd-bus/bus-kernel.c
@@ -45,8 +45,6 @@
 #define KDBUS_ITEM_HEADER_SIZE offsetof(struct kdbus_item, data)
 #define KDBUS_ITEM_SIZE(s) ALIGN8((s) + KDBUS_ITEM_HEADER_SIZE)
 
-#define KDBUS_POOL_SIZE (4*1024*1024)
-
 static int parse_unique_name(const char *s, uint64_t *id) {
         int r;
 
@@ -347,15 +345,7 @@ int bus_kernel_take_fd(sd_bus *b) {
         }
 
         hello->size = sizeof(h);
-        hello->conn_flags =
-                KDBUS_HELLO_ACCEPT_FD|
-                KDBUS_HELLO_ATTACH_COMM|
-                KDBUS_HELLO_ATTACH_EXE|
-                KDBUS_HELLO_ATTACH_CMDLINE|
-                KDBUS_HELLO_ATTACH_CGROUP|
-                KDBUS_HELLO_ATTACH_CAPS|
-                KDBUS_HELLO_ATTACH_SECLABEL|
-                KDBUS_HELLO_ATTACH_AUDIT;
+        hello->conn_flags = b->hello_flags;
 
         hello->items[0].type = KDBUS_HELLO_POOL;
         hello->items[0].size = KDBUS_ITEM_HEADER_SIZE + sizeof(struct kdbus_vec);
@@ -380,7 +370,7 @@ int bus_kernel_take_fd(sd_bus *b) {
 
         b->is_kernel = true;
         b->bus_client = true;
-        b->can_fds = true;
+        b->can_fds = !!(hello->conn_flags & KDBUS_HELLO_ACCEPT_FD);
 
         r = bus_start_running(b);
         if (r < 0)
@@ -723,6 +713,7 @@ int bus_kernel_create(const char *name, char **s) {
 
 int bus_kernel_pop_memfd(sd_bus *bus, void **address, size_t *size) {
         struct memfd_cache *c;
+        int fd;
 
         assert(address);
         assert(size);
@@ -730,8 +721,12 @@ int bus_kernel_pop_memfd(sd_bus *bus, void **address, size_t *size) {
         if (!bus || !bus->is_kernel)
                 return -ENOTSUP;
 
+        assert_se(pthread_mutex_lock(&bus->memfd_cache_mutex) == 0);
+
         if (bus->n_memfd_cache <= 0) {
-                int fd, r;
+                int r;
+
+                assert_se(pthread_mutex_unlock(&bus->memfd_cache_mutex) == 0);
 
                 r = ioctl(bus->input_fd, KDBUS_CMD_MEMFD_NEW, &fd);
                 if (r < 0)
@@ -749,8 +744,18 @@ int bus_kernel_pop_memfd(sd_bus *bus, void **address, size_t *size) {
 
         *address = c->address;
         *size = c->size;
+        fd = c->fd;
+
+        assert_se(pthread_mutex_unlock(&bus->memfd_cache_mutex) == 0);
+
+        return fd;
+}
+
+static void close_and_munmap(int fd, void *address, size_t size) {
+        if (size > 0)
+                assert_se(munmap(address, PAGE_ALIGN(size)) == 0);
 
-        return c->fd;
+        close_nointr_nofail(fd);
 }
 
 void bus_kernel_push_memfd(sd_bus *bus, int fd, void *address, size_t size) {
@@ -759,13 +764,17 @@ void bus_kernel_push_memfd(sd_bus *bus, int fd, void *address, size_t size) {
         assert(fd >= 0);
         assert(size == 0 || address);
 
-        if (!bus || !bus->is_kernel ||
-            bus->n_memfd_cache >= ELEMENTSOF(bus->memfd_cache)) {
+        if (!bus || !bus->is_kernel) {
+                close_and_munmap(fd, address, size);
+                return;
+        }
 
-                if (size > 0)
-                        assert_se(munmap(address, PAGE_ALIGN(size)) == 0);
+        assert_se(pthread_mutex_lock(&bus->memfd_cache_mutex) == 0);
 
-                close_nointr_nofail(fd);
+        if (bus->n_memfd_cache >= ELEMENTSOF(bus->memfd_cache)) {
+                assert_se(pthread_mutex_unlock(&bus->memfd_cache_mutex) == 0);
+
+                close_and_munmap(fd, address, size);
                 return;
         }
 
@@ -782,6 +791,8 @@ void bus_kernel_push_memfd(sd_bus *bus, int fd, void *address, size_t size) {
                 c->size = MEMFD_CACHE_ITEM_SIZE_MAX;
         } else
                 c->size = size;
+
+        assert_se(pthread_mutex_unlock(&bus->memfd_cache_mutex) == 0);
 }
 
 void bus_kernel_flush_memfd(sd_bus *b) {