From 9097fe299f22c46316979356d945ebb494e85814 Mon Sep 17 00:00:00 2001
From: Lennart Poettering <lennart@poettering.net>
Date: Sun, 21 Apr 2013 22:24:50 -0300
Subject: [PATCH] bus: implement client logic for fd passing

---
 src/libsystemd-bus/bus-kernel.c      | 25 +++++++++++++++++++++++--
 src/libsystemd-bus/test-bus-kernel.c | 28 ++++++++++++++++++++++++++--
 2 files changed, 49 insertions(+), 4 deletions(-)

diff --git a/src/libsystemd-bus/bus-kernel.c b/src/libsystemd-bus/bus-kernel.c
index 5172b3211..115297dca 100644
--- a/src/libsystemd-bus/bus-kernel.c
+++ b/src/libsystemd-bus/bus-kernel.c
@@ -35,6 +35,7 @@
 
 #define KDBUS_ITEM_NEXT(item) \
         (typeof(item))(((uint8_t *)item) + ALIGN8((item)->size))
+
 #define KDBUS_ITEM_FOREACH(item, head)                                          \
         for (item = (head)->items;                                              \
              (uint8_t *)(item) < (uint8_t *)(head) + (head)->size;              \
@@ -100,6 +101,19 @@ static void* append_bloom(struct kdbus_msg_item **d, size_t length) {
         return r;
 }
 
+static void append_fds(struct kdbus_msg_item **d, const int fds[], unsigned n_fds) {
+        assert(d);
+        assert(fds);
+        assert(n_fds > 0);
+
+        *d = ALIGN8_PTR(*d);
+        (*d)->size = offsetof(struct kdbus_msg_item, fds) + sizeof(int) * n_fds;
+        (*d)->type = KDBUS_MSG_UNIX_FDS;
+        memcpy((*d)->fds, fds, sizeof(int) * n_fds);
+
+        *d = (struct kdbus_msg_item *) ((uint8_t*) *d + (*d)->size);
+}
+
 static int bus_message_setup_bloom(sd_bus_message *m, void *bloom) {
         unsigned i;
         int r;
@@ -200,6 +214,10 @@ static int bus_message_setup_kmsg(sd_bus *b, sd_bus_message *m) {
                 sz += ALIGN8(offsetof(struct kdbus_msg_item, str) + dl + 1);
         }
 
+        /* Add space for unix fds */
+        if (m->n_fds > 0)
+                sz += ALIGN8(offsetof(struct kdbus_msg_item, fds) + sizeof(int)*m->n_fds);
+
         m->kdbus = memalign(8, sz);
         if (!m->kdbus)
                 return -ENOMEM;
@@ -233,7 +251,6 @@ static int bus_message_setup_kmsg(sd_bus *b, sd_bus_message *m) {
         if (m->kdbus->dst_id == KDBUS_DST_ID_BROADCAST) {
                 void *p;
 
-                /* For now, let's add a mask all bloom filter */
                 p = append_bloom(&d, BLOOM_SIZE);
                 r = bus_message_setup_bloom(m, p);
                 if (r < 0) {
@@ -243,6 +260,9 @@ static int bus_message_setup_kmsg(sd_bus *b, sd_bus_message *m) {
                 }
         }
 
+        if (m->n_fds > 0)
+                append_fds(&d, m->fds, m->n_fds);
+
         m->kdbus->size = (uint8_t*) d - (uint8_t*) m->kdbus;
         assert(m->kdbus->size <= sz);
 
@@ -289,6 +309,7 @@ int bus_kernel_take_fd(sd_bus *b) {
 
         b->is_kernel = true;
         b->bus_client = true;
+        b->can_fds = true;
 
         r = bus_start_running(b);
         if (r < 0)
@@ -389,7 +410,7 @@ static int bus_kernel_make_message(sd_bus *bus, struct kdbus_msg *k, sd_bus_mess
                                 return -ENOMEM;
 
                         fds = f;
-                        memcpy(fds + n_fds, d->fds, j);
+                        memcpy(fds + n_fds, d->fds, sizeof(int) * j);
                         n_fds += j;
 
                 } else if (d->type == KDBUS_MSG_DST_NAME)
diff --git a/src/libsystemd-bus/test-bus-kernel.c b/src/libsystemd-bus/test-bus-kernel.c
index ffabdcbd1..1095e57e4 100644
--- a/src/libsystemd-bus/test-bus-kernel.c
+++ b/src/libsystemd-bus/test-bus-kernel.c
@@ -19,6 +19,8 @@
   along with systemd; If not, see <http://www.gnu.org/licenses/>.
 ***/
 
+#include <fcntl.h>
+
 #include "util.h"
 
 #include "sd-bus.h"
@@ -32,7 +34,7 @@ int main(int argc, char *argv[]) {
         _cleanup_bus_message_unref_ sd_bus_message *m = NULL;
         const char *ua = NULL, *ub = NULL, *the_string = NULL;
         sd_bus *a, *b;
-        int r;
+        int r, pipe_fds[2];
 
         bus_ref = bus_kernel_create("deine-mutter", &bus_name);
         if (bus_ref == -ENOENT)
@@ -108,6 +110,19 @@ int main(int argc, char *argv[]) {
         r = sd_bus_message_new_method_call(b, "net.x0pointer.foobar", "/a/path", "an.inter.face", "AMethod", &m);
         assert_se(r >= 0);
 
+        assert_se(pipe2(pipe_fds, O_CLOEXEC) >= 0);
+
+        assert_se(write(pipe_fds[1], "x", 1) == 1);
+
+        close_nointr_nofail(pipe_fds[1]);
+        pipe_fds[1] = -1;
+
+        r = sd_bus_message_append(m, "h", pipe_fds[0]);
+        assert_se(r >= 0);
+
+        close_nointr_nofail(pipe_fds[0]);
+        pipe_fds[0] = -1;
+
         r = sd_bus_send(b, m, NULL);
         assert_se(r >= 0);
 
@@ -121,8 +136,17 @@ int main(int argc, char *argv[]) {
                 bus_message_dump(m);
                 assert_se(sd_bus_message_rewind(m, true) >= 0);
 
-                if (sd_bus_message_is_method_call(m, "an.inter.face", "AMethod"))
+                if (sd_bus_message_is_method_call(m, "an.inter.face", "AMethod")) {
+                        int fd;
+                        char x;
+
+                        r = sd_bus_message_read(m, "h", &fd);
+                        assert_se(r >= 0);
+
+                        assert_se(read(fd, &x, 1) == 1);
+                        assert_se(x == 'x');
                         break;
+                }
         }
 
         r = sd_bus_release_name(a, "net.x0pointer.foobar");
-- 
2.30.2