chiark / gitweb /
bus: implement receiving side of memfd hookup
[elogind.git] / src / libsystemd-bus / bus-kernel.c
index 81469365f0ffdbd3ecae743e80a26feee3425d15..f7759b6fb498ea9f8c9926504124b86137139b80 100644 (file)
@@ -65,19 +65,32 @@ static int parse_unique_name(const char *s, uint64_t *id) {
 
 static void append_payload_vec(struct kdbus_item **d, const void *p, size_t sz) {
         assert(d);
-        assert(p);
         assert(sz > 0);
 
         *d = ALIGN8_PTR(*d);
 
         (*d)->size = offsetof(struct kdbus_item, vec) + sizeof(struct kdbus_vec);
         (*d)->type = KDBUS_MSG_PAYLOAD_VEC;
-        (*d)->vec.address = (uint64_t) p;
+        (*d)->vec.address = PTR_TO_UINT64(p);
         (*d)->vec.size = sz;
 
         *d = (struct kdbus_item *) ((uint8_t*) *d + (*d)->size);
 }
 
+static void append_payload_memfd(struct kdbus_item **d, int memfd, size_t sz) {
+        assert(d);
+        assert(memfd >= 0);
+        assert(sz > 0);
+
+        *d = ALIGN8_PTR(*d);
+        (*d)->size = offsetof(struct kdbus_item, memfd) + sizeof(struct kdbus_memfd);
+        (*d)->type = KDBUS_MSG_PAYLOAD_MEMFD;
+        (*d)->memfd.fd = memfd;
+        (*d)->memfd.size = sz;
+
+        *d = (struct kdbus_item *) ((uint8_t*) *d + (*d)->size);
+}
+
 static void append_destination(struct kdbus_item **d, const char *s, size_t length) {
         assert(d);
         assert(s);
@@ -210,6 +223,9 @@ static int bus_message_setup_kmsg(sd_bus *b, sd_bus_message *m) {
 
         sz = offsetof(struct kdbus_msg, items);
 
+        assert_cc(ALIGN8(offsetof(struct kdbus_item, vec) + sizeof(struct kdbus_vec)) ==
+                  ALIGN8(offsetof(struct kdbus_item, memfd) + sizeof(struct kdbus_memfd)));
+
         /* Add in fixed header, fields header and payload */
         sz += (1 + m->n_body_parts) *
                 ALIGN8(offsetof(struct kdbus_item, vec) + sizeof(struct kdbus_vec));
@@ -250,19 +266,38 @@ static int bus_message_setup_kmsg(sd_bus *b, sd_bus_message *m) {
                 append_destination(&d, m->destination, dl);
 
         append_payload_vec(&d, m->header, BUS_MESSAGE_BODY_BEGIN(m));
-        MESSAGE_FOREACH_PART(part, i, m)
+
+        MESSAGE_FOREACH_PART(part, i, m) {
+                if (part->is_zero) {
+                        append_payload_vec(&d, NULL, part->size);
+                        continue;
+                }
+
+                if (part->memfd >= 0 && part->sealed) {
+                        bus_body_part_unmap(part);
+
+                        if (!part->data) {
+                                append_payload_memfd(&d, part->memfd, part->size);
+                                continue;
+                        }
+                }
+
+                if (part->memfd >= 0) {
+                        r = bus_body_part_map(part);
+                        if (r < 0)
+                                goto fail;
+                }
+
                 append_payload_vec(&d, part->data, part->size);
+        }
 
         if (m->kdbus->dst_id == KDBUS_DST_ID_BROADCAST) {
                 void *p;
 
                 p = append_bloom(&d, BLOOM_SIZE);
                 r = bus_message_setup_bloom(m, p);
-                if (r < 0) {
-                        free(m->kdbus);
-                        m->kdbus = NULL;
-                        return -r;
-                }
+                if (r < 0)
+                        goto fail;
         }
 
         if (m->n_fds > 0)
@@ -274,6 +309,11 @@ static int bus_message_setup_kmsg(sd_bus *b, sd_bus_message *m) {
         m->free_kdbus = true;
 
         return 0;
+
+fail:
+        free(m->kdbus);
+        m->kdbus = NULL;
+        return r;
 }
 
 int bus_kernel_take_fd(sd_bus *b) {
@@ -387,17 +427,17 @@ static void close_kdbus_msg(sd_bus *bus, struct kdbus_msg *k) {
 
         KDBUS_ITEM_FOREACH(d, k) {
 
-                if (d->type != KDBUS_MSG_FDS)
-                        continue;
-
-                close_many(d->fds, (d->size - offsetof(struct kdbus_item, fds)) / sizeof(int));
+                if (d->type == KDBUS_MSG_FDS)
+                        close_many(d->fds, (d->size - offsetof(struct kdbus_item, fds)) / sizeof(int));
+                else if (d->type == KDBUS_MSG_PAYLOAD_MEMFD)
+                        close_nointr_nofail(d->memfd.fd);
         }
 }
 
 static int bus_kernel_make_message(sd_bus *bus, struct kdbus_msg *k, sd_bus_message **ret) {
         sd_bus_message *m = NULL;
         struct kdbus_item *d;
-        unsigned n_payload = 0, n_fds = 0;
+        unsigned n_fds = 0;
         _cleanup_free_ int *fds = NULL;
         struct bus_header *h = NULL;
         size_t total, n_bytes = 0, idx = 0;
@@ -425,9 +465,15 @@ static int bus_kernel_make_message(sd_bus *bus, struct kdbus_msg *k, sd_bus_mess
                                         return -EBADMSG;
                         }
 
-                        n_payload++;
                         n_bytes += d->vec.size;
 
+                } else if (d->type == KDBUS_MSG_PAYLOAD_MEMFD) {
+
+                        if (!h)
+                                return -EBADMSG;
+
+                        n_bytes += d->memfd.size;
+
                 } else if (d->type == KDBUS_MSG_FDS) {
                         int *f;
                         unsigned j;
@@ -441,9 +487,7 @@ static int bus_kernel_make_message(sd_bus *bus, struct kdbus_msg *k, sd_bus_mess
                         memcpy(fds + n_fds, d->fds, sizeof(int) * j);
                         n_fds += j;
 
-                } else if (d->type == KDBUS_MSG_DST_NAME)
-                        destination = d->str;
-                else if (d->type == KDBUS_MSG_SRC_SECLABEL)
+                } else if (d->type == KDBUS_MSG_SRC_SECLABEL)
                         seclabel = d->str;
         }
 
@@ -478,22 +522,42 @@ static int bus_kernel_make_message(sd_bus *bus, struct kdbus_msg *k, sd_bus_mess
 
                                 part = message_append_part(m);
                                 if (!part) {
-                                        sd_bus_message_unref(m);
-                                        return -ENOMEM;
+                                        r = -ENOMEM;
+                                        goto fail;
                                 }
 
                                 if (idx >= begin_body) {
                                         part->data = UINT64_TO_PTR(d->vec.address);
                                         part->size = d->vec.size;
                                 } else {
-                                        part->data = (uint8_t*) UINT64_TO_PTR(d->vec.address) + (begin_body - idx);
+                                        part->data = d->vec.address != 0 ? (uint8_t*) UINT64_TO_PTR(d->vec.address) + (begin_body - idx) : NULL;
                                         part->size = d->vec.size - (begin_body - idx);
                                 }
 
+                                part->is_zero = d->vec.address == 0;
                                 part->sealed = true;
                         }
 
                         idx += d->vec.size;
+                } else if (d->type == KDBUS_MSG_PAYLOAD_MEMFD) {
+                        struct bus_body_part *part;
+
+                        if (idx < BUS_MESSAGE_BODY_BEGIN(m)) {
+                                r = -EBADMSG;
+                                goto fail;
+                        }
+
+                        part = message_append_part(m);
+                        if (!part) {
+                                r = -ENOMEM;
+                                goto fail;
+                        }
+
+                        part->memfd = d->memfd.fd;
+                        part->size = d->memfd.size;
+                        part->sealed = true;
+
+                        idx += d->memfd.size;
 
                 } else if (d->type == KDBUS_MSG_SRC_CREDS) {
                         m->pid_starttime = d->creds.starttime / NSEC_PER_USEC;
@@ -521,17 +585,16 @@ static int bus_kernel_make_message(sd_bus *bus, struct kdbus_msg *k, sd_bus_mess
                 else if (d->type == KDBUS_MSG_SRC_CAPS) {
                         m->capability = d->data;
                         m->capability_size = l;
-                } else if (d->type != KDBUS_MSG_FDS &&
-                           d->type != KDBUS_MSG_DST_NAME &&
+                } else if (d->type == KDBUS_MSG_DST_NAME)
+                        destination = d->str;
+                else if (d->type != KDBUS_MSG_FDS &&
                            d->type != KDBUS_MSG_SRC_SECLABEL)
                         log_debug("Got unknown field from kernel %llu", d->type);
         }
 
         r = bus_message_parse_fields(m);
-        if (r < 0) {
-                sd_bus_message_unref(m);
-                return r;
-        }
+        if (r < 0)
+                goto fail;
 
         if (k->src_id == KDBUS_SRC_ID_KERNEL)
                 m->sender = "org.freedesktop.DBus";
@@ -560,6 +623,21 @@ static int bus_kernel_make_message(sd_bus *bus, struct kdbus_msg *k, sd_bus_mess
 
         *ret = m;
         return 1;
+
+fail:
+        if (m) {
+                struct bus_body_part *part;
+                unsigned i;
+
+                /* Make sure the memfds are not freed twice */
+                MESSAGE_FOREACH_PART(part, i, m)
+                        if (part->memfd >= 0)
+                                part->memfd = -1;
+
+                sd_bus_message_unref(m);
+        }
+
+        return r;
 }
 
 int bus_kernel_read_message(sd_bus *bus, sd_bus_message **m) {
@@ -577,15 +655,6 @@ int bus_kernel_read_message(sd_bus *bus, sd_bus_message **m) {
                 return -errno;
         }
 
-
-/*                 /\* Let's tell valgrind that there's really no need to */
-/*                  * initialize this fully. This should be removed again */
-/*                  * when valgrind learned the kdbus ioctls natively. *\/ */
-/* #ifdef HAVE_VALGRIND_MEMCHECK_H */
-/*                 VALGRIND_MAKE_MEM_DEFINED(k, sz); */
-/* #endif */
-
-
         r = bus_kernel_make_message(bus, k, m);
         if (r <= 0)
                 close_kdbus_msg(bus, k);