From 1307c3ff9aa9d96fff6f9f42bb760887fa9aa240 Mon Sep 17 00:00:00 2001 From: Lennart Poettering Date: Thu, 16 May 2013 02:37:42 +0200 Subject: [PATCH] bus: implement receiving side of memfd hookup --- src/libsystemd-bus/bus-kernel.c | 80 +++++++++++++++++-------- src/libsystemd-bus/bus-message.c | 10 +++- src/libsystemd-bus/test-bus-zero-copy.c | 6 ++ 3 files changed, 67 insertions(+), 29 deletions(-) diff --git a/src/libsystemd-bus/bus-kernel.c b/src/libsystemd-bus/bus-kernel.c index a0e892a49..f7759b6fb 100644 --- a/src/libsystemd-bus/bus-kernel.c +++ b/src/libsystemd-bus/bus-kernel.c @@ -427,17 +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; @@ -465,9 +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; @@ -481,9 +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; } @@ -518,8 +522,8 @@ 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) { @@ -535,6 +539,25 @@ static int bus_kernel_make_message(sd_bus *bus, struct kdbus_msg *k, sd_bus_mess } 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; @@ -562,17 +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"; @@ -601,6 +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) { @@ -618,15 +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); diff --git a/src/libsystemd-bus/bus-message.c b/src/libsystemd-bus/bus-message.c index b5a311530..209fd71c1 100644 --- a/src/libsystemd-bus/bus-message.c +++ b/src/libsystemd-bus/bus-message.c @@ -2196,6 +2196,13 @@ int bus_body_part_map(struct bus_body_part *part) { if (part->size <= 0) return 0; + /* For smaller zero parts (as used for padding) we don't need to map anything... */ + if (part->memfd < 0 && part->is_zero && part->size < 8) { + static const uint8_t zeroes[7] = { }; + part->data = (void*) zeroes; + return 0; + } + psz = PAGE_ALIGN(part->size); if (part->memfd >= 0) @@ -2222,9 +2229,6 @@ void bus_body_part_unmap(struct bus_body_part *part) { if (part->memfd < 0) return; - if (!part->sealed) - return; - if (!part->data) return; diff --git a/src/libsystemd-bus/test-bus-zero-copy.c b/src/libsystemd-bus/test-bus-zero-copy.c index 0d8435ec1..5a9f45489 100644 --- a/src/libsystemd-bus/test-bus-zero-copy.c +++ b/src/libsystemd-bus/test-bus-zero-copy.c @@ -111,6 +111,12 @@ int main(int argc, char *argv[]) { sd_bus_message_unref(m); + r = sd_bus_process(a, &m); + assert_se(r > 0); + + bus_message_dump(m); + sd_bus_message_unref(m); + sd_bus_unref(a); sd_bus_unref(b); -- 2.30.2