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authorLennart Poettering <lennart@poettering.net>2013-05-15 19:45:05 +0200
committerLennart Poettering <lennart@poettering.net>2013-05-15 19:45:45 +0200
commit453a0c2946da620f99825d39db335e9ea9861829 (patch)
treecb994a26bf2b84d0c6090e88d8ccb113aeef37e6 /src/libsystemd-bus
parent99271804172f6ac51be9556b2bdf37d6a7e952bc (diff)
bus: add support for adding memfds into message payload
Diffstat (limited to 'src/libsystemd-bus')
-rw-r--r--src/libsystemd-bus/bus-kernel.c3
-rw-r--r--src/libsystemd-bus/bus-message.c150
-rw-r--r--src/libsystemd-bus/bus-message.h7
-rw-r--r--src/libsystemd-bus/sd-memfd.c24
-rw-r--r--src/libsystemd-bus/test-bus-zero-copy.c112
5 files changed, 280 insertions, 16 deletions
diff --git a/src/libsystemd-bus/bus-kernel.c b/src/libsystemd-bus/bus-kernel.c
index 81469365f0..54a5e1691c 100644
--- a/src/libsystemd-bus/bus-kernel.c
+++ b/src/libsystemd-bus/bus-kernel.c
@@ -486,10 +486,11 @@ static int bus_kernel_make_message(sd_bus *bus, struct kdbus_msg *k, sd_bus_mess
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;
}
diff --git a/src/libsystemd-bus/bus-message.c b/src/libsystemd-bus/bus-message.c
index c1e1c468b8..747b44ac94 100644
--- a/src/libsystemd-bus/bus-message.c
+++ b/src/libsystemd-bus/bus-message.c
@@ -69,7 +69,9 @@ static void message_free_part(sd_bus_message *m, struct bus_body_part *part) {
close_nointr_nofail(part->memfd);
}
- } else if (part->free_this)
+ } else if (part->munmap_this)
+ munmap(part->data, part->mapped);
+ else if (part->free_this)
free(part->data);
if (part != &m->body)
@@ -1119,8 +1121,13 @@ static void part_zero(struct bus_body_part *part, size_t sz) {
assert(sz > 0);
assert(sz < 8);
- part->data = NULL;
+ /* All other fields can be left in their defaults */
+ assert(!part->data);
+ assert(part->memfd < 0);
+
part->size = sz;
+ part->is_zero = true;
+ part->sealed = true;
}
static int part_make_space(
@@ -1151,8 +1158,8 @@ static int part_make_space(
return -errno;
}
- if (sz > part->mapped) {
- size_t psz = PAGE_ALIGN(sz);
+ if (!part->data || sz > part->mapped) {
+ size_t psz = PAGE_ALIGN(sz > 0 ? sz : 1);
if (part->mapped <= 0)
n = mmap(NULL, psz, PROT_READ|PROT_WRITE, MAP_SHARED, part->memfd, 0);
@@ -1166,6 +1173,7 @@ static int part_make_space(
part->mapped = psz;
part->data = n;
+ part->munmap_this = true;
}
} else {
n = realloc(part->data, sz);
@@ -1185,8 +1193,22 @@ static int part_make_space(
return 0;
}
-static void *message_extend_body(sd_bus_message *m, size_t align, size_t sz) {
+static void message_extend_containers(sd_bus_message *m, size_t expand) {
struct bus_container *c;
+
+ assert(m);
+
+ if (expand <= 0)
+ return;
+
+ /* Update counters */
+ for (c = m->containers; c < m->containers + m->n_containers; c++)
+ if (c->array_size)
+ *c->array_size += expand;
+
+}
+
+static void *message_extend_body(sd_bus_message *m, size_t align, size_t sz) {
struct bus_body_part *part = NULL;
size_t start_body, end_body, padding, start_part, end_part, added;
bool add_new_part;
@@ -1234,6 +1256,7 @@ static void *message_extend_body(sd_bus_message *m, size_t align, size_t sz) {
if (r < 0)
return NULL;
} else {
+ struct bus_container *c;
void *op;
size_t os;
@@ -1260,12 +1283,8 @@ static void *message_extend_body(sd_bus_message *m, size_t align, size_t sz) {
m->error.message = (const char*) adjust_pointer(m->error.message, op, os, part->data);
}
- /* Update counters */
- for (c = m->containers; c < m->containers + m->n_containers; c++)
- if (c->array_size)
- *c->array_size += added;
-
m->header->body_size = end_body;
+ message_extend_containers(m, added);
return p;
}
@@ -2099,6 +2118,101 @@ int sd_bus_message_append_array(sd_bus_message *m, char type, const void *ptr, s
return 0;
}
+int sd_bus_message_append_array_memfd(sd_bus_message *m, char type, sd_memfd *memfd) {
+ _cleanup_close_ int copy_fd = -1;
+ struct bus_body_part *part;
+ ssize_t align, sz;
+ uint64_t size;
+ void *a;
+ int r;
+
+ if (!m)
+ return -EINVAL;
+ if (!memfd)
+ return -EINVAL;
+ if (m->sealed)
+ return -EPERM;
+ if (!bus_type_is_trivial(type))
+ return -EINVAL;
+ if (m->poisoned)
+ return -ESTALE;
+
+ r = sd_memfd_set_sealed(memfd, true);
+ if (r < 0)
+ return r;
+
+ copy_fd = sd_memfd_dup_fd(memfd);
+ if (copy_fd < 0)
+ return copy_fd;
+
+ r = sd_memfd_get_size(memfd, &size);
+ if (r < 0)
+ return r;
+
+ align = bus_type_get_alignment(type);
+ sz = bus_type_get_size(type);
+
+ assert_se(align > 0);
+ assert_se(sz > 0);
+
+ if (size % sz != 0)
+ return -EINVAL;
+
+ if (size > (size_t) (uint32_t) -1)
+ return -EINVAL;
+
+ r = sd_bus_message_open_container(m, SD_BUS_TYPE_ARRAY, CHAR_TO_STR(type));
+ if (r < 0)
+ return r;
+
+ a = message_extend_body(m, align, 0);
+ if (!a)
+ return -ENOMEM;
+
+ part = message_append_part(m);
+ if (!part)
+ return -ENOMEM;
+
+ part->memfd = copy_fd;
+ part->sealed = true;
+ part->size = size;
+ copy_fd = -1;
+
+ message_extend_containers(m, size);
+ m->header->body_size += size;
+
+ return sd_bus_message_close_container(m);
+}
+
+static int body_part_map_for_read(struct bus_body_part *part) {
+ void *p;
+ size_t psz;
+
+ assert_se(part);
+
+ if (part->data)
+ return 0;
+
+ if (part->size <= 0)
+ return 0;
+
+ psz = PAGE_ALIGN(part->size);
+
+ if (part->memfd >= 0)
+ p = mmap(NULL, psz, PROT_READ, MAP_SHARED, part->memfd, 0);
+ else if (part->is_zero)
+ p = mmap(NULL, psz, PROT_READ, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
+ else
+ return -EINVAL;
+
+ if (p == MAP_FAILED)
+ return -errno;
+
+ part->mapped = psz;
+ part->data = p;
+ return 0;
+}
+
static int buffer_peek(const void *p, uint32_t sz, size_t *rindex, size_t align, size_t nbytes, void **r) {
size_t k, start, end;
@@ -2139,6 +2253,8 @@ static bool message_end_of_array(sd_bus_message *m, size_t index) {
static struct bus_body_part* find_part(sd_bus_message *m, size_t index, size_t sz, void **p) {
struct bus_body_part *part;
size_t begin;
+ int r;
+
assert(m);
if (m->cached_rindex_part && index >= m->cached_rindex_part_begin) {
@@ -2154,8 +2270,13 @@ static struct bus_body_part* find_part(sd_bus_message *m, size_t index, size_t s
return NULL;
if (index + sz <= begin + part->size) {
+
+ r = body_part_map_for_read(part);
+ if (r < 0)
+ return NULL;
+
if (p)
- *p = part->data ? (uint8_t*) part->data + index - begin : NULL;
+ *p = (uint8_t*) part->data + index - begin;
m->cached_rindex_part = part;
m->cached_rindex_part_begin = begin;
@@ -2163,6 +2284,7 @@ static struct bus_body_part* find_part(sd_bus_message *m, size_t index, size_t s
return part;
}
+ begin += part->size;
part = part->next;
}
@@ -3638,7 +3760,8 @@ int bus_message_dump(sd_bus_message *m) {
"\treply_serial=%u\n"
"\terror.name=%s\n"
"\terror.message=%s\n"
- "\tsealed=%s\n",
+ "\tsealed=%s\n"
+ "\tn_body_parts=%u\n",
m,
m->n_ref,
m->header->endian,
@@ -3657,7 +3780,8 @@ int bus_message_dump(sd_bus_message *m) {
m->reply_serial,
strna(m->error.name),
strna(m->error.message),
- yes_no(m->sealed));
+ yes_no(m->sealed),
+ m->n_body_parts);
if (m->pid != 0)
printf("\tpid=%lu\n", (unsigned long) m->pid);
diff --git a/src/libsystemd-bus/bus-message.h b/src/libsystemd-bus/bus-message.h
index 2517514bac..f9c8fc9c08 100644
--- a/src/libsystemd-bus/bus-message.h
+++ b/src/libsystemd-bus/bus-message.h
@@ -33,9 +33,10 @@
struct bus_container {
char enclosing;
- char *signature;
unsigned index, saved_index;
+ char *signature;
+
uint32_t *array_size;
size_t before, begin;
};
@@ -51,13 +52,15 @@ struct bus_header {
} _packed_;
struct bus_body_part {
+ struct bus_body_part *next;
void *data;
size_t size;
size_t mapped;
int memfd;
bool free_this:1;
+ bool munmap_this:1;
bool sealed:1;
- struct bus_body_part *next;
+ bool is_zero:1;
};
struct sd_bus_message {
diff --git a/src/libsystemd-bus/sd-memfd.c b/src/libsystemd-bus/sd-memfd.c
index 2712a26f66..bd14da3a70 100644
--- a/src/libsystemd-bus/sd-memfd.c
+++ b/src/libsystemd-bus/sd-memfd.c
@@ -205,3 +205,27 @@ int sd_memfd_set_size(sd_memfd *m, uint64_t sz) {
return r;
}
+
+int sd_memfd_new_and_map(sd_memfd **m, size_t sz, void **p) {
+ sd_memfd *n;
+ int r;
+
+ r = sd_memfd_new(&n);
+ if (r < 0)
+ return r;
+
+ r = sd_memfd_set_size(n, sz);
+ if (r < 0) {
+ sd_memfd_free(n);
+ return r;
+ }
+
+ r = sd_memfd_map(n, 0, sz, p);
+ if (r < 0) {
+ sd_memfd_free(n);
+ return r;
+ }
+
+ *m = n;
+ return 0;
+}
diff --git a/src/libsystemd-bus/test-bus-zero-copy.c b/src/libsystemd-bus/test-bus-zero-copy.c
new file mode 100644
index 0000000000..024a0bfddf
--- /dev/null
+++ b/src/libsystemd-bus/test-bus-zero-copy.c
@@ -0,0 +1,112 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+/***
+ This file is part of systemd.
+
+ Copyright 2013 Lennart Poettering
+
+ systemd is free software; you can redistribute it and/or modify it
+ under the terms of the GNU Lesser General Public License as published by
+ the Free Software Foundation; either version 2.1 of the License, or
+ (at your option) any later version.
+
+ systemd is distributed in the hope that it will be useful, but
+ WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public License
+ along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include <fcntl.h>
+#include <sys/mman.h>
+
+#include "util.h"
+#include "log.h"
+
+#include "sd-bus.h"
+#include "sd-memfd.h"
+#include "bus-message.h"
+#include "bus-error.h"
+#include "bus-kernel.h"
+
+int main(int argc, char *argv[]) {
+ _cleanup_free_ char *bus_name = NULL, *address = NULL;
+ void *p;
+ sd_bus *a, *b;
+ int r, bus_ref;
+ sd_bus_message *m;
+ sd_memfd *f;
+
+ log_set_max_level(LOG_DEBUG);
+
+ bus_ref = bus_kernel_create("deine-mutter", &bus_name);
+ if (bus_ref == -ENOENT)
+ return EXIT_TEST_SKIP;
+
+ assert_se(bus_ref >= 0);
+
+ address = strappend("kernel:path=", bus_name);
+ assert_se(address);
+
+ r = sd_bus_new(&a);
+ assert_se(r >= 0);
+
+ r = sd_bus_new(&b);
+ assert_se(r >= 0);
+
+ r = sd_bus_set_address(a, address);
+ assert_se(r >= 0);
+
+ r = sd_bus_set_address(b, address);
+ assert_se(r >= 0);
+
+ r = sd_bus_start(a);
+ assert_se(r >= 0);
+
+ r = sd_bus_start(b);
+ assert_se(r >= 0);
+
+ r = sd_bus_message_new_method_call(b, ":1.1", "/a/path", "an.inter.face", "AMethod", &m);
+ assert_se(r >= 0);
+
+ r = sd_bus_message_open_container(m, 'r', "ayay");
+ assert_se(r >= 0);
+
+ r = sd_bus_message_append_array_space(m, 'y', 32, &p);
+ assert_se(r >= 0);
+
+ memset(p, 'L', 32);
+
+ r = sd_memfd_new_and_map(&f, 32, &p);
+ assert_se(r >= 0);
+
+ memset(p, 'P', 32);
+ munmap(p, 32);
+
+ r = sd_memfd_set_size(f, 32);
+ assert_se(r >= 0);
+
+ r = sd_bus_message_append_array_memfd(m, 'y', f);
+ assert_se(r >= 0);
+
+ r = sd_bus_message_close_container(m);
+ assert_se(r >= 0);
+
+ r = bus_message_seal(m, 55);
+ assert_se(r >= 0);
+
+ bus_message_dump(m);
+
+ r = sd_bus_send(b, m, NULL);
+ assert_se(r >= 0);
+
+ sd_bus_message_unref(m);
+
+ sd_bus_unref(a);
+ sd_bus_unref(b);
+ sd_memfd_free(f);
+
+ return 0;
+}