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-rw-r--r--src/libsystemd/sd-bus/PORTING-DBUS140
-rw-r--r--src/libsystemd/sd-bus/bus-kernel.c21
-rw-r--r--src/libsystemd/sd-bus/bus-message.c10
-rw-r--r--src/libsystemd/sd-bus/kdbus.h51
-rw-r--r--src/libsystemd/sd-bus/sd-memfd.c54
-rw-r--r--src/libsystemd/sd-bus/test-bus-memfd.c180
6 files changed, 28 insertions, 328 deletions
diff --git a/src/libsystemd/sd-bus/PORTING-DBUS1 b/src/libsystemd/sd-bus/PORTING-DBUS1
index 6205e32736..9f0a91d695 100644
--- a/src/libsystemd/sd-bus/PORTING-DBUS1
+++ b/src/libsystemd/sd-bus/PORTING-DBUS1
@@ -362,46 +362,6 @@ ioctl()s are added for a single match strings.
MEMFDS
-The "memfd" concept is used for zero-copy data transfers (see
-above). memfds are file descriptors to memory chunks of arbitrary
-sizes. If you have a memfd you can mmap() it to get access to the data
-it contains or write to it. They are comparable to file descriptors to
-unlinked files on a tmpfs, or to anonymous memory that one may refer
-to with an fd. They have one particular property: they can be
-"sealed". A memfd that is "sealed" is protected from alteration. Only
-memfds that are currently not mapped and to which a single fd refers
-may be sealed (they may also be unsealed in that case).
-
-The concept of "sealing" makes memfds useful for using them as
-transport for kdbus messages: only when the receiver knows that the
-message it has received cannot change while looking at, it can safely
-parse it without having to copy it to a safe memory area. memfds can also
-be reused in multiple messages. A sender may send the same memfd to
-multiple peers, and since it is sealed, it can be sure that the receiver
-will not be able to modify it. "Sealing" hence provides both sides of
-a transaction with the guarantee that the data stays constant and is
-reusable.
-
-memfds are a generic concept that can be used outside of the immediate
-kdbus usecase. You can send them across AF_UNIX sockets too, sealed or
-unsealed. In kdbus themselves, they can be used to send zero-copy
-payloads, but may also be sent as normal fds.
-
-memfds are allocated with the KDBUS_CMD_MEMFD_NEW ioctl. After allocation,
-simply memory map them and write to them. To set their size, use
-KDBUS_CMD_MEMFD_SIZE_SET. Note that memfds will be increased in size
-automatically if you touch previously unallocated pages. However, the
-size will only be increased in multiples of the page size in that
-case. Thus, in almost all cases, an explicit KDBUS_CMD_MEMFD_SIZE_SET
-is necessary, since it allows setting memfd sizes in finer
-granularity. To seal a memfd use the KDBUS_CMD_MEMFD_SEAL_SET ioctl
-call. It will only succeed if the caller has the only fd reference to
-the memfd open, and if the memfd is currently unmapped.
-
-If memfds are shared, keep in mind that the file pointer used by
-write/read/seek is shared too, only pread/pwrite are safe to use
-in that case.
-
memfds may be sent across kdbus via KDBUS_ITEM_PAYLOAD_MEMFD items
attached to messages. If this is done, the data included in the memfd
is considered part of the payload stream of a message, and are treated
diff --git a/src/libsystemd/sd-bus/bus-kernel.c b/src/libsystemd/sd-bus/bus-kernel.c
index 8b961c38eb..4156b90265 100644
--- a/src/libsystemd/sd-bus/bus-kernel.c
+++ b/src/libsystemd/sd-bus/bus-kernel.c
@@ -1111,9 +1111,6 @@ int bus_kernel_pop_memfd(sd_bus *bus, void **address, size_t *mapped, size_t *al
if (bus->n_memfd_cache <= 0) {
_cleanup_free_ char *g = NULL;
- struct kdbus_cmd_memfd_make *cmd;
- struct kdbus_item *item;
- size_t l, sz;
int r;
assert_se(pthread_mutex_unlock(&bus->memfd_cache_mutex) >= 0);
@@ -1124,26 +1121,14 @@ int bus_kernel_pop_memfd(sd_bus *bus, void **address, size_t *mapped, size_t *al
if (!g)
return -ENOMEM;
- l = strlen(g);
- sz = ALIGN8(offsetof(struct kdbus_cmd_memfd_make, items)) +
- ALIGN8(offsetof(struct kdbus_item, str)) +
- l + 1;
- cmd = alloca0(sz);
- cmd->size = sz;
-
- item = cmd->items;
- item->size = ALIGN8(offsetof(struct kdbus_item, str)) + l + 1;
- item->type = KDBUS_ITEM_MEMFD_NAME;
- memcpy(item->str, g, l + 1);
-
- r = ioctl(bus->input_fd, KDBUS_CMD_MEMFD_NEW, cmd);
+ r = memfd_create(g, 0, MFD_ALLOW_SEALING);
if (r < 0)
return -errno;
*address = NULL;
*mapped = 0;
*allocated = 0;
- return cmd->fd;
+ return r;
}
c = &bus->memfd_cache[--bus->n_memfd_cache];
@@ -1195,7 +1180,7 @@ void bus_kernel_push_memfd(sd_bus *bus, int fd, void *address, size_t mapped, si
/* If overly long, let's return a bit to the OS */
if (mapped > max_mapped) {
- assert_se(ioctl(fd, KDBUS_CMD_MEMFD_SIZE_SET, &max_mapped) >= 0);
+ assert_se(ftruncate(fd, max_mapped) >= 0);
assert_se(munmap((uint8_t*) address + max_mapped, PAGE_ALIGN(mapped - max_mapped)) >= 0);
c->mapped = c->allocated = max_mapped;
} else {
diff --git a/src/libsystemd/sd-bus/bus-message.c b/src/libsystemd/sd-bus/bus-message.c
index 4768a1fa9e..79dc471d41 100644
--- a/src/libsystemd/sd-bus/bus-message.c
+++ b/src/libsystemd/sd-bus/bus-message.c
@@ -1076,7 +1076,7 @@ static int part_make_space(
uint64_t new_allocated;
new_allocated = PAGE_ALIGN(sz > 0 ? 2 * sz : 1);
- r = ioctl(part->memfd, KDBUS_CMD_MEMFD_SIZE_SET, &new_allocated);
+ r = ftruncate(part->memfd, new_allocated);
if (r < 0) {
m->poisoned = true;
return -errno;
@@ -2546,7 +2546,7 @@ _public_ int sd_bus_message_append_array_memfd(sd_bus_message *m,
if (m->poisoned)
return -ESTALE;
- r = sd_memfd_set_sealed(memfd, true);
+ r = sd_memfd_set_sealed(memfd);
if (r < 0)
return r;
@@ -2606,7 +2606,7 @@ _public_ int sd_bus_message_append_string_memfd(sd_bus_message *m, sd_memfd *mem
assert_return(!m->sealed, -EPERM);
assert_return(!m->poisoned, -ESTALE);
- r = sd_memfd_set_sealed(memfd, true);
+ r = sd_memfd_set_sealed(memfd);
if (r < 0)
return r;
@@ -2799,11 +2799,11 @@ int bus_message_seal(sd_bus_message *m, uint64_t cookie, usec_t timeout) {
/* Then, sync up real memfd size */
sz = part->size;
- if (ioctl(part->memfd, KDBUS_CMD_MEMFD_SIZE_SET, &sz) < 0)
+ if (ftruncate(part->memfd, sz) < 0)
return -errno;
/* Finally, try to seal */
- if (ioctl(part->memfd, KDBUS_CMD_MEMFD_SEAL_SET, 1) >= 0)
+ if (fcntl(part->memfd, F_ADD_SEALS, F_SEAL_SHRINK | F_SEAL_GROW | F_SEAL_WRITE) >= 0)
part->sealed = true;
}
}
diff --git a/src/libsystemd/sd-bus/kdbus.h b/src/libsystemd/sd-bus/kdbus.h
index b060330cb6..3751f9ca24 100644
--- a/src/libsystemd/sd-bus/kdbus.h
+++ b/src/libsystemd/sd-bus/kdbus.h
@@ -734,24 +734,6 @@ struct kdbus_cmd_match {
} __attribute__((aligned(8)));
/**
- * struct kdbus_cmd_memfd_make - create a kdbus memfd
- * @size: The total size of the struct
- * @file_size: The initial file size
- * @fd: The returned file descriptor number
- * @__pad: Padding to ensure proper alignement
- * @items: A list of items for additional information
- *
- * This structure is used with the KDBUS_CMD_MEMFD_NEW ioctl.
- */
-struct kdbus_cmd_memfd_make {
- __u64 size;
- __u64 file_size;
- int fd;
- __u32 __pad;
- struct kdbus_item items[0];
-} __attribute__((aligned(8)));
-
-/**
* enum kdbus_ioctl_type - Ioctl API
* @KDBUS_CMD_BUS_MAKE: After opening the "control" device node, this
* command creates a new bus with the specified
@@ -801,32 +783,6 @@ struct kdbus_cmd_memfd_make {
* @KDBUS_CMD_MATCH_ADD: Install a match which broadcast messages should
* be delivered to the connection.
* @KDBUS_CMD_MATCH_REMOVE: Remove a current match for broadcast messages.
- * @KDBUS_CMD_MEMFD_NEW: Return a new file descriptor which provides an
- * anonymous shared memory file and which can be
- * used to pass around larger chunks of data.
- * Kdbus memfd files can be sealed, which allows
- * the receiver to trust the data it has received.
- * Kdbus memfd files expose only very limited
- * operations, they can be mmap()ed, seek()ed,
- * (p)read(v)() and (p)write(v)(); most other
- * common file operations are not implemented.
- * Special caution needs to be taken with
- * read(v)()/write(v)() on a shared file; the
- * underlying file position is always shared
- * between all users of the file and race against
- * each other, pread(v)()/pwrite(v)() avoid these
- * issues.
- * @KDBUS_CMD_MEMFD_SIZE_GET: Return the size of the underlying file, which
- * changes with write().
- * @KDBUS_CMD_MEMFD_SIZE_SET: Truncate the underlying file to the specified
- * size.
- * @KDBUS_CMD_MEMFD_SEAL_GET: Return the state of the file sealing.
- * @KDBUS_CMD_MEMFD_SEAL_SET: Seal or break a seal of the file. Only files
- * which are not shared with other processes and
- * which are currently not mapped can be sealed.
- * The current process needs to be the one and
- * single owner of the file, the sealing cannot
- * be changed as long as the file is shared.
*/
enum kdbus_ioctl_type {
KDBUS_CMD_BUS_MAKE = _IOW(KDBUS_IOCTL_MAGIC, 0x00,
@@ -866,13 +822,6 @@ enum kdbus_ioctl_type {
struct kdbus_cmd_match),
KDBUS_CMD_MATCH_REMOVE = _IOW(KDBUS_IOCTL_MAGIC, 0x81,
struct kdbus_cmd_match),
-
- KDBUS_CMD_MEMFD_NEW = _IOWR(KDBUS_IOCTL_MAGIC, 0xc0,
- struct kdbus_cmd_memfd_make),
- KDBUS_CMD_MEMFD_SIZE_GET = _IOR(KDBUS_IOCTL_MAGIC, 0xc1, __u64 *),
- KDBUS_CMD_MEMFD_SIZE_SET = _IOW(KDBUS_IOCTL_MAGIC, 0xc2, __u64 *),
- KDBUS_CMD_MEMFD_SEAL_GET = _IOR(KDBUS_IOCTL_MAGIC, 0xc3, int *),
- KDBUS_CMD_MEMFD_SEAL_SET = _IO(KDBUS_IOCTL_MAGIC, 0xc4),
};
/*
diff --git a/src/libsystemd/sd-bus/sd-memfd.c b/src/libsystemd/sd-bus/sd-memfd.c
index fcf3e73124..16d09e3e14 100644
--- a/src/libsystemd/sd-bus/sd-memfd.c
+++ b/src/libsystemd/sd-bus/sd-memfd.c
@@ -26,8 +26,8 @@
#include <sys/prctl.h>
#include "util.h"
-#include "kdbus.h"
#include "bus-label.h"
+#include "missing.h"
#include "sd-memfd.h"
#include "sd-bus.h"
@@ -39,11 +39,8 @@ struct sd_memfd {
_public_ int sd_memfd_new(sd_memfd **m, const char *name) {
- struct kdbus_cmd_memfd_make *cmd;
- struct kdbus_item *item;
_cleanup_close_ int kdbus = -1;
_cleanup_free_ char *g = NULL;
- size_t sz, l;
sd_memfd *n;
assert_return(m, -EINVAL);
@@ -89,42 +86,28 @@ _public_ int sd_memfd_new(sd_memfd **m, const char *name) {
}
}
- l = strlen(name);
- sz = ALIGN8(offsetof(struct kdbus_cmd_memfd_make, items)) +
- ALIGN8(offsetof(struct kdbus_item, str)) +
- l + 1;
-
- cmd = alloca0(sz);
- cmd->size = sz;
-
- item = cmd->items;
- item->size = ALIGN8(offsetof(struct kdbus_item, str)) + l + 1;
- item->type = KDBUS_ITEM_MEMFD_NAME;
- memcpy(item->str, name, l + 1);
-
- if (ioctl(kdbus, KDBUS_CMD_MEMFD_NEW, cmd) < 0)
- return -errno;
-
n = new0(struct sd_memfd, 1);
- if (!n) {
- safe_close(cmd->fd);
+ if (!n)
return -ENOMEM;
+
+ n->fd = memfd_create(name, 0, MFD_ALLOW_SEALING);
+ if (n->fd < 0) {
+ free(n);
+ return -errno;
}
- n->fd = cmd->fd;
*m = n;
return 0;
}
_public_ int sd_memfd_new_from_fd(sd_memfd **m, int fd) {
sd_memfd *n;
- uint64_t sz;
assert_return(m, -EINVAL);
assert_return(fd >= 0, -EINVAL);
- /* Check if this is a valid memfd */
- if (ioctl(fd, KDBUS_CMD_MEMFD_SIZE_GET, &sz) < 0)
+ /* Check if this is a sealable fd */
+ if (fcntl(fd, F_GET_SEALS) < 0)
return -ENOTTY;
n = new0(struct sd_memfd, 1);
@@ -193,7 +176,7 @@ _public_ int sd_memfd_map(sd_memfd *m, uint64_t offset, size_t size, void **p) {
if (sealed < 0)
return sealed;
- q = mmap(NULL, size, sealed ? PROT_READ : PROT_READ|PROT_WRITE, MAP_SHARED, m->fd, offset);
+ q = mmap(NULL, size, sealed ? PROT_READ : PROT_READ|PROT_WRITE, MAP_PRIVATE, m->fd, offset);
if (q == MAP_FAILED)
return -errno;
@@ -201,12 +184,12 @@ _public_ int sd_memfd_map(sd_memfd *m, uint64_t offset, size_t size, void **p) {
return 0;
}
-_public_ int sd_memfd_set_sealed(sd_memfd *m, int b) {
+_public_ int sd_memfd_set_sealed(sd_memfd *m) {
int r;
assert_return(m, -EINVAL);
- r = ioctl(m->fd, KDBUS_CMD_MEMFD_SEAL_SET, b);
+ r = fcntl(m->fd, F_ADD_SEALS, F_SEAL_SHRINK | F_SEAL_GROW | F_SEAL_WRITE);
if (r < 0)
return -errno;
@@ -214,27 +197,30 @@ _public_ int sd_memfd_set_sealed(sd_memfd *m, int b) {
}
_public_ int sd_memfd_get_sealed(sd_memfd *m) {
- int r, b;
+ int r;
assert_return(m, -EINVAL);
- r = ioctl(m->fd, KDBUS_CMD_MEMFD_SEAL_GET, &b);
+ r = fcntl(m->fd, F_GET_SEALS);
if (r < 0)
return -errno;
- return !!b;
+ return (r & (F_SEAL_SHRINK | F_SEAL_GROW | F_SEAL_WRITE)) ==
+ (F_SEAL_SHRINK | F_SEAL_GROW | F_SEAL_WRITE);
}
_public_ int sd_memfd_get_size(sd_memfd *m, uint64_t *sz) {
int r;
+ struct stat stat;
assert_return(m, -EINVAL);
assert_return(sz, -EINVAL);
- r = ioctl(m->fd, KDBUS_CMD_MEMFD_SIZE_GET, sz);
+ r = fstat(m->fd, &stat);
if (r < 0)
return -errno;
+ *sz = stat.st_size;
return r;
}
@@ -243,7 +229,7 @@ _public_ int sd_memfd_set_size(sd_memfd *m, uint64_t sz) {
assert_return(m, -EINVAL);
- r = ioctl(m->fd, KDBUS_CMD_MEMFD_SIZE_SET, &sz);
+ r = ftruncate(m->fd, sz);
if (r < 0)
return -errno;
diff --git a/src/libsystemd/sd-bus/test-bus-memfd.c b/src/libsystemd/sd-bus/test-bus-memfd.c
deleted file mode 100644
index 3462732546..0000000000
--- a/src/libsystemd/sd-bus/test-bus-memfd.c
+++ /dev/null
@@ -1,180 +0,0 @@
-/*-*- 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 <sys/mman.h>
-#include <sys/uio.h>
-
-#include "log.h"
-#include "macro.h"
-#include "util.h"
-
-#include "sd-memfd.h"
-
-int main(int argc, char *argv[]) {
- sd_memfd *m;
- char *s, *name;
- uint64_t sz;
- int r, fd;
- FILE *f = NULL;
- char buf[3] = {};
- struct iovec iov[3] = {};
- char bufv[3][3] = {};
-
- log_set_max_level(LOG_DEBUG);
-
- r = sd_memfd_new(&m, NULL);
- if (r == -ENOENT)
- return EXIT_TEST_SKIP;
-
- assert_se(r >= 0);
-
- assert_se(sd_memfd_get_name(m, &name) >= 0);
- log_info("name: %s", name);
- free(name);
-
- r = sd_memfd_map(m, 0, 12, (void**) &s);
- assert_se(r >= 0);
-
- strcpy(s, "----- world");
-
- r = sd_memfd_set_sealed(m, 1);
- assert_se(r == -ETXTBSY);
-
- assert_se(write(sd_memfd_get_fd(m), "he", 2) == 2);
- assert_se(write(sd_memfd_get_fd(m), "XXX", 3) == 3);
- assert_se(streq(s, "heXXX world"));
-
- /* fix "hello" */
- assert_se(lseek(sd_memfd_get_fd(m), 2, SEEK_SET) == 2);
- assert_se(write(sd_memfd_get_fd(m), "ll", 2) == 2);
-
- assert_se(sd_memfd_get_file(m, &f) >= 0);
- fputc('o', f);
- fflush(f);
-
- /* check content */
- assert_se(streq(s, "hello world"));
-
- assert_se(munmap(s, 12) == 0);
-
- r = sd_memfd_get_sealed(m);
- assert_se(r == 0);
-
- r = sd_memfd_get_size(m, &sz);
- assert_se(r >= 0);
- assert_se(sz = page_size());
-
- /* truncate it */
- r = sd_memfd_set_size(m, 6);
- assert_se(r >= 0);
-
- /* get back new value */
- r = sd_memfd_get_size(m, &sz);
- assert_se(r >= 0);
- assert_se(sz == 6);
-
- r = sd_memfd_set_sealed(m, 1);
- assert_se(r >= 0);
-
- r = sd_memfd_get_sealed(m);
- assert_se(r == 1);
-
- fd = sd_memfd_dup_fd(m);
- assert_se(fd >= 0);
-
- sd_memfd_free(m);
-
- /* new sd_memfd, same underlying memfd */
- r = sd_memfd_new_from_fd(&m, fd);
- assert_se(r >= 0);
-
- /* we did truncate it to 6 */
- r = sd_memfd_get_size(m, &sz);
- assert_se(r >= 0 && sz == 6);
-
- /* map it, check content */
- r = sd_memfd_map(m, 0, 12, (void **)&s);
- assert_se(r >= 0);
-
- /* we only see the truncated size */
- assert_se(streq(s, "hello "));
-
- /* it was already sealed */
- r = sd_memfd_set_sealed(m, 1);
- assert_se(r == -EALREADY);
-
- /* we cannot break the seal, it is mapped */
- r = sd_memfd_set_sealed(m, 0);
- assert_se(r == -ETXTBSY);
-
- /* unmap it; become the single owner */
- assert_se(munmap(s, 12) == 0);
-
- /* now we can do flip the sealing */
- r = sd_memfd_set_sealed(m, 0);
- assert_se(r == 0);
- r = sd_memfd_get_sealed(m);
- assert_se(r == 0);
-
- r = sd_memfd_set_sealed(m, 1);
- assert_se(r == 0);
- r = sd_memfd_get_sealed(m);
- assert_se(r == 1);
-
- r = sd_memfd_set_sealed(m, 0);
- assert_se(r == 0);
- r = sd_memfd_get_sealed(m);
- assert_se(r == 0);
-
- /* seek at 2, read() 2 bytes */
- assert_se(lseek(fd, 2, SEEK_SET) == 2);
- assert_se(read(fd, buf, 2) == 2);
-
- /* check content */
- assert_se(memcmp(buf, "ll", 2) == 0);
-
- /* writev it out*/
- iov[0].iov_base = (char *)"ABC";
- iov[0].iov_len = 3;
- iov[1].iov_base = (char *)"DEF";
- iov[1].iov_len = 3;
- iov[2].iov_base = (char *)"GHI";
- iov[2].iov_len = 3;
- assert_se(pwritev(fd, iov, 3, 0) == 9);
-
- /* readv it back */
- iov[0].iov_base = bufv[0];
- iov[0].iov_len = 3;
- iov[1].iov_base = bufv[1];
- iov[1].iov_len = 3;
- iov[2].iov_base = bufv[2];
- iov[2].iov_len = 3;
- assert_se(preadv(fd, iov, 3, 0) == 9);
-
- /* check content */
- assert_se(memcmp(bufv[0], "ABC", 3) == 0);
- assert_se(memcmp(bufv[1], "DEF", 3) == 0);
- assert_se(memcmp(bufv[2], "GHI", 3) == 0);
-
- sd_memfd_free(m);
-
- return 0;
-}
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