diff options
author | Daniel Mack <zonque@gmail.com> | 2014-05-13 01:28:09 +0200 |
---|---|---|
committer | Daniel Mack <zonque@gmail.com> | 2014-08-17 21:47:00 +0200 |
commit | a6082d778ee4b97ec3eb6d3266cefc024c5d60f7 (patch) | |
tree | 9384d75776ffb4b1352f623982464743b7ca5b84 /src/libsystemd/sd-bus | |
parent | a6a4f528899b1dab47408733b4a423c66ea40f7a (diff) |
kdbus: switch over to generic memfd implementation (ABI+API break)
Diffstat (limited to 'src/libsystemd/sd-bus')
-rw-r--r-- | src/libsystemd/sd-bus/PORTING-DBUS1 | 40 | ||||
-rw-r--r-- | src/libsystemd/sd-bus/bus-kernel.c | 21 | ||||
-rw-r--r-- | src/libsystemd/sd-bus/bus-message.c | 10 | ||||
-rw-r--r-- | src/libsystemd/sd-bus/kdbus.h | 51 | ||||
-rw-r--r-- | src/libsystemd/sd-bus/sd-memfd.c | 54 | ||||
-rw-r--r-- | src/libsystemd/sd-bus/test-bus-memfd.c | 180 |
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; -} |