diff options
Diffstat (limited to 'src/libsystemd-bus/bus-kernel.c')
| -rw-r--r-- | src/libsystemd-bus/bus-kernel.c | 618 |
1 files changed, 618 insertions, 0 deletions
diff --git a/src/libsystemd-bus/bus-kernel.c b/src/libsystemd-bus/bus-kernel.c new file mode 100644 index 0000000000..0762b7836f --- /dev/null +++ b/src/libsystemd-bus/bus-kernel.c @@ -0,0 +1,618 @@ +/*-*- 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/>. +***/ + +#ifdef HAVE_VALGRIND_MEMCHECK_H +#include <valgrind/memcheck.h> +#endif + +#include <fcntl.h> +#include <malloc.h> + +#include "util.h" + +#include "bus-internal.h" +#include "bus-message.h" +#include "bus-kernel.h" +#include "bus-bloom.h" + +#define KDBUS_ITEM_NEXT(item) \ + (typeof(item))(((uint8_t *)item) + ALIGN8((item)->size)) + +#define KDBUS_ITEM_FOREACH(item, head) \ + for (item = (head)->items; \ + (uint8_t *)(item) < (uint8_t *)(head) + (head)->size; \ + item = KDBUS_ITEM_NEXT(item)) + +#define KDBUS_ITEM_HEADER_SIZE offsetof(struct kdbus_item, data) +#define KDBUS_ITEM_SIZE(s) ALIGN8((s) + KDBUS_ITEM_HEADER_SIZE) + +static int parse_unique_name(const char *s, uint64_t *id) { + int r; + + assert(s); + assert(id); + + if (!startswith(s, ":1.")) + return 0; + + r = safe_atou64(s + 3, id); + if (r < 0) + return r; + + return 1; +} + +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 = (intptr_t) p; + (*d)->vec.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); + + *d = ALIGN8_PTR(*d); + + (*d)->size = offsetof(struct kdbus_item, str) + length + 1; + (*d)->type = KDBUS_MSG_DST_NAME; + memcpy((*d)->str, s, length + 1); + + *d = (struct kdbus_item *) ((uint8_t*) *d + (*d)->size); +} + +static void* append_bloom(struct kdbus_item **d, size_t length) { + void *r; + + assert(d); + + *d = ALIGN8_PTR(*d); + + (*d)->size = offsetof(struct kdbus_item, data) + length; + (*d)->type = KDBUS_MSG_BLOOM; + r = (*d)->data; + + *d = (struct kdbus_item *) ((uint8_t*) *d + (*d)->size); + + return r; +} + +static void append_fds(struct kdbus_item **d, const int fds[], unsigned n_fds) { + assert(d); + assert(fds); + assert(n_fds > 0); + + *d = ALIGN8_PTR(*d); + (*d)->size = offsetof(struct kdbus_item, fds) + sizeof(int) * n_fds; + (*d)->type = KDBUS_MSG_UNIX_FDS; + memcpy((*d)->fds, fds, sizeof(int) * n_fds); + + *d = (struct kdbus_item *) ((uint8_t*) *d + (*d)->size); +} + +static int bus_message_setup_bloom(sd_bus_message *m, void *bloom) { + unsigned i; + int r; + + assert(m); + assert(bloom); + + memset(bloom, 0, BLOOM_SIZE); + + bloom_add_pair(bloom, "message-type", bus_message_type_to_string(m->header->type)); + + if (m->interface) + bloom_add_pair(bloom, "interface", m->interface); + if (m->member) + bloom_add_pair(bloom, "member", m->member); + if (m->path) { + bloom_add_pair(bloom, "path", m->path); + bloom_add_prefixes(bloom, "path-slash-prefix", m->path, '/'); + } + + r = sd_bus_message_rewind(m, true); + if (r < 0) + return r; + + for (i = 0; i < 64; i++) { + char type; + const char *t; + char buf[sizeof("arg")-1 + 2 + sizeof("-slash-prefix")]; + char *e; + + r = sd_bus_message_peek_type(m, &type, NULL); + if (r < 0) + return r; + + if (type != SD_BUS_TYPE_STRING && + type != SD_BUS_TYPE_OBJECT_PATH && + type != SD_BUS_TYPE_SIGNATURE) + break; + + r = sd_bus_message_read_basic(m, type, &t); + if (r < 0) + return r; + + e = stpcpy(buf, "arg"); + if (i < 10) + *(e++) = '0' + i; + else { + *(e++) = '0' + (i / 10); + *(e++) = '0' + (i % 10); + } + + *e = 0; + bloom_add_pair(bloom, buf, t); + + strcpy(e, "-dot-prefix"); + bloom_add_prefixes(bloom, buf, t, '.'); + strcpy(e, "-slash-prefix"); + bloom_add_prefixes(bloom, buf, t, '/'); + } + + return 0; +} + +static int bus_message_setup_kmsg(sd_bus *b, sd_bus_message *m) { + struct kdbus_item *d; + bool well_known; + uint64_t unique; + size_t sz, dl; + int r; + + assert(b); + assert(m); + assert(m->sealed); + + if (m->kdbus) + return 0; + + if (m->destination) { + r = parse_unique_name(m->destination, &unique); + if (r < 0) + return r; + + well_known = r == 0; + } else + well_known = false; + + sz = offsetof(struct kdbus_msg, items); + + /* Add in fixed header, fields header and payload */ + sz += 3 * ALIGN8(offsetof(struct kdbus_item, vec) + sizeof(struct kdbus_vec)); + + /* Add space for bloom filter */ + sz += ALIGN8(offsetof(struct kdbus_item, data) + BLOOM_SIZE); + + /* Add in well-known destination header */ + if (well_known) { + dl = strlen(m->destination); + sz += ALIGN8(offsetof(struct kdbus_item, str) + dl + 1); + } + + /* Add space for unix fds */ + if (m->n_fds > 0) + sz += ALIGN8(offsetof(struct kdbus_item, fds) + sizeof(int)*m->n_fds); + + m->kdbus = memalign(8, sz); + if (!m->kdbus) + return -ENOMEM; + + memset(m->kdbus, 0, sz); + + m->kdbus->flags = + ((m->header->flags & SD_BUS_MESSAGE_NO_REPLY_EXPECTED) ? 0 : KDBUS_MSG_FLAGS_EXPECT_REPLY) | + ((m->header->flags & SD_BUS_MESSAGE_NO_AUTO_START) ? KDBUS_MSG_FLAGS_NO_AUTO_START : 0); + m->kdbus->dst_id = + well_known ? 0 : + m->destination ? unique : KDBUS_DST_ID_BROADCAST; + m->kdbus->payload_type = KDBUS_PAYLOAD_DBUS1; + m->kdbus->cookie = m->header->serial; + + m->kdbus->timeout_ns = m->timeout * NSEC_PER_USEC; + + d = m->kdbus->items; + + if (well_known) + append_destination(&d, m->destination, dl); + + append_payload_vec(&d, m->header, sizeof(*m->header)); + + if (m->fields) + append_payload_vec(&d, m->fields, ALIGN8(m->header->fields_size)); + + if (m->body) + append_payload_vec(&d, m->body, m->header->body_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 (m->n_fds > 0) + append_fds(&d, m->fds, m->n_fds); + + m->kdbus->size = (uint8_t*) d - (uint8_t*) m->kdbus; + assert(m->kdbus->size <= sz); + + m->free_kdbus = true; + + return 0; +} + +int bus_kernel_take_fd(sd_bus *b) { + struct kdbus_cmd_hello hello = { + .conn_flags = + KDBUS_HELLO_ACCEPT_FD| + KDBUS_HELLO_ATTACH_COMM| + KDBUS_HELLO_ATTACH_EXE| + KDBUS_HELLO_ATTACH_CMDLINE| + KDBUS_HELLO_ATTACH_CGROUP| + KDBUS_HELLO_ATTACH_CAPS| + KDBUS_HELLO_ATTACH_SECLABEL| + KDBUS_HELLO_ATTACH_AUDIT + }; + int r; + + assert(b); + + if (b->is_server) + return -EINVAL; + + r = ioctl(b->input_fd, KDBUS_CMD_HELLO, &hello); + if (r < 0) + return -errno; + + /* The higher 32bit of both flags fields are considered + * 'incompatible flags'. Refuse them all for now. */ + if (hello.bus_flags > 0xFFFFFFFFULL || + hello.conn_flags > 0xFFFFFFFFULL) + return -ENOTSUP; + + if (hello.bloom_size != BLOOM_SIZE) + return -ENOTSUP; + + if (asprintf(&b->unique_name, ":1.%llu", (unsigned long long) hello.id) < 0) + return -ENOMEM; + + b->is_kernel = true; + b->bus_client = true; + b->can_fds = true; + + r = bus_start_running(b); + if (r < 0) + return r; + + return 1; +} + +int bus_kernel_connect(sd_bus *b) { + assert(b); + assert(b->input_fd < 0); + assert(b->output_fd < 0); + assert(b->kernel); + + if (b->is_server) + return -EINVAL; + + b->input_fd = open(b->kernel, O_RDWR|O_NOCTTY|O_CLOEXEC); + if (b->input_fd < 0) + return -errno; + + b->output_fd = b->input_fd; + + return bus_kernel_take_fd(b); +} + +int bus_kernel_write_message(sd_bus *bus, sd_bus_message *m) { + int r; + + assert(bus); + assert(m); + assert(bus->state == BUS_RUNNING); + + r = bus_message_setup_kmsg(bus, m); + if (r < 0) + return r; + + r = ioctl(bus->output_fd, KDBUS_CMD_MSG_SEND, m->kdbus); + if (r < 0) + return errno == EAGAIN ? 0 : -errno; + + return 1; +} + +static void close_kdbus_msg(struct kdbus_msg *k) { + struct kdbus_item *d; + + KDBUS_ITEM_FOREACH(d, k) { + + if (d->type != KDBUS_MSG_UNIX_FDS) + continue; + + close_many(d->fds, (d->size - offsetof(struct kdbus_item, fds)) / sizeof(int)); + } +} + +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; + _cleanup_free_ int *fds = NULL; + struct bus_header *h = NULL; + size_t total, n_bytes = 0, idx = 0; + const char *destination = NULL, *seclabel = NULL; + int r; + + assert(bus); + assert(k); + assert(ret); + + if (k->payload_type != KDBUS_PAYLOAD_DBUS1) + return 0; + + KDBUS_ITEM_FOREACH(d, k) { + size_t l; + + l = d->size - offsetof(struct kdbus_item, data); + + if (d->type == KDBUS_MSG_PAYLOAD) { + + if (!h) { + if (l < sizeof(struct bus_header)) + return -EBADMSG; + + h = (struct bus_header*) d->data; + } + + n_payload++; + n_bytes += l; + + } else if (d->type == KDBUS_MSG_UNIX_FDS) { + int *f; + unsigned j; + + j = l / sizeof(int); + f = realloc(fds, sizeof(int) * (n_fds + j)); + if (!f) + return -ENOMEM; + + fds = f; + 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) + seclabel = d->str; + } + + if (!h) + return -EBADMSG; + + r = bus_header_size(h, &total); + if (r < 0) + return r; + + if (n_bytes != total) + return -EBADMSG; + + r = bus_message_from_header(h, sizeof(struct bus_header), fds, n_fds, NULL, seclabel, 0, &m); + if (r < 0) + return r; + + KDBUS_ITEM_FOREACH(d, k) { + size_t l; + + l = d->size - offsetof(struct kdbus_item, data); + + if (d->type == KDBUS_MSG_PAYLOAD) { + + if (idx == sizeof(struct bus_header) && + l == ALIGN8(BUS_MESSAGE_FIELDS_SIZE(m))) + m->fields = d->data; + else if (idx == sizeof(struct bus_header) + ALIGN8(BUS_MESSAGE_FIELDS_SIZE(m)) && + l == BUS_MESSAGE_BODY_SIZE(m)) + m->body = d->data; + else if (!(idx == 0 && l == sizeof(struct bus_header))) { + sd_bus_message_unref(m); + return -EBADMSG; + } + + idx += l; + } else if (d->type == KDBUS_MSG_SRC_CREDS) { + m->pid_starttime = d->creds.starttime / NSEC_PER_USEC; + m->uid = d->creds.uid; + m->gid = d->creds.gid; + m->pid = d->creds.pid; + m->tid = d->creds.tid; + m->uid_valid = m->gid_valid = true; + } else if (d->type == KDBUS_MSG_TIMESTAMP) { + m->realtime = d->timestamp.realtime_ns / NSEC_PER_USEC; + m->monotonic = d->timestamp.monotonic_ns / NSEC_PER_USEC; + } else if (d->type == KDBUS_MSG_SRC_PID_COMM) + m->comm = d->str; + else if (d->type == KDBUS_MSG_SRC_TID_COMM) + m->tid_comm = d->str; + else if (d->type == KDBUS_MSG_SRC_EXE) + m->exe = d->str; + else if (d->type == KDBUS_MSG_SRC_CMDLINE) { + m->cmdline = d->str; + m->cmdline_length = l; + } else if (d->type == KDBUS_MSG_SRC_CGROUP) + m->cgroup = d->str; + else if (d->type == KDBUS_MSG_SRC_AUDIT) + m->audit = &d->audit; + else if (d->type == KDBUS_MSG_SRC_CAPS) { + m->capability = d->data; + m->capability_size = l; + } else + 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 (k->src_id == KDBUS_SRC_ID_KERNEL) + m->sender = "org.freedesktop.DBus"; + else { + snprintf(m->sender_buffer, sizeof(m->sender_buffer), ":1.%llu", (unsigned long long) k->src_id); + m->sender = m->sender_buffer; + } + + if (!m->destination) { + if (destination) + m->destination = destination; + else if (k->dst_id != KDBUS_DST_ID_WELL_KNOWN_NAME && + k->dst_id != KDBUS_DST_ID_BROADCAST) { + snprintf(m->destination_buffer, sizeof(m->destination_buffer), ":1.%llu", (unsigned long long) k->dst_id); + m->destination = m->destination_buffer; + } + } + + /* We take possession of the kmsg struct now */ + m->kdbus = k; + m->free_kdbus = true; + m->free_fds = true; + + fds = NULL; + + *ret = m; + return 1; +} + +int bus_kernel_read_message(sd_bus *bus, sd_bus_message **m) { + struct kdbus_msg *k; + size_t sz = 1024; + int r; + + assert(bus); + assert(m); + + for (;;) { + void *q; + + q = memalign(8, sz); + if (!q) + return -errno; + + free(bus->rbuffer); + k = bus->rbuffer = q; + k->size = sz; + + /* 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 = ioctl(bus->input_fd, KDBUS_CMD_MSG_RECV, bus->rbuffer); + if (r >= 0) + break; + + if (errno == EAGAIN) + return 0; + + if (errno != ENOBUFS) + return -errno; + + sz *= 2; + } + + r = bus_kernel_make_message(bus, k, m); + if (r > 0) + bus->rbuffer = NULL; + else + close_kdbus_msg(k); + + return r < 0 ? r : 1; +} + +int bus_kernel_create(const char *name, char **s) { + struct kdbus_cmd_bus_make *make; + struct kdbus_item *n, *cg; + size_t l; + int fd; + char *p; + + assert(name); + assert(s); + + fd = open("/dev/kdbus/control", O_RDWR|O_NOCTTY|O_CLOEXEC); + if (fd < 0) + return -errno; + + l = strlen(name); + make = alloca0(offsetof(struct kdbus_cmd_bus_make, items) + + KDBUS_ITEM_HEADER_SIZE + sizeof(uint64_t) + + KDBUS_ITEM_HEADER_SIZE + DECIMAL_STR_MAX(uid_t) + 1 + l + 1); + + cg = make->items; + cg->type = KDBUS_MAKE_CGROUP; + cg->data64[0] = 1; + cg->size = KDBUS_ITEM_HEADER_SIZE + sizeof(uint64_t); + + n = KDBUS_ITEM_NEXT(cg); + n->type = KDBUS_MAKE_NAME; + sprintf(n->str, "%lu-%s", (unsigned long) getuid(), name); + n->size = KDBUS_ITEM_HEADER_SIZE + strlen(n->str) + 1; + + make->size = offsetof(struct kdbus_cmd_bus_make, items) + cg->size + n->size; + make->flags = KDBUS_MAKE_ACCESS_WORLD | KDBUS_MAKE_POLICY_OPEN; + make->bus_flags = 0; + make->bloom_size = BLOOM_SIZE; + assert_cc(BLOOM_SIZE % 8 == 0); + + p = strjoin("/dev/kdbus/", n->str, "/bus", NULL); + if (!p) + return -ENOMEM; + + if (ioctl(fd, KDBUS_CMD_BUS_MAKE, make) < 0) { + close_nointr_nofail(fd); + free(p); + return -errno; + } + + if (s) + *s = p; + + return fd; +} |