diff options
Diffstat (limited to 'src/libsystemd-bus/bus-kernel.c')
| -rw-r--r-- | src/libsystemd-bus/bus-kernel.c | 388 |
1 files changed, 388 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..c10fcc54df --- /dev/null +++ b/src/libsystemd-bus/bus-kernel.c @@ -0,0 +1,388 @@ +/*-*- 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 "util.h" + +#include "bus-internal.h" +#include "bus-message.h" +#include "bus-kernel.h" + +#define KDBUS_MSG_FOREACH_DATA(d, k) \ + for ((d) = (k)->data; \ + (uint8_t*) (d) < (uint8_t*) (k) + (k)->size; \ + (d) = (struct kdbus_msg_data*) ((uint8_t*) (d) + ALIGN8((d)->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_msg_data **d, const void *p, size_t sz) { + assert(d); + assert(p); + assert(sz > 0); + + (*d)->size = offsetof(struct kdbus_msg_data, vec) + sizeof(struct kdbus_vec); + (*d)->type = KDBUS_MSG_PAYLOAD_VEC; + (*d)->vec.address = (uint64_t) p; + (*d)->vec.size = sz; + + *d = (struct kdbus_msg_data*) ((uint8_t*) *d + ALIGN8((*d)->size)); +} + +static void append_destination(struct kdbus_msg_data **d, const char *s, size_t length) { + assert(d); + assert(d); + + (*d)->size = offsetof(struct kdbus_msg_data, data) + length + 1; + (*d)->type = KDBUS_MSG_DST_NAME; + memcpy((*d)->data, s, length + 1); + + *d = (struct kdbus_msg_data*) ((uint8_t*) *d + ALIGN8((*d)->size)); +} + +static int bus_message_setup_kmsg(sd_bus_message *m) { + struct kdbus_msg_data *d; + bool well_known; + uint64_t unique; + size_t sz, dl; + int r; + + assert(m); + assert(m->sealed); + assert(!m->kdbus); + + 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, data); + + /* Add in fixed header, fields header, fields header padding and payload */ + sz += 4 * ALIGN8(offsetof(struct kdbus_msg_data, vec) + sizeof(struct kdbus_vec)); + + /* Add in well-known destination header */ + if (well_known) { + dl = strlen(m->destination); + sz += ALIGN8(offsetof(struct kdbus_msg, data) + dl + 1); + } + + m->kdbus = malloc0(sz); + if (!m->kdbus) + return -ENOMEM; + + 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 : (uint64_t) -1; + 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->data; + + 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, m->header->fields_size); + + if (m->header->fields_size % 8 != 0) { + static const uint8_t padding[7] = {}; + + append_payload_vec(&d, padding, 8 - (m->header->fields_size % 8)); + } + } + + if (m->body) + append_payload_vec(&d, m->body, m->header->body_size); + + m->kdbus->size = (uint8_t*) m - (uint8_t*) m->kdbus; + assert(m->kdbus->size <= sz); + + return 0; +} + +int bus_kernel_take_fd(sd_bus *b) { + struct kdbus_cmd_hello hello = {}; + int r; + + assert(b); + + r = ioctl(b->input_fd, KDBUS_CMD_HELLO, &hello); + if (r < 0) + return -errno; + + b->is_kernel = 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); + + b->input_fd = open(b->kernel, O_RDWR|O_NOCTTY|O_CLOEXEC); + if (b->input_fd) + 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(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 0; +} + +static void close_kdbus_msg(struct kdbus_msg *k) { + struct kdbus_msg_data *d; + + KDBUS_MSG_FOREACH_DATA(d, k) { + + if (d->type != KDBUS_MSG_UNIX_FDS) + continue; + + close_many(d->fds, (d->size - offsetof(struct kdbus_msg_data, 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_msg_data *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; + int r; + + assert(bus); + assert(k); + assert(ret); + + if (k->payload_type != KDBUS_PAYLOAD_DBUS1) + return 0; + + KDBUS_MSG_FOREACH_DATA(d, k) { + size_t l; + + l = d->size - offsetof(struct kdbus_msg_data, 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, j); + n_fds += j; + } + } + + 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, NULL, 0, &m); + if (r < 0) + return r; + + KDBUS_MSG_FOREACH_DATA(d, k) { + size_t l; + + if (d->type != KDBUS_MSG_PAYLOAD) + continue; + + l = d->size - offsetof(struct kdbus_msg_data, data); + + if (idx == sizeof(struct bus_header) && + l == 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 { + sd_bus_message_unref(m); + return -EBADMSG; + } + + idx += l; + } + + r = bus_message_parse_fields(m); + if (r < 0) { + sd_bus_message_unref(m); + return r; + } + + /* 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 = 128; + int r; + + assert(bus); + assert(m); + + for (;;) { + void *q; + + q = realloc(bus->rbuffer, sz); + if (!q) + return -errno; + + k = bus->rbuffer = q; + k->size = sz; + + r = ioctl(bus->input_fd, KDBUS_CMD_MSG_RECV, bus->rbuffer); + if (r >= 0) + break; + + if (errno == EAGAIN) + return 0; + + if (errno != -EMSGSIZE) + 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; +} + +int bus_kernel_create(const char *name, char **s) { + struct kdbus_cmd_fname *fname; + 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); + fname = alloca(offsetof(struct kdbus_cmd_fname, name) + DECIMAL_STR_MAX(uid_t) + 1 + l + 1); + sprintf(fname->name, "%lu-%s", (unsigned long) getuid(), name); + fname->size = offsetof(struct kdbus_cmd_fname, name) + strlen(fname->name) + 1; + fname->kernel_flags = KDBUS_CMD_FNAME_ACCESS_WORLD; + fname->user_flags = 0; + + p = strjoin("/dev/kdbus/", fname->name, "/bus", NULL); + if (!p) + return -ENOMEM; + + if (ioctl(fd, KDBUS_CMD_BUS_MAKE, &fname) < 0) { + close_nointr_nofail(fd); + free(p); + return -errno; + } + + if (s) + *s = p; + + return fd; +} |