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bus: implement support for FD passing

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This commit is contained in:
Lennart Poettering 2013-03-24 22:02:05 +01:00
parent 3f95f83c54
commit 2c93b4efec
8 changed files with 291 additions and 44 deletions
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5
src/libsystemd-bus/bus-internal.h
View File

@ -114,6 +114,9 @@ struct sd_bus {
struct ucred ucred;
char label[NAME_MAX];
int *fds;
unsigned n_fds;
};
static inline void bus_unrefp(sd_bus **b) {
@ -137,6 +140,8 @@ static inline void bus_unrefp(sd_bus **b) {
* bytes */
#define BUS_ARRAY_MAX_SIZE 67108864
#define BUS_FDS_MAX 1024
bool object_path_is_valid(const char *p);
bool interface_name_is_valid(const char *p);
bool service_name_is_valid(const char *p);

190
src/libsystemd-bus/bus-message.c
View File

@ -20,6 +20,7 @@
***/
#include <errno.h>
#include <fcntl.h>
#include "util.h"
#include "utf8.h"
@ -50,8 +51,6 @@ static void reset_containers(sd_bus_message *m) {
}
static void message_free(sd_bus_message *m) {
unsigned i;
assert(m);
if (m->free_header)
@ -63,8 +62,10 @@ static void message_free(sd_bus_message *m) {
if (m->free_body)
free(m->body);
for (i = 0; i < m->n_fds; i++)
close_nointr_nofail(m->fds[i]);
if (m->free_fds) {
close_many(m->fds, m->n_fds);
free(m->fds);
}
reset_containers(m);
free(m->root_container.signature);
@ -227,7 +228,9 @@ static int message_append_field_uint32(sd_bus_message *m, uint8_t h, uint32_t x)
int bus_message_from_malloc(
void *buffer,
size_t length,
struct ucred *ucred,
int *fds,
unsigned n_fds,
const struct ucred *ucred,
const char *label,
sd_bus_message **ret) {
@ -237,6 +240,7 @@ int bus_message_from_malloc(
int r;
assert(buffer || length <= 0);
assert(fds || n_fds <= 0);
assert(ret);
if (length < sizeof(struct bus_header))
@ -276,11 +280,12 @@ int bus_message_from_malloc(
return -ENOMEM;
m->n_ref = 1;
m->sealed = true;
m->header = h;
m->free_header = true;
m->fields = (uint8_t*) buffer + sizeof(struct bus_header);
m->body = (uint8_t*) buffer + sizeof(struct bus_header) + ALIGN_TO(fs, 8);
m->sealed = true;
m->fds = fds;
m->n_fds = n_fds;
if (ucred) {
m->uid = ucred->uid;
@ -299,13 +304,19 @@ int bus_message_from_malloc(
m->iovec[0].iov_len = length;
r = message_parse_fields(m);
if (r < 0) {
message_free(m);
return r;
}
if (r < 0)
goto fail;
/* We take possession of the memory and fds now */
m->free_header = true;
m->free_fds = true;
*ret = m;
return 0;
fail:
message_free(m);
return r;
}
static sd_bus_message *message_new(sd_bus *bus, uint8_t type) {
@ -320,6 +331,7 @@ static sd_bus_message *message_new(sd_bus *bus, uint8_t type) {
m->header->endian = SD_BUS_NATIVE_ENDIAN;
m->header->type = type;
m->header->version = bus ? bus->message_version : 1;
m->allow_fds = !bus || bus->can_fds;
return m;
}
@ -770,9 +782,14 @@ int message_append_basic(sd_bus_message *m, char type, const void *p, const void
uint32_t k;
void *a;
char *e = NULL;
int fd = -1;
uint32_t fdi;
int r;
if (!m)
return -EINVAL;
if (!p)
return -EINVAL;
if (m->sealed)
return -EPERM;
if (!bus_type_is_basic(type))
@ -800,26 +817,12 @@ int message_append_basic(sd_bus_message *m, char type, const void *p, const void
case SD_BUS_TYPE_STRING:
case SD_BUS_TYPE_OBJECT_PATH:
if (!p) {
if (e)
c->signature[c->index] = 0;
return -EINVAL;
}
align = 4;
sz = 4 + strlen(p) + 1;
break;
case SD_BUS_TYPE_SIGNATURE:
if (!p) {
if (e)
c->signature[c->index] = 0;
return -EINVAL;
}
align = 1;
sz = 1 + strlen(p) + 1;
break;
@ -833,6 +836,41 @@ int message_append_basic(sd_bus_message *m, char type, const void *p, const void
p = &k;
break;
case SD_BUS_TYPE_UNIX_FD: {
int z, *f;
if (!m->allow_fds) {
r = -ENOTSUP;
goto fail;
}
align = sz = 4;
z = *(int*) p;
if (z < 0) {
r = -EINVAL;
goto fail;
}
fd = fcntl(z, F_DUPFD_CLOEXEC, 3);
if (fd < 0) {
r = -errno;
goto fail;
}
f = realloc(m->fds, sizeof(int) * (m->n_fds + 1));
if (!f) {
r = -ENOMEM;
goto fail;
}
fdi = m->n_fds;
f[fdi] = fd;
m->fds = f;
m->free_fds = true;
break;
}
default:
align = bus_type_get_alignment(type);
sz = bus_type_get_size(type);
@ -844,11 +882,8 @@ int message_append_basic(sd_bus_message *m, char type, const void *p, const void
a = message_extend_body(m, align, sz);
if (!a) {
/* Truncate extended signature again */
if (e)
c->signature[c->index] = 0;
return -ENOMEM;
r = -ENOMEM;
goto fail;
}
if (type == SD_BUS_TYPE_STRING || type == SD_BUS_TYPE_OBJECT_PATH) {
@ -864,6 +899,13 @@ int message_append_basic(sd_bus_message *m, char type, const void *p, const void
if (stored)
*stored = (const uint8_t*) a + 1;
} else if (type == SD_BUS_TYPE_UNIX_FD) {
*(uint32_t*) a = fdi;
if (stored)
*stored = a;
m->n_fds ++;
} else {
memcpy(a, p, sz);
@ -876,6 +918,16 @@ int message_append_basic(sd_bus_message *m, char type, const void *p, const void
c->index++;
return 0;
fail:
/* Truncate extended signature again */
if (e)
c->signature[c->index] = 0;
if (fd >= 0)
close_nointr_nofail(fd);
return r;
}
int sd_bus_message_append_basic(sd_bus_message *m, char type, const void *p) {
@ -1464,6 +1516,8 @@ int sd_bus_message_read_basic(sd_bus_message *m, char type, void *p) {
return -EPERM;
if (!bus_type_is_basic(type))
return -EINVAL;
if (!p)
return -EINVAL;
c = message_get_container(m);
@ -1530,12 +1584,13 @@ int sd_bus_message_read_basic(sd_bus_message *m, char type, void *p) {
}
default: {
size_t sz, align;
size_t sz, align, rindex;
align = bus_type_get_alignment(type);
sz = bus_type_get_size(type);
r = message_peek_body(m, &m->rindex, align, sz, &q);
rindex = m->rindex;
r = message_peek_body(m, &rindex, align, sz, &q);
if (r <= 0)
return r;
@ -1565,10 +1620,28 @@ int sd_bus_message_read_basic(sd_bus_message *m, char type, void *p) {
*(uint64_t*) p = BUS_MESSAGE_BSWAP64(m, *(uint64_t*) q);
break;
case SD_BUS_TYPE_UNIX_FD: {
int copy;
uint32_t j;
j = BUS_MESSAGE_BSWAP32(m, *(uint32_t*) q);
if (j >= m->n_fds)
return -EBADMSG;
copy = fcntl(m->fds[j], F_DUPFD_CLOEXEC, 3);
if (copy < 0)
return -errno;
*(int*) p = copy;
break;
}
default:
assert_not_reached("Unknown basic type...");
}
m->rindex = rindex;
break;
}
}
@ -2028,7 +2101,8 @@ static int message_read_ap(sd_bus_message *m, const char *types, va_list ap) {
case SD_BUS_TYPE_DOUBLE:
case SD_BUS_TYPE_STRING:
case SD_BUS_TYPE_OBJECT_PATH:
case SD_BUS_TYPE_SIGNATURE: {
case SD_BUS_TYPE_SIGNATURE:
case SD_BUS_TYPE_UNIX_FD: {
void *p;
p = va_arg(ap, void*);
@ -2399,6 +2473,7 @@ static int message_skip_fields(
static int message_parse_fields(sd_bus_message *m) {
size_t ri;
int r;
uint32_t unix_fds = 0;
assert(m);
@ -2419,6 +2494,10 @@ static int message_parse_fields(sd_bus_message *m) {
return -EBADMSG;
case SD_BUS_MESSAGE_HEADER_PATH:
if (m->path)
return -EBADMSG;
if (!streq(signature, "o"))
return -EBADMSG;
@ -2426,6 +2505,10 @@ static int message_parse_fields(sd_bus_message *m) {
break;
case SD_BUS_MESSAGE_HEADER_INTERFACE:
if (m->interface)
return -EBADMSG;
if (!streq(signature, "s"))
return -EBADMSG;
@ -2433,6 +2516,10 @@ static int message_parse_fields(sd_bus_message *m) {
break;
case SD_BUS_MESSAGE_HEADER_MEMBER:
if (m->member)
return -EBADMSG;
if (!streq(signature, "s"))
return -EBADMSG;
@ -2440,6 +2527,10 @@ static int message_parse_fields(sd_bus_message *m) {
break;
case SD_BUS_MESSAGE_HEADER_ERROR_NAME:
if (m->error.name)
return -EBADMSG;
if (!streq(signature, "s"))
return -EBADMSG;
@ -2447,6 +2538,10 @@ static int message_parse_fields(sd_bus_message *m) {
break;
case SD_BUS_MESSAGE_HEADER_DESTINATION:
if (m->destination)
return -EBADMSG;
if (!streq(signature, "s"))
return -EBADMSG;
@ -2454,6 +2549,10 @@ static int message_parse_fields(sd_bus_message *m) {
break;
case SD_BUS_MESSAGE_HEADER_SENDER:
if (m->sender)
return -EBADMSG;
if (!streq(signature, "s"))
return -EBADMSG;
@ -2465,6 +2564,9 @@ static int message_parse_fields(sd_bus_message *m) {
const char *s;
char *c;
if (m->root_container.signature)
return -EBADMSG;
if (!streq(signature, "g"))
return -EBADMSG;
@ -2482,6 +2584,9 @@ static int message_parse_fields(sd_bus_message *m) {
}
case SD_BUS_MESSAGE_HEADER_REPLY_SERIAL:
if (m->reply_serial != 0)
return -EBADMSG;
if (!streq(signature, "u"))
return -EBADMSG;
@ -2494,6 +2599,22 @@ static int message_parse_fields(sd_bus_message *m) {
break;
case SD_BUS_MESSAGE_HEADER_UNIX_FDS:
if (unix_fds != 0)
return -EBADMSG;
if (!streq(signature, "u"))
return -EBADMSG;
r = message_peek_field_uint32(m, &ri, &unix_fds);
if (r < 0)
return -EBADMSG;
if (unix_fds == 0)
return -EBADMSG;
break;
default:
r = message_skip_fields(m, &ri, (uint32_t) -1, (const char **) &signature);
}
@ -2502,6 +2623,9 @@ static int message_parse_fields(sd_bus_message *m) {
return r;
}
if (m->n_fds != unix_fds)
return -EBADMSG;
if (isempty(m->root_container.signature) != (BUS_MESSAGE_BODY_SIZE(m) == 0))
return -EBADMSG;

14
src/libsystemd-bus/bus-message.h
View File

@ -67,12 +67,14 @@ struct sd_bus_message {
pid_t tid;
bool sealed:1;
bool dont_send:1;
bool allow_fds:1;
bool uid_valid:1;
bool gid_valid:1;
bool free_header:1;
bool free_fields:1;
bool free_body:1;
bool dont_send:1;
bool free_fds:1;
struct bus_header *header;
void *fields;
@ -130,5 +132,13 @@ static inline void bus_message_unrefp(sd_bus_message **m) {
int bus_message_seal(sd_bus_message *m, uint64_t serial);
int bus_message_dump(sd_bus_message *m);
int bus_message_get_blob(sd_bus_message *m, void **buffer, size_t *sz);
int bus_message_from_malloc(void *buffer, size_t length, struct ucred *ucred, const char *label, sd_bus_message **ret);
int bus_message_read_strv_extend(sd_bus_message *m, char ***l);
int bus_message_from_malloc(
void *buffer,
size_t length,
int *fds,
unsigned n_fds,
const struct ucred *ucred,
const char *label,
sd_bus_message **ret);

50
src/libsystemd-bus/sd-bus.c
View File

@ -53,6 +53,9 @@ static void bus_free(sd_bus *b) {
free(b->auth_uid);
free(b->address);
close_many(b->fds, b->n_fds);
free(b->fds);
for (i = 0; i < b->rqueue_size; i++)
sd_bus_message_unref(b->rqueue[i]);
free(b->rqueue);
@ -889,6 +892,18 @@ static int message_write(sd_bus *bus, sd_bus_message *m, size_t *idx) {
if (*idx >= m->size)
return 0;
zero(mh);
if (m->n_fds > 0) {
struct cmsghdr *control;
control = alloca(CMSG_SPACE(sizeof(int) * m->n_fds));
mh.msg_control = control;
control->cmsg_level = SOL_SOCKET;
control->cmsg_type = SCM_RIGHTS;
mh.msg_controllen = control->cmsg_len = CMSG_LEN(sizeof(int) * m->n_fds);
memcpy(CMSG_DATA(control), m->fds, sizeof(int) * m->n_fds);
}
n = m->n_iovec * sizeof(struct iovec);
iov = alloca(n);
@ -897,7 +912,6 @@ static int message_write(sd_bus *bus, sd_bus_message *m, size_t *idx) {
j = 0;
iovec_advance(iov, &j, *idx);
zero(mh);
mh.msg_iov = iov;
mh.msg_iovlen = m->n_iovec;
@ -963,7 +977,7 @@ static int message_read_need(sd_bus *bus, size_t *need) {
static int message_make(sd_bus *bus, size_t size, sd_bus_message **m) {
sd_bus_message *t;
void *b = NULL;
void *b;
int r;
assert(bus);
@ -976,11 +990,14 @@ static int message_make(sd_bus *bus, size_t size, sd_bus_message **m) {
bus->rbuffer_size - size);
if (!b)
return -ENOMEM;
}
} else
b = NULL;
r = bus_message_from_malloc(bus->rbuffer, size,
bus->fds, bus->n_fds,
bus->ucred_valid ? &bus->ucred : NULL,
bus->label[0] ? bus->label : NULL, &t);
bus->label[0] ? bus->label : NULL,
&t);
if (r < 0) {
free(b);
return r;
@ -989,6 +1006,9 @@ static int message_make(sd_bus *bus, size_t size, sd_bus_message **m) {
bus->rbuffer = b;
bus->rbuffer_size -= size;
bus->fds = NULL;
bus->n_fds = 0;
*m = t;
return 1;
}
@ -1002,7 +1022,8 @@ static int message_read(sd_bus *bus, sd_bus_message **m) {
void *b;
union {
struct cmsghdr cmsghdr;
uint8_t buf[CMSG_SPACE(sizeof(struct ucred)) +
uint8_t buf[CMSG_SPACE(sizeof(int) * BUS_FDS_MAX) +
CMSG_SPACE(sizeof(struct ucred)) +
CMSG_SPACE(NAME_MAX)]; /*selinux label */
} control;
struct cmsghdr *cmsg;
@ -1039,11 +1060,24 @@ static int message_read(sd_bus *bus, sd_bus_message **m) {
return errno == EAGAIN ? 0 : -errno;
bus->rbuffer_size += k;
bus->ucred_valid = false;
bus->label[0] = 0;
for (cmsg = CMSG_FIRSTHDR(&mh); cmsg; cmsg = CMSG_NXTHDR(&mh, cmsg)) {
if (cmsg->cmsg_level == SOL_SOCKET &&
cmsg->cmsg_type == SCM_RIGHTS) {
int n, *f;
n = (cmsg->cmsg_len - CMSG_LEN(0)) / sizeof(int);
f = realloc(bus->fds, sizeof(int) + (bus->n_fds + n));
if (!f) {
close_many((int*) CMSG_DATA(cmsg), n);
return -ENOMEM;
}
memcpy(f + bus->n_fds, CMSG_DATA(cmsg), n * sizeof(int));
bus->fds = f;
bus->n_fds += n;
} else if (cmsg->cmsg_level == SOL_SOCKET &&
cmsg->cmsg_type == SCM_CREDENTIALS &&
cmsg->cmsg_len == CMSG_LEN(sizeof(struct ucred))) {
@ -1157,6 +1191,8 @@ int sd_bus_send(sd_bus *bus, sd_bus_message *m, uint64_t *serial) {
return -ENOTCONN;
if (!m)
return -EINVAL;
if (m->n_fds > 0 && !bus->can_fds)
return -ENOTSUP;
/* If the serial number isn't kept, then we know that no reply
* is expected */

1
src/libsystemd-bus/sd-bus.h
View File

@ -28,7 +28,6 @@
#include "sd-bus-protocol.h"
/* TODO:
* - make unix fd passing work
* - implicitly add stub introspection calls
* - implement unix exec protocol
* - server side

71
src/libsystemd-bus/test-bus-chat.c
View File

@ -23,6 +23,7 @@
#include <stdlib.h>
#include <pthread.h>
#include <unistd.h>
#include <fcntl.h>
#include "log.h"
#include "util.h"
@ -202,6 +203,31 @@ static int server(sd_bus *bus) {
}
sleep(1);
} else if (sd_bus_message_is_method_call(m, "org.freedesktop.systemd.test", "FileDescriptor")) {
int fd;
static const char x = 'X';
r = sd_bus_message_read(m, "h", &fd);
if (r < 0) {
log_error("Failed to get parameter: %s", strerror(-r));
goto fail;
}
if (write(fd, &x, 1) < 0) {
log_error("Failed to write to fd: %m");
close_nointr_nofail(fd);
goto fail;
}
close_nointr_nofail(fd);
r = sd_bus_message_new_method_return(bus, m, &reply);
if (r < 0) {
log_error("Failed to allocate return: %s", strerror(-r));
goto fail;
}
} else if (sd_bus_message_is_method_call(m, NULL, NULL)) {
const sd_bus_error e = SD_BUS_ERROR_INIT_CONST("org.freedesktop.DBus.Error.UnknownMethod", "Unknown method.");
@ -242,6 +268,8 @@ static void* client1(void*p) {
sd_bus_error error = SD_BUS_ERROR_INIT;
const char *hello;
int r;
int pp[2] = { -1, -1 };
char x;
r = sd_bus_open_user(&bus);
if (r < 0) {
@ -281,6 +309,46 @@ static void* client1(void*p) {
assert(streq(hello, "hello"));
if (pipe2(pp, O_CLOEXEC|O_NONBLOCK) < 0) {
log_error("Failed to allocate pipe: %m");
r = -errno;
goto finish;
}
sd_bus_message_unref(m);
m = NULL;
r = sd_bus_message_new_method_call(
bus,
"org.freedesktop.systemd.test",
"/",
"org.freedesktop.systemd.test",
"FileDescriptor",
&m);
if (r < 0) {
log_error("Failed to allocate method call: %s", strerror(-r));
goto finish;
}
r = sd_bus_message_append(m, "h", pp[1]);
if (r < 0) {
log_error("Failed to append string: %s", strerror(-r));
goto finish;
}
sd_bus_message_unref(reply);
reply = NULL;
r = sd_bus_send_with_reply_and_block(bus, m, 0, &error, &reply);
if (r < 0) {
log_error("Failed to issue method call: %s", bus_error_message(&error, -r));
goto finish;
}
errno = 0;
if (read(pp[0], &x, 1) <= 0) {
log_error("Failed to read from pipe: %s", errno ? strerror(errno) : "early read");
goto finish;
}
r = 0;
finish:
@ -305,6 +373,9 @@ finish:
}
sd_bus_error_free(&error);
close_pipe(pp);
return INT_TO_PTR(r);
}

2
src/libsystemd-bus/test-bus-marshal.c
View File

@ -121,7 +121,7 @@ int main(int argc, char *argv[]) {
m = sd_bus_message_unref(m);
r = bus_message_from_malloc(buffer, sz, NULL, NULL, &m);
r = bus_message_from_malloc(buffer, sz, NULL, 0, NULL, NULL, &m);
assert_se(r >= 0);
bus_message_dump(m);

2
src/shared/util.c
View File

@ -219,6 +219,8 @@ void close_nointr_nofail(int fd) {
void close_many(const int fds[], unsigned n_fd) {
unsigned i;
assert(fds || n_fd <= 0);
for (i = 0; i < n_fd; i++)
close_nointr_nofail(fds[i]);
}