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bus: rework message struct to keep header with fields in same malloc() block

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This allows us to guarantee that the first payload_vec we pass to the
kernel for each message is guaranteed to include the full header and all
its field.
This commit is contained in:
Lennart Poettering
2013-05-15 02:56:45 +02:00
parent 9b29bb6853
commit c91cb83c4d
4 changed files with 92 additions and 126 deletions
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src/libsystemd-bus/bus-kernel.c
+9 -38
View File
@@ -211,7 +211,7 @@ static int bus_message_setup_kmsg(sd_bus *b, sd_bus_message *m) {
sz = offsetof(struct kdbus_msg, items);
/* Add in fixed header, fields header and payload */
sz += (1 + !!m->fields + m->n_body_parts) *
sz += (1 + m->n_body_parts) *
ALIGN8(offsetof(struct kdbus_item, vec) + sizeof(struct kdbus_vec));
/* Add space for bloom filter */
@@ -249,11 +249,7 @@ static int bus_message_setup_kmsg(sd_bus *b, sd_bus_message *m) {
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));
append_payload_vec(&d, m->header, BUS_MESSAGE_BODY_BEGIN(m));
MESSAGE_FOREACH_PART(part, i, m)
append_payload_vec(&d, part->data, part->size);
@@ -398,22 +394,6 @@ static void close_kdbus_msg(sd_bus *bus, struct kdbus_msg *k) {
}
}
static bool range_contains(
size_t astart, size_t asize,
size_t bstart, size_t bsize,
void *a, void **b) {
if (bstart < astart)
return false;
if (bstart + bsize > astart + asize)
return false;
*b = (uint8_t*) a + (bstart - astart);
return true;
}
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;
@@ -439,10 +419,10 @@ static int bus_kernel_make_message(sd_bus *bus, struct kdbus_msg *k, sd_bus_mess
if (d->type == KDBUS_MSG_PAYLOAD_VEC) {
if (!h) {
if (d->vec.size < sizeof(struct bus_header))
return -EBADMSG;
h = UINT64_TO_PTR(d->vec.address);
if (!bus_header_is_complete(h, d->vec.size))
return -EBADMSG;
}
n_payload++;
@@ -470,7 +450,7 @@ static int bus_kernel_make_message(sd_bus *bus, struct kdbus_msg *k, sd_bus_mess
if (!h)
return -EBADMSG;
r = bus_header_size(h, &total);
r = bus_header_message_size(h, &total);
if (r < 0)
return r;
@@ -489,11 +469,7 @@ static int bus_kernel_make_message(sd_bus *bus, struct kdbus_msg *k, sd_bus_mess
if (d->type == KDBUS_MSG_PAYLOAD_VEC) {
size_t begin_body;
/* Fill in fields material */
range_contains(idx, d->vec.size, ALIGN8(sizeof(struct bus_header)), BUS_MESSAGE_FIELDS_SIZE(m),
UINT64_TO_PTR(d->vec.address), &m->fields);
begin_body = ALIGN8(sizeof(struct bus_header)) + ALIGN8(BUS_MESSAGE_FIELDS_SIZE(m));
begin_body = BUS_MESSAGE_BODY_BEGIN(m);
if (idx + d->vec.size > begin_body) {
struct bus_body_part *part;
@@ -507,10 +483,10 @@ static int bus_kernel_make_message(sd_bus *bus, struct kdbus_msg *k, sd_bus_mess
}
if (idx >= begin_body) {
part->data = (void*) d->vec.address;
part->data = UINT64_TO_PTR(d->vec.address);
part->size = d->vec.size;
} else {
part->data = (uint8_t*) (uintptr_t) d->vec.address + (begin_body - idx);
part->data = (uint8_t*) UINT64_TO_PTR(d->vec.address) + (begin_body - idx);
part->size = d->vec.size - (begin_body - idx);
}
@@ -551,11 +527,6 @@ static int bus_kernel_make_message(sd_bus *bus, struct kdbus_msg *k, sd_bus_mess
log_debug("Got unknown field from kernel %llu", d->type);
}
if ((BUS_MESSAGE_FIELDS_SIZE(m) > 0 && !m->fields)) {
sd_bus_message_unref(m);
return -EBADMSG;
}
r = bus_message_parse_fields(m);
if (r < 0) {
sd_bus_message_unref(m);
src/libsystemd-bus/bus-message.c
+68 -76
View File
@@ -116,9 +116,6 @@ static void message_free(sd_bus_message *m) {
if (m->free_header)
free(m->header);
if (m->free_fields)
free(m->fields);
message_reset_parts(m);
if (m->free_kdbus)
@@ -151,66 +148,64 @@ static void message_free(sd_bus_message *m) {
free(m);
}
static void* buffer_extend(void **p, uint32_t *sz, size_t align, size_t extend) {
size_t start, end;
void *k;
assert(p);
assert(sz);
assert(align > 0);
start = ALIGN_TO((size_t) *sz, align);
end = start + extend;
if (end == *sz)
return (uint8_t*) *p + start;
if (end > (size_t) ((uint32_t) -1))
return NULL;
k = realloc(*p, end);
if (!k)
return NULL;
/* Zero out padding */
if (start > *sz)
memset((uint8_t*) k + *sz, 0, start - *sz);
*p = k;
*sz = end;
return (uint8_t*) k + start;
}
static void *message_extend_fields(sd_bus_message *m, size_t align, size_t sz) {
void *p, *op;
size_t os;
void *op, *np;
size_t old_size, new_size, start;
assert(m);
if (m->poisoned)
return NULL;
op = m->fields;
os = m->header->fields_size;
old_size = sizeof(struct bus_header) + m->header->fields_size;
start = ALIGN_TO(old_size, align);
new_size = start + sz;
p = buffer_extend(&m->fields, &m->header->fields_size, align, sz);
if (!p) {
m->poisoned = true;
return NULL;
if (old_size == new_size)
return (uint8_t*) m->header + old_size;
if (new_size > (size_t) ((uint32_t) -1))
goto poison;
if (m->free_header) {
np = realloc(m->header, ALIGN8(new_size));
if (!np)
goto poison;
} else {
/* Initially, the header is allocated as part of of
* the sd_bus_message itself, let's replace it by
* dynamic data */
np = malloc(ALIGN8(new_size));
if (!np)
goto poison;
memcpy(np, m->header, sizeof(struct bus_header));
}
/* Zero out padding */
if (start > old_size)
memset((uint8_t*) np + old_size, 0, start - old_size);
op = m->header;
m->header = np;
m->header->fields_size = new_size - sizeof(struct bus_header);
/* Adjust quick access pointers */
m->path = adjust_pointer(m->path, op, os, m->fields);
m->interface = adjust_pointer(m->interface, op, os, m->fields);
m->member = adjust_pointer(m->member, op, os, m->fields);
m->destination = adjust_pointer(m->destination, op, os, m->fields);
m->sender = adjust_pointer(m->sender, op, os, m->fields);
m->error.name = adjust_pointer(m->error.name, op, os, m->fields);
m->path = adjust_pointer(m->path, op, old_size, m->header);
m->interface = adjust_pointer(m->interface, op, old_size, m->header);
m->member = adjust_pointer(m->member, op, old_size, m->header);
m->destination = adjust_pointer(m->destination, op, old_size, m->header);
m->sender = adjust_pointer(m->sender, op, old_size, m->header);
m->error.name = adjust_pointer(m->error.name, op, old_size, m->header);
m->free_fields = true;
m->free_header = true;
return p;
return (uint8_t*) np + start;
poison:
m->poisoned = true;
return NULL;
}
static int message_append_field_string(
@@ -390,8 +385,6 @@ int bus_message_from_malloc(
goto fail;
}
m->fields = (uint8_t*) buffer + sizeof(struct bus_header);
m->n_body_parts = 1;
m->body.data = (uint8_t*) buffer + sizeof(struct bus_header) + ALIGN8(BUS_MESSAGE_FIELDS_SIZE(m));
m->body.size = length - sizeof(struct bus_header) - ALIGN8(BUS_MESSAGE_FIELDS_SIZE(m));
@@ -3132,7 +3125,7 @@ static int message_peek_fields(
assert(rindex);
assert(align > 0);
return buffer_peek(m->fields, BUS_MESSAGE_FIELDS_SIZE(m), rindex, align, nbytes, ret);
return buffer_peek(BUS_MESSAGE_FIELDS(m), BUS_MESSAGE_FIELDS_SIZE(m), rindex, align, nbytes, ret);
}
static int message_peek_field_uint32(
@@ -3584,21 +3577,13 @@ int bus_message_seal(sd_bus_message *m, uint64_t serial) {
return r;
}
/* Add padding at the end, since we know the body
* needs to start at an 8 byte alignment. */
l = BUS_MESSAGE_FIELDS_SIZE(m);
a = ALIGN8(l) - l;
if (a > 0) {
/* Add padding at the end, since we know the body
* needs to start at an 8 byte alignment. */
void *p;
p = message_extend_fields(m, 1, a);
if (!p)
return -ENOMEM;
memset(p, 0, a);
m->header->fields_size -= a;
}
if (a > 0)
memset((uint8_t*) BUS_MESSAGE_FIELDS(m) + l, 0, a);
MESSAGE_FOREACH_PART(part, i, m)
if (part->memfd >= 0 && !part->sealed) {
@@ -3899,15 +3884,7 @@ int bus_message_get_blob(sd_bus_message *m, void **buffer, size_t *sz) {
if (!p)
return -ENOMEM;
e = mempcpy(p, m->header, sizeof(*m->header));
if (m->fields) {
e = mempcpy(e, m->fields, m->header->fields_size);
if (m->header->fields_size % 8 != 0)
e = mempset(e, 0, 8 - (m->header->fields_size % 8));
}
e = mempcpy(p, m->header, BUS_MESSAGE_BODY_BEGIN(m));
MESSAGE_FOREACH_PART(part, i, m)
e = mempcpy(e, part->data, part->size);
@@ -3981,7 +3958,22 @@ const char* bus_message_get_arg(sd_bus_message *m, unsigned i) {
return t;
}
int bus_header_size(struct bus_header *h, size_t *sum) {
bool bus_header_is_complete(struct bus_header *h, size_t size) {
size_t full;
assert(h);
assert(size);
if (size < sizeof(struct bus_header))
return false;
full = sizeof(struct bus_header) +
(h->endian == SD_BUS_NATIVE_ENDIAN ? h->fields_size : bswap_32(h->fields_size));
return size >= full;
}
int bus_header_message_size(struct bus_header *h, size_t *sum) {
size_t fs, bs;
assert(h);
src/libsystemd-bus/bus-message.h
+13 -4
View File
@@ -89,14 +89,12 @@ struct sd_bus_message {
bool uid_valid:1;
bool gid_valid:1;
bool free_header:1;
bool free_fields:1;
bool free_kdbus:1;
bool free_fds:1;
bool release_kdbus:1;
bool poisoned:1;
struct bus_header *header;
void *fields;
struct bus_body_part body;
struct bus_body_part *body_end;
unsigned n_body_parts;
@@ -114,7 +112,7 @@ struct sd_bus_message {
unsigned n_containers;
struct iovec *iovec;
struct iovec iovec_fixed[3];
struct iovec iovec_fixed[2];
unsigned n_iovec;
struct kdbus_msg *kdbus;
@@ -178,6 +176,16 @@ static inline uint32_t BUS_MESSAGE_SIZE(sd_bus_message *m) {
BUS_MESSAGE_BODY_SIZE(m);
}
static inline uint32_t BUS_MESSAGE_BODY_BEGIN(sd_bus_message *m) {
return
sizeof(struct bus_header) +
ALIGN8(BUS_MESSAGE_FIELDS_SIZE(m));
}
static inline void* BUS_MESSAGE_FIELDS(sd_bus_message *m) {
return (uint8_t*) m->header + sizeof(struct bus_header);
}
static inline void bus_message_unrefp(sd_bus_message **m) {
sd_bus_message_unref(*m);
}
@@ -214,7 +222,8 @@ int bus_message_append_ap(sd_bus_message *m, const char *types, va_list ap);
int bus_message_parse_fields(sd_bus_message *m);
int bus_header_size(struct bus_header *h, size_t *sum);
bool bus_header_is_complete(struct bus_header *h, size_t size);
int bus_header_message_size(struct bus_header *h, size_t *sum);
struct bus_body_part *message_append_part(sd_bus_message *m);
src/libsystemd-bus/bus-socket.c
+2 -8
View File
@@ -83,7 +83,7 @@ static int bus_message_setup_iovec(sd_bus_message *m) {
assert(!m->iovec);
n = 1 + !!m->fields + m->n_body_parts;
n = 1 + m->n_body_parts;
if (n < ELEMENTSOF(m->iovec_fixed))
m->iovec = m->iovec_fixed;
else {
@@ -92,16 +92,10 @@ static int bus_message_setup_iovec(sd_bus_message *m) {
return -ENOMEM;
}
r = append_iovec(m, m->header, sizeof(*m->header));
r = append_iovec(m, m->header, BUS_MESSAGE_BODY_BEGIN(m));
if (r < 0)
return r;
if (m->fields) {
r = append_iovec(m, m->fields, ALIGN8(m->header->fields_size));
if (r < 0)
return r;
}
MESSAGE_FOREACH_PART(part, i, m) {
r = append_iovec(m, part->data, part->size);
if (r < 0)