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authorTom Gundersen <teg@jklm.no>2014-04-14 17:20:51 +0200
committerTom Gundersen <teg@jklm.no>2014-04-14 17:53:21 +0200
commita88f77c406ea56160c1e5a4b39eab1de134abe40 (patch)
treed1da4d5a0fae4a11dfa5429e65c03b09109a55a6
parent1403f45ab61d6f2026a3a7a06b52a536c1b7a3b3 (diff)
sd-rtnl: socket_read - use a read buffer
Rather than allocating/freeing memory for each message read, keep a global read buffer in the rtnl object. Also, rather than using a fixed size, peek at the pending message header to get the message size and reallocate as necessary.
-rw-r--r--src/libsystemd/sd-rtnl/rtnl-internal.h3
-rw-r--r--src/libsystemd/sd-rtnl/rtnl-message.c57
-rw-r--r--src/libsystemd/sd-rtnl/sd-rtnl.c8
3 files changed, 38 insertions, 30 deletions
diff --git a/src/libsystemd/sd-rtnl/rtnl-internal.h b/src/libsystemd/sd-rtnl/rtnl-internal.h
index 2f788d04f6..6dd65b2de7 100644
--- a/src/libsystemd/sd-rtnl/rtnl-internal.h
+++ b/src/libsystemd/sd-rtnl/rtnl-internal.h
@@ -72,6 +72,9 @@ struct sd_rtnl {
unsigned wqueue_size;
size_t wqueue_allocated;
+ struct nlmsghdr *rbuffer;
+ size_t rbuffer_allocated;
+
bool processing:1;
uint32_t serial;
diff --git a/src/libsystemd/sd-rtnl/rtnl-message.c b/src/libsystemd/sd-rtnl/rtnl-message.c
index 3a24cb885f..a93cb0c8e4 100644
--- a/src/libsystemd/sd-rtnl/rtnl-message.c
+++ b/src/libsystemd/sd-rtnl/rtnl-message.c
@@ -997,26 +997,6 @@ int sd_rtnl_message_get_errno(sd_rtnl_message *m) {
return err->error;
}
-static int message_receive_need(sd_rtnl *rtnl, size_t *need) {
- assert(rtnl);
- assert(need);
-
- /* ioctl(rtnl->fd, FIONREAD, &need)
- Does not appear to work on netlink sockets. libnl uses
- MSG_PEEK instead. I don't know if that is worth the
- extra roundtrip.
-
- For now we simply use the maximum message size the kernel
- may use (NLMSG_GOODSIZE), and then realloc to the actual
- size after reading the message (hence avoiding huge memory
- usage in case many small messages are kept around) */
- *need = page_size();
- if (*need > 8192UL)
- *need = 8192UL;
-
- return 0;
-}
-
int rtnl_message_parse(sd_rtnl_message *m,
size_t **rta_offset_tb,
unsigned short *rta_tb_size,
@@ -1082,7 +1062,6 @@ int socket_write_message(sd_rtnl *nl, sd_rtnl_message *m) {
int socket_read_message(sd_rtnl *rtnl) {
_cleanup_rtnl_message_unref_ sd_rtnl_message *first = NULL;
sd_rtnl_message *previous = NULL;
- _cleanup_free_ void *buffer = NULL;
uint8_t cred_buffer[CMSG_SPACE(sizeof(struct ucred))];
struct iovec iov = {};
struct msghdr msg = {
@@ -1094,23 +1073,37 @@ int socket_read_message(sd_rtnl *rtnl) {
struct cmsghdr *cmsg;
bool auth = false;
struct nlmsghdr *new_msg;
- size_t need, len;
+ size_t len;
int r, ret = 0;
assert(rtnl);
+ assert(rtnl->rbuffer);
- r = message_receive_need(rtnl, &need);
+ iov.iov_base = rtnl->rbuffer;
+ iov.iov_len = rtnl->rbuffer_allocated;
+
+ /* peek at the pending message header to get the message size */
+ r = recvmsg(rtnl->fd, &msg, MSG_PEEK);
if (r < 0)
- return r;
+ /* no data */
+ return (errno == EAGAIN) ? 0 : -errno;
+ else if (r == 0)
+ /* connection was closed by the kernel */
+ return -ECONNRESET;
+ else if ((size_t)r < sizeof(struct nlmsghdr))
+ return -EIO;
- buffer = malloc0(need);
- if (!buffer)
+ /* make room for the pending message */
+ if (!greedy_realloc((void **)&rtnl->rbuffer,
+ &rtnl->rbuffer_allocated,
+ rtnl->rbuffer->nlmsg_len,
+ sizeof(uint8_t)))
return -ENOMEM;
- iov.iov_base = buffer;
- iov.iov_len = need;
+ iov.iov_base = rtnl->rbuffer;
+ iov.iov_len = rtnl->rbuffer_allocated;
- r = recvmsg(rtnl->fd, &msg, 0);
+ r = recvmsg(rtnl->fd, &msg, MSG_TRUNC);
if (r < 0)
/* no data */
return (errno == EAGAIN) ? 0 : -errno;
@@ -1120,6 +1113,10 @@ int socket_read_message(sd_rtnl *rtnl) {
else
len = (size_t)r;
+ if (len > rtnl->rbuffer_allocated)
+ /* message did not fit in read buffer */
+ return -EIO;
+
for (cmsg = CMSG_FIRSTHDR(&msg); cmsg; cmsg = CMSG_NXTHDR(&msg, cmsg)) {
if (cmsg->cmsg_level == SOL_SOCKET &&
cmsg->cmsg_type == SCM_CREDENTIALS &&
@@ -1138,7 +1135,7 @@ int socket_read_message(sd_rtnl *rtnl) {
/* not from the kernel, ignore */
return 0;
- for (new_msg = buffer; NLMSG_OK(new_msg, len); new_msg = NLMSG_NEXT(new_msg, len)) {
+ for (new_msg = rtnl->rbuffer; NLMSG_OK(new_msg, len); new_msg = NLMSG_NEXT(new_msg, len)) {
_cleanup_rtnl_message_unref_ sd_rtnl_message *m = NULL;
const NLType *nl_type;
diff --git a/src/libsystemd/sd-rtnl/sd-rtnl.c b/src/libsystemd/sd-rtnl/sd-rtnl.c
index 367f165a1c..e4d436bb17 100644
--- a/src/libsystemd/sd-rtnl/sd-rtnl.c
+++ b/src/libsystemd/sd-rtnl/sd-rtnl.c
@@ -54,6 +54,12 @@ static int sd_rtnl_new(sd_rtnl **ret) {
if (!GREEDY_REALLOC(rtnl->wqueue, rtnl->wqueue_allocated, 1))
return -ENOMEM;
+ /* We guarantee that the read buffer has at least space for
+ * a message header */
+ if (!greedy_realloc((void**)&rtnl->rbuffer, &rtnl->rbuffer_allocated,
+ sizeof(struct nlmsghdr), sizeof(uint8_t)))
+ return -ENOMEM;
+
*ret = rtnl;
rtnl = NULL;
@@ -133,6 +139,8 @@ sd_rtnl *sd_rtnl_unref(sd_rtnl *rtnl) {
sd_rtnl_message_unref(rtnl->wqueue[i]);
free(rtnl->wqueue);
+ free(rtnl->rbuffer);
+
hashmap_free_free(rtnl->reply_callbacks);
prioq_free(rtnl->reply_callbacks_prioq);