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Flush the connection if we have to many marshaled fds

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The buffer used by wl_connection_data to receive a cmsg is 128 bytes
long. This can hold at most 28 fds but when a cmsg is generated for
sending the fds, there is no check for this limitation. The man page
for recvmsg does not show any way of recovering from MSG_CTRUNC, that
happens when the buffer supplied for cmsg is too short.

Fix this by flushing the data to be written instead of generating a
cmsg buffer longer than the maximum.
This commit is contained in:
Ander Conselvan de Oliveira 2012-03-09 12:51:42 +02:00 • committed by Kristian Høgsberg
parent 46df9232fa
commit 73d4a53672
1 changed files with 26 additions and 4 deletions
Download patch file Download diff file Expand all files Collapse all files

30
src/connection.c
View file

@ -56,9 +56,13 @@ struct wl_closure {
uint32_t *start;
};
#define MAX_FDS_OUT 28
#define CLEN (CMSG_LEN(MAX_FDS_OUT * sizeof(int32_t)))
struct wl_connection {
struct wl_buffer in, out;
struct wl_buffer fds_in, fds_out;
int n_fds_out;
int fd;
void *data;
wl_connection_update_func_t update;
@ -217,7 +221,7 @@ build_cmsg(struct wl_buffer *buffer, char *data, int *clen)
static void
close_fds(struct wl_buffer *buffer)
{
int fds[32], i, count;
int fds[MAX_FDS_OUT], i, count;
size_t size;
size = buffer->head - buffer->tail;
@ -252,7 +256,7 @@ wl_connection_data(struct wl_connection *connection, uint32_t mask)
{
struct iovec iov[2];
struct msghdr msg;
char cmsg[128];
char cmsg[CLEN];
int len, count, clen;
if (mask & WL_CONNECTION_WRITABLE) {
@ -389,6 +393,21 @@ wl_message_size_extra(const struct wl_message *message)
return extra;
}
static int
wl_connection_put_fd(struct wl_connection *connection, int32_t fd)
{
if (connection->n_fds_out + 1 > MAX_FDS_OUT) {
if (wl_connection_data(connection, WL_CONNECTION_WRITABLE))
return -1;
connection->n_fds_out = 0;
}
wl_buffer_put(&connection->fds_out, &fd, sizeof fd);
connection->n_fds_out++;
return 0;
}
struct wl_closure *
wl_connection_vmarshal(struct wl_connection *connection,
struct wl_object *sender,
@ -510,8 +529,11 @@ wl_connection_vmarshal(struct wl_connection *connection,
abort();
}
*fd_ptr = dup_fd;
wl_buffer_put(&connection->fds_out,
&dup_fd, sizeof dup_fd);
if (wl_connection_put_fd(connection, dup_fd)) {
printf("request could not be mashaled: "
"can't send file descriptor");
return NULL;
}
break;
default:
fprintf(stderr, "unhandled format code: '%c'\n",