commit c409572678936d3ffa8694f5a1dae531c2212e21
author Michael S. Tsirkin <mst@redhat.com> Sun Nov 02 18:48:32 2014 +0200
committer Michael S. Tsirkin <mst@redhat.com> Sun Nov 23 12:11:29 2014 +0200
tree 234bada2ba0f994940b6b96421d9e653fe925b9c
parent 0e88f478508b566152c6681f4889ed9830a2c0a5

qemu-char: fix tcp_get_fds

tcp_get_fds API discards fds if there's more than 1 of these.

It's tricky to fix this without API changes in the generic case.

However, this API is only used by tests ATM, and tests know how
many fds they expect.

So let's not waste cycles trying to fix this properly:
simply assume at most 16 fds (tests use at most 8 now).
assert if some test tries to get more.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

qemu-char.c

diff --git a/qemu-char.c b/qemu-char.c
index 4a76f0f..a8b01da 100644
--- a/qemu-char.c
+++ b/qemu-char.c
@@ -88,6 +88,7 @@
 #define READ_BUF_LEN 4096
 #define READ_RETRIES 10
 #define CHR_MAX_FILENAME_SIZE 256
+#define TCP_MAX_FDS 16
 
 /***********************************************************/
 /* Socket address helpers */
@@ -2668,6 +2669,8 @@
     TCPCharDriver *s = chr->opaque;
     int to_copy = (s->read_msgfds_num < num) ? s->read_msgfds_num : num;
 
+    assert(num <= TCP_MAX_FDS);
+
     if (to_copy) {
         int i;
 
@@ -2762,7 +2765,7 @@
     struct iovec iov[1];
     union {
         struct cmsghdr cmsg;
-        char control[CMSG_SPACE(sizeof(int))];
+        char control[CMSG_SPACE(sizeof(int) * TCP_MAX_FDS)];
     } msg_control;
     int flags = 0;
     ssize_t ret;