@@@ more mess

[mLib] / sys / fdpass.c

diff --git a/sys/fdpass.c b/sys/fdpass.c
index e860ec360594731353560d4e1460827ef4010a0f..b890628029699442ef7f03b4c71d97034a9326cc 100644 (file)
--- a/sys/fdpass.c
+++ b/sys/fdpass.c
@@ -42,6 +42,7 @@
 #include <sys/un.h>
 
 #include "fdpass.h"
+#include "macros.h"
 
 /*----- Main code ---------------------------------------------------------*/
 
@@ -68,7 +69,7 @@ ssize_t fdpass_send(int sock, int fd, const void *p, size_t sz)
   struct cmsghdr *cmsg;
 #endif
 
-  iov.iov_base = (/*unconst*/ void *)p;
+  iov.iov_base = UNCONST(void, p);
   iov.iov_len = sz;
   msg.msg_name = 0;
   msg.msg_namelen = 0;
@@ -104,13 +105,19 @@ ssize_t fdpass_send(int sock, int fd, const void *p, size_t sz)
  *             otherwise it will.  At most one descriptor will be collected.
  */
 
+/* Qemu 2.8.1 clobbers 12 bytes beyond the end of the control-message
+ * buffer.  This is fixed in 2.12, but I'll bodge it for the sake of Debian
+ * stable.
+ */
+#define QEMU_SCRATCHSZ 16
+
 ssize_t fdpass_recv(int sock, int *fd, void *p, size_t sz)
 {
   struct iovec iov;
   struct msghdr msg;
   ssize_t rc;
 #ifndef HAVE_MSG_ACCRIGHTS
-  char buf[CMSG_SPACE(sizeof(fd))];
+  char buf[CMSG_SPACE(sizeof(fd)) + QEMU_SCRATCHSZ];
   struct cmsghdr *cmsg;
   int fdtmp;
 #endif
@@ -128,7 +135,7 @@ ssize_t fdpass_recv(int sock, int *fd, void *p, size_t sz)
 #else
   msg.msg_flags = 0;
   msg.msg_control = buf;
-  msg.msg_controllen = sizeof(buf);
+  msg.msg_controllen = sizeof(buf) - QEMU_SCRATCHSZ;
 #endif
   if ((rc = recvmsg(sock, &msg, 0)) < 0)
     return (rc);
@@ -139,7 +146,7 @@ ssize_t fdpass_recv(int sock, int *fd, void *p, size_t sz)
   for (cmsg = CMSG_FIRSTHDR(&msg); cmsg; cmsg = CMSG_NXTHDR(&msg, cmsg)) {
     if (cmsg->cmsg_level == SOL_SOCKET &&
        cmsg->cmsg_type == SCM_RIGHTS &&
-       cmsg->cmsg_len >= CMSG_LEN(sizeof(fd))) {
+       cmsg->cmsg_len >= CMSG_LEN(sizeof(*fd))) {
       memcpy(&fdtmp, CMSG_DATA(cmsg), sizeof(fdtmp));
       if (*fd == -1)
        *fd = fdtmp;
@@ -151,4 +158,6 @@ ssize_t fdpass_recv(int sock, int *fd, void *p, size_t sz)
   return (rc);
 }
 
+#undef QEMU_SCRATCHSZ
+
 /*----- That's all, folks -------------------------------------------------*/