1 files changed, 51 insertions, 21 deletions
diff --git a/sysdeps/unix/sysv/linux/sendmmsg.c b/sysdeps/unix/sysv/linux/sendmmsg.c
index 6e0d46be9e..9b193438ce 100644
--- a/sysdeps/unix/sysv/linux/sendmmsg.c
+++ b/sysdeps/unix/sysv/linux/sendmmsg.c
@@ -16,12 +16,10 @@
    License along with the GNU C Library; if not, see
    <http://www.gnu.org/licenses/>.  */
 
-#include <errno.h>
 #include <sys/socket.h>
-
+#include <socketcall.h>
 #include <sysdep-cancel.h>
-#include <sys/syscall.h>
-#include <kernel-features.h>
+#include <shlib-compat.h>
 
 /* Do not use the sendmmsg syscall on socketcall architectures unless
    it was added at the same time as the socketcall support or can be
@@ -32,31 +30,53 @@
 # undef __NR_sendmmsg
 #endif
 
-#ifdef __NR_sendmmsg
+#if __WORDSIZE == 64
+static inline int
+send_mmsghdr (int fd, struct mmsghdr *vmessages, unsigned int vlen, int flags)
+{
+  /* Emulate kernel interface for vlen size.  */
+  if (vlen > IOV_MAX)
+    vlen = IOV_MAX;
+  if (vlen == 0)
+    return 0;
+  /* POSIX specifies that both msghdr::msg_iovlen and msghdr::msg_controllen
+     to be int and socklen_t respectively,  however Linux defines it as both
+     size_t.  So for 64-bit it requires some adjustments by copying to
+     temporary header and zeroing the pad fields.
+     The problem is sendmmsg's msghdr may points to an already-filled control
+     buffer and modifying it is not part of sendmmsg contract (the data may
+     be in ro map).  So interact over the msghdr calling the sendmsg that
+     adjust the header using a temporary buffer.  */
+  for (unsigned int i = 0; i < vlen; i++)
+    {
+      ssize_t ret = __sendmsg (fd, &vmessages[i].msg_hdr, flags);
+      if (ret < 0)
+	return -1;
+      vmessages[i].msg_len = ret;
+    }
+  return 1;
+}
+#endif
+
 int
 __sendmmsg (int fd, struct mmsghdr *vmessages, unsigned int vlen, int flags)
 {
+#if __WORDSIZE == 64
+  return send_mmsghdr (fd, vmessages, vlen, flags);
+#elif defined __NR_sendmmsg
   return SYSCALL_CANCEL (sendmmsg, fd, vmessages, vlen, flags);
-}
-libc_hidden_def (__sendmmsg)
-weak_alias (__sendmmsg, sendmmsg)
 #elif defined __NR_socketcall
-# include <socketcall.h>
 # ifdef __ASSUME_SENDMMSG_SOCKETCALL
-int
-__sendmmsg (int fd, struct mmsghdr *vmessages, unsigned int vlen, int flags)
-{
   return SOCKETCALL_CANCEL (sendmmsg, fd, vmessages, vlen, flags);
-}
 # else
-static int have_sendmmsg;
-
-int
-__sendmmsg (int fd, struct mmsghdr *vmessages, unsigned int vlen, int flags)
-{
+  static int have_sendmmsg;
   if (__glibc_likely (have_sendmmsg >= 0))
     {
+#  if __WORDSIZE == 64
+      int ret = send_mmsghdr (fd, vmessages, vlen, flags);
+#  else
       int ret = SOCKETCALL_CANCEL (sendmmsg, fd, vmessages, vlen, flags);
+#  endif
       /* The kernel returns -EINVAL for unknown socket operations.
 	 We need to convert that error to an ENOSYS error.  */
       if (__builtin_expect (ret < 0, 0)
@@ -84,10 +104,20 @@ __sendmmsg (int fd, struct mmsghdr *vmessages, unsigned int vlen, int flags)
     }
   __set_errno (ENOSYS);
   return -1;
-}
 # endif /* __ASSUME_SENDMMSG_SOCKETCALL  */
+#else /* defined __NR_socketcall  */
+# define STUB 1
+  __set_errno (ENOSYS);
+  return -1;
+#endif
+}
+#ifdef STUB
+stub_warning (sendmmsg)
+#endif
+
 libc_hidden_def (__sendmmsg)
-weak_alias (__sendmmsg, sendmmsg)
+#if __WORDSIZE == 64
+versioned_symbol (libc, __sendmmsg, sendmmsg, GLIBC_2_24);
 #else
-# include <socket/sendmmsg.c>
+weak_alias (__sendmmsg, sendmmsg)
 #endif