1 files changed, 91 insertions, 0 deletions
diff --git a/sysdeps/unix/sysv/linux/sendmsg.c b/sysdeps/unix/sysv/linux/sendmsg.c
new file mode 100644
index 0000000000..8902530c2b
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/sendmsg.c
@@ -0,0 +1,91 @@
+/* Copyright (C) 1998 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Library General Public License as
+   published by the Free Software Foundation; either version 2 of the
+   License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Library General Public License for more details.
+
+   You should have received a copy of the GNU Library General Public
+   License along with the GNU C Library; see the file COPYING.LIB.  If not,
+   write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+   Boston, MA 02111-1307, USA.  */
+
+#include <sys/socket.h>
+#include <errno.h>
+#include <unistd.h>
+
+#include <asm/posix_types.h>
+
+/* The kernel expects this structure in SCM_CREDS messages.
+ * Note: sizeof(struct __kernel_ucred) <= sizeof(struct cmsgcred) must hold.
+ */
+struct __kernel_ucred
+{
+  __kernel_pid_t pid;
+  __kernel_uid_t uid;
+  __kernel_gid_t gid;
+};
+
+extern int __sendmsg (int, const struct msghdr *, int);
+
+/* Send a message described by MESSAGE on socket FD.
+   Returns the number of bytes sent, or -1 for errors.  */
+int
+sendmsg (fd, message, flags)
+     int fd;
+     const struct msghdr *message;
+     int flags;
+{
+  struct cmsghdr *cm;
+  struct cmsgcred *cc;
+  struct __kernel_ucred *u;
+  pid_t pid;
+
+  /* Preprocess the message control block for SCM_CREDS. */
+  cm = CMSG_FIRSTHDR (message);
+  while (cm)
+    {
+      if (cm->cmsg_type == SCM_CREDS)
+	{
+	  if (cm->cmsg_len < CMSG_SPACE (sizeof (struct cmsgcred)))
+	    {
+	      __set_errno (EINVAL);
+	      return -1;
+	    }
+
+	  u = (struct __kernel_ucred *) CMSG_DATA (cm);
+	  cc = (struct cmsgcred *) CMSG_DATA (cm);
+	  /* Linux expects the calling process to pass in
+	     its credentials, and sanity checks them.
+	     You can send real, effective, or set- uid and gid.
+	     If the user hasn't filled in the buffer, we default to
+	     real uid and gid. */
+	  pid = getpid ();
+	  if (cc->cmcred_pid != pid)
+	  {
+	      u->pid = pid;
+	      u->uid = getuid ();
+	      u->gid = getgid ();
+	  }
+	  else
+	  {
+	      struct __kernel_ucred v;
+	      v.pid = cc->cmcred_pid;
+	      v.uid = cc->cmcred_uid;
+	      v.gid = cc->cmcred_gid;
+	      u->pid = v.pid;
+	      u->uid = v.uid;
+	      u->gid = v.gid;
+	  }
+	}
+      cm = CMSG_NXTHDR ((struct msghdr *) message, cm);
+    }
+
+  return __sendmsg (fd, message, flags);
+}