1 files changed, 93 insertions, 0 deletions
diff --git a/sysdeps/unix/sysv/linux/recvmsg.c b/sysdeps/unix/sysv/linux/recvmsg.c
new file mode 100644
index 0000000000..04cf230828
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/recvmsg.c
@@ -0,0 +1,93 @@
+/* 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 <string.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 __recvmsg (int, struct msghdr *, int);
+
+int
+recvmsg (fd, message, flags)
+     int fd;
+     struct msghdr *message;
+     int flags;
+{
+  struct cmsghdr *cm;
+  int ret;
+  int found_creds = 0;
+
+  /* Must check for space first. */
+  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;
+	    }
+	  found_creds = 1;
+	}
+      cm = CMSG_NXTHDR (message, cm);
+    }
+
+
+  ret = __recvmsg (fd, message, flags);
+
+  if (ret == -1)
+    return ret;
+
+  /* Postprocess the message control block for SCM_CREDS. */
+  cm = CMSG_FIRSTHDR (message);
+  if (found_creds)
+    while (cm)
+      {
+	if (cm->cmsg_type == SCM_CREDS)
+	  {
+	    struct cmsgcred *c = (struct cmsgcred *) CMSG_DATA (cm);
+	    struct __kernel_ucred u;
+	    int i;
+	    memcpy (&u, CMSG_DATA (cm), sizeof (struct __kernel_ucred));
+
+	    c->cmcred_pid = u.pid;
+	    c->cmcred_uid = u.uid;
+	    c->cmcred_gid = u.gid;
+
+	    c->cmcred_euid = -1;
+	    c->cmcred_ngroups = 0;
+	    for (i = 0; i < CMGROUP_MAX; i++)
+	      c->cmcred_groups[i] = -1;
+	  }
+	cm = CMSG_NXTHDR (message, cm);
+      }
+  return ret;
+}