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/* 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);
}
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