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kernel-ark/include/linux/socket.h
Ulrich Drepper 4a19542e5f O_CLOEXEC for SCM_RIGHTS 
Part two in the O_CLOEXEC saga: adding support for file descriptors received
through Unix domain sockets.

The patch is once again pretty minimal, it introduces a new flag for recvmsg
and passes it just like the existing MSG_CMSG_COMPAT flag.  I think this bit
is not used otherwise but the networking people will know better.

This new flag is not recognized by recvfrom and recv.  These functions cannot
be used for that purpose and the asymmetry this introduces is not worse than
the already existing MSG_CMSG_COMPAT situations.

The patch must be applied on the patch which introduced O_CLOEXEC.  It has to
remove static from the new get_unused_fd_flags function but since scm.c cannot
live in a module the function still hasn't to be exported.

Here's a test program to make sure the code works.  It's so much longer than
the actual patch...

#include <errno.h>
#include <error.h>
#include <fcntl.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <sys/socket.h>
#include <sys/un.h>

#ifndef O_CLOEXEC
# define O_CLOEXEC 02000000
#endif
#ifndef MSG_CMSG_CLOEXEC
# define MSG_CMSG_CLOEXEC 0x40000000
#endif

int
main (int argc, char *argv[])
{
  if (argc > 1)
    {
      int fd = atol (argv[1]);
      printf ("child: fd = %d\n", fd);
      if (fcntl (fd, F_GETFD) == 0 || errno != EBADF)
        {
          puts ("file descriptor valid in child");
          return 1;
        }
      return 0;

    }

  struct sockaddr_un sun;
  strcpy (sun.sun_path, "./testsocket");
  sun.sun_family = AF_UNIX;

  char databuf[] = "hello";
  struct iovec iov[1];
  iov[0].iov_base = databuf;
  iov[0].iov_len = sizeof (databuf);

  union
  {
    struct cmsghdr hdr;
    char bytes[CMSG_SPACE (sizeof (int))];
  } buf;
  struct msghdr msg = { .msg_iov = iov, .msg_iovlen = 1,
                        .msg_control = buf.bytes,
                        .msg_controllen = sizeof (buf) };
  struct cmsghdr *cmsg = CMSG_FIRSTHDR (&msg);

  cmsg->cmsg_level = SOL_SOCKET;
  cmsg->cmsg_type = SCM_RIGHTS;
  cmsg->cmsg_len = CMSG_LEN (sizeof (int));

  msg.msg_controllen = cmsg->cmsg_len;

  pid_t child = fork ();
  if (child == -1)
    error (1, errno, "fork");
  if (child == 0)
    {
      int sock = socket (PF_UNIX, SOCK_STREAM, 0);
      if (sock < 0)
        error (1, errno, "socket");

      if (bind (sock, (struct sockaddr *) &sun, sizeof (sun)) < 0)
        error (1, errno, "bind");
      if (listen (sock, SOMAXCONN) < 0)
        error (1, errno, "listen");

      int conn = accept (sock, NULL, NULL);
      if (conn == -1)
        error (1, errno, "accept");

      *(int *) CMSG_DATA (cmsg) = sock;
      if (sendmsg (conn, &msg, MSG_NOSIGNAL) < 0)
        error (1, errno, "sendmsg");

      return 0;
    }

  /* For a test suite this should be more robust like a
     barrier in shared memory.  */
  sleep (1);

  int sock = socket (PF_UNIX, SOCK_STREAM, 0);
  if (sock < 0)
    error (1, errno, "socket");

  if (connect (sock, (struct sockaddr *) &sun, sizeof (sun)) < 0)
    error (1, errno, "connect");
  unlink (sun.sun_path);

  *(int *) CMSG_DATA (cmsg) = -1;

  if (recvmsg (sock, &msg, MSG_CMSG_CLOEXEC) < 0)
    error (1, errno, "recvmsg");

  int fd = *(int *) CMSG_DATA (cmsg);
  if (fd == -1)
    error (1, 0, "no descriptor received");

  char fdname[20];
  snprintf (fdname, sizeof (fdname), "%d", fd);
  execl ("/proc/self/exe", argv[0], fdname, NULL);
  puts ("execl failed");
  return 1;
}

[akpm@linux-foundation.org: Fix fastcall inconsistency noted by Michael Buesch]
[akpm@linux-foundation.org: build fix]
Signed-off-by: Ulrich Drepper <drepper@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Michael Buesch <mb@bu3sch.de>
Cc: Michael Kerrisk <mtk-manpages@gmx.net>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-16 09:05:45 -07:00

316 lines
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#ifndef _LINUX_SOCKET_H
#define _LINUX_SOCKET_H
/*
* Desired design of maximum size and alignment (see RFC2553)
*/
#define _K_SS_MAXSIZE 128 /* Implementation specific max size */
#define _K_SS_ALIGNSIZE (__alignof__ (struct sockaddr *))
/* Implementation specific desired alignment */
struct __kernel_sockaddr_storage {
unsigned short ss_family; /* address family */
/* Following field(s) are implementation specific */
char __data[_K_SS_MAXSIZE - sizeof(unsigned short)];
/* space to achieve desired size, */
/* _SS_MAXSIZE value minus size of ss_family */
} __attribute__ ((aligned(_K_SS_ALIGNSIZE))); /* force desired alignment */
#if defined(__KERNEL__) || !defined(__GLIBC__) || (__GLIBC__ < 2)
#include <asm/socket.h> /* arch-dependent defines */
#include <linux/sockios.h> /* the SIOCxxx I/O controls */
#include <linux/uio.h> /* iovec support */
#include <linux/types.h> /* pid_t */
#include <linux/compiler.h> /* __user */
extern int sysctl_somaxconn;
#ifdef CONFIG_PROC_FS
struct seq_file;
extern void socket_seq_show(struct seq_file *seq);
#endif
typedef unsigned short sa_family_t;
/*
* 1003.1g requires sa_family_t and that sa_data is char.
*/
struct sockaddr {
sa_family_t sa_family; /* address family, AF_xxx */
char sa_data[14]; /* 14 bytes of protocol address */
};
struct linger {
int l_onoff; /* Linger active */
int l_linger; /* How long to linger for */
};
#define sockaddr_storage __kernel_sockaddr_storage
/*
* As we do 4.4BSD message passing we use a 4.4BSD message passing
* system, not 4.3. Thus msg_accrights(len) are now missing. They
* belong in an obscure libc emulation or the bin.
*/
struct msghdr {
void * msg_name; /* Socket name */
int msg_namelen; /* Length of name */
struct iovec * msg_iov; /* Data blocks */
__kernel_size_t msg_iovlen; /* Number of blocks */
void * msg_control; /* Per protocol magic (eg BSD file descriptor passing) */
__kernel_size_t msg_controllen; /* Length of cmsg list */
unsigned msg_flags;
};
/*
* POSIX 1003.1g - ancillary data object information
* Ancillary data consits of a sequence of pairs of
* (cmsghdr, cmsg_data[])
*/
struct cmsghdr {
__kernel_size_t cmsg_len; /* data byte count, including hdr */
int cmsg_level; /* originating protocol */
int cmsg_type; /* protocol-specific type */
};
/*
* Ancilliary data object information MACROS
* Table 5-14 of POSIX 1003.1g
*/
#define __CMSG_NXTHDR(ctl, len, cmsg) __cmsg_nxthdr((ctl),(len),(cmsg))
#define CMSG_NXTHDR(mhdr, cmsg) cmsg_nxthdr((mhdr), (cmsg))
#define CMSG_ALIGN(len) ( ((len)+sizeof(long)-1) & ~(sizeof(long)-1) )
#define CMSG_DATA(cmsg) ((void *)((char *)(cmsg) + CMSG_ALIGN(sizeof(struct cmsghdr))))
#define CMSG_SPACE(len) (CMSG_ALIGN(sizeof(struct cmsghdr)) + CMSG_ALIGN(len))
#define CMSG_LEN(len) (CMSG_ALIGN(sizeof(struct cmsghdr)) + (len))
#define __CMSG_FIRSTHDR(ctl,len) ((len) >= sizeof(struct cmsghdr) ? \
(struct cmsghdr *)(ctl) : \
(struct cmsghdr *)NULL)
#define CMSG_FIRSTHDR(msg) __CMSG_FIRSTHDR((msg)->msg_control, (msg)->msg_controllen)
#define CMSG_OK(mhdr, cmsg) ((cmsg)->cmsg_len >= sizeof(struct cmsghdr) && \
(cmsg)->cmsg_len <= (unsigned long) \
((mhdr)->msg_controllen - \
((char *)(cmsg) - (char *)(mhdr)->msg_control)))
/*
* This mess will go away with glibc
*/
#ifdef __KERNEL__
#define __KINLINE static inline
#elif defined(__GNUC__)
#define __KINLINE static __inline__
#elif defined(__cplusplus)
#define __KINLINE static inline
#else
#define __KINLINE static
#endif
/*
* Get the next cmsg header
*
* PLEASE, do not touch this function. If you think, that it is
* incorrect, grep kernel sources and think about consequences
* before trying to improve it.
*
* Now it always returns valid, not truncated ancillary object
* HEADER. But caller still MUST check, that cmsg->cmsg_len is
* inside range, given by msg->msg_controllen before using
* ancillary object DATA. --ANK (980731)
*/
__KINLINE struct cmsghdr * __cmsg_nxthdr(void *__ctl, __kernel_size_t __size,
struct cmsghdr *__cmsg)
{
struct cmsghdr * __ptr;
__ptr = (struct cmsghdr*)(((unsigned char *) __cmsg) + CMSG_ALIGN(__cmsg->cmsg_len));
if ((unsigned long)((char*)(__ptr+1) - (char *) __ctl) > __size)
return (struct cmsghdr *)0;
return __ptr;
}
__KINLINE struct cmsghdr * cmsg_nxthdr (struct msghdr *__msg, struct cmsghdr *__cmsg)
{
return __cmsg_nxthdr(__msg->msg_control, __msg->msg_controllen, __cmsg);
}
/* "Socket"-level control message types: */
#define SCM_RIGHTS 0x01 /* rw: access rights (array of int) */
#define SCM_CREDENTIALS 0x02 /* rw: struct ucred */
#define SCM_SECURITY 0x03 /* rw: security label */
struct ucred {
__u32 pid;
__u32 uid;
__u32 gid;
};
/* Supported address families. */
#define AF_UNSPEC 0
#define AF_UNIX 1 /* Unix domain sockets */
#define AF_LOCAL 1 /* POSIX name for AF_UNIX */
#define AF_INET 2 /* Internet IP Protocol */
#define AF_AX25 3 /* Amateur Radio AX.25 */
#define AF_IPX 4 /* Novell IPX */
#define AF_APPLETALK 5 /* AppleTalk DDP */
#define AF_NETROM 6 /* Amateur Radio NET/ROM */
#define AF_BRIDGE 7 /* Multiprotocol bridge */
#define AF_ATMPVC 8 /* ATM PVCs */
#define AF_X25 9 /* Reserved for X.25 project */
#define AF_INET6 10 /* IP version 6 */
#define AF_ROSE 11 /* Amateur Radio X.25 PLP */
#define AF_DECnet 12 /* Reserved for DECnet project */
#define AF_NETBEUI 13 /* Reserved for 802.2LLC project*/
#define AF_SECURITY 14 /* Security callback pseudo AF */
#define AF_KEY 15 /* PF_KEY key management API */
#define AF_NETLINK 16
#define AF_ROUTE AF_NETLINK /* Alias to emulate 4.4BSD */
#define AF_PACKET 17 /* Packet family */
#define AF_ASH 18 /* Ash */
#define AF_ECONET 19 /* Acorn Econet */
#define AF_ATMSVC 20 /* ATM SVCs */
#define AF_SNA 22 /* Linux SNA Project (nutters!) */
#define AF_IRDA 23 /* IRDA sockets */
#define AF_PPPOX 24 /* PPPoX sockets */
#define AF_WANPIPE 25 /* Wanpipe API Sockets */
#define AF_LLC 26 /* Linux LLC */
#define AF_TIPC 30 /* TIPC sockets */
#define AF_BLUETOOTH 31 /* Bluetooth sockets */
#define AF_IUCV 32 /* IUCV sockets */
#define AF_RXRPC 33 /* RxRPC sockets */
#define AF_MAX 34 /* For now.. */
/* Protocol families, same as address families. */
#define PF_UNSPEC AF_UNSPEC
#define PF_UNIX AF_UNIX
#define PF_LOCAL AF_LOCAL
#define PF_INET AF_INET
#define PF_AX25 AF_AX25
#define PF_IPX AF_IPX
#define PF_APPLETALK AF_APPLETALK
#define PF_NETROM AF_NETROM
#define PF_BRIDGE AF_BRIDGE
#define PF_ATMPVC AF_ATMPVC
#define PF_X25 AF_X25
#define PF_INET6 AF_INET6
#define PF_ROSE AF_ROSE
#define PF_DECnet AF_DECnet
#define PF_NETBEUI AF_NETBEUI
#define PF_SECURITY AF_SECURITY
#define PF_KEY AF_KEY
#define PF_NETLINK AF_NETLINK
#define PF_ROUTE AF_ROUTE
#define PF_PACKET AF_PACKET
#define PF_ASH AF_ASH
#define PF_ECONET AF_ECONET
#define PF_ATMSVC AF_ATMSVC
#define PF_SNA AF_SNA
#define PF_IRDA AF_IRDA
#define PF_PPPOX AF_PPPOX
#define PF_WANPIPE AF_WANPIPE
#define PF_LLC AF_LLC
#define PF_TIPC AF_TIPC
#define PF_BLUETOOTH AF_BLUETOOTH
#define PF_IUCV AF_IUCV
#define PF_RXRPC AF_RXRPC
#define PF_MAX AF_MAX
/* Maximum queue length specifiable by listen. */
#define SOMAXCONN 128
/* Flags we can use with send/ and recv.
Added those for 1003.1g not all are supported yet
*/
#define MSG_OOB 1
#define MSG_PEEK 2
#define MSG_DONTROUTE 4
#define MSG_TRYHARD 4 /* Synonym for MSG_DONTROUTE for DECnet */
#define MSG_CTRUNC 8
#define MSG_PROBE 0x10 /* Do not send. Only probe path f.e. for MTU */
#define MSG_TRUNC 0x20
#define MSG_DONTWAIT 0x40 /* Nonblocking io */
#define MSG_EOR 0x80 /* End of record */
#define MSG_WAITALL 0x100 /* Wait for a full request */
#define MSG_FIN 0x200
#define MSG_SYN 0x400
#define MSG_CONFIRM 0x800 /* Confirm path validity */
#define MSG_RST 0x1000
#define MSG_ERRQUEUE 0x2000 /* Fetch message from error queue */
#define MSG_NOSIGNAL 0x4000 /* Do not generate SIGPIPE */
#define MSG_MORE 0x8000 /* Sender will send more */
#define MSG_EOF MSG_FIN
#define MSG_CMSG_CLOEXEC 0x40000000 /* Set close_on_exit for file
descriptor received through
SCM_RIGHTS */
#if defined(CONFIG_COMPAT)
#define MSG_CMSG_COMPAT 0x80000000 /* This message needs 32 bit fixups */
#else
#define MSG_CMSG_COMPAT 0 /* We never have 32 bit fixups */
#endif
/* Setsockoptions(2) level. Thanks to BSD these must match IPPROTO_xxx */
#define SOL_IP 0
/* #define SOL_ICMP 1 No-no-no! Due to Linux :-) we cannot use SOL_ICMP=1 */
#define SOL_TCP 6
#define SOL_UDP 17
#define SOL_IPV6 41
#define SOL_ICMPV6 58
#define SOL_SCTP 132
#define SOL_UDPLITE 136 /* UDP-Lite (RFC 3828) */
#define SOL_RAW 255
#define SOL_IPX 256
#define SOL_AX25 257
#define SOL_ATALK 258
#define SOL_NETROM 259
#define SOL_ROSE 260
#define SOL_DECNET 261
#define SOL_X25 262
#define SOL_PACKET 263
#define SOL_ATM 264 /* ATM layer (cell level) */
#define SOL_AAL 265 /* ATM Adaption Layer (packet level) */
#define SOL_IRDA 266
#define SOL_NETBEUI 267
#define SOL_LLC 268
#define SOL_DCCP 269
#define SOL_NETLINK 270
#define SOL_TIPC 271
#define SOL_RXRPC 272
#define SOL_PPPOL2TP 273
/* IPX options */
#define IPX_TYPE 1
#ifdef __KERNEL__
extern int memcpy_fromiovec(unsigned char *kdata, struct iovec *iov, int len);
extern int memcpy_fromiovecend(unsigned char *kdata, struct iovec *iov,
int offset, int len);
extern int csum_partial_copy_fromiovecend(unsigned char *kdata,
struct iovec *iov,
int offset,
unsigned int len, __wsum *csump);
extern int verify_iovec(struct msghdr *m, struct iovec *iov, char *address, int mode);
extern int memcpy_toiovec(struct iovec *v, unsigned char *kdata, int len);
extern int move_addr_to_user(void *kaddr, int klen, void __user *uaddr, int __user *ulen);
extern int move_addr_to_kernel(void __user *uaddr, int ulen, void *kaddr);
extern int put_cmsg(struct msghdr*, int level, int type, int len, void *data);
#endif
#endif /* not kernel and not glibc */
#endif /* _LINUX_SOCKET_H */
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