linux_dsm_epyc7002/fs
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
..
9p 9p: re-enable mount time debug option 2007-07-14 15:14:14 -05:00
adfs sendfile: remove .sendfile from filesystems that use generic_file_sendfile() 2007-07-10 08:04:13 +02:00
affs sendfile: remove .sendfile from filesystems that use generic_file_sendfile() 2007-07-10 08:04:13 +02:00
afs AFS: drop explicit extern 2007-07-16 09:05:43 -07:00
autofs Replace pid_t in autofs with struct pid reference 2007-05-11 08:29:36 -07:00
autofs4 Fix some coding-style errors in autofs 2007-05-11 08:29:36 -07:00
befs Remove SLAB_CTOR_CONSTRUCTOR 2007-05-17 05:23:04 -07:00
bfs sendfile: remove .sendfile from filesystems that use generic_file_sendfile() 2007-07-10 08:04:13 +02:00
cifs sendfile: remove .sendfile from filesystems that use generic_file_sendfile() 2007-07-10 08:04:13 +02:00
coda wrong order of arguments of ->readdir() 2007-07-15 16:40:51 -07:00
configfs Detach sched.h from mm.h 2007-05-21 09:18:19 -07:00
cramfs mm: make read_cache_page synchronous 2007-05-07 12:12:51 -07:00
debugfs debugfs: add rename for debugfs files 2007-07-11 16:09:00 -07:00
devpts devpts: add fsnotify create event 2007-05-08 11:14:59 -07:00
dlm [DLM] dump more lock values 2007-07-09 08:24:13 +01:00
ecryptfs sysfs: kill unnecessary attribute->owner 2007-07-11 16:09:06 -07:00
efs Remove SLAB_CTOR_CONSTRUCTOR 2007-05-17 05:23:04 -07:00
exportfs header cleaning: don't include smp_lock.h when not used 2007-05-08 11:15:07 -07:00
ext2 ext2: fix a comment when ext2_release_file() is called 2007-07-16 09:05:44 -07:00
ext3 sendfile: remove .sendfile from filesystems that use generic_file_sendfile() 2007-07-10 08:04:13 +02:00
ext4 sendfile: remove .sendfile from filesystems that use generic_file_sendfile() 2007-07-10 08:04:13 +02:00
fat fat: gcc 4.3 warning fix 2007-07-16 09:05:42 -07:00
freevxfs vxfs warning fixes 2007-07-16 09:05:41 -07:00
fuse sendfile: remove .sendfile from filesystems that use generic_file_sendfile() 2007-07-10 08:04:13 +02:00
gfs2 Merge git://git.kernel.org/pub/scm/linux/kernel/git/steve/gfs2-2.6-nmw 2007-07-10 13:56:13 -07:00
hfs sendfile: remove .sendfile from filesystems that use generic_file_sendfile() 2007-07-10 08:04:13 +02:00
hfsplus sendfile: remove .sendfile from filesystems that use generic_file_sendfile() 2007-07-10 08:04:13 +02:00
hostfs sendfile: remove .sendfile from filesystems that use generic_file_sendfile() 2007-07-10 08:04:13 +02:00
hpfs sendfile: remove .sendfile from filesystems that use generic_file_sendfile() 2007-07-10 08:04:13 +02:00
hppfs [PATCH] Mark struct super_operations const 2007-02-12 09:48:47 -08:00
hugetlbfs shm: fix the filename of hugetlb sysv shared memory 2007-06-16 13:16:16 -07:00
isofs remove useless tolower in isofs 2007-07-16 09:05:43 -07:00
jbd jbd commit: fix transaction dropping 2007-07-16 09:05:34 -07:00
jbd2 jbd2 commit: fix transaction dropping 2007-07-16 09:05:34 -07:00
jffs2 sendfile: remove .sendfile from filesystems that use generic_file_sendfile() 2007-07-10 08:04:13 +02:00
jfs sendfile: remove .sendfile from filesystems that use generic_file_sendfile() 2007-07-10 08:04:13 +02:00
lockd NLM: fix source address of callback to client 2007-07-10 23:40:49 -04:00
minix sendfile: remove .sendfile from filesystems that use generic_file_sendfile() 2007-07-10 08:04:13 +02:00
msdos [PATCH] mark struct inode_operations const 2 2007-02-12 09:48:46 -08:00
ncpfs Only send SIGXFSZ when exceeding rlimits. 2007-07-16 09:05:43 -07:00
nfs Make NFS client use seq_list_xxx helpers 2007-07-16 09:05:42 -07:00
nfs_common [PATCH] nfs_common endianness annotations 2006-10-20 10:26:41 -07:00
nfsd Merge git://git.linux-nfs.org/pub/linux/nfs-2.6 2007-07-13 16:46:18 -07:00
nls [PATCH] fs: make nls_cp936.c handle some U00XY characters and U20AC correctly 2006-12-07 08:39:46 -08:00
ntfs sendfile: remove .sendfile from filesystems that use generic_file_sendfile() 2007-07-10 08:04:13 +02:00
ocfs2 sysfs: kill unnecessary attribute->owner 2007-07-11 16:09:06 -07:00
openpromfs Remove SLAB_CTOR_CONSTRUCTOR 2007-05-17 05:23:04 -07:00
partitions fix compiler warnings in acorn.c 2007-07-16 09:05:42 -07:00
proc /proc/*/environ: wrong placing of ptrace_may_attach() check 2007-07-16 09:05:44 -07:00
qnx4 sendfile: remove .sendfile from filesystems that use generic_file_sendfile() 2007-07-10 08:04:13 +02:00
ramfs sendfile: remove .sendfile from filesystems that use generic_file_sendfile() 2007-07-10 08:04:13 +02:00
reiserfs Only send SIGXFSZ when exceeding rlimits. 2007-07-16 09:05:43 -07:00
romfs Remove SLAB_CTOR_CONSTRUCTOR 2007-05-17 05:23:04 -07:00
smbfs sendfile: remove .sendfile from filesystems that use generic_file_sendfile() 2007-07-10 08:04:13 +02:00
sysfs sysfs: add parameter "struct bin_attribute *" in .read/.write methods for sysfs binary attributes 2007-07-11 16:09:09 -07:00
sysv sendfile: remove .sendfile from filesystems that use generic_file_sendfile() 2007-07-10 08:04:13 +02:00
udf UDF: check for allocated memory for inode data 2007-07-16 09:05:41 -07:00
ufs sendfile: remove .sendfile from filesystems that use generic_file_sendfile() 2007-07-10 08:04:13 +02:00
vfat [PATCH] mark struct inode_operations const 3 2007-02-12 09:48:46 -08:00
xfs [XFS] Fix lockdep annotations for xfs_lock_inodes 2007-07-14 18:09:42 +10:00
aio.c signal/timer/event: KAIO eventfd support example 2007-05-11 08:29:37 -07:00
anon_inodes.c signal/timer/event fds: anonymous inode source 2007-05-11 08:29:36 -07:00
attr.c header cleaning: don't include smp_lock.h when not used 2007-05-08 11:15:07 -07:00
bad_inode.c sendfile: remove bad_sendfile() from bad_file_ops 2007-07-10 08:04:15 +02:00
binfmt_aout.c [PATCH] VFS: change struct file to use struct path 2006-12-08 08:28:41 -08:00
binfmt_elf_fdpic.c header cleaning: don't include smp_lock.h when not used 2007-05-08 11:15:07 -07:00
binfmt_elf.c PIE randomization 2007-07-16 09:05:42 -07:00
binfmt_em86.c header cleaning: don't include smp_lock.h when not used 2007-05-08 11:15:07 -07:00
binfmt_flat.c nommu: report correct errno in message 2007-06-08 17:23:32 -07:00
binfmt_misc.c Detach sched.h from mm.h 2007-05-21 09:18:19 -07:00
binfmt_script.c header cleaning: don't include smp_lock.h when not used 2007-05-08 11:15:07 -07:00
binfmt_som.c [PARISC] Fix fs/binfmt_som.c 2006-10-04 06:51:26 -06:00
bio.c unexport bio_{,un}map_user 2007-07-10 08:03:34 +02:00
block_dev.c fs/block_dev.c: use list_for_each_entry() 2007-07-16 09:05:45 -07:00
buffer.c buffer: kill old incorrect comment 2007-07-16 09:05:45 -07:00
char_dev.c [PATCH] remove protection of LANANA-reserved majors 2007-04-04 21:12:47 -07:00
compat_ioctl.c fix compat console unimap regression 2007-05-25 17:37:46 -07:00
compat.c optimize compat_core_sys_select() by a using stack space for small fd sets 2007-05-23 20:14:12 -07:00
dcache.c header cleaning: don't include smp_lock.h when not used 2007-05-08 11:15:07 -07:00
dcookies.c [PATCH] slab: remove kmem_cache_t 2006-12-07 08:39:25 -08:00
direct-io.c dio: remove bogus refcounting BUG_ON 2007-07-03 18:23:23 -07:00
dnotify.c [PATCH] VFS: change struct file to use struct path 2006-12-08 08:28:41 -08:00
dquot.c circular locking dependency found in QUOTA OFF 2007-05-17 05:23:05 -07:00
drop_caches.c invalidate_mapping_pages(): add cond_resched 2007-07-16 09:05:36 -07:00
eventfd.c eventfd use waitqueue lock ... 2007-05-18 13:09:34 -07:00
eventpoll.c epoll: move kfree inside ep_free 2007-05-15 08:54:00 -07:00
exec.c uselib: add missing MNT_NOEXEC check 2007-05-23 20:14:13 -07:00
fcntl.c [PATCH] fdtable: Make fdarray and fdsets equal in size 2006-12-10 09:57:22 -08:00
fifo.c Detach sched.h from mm.h 2007-05-21 09:18:19 -07:00
file_table.c header cleaning: don't include smp_lock.h when not used 2007-05-08 11:15:07 -07:00
file.c [PATCH] fdtable: Provide free_fdtable() wrapper 2006-12-22 08:55:50 -08:00
filesystems.c add filesystem subtype support 2007-05-08 11:15:01 -07:00
fs-writeback.c Write back inode data pages even when the inode itself is locked 2007-01-26 12:53:20 -08:00
generic_acl.c [PATCH] Generic infrastructure for acls 2006-09-29 09:18:24 -07:00
inode.c Remove SLAB_CTOR_CONSTRUCTOR 2007-05-17 05:23:04 -07:00
inotify_user.c [PATCH] inotify: read return val fix 2007-02-12 09:48:28 -08:00
inotify.c Introduce a handy list_first_entry macro 2007-05-08 11:15:11 -07:00
internal.h cleanup compat ioctl handling 2007-05-08 11:15:09 -07:00
ioctl.c vanishing ioctl handler debugging 2007-06-04 13:25:10 -07:00
ioprio.c [PATCH] pid: replace do/while_each_task_pid with do/while_each_pid_task 2007-02-12 09:48:32 -08:00
Kconfig 9p: Reorganization of 9p file system code 2007-07-14 15:13:40 -05:00
Kconfig.binfmt fs: Kill sh dependency for binfmt_flat. 2007-05-21 14:34:00 +09:00
libfs.c fs/libfs.c: >80 columns line break fix 2007-05-09 06:44:57 +02:00
locks.c Remove SLAB_CTOR_CONSTRUCTOR 2007-05-17 05:23:04 -07:00
Makefile signal/timer/event: eventfd core 2007-05-11 08:29:36 -07:00
mbcache.c [PATCH] slab: remove kmem_cache_t 2006-12-07 08:39:25 -08:00
mpage.c consolidate generic_writepages and mpage_writepages 2007-05-11 08:29:35 -07:00
namei.c [PATCH] complete message queue auditing 2007-05-11 05:38:26 -04:00
namespace.c Make /proc/self/mounts(tats) use seq_list_xxx helpers 2007-07-16 09:05:42 -07:00
nfsctl.c
no-block.c [PATCH] BLOCK: Make it possible to disable the block layer [try #6] 2006-09-30 20:52:31 +02:00
open.c O_CLOEXEC for SCM_RIGHTS 2007-07-16 09:05:45 -07:00
pipe.c pipe: add documentation and comments 2007-07-10 08:04:16 +02:00
pnode.c Introduce a handy list_first_entry macro 2007-05-08 11:15:11 -07:00
pnode.h [PATCH] rename struct namespace to struct mnt_namespace 2006-12-08 08:28:51 -08:00
posix_acl.c [PATCH] kmemdup: some users 2006-10-01 00:39:19 -07:00
quota_v1.c
quota_v2.c
quota.c circular locking dependency found in QUOTA OFF 2007-05-17 05:23:05 -07:00
read_write.c Remove remnants of sendfile() 2007-07-10 08:04:15 +02:00
read_write.h [PATCH] Remove readv/writev methods and use aio_read/aio_write instead 2006-10-01 00:39:28 -07:00
readdir.c ROUND_UP macro cleanup in fs/(select|compat|readdir).c 2007-05-08 11:15:09 -07:00
select.c Style fix in fs/select.c 2007-05-09 07:10:02 +02:00
seq_file.c mutex_unlock() later in seq_lseek() 2007-07-16 09:05:44 -07:00
signalfd.c avoid spurious POLLIN returns in signalfd 2007-06-28 11:34:54 -07:00
splice.c splice: fix offset mangling with direct splicing (sendfile) 2007-07-13 14:14:31 +02:00
stack.c [PATCH] fs/stack.c: Copy i_nlink after all other attributes are copied 2007-02-19 14:21:50 -08:00
stat.c header cleaning: don't include smp_lock.h when not used 2007-05-08 11:15:07 -07:00
super.c add filesystem subtype support 2007-05-08 11:15:01 -07:00
sync.c Introduce fixed sys_sync_file_range2() syscall, implement on PowerPC and ARM 2007-06-28 11:38:30 -07:00
timerfd.c timerfd use waitqueue lock ... 2007-05-18 13:09:34 -07:00
utimes.c Fix permission checking for the new utimensat() system call 2007-07-08 12:02:55 -07:00
xattr_acl.c [PATCH] remove many unneeded #includes of sched.h 2007-02-14 08:09:54 -08:00
xattr.c [PATCH] audit inode for all xattr syscalls 2007-05-11 05:38:26 -04:00