Cygwin: fhandler_socket_unix: implement socket, bind, and close

...plus lots of helper functions.  Add comment to explain how everything
works.  This comment will be improved while implementing the yet missing
parts.

Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
This commit is contained in:
Corinna Vinschen 2018-03-02 18:14:11 +01:00
parent 7d260cfac4
commit 97b7aaaeb7
2 changed files with 495 additions and 90 deletions

View File

@ -847,6 +847,24 @@ class sun_name_t
class fhandler_socket_unix : public fhandler_socket
{
protected:
HANDLE file; /* Either NT symlink or reparse point */
HANDLE create_abstract_link (const sun_name_t *sun,
PUNICODE_STRING pipe_name);
HANDLE create_reparse_point (const sun_name_t *sun,
PUNICODE_STRING pipe_name);
HANDLE create_file (const sun_name_t *sun);
int open_abstract_link (sun_name_t *sun, PUNICODE_STRING pipe_name);
int open_reparse_point (sun_name_t *sun, PUNICODE_STRING pipe_name);
int open_file (sun_name_t *sun, int &type, PUNICODE_STRING pipe_name);
HANDLE autobind (sun_name_t *sun);
wchar_t get_type_char ();
void gen_pipe_name ();
void set_wait_state (DWORD wait_state);
HANDLE create_pipe ();
HANDLE create_pipe_instance ();
protected:
sun_name_t *sun_path;
sun_name_t *peer_sun_path;

View File

@ -21,19 +21,47 @@
#include "path.h"
#include "fhandler.h"
#include "dtable.h"
#include "cygheap.h"
#include "hires.h"
#include "shared_info.h"
#include "ntdll.h"
#include "miscfuncs.h"
#include "tls_pbuf.h"
/*
Abstract socket:
An abstract socket is represented by a symlink in the native
NT namespace, within the Cygin subdir in BasedNamedObjects.
So it's globally available but only exists as long as at least on
descriptor on the socket is open, as desired.
The name of the symlink is: "af-unix-<sun_path>"
<sun_path> is the transposed sun_path string, including the leading
NUL. The transposition is simplified in that it uses every byte
in the valid sun_path name as is, no extra multibyte conversion.
The content of the symlink is the name of the underlying pipe.
Named socket:
A named socket is represented by a reparse point with a Cygwin-specific
tag and GUID. The GenericReparseBuffer content is the name of the
underlying pipe.
Pipe:
The pipe is named \\.\pipe\cygwin-<installation_key>-unix-[sd]-<uniq_id>
- <installation_key> is the 8 byte hex Cygwin installation key
- [sd] is s for SOCK_STREAM, d for SOCK_DGRAM
- <uniq_id> is an 8 byte hex unique number
Note: We use MAX_PATH here for convenience where sufficient. It's
big enough to hold sun_path's as well as pipe names so we don't have
to use tmp_pathbuf as often.
*/
/* cygwin internal: map sockaddr into internet domain address */
static int __unused
get_inet_addr_unix (const struct sockaddr *in, int inlen,
struct sockaddr_storage *out, int *outlen,
int *type = NULL)
GUID __cygwin_socket_guid = {
.Data1 = 0xefc1714d,
.Data2 = 0x7b19,
@ -42,17 +70,215 @@ GUID __cygwin_socket_guid = {
};
HANDLE
fhandler_socket_unix::create_abstract_link (const sun_name_t *sun,
PUNICODE_STRING pipe_name)
{
/* Check for abstract socket. */
if (inlen >= (int) sizeof (in->sa_family) + 7
&& in->sa_data[0] == '\0' && in->sa_data[1] == 'd'
&& in->sa_data[6] == '\0')
WCHAR name[MAX_PATH];
OBJECT_ATTRIBUTES attr;
NTSTATUS status;
UNICODE_STRING uname;
HANDLE fh = NULL;
PWCHAR p = wcpcpy (name, L"af-unix-");
/* NUL bytes have no special meaning in an abstract socket name, so
we assume iso-8859-1 for simplicity and transpose the string.
transform_chars_af_unix is doing just that. */
transform_chars_af_unix (p, sun->un.sun_path, sun->un_len);
RtlInitUnicodeString (&uname, name);
InitializeObjectAttributes (&attr, &uname, OBJ_CASE_INSENSITIVE,
get_shared_parent_dir (), NULL);
/* Fill symlink with name of pipe */
status = NtCreateSymbolicLinkObject (&fh, SYMBOLIC_LINK_ALL_ACCESS,
&attr, pipe_name);
if (!NT_SUCCESS (status))
{
/* TODO */
return 0;
if (status == STATUS_OBJECT_NAME_EXISTS
|| status == STATUS_OBJECT_NAME_COLLISION)
set_errno (EADDRINUSE);
else
__seterrno_from_nt_status (status);
}
return fh;
}
struct rep_pipe_name_t
{
USHORT Length;
WCHAR PipeName[1];
};
HANDLE
fhandler_socket_unix::create_reparse_point (const sun_name_t *sun,
PUNICODE_STRING pipe_name)
{
ULONG access;
HANDLE old_trans = NULL, trans = NULL;
OBJECT_ATTRIBUTES attr;
IO_STATUS_BLOCK io;
NTSTATUS status;
HANDLE fh = NULL;
PREPARSE_GUID_DATA_BUFFER rp;
rep_pipe_name_t *rep_pipe_name;
const DWORD data_len = sizeof (*rep_pipe_name) + pipe_name->Length;
path_conv pc (sun->un.sun_path, PC_SYM_FOLLOW);
if (pc.error)
{
set_errno (pc.error);
return NULL;
}
if (pc.exists ())
{
set_errno (EADDRINUSE);
return NULL;
}
/* We will overwrite the DACL after the call to NtCreateFile. This
requires READ_CONTROL and WRITE_DAC access, otherwise get_file_sd
and set_file_sd both have to open the file again.
FIXME: On remote NTFS shares open sometimes fails because even the
creator of the file doesn't have the right to change the DACL.
I don't know what setting that is or how to recognize such a share,
so for now we don't request WRITE_DAC on remote drives. */
access = DELETE | FILE_GENERIC_WRITE;
if (!pc.isremote ())
access |= READ_CONTROL | WRITE_DAC | WRITE_OWNER;
if ((pc.fs_flags () & FILE_SUPPORTS_TRANSACTIONS))
start_transaction (old_trans, trans);
retry_after_transaction_error:
status = NtCreateFile (&fh, DELETE | FILE_GENERIC_WRITE,
pc.get_object_attr (attr, sec_none_nih), &io,
NULL, FILE_ATTRIBUTE_NORMAL, 0, FILE_CREATE,
FILE_SYNCHRONOUS_IO_NONALERT
| FILE_NON_DIRECTORY_FILE
| FILE_OPEN_FOR_BACKUP_INTENT
| FILE_OPEN_REPARSE_POINT,
NULL, 0);
if (NT_TRANSACTIONAL_ERROR (status) && trans)
{
stop_transaction (status, old_trans, trans);
goto retry_after_transaction_error;
}
path_conv pc (in->sa_data, PC_SYM_FOLLOW);
if (!NT_SUCCESS (status))
{
if (io.Information == FILE_EXISTS)
set_errno (EADDRINUSE);
else
__seterrno_from_nt_status (status);
goto out;
}
rp = (PREPARSE_GUID_DATA_BUFFER)
alloca (REPARSE_GUID_DATA_BUFFER_HEADER_SIZE + data_len);
rp->ReparseTag = IO_REPARSE_TAG_CYGUNIX;
rp->ReparseDataLength = data_len;
rp->Reserved = 0;
memcpy (&rp->ReparseGuid, CYGWIN_SOCKET_GUID, sizeof (GUID));
rep_pipe_name = (rep_pipe_name_t *) rp->GenericReparseBuffer.DataBuffer;
rep_pipe_name->Length = pipe_name->Length;
memcpy (rep_pipe_name->PipeName, pipe_name->Buffer, pipe_name->Length);
rep_pipe_name->PipeName[pipe_name->Length / sizeof (WCHAR)] = L'\0';
status = NtFsControlFile (fh, NULL, NULL, NULL, &io,
FSCTL_SET_REPARSE_POINT, rp,
REPARSE_GUID_DATA_BUFFER_HEADER_SIZE
+ rp->ReparseDataLength, NULL, 0);
if (NT_SUCCESS (status))
{
set_created_file_access (fh, pc, S_IRUSR | S_IWUSR
| S_IRGRP | S_IWGRP
| S_IROTH | S_IWOTH);
NtClose (fh);
/* We don't have to keep the file open, but the caller needs to
get a value != NULL to know the file creation went fine. */
fh = INVALID_HANDLE_VALUE;
}
else if (!trans)
{
FILE_DISPOSITION_INFORMATION fdi = { TRUE };
__seterrno_from_nt_status (status);
status = NtSetInformationFile (fh, &io, &fdi, sizeof fdi,
FileDispositionInformation);
if (!NT_SUCCESS (status))
debug_printf ("Setting delete dispostion failed, status = %y",
status);
NtClose (fh);
fh = NULL;
}
out:
if (trans)
stop_transaction (status, old_trans, trans);
return fh;
}
HANDLE
fhandler_socket_unix::create_file (const sun_name_t *sun)
{
if (sun->un_len <= (socklen_t) sizeof (sa_family_t)
|| (sun->un_len == 3 && sun->un.sun_path[0] == '\0')
|| sun->un_len > (socklen_t) sizeof sun->un)
{
set_errno (EINVAL);
return NULL;
}
if (sun->un.sun_path[0] == '\0')
return create_abstract_link (sun, pc.get_nt_native_path ());
return create_reparse_point (sun, pc.get_nt_native_path ());
}
int
fhandler_socket_unix::open_abstract_link (sun_name_t *sun,
PUNICODE_STRING pipe_name)
{
WCHAR name[MAX_PATH];
OBJECT_ATTRIBUTES attr;
NTSTATUS status;
UNICODE_STRING uname;
HANDLE fh;
PWCHAR p = wcpcpy (name, L"af-unix-");
p = transform_chars_af_unix (p, sun->un.sun_path, sun->un_len);
*p = L'\0';
RtlInitUnicodeString (&uname, name);
InitializeObjectAttributes (&attr, &uname, OBJ_CASE_INSENSITIVE,
get_shared_parent_dir (), NULL);
status = NtOpenSymbolicLinkObject (&fh, SYMBOLIC_LINK_QUERY, &attr);
if (!NT_SUCCESS (status))
{
__seterrno_from_nt_status (status);
return -1;
}
if (pipe_name)
status = NtQuerySymbolicLinkObject (fh, pipe_name, NULL);
NtClose (fh);
if (pipe_name)
{
if (!NT_SUCCESS (status))
{
__seterrno_from_nt_status (status);
return -1;
}
/* Enforce NUL-terminated pipe name. */
pipe_name->Buffer[pipe_name->Length / sizeof (WCHAR)] = L'\0';
}
return 0;
}
int
fhandler_socket_unix::open_reparse_point (sun_name_t *sun,
PUNICODE_STRING pipe_name)
{
/* TODO: Open reparse point and fetch type and pipe name */
NTSTATUS status;
HANDLE fh;
OBJECT_ATTRIBUTES attr;
IO_STATUS_BLOCK io;
PREPARSE_GUID_DATA_BUFFER rp;
tmp_pathbuf tp;
path_conv pc (sun->un.sun_path, PC_SYM_FOLLOW);
if (pc.error)
{
set_errno (pc.error);
@ -63,99 +289,222 @@ HANDLE
set_errno (ENOENT);
return -1;
}
/* Do NOT test for the file being a socket file here. The socket file
creation is not an atomic operation, so there is a chance that socket
files which are just in the process of being created are recognized
as non-socket files. To work around this problem we now create the
file with all sharing disabled. If the below NtOpenFile fails
with STATUS_SHARING_VIOLATION we know that the file already exists,
but the creating process isn't finished yet. So we yield and try
again, until we can either open the file successfully, or some error
other than STATUS_SHARING_VIOLATION occurs.
Since we now don't know if the file is actually a socket file, we
perform this check here explicitely. */
NTSTATUS status;
HANDLE fh;
OBJECT_ATTRIBUTES attr;
IO_STATUS_BLOCK io;
pc.get_object_attr (attr, sec_none_nih);
do
{
status = NtOpenFile (&fh, GENERIC_READ | SYNCHRONIZE, &attr, &io,
FILE_SHARE_VALID_FLAGS,
FILE_SYNCHRONOUS_IO_NONALERT
| FILE_NON_DIRECTORY_FILE
| FILE_OPEN_FOR_BACKUP_INTENT
| FILE_NON_DIRECTORY_FILE);
| FILE_OPEN_REPARSE_POINT);
if (status == STATUS_SHARING_VIOLATION)
{
/* While we hope that the sharing violation is only temporary, we
also could easily get stuck here, waiting for a file in use by
some greedy Win32 application. Therefore we should never wait
endlessly without checking for signals and thread cancel event. */
pthread_testcancel ();
if (cygwait (NULL, cw_nowait, cw_sig_eintr) == WAIT_SIGNALED
&& !_my_tls.call_signal_handler ())
{
set_errno (EINTR);
return -1;
}
yield ();
}
{
/* While we hope that the sharing violation is only temporary, we
also could easily get stuck here, waiting for a file in use by
some greedy Win32 application. Therefore we should never wait
endlessly without checking for signals and thread cancel event. */
pthread_testcancel ();
if (cygwait (NULL, cw_nowait, cw_sig_eintr) == WAIT_SIGNALED
&& !_my_tls.call_signal_handler ())
{
set_errno (EINTR);
return -1;
}
yield ();
}
else if (!NT_SUCCESS (status))
{
__seterrno_from_nt_status (status);
return -1;
}
{
__seterrno_from_nt_status (status);
return -1;
}
}
while (status == STATUS_SHARING_VIOLATION);
/* Now test for the SYSTEM bit. */
FILE_BASIC_INFORMATION fbi;
status = NtQueryInformationFile (fh, &io, &fbi, sizeof fbi,
FileBasicInformation);
if (!NT_SUCCESS (status))
{
__seterrno_from_nt_status (status);
return -1;
}
if (!(fbi.FileAttributes & FILE_ATTRIBUTE_SYSTEM))
{
NtClose (fh);
set_errno (EBADF);
return -1;
}
/* Eventually check the content and fetch the required information. */
char buf[128];
memset (buf, 0, sizeof buf);
status = NtReadFile (fh, NULL, NULL, NULL, &io, buf, 128, NULL, NULL);
rp = (PREPARSE_GUID_DATA_BUFFER) tp.c_get ();
status = NtFsControlFile (fh, NULL, NULL, NULL, &io, FSCTL_GET_REPARSE_POINT,
NULL, 0, rp, MAXIMUM_REPARSE_DATA_BUFFER_SIZE);
NtClose (fh);
if (NT_SUCCESS (status))
if (rp->ReparseTag == IO_REPARSE_TAG_CYGUNIX
&& memcmp (CYGWIN_SOCKET_GUID, &rp->ReparseGuid, sizeof (GUID)) == 0)
{
#if 0 /* TODO */
struct sockaddr_in sin;
char ctype;
sin.sin_family = AF_INET;
if (strncmp (buf, SOCKET_COOKIE, strlen (SOCKET_COOKIE)))
if (pipe_name)
{
set_errno (EBADF);
return -1;
rep_pipe_name_t *rep_pipe_name = (rep_pipe_name_t *)
rp->GenericReparseBuffer.DataBuffer;
pipe_name->Length = rep_pipe_name->Length;
/* pipe name in reparse point is NUL-terminated */
memcpy (pipe_name->Buffer, rep_pipe_name->PipeName,
rep_pipe_name->Length + sizeof (WCHAR));
}
sscanf (buf + strlen (SOCKET_COOKIE), "%hu %c", &sin.sin_port, &ctype);
sin.sin_port = htons (sin.sin_port);
sin.sin_addr.s_addr = htonl (INADDR_LOOPBACK);
memcpy (out, &sin, sizeof sin);
*outlen = sizeof sin;
if (type)
*type = (ctype == 's' ? SOCK_STREAM :
ctype == 'd' ? SOCK_DGRAM
: 0);
#endif
return 0;
}
__seterrno_from_nt_status (status);
return -1;
}
int
fhandler_socket_unix::open_file (sun_name_t *sun, int &type,
PUNICODE_STRING pipe_name)
{
int ret = -1;
if (sun->un_len <= (socklen_t) sizeof (sa_family_t)
|| (sun->un_len == 3 && sun->un.sun_path[0] == '\0')
|| sun->un_len > (socklen_t) sizeof sun->un)
set_errno (EINVAL);
else if (sun->un.sun_path[0] == '\0')
ret = open_abstract_link (sun, pipe_name);
else
ret = open_reparse_point (sun, pipe_name);
if (!ret)
switch (pipe_name->Buffer[38])
{
case 'd':
type = SOCK_DGRAM;
break;
case 's':
type = SOCK_STREAM;
break;
default:
set_errno (EINVAL);
ret = -1;
break;
}
return ret;
}
HANDLE
fhandler_socket_unix::autobind (sun_name_t* sun)
{
uint32_t id;
HANDLE fh;
do
{
/* Use only 5 hex digits (up to 2^20 sockets) for Linux compat */
set_unique_id ();
id = get_unique_id () & 0xfffff;
sun->un.sun_path[0] = '\0';
sun->un_len = sizeof (sa_family_t)
+ 1 /* leading NUL */
+ __small_sprintf (sun->un.sun_path + 1, "%5X", id);
}
while ((fh = create_abstract_link (sun, pc.get_nt_native_path ())) == NULL);
return fh;
}
wchar_t
fhandler_socket_unix::get_type_char ()
{
switch (get_socket_type ())
{
case SOCK_STREAM:
return 's';
case SOCK_DGRAM:
return 'd';
default:
return '?';
}
}
void
fhandler_socket_unix::gen_pipe_name ()
{
WCHAR pipe_name_buf[MAX_PATH];
UNICODE_STRING pipe_name;
__small_swprintf (pipe_name_buf,
L"\\Device\\NamedPipe\\cygwin-%S-unix-%C-%016_X",
&cygheap->installation_key,
get_type_char (),
get_plain_ino ());
RtlInitUnicodeString (&pipe_name, pipe_name_buf);
pc.set_nt_native_path (&pipe_name);
}
void
fhandler_socket_unix::set_wait_state (DWORD wait_state)
{
if (get_handle ())
{
NTSTATUS status;
IO_STATUS_BLOCK io;
FILE_PIPE_INFORMATION fpi;
fpi.ReadMode = FILE_PIPE_MESSAGE_MODE;
fpi.CompletionMode = wait_state;
status = NtSetInformationFile (get_handle (), &io, &fpi, sizeof fpi,
FilePipeInformation);
if (!NT_SUCCESS (status))
system_printf ("NtSetInformationFile(FilePipeInformation): %y", status);
}
}
HANDLE
fhandler_socket_unix::create_pipe ()
{
NTSTATUS status;
HANDLE ph;
ACCESS_MASK access;
OBJECT_ATTRIBUTES attr;
IO_STATUS_BLOCK io;
ULONG sharing;
ULONG nonblocking;
ULONG max_instances;
LARGE_INTEGER timeout;
access = GENERIC_READ | GENERIC_WRITE | SYNCHRONIZE;
sharing = FILE_SHARE_READ | FILE_SHARE_WRITE;
InitializeObjectAttributes (&attr, pc.get_nt_native_path (), OBJ_INHERIT,
NULL, NULL);
nonblocking = is_nonblocking () ? FILE_PIPE_COMPLETE_OPERATION
: FILE_PIPE_QUEUE_OPERATION;
max_instances = (get_socket_type () == SOCK_DGRAM) ? 1 : -1;
timeout.QuadPart = -500000;
status = NtCreateNamedPipeFile (&ph, access, &attr, &io, sharing,
FILE_CREATE, FILE_SYNCHRONOUS_IO_NONALERT,
FILE_PIPE_MESSAGE_TYPE,
FILE_PIPE_MESSAGE_MODE,
nonblocking, max_instances,
PREFERRED_IO_BLKSIZE, PREFERRED_IO_BLKSIZE,
&timeout);
if (!NT_SUCCESS (status))
system_printf ("NtCreateNamedPipeFile: %y", status);
return ph;
}
HANDLE
fhandler_socket_unix::create_pipe_instance ()
{
NTSTATUS status;
HANDLE ph;
ACCESS_MASK access;
OBJECT_ATTRIBUTES attr;
IO_STATUS_BLOCK io;
ULONG sharing;
ULONG nonblocking;
ULONG max_instances;
LARGE_INTEGER timeout;
access = GENERIC_READ | GENERIC_WRITE | SYNCHRONIZE;
sharing = FILE_SHARE_READ | FILE_SHARE_WRITE;
InitializeObjectAttributes (&attr, pc.get_nt_native_path (), OBJ_INHERIT,
NULL, NULL);
nonblocking = is_nonblocking () ? FILE_PIPE_COMPLETE_OPERATION
: FILE_PIPE_QUEUE_OPERATION;
max_instances = (get_socket_type () == SOCK_DGRAM) ? 1 : -1;
timeout.QuadPart = -500000;
status = NtCreateNamedPipeFile (&ph, access, &attr, &io, sharing,
FILE_OPEN, FILE_SYNCHRONOUS_IO_NONALERT,
FILE_PIPE_MESSAGE_TYPE,
FILE_PIPE_MESSAGE_MODE,
nonblocking, max_instances,
PREFERRED_IO_BLKSIZE, PREFERRED_IO_BLKSIZE,
&timeout);
if (!NT_SUCCESS (status))
system_printf ("NtCreateNamedPipeFile: %y", status);
return ph;
}
fhandler_socket_unix::fhandler_socket_unix () :
sun_path (NULL),
peer_sun_path (NULL)
@ -218,8 +567,16 @@ fhandler_socket_unix::socket (int af, int type, int protocol, int flags)
set_errno (EPROTONOSUPPORT);
return -1;
}
set_errno (EAFNOSUPPORT);
return -1;
set_addr_family (af);
set_socket_type (type);
if (flags & SOCK_NONBLOCK)
set_nonblocking (true);
if (flags & SOCK_CLOEXEC)
set_close_on_exec (true);
set_io_handle (NULL);
set_unique_id ();
set_ino (get_unique_id ());
return 0;
}
int
@ -243,7 +600,34 @@ fhandler_socket_unix::socketpair (int af, int type, int protocol, int flags,
int
fhandler_socket_unix::bind (const struct sockaddr *name, int namelen)
{
set_errno (EAFNOSUPPORT);
__try
{
sun_name_t sun (name, namelen);
bool unnamed = (sun.un_len == sizeof sun.un.sun_family);
HANDLE pipe = NULL;
if (get_handle ())
{
set_errno (EINVAL);
__leave;
}
gen_pipe_name ();
pipe = create_pipe ();
if (pipe)
{
file = unnamed ? autobind (&sun) : create_file (&sun);
if (!file)
{
NtClose (pipe);
__leave;
}
set_io_handle (pipe);
set_sun_path (&sun);
return 0;
}
}
__except (EFAULT) {}
__endtry
return -1;
}
@ -312,8 +696,11 @@ fhandler_socket_unix::shutdown (int how)
int
fhandler_socket_unix::close ()
{
set_errno (EAFNOSUPPORT);
return -1;
if (get_handle ())
NtClose (get_handle ());
if (file && file != INVALID_HANDLE_VALUE)
NtClose (file);
return 0;
}
int