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Cygwin: AF_UNIX: grab_admin_pkg: refactor

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Extract from grab_admin_pkg two new methods, record_shut_info and
process_admin_pkg.  Also add a new 'peek' argument to grab_admin_pkg.
If this is true, peek to see if the next packet in the pipe is an
administrative packet.  Otherwise, assume we already know it is.
This commit is contained in:
Ken Brown 2020-10-19 09:52:51 -04:00
parent c60fcf1116
commit 99490d2825
2 changed files with 79 additions and 59 deletions
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4
winsup/cygwin/fhandler.h
View File

@ -1055,7 +1055,9 @@ class fhandler_socket_unix : public fhandler_socket
wchar_t get_type_char (); wchar_t get_type_char ();
void set_pipe_non_blocking (bool nonblocking); void set_pipe_non_blocking (bool nonblocking);
int send_sock_info (bool from_bind); int send_sock_info (bool from_bind);
int grab_admin_pkg (); void record_shut_info (af_unix_pkt_hdr_t *packet);
void process_admin_pkt (af_unix_pkt_hdr_t *packet);
int grab_admin_pkt (bool peek = true);
int recv_peer_info (); int recv_peer_info ();
static NTSTATUS npfs_handle (HANDLE &nph); static NTSTATUS npfs_handle (HANDLE &nph);
HANDLE create_pipe (bool single_instance); HANDLE create_pipe (bool single_instance);

134
winsup/cygwin/fhandler_socket_unix.cc
View File

@ -76,10 +76,10 @@ GUID __cygwin_socket_guid = {
for the entire packet, as well as for all three data blocks. The for the entire packet, as well as for all three data blocks. The
combined maximum size of a packet is 64K, including the header. combined maximum size of a packet is 64K, including the header.
A connecting, bound STREAM socket sends it's local sun_path once after A connecting, bound STREAM socket sends its local sun_path once after
a successful connect. An already connected socket also sends its local a successful connect. An already connected socket also sends its local
sun_path after a successful bind (border case, but still...). These sun_path after a successful bind (border case, but still...). These
packages don't contain any other data (cmsg_len == 0, data_len == 0). packets don't contain any other data (cmsg_len == 0, data_len == 0).
A bound DGRAM socket sends its sun_path with each sendmsg/sendto. A bound DGRAM socket sends its sun_path with each sendmsg/sendto.
*/ */
@ -90,7 +90,7 @@ class af_unix_pkt_hdr_t
{ {
public: public:
uint16_t pckt_len; /* size of packet including header */ uint16_t pckt_len; /* size of packet including header */
bool admin_pkg : 1; /* admin packets are marked as such */ bool admin_pkt : 1; /* admin packets are marked as such */
shut_state shut_info : 2; /* _SHUT_RECV /_SHUT_SEND. */ shut_state shut_info : 2; /* _SHUT_RECV /_SHUT_SEND. */
uint8_t name_len; /* size of name, a sockaddr_un */ uint8_t name_len; /* size of name, a sockaddr_un */
uint16_t cmsg_len; /* size of ancillary data block */ uint16_t cmsg_len; /* size of ancillary data block */
@ -100,7 +100,7 @@ class af_unix_pkt_hdr_t
{ init (a, s, n, c, d); } { init (a, s, n, c, d); }
void init (bool a, shut_state s, uint8_t n, uint16_t c, uint16_t d) void init (bool a, shut_state s, uint8_t n, uint16_t c, uint16_t d)
{ {
admin_pkg = a; admin_pkt = a;
shut_info = s; shut_info = s;
name_len = n; name_len = n;
cmsg_len = c; cmsg_len = c;
@ -710,73 +710,91 @@ fhandler_socket_unix::send_sock_info (bool from_bind)
return 0; return 0;
} }
/* Checks if the next packet in the pipe is an administrative packet. void
If so, it reads it from the pipe, handles it. Returns an error code. */ fhandler_socket_unix::record_shut_info (af_unix_pkt_hdr_t *packet)
{
if (packet->shut_info)
{
state_lock ();
/* Peer's shutdown sends the SHUT flags as used by the peer.
They have to be reversed for our side. */
int shut_info = saw_shutdown ();
if (packet->shut_info & _SHUT_RECV)
shut_info |= _SHUT_SEND;
if (packet->shut_info & _SHUT_SEND)
shut_info |= _SHUT_RECV;
saw_shutdown (shut_info);
/* FIXME: anything else here? */
state_unlock ();
}
}
void
fhandler_socket_unix::process_admin_pkt (af_unix_pkt_hdr_t *packet)
{
record_shut_info (packet);
state_lock ();
if (packet->name_len > 0)
peer_sun_path (AF_UNIX_PKT_NAME (packet), packet->name_len);
if (packet->cmsg_len > 0)
{
struct cmsghdr *cmsg = (struct cmsghdr *)
alloca (packet->cmsg_len);
memcpy (cmsg, AF_UNIX_PKT_CMSG (packet), packet->cmsg_len);
if (cmsg->cmsg_level == SOL_SOCKET
&& cmsg->cmsg_type == SCM_CREDENTIALS)
peer_cred ((struct ucred *) CMSG_DATA(cmsg));
}
state_unlock ();
}
/* Reads an administrative packet from the pipe and handles it. If
PEEK is true, checks first to see if the next packet in the pipe is
an administrative packet; otherwise the caller must check this.
Returns an error code.
FIXME: Currently we always return 0, and no callers check for error. */
int int
fhandler_socket_unix::grab_admin_pkg () fhandler_socket_unix::grab_admin_pkt (bool peek)
{ {
HANDLE evt; HANDLE evt;
NTSTATUS status; NTSTATUS status;
IO_STATUS_BLOCK io; IO_STATUS_BLOCK io;
/* MAX_PATH is more than sufficient for admin packets. */ /* MAX_PATH is more than sufficient for admin packets. */
PFILE_PIPE_PEEK_BUFFER pbuf = (PFILE_PIPE_PEEK_BUFFER) alloca (MAX_PATH); void *buffer = alloca (MAX_PATH);
af_unix_pkt_hdr_t *packet;
if (!(evt = create_event ())) if (!(evt = create_event ()))
return 0; return 0;
io_lock (); if (peek)
ULONG ret_len;
status = peek_pipe (pbuf, MAX_PATH, evt, ret_len);
/* FIXME: Check status and handle error. */
if (pbuf->NumberOfMessages == 0 || ret_len < sizeof (af_unix_pkt_hdr_t))
{ {
PFILE_PIPE_PEEK_BUFFER pbuf = (PFILE_PIPE_PEEK_BUFFER) buffer;
io_lock ();
ULONG ret_len;
status = peek_pipe (pbuf, MAX_PATH, evt, ret_len);
/* FIXME: Check status and handle error? */
io_unlock (); io_unlock ();
NtClose (evt); packet = (af_unix_pkt_hdr_t *) pbuf->Data;
return 0; if (pbuf->NumberOfMessages == 0 || ret_len < sizeof (af_unix_pkt_hdr_t)
|| !packet->admin_pkt)
goto out;
} }
af_unix_pkt_hdr_t *packet = (af_unix_pkt_hdr_t *) pbuf->Data;
if (!packet->admin_pkg)
io_unlock ();
else else
packet = (af_unix_pkt_hdr_t *) buffer;
io_lock ();
status = NtReadFile (get_handle (), evt, NULL, NULL, &io, packet,
MAX_PATH, NULL, NULL);
if (status == STATUS_PENDING)
{ {
packet = (af_unix_pkt_hdr_t *) pbuf; /* Very short-lived */
status = NtReadFile (get_handle (), evt, NULL, NULL, &io, packet, status = NtWaitForSingleObject (evt, FALSE, NULL);
MAX_PATH, NULL, NULL);
if (status == STATUS_PENDING)
{
/* Very short-lived */
status = NtWaitForSingleObject (evt, FALSE, NULL);
if (NT_SUCCESS (status))
status = io.Status;
}
io_unlock ();
if (NT_SUCCESS (status)) if (NT_SUCCESS (status))
{ status = io.Status;
state_lock ();
if (packet->shut_info)
{
/* Peer's shutdown sends the SHUT flags as used by the peer.
They have to be reversed for our side. */
int shut_info = saw_shutdown ();
if (packet->shut_info & _SHUT_RECV)
shut_info |= _SHUT_SEND;
if (packet->shut_info & _SHUT_SEND)
shut_info |= _SHUT_RECV;
saw_shutdown (shut_info);
/* FIXME: anything else here? */
}
if (packet->name_len > 0)
peer_sun_path (AF_UNIX_PKT_NAME (packet), packet->name_len);
if (packet->cmsg_len > 0)
{
struct cmsghdr *cmsg = (struct cmsghdr *)
alloca (packet->cmsg_len);
memcpy (cmsg, AF_UNIX_PKT_CMSG (packet), packet->cmsg_len);
if (cmsg->cmsg_level == SOL_SOCKET
&& cmsg->cmsg_type == SCM_CREDENTIALS)
peer_cred ((struct ucred *) CMSG_DATA(cmsg));
}
state_unlock ();
}
} }
io_unlock ();
if (NT_SUCCESS (status))
process_admin_pkt (packet);
out:
NtClose (evt); NtClose (evt);
return 0; return 0;
} }
@ -1848,7 +1866,7 @@ fhandler_socket_unix::shutdown (int how)
{ {
/* Send shutdown info to peer. Note that it's not necessarily fatal /* Send shutdown info to peer. Note that it's not necessarily fatal
if the info isn't sent here. The info will be reproduced by any if the info isn't sent here. The info will be reproduced by any
followup package sent to the peer. */ followup packet sent to the peer. */
af_unix_pkt_hdr_t packet (true, (shut_state) new_shutdown_mask, 0, 0, 0); af_unix_pkt_hdr_t packet (true, (shut_state) new_shutdown_mask, 0, 0, 0);
io_lock (); io_lock ();
set_pipe_non_blocking (true); set_pipe_non_blocking (true);
@ -1936,7 +1954,7 @@ fhandler_socket_unix::evaluate_cmsg_data (af_unix_pkt_hdr_t *packet,
return true; return true;
} }
/* FIXME: Should recvmsg call grab_admin_pkg at appropriate places to /* FIXME: Should recvmsg call grab_admin_pkt at appropriate places to
check whether peer has called shutdown? */ check whether peer has called shutdown? */
ssize_t ssize_t
fhandler_socket_unix::recvmsg (struct msghdr *msg, int flags) fhandler_socket_unix::recvmsg (struct msghdr *msg, int flags)