| /* Replacement for mach_msg used in interruptible Hurd RPCs. |
| Copyright (C) 1995-2016 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 Lesser General Public |
| License as published by the Free Software Foundation; either |
| version 2.1 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 |
| Lesser General Public License for more details. |
| |
| You should have received a copy of the GNU Lesser General Public |
| License along with the GNU C Library; if not, see |
| <http://www.gnu.org/licenses/>. */ |
| |
| #include <mach.h> |
| #include <mach/mig_errors.h> |
| #include <mach/mig_support.h> |
| #include <hurd/signal.h> |
| #include <assert.h> |
| |
| #include "intr-msg.h" |
| |
| #ifdef NDR_CHAR_ASCII /* OSF Mach flavors have different names. */ |
| # define mig_reply_header_t mig_reply_error_t |
| #endif |
| |
| error_t |
| _hurd_intr_rpc_mach_msg (mach_msg_header_t *msg, |
| mach_msg_option_t option, |
| mach_msg_size_t send_size, |
| mach_msg_size_t rcv_size, |
| mach_port_t rcv_name, |
| mach_msg_timeout_t timeout, |
| mach_port_t notify) |
| { |
| error_t err; |
| struct hurd_sigstate *ss; |
| const mach_msg_option_t user_option = option; |
| const mach_msg_timeout_t user_timeout = timeout; |
| |
| struct clobber |
| { |
| #ifdef NDR_CHAR_ASCII |
| NDR_record_t ndr; |
| #else |
| mach_msg_type_t type; |
| #endif |
| error_t err; |
| }; |
| union msg |
| { |
| mach_msg_header_t header; |
| mig_reply_header_t reply; |
| struct |
| { |
| mach_msg_header_t header; |
| #ifdef NDR_CHAR_ASCII |
| NDR_record_t ndr; |
| #else |
| int type; |
| #endif |
| int code; |
| } check; |
| struct |
| { |
| mach_msg_header_t header; |
| struct clobber data; |
| } request; |
| }; |
| union msg *const m = (void *) msg; |
| mach_msg_bits_t msgh_bits; |
| mach_port_t remote_port; |
| mach_msg_id_t msgid; |
| struct clobber save_data; |
| |
| if ((option & (MACH_SEND_MSG|MACH_RCV_MSG)) != (MACH_SEND_MSG|MACH_RCV_MSG) |
| || _hurd_msgport_thread == MACH_PORT_NULL) |
| { |
| /* Either this is not an RPC (i.e., only a send or only a receive), |
| so it can't be interruptible; or, the signal thread is not set up |
| yet, so we cannot do the normal signal magic. Do a normal, |
| uninterruptible mach_msg call instead. */ |
| return __mach_msg (&m->header, option, send_size, rcv_size, rcv_name, |
| timeout, notify); |
| } |
| |
| ss = _hurd_self_sigstate (); |
| |
| /* Save state that gets clobbered by an EINTR reply message. |
| We will need to restore it if we want to retry the RPC. */ |
| msgh_bits = m->header.msgh_bits; |
| remote_port = m->header.msgh_remote_port; |
| msgid = m->header.msgh_id; |
| assert (rcv_size >= sizeof m->request); |
| save_data = m->request.data; |
| |
| /* Tell the signal thread that we are doing an interruptible RPC on |
| this port. If we get a signal and should return EINTR, the signal |
| thread will set this variable to MACH_PORT_NULL. The RPC might |
| return EINTR when some other thread gets a signal, in which case we |
| want to restart our call. */ |
| ss->intr_port = m->header.msgh_remote_port; |
| |
| /* A signal may arrive here, after intr_port is set, but before the |
| mach_msg system call. The signal handler might do an interruptible |
| RPC, and clobber intr_port; then it would not be set properly when we |
| actually did send the RPC, and a later signal wouldn't interrupt that |
| RPC. So, _hurd_setup_sighandler saves intr_port in the sigcontext, |
| and sigreturn restores it. */ |
| |
| message: |
| |
| /* XXX |
| At all points here (once SS->intr_port is set), the signal thread |
| thinks we are "about to enter the syscall", and might mutate our |
| return-value register. This is bogus. |
| */ |
| |
| if (ss->cancel) |
| { |
| /* We have been cancelled. Don't do an RPC at all. */ |
| ss->intr_port = MACH_PORT_NULL; |
| ss->cancel = 0; |
| return EINTR; |
| } |
| |
| /* Note that the signal trampoline code might modify our OPTION! */ |
| err = INTR_MSG_TRAP (msg, option, send_size, |
| rcv_size, rcv_name, timeout, notify); |
| |
| switch (err) |
| { |
| case MACH_RCV_TIMED_OUT: |
| if (user_option & MACH_RCV_TIMEOUT) |
| /* The real user RPC timed out. */ |
| break; |
| else |
| /* The operation was supposedly interrupted, but still has |
| not returned. Declare it interrupted. */ |
| goto interrupted; |
| |
| case MACH_SEND_INTERRUPTED: /* RPC didn't get out. */ |
| if (!(option & MACH_SEND_MSG)) |
| { |
| /* Oh yes, it did! Since we were not doing a message send, |
| this return code cannot have come from the kernel! |
| Instead, it was the signal thread mutating our state to tell |
| us not to enter this RPC. However, we are already in the receive! |
| Since the signal thread thought we weren't in the RPC yet, |
| it didn't do an interrupt_operation. |
| XXX */ |
| goto retry_receive; |
| } |
| /* FALLTHROUGH */ |
| |
| /* These are the other codes that mean a pseudo-receive modified |
| the message buffer and we might need to clean up the port rights. */ |
| case MACH_SEND_TIMED_OUT: |
| case MACH_SEND_INVALID_NOTIFY: |
| #ifdef MACH_SEND_NO_NOTIFY |
| case MACH_SEND_NO_NOTIFY: |
| #endif |
| #ifdef MACH_SEND_NOTIFY_IN_PROGRESS |
| case MACH_SEND_NOTIFY_IN_PROGRESS: |
| #endif |
| if (MACH_MSGH_BITS_REMOTE (msg->msgh_bits) == MACH_MSG_TYPE_MOVE_SEND) |
| { |
| __mach_port_deallocate (__mach_task_self (), msg->msgh_remote_port); |
| msg->msgh_bits |
| = (MACH_MSGH_BITS (MACH_MSG_TYPE_COPY_SEND, |
| MACH_MSGH_BITS_LOCAL (msg->msgh_bits)) |
| | MACH_MSGH_BITS_OTHER (msg->msgh_bits)); |
| } |
| if (msg->msgh_bits & MACH_MSGH_BITS_COMPLEX) |
| { |
| #ifndef MACH_MSG_PORT_DESCRIPTOR |
| /* Check for MOVE_SEND rights in the message. These hold refs |
| that we need to release in case the message is in fact never |
| re-sent later. Since it might in fact be re-sent, we turn |
| these into COPY_SEND's after deallocating the extra user ref; |
| the caller is responsible for still holding a ref to go with |
| the original COPY_SEND right, so the resend copies it again. */ |
| |
| mach_msg_type_long_t *ty = (void *) (msg + 1); |
| while ((void *) ty < (void *) msg + msg->msgh_size) |
| { |
| mach_msg_type_name_t name; |
| mach_msg_type_size_t size; |
| mach_msg_type_number_t number; |
| |
| inline void clean_ports (mach_port_t *ports, int dealloc) |
| { |
| mach_msg_type_number_t i; |
| switch (name) |
| { |
| case MACH_MSG_TYPE_MOVE_SEND: |
| for (i = 0; i < number; i++) |
| __mach_port_deallocate (__mach_task_self (), *ports++); |
| if (ty->msgtl_header.msgt_longform) |
| ty->msgtl_name = MACH_MSG_TYPE_COPY_SEND; |
| else |
| ty->msgtl_header.msgt_name = MACH_MSG_TYPE_COPY_SEND; |
| break; |
| case MACH_MSG_TYPE_COPY_SEND: |
| case MACH_MSG_TYPE_MOVE_RECEIVE: |
| break; |
| default: |
| if (MACH_MSG_TYPE_PORT_ANY (name)) |
| assert (! "unexpected port type in interruptible RPC"); |
| } |
| if (dealloc) |
| __vm_deallocate (__mach_task_self (), |
| (vm_address_t) ports, |
| number * sizeof (mach_port_t)); |
| } |
| |
| if (ty->msgtl_header.msgt_longform) |
| { |
| name = ty->msgtl_name; |
| size = ty->msgtl_size; |
| number = ty->msgtl_number; |
| ty = (void *) ty + sizeof (mach_msg_type_long_t); |
| } |
| else |
| { |
| name = ty->msgtl_header.msgt_name; |
| size = ty->msgtl_header.msgt_size; |
| number = ty->msgtl_header.msgt_number; |
| ty = (void *) ty + sizeof (mach_msg_type_t); |
| } |
| |
| if (ty->msgtl_header.msgt_inline) |
| { |
| clean_ports ((void *) ty, 0); |
| /* calculate length of data in bytes, rounding up */ |
| ty = (void *) ty + (((((number * size) + 7) >> 3) |
| + sizeof (mach_msg_type_t) - 1) |
| &~ (sizeof (mach_msg_type_t) - 1)); |
| } |
| else |
| { |
| clean_ports (*(void **) ty, |
| ty->msgtl_header.msgt_deallocate); |
| ty = (void *) ty + sizeof (void *); |
| } |
| } |
| #else /* Untyped Mach IPC flavor. */ |
| mach_msg_body_t *body = (void *) (msg + 1); |
| mach_msg_descriptor_t *desc = (void *) (body + 1); |
| mach_msg_descriptor_t *desc_end = desc + body->msgh_descriptor_count; |
| for (; desc < desc_end; ++desc) |
| switch (desc->type.type) |
| { |
| case MACH_MSG_PORT_DESCRIPTOR: |
| switch (desc->port.disposition) |
| { |
| case MACH_MSG_TYPE_MOVE_SEND: |
| __mach_port_deallocate (mach_task_self (), |
| desc->port.name); |
| desc->port.disposition = MACH_MSG_TYPE_COPY_SEND; |
| break; |
| case MACH_MSG_TYPE_COPY_SEND: |
| case MACH_MSG_TYPE_MOVE_RECEIVE: |
| break; |
| default: |
| assert (! "unexpected port type in interruptible RPC"); |
| } |
| break; |
| case MACH_MSG_OOL_DESCRIPTOR: |
| if (desc->out_of_line.deallocate) |
| __vm_deallocate (__mach_task_self (), |
| (vm_address_t) desc->out_of_line.address, |
| desc->out_of_line.size); |
| break; |
| case MACH_MSG_OOL_PORTS_DESCRIPTOR: |
| switch (desc->ool_ports.disposition) |
| { |
| case MACH_MSG_TYPE_MOVE_SEND: |
| { |
| mach_msg_size_t i; |
| const mach_port_t *ports = desc->ool_ports.address; |
| for (i = 0; i < desc->ool_ports.count; ++i) |
| __mach_port_deallocate (__mach_task_self (), ports[i]); |
| desc->ool_ports.disposition = MACH_MSG_TYPE_COPY_SEND; |
| break; |
| } |
| case MACH_MSG_TYPE_COPY_SEND: |
| case MACH_MSG_TYPE_MOVE_RECEIVE: |
| break; |
| default: |
| assert (! "unexpected port type in interruptible RPC"); |
| } |
| if (desc->ool_ports.deallocate) |
| __vm_deallocate (__mach_task_self (), |
| (vm_address_t) desc->ool_ports.address, |
| desc->ool_ports.count |
| * sizeof (mach_port_t)); |
| break; |
| default: |
| assert (! "unexpected descriptor type in interruptible RPC"); |
| } |
| #endif |
| } |
| break; |
| |
| case EINTR: |
| /* Either the process was stopped and continued, |
| or the server doesn't support interrupt_operation. */ |
| if (ss->intr_port != MACH_PORT_NULL) |
| /* If this signal was for us and it should interrupt calls, the |
| signal thread will have cleared SS->intr_port. |
| Since it's not cleared, the signal was for another thread, |
| or SA_RESTART is set. Restart the interrupted call. */ |
| { |
| /* Make sure we have a valid reply port. The one we were using |
| may have been destroyed by interruption. */ |
| m->header.msgh_local_port = rcv_name = __mig_get_reply_port (); |
| m->header.msgh_bits = msgh_bits; |
| option = user_option; |
| timeout = user_timeout; |
| goto message; |
| } |
| /* FALLTHROUGH */ |
| |
| case MACH_RCV_PORT_DIED: |
| /* Server didn't respond to interrupt_operation, |
| so the signal thread destroyed the reply port. */ |
| /* FALLTHROUGH */ |
| |
| interrupted: |
| err = EINTR; |
| |
| /* The EINTR return indicates cancellation, so clear the flag. */ |
| ss->cancel = 0; |
| break; |
| |
| case MACH_RCV_INTERRUPTED: /* RPC sent; no reply. */ |
| option &= ~MACH_SEND_MSG; /* Don't send again. */ |
| retry_receive: |
| if (ss->intr_port == MACH_PORT_NULL) |
| { |
| /* This signal or cancellation was for us. We need to wait for |
| the reply, but not hang forever. */ |
| option |= MACH_RCV_TIMEOUT; |
| /* Never decrease the user's timeout. */ |
| if (!(user_option & MACH_RCV_TIMEOUT) |
| || timeout > _hurd_interrupted_rpc_timeout) |
| timeout = _hurd_interrupted_rpc_timeout; |
| } |
| else |
| { |
| option = user_option; |
| timeout = user_timeout; |
| } |
| goto message; /* Retry the receive. */ |
| |
| case MACH_MSG_SUCCESS: |
| { |
| /* We got a reply. Was it EINTR? */ |
| #ifdef MACH_MSG_TYPE_BIT |
| const union |
| { |
| mach_msg_type_t t; |
| int i; |
| } check = |
| { t: { MACH_MSG_TYPE_INTEGER_T, sizeof (integer_t) * 8, |
| 1, TRUE, FALSE, FALSE, 0 } }; |
| #endif |
| |
| if (m->reply.RetCode == EINTR && |
| m->header.msgh_size == sizeof m->reply && |
| #ifdef MACH_MSG_TYPE_BIT |
| m->check.type == check.i && |
| #endif |
| !(m->header.msgh_bits & MACH_MSGH_BITS_COMPLEX)) |
| { |
| /* It is indeed EINTR. Is the interrupt for us? */ |
| if (ss->intr_port != MACH_PORT_NULL) |
| { |
| /* Nope; repeat the RPC. |
| XXX Resources moved? */ |
| |
| assert (m->header.msgh_id == msgid + 100); |
| |
| /* We know we have a valid reply port, because we just |
| received the EINTR reply on it. Restore it and the |
| other fields in the message header needed for send, |
| since the header now reflects receipt of the reply. */ |
| m->header.msgh_local_port = rcv_name; |
| m->header.msgh_remote_port = remote_port; |
| m->header.msgh_id = msgid; |
| m->header.msgh_bits = msgh_bits; |
| /* Restore the two words clobbered by the reply data. */ |
| m->request.data = save_data; |
| |
| /* Restore the original mach_msg options. |
| OPTION may have had MACH_RCV_TIMEOUT added, |
| and/or MACH_SEND_MSG removed. */ |
| option = user_option; |
| timeout = user_timeout; |
| |
| /* Now we are ready to repeat the original message send. */ |
| goto message; |
| } |
| else |
| /* The EINTR return indicates cancellation, |
| so clear the flag. */ |
| ss->cancel = 0; |
| } |
| } |
| break; |
| |
| default: /* Quiet -Wswitch-enum. */ |
| break; |
| } |
| |
| ss->intr_port = MACH_PORT_NULL; |
| |
| return err; |
| } |