about summary refs log tree commit diff
path: root/hurd/report-wait.c
blob: a02d2b38ed84f01c41715b69e83620a5bf1b8c7c (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
/* Report on what a thread in our task is waiting for.
   Copyright (C) 1996-2021 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
   <https://www.gnu.org/licenses/>.  */

#include <hurd.h>
#include <hurd/signal.h>
#include <hurd/fd.h>
#include <string.h>
#include <assert.h>
#include <hurd/msg_server.h>
#include <thread_state.h>
#include <intr-msg.h>

static char *
describe_number (char *description, const char *flavor, long int i, size_t size)
{
  unsigned long int j;
  char *limit = description + size;
  char *p = flavor == NULL ? description : __stpncpy (description, flavor, size);
  char *end;

  if (p == limit)
    return p;

  /* Handle sign.  */
  if (i < 0)
    {
      i = -i;
      *p++ = '-';
    }

  if (p == limit)
    return p;

  /* Allocate space for the number at the end of DESCRIPTION.  */
  for (j = i; j >= 10; j /= 10)
    p++;
  end = p + 1;

  if (end < limit)
    *end = '\0';
  else
    end = limit;

  do
    {
      if (p < limit)
	*p = '0' + i % 10;
      p--;
      i /= 10;
    } while (i != 0);

  return end;
}

static char *
describe_port (char *description, mach_port_t port, size_t size)
{
  int i;

  if (port == MACH_PORT_NULL)
    return __stpncpy (description, "(null)", size);
  if (port == MACH_PORT_DEAD)
    return __stpncpy (description, "(dead)", size);

  if (port == __mach_task_self ())
    return __stpncpy (description, "task-self", size);

  for (i = 0; i < _hurd_nports; ++i)
    if (port == _hurd_ports[i].port)
      return describe_number (description, "init#", i, size);

  if (_hurd_init_dtable)
    {
      for (i = 0; i < _hurd_init_dtablesize; ++i)
	if (port == _hurd_init_dtable[i])
	  return describe_number (description, "fd#", i, size);
    }
  if (_hurd_dtable)
    {
      for (i = 0; i < _hurd_dtablesize; ++i)
	if (_hurd_dtable[i] == NULL)
	  continue;
	else if (port == _hurd_dtable[i]->port.port)
	  return describe_number (description, "fd#", i, size);
	else if (port == _hurd_dtable[i]->ctty.port)
	  return describe_number (description, "bgfd#", i, size);
    }

  return describe_number (description, "port#", port, size);
}


/* We want _HURD_ITIMER_THREAD, but don't want to link in the itimer code
   unnecessarily.  */
extern thread_t _hurd_itimer_thread; /* XXX */
weak_extern (_hurd_itimer_thread)

kern_return_t
_S_msg_report_wait (mach_port_t msgport, thread_t thread,
		    string_t description, mach_msg_id_t *msgid)
{
  char *limit = description + 1024; /* XXX */
  char *cur = description;
  *msgid = 0;

  if (thread == _hurd_msgport_thread)
    /* Cute.  */
    cur = __stpncpy (cur, "msgport", limit - cur);
  else if (&_hurd_itimer_thread && thread == _hurd_itimer_thread)
    cur = __stpncpy (cur, "itimer", limit - cur);
  else
    {
      /* Make sure this is really one of our threads.  */

      struct hurd_sigstate *ss;

      __mutex_lock (&_hurd_siglock);
      for (ss = _hurd_sigstates; ss != NULL; ss = ss->next)
	if (ss->thread == thread)
	  break;
      __mutex_unlock (&_hurd_siglock);
      if (ss == NULL)
	/* To hell with you.  */
	return EINVAL;

      if (ss->suspended != MACH_PORT_NULL)
	cur = __stpncpy (cur, "sigsuspend", limit - cur);
      else
	{
	  /* Examine the thread's state to see if it is blocked in an RPC.  */

	  struct machine_thread_state state;
	  mach_msg_type_number_t count = MACHINE_THREAD_STATE_COUNT;
	  error_t err;

	  err = __thread_get_state (thread, MACHINE_THREAD_STATE_FLAVOR,
				    (natural_t *) &state, &count);
	  if (err)
	    return err;
	  assert (count == MACHINE_THREAD_STATE_COUNT);
	  if (SYSCALL_EXAMINE (&state, msgid))
	    {
	      mach_port_t send_port, rcv_port;
	      mach_msg_option_t option;
	      mach_msg_timeout_t timeout;

	      /* Blocked in a system call.  */
	      if (*msgid == -25
		  /* mach_msg system call.  Examine its parameters.  */
		  && MSG_EXAMINE (&state, msgid, &rcv_port, &send_port,
				  &option, &timeout) == 0)
		{
		  if (send_port != MACH_PORT_NULL && *msgid != 0)
		    {
		      /* For the normal case of RPCs, we consider the
			 destination port to be the interesting thing
			 whether we are in fact sending or receiving at the
			 moment.  That tells us who we are waiting for the
			 reply from.  */
		      if (send_port == ss->intr_port)
			{
			  /* This is a Hurd interruptible RPC.
			     Mark it by surrounding the port description
			     string with [...] brackets.  */
			  if (cur < limit)
			    *cur++ = '[';
			  cur = describe_port (cur, send_port, limit - cur);
			  if (cur < limit)
			    *cur++ = ']';
			}
		      else
			cur = describe_port (cur, send_port, limit - cur);
		    }
		  else if (rcv_port != MACH_PORT_NULL)
		    {
		      /* This system call had no send port, but had a
			 receive port.  The msgid we extracted is then just
			 some garbage or perhaps the msgid of the last
			 message this thread received, but it's not a
			 helpful thing to return.  */
		      cur = describe_port (cur, rcv_port, limit - cur);
		      cur = __stpncpy (cur, ":rcv", limit - cur);
		      *msgid = 0;
		    }
		  else if ((option & (MACH_RCV_MSG|MACH_RCV_TIMEOUT))
			   == (MACH_RCV_MSG|MACH_RCV_TIMEOUT))
		    {
		      /* A receive with no valid port can be used for a
			 pure timeout.  Report the timeout value (counted
			 in milliseconds); note this is the original total
			 time, not the time remaining.  */
		      cur = describe_number (cur, 0, timeout, limit - cur);
		      cur = __stpncpy (cur, "ms", limit - cur);
		      *msgid = 0;
		    }
		  else
		    {
		      cur = __stpncpy (cur, "mach_msg", limit - cur);
		      *msgid = 0;
		    }
		}
	      else		/* Some other system call.  */
		{
		  cur = describe_number (cur, "syscall#", *msgid, limit - cur);
		  *msgid = 0;
		}
	    }
	}
    }

  __mach_port_deallocate (__mach_task_self (), thread);

  if (cur == limit)
    return ENOMEM;

  *cur = '\0';
  return 0;
}

kern_return_t
_S_msg_describe_ports (mach_port_t msgport, mach_port_t refport,
		       mach_port_t *ports, mach_msg_type_number_t nports,
		       char **desc, mach_msg_type_number_t *desclen)
{
  char *p, *end;

  if (__USEPORT (AUTH, msgport != port))
    return EPERM;

  end = *desc + *desclen;
  p = *desc;
  while (nports-- > 0)
    {
      char this[200];
      describe_port (this, *ports++, sizeof this);
      p = __stpncpy (p, this, end - p);
      if (p == end && p[-1] != '\0')
	return ENOMEM;
    }

  *desclen = p - *desc;
  return 0;
}