summaryrefslogtreecommitdiff
path: root/ace/SV_Semaphore_Simple.cpp
blob: f7a6809dbb2183411948dcfd6bf193605f52516c (plain)
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
// SV_Semaphore_Simple.cpp
// $Id$

/* -*- C++ -*- */

#define ACE_BUILD_DLL
#include "ace/SV_Semaphore_Simple.h"

ACE_ALLOC_HOOK_DEFINE(ACE_SV_Semaphore_Simple)

void
ACE_SV_Semaphore_Simple::dump (void) const
{
  ACE_TRACE ("ACE_SV_Semaphore_Simple::dump");
}

int
ACE_SV_Semaphore_Simple::control (int cmd, 
				  int value, 
				  u_short semnum) const
{
  ACE_TRACE ("ACE_SV_Semaphore_Simple::control");
  if (this->internal_id_ == -1)
    return -1;
  else
    {
      semun semctl_arg;

      semctl_arg.val = value;
      return ACE_OS::semctl (this->internal_id_, semnum, 
			     cmd, semctl_arg);
    }
}

int
ACE_SV_Semaphore_Simple::init (key_t k, int i)
{
  ACE_TRACE ("ACE_SV_Semaphore_Simple::init");
  this->key_ = k;
  this->internal_id_ = i;
  return 0;
}

// General ACE_SV_Semaphore operation. Increment or decrement by a
// specific amount (positive or negative; amount can`t be zero). 
     
int 
ACE_SV_Semaphore_Simple::op (int val, u_short n, int flags) const
{
  ACE_TRACE ("ACE_SV_Semaphore_Simple::op");
  sembuf op_op;

  op_op.sem_num = n;
  op_op.sem_flg = flags;

  if (this->internal_id_ == -1)
    return -1;
  else if ((op_op.sem_op = val) == 0)
    return -1;
  else
    return ACE_OS::semop (this->internal_id_, &op_op, 1);
}

// Open or create one or more SV_Semaphores.  We return 0 if all is
// OK, else -1.

int 
ACE_SV_Semaphore_Simple::open (key_t k, 
			       int flags, 
			       int initial_value, 
			       u_short n, 
			       int perms)
{
  ACE_TRACE ("ACE_SV_Semaphore_Simple::open");
  union semun ivalue;

  if (k == IPC_PRIVATE || k == ACE_INVALID_SEM_KEY)
    return -1;

  ivalue.val = initial_value;
  this->key_ = k;
  this->sem_number_ = n;

  this->internal_id_ = ACE_OS::semget (this->key_, n, perms | flags);

  if (this->internal_id_ == -1)
    return -1;

  if (flags == IPC_CREAT)
    {
      for (int i = 0; i < n; i++)
	if (ACE_OS::semctl (this->internal_id_, i, SETVAL, ivalue) == -1)
	  return -1;
    }

  return 0;
}

ACE_SV_Semaphore_Simple::ACE_SV_Semaphore_Simple (key_t k, 
						  int flags, 
						  int initial_value, 
						  u_short n, 
						  int perms)
  : key_ (k)
{
  ACE_TRACE ("ACE_SV_Semaphore_Simple::ACE_SV_Semaphore_Simple");
  if (this->open (k, flags, initial_value, n, perms) == -1)
    ACE_ERROR ((LM_ERROR, "%p\n", "ACE_SV_Semaphore::ACE_SV_Semaphore"));
}

// Convert name to key.  This function is used internally to create keys
// for the semaphores.  A valid name contains letters and digits
// only and MUST start with a letter.
//
// The method for generating names is not very sophisticated, so
// caller should not pass strings which match each other for the first
// LUSED characters when he wants to get a different key.  

key_t 
ACE_SV_Semaphore_Simple::name_2_key (const char *name)
{
  ACE_TRACE ("ACE_SV_Semaphore_Simple::name_2_key");
  
  if (name == 0)
    {
      errno = EINVAL;
      return ACE_INVALID_SEM_KEY;
    }
  else
    {
      // Basically "hash" the values in the <name>.  This won't
      // necessarily guarantee uniqueness of all keys.

      u_long proto = 0;

      for (int i = 0; name[i] != '\0'; ++i)
	{
	  proto <<= 8;
	  proto |= *name++ & 0xff;
	}

      return (key_t) proto;
    }
}

// Open or create a ACE_SV_Semaphore.  We return 1 if all is OK, else
// 0.
     
int 
ACE_SV_Semaphore_Simple::open (const char *name, 
			       int flags, 
			       int initial_value, 
			       u_short n, 
			       int perms)
{
  ACE_TRACE ("ACE_SV_Semaphore_Simple::open");

  key_t key;
  
  if (name == 0)
    key = ACE_DEFAULT_SEM_KEY;
  else 
    key = this->name_2_key (name);

  return this->open (key, flags, initial_value, n, perms);
}

ACE_SV_Semaphore_Simple::ACE_SV_Semaphore_Simple (const char *name, 
						  int flags, 
						  int initial_value, 
						  u_short n, 
						  int perms)
{
  ACE_TRACE ("ACE_SV_Semaphore_Simple::ACE_SV_Semaphore_Simple");
  if (this->open (name, flags, initial_value, n, perms) == -1)
    ACE_ERROR ((LM_ERROR, "%p\n", 
		"ACE_SV_Semaphore_Simple::ACE_SV_Semaphore_Simple"));
}

ACE_SV_Semaphore_Simple::~ACE_SV_Semaphore_Simple (void)
{
  ACE_TRACE ("ACE_SV_Semaphore_Simple::~ACE_SV_Semaphore_Simple");
  this->close ();
}

ACE_SV_Semaphore_Simple::ACE_SV_Semaphore_Simple (void)
{
  ACE_TRACE ("ACE_SV_Semaphore_Simple::ACE_SV_Semaphore_Simple");
  this->init ();
}

// Remove all SV_Semaphores associated with a particular key.  This
// call is intended to be called from a server, for example, when it
// is being shut down, as we do an IPC_RMID on the ACE_SV_Semaphore,
// regardless of whether other processes may be using it or not.  Most
// other processes should use close() below.
     
int 
ACE_SV_Semaphore_Simple::remove (void) const
{
  ACE_TRACE ("ACE_SV_Semaphore_Simple::remove");
  int result = this->control (IPC_RMID);
  ((ACE_SV_Semaphore_Simple *) this)->init ();
  return result;
}