1 #include
2 #include
3 #include
4 #include //为了使用sleep()函数
5 #include
6 #include //为了产生中断
7
8 //哲学家的数目
9 int Number;
10
11 //声明共享变量fork，其中fork的数目和哲学家数目是相同的
12 struct Fork{
13 int i;//只有0和1两个值，0代表不能被拿起来，1代表可以被拿起来
14 };
15 struct Fork *myfork;
16
17 //定义一个philosopher的三个状态
18 #define Thinking 1
19 #define Trying 2
20 #define Eating 3
21
22 struct State{
23 int sta;
24 int left;
25 int right;
26 };
27 struct State *state;
28
29 void *EatMeal();
30
31
32 int totalnumber;
33 void DetectLock(int);
34 void Sig_hander(int);
35
36 //得到参数
37 void GetArg(
38 char* argv[] /*in*/,
39 int* number /*out*/
40 );
41 //统计处于tring状态的哲学家的个数
42 int tryingNo;
43
44 //拿起叉子
45 int take_Fork(int i);
46 //放下叉子
47 void put_Fork(int i);
48
49 void main(int argc, char* argv[])
50 {
51 GetArg(argv, &Number);
52 myfork = (struct Fork *)malloc(Number*sizeof(struct Fork));
53 state = malloc(Number*sizeof(struct State));
54
55 tryingNo = 0;
56 //声明进程数组，每一个进程代表一个哲学家
57 pthread_t philosopher[Number];
58 pthread_t deadLockDetecter;
59 totalnumber = Number;
60 /*初始化每个哲学家的状态*/
61 int t =0;
62 for(t=0; t)
63 {
64 state[t].sta = Thinking;
65 state[t].left = 0;
66 state[t].right = 0;
67 }
68
69 /*初始化每个勺子是可以使用的*/
70 int k =0;
71 for(k=0; k)
72 {
73 myfork[k].i = 1;
74 }
75
76 int i;
77 //创建和哲学家数量想对应的进程，并且每个进程开始进行吃饭的活动
78 for( i = 0; i )
79 {
80 //记录当前进程的编号，并传递到Meal()函数中
81 int j = i;
82 pthread_create(&philosopher[i], NULL, EatMeal, &j);
83 printf("I am philosopher %d\n", j);
84 }
85
86 //int k = Number;
87 pthread_create(&deadLockDetecter,NULL, DetectLock,&k);
88
89 //将所有的进程进行Join操作。
90 for( i=0; i )
91 {
92 pthread_join(philosopher[i], NULL);
93 }
94
95 //退出程序
96 pthread_exit(0);
97
98 return ;
99
100 }
101
102 void *EatMeal(int *i)
103 {
104 //记录当前的线程id号
105 int id = *i;
106
107
108 state[id].sta = Thinking; //线程初始化的时候为Thinking
109
110 int leftFork = (id + Number) % Number;
111 int rightFork = (id + Number +1) % Number;
112
113 int mealTime = 5;
114 int mymealTime = 0;
115 while (mymealTime //每个philosopher必须吃得符合规定
116 {
117 if(state[id].sta == Thinking)
118 {
119 sleep(3);
120 state[id].sta = Trying;
121 }else if(state[id].sta == Trying)
122 {
123
124 // sleep(1);
125 if (take_Fork(leftFork))
126 {
127 myfork[leftFork].i = 0;
128 state[id].left = 1; //自己标识左边的叉子被自己拿到
129 // printf("Phi %d takes left\n",id);
130 }
131 if(take_Fork(rightFork))
132 {
133 myfork[rightFork].i = 0;
134 state[id].right = 1; //自己标识一下右边的叉子被自己拿到
135 // printf("Phi %d takes right\n",id);
136 }
137
138 printf("Philosopher %d is Trying\n", id);
139 sleep(3);
140 if(!take_Fork(leftFork)&&!take_Fork(rightFork)&&state[id].left==1&& state[id].right==1)
141 {
142 state[id].sta = Eating;
143 }
144 }
145 else
146 {
147 printf("Philosopher %d is Eating\n", id);
148 sleep(3);
149 state[id].left=0;
150 state[id].right=0;
151 state[id].sta = Thinking;
152 put_Fork(leftFork);
153 put_Fork(rightFork);
154 mymealTime++;
155
156 }
157 }
158
159 }
160
161 int take_Fork(int forkid)
162 {
163 if(myfork[forkid].i==0) return 0;
164 else
165 {
166 //myfork[forkid].i = 0;
167 return 1;
168 }
169 }
170
171 void put_Fork(int forkid)
172 {
173 if(myfork[forkid].i==0)
174 {
175 myfork[forkid].i=1;
176 }
177 }
178
179 void GetArg(
180 char * argv[],
181 int* number
182 )
183 {
184 *number = strtol(argv[1], NULL, 10);
185 }
186
187 void DetectLock(
188 int k)
189 {
190 signal(SIGALRM, Sig_hander);
191 alarm(1);
192 while(1) pause();
193 }
194
195 void Sig_hander(int sig)
196 {
197 int k = totalnumber;//获取人数
198 int flag = 1;
199 int i = 0;
200 for(i=0; i)
201 {
202 if(state[i].sta != Trying)
203 {
204 flag = 0;
205 }
206 }
207 if(flag == 1)
208 {
209 printf("I am timer that dealing with deadlock\n");
210 int m = 0;
211 for(m=0; m)
212 {
213 state[m].sta = Thinking;
214 state[m].left = 0;
215 state[m].right = 0;
216 myfork[m].i = 1;
217 }
218 }
219
220
221 alarm(1);
222 return;
223
224
225 }
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