Linuxシステムプログラミング:クライアント-サーバがFIFOで通信する

1 struct CLIENTINFO{

2     char myfifo[500];

3     int leftarg;

4     int rightarg;

5     char op;

6 }; 

7 typedef struct CLIENTINFO CLIENTINFO, *CLINTINFOPTR;

 1 #include <unistd.h>

 2 #include <stdio.h>

 3 #include <stdlib.h>

 4 #include <string.h>

 5 #include <sys/types.h>

 6 #include <fcntl.h>

 7 #include <signal.h>

 8 #include "clientinfo.h"

 9 

10 #define FIFO_NAME "/home/levi/chatapplication/data/server_fifo/chat_server_fifo"

11 #define BUFF_SZ 100

12 

13 char mypipename[BUFF_SZ];

14 void handler(int sig){

15     unlink(mypipename);

16     exit(1);

17 }

18 

19 int main(int argc, char const *argv[])

20 {

21     int res;

22     int fifo_fd, my_fifo;

23     int fd;

24     CLIENTINFO info;

25     char buffer[BUFF_SZ];

26 

27     signal(SIGKILL, handler);

28     signal(SIGINT, handler);

29     signal(SIGTERM, handler);

30 

31     if(argc != 4){

32         printf("Usage: %s op1 operation op2
", argv[0]);

33         exit(1);

34     }

35     if(access(FIFO_NAME, F_OK) == -1){

36         printf("Could not open FIFO %s
", FIFO_NAME);

37         exit(EXIT_FAILURE);

38     }

39     fifo_fd = open(FIFO_NAME, O_WRONLY);

40     if(fifo_fd == -1){

41         printf("Could not open %s for write access
", FIFO_NAME);

42         exit(EXIT_FAILURE);

43     }

44     sprintf(mypipename, "/home/levi/chat_client_%d_fifo", getpid());

45     res = mkfifo(mypipename, 0777);

46     if(res != 0){

47         printf("FIFO %s was not created
", buffer);

48         exit(EXIT_FAILURE);

49     }

50 

51     my_fifo = open(mypipename, O_RDONLY | O_NONBLOCK);

52     if(my_fifo == -1){

53         printf("Could not open %s for read only access
", FIFO_NAME);

54         exit(EXIT_FAILURE);

55     }

56 

57     strcpy(info.myfifo, mypipename);

58     info.leftarg = atoi(argv[1]);

59     info.op = argv[2][0];

60     info.rightarg = atoi(argv[3]);

61 

62     write(fifo_fd, &info, sizeof(CLIENTINFO));

63     close(fifo_fd);

64 

65     memset(buffer, '\0', BUFF_SZ);

66     while(1){

67         res = read(my_fifo, buffer, BUFF_SZ);

68         if(res > 0){

69             printf("Received from server : %s
", buffer);

70             break;

71         }

72     }

73     printf("Client %d is terminating
", getpid());

74     close(my_fifo);

75     (void)unlink(mypipename);

76     return 0;

77 }

 1 #include <unistd.h>

 2 #include <stdio.h>

 3 #include <stdlib.h>

 4 #include <string.h>

 5 #include <sys/types.h>

 6 #include <fcntl.h>

 7 #include <signal.h>

 8 #include "clientinfo.h"

 9 

10 #define FIFO_NAME "/home/levi/server_fifo/chat_server_fifo"

11 void handler(int sig){

12     unlink(FIFO_NAME);

13     exit(1);

14 }

15 

16 int calc(CLIENTINFOPTR info){

17     switch(info->op){

18         case '+' : return info->leftarg + info->rightarg;

19         case '-' : return info->leftarg - info->rightarg;

20         case '*' : return info->leftarg * info->rightarg;

21         case '/' : return info->leftarg / info->rightarg;

22     }

23     return 0;

24 }

25 

26 int main(int argc, char const *argv[])

27 {

28     int res, i, fifo_fd, fd1;

29     CLIENTINFO info;

30     char buffer[100];

31     signal(SIGKILL, handler);

32     signal(SIGINT, handler);

33     signal(SIGTERM, handler);

34     if(access(FIFO_NAME, F_OK) == -1){

35         res = mkfifo(FIFO_NAME, 0777);

36         if(res != 0){

37             printf("FIFO %s was not created
", FIFO_NAME);

38             exit(EXIT_FAILURE);

39         }

40     }

41     fifo_fd = open(FIFO_NAME, O_RDONLY);

42     if(fifo_fd == -1){

43         printf("Could not open %s for read only access
", FIFO_NAME);

44         exit(EXIT_FAILURE);

45     }

46     printf("
Server is rarin to go !
");

47     while(1){

48         res = read(fifo_fd, &info, sizeof(CLIENTINFO));

49         if(res != 0){

50             printf("Client arrived!!
");

51             sprintf(buffer, "The result is %d", calc(&info));

52             fd1 = open(info.myfifo, O_WRONLY | O_NONBLOCK);

53             write (fd1, buffer, strlen(buffer) + 1);

54             close(fd1);

55         }

56 

57     }

58     return 0;

59 }