Esempi di server con le message queue

[gapil.git] / sources / MQFortuneServer.c

diff --git a/sources/MQFortuneServer.c b/sources/MQFortuneServer.c
index e1319782e8da9f65141842c836c0b3655b865cbf..4d4ec74944d1965a6f05106f87e1c9d93e8ee1e3 100644 (file)
--- a/sources/MQFortuneServer.c
+++ b/sources/MQFortuneServer.c
@@ -19,14 +19,14 @@
 /****************************************************************
  *
  * Program fortuned 
- * Fortune server - Using Messag queues
+ * Fortune server - Using Message Queues
  *
  * Author: Simone Piccardi
  * Aug. 2002
  *
  * Usage: fortuned -h give all info
  *
- * $Id: MQFortuneServer.c,v 1.1 2002/08/26 21:11:49 piccardi Exp $
+ * $Id: MQFortuneServer.c,v 1.2 2002/10/20 22:40:34 piccardi Exp $
  *
  ****************************************************************/
 /* 
@@ -40,33 +40,37 @@
 #include <string.h>     /* ANSI C standard string */
 #include <errno.h>      /* errorstring */
 #include <signal.h>     /* signals */
-#include <fcntl.h>      /*  */
+#include <sys/ipc.h>
+#include <sys/msg.h>
 
 #include "macros.h"
 #include "wrappers.h"
 
+/* Maximum message size */
+#define MSGMAX 8192
+
 /* Subroutines declaration */
 void usage(void);
 void HandSIGTERM(int signo);
 int FortuneParse(char *file, char **fortune, int n);
 
-/* name of well known fifo */
+int msgid;                                       /* Message queue identifier */
 int main(int argc, char *argv[])
 {
 /* Variables definition */
     int i, n = 0;
-    char **fortune;
-    struct msgbuf_read {
-       long mtype;      /* message type, must be > 0 */
-       int pid;         /* message data */
+    char **fortune;                       /* array of fortune message string */
+    char *fortunefilename;                              /* fortune file name */
+    struct msgbuf_read {      /* message struct to read request from clients */
+       long mtype;                               /* message type, must be 1 */
+       long pid;             /* message data, must be the pid of the client */
     } msg_read;
-    struct msgbuf_write {
-       long mtype;      /* message type, must be > 0 */
-       char mtext[MSGMAX];  /* message data */
+    struct msgbuf_write {       /* message struct to write result to clients */
+       long mtype;            /* message type, will be the pid of the client*/
+       char mtext[MSGMAX];             /* message data, will be the fortune */
     } msg_write;
-    int msgid;
-    key_t key;
-    int size;
+    key_t key;                                          /* Message queue key */
+    int size;                                                /* message size */
     /*
      * Input section: decode parameters passed in the calling 
      * Use getopt function
@@ -77,20 +81,19 @@ int main(int argc, char *argv[])
        /* 
         * Handling options 
         */ 
-       case 'h':  
-           printf("Wrong -h option use\n");
+       case 'h':                                       /* print usage infos */
            usage();
            return(0);
            break;
-       case 'f':
+       case 'f':                                   /* set fortune file name */
            fortunefilename = optarg;
            break;
-       case 'n':
+       case 'n':                     /* set number of fortune string to use */
            n = strtol(optarg, NULL, 10);
            fortune = (char **) calloc(sizeof(*fortune), n);
            break;
        case '?':                                    /* unrecognized options */
-           printf("Unrecognized options -%c\n",optopt);
+           printf("Unrecognized options -%c\n", optopt);
            usage();
        default:                                       /* should not reached */
            usage();
@@ -113,15 +116,21 @@ int main(int argc, char *argv[])
      * Comunication section 
      */
     key = ftok("./MQFortuneServer.c", 1); 
-    msgid = msgget(key, IPC_CREAT|666); 
-    
+    msgid = msgget(key, IPC_CREAT|0666);
+    if (msgid < 0) {
+       perror("Cannot create message queue");
+       exit(1);
+    }
+
     /* Main body: loop over requests */
     while (1) {
-       msgrcv(msgid, &msg_read, 1, sizeof(int), MSG_NOERROR);
+       msgrcv(msgid, &msg_read, sizeof(int), 1, MSG_NOERROR);
+       debug("received request from %d\n", msg_read.pid);
        n = random() % i;                             /* select random value */
-       strncpy(msgbuf_write.mtext, fortune[n], MSGMAX);
+       strncpy(msg_write.mtext, fortune[n], MSGMAX);
        size = min(strlen(fortune[n])+1, MSGMAX);  
-       msgsnd(msgid,  &msg_write, size, 0);
+       msg_write.mtype=msg_read.pid;             /* use request pid as type */
+       msgsnd(msgid, &msg_write, size, 0);
     }
     debug("Exiting for unknown reasons\n");
 }
@@ -134,7 +143,7 @@ void usage(void) {
     printf("  fortuned [-h] [-f] -n XXX \n");
     printf("  -h   print this help\n");
     printf("  -f filename   set file for fortunes\n");
-    printf("  -n XXX        set pool depth\n");
+    printf("  -n NNN        set pool depth\n");
     exit(1);
 }
 /*
@@ -142,6 +151,6 @@ void usage(void) {
  */
 void HandSIGTERM(int signo) {
     debug("Terminated by %s\n", strsignal(signo));
-    unlink(fifoname);
+    msgctl(msgid, IPC_RMID, NULL);                   /* remove message queue */
     exit(0);
 }