Lorsque j'ai deux files d'attente de message IPC différentes sur Linux, les messages de la mauvaise file d'attente sont saisis.
Le programme de jouet suivant affiche le problème, peut être répété sur différents processeurs. P>
Toute aide grandement appréciée! p>
Bert p>
/* To compile; gcc MM.c -o mm -fno-stack-protector -pthread We want Mickey to send a message to Minnie exclusively. We want Donald to send a message to pluto exclusively. Problem: Pluto intercepts Minnie's messages. Listing gives: $ ./mm Mickey thread successfully started. Minnie thread successfully started. Pluto thread successfully started. Donald thread successfully started. Donald sent a message to Pluto. Mickey sent a message to Minnie. Pluto received: Sit, Pluto! Minnie received: Hello, Minnie! Mickey sent a message to Minnie. (100 times) Pluto received: Hello, Minnie! */ #include <sys/types.h> #include <sys/msg.h> #include <sys/ipc.h> #include <string.h> #include <stdio.h> pthread_t t1,t2,t3,t4; // Mickey send key_t ipcMickey; int mqMickeyid; char helloMickeymsg[] = {"Hello, Minnie!"}; struct { long type; char text[100]; } myMickeymsg; // Minnie get int mqMinnieid; struct { long type; char text[100]; } myMinniemsg; // Donald send key_t ipcDonald; int mqDonaldid; char helloDonaldmsg[] = {"Sit, Pluto!"}; struct { long type; char text[100]; } myDonaldmsg; // Pluto get int mqPlutoid; struct { long type; char text[100]; } myPlutomsg; static void * DONALDthreadFunc(void *arg) { printf("Donald thread successfully started.\n"); char *s = (char *) arg; while(1) { //send memset(myDonaldmsg.text, 0, 100); strncpy(myDonaldmsg.text, helloDonaldmsg, strlen(helloDonaldmsg)); myDonaldmsg.type = 1; msgsnd(mqDonaldid, &myDonaldmsg, sizeof(myDonaldmsg), 0); printf("Donald sent a message to Pluto.\r\n"); sleep(4); } /* just a formality */ return (void *) strlen(s); } static void * PLUTOthreadFunc(void *arg) { printf("Pluto thread successfully started.\n"); char *s = (char *) arg; while(1) { //receive mqPlutoid = msgget(ipcDonald, 0); msgrcv(mqPlutoid, &myPlutomsg, sizeof(myPlutomsg), 0, 0); printf("Pluto received: %s\r\n\r\n", myPlutomsg.text); sleep(1); } /* just a formality */ return (void *) strlen(s); } static void * MICKEYthreadFunc(void *arg) { printf("Mickey thread successfully started.\n"); char *s = (char *) arg; while(1) { //send memset(myMickeymsg.text, 0, 100); strncpy(myMickeymsg.text, helloMickeymsg, strlen(helloMickeymsg)); myMickeymsg.type = 1; msgsnd(mqMickeyid, &myMickeymsg, sizeof(myMickeymsg), 0); printf("Mickey sent a message to Minnie.\r\n"); usleep(10000); } /* just a formality */ return (void *) strlen(s); } static void * MINNIEthreadFunc(void *arg) { printf("Minnie thread successfully started.\n"); char *s = (char *) arg; while(1) { //receive mqMinnieid = msgget(ipcMickey, 0); msgrcv(mqMinnieid, &myMinniemsg, sizeof(myMinniemsg), 0, 0); printf("Minnie received: %s\r\n\r\n", myMinniemsg.text); sleep(3); } return (void *) strlen(s); } int main (void) { ipcMickey = ftok("/tmp/mqmickey", 63); mqMickeyid = msgget(ipcMickey, IPC_CREAT | 0666); ipcDonald = ftok("/tmp/mqdonald", 69); mqDonaldid = msgget(ipcDonald, IPC_CREAT | 0666); pthread_create(&t1, NULL, MICKEYthreadFunc, "Mickey sends\n"); pthread_create(&t2, NULL, MINNIEthreadFunc, "Minnie replies\n"); pthread_create(&t3, NULL, DONALDthreadFunc, "Donald sends\n"); pthread_create(&t4, NULL, PLUTOthreadFunc, "Pluto replies\n"); while(1) { sleep(5); } }
3 Réponses :
Le problème est que vous avez manqué la manipulation des erreurs.
Inclure p> et vous trouverez bientôt P> gcc MM.c -o mm -O3 -fno-stack-protector -pthread
time ./mm | { trap "" INT; sort | uniq -c | tee stats; }
16047
1 Donald sent a
8054 Donald sent a message to Pluto.
1 Donald thread successfully started.
8040 Mickey sent a message to Minnie.
1 Mickey thread successfully started.
8065 Minnie received: Hello, Minnie!
1 Minnie thread successfully started.
7982 Pluto received: Sit, Pluto!
1 Pluto thread successfully started.
real 0m40.814s
user 0m0.168s
sys 0m0.092s
Il est également improbable mais loin dans le domaine de la possibilité que ftok code> renvoie la même clé pour les deux noms de fichiers. Il a simplement trop peu de bits pour éviter des collusions occasionnelles. OP devrait envisager de regarder dans les files d'attente de message POSIX (
MQ _ * CODE>), qui manque cette faille fondamentale. Vous pouvez également vous mettre en boucle de créer des fichiers temporaires jusqu'à obtenir des touches uniques, puis partagez les touches avec tous les threads / processus qui en ont besoin, plutôt que d'appeler
ftok code>.
Voici une version légèrement modifiée de votre programme:
touch mqmickey touch mqdonald
Merci beaucoup SEHE et VJO,
Voici une version modifiée du programme, en tenant compte de tous vos commentaires. P>
J'espère que cela sera utile pour quelqu'un d'autre. P >
Bert p>
/* We want Mickey to send a message to Minnie exclusively. We want Donald to send a message to pluto exclusively. To compile: gcc mm.c -o mm -fno-stack-protector -pthread Requires: syslog enabled and started. To test: time ./mm | { trap "" INT; sort | uniq -c | tee stats; } Results: 1503373 Donald sent a message to Pluto. 1 Donald thread successfully started. 1423964 Mickey sent a message to Minnie. 1 Mickey thread successfully started. 1423958 Minnie received: Hello, Minnie! 1 Minnie thread successfully started. 1503333 Pluto received: Sit, Pluto! 1 Pluto thread successfully started. real 0m17.133s user 0m16.053s sys 0m5.248s */ #include <sys/types.h> #include <sys/msg.h> #include <sys/ipc.h> #include <string.h> #include <stdio.h> #include <stdlib.h> #include <syslog.h> #define MQMICKEY "/tmp/MQMickey" #define MQDONALD "/tmp/MQDonald" pthread_t t1,t2,t3,t4; FILE *fMickeypointer; FILE *fDonaldpointer; // Mickey send key_t ipcMickey; int mqMickeyid; char helloMickeymsg[] = {"Hello, Minnie!"}; struct { long type; char text[100]; } myMickeymsg; // Minnie get int mqMinnieid; struct { long type; char text[100]; } myMinniemsg; // Donald send key_t ipcDonald; int mqDonaldid; char helloDonaldmsg[] = {"Sit, Pluto!"}; struct { long type; char text[100]; } myDonaldmsg; // Pluto get int mqPlutoid; struct { long type; char text[100]; } myPlutomsg; static void * DONALDthreadFunc(void *arg) { printf("Donald thread successfully started.\n"); char *s = (char *) arg; while(1) { //send memset(myDonaldmsg.text, 0, 100); strncpy(myDonaldmsg.text, helloDonaldmsg, strlen(helloDonaldmsg)); myDonaldmsg.type = 1; msgsnd(mqDonaldid, &myDonaldmsg, sizeof(myDonaldmsg), 0); printf("Donald sent a message to Pluto.\r\n"); } /* just a formality */ return (void *) strlen(s); } static void * PLUTOthreadFunc(void *arg) { printf("Pluto thread successfully started.\n"); char *s = (char *) arg; while(1) { //receive mqPlutoid = msgget(ipcDonald, 0); msgrcv(mqPlutoid, &myPlutomsg, sizeof(myPlutomsg), 0, 0); printf("Pluto received: %s\r\n", myPlutomsg.text); } /* just a formality */ return (void *) strlen(s); } static void * MICKEYthreadFunc(void *arg) { printf("Mickey thread successfully started.\n"); char *s = (char *) arg; while(1) { //send memset(myMickeymsg.text, 0, 100); strncpy(myMickeymsg.text, helloMickeymsg, strlen(helloMickeymsg)); myMickeymsg.type = 1; msgsnd(mqMickeyid, &myMickeymsg, sizeof(myMickeymsg), 0); printf("Mickey sent a message to Minnie.\r\n"); } /* just a formality */ return (void *) strlen(s); } static void * MINNIEthreadFunc(void *arg) { printf("Minnie thread successfully started.\n"); char *s = (char *) arg; while(1) { //receive mqMinnieid = msgget(ipcMickey, 0); msgrcv(mqMinnieid, &myMinniemsg, sizeof(myMinniemsg), 0, 0); printf(" Minnie received: %s\r\n", myMinniemsg.text); } return (void *) strlen(s); } int main (void) { /* MUST create the target files first. The return of ftok is -1 if file is missing. If BOTH files are missing, both ipc keys will be -1, meaning all traffic shares the same port. Result: one queue will acquire messages not intended for it! */ fMickeypointer = fopen(MQMICKEY, "a"); if(fMickeypointer == NULL) { printf("Failed to create Mickey queue file.\n"); /* system logging */ setlogmask (LOG_UPTO (LOG_NOTICE)); openlog ("MickeyDonald", LOG_CONS | LOG_PID | LOG_NDELAY, LOG_LOCAL1); syslog (LOG_NOTICE, "Failed to create Mickey queue file." ); closelog (); exit(91); } fDonaldpointer = fopen(MQDONALD, "a"); if(fDonaldpointer == NULL) { printf("Failed to create Donald queue file.\r\n"); /* system logging */ setlogmask (LOG_UPTO (LOG_NOTICE)); openlog ("MickeyDonald", LOG_CONS | LOG_PID | LOG_NDELAY, LOG_LOCAL1); syslog (LOG_NOTICE, "Failed to create Donald queue file." ); closelog (); exit(92); } ipcMickey = 0; ipcDonald = 0; /* make sure we assign DIFFERENT ipc values */ while(ipcMickey == ipcDonald) { ipcMickey = ftok(MQMICKEY, 63); if (-1==ipcMickey) { printf("ipcMickey does not exist.\r\n"); /* system logging */ setlogmask (LOG_UPTO (LOG_NOTICE)); openlog ("MickeyDonald", LOG_CONS | LOG_PID | LOG_NDELAY, LOG_LOCAL1); syslog (LOG_NOTICE, "Failed to ftok Mickey file." ); closelog (); exit(93); } ipcDonald = ftok(MQDONALD, 69); if (-1==ipcDonald) { printf("ipcDonald does not exist.\r\n"); /* system logging */ setlogmask (LOG_UPTO (LOG_NOTICE)); openlog ("MickeyDonald", LOG_CONS | LOG_PID | LOG_NDELAY, LOG_LOCAL1); syslog (LOG_NOTICE, "Failed to ftok Donald file." ); closelog (); exit(94); } } mqMickeyid = msgget(ipcMickey, IPC_CREAT | 0666); mqDonaldid = msgget(ipcDonald, IPC_CREAT | 0666); pthread_create(&t1, NULL, MICKEYthreadFunc, "Mickey sends\n"); pthread_create(&t2, NULL, MINNIEthreadFunc, "Minnie replies\n"); pthread_create(&t3, NULL, DONALDthreadFunc, "Donald sends\n"); pthread_create(&t4, NULL, PLUTOthreadFunc, "Pluto replies\n"); long exitcounter = 0; while(exitcounter < 100000) { exitcounter +=1; usleep(100); } exit(0); }
+1 pour la compilation d'un exemple minimal, testera