线程从队列中获取其他线程IPC消息（Linux）

当我在Linux上有两个不同的IPC消息队列时，有时会抓取来自错误队列的消息

下面的玩具程序显示问题，可以在不同的处理器上重复

非常感谢您的帮助

伯特

/*
编辑；
gcc MM.c-o MM-fno堆栈保护器-pthread
我们想让米奇专门给米妮捎个口信。
我们想让唐纳德专门给冥王星发个信息。
问题：冥王星截获了米妮的信息。
清单给出了：
美元/毫米
米奇线程成功启动。
Minnie线程已成功启动。
冥王星线程已成功启动。
Donald线程已成功启动。
唐纳德给冥王星发了一条信息。
米奇给米妮发了条短信。
布鲁托收到：坐下，布鲁托！
米妮：你好，米妮！
米奇给米妮发了条短信。（100次）
布鲁托：你好，米妮！
*/
#包括
#包括
#包括
#包括
#包括
pthread_t t1、t2、t3、t4；
//米奇·森德
关键是米奇；
int-mqMickeyid；
char helloMickeymsg[]={“你好，米妮！”}；
结构{long type；char text[100]；}myMickeymsg；
//米妮
int mqMinnieid；
结构{long type；char text[100]；}myminniemg；
//唐纳德·森德
重点;；
int-mqDonaldid；
char helloDonaldmsg[]={“坐下，冥王星！”}；
结构{long type；char text[100]；}myDonaldmsg；
//冥王星
冥王星；
结构{long type；char text[100]；}myPlutomsg；
静态void*DONALDthreadFunc（void*arg）
{
printf（“Donald线程已成功启动。\n”）；
char*s=（char*）arg；
而(1)
{
//发送
memset（myDonaldmsg.text，01100）；
strncpy（myDonaldmsg.text、helloDonaldmsg、strlen（helloDonaldmsg））；
myDonaldmsg.type=1；
msgsnd（mqDonaldid和myDonaldmsg），sizeof（myDonaldmsg），0；
printf（“Donald向Pluto发送了一条消息。\r\n”）；
睡眠（4）；
}
/*只是一种形式*/
返回（无效*）strlen（s）；
}
静态void*PLUTOthreadFunc（void*arg）
{
printf（“Pluto线程已成功启动。\n”）；
char*s=（char*）arg；
而(1)
{
//接收
mqPlutoid=msgget（0）；
msgrcv（mqPlutoid，&myPlutomsg，sizeof（myPlutomsg），0,0）；
printf（“Pluto接收：%s\r\n\r\n”，myPlutomsg.text）；
睡眠（1）；
}
/*只是一种形式*/
返回（无效*）strlen（s）；
}
静态void*MICKEYthreadFunc（void*arg）
{
printf（“米奇线程成功启动。\n”）；
char*s=（char*）arg；
而(1)
{
//发送
memset（myMickeymsg.text，01100）；
strncpy（myMickeymsg.text、helloMickeymsg、strlen（helloMickeymsg））；
myMickeymsg.type=1；
msgsnd（mqMickeyid和myMickeymsg），sizeof（myMickeymsg），0；
printf（“Mickey向Minnie发送了一条消息。\r\n”）；
美国LEEP（10000）；
}
/*只是一种形式*/
返回（无效*）strlen（s）；
}
静态void*MINNIEthreadFunc（void*arg）
{
printf（“Minnie线程已成功启动。\n”）；
char*s=（char*）arg；
而(1)
{
//接收
mqMinnieid=msgget（ipcMickey，0）；
msgrcv（mqMinnieid，&myminniemg，sizeof（myminniemg），0,0）；
printf（“收到的Minnie:%s\r\n\r\n”，myminniemg.text）；
睡眠（3）；
}
返回（无效*）strlen（s）；
}
内部主（空）
{
ipcMickey=ftok（“/tmp/mqmickey”，63）；
mqMickeyid=msgget（ipcMickey，IPC|U CREAT | 0666）；
ipcdonard=ftok（“/tmp/mqdonald”，69）；
mqDonaldid=msgget（ipcDonald，IPC|u CREAT | 0666）；
pthread_create（&t1，NULL，MICKEYthreadFunc，“Mickey发送”\n）；
pthread_create（&t2，NULL，MINNIEthreadFunc，“Minnie回复\n”）；
pthread_create（&t3，NULL，DONALDthreadFunc，“donaldsends\n”）；
pthread_create（&t4，NULL，PLUTOthreadFunc，“Pluto回复\n”）；
而(1)
{
睡眠（5）；
}
}

问题在于您错过了错误处理

包括

ipcMickey = ftok("/tmp/mqmickey", 63);
if (-1==ipcMickey)
{
    perror("ipcMickey");
    exit(255);
}
ipcDonald = ftok("/tmp/mqdonald", 69);
if (-1==ipcDonald)
{
    perror("ipcDonald");
    exit(255);
}

你很快就会发现

./mm
ipcDonald: No such file or directory

在这种情况下，

ftok

的返回值为-1。如果两个文件都丢失，两个ipc密钥都将为-1，这意味着所有通信共享同一端口：）

所以

修复它。一些统计信息（用

usleep（random（）%10000）

替换睡眠）：

---

以下是您的程序的稍加修改的版本：

/*
    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\nPluto uses MQ with id = %d\r\n", myPlutomsg.text,mqPlutoid);
        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\nMinnie uses MQ with id = %d\r\n", myMinniemsg.text,mqMinnieid);
        sleep(3);
    }

    return (void *) strlen(s);
}

int main (void)
{
    ipcMickey = ftok("./mqmickey", 63);
    mqMickeyid = msgget(ipcMickey, IPC_CREAT | 0666);
    printf( "mqMickeyid=%d\n",mqMickeyid);

    ipcDonald = ftok("./mqdonald", 69);
    mqDonaldid = msgget(ipcDonald, IPC_CREAT | 0666);
    printf( "mqDonaldid=%d\n",mqDonaldid);

    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);
    }
}

首先创建文件

---

您应该会看到发送给正确收件人的邮件。

非常感谢sehe和VJo

这是程序的修改版本，考虑了您的所有意见

希望这对其他人有用

伯特

/*
我们想让米奇专门给米妮捎个口信。
我们想让唐纳德专门给冥王星发个信息。
汇编：
gcc mm.c-o mm-fno堆栈保护器-pthread
要求：
系统日志已启用并已启动。
要测试：
时间./mm{trap“INT；sort | uniq-c | tee stats；}
结果：
1503373唐纳德给冥王星发了一条信息。
1个线程已成功启动。
1423964米奇给米妮发了一条短信。
1米奇线程成功启动。
1423958米妮收到：你好，米妮！
1个Minnie线程已成功启动。
1503333冥王星收到：坐下，冥王星！
1个冥王星线程已成功启动。
真正的0m17.133s
用户0m16.053s
系统0m5.248s
*/
#包括
#包括
#包括
#包括
#包括
#包括
#包括
#定义MQMICKEY“/tmp/MQMICKEY”
#定义MQDONALD“/tmp/MQDONALD”
pthread_t t1、t2、t3、t4；
文件*fmickeypoter；
文件*fDonaldpointer；
//米奇·森德
关键是米奇；
int-mqMickeyid；
char helloMickeymsg[]={“你好，米妮！”}；
结构{long type；char text[100]；}myMickeymsg；
//米妮
int mqMinnieid；
结构{long type；char text[100]；}myminniemg；
//唐纳德·森德
重点;；
int-mqDonaldid；
char helloDonaldmsg[]={“坐下，冥王星！”}；
结构{long type；char text[100]；}myDonaldmsg；
//冥王星
冥王星；
结构{long type；char text[100]；}myPlu
touch /tmp/mqmickey /tmp/mqdonald

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

/*
    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\nPluto uses MQ with id = %d\r\n", myPlutomsg.text,mqPlutoid);
        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\nMinnie uses MQ with id = %d\r\n", myMinniemsg.text,mqMinnieid);
        sleep(3);
    }

    return (void *) strlen(s);
}

int main (void)
{
    ipcMickey = ftok("./mqmickey", 63);
    mqMickeyid = msgget(ipcMickey, IPC_CREAT | 0666);
    printf( "mqMickeyid=%d\n",mqMickeyid);

    ipcDonald = ftok("./mqdonald", 69);
    mqDonaldid = msgget(ipcDonald, IPC_CREAT | 0666);
    printf( "mqDonaldid=%d\n",mqDonaldid);

    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);
    }
}

touch mqmickey
touch mqdonald

/*
    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);
}