线程从队列(Linux)中获取其他线程IPC消息
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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。
以下玩具程序显示了问题,可以在不同的处理器上重复进行。
任何帮助,不胜感激!
伯特
/*
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);
}
}
没有找到相关结果
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3 个回复
扦帽次杏
您很快就会发现
在这种情况下,
的回报为-1。如果两个文件都丢失,则两个ipc密钥都将为-1,这意味着所有流量共享相同的端口:) 所以
解决它。一些统计数据(用ѭ5代替睡眠):
缔恃钨
碉罕城爸
我发现由于某种原因,“ 9”失败,并且两个MQ都具有相同的ID,这是线程首先进入的竞赛。 使用此程序的修改版本,请执行以下操作:
首先创建文件。 并且您应该看到消息发送给正确的收件人。