本地套接字domain通信

client.c

#include<errno.h>#include<semaphore.h>#include<string.h>#include<sys/stat.h>#include<fcntl.h>#include<errno.h>#include<stdlib.h>#include<unistd.h>#include<stdio.h>#include<sys/mman.h>#include<sys/types.h>#include<signal.h>#include<pthread.h>#include<netinet/in.h>#include<arpa/inet.h>#include<sys/socket.h>#define SERVER_PORT 8000#define MAXLINE 4096#define QLEN 10#define CLI_PATH "/var/tmp/"int cli_conn(const char* name){    int fd,len,err,rval;    struct sockaddr_un un;    if((fd=socket(AF_UNIX,SOCK_STREAM,0))<0)return -1;    unlink(name);    bzero(&un,sizeof(un));    un.sun_family=AF_UNIX;    sprintf(un.sun_path,"%s%05d",CLI_PATH,getpid());    len=offsetof(struct sockaddr_un,sun_path)+strlen(un.sun_path);    unlink(un.sun_path);    if(bind(fd,(struct sockaddr*)&un,len)<0){        rval=-2;        goto errout;    }    if(listen(fd,QLEN)<0){        rval=-3;        goto errout;    }    return (fd);    errout:        err=errno;        close(fd);        errno=err;        return (rval);}int serv_accept(int listenfd,uid_t* uidpr){    int clifd,len,err,rval;    time_t staletime;    struct sockaddr_un un;    struct stat statbuf;    len=sizeof(un);    if((clifd=accept(listenfd,(struct sockaddr*)&un,&len))<0)return -1;    len-=offsetof(struct sockaddr_un,sun_path);    un.sun_path[len]=0;    if(stat(un.sun_path,&statbuf)<0){        rval=-2;        goto errout;    }    if(S_ISSOCK(statbuf.st_mode)==0){        rval=-3;        goto errout;    }    if(uidptr!=NULL)        *uidptr=statbuf.st_uid;    unlink(un.sun_path);    return (clifd);errout:    err=errno;    close(clifd);    errno=err;    return rval;}int main(){    char buf[1024];    int fd,n;    fd=cli_conn("foo.socket");    if(fd<0){        switch(fd){        case -4:perror("connect");break;        case -3:perror("listen");break;        case -2:perror("bind");break;        case -1:perror("socket");break;        }        exit(-1);    }    while(fgets(buf,sizeof(buf),stdin)!=NULL){        write(fd,buf,strlen(buf));        n=read(fd,buf,sizeof(buf));        write(STDOUT_FILENO,buf,n);    }    close(fd);    return 0;}

server.c

#include<errno.h>#include<semaphore.h>#include<string.h>#include<sys/stat.h>#include<fcntl.h>#include<errno.h>#include<stdlib.h>#include<unistd.h>#include<stdio.h>#include<sys/mman.h>#include<sys/types.h>#include<signal.h>#include<pthread.h>#include<netinet/in.h>#include<arpa/inet.h>#include<sys/socket.h>#define SERVER_PORT 8000#define MAXLINE 4096#define QLEN 10int serv_listen(const char* name){    int fd,len,err,rval;    struct sockaddr_un un;    if((fd=socket(AF_UNIX,SOCK_STREAM,0))<0)return -1;    unlink(name);    bzero(&un,sizeof(un));    un.sun_family=AF_UNIX;    strcpy(un.sun_path,name);    len=offsetof(struct sockaddr_un,sun_path)+strlen(name);    if(bind(fd,(struct sockaddr*)&un,len)<0){        rval=-2;        goto errout;    }    if(listen(fd,QLEN)<0){        rval=-3;        goto errout;    }    return (fd);    errout:        err=errno;        close(fd);        errno=err;        return (rval);}int serv_accept(int listenfd,uid_t* uidpr){    int clifd,len,err,rval;    time_t staletime;    struct sockaddr_un un;    struct stat statbuf;    len=sizeof(un);    if((clifd=accept(listenfd,(struct sockaddr*)&un,&len))<0)return -1;    len-=offsetof(struct sockaddr_un,sun_path);    un.sun_path[len]=0;    if(stat(un.sun_path,&statbuf)<0){        rval=-2;        goto errout;    }    if(S_ISSOCK(statbuf.st_mode)==0){        rval=-3;        goto errout;    }    if(uidptr!=NULL)        *uidptr=statbuf.st_uid;    unlink(un.sun_path);    return (clifd);errout:    err=errno;    close(clifd);    errno=err;    return rval;}int main(){    int lfd,cfd,n,i;    uid_t cuid;    char buf[1024];    lfd=serv_listen("foo.socket");    if(lfd<0){        switch(lfd){        case -3:perror("listen");break;        case -2:perror("bind");break;        case -1:perror("socket");break;        }        exit(-1);    }    cfd=serv_accept(lfd,&cuid);    if(cfd<0){        switch(cfd){            case -3:perror("not a socket");break;            case -2:perror("a bad filename");break;            case -1:perror("accept");break;        }        exit(-1);    }    while(1){r_again:        n=read(cfd,buf,1024);        if(n==-1){            if(errno==EINTR)goto r_again;        }        else if(n==0){            printf("the other side has been closed.\n");            break;        }        for(i=0;i<n;i++){            buf[i]=toupper(buf[i]);        }        write(cfd,buf,n);    }    close(fd);    close(lfd);    return 0;}