不終止的進程

Question

在我的客戶端 - 服務器應用程序中發生了一些奇怪的事情。請看看這些簡單的叉的客戶機/服務器： 客戶：

#include <sys/types.h> 
#include <sys/socket.h> 
#include <stdio.h> 
#include <stdlib.h> 
#include <unistd.h> 
#include <errno.h> 
#include <time.h> 
#include <arpa/inet.h> 
#include <string.h> 
#include <sys/stat.h> 
#include <fcntl.h> 
#include <sys/ioctl.h> 
#include <sys/time.h> 
#include <errno.h> 
#include <sys/time.h> 
#include <sys/wait.h> 


#define IP_SERVER "192.168.1.89" 
#define PORT_SERVER 65000 
#define BUFFERSIZE 1024 
#define NUMFILES 3 


double timeElapsed(struct timeval* before, struct timeval* after) { 

    return after->tv_sec - before->tv_sec + (double) (after->tv_usec - before->tv_usec)/1000000; 
} 


void getFile(char *request, struct sockaddr_in server) { 

    char buffer[1024]; 
    int sockProc, res; 
    int file; 
    int sizeServ = sizeof(server); 
    int writeFile; 

    sockProc = socket(AF_INET, SOCK_STREAM, 0); 

    if (sockProc < 0) { 
     printf("Error on creating socket client\n"); 
     perror(""); 
     exit(1); 
    } 

    file = open(request, O_CREAT | O_WRONLY, S_IRWXU); 


    res = connect(sockProc, (struct sockaddr*)&server, (socklen_t)sizeServ); 
    if (res < 0) { 
     printf("Error on connecting to server!\n"); 
     perror(""); 
     exit(1); 
    } 

    res = send(sockProc, (void*)request, strlen(request), 0); 

    memset(buffer, 0, sizeof(buffer)); 

    while((res = recv(sockProc, (void*)buffer, sizeof(buffer), 0)) > 0) { 
     write(file, (void*)buffer, strlen(buffer)); 
     memset(buffer, 0, sizeof(buffer)); 
    } 


    close(sockProc); 
    close(file); 
    return; 

    } 


    int main(int argc, char** argv) { 

    int sockCli, res, i; 

    struct sockaddr_in server; 
    int sizeServ = sizeof(server); 
    memset(&server, 0, sizeof(server)); 
    server.sin_family = AF_INET; 
    inet_pton(AF_INET, IP_SERVER, &server.sin_addr); 
    server.sin_port = htons(PORT_SERVER); 

    char files[NUMFILES][32]; 
    char nameFile[32]; 

    char command[32] = "rm *.txt"; 

    system(command); 

    struct timeval begin; 
    struct timeval end; 

    pid_t processes[NUMFILES]; 



    for(i = 0; i<NUMFILES; i++) { 

     memset(nameFile, 0, sizeof(nameFile)); 
     printf("Inserisci nome file (con estensione) da ricevere:\n"); 
     scanf("%s", nameFile); 
     strcpy(files[i], nameFile); 

    } 


    gettimeofday(&begin, NULL); 

    for(i=0; i<NUMFILES; i++) { 

     pid_t child = fork(); 

     if(child == 0) { 
      getFile(files[i], server); 
      exit(0); 
     } 

     else { 
      processes[i] = child; 
      continue; 
     } 

    } 


    /*for(i=0; i<NUMFILES; i++) { 
     waitpid(processes[i], NULL, 0); 
    }*/ 

    wait(NULL); 

    gettimeofday(&end, NULL); 
    printf("Time elapsed on TCP is %f seconds\n", timeElapsed(&begin, &end)); 
    return 0; 

    } 

和服務器：

#include <sys/socket.h> 
#include <stdio.h> 
#include <stdlib.h> 
#include <unistd.h> 
#include <errno.h> 
#include <time.h> 
#include <arpa/inet.h> 
#include <string.h> 
#include <sys/stat.h> 
#include <fcntl.h> 
#include <sys/ioctl.h> 
#include <sys/stat.h> 

#define IP_SERVER "192.168.1.89" 
#define PORT_SERVER 65000 
#define BUFFERSIZE 1024 

void execRequest(int* sockCli, struct sockaddr_in* client) { 

    char buffer[BUFFERSIZE]; 
    char request[BUFFERSIZE]; 
    int res; 

    memset(request, 0, sizeof(request)); 

    res = recv(*sockCli, (void*)request, sizeof(request), 0); 

    if(res < 0) { 
     printf("Error on recv()\n"); 
     perror(""); 
     exit(1); 
    } 
    printf("Requested file %s\n", request); 

    char resource[32] = "files/"; 
    strcat(resource, request); 

    int file = open(resource, O_RDONLY); 

    if (file < 0) { 
     printf("File %s does not exist\n", request); 
     exit(1); 
    } 

    memset(buffer, 0, sizeof(buffer)); 

    while((res = read(file, (void*)buffer, sizeof(buffer))) > 0) { 
     send(*sockCli, (void*)buffer, strlen(buffer), 0); 
     memset(buffer, 0, sizeof(buffer)); 
    } 

    close((*sockCli)); 
    close(file); 
    free(sockCli); 
    free(client); 

    return; 

    } 

int main(int argc, char** argv) { 

    int sockServ, i, res; 
    int *sockCli; 

    struct sockaddr_in server; 
    struct sockaddr_in* client; 


    sockServ = socket(AF_INET, SOCK_STREAM, 0); 

    if(sockServ < 0) { 
     printf("Error in creating socket\n"); 
     perror(""); 
     exit(1); 
    } 

    memset(&server, 0, sizeof(server)); 
    server.sin_addr.s_addr = inet_addr(IP_SERVER); 
    server.sin_port = htons(PORT_SERVER); 
    server.sin_family = AF_INET; 

    int reuse = 1; 
    res = setsockopt(sockServ, SOL_SOCKET, SO_REUSEADDR, &reuse, sizeof(int)); 
    if (res < 0) { 
     printf("setsockopt() REUSEADDR failed\n"); 
     perror(""); 
     exit(1); 
    } 

    res = bind(sockServ, (struct sockaddr*)&server, sizeof(server)); 
    if (res < 0) { 
     printf("Error on bindind TCP server!\n"); 
     perror(""); 
     exit(1); 
    } 

    res = listen(sockServ, 5); 
    if (res < 0) { 
     printf("Error on listening TCP server!\n"); 
     perror(""); 
     exit(1); 
    } 

    while(1) { 

     sockCli = (int*)malloc(sizeof(int)); 
     client = (struct sockaddr_in*)malloc(sizeof(struct sockaddr_in)); 
     int sizeClient = sizeof(struct sockaddr_in); 

     *sockCli = accept(sockServ, (struct sockaddr*)client, &sizeClient); 

     if ((*sockCli) < 0) { 
       printf("accept() failed\n"); 
     perror(""); 
     continue; 
     } 

     printf("Connected to %s:%d\n", inet_ntoa(client->sin_addr), client->sin_port); 

     if(!fork()) { 

      execRequest(sockCli, client); 
      exit(0); 

     } 

     else 
      continue; 



} 

    return 0; 


    } 

這是很奇怪的。即使服務器關閉套接字，客戶端創建的進程也不會終止，因此recv（）應返回0並讓客戶端進程退出循環。此外，讀取文件有些奇怪： 服務器只是讀取files.txt文件，但是在讀取文件時包含字符串「.txt」，並將所有這些混合文件發送給客戶端...爲什麼？ 它們就像 aaaaaaaaaaaaaaaaaa aaaaaaaaaaaaaaaaaa

但服務器簡單的文件單字符讀取和發送：

aaaaaaaaaaaaaaaaaa.txt aaaaaaaaaaaaaaaaaa

我可以解決這一切？

Answer 1

您不能使用strlen(buffer)，僅僅因爲您正在從文本文件加載字符並不意味着buffer將是一個有效的字符串，除非您採取措施確保它是。你不知道;由於您可以使用文件中的所有數據填充buffer，因此不會終止。

Answer 2

在堆棧溢出時，我們必須在這裏播放損壞的記錄多少次？ Don't cast malloc！

我粉筆這個錯誤讀取故障手冊中的，找出什麼頭包括，一個字符串是什麼（因此什麼的strlen/strcat的/ STR * {任何} *期待其輸入，printf期望的對應於%s格式說明符的參數等）和什麼是read/recv產生。

res = recv(*sockCli, (void*)request, sizeof(request), 0); 
if(res < 0) { 
    printf("Error on recv()\n"); 
    perror(""); 
    exit(1); 
} 
printf("Requested file %.*s\n", res, request); // NOTE the field width provided by 'res' 

通過手動，實例如res = read(file, (void*)buffer, sizeof(buffer))理應存儲任一錯誤或長度。該條件確保send代碼僅在長度爲值時纔會執行，那麼爲什麼不將它作爲一個使用呢？ send(*sockCli, (void*)buffer, res, 0);？

這些問題的存在似乎表明你的學習方法不起作用。你在讀哪本書？沒有書的情況下學習C有點像學習沒有交流的情況下哪些漿果是有毒的。