LINUX下的一个多线程的服务器和客户端的网络传输程序

/* These functions are belonged to a libray which can be used to transfer file simplely. Copyright (C) 1994-1995, Li Suke, School of Software,Peking University This is free software; you can redistribute it and/or modify it freely. This software is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. */ #include <sys/types.h> #include <stdio.h> #include <unistd.h> #include <sys/stat.h> #include <fcntl.h> #include <string.h> #include "rw.h" /*** * len: store the total receving data byte number * */ ssize_t readall(int fd, void* buf,size_t *len){ size_t nleft; ssize_t nread; ssize_t total; char *ptr; ptr = buf; nleft = *len; total = 0; while( nleft > 0){ if((nread = read(fd,ptr,*len)) == -1){ perror("readall"); break; } if(nread ==0) break; nleft -= nread; ptr += nread; total += nread; *len = nleft; } *len = total; return (nread==-1)?-1:0; } /*** * len: store the total sending data byte number * */ ssize_t writeall(int fd, void* buf,size_t *len){ size_t nleft; ssize_t nwrite; ssize_t total; const char *ptr; ptr = buf; nleft = *len; total = 0; while( nleft > 0){ if((nwrite = write(fd,ptr,*len))== -1){ perror("write all"); break; } nleft -= nwrite; ptr += nwrite; total += nwrite; *len = nleft; } *len = total; return (nwrite==-1)?-1:0; } /* read the commond from client, the command format is content+\r\n return value: 0: succesful -1: failure */ int read_cmd(int sockfd,char* cmd_buf,int len){ char line[MAX_LEN]; int my_len = 0; int total_len =0; char *ptr; int can_read; if(len > MAX_LEN) len = MAX_LEN; can_read = 1; strcpy(cmd_buf,"\0"); while(can_read){ if((my_len = read(sockfd, line,len))<0 ){ perror("read"); return -1; } total_len = total_len + my_len; if(total_len > len){ printf("Recieve command error!\n"); return -1; } if((ptr=strstr(line,"\r\n"))==NULL){ if(total_len <= len) strcat(cmd_buf, line); }else{ strncat(cmd_buf,line,ptr-line); can_read = 0; } printf("Client requests file: %s\n",cmd_buf); } return 0; } /* Send a file to client return value: 0: successful -1: failure */ int send_file(int sockfd,char *file_name) { int file_fd; int file_size; int read_left; int len; int error_flag; int readlen; struct stat file_state; char buffer[MAX_LEN]; int dot_number = 0; if((file_fd = open(file_name,O_RDONLY)) == -1){ perror("open"); return -1; } if(fstat(file_fd, &file_state)==-1){ perror("fstat"); return -1; } file_size = file_state.st_size; read_left = file_size; len = MAX_LEN; while(read_left > 0){ /* now read the file */ readlen = MAX_LEN; error_flag = readall(file_fd,buffer,&readlen); if(error_flag<0 ){ return -1; } read_left -= readlen; len = readlen; error_flag = writeall(sockfd,buffer,&len); if(error_flag == -1) return -1; if(readlen ==0 && read_left!=0){ printf("the file is not read fully!\n"); return -1; } if(read_left ==0){ printf("\nServer sent file over!\n"); } } close(file_fd); return 0; }