linux下多线程文件服务器

/**************************************************************************************/ /*文件：rw.c */ /*简介：自定义I/O函数实现文件。 */ /*************************************************************************************/ #include <sys/types.h> #include <stdio.h> #include <unistd.h> #include <sys/stat.h> #include <fcntl.h> #include <string.h> #include "rw.h" /*read()函数的扩展，解决读不全的问题*/ 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; /*反复读，直到没有新的数据可读*/ 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; } /*write()函数的扩展，解决写不够的问题*/ 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; /*反复写，直到所有的数据都写入*/ 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; } /*分析客户端的命令，提取出请求的文件名*/ 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 += 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; } /*发送文件至客户端*/ 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; }