简单的FTP服务器实现

#include <stdio.h> #include <sys/types.h> #include <sys/socket.h> #include <netinet/in.h> #include <arpa/inet.h> #include <string.h> #include <unistd.h> #include <dirent.h> #include <sys/stat.h> #include <fcntl.h> #include <stdlib.h> #include <netdb.h> #define CMD_LS 0x01 #define CMD_GET_FILE 0x02 #define MAGIC "55AA" #define LS_BUF MAGIC"LS" #define GET_BUF MAGIC"GET" #define BUFSIZE 100 struct cmd_t { int cmdid; char buf[100]; }; struct cmd_t parse(char *buf,int size) { struct cmd_t cmd; bzero(cmd.buf,sizeof(cmd.buf)); if(strcmp(buf,LS_BUF) == 0) { cmd.cmdid = CMD_LS; } if(strncmp(buf,GET_BUF,strlen(GET_BUF)) == 0) { cmd.cmdid = CMD_GET_FILE; strncpy(cmd.buf,buf + strlen(GET_BUF),(strlen(buf) - strlen(GET_BUF))); } return cmd; } int FtpServer() { int port = 2001; int sd; struct sockaddr_in addr; int maxclient = 10; int ret = 0, len; socklen_t socklen; pid_t pid; char sbuf[BUFSIZE] = {0}; char rbuf[BUFSIZE] = {0}; sd = socket(AF_INET,SOCK_STREAM,0); if(sd < 0) { printf("fail to create a socket\n"); return -1; } bzero((char*)&addr,sizeof(addr)); addr.sin_family = AF_INET; addr.sin_addr.s_addr = htonl(INADDR_ANY); addr.sin_port = htons(port); if(bind(sd,(struct sockaddr*)&addr,sizeof(addr)) < 0) { printf("fail to bind\n"); return -1; } if(listen(sd,maxclient) < 0) { printf("fail to listen\n"); return -1; } printf("waiting ...\n"); while(1) { struct sockaddr_in caddr; socklen = sizeof(caddr); int csd = accept(sd,(struct sockaddr*)&caddr,&socklen); if(csd < 0) { printf("fail to accpet\n"); return -1; } /*建立子进程*/ pid = fork(); if(pid > 0) { /*在父进程中，关闭connected socket*/ close(csd); /*监听while开头*/ continue; } else if(pid == 0) { if(fork() > 0) { close(csd); exit(0); } printf("the client address is: %s, port is: %d\n", inet_ntoa(caddr.sin_addr),caddr.sin_port); read(csd,rbuf,BUFSIZE); struct cmd_t cmd = parse(rbuf,strlen(rbuf)); if(cmd.cmdid == CMD_LS) { char buffer[100] = {0}; ls(".",buffer,100); write(csd,buffer,strlen(buffer)); } else if(cmd.cmdid == CMD_GET_FILE) { int fd = open(cmd.buf,O_RDONLY); char buffer_file[BUFSIZE] = {0}; int ret; while(1) { bzero(buffer_file,BUFSIZE); ret = 0; if((ret = read(fd,buffer_file,BUFSIZE -1)) <= 0) break; buffer_file[ret]='\0'; printf("file buf:%s\n",buffer_file); write(csd,buffer_file,strlen(buffer_file)); } close(fd); } else { printf("Server Fail"); } close(csd); } } close(sd); } int ls(const char *dir,char* buf,int size) { DIR* dir_p; struct dirent* ptr; int count = 0; if((dir_p = opendir(dir)) == NULL) { printf("fail to open the dir %s",dir); return -1; } while(( ptr = readdir(dir_p)) != NULL) { if(!strcmp(ptr->d_name,".") || !strcmp(ptr->d_name,"..")) { continue; } //sbuf[]=ptr->d_name; strncpy((buf + strlen(buf)),ptr->d_name,strlen(ptr->d_name)); buf[strlen(buf)] = ','; buf[strlen(buf) + 1] = '\0'; } return closedir(dir_p); } int main() { FtpServer(); } #if 0 if(write(csd,sbuf,strlen(sbuf)) < 0) { printf("fail to write to client\n"); ret = -1; break; } sleep(1); if((len = read(csd,rbuf,BUFSIZE)) < 0) { printf("fail to read from client\n"); ret = -1; break; } else if(len == 0) { break; } rbuf[len] = '\0'; printf("From client: %s",rbuf); } close(csd); } close(sd); return ret; } #endif #if 0 int ls(char *dir) { DIR* dir_p; struct dirent* ptr; int count = 0; if((dir_p = opendir(dir)) == NULL) { printf("fail to open the dir %s",dir); return -1; } while(( ptr = readdir(dir_p)) != NULL) { if(!strcmp(ptr->d_name,".") || !strcmp(ptr->d_name,"..")) { continue; } sbuf[]=ptr->d_name; count++; if(count % 5 == 0) printf("\n"); } while(1) { int csd = accept(sd,(struct sockaddr*)&caddr,&socklen); if(write(csd,sbuf,strlen(sbuf)) < 0) { printf("fail to write to client\n"); ret = -1; break; } sleep(1); if((len = read(csd,rbuf,BUFSIZE)) < 0) { printf("fail to read from client\n"); ret = -1; break; } else if(len == 0) { break; } rbuf[len] = '\0'; printf("From client: %s",rbuf); } printf("\n"); return closedir(dir_p); } int get_file() { } int multi_usr() { } int main(int argc,char **argv) { TCPServer(); if(argv=="ls") ls("/home/newtry1"); else if(argv=="get_file") get_file(); else if (argv=="multi_usr") multi_usr(); else printf("Please input right command:ls,get_file or multi_usr"); } #endif