linux c开发的ftp服务器程序

#include <sys/types.h> #include <unistd.h> #include <stdio.h> #include <stdlib.h> #include <errno.h> #include <string.h> #include <sys/stat.h> #include <time.h> #include <sys/socket.h> #include <netinet/in.h> #include <arpa/inet.h> #include <netdb.h> #include <stdarg.h> #include <signal.h> #include <sys/wait.h> #include <fcntl.h> #include <pwd.h> #include <grp.h> #include <dirent.h> #define CUFTPD_DEBUG(fmt, ...) cuftpd_debug(__FILE__, __LINE__, fmt, __VA_ARGS__) #define CUFTPD_ARR_LEN(arr) (sizeof(arr)/sizeof(arr[0])) #define CUFTPD_VER "1.0" #define CUFTPD_DEF_SRV_PORT 21 #define CUFTPD_LISTEN_QU_LEN 8 #define CUFTPD_LINE_END "\r\n" #define CUFTPD_OK 0 #define CUFTPD_ERR (-1) #define CUFTPD_CHECK_LOGIN() \ do { \ if (!cuftpd_cur_user) { \ cuftpd_send_resp(ctrlfd, 530, "first please"); \ return CUFTPD_ERR; \ } \ } while(0) struct cuftpd_cmd_struct { char *cmd_name; int (*cmd_handler)(int ctrlfd, char *cmd_line); }; struct cuftpd_user_struct { char user[128]; char pass[128]; }; /* local functions declarations */ static int cuftpd_do_user(int,char*); static int cuftpd_do_pass(int,char*); static int cuftpd_do_pwd(int, char*); static int cuftpd_do_cwd(int, char*); static int cuftpd_do_syst(int,char*); static int cuftpd_do_list(int,char*); static int cuftpd_do_size(int,char*); static int cuftpd_do_dele(int,char*); static int cuftpd_do_type(int,char*); static int cuftpd_do_port(int,char*); static int cuftpd_do_pasv(int,char*); static int cuftpd_do_retr(int,char*); static int cuftpd_do_stor(int,char*); static int cuftpd_do_quit(int,char*); /* global variables */ int cuftpd_debug_on; int cuftpd_srv_port = CUFTPD_DEF_SRV_PORT; int cuftpd_cur_child_num; int cuftpd_quit_flag; struct cuftpd_user_struct *cuftpd_cur_user; int cuftpd_pasv_fd = -1; int cuftpd_pasv_connfd = -1; int cuftpd_port_connfd = -1; char cuftpd_home_dir[PATH_MAX]; /* * Currently supported ftp commands. */ struct cuftpd_cmd_struct cuftpd_cmds[] = { {"USER", cuftpd_do_user}, {"PASS", }, {"PWD", cuftpd_do_pwd}, {"XPWD", cuftpd_do_pwd}, {"CWD", cuftpd_do_cwd}, {"LIST", cuftpd_do_list}, {"NLST", cuftpd_do_list}, {"SYST", cuftpd_do_syst}, {"TYPE", cuftpd_do_type}, {"SIZE", cuftpd_do_size}, {"DELE", cuftpd_do_dele}, {"RMD", cuftpd_do_dele}, {"PORT", cuftpd_do_port}, {"PASV", cuftpd_do_pasv}, {"RETR", cuftpd_do_retr}, {"STOR", cuftpd_do_stor}, {"QUIT", cuftpd_do_quit}, { NULL, NULL} }; /* * Anonymous users, you can add more user/pass pairs here. */ struct cuftpd_user_struct cuftpd_users[] = { {"anonymous", ""}, {"ftp", ""} }; /* * Ftp server's responses, and are not complete. */ char cuftpd_srv_resps[][256] = { "150 Begin transfer" CUFTPD_LINE_END, "200 OK" CUFTPD_LINE_END, "213 %d" CUFTPD_LINE_END, "215 UNIX Type: L8" CUFTPD_LINE_END, "220 CuFTPD " CUFTPD_VER " Server" CUFTPD_LINE_END, "221 Goodbye" CUFTPD_LINE_END, "226 Transfer complete" CUFTPD_LINE_END, "227 Entering Passive Mode (%d,%d,%d,%d,%d,%d)" CUFTPD_LINE_END, "230 User %s logged in" CUFTPD_LINE_END, "250 CWD command successful" CUFTPD_LINE_END, "257 \"%s\" is current directory" CUFTPD_LINE_END, "331 Password required for %s" CUFTPD_LINE_END, "500 Unsupport command %s" CUFTPD_LINE_END, "530 Login %s" CUFTPD_LINE_END, "550 Error" CUFTPD_LINE_END }; static void cuftpd_debug(const char *file, int line, const char *fmt, ...) { va_list ap; if (!cuftpd_debug_on) return; fprintf(stderr, "(%s:%d:%d)", file, line, getpid()); va_start(ap, fmt); vfprintf(stderr, fmt, ap); va_end(ap); } static void cuftpd_usage(void) { printf("cuftpd " CUFTPD_VER " usage:\n"); printf("cuftpd -p port -d\n"); } static void cuftpd_parse_args(int argc, char *argv[]) { int opt; int err = 0; while ((opt = getopt(argc, argv, "p:dh")) != -1) { switch (opt) { case 'p': cuftpd_srv_port = atoi(optarg); err = (cuftpd_srv_port < 0 || cuftpd_srv_port > 65535); break; case 'd': cuftpd_debug_on = 1; break; default: err = 1; break; } if (err) { cuftpd_usage(); exit(-1); } } CUFTPD_DEBUG("srv port:%d\n", cuftpd_srv_port); } static void cuftpd_sigchild(int signo) { int status; if (signo != SIGCHLD) return; while (waitpid(-1, &status, WNOHANG) > 0) cuftpd_cur_child_num--; CUFTPD_DEBUG("caught a SIGCHLD, cuftpd_cur_child_num=%d\n", cuftpd_cur_child_num); } static int cuftpd_init(void) { /* add all init statements here */ signal(SIGPIPE, SIG_IGN); signal(SIGCHLD, cuftpd_sigchild); getcwd(cuftpd_home_dir, sizeof(cuftpd_home_dir)); return CUFTPD_OK; } /* * Create ftp server's listening socket. */ static int cuftpd_create_srv(void) { int fd; int on = 1; int err; struct sockaddr_in srvaddr; if ((fd = socket(AF_INET, SOCK_STREAM, 0)) < 0) { CUFTPD_DEBUG("socket() failed: %s\n", strerror(errno)); return fd; } err = setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)); if (err < 0) { CUFTPD_DEBUG("setsockopt() failed: %s\n", strerror(errno)); close(fd); return CUFTPD_ERR; } memset(&srvaddr, 0, sizeof(srvaddr)); srvaddr.sin_family = AF_INET; srvaddr.sin_port = htons(cuftpd_srv_port); srvaddr.sin_addr.s_addr = htonl(INADDR_ANY); err = bind(fd, (struct sockaddr*)&srvaddr, sizeof(srvaddr)); if (err < 0) { CUFTPD_DEBUG("bind() failed: %s\n", strerror(errno)); close(fd); return CUFTPD_ERR; } err = listen(fd, CUFTPD_LISTEN_QU_LEN); if (err < 0) { CUFTPD_DEBUG("listen() failed: %s\n", strerror(errno)); close(fd); return CUFTPD_ERR; } if (cuftpd_debug_on) { int len = sizeof(srvaddr); getsockname(fd, (struct sockaddr*)&srvaddr, &len); CUFTPD_DEBUG("create srv listen socket OK: %s:%d\n", inet_ntoa(srvaddr.sin_addr), ntohs(srvaddr.sin_port)); } return fd; } /* * Map server response's number to the msg pointer. */ static char * cuftpd_srv_resp_num2msg(int num) { int i; char buf[8]; snprintf(buf, sizeof(buf), "%d", num); if (strlen(buf) != 3) return NULL; for (i = 0; i < CUFTPD_ARR_LEN(cuftpd_srv_resps); i++) if (strncmp(buf, cuftpd_srv_resps[i], strlen(buf)) == 0) return cuftpd_srv_resps[i]; return NULL; } static int cuftpd_send_msg(int fd, char *msg, int len) { int n, off = 0, left = len; while (1) { n = write(fd, msg + off, left); if (n < 0) { if (errno == EINTR) continue; return n; } if (n < left) { left -= n; off += n; continue; } return len; } } static int cuftpd_recv_msg(int fd, char buf[], int len) { int n; while (1) { n = read(fd, buf, len); if (n < 0) { if (errno == EINTR) continue; return n; } return n; } } static int cuftpd_send_resp(i