adding forgotten new file

1 files changed, 1130 insertions, 0 deletions

diff --git a/networking/ftpd.c b/networking/ftpd.c
new file mode 100644
index 0000000..ab7308b
--- /dev/null
+++ b/networking/ftpd.c
@@ -0,0 +1,1130 @@
+/* vi: set sw=4 ts=4: */
+/*
+ * Simple FTP daemon, based on vsftpd 2.0.7 (written by Chris Evans)
+ *
+ * Author: Adam Tkac <vonsch@gmail.com>
+ *
+ * Only subset of FTP protocol is implemented but vast majority of clients
+ * should not have any problem. You have to run this daemon via inetd.
+ *
+ * Options:
+ * -w	- enable FTP write commands
+ */
+
+#include "libbb.h"
+#include <netinet/tcp.h>
+
+enum {
+	FTP_DATACONN		= 150,
+	FTP_NOOPOK		= 200,
+	FTP_TYPEOK		= 200,
+	FTP_PORTOK		= 200,
+	FTP_STRUOK		= 200,
+	FTP_MODEOK		= 200,
+	FTP_ALLOOK		= 202,
+	FTP_STATOK		= 211,
+	FTP_STATFILE_OK		= 213,
+	FTP_HELP		= 214,
+	FTP_SYSTOK		= 215,
+	FTP_GREET		= 220,
+	FTP_GOODBYE		= 221,
+	FTP_TRANSFEROK		= 226,
+	FTP_PASVOK		= 227,
+	FTP_LOGINOK		= 230,
+	FTP_CWDOK		= 250,
+#if ENABLE_FEATURE_FTP_WRITE
+	FTP_RMDIROK		= 250,
+	FTP_DELEOK		= 250,
+	FTP_RENAMEOK		= 250,
+#endif
+	FTP_PWDOK		= 257,
+#if ENABLE_FEATURE_FTP_WRITE
+	FTP_MKDIROK		= 257,
+#endif
+	FTP_GIVEPWORD		= 331,
+	FTP_RESTOK		= 350,
+#if ENABLE_FEATURE_FTP_WRITE
+	FTP_RNFROK		= 350,
+#endif
+	FTP_BADSENDCONN		= 425,
+	FTP_BADSENDNET		= 426,
+	FTP_BADSENDFILE		= 451,
+	FTP_BADCMD		= 500,
+	FTP_COMMANDNOTIMPL	= 502,
+	FTP_NEEDUSER		= 503,
+	FTP_NEEDRNFR		= 503,
+	FTP_BADSTRU		= 504,
+	FTP_BADMODE		= 504,
+	FTP_LOGINERR		= 530,
+	FTP_FILEFAIL		= 550,
+	FTP_NOPERM		= 550,
+	FTP_UPLOADFAIL		= 553,
+
+#define mk_const4(a,b,c,d) (((a * 0x100 + b) * 0x100 + c) * 0x100 + d)
+#define mk_const3(a,b,c)    ((a * 0x100 + b) * 0x100 + c)
+	const_ALLO = mk_const4('A', 'L', 'L', 'O'),
+	const_APPE = mk_const4('A', 'P', 'P', 'E'),
+	const_CDUP = mk_const4('C', 'D', 'U', 'P'),
+	const_CWD  = mk_const3('C', 'W', 'D'),
+	const_DELE = mk_const4('D', 'E', 'L', 'E'),
+	const_HELP = mk_const4('H', 'E', 'L', 'P'),
+	const_LIST = mk_const4('L', 'I', 'S', 'T'),
+	const_MKD  = mk_const3('M', 'K', 'D'),
+	const_MODE = mk_const4('M', 'O', 'D', 'E'),
+	const_NLST = mk_const4('N', 'L', 'S', 'T'),
+	const_NOOP = mk_const4('N', 'O', 'O', 'P'),
+	const_PASS = mk_const4('P', 'A', 'S', 'S'),
+	const_PASV = mk_const4('P', 'A', 'S', 'V'),
+	const_PORT = mk_const4('P', 'O', 'R', 'T'),
+	const_PWD  = mk_const3('P', 'W', 'D'),
+	const_QUIT = mk_const4('Q', 'U', 'I', 'T'),
+	const_REST = mk_const4('R', 'E', 'S', 'T'),
+	const_RETR = mk_const4('R', 'E', 'T', 'R'),
+	const_RMD  = mk_const3('R', 'M', 'D'),
+	const_RNFR = mk_const4('R', 'N', 'F', 'R'),
+	const_RNTO = mk_const4('R', 'N', 'T', 'O'),
+	const_STAT = mk_const4('S', 'T', 'A', 'T'),
+	const_STOR = mk_const4('S', 'T', 'O', 'R'),
+	const_STOU = mk_const4('S', 'T', 'O', 'U'),
+	const_STRU = mk_const4('S', 'T', 'R', 'U'),
+	const_SYST = mk_const4('S', 'Y', 'S', 'T'),
+	const_TYPE = mk_const4('T', 'Y', 'P', 'E'),
+	const_USER = mk_const4('U', 'S', 'E', 'R'),
+};
+
+struct globals {
+	char *p_control_line_buf;
+	len_and_sockaddr *local_addr;
+	len_and_sockaddr *port_addr;
+	int pasv_listen_fd;
+	int data_fd;
+	off_t restart_pos;
+	char *ftp_cmp;
+	char *ftp_arg;
+#if ENABLE_FEATURE_FTP_WRITE
+	char *rnfr_filename;
+	smallint write_enable;
+#endif
+};
+#define G (*(struct globals*)&bb_common_bufsiz1)
+#define INIT_G() do { } while (0)
+
+
+static char *
+replace_text(const char *str, const char from, const char *to)
+{
+	size_t retlen, remainlen, chunklen, tolen;
+	const char *remain;
+	char *ret, *found;
+
+	remain = str;
+	remainlen = strlen(str);
+
+	tolen = strlen(to);
+
+	/* simply alloc strlen(str)*strlen(to). To is max 2 so it's allowed */
+	ret = xmalloc(remainlen * strlen(to) + 1);
+	retlen = 0;
+
+	for (;;) {
+		found = strchr(remain, from);
+		if (found != NULL) {
+			chunklen = found - remain;
+
+			/* Copy chunk which doesn't contain 'from' to ret */
+			memcpy(&ret[retlen], remain, chunklen);
+			retlen += chunklen;
+
+			/* Now copy 'to' instead of 'from' */
+			memcpy(&ret[retlen], to, tolen);
+			retlen += tolen;
+
+			remain = found + 1;
+		} else {
+			/*
+			 * The last chunk. We are already sure that we have enough space
+			 * so we can use strcpy.
+			 */
+			strcpy(&ret[retlen], remain);
+			break;
+		}
+	}
+	return ret;
+}
+
+static void
+replace_char(char *str, char from, char to)
+{
+	char *ptr;
+
+	/* Don't use strchr here...*/
+	while ((ptr = strchr(str, from)) != NULL) {
+		*ptr = to;
+		str = ptr + 1;
+	}
+}
+
+static void
+str_netfd_write(const char *str, int fd)
+{
+	xwrite(fd, str, strlen(str));
+}
+
+static void
+ftp_write_str_common(unsigned int status, const char *str, char sep)
+{
+	char *escaped_str, *response;
+	size_t len;
+
+	escaped_str = replace_text(str, '\377', "\377\377");
+
+	response = xasprintf("%u%c%s\r\n", status, sep, escaped_str);
+	free(escaped_str);
+
+	len = strlen(response);
+	replace_char(escaped_str, '\n', '\0');
+
+	/* Change trailing '\0' back to '\n' */
+	response[len - 1] = '\n';
+	xwrite(STDIN_FILENO, response, len);
+}
+
+static void
+cmdio_write(int status, const char *p_text)
+{
+	ftp_write_str_common(status, p_text, ' ');
+}
+
+static void
+cmdio_write_hyphen(int status, const char *p_text)
+{
+	ftp_write_str_common(status, p_text, '-');
+}
+
+static void
+cmdio_write_raw(const char *p_text)
+{
+	str_netfd_write(p_text, STDIN_FILENO);
+}
+
+static uint32_t
+cmdio_get_cmd_and_arg(void)
+{
+	int len;
+	uint32_t cmdval;
+	char *cmd;
+
+	free(G.ftp_cmp);
+	G.ftp_cmp = cmd = xmalloc_reads(STDIN_FILENO, NULL, NULL);
+/*
+ * TODO:
+ *
+ * now we should change all '\0' to '\n' - xmalloc_reads will be improved,
+ * probably
+ */
+	len = strlen(cmd) - 1;
+	while (len >= 0 && cmd[len] == '\r') {
+		cmd[len] = '\0';
+		len--;
+	}
+
+	G.ftp_arg = strchr(cmd, ' ');
+	if (G.ftp_arg != NULL) {
+		*G.ftp_arg = '\0';
+		G.ftp_arg++;
+	}
+	cmdval = 0;
+	while (*cmd)
+		cmdval = (cmdval << 8) + ((unsigned char)*cmd++ & (unsigned char)~0x20);
+
+	return cmdval;
+}
+
+static void
+init_data_sock_params(int sock_fd)
+{
+	struct linger linger;
+
+	G.data_fd = sock_fd;
+
+	memset(&linger, 0, sizeof(linger));
+	linger.l_onoff = 1;
+	linger.l_linger = 32767;
+
+	setsockopt(sock_fd, SOL_SOCKET, SO_KEEPALIVE, &const_int_1, sizeof(const_int_1));
+	setsockopt(sock_fd, SOL_SOCKET, SO_LINGER, &linger, sizeof(linger));
+}
+
+static int
+ftpdataio_get_pasv_fd(void)
+{
+	int remote_fd;
+
+	remote_fd = accept(G.pasv_listen_fd, NULL, 0);
+
+	if (remote_fd < 0) {
+		cmdio_write(FTP_BADSENDCONN, "Can't establish connection");
+		return remote_fd;
+	}
+
+	init_data_sock_params(remote_fd);
+	return remote_fd;
+}
+
+static int
+ftpdataio_get_port_fd(void)
+{
+	int remote_fd;
+
+	/* Do we want die or print error to client? */
+	remote_fd = xconnect_stream(G.port_addr);
+
+	init_data_sock_params(remote_fd);
+	return remote_fd;
+}
+
+static void
+ftpdataio_dispose_transfer_fd(void)
+{
+	/* This close() blocks because we set SO_LINGER */
+	if (G.data_fd > STDOUT_FILENO) {
+		if (close(G.data_fd) < 0) {
+			/* Do it again without blocking. */
+			struct linger linger;
+
+			memset(&linger, 0, sizeof(linger));
+			setsockopt(G.data_fd, SOL_SOCKET, SO_LINGER, &linger, sizeof(linger));
+			close(G.data_fd);
+		}
+	}
+	G.data_fd = -1;
+}
+
+static int
+port_active(void)
+{
+	return (G.port_addr != NULL) ? 1: 0;
+}
+
+static int
+pasv_active(void)
+{
+	return (G.pasv_listen_fd != -1) ? 1 : 0;
+}
+
+static int
+get_remote_transfer_fd(const char *p_status_msg)
+{
+	int remote_fd;
+
+	if (pasv_active())
+		remote_fd = ftpdataio_get_pasv_fd();
+	else
+		remote_fd = ftpdataio_get_port_fd();
+
+	if (remote_fd < 0)
+		return remote_fd;
+
+	cmdio_write(FTP_DATACONN, p_status_msg);
+	return remote_fd;
+}
+
+static void
+handle_pwd(void)
+{
+	char *cwd, *promoted_cwd, *response;
+
+	cwd = xrealloc_getcwd_or_warn(NULL);
+	if (cwd == NULL)
+		cwd = xstrdup("");
+
+	/* We _have to_ promote each " to "" */
+	promoted_cwd = replace_text(cwd, '\"', "\"\"");
+	free(cwd);
+	response = xasprintf("\"%s\"", promoted_cwd);
+	free(promoted_cwd);
+	cmdio_write(FTP_PWDOK, response);
+	free(response);
+}
+
+static void
+handle_cwd(void)
+{
+	int retval;
+
+	/* XXX Do we need check ftp_arg != NULL? */
+	retval = chdir(G.ftp_arg);
+	if (retval == 0)
+		cmdio_write(FTP_CWDOK, "Directory changed");
+	else
+		cmdio_write(FTP_FILEFAIL, "Can't change directory");
+}
+
+static void
+handle_cdup(void)
+{
+	G.ftp_arg = xstrdup("..");
+	handle_cwd();
+	free(G.ftp_arg);
+}
+
+static int
+data_transfer_checks_ok(void)
+{
+	if (!pasv_active() && !port_active()) {
+		cmdio_write(FTP_BADSENDCONN, "Use PORT or PASV first");
+		return 0;
+	}
+
+	return 1;
+}
+
+static void
+port_cleanup(void)
+{
+	if (G.port_addr != NULL)
+		free(G.port_addr);
+
+	G.port_addr = NULL;
+}
+
+static void
+pasv_cleanup(void)
+{
+	if (G.pasv_listen_fd > STDOUT_FILENO)
+		close(G.pasv_listen_fd);
+	G.pasv_listen_fd = -1;
+}
+
+static char *
+statbuf_getperms(const struct stat *statbuf)
+{
+	char *perms;
+	enum { r = 'r', w = 'w', x = 'x', s = 's', S = 'S' };
+
+	perms = xmalloc(11);
+	memset(perms, '-', 10);
+
+  	perms[0] = '?';
+	switch (statbuf->st_mode & S_IFMT) {
+	case S_IFREG: perms[0] = '-'; break;
+	case S_IFDIR: perms[0] = 'd'; break;
+	case S_IFLNK: perms[0] = 'l'; break;
+	case S_IFIFO: perms[0] = 'p'; break;
+	case S_IFSOCK: perms[0] = s; break;
+	case S_IFCHR: perms[0] = 'c'; break;
+	case S_IFBLK: perms[0] = 'b'; break;
+	}
+
+	if (statbuf->st_mode & S_IRUSR) perms[1] = r;
+	if (statbuf->st_mode & S_IWUSR) perms[2] = w;
+	if (statbuf->st_mode & S_IXUSR) perms[3] = x;
+	if (statbuf->st_mode & S_IRGRP) perms[4] = r;
+	if (statbuf->st_mode & S_IWGRP) perms[5] = w;
+	if (statbuf->st_mode & S_IXGRP) perms[6] = x;
+	if (statbuf->st_mode & S_IROTH) perms[7] = r;
+	if (statbuf->st_mode & S_IWOTH) perms[8] = w;
+	if (statbuf->st_mode & S_IXOTH) perms[9] = x;
+	if (statbuf->st_mode & S_ISUID) perms[3] = (perms[3] == x) ? s : S;
+	if (statbuf->st_mode & S_ISGID) perms[6] = (perms[6] == x) ? s : S;
+	if (statbuf->st_mode & S_ISVTX) perms[9] = (perms[9] == x) ? 't' : 'T';
+
+	perms[10] = '\0';
+
+	return perms;
+}
+
+static void
+write_filestats(int fd, const char *filename,
+				const struct stat *statbuf)
+{
+	off_t size;
+	char *stats, *lnkname = NULL, *perms;
+	const char *name;
+	int retval;
+	char timestr[32];
+	struct tm *tm;
+	const char *format = "%b %d %H:%M";
+
+	name = bb_get_last_path_component_nostrip(filename);
+
+	if (statbuf != NULL) {
+		size = statbuf->st_size;
+
+		if (S_ISLNK(statbuf->st_mode))
+			/* Damn symlink... */
+			lnkname = xmalloc_readlink(filename);
+
+		tm = gmtime(&statbuf->st_mtime);
+		retval = strftime(timestr, sizeof(timestr), format, tm);
+		if (retval == 0)
+			bb_error_msg_and_die("strftime");
+
+		timestr[sizeof(timestr) - 1] = '\0';
+
+		perms = statbuf_getperms(statbuf);
+
+		stats = xasprintf("%s %u\tftp ftp %"OFF_FMT"u\t%s %s",
+				perms, (int) statbuf->st_nlink,
+				size, timestr, name);
+
+		free(perms);
+	} else
+		stats = xstrdup(name);
+
+	str_netfd_write(stats, fd);
+	free(stats);
+	if (lnkname != NULL) {
+		str_netfd_write(" -> ", fd);
+		str_netfd_write(lnkname, fd);
+		free(lnkname);
+	}
+	str_netfd_write("\r\n", fd);
+}
+
+static void
+write_dirstats(int fd, const char *dname, int details)
+{
+	DIR *dir;
+	struct dirent *dirent;
+	struct stat statbuf;
+	char *filename;
+
+	dir = xopendir(dname);
+
+	for (;;) {
+		dirent = readdir(dir);
+		if (dirent == NULL)
+			break;
+
+		/* Ignore . and .. */
+		if (dirent->d_name[0] == '.') {
+			if (dirent->d_name[1] == '\0'
+			 || (dirent->d_name[1] == '.' && dirent->d_name[2] == '\0')
+			) {
+				continue;
+			}
+		}
+
+		if (details) {
+			filename = xasprintf("%s/%s", dname, dirent->d_name);
+			if (lstat(filename, &statbuf) != 0) {
+				free(filename);
+				goto bail;
+			}
+		} else
+			filename = xstrdup(dirent->d_name);
+
+		write_filestats(fd, filename, details ? &statbuf : NULL);
+		free(filename);
+	}
+
+bail:
+	closedir(dir);
+}
+
+static void
+handle_pasv(void)
+{
+	int bind_retries = 10;
+	unsigned short port;
+	enum { min_port = 1024, max_port = 65535 };
+	char *addr, *wire_addr, *response;
+
+	pasv_cleanup();
+	port_cleanup();
+	G.pasv_listen_fd = xsocket(G.local_addr->u.sa.sa_family, SOCK_STREAM, 0);
+	setsockopt_reuseaddr(G.pasv_listen_fd);
+
+	/* TODO bind() with port == 0 and then call getsockname */
+	while (--bind_retries) {
+		port = rand() % max_port;
+		if (port < min_port) {
+			port += min_port;
+		}
+
+		set_nport(G.local_addr, htons(port));
+		/* We don't want to use xbind, it'll die if port is in use */
+		if (bind(G.pasv_listen_fd, &G.local_addr->u.sa,	G.local_addr->len) != 0) {
+			/* do we want check if errno == EADDRINUSE ? */
+			continue;
+		}
+		xlisten(G.pasv_listen_fd, 1);
+		break;
+	}
+
+	if (!bind_retries)
+		bb_error_msg_and_die("can't create pasv socket");
+
+	addr = xmalloc_sockaddr2dotted_noport(&G.local_addr->u.sa);
+	wire_addr = replace_text(addr, '.', ",");
+	free(addr);
+
+	response = xasprintf("Entering Passive Mode (%s,%u,%u)",
+			wire_addr, (int)(port >> 8), (int)(port & 255));
+
+	cmdio_write(FTP_PASVOK, response);
+	free(wire_addr);
+	free(response);
+}
+
+static void
+handle_retr(void)
+{
+	struct stat statbuf;
+	int trans_ret, retval;
+	int remote_fd;
+	int opened_file;
+	off_t offset = G.restart_pos;
+	char *response;
+
+	G.restart_pos = 0;
+
+	if (!data_transfer_checks_ok())
+		return;
+
+	/* XXX Do we need check if ftp_arg != NULL? */
+	opened_file = open(G.ftp_arg, O_RDONLY | O_NONBLOCK);
+	if (opened_file < 0) {
+		cmdio_write(FTP_FILEFAIL, "Can't open file");
+		return;
+	}
+
+	retval = fstat(opened_file, &statbuf);
+	if (retval < 0 || !S_ISREG(statbuf.st_mode)) {
+		/* Note - pretend open failed */
+		cmdio_write(FTP_FILEFAIL, "Can't open file");
+		goto file_close_out;
+	}
+
+	/* Now deactive O_NONBLOCK, otherwise we have a problem on DMAPI filesystems
+	 * such as XFS DMAPI.
+	 */
+	ndelay_off(opened_file);
+
+	/* Set the download offset (from REST) if any */
+	if (offset != 0)
+		xlseek(opened_file, offset, SEEK_SET);
+
+	response = xasprintf(
+		"Opening BINARY mode data connection for (%s %"OFF_FMT"u bytes).",
+		G.ftp_arg, statbuf.st_size);
+
+	remote_fd = get_remote_transfer_fd(response);
+	free(response);
+	if (remote_fd < 0)
+		goto port_pasv_cleanup_out;
+
+	trans_ret = bb_copyfd_eof(opened_file, remote_fd);
+	ftpdataio_dispose_transfer_fd();
+	if (trans_ret < 0)
+		cmdio_write(FTP_BADSENDFILE, "Error sending local file");
+	else
+		cmdio_write(FTP_TRANSFEROK, "File sent OK");
+
+port_pasv_cleanup_out:
+	port_cleanup();
+	pasv_cleanup();
+file_close_out:
+	close(opened_file);
+}
+
+static void
+handle_dir_common(int full_details, int stat_cmd)
+{
+	int fd;
+	struct stat statbuf;
+
+	if (!stat_cmd && !data_transfer_checks_ok())
+		return;
+
+	if (stat_cmd) {
+		fd = STDIN_FILENO;
+		cmdio_write_hyphen(FTP_STATFILE_OK, "Status follows:");
+	} else {
+		fd = get_remote_transfer_fd("Here comes the directory listing");
+		if (fd < 0)
+			goto bail;
+	}
+
+	if (G.ftp_arg != NULL) {
+		if (lstat(G.ftp_arg, &statbuf) != 0) {
+			/* Dir doesn't exist => return ok to client */
+			goto bail;
+		}
+		if (S_ISREG(statbuf.st_mode) || S_ISLNK(statbuf.st_mode))
+			write_filestats(fd, G.ftp_arg, &statbuf);
+		else if (S_ISDIR(statbuf.st_mode))
+			write_dirstats(fd, G.ftp_arg, full_details);
+	} else
+		write_dirstats(fd, ".", full_details);
+
+bail:
+	/* Well, if we can't open directory/file it doesn't matter */
+	if (!stat_cmd) {
+		ftpdataio_dispose_transfer_fd();
+		pasv_cleanup();
+		port_cleanup();
+		cmdio_write(FTP_TRANSFEROK, "OK");
+	} else
+		cmdio_write(FTP_STATFILE_OK, "End of status");
+}
+
+static void
+handle_list(void)
+{
+	handle_dir_common(1, 0);
+}
+
+static void
+handle_type(void)
+{
+	if (G.ftp_arg
+	 && (  ((G.ftp_arg[0] | 0x20) == 'i' && G.ftp_arg[1] == '\0')
+	    || !strcasecmp(G.ftp_arg, "L8")
+	    || !strcasecmp(G.ftp_arg, "L 8")
+	    )
+	) {
+		cmdio_write(FTP_TYPEOK, "Switching to Binary mode");
+	} else {
+		cmdio_write(FTP_BADCMD, "Unrecognised TYPE command");
+	}
+}
+
+static void
+handle_port(void)
+{
+	unsigned short port;
+	char *raw = NULL, *port_part;
+	len_and_sockaddr *lsa = NULL;
+
+	pasv_cleanup();
+	port_cleanup();
+
+	if (G.ftp_arg == NULL)
+		goto bail;
+
+	raw = replace_text(G.ftp_arg, ',', ".");
+
+	port_part = strrchr(raw, '.');
+	if (port_part == NULL)
+		goto bail;
+
+	port = xatou16(&port_part[1]);
+	*port_part = '\0';
+
+	port_part = strrchr(raw, '.');
+	if (port_part == NULL)
+		goto bail;
+
+	port |= xatou16(&port_part[1]) << 8;
+	*port_part = '\0';
+
+	lsa = xdotted2sockaddr(raw, port);
+
+bail:
+	free(raw);
+
+	if (lsa == NULL) {
+		cmdio_write(FTP_BADCMD, "Illegal PORT command");
+		return;
+	}
+
+	G.port_addr = lsa;
+	cmdio_write(FTP_PORTOK, "PORT command successful. Consider using PASV");
+}
+
+#if ENABLE_FEATURE_FTP_WRITE
+static void
+handle_upload_common(int is_append, int is_unique)
+{
+	char *template = NULL;
+	int trans_ret;
+	int new_file_fd;
+	int remote_fd;
+
+	enum {
+		fileflags = O_CREAT | O_WRONLY | O_APPEND,
+	};
+
+	off_t offset = G.restart_pos;
+
+	G.restart_pos = 0;
+	if (!data_transfer_checks_ok())
+		return;
+
+	if (is_unique) {
+		template = xstrdup("uniq.XXXXXX");
+		/*
+		 * XXX Use mkostemp here? vsftpd opens file with O_CREAT, O_WRONLY, 
+		 * O_APPEND and O_EXCL flags...
+		 */
+		new_file_fd = mkstemp(template);
+	} else {
+		/* XXX Do we need check if ftp_arg != NULL? */
+		if (!is_append && offset == 0)
+			new_file_fd = open(G.ftp_arg, O_CREAT | O_WRONLY | O_APPEND | O_NONBLOCK | O_TRUNC, 0666);
+		else
+			new_file_fd = open(G.ftp_arg, O_CREAT | O_WRONLY | O_APPEND | O_NONBLOCK, 0666);
+	}
+
+	if (new_file_fd < 0) {
+		cmdio_write(FTP_UPLOADFAIL, "Can't create file");
+		return;
+	}
+
+	if (!is_append && offset != 0) {
+		/* warning, allows seek past end of file! Check for seek > size? */
+		xlseek(new_file_fd, offset, SEEK_SET);
+	}
+
+	if (is_unique) {
+		char *resp = xasprintf("FILE: %s", template);
+		remote_fd = get_remote_transfer_fd(resp);
+		free(resp);
+		free(template);
+	} else
+		remote_fd = get_remote_transfer_fd("Ok to send data");
+
+	if (remote_fd < 0)
+		goto bail;
+
+	trans_ret = bb_copyfd_eof(remote_fd, new_file_fd);
+	ftpdataio_dispose_transfer_fd();
+
+	if (trans_ret < 0)
+		cmdio_write(FTP_BADSENDFILE, "Failure writing to local file");
+	else
+		cmdio_write(FTP_TRANSFEROK, "File receive OK");
+
+bail:
+	port_cleanup();
+	pasv_cleanup();
+	close(new_file_fd);
+}
+
+static void
+handle_stor(void)
+{
+	handle_upload_common(0, 0);
+}
+
+static void
+handle_mkd(void)
+{
+	int retval;
+
+	/* Do we need check if ftp_arg != NULL? */
+	retval = mkdir(G.ftp_arg, 0770);
+	if (retval != 0) {
+		cmdio_write(FTP_FILEFAIL, "Create directory operation failed");
+		return;
+	}
+
+	cmdio_write(FTP_MKDIROK, "created");
+}
+
+static void
+handle_rmd(void)
+{
+	int retval;
+
+	/* Do we need check if ftp_arg != NULL? */
+	retval = rmdir(G.ftp_arg);
+	if (retval != 0)
+		cmdio_write(FTP_FILEFAIL, "rmdir failed");
+	else
+		cmdio_write(FTP_RMDIROK, "rmdir successful");
+}
+
+static void
+handle_dele(void)
+{
+	int retval;
+
+	/* Do we need check if ftp_arg != NULL? */
+	retval = unlink(G.ftp_arg);
+	if (retval != 0)
+		cmdio_write(FTP_FILEFAIL, "Delete failed");
+	else
+		cmdio_write(FTP_DELEOK, "Delete successful");
+}
+#endif /* ENABLE_FEATURE_FTP_WRITE */
+
+static void
+handle_rest(void)
+{
+	/* When ftp_arg == NULL simply restart from beginning */
+	G.restart_pos = xatoi_u(G.ftp_arg);
+	cmdio_write(FTP_RESTOK, "Restart OK");
+}
+
+#if ENABLE_FEATURE_FTP_WRITE
+static void
+handle_rnfr(void)
+{
+	struct stat statbuf;
+	int retval;
+
+	/* Clear old value */
+	free(G.rnfr_filename);
+
+	/* Does it exist? Do we need check if ftp_arg != NULL? */
+	retval = stat(G.ftp_arg, &statbuf);
+	if (retval == 0) {
+		/* Yes */
+		G.rnfr_filename = xstrdup(G.ftp_arg);
+		cmdio_write(FTP_RNFROK, "Ready for RNTO");
+	} else
+		cmdio_write(FTP_FILEFAIL, "RNFR command failed");
+}
+
+static void
+handle_rnto(void)
+{
+	int retval;
+
+	/* If we didn't get a RNFR, throw a wobbly */
+	if (G.rnfr_filename == NULL) {
+		cmdio_write(FTP_NEEDRNFR, "RNFR required first");
+		return;
+	}
+
+	/* XXX Do we need check if ftp_arg != NULL? */
+	retval = rename(G.rnfr_filename, G.ftp_arg);
+
+	free(G.rnfr_filename);
+
+	if (retval == 0)
+		cmdio_write(FTP_RENAMEOK, "Rename successful");
+	else
+		cmdio_write(FTP_FILEFAIL, "Rename failed");
+}
+#endif /* ENABLE_FEATURE_FTP_WRITE */
+
+static void
+handle_nlst(void)
+{
+	handle_dir_common(0, 0);
+}
+
+#if ENABLE_FEATURE_FTP_WRITE
+static void
+handle_appe(void)
+{
+	handle_upload_common(1, 0);
+}
+#endif
+
+static void
+handle_help(void)
+{
+	cmdio_write_hyphen(FTP_HELP, "Recognized commands:");
+	cmdio_write_raw(" ALLO CDUP CWD HELP LIST\r\n"
+			" MODE NLST NOOP PASS PASV PORT PWD QUIT\r\n"
+			" REST RETR STAT STRU SYST TYPE USER\r\n"
+#if ENABLE_FEATURE_FTP_WRITE
+			" APPE DELE MKD RMD RNFR RNTO STOR STOU\r\n"
+#endif
+	);
+	cmdio_write(FTP_HELP, "Help OK");
+}
+
+#if ENABLE_FEATURE_FTP_WRITE
+static void
+handle_stou(void)
+{
+	handle_upload_common(0, 1);
+}
+#endif
+
+static void
+handle_stat(void)
+{
+	cmdio_write_hyphen(FTP_STATOK, "FTP server status:");
+	cmdio_write_raw(" TYPE: BINARY\r\n");
+	cmdio_write(FTP_STATOK, "End of status");
+}
+
+static void
+handle_stat_file(void)
+{
+	handle_dir_common(1, 1);
+}
+
+/* TODO: libbb candidate (tftp has another copy) */
+static len_and_sockaddr *get_sock_lsa(int s)
+{
+	len_and_sockaddr *lsa;
+	socklen_t len = 0;
+
+	if (getsockname(s, NULL, &len) != 0)
+		return NULL;
+	lsa = xzalloc(LSA_LEN_SIZE + len);
+	lsa->len = len;
+	getsockname(s, &lsa->u.sa, &lsa->len);
+	return lsa;
+}
+
+int ftpd_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
+int ftpd_main(int argc UNUSED_PARAM, char **argv)
+{
+	smallint user_was_specified = 0;
+
+	INIT_G();
+
+	G.local_addr = get_sock_lsa(STDIN_FILENO);
+	if (!G.local_addr) {
+		/* This is confusing:
+		 * bb_error_msg_and_die("stdin is not a socket");
+		 * Better: */
+		bb_show_usage();
+		/* Help text says that ftpd must be used as inetd service,
+		 * which is by far the most usual cause of get_sock_lsa
+		 * failure */
+	}
+
+	logmode = LOGMODE_SYSLOG;
+
+	USE_FEATURE_FTP_WRITE(G.write_enable =) getopt32(argv, "" USE_FEATURE_FTP_WRITE("w"));
+	if (argv[optind]) {
+		xchdir(argv[optind]);
+		chroot(".");
+	}
+
+//	if (G.local_addr->u.sa.sa_family != AF_INET)
+//		bb_error_msg_and_die("Only IPv4 is supported");
+
+	/* Signals. We'll always take -EPIPE rather than a rude signal, thanks */
+	signal(SIGPIPE, SIG_IGN);
+
+	/* Set up options on the command socket */
+	setsockopt(STDIN_FILENO, IPPROTO_TCP, TCP_NODELAY, &const_int_1, sizeof(const_int_1));
+	setsockopt(STDIN_FILENO, SOL_SOCKET, SO_KEEPALIVE, &const_int_1, sizeof(const_int_1));
+	setsockopt(STDIN_FILENO, SOL_SOCKET, SO_OOBINLINE, &const_int_1, sizeof(const_int_1));
+
+	cmdio_write(FTP_GREET, "Welcome");
+
+	while (1) {
+		uint32_t cmdval = cmdio_get_cmd_and_arg();
+
+		if (cmdval == const_USER) {
+			if (G.ftp_arg == NULL || strcasecmp(G.ftp_arg, "anonymous") != 0)
+				cmdio_write(FTP_LOGINERR, "Server is anonymous only");
+			else {
+				user_was_specified = 1;
+				cmdio_write(FTP_GIVEPWORD, "Please specify the password");
+			}
+		} else if (cmdval == const_PASS) {
+			if (user_was_specified)
+				break;
+			cmdio_write(FTP_NEEDUSER, "Login with USER");
+		} else if (cmdval == const_QUIT) {
+			cmdio_write(FTP_GOODBYE, "Goodbye");
+			return 0;
+		} else {
+			cmdio_write(FTP_LOGINERR,
+				"Login with USER and PASS");
+		}
+	}
+
+	umask(077);
+	cmdio_write(FTP_LOGINOK, "Login successful");
+
+	while (1) {
+		uint32_t cmdval = cmdio_get_cmd_and_arg();
+
+		if (cmdval == const_QUIT) {
+			cmdio_write(FTP_GOODBYE, "Goodbye");
+			return 0;
+		}
+		if (cmdval == const_PWD)
+			handle_pwd();
+		else if (cmdval == const_CWD)
+			handle_cwd();
+		else if (cmdval == const_CDUP)
+			handle_cdup();
+		else if (cmdval == const_PASV)
+			handle_pasv();
+		else if (cmdval == const_RETR)
+			handle_retr();
+		else if (cmdval == const_NOOP)
+			cmdio_write(FTP_NOOPOK, "NOOP ok");
+		else if (cmdval == const_SYST)
+			cmdio_write(FTP_SYSTOK, "UNIX Type: L8");
+		else if (cmdval == const_HELP)
+			handle_help();
+		else if (cmdval == const_LIST)
+			handle_list();
+		else if (cmdval == const_TYPE)
+			handle_type();
+		else if (cmdval == const_PORT)
+			handle_port();
+		else if (cmdval == const_REST)
+			handle_rest();
+		else if (cmdval == const_NLST)
+			handle_nlst();
+#if ENABLE_FEATURE_FTP_WRITE
+		else if (G.write_enable) {
+			if (cmdval == const_STOR)
+				handle_stor();
+			else if (cmdval == const_MKD)
+				handle_mkd();
+			else if (cmdval == const_RMD)
+				handle_rmd();
+			else if (cmdval == const_DELE)
+				handle_dele();
+			else if (cmdval == const_RNFR)
+				handle_rnfr();
+			else if (cmdval == const_RNTO)
+				handle_rnto();
+			else if (cmdval == const_APPE)
+				handle_appe();
+			else if (cmdval == const_STOU)
+				handle_stou();
+		}
+#endif
+		else if (cmdval == const_STRU) {
+			if (G.ftp_arg
+			 && (G.ftp_arg[0] | 0x20) == 'f'
+			 && G.ftp_arg[1] == '\0'
+			) {
+				cmdio_write(FTP_STRUOK, "Structure set to F");
+			} else
+				cmdio_write(FTP_BADSTRU, "Bad STRU command");
+
+		} else if (cmdval == const_MODE) {
+			if (G.ftp_arg
+			 && (G.ftp_arg[0] | 0x20) == 's'
+			 && G.ftp_arg[1] == '\0'
+			) {
+				cmdio_write(FTP_MODEOK, "Mode set to S");
+			} else
+				cmdio_write(FTP_BADMODE, "Bad MODE command");
+		}
+		else if (cmdval == const_ALLO)
+			cmdio_write(FTP_ALLOOK, "ALLO command ignored");
+		else if (cmdval == const_STAT) {
+			if (G.ftp_arg == NULL)
+				handle_stat();
+			else
+				handle_stat_file();
+		} else if (cmdval == const_USER)
+			cmdio_write(FTP_LOGINERR, "Can't change to another user");
+		else if (cmdval == const_PASS)
+			cmdio_write(FTP_LOGINOK, "Already logged in");
+		else if (cmdval == const_STOR
+		 || cmdval == const_MKD
+		 || cmdval == const_RMD
+		 || cmdval == const_DELE
+		 || cmdval == const_RNFR
+		 || cmdval == const_RNTO
+		 || cmdval == const_APPE
+		 || cmdval == const_STOU
+		) {
+			cmdio_write(FTP_NOPERM, "Permission denied");
+		} else {
+			cmdio_write(FTP_BADCMD, "Unknown command");
+		}
+	}
+}