- (djm) Merge cygwin support from Corinna Vinschen <vinschen@cygnus.com>

[openssh.git] / scp.c

/*
 *
 * scp - secure remote copy.  This is basically patched BSD rcp which uses ssh
 * to do the data transfer (instead of using rcmd).
 *
 * NOTE: This version should NOT be suid root.  (This uses ssh to do the transfer
 * and ssh has the necessary privileges.)
 *
 * 1995 Timo Rinne <tri@iki.fi>, Tatu Ylonen <ylo@cs.hut.fi>
 *
*/

/*
 * Parts from:
 *
 * Copyright (c) 1983, 1990, 1992, 1993, 1995
 *	The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 */

#include "includes.h"
RCSID("$OpenBSD: scp.c,v 1.37 2000/09/01 15:25:13 deraadt Exp $");

#include "ssh.h"
#include "xmalloc.h"
#include <utime.h>

#define _PATH_CP "cp"

/* For progressmeter() -- number of seconds before xfer considered "stalled" */
#define STALLTIME	5

/* Progress meter bar */
#define BAR \
	"************************************************************"\
	"************************************************************"\
	"************************************************************"\
	"************************************************************"
#define MAX_BARLENGTH (sizeof(BAR) - 1)

/* Visual statistics about files as they are transferred. */
void progressmeter(int);

/* Returns width of the terminal (for progress meter calculations). */
int getttywidth(void);
int do_cmd(char *host, char *remuser, char *cmd, int *fdin, int *fdout, int argc);

/* Time a transfer started. */
static struct timeval start;

/* Number of bytes of current file transferred so far. */
volatile unsigned long statbytes;

/* Total size of current file. */
off_t totalbytes = 0;

/* Name of current file being transferred. */
char *curfile;

/* This is set to non-zero if IPv4 is desired. */
int IPv4 = 0;

/* This is set to non-zero if IPv6 is desired. */
int IPv6 = 0;

/* This is set to non-zero to enable verbose mode. */
int verbose_mode = 0;

/* This is set to non-zero if compression is desired. */
int compress_flag = 0;

/* This is set to zero if the progressmeter is not desired. */
int showprogress = 1;

/* This is set to non-zero if running in batch mode (that is, password
   and passphrase queries are not allowed). */
int batchmode = 0;

/* This is set to the cipher type string if given on the command line. */
char *cipher = NULL;

/* This is set to the RSA authentication identity file name if given on
   the command line. */
char *identity = NULL;

/* This is the port to use in contacting the remote site (is non-NULL). */
char *port = NULL;

/* This is the program to execute for the secured connection. ("ssh" or -S) */
char *ssh_program = SSH_PROGRAM;

/*
 * This function executes the given command as the specified user on the
 * given host.  This returns < 0 if execution fails, and >= 0 otherwise. This
 * assigns the input and output file descriptors on success.
 */

int
do_cmd(char *host, char *remuser, char *cmd, int *fdin, int *fdout, int argc)
{
	int pin[2], pout[2], reserved[2];

	if (verbose_mode)
		fprintf(stderr, "Executing: host %s, user %s, command %s\n",
		    host, remuser ? remuser : "(unspecified)", cmd);

	/*
	 * Reserve two descriptors so that the real pipes won't get
	 * descriptors 0 and 1 because that will screw up dup2 below.
	 */
	pipe(reserved);

	/* Create a socket pair for communicating with ssh. */
	if (pipe(pin) < 0)
		fatal("pipe: %s", strerror(errno));
	if (pipe(pout) < 0)
		fatal("pipe: %s", strerror(errno));

	/* Free the reserved descriptors. */
	close(reserved[0]);
	close(reserved[1]);

	/* For a child to execute the command on the remote host using ssh. */
	if (fork() == 0) {
		char *args[100];	/* XXX careful */
		unsigned int i;

		/* Child. */
		close(pin[1]);
		close(pout[0]);
		dup2(pin[0], 0);
		dup2(pout[1], 1);
		close(pin[0]);
		close(pout[1]);

		i = 0;
		args[i++] = ssh_program;
		args[i++] = "-x";
		args[i++] = "-oFallBackToRsh no";
		if (IPv4)
			args[i++] = "-4";
		if (IPv6)
			args[i++] = "-6";
		if (verbose_mode)
			args[i++] = "-v";
		if (compress_flag)
			args[i++] = "-C";
		if (batchmode)
			args[i++] = "-oBatchMode yes";
		if (cipher != NULL) {
			args[i++] = "-c";
			args[i++] = cipher;
		}
		if (identity != NULL) {
			args[i++] = "-i";
			args[i++] = identity;
		}
		if (port != NULL) {
			args[i++] = "-p";
			args[i++] = port;
		}
		if (remuser != NULL) {
			args[i++] = "-l";
			args[i++] = remuser;
		}
		args[i++] = host;
		args[i++] = cmd;
		args[i++] = NULL;

		execvp(ssh_program, args);
		perror(ssh_program);
		exit(1);
	}
	/* Parent.  Close the other side, and return the local side. */
	close(pin[0]);
	*fdout = pin[1];
	close(pout[1]);
	*fdin = pout[0];
	return 0;
}

void
fatal(const char *fmt,...)
{
	va_list ap;
	char buf[1024];

	va_start(ap, fmt);
	vsnprintf(buf, sizeof(buf), fmt, ap);
	va_end(ap);
	fprintf(stderr, "%s\n", buf);
	exit(255);
}

typedef struct {
	int cnt;
	char *buf;
} BUF;

extern int iamremote;

BUF *allocbuf(BUF *, int, int);
char *colon(char *);
void lostconn(int);
void nospace(void);
int okname(char *);
void run_err(const char *,...);
void verifydir(char *);

struct passwd *pwd;
uid_t userid;
int errs, remin, remout;
int pflag, iamremote, iamrecursive, targetshouldbedirectory;

#define	CMDNEEDS	64
char cmd[CMDNEEDS];		/* must hold "rcp -r -p -d\0" */

int response(void);
void rsource(char *, struct stat *);
void sink(int, char *[]);
void source(int, char *[]);
void tolocal(int, char *[]);
void toremote(char *, int, char *[]);
void usage(void);

int
main(argc, argv)
	int argc;
	char *argv[];
{
	int ch, fflag, tflag;
	char *targ;
	extern char *optarg;
	extern int optind;

	fflag = tflag = 0;
	while ((ch = getopt(argc, argv, "dfprtvBCc:i:P:q46S:")) != EOF)
		switch (ch) {
		/* User-visible flags. */
		case '4':
			IPv4 = 1;
			break;
		case '6':
			IPv6 = 1;
			break;
		case 'p':
			pflag = 1;
			break;
		case 'P':
			port = optarg;
			break;
		case 'r':
			iamrecursive = 1;
			break;
		case 'S':
			ssh_program = optarg;
			break;

		/* Server options. */
		case 'd':
			targetshouldbedirectory = 1;
			break;
		case 'f':	/* "from" */
			iamremote = 1;
			fflag = 1;
			break;
		case 't':	/* "to" */
			iamremote = 1;
			tflag = 1;
			break;
		case 'c':
			cipher = optarg;
			break;
		case 'i':
			identity = optarg;
			break;
		case 'v':
			verbose_mode = 1;
			break;
		case 'B':
			batchmode = 1;
			break;
		case 'C':
			compress_flag = 1;
			break;
		case 'q':
			showprogress = 0;
			break;
		case '?':
		default:
			usage();
		}
	argc -= optind;
	argv += optind;

	if ((pwd = getpwuid(userid = getuid())) == NULL)
		fatal("unknown user %d", (int) userid);

	if (!isatty(STDERR_FILENO))
		showprogress = 0;

	remin = STDIN_FILENO;
	remout = STDOUT_FILENO;

	if (fflag) {	
		/* Follow "protocol", send data. */
		(void) response();
		source(argc, argv);
		exit(errs != 0);
	}
	if (tflag) {
		/* Receive data. */
		sink(argc, argv);
		exit(errs != 0);
	}
	if (argc < 2)
		usage();
	if (argc > 2)
		targetshouldbedirectory = 1;

	remin = remout = -1;
	/* Command to be executed on remote system using "ssh". */
	(void) sprintf(cmd, "scp%s%s%s%s", verbose_mode ? " -v" : "",
	    iamrecursive ? " -r" : "", pflag ? " -p" : "",
	    targetshouldbedirectory ? " -d" : "");

	(void) signal(SIGPIPE, lostconn);

	if ((targ = colon(argv[argc - 1])))	/* Dest is remote host. */
		toremote(targ, argc, argv);
	else {
		tolocal(argc, argv);	/* Dest is local host. */
		if (targetshouldbedirectory)
			verifydir(argv[argc - 1]);
	}
	exit(errs != 0);
}

char *
cleanhostname(host)
	char *host;
{
	if (*host == '[' && host[strlen(host) - 1] == ']') {
		host[strlen(host) - 1] = '\0';
		return (host + 1);
	} else
		return host;
}

void
toremote(targ, argc, argv)
	char *targ, *argv[];
	int argc;
{
	int i, len;
	char *bp, *host, *src, *suser, *thost, *tuser;

	*targ++ = 0;
	if (*targ == 0)
		targ = ".";

	if ((thost = strchr(argv[argc - 1], '@'))) {
		/* user@host */
		*thost++ = 0;
		tuser = argv[argc - 1];
		if (*tuser == '\0')
			tuser = NULL;
		else if (!okname(tuser))
			exit(1);
	} else {
		thost = argv[argc - 1];
		tuser = NULL;
	}

	for (i = 0; i < argc - 1; i++) {
		src = colon(argv[i]);
		if (src) {	/* remote to remote */
			*src++ = 0;
			if (*src == 0)
				src = ".";
			host = strchr(argv[i], '@');
			len = strlen(ssh_program) + strlen(argv[i]) +
			    strlen(src) + (tuser ? strlen(tuser) : 0) +
			    strlen(thost) + strlen(targ) + CMDNEEDS + 32;
			bp = xmalloc(len);
			if (host) {
				*host++ = 0;
				host = cleanhostname(host);
				suser = argv[i];
				if (*suser == '\0')
					suser = pwd->pw_name;
				else if (!okname(suser))
					continue;
				(void) sprintf(bp,
				    "%s%s -x -o'FallBackToRsh no' -n -l %s %s %s %s '%s%s%s:%s'",
				     ssh_program, verbose_mode ? " -v" : "",
				     suser, host, cmd, src,
				     tuser ? tuser : "", tuser ? "@" : "",
				     thost, targ);
			} else {
				host = cleanhostname(argv[i]);
				(void) sprintf(bp,
				    "exec %s%s -x -o'FallBackToRsh no' -n %s %s %s '%s%s%s:%s'",
				     ssh_program, verbose_mode ? " -v" : "",
				     host, cmd, src,
				     tuser ? tuser : "", tuser ? "@" : "",
				     thost, targ);
			}
			if (verbose_mode)
				fprintf(stderr, "Executing: %s\n", bp);
			(void) system(bp);
			(void) xfree(bp);
		} else {	/* local to remote */
			if (remin == -1) {
				len = strlen(targ) + CMDNEEDS + 20;
				bp = xmalloc(len);
				(void) sprintf(bp, "%s -t %s", cmd, targ);
				host = cleanhostname(thost);
				if (do_cmd(host, tuser, bp, &remin,
				    &remout, argc) < 0)
					exit(1);
				if (response() < 0)
					exit(1);
				(void) xfree(bp);
			}
			source(1, argv + i);
		}
	}
}

void
tolocal(argc, argv)
	int argc;
	char *argv[];
{
	int i, len;
	char *bp, *host, *src, *suser;

	for (i = 0; i < argc - 1; i++) {
		if (!(src = colon(argv[i]))) {	/* Local to local. */
			len = strlen(_PATH_CP) + strlen(argv[i]) +
			    strlen(argv[argc - 1]) + 20;
			bp = xmalloc(len);
			(void) sprintf(bp, "exec %s%s%s %s %s", _PATH_CP,
			    iamrecursive ? " -r" : "", pflag ? " -p" : "",
			    argv[i], argv[argc - 1]);
			if (verbose_mode)
				fprintf(stderr, "Executing: %s\n", bp);
			if (system(bp))
				++errs;
			(void) xfree(bp);
			continue;
		}
		*src++ = 0;
		if (*src == 0)
			src = ".";
		if ((host = strchr(argv[i], '@')) == NULL) {
			host = argv[i];
			suser = NULL;
		} else {
			*host++ = 0;
			suser = argv[i];
			if (*suser == '\0')
				suser = pwd->pw_name;
			else if (!okname(suser))
				continue;
		}
		host = cleanhostname(host);
		len = strlen(src) + CMDNEEDS + 20;
		bp = xmalloc(len);
		(void) sprintf(bp, "%s -f %s", cmd, src);
		if (do_cmd(host, suser, bp, &remin, &remout, argc) < 0) {
			(void) xfree(bp);
			++errs;
			continue;
		}
		xfree(bp);
		sink(1, argv + argc - 1);
		(void) close(remin);
		remin = remout = -1;
	}
}

void
source(argc, argv)
	int argc;
	char *argv[];
{
	struct stat stb;
	static BUF buffer;
	BUF *bp;
	off_t i;
	int amt, fd, haderr, indx, result;
	char *last, *name, buf[2048];

	for (indx = 0; indx < argc; ++indx) {
		name = argv[indx];
		statbytes = 0;
		if ((fd = open(name, O_RDONLY, 0)) < 0)
			goto syserr;
		if (fstat(fd, &stb) < 0) {
syserr:			run_err("%s: %s", name, strerror(errno));
			goto next;
		}
		switch (stb.st_mode & S_IFMT) {
		case S_IFREG:
			break;
		case S_IFDIR:
			if (iamrecursive) {
				rsource(name, &stb);
				goto next;
			}
			/* FALLTHROUGH */
		default:
			run_err("%s: not a regular file", name);
			goto next;
		}
		if ((last = strrchr(name, '/')) == NULL)
			last = name;
		else
			++last;
		curfile = last;
		if (pflag) {
			/*
			 * Make it compatible with possible future
			 * versions expecting microseconds.
			 */
			(void) sprintf(buf, "T%lu 0 %lu 0\n",
			    (unsigned long) stb.st_mtime,
			    (unsigned long) stb.st_atime);
			(void) atomicio(write, remout, buf, strlen(buf));
			if (response() < 0)
				goto next;
		}
#define	FILEMODEMASK	(S_ISUID|S_ISGID|S_IRWXU|S_IRWXG|S_IRWXO)
		(void) sprintf(buf, "C%04o %lu %s\n",
			     (unsigned int) (stb.st_mode & FILEMODEMASK),
			       (unsigned long) stb.st_size,
			       last);
		if (verbose_mode) {
			fprintf(stderr, "Sending file modes: %s", buf);
			fflush(stderr);
		}
		(void) atomicio(write, remout, buf, strlen(buf));
		if (response() < 0)
			goto next;
		if ((bp = allocbuf(&buffer, fd, 2048)) == NULL) {
next:			(void) close(fd);
			continue;
		}
		if (showprogress) {
			totalbytes = stb.st_size;
			progressmeter(-1);
		}
		/* Keep writing after an error so that we stay sync'd up. */
		for (haderr = i = 0; i < stb.st_size; i += bp->cnt) {
			amt = bp->cnt;
			if (i + amt > stb.st_size)
				amt = stb.st_size - i;
			if (!haderr) {
				result = atomicio(read, fd, bp->buf, amt);
				if (result != amt)
					haderr = result >= 0 ? EIO : errno;
			}
			if (haderr)
				(void) atomicio(write, remout, bp->buf, amt);
			else {
				result = atomicio(write, remout, bp->buf, amt);
				if (result != amt)
					haderr = result >= 0 ? EIO : errno;
				statbytes += result;
			}
		}
		if (showprogress)
			progressmeter(1);

		if (close(fd) < 0 && !haderr)
			haderr = errno;
		if (!haderr)
			(void) atomicio(write, remout, "", 1);
		else
			run_err("%s: %s", name, strerror(haderr));
		(void) response();
	}
}

void
rsource(name, statp)
	char *name;
	struct stat *statp;
{
	DIR *dirp;
	struct dirent *dp;
	char *last, *vect[1], path[1100];

	if (!(dirp = opendir(name))) {
		run_err("%s: %s", name, strerror(errno));
		return;
	}
	last = strrchr(name, '/');
	if (last == 0)
		last = name;
	else
		last++;
	if (pflag) {
		(void) sprintf(path, "T%lu 0 %lu 0\n",
		    (unsigned long) statp->st_mtime,
		    (unsigned long) statp->st_atime);
		(void) atomicio(write, remout, path, strlen(path));
		if (response() < 0) {
			closedir(dirp);
			return;
		}
	}
	(void) sprintf(path, "D%04o %d %.1024s\n",
	    (unsigned int) (statp->st_mode & FILEMODEMASK), 0, last);
	if (verbose_mode)
		fprintf(stderr, "Entering directory: %s", path);
	(void) atomicio(write, remout, path, strlen(path));
	if (response() < 0) {
		closedir(dirp);
		return;
	}
	while ((dp = readdir(dirp))) {
		if (dp->d_ino == 0)
			continue;
		if (!strcmp(dp->d_name, ".") || !strcmp(dp->d_name, ".."))
			continue;
		if (strlen(name) + 1 + strlen(dp->d_name) >= sizeof(path) - 1) {
			run_err("%s/%s: name too long", name, dp->d_name);
			continue;
		}
		(void) sprintf(path, "%s/%s", name, dp->d_name);
		vect[0] = path;
		source(1, vect);
	}
	(void) closedir(dirp);
	(void) atomicio(write, remout, "E\n", 2);
	(void) response();
}

void
sink(argc, argv)
	int argc;
	char *argv[];
{
	static BUF buffer;
	struct stat stb;
	enum {
		YES, NO, DISPLAYED
	} wrerr;
	BUF *bp;
	off_t i, j;
	int amt, count, exists, first, mask, mode, ofd, omode;
	off_t size;
	int setimes, targisdir, wrerrno = 0;
	char ch, *cp, *np, *targ, *why, *vect[1], buf[2048];
	struct utimbuf ut;
	int dummy_usec;

#define	SCREWUP(str)	{ why = str; goto screwup; }

	setimes = targisdir = 0;
	mask = umask(0);
	if (!pflag)
		(void) umask(mask);
	if (argc != 1) {
		run_err("ambiguous target");
		exit(1);
	}
	targ = *argv;
	if (targetshouldbedirectory)
		verifydir(targ);

	(void) atomicio(write, remout, "", 1);
	if (stat(targ, &stb) == 0 && S_ISDIR(stb.st_mode))
		targisdir = 1;
	for (first = 1;; first = 0) {
		cp = buf;
		if (atomicio(read, remin, cp, 1) <= 0)
			return;
		if (*cp++ == '\n')
			SCREWUP("unexpected <newline>");
		do {
			if (atomicio(read, remin, &ch, sizeof(ch)) != sizeof(ch))
				SCREWUP("lost connection");
			*cp++ = ch;
		} while (cp < &buf[sizeof(buf) - 1] && ch != '\n');
		*cp = 0;

		if (buf[0] == '\01' || buf[0] == '\02') {
			if (iamremote == 0)
				(void) atomicio(write, STDERR_FILENO,
					     buf + 1, strlen(buf + 1));
			if (buf[0] == '\02')
				exit(1);
			++errs;
			continue;
		}
		if (buf[0] == 'E') {
			(void) atomicio(write, remout, "", 1);
			return;
		}
		if (ch == '\n')
			*--cp = 0;

#define getnum(t) (t) = 0; \
  while (*cp >= '0' && *cp <= '9') (t) = (t) * 10 + (*cp++ - '0');
		cp = buf;
		if (*cp == 'T') {
			setimes++;
			cp++;
			getnum(ut.modtime);
			if (*cp++ != ' ')
				SCREWUP("mtime.sec not delimited");
			getnum(dummy_usec);
			if (*cp++ != ' ')
				SCREWUP("mtime.usec not delimited");
			getnum(ut.actime);
			if (*cp++ != ' ')
				SCREWUP("atime.sec not delimited");
			getnum(dummy_usec);
			if (*cp++ != '\0')
				SCREWUP("atime.usec not delimited");
			(void) atomicio(write, remout, "", 1);
			continue;
		}
		if (*cp != 'C' && *cp != 'D') {
			/*
			 * Check for the case "rcp remote:foo\* local:bar".
			 * In this case, the line "No match." can be returned
			 * by the shell before the rcp command on the remote is
			 * executed so the ^Aerror_message convention isn't
			 * followed.
			 */
			if (first) {
				run_err("%s", cp);
				exit(1);
			}
			SCREWUP("expected control record");
		}
		mode = 0;
		for (++cp; cp < buf + 5; cp++) {
			if (*cp < '0' || *cp > '7')
				SCREWUP("bad mode");
			mode = (mode << 3) | (*cp - '0');
		}
		if (*cp++ != ' ')
			SCREWUP("mode not delimited");

		for (size = 0; *cp >= '0' && *cp <= '9';)
			size = size * 10 + (*cp++ - '0');
		if (*cp++ != ' ')
			SCREWUP("size not delimited");
		if (targisdir) {
			static char *namebuf;
			static int cursize;
			size_t need;

			need = strlen(targ) + strlen(cp) + 250;
			if (need > cursize)
				namebuf = xmalloc(need);
			(void) sprintf(namebuf, "%s%s%s", targ,
			    *targ ? "/" : "", cp);
			np = namebuf;
		} else
			np = targ;
		curfile = cp;
		exists = stat(np, &stb) == 0;
		if (buf[0] == 'D') {
			int mod_flag = pflag;
			if (exists) {
				if (!S_ISDIR(stb.st_mode)) {
					errno = ENOTDIR;
					goto bad;
				}
				if (pflag)
					(void) chmod(np, mode);
			} else {
				/* Handle copying from a read-only
				   directory */
				mod_flag = 1;
				if (mkdir(np, mode | S_IRWXU) < 0)
					goto bad;
			}
			vect[0] = np;
			sink(1, vect);
			if (setimes) {
				setimes = 0;
				if (utime(np, &ut) < 0)
					run_err("%s: set times: %s",
						np, strerror(errno));
			}
			if (mod_flag)
				(void) chmod(np, mode);
			continue;
		}
		omode = mode;
		mode |= S_IWRITE;
		if ((ofd = open(np, O_WRONLY | O_CREAT | O_TRUNC, mode)) < 0) {
bad:			run_err("%s: %s", np, strerror(errno));
			continue;
		}
		(void) atomicio(write, remout, "", 1);
		if ((bp = allocbuf(&buffer, ofd, 4096)) == NULL) {
			(void) close(ofd);
			continue;
		}
		cp = bp->buf;
		wrerr = NO;

		if (showprogress) {
			totalbytes = size;
			progressmeter(-1);
		}
		statbytes = 0;
		for (count = i = 0; i < size; i += 4096) {
			amt = 4096;
			if (i + amt > size)
				amt = size - i;
			count += amt;
			do {
				j = atomicio(read, remin, cp, amt);
				if (j <= 0) {
					run_err("%s", j ? strerror(errno) :
						"dropped connection");
					exit(1);
				}
				amt -= j;
				cp += j;
				statbytes += j;
			} while (amt > 0);
			if (count == bp->cnt) {
				/* Keep reading so we stay sync'd up. */
				if (wrerr == NO) {
					j = atomicio(write, ofd, bp->buf, count);
					if (j != count) {
						wrerr = YES;
						wrerrno = j >= 0 ? EIO : errno;
					}
				}
				count = 0;
				cp = bp->buf;
			}
		}
		if (showprogress)
			progressmeter(1);
		if (count != 0 && wrerr == NO &&
		    (j = atomicio(write, ofd, bp->buf, count)) != count) {
			wrerr = YES;
			wrerrno = j >= 0 ? EIO : errno;
		}
#if 0
		if (ftruncate(ofd, size)) {
			run_err("%s: truncate: %s", np, strerror(errno));
			wrerr = DISPLAYED;
		}
#endif
		if (pflag) {
			if (exists || omode != mode)
				if (fchmod(ofd, omode))
					run_err("%s: set mode: %s",
						np, strerror(errno));
		} else {
			if (!exists && omode != mode)
				if (fchmod(ofd, omode & ~mask))
					run_err("%s: set mode: %s",
						np, strerror(errno));
		}
		if (close(ofd) == -1) {
			wrerr = YES;
			wrerrno = errno;
		}
		(void) response();
		if (setimes && wrerr == NO) {
			setimes = 0;
			if (utime(np, &ut) < 0) {
				run_err("%s: set times: %s",
					np, strerror(errno));
				wrerr = DISPLAYED;
			}
		}
		switch (wrerr) {
		case YES:
			run_err("%s: %s", np, strerror(wrerrno));
			break;
		case NO:
			(void) atomicio(write, remout, "", 1);
			break;
		case DISPLAYED:
			break;
		}
	}
screwup:
	run_err("protocol error: %s", why);
	exit(1);
}

int
response()
{
	char ch, *cp, resp, rbuf[2048];

	if (atomicio(read, remin, &resp, sizeof(resp)) != sizeof(resp))
		lostconn(0);

	cp = rbuf;
	switch (resp) {
	case 0:		/* ok */
		return (0);
	default:
		*cp++ = resp;
		/* FALLTHROUGH */
	case 1:		/* error, followed by error msg */
	case 2:		/* fatal error, "" */
		do {
			if (atomicio(read, remin, &ch, sizeof(ch)) != sizeof(ch))
				lostconn(0);
			*cp++ = ch;
		} while (cp < &rbuf[sizeof(rbuf) - 1] && ch != '\n');

		if (!iamremote)
			(void) atomicio(write, STDERR_FILENO, rbuf, cp - rbuf);
		++errs;
		if (resp == 1)
			return (-1);
		exit(1);
	}
	/* NOTREACHED */
}

void
usage()
{
	(void) fprintf(stderr, "usage: scp "
	    "[-pqrvC46] [-S ssh] [-P port] [-c cipher] [-i identity] f1 f2; or:\n"
	    "       scp [options] f1 ... fn directory\n");
	exit(1);
}

void
run_err(const char *fmt,...)
{
	static FILE *fp;
	va_list ap;

	++errs;
	if (fp == NULL && !(fp = fdopen(remout, "w")))
		return;
	(void) fprintf(fp, "%c", 0x01);
	(void) fprintf(fp, "scp: ");
	va_start(ap, fmt);
	(void) vfprintf(fp, fmt, ap);
	va_end(ap);
	(void) fprintf(fp, "\n");
	(void) fflush(fp);

	if (!iamremote) {
		va_start(ap, fmt);
		vfprintf(stderr, fmt, ap);
		va_end(ap);
		fprintf(stderr, "\n");
	}
}

char *
colon(cp)
	char *cp;
{
	int flag = 0;

	if (*cp == ':')		/* Leading colon is part of file name. */
		return (0);
	if (*cp == '[')
		flag = 1;

	for (; *cp; ++cp) {
		if (*cp == '@' && *(cp+1) == '[')
			flag = 1;
		if (*cp == ']' && *(cp+1) == ':' && flag)
			return (cp+1);
		if (*cp == ':' && !flag)
			return (cp);
		if (*cp == '/')
			return (0);
	}
	return (0);
}

void
verifydir(cp)
	char *cp;
{
	struct stat stb;

	if (!stat(cp, &stb)) {
		if (S_ISDIR(stb.st_mode))
			return;
		errno = ENOTDIR;
	}
	run_err("%s: %s", cp, strerror(errno));
	exit(1);
}

int
okname(cp0)
	char *cp0;
{
	int c;
	char *cp;

	cp = cp0;
	do {
		c = *cp;
		if (c & 0200)
			goto bad;
		if (!isalpha(c) && !isdigit(c) && c != '_' && c != '-')
			goto bad;
	} while (*++cp);
	return (1);

bad:	fprintf(stderr, "%s: invalid user name\n", cp0);
	return (0);
}

BUF *
allocbuf(bp, fd, blksize)
	BUF *bp;
	int fd, blksize;
{
	size_t size;
	struct stat stb;

	if (fstat(fd, &stb) < 0) {
		run_err("fstat: %s", strerror(errno));
		return (0);
	}
	if (stb.st_blksize == 0)
		size = blksize;
	else
		size = blksize + (stb.st_blksize - blksize % stb.st_blksize) %
		    stb.st_blksize;
	if (bp->cnt >= size)
		return (bp);
	if (bp->buf == NULL)
		bp->buf = xmalloc(size);
	else
		bp->buf = xrealloc(bp->buf, size);
	bp->cnt = size;
	return (bp);
}

void
lostconn(signo)
	int signo;
{
	if (!iamremote)
		fprintf(stderr, "lost connection\n");
	exit(1);
}


void
alarmtimer(int wait)
{
	struct itimerval itv;

	itv.it_value.tv_sec = wait;
	itv.it_value.tv_usec = 0;
	itv.it_interval = itv.it_value;
	setitimer(ITIMER_REAL, &itv, NULL);
}

void
updateprogressmeter(int ignore)
{
	int save_errno = errno;

	progressmeter(0);
	errno = save_errno;
}

int
foregroundproc()
{
	static pid_t pgrp = -1;
	int ctty_pgrp;

	if (pgrp == -1)
		pgrp = getpgrp();

#ifdef HAVE_CYGWIN
	/*
	 * Cygwin only supports tcgetpgrp() for getting the controlling tty
         * currently.
	 */
	return ((ctty_pgrp = tcgetpgrp(STDOUT_FILENO)) != -1 &&
		ctty_pgrp == pgrp);
#else
	return ((ioctl(STDOUT_FILENO, TIOCGPGRP, &ctty_pgrp) != -1 &&
		 ctty_pgrp == pgrp));
#endif
}

void
progressmeter(int flag)
{
	static const char prefixes[] = " KMGTP";
	static struct timeval lastupdate;
	static off_t lastsize;
	struct timeval now, td, wait;
	off_t cursize, abbrevsize;
	double elapsed;
	int ratio, barlength, i, remaining;
	char buf[256];

	if (flag == -1) {
		(void) gettimeofday(&start, (struct timezone *) 0);
		lastupdate = start;
		lastsize = 0;
	}
	if (foregroundproc() == 0)
		return;

	(void) gettimeofday(&now, (struct timezone *) 0);
	cursize = statbytes;
	if (totalbytes != 0) {
		ratio = 100.0 * cursize / totalbytes;
		ratio = MAX(ratio, 0);
		ratio = MIN(ratio, 100);
	} else
		ratio = 100;

	snprintf(buf, sizeof(buf), "\r%-20.20s %3d%% ", curfile, ratio);

	barlength = getttywidth() - 51;
	barlength = (barlength <= MAX_BARLENGTH)?barlength:MAX_BARLENGTH;
	if (barlength > 0) {
		i = barlength * ratio / 100;
		snprintf(buf + strlen(buf), sizeof(buf) - strlen(buf),
			 "|%.*s%*s|", i, BAR, barlength - i, "");
	}
	i = 0;
	abbrevsize = cursize;
	while (abbrevsize >= 100000 && i < sizeof(prefixes)) {
		i++;
		abbrevsize >>= 10;
	}
	snprintf(buf + strlen(buf), sizeof(buf) - strlen(buf), " %5d %c%c ",
	     (int) abbrevsize, prefixes[i], prefixes[i] == ' ' ? ' ' :
		 'B');

	timersub(&now, &lastupdate, &wait);
	if (cursize > lastsize) {
		lastupdate = now;
		lastsize = cursize;
		if (wait.tv_sec >= STALLTIME) {
			start.tv_sec += wait.tv_sec;
			start.tv_usec += wait.tv_usec;
		}
		wait.tv_sec = 0;
	}
	timersub(&now, &start, &td);
	elapsed = td.tv_sec + (td.tv_usec / 1000000.0);

	if (statbytes <= 0 || elapsed <= 0.0 || cursize > totalbytes) {
		snprintf(buf + strlen(buf), sizeof(buf) - strlen(buf),
			 "   --:-- ETA");
	} else if (wait.tv_sec >= STALLTIME) {
		snprintf(buf + strlen(buf), sizeof(buf) - strlen(buf),
			 " - stalled -");
	} else {
		if (flag != 1)
			remaining =
			    (int)(totalbytes / (statbytes / elapsed) - elapsed);
		else
			remaining = elapsed;

		i = remaining / 3600;
		if (i)
			snprintf(buf + strlen(buf), sizeof(buf) - strlen(buf),
			    "%2d:", i);
		else
			snprintf(buf + strlen(buf), sizeof(buf) - strlen(buf),
			    "   ");
		i = remaining % 3600;
		snprintf(buf + strlen(buf), sizeof(buf) - strlen(buf),
		    "%02d:%02d%s", i / 60, i % 60,
		    (flag != 1) ? " ETA" : "    ");
	}
	atomicio(write, fileno(stdout), buf, strlen(buf));

	if (flag == -1) {
		struct sigaction sa;
		sa.sa_handler = updateprogressmeter;
		sigemptyset((sigset_t *)&sa.sa_mask);
#ifdef SA_RESTART
		sa.sa_flags = SA_RESTART;
#endif
		sigaction(SIGALRM, &sa, NULL);
		alarmtimer(1);
	} else if (flag == 1) {
		alarmtimer(0);
		atomicio(write, fileno(stdout), "\n", 1);
		statbytes = 0;
	}
}

int
getttywidth(void)
{
	struct winsize winsize;

	if (ioctl(fileno(stdout), TIOCGWINSZ, &winsize) != -1)
		return (winsize.ws_col ? winsize.ws_col : 80);
	else
		return (80);
}