Return to mktemp.c CVS log

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new attempt to sync with kristaps up to Sun Feb 17 2019

339cf5998c0c022623cd68de50722b6c14543952 Push "error trail" further into code.

baf58ce5fe1bc6ce431b3b0ac8264b83ae8c7d02 Document all arguments.  Add
common -av usage.  Remove bits about not supporting anything but
files/dirs.

821a811a8c80e52fb56b241fc65a16cae1b4fb2c Disambiguate as prodded by deraadt@

6c4475b8f226e9031ec0ec1b3f14f7d347132c87 Add -h to usage string

4d344ae6156873b44c95de0c1ed629e637c2d7ab Clarify error message
language, use service name instead of port, specify that the socket is
SOCK_STREAM.  From deraadt@.  Tweaked for lowercase messages.

f3ec049e76257fc96bcdc872f1d3b967b98f3eb6 In consideration to benno@'s
comments, let the mktemp functions propogate an errno handled by the
caller.  Also keep the original line lengths.  While in mktemp.c, make
some defines into an enum.

e116c2bd00e634b56e4276120135915ceaa31cf2 Put the FSM of the sender
into its own function.  Put dry_run ack and end of phase ack into the
send buffer too, further reducing the possibility of deadlock.

c7745aa4c7394ca89d841f8ee76782256d694340 Make the sender write loop be
fully non-blocking.  This frees us of deadlocking the protocol because
the sender will always be able to pull down data.

93c7b4843e80aeac2ec6ae6ffc395df4deaf4a31 Remove "yoda" notation to be
more in tune with OpenBSD.  Most found by deraadt@.

/*	$OpenBSD: mktemp.c,v 1.7 2019/02/18 22:47:34 benno Exp $ */
/*
 * Copyright (c) 1996-1998, 2008 Theo de Raadt
 * Copyright (c) 1997, 2008-2009 Todd C. Miller
 * Copyright (c) 2019 Florian Obser <florian@openbsd.org>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <sys/types.h>
#include <sys/stat.h>
#include <sys/socket.h>
#include <sys/un.h>

#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <unistd.h>

#include "extern.h"

/*
 * The type of temporary files we can create.
 */
enum	tmpmode {
	MKTEMP_NAME,
	MKTEMP_FILE,
	MKTEMP_DIR,
	MKTEMP_LINK,
	MKTEMP_FIFO,
	MKTEMP_NOD,
	MKTEMP_SOCK
};

/*
 * Characters we'll use for replacement in the template string.
 */
#define TEMPCHARS	"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"
#define NUM_CHARS	(sizeof(TEMPCHARS) - 1)

/*
 * The number of template replacement values (foo.XXXXXX = 6) that we
 * require as a minimum for the filename.
 */
#define MIN_X		6

/*
 * The only flags we'll accept for creation of the temporary file.
 */
#define MKOTEMP_FLAGS	(O_APPEND | O_CLOEXEC | O_DSYNC | O_RSYNC | O_SYNC)

#ifndef nitems
#define nitems(_a)	(sizeof((_a)) / sizeof((_a)[0]))
#endif

/*
 * Adapted from libc/stdio/mktemp.c.
 */
static int
mktemp_internalat(int pfd, char *path, int slen, enum tmpmode mode,
	int flags, const char *link, mode_t dev_type, dev_t dev)
{
	char 		*start, *cp, *ep;
	const char 	 tempchars[] = TEMPCHARS;
	unsigned int 	 tries;
	struct stat 	 sb;
	struct sockaddr_un sun;
	size_t 		 len;
	int 		 fd, saved_errno;

	len = strlen(path);
	if (len < MIN_X || slen < 0 || (size_t)slen > len - MIN_X) {
		errno = EINVAL;
		return(-1);
	}
	ep = path + len - slen;

	for (start = ep; start > path && start[-1] == 'X'; start--)
		/* continue */ ;

	if (ep - start < MIN_X) {
		errno = EINVAL;
		return(-1);
	}

	if (flags & ~MKOTEMP_FLAGS) {
		errno = EINVAL;
		return(-1);
	}
	flags |= O_CREAT | O_EXCL | O_RDWR;

	tries = INT_MAX;
	do {
		cp = start;
		do {
			unsigned short rbuf[16];
			unsigned int i;

			/*
			 * Avoid lots of arc4random() calls by using
			 * a buffer sized for up to 16 Xs at a time.
			 */
			arc4random_buf(rbuf, sizeof(rbuf));
			for (i = 0; i < nitems(rbuf) && cp != ep; i++)
				*cp++ = tempchars[rbuf[i] % NUM_CHARS];
		} while (cp != ep);

		switch (mode) {
		case MKTEMP_NAME:
			if (fstatat(pfd, path, &sb, AT_SYMLINK_NOFOLLOW) != 0)
				return(errno == ENOENT ? 0 : -1);
			break;
		case MKTEMP_FILE:
			fd = openat(pfd, path, flags, S_IRUSR|S_IWUSR);
			if (fd != -1 || errno != EEXIST)
				return(fd);
			break;
		case MKTEMP_DIR:
			if (mkdirat(pfd, path, S_IRUSR|S_IWUSR|S_IXUSR) == 0)
				return(0);
			if (errno != EEXIST)
				return(-1);
			break;
		case MKTEMP_LINK:
			if (symlinkat(link, pfd, path) == 0)
				return(0);
			else if (errno != EEXIST)
				return(-1);
			break;
		case MKTEMP_FIFO:
			if (mkfifoat(pfd, path, S_IRUSR|S_IWUSR) == 0)
				return(0);
			else if (errno != EEXIST)
				return(-1);
			break;
		case MKTEMP_NOD:
			if (!(dev_type == S_IFCHR || dev_type == S_IFBLK)) {
				errno = EINVAL;
				return(-1);
			}
			if (mknodat(pfd, path, S_IRUSR|S_IWUSR|dev_type, dev)
			    == 0)
				return(0);
			else if (errno != EEXIST)
				return(-1);
			break;
		case MKTEMP_SOCK:
			memset(&sun, 0, sizeof(sun));
			sun.sun_family = AF_UNIX;
			if ((len = strlcpy(sun.sun_path, link,
			    sizeof(sun.sun_path))) >= sizeof(sun.sun_path)) {
				errno = EINVAL;
				return(-1);
			}
			if (sun.sun_path[len] != '/') {
				if (strlcat(sun.sun_path, "/",
				    sizeof(sun.sun_path)) >=
				    sizeof(sun.sun_path)) {
					errno = EINVAL;
					return(-1);
				}
			}
			if (strlcat(sun.sun_path, path, sizeof(sun.sun_path)) >=
			    sizeof(sun.sun_path)) {
				errno = EINVAL;
				return(-1);
			}
			if ((fd = socket(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC |
			    SOCK_NONBLOCK, 0)) == -1)
				return -1;
			if (bind(fd, (struct sockaddr *)&sun, sizeof(sun)) ==
			    0) {
				close(fd);
				return(0);
			} else if (errno != EEXIST) {
					saved_errno = errno;
					close(fd);
					errno = saved_errno;
					return -1;
			}
			close(fd);
			break;
		}
	} while (--tries);

	errno = EEXIST;
	return(-1);
}

/*
 * A combination of mkstemp(3) and openat(2).
 * On success returns a file descriptor and trailing Xs are overwritten in
 * path to create a unique file name.
 * Returns -1 on failure and sets errno.
 */
int
mkstempat(int fd, char *path)
{
	return mktemp_internalat(fd, path, 0, MKTEMP_FILE, 0, NULL, 0, 0);
}

/*
 * A combination of mkstemp(3) and symlinkat(2).
 * On success returns path with trailing Xs overwritten to create a unique
 * file name.
 * Returns NULL on failure and sets errno.
 */
char *
mkstemplinkat(char *link, int fd, char *path)
{

	if (mktemp_internalat(fd, path, 0, MKTEMP_LINK, 0, link, 0, 0) == -1)
		return NULL;
	return path;
}

/*
 * A combination of mkstemp(3) and mkfifoat(2).
 * On success returns path with trailing Xs overwritten to create a unique
 * file name.
 * Returns NULL on failure and sets errno.
 */
char *
mkstempfifoat(int fd, char *path)
{

	if (mktemp_internalat(fd, path, 0, MKTEMP_FIFO, 0, NULL, 0, 0) == -1)
		return NULL;
	return path;
}

/*
 * A combination of mkstemp(3) and mknodat(2).
 * On success returns path with trailing Xs overwritten to create a unique
 * file name.
 * Returns NULL on failure and sets errno.
 */
char *
mkstempnodat(int fd, char *path, mode_t mode, dev_t dev)
{

	if (mktemp_internalat(fd, path, 0,
	    MKTEMP_NOD, 0, NULL, mode, dev) == -1)
		return NULL;
	return path;
}

/*
 * A combination of mkstemp(3) and bind(2) on a unix domain socket.
 * On success returns path with trailing Xs overwritten to create a unique
 * file name.
 * Returns NULL on failure and sets errno.
 */
char *
mkstempsock(const char *root, char *path)
{

	if (mktemp_internalat(0, path, 0, MKTEMP_SOCK, 0, root, 0, 0) == -1)
		return NULL;
	return path;
}

/*
 * Turn path into a suitable template for mkstemp*at functions and
 * place it into the newly allocated string returned in ret.
 * The caller must free ret.
 * Returns -1 on failure or number of characters output to ret
 * (excluding the final '\0').
 */
int
mktemplate(struct sess *sess, char **ret, const char *path, int recursive)
{
	int		 n, dirlen;
	const char	*cp;

	if (recursive && (cp = strrchr(path, '/')) != NULL) {
		dirlen = cp - path;
		n = asprintf(ret, "%.*s/.%s.XXXXXXXXXX",
			dirlen, path, path + dirlen + 1);
		if (n < 0) {
			ERR(sess, "asprintf");
			*ret = NULL;
		}
	} else if ((n = asprintf(ret, ".%s.XXXXXXXXXX", path)) < 0) {
		ERR(sess, "asprintf");
		*ret = NULL;
	}

	return n;
}