exf.c

早期freebsd实现

	/*
	 * Close the previous file; if that fails, close the new one
	 * and run for the border.
	 */
	if (sp->ep != NULL && file_end(sp, sp->ep, force)) {
		(void)file_end(sp, ep, 1);
		goto err;
	}

	/*
	 * 4.4BSD supports locking in the open call, other systems don't.
	 * Since the user can't interrupt us between the open and here,
	 * it's a don't care.
	 *
	 * !!!
	 * We need to distinguish a lock not being available for the file
	 * from the file system not supporting locking.  Assume that EAGAIN
	 * or EWOULDBLOCK is the former.  There isn't a portable way to do
	 * this.
	 *
	 * XXX
	 * The locking is flock(2) style, not fcntl(2).  The latter is known
	 * to fail badly on some systems, and its only advantage is that it
	 * occasionally works over NFS.
	 */
	if (flock(ep->db->fd(ep->db), LOCK_EX | LOCK_NB))
		if (errno == EAGAIN || errno == EWOULDBLOCK) {
			msgq(sp, M_INFO,
			    "%s already locked, session is read-only", oname);
			F_SET(frp, FR_RDONLY);
		} else
			msgq(sp, M_VINFO, "%s cannot be locked", oname);

	/*
	 * Set the previous file pointer and the alternate file name to be
	 * the file we're about to discard.
	 *
	 * !!!
	 * If the current file was a temporary file, the call to file_end()
	 * unlinked it and free'd the name.  So, there is no previous file,
	 * and there is no alternate file name.  This matches historical
	 * practice, although in historical vi it could only happen as the
	 * result of the initial command, i.e. if vi was execute without a
	 * file name.
	 */
	if (sp->frp != NULL) {
		p = FILENAME(sp->frp);
		if (p == NULL)
			sp->p_frp = NULL;
		else
			sp->p_frp = sp->frp;
		set_alt_name(sp, p);
	}

	/* The new file has now been officially edited. */
	F_SET(frp, FR_EDITED);

	/* Switch... */
	++ep->refcnt;
	sp->ep = ep;
	sp->frp = frp;
	return (0);

err:	if (frp->tname != NULL) {
		(void)unlink(frp->tname);
		free(frp->tname);
		frp->tname = NULL;
	}
	if (ep->rcv_path != NULL) {
		free(ep->rcv_path);
		ep->rcv_path = NULL;
	}
	FREE(ep, sizeof(EXF));
	return (1);
}

/*
 * file_end --
 *	Stop editing a file.
 */
int
file_end(sp, ep, force)
	SCR *sp;
	EXF *ep;
	int force;
{
	FREF *frp;

	/*
	 *
	 * sp->ep MAY NOT BE THE SAME AS THE ARGUMENT ep, SO DON'T USE IT!
	 *
	 * Save the cursor location.
	 *
	 * XXX
	 * It would be cleaner to do this somewhere else, but by the time
	 * ex or vi knows that we're changing files it's already happened.
	 */
	frp = sp->frp;
	frp->lno = sp->lno;
	frp->cno = sp->cno;
	F_SET(frp, FR_CURSORSET);

	/* If multiply referenced, just decrement the count and return. */
	if (--ep->refcnt != 0)
		return (0);

	/* Close the db structure. */
	if (ep->db->close != NULL && ep->db->close(ep->db) && !force) {
		msgq(sp, M_ERR,
		    "%s: close: %s", FILENAME(frp), strerror(errno));
		++ep->refcnt;
		return (1);
	}

	/* COMMITTED TO THE CLOSE.  THERE'S NO GOING BACK... */

	/* Stop logging. */
	(void)log_end(sp, ep);

	/* Free up any marks. */
	mark_end(sp, ep);

	/*
	 * Delete the recovery files, close the open descriptor,
	 * free recovery memory.
	 */
	if (!F_ISSET(ep, F_RCV_NORM)) {
		if (ep->rcv_path != NULL && unlink(ep->rcv_path))
			msgq(sp, M_ERR,
			    "%s: remove: %s", ep->rcv_path, strerror(errno));
		if (ep->rcv_mpath != NULL && unlink(ep->rcv_mpath))
			msgq(sp, M_ERR,
			    "%s: remove: %s", ep->rcv_mpath, strerror(errno));
	}
	if (ep->rcv_fd != -1)
		(void)close(ep->rcv_fd);
	if (ep->rcv_path != NULL)
		free(ep->rcv_path);
	if (ep->rcv_mpath != NULL)
		free(ep->rcv_mpath);

	/*
	 * Unlink any temporary file, file name.  We also turn on the
	 * ignore bit at this point, because it was a "created" file,
	 * not an argument file.
	 */
	if (frp->tname != NULL) {
		if (unlink(frp->tname))
			msgq(sp, M_ERR,
			    "%s: remove: %s", frp->tname, strerror(errno));
		free(frp->tname);
		frp->tname = NULL;

		if (frp->name == NULL && frp->cname == NULL)
			F_SET(frp, FR_IGNORE);
	}
	/* Free the EXF structure. */
	FREE(ep, sizeof(EXF));
	return (0);
}

/*
 * file_write --
 *	Write the file to disk.  Historic vi had fairly convoluted
 *	semantics for whether or not writes would happen.  That's
 *	why all the flags.
 */
int
file_write(sp, ep, fm, tm, name, flags)
	SCR *sp;
	EXF *ep;
	MARK *fm, *tm;
	char *name;
	int flags;
{
	struct stat sb;
	FILE *fp;
	FREF *frp;
	MARK from, to;
	u_long nlno, nch;
	int btear, fd, itear, oflags, rval;
	char *msg;

	/*
	 * Don't permit writing to temporary files.  The problem is that
	 * if it's a temp file, and the user does ":wq", we write and quit,
	 * unlinking the temporary file.  Not what the user had in mind
	 * at all.  This test cannot be forced.
	 */
	frp = sp->frp;
	if (name == NULL && frp->cname == NULL && frp->name == NULL) {
		msgq(sp, M_ERR, "No filename to which to write.");
		return (1);
	}

	/* Can't write files marked read-only, unless forced. */
	if (!LF_ISSET(FS_FORCE) &&
	    name == NULL && F_ISSET(frp, FR_RDONLY)) {
		if (LF_ISSET(FS_POSSIBLE))
			msgq(sp, M_ERR,
			    "Read-only file, not written; use ! to override.");
		else
			msgq(sp, M_ERR,
			    "Read-only file, not written.");
		return (1);
	}

	/* If not forced, not appending, and "writeany" not set ... */
	if (!LF_ISSET(FS_FORCE | FS_APPEND) && !O_ISSET(sp, O_WRITEANY)) {
		/* Don't overwrite anything but the original file. */
		if (name != NULL) {
			if (!stat(name, &sb))
				goto exists;
		} else if (frp->cname != NULL &&
		    !F_ISSET(frp, FR_CHANGEWRITE) && !stat(frp->cname, &sb)) {
			name = frp->cname;
exists:			if (LF_ISSET(FS_POSSIBLE))
				msgq(sp, M_ERR,
		"%s exists, not written; use ! to override.", name);
			else
				msgq(sp, M_ERR,
				    "%s exists, not written.", name);
			return (1);
		}

		/*
		 * Don't write part of any existing file.  Only test for the
		 * original file, the previous test catches anything else.
		 */
		if (!LF_ISSET(FS_ALL) && name == NULL &&
		    frp->cname == NULL && !stat(frp->name, &sb)) {
			if (LF_ISSET(FS_POSSIBLE))
				msgq(sp, M_ERR,
				    "Use ! to write a partial file.");
			else
				msgq(sp, M_ERR, "Partial file, not written.");
			return (1);
		}
	}

	/*
	 * Figure out if the file already exists -- if it doesn't, we display
	 * the "new file" message.  The stat might not be necessary, but we
	 * just repeat it because it's easier than hacking the previous tests.
	 * The information is only used for the user message and modification
	 * time test, so we can ignore the obvious race condition.
	 *
	 * If the user is overwriting a file other than the original file, and
	 * O_WRITEANY was what got us here (neither force nor append was set),
	 * display the "existing file" messsage.  Since the FR_CHANGEWRITE flag
	 * is set on a successful write, the message only appears once when the
	 * user changes a file name.  This is historic practice.
	 *
	 * One final test.  If we're not forcing or appending, and we have a
	 * saved modification time, stop the user if it's been written since
	 * we last edited or wrote it, and make them force it.
	 */
	if (stat(name == NULL ? FILENAME(frp) : name, &sb))
		msg = ": new file";
	else {
		msg = "";
		if (!LF_ISSET(FS_FORCE | FS_APPEND)) {
			if (frp->mtime && sb.st_mtime > frp->mtime) {
				msgq(sp, M_ERR,
			"%s: file modified more recently than this copy%s.",
				    name == NULL ? frp->name : name,
				    LF_ISSET(FS_POSSIBLE) ?
				    "; use ! to override" : "");
				return (1);
			}
			if (name != NULL ||
			    !F_ISSET(frp, FR_CHANGEWRITE) && frp->cname != NULL)
				msg = ": existing file";
		}
	}

	/* We no longer care where the name came from. */
	if (name == NULL)
		name = FILENAME(frp);

	/* Set flags to either append or truncate. */
	oflags = O_CREAT | O_WRONLY;
	if (LF_ISSET(FS_APPEND))
		oflags |= O_APPEND;
	else
		oflags |= O_TRUNC;

	/* Open the file. */
	if ((fd = open(name, oflags, DEFFILEMODE)) < 0) {
		msgq(sp, M_SYSERR, name);
		return (1);
	}

	/* Use stdio for buffering. */
	if ((fp = fdopen(fd, "w")) == NULL) {
		(void)close(fd);
		msgq(sp, M_SYSERR, name);
		return (1);
	}

	/* Build fake addresses, if necessary. */
	if (fm == NULL) {
		from.lno = 1;
		from.cno = 0;
		fm = &from;
		if (file_lline(sp, ep, &to.lno))
			return (1);
		to.cno = 0;
		tm = &to;
	}

	/* Write the file, allowing interrupts. */
	btear = F_ISSET(sp, S_EXSILENT) ? 0 : !busy_on(sp, "Writing...");
	itear = !intr_init(sp);
	rval = ex_writefp(sp, ep, name, fp, fm, tm, &nlno, &nch);
	if (btear)
		busy_off(sp);
	if (itear)
		intr_end(sp);

	/*
	 * Save the new last modification time -- even if the write fails
	 * we re-init the time.  That way the user can clean up the disk
	 * and rewrite without having to force it.
	 */
	frp->mtime = stat(name, &sb) ? 0 : sb.st_mtime;

	/* If the write failed, complain loudly. */
	if (rval) {
		if (!LF_ISSET(FS_APPEND))
			msgq(sp, M_ERR, "%s: WARNING: file truncated!", name);
		return (1);
	}

	/*
	 * Once we've actually written the file, it doesn't matter that the
	 * file name was changed -- if it was, we've already whacked it.
	 */
	F_SET(frp, FR_CHANGEWRITE);

	/* If wrote the entire file, clear the modified bit. */
	if (LF_ISSET(FS_ALL))
		F_CLR(ep, F_MODIFIED);

	msgq(sp, M_INFO, "%s%s: %lu line%s, %lu characters.",
	    name, msg, nlno, nlno == 1 ? "" : "s", nch);

	return (0);
}