/* RCS stream editor */

/******************************************************************************
 *                       edits the input file according to a
 *                       script from stdin, generated by diff -n
 *                       performs keyword expansion
 ******************************************************************************
 */

/* Copyright 1982, 1988, 1989 Walter Tichy
   Copyright 1990, 1991, 1992, 1993, 1994, 1995 Paul Eggert
   Distributed under license by the Free Software Foundation, Inc.

This file is part of RCS.

RCS is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.

RCS is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with RCS; see the file COPYING.
If not, write to the Free Software Foundation,
59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.

Report problems and direct all questions to:

    rcs-bugs@cs.purdue.edu

*/

/*
 * $Log: rcsedit.c,v $
 * Revision 5.19  1995/06/16 06:19:24  eggert
 * Update FSF address.
 *
 * Revision 5.18  1995/06/01 16:23:43  eggert
 * (dirtpname): No longer external.
 * (do_link): Simplify logic.
 * (finisheditline, finishedit): Replace Iseek/Itell with what they stand for.
 * (fopen_update_truncate): Replace `#if' with `if'.
 * (keyreplace, makedirtemp): dirlen(x) -> basefilename(x)-x.
 *
 * (edit_string): Fix bug: if !large_memory, a bogus trailing `@' was output
 * at the end of incomplete lines.
 *
 * (keyreplace): Do not assume that seeking backwards
 * at the start of a file will fail; on some systems it succeeds.
 * Convert C- and Pascal-style comment starts to ` *' in comment leader.
 *
 * (rcswriteopen): Use fdSafer to get safer file descriptor.
 * Open RCS file with FOPEN_RB.
 *
 * (chnamemod): Work around bad_NFS_rename bug; don't ignore un_link result.
 * Fall back on chmod if fchmod fails, since it might be ENOSYS.
 *
 * (aflush): Move to rcslex.c.
 *
 * Revision 5.17  1994/03/20 04:52:58  eggert
 * Normally calculate the $Log prefix from context, not from RCS file.
 * Move setmtime here from rcsutil.c.  Add ORCSerror.  Remove lint.
 *
 * Revision 5.16  1993/11/03 17:42:27  eggert
 * Add -z.  Add Name keyword.  If bad_unlink, ignore errno when unlink fails.
 * Escape white space, $, and \ in keyword string file names.
 * Don't output 2 spaces between date and time after Log.
 *
 * Revision 5.15  1992/07/28  16:12:44  eggert
 * Some hosts have readlink but not ELOOP.  Avoid `unsigned'.
 * Preserve dates more systematically.  Statement macro names now end in _.
 *
 * Revision 5.14  1992/02/17  23:02:24  eggert
 * Add -T support.
 *
 * Revision 5.13  1992/01/24  18:44:19  eggert
 * Add support for bad_chmod_close, bad_creat0.
 *
 * Revision 5.12  1992/01/06  02:42:34  eggert
 * Add setmode parameter to chnamemod.  addsymbol now reports changes.
 * while (E) ; -> while (E) continue;
 *
 * Revision 5.11  1991/11/03  01:11:44  eggert
 * Move the warning about link breaking to where they're actually being broken.
 *
 * Revision 5.10  1991/10/07  17:32:46  eggert
 * Support piece tables even if !has_mmap.  Fix rare NFS bugs.
 *
 * Revision 5.9  1991/09/17  19:07:40  eggert
 * SGI readlink() yields ENXIO, not EINVAL, for nonlinks.
 *
 * Revision 5.8  1991/08/19  03:13:55  eggert
 * Add piece tables, NFS bug workarounds.  Catch odd filenames.  Tune.
 *
 * Revision 5.7  1991/04/21  11:58:21  eggert
 * Fix errno bugs.  Add -x, RCSINIT, MS-DOS support.
 *
 * Revision 5.6  1991/02/25  07:12:40  eggert
 * Fix setuid bug.  Support new link behavior.  Work around broken "w+" fopen.
 *
 * Revision 5.5  1990/12/30  05:07:35  eggert
 * Fix report of busy RCS files when !defined(O_CREAT) | !defined(O_EXCL).
 *
 * Revision 5.4  1990/11/01  05:03:40  eggert
 * Permit arbitrary data in comment leaders.
 *
 * Revision 5.3  1990/09/11  02:41:13  eggert
 * Tune expandline().
 *
 * Revision 5.2  1990/09/04  08:02:21  eggert
 * Count RCS lines better.  Improve incomplete line handling.
 *
 * Revision 5.1  1990/08/29  07:13:56  eggert
 * Add -kkvl.
 * Fix bug when getting revisions to files ending in incomplete lines.
 * Fix bug in comment leader expansion.
 *
 * Revision 5.0  1990/08/22  08:12:47  eggert
 * Don't require final newline.
 * Don't append "checked in with -k by " to logs,
 * so that checking in a program with -k doesn't change it.
 * Don't generate trailing white space for empty comment leader.
 * Remove compile-time limits; use malloc instead.  Add -k, -V.
 * Permit dates past 1999/12/31.  Make lock and temp files faster and safer.
 * Ansify and Posixate.  Check diff's output.
 *
 * Revision 4.8  89/05/01  15:12:35  narten
 * changed copyright header to reflect current distribution rules
 * 
 * Revision 4.7  88/11/08  13:54:14  narten
 * misplaced semicolon caused infinite loop
 * 
 * Revision 4.6  88/08/09  19:12:45  eggert
 * Shrink stdio code size; allow cc -R.
 * 
 * Revision 4.5  87/12/18  11:38:46  narten
 * Changes from the 43. version. Don't know the significance of the
 * first change involving "rewind". Also, additional "lint" cleanup.
 * (Guy Harris)
 * 
 * Revision 4.4  87/10/18  10:32:21  narten
 * Updating version numbers. Changes relative to version 1.1 actually
 * relative to 4.1
 * 
 * Revision 1.4  87/09/24  13:59:29  narten
 * Sources now pass through lint (if you ignore printf/sprintf/fprintf 
 * warnings)
 * 
 * Revision 1.3  87/09/15  16:39:39  shepler
 * added an initializatin of the variables editline and linecorr
 * this will be done each time a file is processed.
 * (there was an obscure bug where if co was used to retrieve multiple files
 *  it would dump)
 * fix attributed to  Roy Morris @FileNet Corp ...!felix!roy
 * 
 * Revision 1.2  87/03/27  14:22:17  jenkins
 * Port to suns
 * 
 * Revision 4.1  83/05/12  13:10:30  wft
 * Added new markers Id and RCSfile; added locker to Header and Id.
 * Overhauled expandline completely() (problem with $01234567890123456789@).
 * Moved trymatch() and marker table to rcskeys.c.
 * 
 * Revision 3.7  83/05/12  13:04:39  wft
 * Added retry to expandline to resume after failed match which ended in $.
 * Fixed truncation problem for $19chars followed by@@.
 * Log no longer expands full path of RCS file.
 * 
 * Revision 3.6  83/05/11  16:06:30  wft
 * added retry to expandline to resume after failed match which ended in $.
 * Fixed truncation problem for $19chars followed by@@.
 * 
 * Revision 3.5  82/12/04  13:20:56  wft
 * Added expansion of keyword Locker.
 *
 * Revision 3.4  82/12/03  12:26:54  wft
 * Added line number correction in case editing does not start at the
 * beginning of the file.
 * Changed keyword expansion to always print a space before closing KDELIM;
 * Expansion for Header shortened.
 *
 * Revision 3.3  82/11/14  14:49:30  wft
 * removed Suffix from keyword expansion. Replaced fclose with ffclose.
 * keyreplace() gets log message from delta, not from curlogmsg.
 * fixed expression overflow in while(c=putc(GETC....
 * checked nil printing.
 *
 * Revision 3.2  82/10/18  21:13:39  wft
 * I added checks for write errors during the co process, and renamed
 * expandstring() to xpandstring().
 *
 * Revision 3.1  82/10/13  15:52:55  wft
 * changed type of result of getc() from char to int.
 * made keyword expansion loop in expandline() portable to machines
 * without sign-extension.
 */


#include "rcsbase.h"

libId(editId, "$Id: rcsedit.c,v 5.19 1995/06/16 06:19:24 eggert Exp $")

static void editEndsPrematurely P((void)) exiting;
static void editLineNumberOverflow P((void)) exiting;
static void escape_string P((FILE*,char const*));
static void keyreplace P((enum markers,struct hshentry const*,int,RILE*,FILE*,int));

FILE *fcopy;		 /* result file descriptor			    */
char const *resultname;	 /* result pathname				    */
int locker_expansion;	 /* should the locker name be appended to Id val?   */
#if !large_memory
	static RILE *fedit; /* edit file descriptor */
	static char const *editname; /* edit pathname */
#endif
static long editline; /* edit line counter; #lines before cursor   */
static long linecorr; /* #adds - #deletes in each edit run.		    */
               /*used to correct editline in case file is not rewound after */
               /* applying one delta                                        */

/* indexes into dirtpname */
#define lockdirtp_index 0
#define newRCSdirtp_index bad_creat0
#define newworkdirtp_index (newRCSdirtp_index+1)
#define DIRTEMPNAMES (newworkdirtp_index + 1)

enum maker {notmade, real, effective};
static struct buf dirtpname[DIRTEMPNAMES];	/* unlink these when done */
static enum maker volatile dirtpmaker[DIRTEMPNAMES];	/* if these are set */
#define lockname (dirtpname[lockdirtp_index].string)
#define newRCSname (dirtpname[newRCSdirtp_index].string)


#if has_NFS || bad_unlink
	int
un_link(s)
	char const *s;
/*
 * Remove S, even if it is unwritable.
 * Ignore unlink() ENOENT failures; NFS generates bogus ones.
 */
{
#	if bad_unlink
		if (unlink(s) == 0)
			return 0;
		else {
			int e = errno;
			/*
			* Forge ahead even if errno == ENOENT; some completely
			* brain-damaged hosts (e.g. PCTCP 2.2) yield ENOENT
			* even for existing unwritable files.
			*/
			if (chmod(s, S_IWUSR) != 0) {
				errno = e;
				return -1;
			}
		}
#	endif
#	if has_NFS
		return unlink(s)==0 || errno==ENOENT  ?  0  :  -1;
#	else
		return unlink(s);
#	endif
}
#endif

#if !has_rename
#  if !has_NFS
#	define do_link(s,t) link(s,t)
#  else
	static int do_link P((char const*,char const*));
	static int
do_link(s, t)
	char const *s, *t;
/* Link S to T, ignoring bogus EEXIST problems due to NFS failures.  */
{
	int r = link(s, t);

	if (r != 0  &&  errno == EEXIST) {
		struct stat sb, tb;
		if (
		    stat(s, &sb) == 0  &&
		    stat(t, &tb) == 0  &&
		    same_file(sb, tb, 0)
		)
			r = 0;
		errno = EEXIST;
	}
	return r;
}
#  endif
#endif


	static void
editEndsPrematurely()
{
	fatserror("edit script ends prematurely");
}

	static void
editLineNumberOverflow()
{
	fatserror("edit script refers to line past end of file");
}


#if large_memory

#if has_memmove
#	define movelines(s1, s2, n) VOID memmove(s1, s2, (n)*sizeof(Iptr_type))
#else
	static void movelines P((Iptr_type*,Iptr_type const*,long));
	static void
movelines(s1, s2, n)
	register Iptr_type *s1;
	register Iptr_type const *s2;
	register long n;
{
	if (s1 < s2)
		do {
			*s1++ = *s2++;
		} while (--n);
	else {
		s1 += n;
		s2 += n;
		do {
			*--s1 = *--s2;
		} while (--n);
	}
}
#endif

static void deletelines P((long,long));
static void finisheditline P((RILE*,FILE*,Iptr_type,struct hshentry const*));
static void insertline P((long,Iptr_type));
static void snapshotline P((FILE*,Iptr_type));

/*
 * `line' contains pointers to the lines in the currently `edited' file.
 * It is a 0-origin array that represents linelim-gapsize lines.
 * line[0 .. gap-1] and line[gap+gapsize .. linelim-1] hold pointers to lines.
 * line[gap .. gap+gapsize-1] contains garbage.
 *
 * Any @s in lines are duplicated.
 * Lines are terminated by \n, or (for a last partial line only) by single @.
 */
static Iptr_type *line;
static size_t gap, gapsize, linelim;

	static void
insertline(n, l)
	long n;
	Iptr_type l;
/* Before line N, insert line L.  N is 0-origin.  */
{
	if (linelim-gapsize < n)
	    editLineNumberOverflow();
	if (!gapsize)
	    line =
		!linelim ?
			tnalloc(Iptr_type, linelim = gapsize = 1024)
		: (
			gap = gapsize = linelim,
			trealloc(Iptr_type, line, linelim <<= 1)
		);
	if (n < gap)
	    movelines(line+n+gapsize, line+n, gap-n);
	else if (gap < n)
	    movelines(line+gap, line+gap+gapsize, n-gap);

	line[n] = l;
	gap = n + 1;
	gapsize--;
}

	static void
deletelines(n, nlines)
	long n, nlines;
/* Delete lines N through N+NLINES-1.  N is 0-origin.  */
{
	long l = n + nlines;
	if (linelim-gapsize < l  ||  l < n)
	    editLineNumberOverflow();
	if (l < gap)
	    movelines(line+l+gapsize, line+l, gap-l);
	else if (gap < n)
	    movelines(line+gap, line+gap+gapsize, n-gap);

	gap = n;
	gapsize += nlines;
}

	static void
snapshotline(f, l)
	register FILE *f;
	register Iptr_type l;
{
	register int c;
	do {
		if ((c = *l++) == SDELIM  &&  *l++ != SDELIM)
			return;
		aputc_(c, f)
	} while (c != '\n');
}

	void
snapshotedit(f)
	FILE *f;
/* Copy the current state of the edits to F.  */
{
	register Iptr_type *p, *lim, *l=line;
	for (p=l, lim=l+gap;  p<lim;  )
		snapshotline(f, *p++);
	for (p+=gapsize, lim=l+linelim;  p<lim;  )
		snapshotline(f, *p++);
}

	static void
finisheditline(fin, fout, l, delta)
	RILE *fin;
	FILE *fout;
	Iptr_type l;
	struct hshentry const *delta;
{
	fin->ptr = l;
	if (expandline(fin, fout, delta, true, (FILE*)0, true)  <  0)
		faterror("finisheditline internal error");
}

	void
finishedit(delta, outfile, done)
	struct hshentry const *delta;
	FILE *outfile;
	int done;
/*
 * Doing expansion if DELTA is set, output the state of the edits to OUTFILE.
 * But do nothing unless DONE is set (which means we are on the last pass).
 */
{
	if (done) {
		openfcopy(outfile);
		outfile = fcopy;
		if (!delta)
			snapshotedit(outfile);
		else {
			register Iptr_type *p, *lim, *l = line;
			register RILE *fin = finptr;
			Iptr_type here = fin->ptr;
			for (p=l, lim=l+gap;  p<lim;  )
				finisheditline(fin, outfile, *p++, delta);
			for (p+=gapsize, lim=l+linelim;  p<lim;  )
				finisheditline(fin, outfile, *p++, delta);
			fin->ptr = here;
		}
	}
}

/* Open a temporary NAME for output, truncating any previous contents.  */
#   define fopen_update_truncate(name) fopenSafer(name, FOPEN_W_WORK)
#else /* !large_memory */
    static FILE * fopen_update_truncate P((char const*));
    static FILE *
fopen_update_truncate(name)
    char const *name;
{
	if (bad_fopen_wplus  &&  un_link(name) != 0)
		efaterror(name);
	return fopenSafer(name, FOPEN_WPLUS_WORK);
}
#endif


	void
openfcopy(f)
	FILE *f;
{
	if (!(fcopy = f)) {
		if (!resultname)
			resultname = maketemp(2);
		if (!(fcopy = fopen_update_truncate(resultname)))
			efaterror(resultname);
	}
}


#if !large_memory

	static void swapeditfiles P((FILE*));
	static void
swapeditfiles(outfile)
	FILE *outfile;
/* Function: swaps resultname and editname, assigns fedit=fcopy,
 * and rewinds fedit for reading.  Set fcopy to outfile if nonnull;
 * otherwise, set fcopy to be resultname opened for reading and writing.
 */
{
	char const *tmpptr;

	editline = 0;  linecorr = 0;
	Orewind(fcopy);
	fedit = fcopy;
	tmpptr=editname; editname=resultname; resultname=tmpptr;
	openfcopy(outfile);
}

	void
snapshotedit(f)
	FILE *f;
/* Copy the current state of the edits to F.  */
{
	finishedit((struct hshentry *)0, (FILE*)0, false);
	fastcopy(fedit, f);
	Irewind(fedit);
}

	void
finishedit(delta, outfile, done)
	struct hshentry const *delta;
	FILE *outfile;
	int done;
/* copy the rest of the edit file and close it (if it exists).
 * if delta, perform keyword substitution at the same time.
 * If DONE is set, we are finishing the last pass.
 */
{
	register RILE *fe;
	register FILE *fc;

	fe = fedit;
	if (fe) {
		fc = fcopy;
		if (delta) {
			while (1 < expandline(fe,fc,delta,false,(FILE*)0,true))
				;
                } else {
			fastcopy(fe,fc);
                }
		Ifclose(fe);
        }
	if (!done)
		swapeditfiles(outfile);
}
#endif



#if large_memory
#	define copylines(upto,delta) (editline = (upto))
#else
	static void copylines P((long,struct hshentry const*));
	static void
copylines(upto, delta)
	register long upto;
	struct hshentry const *delta;
/*
 * Copy input lines editline+1..upto from fedit to fcopy.
 * If delta, keyword expansion is done simultaneously.
 * editline is updated. Rewinds a file only if necessary.
 */
{
	register int c;
	declarecache;
	register FILE *fc;
	register RILE *fe;

	if (upto < editline) {
                /* swap files */
		finishedit((struct hshentry *)0, (FILE*)0, false);
                /* assumes edit only during last pass, from the beginning*/
        }
	fe = fedit;
	fc = fcopy;
	if (editline < upto)
	    if (delta)
		do {
		    if (expandline(fe,fc,delta,false,(FILE*)0,true) <= 1)
			editLineNumberOverflow();
		} while (++editline < upto);
	    else {
		setupcache(fe); cache(fe);
		do {
			do {
				cachegeteof_(c, editLineNumberOverflow();)
				aputc_(c, fc)
			} while (c != '\n');
		} while (++editline < upto);
		uncache(fe);
	    }
}
#endif



	void
xpandstring(delta)
	struct hshentry const *delta;
/* Function: Reads a string terminated by SDELIM from finptr and writes it
 * to fcopy. Double SDELIM is replaced with single SDELIM.
 * Keyword expansion is performed with data from delta.
 * If foutptr is nonnull, the string is also copied unchanged to foutptr.
 */
{
	while (1 < expandline(finptr,fcopy,delta,true,foutptr,true))
		continue;
}


	void
copystring()
/* Function: copies a string terminated with a single SDELIM from finptr to
 * fcopy, replacing all double SDELIM with a single SDELIM.
 * If foutptr is nonnull, the string also copied unchanged to foutptr.
 * editline is incremented by the number of lines copied.
 * Assumption: next character read is first string character.
 */
{	register c;
	declarecache;
	register FILE *frew, *fcop;
	register int amidline;
	register RILE *fin;

	fin = finptr;
	setupcache(fin); cache(fin);
	frew = foutptr;
	fcop = fcopy;
	amidline = false;
	for (;;) {
		GETC_(frew,c)
		switch (c) {
		    case '\n':
			++editline;
			++rcsline;
			amidline = false;
			break;
		    case SDELIM:
			GETC_(frew,c)
			if (c != SDELIM) {
				/* end of string */
				nextc = c;
				editline += amidline;
				uncache(fin);
				return;
			}
			/* fall into */
		    default:
			amidline = true;
			break;
                }
		aputc_(c,fcop)
        }
}


	void
enterstring()
/* Like copystring, except the string is put into the edit data structure.  */
{
#if !large_memory
	editname = 0;
	fedit = 0;
	editline = linecorr = 0;
	resultname = maketemp(1);
	if (!(fcopy = fopen_update_truncate(resultname)))
		efaterror(resultname);
	copystring();
#else
	register int c;
	declarecache;
	register FILE *frew;
	register long e, oe;
	register int amidline, oamidline;
	register Iptr_type optr;
	register RILE *fin;

	e = 0;
	gap = 0;
	gapsize = linelim;
	fin = finptr;
	setupcache(fin); cache(fin);
	advise_access(fin, MADV_NORMAL);
	frew = foutptr;
	amidline = false;
	for (;;) {
		optr = cacheptr();
		GETC_(frew,c)
		oamidline = amidline;
		oe = e;
		switch (c) {
		    case '\n':
			++e;
			++rcsline;
			amidline = false;
			break;
		    case SDELIM:
			GETC_(frew,c)
			if (c != SDELIM) {
				/* end of string */
				nextc = c;
				editline = e + amidline;
				linecorr = 0;
				uncache(fin);
				return;
			}
			/* fall into */
		    default:
			amidline = true;
			break;
		}
		if (!oamidline)
			insertline(oe, optr);
	}
#endif
}




	void
#if large_memory
edit_string()
#else
  editstring(delta)
	struct hshentry const *delta;
#endif
/*
 * Read an edit script from finptr and applies it to the edit file.
#if !large_memory
 * The result is written to fcopy.
 * If delta, keyword expansion is performed simultaneously.
 * If running out of lines in fedit, fedit and fcopy are swapped.
 * editname is the name of the file that goes with fedit.
#endif
 * If foutptr is set, the edit script is also copied verbatim to foutptr.
 * Assumes that all these files are open.
 * resultname is the name of the file that goes with fcopy.
 * Assumes the next input character from finptr is the first character of
 * the edit script. Resets nextc on exit.
 */
{
        int ed; /* editor command */
        register int c;
	declarecache;
	register FILE *frew;
#	if !large_memory
		register FILE *f;
		long line_lim = LONG_MAX;
		register RILE *fe;
#	endif
	register long i;
	register RILE *fin;
#	if large_memory
		register long j;
#	endif
	struct diffcmd dc;

        editline += linecorr; linecorr=0; /*correct line number*/
	frew = foutptr;
	fin = finptr;
	setupcache(fin);
	initdiffcmd(&dc);
	while (0  <=  (ed = getdiffcmd(fin,true,frew,&dc)))
#if !large_memory
		if (line_lim <= dc.line1)
			editLineNumberOverflow();
		else
#endif
		if (!ed) {
			copylines(dc.line1-1, delta);
                        /* skip over unwanted lines */
			i = dc.nlines;
			linecorr -= i;
			editline += i;
#			if large_memory
			    deletelines(editline+linecorr, i);
#			else
			    fe = fedit;
			    do {
                                /*skip next line*/
				do {
				    Igeteof_(fe, c, { if (i!=1) editLineNumberOverflow(); line_lim = dc.dafter; break; } )
				} while (c != '\n');
			    } while (--i);
#			endif
		} else {
			/* Copy lines without deleting any.  */
			copylines(dc.line1, delta);
			i = dc.nlines;
#			if large_memory
				j = editline+linecorr;
#			endif
			linecorr += i;
#if !large_memory
			f = fcopy;
			if (delta)
			    do {
				switch (expandline(fin,f,delta,true,frew,true)){
				    case 0: case 1:
					if (i==1)
					    return;
					/* fall into */
				    case -1:
					editEndsPrematurely();
				}
			    } while (--i);
			else
#endif
			{
			    cache(fin);
			    do {
#				if large_memory
				    insertline(j++, cacheptr());
#				endif
				for (;;) {
				    GETC_(frew, c)
				    if (c==SDELIM) {
					GETC_(frew, c)
					if (c!=SDELIM) {
					    if (--i)
						editEndsPrematurely();
					    nextc = c;
					    uncache(fin);
					    return;
					}
				    }
#				    if !large_memory
					aputc_(c, f)
#				    endif
				    if (c == '\n')
					break;
				}
				++rcsline;
			    } while (--i);
			    uncache(fin);
			}
                }
}



/* The rest is for keyword expansion */



	int
expandline(infile, outfile, delta, delimstuffed, frewfile, dolog)
	RILE *infile;
	FILE *outfile, *frewfile;
	struct hshentry const *delta;
	int delimstuffed, dolog;
/*
 * Read a line from INFILE and write it to OUTFILE.
 * Do keyword expansion with data from DELTA.
 * If DELIMSTUFFED is true, double SDELIM is replaced with single SDELIM.
 * If FREWFILE is set, copy the line unchanged to FREWFILE.
 * DELIMSTUFFED must be true if FREWFILE is set.
 * Append revision history to log only if DOLOG is set.
 * Yields -1 if no data is copied, 0 if an incomplete line is copied,
 * 2 if a complete line is copied; adds 1 to yield if expansion occurred.
 */
{
	register c;
	declarecache;
	register FILE *out, *frew;
	register char * tp;
	register int e, ds, r;
	char const *tlim;
	static struct buf keyval;
        enum markers matchresult;

	setupcache(infile); cache(infile);
	out = outfile;
	frew = frewfile;
	ds = delimstuffed;
	bufalloc(&keyval, keylength+3);
	e = 0;
	r = -1;

        for (;;) {
	    if (ds)
		GETC_(frew, c)
	    else
		cachegeteof_(c, goto uncache_exit;)
	    for (;;) {
		switch (c) {
		    case SDELIM:
			if (ds) {
			    GETC_(frew, c)
			    if (c != SDELIM) {
                                /* end of string */
                                nextc=c;
				goto uncache_exit;
			    }
			}
			/* fall into */
		    default:
			aputc_(c,out)
			r = 0;
			break;

		    case '\n':
			rcsline += ds;
			aputc_(c,out)
			r = 2;
			goto uncache_exit;

		    case KDELIM:
			r = 0;
                        /* check for keyword */
                        /* first, copy a long enough string into keystring */
			tp = keyval.string;
			*tp++ = KDELIM;
			for (;;) {
			    if (ds)
				GETC_(frew, c)
			    else
				cachegeteof_(c, goto keystring_eof;)
			    if (tp <= &keyval.string[keylength])
				switch (ctab[c]) {
				    case LETTER: case Letter:
					*tp++ = c;
					continue;
				    default:
					break;
				}
			    break;
                        }
			*tp++ = c; *tp = '\0';
			matchresult = trymatch(keyval.string+1);
			if (matchresult==Nomatch) {
				tp[-1] = 0;
				aputs(keyval.string, out);
				continue;   /* last c handled properly */
			}

			/* Now we have a keyword terminated with a K/VDELIM */
			if (c==VDELIM) {
			      /* try to find closing KDELIM, and replace value */
			      tlim = keyval.string + keyval.size;
			      for (;;) {
				      if (ds)
					GETC_(frew, c)
				      else
					cachegeteof_(c, goto keystring_eof;)
				      if (c=='\n' || c==KDELIM)
					break;
				      *tp++ =c;
				      if (tlim <= tp)
					  tp = bufenlarge(&keyval, &tlim);
				      if (c==SDELIM && ds) { /*skip next SDELIM */
						GETC_(frew, c)
						if (c != SDELIM) {
							/* end of string before closing KDELIM or newline */
							nextc = c;
							goto keystring_eof;
						}
				      }
			      }
			      if (c!=KDELIM) {
				    /* couldn't find closing KDELIM -- give up */
				    *tp = 0;
				    aputs(keyval.string, out);
				    continue;   /* last c handled properly */
			      }
			}
			/* now put out the new keyword value */
			uncache(infile);
			keyreplace(matchresult, delta, ds, infile, out, dolog);
			cache(infile);
			e = 1;
			break;
                }
		break;
	    }
        }

    keystring_eof:
	*tp = 0;
	aputs(keyval.string, out);
    uncache_exit:
	uncache(infile);
	return r + e;
}


	static void
escape_string(out, s)
	register FILE *out;
	register char const *s;
/* Output to OUT the string S, escaping chars that would break `ci -k'.  */
{
    register char c;
    for (;;)
	switch ((c = *s++)) {
	    case 0: return;
	    case '\t': aputs("\\t", out); break;
	    case '\n': aputs("\\n", out); break;
	    case '\r': aputs("\\r", out); break;
	    case ' ': aputs("\\040", out); break;
	    case KDELIM: aputs("\\044", out); break;
	    case '\\': if (VERSION(5)<=RCSversion) {aputs("\\\\", out); break;}
	    /* fall into */
	    default: aputc_(c, out) break;
	}
}

char const ciklog[ciklogsize] = "checked in with -k by ";

	static void
keyreplace(marker, delta, delimstuffed, infile, out, dolog)
	enum markers marker;
	register struct hshentry const *delta;
	int delimstuffed;
	RILE *infile;
	register FILE *out;
	int dolog;
/* function: outputs the keyword value(s) corresponding to marker.
 * Attributes are derived from delta.
 */
{
	register char const *sp, *cp, *date;
	register int c;
	register size_t cs, cw, ls;
	char const *sp1;
	char datebuf[datesize + zonelenmax];
	int RCSv;
	int exp;

	sp = Keyword[(int)marker];
	exp = Expand;
	date = delta->date;
	RCSv = RCSversion;

	if (exp != VAL_EXPAND)
	    aprintf(out, "%c%s", KDELIM, sp);
	if (exp != KEY_EXPAND) {

	    if (exp != VAL_EXPAND)
		aprintf(out, "%c%c", VDELIM,
			marker==Log && RCSv<VERSION(5)  ?  '\t'  :  ' '
		);

	    switch (marker) {
	    case Author:
		aputs(delta->author, out);
                break;
	    case Date:
		aputs(date2str(date,datebuf), out);
                break;
	    case Id:
	    case Header:
		escape_string(out,
			marker==Id || RCSv<VERSION(4)
			? basefilename(RCSname)
			: getfullRCSname()
		);
		aprintf(out, " %s %s %s %s",
			delta->num,
			date2str(date, datebuf),
			delta->author,
			  RCSv==VERSION(3) && delta->lockedby ? "Locked"
			: delta->state
		);
		if (delta->lockedby)
		    if (VERSION(5) <= RCSv) {
			if (locker_expansion || exp==KEYVALLOCK_EXPAND)
			    aprintf(out, " %s", delta->lockedby);
		    } else if (RCSv == VERSION(4))
			aprintf(out, " Locker: %s", delta->lockedby);
                break;
	    case Locker:
		if (delta->lockedby)
		    if (
				locker_expansion
			||	exp == KEYVALLOCK_EXPAND
			||	RCSv <= VERSION(4)
		    )
			aputs(delta->lockedby, out);
                break;
	    case Log:
	    case RCSfile:
		escape_string(out, basefilename(RCSname));
                break;
	    case Name:
		if (delta->name)
			aputs(delta->name, out);
		break;
	    case Revision:
		aputs(delta->num, out);
                break;
	    case Source:
		escape_string(out, getfullRCSname());
                break;
	    case State:
		aputs(delta->state, out);
                break;
	    default:
		break;
	    }
	    if (exp != VAL_EXPAND)
		afputc(' ', out);
	}
	if (exp != VAL_EXPAND)
	    afputc(KDELIM, out);

	if (marker == Log   &&  dolog) {
		struct buf leader;

		sp = delta->log.string;
		ls = delta->log.size;
		if (sizeof(ciklog)-1<=ls && !memcmp(sp,ciklog,sizeof(ciklog)-1))
			return;
		bufautobegin(&leader);
		if (RCSversion < VERSION(5)) {
		    cp = Comment.string;
		    cs = Comment.size;
		} else {
		    int kdelim_found = 0;
		    Ioffset_type chars_read = Itell(infile);
		    declarecache;
		    setupcache(infile); cache(infile);

		    c = 0; /* Pacify `gcc -Wall'.  */

		    /*
		    * Back up to the start of the current input line,
		    * setting CS to the number of characters before `$Log'.
		    */
		    cs = 0;
		    for (;;) {
			if (!--chars_read)
			    goto done_backing_up;
			cacheunget_(infile, c)
			if (c == '\n')
			    break;
			if (c == SDELIM  &&  delimstuffed) {
			    if (!--chars_read)
				break;
			    cacheunget_(infile, c)
			    if (c != SDELIM) {
				cacheget_(c)
				break;
			    }
			}
			cs += kdelim_found;
			kdelim_found |= c==KDELIM;
		    }
		    cacheget_(c)
		  done_backing_up:;

		    /* Copy characters before `$Log' into LEADER.  */
		    bufalloc(&leader, cs);
		    cp = leader.string;
		    for (cw = 0;  cw < cs;  cw++) {
			leader.string[cw] = c;
			if (c == SDELIM  &&  delimstuffed)
			    cacheget_(c)
			cacheget_(c)
		    }

		    /* Convert traditional C or Pascal leader to ` *'.  */
		    for (cw = 0;  cw < cs;  cw++)
			if (ctab[(unsigned char) cp[cw]] != SPACE)
			    break;
		    if (
			cw+1 < cs
			&&  cp[cw+1] == '*'
			&&  (cp[cw] == '/'  ||  cp[cw] == '(')
		    ) {
			size_t i = cw+1;
			for (;;)
			    if (++i == cs) {
				warn(
				    "`%c* $Log' is obsolescent; use ` * $Log'.",
				    cp[cw]
				);
				leader.string[cw] = ' ';
				break;
			    } else if (ctab[(unsigned char) cp[i]] != SPACE)
				break;
		    }

		    /* Skip `$Log ... $' string.  */
		    do {
			cacheget_(c)
		    } while (c != KDELIM);
		    uncache(infile);
		}
		afputc('\n', out);
		awrite(cp, cs, out);
		sp1 = date2str(date, datebuf);
		if (VERSION(5) <= RCSv) {
		    aprintf(out, "Revision %s  %s  %s",
			delta->num, sp1, delta->author
		    );
		} else {
		    /* oddity: 2 spaces between date and time, not 1 as usual */
		    sp1 = strchr(sp1, ' ');
		    aprintf(out, "Revision %s  %.*s %s  %s",
			delta->num, (int)(sp1-datebuf), datebuf, sp1,
			delta->author
		    );
		}
		/* Do not include state: it may change and is not updated.  */
		cw = cs;
		if (VERSION(5) <= RCSv)
		    for (;  cw && (cp[cw-1]==' ' || cp[cw-1]=='\t');  --cw)
			continue;
		for (;;) {
		    afputc('\n', out);
		    awrite(cp, cw, out);
		    if (!ls)
			break;
		    --ls;
		    c = *sp++;
		    if (c != '\n') {
			awrite(cp+cw, cs-cw, out);
			do {
			    afputc(c,out);
			    if (!ls)
				break;
			    --ls;
			    c = *sp++;
			} while (c != '\n');
		    }
		}
		bufautoend(&leader);
	}
}

#if has_readlink
	static int resolve_symlink P((struct buf*));
	static int
resolve_symlink(L)
	struct buf *L;
/*
 * If L is a symbolic link, resolve it to the name that it points to.
 * If unsuccessful, set errno and yield -1.
 * If it points to an existing file, yield 1.
 * Otherwise, set errno=ENOENT and yield 0.
 */
{
	char *b, a[SIZEABLE_PATH];
	int e;
	size_t s;
	ssize_t r;
	struct buf bigbuf;
	int linkcount = MAXSYMLINKS;

	b = a;
	s = sizeof(a);
	bufautobegin(&bigbuf);
	while ((r = readlink(L->string,b,s))  !=  -1)
	    if (r == s) {
		bufalloc(&bigbuf, s<<1);
		b = bigbuf.string;
		s = bigbuf.size;
	    } else if (!linkcount--) {
#		ifndef ELOOP
		    /*
		    * Some pedantic Posix 1003.1-1990 hosts have readlink
		    * but not ELOOP.  Approximate ELOOP with EMLINK.
		    */
#		    define ELOOP EMLINK
#		endif
		errno = ELOOP;
		return -1;
	    } else {
		/* Splice symbolic link into L.  */
		b[r] = '\0';
		L->string[
		  ROOTPATH(b)  ?  0  :  basefilename(L->string) - L->string
		] = '\0';
		bufscat(L, b);
	    }
	e = errno;
	bufautoend(&bigbuf);
	errno = e;
	switch (e) {
	    case readlink_isreg_errno: return 1;
	    case ENOENT: return 0;
	    default: return -1;
	}
}
#endif

	RILE *
rcswriteopen(RCSbuf, status, mustread)
	struct buf *RCSbuf;
	struct stat *status;
	int mustread;
/*
 * Create the lock file corresponding to RCSBUF.
 * Then try to open RCSBUF for reading and yield its RILE* descriptor.
 * Put its status into *STATUS too.
 * MUSTREAD is true if the file must already exist, too.
 * If all goes well, discard any previously acquired locks,
 * and set fdlock to the file descriptor of the RCS lockfile.
 */
{
	register char *tp;
	register char const *sp, *RCSpath, *x;
	RILE *f;
	size_t l;
	int e, exists, fdesc, fdescSafer, r, waslocked;
	struct buf *dirt;
	struct stat statbuf;

	waslocked  =  0 <= fdlock;
	exists =
#		if has_readlink
			resolve_symlink(RCSbuf);
#		else
			    stat(RCSbuf->string, &statbuf) == 0  ?  1
			:   errno==ENOENT ? 0 : -1;
#		endif
	if (exists < (mustread|waslocked))
		/*
		 * There's an unusual problem with the RCS file;
		 * or the RCS file doesn't exist,
		 * and we must read or we already have a lock elsewhere.
		 */
		return 0;

	RCSpath = RCSbuf->string;
	sp = basefilename(RCSpath);
	l = sp - RCSpath;
	dirt = &dirtpname[waslocked];
	bufscpy(dirt, RCSpath);
	tp = dirt->string + l;
	x = rcssuffix(RCSpath);
#	if has_readlink | pseudo_symlinks
	    if (!x) {
		error("symbolic link to non RCS file `%s'", RCSpath);
		errno = EINVAL;
		return 0;
	    }
#	endif
	if (*sp == *x) {
		error("RCS pathname `%s' incompatible with suffix `%s'", sp, x);
		errno = EINVAL;
		return 0;
	}
	/* Create a lock filename that is a function of the RCS filename.  */
	if (*x) {
		/*
		 * The suffix is nonempty.
		 * The lock filename is the first char of of the suffix,
		 * followed by the RCS filename with last char removed.  E.g.:
		 *	foo,v	RCS filename with suffix ,v
		 *	,foo,	lock filename
		 */
		*tp++ = *x;
		while (*sp)
			*tp++ = *sp++;
		*--tp = 0;
	} else {
		/*
		 * The suffix is empty.
		 * The lock filename is the RCS filename
		 * with last char replaced by '_'.
		 */
		while ((*tp++ = *sp++))
			continue;
		tp -= 2;
		if (*tp == '_') {
			error("RCS pathname `%s' ends with `%c'", RCSpath, *tp);
			errno = EINVAL;
			return 0;
		}
		*tp = '_';
	}

	sp = dirt->string;

	f = 0;

	/*
	* good news:
	*	open(f, O_CREAT|O_EXCL|O_TRUNC|..., OPEN_CREAT_READONLY)
	*	is atomic according to Posix 1003.1-1990.
	* bad news:
	*	NFS ignores O_EXCL and doesn't comply with Posix 1003.1-1990.
	* good news:
	*	(O_TRUNC,OPEN_CREAT_READONLY) normally guarantees atomicity
	*	even with NFS.
	* bad news:
	*	If you're root, (O_TRUNC,OPEN_CREAT_READONLY) doesn't
	*	guarantee atomicity.
	* good news:
	*	Root-over-the-wire NFS access is rare for security reasons.
	*	This bug has never been reported in practice with RCS.
	* So we don't worry about this bug.
	*
	* An even rarer NFS bug can occur when clients retry requests.
	* This can happen in the usual case of NFS over UDP.
	* Suppose client A releases a lock by renaming ",f," to "f,v" at
	* about the same time that client B obtains a lock by creating ",f,",
	* and suppose A's first rename request is delayed, so A reissues it.
	* The sequence of events might be:
	*	A sends rename(",f,", "f,v")
	*	B sends create(",f,")
	*	A sends retry of rename(",f,", "f,v")
	*	server receives, does, and acknowledges A's first rename()
	*	A receives acknowledgment, and its RCS program exits
	*	server receives, does, and acknowledges B's create()
	*	server receives, does, and acknowledges A's retry of rename()
	* This not only wrongly deletes B's lock, it removes the RCS file!
	* Most NFS implementations have idempotency caches that usually prevent
	* this scenario, but such caches are finite and can be overrun.
	* This problem afflicts not only RCS, which uses open() and rename()
	* to get and release locks; it also afflicts the traditional
	* Unix method of using link() and unlink() to get and release locks,
	* and the less traditional method of using mkdir() and rmdir().
	* There is no easy workaround.
	* Any new method based on lockf() seemingly would be incompatible with
	* the old methods; besides, lockf() is notoriously buggy under NFS.
	* Since this problem afflicts scads of Unix programs, but is so rare
	* that nobody seems to be worried about it, we won't worry either.
	*/
#	if !open_can_creat
#		define create(f) creat(f, OPEN_CREAT_READONLY)
#	else
#		define create(f) open(f, OPEN_O_BINARY|OPEN_O_LOCK|OPEN_O_WRONLY|O_CREAT|O_EXCL/*|O_TRUNC*/, OPEN_CREAT_READONLY)
#	endif

	catchints();
	ignoreints();

	/*
	 * Create a lock file for an RCS file.  This should be atomic, i.e.
	 * if two processes try it simultaneously, at most one should succeed.
	 */
	seteid();
	fdesc = create(sp);
	fdescSafer = fdSafer(fdesc); /* Do it now; setrid might use stderr.  */
	e = errno;
	setrid();

	if (0 <= fdesc)
		dirtpmaker[0] = effective;

	if (fdescSafer < 0) {
		if (e == EACCES  &&  stat(sp,&statbuf) == 0)
			/* The RCS file is busy.  */
			e = EEXIST;
	} else {
		e = ENOENT;
		if (exists) {
		    f = Iopen(RCSpath, FOPEN_RB, status);
		    e = errno;
		    if (f && waslocked) {
			/* Discard the previous lock in favor of this one.  */
			ORCSclose();
			seteid();
			r = un_link(lockname);
			e = errno;
			setrid();
			if (r != 0)
			    enfaterror(e, lockname);
			bufscpy(&dirtpname[lockdirtp_index], sp);
		    }
		}
		fdlock = fdescSafer;
	}

	restoreints();

	errno = e;
	return f;
}

	void
keepdirtemp(name)
	char const *name;
/* Do not unlink name, either because it's not there any more,
 * or because it has already been unlinked.
 */
{
	register int i;
	for (i=DIRTEMPNAMES; 0<=--i; )
		if (dirtpname[i].string == name) {
			dirtpmaker[i] = notmade;
			return;
		}
	faterror("keepdirtemp");
}

	char const *
makedirtemp(isworkfile)
	int isworkfile;
/*
 * Create a unique pathname and store it into dirtpname.
 * Because of storage in tpnames, dirtempunlink() can unlink the file later.
 * Return a pointer to the pathname created.
 * If ISWORKFILE is 1, put it into the working file's directory;
 * if 0, put the unique file in RCSfile's directory.
 */
{
	register char *tp, *np;
	register size_t dl;
	register struct buf *bn;
	register char const *name = isworkfile ? workname : RCSname;

	dl = basefilename(name) - name;
	bn = &dirtpname[newRCSdirtp_index + isworkfile];
	bufalloc(bn,
#		if has_mktemp
			dl + 9
#		else
			strlen(name) + 3
#		endif
	);
	bufscpy(bn, name);
	np = tp = bn->string;
	tp += dl;
	*tp++ = '_';
	*tp++ = '0'+isworkfile;
	catchints();
#	if has_mktemp
		VOID strcpy(tp, "XXXXXX");
		if (!mktemp(np) || !*np)
		    faterror("can't make temporary pathname `%.*s_%cXXXXXX'",
			(int)dl, name, '0'+isworkfile
		    );
#	else
		/*
		 * Posix 1003.1-1990 has no reliable way
		 * to create a unique file in a named directory.
		 * We fudge here.  If the filename is abcde,
		 * the temp filename is _Ncde where N is a digit.
		 */
		name += dl;
		if (*name) name++;
		if (*name) name++;
		VOID strcpy(tp, name);
#	endif
	dirtpmaker[newRCSdirtp_index + isworkfile] = real;
	return np;
}

	void
dirtempunlink()
/* Clean up makedirtemp() files.  May be invoked by signal handler. */
{
	register int i;
	enum maker m;

	for (i = DIRTEMPNAMES;  0 <= --i;  )
	    if ((m = dirtpmaker[i]) != notmade) {
		if (m == effective)
		    seteid();
		VOID un_link(dirtpname[i].string);
		if (m == effective)
		    setrid();
		dirtpmaker[i] = notmade;
	    }
}


	int
#if has_prototypes
chnamemod(
	FILE **fromp, char const *from, char const *to,
	int set_mode, mode_t mode, time_t mtime
)
  /* The `#if has_prototypes' is needed because mode_t might promote to int.  */
#else
  chnamemod(fromp, from, to, set_mode, mode, mtime)
	FILE **fromp; char const *from,*to;
	int set_mode; mode_t mode; time_t mtime;
#endif
/*
 * Rename a file (with stream pointer *FROMP) from FROM to TO.
 * FROM already exists.
 * If 0 < SET_MODE, change the mode to MODE, before renaming if possible.
 * If MTIME is not -1, change its mtime to MTIME before renaming.
 * Close and clear *FROMP before renaming it.
 * Unlink TO if it already exists.
 * Return -1 on error (setting errno), 0 otherwise.
 */
{
	mode_t mode_while_renaming = mode;
	int fchmod_set_mode = 0;

#	if bad_a_rename || bad_NFS_rename
	    struct stat st;
	    if (bad_NFS_rename  ||  (bad_a_rename && set_mode <= 0)) {
		if (fstat(fileno(*fromp), &st) != 0)
		    return -1;
		if (bad_a_rename && set_mode <= 0)
		    mode = st.st_mode;
	    }
#	endif

#	if bad_a_rename
		/*
		* There's a short window of inconsistency
		* during which the lock file is writable.
		*/
		mode_while_renaming = mode|S_IWUSR;
		if (mode != mode_while_renaming)
		    set_mode = 1;
#	endif

#	if has_fchmod
	    if (0<set_mode  &&  fchmod(fileno(*fromp),mode_while_renaming) == 0)
		fchmod_set_mode = set_mode;
#	endif
	/* If bad_chmod_close, we must close before chmod.  */
	Ozclose(fromp);
	if (fchmod_set_mode<set_mode  &&  chmod(from, mode_while_renaming) != 0)
	    return -1;

	if (setmtime(from, mtime) != 0)
		return -1;

#	if !has_rename || bad_b_rename
		/*
		* There's a short window of inconsistency
		* during which TO does not exist.
		*/
		if (un_link(to) != 0  &&  errno != ENOENT)
			return -1;
#	endif

#	if has_rename
	    if (rename(from,to) != 0  &&  !(has_NFS && errno==ENOENT))
		return -1;
#	else
	    if (do_link(from,to) != 0  ||  un_link(from) != 0)
		return -1;
#	endif

#	if bad_NFS_rename
	{
	    /*
	    * Check whether the rename falsely reported success.
	    * A race condition can occur between the rename and the stat.
	    */
	    struct stat tostat;
	    if (stat(to, &tostat) != 0)
		return -1;
	    if (! same_file(st, tostat, 0)) {
		errno = EIO;
		return -1;
	    }
	}
#	endif

#	if bad_a_rename
	    if (0 < set_mode  &&  chmod(to, mode) != 0)
		return -1;
#	endif

	return 0;
}

	int
setmtime(file, mtime)
	char const *file;
	time_t mtime;
/* Set FILE's last modified time to MTIME, but do nothing if MTIME is -1.  */
{
	static struct utimbuf amtime; /* static so unused fields are zero */
	if (mtime == -1)
		return 0;
	amtime.actime = now();
	amtime.modtime = mtime;
	return utime(file, &amtime);
}



	int
findlock(delete, target)
	int delete;
	struct hshentry **target;
/*
 * Find the first lock held by caller and return a pointer
 * to the locked delta; also removes the lock if DELETE.
 * If one lock, put it into *TARGET.
 * Return 0 for no locks, 1 for one, 2 for two or more.
 */
{
	register struct rcslock *next, **trail, **found;

	found = 0;
	for (trail = &Locks;  (next = *trail);  trail = &next->nextlock)
		if (strcmp(getcaller(), next->login)  ==  0) {
			if (found) {
				rcserror("multiple revisions locked by %s; please specify one", getcaller());
				return 2;
			}
			found = trail;
		}
	if (!found)
		return 0;
	next = *found;
	*target = next->delta;
	if (delete) {
		next->delta->lockedby = 0;
		*found = next->nextlock;
	}
	return 1;
}

	int
addlock(delta, verbose)
	struct hshentry * delta;
	int verbose;
/*
 * Add a lock held by caller to DELTA and yield 1 if successful.
 * Print an error message if verbose and yield -1 if no lock is added because
 * DELTA is locked by somebody other than caller.
 * Return 0 if the caller already holds the lock.
 */
{
	register struct rcslock *next;

	for (next = Locks;  next;  next = next->nextlock)
		if (cmpnum(delta->num, next->delta->num) == 0)
			if (strcmp(getcaller(), next->login) == 0)
				return 0;
			else {
				if (verbose)
				  rcserror("Revision %s is already locked by %s.",
					delta->num, next->login
				  );
				return -1;
			}
	next = ftalloc(struct rcslock);
	delta->lockedby = next->login = getcaller();
	next->delta = delta;
	next->nextlock = Locks;
	Locks = next;
	return 1;
}


	int
addsymbol(num, name, rebind)
	char const *num, *name;
	int rebind;
/*
 * Associate with revision NUM the new symbolic NAME.
 * If NAME already exists and REBIND is set, associate NAME with NUM;
 * otherwise, print an error message and return false;
 * Return -1 if unsuccessful, 0 if no change, 1 if change.
 */
{
	register struct assoc *next;

	for (next = Symbols;  next;  next = next->nextassoc)
		if (strcmp(name, next->symbol)  ==  0)
			if (strcmp(next->num,num) == 0)
				return 0;
			else if (rebind) {
				next->num = num;
				return 1;
			} else {
				rcserror("symbolic name %s already bound to %s",
					name, next->num
				);
				return -1;
			}
	next = ftalloc(struct assoc);
	next->symbol = name;
	next->num = num;
	next->nextassoc = Symbols;
	Symbols = next;
	return 1;
}



	char const *
getcaller()
/* Get the caller's login name.  */
{
#	if has_setuid
		return getusername(euid()!=ruid());
#	else
		return getusername(false);
#	endif
}


	int
checkaccesslist()
/*
 * Return true if caller is the superuser, the owner of the
 * file, the access list is empty, or caller is on the access list.
 * Otherwise, print an error message and return false.
 */
{
	register struct access const *next;

	if (!AccessList || myself(RCSstat.st_uid) || strcmp(getcaller(),"root")==0)
		return true;

	next = AccessList;
	do {
		if (strcmp(getcaller(), next->login)  ==  0)
			return true;
	} while ((next = next->nextaccess));

	rcserror("user %s not on the access list", getcaller());
	return false;
}


	int
dorewrite(lockflag, changed)
	int lockflag, changed;
/*
 * Do nothing if LOCKFLAG is zero.
 * Prepare to rewrite an RCS file if CHANGED is positive.
 * Stop rewriting if CHANGED is zero, because there won't be any changes.
 * Fail if CHANGED is negative.
 * Return 0 on success, -1 on failure.
 */
{
	int r = 0, e;

	if (lockflag)
		if (changed) {
			if (changed < 0)
				return -1;
			putadmin();
			puttree(Head, frewrite);
			aprintf(frewrite, "\n\n%s%c", Kdesc, nextc);
			foutptr = frewrite;
		} else {
#			if bad_creat0
				int nr = !!frewrite, ne = 0;
#			endif
			ORCSclose();
			seteid();
			ignoreints();
#			if bad_creat0
				if (nr) {
					nr = un_link(newRCSname);
					ne = errno;
					keepdirtemp(newRCSname);
				}
#			endif
			r = un_link(lockname);
			e = errno;
			keepdirtemp(lockname);
			restoreints();
			setrid();
			if (r != 0)
				enerror(e, lockname);
#			if bad_creat0
				if (nr != 0) {
					enerror(ne, newRCSname);
					r = -1;
				}
#			endif
		}
	return r;
}

	int
donerewrite(changed, newRCStime)
	int changed;
	time_t newRCStime;
/*
 * Finish rewriting an RCS file if CHANGED is nonzero.
 * Set its mode if CHANGED is positive.
 * Set its modification time to NEWRCSTIME unless it is -1.
 * Return 0 on success, -1 on failure.
 */
{
	int r = 0, e = 0;
#	if bad_creat0
		int lr, le;
#	endif

	if (changed && !nerror) {
		if (finptr) {
			fastcopy(finptr, frewrite);
			Izclose(&finptr);
		}
		if (1 < RCSstat.st_nlink)
			rcswarn("breaking hard link");
		aflush(frewrite);
		seteid();
		ignoreints();
		r = chnamemod(
			&frewrite, newRCSname, RCSname, changed,
			RCSstat.st_mode & (mode_t)~(S_IWUSR|S_IWGRP|S_IWOTH),
			newRCStime
		);
		e = errno;
		keepdirtemp(newRCSname);
#		if bad_creat0
			lr = un_link(lockname);
			le = errno;
			keepdirtemp(lockname);
#		endif
		restoreints();
		setrid();
		if (r != 0) {
			enerror(e, RCSname);
			error("saved in %s", newRCSname);
		}
#		if bad_creat0
			if (lr != 0) {
				enerror(le, lockname);
				r = -1;
			}
#		endif
	}
	return r;
}

	void
ORCSclose()
{
	if (0 <= fdlock) {
		if (close(fdlock) != 0)
			efaterror(lockname);
		fdlock = -1;
	}
	Ozclose(&frewrite);
}

	void
ORCSerror()
/*
* Like ORCSclose, except we are cleaning up after an interrupt or fatal error.
* Do not report errors, since this may loop.  This is needed only because
* some brain-damaged hosts (e.g. OS/2) cannot unlink files that are open, and
* some nearly-Posix hosts (e.g. NFS) work better if the files are closed first.
* This isn't a completely reliable away to work around brain-damaged hosts,
* because of the gap between actual file opening and setting frewrite etc.,
* but it's better than nothing.
*/
{
	if (0 <= fdlock)
		VOID close(fdlock);
	if (frewrite)
		/* Avoid fclose, since stdio may not be reentrant.  */
		VOID close(fileno(frewrite));
}
