cleanup: complete the transition from stak(3) to stk(3)/sfio(3)

Having two different interfaces to the same AST stack routines is a
botch that damages code legibility. The "new" stk(3) interface is a
reimplementation (on top of sfio(3)) of the old stak(3) routines,
the latter now being just a set of macros that use the former. The
code liberally mixes both interfcaces.

I'm scare-quoted "new" above because, as the ksh93-history repo
shows, the new stk(3) interface has been present since 1995 or
before! I am not aware of any surviving copy of the original
stak(3) routines. Yet, the transition was never close to completed,
not even in the last AT&T beta from 2016.

This commit finally finishes the job. Unless I've done something
wrong, there should be no change in ksh's behaviour.

src/lib/libast/include/stak.h,
src/lib/libast/man/stak.3:
- Removed.

Every other file:
- Translate the ancient interface to the slightly less ancient one.
- Related housekeeping.

src/cmd/builtin/Mamfile

@@ -106,11 +106,9 @@ make install
 						prev ${PACKAGE_ast_INCLUDE}/shcmd.h implicit
 					done ${PACKAGE_ast_INCLUDE}/cmdext.h
 					prev ${PACKAGE_ast_INCLUDE}/shcmd.h
-					make ${PACKAGE_ast_INCLUDE}/stak.h implicit
-						make ${PACKAGE_ast_INCLUDE}/stk.h implicit
-							prev ${PACKAGE_ast_INCLUDE}/sfio.h
-						done ${PACKAGE_ast_INCLUDE}/stk.h
-					done ${PACKAGE_ast_INCLUDE}/stak.h
+					make ${PACKAGE_ast_INCLUDE}/stk.h implicit
+						prev ${PACKAGE_ast_INCLUDE}/sfio.h
+					done ${PACKAGE_ast_INCLUDE}/stk.h
 					prev ${PACKAGE_ast_INCLUDE}/error.h
 					prev ${PACKAGE_ast_INCLUDE}/ast.h
 				done ${PACKAGE_ast_INCLUDE}/cmd.h

src/cmd/ksh93/Mamfile

@@ -190,9 +190,7 @@ make install
 							prev ${PACKAGE_ast_INCLUDE}/shcmd.h implicit
 						done ${PACKAGE_ast_INCLUDE}/cmdext.h
 						prev ${PACKAGE_ast_INCLUDE}/shcmd.h
-						make ${PACKAGE_ast_INCLUDE}/stak.h implicit
-							prev ${PACKAGE_ast_INCLUDE}/stk.h
-						done ${PACKAGE_ast_INCLUDE}/stak.h
+						prev ${PACKAGE_ast_INCLUDE}/stk.h
 						prev ${PACKAGE_ast_INCLUDE}/error.h
 						prev ${PACKAGE_ast_INCLUDE}/ast.h
 					done ${PACKAGE_ast_INCLUDE}/cmd.h
@@ -229,9 +227,7 @@ make install
 							prev include/shell.h
 							prev ${PACKAGE_ast_INCLUDE}/endian.h
 							prev include/name.h
-							make include/argnod.h implicit
-								prev ${PACKAGE_ast_INCLUDE}/stak.h
-							done include/argnod.h dontcare
+							prev include/argnod.h implicit
 							prev ${PACKAGE_ast_INCLUDE}/cdt.h
 							prev ${PACKAGE_ast_INCLUDE}/error.h
 							prev ${PACKAGE_ast_INCLUDE}/sfio.h
@@ -267,7 +263,6 @@ make install
 						prev include/nval.h
 					done include/variables.h
 					prev ${PACKAGE_ast_INCLUDE}/error.h
-					prev ${PACKAGE_ast_INCLUDE}/stak.h
 					prev include/defs.h
 					prev shopt.h
 				done bltins/cd_pwd.c
@@ -335,7 +330,6 @@ make install
 					prev include/variables.h
 					prev ${PACKAGE_ast_INCLUDE}/error.h
 					prev ${PACKAGE_ast_INCLUDE}/ls.h
-					prev ${PACKAGE_ast_INCLUDE}/stak.h
 					prev include/defs.h
 					prev shopt.h
 				done bltins/hist.c
@@ -412,7 +406,6 @@ make install
 					prev include/history.h
 					prev include/name.h
 					prev include/io.h
-					prev ${PACKAGE_ast_INCLUDE}/stak.h
 					prev ${PACKAGE_ast_INCLUDE}/error.h
 					prev include/defs.h
 					prev shopt.h
@@ -575,7 +568,6 @@ make install
 						prev ${PACKAGE_ast_INCLUDE}/sfio.h
 					done include/fcin.h
 					prev ${PACKAGE_ast_INCLUDE}/ls.h
-					prev ${PACKAGE_ast_INCLUDE}/stak.h
 					prev ${PACKAGE_ast_INCLUDE}/sfio.h
 					prev ${PACKAGE_ast_INCLUDE}/ast.h
 					prev shopt.h
@@ -634,7 +626,6 @@ make install
 			make array.o
 				make sh/array.c
 					prev include/name.h
-					prev ${PACKAGE_ast_INCLUDE}/stak.h
 					prev include/defs.h
 					prev shopt.h
 				done sh/array.c
@@ -695,7 +686,6 @@ make install
 						prev dirlib.h implicit dontcare virtual
 						prev ${PACKAGE_ast_INCLUDE}/ast_lib.h
 					done ${PACKAGE_ast_INCLUDE}/ast_dir.h
-					prev ${PACKAGE_ast_INCLUDE}/stak.h
 					prev ${PACKAGE_ast_INCLUDE}/ls.h
 					prev ${PACKAGE_ast_INCLUDE}/glob.h implicit
 					prev ${PACKAGE_ast_INCLUDE}/ast.h
@@ -786,7 +776,6 @@ make install
 					prev ${PACKAGE_ast_INCLUDE}/regex.h
 					prev ${PACKAGE_ast_INCLUDE}/tmx.h
 					prev ${PACKAGE_ast_INCLUDE}/ccode.h
-					prev ${PACKAGE_ast_INCLUDE}/stak.h
 					prev include/defs.h
 					prev shopt.h
 				done sh/init.c
@@ -840,7 +829,6 @@ make install
 					prev include/defs.h
 					prev include/nval.h
 					prev include/fcin.h
-					prev ${PACKAGE_ast_INCLUDE}/stak.h
 					prev ${PACKAGE_ast_INCLUDE}/releaseflags.h
 					prev ${PACKAGE_ast_INCLUDE}/ast.h
 					prev shopt.h
@@ -933,7 +921,6 @@ make install
 					prev include/lexstates.h
 					prev include/shtable.h
 					prev ${PACKAGE_ast_INCLUDE}/ccode.h
-					prev ${PACKAGE_ast_INCLUDE}/stak.h
 					prev include/defs.h
 					prev ${PACKAGE_ast_INCLUDE}/ast_wchar.h
 					prev ${PACKAGE_ast_INCLUDE}/ast.h
@@ -944,7 +931,6 @@ make install
 			make streval.o
 				make sh/streval.c
 					prev FEATURE/externs
-					prev ${PACKAGE_ast_INCLUDE}/stak.h
 					prev ${PACKAGE_ast_INCLUDE}/error.h
 					prev include/streval.h
 					prev shopt.h

src/cmd/ksh93/bltins/cd_pwd.c

@@ -28,7 +28,6 @@
 
 #include	"shopt.h"
 #include	"defs.h"
-#include	<stak.h>
 #include	<error.h>
 #include	"variables.h"
 #include	"path.h"
@@ -164,38 +163,37 @@ int	b_cd(int argc, char *argv[],Shbltin_t *context)
 		dp = cdpath?cdpath->name:"";
 		cdpath = path_nextcomp(cdpath,dir,0);
 #if _WINIX
-		if(*stakptr(PATH_OFFSET+1)==':' && isalpha(*stakptr(PATH_OFFSET)))
+		if(*stkptr(sh.stk,PATH_OFFSET+1)==':' && isalpha(*stkptr(sh.stk,PATH_OFFSET)))
 		{
-			*stakptr(PATH_OFFSET+1) = *stakptr(PATH_OFFSET);
-			*stakptr(PATH_OFFSET)='/';
+			*stkptr(sh.stk,PATH_OFFSET+1) = *stkptr(sh.stk,PATH_OFFSET);
+			*stkptr(sh.stk,PATH_OFFSET)='/';
 		}
 #endif /* _WINIX */
-		if(*stakptr(PATH_OFFSET)!='/')
+		if(*stkptr(sh.stk,PATH_OFFSET)!='/')
 		{
-			char *last=(char*)stakfreeze(1);
-			stakseek(PATH_OFFSET);
-			stakputs(oldpwd);
+			char *last=(char*)stkfreeze(sh.stk,1);
+			stkseek(sh.stk,PATH_OFFSET);
+			sfputr(sh.stk,oldpwd,-1);
 			/* don't add '/' if oldpwd is / itself */
 			if(*oldpwd!='/' || oldpwd[1])
-				stakputc('/');
-			stakputs(last+PATH_OFFSET);
-			stakputc(0);
+				sfputc(sh.stk,'/');
+			sfputr(sh.stk,last+PATH_OFFSET,0);
 		}
 		if(!pflag)
 		{
 			char *cp;
-			stakseek(PATH_MAX+PATH_OFFSET);
-			if(*(cp=stakptr(PATH_OFFSET))=='/')
+			stkseek(sh.stk,PATH_MAX+PATH_OFFSET);
+			if(*(cp=stkptr(sh.stk,PATH_OFFSET))=='/')
 				if(!pathcanon(cp,PATH_DOTDOT))
 					continue;
 		}
-		if((rval=chdir(path_relative(stakptr(PATH_OFFSET)))) >= 0)
+		if((rval=chdir(path_relative(stkptr(sh.stk,PATH_OFFSET)))) >= 0)
 			goto success;
 		if(errno!=ENOENT && saverrno==0)
 			saverrno=errno;
 	}
 	while(cdpath);
-	if(rval<0 && *dir=='/' && *(path_relative(stakptr(PATH_OFFSET)))!='/')
+	if(rval<0 && *dir=='/' && *(path_relative(stkptr(sh.stk,PATH_OFFSET)))!='/')
 		rval = chdir(dir);
 	/* use absolute chdir() if relative chdir() fails */
 	if(rval<0)
@@ -210,16 +208,16 @@ int	b_cd(int argc, char *argv[],Shbltin_t *context)
 		dp = dir;	/* print out directory for cd - */
 	if(pflag)
 	{
-		dir = stakptr(PATH_OFFSET);
+		dir = stkptr(sh.stk,PATH_OFFSET);
 		if (!(dir=pathcanon(dir,PATH_PHYSICAL)))
 		{
-			dir = stakptr(PATH_OFFSET);
+			dir = stkptr(sh.stk,PATH_OFFSET);
 			errormsg(SH_DICT,ERROR_system(ret),"%s:",dir);
 			UNREACHABLE();
 		}
-		stakseek(dir-stakptr(0));
+		stkseek(sh.stk,dir-stkptr(sh.stk,0));
 	}
-	dir = (char*)stakfreeze(1)+PATH_OFFSET;
+	dir = stkfreeze(sh.stk,1)+PATH_OFFSET;
 	if(*dp && (*dp!='.'||dp[1]) && strchr(dir,'/'))
 		sfputr(sfstdout,dir,'\n');
 	nv_putval(opwdnod,oldpwd,NV_RDONLY);
@@ -290,7 +288,7 @@ int	b_pwd(int argc, char *argv[],Shbltin_t *context)
 	}
 	if(flag)
 	{
-		cp = strcpy(stakseek(strlen(cp)+PATH_MAX),cp);
+		cp = strcpy(stkseek(sh.stk,strlen(cp)+PATH_MAX),cp);
 		pathcanon(cp,PATH_PHYSICAL);
 	}
 	sfputr(sfstdout,cp,'\n');

src/cmd/ksh93/bltins/enum.c

@@ -256,10 +256,8 @@ int b_enum(int argc, char** argv, Shbltin_t *context)
 			error(ERROR_exit(1), "%s must name an array containing at least two elements",cp);
 			UNREACHABLE();
 		}
-		n = staktell();
-		sfprintf(stkstd,"%s.%s%c",NV_CLASS,np->nvname,0);
-		tp = nv_open(stakptr(n), sh.var_tree, NV_VARNAME);
-		stakseek(n);
+		sfprintf(sh.strbuf,"%s.%s",NV_CLASS,np->nvname);
+		tp = nv_open(sfstruse(sh.strbuf), sh.var_tree, NV_VARNAME);
 		n = sz;
 		i = 0;
 		nv_onattr(tp, NV_UINT16);

src/cmd/ksh93/bltins/hist.c

@@ -17,7 +17,6 @@
 ***********************************************************************/
 #include	"shopt.h"
 #include	"defs.h"
-#include	<stak.h>
 #include	<ls.h>
 #include	<error.h>
 #include	"variables.h"
@@ -322,7 +321,7 @@ static void hist_subst(const char *command,int fd,char *replace)
 		return;
 	lseek(fd,0,SEEK_SET);
 	c =  (int)size;
-	string = stakalloc(c+1);
+	string = stkalloc(sh.stk,c+1);
 	if(read(fd,string,c)!=c)
 		return;
 	string[c] = 0;

src/cmd/ksh93/bltins/print.c

@@ -27,7 +27,6 @@
 #include	"shopt.h"
 #include	"defs.h"
 #include	<error.h>
-#include	<stak.h>
 #include	"io.h"
 #include	"name.h"
 #include	"history.h"
@@ -359,7 +358,7 @@ int    b_print(int argc, char *argv[], Shbltin_t *context)
 			sfprintf(outfile,"%!",&pdata);
 		} while(*pdata.nextarg && pdata.nextarg!=argv);
 		if(pdata.nextarg == nullarg && pdata.argsize>0)
-			if(sfwrite(outfile,stakptr(staktell()),pdata.argsize) < 0)
+			if(sfwrite(outfile,stkptr(sh.stk,stktell(sh.stk)),pdata.argsize) < 0)
 				exitval = 1;
 		sfpool(sfstderr,pool,SF_WRITE);
 		if (pdata.err)
@@ -424,7 +423,7 @@ static int echolist(Sfio_t *outfile, int raw, char *argv[])
 		if(!raw  && (n=fmtvecho(cp,&pdata))>=0)
 		{
 			if(n)
-				if(sfwrite(outfile,stakptr(staktell()),n) < 0)
+				if(sfwrite(outfile,stkptr(sh.stk,stktell(sh.stk)),n) < 0)
 					exitval = 1;
 		}
 		else
@@ -498,17 +497,17 @@ static char strformat(char *s)
 static char *genformat(char *format)
 {
 	char *fp;
-	stakseek(0);
-	stakputs(format);
-	fp = (char*)stakfreeze(1);
+	stkseek(sh.stk,0);
+	sfputr(sh.stk,format,-1);
+	fp = stkfreeze(sh.stk,1);
 	strformat(fp);
 	return fp;
 }
 
 static char *fmthtml(const char *string, int flags)
 {
 	const char *cp = string, *op;
-	int c, offset = staktell();
+	int c, offset = stktell(sh.stk);
 	/*
 	 * The only multibyte locale ksh currently supports is UTF-8, which is a superset of ASCII. So, if we're on an
 	 * EBCDIC system, below we attempt to convert EBCDIC to ASCII only if we're not in a multibyte locale (mbwide()).
@@ -522,19 +521,19 @@ static char *fmthtml(const char *string, int flags)
 			if(!mbwide())
 				c = CCMAPC(c,CC_NATIVE,CC_ASCII);
 			if(mbwide() && c < 0)		/* invalid multibyte char */
-				stakputc('?');
+				sfputc(sh.stk,'?');
 			else if(c == 60)		/* < */
-				stakputs("&lt;");
+				sfputr(sh.stk,"&lt;",-1);
 			else if(c == 62)		/* > */
-				stakputs("&gt;");
+				sfputr(sh.stk,"&gt;",-1);
 			else if(c == 38)		/* & */
-				stakputs("&amp;");
+				sfputr(sh.stk,"&amp;",-1);
 			else if(c == 34)		/* " */
-				stakputs("&quot;");
+				sfputr(sh.stk,"&quot;",-1);
 			else if(c == 39)		/* ' (&apos; is not HTML) */
-				stakputs("&#39;");
+				sfputr(sh.stk,"&#39;",-1);
 			else
-				stakwrite(op, cp-op);
+				sfwrite(sh.stk, op, cp-op);
 		}
 	}
 	else
@@ -545,27 +544,27 @@ static char *fmthtml(const char *string, int flags)
 			while(op = cp, c = mbchar(cp))
 			{
 				if(c < 0)
-					stakputs("%3F");
+					sfputr(sh.stk,"%3F",-1);
 				else if(c < 128 && strchr(URI_RFC3986_UNRESERVED, c))
-					stakputc(c);
+					sfputc(sh.stk,c);
 				else
 					while(c = *(unsigned char*)op++, op <= cp)
-						sfprintf(stkstd, "%%%02X", c);
+						sfprintf(sh.stk, "%%%02X", c);
 			}
 		}
 		else
 		{
 			while(c = *(unsigned char*)cp++)
 			{
 				if(strchr(URI_RFC3986_UNRESERVED, c))
-					stakputc(c);
+					sfputc(sh.stk,c);
 				else
-					sfprintf(stkstd, "%%%02X", CCMAPC(c, CC_NATIVE, CC_ASCII));
+					sfprintf(sh.stk, "%%%02X", CCMAPC(c, CC_NATIVE, CC_ASCII));
 			}
 		}
 	}
-	stakputc(0);
-	return stakptr(offset);
+	sfputc(sh.stk,0);
+	return stkptr(sh.stk,offset);
 }
 
 static ssize_t fmtbase64(Sfio_t *iop, char *string, int alt)
@@ -1013,7 +1012,7 @@ static int extend(Sfio_t* sp, void* v, Sffmt_t* fe)
 				pp->argsize = n;
 				return -1;
 			}
-			value->s = stakptr(staktell());
+			value->s = stkptr(sh.stk,stktell(sh.stk));
 			fe->size = n;
 		}
 		break;
@@ -1087,7 +1086,7 @@ static int fmtvecho(const char *string, struct printf *pp)
 {
 	const char *cp = string, *cpmax;
 	int c;
-	int offset = staktell();
+	int offset = stktell(sh.stk);
 	int chlen;
 	if(mbwide())
 	{
@@ -1107,12 +1106,12 @@ static int fmtvecho(const char *string, struct printf *pp)
 		return -1;
 	c = --cp - string;
 	if(c>0)
-		stakwrite(string,c);
+		sfwrite(sh.stk,string,c);
 	for(; c= *cp; cp++)
 	{
 		if (mbwide() && ((chlen = mbsize(cp)) > 1))
 		{
-			stakwrite(cp,chlen);
+			sfwrite(sh.stk,cp,chlen);
 			cp +=  (chlen-1);
 			continue;
 		}
@@ -1161,11 +1160,11 @@ static int fmtvecho(const char *string, struct printf *pp)
 			default:
 				cp--;
 		}
-		stakputc(c);
+		sfputc(sh.stk,c);
 	}
 done:
-	c = staktell()-offset;
-	stakputc(0);
-	stakseek(offset);
+	c = stktell(sh.stk)-offset;
+	sfputc(sh.stk,0);
+	stkseek(sh.stk,offset);
 	return c;
 }