simplify ${.sh.version} / $((.sh.version)) init

We don't need to determine the length of the e_version string at
runtime. Since e_version is declared as a static array, its size is
known at compile time, and the string length is a function of that,
so this is now done at compile time to save cycles on init.

This commit also removes a few tests for library functions that we
can now safely assume to be present: nice(3) and fork(2), as well
as pathnative() and pathposix() which are provided by libast
(unlike the old AT&T practice, we always compile ksh against our
shipped and known version of libast).

src/cmd/ksh93/features/externs

@@ -1,7 +1,6 @@
 hdr	nc
 mem	exception.name,_exception.name math.h
-lib	setreuid,setregid,nice,fork
-lib	pathnative,pathposix
+lib	setreuid,setregid
 lib	memcntl sys/mman.h
 
 # for main.c fixargs():

src/cmd/ksh93/include/defs.h

@@ -34,11 +34,8 @@
 #endif
 
 #include	<ast.h>
-#if !defined(AST_VERSION) || AST_VERSION < 20220801
-#error libast version 20220801 or later is required
-#endif
-#if !_lib_fork
-#error In 2021, ksh joined the 21st century and started requiring fork(2).
+#if !defined(AST_VERSION) || AST_VERSION < 20240811
+#error libast version 20240811 or later is required
 #endif
 
 #include	<sfio.h>

src/cmd/ksh93/sh/init.c

@@ -1017,17 +1017,14 @@ static char* get_version(Namval_t* np, Namfun_t *fp)
 
 static Sfdouble_t nget_version(Namval_t* np, Namfun_t *fp)
 {
-	const char	*cp = e_version + strlen(e_version)-10;
+	const char	*cp = e_version + sizeof e_version - 15;  /* version date */
 	int		c;
 	Sflong_t	t = 0;
 	NOT_USED(np);
 	NOT_USED(fp);
 	while (c = *cp++)
-		if (c >= '0' && c <= '9')
-		{
-			t *= 10;
-			t += c - '0';
-		}
+		if (isdigit(c))
+			t = 10 * t + c - '0';
 	return (Sfdouble_t)t;
 }
 
@@ -1260,13 +1257,11 @@ int sh_type(const char *path)
  */
 Shell_t *sh_init(int argc,char *argv[], Shinit_f userinit)
 {
-	size_t n;
 	int type = 0;
 	static char *login_files[2];
 	sh_onstate(SH_INIT);
-	n = strlen(e_version);
-	if(e_version[n-1]=='$' && e_version[n-2]==' ')
-		e_version[n-2]=0;
+	/* truncate final " $\0\n" from e_version for ${.sh.version} output (it's there for what(1) or ident(1)) */
+	e_version[sizeof e_version - 5] = '\0';
 	memcpy(sh_lexstates,sh_lexrstates,ST_NONE*sizeof(char*));
 	sh.current_pid = sh.pid = getpid();
 	sh.current_ppid = sh.ppid = getppid();
@@ -1327,6 +1322,7 @@ Shell_t *sh_init(int argc,char *argv[], Shinit_f userinit)
 		 */
 		char *cp=nv_getval(L_ARGNOD);
 		char buff[PATH_MAX+1];
+		size_t n;
 		sh.shpath = 0;
 		if((n = pathprog(NULL, buff, sizeof(buff))) > 0 && n <= sizeof(buff))
 			sh.shpath = sh_strdup(buff);
@@ -1390,17 +1386,15 @@ Shell_t *sh_init(int argc,char *argv[], Shinit_f userinit)
 				name = sh.st.dolv[0];
 				if(name[1]==':' && (name[2]=='/' || name[2]=='\\'))
 				{
-#if _lib_pathposix
 					char*	p;
-
+					size_t	n;
 					if((n = pathposix(name, NULL, 0)) > 0)
 					{
 						p = (char*)sh_malloc(++n);
 						pathposix(name, p, n);
 						name = p;
 					}
 					else
-#endif
 					{
 						name[1] = name[0];
 						name[0] = name[2] = '/';

src/cmd/ksh93/sh/name.c

@@ -1822,9 +1822,7 @@ void nv_putval(Namval_t *np, const char *string, int flags)
 	{
 		void *tofree=0;
 		int offset = 0;
-#if _lib_pathnative
 		char buff[PATH_MAX];
-#endif /* _lib_pathnative */
 		if(flags&NV_INTEGER)
 		{
 			if((flags&NV_DOUBLE)==NV_DOUBLE)
@@ -1852,7 +1850,6 @@ void nv_putval(Namval_t *np, const char *string, int flags)
 		}
 		if(nv_isattr(np, NV_HOST|NV_INTEGER)==NV_HOST && sp)
 		{
-#if _lib_pathnative
 			/*
 			 * return the host file name given the UNIX name
 			 */
@@ -1864,9 +1861,6 @@ void nv_putval(Namval_t *np, const char *string, int flags)
 					*buff += 'a'-'A';
 			}
 			sp = buff;
-#else
-			;
-#endif /* _lib_pathnative */
 		}
 		else if((nv_isattr(np, NV_RJUST|NV_ZFILL|NV_LJUST)) && sp)
 		{

src/cmd/ksh93/sh/xec.c

@@ -49,9 +49,6 @@
 #define _use_ntfork_tcpgrp 1
 #endif
 
-#if _lib_nice
-    extern int	nice(int);
-#endif /* _lib_nice */
 #if SHOPT_SPAWN
     static pid_t sh_ntfork(const Shnode_t*,char*[],int*,int);
 #endif /* SHOPT_SPAWN */
@@ -1535,10 +1532,8 @@ int sh_exec(const Shnode_t *t, int flags)
 				}
 				sh_offstate(SH_INTERACTIVE);
 				/* pipe in or out */
-#if _lib_nice
 				if((type&FAMP) && sh_isoption(SH_BGNICE))
 					nice(4);
-#endif /* _lib_nice */
 #if !SHOPT_DEVFD
 				if(sh.fifo && (type&(FPIN|FPOU)))
 				{

src/cmd/ksh93/tests/variables.sh

@@ -1734,5 +1734,12 @@ EOF
 wait "$parallel_1" || err_exit 'setting TMOUT in a virtual subshell removes its special meaning'
 wait "$parallel_2" || err_exit "TMOUT applies to 'read' from a non-terminal"
 
+# ======
+# TODO: fix to support > 4 year digits well before the year 10,000 :)
+got=$((.sh.version))
+exp='^[[:digit:]]{8}$'
+[[ $got =~ $exp ]] || err_exit '$((.sh.version)) does not yield YYYYMMDD digits' \
+	"(expected match of ERE $exp, got '$got')"
+
 # ======
 exit $((Errors<125?Errors:125))