Yet another round of accumulated tweaks and cleanups

Notable changes:

- sh/timers.c: Rename timerdel() to sh_timerdel() for consistency;
  we had timerdel() but sh_timeradd().

- include/shell.h: Remove unused sh struct members:
  - sh.lastpath (this was still being saved/restored in several
    places, but not actually used since 2008-06-02 ksh93t-)
  - sh.lastbase (unused since 2000-10-31 ksh93k)
  - sh.inpool (unused since libcoshell was removed in 3613da42)

- sh/xec.c: sh_exec(): Add comments for the various command types.

src/cmd/ksh93/bltins/cd_pwd.c

@@ -167,14 +167,13 @@ 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(*stakptr(PATH_OFFSET+1)==':' && isalpha(*stakptr(PATH_OFFSET)))
 		{
 			*stakptr(PATH_OFFSET+1) = *stakptr(PATH_OFFSET);
 			*stakptr(PATH_OFFSET)='/';
 		}
 #endif /* _WINIX */
-                if(*stakptr(PATH_OFFSET)!='/')
+		if(*stakptr(PATH_OFFSET)!='/')
-
 		{
 			char *last=(char*)stakfreeze(1);
 			stakseek(PATH_OFFSET);

src/cmd/ksh93/bltins/read.c

@@ -464,7 +464,7 @@ int sh_readline(char **names, volatile int fd, int flags, ssize_t size, long tim
 			}
 		}
 		if(timeslot)
-			timerdel(timeslot);
+			sh_timerdel(timeslot);
 		if(binary && !((size=nv_size(np)) && nv_isarray(np) && c!=size))
 		{
 			if((c==size) && np->nvalue.cp && !nv_isarray(np))
@@ -500,7 +500,7 @@ int sh_readline(char **names, volatile int fd, int flags, ssize_t size, long tim
 		}
 	}
 	if(timeslot)
-		timerdel(timeslot);
+		sh_timerdel(timeslot);
 	if((flags&S_FLAG) && !sh.hist_ptr)
 	{
 		sh_histinit();

src/cmd/ksh93/edit/edit.c

@@ -211,7 +211,7 @@ int tty_set(int fd, int action, struct termios *tty)
 /*{	TTY_COOKED( fd )
  *
  *	This routine will set the tty in cooked mode.
- *	It is also called by error.done().
+ *	It is also called by sh_done().
  *
 }*/
 

src/cmd/ksh93/edit/vi.c

@@ -193,10 +193,10 @@ static int	search(Vi_t*,int);
 static void	sync_cursor(Vi_t*);
 static int	textmod(Vi_t*,int,int);
 
-/*+	VI_READ( fd, shbuf, nchar )
+/*+	ED_VIREAD( context, fd, shbuf, nchar, reedit )
  *
  *	This routine implements a one line version of vi and is
- * called by _filbuf.c
+ * called by slowread() in io.c
  *
 -*/
 

src/cmd/ksh93/include/fault.h

@@ -124,7 +124,7 @@ extern void	sh_siginit(void);
 extern void 	sh_sigtrap(int);
 extern void 	sh_sigreset(int);
 extern void 	*sh_timeradd(unsigned long,int ,void (*)(void*),void*);
-extern void	timerdel(void*);
+extern void	sh_timerdel(void*);
 
 extern const char e_alarm[];
 

src/cmd/ksh93/include/shell.h

@@ -207,10 +207,10 @@ struct sh_scoped
 	int		ioset;
 	unsigned short	trapmax;
 	char		trapdontexec;	/* stop exec optimization if any non-DEBUG/SIGKILL/SIGSTOP trap is set and non-empty */
-	char		*trap[SH_DEBUGTRAP+1];
+	char		*trap[SH_DEBUGTRAP+1];	/* pseudosignals (except EXIT) */
-	char		**otrap;
+	char		**otrap;	/* save parent pseudosignals for v=$(trap) */
-	char		**trapcom;
+	char		**trapcom;	/* EXIT and signals */
-	char		**otrapcom;
+	char		**otrapcom;	/* save parent EXIT and signals for v=$(trap) */
 	struct Ufunction *real_fun;	/* current 'function name' function */
 	int             repl_index;
 	char            *repl_arg;
@@ -276,7 +276,6 @@ struct Shell_s
 	Sfio_t		*funlog;	/* for logging function definitions */
 	int		**fdptrs;	/* pointer to file numbers */
 	char		*lastarg;
-	char		*lastpath;	/* last absolute path found */
 	int		path_err;	/* last error on path search */
 	Dt_t		*var_base;	/* global level variables */
 	Dt_t		*fun_base;	/* global level functions */
@@ -308,7 +307,6 @@ struct Shell_s
 	unsigned char	*sigflag;	/* pointer to signal states */
 	char		intrap;
 	char		login_sh;
-	char		lastbase;
 	char		forked;
 	char		binscript;
 	char		funload;
@@ -375,7 +373,6 @@ struct Shell_s
 	Dt_t		*prev_root;
 	Dt_t		*fpathdict;
 	Dt_t		*typedict;
-	Dt_t		*inpool;
 	char		ifstable[256];
 	Shopt_t		offoptions;	/* options that were explicitly disabled by the user on the command line */
 	Shopt_t		glob_options;

src/cmd/ksh93/sh/args.c

@@ -650,7 +650,6 @@ char **sh_argbuild(int *nargs, const struct comnod *comptr,int flag)
 			*nargs = ap->dolnum;
 			return(ap->dolval+ap->dolbot);
 		}
-		sh.lastpath = 0;
 		*nargs = 0;
 		if(ac)
 		{

src/cmd/ksh93/sh/array.c

@@ -608,7 +608,6 @@ static void array_putval(Namval_t *np, const char *string, int flags, Namfun_t *
 		if(mp && mp!=np)
 		{
 			if(!is_associative(ap) && string && !(flags&NV_APPEND) && !nv_type(np) && nv_isvtree(mp) && !(ap->nelem&ARRAY_TREE))
-
 			{
 				if(!nv_isattr(np,NV_NOFREE))
 					_nv_unset(mp,flags&NV_RDONLY);

src/cmd/ksh93/sh/io.c

@@ -1607,9 +1607,7 @@ static int io_heredoc(register struct ionod *iop, const char *name, int traceon)
 		}
 		if(!(iop->iofile&IOQUOTE))
 		{
-			char *lastpath = sh.lastpath;
 			sh_machere(infile,outfile,iop->ioname);
-			sh.lastpath = lastpath;
 			if(infile)
 				sfclose(infile);
 		}
@@ -1989,7 +1987,7 @@ static ssize_t slowread(Sfio_t *iop,void *buff,register size_t size,Sfdisc_t *ha
 			timeout = (void*)sh_timeradd(sh_isstate(SH_GRACE)?1000L*TGRACE:1000L*sh.timeout,0,time_grace,&sh);
 		rsize = (*readf)(sh.ed_context, fno, (char*)buff, size, reedit);
 		if(timeout)
-			timerdel(timeout);
+			sh_timerdel(timeout);
 		timeout=0;
 #if SHOPT_HISTEXPAND
 		if(rsize && *(char*)buff != '\n' && sh.nextprompt==1 && sh_isoption(SH_HISTEXPAND))

src/cmd/ksh93/sh/name.c

@@ -2421,7 +2421,6 @@ static void table_unset(register Dt_t *root, int flags, Dt_t *oroot)
 			int len = strlen(np->nvname);
 			npnext = (Namval_t*)dtnext(root,np);
 			while((nq=npnext) && strncmp(np->nvname,nq->nvname,len)==0 && nq->nvname[len]=='.')
-
 			{
 				_nv_unset(nq,flags);
 				npnext = (Namval_t*)dtnext(root,nq);

src/cmd/ksh93/sh/nvtype.c

@@ -532,7 +532,6 @@ static void put_type(Namval_t* np, const char* val, int flag, Namfun_t* fp)
 	{
 		Namfun_t  *pp;
 		if((pp=nv_hasdisc(nq,fp->disc)) && pp->type==fp->type)
-
 		{
 			if(!nq->nvenv)
 				flag |= NV_EXPORT;

src/cmd/ksh93/sh/path.c

@@ -996,7 +996,7 @@ noreturn void path_exec(register const char *arg0,register char *argv[],struct a
 		pp=path_get(arg0);
 	sh.path_err= ENOENT;
 	sfsync(NIL(Sfio_t*));
-	timerdel(NIL(void*));
+	sh_timerdel(NIL(void*));
 	/* find first path that has a library component */
 	while(pp && (pp->flags&PATH_SKIP))
 		pp = pp->next;

src/cmd/ksh93/sh/timers.c

@@ -229,7 +229,7 @@ void *sh_timeradd(unsigned long msec,int flags,void (*action)(void*),void *handl
 /*
  * delete timer <tp>.  If <tp> is NULL, all timers are deleted
  */
-void	timerdel(void *handle)
+void	sh_timerdel(void *handle)
 {
 	register Timer_t *tp = (Timer_t*)handle;
 	if(tp)

src/cmd/ksh93/sh/xec.c

@@ -916,6 +916,9 @@ static int check_exec_optimization(int type, int execflg, int execflg2, struct i
 	return(1);
 }
 
+/*
+ * Main execution function: execute any type of command.
+ */
 int sh_exec(register const Shnode_t *t, int flags)
 {
 	Stk_t			*stkp = sh.stk;
@@ -953,9 +956,11 @@ int sh_exec(register const Shnode_t *t, int flags)
 		sh.exitval=0;
 		sh.lastsig = 0;
 		sh.chldexitsig = 0;
-		sh.lastpath = 0;
 		switch(type&COMMSK)
 		{
+		    /*
+		     * Simple command
+		     */
 		    case TCOM:
 		    {
 			register struct argnod	*argp;
@@ -1172,7 +1177,6 @@ int sh_exec(register const Shnode_t *t, int flags)
 				}
 				if(io)
 					sfsync(sh.outpool);
-				sh.lastpath = 0;
 				if(!np)
 				{
 					if(*com0 == '/' && !sh_isoption(SH_RESTRICTED))
@@ -1442,7 +1446,6 @@ int sh_exec(register const Shnode_t *t, int flags)
 						jmpval = sigsetjmp(buffp->buff,0);
 					}
 					if(jmpval == 0)
-
 					{
 						if(io)
 							indx = sh_redirect(io,execflg);
@@ -1483,6 +1486,7 @@ int sh_exec(register const Shnode_t *t, int flags)
 						siglongjmp(*sh.jmplist,jmpval);
 					goto setexit;
 				}
+				/* not a built-in or function: external command, fall through to TFORK */
 			}
 			else if(!io)
 			{
@@ -1497,6 +1501,10 @@ int sh_exec(register const Shnode_t *t, int flags)
 			}
 		    }
 		    /* FALLTHROUGH */
+
+		    /*
+		     * Any command that needs the shell to fork (e.g. background or external)
+		     */
 		    case TFORK:
 		    {
 			register pid_t parent;
@@ -1650,7 +1658,7 @@ int sh_exec(register const Shnode_t *t, int flags)
 					fd = (type&FPIN) ? 0 : 1;
 					fn = sh_open(sh.fifo,fd?O_WRONLY:O_RDONLY);
 					save_errno = errno;
-					timerdel(fifo_timer);
+					sh_timerdel(fifo_timer);
 					sh.fifo = 0;
 					if(fn<0)
 					{
@@ -1738,12 +1746,13 @@ int sh_exec(register const Shnode_t *t, int flags)
 			}
 		    }
 
-		    case TSETIO:
-		    {
 		    /*
+		     * Redirection:
 		     * don't create a new process, just
 		     * save and restore io-streams
 		     */
+		    case TSETIO:
+		    {
 			pid_t	pid = 0;
 			int 	jmpval, waitall = 0;
 			int 	simple = (t->fork.forktre->tre.tretyp&COMMSK)==TCOM;
@@ -1827,6 +1836,9 @@ int sh_exec(register const Shnode_t *t, int flags)
 			break;
 		    }
 
+		    /*
+		     * Parentheses subshell block
+		     */
 		    case TPAR:
 			echeck = 1;
 			flags &= ~OPTIMIZE_FLAG;
@@ -1861,13 +1873,13 @@ int sh_exec(register const Shnode_t *t, int flags)
 				sh_subshell(t->par.partre,flags,0);
 			break;
 
+		    /*
+		     * Pipe: command | command
+		     * All elements of the pipe are started by the parent.
+		     * The last element is executed in the current environment.
+		     */
 		    case TFIL:
 		    {
-		    /*
-		     * This code sets up a pipe.
-		     * All elements of the pipe are started by the parent.
-		     * The last element executes in current environment
-		     */
 			int	pvo[3];	/* old pipe for multi-stage */
 			int	pvn[3];	/* current set up pipe */
 			int	savepipe = pipejob;
@@ -1976,9 +1988,11 @@ int sh_exec(register const Shnode_t *t, int flags)
 			break;
 		    }
 
+		    /*
+		     * List of semicolon-separated commands
+		     */
 		    case TLST:
 		    {
-			/* a list of commands is executed here */
 			do
 			{
 				sh_exec(t->lst.lstlef,errorflg|OPTIMIZE);
@@ -1993,6 +2007,9 @@ int sh_exec(register const Shnode_t *t, int flags)
 			break;
 		    }
 
+		    /*
+		     * Logical and: command && command
+		     */
 		    case TAND:
 			if(type&TTEST)
 				skipexitset++;
@@ -2000,6 +2017,9 @@ int sh_exec(register const Shnode_t *t, int flags)
 				sh_exec(t->lst.lstrit,flags);
 			break;
 
+		    /*
+		     * Logical or: command || command
+		     */
 		    case TORF:
 			if(type&TTEST)
 				skipexitset++;
@@ -2007,7 +2027,10 @@ int sh_exec(register const Shnode_t *t, int flags)
 				sh_exec(t->lst.lstrit,flags);
 			break;
 
-		    case TFOR: /* for and select */
+		    /*
+		     * Loop: 'for' or 'select'
+		     */
+		    case TFOR:
 		    {
 			register char **args;
 			register int nargs;
@@ -2135,7 +2158,10 @@ int sh_exec(register const Shnode_t *t, int flags)
 			break;
 		    }
 
-		    case TWH: /* while and until */
+		    /*
+		     * Loop: 'while' or 'until'
+		     */
+		    case TWH:
 		    {
 			volatile int 	r=0;
 			int first = OPTIMIZE_FLAG;
@@ -2226,7 +2252,11 @@ int sh_exec(register const Shnode_t *t, int flags)
 #endif /* SHOPT_FILESCAN */
 			break;
 		    }
-		    case TARITH: /* (( expression )) */
+
+		    /*
+		     * Arithmetic command: ((expression))
+		     */
+		    case TARITH:
 		    {
 			register char *trap;
 			char *arg[4];
@@ -2252,6 +2282,9 @@ int sh_exec(register const Shnode_t *t, int flags)
 			break;
 		    }
 
+		    /*
+		     * Conditional block: if ... fi
+		     */
 		    case TIF:
 			if(sh_exec(t->if_.iftre,OPTIMIZE)==0)
 				sh_exec(t->if_.thtre,flags);
@@ -2261,6 +2294,9 @@ int sh_exec(register const Shnode_t *t, int flags)
 				sh.exitval=0; /* force zero exit for if-then-fi */
 			break;
 
+		    /*
+		     * Switch block: case ... esac
+		     */
 		    case TSW:
 		    {
 			Shnode_t *tt = (Shnode_t*)t;
@@ -2309,9 +2345,11 @@ int sh_exec(register const Shnode_t *t, int flags)
 			break;
 		    }
 
+		    /*
+		     * The 'time' keyword: time a pipeline
+		     */
 		    case TTIME:
 		    {
-			/* time the command */
 			const char *format = e_timeformat;
 			struct timeval ta, tb;
 #ifdef timeofday
@@ -2391,6 +2429,10 @@ int sh_exec(register const Shnode_t *t, int flags)
 				p_time(sfstderr,sh_translate(format),tm);
 			break;
 		    }
+
+		    /*
+		     * Function definition
+		     */
 		    case TFUN:
 		    {
 			register Namval_t *np=0;
@@ -2399,6 +2441,7 @@ int sh_exec(register const Shnode_t *t, int flags)
 			register char *cp = strrchr(fname,'.');
 			register Namval_t *npv=0,*mp;
 #if SHOPT_NAMESPACE
+			/* Namespace definition: a modified function definition */
 			if(t->tre.tretyp==TNSPACE)
 			{
 				Dt_t *root;
@@ -2572,7 +2615,9 @@ int sh_exec(register const Shnode_t *t, int flags)
 			break;
 		    }
 
-		    /* new test compound command */
+		    /*
+		     * The [[ keyword: new test compound command
+		     */
 		    case TTST:
 		    {
 			register int n;
@@ -2703,6 +2748,11 @@ int sh_exec(register const Shnode_t *t, int flags)
 	return(sh.exitval);
 }
 
+/*
+ * Public API function: run the command given by by the argument list argv,
+ * containing argn elements. If argv[0] does not contain a /, check for a
+ * built-in or function before performing a path search.
+ */
 int sh_run(int argn, char *argv[])
 {
 	register struct dolnod	*dp;
@@ -2830,7 +2880,7 @@ pid_t _sh_fork(register pid_t parent,int flags,int *jobid)
 				pause();
 			else if(forkcnt>1000L)
 				forkcnt /= 2;
-			timerdel(timeout);
+			sh_timerdel(timeout);
 			timeout = 0;
 		}
 		return(-1);
@@ -2895,7 +2945,7 @@ pid_t _sh_fork(register pid_t parent,int flags,int *jobid)
 	sh.outpipepid = ((flags&FPOU)?sh.current_pid:0);
 	if(sh.trapnote&SH_SIGTERM)
 		sh_exit(SH_EXITSIG|SIGTERM);
-	timerdel(NIL(void*));
+	sh_timerdel(NIL(void*));
 #ifdef JOBS
 	if(sh_isstate(SH_MONITOR))
 	{

src/lib/libast/port/mnt.c

@@ -2,7 +2,7 @@
 *                                                                      *
 *               This software is part of the ast package               *
 *          Copyright (c) 1985-2011 AT&T Intellectual Property          *
-*          Copyright (c) 2020-2021 Contributors to ksh 93u+m           *
+*          Copyright (c) 2020-2022 Contributors to ksh 93u+m           *
 *                      and is licensed under the                       *
 *                 Eclipse Public License, Version 1.0                  *
 *                    by AT&T Intellectual Property                     *
@@ -518,13 +518,13 @@ extern struct mntent*	getmntent(FILE*);
 
 #if _lib_getmntent
 
-typedef struct
 #if _mem_mnt_opts_mntent
 #define OPTIONS(p)	((p)->mnt_opts)
 #else
 #define OPTIONS(p)	NiL
 #endif
 
+typedef struct
 {
 	Header_t	hdr;
 	FILE*		fp;

src/lib/libast/vmalloc/vmbest.c

@@ -2,7 +2,7 @@
 *                                                                      *
 *               This software is part of the ast package               *
 *          Copyright (c) 1985-2012 AT&T Intellectual Property          *
-*          Copyright (c) 2020-2021 Contributors to ksh 93u+m           *
+*          Copyright (c) 2020-2022 Contributors to ksh 93u+m           *
 *                      and is licensed under the                       *
 *                 Eclipse Public License, Version 1.0                  *
 *                    by AT&T Intellectual Property                     *
@@ -766,7 +766,7 @@ static int bestfree(Vmalloc_t* vm, void* data, int local )
 }
 
 static void* bestresize(Vmalloc_t*	vm,		/* region allocating from	*/
-			  void*	data,		/* old block of data		*/
+			  void*		data,		/* old block of data		*/
 			  reg size_t	size,		/* new size			*/
 			  int		type,		/* !=0 to move, <0 for not copy */
 			  int		local)