From ce05175372a9ddca1a225db0765ace1127a39293 Mon Sep 17 00:00:00 2001
From: Nicholas <nbnoll@eml.cc>
Date: Fri, 12 Nov 2021 09:22:01 -0800
Subject: chore: simplified organizational structure

---
 sys/cmd/rc/exec.c | 1267 -----------------------------------------------------
 1 file changed, 1267 deletions(-)
 delete mode 100644 sys/cmd/rc/exec.c

(limited to 'sys/cmd/rc/exec.c')

diff --git a/sys/cmd/rc/exec.c b/sys/cmd/rc/exec.c
deleted file mode 100644
index 5baaf1a..0000000
--- a/sys/cmd/rc/exec.c
+++ /dev/null
@@ -1,1267 +0,0 @@
-#include "rc.h"
-#include "exec.h"
-
-#include <sys/wait.h>
-
-int yyparse(void);
-
-struct Builtin{
-	char *name;
-	void (*func)(void);
-};
-
-struct State {
-    int async;
-};
-
-static struct State state;
-
-// -----------------------------------------------------------------------
-// globals
-
-static Word nullpath = { .str="", .link=nil };
-
-struct Builtin builtin[]={
-    {"cd",    xcd},
-    {".",     xdot},
-    {"echo",  xecho},
-    {"exit",  xexit},
-    {"fg",    xfg},
-    {"jobs",  xjob},
-    0,
-};
-
-// -----------------------------------------------------------------------
-// internal
-
-/* words and lists */
-
-static
-void
-pushword(char *str)
-{
-    if(!runner->args)
-        fatal("attempt to push on empty argument stack\n");
-
-    runner->args->word = makeword(str, runner->args->word);
-}
-
-static
-void
-popword(void)
-{
-    Word *w;
-    if(!runner->args)
-        fatal("tried to pop word on empty argument stack\n");
-
-    w = runner->args->word;
-    if(!w)
-        fatal("tried to pop word but nothing there\n");
-
-    runner->args->word = w->link;
-    efree(w->str);
-    efree(w);
-}
-
-static
-Word*
-copywords(Word *a, Word *tail)
-{
-    Word *v = nil, **end;
-
-    for(end=&v; a; a = a->link,end=&(*end)->link)
-        *end = makeword(a->str, nil);
-    *end = tail;
-
-    return v;
-}
-
-static
-void
-freewords(Word *w)
-{
-    Word *n;
-    while(w){
-        efree(w->str);
-        n = w->link;
-        efree(w);
-        w = n;
-    }
-}
-
-static
-void
-freelist(Word *w)
-{
-    Word *n;
-    while(w){
-        n = w->link;
-        efree(w->str);
-        efree(w);
-        w = n;
-    }
-
-}
-
-static
-void
-pushlist(void)
-{
-    List *stack = emalloc(sizeof(*stack));
-
-    stack->word = nil;
-    stack->link = runner->args;
-
-    runner->args = stack;
-}
-
-static
-void
-poplist(void)
-{
-    List *stack = runner->args;
-    if(!stack)
-        fatal("attempted to pop an empty argument stack\n");
-
-    freelist(stack->word);
-    runner->args = stack->link;
-    efree(stack);
-}
-
-/* system interop */
-static
-Word*
-path(char *w)
-{
-    Word *path;
-
-    if(strncmp(w, "/", 1)==0
-    || strncmp(w, "./", 2)==0
-    || strncmp(w, "../", 3)==0
-    || (path = var("path")->val)==0)
-        path=&nullpath;
-
-    return path;
-}
-
-static inline
-void
-undoredirs(void)
-{
-    while(runner->redir.end != runner->redir.start)
-        Xpopredir();
-}
-
-static inline
-int
-exitsnext(void)
-{
-    Code *c = &runner->code.exe[runner->code.i];
-    while(c->f == Xpopredir)
-        c++;
-
-    return c->f == Xexit;
-}
-
-static inline
-void
-defaultsignal(void)
-{
-    signal(SIGINT,  SIG_DFL);
-    signal(SIGQUIT, SIG_DFL);
-    signal(SIGTSTP, SIG_DFL);
-    signal(SIGTTIN, SIG_DFL);
-    signal(SIGTTOU, SIG_DFL);
-    signal(SIGCHLD, SIG_DFL);
-}
-
-static inline
-void
-setpid(Thread *job, int pid)
-{
-    job->pid = pid;
-    if(job->pgid <= 0){
-        job->pgid = pid;
-        addjob(job);
-    }
-
-    setpgid(pid, job->pgid);
-}
-
-/* fork/execute helpers */
-
-static inline
-void
-initchild(Thread *job, int fg)
-{
-    int pid = getpid();
-    setpid(job, pid);
-
-    if(job->flag.user){
-        if(fg)
-            tcsetpgrp(0, job->pgid);
-        else
-            job->flag.user = 0;
-        defaultsignal();
-    }
-
-    clearwait(job);
-}
-
-static inline
-void
-initparent(Thread *job, int pid, int fg)
-{
-    setpid(job, pid);
-
-    if(job->flag.user){
-        if(!fg){
-            tcsetpgrp(0, job->pgid);
-            job->flag.user = 0;
-        }
-    }
-    addwait(job, pid);
-}
-
-static
-void
-xx(void)
-{
-    popword(); // "exec"
-    if(!runner->args->word){
-        Xerror("empty argument list");
-        return;
-    }
-
-    redirect(runner->redir.end);
-    execute(runner->args->word, path(runner->args->word->str));
-    poplist();
-}
-
-static
-int
-xforkx(void)
-{
-    int n, pid;
-
-    switch(pid=fork()){
-    case -1:
-        Xerror("try again\n");
-        return -1;
-    case 0: // child
-        initchild(runner, 1);
-
-        pushword("exec");
-        xx();
-
-        exit(2); // NOTE: unreachable: xx does not return
-    default: // parent
-        initparent(runner, pid, 0);
-
-        return pid;
-    }
-}
-
-/* redirections */
-void
-pushredir(int type, int from, int to)
-{
-    Redir *r = emalloc(sizeof(*r));
-
-    r->type = type;
-    r->from = from;
-    r->to = to;
-
-    r->link = runner->redir.end, runner->redir.end = r;
-}
-
-/* byte code */
-static
-void
-run(Code *c, int pc, Var *local, int inherit)
-{
-    Thread *new = emalloc(sizeof(*new));
-
-    new->code.i   = pc;
-    new->code.exe = copycode(c);
-
-    new->cmd.path = nil;
-    new->cmd.io   = nil;
-
-    new->args     = nil;
-    new->local    = local;
-
-    new->flag.eof  = 0;
-    if(runner){
-        new->pid       = runner->pid;
-        new->flag.user = runner->flag.user;
-        new->redir.end = new->redir.start = runner->redir.end;
-    }else{
-        new->pid       = shell.pid;
-        new->flag.user = shell.interactive;
-        new->redir.end = new->redir.start = nil;
-    }
-
-    new->wait.status = 0;
-    new->wait.len    = 0;
-    new->wait.cap    = 0;
-    new->wait.on     = nil;
-
-    new->status = 0;
-    if(inherit)
-        new->pgid = runner->pgid;
-    else
-        new->pgid = -1;
-
-    new->line     = 0;
-    new->caller   = runner;
-    new->link     = nil;
-
-    runner = new;
-}
-
-// -----------------------------------------------------------------------
-// exported builtins
-
-// XXX: find a better place for these
-Word*
-makeword(char *str, Word *link)
-{
-    Word *w = emalloc(sizeof(*w));
-
-    w->str  = strdup(str);
-    w->link = link;
-
-    return w;
-}
-
-void
-freeword(Word *word)
-{
-    Word *n;
-
-    while(word){
-        efree(word->str);
-        n = word->link;
-        efree(word);
-        word = n;
-    }
-}
-
-int
-count(Word *w)
-{
-    int n;
-    for(n = 0; w; n++)
-        w = w->link;
-    return n;
-}
-
-// -----------------------------------------------------------------------
-// builtins
-
-void
-xecho(void)
-{
-    int  fd;
-    Word *arg;
-    char *b, *s, buf[128];
-
-    fd = mapfd(1);
-    b  = buf;
-
-    popword(); // echo
-
-    // TODO: controllable flags here
-    arg = runner->args->word;
-printword:
-    s = arg->str;
-    while(*s){
-        *b++ = *s++;
-        if(b == arrend(buf)-2) // always have 2 bytes available
-            write(fd, buf, arrlen(buf)-2), b = buf;
-    }
-
-    arg = arg->link;
-    if(arg){
-        *b++ = ' ';
-        goto printword;
-    }else{
-        *b++ = '\n';
-        *b++ = 0;
-        /* fallthrough */
-    }
-    write(fd, buf, b-buf);
-
-    poplist();
-}
-
-void
-xexit(void)
-{
-    Word *arg;
-
-    popword(); // exit
-    arg = runner->args->word;
-    switch(count(arg)){
-    default:
-        print(shell.err, "invalid number of arguments to exit, exiting anyways\n");
-    case 0:
-        Xexit();
-    }
-    /* unreachable */
-}
-
-void
-xcd(void)
-{
-    Word *arg;
-    Word *cdpath;
-    char dir[512];
-
-    popword(); // cd
-
-    arg = runner->args->word;
-    switch(count(arg)){
-    default:
-        print(shell.err, "usage: cd [directory]\n");
-        break;
-    case 0:
-        arg = var("home")->val;
-        if(count(arg) >= 1){
-            if(chdir(arg->str) < 0)
-                print(shell.err, "failed cd: %s\n", strerror(errno));
-        }else{
-            print(shell.err, "ambiguous cd: $home empty\n");
-        }
-        break;
-
-    case 1:
-        // TODO: add cdpath
-        cdpath = &nullpath;
-        for(; cdpath; cdpath = cdpath->link){
-            strcpy(dir, cdpath->str);
-            if(dir[0])
-                strcat(dir,"/");
-            strcat(dir, arg->str);
-            if(chdir(dir) < 0){
-                print(shell.err, "failed cd %s: %s\n", dir, strerror(errno));
-            }
-            break;
-        }
-        break;
-    }
-
-    poplist();
-}
-
-static Code dotcmd[14] =
-{
-    [0]  = {.i = 0},
-    [1]  = {.f = Xmark},
-    [2]  = {.f = Xword},
-    [3]  = {.s = "0"},
-    [4]  = {.f =  Xlocal},
-    [5]  = {.f =  Xmark},
-    [6]  = {.f =  Xword},
-    [7]  = {.s = "*"},
-    [8]  = {.f =  Xlocal},
-    [9]  = {.f =  Xreadcmd},
-    [10] = {.f =  Xunlocal},
-    [11] = {.f =  Xunlocal},
-    [12] = {.f =  Xreturn},
-};
-
-void
-xdot(void)
-{
-    Word *p;
-    List *argv;
-    char *base;
-    int fd, iflag = 0;
-    Thread *old;
-    char file[512];
-
-    popword(); // "."
-#if 0
-    if(proc->args->word && strcmp(proc->args->word->str, "-i")==0){
-        iflag = 1;
-        popword();
-    }
-#endif
-    /* get input file */
-    if(!runner->args->word){
-        Xerror("usage: . [-i] file [arg ...]\n");
-        return;
-    }
-
-    base = strdup(runner->args->word->str);
-    popword();
-    for(fd=-1, p=path(base); p; p = p->link){
-        strcpy(file, p->str);
-
-        if(file[0])
-            strcat(file, "/");
-        strcat(file, base);
-
-        if((fd = open(file, 0))>=0)
-            break;
-    }
-
-    if(fd<0){
-        print(shell.err, "failed open: %s: ", base);
-        return;
-    }
-    /* set up for a new command loop */
-    old = runner; // store pointer to old code
-    run(dotcmd, 1, nil, 0);
-
-    /* operations on new command stack */
-    pushredir(Rclose, fd, 0);
-    runner->cmd.path = base;
-    runner->cmd.io   = openfd(fd);
-
-    /* push $* value */
-    pushlist();
-    runner->args->word = old->args->word;
-
-    /* free caller's copy of $* */
-    argv = old->args;
-    old->args = argv->link;
-    efree(argv);
-
-    /* push $0 value */
-    pushlist();
-    pushword(base);
-    //ndot++;
-}
-
-void
-xjob(void)
-{
-    int i;
-    Thread *job;
-
-    for(i=0, job = shell.jobs; job; job = job->link, i++)
-        report(job,i);
-
-    poplist();
-}
-
-void
-xfg(void)
-{
-    int     i;
-    Thread *job, *old;
-
-    popword(); // fg
-
-    /* get input job id */
-    if(!runner->args->word){
-        print(shell.err, "usage: fg [pid|\%num]\n");
-        poplist();
-        return;
-    }
-
-    i = atoi(runner->args->word->str);
-    popword(); // [pid|num]
-
-    for(job=shell.jobs; i > 0; job=job->link, --i)
-        ;
-
-    poplist(); // this goes here?
-
-    wakeup(job);
-    job->caller = runner, runner = job; // XXX: can this leave zombies?
-    foreground(job, 1);
-}
-
-void
-xboot(int argc, char *argv[])
-{
-    int i;
-    Code bootstrap[32];
-    char num[12];
-
-    i = 0;
-    bootstrap[i++].i = 1;
-    bootstrap[i++].f = Xmark;
-    bootstrap[i++].f = Xword;
-    bootstrap[i++].s="*";
-    bootstrap[i++].f = Xassign;
-    bootstrap[i++].f = Xmark;
-    bootstrap[i++].f = Xmark;
-    bootstrap[i++].f = Xword;
-    bootstrap[i++].s="*";
-    bootstrap[i++].f = Xdollar;
-    bootstrap[i++].f = Xword;
-    bootstrap[i++].s = "/dev/stdin";
-    bootstrap[i++].f = Xword;
-    bootstrap[i++].s=".";
-    bootstrap[i++].f = Xbasic;
-    bootstrap[i++].f = Xexit;
-    bootstrap[i].i = 0;
-
-    run(bootstrap, 1, nil, 0);
-    runner->pid = runner->pgid = shell.pid;
-    pushlist(); // prime bootstrap argv
-
-    argv0 = strdup(argv[0]);
-    for(i = argc-1; i > 0; --i)
-        pushword(argv[i]);
-
-    /* main interpreter loop */
-    for(;;){
-        runner->code.i++;
-        (*runner->code.exe[runner->code.i-1].f)();
-    }
-}
-
-// -----------------------------------------------------------------------
-// exported interpreter bytecode
-
-void
-Xmark(void)
-{
-    pushlist();
-}
-
-void
-Xword(void)
-{
-    pushword(runner->code.exe[runner->code.i++].s);
-}
-
-void
-Xtrue(void)
-{
-    if(!runner->status){
-        assert(runner->wait.status == Pdone);
-        runner->code.i++;
-        deljob(runner);
-        runner->pgid = -1;
-    }else
-        runner->code.i = runner->code.exe[runner->code.i].i;
-}
-
-void
-Xfalse(void)
-{
-    if(runner->status){
-        assert(runner->wait.status == Pdone);
-        runner->code.i++;
-        deljob(runner);
-        runner->pgid = -1;
-    } else
-        runner->code.i = runner->code.exe[runner->code.i].i;
-}
-
-void
-Xgoto(void)
-{
-    runner->code.i = runner->code.exe[runner->code.i].i;
-}
-
-void
-Xfor(void)
-{
-    if(!runner->args->word){
-        poplist();
-        runner->code.i = runner->code.exe[runner->code.i].i;
-    }else{
-        freelist(runner->local->val);
-
-        runner->local->val = runner->args->word;
-        runner->local->new = 1;
-        runner->args->word = runner->args->word->link;
-
-        runner->local->val->link = nil;
-        runner->code.i++;
-    }
-
-}
-
-static
-Word*
-catlist(Word *l, Word *r, Word *tail)
-{
-    Word *w;
-    char *buf;
-
-    if(l->link || r->link)
-        tail = catlist( (!l->link)?l:l->link, (!r->link)?r:r->link, tail);
-
-    buf = emalloc(strlen(l->str)+strlen(r->str)+1);
-    strcpy(buf, l->str);
-    strcat(buf, r->str);
-
-    w = makeword(buf, tail);
-    efree(buf);
-
-    return w;
-}
-
-void
-Xconcatenate(void)
-{
-    int rn, ln;
-    Word *l = runner->args->word;
-    Word *r = runner->args->link->word;
-    Word *w = runner->args->link->link->word;
-
-    ln = count(l), rn = count(r);
-    if(ln != 0 || rn != 0) {
-        if(ln == 0 || rn == 0){
-            Xerror("null list in concatenation\n");
-            return;
-        }
-        if(ln != 1 && rn != 1 && ln != rn) {
-            Xerror("mismatched list lengths in concatenation\n");
-            return;
-        }
-        w = catlist(l, r, w);
-    }
-
-    poplist();
-    poplist();
-    runner->args->word = w;
-}
-
-void
-Xdollar(void)
-{
-    int n;
-    char *s, *t;
-    Word *a, *star;
-
-    if(count(runner->args->word)!=1){
-        Xerror("variable name not singleton!\n");
-        return;
-    }
-    s = runner->args->word->str;
-    // deglob(s);
-    n = 0;
-
-    for(t = s;'0'<=*t && *t<='9';t++) 
-        n = n*10+*t-'0';
-
-    a = runner->args->link->word;
-
-    if(n==0 || *t)
-        a = copywords(var(s)->val, a);
-    else{
-        star = var("*")->val;
-        if(star && 1<=n && n<=count(star)){
-            while(--n)
-                star = star->link;
-
-            a = makeword(star->str, a);
-        }
-    }
-
-    poplist();
-    runner->args->word = a;
-}
-
-static
-Word*
-cpwords(Word *array, Word *tail, int n)
-{
-    Word *cp, **end;
-
-    cp = nil, end = &cp;
-    while(n-- > 0){
-        *end = makeword(array->str, nil);
-        end = &(*end)->link;
-        array = array->link;
-    }
-    *end = tail;
-
-    return cp;
-}
-
-
-static
-Word*
-getindex(Word *array, int len, Word *index, Word *tail)
-{
-    char *s;
-    int n, m;
-    if(!index)
-        return tail;
-
-    tail = getindex(array, len, index->link, tail);
-
-    s = index->str;
-    //deglob(s)
-
-    m = 0, n = 0;
-    while('0' <= *s && *s <= '9')
-        n = 10*n + (*s++ - '0');
-    if(*s == '-'){
-        if(*++s == 0)
-            m = len - n;
-        else{
-            while('0' <= *s && *s <= '9')
-                m = 10*m + (*s++ - '0');
-            m -= n;
-        }
-    }
-
-    if(n<1 || n > len || m < 0)
-        return tail;
-    if(n+m > len)
-        m = len-n;
-    while(--n > 0)
-        array = array->link;
-    return cpwords(array, tail, m+1);
-}
-
-void
-Xindex(void)
-{
-    char *s;
-    Word *val, *ret;
-
-    if(count(runner->args->word) != 1){
-        Xerror("variable name not a singleton");
-        return;
-    }
-    s = runner->args->word->str;
-    //deglob(s)
-    val = var(s)->val;
-    poplist();
-
-    ret = runner->args->link->word; // pointer to next stack frame
-    ret = getindex(val, count(val), runner->args->word, ret);
-    poplist();
-
-    // push result back on stack
-    runner->args->word = ret;
-}
-
-void
-Xjoin(void)
-{
-    int  n;
-    char *s;
-    Word *arg, *elt;
-
-    if(count(runner->args->word) != 1){
-        Xerror("variable name is not singleton\n");
-        return;
-    }
-
-    s = runner->args->word->str;
-    // deglob(s)
-
-    arg = var(s)->val;
-    poplist();
-
-    n = count(arg);
-    if(n==0){
-        pushword("");
-        return;
-    }
-
-    for(elt = arg; elt; elt=elt->link)
-        n += strlen(elt->str);
-
-    s = emalloc(n);
-    if(arg){
-        strcpy(s, arg->str);
-        for(elt = arg->link; elt; elt = elt->link){
-            strcat(s, " ");
-            strcat(s, elt->str);
-        }
-    }else
-        s[0] = 0;
-
-    pushword(s);
-    efree(s);
-}
-
-void
-Xassign(void)
-{
-    Var *v;
-
-    if(count(runner->args->word)!=1){
-        Xerror("variable name not singleton!\n");
-        return;
-    }
-    //deglob(runq->argv->words->word);
-    v = var(runner->args->word->str);
-    poplist();
-
-    //globlist();
-    freewords(v->val);
-    v->val = runner->args->word;
-    v->new = 1;
-    if(v->update)
-        v->update(v);
-
-    runner->args->word = nil;
-    poplist();
-}
-
-void
-Xreadcmd(void)
-{
-    Thread *root;
-    Word *prompt;
-
-    flush(shell.err);
-    root = runner;
-
-    resetprompt();
-
-    if(yyparse()){
-        // resource cleanup?
-        if(runner->flag.eof)
-            Xreturn();
-        else
-            --root->code.i;
-    }else{
-        --root->code.i;    /* re-execute Xreadcmd after codebuf runs */
-        run(compiled, 1, root->local, 0);
-    }
-
-    killzombies();
-    freeparsetree();
-}
-
-void
-Xlocal(void)
-{
-    if(count(runner->args->word)!=1){
-        Xerror("variable name must be singleton\n");
-        return;
-    }
-    //deglob(shell->args->word->str);
-
-    runner->local      = makevar(strdup(runner->args->word->str), runner->local);
-    runner->local->val = copywords(runner->args->link->word, nil);
-    runner->local->new = 1;
-
-    poplist();
-    poplist();
-}
-
-void
-Xunlocal(void)
-{
-    Var *v = runner->local, *hide;
-    if(!v)
-        fatal("Xunlocal: no locals!\n", 0);
-
-    runner->local = v->link;
-    hide = var(v->name);
-    hide->new = 1;
-
-    efree(v->name);
-    freewords(v->val);
-    efree(v);
-}
-
-void
-Xasync(void)
-{
-    int pid;
-    /*
-    int null = open("/dev/null", 0);
-    if(!null){
-        Xerror("can not open /dev/null\n");
-        return;
-    }
-    */
-
-    switch(pid=fork()){
-    case -1:
-        // close(null);
-        Xerror("fork failed: try again");
-        break;
-
-    case 0: // child in background
-        initchild(runner,0);
-        /* pushredir(Ropen, null, 0); */
-
-        run(runner->code.exe, runner->code.i+1, runner->local, 0);
-        runner->caller = nil;
-        runner->flag.user = 0;
-        break;
-
-    default: // parent in foreground
-        initparent(runner,pid,1);
-        // close(null);
-
-        runner->code.i = runner->code.exe[runner->code.i].i; /* jump to end of async command */
-        /* don't wait: continue running */
-    }
-}
-
-void
-Xsubshell(void)
-{
-    int pid, user;
-
-    user = runner->flag.user;
-    switch(pid=fork()){
-    case -1:
-        Xerror("fork failed: try again");
-        break;
-
-    case 0: // child
-        initchild(runner, 1);
-        run(runner->code.exe, runner->code.i+1, runner->local, 1);
-        runner->caller = nil;
-        break;
-
-    default: // parent
-        initparent(runner, pid, 0); // relinquish control
-        waitfor(runner, pid);       // wait until child finishes
-        if(user){
-            tcsetpgrp(0, shell.pid);
-            runner->flag.user = 1;  // take control
-        }
-
-        runner->code.i = runner->code.exe[runner->code.i].i; // jump to end of subshell command and continue execution
-    }
-}
-
-void
-Xpipewait(void)
-{
-    foreground(runner, 0);
-}
-
-void
-Xpipe(void)
-{
-    Thread *orig;
-    int pc, pid, lfd, rfd, pfd[2];
-
-    orig = runner;
-    pc   = orig->code.i;
-    lfd  = orig->code.exe[pc++].i;
-    rfd =  orig->code.exe[pc++].i;
-
-    if(pipe(pfd)<0){
-        Xerror("can't get pipe\n");
-        return;
-    }
-
-    switch(pid=fork()){
-    case -1:
-        Xerror("try again");
-        break;
-    case 0:  // child
-        initchild(runner,1);
-
-        /* child 0 (writer) forked process */
-        run(runner->code.exe, pc+2, runner->local, 1);
-        runner->caller = nil;
-
-        close(pfd[0]);
-        pushredir(Ropen, pfd[1], lfd);
-        break;
-
-    default: // parent
-        initparent(runner,pid,0);
-
-        /* child 1 (reader) subprocess*/
-        run(runner->code.exe, runner->code.exe[pc].i, runner->local, 1);
-
-        close(pfd[1]);
-        pushredir(Ropen, pfd[0], rfd);
-
-        orig->code.i = orig->code.exe[pc+1].i;
-        break;
-    }
-}
-
-void
-Xbasic(void)
-{
-    Var  *v;
-    Word *arg;
-    int pid, status;
-    struct Builtin *b;
-
-    arg = runner->args->word;
-    if(!arg){
-        Xerror("empty argument list\n");
-        return;
-    }
-
-    v = var(arg->str);
-    if(v->func){
-        return;
-    }
-
-    // see if it matches a builtin
-    for(b = builtin; b->name; b++){
-        if(strcmp(b->name, arg->str)==0){
-            b->func();
-            return;
-        }
-    }
-
-    /* if we are here then it's an external command */
-    if(exitsnext()){ // if we exit immediately, no need to fork
-        pushword("exec");
-        xx();
-        Xexit();
-    }
-
-    // run the external command
-    if((pid = xforkx()) < 0) {
-        Xerror("try again");
-        return;
-    }
-
-    poplist();
-    foreground(runner, 0); // waits for child
-}
-
-void
-Xcount(void)
-{
-    Word *arg;
-    char *str, num[12];
-
-    if(count(runner->args->word) != 1){
-        Xerror("variable name not a singleton\n");
-        return;
-    }
-
-    str = runner->args->word->str;
-    arg = var(str)->val;
-    poplist();
-
-    itoa(num, count(arg));
-    pushword(num);
-}
-
-void
-Xflat(void)
-{
-    int   len;
-    char *str;
-    Word *arg, *a;
-
-    if(count(runner->args->word)!=1){
-        Xerror("variable name is not a singleton\n");
-        return;
-    }
-
-    str = runner->args->word->str;
-    arg = var(str)->val;
-    poplist();
-
-    len = count(arg);
-    if(!len){
-        pushword("");
-        return;
-    }
-
-    for(a=arg; a; a=a->link)
-        len += strlen(a->str);
-
-    str = emalloc(len);
-    if(arg){
-        strcpy(str, arg->str);
-        for(a = arg->link; a; a = a->link){
-            strcat(str," ");
-            strcat(str,a->str);
-        }
-    }else
-        str[0] = 0;
-
-    pushword(str);
-    efree(str);
-}
-
-void
-Xbang(void)
-{
-    if(runner->status)
-        runner->status = 0;
-    else
-        runner->status = 1;
-}
-
-void
-Xpopredir(void)
-{
-    Redir *r = runner->redir.end;
-    if(!r)
-        fatal("attempted to pop a nil redir\n");
-
-    runner->redir.end = runner->redir.end->link;
-    if(r->type==Ropen)
-        close(r->from);
-
-    efree(r);
-}
-
-void
-Xreturn(void)
-{
-    Thread *curr = runner;
-
-    switch(curr->wait.status){
-    /*
-     * If our job is still running or suspended we must:
-     * 1. move program one step back to rerun Xreturn upon recall
-     * 2. return to our calling thread
-     * 3. don't free!
-     */
-     case Prun:
-         report(curr, 0);
-         curr->flag.user = 0;
-     case Pstop:
-        curr->code.i--;
-        runner = curr->caller;
-        curr->caller = nil; // detach job
-        return;
-    /*
-     * If our job has finished:
-     * 1. remove from our list
-     * 2. continue to clean up its memory
-     */
-    case Pdone:
-        deljob(curr);
-        /* fallthrough */
-    default:
-        ;
-    }
-
-    undoredirs();
-
-    while(curr->args)
-        poplist();
-    freecode(curr->code.exe);
-    efree(curr->wait.on);
-
-    runner = curr->caller;
-    efree(curr);
-    if(!runner)
-        exit(0);
-}
-
-void
-Xexit(void)
-{
-    exit(runner->status);
-}
-
-void
-Xerror(char *msg)
-{
-    print(shell.err, "rc: %s", msg);
-    flush(shell.err);
-    while(!runner->flag.user)
-        Xreturn();
-}
-
-- 
cgit v1.2.1