From e923adef5df8077259ed9973a4bffb0e08999fbe Mon Sep 17 00:00:00 2001
From: Nicholas Noll <nbnoll@eml.cc>
Date: Tue, 16 Nov 2021 14:46:55 -0800
Subject: chore: integrated redir code

---
 src/cmd/rc/code.c   |  10 ++++-
 src/cmd/rc/exec.c   | 112 ++++++++++++++++++++++++++++++++++++++++++----------
 src/cmd/rc/exec.h   |   1 +
 src/cmd/rc/job.c    |   3 ++
 src/cmd/rc/lex.c    |   2 +
 src/cmd/rc/parse.c  |   2 +-
 src/cmd/rc/rc.h     |   1 +
 src/cmd/rc/syntax.y |   2 +-
 src/cmd/rc/sys.c    |   9 +++--
 src/cmd/rc/tree.c   |  19 +++++++++
 src/cmd/rc/var.c    |   2 +-
 11 files changed, 135 insertions(+), 28 deletions(-)

(limited to 'src/cmd')

diff --git a/src/cmd/rc/code.c b/src/cmd/rc/code.c
index dd0e99c..748c964 100644
--- a/src/cmd/rc/code.c
+++ b/src/cmd/rc/code.c
@@ -164,7 +164,7 @@ walk(Tree *node)
         break;
 
     case '=':
-        for(n=node; node && node->type == '='; node = node->child[2])
+        for(n=node; node && node->type == '='; node=node->child[2])
             ;
         if(node){
             for(node=n; node->type=='='; node = node->child[2]){
@@ -317,6 +317,14 @@ walk(Tree *node)
         storepc(addr1);
         break;
 
+    case '`':
+        emitf(Xsubcmd);
+        addr1 = emiti(0);
+        walk(node->child[0]);
+        emitf(Xexit);
+        storepc(addr1);
+        break;
+
     case Tpipe:
         emitf(Xpipe);
 
diff --git a/src/cmd/rc/exec.c b/src/cmd/rc/exec.c
index 28b6135..28941a0 100644
--- a/src/cmd/rc/exec.c
+++ b/src/cmd/rc/exec.c
@@ -168,8 +168,7 @@ undoredirs(void)
         Xpopredir();
 }
 
-static inline
-int
+static inline int
 exitsnext(void)
 {
     Code *c = &runner->code.exe[runner->code.i];
@@ -191,8 +190,7 @@ defaultsignal(void)
     signal(SIGCHLD, SIG_DFL);
 }
 
-static inline
-void
+static inline void
 setpid(Thread *job, int pid)
 {
     job->pid = pid;
@@ -206,8 +204,7 @@ setpid(Thread *job, int pid)
 
 /* fork/execute helpers */
 
-static inline
-void
+static inline void
 initchild(Thread *job, int fg)
 {
     int pid = getpid();
@@ -224,8 +221,7 @@ initchild(Thread *job, int fg)
     clearwait(job);
 }
 
-static inline
-void
+static inline void
 initparent(Thread *job, int pid, int fg)
 {
     setpid(job, pid);
@@ -239,8 +235,7 @@ initparent(Thread *job, int pid, int fg)
     addwait(job, pid);
 }
 
-static
-void
+static void
 xx(void)
 {
     popword(); // "exec"
@@ -248,32 +243,29 @@ xx(void)
         Xerror("empty argument list");
         return;
     }
-
+    // set up file descriptors
     redirect(runner->redir.end);
     execute(runner->args->word, path(runner->args->word->str));
     poplist();
 }
 
-static
-int
+static int
 xforkx(void)
 {
     int n, pid;
 
     switch(pid=fork()){
     case -1:
-        Xerror("try again\n");
+        Xerror("fork failed: try again\n");
         return -1;
     case 0: // child
         initchild(runner, 1);
-
         pushword("exec");
         xx();
-
-        exit(2); // NOTE: unreachable: xx does not return
+        exit(2); // reach here on failed execs
+        break;
     default: // parent
         initparent(runner, pid, 0);
-
         return pid;
     }
 }
@@ -286,7 +278,7 @@ pushredir(int type, int from, int to)
 
     r->type = type;
     r->from = from;
-    r->to = to;
+    r->to   = to;
 
     r->link = runner->redir.end, runner->redir.end = r;
 }
@@ -1080,7 +1072,7 @@ Xjoin(void)
     }
 
     s = runner->args->word->str;
-    // deglob(s)
+    deglob(s);
 
     arg = var(s)->val;
     poplist();
@@ -1282,6 +1274,86 @@ Xsubshell(void)
     }
 }
 
+void
+Xsubcmd(void)
+{
+    Io *io;
+    rune r;
+    Var *ifs;
+    Word *w, *nw;
+    int n, c, pid, pfd[2];
+    char *s, *end, *hit, *q, buf[8193];
+
+    ifs = var("ifs");
+    end = arrend(buf)-1;
+    hit = ifs->val ? ifs->val->str : "";
+
+    if(pipe(pfd)<0){
+        Xerror("pipe failed");
+        return;
+    }
+
+    switch(pid=fork()){
+    case -1:
+        Xerror("fork failed: try again");
+        close(pfd[0]), close(pfd[1]);
+        return;
+
+    case 0:  // child
+        initchild(runner, 1);
+
+        close(pfd[0]);
+        run(runner->code.exe, runner->code.i+1, runner->local, 1);
+        pushredir(Ropen, pfd[1], 1);
+        break;
+
+    default: // parent
+        initparent(runner, pid, 0);
+        close(pfd[1]);
+        io = openfd(pfd[0]);
+
+        s = buf;
+        w = nil;
+        while((c=get(io))!=EOF){
+            if(s != end){
+                *s++ = c;
+                for(q=hit; *q; q+=n){
+                    n = utf8·decode(q, &r);
+                    if(s-buf >= n && memcmp(s-n, q, n)==0){
+                        s -= n;
+                        goto finish;
+                    }
+                }
+                continue;
+            }
+        finish:
+            if(s != buf){
+                *s = 0;
+                w = makeword(buf, w);
+            }
+            s = buf;
+        }
+        if(s != buf){
+            *s = 0;
+            w = makeword(buf, w);
+        }
+
+        waitfor(runner, pid);
+        terminate(io);
+
+        /* reverse the list */
+        while(w){
+            nw = w->link;
+            w->link = runner->args->word;
+            runner->args->word = w;
+            w = nw;
+        }
+        assert(runner->wait.status == Pdone);
+        deljob(runner);
+        runner->code.i = runner->code.exe[runner->code.i].i;
+    }
+}
+
 void
 Xpipewait(void)
 {
diff --git a/src/cmd/rc/exec.h b/src/cmd/rc/exec.h
index 9db7e60..d7eee73 100644
--- a/src/cmd/rc/exec.h
+++ b/src/cmd/rc/exec.h
@@ -8,6 +8,7 @@
  */
 
 void Xnewpgid(void);
+void Xsubcmd(void);
 void Xunmark(void);
 void Xwrite(void);
 void Xread(void);
diff --git a/src/cmd/rc/job.c b/src/cmd/rc/job.c
index 1587951..3a53365 100644
--- a/src/cmd/rc/job.c
+++ b/src/cmd/rc/job.c
@@ -88,4 +88,7 @@ deljob(Thread *job)
         ;
 
     *jp = job->link;
+    // XXX: I think this is mandatory hygeine
+    job->status = Pnil;
+    job->pgid = job->pid = -1;
 }
diff --git a/src/cmd/rc/lex.c b/src/cmd/rc/lex.c
index 0eb023c..a22dc7d 100644
--- a/src/cmd/rc/lex.c
+++ b/src/cmd/rc/lex.c
@@ -529,6 +529,8 @@ yylex(void)
             *w = 0;
         node = token(Tword, lexer.buf);
         node->quoted = 1;
+
+        yylval.tree = node;
         return node->type;
 
     default:
diff --git a/src/cmd/rc/parse.c b/src/cmd/rc/parse.c
index 7ff860e..6a08f17 100644
--- a/src/cmd/rc/parse.c
+++ b/src/cmd/rc/parse.c
@@ -1651,7 +1651,7 @@ yyreduce:
 
   case 25: /* cmd: basic  */
 #line 87 "src/cmd/rc/syntax.y"
-                                                { (yyval.tree) = maketree1(Tbasic, (yyvsp[0].tree)); }
+                                                { (yyval.tree) = basictree((yyvsp[0].tree)); }
 #line 1656 "src/cmd/rc/parse.c"
     break;
 
diff --git a/src/cmd/rc/rc.h b/src/cmd/rc/rc.h
index 720c6f2..f5c8a6d 100644
--- a/src/cmd/rc/rc.h
+++ b/src/cmd/rc/rc.h
@@ -217,6 +217,7 @@ Tree *maketree(void);
 Tree *maketree1(int, Tree*);
 Tree *maketree2(int, Tree*, Tree*);
 Tree *maketree3(int, Tree*, Tree*, Tree*);
+Tree *basictree(Tree*);
 
 Tree *token(int, char *);
 Tree *hangchild1(Tree *, Tree *, int);
diff --git a/src/cmd/rc/syntax.y b/src/cmd/rc/syntax.y
index 4acd92f..36e1dad 100644
--- a/src/cmd/rc/syntax.y
+++ b/src/cmd/rc/syntax.y
@@ -84,7 +84,7 @@ epilog:
 
 cmd:
 /* empty */  %prec Twhile                       { $$ = nil; }
-| basic                                         { $$ = maketree1(Tbasic, $1); }
+| basic                                         { $$ = basictree($1); }
 | block epilog                                  { $$ = hangepilog($1, $2); }
 | cmd Tpipe nl cmd                              { $$ = hangchild2($2, $1, 0, $4, 1); }
 | cmd Tandand nl cmd                            { $$ = maketree2(Tandand, $1, $4); }
diff --git a/src/cmd/rc/sys.c b/src/cmd/rc/sys.c
index a845122..9b6124b 100644
--- a/src/cmd/rc/sys.c
+++ b/src/cmd/rc/sys.c
@@ -3,14 +3,13 @@
 // -----------------------------------------------------------------------
 // internal
 
-static
-char**
+static char**
 mkargv(Word *args)
 {
     char **argv=emalloc((count(args)+2)*sizeof(char *));
-    char **argp=argv+1;	/* leave one at front for runcoms */
+    char **argp=argv+1;	/* leave one at front for executable */
 
-    for(;args;args=args->link) 
+    for(; args; args=args->link) 
         *argp++=args->str;
     *argp=nil;
 
@@ -107,9 +106,11 @@ redirect(Redir *r)
     case Rdup:
         dup2(r->from, r->to); // TODO: error checking
         break;
+
     case Rclose:
         close(r->from);
         break;
+
     default:
         fatal("unrecognized redirection type %d\n", r->type);
     }
diff --git a/src/cmd/rc/tree.c b/src/cmd/rc/tree.c
index 3703a25..3b7aeb8 100644
--- a/src/cmd/rc/tree.c
+++ b/src/cmd/rc/tree.c
@@ -78,6 +78,25 @@ hangchild3(Tree *node, Tree *c0, Tree *c1, Tree *c2)
     return node;
 }
 
+/*
+ * add a Tbasic node.
+ * percolate all the redirections up to the root
+ */
+Tree*
+basictree(Tree *cmd)
+{
+    Tree *c;
+    cmd = maketree1(Tbasic, cmd);
+    for(c=cmd->child[0]; c->type==Targs; c = c->child[0]){
+        if(c->child[1]->type == Tdup || c->child[1]->type == Tredir){
+            c->child[1]->child[1] = cmd;
+            cmd = c->child[1];
+            c->child[1] = nil;
+        }
+    }
+    return cmd;
+}
+
 Tree*
 hangepilog(Tree *cmd, Tree *epi)
 {
diff --git a/src/cmd/rc/var.c b/src/cmd/rc/var.c
index 6004bb9..e2d3e08 100644
--- a/src/cmd/rc/var.c
+++ b/src/cmd/rc/var.c
@@ -6,7 +6,7 @@
 // -----------------------------------------------------------------------
 // globals
 
-struct Keyword 
+struct Keyword
 {
     char *name;
     int   type;
-- 
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