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/exec.c | 112 ++++++++++++++++++++++++++++++++++++++++++++----------
 1 file changed, 92 insertions(+), 20 deletions(-)

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

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)
 {
-- 
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