From 6d50d5b97d49a74a8faf587ec2bbf234626adf0c Mon Sep 17 00:00:00 2001
From: Nicholas Noll <nbnoll@eml.cc>
Date: Tue, 19 Oct 2021 14:16:54 -0700
Subject: Feat(rc): added subshell commands and cd builtin

Slowly chipping away at a decent feature list.
Subshell commands are executed by @{ ... }.
---
 sys/cmd/rc/exec.c | 86 ++++++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 85 insertions(+), 1 deletion(-)

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

diff --git a/sys/cmd/rc/exec.c b/sys/cmd/rc/exec.c
index 37c289b..217f7ee 100644
--- a/sys/cmd/rc/exec.c
+++ b/sys/cmd/rc/exec.c
@@ -17,6 +17,7 @@ static Word nullpath = { .str="", .link=nil };
 
 struct Builtin builtin[]={
     {".",     xdot},
+    {"cd",    xcd},
     {"fg",    xfg},
     {"jobs",  xjob},
     0,
@@ -326,7 +327,7 @@ xdot(void)
     Thread *old;
     char file[512];
 
-    popword();
+    popword(); // "."
 #if 0
     if(proc->args->word && strcmp(proc->args->word->str, "-i")==0){
         iflag = 1;
@@ -382,6 +383,49 @@ xdot(void)
     //ndot++;
 }
 
+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();
+}
+
 void
 xjob(void)
 {
@@ -680,6 +724,37 @@ Xasync(void)
     }
 }
 
+void
+Xsubshell(void)
+{
+    int pid;
+
+    switch(pid=fork()){
+    case -1:
+        Xerror("fork failed: try again");
+        break;
+
+    case 0: // child
+        clearwait(runner);
+        if(shell.interactive){ // NOTE: this needs to read off its caller's interactivity
+            setpid(getpid());
+            tcsetpgrp(0, runner->pgid);
+            defaultsignal();
+        }
+        run(runner->code.exe, runner->code.i+1, runner->local, 1);
+        runner->link = nil;
+        break;
+
+    default: // parent
+        setpid(pid);
+        addwait(runner, pid);
+        waitfor(runner, pid); // wait until child finishes
+        runner->code.i = runner->code.exe[runner->code.i].i; // jump to end of subshell command and continue execution
+    }
+}
+
+
+
 void
 Xbasic(void)
 {
@@ -780,6 +855,15 @@ Xflat(void)
     efree(str);
 }
 
+void
+Xbang(void)
+{
+    if(runner->status)
+        runner->status = 0;
+    else
+        runner->status = 1;
+}
+
 void
 Xexit(void)
 {
-- 
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