From ead340a66039096c7b4bf12dcd65e189769c6653 Mon Sep 17 00:00:00 2001
From: Nicholas Noll <nbnoll@eml.cc>
Date: Mon, 18 Oct 2021 17:51:11 -0700
Subject: feat(rc): job control prototype working for basic commands

---
 sys/cmd/rc/main.c | 74 +++++++++++++++++++++++++++++++++++--------------------
 1 file changed, 47 insertions(+), 27 deletions(-)

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

diff --git a/sys/cmd/rc/main.c b/sys/cmd/rc/main.c
index 46a4e0f..d1bbd06 100644
--- a/sys/cmd/rc/main.c
+++ b/sys/cmd/rc/main.c
@@ -2,9 +2,53 @@
 #include "parse.h"
 #include "exec.h"
 
-int     rcpid;
+#include <signal.h>
+#include <termios.h>
+
+// -----------------------------------------------------------------------
+// globals
+
 Io     *errio = nil;
-Thread *shell = nil;
+Thread *proc  = nil;
+Shell shell   = { 0 };
+
+// -----------------------------------------------------------------------
+// functions
+
+void
+initshell(void)
+{
+    if((shell.interactive=isatty(0))){
+        while(tcgetpgrp(0) != (shell.pid = getpgrp()))
+            kill(-shell.pid, SIGTTIN);
+
+        /* ignore job control signals */
+        signal(SIGINT,  SIG_IGN);
+        signal(SIGQUIT, SIG_IGN);
+        signal(SIGTSTP, SIG_IGN);
+        signal(SIGTTIN, SIG_IGN);
+        signal(SIGTTOU, SIG_IGN);
+        /* 
+         * NOTE: if SIGCHLD is set to SIG_IGN then
+         *  1. children that terminate do not become zombies
+         *  2. call a to wait() will block until all children have terminated
+         *  3. the call to wait will fail with errno == ECHILD
+         *  see for discussion:
+         *      https://stackoverflow.com/questions/1608017/no-child-process-error-from-waitpid-when-waiting-for-process-group 
+         */
+        // signal(SIGCHLD, SIG_IGN);
+
+        /* take control */
+        shell.pid = getpid();
+        if(setpgid(shell.pid, shell.pid)<0)
+            fatal("could not put shell in its own process group");
+
+        tcsetpgrp(0, shell.pid);
+    }
+}
+
+// -----------------------------------------------------------------------
+// main point of entry
 
 int
 main(int argc, char *argv[])
@@ -17,31 +61,7 @@ main(int argc, char *argv[])
 
     initenv();
     initpath();
-
-    itoa(num, rcpid = getpid());
-    setvar("pid", makeword(num, nil));
+    initshell();
 
     xboot(argc, argv);
-#if 0
-    Thread root = {
-        .cmd  = {
-            .path = "<nil>",
-            .io   = openfd(0),
-        },
-        .line = 0,
-        .flag = {
-            .i    = 1,
-            .eof  = 0,
-        },
-    };
-
-    shell = &root;
-    errio = openfd(2);
-#if 1
-    while(!yyparse())
-        ;
-#else
-    printkeycode()
-#endif
-#endif
 }
-- 
cgit v1.2.1