From bf03074e346b004659196b6c17eee04dbffd3ac2 Mon Sep 17 00:00:00 2001
From: Nicholas Noll <nbnoll@eml.cc>
Date: Fri, 15 Oct 2021 16:18:02 -0700
Subject: feat(rc): working prototype of input->compile->print loop

---
 sys/cmd/rc/sys.c | 139 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 139 insertions(+)
 create mode 100644 sys/cmd/rc/sys.c

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

diff --git a/sys/cmd/rc/sys.c b/sys/cmd/rc/sys.c
new file mode 100644
index 0000000..2c6a19d
--- /dev/null
+++ b/sys/cmd/rc/sys.c
@@ -0,0 +1,139 @@
+#include "rc.h"
+
+struct Wait
+{
+    int len, cap, *pid;
+};
+
+static struct Wait wait;
+
+// -----------------------------------------------------------------------
+// internal
+
+static
+char**
+mkargv(Word *args)
+{
+    char **argv=emalloc((count(args)+2)*sizeof(char *));
+    char **argp=argv+1;	/* leave one at front for runcoms */
+
+    for(;args;args=args->link) 
+        *argp++=args->str;
+    *argp=nil;
+
+    return argv;
+}
+
+static
+Word*
+envval(char *s)
+{
+    Word *v;
+    char *t, c;
+
+    for(t=s; *t && *t!='\1'; t++)
+        ;
+
+    c  = *t;
+    *t = '\0';
+
+    v = makeword(s, (c=='\0') ? nil : envval(t+1));
+    *t=c;
+
+    return v;
+}
+
+// -----------------------------------------------------------------------
+// exported
+
+void
+initenv(void)
+{
+    extern char **environ;
+
+    char *s;
+    char **env;
+
+    for(env=environ; *env; env++) {
+        for(s=*env; *s && *s != '(' && *s != '='; s++)
+            ;
+        switch(*s){
+        case '\0':
+            break;
+        case '(': /* ignore functions */
+            break;
+        case '=':
+            *s = '\0';
+            setvar(*env, envval(s+1));
+            *s = '=';
+            break;
+        }
+    }
+}
+
+void
+clearwait(void)
+{
+    wait.len = 0;
+}
+
+int
+havewait(int pid)
+{
+    int i;
+
+    for(i=0; i<wait.len; i++)
+        if(wait.pid[i] == pid)
+            return 1;
+    return 0;
+}
+
+void
+addwait(int pid)
+{
+    if(wait.len == wait.cap){
+        wait.cap = wait.cap + 2;
+        wait.pid = erealloc(wait.pid, wait.cap*sizeof(*wait.pid));
+    }
+    wait.pid[wait.len++] = pid;
+}
+
+/*
+int
+waitfor(int pid)
+{
+    Thread *p;
+    struct WaitMsg *w;
+    char errbuf[ERRMAX];
+
+    if(pid >= 0 && !havewait(pid))
+        return 0;
+}
+*/
+
+void
+execute(Word *cmd, Word *path)
+{
+    int nc;
+    char **argv = mkargv(cmd);
+    char **env  = mkenv();
+    char file[1024];
+
+    for(; path; path=path->link){
+        nc = strlen(path->str);
+        if(nc < arrlen(file)){
+            strcpy(file, path->str);
+            if(*file){
+                strcat(file, "/");
+                nc++;
+            }
+            if(nc+strlen(argv[1]) < 1024){
+                strcat(file, argv[1]);
+                execve(file, argv+1, env);
+            }else
+                fatal("command name too long");
+        }
+    }
+    efree(argv);
+    fatal("failed to exec\n");
+}
-- 
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