1 files changed, 137 insertions, 0 deletions
diff --git a/src/cmd/rc/sys.c b/src/cmd/rc/sys.c
new file mode 100644
index 0000000..807359d
--- /dev/null
+++ b/src/cmd/rc/sys.c
@@ -0,0 +1,137 @@
+#include "rc.h"
+
+// -----------------------------------------------------------------------
+// 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
+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[0]){
+                strcat(file, "/");
+                nc++;
+            }
+            if(nc+strlen(argv[1]) < arrlen(file)){
+                strcat(file, argv[1]);
+                execve(file, argv+1, env);
+            }else
+                fatal("command name too long");
+        }
+    }
+    print(shell.err, "could not execute command: %s\n", argv[1]);
+    efree(argv);
+}
+
+void
+redirect(Redir *r)
+{
+    if(r){
+        redirect(r->link);
+        switch(r->type){
+        case Ropen:
+            if(r->from != r->to){
+                dup2(r->from, r->to);
+                close(r->from);
+            }
+            break;
+        case Rdupfd:
+            dup2(r->from, r->to); // TODO: error checking
+            break;
+        case Rclose:
+            close(r->from);
+            break;
+        default:
+            fatal("unrecognized redirection type %d\n", r->type);
+        }
+    }
+}
+
+int
+mapfd(int fd)
+{
+    Redir *r;
+    for(r = runner->redir.end; r; r = r->link){
+        switch(r->type){
+        case Rclose:
+            if(r->from == fd)
+                fd = -1;
+            break;
+        case Rdupfd:
+        case Ropen:
+            if(r->to == fd)
+                fd = r->from;
+            break;
+        }
+    }
+
+    return fd;
+}