chore: organize code

add -Wextra by default
pipefd to communicate better with parent and forked process
rustify some stuff
add the desktop parser to the file read

include/sessions.h

@@ -2,6 +2,7 @@
 #define SESSIONSH_
 
 #include <sys/types.h>
+#include <unistd.h>
 
 #include "macros.h"
 #include "util.h"
@@ -12,10 +13,58 @@ enum SessionType {
   SHELL,
 };
 
+enum ExecType {
+  EXEC_SHELL,
+  EXEC_DESKTOP,
+};
+
+struct desktop_exec {
+  char** args;
+  int arg_count;
+};
+
+struct session_exec {
+  enum ExecType typ;
+  union {
+    char* shell;
+    struct desktop_exec desktop;
+  };
+};
+
+static inline struct session_exec session_exec_shell(char* shell) {
+  return (struct session_exec){
+      .typ = EXEC_SHELL,
+      .shell = shell,
+  };
+}
+
+static inline struct session_exec session_exec_desktop(int arg_count,
+                                                       char** args) {
+  return (struct session_exec){
+      .typ = EXEC_DESKTOP,
+      .desktop =
+          {
+              .args = args,
+              .arg_count = arg_count,
+          },
+  };
+}
+
+static inline int session_exec_exec(struct session_exec* exec,
+                                    char** NNULLABLE envlist) {
+  switch (exec->typ) {
+    case EXEC_SHELL:
+      return execle(exec->shell, exec->shell, NULL, envlist);
+    case EXEC_DESKTOP:
+      return execve(exec->desktop.args[0], exec->desktop.args, envlist);
+    default:
+      __builtin_unreachable();
+  }
+}
+
 struct session {
   char* NNULLABLE name;
-  char* NNULLABLE exec;
-  char* NULLABLE tryexec;
+  struct session_exec exec;
   enum SessionType type;
 };