From 973b8255aefa2f10a70e0ac8a0cda0cbd37aaa28 Mon Sep 17 00:00:00 2001
From: Max Wash <mbswash@gmail.com>
Date: Sun, 22 May 2022 21:31:04 +0100
Subject: [PATCH] Added support for integrating dynamic linker into libc

---
 photon/libc/sys/horizon/init.c                | 99 ++++++++++++++++---
 .../libc/sys/horizon/machine/x86_64/pthread.s |  6 +-
 2 files changed, 88 insertions(+), 17 deletions(-)

diff --git a/photon/libc/sys/horizon/init.c b/photon/libc/sys/horizon/init.c
index bc55766..9f2d03e 100644
--- a/photon/libc/sys/horizon/init.c
+++ b/photon/libc/sys/horizon/init.c
@@ -17,6 +17,8 @@
 #include "__heap.h"
 #include "__fio.h"
 
+#define DYLD_PARENT_IMAGE
+
 /* maximum of 32 handles can be received sent as arguments */
 #define MAX_HANDLE_ARGS 32
 
@@ -40,8 +42,13 @@ static void dbg_log(const char *format, ...)
 }
 #endif
 
+#ifdef DYLD_PARENT_IMAGE
+extern mx_vaddr_t dyld_load_exec(int argc, const char **argv);
+#endif
+
 static const char **environ = NULL;
 static char arg_msg_buf[MAX_MSG_SIZE];
+static mx_bootstrap_handle_t arg_handles[MAX_HANDLE_ARGS];
 
 const char **__crt_environ()
 {
@@ -213,7 +220,7 @@ static void init_stdio(mx_bootstrap_handle_t *handles, size_t nhandles)
     dbg_log("** photon: stdio init finished\n");
 }
 
-int __crt_init(mx_handle_t bootstrap)
+static int do_init(mx_handle_t bootstrap, bool enable_fs, bool enable_stdio, int *out_argc, const char ***out_argv)
 {
     dbg_log("reading bootstrap message from %x\n", bootstrap);
     mx_signals_t sig = 0;
@@ -228,8 +235,6 @@ int __crt_init(mx_handle_t bootstrap)
 
     mx_handle_t handles[MAX_HANDLE_ARGS + 1];
 
-    mx_bootstrap_handle_t handle_info[MAX_HANDLE_ARGS + 1];
-
     dbg_log("receiving message from handle %lx\n", bootstrap);
     mx_status_t err = mx_tunnel_read(bootstrap,
             arg_msg_buf, MAX_MSG_SIZE,
@@ -245,12 +250,15 @@ int __crt_init(mx_handle_t bootstrap)
     mx_bootstrap_msg_t *msg = (mx_bootstrap_msg_t *)arg_msg_buf;
 
     dbg_log("extracting handles\n");
-    extract_arg_handles(msg, handles, nr_handles, handle_info);
-    handle_info[nr_handles].handle = bootstrap;
-    handle_info[nr_handles].info = MX_B_HND(MX_B_TUNNEL_BTSTP, 0);
+    extract_arg_handles(msg, handles, nr_handles, arg_handles);
+#if 0
+    arg_handles[nr_handles].handle = bootstrap;
+    arg_handles[nr_handles].info = MX_B_HND(MX_B_TUNNEL_BTSTP, 0);
     nr_handles++;
+#endif
 
-    mx_bootstrap_handle_init(handle_info, nr_handles);
+    dbg_log("extracted %zu handles\n", nr_handles);
+    mx_bootstrap_handle_init(arg_handles, nr_handles);
 
     const char **argv = NULL, **envp = NULL, **namep = NULL;
 
@@ -264,14 +272,25 @@ int __crt_init(mx_handle_t bootstrap)
 
     parse_args(msg, argv, envp, namep);
 
-    init_stdio(handle_info, nr_handles);
+    *out_argc = msg->args_num;
+    *out_argv = argv;
+
+    if (enable_stdio) {
+        init_stdio(arg_handles, nr_handles);
+    } else {
+        __fio_init(-1, -1, -1);
+    }
+
+    if (!enable_fs) {
+        return 0;
+    }
 
     mio_namespace *ns = mio_namespace_create();
 
     if (msg->names_num > 0) {
         for (size_t i = 0; i < nr_handles; i++) {
-            int type = MX_B_HND_TYPE(handle_info[i].info);
-            int arg = MX_B_HND_ARG(handle_info[i].info);
+            int type = MX_B_HND_TYPE(arg_handles[i].info);
+            int arg = MX_B_HND_ARG(arg_handles[i].info);
 
             if (type != MX_B_NS_DIR && type != MX_B_TUNNEL_CWD) {
                 continue;
@@ -280,17 +299,69 @@ int __crt_init(mx_handle_t bootstrap)
             const char *path = namep[arg];
 
             if (type == MX_B_TUNNEL_CWD) {
-                mio_set_cwd(handle_info[i].handle, path);
+                mio_set_cwd(arg_handles[i].handle, path);
             } else {
-                mio_namespace_add_entry(ns, path, handle_info[i].handle);
+                mio_namespace_add_entry(ns, path, arg_handles[i].handle);
             }
         }
     }
 
     mio_set_global_namespace(ns);
+    return 0;
+}
 
-    dbg_log("calling main\n");
-    int ret = main(msg->args_num, argv);
+static int do_run(mx_handle_t bootstrap)
+{
+    int argc;
+    const char **argv;
+
+    int err = do_init(bootstrap, true, true, &argc, &argv);
+    if (err != 0) {
+        return err;
+    }
+
+    return main(argc, argv);
+}
+
+#ifdef DYLD_PARENT_IMAGE
+static int do_load_and_run(mx_handle_t bootstrap)
+{
+    int argc;
+    const char **argv;
+
+    int err = do_init(bootstrap, false, false, &argc, &argv);
+    if (err != 0) {
+        return err;
+    }
+
+    mx_vaddr_t main_ptr = dyld_load_exec(argc, argv);
+    if (!main_ptr) {
+        return -1;
+    }
+
+    mx_bootstrap_handle_cleanup();
+
+    err = do_init(bootstrap, true, true, &argc, &argv);
+    if (err != 0) {
+        return err;
+    }
+
+    int(*main_func)(int, const char **) = (int(*)(int, const char **))main_ptr;
+    if (!main_func) {
+        return -1;
+    }
+
+    return main_func(argc, argv);
+}
+#endif
+
+int __crt_init(mx_handle_t bootstrap, mx_vaddr_t arg2)
+{
+#ifndef DYLD_PARENT_IMAGE
+    int ret = do_run(bootstrap);
+#else
+    int ret = do_load_and_run(bootstrap);
+#endif
 
     fflush(stdout);
     fflush(stderr);
diff --git a/photon/libc/sys/horizon/machine/x86_64/pthread.s b/photon/libc/sys/horizon/machine/x86_64/pthread.s
index 5dfb86f..a0c6148 100644
--- a/photon/libc/sys/horizon/machine/x86_64/pthread.s
+++ b/photon/libc/sys/horizon/machine/x86_64/pthread.s
@@ -1,7 +1,7 @@
-.global pthread_self
-.type pthread_self, @function
+.global __pthread_self
+.type __pthread_self, @function
 
-pthread_self:
+__pthread_self:
     push %rbp
     mov %rsp, %rbp