feat: wrapper function for bootstraping user program

[lunaix-os.git] / lunaix-os / kernel / loader / exec.c

diff --git a/lunaix-os/kernel/loader/exec.c b/lunaix-os/kernel/loader/exec.c
index 3c40f6cd227b21e77e52c4c523b7f8de8fd72c8b..1c206d2566c3d99f31ab63ecbfc793b5d403f47a 100644 (file)
--- a/lunaix-os/kernel/loader/exec.c
+++ b/lunaix-os/kernel/loader/exec.c
@@ -13,6 +13,11 @@
 size_t
 exec_str_size(const char** str_arr, size_t* length)
 {
+    if (!str_arr) {
+        *length = 0;
+        return 0;
+    }
+
     const char* chr = *str_arr;
     size_t sz = 0, len = 0;
 
@@ -58,10 +63,10 @@ __exec_remap_heap(struct ld_param* param, struct proc_mm* pvms)
 }
 
 int
-exec_loadto(struct ld_param* param,
-            struct v_file* executable,
-            const char** argv,
-            const char** envp)
+exec_load(struct ld_param* param,
+          struct v_file* executable,
+          const char** argv,
+          const char** envp)
 {
     int errno = 0;
 
@@ -88,7 +93,6 @@ exec_loadto(struct ld_param* param,
                                    .mlen = MAX_VAR_PAGES * PG_SIZE };
 
     void* mapped;
-    isr_param* intr_ctx = &param->proc->intr_ctx;
 
     if ((errno = __exec_remap_heap(param, pvms))) {
         goto done;
@@ -103,8 +107,10 @@ exec_loadto(struct ld_param* param,
 
         // make some handy infos available to user space
         ptr_t arg_start = mapped + sizeof(struct usr_exec_param);
-        memcpy(arg_start, (void*)argv, sz_argv);
-        memcpy(arg_start + sz_argv, (void*)envp, sz_envp);
+        if (argv)
+            memcpy(arg_start, (void*)argv, sz_argv);
+        if (envp)
+            memcpy(arg_start + sz_argv, (void*)envp, sz_envp);
 
         struct usr_exec_param* param = mapped;
         *param = (struct usr_exec_param){ .argc = argv_len,
@@ -114,28 +120,22 @@ exec_loadto(struct ld_param* param,
                                           .info = param->info };
         ptr_t* ustack = (ptr_t*)USTACK_TOP;
         ustack[-1] = (ptr_t)mapped;
-        intr_ctx->esp = &ustack[-1];
+        param->info.stack_top = &ustack[-1];
     } else {
         // TODO need to find a way to inject argv and envp remotely
         fail("not implemented");
     }
 
-    intr_ctx->eip = param->info.ehdr_out.e_entry;
-    // we will jump to new entry point (_u_start) upon syscall's
-    // return so execve 'will not return' from the perspective of it's invoker
-
+    param->info.entry = param->info.ehdr_out.e_entry;
 done:
     return errno;
 }
 
-__DEFINE_LXSYSCALL3(int,
-                    execve,
-                    const char*,
-                    filename,
-                    const char*,
-                    argv[],
-                    const char*,
-                    envp[])
+int
+exec_load_byname(struct ld_param* param,
+                 const char* filename,
+                 const char** argv,
+                 const char** envp)
 {
     int errno = 0;
     struct v_dnode* dnode;
@@ -149,12 +149,28 @@ __DEFINE_LXSYSCALL3(int,
         goto done;
     }
 
+    if ((errno = exec_load(param, file, argv, envp))) {
+        vfs_pclose(file, __current->pid);
+    }
+
+done:
+    return errno;
+}
+
+__DEFINE_LXSYSCALL3(int,
+                    execve,
+                    const char*,
+                    filename,
+                    const char*,
+                    argv[],
+                    const char*,
+                    envp[])
+{
+    int errno = 0;
     struct ld_param ldparam;
     ld_create_param(&ldparam, __current, VMS_SELF);
 
-    if ((errno = exec_loadto(&ldparam, file, argv, envp))) {
-        vfs_pclose(file, __current->pid);
-
+    if ((errno = exec_load_byname(&ldparam, filename, argv, envp))) {
         if ((ldparam.status & LD_STAT_FKUP)) {
             // we fucked up our address space.
             terminate_proc(11451);
@@ -163,6 +179,13 @@ __DEFINE_LXSYSCALL3(int,
         }
     }
 
+    isr_param* intr_ctx = &__current->intr_ctx;
+    intr_ctx->esp = ldparam.info.stack_top;
+    intr_ctx->eip = ldparam.info.entry;
+
+    // we will jump to new entry point (_u_start) upon syscall's
+    // return so execve 'will not return' from the perspective of it's invoker
+
 done:
     return errno;
 }
\ No newline at end of file