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/*
* Copyright 2019 The Emscripten Authors. All rights reserved.
* Emscripten is available under two separate licenses, the MIT license and the
* University of Illinois/NCSA Open Source License. Both these licenses can be
* found in the LICENSE file.
*/
#include <alloca.h>
#include <wasi/api.h>
#include <sysexits.h>
// Much of this code comes from:
// https://github.com/CraneStation/wasi-libc/blob/master/libc-bottom-half/crt/crt1.c
// Converted malloc() calls to alloca() to avoid including malloc in all programs.
int __main_argc_argv(int argc, char *argv[]);
// If the application's `main` does not uses argc/argv, then it will be defined
// (by llvm) with an __main_void alias, and therefore this function will not
// be included, and `_start` will call the application's `__main_void` directly.
//
// If the application's `main` does use argc/argv, then _start will call this
// function which which loads argv values and sends them to to the
// application's `main` which gets mangled to `__main_argc_argv` by llvm.
__attribute__((weak))
int __main_void(void) {
/* Fill in the arguments from WASI syscalls. */
size_t argc;
char **argv = NULL;
size_t argv_buf_size;
__wasi_errno_t err;
/* Get the sizes of the arrays we'll have to create to copy in the args. */
err = __wasi_args_sizes_get(&argc, &argv_buf_size);
if (err != __WASI_ERRNO_SUCCESS) {
__wasi_proc_exit(EX_OSERR);
}
if (argc) {
/* Allocate memory for the array of pointers, adding null terminator. */
argv = alloca(sizeof(char *) * (argc + 1));
/* Allocate memory for storing the argument chars. */
uint8_t *argv_buf = alloca(sizeof(char) * argv_buf_size);
/* Make sure the last pointer in the array is NULL. */
argv[argc] = NULL;
/* Fill the argument chars, and the argv array with pointers into those chars. */
err = __wasi_args_get((uint8_t**)argv, argv_buf);
if (err != __WASI_ERRNO_SUCCESS) {
__wasi_proc_exit(EX_OSERR);
}
}
return __main_argc_argv(argc, argv);
}
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