This esp32 component is able to load and relocate elf module.
See moduleexample and payloadexamples folders for some examples.
The code must be compiled with -fno-common option and linked with -Wl,-r -nostartfiles -nodefaultlibs -nostdlib options
Example:
#include "loader.h"
char* data = ... Elf module ...
static const ELFLoaderSymbol_t exports[] = {
{ "puts", (void*) puts },
{ "memcpy", (void*) memcpy },
{ "memmove", (void*) memmove },
{ "strcmp", (void*) strcmp },
{ "strtol", (void*) strtol },
...
};
static const ELFLoaderEnv_t env = { exports, sizeof(exports) / sizeof(*exports) };
ELFLoaderContext_t* ctx = elfLoaderInitLoadAndRelocate(data, &env);
if (!ctx) {
ESP_LOGI(TAG, "elfLoaderInitLoadAndRelocate error");
return -1;
}
if (elfLoaderSetFunc(ctx, "local_main") != 0) {
ESP_LOGI(TAG, "elfLoaderSetFunc error: local_main function not fount");
elfLoaderFree(ctx);
return -1;
}
ESP_LOGI(TAG, "Running local_main(0x10) function as int local_main(int arg)");
int r = elfLoaderRun(ctx, 0x10);
ESP_LOGI(TAG, "Result: %i", r);
elfLoaderFree(ctx);
return 0;or
$ make && make flash && make monitor
esp32> run 4
Running: test_printf_longcall_elf(0x10)
Hello world!
Result: 0x0