Getting ESP32 wifi creds

// put wifi.txt on SD or alternatively on SPIFFS
// first line is SSID, next line is password
#define SPI_PORT SPI3_HOST
#define SPI_CLK 18
#define SPI_MISO 19
#define SPI_MOSI 23

#define SD_PORT SPI3_HOST
#define SD_CS 4

#include <sys/stat.h>
#include <sys/unistd.h>
#include "driver/gpio.h"
#include "driver/spi_master.h"
#include "esp_spiffs.h"
#include "esp_vfs_fat.h"
#include "esp_wifi.h"
#include "nvs_flash.h"

static char wifi_ssid[65];
static char wifi_pass[129];

static bool wifi_load(const char* path, char* ssid, char* pass) {
    FILE* file = fopen(path, "r");
    if (file != NULL) {
        // parse the file
        fgets(ssid, 64, file);
        char* sv = strchr(ssid, '\n');
        if (sv != NULL) *sv = '\0';
        sv = strchr(ssid, '\r');
        if (sv != NULL) *sv = '\0';
        fgets(pass, 128, file);
        fclose(file);
        sv = strchr(pass, '\n');
        if (sv != NULL) *sv = '\0';
        sv = strchr(pass, '\r');
        if (sv != NULL) *sv = '\0';
        return true;
    }
    return false;
}
#ifdef SPI_PORT
static void spi_init() {
    spi_bus_config_t buscfg;
    memset(&buscfg, 0, sizeof(buscfg));
    buscfg.sclk_io_num = SPI_CLK;
    buscfg.mosi_io_num = SPI_MOSI;
    buscfg.miso_io_num = SPI_MISO;
    buscfg.quadwp_io_num = -1;
    buscfg.quadhd_io_num = -1;

    buscfg.max_transfer_sz = 512 + 8;

    // Initialize the SPI bus on VSPI (SPI3)
    spi_bus_initialize(SPI_PORT, &buscfg, SPI_DMA_CH_AUTO);
}

#ifdef SD_CS
static sdmmc_card_t* sd_card = NULL;
static bool sd_init() {
    static const char mount_point[] = "/sdcard";
    esp_vfs_fat_sdmmc_mount_config_t mount_config;
    memset(&mount_config, 0, sizeof(mount_config));
    mount_config.format_if_mount_failed = false;
    mount_config.max_files = 5;
    mount_config.allocation_unit_size = 0;

    sdmmc_host_t host = SDSPI_HOST_DEFAULT();
    host.slot = SD_PORT;
    // // This initializes the slot without card detect (CD) and write
    // protect (WP)
    // // signals.
    sdspi_device_config_t slot_config;
    memset(&slot_config, 0, sizeof(slot_config));
    slot_config.host_id = (spi_host_device_t)SD_PORT;
    slot_config.gpio_cs = (gpio_num_t)SD_CS;
    slot_config.gpio_cd = SDSPI_SLOT_NO_CD;
    slot_config.gpio_wp = SDSPI_SLOT_NO_WP;
    slot_config.gpio_int = GPIO_NUM_NC;
    if (ESP_OK != esp_vfs_fat_sdspi_mount(mount_point, &host, &slot_config,
                                          &mount_config, &sd_card)) {
        return false;
    }
    return true;
}
#endif
#endif

static void spiffs_init() {
    esp_vfs_spiffs_conf_t conf;
    memset(&conf, 0, sizeof(conf));
    conf.base_path = "/spiffs";
    conf.partition_label = NULL;
    conf.max_files = 5;
    conf.format_if_mount_failed = true;
    if (ESP_OK != esp_vfs_spiffs_register(&conf)) {
        puts("Unable to initialize SPIFFS");
        while (1) vTaskDelay(5);
    }
}
// example
static void loop();
static void loop_task(void* arg) {
    uint32_t ts = pdTICKS_TO_MS(xTaskGetTickCount());
    while (1) {
        loop();
        uint32_t ms = pdTICKS_TO_MS(xTaskGetTickCount());
        if (ms > ts + 200) {
            ms = pdTICKS_TO_MS(xTaskGetTickCount());
            vTaskDelay(5);
        }
    }
}
#ifdef __cplusplus
extern "C"
#endif
void app_main() {
    printf("ESP-IDF version: %d.%d.%d\n", ESP_IDF_VERSION_MAJOR,
           ESP_IDF_VERSION_MINOR, ESP_IDF_VERSION_PATCH);
#ifdef SPI_PORT
    spi_init();  // used by the SD reader
#endif
    bool loaded = false;
    wifi_ssid[0] = 0;
    wifi_pass[0] = 0;
#ifdef SPI_PORT
#ifdef SD_CS
    if (sd_init()) {
        puts("SD card found, looking for wifi.txt creds");
        loaded = wifi_load("/sdcard/wifi.txt", wifi_ssid, wifi_pass);
    }
#endif
#endif
    if (!loaded) {
        spiffs_init();
        puts("Looking for wifi.txt creds on internal flash");
        loaded = wifi_load("/spiffs/wifi.txt", wifi_ssid, wifi_pass);
    }
    if (loaded) {
        printf("Initializing WiFi connection to %s\n", wifi_ssid);
        wifi_init(wifi_ssid, wifi_pass);
    }

    TaskHandle_t loop_handle;
    xTaskCreate(loop_task, "loop_task", 4096, NULL, 10, &loop_handle);
    printf("Free SRAM: %0.2fKB\n", esp_get_free_internal_heap_size() / 1024.f);
}
static void loop() {
    // do work
}