gistfile1.cpp

#include <curl/curl.h>
#include <stdio.h>
#include <string.h>
#include <string>

#ifndef CURLINFO_RESPONSE_CODE
	#define CURLINFO_RESPONSE_CODE CURLINFO_HTTP_CODE
#endif

std::string responseData;

static size_t
curlDataReceived(void *buffer, size_t size, size_t nmemb, void *userData) {
	responseData.append((const char *) buffer, size * nmemb);
	return size * nmemb;
}

int
main(int argc, char *argv[]) {
	if (argc > 1 && strcmp(argv[1], "--test-fix") == 0) {
		printf("Initializing libcurl\n");
		curl_global_init(CURL_GLOBAL_ALL);
	}

	CURL *curl = curl_easy_init();
	char lastErrorMessage[CURL_ERROR_SIZE];

	curl_easy_setopt(curl, CURLOPT_URL, "http://169.254.169.254/latest/meta-data/instance-type");
	curl_easy_setopt(curl, CURLOPT_NOSIGNAL, 1);
	curl_easy_setopt(curl, CURLOPT_TIMEOUT, 15);
	curl_easy_setopt(curl, CURLOPT_ERRORBUFFER, lastErrorMessage);
	curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, curlDataReceived);
	CURLcode code = curl_easy_perform(curl);
	curl_easy_cleanup(curl);

	if (code == 0) {
		long responseCode;

		if (curl_easy_getinfo(curl, CURLINFO_RESPONSE_CODE, &responseCode) != CURLE_OK) {
			printf("Cannot not autodetect Amazon instance type (internal error: could "
				"not query libcurl response code). Assuming this is not an Amazon instance\n");
			return false;
		}

		if (responseCode != 200) {
			printf("Cannot not autodetect Amazon instance type (HTTP error: response "
				"code %ld; body \"%s\"). Assuming this is not an Amazon instance\n",
				responseCode, responseData.c_str());
			return false;
		}

		if (responseData.empty()) {
			printf("Cannot not autodetect Amazon instance type (HTTP error: the server "
				"returned an empty response). Assuming this is not an Amazon instance\n");
			return false;
		}

		printf("Autodetected Amazon instance type: %s\n", responseData.c_str());
		return true;
	} else {
		printf("Cannot contact Amazon metadata server\n");
		return false;
	}

	return 0;
}