/**
* Launch simple commands (commands without file I/O) and return response
*
* @param url Target URL
* @param method HTTP method (GET/PUT/POST)
* @param followloc Whether or not need to set CURLOPT_FOLLOWLOCATION
* @param response Response from remote service
* @return 0 for success and non-zero value to indicate error
*/
static int launchCmd(const char *url, enum HttpHeader method,
enum Redirect followloc, struct Response **response)
{
CURL *curl = NULL;
CURLcode curlCode;
int ret = 0;
struct Response *resp = NULL;
resp = calloc(1, sizeof(struct Response));
if (!resp) {
return ENOMEM;
}
ret = initResponseBuffer(&(resp->body));
if (ret) {
goto done;
}
ret = initResponseBuffer(&(resp->header));
if (ret) {
goto done;
}
initCurlGlobal();
curl = curl_easy_init();
if (!curl) {
ret = ENOMEM; // curl_easy_init does not return error code,
// and most of its errors are caused by malloc()
fprintf(stderr, "ERROR in curl_easy_init.\n");
goto done;
}
/* Set callback function for reading data from remote service */
curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, writefunc);
curl_easy_setopt(curl, CURLOPT_WRITEDATA, resp->body);
curl_easy_setopt(curl, CURLOPT_HEADERFUNCTION, writefunc);
curl_easy_setopt(curl, CURLOPT_WRITEHEADER, resp->header);
curl_easy_setopt(curl, CURLOPT_URL, url);
switch(method) {
case GET:
break;
case PUT:
curl_easy_setopt(curl, CURLOPT_CUSTOMREQUEST, "PUT");
break;
case POST:
curl_easy_setopt(curl, CURLOPT_CUSTOMREQUEST, "POST");
break;
case DELETE:
curl_easy_setopt(curl, CURLOPT_CUSTOMREQUEST, "DELETE");
break;
default:
ret = EINVAL;
fprintf(stderr, "ERROR: Invalid HTTP method\n");
goto done;
}
if (followloc == YES) {
curl_easy_setopt(curl, CURLOPT_FOLLOWLOCATION, 1);
}
/* Now run the curl handler */
curlCode = curl_easy_perform(curl);
if (curlCode != CURLE_OK) {
ret = EIO;
fprintf(stderr, "ERROR: preform the URL %s failed, <%d>: %s\n",
url, curlCode, curl_easy_strerror(curlCode));
}
done:
if (curl != NULL) {
curl_easy_cleanup(curl);
}
if (ret) {
free(resp);
resp = NULL;
}
*response = resp;
return ret;
}
/**
* The function does the write operation by connecting to a DataNode.
* The function keeps the connection with the DataNode until
* the closeFlag is set. Whenever the current data has been sent out,
* the function blocks waiting for further input from user or close.
*
* @param url URL of the remote DataNode
* @param method PUT for create and POST for append
* @param uploadBuffer Buffer storing user's data to write
* @param response Response from remote service
* @return 0 for success and non-zero value to indicate error
*/
static int launchWrite(const char *url, enum HttpHeader method,
struct webhdfsBuffer *uploadBuffer,
struct Response **response)
{
CURLcode curlCode;
struct Response* resp = NULL;
struct curl_slist *chunk = NULL;
CURL *curl = NULL;
int ret = 0;
if (!uploadBuffer) {
fprintf(stderr, "ERROR: upload buffer is NULL!\n");
return EINVAL;
}
initCurlGlobal();
resp = calloc(1, sizeof(struct Response));
if (!resp) {
return ENOMEM;
}
ret = initResponseBuffer(&(resp->body));
if (ret) {
goto done;
}
ret = initResponseBuffer(&(resp->header));
if (ret) {
goto done;
}
// Connect to the datanode in order to create the lease in the namenode
curl = curl_easy_init();
if (!curl) {
fprintf(stderr, "ERROR: failed to initialize the curl handle.\n");
return ENOMEM;
}
curl_easy_setopt(curl, CURLOPT_URL, url);
curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, writefunc);
curl_easy_setopt(curl, CURLOPT_WRITEDATA, resp->body);
curl_easy_setopt(curl, CURLOPT_HEADERFUNCTION, writefunc);
curl_easy_setopt(curl, CURLOPT_WRITEHEADER, resp->header);
curl_easy_setopt(curl, CURLOPT_READFUNCTION, readfunc);
curl_easy_setopt(curl, CURLOPT_READDATA, uploadBuffer);
curl_easy_setopt(curl, CURLOPT_UPLOAD, 1L);
chunk = curl_slist_append(chunk, "Transfer-Encoding: chunked");
curl_easy_setopt(curl, CURLOPT_HTTPHEADER, chunk);
chunk = curl_slist_append(chunk, "Expect:");
curl_easy_setopt(curl, CURLOPT_HTTPHEADER, chunk);
switch(method) {
case PUT:
curl_easy_setopt(curl, CURLOPT_CUSTOMREQUEST, "PUT");
break;
case POST:
curl_easy_setopt(curl, CURLOPT_CUSTOMREQUEST, "POST");
break;
default:
ret = EINVAL;
fprintf(stderr, "ERROR: Invalid HTTP method\n");
goto done;
}
curlCode = curl_easy_perform(curl);
if (curlCode != CURLE_OK) {
ret = EIO;
fprintf(stderr, "ERROR: preform the URL %s failed, <%d>: %s\n",
url, curlCode, curl_easy_strerror(curlCode));
}
done:
if (chunk != NULL) {
curl_slist_free_all(chunk);
}
if (curl != NULL) {
curl_easy_cleanup(curl);
}
if (ret) {
free(resp);
resp = NULL;
}
*response = resp;
return ret;
}
static int hdfsReadImpl(hdfsFS fs, hdfsFile file, void* buffer, tSize off,
tSize length, tSize *numRead)
{
int ret = 0;
char *url = NULL;
struct Response *resp = NULL;
if (fs == NULL || file == NULL || file->type != INPUT || buffer == NULL ||
length < 0) {
ret = EINVAL;
goto done;
}
if (length == 0) {
// Special case: the user supplied a buffer of zero length, so there is
// nothing to do.
*numRead = 0;
goto done;
}
resp = calloc(1, sizeof(*resp)); // resp is actually a pointer type
if (!resp) {
ret = ENOMEM;
goto done;
}
ret = initResponseBuffer(&(resp->header));
if (ret) {
goto done;
}
ret = initResponseBuffer(&(resp->body));
if (ret) {
goto done;
}
memset(buffer, 0, length);
resp->body->content = buffer;
resp->body->remaining = length;
ret = createUrlForOPEN(fs->nn, fs->port, file->file->absPath,
fs->userName, off, length, &url);
if (ret) {
goto done;
}
ret = launchOPEN(url, resp);
if (ret) {
goto done;
}
ret = parseOPEN(resp->header->content, resp->body->content);
if (ret == -1) {
// Special case: if parseOPEN returns -1, we asked for a byte range
// with outside what the file contains. In this case, hdfsRead and
// hdfsPread return 0, meaning end-of-file.
*numRead = 0;
} else if (ret == 0) {
*numRead = (tSize) resp->body->offset;
}
done:
if (resp) {
freeResponseBuffer(resp->header);
free(resp->body);
}
free(resp);
free(url);
return ret;
}
