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|
/*
This file is part of libmicrohttpd
(C) 2013 Christian Grothoff (and other contributing authors)
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/**
* @file demo.c
* @brief complex demonstration site: upload, index, download
* @author Christian Grothoff
*/
#include "platform.h"
#include <microhttpd.h>
#include <unistd.h>
#include <pthread.h>
#include <sys/types.h>
#include <dirent.h>
/**
* Page returned for file-not-found.
*/
#define FILE_NOT_FOUND_PAGE "<html><head><title>File not found</title></head><body>File not found</body></html>"
/**
* Page returned for internal errors.
*/
#define INTERNAL_ERROR_PAGE "<html><head><title>Internal error</title></head><body>Internal error</body></html>"
/**
* Head of index page.
*/
#define INDEX_PAGE_HEADER "<html>\n<head><title>Welcome</title></head>\n<body>\n"\
"<form method=\"POST\" enctype=\"multipart/form-data\" action=\"/\">"\
"Upload: <input type=\"file\" name=\"upload\"/>"\
"<input type=\"submit\" value=\"Send\"/>"\
"</form>\n"\
"<ol>\n"
/**
* Footer of index page.
*/
#define INDEX_PAGE_FOOTER "</ol>\n</body>\n</html>"
/**
* Response returned if the requested file does not exist (or is not accessible).
*/
static struct MHD_Response *file_not_found_response;
/**
* Response returned for internal errors.
*/
static struct MHD_Response *internal_error_response;
/**
* Response returned for '/' (GET) to list the contents of the directory and allow upload.
*/
static struct MHD_Response *cached_directory_response;
/**
* Mutex used when we update the cached directory response object.
*/
static pthread_mutex_t mutex;
/**
* Replace the existing 'cached_directory_response' with the
* given response.
*
* @param response new directory response
*/
static void
update_cached_response (struct MHD_Response *response)
{
(void) pthread_mutex_lock (&mutex);
if (NULL != cached_directory_response)
MHD_destroy_response (cached_directory_response);
cached_directory_response = response;
(void) pthread_mutex_unlock (&mutex);
}
/**
* Re-scan our local directory and re-build the index.
*/
static void
update_directory ()
{
static size_t initial_allocation = 32 * 1024; /* initial size for response buffer */
DIR *dir;
struct dirent *de;
struct MHD_Response *response;
char *buf;
size_t buf_len;
size_t off;
dir = opendir (".");
if (NULL == dir)
goto err;
buf_len = initial_allocation;
buf = malloc (buf_len);
if (NULL == buf)
{
closedir (dir);
goto err;
}
off = snprintf (buf, buf_len,
"%s",
INDEX_PAGE_HEADER);
while (NULL != (de = readdir (dir)))
{
if ('.' == de->d_name[0])
continue;
if (off + 1024 > buf_len)
{
void *r;
if ( (2 * buf_len + 1024) < buf_len)
break; /* more than SIZE_T _index_ size? Too big for us */
buf_len = 2 * buf_len + 1024;
if (NULL == (r = realloc (buf, buf_len)))
break; /* out of memory */
buf = r;
}
off += snprintf (&buf[off], buf_len - off,
"<li><a href=\"/%s\">%s</a></li>\n",
de->d_name,
de->d_name);
}
/* we ensured always +1k room, filenames are ~256 bytes,
so there is always still enough space for the footer
without need for a final reallocation check. */
off += snprintf (&buf[off], buf_len - off,
"%s",
INDEX_PAGE_FOOTER);
closedir (dir);
initial_allocation = buf_len; /* remember for next time */
response = MHD_create_response_from_buffer (off,
buf,
MHD_RESPMEM_MUST_FREE);
update_cached_response (response);
return;
err:
/* failed to list directory, use error page */
update_cached_response (NULL);
}
/**
* Context we keep for an upload.
*/
struct UploadContext
{
/**
* Handle where we write the uploaded file to.
*/
int fd;
/**
* Post processor we're using to process the upload.
*/
struct MHD_PostProcessor *pp;
/**
* Handle to connection that we're processing the upload for.
*/
struct MHD_Connection *connection;
};
/**
* Iterator over key-value pairs where the value
* maybe made available in increments and/or may
* not be zero-terminated. Used for processing
* POST data.
*
* @param cls user-specified closure
* @param kind type of the value, always MHD_POSTDATA_KIND when called from MHD
* @param key 0-terminated key for the value
* @param filename name of the uploaded file, NULL if not known
* @param content_type mime-type of the data, NULL if not known
* @param transfer_encoding encoding of the data, NULL if not known
* @param data pointer to size bytes of data at the
* specified offset
* @param off offset of data in the overall value
* @param size number of bytes in data available
* @return MHD_YES to continue iterating,
* MHD_NO to abort the iteration
*/
static int
process_upload_data (void *cls,
enum MHD_ValueKind kind,
const char *key,
const char *filename,
const char *content_type,
const char *transfer_encoding,
const char *data,
uint64_t off,
size_t size)
{
struct UploadContext *uc = cls;
if (NULL == filename)
{
fprintf (stderr, "No filename, aborting upload\n");
return MHD_NO; /* no filename, error */
}
fprintf (stderr, "Got %u bytes of upload data for %s\n",
(unsigned int) size, filename);
if (-1 == uc->fd)
{
uc->fd = open (filename,
O_CREAT | O_EXCL
#if O_LARGEFILE
| O_LARGEFILE
#endif
#if O_NONBLOCK
| O_NONBLOCK
#endif
| O_WRONLY,
S_IRUSR | S_IWUSR);
if (-1 == uc->fd)
{
// FIXME: generate error page NICELY
fprintf (stderr, "Error opening file to write!\n");
return MHD_NO;
}
}
if ( (0 != size) &&
(size != write (uc->fd, data, size)) )
{
// FIXME: generate error page NICELY
fprintf (stderr, "Error writing to disk!\n");
return MHD_NO;
}
return MHD_YES;
}
/**
* Function called whenever a request was completed.
* Used to clean up 'struct UploadContext' objects.
*
* @param cls client-defined closure, NULL
* @param connection connection handle
* @param con_cls value as set by the last call to
* the MHD_AccessHandlerCallback, points to NULL if this was
* not an upload
* @param toe reason for request termination
*/
static void
response_completed_callback (void *cls,
struct MHD_Connection *connection,
void **con_cls,
enum MHD_RequestTerminationCode toe)
{
struct UploadContext *uc = *con_cls;
if (NULL == uc)
return; /* this request wasn't an upload request */
if (NULL != uc->pp)
{
MHD_destroy_post_processor (uc->pp);
uc->pp = NULL;
}
if (-1 != uc->fd)
{
close (uc->fd);
fprintf (stderr, "Possible upload failure, need to remove file?!\n");
/* FIXME: unlink here on error!? */
}
free (uc);
}
/**
* Return the current directory listing.
*
* @param connection connection to return the directory for
* @return MHD_YES on success, MHD_NO on error
*/
static int
list_directory (struct MHD_Connection *connection)
{
int ret;
(void) pthread_mutex_lock (&mutex);
if (NULL == cached_directory_response)
ret = MHD_queue_response (connection,
MHD_HTTP_INTERNAL_SERVER_ERROR,
internal_error_response);
else
ret = MHD_queue_response (connection,
MHD_HTTP_OK,
cached_directory_response);
(void) pthread_mutex_unlock (&mutex);
return ret;
}
/**
* Main callback from MHD, used to generate the page.
*
* @param cls NULL
* @param connection connection handle
* @param url requested URL
* @param method GET, PUT, POST, etc.
* @param version HTTP version
* @param upload_data data from upload (PUT/POST)
* @param upload_data_size number of bytes in "upload_data"
* @param ptr our context
* @return MHD_YES on success, MHD_NO to drop connection
*/
static int
generate_page (void *cls,
struct MHD_Connection *connection,
const char *url,
const char *method,
const char *version,
const char *upload_data,
size_t *upload_data_size, void **ptr)
{
struct MHD_Response *response;
int ret;
int fd;
struct stat buf;
if (0 != strcmp (url, "/"))
{
/* should be file download */
if (0 != strcmp (method, MHD_HTTP_METHOD_GET))
return MHD_NO; /* unexpected method (we're not polite...) */
if ( (0 == stat (&url[1], &buf)) &&
(NULL == strstr (&url[1], "..")) &&
('/' != url[1]))
fd = open (&url[1], O_RDONLY);
else
fd = -1;
if (-1 == fd)
return MHD_queue_response (connection,
MHD_HTTP_NOT_FOUND,
file_not_found_response);
if (NULL == (response = MHD_create_response_from_fd (buf.st_size,
fd)))
{
/* internal error (i.e. out of memory) */
(void) close (fd);
return MHD_NO;
}
ret = MHD_queue_response (connection,
MHD_HTTP_OK,
response);
MHD_destroy_response (response);
return ret;
}
if (0 == strcmp (method, MHD_HTTP_METHOD_POST))
{
/* upload! */
struct UploadContext *uc = *ptr;
if (NULL == uc)
{
if (NULL == (uc = malloc (sizeof (struct UploadContext))))
return MHD_NO; /* out of memory, close connection */
uc->fd = -1;
uc->connection = connection;
uc->pp = MHD_create_post_processor (connection,
32 * 1024 /* buffer size */,
&process_upload_data, uc);
if (NULL == uc->pp)
{
/* out of memory, close connection */
free (uc);
return MHD_NO;
}
*ptr = uc;
return MHD_YES;
}
if (0 != *upload_data_size)
{
ret = MHD_post_process (uc->pp,
upload_data,
*upload_data_size);
*upload_data_size = 0;
return ret;
}
/* end of upload, finish it! */
MHD_destroy_post_processor (uc->pp);
uc->pp = NULL;
if (-1 != uc->fd)
{
close (uc->fd);
uc->fd = -1;
}
update_directory ();
return list_directory (connection);
}
if (0 == strcmp (method, MHD_HTTP_METHOD_GET))
return list_directory (connection);
/* unexpected request, refuse */
fprintf (stderr, "Unexpected request, refusing\n");
return MHD_NO;
}
/**
* Entry point to demo. Note: this HTTP server will make all
* files in the current directory and its subdirectories available
* to anyone.
*
* @param argc number of arguments in argv
* @param argv first and only argument should be the port number
* @return 0 on success
*/
int
main (int argc, char *const *argv)
{
struct MHD_Daemon *d;
unsigned int port;
if ( (argc != 2) ||
(1 != sscanf (argv[1], "%u", &port)) ||
(UINT16_MAX < port) )
{
fprintf (stderr,
"%s PORT\n", argv[0]);
return 1;
}
(void) pthread_mutex_init (&mutex, NULL);
file_not_found_response = MHD_create_response_from_buffer (strlen (FILE_NOT_FOUND_PAGE),
(void *) FILE_NOT_FOUND_PAGE,
MHD_RESPMEM_PERSISTENT);
internal_error_response = MHD_create_response_from_buffer (strlen (INTERNAL_ERROR_PAGE),
(void *) INTERNAL_ERROR_PAGE,
MHD_RESPMEM_PERSISTENT);
update_directory ();
d = MHD_start_daemon (MHD_USE_SELECT_INTERNALLY | MHD_USE_DEBUG,
port,
NULL, NULL,
&generate_page, NULL,
MHD_OPTION_THREAD_POOL_SIZE, (unsigned int) 8,
MHD_OPTION_NOTIFY_COMPLETED, &response_completed_callback, NULL,
MHD_OPTION_END);
if (NULL == d)
return 1;
(void) getc (stdin);
MHD_stop_daemon (d);
MHD_destroy_response (file_not_found_response);
MHD_destroy_response (internal_error_response);
update_cached_response (NULL);
(void) pthread_mutex_destroy (&mutex);
return 0;
}
/* end of demo.c */
|
