Illegal request

/* This file is part of libmicrohttpd Copyright (C) 2011 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 post_example.c * @brief example for processing POST requests using libmicrohttpd * @author Christian Grothoff */ #include #include #include #include #include #include /** * Invalid method page. */ #define METHOD_ERROR "Illegal requestGo away." /** * Invalid URL page. */ #define NOT_FOUND_ERROR "Not foundGo away." /** * Front page. (/) */ #define MAIN_PAGE "Welcome

What is your name? " /** * Second page. (/2) */ #define SECOND_PAGE "Tell me moreprevious %s, what is your job? " /** * Second page (/S) */ #define SUBMIT_PAGE "Ready to submit?previous " /** * Last page. */ #define LAST_PAGE "Thank youThank you." /** * Name of our cookie. */ #define COOKIE_NAME "session" /** * State we keep for each user/session/browser. */ struct Session { /** * We keep all sessions in a linked list. */ struct Session *next; /** * Unique ID for this session. */ char sid[33]; /** * Reference counter giving the number of connections * currently using this session. */ unsigned int rc; /** * Time when this session was last active. */ time_t start; /** * String submitted via form. */ char value_1[64]; /** * Another value submitted via form. */ char value_2[64]; }; /** * Data kept per request. */ struct Request { /** * Associated session. */ struct Session *session; /** * Post processor handling form data (IF this is * a POST request). */ struct MHD_PostProcessor *pp; /** * URL to serve in response to this POST (if this request * was a 'POST') */ const char *post_url; }; /** * Linked list of all active sessions. Yes, O(n) but a * hash table would be overkill for a simple example... */ static struct Session *sessions; /** * Return the session handle for this connection, or * create one if this is a new user. */ static struct Session * get_session (struct MHD_Connection *connection) { struct Session *ret; const char *cookie; cookie = MHD_lookup_connection_value (connection, MHD_COOKIE_KIND, COOKIE_NAME); if (cookie != NULL) { /* find existing session */ ret = sessions; while (NULL != ret) { if (0 == strcmp (cookie, ret->sid)) break; ret = ret->next; } if (NULL != ret) { ret->rc++; return ret; } } /* create fresh session */ ret = calloc (1, sizeof (struct Session)); if (NULL == ret) { fprintf (stderr, "calloc error: %s\n", strerror (errno)); return NULL; } /* not a super-secure way to generate a random session ID, but should do for a simple example... */ snprintf (ret->sid, sizeof (ret->sid), "%X%X%X%X", (unsigned int) rand (), (unsigned int) rand (), (unsigned int) rand (), (unsigned int) rand ()); ret->rc++; ret->start = time (NULL); ret->next = sessions; sessions = ret; return ret; } /** * Type of handler that generates a reply. * * @param cls content for the page (handler-specific) * @param mime mime type to use * @param session session information * @param connection connection to process * @param MHD_YES on success, MHD_NO on failure */ typedef int (*PageHandler)(const void *cls, const char *mime, struct Session *session, struct MHD_Connection *connection); /** * Entry we generate for each page served. */ struct Page { /** * Acceptable URL for this page. */ const char *url; /** * Mime type to set for the page. */ const char *mime; /** * Handler to call to generate response. */ PageHandler handler; /** * Extra argument to handler. */ const void *handler_cls; }; /** * Add header to response to set a session cookie. * * @param session session to use * @param response response to modify */ static void add_session_cookie (struct Session *session, struct MHD_Response *response) { char cstr[256]; snprintf (cstr, sizeof (cstr), "%s=%s", COOKIE_NAME, session->sid); if (MHD_NO == MHD_add_response_header (response, MHD_HTTP_HEADER_SET_COOKIE, cstr)) { fprintf (stderr, "Failed to set session cookie header!\n"); } } /** * Handler that returns a simple static HTTP page that * is passed in via 'cls'. * * @param cls a 'const char *' with the HTML webpage to return * @param mime mime type to use * @param session session handle * @param connection connection to use */ static int serve_simple_form (const void *cls, const char *mime, struct Session *session, struct MHD_Connection *connection) { int ret; const char *form = cls; struct MHD_Response *response; /* return static form */ response = MHD_create_response_from_buffer (strlen (form), (void *) form, MHD_RESPMEM_PERSISTENT); if (NULL == response) return MHD_NO; add_session_cookie (session, response); MHD_add_response_header (response, MHD_HTTP_HEADER_CONTENT_ENCODING, mime); ret = MHD_queue_response (connection, MHD_HTTP_OK, response); MHD_destroy_response (response); return ret; } /** * Handler that adds the 'v1' value to the given HTML code. * * @param cls unused * @param mime mime type to use * @param session session handle * @param connection connection to use */ static int fill_v1_form (const void *cls, const char *mime, struct Session *session, struct MHD_Connection *connection) { int ret; size_t slen; char *reply; struct MHD_Response *response; (void)cls; /* Unused. Silent compiler warning. */ slen = strlen (MAIN_PAGE) + strlen (session->value_1); reply = malloc (slen + 1); if (NULL == reply) return MHD_NO; snprintf (reply, slen + 1, MAIN_PAGE, session->value_1); /* return static form */ response = MHD_create_response_from_buffer (slen, (void *) reply, MHD_RESPMEM_MUST_FREE); if (NULL == response) { free (reply); return MHD_NO; } add_session_cookie (session, response); MHD_add_response_header (response, MHD_HTTP_HEADER_CONTENT_ENCODING, mime); ret = MHD_queue_response (connection, MHD_HTTP_OK, response); MHD_destroy_response (response); return ret; } /** * Handler that adds the 'v1' and 'v2' values to the given HTML code. * * @param cls unused * @param mime mime type to use * @param session session handle * @param connection connection to use */ static int fill_v1_v2_form (const void *cls, const char *mime, struct Session *session, struct MHD_Connection *connection) { int ret; char *reply; struct MHD_Response *response; size_t slen; (void)cls; /* Unused. Silent compiler warning. */ slen = strlen (SECOND_PAGE) + strlen (session->value_1) + strlen (session->value_2); reply = malloc (slen + 1); if (NULL == reply) return MHD_NO; snprintf (reply, slen + 1, SECOND_PAGE, session->value_1, session->value_2); /* return static form */ response = MHD_create_response_from_buffer (slen, (void *) reply, MHD_RESPMEM_MUST_FREE); if (NULL == response) { free (reply); return MHD_NO; } add_session_cookie (session, response); MHD_add_response_header (response, MHD_HTTP_HEADER_CONTENT_ENCODING, mime); ret = MHD_queue_response (connection, MHD_HTTP_OK, response); MHD_destroy_response (response); return ret; } /** * Handler used to generate a 404 reply. * * @param cls a 'const char *' with the HTML webpage to return * @param mime mime type to use * @param session session handle * @param connection connection to use */ static int not_found_page (const void *cls, const char *mime, struct Session *session, struct MHD_Connection *connection) { int ret; struct MHD_Response *response; (void)cls; /* Unused. Silent compiler warning. */ (void)session; /* Unused. Silent compiler warning. */ /* unsupported HTTP method */ response = MHD_create_response_from_buffer (strlen (NOT_FOUND_ERROR), (void *) NOT_FOUND_ERROR, MHD_RESPMEM_PERSISTENT); if (NULL == response) return MHD_NO; ret = MHD_queue_response (connection, MHD_HTTP_NOT_FOUND, response); MHD_add_response_header (response, MHD_HTTP_HEADER_CONTENT_ENCODING, mime); MHD_destroy_response (response); return ret; } /** * List of all pages served by this HTTP server. */ static struct Page pages[] = { { "/", "text/html", &fill_v1_form, NULL }, { "/2", "text/html", &fill_v1_v2_form, NULL }, { "/S", "text/html", &serve_simple_form, SUBMIT_PAGE }, { "/F", "text/html", &serve_simple_form, LAST_PAGE }, { NULL, NULL, ¬_found_page, NULL } /* 404 */ }; /** * 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 * @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 post_iterator (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 Request *request = cls; struct Session *session = request->session; (void)kind; /* Unused. Silent compiler warning. */ (void)filename; /* Unused. Silent compiler warning. */ (void)content_type; /* Unused. Silent compiler warning. */ (void)transfer_encoding; /* Unused. Silent compiler warning. */ if (0 == strcmp ("DONE", key)) { fprintf (stdout, "Session `%s' submitted `%s', `%s'\n", session->sid, session->value_1, session->value_2); return MHD_YES; } if (0 == strcmp ("v1", key)) { if (size + off >= sizeof(session->value_1)) size = sizeof (session->value_1) - off - 1; memcpy (&session->value_1[off], data, size); session->value_1[size+off] = '\0'; return MHD_YES; } if (0 == strcmp ("v2", key)) { if (size + off >= sizeof(session->value_2)) size = sizeof (session->value_2) - off - 1; memcpy (&session->value_2[off], data, size); session->value_2[size+off] = '\0'; return MHD_YES; } fprintf (stderr, "Unsupported form value `%s'\n", key); return MHD_YES; } /** * Main MHD callback for handling requests. * * @param cls argument given together with the function * pointer when the handler was registered with MHD * @param connection handle identifying the incoming connection * @param url the requested url * @param method the HTTP method used ("GET", "PUT", etc.) * @param version the HTTP version string (i.e. "HTTP/1.1") * @param upload_data the data being uploaded (excluding HEADERS, * for a POST that fits into memory and that is encoded * with a supported encoding, the POST data will NOT be * given in upload_data and is instead available as * part of MHD_get_connection_values; very large POST * data *will* be made available incrementally in * upload_data) * @param upload_data_size set initially to the size of the * upload_data provided; the method must update this * value to the number of bytes NOT processed; * @param ptr pointer that the callback can set to some * address and that will be preserved by MHD for future * calls for this request; since the access handler may * be called many times (i.e., for a PUT/POST operation * with plenty of upload data) this allows the application * to easily associate some request-specific state. * If necessary, this state can be cleaned up in the * global "MHD_RequestCompleted" callback (which * can be set with the MHD_OPTION_NOTIFY_COMPLETED). * Initially, *con_cls will be NULL. * @return MHS_YES if the connection was handled successfully, * MHS_NO if the socket must be closed due to a serios * error while handling the request */ static int create_response (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; struct Request *request; struct Session *session; int ret; unsigned int i; (void)cls; /* Unused. Silent compiler warning. */ (void)version; /* Unused. Silent compiler warning. */ request = *ptr; if (NULL == request) { request = calloc (1, sizeof (struct Request)); if (NULL == request) { fprintf (stderr, "calloc error: %s\n", strerror (errno)); return MHD_NO; } *ptr = request; if (0 == strcmp (method, MHD_HTTP_METHOD_POST)) { request->pp = MHD_create_post_processor (connection, 1024, &post_iterator, request); if (NULL == request->pp) { fprintf (stderr, "Failed to setup post processor for `%s'\n", url); return MHD_NO; /* internal error */ } } return MHD_YES; } if (NULL == request->session) { request->session = get_session (connection); if (NULL == request->session) { fprintf (stderr, "Failed to setup session for `%s'\n", url); return MHD_NO; /* internal error */ } } session = request->session; session->start = time (NULL); if (0 == strcmp (method, MHD_HTTP_METHOD_POST)) { /* evaluate POST data */ MHD_post_process (request->pp, upload_data, *upload_data_size); if (0 != *upload_data_size) { *upload_data_size = 0; return MHD_YES; } /* done with POST data, serve response */ MHD_destroy_post_processor (request->pp); request->pp = NULL; method = MHD_HTTP_METHOD_GET; /* fake 'GET' */ if (NULL != request->post_url) url = request->post_url; } if ( (0 == strcmp (method, MHD_HTTP_METHOD_GET)) || (0 == strcmp (method, MHD_HTTP_METHOD_HEAD)) ) { /* find out which page to serve */ i=0; while ( (pages[i].url != NULL) && (0 != strcmp (pages[i].url, url)) ) i++; ret = pages[i].handler (pages[i].handler_cls, pages[i].mime, session, connection); if (ret != MHD_YES) fprintf (stderr, "Failed to create page for `%s'\n", url); return ret; } /* unsupported HTTP method */ response = MHD_create_response_from_buffer (strlen (METHOD_ERROR), (void *) METHOD_ERROR, MHD_RESPMEM_PERSISTENT); ret = MHD_queue_response (connection, MHD_HTTP_NOT_ACCEPTABLE, response); MHD_destroy_response (response); return ret; } /** * Callback called upon completion of a request. * Decrements session reference counter. * * @param cls not used * @param connection connection that completed * @param con_cls session handle * @param toe status code */ static void request_completed_callback (void *cls, struct MHD_Connection *connection, void **con_cls, enum MHD_RequestTerminationCode toe) { struct Request *request = *con_cls; (void)cls; /* Unused. Silent compiler warning. */ (void)connection; /* Unused. Silent compiler warning. */ (void)toe; /* Unused. Silent compiler warning. */ if (NULL == request) return; if (NULL != request->session) request->session->rc--; if (NULL != request->pp) MHD_destroy_post_processor (request->pp); free (request); } /** * Clean up handles of sessions that have been idle for * too long. */ static void expire_sessions () { struct Session *pos; struct Session *prev; struct Session *next; time_t now; now = time (NULL); prev = NULL; pos = sessions; while (NULL != pos) { next = pos->next; if (now - pos->start > 60 * 60) { /* expire sessions after 1h */ if (NULL == prev) sessions = pos->next; else prev->next = next; free (pos); } else prev = pos; pos = next; } } /** * Call with the port number as the only argument. * Never terminates (other than by signals, such as CTRL-C). */ int main (int argc, char *const *argv) { struct MHD_Daemon *d; struct timeval tv; struct timeval *tvp; fd_set rs; fd_set ws; fd_set es; MHD_socket max; MHD_UNSIGNED_LONG_LONG mhd_timeout; if (argc != 2) { printf ("%s PORT\n", argv[0]); return 1; } /* initialize PRNG */ srand ((unsigned int) time (NULL)); d = MHD_start_daemon (MHD_USE_ERROR_LOG, atoi (argv[1]), NULL, NULL, &create_response, NULL, MHD_OPTION_CONNECTION_TIMEOUT, (unsigned int) 15, MHD_OPTION_NOTIFY_COMPLETED, &request_completed_callback, NULL, MHD_OPTION_END); if (NULL == d) return 1; while (1) { expire_sessions (); max = 0; FD_ZERO (&rs); FD_ZERO (&ws); FD_ZERO (&es); if (MHD_YES != MHD_get_fdset (d, &rs, &ws, &es, &max)) break; /* fatal internal error */ if (MHD_get_timeout (d, &mhd_timeout) == MHD_YES) { tv.tv_sec = mhd_timeout / 1000; tv.tv_usec = (mhd_timeout - (tv.tv_sec * 1000)) * 1000; tvp = &tv; } else tvp = NULL; if (-1 == select (max + 1, &rs, &ws, &es, tvp)) { if (EINTR != errno) abort (); } MHD_run (d); } MHD_stop_daemon (d); return 0; }