• Home
  • Line#
  • Scopes#
  • Navigate#
  • Raw
  • Download
1 /*
2  * libwebsockets - small server side websockets and web server implementation
3  *
4  * Copyright (C) 2010 - 2019 Andy Green <andy@warmcat.com>
5  *
6  * Permission is hereby granted, free of charge, to any person obtaining a copy
7  * of this software and associated documentation files (the "Software"), to
8  * deal in the Software without restriction, including without limitation the
9  * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
10  * sell copies of the Software, and to permit persons to whom the Software is
11  * furnished to do so, subject to the following conditions:
12  *
13  * The above copyright notice and this permission notice shall be included in
14  * all copies or substantial portions of the Software.
15  *
16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
19  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
21  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
22  * IN THE SOFTWARE.
23  */
24 
25 #if defined(LWS_WITH_SPAWN)
26 
27 #if defined(WIN32) || defined(_WIN32)
28 #else
29 #include <sys/wait.h>
30 #include <sys/times.h>
31 #endif
32 #endif
33 
34 /** \defgroup misc Miscellaneous APIs
35 * ##Miscellaneous APIs
36 *
37 * Various APIs outside of other categories
38 */
39 ///@{
40 
41 struct lws_buflist;
42 
43 /**
44  * lws_buflist_append_segment(): add buffer to buflist at head
45  *
46  * \param head: list head
47  * \param buf: buffer to stash
48  * \param len: length of buffer to stash
49  *
50  * Returns -1 on OOM, 1 if this was the first segment on the list, and 0 if
51  * it was a subsequent segment.
52  */
53 LWS_VISIBLE LWS_EXTERN int LWS_WARN_UNUSED_RESULT
54 lws_buflist_append_segment(struct lws_buflist **head, const uint8_t *buf,
55 			   size_t len);
56 /**
57  * lws_buflist_next_segment_len(): number of bytes left in current segment
58  *
59  * \param head: list head
60  * \param buf: if non-NULL, *buf is written with the address of the start of
61  *		the remaining data in the segment
62  *
63  * Returns the number of bytes left in the current segment.  0 indicates
64  * that the buflist is empty (there are no segments on the buflist).
65  */
66 LWS_VISIBLE LWS_EXTERN size_t
67 lws_buflist_next_segment_len(struct lws_buflist **head, uint8_t **buf);
68 
69 /**
70  * lws_buflist_use_segment(): remove len bytes from the current segment
71  *
72  * \param head: list head
73  * \param len: number of bytes to mark as used
74  *
75  * If len is less than the remaining length of the current segment, the position
76  * in the current segment is simply advanced and it returns.
77  *
78  * If len uses up the remaining length of the current segment, then the segment
79  * is deleted and the list head moves to the next segment if any.
80  *
81  * Returns the number of bytes left in the current segment.  0 indicates
82  * that the buflist is empty (there are no segments on the buflist).
83  */
84 LWS_VISIBLE LWS_EXTERN size_t
85 lws_buflist_use_segment(struct lws_buflist **head, size_t len);
86 
87 /**
88  * lws_buflist_total_len(): Get the total size of the buflist
89  *
90  * \param head: list head
91  *
92  * Returns the total number of bytes held on all segments of the buflist
93  */
94 LWS_VISIBLE LWS_EXTERN size_t
95 lws_buflist_total_len(struct lws_buflist **head);
96 
97 /**
98  * lws_buflist_linear_copy(): copy everything out as one without consuming
99  *
100  * \param head: list head
101  * \param ofs: start offset into buflist in bytes
102  * \param buf: buffer to copy linearly into
103  * \param len: length of buffer available
104  *
105  * Returns -1 if len is too small, or bytes copied.  Happy to do partial
106  * copies, returns 0 when there are no more bytes to copy.
107  */
108 LWS_VISIBLE LWS_EXTERN int
109 lws_buflist_linear_copy(struct lws_buflist **head, size_t ofs, uint8_t *buf,
110 			size_t len);
111 
112 /**
113  * lws_buflist_destroy_all_segments(): free all segments on the list
114  *
115  * \param head: list head
116  *
117  * This frees everything on the list unconditionally.  *head is always
118  * NULL after this.
119  */
120 LWS_VISIBLE LWS_EXTERN void
121 lws_buflist_destroy_all_segments(struct lws_buflist **head);
122 
123 /**
124  * lws_buflist_describe(): debug helper logging buflist status
125  *
126  * \param head: list head
127  * \param id: pointer shown in debug list
128  * \param reason: reason string show in debug list
129  *
130  * Iterates through the buflist segments showing position and size.
131  * This only exists when lws was built in debug mode
132  */
133 LWS_VISIBLE LWS_EXTERN void
134 lws_buflist_describe(struct lws_buflist **head, void *id, const char *reason);
135 
136 /**
137  * lws_ptr_diff(): helper to report distance between pointers as an int
138  *
139  * \param head: the pointer with the larger address
140  * \param tail: the pointer with the smaller address
141  *
142  * This helper gives you an int representing the number of bytes further
143  * forward the first pointer is compared to the second pointer.
144  */
145 #define lws_ptr_diff(head, tail) \
146 			((int)((char *)(head) - (char *)(tail)))
147 
148 /**
149  * lws_snprintf(): snprintf that truncates the returned length too
150  *
151  * \param str: destination buffer
152  * \param size: bytes left in destination buffer
153  * \param format: format string
154  * \param ...: args for format
155  *
156  * This lets you correctly truncate buffers by concatenating lengths, if you
157  * reach the limit the reported length doesn't exceed the limit.
158  */
159 LWS_VISIBLE LWS_EXTERN int
160 lws_snprintf(char *str, size_t size, const char *format, ...) LWS_FORMAT(3);
161 
162 /**
163  * lws_strncpy(): strncpy that guarantees NUL on truncated copy
164  *
165  * \param dest: destination buffer
166  * \param src: source buffer
167  * \param size: bytes left in destination buffer
168  *
169  * This lets you correctly truncate buffers by concatenating lengths, if you
170  * reach the limit the reported length doesn't exceed the limit.
171  */
172 LWS_VISIBLE LWS_EXTERN char *
173 lws_strncpy(char *dest, const char *src, size_t size);
174 
175 /*
176  * Variation where we want to use the smaller of two lengths, useful when the
177  * source string is not NUL terminated
178  */
179 #define lws_strnncpy(dest, src, size1, destsize) \
180 	lws_strncpy(dest, src, (size_t)(size1 + 1) < (size_t)(destsize) ? \
181 				(size_t)(size1 + 1) : (size_t)(destsize))
182 
183 /**
184  * lws_hex_to_byte_array(): convert hex string like 0123456789ab into byte data
185  *
186  * \param h: incoming NUL-terminated hex string
187  * \param dest: array to fill with binary decodes of hex pairs from h
188  * \param max: maximum number of bytes dest can hold, must be at least half
189  *		the size of strlen(h)
190  *
191  * This converts hex strings into an array of 8-bit representations, ie the
192  * input "abcd" produces two bytes of value 0xab and 0xcd.
193  *
194  * Returns number of bytes produced into \p dest, or -1 on error.
195  *
196  * Errors include non-hex chars and an odd count of hex chars in the input
197  * string.
198  */
199 LWS_VISIBLE LWS_EXTERN int
200 lws_hex_to_byte_array(const char *h, uint8_t *dest, int max);
201 
202 /*
203  * lws_timingsafe_bcmp(): constant time memcmp
204  *
205  * \param a: first buffer
206  * \param b: second buffer
207  * \param len: count of bytes to compare
208  *
209  * Return 0 if the two buffers are the same, else nonzero.
210  *
211  * Always compares all of the buffer before returning, so it can't be used as
212  * a timing oracle.
213  */
214 
215 LWS_VISIBLE LWS_EXTERN int
216 lws_timingsafe_bcmp(const void *a, const void *b, uint32_t len);
217 
218 /**
219  * lws_get_random(): fill a buffer with platform random data
220  *
221  * \param context: the lws context
222  * \param buf: buffer to fill
223  * \param len: how much to fill
224  *
225  * Fills buf with len bytes of random.  Returns the number of bytes set, if
226  * not equal to len, then getting the random failed.
227  */
228 LWS_VISIBLE LWS_EXTERN size_t
229 lws_get_random(struct lws_context *context, void *buf, size_t len);
230 /**
231  * lws_daemonize(): make current process run in the background
232  *
233  * \param _lock_path: the filepath to write the lock file
234  *
235  * Spawn lws as a background process, taking care of various things
236  */
237 LWS_VISIBLE LWS_EXTERN int LWS_WARN_UNUSED_RESULT
238 lws_daemonize(const char *_lock_path);
239 /**
240  * lws_get_library_version(): return string describing the version of lws
241  *
242  * On unix, also includes the git describe
243  */
244 LWS_VISIBLE LWS_EXTERN const char * LWS_WARN_UNUSED_RESULT
245 lws_get_library_version(void);
246 
247 /**
248  * lws_wsi_user() - get the user data associated with the connection
249  * \param wsi: lws connection
250  *
251  * Not normally needed since it's passed into the callback
252  */
253 LWS_VISIBLE LWS_EXTERN void *
254 lws_wsi_user(struct lws *wsi);
255 
256 /**
257  * lws_set_wsi_user() - set the user data associated with the client connection
258  * \param wsi: lws connection
259  * \param user: user data
260  *
261  * By default lws allocates this and it's not legal to externally set it
262  * yourself.  However client connections may have it set externally when the
263  * connection is created... if so, this api can be used to modify it at
264  * runtime additionally.
265  */
266 LWS_VISIBLE LWS_EXTERN void
267 lws_set_wsi_user(struct lws *wsi, void *user);
268 
269 /**
270  * lws_parse_uri:	cut up prot:/ads:port/path into pieces
271  *			Notice it does so by dropping '\0' into input string
272  *			and the leading / on the path is consequently lost
273  *
274  * \param p:			incoming uri string.. will get written to
275  * \param prot:		result pointer for protocol part (https://)
276  * \param ads:		result pointer for address part
277  * \param port:		result pointer for port part
278  * \param path:		result pointer for path part
279  *
280  * You may also refer to unix socket addresses, using a '+' at the start of
281  * the address.  In this case, the address should end with ':', which is
282  * treated as the separator between the address and path (the normal separator
283  * '/' is a valid part of the socket path).  Eg,
284  *
285  * http://+/var/run/mysocket:/my/path
286  *
287  * If the first character after the + is '@', it's interpreted by lws client
288  * processing as meaning to use linux abstract namespace sockets, the @ is
289  * replaced with a '\0' before use.
290  */
291 LWS_VISIBLE LWS_EXTERN int LWS_WARN_UNUSED_RESULT
292 lws_parse_uri(char *p, const char **prot, const char **ads, int *port,
293 	      const char **path);
294 /**
295  * lws_cmdline_option():	simple commandline parser
296  *
297  * \param argc:		count of argument strings
298  * \param argv:		argument strings
299  * \param val:		string to find
300  *
301  * Returns NULL if the string \p val is not found in the arguments.
302  *
303  * If it is found, then it returns a pointer to the next character after \p val.
304  * So if \p val is "-d", then for the commandlines "myapp -d15" and
305  * "myapp -d 15", in both cases the return will point to the "15".
306  *
307  * In the case there is no argument, like "myapp -d", the return will
308  * either point to the '\\0' at the end of -d, or to the start of the
309  * next argument, ie, will be non-NULL.
310  */
311 LWS_VISIBLE LWS_EXTERN const char *
312 lws_cmdline_option(int argc, const char **argv, const char *val);
313 
314 /**
315  * lws_cmdline_option_handle_builtin(): apply standard cmdline options
316  *
317  * \param argc:		count of argument strings
318  * \param argv:		argument strings
319  * \param info:		context creation info
320  *
321  * Applies standard options to the context creation info to save them having
322  * to be (unevenly) copied into the minimal examples.
323  *
324  * Applies default log levels that can be overriden by -d
325  */
326 LWS_VISIBLE LWS_EXTERN void
327 lws_cmdline_option_handle_builtin(int argc, const char **argv,
328 				  struct lws_context_creation_info *info);
329 
330 /**
331  * lws_now_secs(): return seconds since 1970-1-1
332  */
333 LWS_VISIBLE LWS_EXTERN unsigned long
334 lws_now_secs(void);
335 
336 /**
337  * lws_now_usecs(): return useconds since 1970-1-1
338  */
339 LWS_VISIBLE LWS_EXTERN lws_usec_t
340 lws_now_usecs(void);
341 
342 /**
343  * lws_get_context - Allow getting lws_context from a Websocket connection
344  * instance
345  *
346  * With this function, users can access context in the callback function.
347  * Otherwise users may have to declare context as a global variable.
348  *
349  * \param wsi:	Websocket connection instance
350  */
351 LWS_VISIBLE LWS_EXTERN struct lws_context * LWS_WARN_UNUSED_RESULT
352 lws_get_context(const struct lws *wsi);
353 
354 /**
355  * lws_get_vhost_listen_port - Find out the port number a vhost is listening on
356  *
357  * In the case you passed 0 for the port number at context creation time, you
358  * can discover the port number that was actually chosen for the vhost using
359  * this api.
360  *
361  * \param vhost:	Vhost to get listen port from
362  */
363 LWS_VISIBLE LWS_EXTERN int LWS_WARN_UNUSED_RESULT
364 lws_get_vhost_listen_port(struct lws_vhost *vhost);
365 
366 /**
367  * lws_get_count_threads(): how many service threads the context uses
368  *
369  * \param context: the lws context
370  *
371  * By default this is always 1, if you asked for more than lws can handle it
372  * will clip the number of threads.  So you can use this to find out how many
373  * threads are actually in use.
374  */
375 LWS_VISIBLE LWS_EXTERN int LWS_WARN_UNUSED_RESULT
376 lws_get_count_threads(struct lws_context *context);
377 
378 /**
379  * lws_get_parent() - get parent wsi or NULL
380  * \param wsi: lws connection
381  *
382  * Specialized wsi like cgi stdin/out/err are associated to a parent wsi,
383  * this allows you to get their parent.
384  */
385 LWS_VISIBLE LWS_EXTERN struct lws * LWS_WARN_UNUSED_RESULT
386 lws_get_parent(const struct lws *wsi);
387 
388 /**
389  * lws_get_child() - get child wsi or NULL
390  * \param wsi: lws connection
391  *
392  * Allows you to find a related wsi from the parent wsi.
393  */
394 LWS_VISIBLE LWS_EXTERN struct lws * LWS_WARN_UNUSED_RESULT
395 lws_get_child(const struct lws *wsi);
396 
397 /**
398  * lws_get_effective_uid_gid() - find out eventual uid and gid while still root
399  *
400  * \param context: lws context
401  * \param uid: pointer to uid result
402  * \param gid: pointer to gid result
403  *
404  * This helper allows you to find out what the uid and gid for the process will
405  * be set to after the privileges are dropped, beforehand.  So while still root,
406  * eg in LWS_CALLBACK_PROTOCOL_INIT, you can arrange things like cache dir
407  * and subdir creation / permissions down /var/cache dynamically.
408  */
409 LWS_VISIBLE LWS_EXTERN void
410 lws_get_effective_uid_gid(struct lws_context *context, int *uid, int *gid);
411 
412 /**
413  * lws_get_udp() - get wsi's udp struct
414  *
415  * \param wsi: lws connection
416  *
417  * Returns NULL or pointer to the wsi's UDP-specific information
418  */
419 LWS_VISIBLE LWS_EXTERN const struct lws_udp * LWS_WARN_UNUSED_RESULT
420 lws_get_udp(const struct lws *wsi);
421 
422 LWS_VISIBLE LWS_EXTERN void *
423 lws_get_opaque_parent_data(const struct lws *wsi);
424 
425 LWS_VISIBLE LWS_EXTERN void
426 lws_set_opaque_parent_data(struct lws *wsi, void *data);
427 
428 LWS_VISIBLE LWS_EXTERN void *
429 lws_get_opaque_user_data(const struct lws *wsi);
430 
431 LWS_VISIBLE LWS_EXTERN void
432 lws_set_opaque_user_data(struct lws *wsi, void *data);
433 
434 LWS_VISIBLE LWS_EXTERN int
435 lws_get_child_pending_on_writable(const struct lws *wsi);
436 
437 LWS_VISIBLE LWS_EXTERN void
438 lws_clear_child_pending_on_writable(struct lws *wsi);
439 
440 LWS_VISIBLE LWS_EXTERN int
441 lws_get_close_length(struct lws *wsi);
442 
443 LWS_VISIBLE LWS_EXTERN unsigned char *
444 lws_get_close_payload(struct lws *wsi);
445 
446 /**
447  * lws_get_network_wsi() - Returns wsi that has the tcp connection for this wsi
448  *
449  * \param wsi: wsi you have
450  *
451  * Returns wsi that has the tcp connection (which may be the incoming wsi)
452  *
453  * HTTP/1 connections will always return the incoming wsi
454  * HTTP/2 connections may return a different wsi that has the tcp connection
455  */
456 LWS_VISIBLE LWS_EXTERN
457 struct lws *lws_get_network_wsi(struct lws *wsi);
458 
459 /**
460  * lws_set_allocator() - custom allocator support
461  *
462  * \param realloc
463  *
464  * Allows you to replace the allocator (and deallocator) used by lws
465  */
466 LWS_VISIBLE LWS_EXTERN void
467 lws_set_allocator(void *(*realloc)(void *ptr, size_t size, const char *reason));
468 
469 enum {
470 	/*
471 	 * Flags for enable and disable rxflow with reason bitmap and with
472 	 * backwards-compatible single bool
473 	 */
474 	LWS_RXFLOW_REASON_USER_BOOL		= (1 << 0),
475 	LWS_RXFLOW_REASON_HTTP_RXBUFFER		= (1 << 6),
476 	LWS_RXFLOW_REASON_H2_PPS_PENDING	= (1 << 7),
477 
478 	LWS_RXFLOW_REASON_APPLIES		= (1 << 14),
479 	LWS_RXFLOW_REASON_APPLIES_ENABLE_BIT	= (1 << 13),
480 	LWS_RXFLOW_REASON_APPLIES_ENABLE	= LWS_RXFLOW_REASON_APPLIES |
481 						  LWS_RXFLOW_REASON_APPLIES_ENABLE_BIT,
482 	LWS_RXFLOW_REASON_APPLIES_DISABLE	= LWS_RXFLOW_REASON_APPLIES,
483 	LWS_RXFLOW_REASON_FLAG_PROCESS_NOW	= (1 << 12),
484 
485 };
486 
487 /**
488  * lws_rx_flow_control() - Enable and disable socket servicing for
489  *				received packets.
490  *
491  * If the output side of a server process becomes choked, this allows flow
492  * control for the input side.
493  *
494  * \param wsi:	Websocket connection instance to get callback for
495  * \param enable:	0 = disable read servicing for this connection, 1 = enable
496  *
497  * If you need more than one additive reason for rxflow control, you can give
498  * iLWS_RXFLOW_REASON_APPLIES_ENABLE or _DISABLE together with one or more of
499  * b5..b0 set to idicate which bits to enable or disable.  If any bits are
500  * enabled, rx on the connection is suppressed.
501  *
502  * LWS_RXFLOW_REASON_FLAG_PROCESS_NOW  flag may also be given to force any change
503  * in rxflowbstatus to benapplied immediately, this should be used when you are
504  * changing a wsi flow control state from outside a callback on that wsi.
505  */
506 LWS_VISIBLE LWS_EXTERN int
507 lws_rx_flow_control(struct lws *wsi, int enable);
508 
509 /**
510  * lws_rx_flow_allow_all_protocol() - Allow all connections with this protocol to receive
511  *
512  * When the user server code realizes it can accept more input, it can
513  * call this to have the RX flow restriction removed from all connections using
514  * the given protocol.
515  * \param context:	lws_context
516  * \param protocol:	all connections using this protocol will be allowed to receive
517  */
518 LWS_VISIBLE LWS_EXTERN void
519 lws_rx_flow_allow_all_protocol(const struct lws_context *context,
520 			       const struct lws_protocols *protocol);
521 
522 /**
523  * lws_remaining_packet_payload() - Bytes to come before "overall"
524  *					      rx fragment is complete
525  * \param wsi:		Websocket instance (available from user callback)
526  *
527  * This tracks how many bytes are left in the current ws fragment, according
528  * to the ws length given in the fragment header.
529  *
530  * If the message was in a single fragment, and there is no compression, this
531  * is the same as "how much data is left to read for this message".
532  *
533  * However, if the message is being sent in multiple fragments, this will
534  * reflect the unread amount of the current **fragment**, not the message.  With
535  * ws, it is legal to not know the length of the message before it completes.
536  *
537  * Additionally if the message is sent via the negotiated permessage-deflate
538  * extension, this number only tells the amount of **compressed** data left to
539  * be read, since that is the only information available at the ws layer.
540  */
541 LWS_VISIBLE LWS_EXTERN size_t
542 lws_remaining_packet_payload(struct lws *wsi);
543 
544 #if defined(LWS_WITH_DIR)
545 
546 typedef enum {
547 	LDOT_UNKNOWN,
548 	LDOT_FILE,
549 	LDOT_DIR,
550 	LDOT_LINK,
551 	LDOT_FIFO,
552 	LDOTT_SOCKET,
553 	LDOT_CHAR,
554 	LDOT_BLOCK
555 } lws_dir_obj_type_t;
556 
557 struct lws_dir_entry {
558 	const char *name;
559 	lws_dir_obj_type_t type;
560 };
561 
562 typedef int
563 lws_dir_callback_function(const char *dirpath, void *user,
564 			  struct lws_dir_entry *lde);
565 
566 /**
567  * lws_dir() - get a callback for everything in a directory
568  *
569  * \param dirpath: the directory to scan
570  * \param user: pointer to give to callback
571  * \param cb: callback to receive information on each file or dir
572  *
573  * Calls \p cb (with \p user) for every object in dirpath.
574  *
575  * This wraps whether it's using POSIX apis, or libuv (as needed for windows,
576  * since it refuses to support POSIX apis for this).
577  */
578 LWS_VISIBLE LWS_EXTERN int
579 lws_dir(const char *dirpath, void *user, lws_dir_callback_function cb);
580 #endif
581 
582 /**
583  * lws_get_allocated_heap() - if the platform supports it, returns amount of
584  *				heap allocated by lws itself
585  *
586  * On glibc currently, this reports the total amount of current logical heap
587  * allocation, found by tracking the amount allocated by lws_malloc() and
588  * friends and accounting for freed allocations via lws_free().
589  *
590  * This is useful for confirming where processwide heap allocations actually
591  * come from... this number represents all lws internal allocations, for
592  * fd tables, wsi allocations, ah, etc combined.  It doesn't include allocations
593  * from user code, since lws_malloc() etc are not exported from the library.
594  *
595  * On other platforms, it always returns 0.
596  */
597 size_t lws_get_allocated_heap(void);
598 
599 /**
600  * lws_get_tsi() - Get thread service index wsi belong to
601  * \param wsi:  websocket connection to check
602  *
603  * Returns more than zero (or zero if only one service thread as is the default).
604  */
605 LWS_VISIBLE LWS_EXTERN int
606 lws_get_tsi(struct lws *wsi);
607 
608 /**
609  * lws_is_ssl() - Find out if connection is using SSL
610  * \param wsi:	websocket connection to check
611  *
612  * Returns nonzero if the wsi is inside a tls tunnel, else zero.
613  */
614 LWS_VISIBLE LWS_EXTERN int
615 lws_is_ssl(struct lws *wsi);
616 /**
617  * lws_is_cgi() - find out if this wsi is running a cgi process
618  *
619  * \param wsi: lws connection
620  */
621 LWS_VISIBLE LWS_EXTERN int
622 lws_is_cgi(struct lws *wsi);
623 
624 /**
625  * lws_open() - platform-specific wrapper for open that prepares the fd
626  *
627  * \param __file: the filepath to open
628  * \param __oflag: option flags
629  *
630  * This is a wrapper around platform open() that sets options on the fd
631  * according to lws policy.  Currently that is FD_CLOEXEC to stop the opened
632  * fd being available to any child process forked by user code.
633  */
634 LWS_VISIBLE LWS_EXTERN int
635 lws_open(const char *__file, int __oflag, ...);
636 
637 struct lws_wifi_scan { /* generic wlan scan item */
638 	struct lws_wifi_scan *next;
639 	char ssid[32];
640 	int32_t rssi; /* divide by .count to get db */
641 	uint8_t bssid[6];
642 	uint8_t count;
643 	uint8_t channel;
644 	uint8_t authmode;
645 };
646 
647 #if defined(LWS_WITH_TLS) && !defined(LWS_WITH_MBEDTLS)
648 /**
649  * lws_get_ssl() - Return wsi's SSL context structure
650  * \param wsi:	websocket connection
651  *
652  * Returns pointer to the SSL library's context structure
653  */
654 LWS_VISIBLE LWS_EXTERN SSL*
655 lws_get_ssl(struct lws *wsi);
656 #endif
657 
658 LWS_VISIBLE LWS_EXTERN void
659 lws_explicit_bzero(void *p, size_t len);
660 
661 typedef struct lws_humanize_unit {
662 	const char *name; /* array ends with NULL name */
663 	uint64_t factor;
664 } lws_humanize_unit_t;
665 
666 LWS_VISIBLE LWS_EXTERN const lws_humanize_unit_t humanize_schema_si[7];
667 LWS_VISIBLE LWS_EXTERN const lws_humanize_unit_t humanize_schema_si_bytes[7];
668 LWS_VISIBLE LWS_EXTERN const lws_humanize_unit_t humanize_schema_us[8];
669 
670 /**
671  * lws_humanize() - Convert possibly large number to human-readable uints
672  *
673  * \param buf: result string buffer
674  * \param len: remaining length in \p buf
675  * \param value: the uint64_t value to represent
676  * \param schema: and array of scaling factors and units
677  *
678  * This produces a concise string representation of \p value, referencing the
679  * schema \p schema of scaling factors and units to find the smallest way to
680  * render it.
681  *
682  * Three schema are exported from lws for general use, humanize_schema_si, which
683  * represents as, eg, "  22.130Gi" or " 128      "; humanize_schema_si_bytes
684  * which is the same but shows, eg, "  22.130GiB", and humanize_schema_us,
685  * which represents a count of us as a human-readable time like "  14.350min",
686  * or "  1.500d".
687  *
688  * You can produce your own schema.
689  */
690 
691 LWS_VISIBLE LWS_EXTERN int
692 lws_humanize(char *buf, int len, uint64_t value,
693 	     const lws_humanize_unit_t *schema);
694 
695 LWS_VISIBLE LWS_EXTERN void
696 lws_ser_wu16be(uint8_t *b, uint16_t u);
697 
698 LWS_VISIBLE LWS_EXTERN void
699 lws_ser_wu32be(uint8_t *b, uint32_t u32);
700 
701 LWS_VISIBLE LWS_EXTERN void
702 lws_ser_wu64be(uint8_t *b, uint64_t u64);
703 
704 LWS_VISIBLE LWS_EXTERN uint16_t
705 lws_ser_ru16be(const uint8_t *b);
706 
707 LWS_VISIBLE LWS_EXTERN uint32_t
708 lws_ser_ru32be(const uint8_t *b);
709 
710 LWS_VISIBLE LWS_EXTERN uint64_t
711 lws_ser_ru64be(const uint8_t *b);
712 
713 LWS_VISIBLE LWS_EXTERN int
714 lws_vbi_encode(uint64_t value, void *buf);
715 
716 LWS_VISIBLE LWS_EXTERN int
717 lws_vbi_decode(const void *buf, uint64_t *value, size_t len);
718 
719 ///@}
720 
721 #if defined(LWS_WITH_SPAWN)
722 
723 /* opaque internal struct */
724 struct lws_spawn_piped;
725 
726 typedef void (*lsp_cb_t)(void *opaque, lws_usec_t *accounting, siginfo_t *si,
727 			 int we_killed_him);
728 
729 
730 /**
731  * lws_spawn_piped_info - details given to create a spawned pipe
732  *
733  * \p owner: lws_dll2_owner_t that lists all active spawns, or NULL
734  * \p vh: vhost to bind stdwsi to... from opt_parent if given
735  * \p opt_parent: optional parent wsi for stdwsi
736  * \p exec_array: argv for process to spawn
737  * \p env_array: environment for spawned process, NULL ends env list
738  * \p protocol_name: NULL, or vhost protocol name to bind stdwsi to
739  * \p chroot_path: NULL, or chroot patch for child process
740  * \p wd: working directory to cd to after fork, NULL defaults to /tmp
741  * \p plsp: NULL, or pointer to the outer lsp pointer so it can be set NULL when destroyed
742  * \p opaque: pointer passed to the reap callback, if any
743  * \p timeout: optional us-resolution timeout, or zero
744  * \p reap_cb: callback when child process has been reaped and the lsp destroyed
745  * \p tsi: tsi to bind stdwsi to... from opt_parent if given
746  */
747 struct lws_spawn_piped_info {
748 	struct lws_dll2_owner		*owner;
749 	struct lws_vhost		*vh;
750 	struct lws			*opt_parent;
751 
752 	const char * const		*exec_array;
753 	char				**env_array;
754 	const char			*protocol_name;
755 	const char			*chroot_path;
756 	const char			*wd;
757 
758 	struct lws_spawn_piped		**plsp;
759 
760 	void				*opaque;
761 
762 	lsp_cb_t			reap_cb;
763 
764 	lws_usec_t			timeout_us;
765 	int				max_log_lines;
766 	int				tsi;
767 
768 	const struct lws_role_ops	*ops; /* NULL is raw file */
769 
770 	uint8_t				disable_ctrlc;
771 };
772 
773 /**
774  * lws_spawn_piped() - spawn a child process with stdxxx redirected
775  *
776  * \p lspi: info struct describing details of spawn to create
777  *
778  * This spawns a child process managed in the lsp object and with attributes
779  * set in the arguments.  The stdin/out/err streams are redirected to pipes
780  * which are instantiated into wsi that become child wsi of \p parent if non-
781  * NULL.  .opaque_user_data on the stdwsi created is set to point to the
782  * lsp object, so this can be recovered easily in the protocol handler.
783  *
784  * If \p owner is non-NULL, successful spawns join the given dll2 owner in the
785  * original process.
786  *
787  * If \p timeout is non-zero, successful spawns register a sul with the us-
788  * resolution timeout to callback \p timeout_cb, in the original process.
789  *
790  * Returns 0 if the spawn went OK or nonzero if it failed and was cleaned up.
791  * The spawned process continues asynchronously and this will return after
792  * starting it if all went well.
793  */
794 LWS_VISIBLE LWS_EXTERN struct lws_spawn_piped *
795 lws_spawn_piped(const struct lws_spawn_piped_info *lspi);
796 
797 /*
798  * lws_spawn_piped_kill_child_process() - attempt to kill child process
799  *
800  * \p lsp: child object to kill
801  *
802  * Attempts to signal the child process in \p lsp to terminate.
803  */
804 LWS_VISIBLE LWS_EXTERN int
805 lws_spawn_piped_kill_child_process(struct lws_spawn_piped *lsp);
806 
807 /**
808  * lws_spawn_stdwsi_closed() - inform the spawn one of its stdxxx pipes closed
809  *
810  * \p lsp: the spawn object
811  *
812  * When you notice one of the spawn stdxxx pipes closed, inform the spawn
813  * instance using this api.  When it sees all three have closed, it will
814  * automatically try to reap the child process.
815  *
816  * This is the mechanism whereby the spawn object can understand its child
817  * has closed.
818  */
819 LWS_VISIBLE LWS_EXTERN void
820 lws_spawn_stdwsi_closed(struct lws_spawn_piped *lsp);
821 
822 /**
823  * lws_spawn_get_stdfd() - return std channel index for stdwsi
824  *
825  * \p wsi: the wsi
826  *
827  * If you know wsi is a stdwsi from a spawn, you can determine its original
828  * channel index / fd before the pipes replaced the default fds.  It will return
829  * one of 0 (STDIN), 1 (STDOUT) or 2 (STDERR).  You can handle all three in the
830  * same protocol handler and then disambiguate them using this api.
831  */
832 LWS_VISIBLE LWS_EXTERN int
833 lws_spawn_get_stdfd(struct lws *wsi);
834 
835 #endif
836 
837 struct lws_fsmount {
838 	const char	*layers_path;	/* where layers live */
839 	const char	*overlay_path;	/* where overlay instantiations live */
840 
841 	char		mp[256];	/* mountpoint path */
842 	char		ovname[64];	/* unique name for mount instance */
843 	char		distro[64];	/* unique name for layer source */
844 
845 #if defined(__linux__)
846 	const char	*layers[4];	/* distro layers, like "base", "env" */
847 #endif
848 };
849 
850 /**
851  * lws_fsmount_mount() - Mounts an overlayfs stack of layers
852  *
853  * \p fsm: struct lws_fsmount specifying the mount layout
854  *
855  * This api is able to assemble up to 4 layer directories on to a mountpoint
856  * using overlayfs mount (Linux only).
857  *
858  * Set fsm.layers_path to the base dir where the layers themselves live, the
859  * entries in fsm.layers[] specifies the relative path to the layer, comprising
860  * fsm.layers_path/fsm.distro/fsm.layers[], with [0] being the deepest, earliest
861  * layer and the rest being progressively on top of [0]; NULL indicates the
862  * layer is unused.
863  *
864  * fsm.overlay_path is the base path of the overlayfs instantiations... empty
865  * dirs must exist at
866  *
867  * fsm.overlay_path/overlays/fsm.ovname/work
868  * fsm.overlay_path/overlays/fsm.ovname/session
869  *
870  * Set fsm.mp to the path of an already-existing empty dir that will be the
871  * mountpoint, this can be whereever you like.
872  *
873  * Overlayfs merges the union of all the contributing layers at the mountpoint,
874  * the mount is writeable but the layer themselves are immutable, all additions
875  * and changes are stored in
876  *
877  * fsm.overlay_path/overlays/fsm.ovname/session
878  *
879  * Returns 0 if mounted OK, nonzero if errors.
880  *
881  * Retain fsm for use with unmounting.
882  */
883 LWS_VISIBLE LWS_EXTERN int
884 lws_fsmount_mount(struct lws_fsmount *fsm);
885 
886 /**
887  * lws_fsmount_unmount() - Unmounts an overlayfs dir
888  *
889  * \p fsm: struct lws_fsmount specifying the mount layout
890  *
891  * Unmounts the mountpoint in fsm.mp.
892  *
893  * Delete fsm.overlay_path/overlays/fsm.ovname/session to permanently eradicate
894  * all changes from the time the mountpoint was in use.
895  *
896  * Returns 0 if unmounted OK.
897  */
898 LWS_VISIBLE LWS_EXTERN int
899 lws_fsmount_unmount(struct lws_fsmount *fsm);
900