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1 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
2  * All rights reserved.
3  *
4  * This package is an SSL implementation written
5  * by Eric Young (eay@cryptsoft.com).
6  * The implementation was written so as to conform with Netscapes SSL.
7  *
8  * This library is free for commercial and non-commercial use as long as
9  * the following conditions are aheared to.  The following conditions
10  * apply to all code found in this distribution, be it the RC4, RSA,
11  * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
12  * included with this distribution is covered by the same copyright terms
13  * except that the holder is Tim Hudson (tjh@cryptsoft.com).
14  *
15  * Copyright remains Eric Young's, and as such any Copyright notices in
16  * the code are not to be removed.
17  * If this package is used in a product, Eric Young should be given attribution
18  * as the author of the parts of the library used.
19  * This can be in the form of a textual message at program startup or
20  * in documentation (online or textual) provided with the package.
21  *
22  * Redistribution and use in source and binary forms, with or without
23  * modification, are permitted provided that the following conditions
24  * are met:
25  * 1. Redistributions of source code must retain the copyright
26  *    notice, this list of conditions and the following disclaimer.
27  * 2. Redistributions in binary form must reproduce the above copyright
28  *    notice, this list of conditions and the following disclaimer in the
29  *    documentation and/or other materials provided with the distribution.
30  * 3. All advertising materials mentioning features or use of this software
31  *    must display the following acknowledgement:
32  *    "This product includes cryptographic software written by
33  *     Eric Young (eay@cryptsoft.com)"
34  *    The word 'cryptographic' can be left out if the rouines from the library
35  *    being used are not cryptographic related :-).
36  * 4. If you include any Windows specific code (or a derivative thereof) from
37  *    the apps directory (application code) you must include an acknowledgement:
38  *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
39  *
40  * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
41  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
42  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
43  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
44  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
45  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
46  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
47  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
48  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
49  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
50  * SUCH DAMAGE.
51  *
52  * The licence and distribution terms for any publically available version or
53  * derivative of this code cannot be changed.  i.e. this code cannot simply be
54  * copied and put under another distribution licence
55  * [including the GNU Public Licence.] */
56 
57 #ifndef OPENSSL_HEADER_BIO_H
58 #define OPENSSL_HEADER_BIO_H
59 
60 #include <openssl/base.h>
61 
62 #include <stdio.h>  /* For FILE */
63 
64 #include <openssl/err.h> /* for ERR_print_errors_fp */
65 #include <openssl/ex_data.h>
66 #include <openssl/stack.h>
67 #include <openssl/thread.h>
68 
69 #if defined(__cplusplus)
70 extern "C" {
71 #endif
72 
73 
74 /* BIO abstracts over a file-descriptor like interface. */
75 
76 
77 /* Allocation and freeing. */
78 
79 /* BIO_new creates a new BIO with the given type and a reference count of one.
80  * It returns the fresh |BIO|, or NULL on error. */
81 OPENSSL_EXPORT BIO *BIO_new(const BIO_METHOD *type);
82 
83 /* BIO_free decrements the reference count of |bio|. If the reference count
84  * drops to zero, it (optionally) calls the BIO's callback with |BIO_CB_FREE|,
85  * frees the ex_data and then, if the BIO has a destroy callback for the
86  * method, calls it. Finally it frees |bio| itself. It then repeats that for
87  * the next BIO in the chain, if any.
88  *
89  * It returns one on success or zero otherwise. */
90 OPENSSL_EXPORT int BIO_free(BIO *bio);
91 
92 /* BIO_vfree performs the same actions as |BIO_free|, but has a void return
93  * value. This is provided for API-compat.
94  *
95  * TODO(fork): remove. */
96 OPENSSL_EXPORT void BIO_vfree(BIO *bio);
97 
98 /* BIO_up_ref increments the reference count of |bio| and returns it. */
99 OPENSSL_EXPORT BIO *BIO_up_ref(BIO *bio);
100 
101 
102 /* Basic I/O. */
103 
104 /* BIO_read attempts to read |len| bytes into |data|. It returns the number of
105  * bytes read, zero on EOF, or a negative number on error. */
106 OPENSSL_EXPORT int BIO_read(BIO *bio, void *data, int len);
107 
108 /* BIO_gets "reads a line" from |bio| and puts at most |size| bytes into |buf|.
109  * It returns the number of bytes read or a negative number on error. The
110  * phrase "reads a line" is in quotes in the previous sentence because the
111  * exact operation depends on the BIO's method. For example, a digest BIO will
112  * return the digest in response to a |BIO_gets| call.
113  *
114  * TODO(fork): audit the set of BIOs that we end up needing. If all actually
115  * return a line for this call, remove the warning above. */
116 OPENSSL_EXPORT int BIO_gets(BIO *bio, char *buf, int size);
117 
118 /* BIO_write writes |len| bytes from |data| to BIO. It returns the number of
119  * bytes written or a negative number on error. */
120 OPENSSL_EXPORT int BIO_write(BIO *bio, const void *data, int len);
121 
122 /* BIO_puts writes a NUL terminated string from |buf| to |bio|. It returns the
123  * number of bytes written or a negative number on error. */
124 OPENSSL_EXPORT int BIO_puts(BIO *bio, const char *buf);
125 
126 /* BIO_flush flushes any buffered output. It returns one on success and zero
127  * otherwise. */
128 OPENSSL_EXPORT int BIO_flush(BIO *bio);
129 
130 
131 /* Low-level control functions.
132  *
133  * These are generic functions for sending control requests to a BIO. In
134  * general one should use the wrapper functions like |BIO_get_close|. */
135 
136 /* BIO_ctrl sends the control request |cmd| to |bio|. The |cmd| argument should
137  * be one of the |BIO_C_*| values. */
138 OPENSSL_EXPORT long BIO_ctrl(BIO *bio, int cmd, long larg, void *parg);
139 
140 /* BIO_ptr_ctrl acts like |BIO_ctrl| but passes the address of a |void*|
141  * pointer as |parg| and returns the value that is written to it, or NULL if
142  * the control request returns <= 0. */
143 OPENSSL_EXPORT char *BIO_ptr_ctrl(BIO *bp, int cmd, long larg);
144 
145 /* BIO_int_ctrl acts like |BIO_ctrl| but passes the address of a copy of |iarg|
146  * as |parg|. */
147 OPENSSL_EXPORT long BIO_int_ctrl(BIO *bp, int cmd, long larg, int iarg);
148 
149 /* BIO_reset resets |bio| to its initial state, the precise meaning of which
150  * depends on the concrete type of |bio|. It returns one on success and zero
151  * otherwise. */
152 OPENSSL_EXPORT int BIO_reset(BIO *bio);
153 
154 /* BIO_set_flags ORs |flags| with |bio->flags|. */
155 OPENSSL_EXPORT void BIO_set_flags(BIO *bio, int flags);
156 
157 /* BIO_test_flags returns |bio->flags| AND |flags|. */
158 OPENSSL_EXPORT int BIO_test_flags(const BIO *bio, int flags);
159 
160 /* BIO_should_read returns non-zero if |bio| encountered a temporary error
161  * while reading (i.e. EAGAIN), indicating that the caller should retry the
162  * read. */
163 OPENSSL_EXPORT int BIO_should_read(const BIO *bio);
164 
165 /* BIO_should_write returns non-zero if |bio| encountered a temporary error
166  * while writing (i.e. EAGAIN), indicating that the caller should retry the
167  * write. */
168 OPENSSL_EXPORT int BIO_should_write(const BIO *bio);
169 
170 /* BIO_should_retry returns non-zero if the reason that caused a failed I/O
171  * operation is temporary and thus the operation should be retried. Otherwise,
172  * it was a permanent error and it returns zero. */
173 OPENSSL_EXPORT int BIO_should_retry(const BIO *bio);
174 
175 /* BIO_should_io_special returns non-zero if |bio| encountered a temporary
176  * error while performing a special I/O operation, indicating that the caller
177  * should retry. The operation that caused the error is returned by
178  * |BIO_get_retry_reason|. */
179 OPENSSL_EXPORT int BIO_should_io_special(const BIO *bio);
180 
181 /* BIO_RR_SSL_X509_LOOKUP indicates that an SSL BIO blocked because the SSL
182  * library returned with SSL_ERROR_WANT_X509_LOOKUP.
183  *
184  * TODO(fork): remove. */
185 #define BIO_RR_SSL_X509_LOOKUP 0x01
186 
187 /* BIO_RR_CONNECT indicates that a connect would have blocked */
188 #define BIO_RR_CONNECT 0x02
189 
190 /* BIO_RR_ACCEPT indicates that an accept would have blocked */
191 #define BIO_RR_ACCEPT 0x03
192 
193 /* BIO_RR_SSL_CHANNEL_ID_LOOKUP indicates that the ChannelID code cannot find
194  * a private key for a TLS connection. */
195 #define BIO_RR_SSL_CHANNEL_ID_LOOKUP 0x04
196 
197 /* BIO_get_retry_reason returns the special I/O operation that needs to be
198  * retried. The return value is one of the |BIO_RR_*| values. */
199 OPENSSL_EXPORT int BIO_get_retry_reason(const BIO *bio);
200 
201 /* BIO_clear_flags ANDs |bio->flags| with the bitwise-complement of |flags|. */
202 OPENSSL_EXPORT void BIO_clear_flags(BIO *bio, int flags);
203 
204 /* BIO_set_retry_read sets the |BIO_FLAGS_READ| and |BIO_FLAGS_SHOULD_RETRY|
205  * flags on |bio|. */
206 OPENSSL_EXPORT void BIO_set_retry_read(BIO *bio);
207 
208 /* BIO_set_retry_write sets the |BIO_FLAGS_WRITE| and |BIO_FLAGS_SHOULD_RETRY|
209  * flags on |bio|. */
210 OPENSSL_EXPORT void BIO_set_retry_write(BIO *bio);
211 
212 /* BIO_get_retry_flags gets the |BIO_FLAGS_READ|, |BIO_FLAGS_WRITE|,
213  * |BIO_FLAGS_IO_SPECIAL| and |BIO_FLAGS_SHOULD_RETRY| flags from |bio|. */
214 OPENSSL_EXPORT int BIO_get_retry_flags(BIO *bio);
215 
216 /* BIO_clear_retry_flags clears the |BIO_FLAGS_READ|, |BIO_FLAGS_WRITE|,
217  * |BIO_FLAGS_IO_SPECIAL| and |BIO_FLAGS_SHOULD_RETRY| flags from |bio|. */
218 OPENSSL_EXPORT void BIO_clear_retry_flags(BIO *bio);
219 
220 /* BIO_method_type returns the type of |bio|, which is one of the |BIO_TYPE_*|
221  * values. */
222 OPENSSL_EXPORT int BIO_method_type(const BIO *bio);
223 
224 /* bio_info_cb is the type of a callback function that can be called for most
225  * BIO operations. The |event| argument is one of |BIO_CB_*| and can be ORed
226  * with |BIO_CB_RETURN| if the callback is being made after the operation in
227  * question. In that case, |return_value| will contain the return value from
228  * the operation. */
229 typedef long (*bio_info_cb)(BIO *bio, int event, const char *parg, int cmd,
230                             long larg, long return_value);
231 
232 /* BIO_callback_ctrl allows the callback function to be manipulated. The |cmd|
233  * arg will generally be |BIO_CTRL_SET_CALLBACK| but arbitary command values
234  * can be interpreted by the |BIO|. */
235 OPENSSL_EXPORT long BIO_callback_ctrl(BIO *bio, int cmd, bio_info_cb fp);
236 
237 /* BIO_pending returns the number of bytes pending to be read. */
238 OPENSSL_EXPORT size_t BIO_pending(const BIO *bio);
239 
240 /* BIO_ctrl_pending calls |BIO_pending| and exists only for compatibility with
241  * OpenSSL. */
242 OPENSSL_EXPORT size_t BIO_ctrl_pending(const BIO *bio);
243 
244 /* BIO_wpending returns the number of bytes pending to be written. */
245 OPENSSL_EXPORT size_t BIO_wpending(const BIO *bio);
246 
247 /* BIO_set_close sets the close flag for |bio|. The meaning of which depends on
248  * the type of |bio| but, for example, a memory BIO interprets the close flag
249  * as meaning that it owns its buffer. It returns one on success and zero
250  * otherwise. */
251 OPENSSL_EXPORT int BIO_set_close(BIO *bio, int close_flag);
252 
253 /* BIO_set_callback sets a callback function that will be called before and
254  * after most operations. See the comment above |bio_info_cb|. */
255 OPENSSL_EXPORT void BIO_set_callback(BIO *bio, bio_info_cb callback_func);
256 
257 /* BIO_set_callback_arg sets the opaque pointer value that can be read within a
258  * callback with |BIO_get_callback_arg|. */
259 OPENSSL_EXPORT void BIO_set_callback_arg(BIO *bio, char *arg);
260 
261 /* BIO_get_callback_arg returns the last value of the opaque callback pointer
262  * set by |BIO_set_callback_arg|. */
263 OPENSSL_EXPORT char *BIO_get_callback_arg(const BIO *bio);
264 
265 /* BIO_number_read returns the number of bytes that have been read from
266  * |bio|. */
267 OPENSSL_EXPORT size_t BIO_number_read(const BIO *bio);
268 
269 /* BIO_number_written returns the number of bytes that have been written to
270  * |bio|. */
271 OPENSSL_EXPORT size_t BIO_number_written(const BIO *bio);
272 
273 
274 /* Managing chains of BIOs.
275  *
276  * BIOs can be put into chains where the output of one is used as the input of
277  * the next etc. The most common case is a buffering BIO, which accepts and
278  * buffers writes until flushed into the next BIO in the chain. */
279 
280 /* BIO_push adds |appended_bio| to the end of the chain with |bio| at the head.
281  * It returns |bio|. Note that |appended_bio| may be the head of a chain itself
282  * and thus this function can be used to join two chains.
283  *
284  * BIO_push takes ownership of the caller's reference to |appended_bio|. */
285 OPENSSL_EXPORT BIO *BIO_push(BIO *bio, BIO *appended_bio);
286 
287 /* BIO_pop removes |bio| from the head of a chain and returns the next BIO in
288  * the chain, or NULL if there is no next BIO.
289  *
290  * The caller takes ownership of the chain's reference to |bio|. */
291 OPENSSL_EXPORT BIO *BIO_pop(BIO *bio);
292 
293 /* BIO_next returns the next BIO in the chain after |bio|, or NULL if there is
294  * no such BIO. */
295 OPENSSL_EXPORT BIO *BIO_next(BIO *bio);
296 
297 /* BIO_free_all calls |BIO_free|.
298  *
299  * TODO(fork): update callers and remove. */
300 OPENSSL_EXPORT void BIO_free_all(BIO *bio);
301 
302 /* BIO_find_type walks a chain of BIOs and returns the first that matches
303  * |type|, which is one of the |BIO_TYPE_*| values. */
304 OPENSSL_EXPORT BIO *BIO_find_type(BIO *bio, int type);
305 
306 /* BIO_copy_next_retry sets the retry flags and |retry_reason| of |bio| from
307  * the next BIO in the chain. */
308 OPENSSL_EXPORT void BIO_copy_next_retry(BIO *bio);
309 
310 
311 /* Printf functions.
312  *
313  * These functions are versions of printf functions that output to a BIO rather
314  * than a FILE. */
315 #ifdef __GNUC__
316 #define __bio_h__attr__ __attribute__
317 #else
318 #define __bio_h__attr__(x)
319 #endif
320 OPENSSL_EXPORT int BIO_printf(BIO *bio, const char *format, ...)
321     __bio_h__attr__((__format__(__printf__, 2, 3)));
322 #undef __bio_h__attr__
323 
324 
325 /* Utility functions. */
326 
327 /* BIO_indent prints min(|indent|, |max_indent|) spaces. It returns one on
328  * success and zero otherwise. */
329 OPENSSL_EXPORT int BIO_indent(BIO *bio, unsigned indent, unsigned max_indent);
330 
331 /* BIO_hexdump writes a hex dump of |data| to |bio|. Each line will be indented
332  * by |indent| spaces. */
333 OPENSSL_EXPORT int BIO_hexdump(BIO *bio, const uint8_t *data, size_t len,
334                                unsigned indent);
335 
336 /* BIO_print_errors prints the current contents of the error stack to |bio|
337  * using human readable strings where possible. */
338 OPENSSL_EXPORT void BIO_print_errors(BIO *bio);
339 
340 /* BIO_read_asn1 reads a single ASN.1 object from |bio|. If successful it sets
341  * |*out| to be an allocated buffer (that should be freed with |OPENSSL_free|),
342  * |*out_size| to the length, in bytes, of that buffer and returns one.
343  * Otherwise it returns zero.
344  *
345  * If the length of the object is greater than |max_len| or 2^32 then the
346  * function will fail. Long-form tags are not supported. If the length of the
347  * object is indefinite the full contents of |bio| are read, unless it would be
348  * greater than |max_len|, in which case the function fails.
349  *
350  * If the function fails then some unknown amount of data may have been read
351  * from |bio|. */
352 OPENSSL_EXPORT int BIO_read_asn1(BIO *bio, uint8_t **out, size_t *out_len,
353                                  size_t max_len);
354 
355 
356 /* Memory BIOs.
357  *
358  * Memory BIOs can be used as a read-only source (with |BIO_new_mem_buf|) or a
359  * writable sink (with |BIO_new|, |BIO_s_mem| and |BIO_get_mem_buf|). Data
360  * written to a writable, memory BIO can be recalled by reading from it.
361  *
362  * Calling |BIO_reset| on a read-only BIO resets it to the original contents.
363  * On a writable BIO, it clears any data.
364  *
365  * If the close flag is set to |BIO_NOCLOSE| (not the default) then the
366  * underlying |BUF_MEM| will not be freed when the |BIO| is freed.
367  *
368  * Memory BIOs support |BIO_gets| and |BIO_puts|.
369  *
370  * |BIO_eof| is true if no data is in the BIO.
371  *
372  * |BIO_ctrl_pending| returns the number of bytes currently stored. */
373 
374 /* BIO_s_mem returns a |BIO_METHOD| that uses a in-memory buffer. */
375 OPENSSL_EXPORT const BIO_METHOD *BIO_s_mem(void);
376 
377 /* BIO_new_mem_buf creates BIO that reads and writes from |len| bytes at |buf|.
378  * It does not take ownership of |buf|. It returns the BIO or NULL on error.
379  *
380  * If |len| is negative, then |buf| is treated as a NUL-terminated string, but
381  * don't depend on this in new code. */
382 OPENSSL_EXPORT BIO *BIO_new_mem_buf(void *buf, int len);
383 
384 /* BIO_mem_contents sets |*out_contents| to point to the current contents of
385  * |bio| and |*out_len| to contain the length of that data. It returns one on
386  * success and zero otherwise. */
387 OPENSSL_EXPORT int BIO_mem_contents(const BIO *bio,
388                                     const uint8_t **out_contents,
389                                     size_t *out_len);
390 
391 /* BIO_get_mem_data sets |*contents| to point to the current contents of |bio|
392  * and returns the length of the data.
393  *
394  * WARNING: don't use this, use |BIO_mem_contents|. A return value of zero from
395  * this function can mean either that it failed or that the memory buffer is
396  * empty. */
397 OPENSSL_EXPORT long BIO_get_mem_data(BIO *bio, char **contents);
398 
399 /* BIO_get_mem_ptr sets |*out| to a BUF_MEM containing the current contents of
400  * |bio|. It returns one on success or zero on error. */
401 OPENSSL_EXPORT int BIO_get_mem_ptr(BIO *bio, BUF_MEM **out);
402 
403 /* BIO_set_mem_buf sets |b| as the contents of |bio|. If |take_ownership| is
404  * non-zero, then |b| will be freed when |bio| is closed. Returns one on
405  * success or zero otherwise. */
406 OPENSSL_EXPORT int BIO_set_mem_buf(BIO *bio, BUF_MEM *b, int take_ownership);
407 
408 /* BIO_set_mem_eof_return sets the value that will be returned from reading
409  * |bio| when empty. If |eof_value| is zero then an empty memory BIO will
410  * return EOF (that is it will return zero and |BIO_should_retry| will be
411  * false). If |eof_value| is non zero then it will return |eof_value| when it
412  * is empty and it will set the read retry flag (that is |BIO_read_retry| is
413  * true). To avoid ambiguity with a normal positive return value, |eof_value|
414  * should be set to a negative value, typically -1.
415  *
416  * For a read-only BIO, the default is zero (EOF). For a writable BIO, the
417  * default is -1 so that additional data can be written once exhausted. */
418 OPENSSL_EXPORT int BIO_set_mem_eof_return(BIO *bio, int eof_value);
419 
420 
421 /* File descriptor BIOs.
422  *
423  * File descriptor BIOs are wrappers around the system's |read| and |write|
424  * functions. If the close flag is set then then |close| is called on the
425  * underlying file descriptor when the BIO is freed.
426  *
427  * |BIO_reset| attempts to seek the file pointer to the start of file using
428  * |lseek|.
429  *
430  * |BIO_seek| sets the file pointer to position |off| from start of file using
431  * |lseek|.
432  *
433  * |BIO_tell| returns the current file position. */
434 
435 /* BIO_s_fd returns a |BIO_METHOD| for file descriptor fds. */
436 OPENSSL_EXPORT const BIO_METHOD *BIO_s_fd(void);
437 
438 /* BIO_new_fd creates a new file descriptor BIO wrapping |fd|. If |close_flag|
439  * is non-zero, then |fd| will be closed when the BIO is. */
440 OPENSSL_EXPORT BIO *BIO_new_fd(int fd, int close_flag);
441 
442 /* BIO_set_fd sets the file descriptor of |bio| to |fd|. If |close_flag| is
443  * non-zero then |fd| will be closed when |bio| is. It returns one on success
444  * or zero on error. */
445 OPENSSL_EXPORT int BIO_set_fd(BIO *bio, int fd, int close_flag);
446 
447 /* BIO_get_fd returns the file descriptor currently in use by |bio| or -1 if
448  * |bio| does not wrap a file descriptor. If there is a file descriptor and
449  * |out_fd| is not NULL, it also sets |*out_fd| to the file descriptor. */
450 OPENSSL_EXPORT int BIO_get_fd(BIO *bio, int *out_fd);
451 
452 
453 /* File BIOs.
454  *
455  * File BIOs are wrappers around a C |FILE| object.
456  *
457  * |BIO_flush| on a file BIO calls |fflush| on the wrapped stream.
458  *
459  * |BIO_reset| attempts to seek the file pointer to the start of file using
460  * |fseek|.
461  *
462  * |BIO_seek| sets the file pointer to the given position from the start of
463  * file using |fseek|.
464  *
465  * |BIO_eof| calls |feof|.
466  *
467  * Setting the close flag causes |fclose| to be called on the stream when the
468  * BIO is freed. */
469 
470 /* BIO_s_file returns a BIO_METHOD that wraps a |FILE|. */
471 OPENSSL_EXPORT const BIO_METHOD *BIO_s_file(void);
472 
473 /* BIO_new_file creates a file BIO by opening |filename| with the given mode.
474  * See the |fopen| manual page for details of the mode argument. */
475 OPENSSL_EXPORT BIO *BIO_new_file(const char *filename, const char *mode);
476 
477 /* BIO_new_fp creates a new file BIO that wraps the given |FILE|. If
478  * |close_flag| is |BIO_CLOSE|, then |fclose| will be called on |stream| when
479  * the BIO is closed. */
480 OPENSSL_EXPORT BIO *BIO_new_fp(FILE *stream, int close_flag);
481 
482 /* BIO_get_fp sets |*out_file| to the current |FILE| for |bio|. It returns one
483  * on success and zero otherwise. */
484 OPENSSL_EXPORT int BIO_get_fp(BIO *bio, FILE **out_file);
485 
486 /* BIO_set_fp sets the |FILE| for |bio|. If |close_flag| is |BIO_CLOSE| then
487  * |fclose| will be called on |file| when |bio| is closed. It returns one on
488  * sucess and zero otherwise. */
489 OPENSSL_EXPORT int BIO_set_fp(BIO *bio, FILE *file, int close_flag);
490 
491 /* BIO_read_filename opens |filename| for reading and sets the result as the
492  * |FILE| for |bio|. It returns one on success and zero otherwise. The |FILE|
493  * will be closed when |bio| is freed. */
494 OPENSSL_EXPORT int BIO_read_filename(BIO *bio, const char *filename);
495 
496 /* BIO_write_filename opens |filename| for writing and sets the result as the
497  * |FILE| for |bio|. It returns one on success and zero otherwise. The |FILE|
498  * will be closed when |bio| is freed. */
499 OPENSSL_EXPORT int BIO_write_filename(BIO *bio, const char *filename);
500 
501 /* BIO_append_filename opens |filename| for appending and sets the result as
502  * the |FILE| for |bio|. It returns one on success and zero otherwise. The
503  * |FILE| will be closed when |bio| is freed. */
504 OPENSSL_EXPORT int BIO_append_filename(BIO *bio, const char *filename);
505 
506 /* BIO_rw_filename opens |filename| for reading and writing and sets the result
507  * as the |FILE| for |bio|. It returns one on success and zero otherwise. The
508  * |FILE| will be closed when |bio| is freed. */
509 OPENSSL_EXPORT int BIO_rw_filename(BIO *bio, const char *filename);
510 
511 
512 /* Buffer BIOs.
513  *
514  * Buffer BIOs are a filter-type BIO, i.e. they are designed to be used in a
515  * chain of BIOs. They provide buffering to reduce the number of operations on
516  * the underlying BIOs. */
517 
518 OPENSSL_EXPORT const BIO_METHOD *BIO_f_buffer(void);
519 
520 /* BIO_set_read_buffer_size sets the size, in bytes, of the read buffer and
521  * clears it. It returns one on success and zero on failure. */
522 OPENSSL_EXPORT int BIO_set_read_buffer_size(BIO *bio, int buffer_size);
523 
524 /* BIO_set_write_buffer_size sets the size, in bytes, of the write buffer and
525  * clears it. It returns one on success and zero on failure. */
526 OPENSSL_EXPORT int BIO_set_write_buffer_size(BIO *bio, int buffer_size);
527 
528 
529 /* Socket BIOs. */
530 
531 OPENSSL_EXPORT const BIO_METHOD *BIO_s_socket(void);
532 
533 /* BIO_new_socket allocates and initialises a fresh BIO which will read and
534  * write to the socket |fd|. If |close_flag| is |BIO_CLOSE| then closing the
535  * BIO will close |fd|. It returns the fresh |BIO| or NULL on error. */
536 OPENSSL_EXPORT BIO *BIO_new_socket(int fd, int close_flag);
537 
538 
539 /* Connect BIOs.
540  *
541  * A connection BIO creates a network connection and transfers data over the
542  * resulting socket. */
543 
544 OPENSSL_EXPORT const BIO_METHOD *BIO_s_connect(void);
545 
546 /* BIO_new_connect returns a BIO that connects to the given hostname and port.
547  * The |host_and_optional_port| argument should be of the form
548  * "www.example.com" or "www.example.com:443". If the port is omitted, it must
549  * be provided with |BIO_set_conn_port|.
550  *
551  * It returns the new BIO on success, or NULL on error. */
552 OPENSSL_EXPORT BIO *BIO_new_connect(const char *host_and_optional_port);
553 
554 /* BIO_set_conn_hostname sets |host_and_optional_port| as the hostname and
555  * optional port that |bio| will connect to. If the port is omitted, it must be
556  * provided with |BIO_set_conn_port|.
557  *
558  * It returns one on success and zero otherwise. */
559 OPENSSL_EXPORT int BIO_set_conn_hostname(BIO *bio,
560                                          const char *host_and_optional_port);
561 
562 /* BIO_set_conn_port sets |port_str| as the port or service name that |bio|
563  * will connect to. It returns one on success and zero otherwise. */
564 OPENSSL_EXPORT int BIO_set_conn_port(BIO *bio, const char *port_str);
565 
566 /* BIO_set_nbio sets whether |bio| will use non-blocking I/O operations. It
567  * returns one on success and zero otherwise. */
568 OPENSSL_EXPORT int BIO_set_nbio(BIO *bio, int on);
569 
570 
571 /* Datagram BIOs.
572  *
573  * TODO(fork): not implemented. */
574 
575 #define BIO_CTRL_DGRAM_QUERY_MTU 40 /* as kernel for current MTU */
576 
577 #define BIO_CTRL_DGRAM_SET_MTU 42 /* set cached value for  MTU. want to use
578                                      this if asking the kernel fails */
579 
580 #define BIO_CTRL_DGRAM_MTU_EXCEEDED 43 /* check whether the MTU was exceed in
581                                           the previous write operation. */
582 
583 #define BIO_CTRL_DGRAM_SET_NEXT_TIMEOUT \
584   45 /* Next DTLS handshake timeout to adjust socket timeouts */
585 
586 #define BIO_CTRL_DGRAM_GET_PEER           46
587 
588 #define BIO_CTRL_DGRAM_GET_FALLBACK_MTU   47
589 
590 
591 /* BIO Pairs.
592  *
593  * BIO pairs provide a "loopback" like system: a pair of BIOs where data
594  * written to one can be read from the other and vice versa. */
595 
596 /* BIO_new_bio_pair sets |*out1| and |*out2| to two freshly created BIOs where
597  * data written to one can be read from the other and vice versa. The
598  * |writebuf1| argument gives the size of the buffer used in |*out1| and
599  * |writebuf2| for |*out2|. It returns one on success and zero on error. */
600 OPENSSL_EXPORT int BIO_new_bio_pair(BIO **out1, size_t writebuf1, BIO **out2,
601                                     size_t writebuf2);
602 
603 /* BIO_new_bio_pair_external_buf is the same as |BIO_new_bio_pair| with the
604  * difference that the caller keeps ownership of the write buffers
605  * |ext_writebuf1_len| and |ext_writebuf2_len|. This is useful when using zero
606  * copy API for read and write operations, in cases where the buffers need to
607  * outlive the BIO pairs. It returns one on success and zero on error. */
608 OPENSSL_EXPORT int BIO_new_bio_pair_external_buf(BIO** bio1_p,
609                                                  size_t writebuf1_len,
610                                                  uint8_t* ext_writebuf1,
611                                                  BIO** bio2_p,
612                                                  size_t writebuf2_len,
613                                                  uint8_t* ext_writebuf2);
614 
615 /* BIO_ctrl_get_read_request returns the number of bytes that the other side of
616  * |bio| tried (unsuccessfully) to read. */
617 OPENSSL_EXPORT size_t BIO_ctrl_get_read_request(BIO *bio);
618 
619 /* BIO_ctrl_get_write_guarantee returns the number of bytes that |bio| (which
620  * must have been returned by |BIO_new_bio_pair|) will accept on the next
621  * |BIO_write| call. */
622 OPENSSL_EXPORT size_t BIO_ctrl_get_write_guarantee(BIO *bio);
623 
624 /* BIO_shutdown_wr marks |bio| as closed, from the point of view of the other
625  * side of the pair. Future |BIO_write| calls on |bio| will fail. It returns
626  * one on success and zero otherwise. */
627 OPENSSL_EXPORT int BIO_shutdown_wr(BIO *bio);
628 
629 
630 /* Zero copy versions of BIO_read and BIO_write for BIO pairs. */
631 
632 /* BIO_zero_copy_get_read_buf initiates a zero copy read operation.
633  * |out_read_buf| is set to the internal read buffer, and |out_buf_offset| is
634  * set to the current read position of |out_read_buf|. The number of bytes
635  * available for read from |out_read_buf| + |out_buf_offset| is returned in
636  * |out_available_bytes|. Note that this function might report fewer bytes
637  * available than |BIO_pending|, if the internal ring buffer is wrapped. It
638  * returns one on success. In case of error it returns zero and pushes to the
639  * error stack.
640  *
641  * The zero copy read operation is completed by calling
642  * |BIO_zero_copy_get_read_buf_done|. Neither |BIO_zero_copy_get_read_buf| nor
643  * any other I/O read operation may be called while a zero copy read operation
644  * is active. */
645 OPENSSL_EXPORT int BIO_zero_copy_get_read_buf(BIO* bio,
646                                               uint8_t** out_read_buf,
647                                               size_t* out_buf_offset,
648                                               size_t* out_available_bytes);
649 
650 /* BIO_zero_copy_get_read_buf_done must be called after reading from a BIO using
651  * |BIO_zero_copy_get_read_buf| to finish the read operation. The |bytes_read|
652  * argument is the number of bytes read.
653  *
654  * It returns one on success. In case of error it returns zero and pushes to the
655  * error stack. */
656 OPENSSL_EXPORT int BIO_zero_copy_get_read_buf_done(BIO* bio, size_t bytes_read);
657 
658 /* BIO_zero_copy_get_write_buf initiates a zero copy write operation.
659  * |out_write_buf| is set to to the internal write buffer, and |out_buf_offset|
660  * is set to the current write position of |out_write_buf|.
661  * The number of bytes available for write from |out_write_buf| +
662  * |out_buf_offset| is returned in |out_available_bytes|. Note that this
663  * function might report fewer bytes available than
664  * |BIO_ctrl_get_write_guarantee|, if the internal buffer is wrapped. It returns
665  * one on success. In case of error it returns zero and pushes to the error
666  * stack.
667  *
668  * The zero copy write operation is completed by calling
669  * |BIO_zero_copy_get_write_buf_done|. Neither |BIO_zero_copy_get_write_buf|
670  * nor any other I/O write operation may be called while a zero copy write
671  * operation is active. */
672 OPENSSL_EXPORT int BIO_zero_copy_get_write_buf(BIO* bio,
673                                                uint8_t** out_write_buf,
674                                                size_t* out_buf_offset,
675                                                size_t* out_available_bytes);
676 
677 /* BIO_zero_copy_get_write_buf_done must be called after writing to a BIO using
678  * |BIO_zero_copy_get_write_buf| to finish the write operation. The
679  * |bytes_written| argument gives the number of bytes written.
680  *
681  * It returns one on success. In case of error it returns zero and pushes to the
682  * error stack. */
683 OPENSSL_EXPORT int BIO_zero_copy_get_write_buf_done(BIO* bio,
684                                                     size_t bytes_written);
685 
686 
687 /* BIO_NOCLOSE and |BIO_CLOSE| can be used as symbolic arguments when a "close
688  * flag" is passed to a BIO function. */
689 #define BIO_NOCLOSE 0
690 #define BIO_CLOSE 1
691 
692 /* These are passed to the BIO callback */
693 #define BIO_CB_FREE 0x01
694 #define BIO_CB_READ 0x02
695 #define BIO_CB_WRITE 0x03
696 #define BIO_CB_PUTS 0x04
697 #define BIO_CB_GETS 0x05
698 #define BIO_CB_CTRL 0x06
699 
700 /* The callback is called before and after the underling operation,
701  * The BIO_CB_RETURN flag indicates if it is after the call */
702 #define BIO_CB_RETURN 0x80
703 
704 /* These are values of the |cmd| argument to |BIO_ctrl|. */
705 #define BIO_CTRL_RESET		1  /* opt - rewind/zero etc */
706 #define BIO_CTRL_EOF		2  /* opt - are we at the eof */
707 #define BIO_CTRL_INFO		3  /* opt - extra tit-bits */
708 #define BIO_CTRL_SET		4  /* man - set the 'IO' type */
709 #define BIO_CTRL_GET		5  /* man - get the 'IO' type */
710 #define BIO_CTRL_GET_CLOSE	8  /* man - set the 'close' on free */
711 #define BIO_CTRL_SET_CLOSE	9  /* man - set the 'close' on free */
712 #define BIO_CTRL_PENDING	10  /* opt - is their more data buffered */
713 #define BIO_CTRL_FLUSH		11  /* opt - 'flush' buffered output */
714 #define BIO_CTRL_WPENDING	13  /* opt - number of bytes still to write */
715 /* callback is int cb(BIO *bio,state,ret); */
716 #define BIO_CTRL_SET_CALLBACK	14  /* opt - set callback function */
717 #define BIO_CTRL_GET_CALLBACK	15  /* opt - set callback function */
718 #define BIO_CTRL_SET_FILENAME	30	/* BIO_s_file special */
719 
720 
721 /* Android compatibility section.
722  *
723  * A previous version of BoringSSL used in Android renamed ERR_print_errors_fp
724  * to BIO_print_errors_fp. It has subsequently been renamed back to
725  * ERR_print_errors_fp. */
726 #define BIO_print_errors_fp ERR_print_errors_fp
727 
728 
729 /* Deprecated functions. */
730 
731 /* BIO_f_base64 returns a filter |BIO| that base64-encodes data written into
732  * it, and decodes data read from it. |BIO_gets| is not supported. Call
733  * |BIO_flush| when done writing, to signal that no more data are to be
734  * encoded. The flag |BIO_FLAGS_BASE64_NO_NL| may be set to encode all the data
735  * on one line. */
736 OPENSSL_EXPORT const BIO_METHOD *BIO_f_base64(void);
737 
738 /* ERR_print_errors is an alias for |BIO_print_errors|. */
739 OPENSSL_EXPORT void ERR_print_errors(BIO *bio);
740 
741 
742 /* Private functions */
743 
744 #define BIO_FLAGS_READ 0x01
745 #define BIO_FLAGS_WRITE 0x02
746 #define BIO_FLAGS_IO_SPECIAL 0x04
747 #define BIO_FLAGS_RWS (BIO_FLAGS_READ | BIO_FLAGS_WRITE | BIO_FLAGS_IO_SPECIAL)
748 #define BIO_FLAGS_SHOULD_RETRY 0x08
749 #define BIO_FLAGS_BASE64_NO_NL 0x100
750 /* This is used with memory BIOs: it means we shouldn't free up or change the
751  * data in any way. */
752 #define BIO_FLAGS_MEM_RDONLY 0x200
753 
754 /* These are the 'types' of BIOs */
755 #define BIO_TYPE_NONE 0
756 #define BIO_TYPE_MEM (1 | 0x0400)
757 #define BIO_TYPE_FILE (2 | 0x0400)
758 #define BIO_TYPE_FD (4 | 0x0400 | 0x0100)
759 #define BIO_TYPE_SOCKET (5 | 0x0400 | 0x0100)
760 #define BIO_TYPE_NULL (6 | 0x0400)
761 #define BIO_TYPE_SSL (7 | 0x0200)
762 #define BIO_TYPE_MD (8 | 0x0200)                /* passive filter */
763 #define BIO_TYPE_BUFFER (9 | 0x0200)            /* filter */
764 #define BIO_TYPE_CIPHER (10 | 0x0200)           /* filter */
765 #define BIO_TYPE_BASE64 (11 | 0x0200)           /* filter */
766 #define BIO_TYPE_CONNECT (12 | 0x0400 | 0x0100) /* socket - connect */
767 #define BIO_TYPE_ACCEPT (13 | 0x0400 | 0x0100)  /* socket for accept */
768 #define BIO_TYPE_PROXY_CLIENT (14 | 0x0200)     /* client proxy BIO */
769 #define BIO_TYPE_PROXY_SERVER (15 | 0x0200)     /* server proxy BIO */
770 #define BIO_TYPE_NBIO_TEST (16 | 0x0200)        /* server proxy BIO */
771 #define BIO_TYPE_NULL_FILTER (17 | 0x0200)
772 #define BIO_TYPE_BER (18 | 0x0200)        /* BER -> bin filter */
773 #define BIO_TYPE_BIO (19 | 0x0400)        /* (half a) BIO pair */
774 #define BIO_TYPE_LINEBUFFER (20 | 0x0200) /* filter */
775 #define BIO_TYPE_DGRAM (21 | 0x0400 | 0x0100)
776 #define BIO_TYPE_ASN1 (22 | 0x0200) /* filter */
777 #define BIO_TYPE_COMP (23 | 0x0200) /* filter */
778 
779 #define BIO_TYPE_DESCRIPTOR 0x0100 /* socket, fd, connect or accept */
780 #define BIO_TYPE_FILTER 0x0200
781 #define BIO_TYPE_SOURCE_SINK 0x0400
782 
783 struct bio_method_st {
784   int type;
785   const char *name;
786   int (*bwrite)(BIO *, const char *, int);
787   int (*bread)(BIO *, char *, int);
788   /* TODO(fork): remove bputs. */
789   int (*bputs)(BIO *, const char *);
790   int (*bgets)(BIO *, char *, int);
791   long (*ctrl)(BIO *, int, long, void *);
792   int (*create)(BIO *);
793   int (*destroy)(BIO *);
794   long (*callback_ctrl)(BIO *, int, bio_info_cb);
795 };
796 
797 struct bio_st {
798   const BIO_METHOD *method;
799   /* bio, mode, argp, argi, argl, ret */
800   long (*callback)(BIO *, int, const char *, int, long, long);
801   char *cb_arg; /* first argument for the callback */
802 
803   /* init is non-zero if this |BIO| has been initialised. */
804   int init;
805   /* shutdown is often used by specific |BIO_METHOD|s to determine whether
806    * they own some underlying resource. This flag can often by controlled by
807    * |BIO_set_close|. For example, whether an fd BIO closes the underlying fd
808    * when it, itself, is closed. */
809   int shutdown;
810   int flags;
811   int retry_reason;
812   /* num is a BIO-specific value. For example, in fd BIOs it's used to store a
813    * file descriptor. */
814   int num;
815   CRYPTO_refcount_t references;
816   void *ptr;
817   /* next_bio points to the next |BIO| in a chain. This |BIO| owns a reference
818    * to |next_bio|. */
819   BIO *next_bio; /* used by filter BIOs */
820   size_t num_read, num_write;
821 };
822 
823 #define BIO_C_SET_CONNECT			100
824 #define BIO_C_DO_STATE_MACHINE			101
825 #define BIO_C_SET_NBIO				102
826 #define BIO_C_SET_PROXY_PARAM			103
827 #define BIO_C_SET_FD				104
828 #define BIO_C_GET_FD				105
829 #define BIO_C_SET_FILE_PTR			106
830 #define BIO_C_GET_FILE_PTR			107
831 #define BIO_C_SET_FILENAME			108
832 #define BIO_C_SET_SSL				109
833 #define BIO_C_GET_SSL				110
834 #define BIO_C_SET_MD				111
835 #define BIO_C_GET_MD				112
836 #define BIO_C_GET_CIPHER_STATUS			113
837 #define BIO_C_SET_BUF_MEM			114
838 #define BIO_C_GET_BUF_MEM_PTR			115
839 #define BIO_C_GET_BUFF_NUM_LINES		116
840 #define BIO_C_SET_BUFF_SIZE			117
841 #define BIO_C_SET_ACCEPT			118
842 #define BIO_C_SSL_MODE				119
843 #define BIO_C_GET_MD_CTX			120
844 #define BIO_C_GET_PROXY_PARAM			121
845 #define BIO_C_SET_BUFF_READ_DATA		122 /* data to read first */
846 #define BIO_C_GET_ACCEPT			124
847 #define BIO_C_SET_SSL_RENEGOTIATE_BYTES		125
848 #define BIO_C_GET_SSL_NUM_RENEGOTIATES		126
849 #define BIO_C_SET_SSL_RENEGOTIATE_TIMEOUT	127
850 #define BIO_C_FILE_SEEK				128
851 #define BIO_C_GET_CIPHER_CTX			129
852 #define BIO_C_SET_BUF_MEM_EOF_RETURN		130/*return end of input value*/
853 #define BIO_C_SET_BIND_MODE			131
854 #define BIO_C_GET_BIND_MODE			132
855 #define BIO_C_FILE_TELL				133
856 #define BIO_C_GET_SOCKS				134
857 #define BIO_C_SET_SOCKS				135
858 
859 #define BIO_C_SET_WRITE_BUF_SIZE		136/* for BIO_s_bio */
860 #define BIO_C_GET_WRITE_BUF_SIZE		137
861 #define BIO_C_GET_WRITE_GUARANTEE		140
862 #define BIO_C_GET_READ_REQUEST			141
863 #define BIO_C_SHUTDOWN_WR			142
864 #define BIO_C_NREAD0				143
865 #define BIO_C_NREAD				144
866 #define BIO_C_NWRITE0				145
867 #define BIO_C_NWRITE				146
868 #define BIO_C_RESET_READ_REQUEST		147
869 #define BIO_C_SET_MD_CTX			148
870 
871 #define BIO_C_SET_PREFIX			149
872 #define BIO_C_GET_PREFIX			150
873 #define BIO_C_SET_SUFFIX			151
874 #define BIO_C_GET_SUFFIX			152
875 
876 #define BIO_C_SET_EX_ARG			153
877 #define BIO_C_GET_EX_ARG			154
878 
879 
880 #if defined(__cplusplus)
881 }  /* extern C */
882 #endif
883 
884 #define BIO_R_BAD_FOPEN_MODE 100
885 #define BIO_R_BROKEN_PIPE 101
886 #define BIO_R_CONNECT_ERROR 102
887 #define BIO_R_ERROR_SETTING_NBIO 103
888 #define BIO_R_INVALID_ARGUMENT 104
889 #define BIO_R_IN_USE 105
890 #define BIO_R_KEEPALIVE 106
891 #define BIO_R_NBIO_CONNECT_ERROR 107
892 #define BIO_R_NO_HOSTNAME_SPECIFIED 108
893 #define BIO_R_NO_PORT_SPECIFIED 109
894 #define BIO_R_NO_SUCH_FILE 110
895 #define BIO_R_NULL_PARAMETER 111
896 #define BIO_R_SYS_LIB 112
897 #define BIO_R_UNABLE_TO_CREATE_SOCKET 113
898 #define BIO_R_UNINITIALIZED 114
899 #define BIO_R_UNSUPPORTED_METHOD 115
900 #define BIO_R_WRITE_TO_READ_ONLY_BIO 116
901 
902 #endif  /* OPENSSL_HEADER_BIO_H */
903