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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/buffer.h>
65 #include <openssl/err.h> /* for ERR_print_errors_fp */
66 #include <openssl/ex_data.h>
67 #include <openssl/stack.h>
68 #include <openssl/thread.h>
69 
70 #if defined(__cplusplus)
71 extern "C" {
72 #endif
73 
74 
75 /* BIO abstracts over a file-descriptor like interface. */
76 
77 
78 /* Allocation and freeing. */
79 
80 DEFINE_STACK_OF(BIO)
81 
82 /* BIO_new creates a new BIO with the given type and a reference count of one.
83  * It returns the fresh |BIO|, or NULL on error. */
84 OPENSSL_EXPORT BIO *BIO_new(const BIO_METHOD *type);
85 
86 /* BIO_free decrements the reference count of |bio|. If the reference count
87  * drops to zero, it (optionally) calls the BIO's callback with |BIO_CB_FREE|,
88  * frees the ex_data and then, if the BIO has a destroy callback for the
89  * method, calls it. Finally it frees |bio| itself. It then repeats that for
90  * the next BIO in the chain, if any.
91  *
92  * It returns one on success or zero otherwise. */
93 OPENSSL_EXPORT int BIO_free(BIO *bio);
94 
95 /* BIO_vfree performs the same actions as |BIO_free|, but has a void return
96  * value. This is provided for API-compat.
97  *
98  * TODO(fork): remove. */
99 OPENSSL_EXPORT void BIO_vfree(BIO *bio);
100 
101 /* BIO_up_ref increments the reference count of |bio| and returns one. */
102 OPENSSL_EXPORT int BIO_up_ref(BIO *bio);
103 
104 
105 /* Basic I/O. */
106 
107 /* BIO_read attempts to read |len| bytes into |data|. It returns the number of
108  * bytes read, zero on EOF, or a negative number on error. */
109 OPENSSL_EXPORT int BIO_read(BIO *bio, void *data, int len);
110 
111 /* BIO_gets "reads a line" from |bio| and puts at most |size| bytes into |buf|.
112  * It returns the number of bytes read or a negative number on error. The
113  * phrase "reads a line" is in quotes in the previous sentence because the
114  * exact operation depends on the BIO's method. For example, a digest BIO will
115  * return the digest in response to a |BIO_gets| call.
116  *
117  * TODO(fork): audit the set of BIOs that we end up needing. If all actually
118  * return a line for this call, remove the warning above. */
119 OPENSSL_EXPORT int BIO_gets(BIO *bio, char *buf, int size);
120 
121 /* BIO_write writes |len| bytes from |data| to BIO. It returns the number of
122  * bytes written or a negative number on error. */
123 OPENSSL_EXPORT int BIO_write(BIO *bio, const void *data, int len);
124 
125 /* BIO_puts writes a NUL terminated string from |buf| to |bio|. It returns the
126  * number of bytes written or a negative number on error. */
127 OPENSSL_EXPORT int BIO_puts(BIO *bio, const char *buf);
128 
129 /* BIO_flush flushes any buffered output. It returns one on success and zero
130  * otherwise. */
131 OPENSSL_EXPORT int BIO_flush(BIO *bio);
132 
133 
134 /* Low-level control functions.
135  *
136  * These are generic functions for sending control requests to a BIO. In
137  * general one should use the wrapper functions like |BIO_get_close|. */
138 
139 /* BIO_ctrl sends the control request |cmd| to |bio|. The |cmd| argument should
140  * be one of the |BIO_C_*| values. */
141 OPENSSL_EXPORT long BIO_ctrl(BIO *bio, int cmd, long larg, void *parg);
142 
143 /* BIO_ptr_ctrl acts like |BIO_ctrl| but passes the address of a |void*|
144  * pointer as |parg| and returns the value that is written to it, or NULL if
145  * the control request returns <= 0. */
146 OPENSSL_EXPORT char *BIO_ptr_ctrl(BIO *bp, int cmd, long larg);
147 
148 /* BIO_int_ctrl acts like |BIO_ctrl| but passes the address of a copy of |iarg|
149  * as |parg|. */
150 OPENSSL_EXPORT long BIO_int_ctrl(BIO *bp, int cmd, long larg, int iarg);
151 
152 /* BIO_reset resets |bio| to its initial state, the precise meaning of which
153  * depends on the concrete type of |bio|. It returns one on success and zero
154  * otherwise. */
155 OPENSSL_EXPORT int BIO_reset(BIO *bio);
156 
157 /* BIO_eof returns non-zero when |bio| has reached end-of-file. The precise
158  * meaning of which depends on the concrete type of |bio|. Note that in the
159  * case of BIO_pair this always returns non-zero. */
160 OPENSSL_EXPORT int BIO_eof(BIO *bio);
161 
162 /* BIO_set_flags ORs |flags| with |bio->flags|. */
163 OPENSSL_EXPORT void BIO_set_flags(BIO *bio, int flags);
164 
165 /* BIO_test_flags returns |bio->flags| AND |flags|. */
166 OPENSSL_EXPORT int BIO_test_flags(const BIO *bio, int flags);
167 
168 /* BIO_should_read returns non-zero if |bio| encountered a temporary error
169  * while reading (i.e. EAGAIN), indicating that the caller should retry the
170  * read. */
171 OPENSSL_EXPORT int BIO_should_read(const BIO *bio);
172 
173 /* BIO_should_write returns non-zero if |bio| encountered a temporary error
174  * while writing (i.e. EAGAIN), indicating that the caller should retry the
175  * write. */
176 OPENSSL_EXPORT int BIO_should_write(const BIO *bio);
177 
178 /* BIO_should_retry returns non-zero if the reason that caused a failed I/O
179  * operation is temporary and thus the operation should be retried. Otherwise,
180  * it was a permanent error and it returns zero. */
181 OPENSSL_EXPORT int BIO_should_retry(const BIO *bio);
182 
183 /* BIO_should_io_special returns non-zero if |bio| encountered a temporary
184  * error while performing a special I/O operation, indicating that the caller
185  * should retry. The operation that caused the error is returned by
186  * |BIO_get_retry_reason|. */
187 OPENSSL_EXPORT int BIO_should_io_special(const BIO *bio);
188 
189 /* BIO_RR_CONNECT indicates that a connect would have blocked */
190 #define BIO_RR_CONNECT 0x02
191 
192 /* BIO_RR_ACCEPT indicates that an accept would have blocked */
193 #define BIO_RR_ACCEPT 0x03
194 
195 /* BIO_get_retry_reason returns the special I/O operation that needs to be
196  * retried. The return value is one of the |BIO_RR_*| values. */
197 OPENSSL_EXPORT int BIO_get_retry_reason(const BIO *bio);
198 
199 /* BIO_clear_flags ANDs |bio->flags| with the bitwise-complement of |flags|. */
200 OPENSSL_EXPORT void BIO_clear_flags(BIO *bio, int flags);
201 
202 /* BIO_set_retry_read sets the |BIO_FLAGS_READ| and |BIO_FLAGS_SHOULD_RETRY|
203  * flags on |bio|. */
204 OPENSSL_EXPORT void BIO_set_retry_read(BIO *bio);
205 
206 /* BIO_set_retry_write sets the |BIO_FLAGS_WRITE| and |BIO_FLAGS_SHOULD_RETRY|
207  * flags on |bio|. */
208 OPENSSL_EXPORT void BIO_set_retry_write(BIO *bio);
209 
210 /* BIO_get_retry_flags gets the |BIO_FLAGS_READ|, |BIO_FLAGS_WRITE|,
211  * |BIO_FLAGS_IO_SPECIAL| and |BIO_FLAGS_SHOULD_RETRY| flags from |bio|. */
212 OPENSSL_EXPORT int BIO_get_retry_flags(BIO *bio);
213 
214 /* BIO_clear_retry_flags clears the |BIO_FLAGS_READ|, |BIO_FLAGS_WRITE|,
215  * |BIO_FLAGS_IO_SPECIAL| and |BIO_FLAGS_SHOULD_RETRY| flags from |bio|. */
216 OPENSSL_EXPORT void BIO_clear_retry_flags(BIO *bio);
217 
218 /* BIO_method_type returns the type of |bio|, which is one of the |BIO_TYPE_*|
219  * values. */
220 OPENSSL_EXPORT int BIO_method_type(const BIO *bio);
221 
222 /* bio_info_cb is the type of a callback function that can be called for most
223  * BIO operations. The |event| argument is one of |BIO_CB_*| and can be ORed
224  * with |BIO_CB_RETURN| if the callback is being made after the operation in
225  * question. In that case, |return_value| will contain the return value from
226  * the operation. */
227 typedef long (*bio_info_cb)(BIO *bio, int event, const char *parg, int cmd,
228                             long larg, long return_value);
229 
230 /* BIO_callback_ctrl allows the callback function to be manipulated. The |cmd|
231  * arg will generally be |BIO_CTRL_SET_CALLBACK| but arbitrary command values
232  * can be interpreted by the |BIO|. */
233 OPENSSL_EXPORT long BIO_callback_ctrl(BIO *bio, int cmd, bio_info_cb fp);
234 
235 /* BIO_pending returns the number of bytes pending to be read. */
236 OPENSSL_EXPORT size_t BIO_pending(const BIO *bio);
237 
238 /* BIO_ctrl_pending calls |BIO_pending| and exists only for compatibility with
239  * OpenSSL. */
240 OPENSSL_EXPORT size_t BIO_ctrl_pending(const BIO *bio);
241 
242 /* BIO_wpending returns the number of bytes pending to be written. */
243 OPENSSL_EXPORT size_t BIO_wpending(const BIO *bio);
244 
245 /* BIO_set_close sets the close flag for |bio|. The meaning of which depends on
246  * the type of |bio| but, for example, a memory BIO interprets the close flag
247  * as meaning that it owns its buffer. It returns one on success and zero
248  * otherwise. */
249 OPENSSL_EXPORT int BIO_set_close(BIO *bio, int close_flag);
250 
251 /* BIO_set_callback sets a callback function that will be called before and
252  * after most operations. See the comment above |bio_info_cb|. */
253 OPENSSL_EXPORT void BIO_set_callback(BIO *bio, bio_info_cb callback_func);
254 
255 /* BIO_set_callback_arg sets the opaque pointer value that can be read within a
256  * callback with |BIO_get_callback_arg|. */
257 OPENSSL_EXPORT void BIO_set_callback_arg(BIO *bio, char *arg);
258 
259 /* BIO_get_callback_arg returns the last value of the opaque callback pointer
260  * set by |BIO_set_callback_arg|. */
261 OPENSSL_EXPORT char *BIO_get_callback_arg(const BIO *bio);
262 
263 /* BIO_number_read returns the number of bytes that have been read from
264  * |bio|. */
265 OPENSSL_EXPORT size_t BIO_number_read(const BIO *bio);
266 
267 /* BIO_number_written returns the number of bytes that have been written to
268  * |bio|. */
269 OPENSSL_EXPORT size_t BIO_number_written(const BIO *bio);
270 
271 
272 /* Managing chains of BIOs.
273  *
274  * BIOs can be put into chains where the output of one is used as the input of
275  * the next etc. The most common case is a buffering BIO, which accepts and
276  * buffers writes until flushed into the next BIO in the chain. */
277 
278 /* BIO_push adds |appended_bio| to the end of the chain with |bio| at the head.
279  * It returns |bio|. Note that |appended_bio| may be the head of a chain itself
280  * and thus this function can be used to join two chains.
281  *
282  * BIO_push takes ownership of the caller's reference to |appended_bio|. */
283 OPENSSL_EXPORT BIO *BIO_push(BIO *bio, BIO *appended_bio);
284 
285 /* BIO_pop removes |bio| from the head of a chain and returns the next BIO in
286  * the chain, or NULL if there is no next BIO.
287  *
288  * The caller takes ownership of the chain's reference to |bio|. */
289 OPENSSL_EXPORT BIO *BIO_pop(BIO *bio);
290 
291 /* BIO_next returns the next BIO in the chain after |bio|, or NULL if there is
292  * no such BIO. */
293 OPENSSL_EXPORT BIO *BIO_next(BIO *bio);
294 
295 /* BIO_free_all calls |BIO_free|.
296  *
297  * TODO(fork): update callers and remove. */
298 OPENSSL_EXPORT void BIO_free_all(BIO *bio);
299 
300 /* BIO_find_type walks a chain of BIOs and returns the first that matches
301  * |type|, which is one of the |BIO_TYPE_*| values. */
302 OPENSSL_EXPORT BIO *BIO_find_type(BIO *bio, int type);
303 
304 /* BIO_copy_next_retry sets the retry flags and |retry_reason| of |bio| from
305  * the next BIO in the chain. */
306 OPENSSL_EXPORT void BIO_copy_next_retry(BIO *bio);
307 
308 
309 /* Printf functions. */
310 
311 /* BIO_printf behaves like |printf| but outputs to |bio| rather than a |FILE|.
312  * It returns the number of bytes written or a negative number on error. */
313 OPENSSL_EXPORT int BIO_printf(BIO *bio, const char *format, ...)
314     OPENSSL_PRINTF_FORMAT_FUNC(2, 3);
315 
316 
317 /* Utility functions. */
318 
319 /* BIO_indent prints min(|indent|, |max_indent|) spaces. It returns one on
320  * success and zero otherwise. */
321 OPENSSL_EXPORT int BIO_indent(BIO *bio, unsigned indent, unsigned max_indent);
322 
323 /* BIO_hexdump writes a hex dump of |data| to |bio|. Each line will be indented
324  * by |indent| spaces. */
325 OPENSSL_EXPORT int BIO_hexdump(BIO *bio, const uint8_t *data, size_t len,
326                                unsigned indent);
327 
328 /* ERR_print_errors prints the current contents of the error stack to |bio|
329  * using human readable strings where possible. */
330 OPENSSL_EXPORT void ERR_print_errors(BIO *bio);
331 
332 /* BIO_read_asn1 reads a single ASN.1 object from |bio|. If successful it sets
333  * |*out| to be an allocated buffer (that should be freed with |OPENSSL_free|),
334  * |*out_size| to the length, in bytes, of that buffer and returns one.
335  * Otherwise it returns zero.
336  *
337  * If the length of the object is greater than |max_len| or 2^32 then the
338  * function will fail. Long-form tags are not supported. If the length of the
339  * object is indefinite the full contents of |bio| are read, unless it would be
340  * greater than |max_len|, in which case the function fails.
341  *
342  * If the function fails then some unknown amount of data may have been read
343  * from |bio|. */
344 OPENSSL_EXPORT int BIO_read_asn1(BIO *bio, uint8_t **out, size_t *out_len,
345                                  size_t max_len);
346 
347 
348 /* Memory BIOs.
349  *
350  * Memory BIOs can be used as a read-only source (with |BIO_new_mem_buf|) or a
351  * writable sink (with |BIO_new|, |BIO_s_mem| and |BIO_get_mem_buf|). Data
352  * written to a writable, memory BIO can be recalled by reading from it.
353  *
354  * Calling |BIO_reset| on a read-only BIO resets it to the original contents.
355  * On a writable BIO, it clears any data.
356  *
357  * If the close flag is set to |BIO_NOCLOSE| (not the default) then the
358  * underlying |BUF_MEM| will not be freed when the |BIO| is freed.
359  *
360  * Memory BIOs support |BIO_gets| and |BIO_puts|.
361  *
362  * |BIO_ctrl_pending| returns the number of bytes currently stored. */
363 
364 /* BIO_s_mem returns a |BIO_METHOD| that uses a in-memory buffer. */
365 OPENSSL_EXPORT const BIO_METHOD *BIO_s_mem(void);
366 
367 /* BIO_new_mem_buf creates read-only BIO that reads from |len| bytes at |buf|.
368  * It does not take ownership of |buf|. It returns the BIO or NULL on error.
369  *
370  * If |len| is negative, then |buf| is treated as a NUL-terminated string, but
371  * don't depend on this in new code. */
372 OPENSSL_EXPORT BIO *BIO_new_mem_buf(const void *buf, int len);
373 
374 /* BIO_mem_contents sets |*out_contents| to point to the current contents of
375  * |bio| and |*out_len| to contain the length of that data. It returns one on
376  * success and zero otherwise. */
377 OPENSSL_EXPORT int BIO_mem_contents(const BIO *bio,
378                                     const uint8_t **out_contents,
379                                     size_t *out_len);
380 
381 /* BIO_get_mem_data sets |*contents| to point to the current contents of |bio|
382  * and returns the length of the data.
383  *
384  * WARNING: don't use this, use |BIO_mem_contents|. A return value of zero from
385  * this function can mean either that it failed or that the memory buffer is
386  * empty. */
387 OPENSSL_EXPORT long BIO_get_mem_data(BIO *bio, char **contents);
388 
389 /* BIO_get_mem_ptr sets |*out| to a BUF_MEM containing the current contents of
390  * |bio|. It returns one on success or zero on error. */
391 OPENSSL_EXPORT int BIO_get_mem_ptr(BIO *bio, BUF_MEM **out);
392 
393 /* BIO_set_mem_buf sets |b| as the contents of |bio|. If |take_ownership| is
394  * non-zero, then |b| will be freed when |bio| is closed. Returns one on
395  * success or zero otherwise. */
396 OPENSSL_EXPORT int BIO_set_mem_buf(BIO *bio, BUF_MEM *b, int take_ownership);
397 
398 /* BIO_set_mem_eof_return sets the value that will be returned from reading
399  * |bio| when empty. If |eof_value| is zero then an empty memory BIO will
400  * return EOF (that is it will return zero and |BIO_should_retry| will be
401  * false). If |eof_value| is non zero then it will return |eof_value| when it
402  * is empty and it will set the read retry flag (that is |BIO_read_retry| is
403  * true). To avoid ambiguity with a normal positive return value, |eof_value|
404  * should be set to a negative value, typically -1.
405  *
406  * For a read-only BIO, the default is zero (EOF). For a writable BIO, the
407  * default is -1 so that additional data can be written once exhausted. */
408 OPENSSL_EXPORT int BIO_set_mem_eof_return(BIO *bio, int eof_value);
409 
410 
411 /* File descriptor BIOs.
412  *
413  * File descriptor BIOs are wrappers around the system's |read| and |write|
414  * functions. If the close flag is set then then |close| is called on the
415  * underlying file descriptor when the BIO is freed.
416  *
417  * |BIO_reset| attempts to seek the file pointer to the start of file using
418  * |lseek|. */
419 
420 /* BIO_s_fd returns a |BIO_METHOD| for file descriptor fds. */
421 OPENSSL_EXPORT const BIO_METHOD *BIO_s_fd(void);
422 
423 /* BIO_new_fd creates a new file descriptor BIO wrapping |fd|. If |close_flag|
424  * is non-zero, then |fd| will be closed when the BIO is. */
425 OPENSSL_EXPORT BIO *BIO_new_fd(int fd, int close_flag);
426 
427 /* BIO_set_fd sets the file descriptor of |bio| to |fd|. If |close_flag| is
428  * non-zero then |fd| will be closed when |bio| is. It returns one on success
429  * or zero on error.
430  *
431  * This function may also be used with socket BIOs (see |BIO_s_socket| and
432  * |BIO_new_socket|). */
433 OPENSSL_EXPORT int BIO_set_fd(BIO *bio, int fd, int close_flag);
434 
435 /* BIO_get_fd returns the file descriptor currently in use by |bio| or -1 if
436  * |bio| does not wrap a file descriptor. If there is a file descriptor and
437  * |out_fd| is not NULL, it also sets |*out_fd| to the file descriptor.
438  *
439  * This function may also be used with socket BIOs (see |BIO_s_socket| and
440  * |BIO_new_socket|). */
441 OPENSSL_EXPORT int BIO_get_fd(BIO *bio, int *out_fd);
442 
443 
444 /* File BIOs.
445  *
446  * File BIOs are wrappers around a C |FILE| object.
447  *
448  * |BIO_flush| on a file BIO calls |fflush| on the wrapped stream.
449  *
450  * |BIO_reset| attempts to seek the file pointer to the start of file using
451  * |fseek|.
452  *
453  * Setting the close flag causes |fclose| to be called on the stream when the
454  * BIO is freed. */
455 
456 /* BIO_s_file returns a BIO_METHOD that wraps a |FILE|. */
457 OPENSSL_EXPORT const BIO_METHOD *BIO_s_file(void);
458 
459 /* BIO_new_file creates a file BIO by opening |filename| with the given mode.
460  * See the |fopen| manual page for details of the mode argument. */
461 OPENSSL_EXPORT BIO *BIO_new_file(const char *filename, const char *mode);
462 
463 /* BIO_new_fp creates a new file BIO that wraps the given |FILE|. If
464  * |close_flag| is |BIO_CLOSE|, then |fclose| will be called on |stream| when
465  * the BIO is closed. */
466 OPENSSL_EXPORT BIO *BIO_new_fp(FILE *stream, int close_flag);
467 
468 /* BIO_get_fp sets |*out_file| to the current |FILE| for |bio|. It returns one
469  * on success and zero otherwise. */
470 OPENSSL_EXPORT int BIO_get_fp(BIO *bio, FILE **out_file);
471 
472 /* BIO_set_fp sets the |FILE| for |bio|. If |close_flag| is |BIO_CLOSE| then
473  * |fclose| will be called on |file| when |bio| is closed. It returns one on
474  * success and zero otherwise. */
475 OPENSSL_EXPORT int BIO_set_fp(BIO *bio, FILE *file, int close_flag);
476 
477 /* BIO_read_filename opens |filename| for reading and sets the result as the
478  * |FILE| for |bio|. It returns one on success and zero otherwise. The |FILE|
479  * will be closed when |bio| is freed. */
480 OPENSSL_EXPORT int BIO_read_filename(BIO *bio, const char *filename);
481 
482 /* BIO_write_filename opens |filename| for writing and sets the result as the
483  * |FILE| for |bio|. It returns one on success and zero otherwise. The |FILE|
484  * will be closed when |bio| is freed. */
485 OPENSSL_EXPORT int BIO_write_filename(BIO *bio, const char *filename);
486 
487 /* BIO_append_filename opens |filename| for appending and sets the result as
488  * the |FILE| for |bio|. It returns one on success and zero otherwise. The
489  * |FILE| will be closed when |bio| is freed. */
490 OPENSSL_EXPORT int BIO_append_filename(BIO *bio, const char *filename);
491 
492 /* BIO_rw_filename opens |filename| for reading and writing and sets the result
493  * as the |FILE| for |bio|. It returns one on success and zero otherwise. The
494  * |FILE| will be closed when |bio| is freed. */
495 OPENSSL_EXPORT int BIO_rw_filename(BIO *bio, const char *filename);
496 
497 
498 /* Socket BIOs.
499  *
500  * Socket BIOs behave like file descriptor BIOs but, on Windows systems, wrap
501  * the system's |recv| and |send| functions instead of |read| and |write|. On
502  * Windows, file descriptors are provided by C runtime and are not
503  * interchangeable with sockets.
504  *
505  * Socket BIOs may be used with |BIO_set_fd| and |BIO_get_fd|.
506  *
507  * TODO(davidben): Add separate APIs and fix the internals to use |SOCKET|s
508  * around rather than rely on int casts. */
509 
510 OPENSSL_EXPORT const BIO_METHOD *BIO_s_socket(void);
511 
512 /* BIO_new_socket allocates and initialises a fresh BIO which will read and
513  * write to the socket |fd|. If |close_flag| is |BIO_CLOSE| then closing the
514  * BIO will close |fd|. It returns the fresh |BIO| or NULL on error. */
515 OPENSSL_EXPORT BIO *BIO_new_socket(int fd, int close_flag);
516 
517 
518 /* Connect BIOs.
519  *
520  * A connection BIO creates a network connection and transfers data over the
521  * resulting socket. */
522 
523 OPENSSL_EXPORT const BIO_METHOD *BIO_s_connect(void);
524 
525 /* BIO_new_connect returns a BIO that connects to the given hostname and port.
526  * The |host_and_optional_port| argument should be of the form
527  * "www.example.com" or "www.example.com:443". If the port is omitted, it must
528  * be provided with |BIO_set_conn_port|.
529  *
530  * It returns the new BIO on success, or NULL on error. */
531 OPENSSL_EXPORT BIO *BIO_new_connect(const char *host_and_optional_port);
532 
533 /* BIO_set_conn_hostname sets |host_and_optional_port| as the hostname and
534  * optional port that |bio| will connect to. If the port is omitted, it must be
535  * provided with |BIO_set_conn_port|.
536  *
537  * It returns one on success and zero otherwise. */
538 OPENSSL_EXPORT int BIO_set_conn_hostname(BIO *bio,
539                                          const char *host_and_optional_port);
540 
541 /* BIO_set_conn_port sets |port_str| as the port or service name that |bio|
542  * will connect to. It returns one on success and zero otherwise. */
543 OPENSSL_EXPORT int BIO_set_conn_port(BIO *bio, const char *port_str);
544 
545 /* BIO_set_conn_int_port sets |*port| as the port that |bio| will connect to.
546  * It returns one on success and zero otherwise. */
547 OPENSSL_EXPORT int BIO_set_conn_int_port(BIO *bio, const int *port);
548 
549 /* BIO_set_nbio sets whether |bio| will use non-blocking I/O operations. It
550  * returns one on success and zero otherwise. */
551 OPENSSL_EXPORT int BIO_set_nbio(BIO *bio, int on);
552 
553 /* BIO_do_connect connects |bio| if it has not been connected yet. It returns
554  * one on success and <= 0 otherwise. */
555 OPENSSL_EXPORT int BIO_do_connect(BIO *bio);
556 
557 
558 /* Datagram BIOs.
559  *
560  * TODO(fork): not implemented. */
561 
562 #define BIO_CTRL_DGRAM_QUERY_MTU 40 /* as kernel for current MTU */
563 
564 #define BIO_CTRL_DGRAM_SET_MTU 42 /* set cached value for  MTU. want to use
565                                      this if asking the kernel fails */
566 
567 #define BIO_CTRL_DGRAM_MTU_EXCEEDED 43 /* check whether the MTU was exceed in
568                                           the previous write operation. */
569 
570 /* BIO_CTRL_DGRAM_SET_NEXT_TIMEOUT is unsupported as it is unused by consumers
571  * and depends on |timeval|, which is not 2038-clean on all platforms. */
572 
573 #define BIO_CTRL_DGRAM_GET_PEER           46
574 
575 #define BIO_CTRL_DGRAM_GET_FALLBACK_MTU   47
576 
577 
578 /* BIO Pairs.
579  *
580  * BIO pairs provide a "loopback" like system: a pair of BIOs where data
581  * written to one can be read from the other and vice versa. */
582 
583 /* BIO_new_bio_pair sets |*out1| and |*out2| to two freshly created BIOs where
584  * data written to one can be read from the other and vice versa. The
585  * |writebuf1| argument gives the size of the buffer used in |*out1| and
586  * |writebuf2| for |*out2|. It returns one on success and zero on error. */
587 OPENSSL_EXPORT int BIO_new_bio_pair(BIO **out1, size_t writebuf1, BIO **out2,
588                                     size_t writebuf2);
589 
590 /* BIO_ctrl_get_read_request returns the number of bytes that the other side of
591  * |bio| tried (unsuccessfully) to read. */
592 OPENSSL_EXPORT size_t BIO_ctrl_get_read_request(BIO *bio);
593 
594 /* BIO_ctrl_get_write_guarantee returns the number of bytes that |bio| (which
595  * must have been returned by |BIO_new_bio_pair|) will accept on the next
596  * |BIO_write| call. */
597 OPENSSL_EXPORT size_t BIO_ctrl_get_write_guarantee(BIO *bio);
598 
599 /* BIO_shutdown_wr marks |bio| as closed, from the point of view of the other
600  * side of the pair. Future |BIO_write| calls on |bio| will fail. It returns
601  * one on success and zero otherwise. */
602 OPENSSL_EXPORT int BIO_shutdown_wr(BIO *bio);
603 
604 
605 /* BIO_NOCLOSE and |BIO_CLOSE| can be used as symbolic arguments when a "close
606  * flag" is passed to a BIO function. */
607 #define BIO_NOCLOSE 0
608 #define BIO_CLOSE 1
609 
610 /* These are passed to the BIO callback */
611 #define BIO_CB_FREE 0x01
612 #define BIO_CB_READ 0x02
613 #define BIO_CB_WRITE 0x03
614 #define BIO_CB_PUTS 0x04
615 #define BIO_CB_GETS 0x05
616 #define BIO_CB_CTRL 0x06
617 
618 /* The callback is called before and after the underling operation,
619  * The BIO_CB_RETURN flag indicates if it is after the call */
620 #define BIO_CB_RETURN 0x80
621 
622 /* These are values of the |cmd| argument to |BIO_ctrl|. */
623 #define BIO_CTRL_RESET		1  /* opt - rewind/zero etc */
624 #define BIO_CTRL_EOF		2  /* opt - are we at the eof */
625 #define BIO_CTRL_INFO		3  /* opt - extra tit-bits */
626 #define BIO_CTRL_SET		4  /* man - set the 'IO' type */
627 #define BIO_CTRL_GET		5  /* man - get the 'IO' type */
628 #define BIO_CTRL_PUSH	6
629 #define BIO_CTRL_POP	7
630 #define BIO_CTRL_GET_CLOSE	8  /* man - set the 'close' on free */
631 #define BIO_CTRL_SET_CLOSE	9  /* man - set the 'close' on free */
632 #define BIO_CTRL_PENDING	10  /* opt - is their more data buffered */
633 #define BIO_CTRL_FLUSH		11  /* opt - 'flush' buffered output */
634 #define BIO_CTRL_WPENDING	13  /* opt - number of bytes still to write */
635 /* callback is int cb(BIO *bio,state,ret); */
636 #define BIO_CTRL_SET_CALLBACK	14  /* opt - set callback function */
637 #define BIO_CTRL_GET_CALLBACK	15  /* opt - set callback function */
638 #define BIO_CTRL_SET_FILENAME	30	/* BIO_s_file special */
639 
640 /* BIO_CTRL_DUP is never used, but exists to allow code to compile more
641  * easily. */
642 #define BIO_CTRL_DUP	12
643 
644 
645 /* Deprecated functions. */
646 
647 /* BIO_f_base64 returns a filter |BIO| that base64-encodes data written into
648  * it, and decodes data read from it. |BIO_gets| is not supported. Call
649  * |BIO_flush| when done writing, to signal that no more data are to be
650  * encoded. The flag |BIO_FLAGS_BASE64_NO_NL| may be set to encode all the data
651  * on one line. */
652 OPENSSL_EXPORT const BIO_METHOD *BIO_f_base64(void);
653 
654 OPENSSL_EXPORT void BIO_set_retry_special(BIO *bio);
655 
656 /* BIO_set_write_buffer_size returns zero. */
657 OPENSSL_EXPORT int BIO_set_write_buffer_size(BIO *bio, int buffer_size);
658 
659 
660 /* Private functions */
661 
662 #define BIO_FLAGS_READ 0x01
663 #define BIO_FLAGS_WRITE 0x02
664 #define BIO_FLAGS_IO_SPECIAL 0x04
665 #define BIO_FLAGS_RWS (BIO_FLAGS_READ | BIO_FLAGS_WRITE | BIO_FLAGS_IO_SPECIAL)
666 #define BIO_FLAGS_SHOULD_RETRY 0x08
667 #define BIO_FLAGS_BASE64_NO_NL 0x100
668 /* This is used with memory BIOs: it means we shouldn't free up or change the
669  * data in any way. */
670 #define BIO_FLAGS_MEM_RDONLY 0x200
671 
672 /* These are the 'types' of BIOs */
673 #define BIO_TYPE_NONE 0
674 #define BIO_TYPE_MEM (1 | 0x0400)
675 #define BIO_TYPE_FILE (2 | 0x0400)
676 #define BIO_TYPE_FD (4 | 0x0400 | 0x0100)
677 #define BIO_TYPE_SOCKET (5 | 0x0400 | 0x0100)
678 #define BIO_TYPE_NULL (6 | 0x0400)
679 #define BIO_TYPE_SSL (7 | 0x0200)
680 #define BIO_TYPE_MD (8 | 0x0200)                /* passive filter */
681 #define BIO_TYPE_BUFFER (9 | 0x0200)            /* filter */
682 #define BIO_TYPE_CIPHER (10 | 0x0200)           /* filter */
683 #define BIO_TYPE_BASE64 (11 | 0x0200)           /* filter */
684 #define BIO_TYPE_CONNECT (12 | 0x0400 | 0x0100) /* socket - connect */
685 #define BIO_TYPE_ACCEPT (13 | 0x0400 | 0x0100)  /* socket for accept */
686 #define BIO_TYPE_PROXY_CLIENT (14 | 0x0200)     /* client proxy BIO */
687 #define BIO_TYPE_PROXY_SERVER (15 | 0x0200)     /* server proxy BIO */
688 #define BIO_TYPE_NBIO_TEST (16 | 0x0200)        /* server proxy BIO */
689 #define BIO_TYPE_NULL_FILTER (17 | 0x0200)
690 #define BIO_TYPE_BER (18 | 0x0200)        /* BER -> bin filter */
691 #define BIO_TYPE_BIO (19 | 0x0400)        /* (half a) BIO pair */
692 #define BIO_TYPE_LINEBUFFER (20 | 0x0200) /* filter */
693 #define BIO_TYPE_DGRAM (21 | 0x0400 | 0x0100)
694 #define BIO_TYPE_ASN1 (22 | 0x0200) /* filter */
695 #define BIO_TYPE_COMP (23 | 0x0200) /* filter */
696 
697 #define BIO_TYPE_DESCRIPTOR 0x0100 /* socket, fd, connect or accept */
698 #define BIO_TYPE_FILTER 0x0200
699 #define BIO_TYPE_SOURCE_SINK 0x0400
700 
701 struct bio_method_st {
702   int type;
703   const char *name;
704   int (*bwrite)(BIO *, const char *, int);
705   int (*bread)(BIO *, char *, int);
706   /* TODO(fork): remove bputs. */
707   int (*bputs)(BIO *, const char *);
708   int (*bgets)(BIO *, char *, int);
709   long (*ctrl)(BIO *, int, long, void *);
710   int (*create)(BIO *);
711   int (*destroy)(BIO *);
712   long (*callback_ctrl)(BIO *, int, bio_info_cb);
713 };
714 
715 struct bio_st {
716   const BIO_METHOD *method;
717   /* bio, mode, argp, argi, argl, ret */
718   long (*callback)(BIO *, int, const char *, int, long, long);
719   char *cb_arg; /* first argument for the callback */
720 
721   /* init is non-zero if this |BIO| has been initialised. */
722   int init;
723   /* shutdown is often used by specific |BIO_METHOD|s to determine whether
724    * they own some underlying resource. This flag can often by controlled by
725    * |BIO_set_close|. For example, whether an fd BIO closes the underlying fd
726    * when it, itself, is closed. */
727   int shutdown;
728   int flags;
729   int retry_reason;
730   /* num is a BIO-specific value. For example, in fd BIOs it's used to store a
731    * file descriptor. */
732   int num;
733   CRYPTO_refcount_t references;
734   void *ptr;
735   /* next_bio points to the next |BIO| in a chain. This |BIO| owns a reference
736    * to |next_bio|. */
737   BIO *next_bio; /* used by filter BIOs */
738   size_t num_read, num_write;
739 };
740 
741 #define BIO_C_SET_CONNECT			100
742 #define BIO_C_DO_STATE_MACHINE			101
743 #define BIO_C_SET_NBIO				102
744 #define BIO_C_SET_PROXY_PARAM			103
745 #define BIO_C_SET_FD				104
746 #define BIO_C_GET_FD				105
747 #define BIO_C_SET_FILE_PTR			106
748 #define BIO_C_GET_FILE_PTR			107
749 #define BIO_C_SET_FILENAME			108
750 #define BIO_C_SET_SSL				109
751 #define BIO_C_GET_SSL				110
752 #define BIO_C_SET_MD				111
753 #define BIO_C_GET_MD				112
754 #define BIO_C_GET_CIPHER_STATUS			113
755 #define BIO_C_SET_BUF_MEM			114
756 #define BIO_C_GET_BUF_MEM_PTR			115
757 #define BIO_C_GET_BUFF_NUM_LINES		116
758 #define BIO_C_SET_BUFF_SIZE			117
759 #define BIO_C_SET_ACCEPT			118
760 #define BIO_C_SSL_MODE				119
761 #define BIO_C_GET_MD_CTX			120
762 #define BIO_C_GET_PROXY_PARAM			121
763 #define BIO_C_SET_BUFF_READ_DATA		122 /* data to read first */
764 #define BIO_C_GET_ACCEPT			124
765 #define BIO_C_SET_SSL_RENEGOTIATE_BYTES		125
766 #define BIO_C_GET_SSL_NUM_RENEGOTIATES		126
767 #define BIO_C_SET_SSL_RENEGOTIATE_TIMEOUT	127
768 #define BIO_C_FILE_SEEK				128
769 #define BIO_C_GET_CIPHER_CTX			129
770 #define BIO_C_SET_BUF_MEM_EOF_RETURN		130/*return end of input value*/
771 #define BIO_C_SET_BIND_MODE			131
772 #define BIO_C_GET_BIND_MODE			132
773 #define BIO_C_FILE_TELL				133
774 #define BIO_C_GET_SOCKS				134
775 #define BIO_C_SET_SOCKS				135
776 
777 #define BIO_C_SET_WRITE_BUF_SIZE		136/* for BIO_s_bio */
778 #define BIO_C_GET_WRITE_BUF_SIZE		137
779 #define BIO_C_GET_WRITE_GUARANTEE		140
780 #define BIO_C_GET_READ_REQUEST			141
781 #define BIO_C_SHUTDOWN_WR			142
782 #define BIO_C_NREAD0				143
783 #define BIO_C_NREAD				144
784 #define BIO_C_NWRITE0				145
785 #define BIO_C_NWRITE				146
786 #define BIO_C_RESET_READ_REQUEST		147
787 #define BIO_C_SET_MD_CTX			148
788 
789 #define BIO_C_SET_PREFIX			149
790 #define BIO_C_GET_PREFIX			150
791 #define BIO_C_SET_SUFFIX			151
792 #define BIO_C_GET_SUFFIX			152
793 
794 #define BIO_C_SET_EX_ARG			153
795 #define BIO_C_GET_EX_ARG			154
796 
797 
798 #if defined(__cplusplus)
799 }  /* extern C */
800 
801 extern "C++" {
802 
803 namespace bssl {
804 
805 BORINGSSL_MAKE_DELETER(BIO, BIO_free)
806 
807 }  // namespace bssl
808 
809 }  /* extern C++ */
810 
811 #endif
812 
813 #define BIO_R_BAD_FOPEN_MODE 100
814 #define BIO_R_BROKEN_PIPE 101
815 #define BIO_R_CONNECT_ERROR 102
816 #define BIO_R_ERROR_SETTING_NBIO 103
817 #define BIO_R_INVALID_ARGUMENT 104
818 #define BIO_R_IN_USE 105
819 #define BIO_R_KEEPALIVE 106
820 #define BIO_R_NBIO_CONNECT_ERROR 107
821 #define BIO_R_NO_HOSTNAME_SPECIFIED 108
822 #define BIO_R_NO_PORT_SPECIFIED 109
823 #define BIO_R_NO_SUCH_FILE 110
824 #define BIO_R_NULL_PARAMETER 111
825 #define BIO_R_SYS_LIB 112
826 #define BIO_R_UNABLE_TO_CREATE_SOCKET 113
827 #define BIO_R_UNINITIALIZED 114
828 #define BIO_R_UNSUPPORTED_METHOD 115
829 #define BIO_R_WRITE_TO_READ_ONLY_BIO 116
830 
831 #endif  /* OPENSSL_HEADER_BIO_H */
832