mirror of
https://github.com/openssl/openssl.git
synced 2024-12-15 06:01:37 +08:00
04f6b0fd91
BIO_new, etc., don't need a non-const BIO_METHOD. This allows all the built-in method tables to live in .rodata. Reviewed-by: Richard Levitte <levitte@openssl.org>
149 lines
4.3 KiB
Plaintext
149 lines
4.3 KiB
Plaintext
=pod
|
|
|
|
=head1 NAME
|
|
|
|
BIO_s_file, BIO_new_file, BIO_new_fp, BIO_set_fp, BIO_get_fp,
|
|
BIO_read_filename, BIO_write_filename, BIO_append_filename,
|
|
BIO_rw_filename - FILE bio
|
|
|
|
=head1 SYNOPSIS
|
|
|
|
#include <openssl/bio.h>
|
|
|
|
const BIO_METHOD * BIO_s_file(void);
|
|
BIO *BIO_new_file(const char *filename, const char *mode);
|
|
BIO *BIO_new_fp(FILE *stream, int flags);
|
|
|
|
BIO_set_fp(BIO *b,FILE *fp, int flags);
|
|
BIO_get_fp(BIO *b,FILE **fpp);
|
|
|
|
int BIO_read_filename(BIO *b, char *name)
|
|
int BIO_write_filename(BIO *b, char *name)
|
|
int BIO_append_filename(BIO *b, char *name)
|
|
int BIO_rw_filename(BIO *b, char *name)
|
|
|
|
=head1 DESCRIPTION
|
|
|
|
BIO_s_file() returns the BIO file method. As its name implies it
|
|
is a wrapper round the stdio FILE structure and it is a
|
|
source/sink BIO.
|
|
|
|
Calls to BIO_read() and BIO_write() read and write data to the
|
|
underlying stream. BIO_gets() and BIO_puts() are supported on file BIOs.
|
|
|
|
BIO_flush() on a file BIO calls the fflush() function on the wrapped
|
|
stream.
|
|
|
|
BIO_reset() attempts to change the file pointer to the start of file
|
|
using fseek(stream, 0, 0).
|
|
|
|
BIO_seek() sets the file pointer to position B<ofs> from start of file
|
|
using fseek(stream, ofs, 0).
|
|
|
|
BIO_eof() calls feof().
|
|
|
|
Setting the BIO_CLOSE flag calls fclose() on the stream when the BIO
|
|
is freed.
|
|
|
|
BIO_new_file() creates a new file BIO with mode B<mode> the meaning
|
|
of B<mode> is the same as the stdio function fopen(). The BIO_CLOSE
|
|
flag is set on the returned BIO.
|
|
|
|
BIO_new_fp() creates a file BIO wrapping B<stream>. Flags can be:
|
|
BIO_CLOSE, BIO_NOCLOSE (the close flag) BIO_FP_TEXT (sets the underlying
|
|
stream to text mode, default is binary: this only has any effect under
|
|
Win32).
|
|
|
|
BIO_set_fp() set the fp of a file BIO to B<fp>. B<flags> has the same
|
|
meaning as in BIO_new_fp(), it is a macro.
|
|
|
|
BIO_get_fp() retrieves the fp of a file BIO, it is a macro.
|
|
|
|
BIO_seek() is a macro that sets the position pointer to B<offset> bytes
|
|
from the start of file.
|
|
|
|
BIO_tell() returns the value of the position pointer.
|
|
|
|
BIO_read_filename(), BIO_write_filename(), BIO_append_filename() and
|
|
BIO_rw_filename() set the file BIO B<b> to use file B<name> for
|
|
reading, writing, append or read write respectively.
|
|
|
|
=head1 NOTES
|
|
|
|
When wrapping stdout, stdin or stderr the underlying stream should not
|
|
normally be closed so the BIO_NOCLOSE flag should be set.
|
|
|
|
Because the file BIO calls the underlying stdio functions any quirks
|
|
in stdio behaviour will be mirrored by the corresponding BIO.
|
|
|
|
On Windows BIO_new_files reserves for the filename argument to be
|
|
UTF-8 encoded. In other words if you have to make it work in multi-
|
|
lingual environment, encode file names in UTF-8.
|
|
|
|
=head1 EXAMPLES
|
|
|
|
File BIO "hello world":
|
|
|
|
BIO *bio_out;
|
|
bio_out = BIO_new_fp(stdout, BIO_NOCLOSE);
|
|
BIO_printf(bio_out, "Hello World\n");
|
|
|
|
Alternative technique:
|
|
|
|
BIO *bio_out;
|
|
bio_out = BIO_new(BIO_s_file());
|
|
if(bio_out == NULL) /* Error ... */
|
|
if(!BIO_set_fp(bio_out, stdout, BIO_NOCLOSE)) /* Error ... */
|
|
BIO_printf(bio_out, "Hello World\n");
|
|
|
|
Write to a file:
|
|
|
|
BIO *out;
|
|
out = BIO_new_file("filename.txt", "w");
|
|
if(!out) /* Error occurred */
|
|
BIO_printf(out, "Hello World\n");
|
|
BIO_free(out);
|
|
|
|
Alternative technique:
|
|
|
|
BIO *out;
|
|
out = BIO_new(BIO_s_file());
|
|
if(out == NULL) /* Error ... */
|
|
if(!BIO_write_filename(out, "filename.txt")) /* Error ... */
|
|
BIO_printf(out, "Hello World\n");
|
|
BIO_free(out);
|
|
|
|
=head1 RETURN VALUES
|
|
|
|
BIO_s_file() returns the file BIO method.
|
|
|
|
BIO_new_file() and BIO_new_fp() return a file BIO or NULL if an error
|
|
occurred.
|
|
|
|
BIO_set_fp() and BIO_get_fp() return 1 for success or 0 for failure
|
|
(although the current implementation never return 0).
|
|
|
|
BIO_seek() returns the same value as the underlying fseek() function:
|
|
0 for success or -1 for failure.
|
|
|
|
BIO_tell() returns the current file position.
|
|
|
|
BIO_read_filename(), BIO_write_filename(), BIO_append_filename() and
|
|
BIO_rw_filename() return 1 for success or 0 for failure.
|
|
|
|
=head1 BUGS
|
|
|
|
BIO_reset() and BIO_seek() are implemented using fseek() on the underlying
|
|
stream. The return value for fseek() is 0 for success or -1 if an error
|
|
occurred this differs from other types of BIO which will typically return
|
|
1 for success and a non positive value if an error occurred.
|
|
|
|
=head1 SEE ALSO
|
|
|
|
L<BIO_seek(3)>, L<BIO_tell(3)>,
|
|
L<BIO_reset(3)>, L<BIO_flush(3)>,
|
|
L<BIO_read(3)>,
|
|
L<BIO_write(3)>, L<BIO_puts(3)>,
|
|
L<BIO_gets(3)>, L<BIO_printf(3)>,
|
|
L<BIO_set_close(3)>, L<BIO_get_close(3)>
|