mirror of
https://github.com/freebsd/freebsd-src
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libc: Add fopencookie(3) wrapper around funopen(3)
Reviewed by: jhb, oshogbo Sponsored by: EMC / Isilon Storage Division Differential Revision: https://reviews.freebsd.org/D6282
This commit is contained in:
parent
f90a20b4b8
commit
877a840c08
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=299456
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@ -58,6 +58,11 @@ typedef __ssize_t ssize_t;
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#endif
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#endif
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#ifndef _OFF64_T_DECLARED
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#define _OFF64_T_DECLARED
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typedef __off_t off64_t;
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#endif
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#if __POSIX_VISIBLE >= 200112 || __XSI_VISIBLE
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#ifndef _VA_LIST_DECLARED
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typedef __va_list va_list;
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@ -427,6 +432,18 @@ FILE *funopen(const void *,
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#define fropen(cookie, fn) funopen(cookie, fn, 0, 0, 0)
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#define fwopen(cookie, fn) funopen(cookie, 0, fn, 0, 0)
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typedef ssize_t (cookie_read_function_t)(void *, char *, size_t);
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typedef ssize_t (cookie_write_function_t)(void *, const char *, size_t);
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typedef int (cookie_seek_function_t)(void *, off64_t *, int);
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typedef int (cookie_close_function_t)(void *);
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typedef struct {
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cookie_read_function_t *read;
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cookie_write_function_t *write;
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cookie_seek_function_t *seek;
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cookie_close_function_t *close;
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} cookie_io_functions_t;
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FILE *fopencookie(void *, const char *, cookie_io_functions_t);
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/*
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* Portability hacks. See <sys/types.h>.
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*/
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@ -8,7 +8,8 @@ SRCS+= _flock_stub.c asprintf.c clrerr.c dprintf.c \
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fclose.c fcloseall.c fdopen.c \
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feof.c ferror.c fflush.c fgetc.c fgetln.c fgetpos.c fgets.c fgetwc.c \
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fgetwln.c fgetws.c \
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fileno.c findfp.c flags.c fmemopen.c fopen.c fprintf.c fpurge.c \
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fileno.c findfp.c flags.c fmemopen.c fopen.c \
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fopencookie.c fprintf.c fpurge.c \
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fputc.c fputs.c \
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fputwc.c fputws.c fread.c freopen.c fscanf.c fseek.c fsetpos.c \
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ftell.c funopen.c fvwrite.c fwalk.c fwide.c fwprintf.c fwscanf.c \
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@ -35,7 +36,7 @@ SYM_MAPS+= ${LIBC_SRCTOP}/stdio/Symbol.map
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MAN+= fclose.3 ferror.3 fflush.3 fgetln.3 fgets.3 fgetwln.3 fgetws.3 \
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flockfile.3 \
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fopen.3 fputs.3 \
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fopen.3 fopencookie.3 fputs.3 \
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fputws.3 fread.3 fseek.3 funopen.3 fwide.3 getc.3 \
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getline.3 getwc.3 mktemp.3 open_memstream.3 \
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printf.3 printf_l.3 putc.3 putwc.3 remove.3 scanf.3 scanf_l.3 setbuf.3 \
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156
lib/libc/stdio/fopencookie.3
Normal file
156
lib/libc/stdio/fopencookie.3
Normal file
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@ -0,0 +1,156 @@
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.\" Copyright (c) 2016, EMC / Isilon Storage Division
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.\" All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ``AS
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.\" IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
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.\" THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR
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.\" CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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.\" EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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.\" PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
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.\" OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
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.\" WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
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.\" OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
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.\" ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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.\"
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.\" $FreeBSD$
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.\"
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.Dd May 9, 2016
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.Dt FOPENCOOKIE 3
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.Os
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.Sh NAME
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.Nm fopencookie
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.Nd open a stream
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.Sh LIBRARY
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.Lb libc
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.Sh SYNOPSIS
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.In stdio.h
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.Ft typedef ssize_t
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.Fn (cookie_read_function_t) "void *cookie" "char *buf" "size_t size"
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.Ft typedef ssize_t
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.Fn (cookie_write_function_t) "void *cookie" "const char *buf" "size_t size"
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.Ft typedef int
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.Fn (cookie_seek_function_t) "void *cookie" "off64_t *offset" "int whence"
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.Ft typedef int
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.Fn (cookie_close_function_t) "void *cookie"
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.Bd -literal
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typedef struct {
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cookie_read_function_t *read;
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cookie_write_function_t *write;
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cookie_seek_function_t *seek;
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cookie_close_function_t *close;
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} cookie_io_functions_t;
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.Ed
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.Ft FILE *
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.Fn fopencookie "void *cookie" "const char *mode" "cookie_io_functions_t io_funcs"
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.Sh DESCRIPTION
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The
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.Nm
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function
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associates a stream with up to four
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.Dq Tn I/O No functions .
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These
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.Tn I/O
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functions will be used to read, write, seek and
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close the new stream.
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.Pp
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In general, omitting a function means that any attempt to perform the
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associated operation on the resulting stream will fail.
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If the write function is omitted, data written to the stream is discarded.
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If the close function is omitted, closing the stream will flush
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any buffered output and then succeed.
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.Pp
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The calling conventions of
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.Fa read ,
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.Fa write ,
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and
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.Fa close
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must match those, respectively, of
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.Xr read 2 ,
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.Xr write 2 ,
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and
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.Xr close 2
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with the single exception that they are passed the
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.Fa cookie
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argument specified to
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.Nm
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in place of the traditional file descriptor argument.
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The
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.Fa seek
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function updates the current stream offset using
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.Fa *offset
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and
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.Fa whence .
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If
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.Fa *offset
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is non-NULL, it updates
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.Fa *offset
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with the current stream offset.
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.Pp
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.Nm
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is implemented as a thin shim around the
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.Xr funopen 3
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interface.
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Limitations, possibilities, and requirements of that interface apply to
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.Nm .
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.Sh RETURN VALUES
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Upon successful completion,
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.Nm
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returns a
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.Dv FILE
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pointer.
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Otherwise,
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.Dv NULL
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is returned and the global variable
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.Va errno
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is set to indicate the error.
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.Sh ERRORS
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.Bl -tag -width Er
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.It Bq Er EINVAL
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A bogus
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.Fa mode
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was provided to
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.Nm .
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.It Bq Er ENOMEM
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The
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.Nm
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function
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may fail and set
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.Va errno
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for any of the errors
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specified for the
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.Xr malloc 3
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routine.
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.El
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.Sh SEE ALSO
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.Xr fcntl 2 ,
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.Xr open 2 ,
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.Xr fclose 3 ,
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.Xr fopen 3 ,
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.Xr fseek 3 ,
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.Xr funopen 3
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.Sh HISTORY
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The
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.Fn funopen
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functions first appeared in
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.Bx 4.4 .
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The
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.Nm
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function first appeared in
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.Fx 11 .
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.Sh BUGS
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The
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.Nm
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function is a nonstandard glibc extension and may not be portable to systems
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other than
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.Fx
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and Linux.
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168
lib/libc/stdio/fopencookie.c
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168
lib/libc/stdio/fopencookie.c
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@ -0,0 +1,168 @@
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/*
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* Copyright (c) 2016, EMC / Isilon Storage Division
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ``AS
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* IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
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* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR
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* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
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* OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
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* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
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* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
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* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/fcntl.h>
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#include <errno.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include "local.h"
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struct fopencookie_thunk {
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void *foc_cookie;
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cookie_io_functions_t foc_io;
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};
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static int _fopencookie_read(void *, char *, int);
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static int _fopencookie_write(void *, const char *, int);
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static fpos_t _fopencookie_seek(void *, fpos_t, int);
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static int _fopencookie_close(void *);
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FILE *
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fopencookie(void *cookie, const char *mode, cookie_io_functions_t io_funcs)
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{
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int (*readfn)(void *, char *, int);
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int (*writefn)(void *, const char *, int);
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struct fopencookie_thunk *thunk;
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FILE *fp;
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int flags, oflags;
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if ((flags = __sflags(mode, &oflags)) == 0)
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return (NULL);
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thunk = malloc(sizeof(*thunk));
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if (thunk == NULL)
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return (NULL);
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thunk->foc_cookie = cookie;
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thunk->foc_io = io_funcs;
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readfn = _fopencookie_read;
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writefn = _fopencookie_write;
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if (flags == __SWR)
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readfn = NULL;
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else if (flags == __SRD)
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writefn = NULL;
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fp = funopen(thunk, readfn, writefn, _fopencookie_seek,
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_fopencookie_close);
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if (fp == NULL) {
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free(thunk);
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return (NULL);
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}
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if ((oflags & O_APPEND) != 0)
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fp->_flags |= __SAPP;
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return (fp);
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}
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static int
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_fopencookie_read(void *cookie, char *buf, int size)
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{
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struct fopencookie_thunk *thunk;
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thunk = cookie;
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/* Reads from a stream with NULL read return EOF. */
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if (thunk->foc_io.read == NULL)
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return (0);
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return ((int)thunk->foc_io.read(thunk->foc_cookie, buf, (size_t)size));
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}
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static int
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_fopencookie_write(void *cookie, const char *buf, int size)
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{
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struct fopencookie_thunk *thunk;
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thunk = cookie;
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/* Writes to a stream with NULL write discard data. */
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if (thunk->foc_io.write == NULL)
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return (size);
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return ((int)thunk->foc_io.write(thunk->foc_cookie, buf,
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(size_t)size));
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}
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static fpos_t
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_fopencookie_seek(void *cookie, fpos_t offset, int whence)
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{
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struct fopencookie_thunk *thunk;
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off64_t off64;
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int res;
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switch (whence) {
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case SEEK_SET:
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case SEEK_CUR:
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case SEEK_END:
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break;
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default:
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/* fopencookie(3) only allows these three seek modes. */
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errno = EINVAL;
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return (-1);
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}
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thunk = cookie;
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/*
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* If seek is NULL, it is not possible to perform seek operations on
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* the stream.
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*/
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if (thunk->foc_io.seek == NULL) {
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errno = ENOTSUP;
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return (-1);
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}
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off64 = (off64_t)offset;
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res = thunk->foc_io.seek(thunk->foc_cookie, &off64, whence);
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if (res < 0)
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return (res);
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return ((fpos_t)off64);
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}
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static int
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_fopencookie_close(void *cookie)
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{
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struct fopencookie_thunk *thunk;
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int ret, serrno;
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ret = 0;
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thunk = cookie;
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if (thunk->foc_io.close != NULL)
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ret = thunk->foc_io.close(thunk->foc_cookie);
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serrno = errno;
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free(thunk);
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errno = serrno;
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return (ret);
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}
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@ -30,7 +30,7 @@
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.\" @(#)funopen.3 8.1 (Berkeley) 6/9/93
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.\" $FreeBSD$
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.\"
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.Dd March 19, 2004
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.Dd May 9, 2016
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.Dt FUNOPEN 3
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.Os
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.Sh NAME
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@ -153,6 +153,7 @@ specified for the routine
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.Xr open 2 ,
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.Xr fclose 3 ,
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.Xr fopen 3 ,
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.Xr fopencookie 3 ,
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.Xr fseek 3 ,
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.Xr setbuf 3
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.Sh HISTORY
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