mirror of
https://git.hardenedbsd.org/hardenedbsd/HardenedBSD.git
synced 2024-11-22 11:14:18 +01:00
ea46e63863
Highlights: - Some style fixes - Bumped mbbuf in istrsenvisx() to MB_LEN_MAX to avoid VLAs - mbslength cannot go negative, so make it unsigned - Further bounds checking & fix an additional overrun, with dlen == 0 - Avoid duplicate call to wcslen(start)
271 lines
6.8 KiB
Groff
271 lines
6.8 KiB
Groff
.\" $NetBSD: unvis.3,v 1.30 2019/05/08 15:37:41 bad Exp $
|
|
.\"
|
|
.\" Copyright (c) 1989, 1991, 1993
|
|
.\" The Regents of the University of California. All rights reserved.
|
|
.\"
|
|
.\" Redistribution and use in source and binary forms, with or without
|
|
.\" modification, are permitted provided that the following conditions
|
|
.\" are met:
|
|
.\" 1. Redistributions of source code must retain the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer.
|
|
.\" 2. Redistributions in binary form must reproduce the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer in the
|
|
.\" documentation and/or other materials provided with the distribution.
|
|
.\" 3. Neither the name of the University nor the names of its contributors
|
|
.\" may be used to endorse or promote products derived from this software
|
|
.\" without specific prior written permission.
|
|
.\"
|
|
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
|
|
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
|
.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
|
|
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
|
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
|
|
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
|
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
|
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
|
|
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
|
.\" SUCH DAMAGE.
|
|
.\"
|
|
.\" @(#)unvis.3 8.2 (Berkeley) 12/11/93
|
|
.\"
|
|
.Dd May 8, 2019
|
|
.Dt UNVIS 3
|
|
.Os
|
|
.Sh NAME
|
|
.Nm unvis ,
|
|
.Nm strunvis ,
|
|
.Nm strnunvis ,
|
|
.Nm strunvisx ,
|
|
.Nm strnunvisx
|
|
.Nd decode a visual representation of characters
|
|
.Sh LIBRARY
|
|
.Lb libc
|
|
.Sh SYNOPSIS
|
|
.In vis.h
|
|
.Ft int
|
|
.Fn unvis "char *cp" "int c" "int *astate" "int flag"
|
|
.Ft int
|
|
.Fn strunvis "char *dst" "const char *src"
|
|
.Ft int
|
|
.Fn strnunvis "char *dst" "size_t dlen" "const char *src"
|
|
.Ft int
|
|
.Fn strunvisx "char *dst" "const char *src" "int flag"
|
|
.Ft int
|
|
.Fn strnunvisx "char *dst" "size_t dlen" "const char *src" "int flag"
|
|
.Sh DESCRIPTION
|
|
The
|
|
.Fn unvis ,
|
|
.Fn strunvis
|
|
and
|
|
.Fn strunvisx
|
|
functions
|
|
are used to decode a visual representation of characters, as produced
|
|
by the
|
|
.Xr vis 3
|
|
function, back into
|
|
the original form.
|
|
.Pp
|
|
The
|
|
.Fn unvis
|
|
function is called with successive characters in
|
|
.Ar c
|
|
until a valid sequence is recognized, at which time the decoded
|
|
character is available at the character pointed to by
|
|
.Ar cp .
|
|
.Pp
|
|
The
|
|
.Fn strunvis
|
|
function decodes the characters pointed to by
|
|
.Ar src
|
|
into the buffer pointed to by
|
|
.Ar dst .
|
|
The
|
|
.Fn strunvis
|
|
function simply copies
|
|
.Ar src
|
|
to
|
|
.Ar dst ,
|
|
decoding any escape sequences along the way,
|
|
and returns the number of characters placed into
|
|
.Ar dst ,
|
|
or \-1 if an
|
|
invalid escape sequence was detected.
|
|
The size of
|
|
.Ar dst
|
|
should be equal to the size of
|
|
.Ar src
|
|
(that is, no expansion takes place during decoding).
|
|
.Pp
|
|
The
|
|
.Fn strunvisx
|
|
and
|
|
.Fn strnunvisx
|
|
functions do the same as the
|
|
.Fn strunvis
|
|
and
|
|
.Fn strnunvis
|
|
functions,
|
|
but take a flag that specifies the style the string
|
|
.Ar src
|
|
is encoded with.
|
|
The meaning of the flag is the same as explained below for
|
|
.Fn unvis .
|
|
.Pp
|
|
The
|
|
.Fn unvis
|
|
function implements a state machine that can be used to decode an
|
|
arbitrary stream of bytes.
|
|
All state associated with the bytes being decoded is stored outside the
|
|
.Fn unvis
|
|
function (that is, a pointer to the state is passed in), so
|
|
calls decoding different streams can be freely intermixed.
|
|
To start decoding a stream of bytes, first initialize an integer to zero.
|
|
Call
|
|
.Fn unvis
|
|
with each successive byte, along with a pointer
|
|
to this integer, and a pointer to a destination character.
|
|
The
|
|
.Fn unvis
|
|
function has several return codes that must be handled properly.
|
|
They are:
|
|
.Bl -tag -width UNVIS_VALIDPUSH
|
|
.It Li \&0 No (zero)
|
|
Another character is necessary; nothing has been recognized yet.
|
|
.It Dv UNVIS_VALID
|
|
A valid character has been recognized and is available at the location
|
|
pointed to by
|
|
.Fa cp .
|
|
.It Dv UNVIS_VALIDPUSH
|
|
A valid character has been recognized and is available at the location
|
|
pointed to by
|
|
.Fa cp ;
|
|
however, the character currently passed in should be passed in again.
|
|
.It Dv UNVIS_NOCHAR
|
|
A valid sequence was detected, but no character was produced.
|
|
This return code is necessary to indicate a logical break between characters.
|
|
.It Dv UNVIS_SYNBAD
|
|
An invalid escape sequence was detected, or the decoder is in an unknown state.
|
|
The decoder is placed into the starting state.
|
|
.El
|
|
.Pp
|
|
When all bytes in the stream have been processed, call
|
|
.Fn unvis
|
|
one more time with flag set to
|
|
.Dv UNVIS_END
|
|
to extract any remaining character (the character passed in is ignored).
|
|
.Pp
|
|
The
|
|
.Fa flag
|
|
argument is also used to specify the encoding style of the source.
|
|
If set to
|
|
.Dv VIS_NOESCAPE
|
|
.Fn unvis
|
|
will not decode backslash escapes.
|
|
If set to
|
|
.Dv VIS_HTTPSTYLE
|
|
or
|
|
.Dv VIS_HTTP1808 ,
|
|
.Fn unvis
|
|
will decode URI strings as specified in RFC 1808.
|
|
If set to
|
|
.Dv VIS_HTTP1866 ,
|
|
.Fn unvis
|
|
will decode entity references and numeric character references
|
|
as specified in RFC 1866.
|
|
If set to
|
|
.Dv VIS_MIMESTYLE ,
|
|
.Fn unvis
|
|
will decode MIME Quoted-Printable strings as specified in RFC 2045.
|
|
If set to
|
|
.Dv VIS_NOESCAPE ,
|
|
.Fn unvis
|
|
will not decode
|
|
.Ql \e
|
|
quoted characters.
|
|
.Pp
|
|
The following code fragment illustrates a proper use of
|
|
.Fn unvis .
|
|
.Bd -literal -offset indent
|
|
int state = 0;
|
|
char out;
|
|
|
|
while ((ch = getchar()) != EOF) {
|
|
again:
|
|
switch(unvis(&out, ch, &state, 0)) {
|
|
case 0:
|
|
case UNVIS_NOCHAR:
|
|
break;
|
|
case UNVIS_VALID:
|
|
(void)putchar(out);
|
|
break;
|
|
case UNVIS_VALIDPUSH:
|
|
(void)putchar(out);
|
|
goto again;
|
|
case UNVIS_SYNBAD:
|
|
errx(EXIT_FAILURE, "Bad character sequence!");
|
|
}
|
|
}
|
|
if (unvis(&out, '\e0', &state, UNVIS_END) == UNVIS_VALID)
|
|
(void)putchar(out);
|
|
.Ed
|
|
.Sh ERRORS
|
|
The functions
|
|
.Fn strunvis ,
|
|
.Fn strnunvis ,
|
|
.Fn strunvisx ,
|
|
and
|
|
.Fn strnunvisx
|
|
will return \-1 on error and set
|
|
.Va errno
|
|
to:
|
|
.Bl -tag -width Er
|
|
.It Bq Er EINVAL
|
|
An invalid escape sequence was detected, or the decoder is in an unknown state.
|
|
.El
|
|
.Pp
|
|
In addition the functions
|
|
.Fn strnunvis
|
|
and
|
|
.Fn strnunvisx
|
|
will can also set
|
|
.Va errno
|
|
on error to:
|
|
.Bl -tag -width Er
|
|
.It Bq Er ENOSPC
|
|
Not enough space to perform the conversion.
|
|
.El
|
|
.Sh SEE ALSO
|
|
.Xr unvis 1 ,
|
|
.Xr vis 1 ,
|
|
.Xr vis 3
|
|
.Rs
|
|
.%A R. Fielding
|
|
.%T Relative Uniform Resource Locators
|
|
.%O RFC1808
|
|
.Re
|
|
.Sh HISTORY
|
|
The
|
|
.Fn unvis
|
|
function
|
|
first appeared in
|
|
.Bx 4.4 .
|
|
The
|
|
.Fn strnunvis
|
|
and
|
|
.Fn strnunvisx
|
|
functions appeared in
|
|
.Nx 6.0
|
|
and
|
|
.Fx 9.2 .
|
|
.Sh BUGS
|
|
The names
|
|
.Dv VIS_HTTP1808
|
|
and
|
|
.Dv VIS_HTTP1866
|
|
are wrong.
|
|
Percent-encoding was defined in RFC 1738, the original RFC for URL.
|
|
RFC 1866 defines HTML 2.0, an application of SGML, from which it
|
|
inherits concepts of numeric character references and entity
|
|
references.
|