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mirror of https://git.tartarus.org/simon/putty.git synced 2025-01-09 17:38:00 +00:00
putty-source/defs.h
Simon Tatham 6593009b0e New utility object, StripCtrlChars.
This is for sanitising output that's going to be sent to a terminal,
if you don't want it to be able to send arbitrary escape sequences and
thereby (for example) move the cursor back up to existing text on the
screen and overprint it confusingly.

It works using the standard C library: we convert to a wide-character
string and back, and then use wctype.h to spot control characters in
the intermediate form. This means its idea of the conversion character
set is locale-based rather than any of our own charset library's fixed
settings - which is what you want if the aim is to protect your local
terminal (which we assume the system locale represents accurately).

This also means that the sanitiser strips things that will _act_ as
control characters when sent to the local terminal, whether or not
they were intended as control characters by a server that might have
had a different character set in mind. Since the main aim is to
protect the local terminal rather than to faithfully replicate the
server's intention, I think that's the right criterion.

It only strips control characters at the charset-independent layer,
like backspace, carriage return and the escape character: wctype.h
classifies those as control characters, but classifies as printing all
of the more Unicode-specific controls like bidirectional overrides.
But that's enough to prevent cursor repositioning, for example.

stripctrl.c comes with a test main() of its own, which I wasn't able
to fold into testcrypt and put in the test suite because of its
dependence on the system locale - it wouldn't be guaranteed to work
the same way on different test systems anyway.

A knock-on build tweak: because you can feed data into this sanitiser
in chunks of arbitrary size, including partial multibyte chars, I had
to use mbrtowc() for the decoding, and that means that in the 'old'
Win32 builds I have to link against the Visual Studio C++ library as
well as the C library, because for some reason that's where mbrtowc
lived in VS2003.
2019-02-20 07:27:22 +00:00

187 lines
5.9 KiB
C

/*
* defs.h: initial definitions for PuTTY.
*
* The rule about this header file is that it can't depend on any
* other header file in this code base. This is where we define
* things, as much as we can, that other headers will want to refer
* to, such as opaque structure types and their associated typedefs,
* or macros that are used by other headers.
*/
#ifndef PUTTY_DEFS_H
#define PUTTY_DEFS_H
#include <stddef.h>
#include <stdint.h>
#include <stdbool.h>
#if defined _MSC_VER && _MSC_VER < 1800
/* Work around lack of inttypes.h in older MSVC */
#define PRIx32 "x"
#define PRIu64 "I64u"
#define PRIdMAX "I64d"
#define PRIXMAX "I64X"
#define SCNu64 "I64u"
#else
#include <inttypes.h>
#endif
typedef struct conf_tag Conf;
typedef struct terminal_tag Terminal;
typedef struct Filename Filename;
typedef struct FontSpec FontSpec;
typedef struct bufchain_tag bufchain;
typedef struct strbuf strbuf;
typedef struct RSAKey RSAKey;
typedef struct BinarySink BinarySink;
typedef struct BinarySource BinarySource;
typedef struct stdio_sink stdio_sink;
typedef struct bufchain_sink bufchain_sink;
typedef struct handle_sink handle_sink;
typedef struct IdempotentCallback IdempotentCallback;
typedef struct SockAddr SockAddr;
typedef struct Socket Socket;
typedef struct Plug Plug;
typedef struct SocketPeerInfo SocketPeerInfo;
typedef struct Backend Backend;
typedef struct BackendVtable BackendVtable;
typedef struct Ldisc_tag Ldisc;
typedef struct LogContext LogContext;
typedef struct LogPolicy LogPolicy;
typedef struct LogPolicyVtable LogPolicyVtable;
typedef struct Seat Seat;
typedef struct SeatVtable SeatVtable;
typedef struct TermWin TermWin;
typedef struct TermWinVtable TermWinVtable;
typedef struct Ssh Ssh;
typedef struct mp_int mp_int;
typedef struct MontyContext MontyContext;
typedef struct WeierstrassCurve WeierstrassCurve;
typedef struct WeierstrassPoint WeierstrassPoint;
typedef struct MontgomeryCurve MontgomeryCurve;
typedef struct MontgomeryPoint MontgomeryPoint;
typedef struct EdwardsCurve EdwardsCurve;
typedef struct EdwardsPoint EdwardsPoint;
typedef struct SftpServer SftpServer;
typedef struct SftpServerVtable SftpServerVtable;
typedef struct Channel Channel;
typedef struct SshChannel SshChannel;
typedef struct mainchan mainchan;
typedef struct ssh_sharing_state ssh_sharing_state;
typedef struct ssh_sharing_connstate ssh_sharing_connstate;
typedef struct share_channel share_channel;
typedef struct PortFwdManager PortFwdManager;
typedef struct PortFwdRecord PortFwdRecord;
typedef struct ConnectionLayer ConnectionLayer;
typedef struct prng prng;
typedef struct ssh_hashalg ssh_hashalg;
typedef struct ssh_hash ssh_hash;
typedef struct ssh_kex ssh_kex;
typedef struct ssh_kexes ssh_kexes;
typedef struct ssh_keyalg ssh_keyalg;
typedef struct ssh_key ssh_key;
typedef struct ssh_compressor ssh_compressor;
typedef struct ssh_decompressor ssh_decompressor;
typedef struct ssh_compression_alg ssh_compression_alg;
typedef struct ssh2_userkey ssh2_userkey;
typedef struct ssh2_macalg ssh2_macalg;
typedef struct ssh2_mac ssh2_mac;
typedef struct ssh_cipheralg ssh_cipheralg;
typedef struct ssh_cipher ssh_cipher;
typedef struct ssh2_ciphers ssh2_ciphers;
typedef struct dh_ctx dh_ctx;
typedef struct ecdh_key ecdh_key;
typedef struct dlgparam dlgparam;
typedef struct settings_w settings_w;
typedef struct settings_r settings_r;
typedef struct settings_e settings_e;
typedef struct SessionSpecial SessionSpecial;
typedef struct StripCtrlChars StripCtrlChars;
/*
* A small structure wrapping up a (pointer, length) pair so that it
* can be conveniently passed to or from a function.
*/
typedef struct ptrlen {
const void *ptr;
size_t len;
} ptrlen;
typedef struct logblank_t logblank_t;
typedef struct BinaryPacketProtocol BinaryPacketProtocol;
typedef struct PacketProtocolLayer PacketProtocolLayer;
/* Do a compile-time type-check of 'to_check' (without evaluating it),
* as a side effect of returning the value 'to_return'. Note that
* although this macro double-*expands* to_return, it always
* *evaluates* exactly one copy of it, so it's side-effect safe. */
#define TYPECHECK(to_check, to_return) \
(sizeof(to_check) ? (to_return) : (to_return))
/* Return a pointer to the object of structure type 'type' whose field
* with name 'field' is pointed at by 'object'. */
#define container_of(object, type, field) \
TYPECHECK(object == &((type *)0)->field, \
((type *)(((char *)(object)) - offsetof(type, field))))
#if defined __GNUC__ || defined __clang__
#define NORETURN __attribute__((__noreturn__))
#else
#define NORETURN
#endif
/* ----------------------------------------------------------------------
* Platform-specific definitions.
*
* Most of these live in the per-platform header files, of which
* puttyps.h selects the appropriate one. But some of the sources
* (particularly standalone test applications) would prefer not to
* have to include a per-platform header at all, because that makes it
* more portable to platforms not supported by the code base as a
* whole (for example, compiling purely computational parts of the
* code for specialist platforms for test and analysis purposes). So
* any definition that has to affect even _those_ modules will have to
* go here, with the key constraint being that this code has to come
* to _some_ decision even if the compilation platform is not a
* recognised one at all.
*/
/* Purely computational code uses smemclr(), so we have to make the
* decision here about whether that's provided by utils.c or by a
* platform implementation. We define PLATFORM_HAS_SMEMCLR to suppress
* utils.c's definition. */
#ifdef _WINDOWS
/* Windows provides the API function 'SecureZeroMemory', which we use
* unless the user has told us not to by defining NO_SECUREZEROMEMORY. */
#ifndef NO_SECUREZEROMEMORY
#define PLATFORM_HAS_SMEMCLR
#endif
#endif
#endif /* PUTTY_DEFS_H */