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putty-source/ssh2connection.h
Simon Tatham 3214563d8e Convert a lot of 'int' variables to 'bool'. 
My normal habit these days, in new code, is to treat int and bool as
_almost_ completely separate types. I'm still willing to use C's
implicit test for zero on an integer (e.g. 'if (!blob.len)' is fine,
no need to spell it out as blob.len != 0), but generally, if a
variable is going to be conceptually a boolean, I like to declare it
bool and assign to it using 'true' or 'false' rather than 0 or 1.

PuTTY is an exception, because it predates the C99 bool, and I've
stuck to its existing coding style even when adding new code to it.
But it's been annoying me more and more, so now that I've decided C99
bool is an acceptable thing to require from our toolchain in the first
place, here's a quite thorough trawl through the source doing
'boolification'. Many variables and function parameters are now typed
as bool rather than int; many assignments of 0 or 1 to those variables
are now spelled 'true' or 'false'.

I managed this thorough conversion with the help of a custom clang
plugin that I wrote to trawl the AST and apply heuristics to point out
where things might want changing. So I've even managed to do a decent
job on parts of the code I haven't looked at in years!

To make the plugin's work easier, I pushed platform front ends
generally in the direction of using standard 'bool' in preference to
platform-specific boolean types like Windows BOOL or GTK's gboolean;
I've left the platform booleans in places they _have_ to be for the
platform APIs to work right, but variables only used by my own code
have been converted wherever I found them.

In a few places there are int values that look very like booleans in
_most_ of the places they're used, but have a rarely-used third value,
or a distinction between different nonzero values that most users
don't care about. In these cases, I've _removed_ uses of 'true' and
'false' for the return values, to emphasise that there's something
more subtle going on than a simple boolean answer:
 - the 'multisel' field in dialog.h's list box structure, for which
   the GTK front end in particular recognises a difference between 1
   and 2 but nearly everything else treats as boolean
 - the 'urgent' parameter to plug_receive, where 1 vs 2 tells you
   something about the specific location of the urgent pointer, but
   most clients only care about 0 vs 'something nonzero'
 - the return value of wc_match, where -1 indicates a syntax error in
   the wildcard.
 - the return values from SSH-1 RSA-key loading functions, which use
   -1 for 'wrong passphrase' and 0 for all other failures (so any
   caller which already knows it's not loading an _encrypted private_
   key can treat them as boolean)
 - term->esc_query, and the 'query' parameter in toggle_mode in
   terminal.c, which _usually_ hold 0 for ESC[123h or 1 for ESC[?123h,
   but can also hold -1 for some other intervening character that we
   don't support.

In a few places there's an integer that I haven't turned into a bool
even though it really _can_ only take values 0 or 1 (and, as above,
tried to make the call sites consistent in not calling those values
true and false), on the grounds that I thought it would make it more
confusing to imply that the 0 value was in some sense 'negative' or
bad and the 1 positive or good:
 - the return value of plug_accepting uses the POSIXish convention of
   0=success and nonzero=error; I think if I made it bool then I'd
   also want to reverse its sense, and that's a job for a separate
   piece of work.
 - the 'screen' parameter to lineptr() in terminal.c, where 0 and 1
   represent the default and alternate screens. There's no obvious
   reason why one of those should be considered 'true' or 'positive'
   or 'success' - they're just indices - so I've left it as int.

ssh_scp_recv had particularly confusing semantics for its previous int
return value: its call sites used '<= 0' to check for error, but it
never actually returned a negative number, just 0 or 1. Now the
function and its call sites agree that it's a bool.

In a couple of places I've renamed variables called 'ret', because I
don't like that name any more - it's unclear whether it means the
return value (in preparation) for the _containing_ function or the
return value received from a subroutine call, and occasionally I've
accidentally used the same variable for both and introduced a bug. So
where one of those got in my way, I've renamed it to 'toret' or 'retd'
(the latter short for 'returned') in line with my usual modern
practice, but I haven't done a thorough job of finding all of them.

Finally, one amusing side effect of doing this is that I've had to
separate quite a few chained assignments. It used to be perfectly fine
to write 'a = b = c = TRUE' when a,b,c were int and TRUE was just a
the 'true' defined by stdbool.h, that idiom provokes a warning from
gcc: 'suggest parentheses around assignment used as truth value'!
2018-11-03 13:45:00 +00:00

232 lines
7.9 KiB
C
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#ifndef PUTTY_SSH2CONNECTION_H
#define PUTTY_SSH2CONNECTION_H
struct outstanding_channel_request;
struct outstanding_global_request;
struct ssh2_connection_state {
int crState;
Ssh *ssh;
ssh_sharing_state *connshare;
char *peer_verstring;
mainchan *mainchan;
SshChannel *mainchan_sc;
bool ldisc_opts[LD_N_OPTIONS];
int session_attempt, session_status;
int term_width, term_height;
bool want_user_input;
bool ssh_is_simple;
bool persistent;
Conf *conf;
tree234 *channels; /* indexed by local id */
bool all_channels_throttled;
bool X11_fwd_enabled;
tree234 *x11authtree;
bool got_pty;
bool agent_fwd_enabled;
tree234 *rportfwds;
PortFwdManager *portfwdmgr;
bool portfwdmgr_configured;
const SftpServerVtable *sftpserver_vt;
/*
* These store the list of global requests that we're waiting for
* replies to. (REQUEST_FAILURE doesn't come with any indication
* of what message caused it, so we have to keep track of the
* queue ourselves.)
*/
struct outstanding_global_request *globreq_head, *globreq_tail;
ConnectionLayer cl;
PacketProtocolLayer ppl;
};
typedef void (*gr_handler_fn_t)(struct ssh2_connection_state *s,
PktIn *pktin, void *ctx);
void ssh2_queue_global_request_handler(
struct ssh2_connection_state *s, gr_handler_fn_t handler, void *ctx);
struct ssh2_channel {
struct ssh2_connection_state *connlayer;
unsigned remoteid, localid;
int type;
/* True if we opened this channel but server hasn't confirmed. */
bool halfopen;
/* Bitmap of whether we've sent/received CHANNEL_EOF and
* CHANNEL_CLOSE. */
#define CLOSES_SENT_EOF 1
#define CLOSES_SENT_CLOSE 2
#define CLOSES_RCVD_EOF 4
#define CLOSES_RCVD_CLOSE 8
int closes;
/*
* This flag indicates that an EOF is pending on the outgoing side
* of the channel: that is, wherever we're getting the data for
* this channel has sent us some data followed by EOF. We can't
* actually send the EOF until we've finished sending the data, so
* we set this flag instead to remind us to do so once our buffer
* is clear.
*/
bool pending_eof;
/*
* True if this channel is causing the underlying connection to be
* throttled.
*/
bool throttling_conn;
/*
* True if we currently have backed-up data on the direction of
* this channel pointing out of the SSH connection, and therefore
* would prefer the 'Channel' implementation not to read further
* local input if possible.
*/
bool throttled_by_backlog;
bufchain outbuffer, errbuffer;
unsigned remwindow, remmaxpkt;
/* locwindow is signed so we can cope with excess data. */
int locwindow, locmaxwin;
/*
* remlocwin is the amount of local window that we think
* the remote end had available to it after it sent the
* last data packet or window adjust ack.
*/
int remlocwin;
/*
* These store the list of channel requests that we're waiting for
* replies to. (CHANNEL_FAILURE doesn't come with any indication
* of what message caused it, so we have to keep track of the
* queue ourselves.)
*/
struct outstanding_channel_request *chanreq_head, *chanreq_tail;
enum { THROTTLED, UNTHROTTLING, UNTHROTTLED } throttle_state;
ssh_sharing_connstate *sharectx; /* sharing context, if this is a
* downstream channel */
Channel *chan; /* handle the client side of this channel, if not */
SshChannel sc; /* entry point for chan to talk back to */
};
typedef void (*cr_handler_fn_t)(struct ssh2_channel *, PktIn *, void *);
void ssh2_channel_init(struct ssh2_channel *c);
PktOut *ssh2_chanreq_init(struct ssh2_channel *c, const char *type,
cr_handler_fn_t handler, void *ctx);
typedef enum ChanopenOutcome {
CHANOPEN_RESULT_FAILURE,
CHANOPEN_RESULT_SUCCESS,
CHANOPEN_RESULT_DOWNSTREAM,
} ChanopenOutcome;
typedef struct ChanopenResult {
ChanopenOutcome outcome;
union {
struct {
char *wire_message; /* must be freed by recipient */
unsigned reason_code;
} failure;
struct {
Channel *channel;
} success;
struct {
ssh_sharing_connstate *share_ctx;
} downstream;
} u;
} ChanopenResult;
PktOut *ssh2_chanopen_init(struct ssh2_channel *c, const char *type);
PktOut *ssh2_portfwd_chanopen(
struct ssh2_connection_state *s, struct ssh2_channel *c,
const char *hostname, int port,
const char *description, const SocketPeerInfo *peerinfo);
struct ssh_rportfwd *ssh2_rportfwd_alloc(
ConnectionLayer *cl,
const char *shost, int sport, const char *dhost, int dport,
int addressfamily, const char *log_description, PortFwdRecord *pfr,
ssh_sharing_connstate *share_ctx);
void ssh2_rportfwd_remove(
ConnectionLayer *cl, struct ssh_rportfwd *rpf);
SshChannel *ssh2_session_open(ConnectionLayer *cl, Channel *chan);
SshChannel *ssh2_serverside_x11_open(
ConnectionLayer *cl, Channel *chan, const SocketPeerInfo *pi);
SshChannel *ssh2_serverside_agent_open(ConnectionLayer *cl, Channel *chan);
void ssh2channel_send_exit_status(SshChannel *c, int status);
void ssh2channel_send_exit_signal(
SshChannel *c, ptrlen signame, bool core_dumped, ptrlen msg);
void ssh2channel_send_exit_signal_numeric(
SshChannel *c, int signum, bool core_dumped, ptrlen msg);
void ssh2channel_request_x11_forwarding(
SshChannel *c, bool want_reply, const char *authproto,
const char *authdata, int screen_number, bool oneshot);
void ssh2channel_request_agent_forwarding(SshChannel *c, bool want_reply);
void ssh2channel_request_pty(
SshChannel *c, bool want_reply, Conf *conf, int w, int h);
bool ssh2channel_send_env_var(
SshChannel *c, bool want_reply, const char *var, const char *value);
void ssh2channel_start_shell(SshChannel *c, bool want_reply);
void ssh2channel_start_command(
SshChannel *c, bool want_reply, const char *command);
bool ssh2channel_start_subsystem(
SshChannel *c, bool want_reply, const char *subsystem);
bool ssh2channel_send_env_var(
SshChannel *c, bool want_reply, const char *var, const char *value);
bool ssh2channel_send_serial_break(
SshChannel *c, bool want_reply, int length);
bool ssh2channel_send_signal(
SshChannel *c, bool want_reply, const char *signame);
void ssh2channel_send_terminal_size_change(SshChannel *c, int w, int h);
#define CHANOPEN_RETURN_FAILURE(code, msgparams) do \
{ \
ChanopenResult toret; \
toret.outcome = CHANOPEN_RESULT_FAILURE; \
toret.u.failure.reason_code = code; \
toret.u.failure.wire_message = dupprintf msgparams; \
return toret; \
} while (0)
#define CHANOPEN_RETURN_SUCCESS(chan) do \
{ \
ChanopenResult toret; \
toret.outcome = CHANOPEN_RESULT_SUCCESS; \
toret.u.success.channel = chan; \
return toret; \
} while (0)
#define CHANOPEN_RETURN_DOWNSTREAM(shctx) do \
{ \
ChanopenResult toret; \
toret.outcome = CHANOPEN_RESULT_DOWNSTREAM; \
toret.u.downstream.share_ctx = shctx; \
return toret; \
} while (0)
ChanopenResult ssh2_connection_parse_channel_open(
struct ssh2_connection_state *s, ptrlen type,
PktIn *pktin, SshChannel *sc);
bool ssh2_connection_parse_global_request(
struct ssh2_connection_state *s, ptrlen type, PktIn *pktin);
#endif /* PUTTY_SSH2CONNECTION_H */
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