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Refactor the LogContext type.

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LogContext is now the owner of the logevent() function that back ends
and so forth are constantly calling. Previously, logevent was owned by
the Frontend, which would store the message into its list for the GUI
Event Log dialog (or print it to standard error, or whatever) and then
pass it _back_ to LogContext to write to the currently open log file.
Now it's the other way round: LogContext gets the message from the
back end first, writes it to its log file if it feels so inclined, and
communicates it back to the front end.

This means that lots of parts of the back end system no longer need to
have a pointer to a full-on Frontend; the only thing they needed it
for was logging, so now they just have a LogContext (which many of
them had to have anyway, e.g. for logging SSH packets or session
traffic).

LogContext itself also doesn't get a full Frontend pointer any more:
it now talks back to the front end via a little vtable of its own
called LogPolicy, which contains the method that passes Event Log
entries through, the old askappend() function that decides whether to
truncate a pre-existing log file, and an emergency function for
printing an especially prominent message if the log file can't be
created. One minor nice effect of this is that console and GUI apps
can implement that last function subtly differently, so that Unix
console apps can write it with a plain \n instead of the \r\n
(harmless but inelegant) that the old centralised implementation
generated.

One other consequence of this is that the LogContext has to be
provided to backend_init() so that it's available to backends from the
instant of creation, rather than being provided via a separate API
call a couple of function calls later, because backends have typically
started doing things that need logging (like making network
connections) before the call to backend_provide_logctx. Fortunately,
there's no case in the whole code base where we don't already have
logctx by the time we make a backend (so I don't actually remember why
I ever delayed providing one). So that shortens the backend API by one
function, which is always nice.

While I'm tidying up, I've also moved the printf-style logeventf() and
the handy logevent_and_free() into logging.c, instead of having copies
of them scattered around other places. This has also let me remove
some stub functions from a couple of outlying applications like
Pageant. Finally, I've removed the pointless "_tag" at the end of
LogContext's official struct name.
This commit is contained in:
Simon Tatham
2018-10-10 19:26:18 +01:00
parent 1b67ec2963
commit ad0c502cef
47 changed files with 363 additions and 440 deletions
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80
putty.h
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@ -480,7 +480,8 @@ struct Backend {
};
struct BackendVtable {
const char *(*init) (Frontend *frontend, Backend **backend_out,
Conf *conf, const char *host, int port,
LogContext *logctx, Conf *conf,
const char *host, int port,
char **realhost, int nodelay, int keepalive);
void (*free) (Backend *be);
@ -501,7 +502,6 @@ struct BackendVtable {
int (*sendok) (Backend *be);
int (*ldisc_option_state) (Backend *be, int);
void (*provide_ldisc) (Backend *be, Ldisc *ldisc);
void (*provide_logctx) (Backend *be, LogContext *logctx);
/* Tells the back end that the front end buffer is clearing. */
void (*unthrottle) (Backend *be, int bufsize);
int (*cfg_info) (Backend *be);
@ -515,8 +515,8 @@ struct BackendVtable {
int default_port;
};
#define backend_init(vt, fe, out, conf, host, port, rhost, nd, ka) \
((vt)->init(fe, out, conf, host, port, rhost, nd, ka))
#define backend_init(vt, fe, out, logctx, conf, host, port, rhost, nd, ka) \
((vt)->init(fe, out, logctx, conf, host, port, rhost, nd, ka))
#define backend_free(be) ((be)->vt->free(be))
#define backend_reconfig(be, conf) ((be)->vt->reconfig(be, conf))
#define backend_send(be, buf, len) ((be)->vt->send(be, buf, len))
@ -530,8 +530,6 @@ struct BackendVtable {
#define backend_ldisc_option_state(be, opt) \
((be)->vt->ldisc_option_state(be, opt))
#define backend_provide_ldisc(be, ldisc) ((be)->vt->provide_ldisc(be, ldisc))
#define backend_provide_logctx(be, logctx) \
((be)->vt->provide_logctx(be, logctx))
#define backend_unthrottle(be, bufsize) ((be)->vt->unthrottle(be, bufsize))
#define backend_cfg_info(be) ((be)->vt->cfg_info(be))
@ -1170,14 +1168,64 @@ int format_arrow_key(char *buf, Terminal *term, int xkey, int ctrl);
/*
* Exports from logging.c.
*/
LogContext *log_init(Frontend *frontend, Conf *conf);
struct LogPolicyVtable {
/*
* Pass Event Log entries on from LogContext to the front end,
* which might write them to standard error or save them for a GUI
* list box or other things.
*/
void (*eventlog)(LogPolicy *lp, const char *event);
/*
* Ask what to do about the specified output log file already
* existing. Can return four values:
*
* - 2 means overwrite the log file
* - 1 means append to the log file
* - 0 means cancel logging for this session
* - -1 means please wait, and callback() will be called with one
* of those options.
*/
int (*askappend)(LogPolicy *lp, Filename *filename,
void (*callback)(void *ctx, int result), void *ctx);
/*
* Emergency logging when the log file itself can't be opened,
* which typically means we want to shout about it more loudly
* than a mere Event Log entry.
*
* One reasonable option is to send it to the same place that
* stderr output from the main session goes (so, either a console
* tool's actual stderr, or a terminal window). In many cases this
* is unlikely to cause this error message to turn up
* embarrassingly in a log file of real server output, because the
* whole point is that we haven't managed to open any such log
* file :-)
*/
void (*logging_error)(LogPolicy *lp, const char *event);
};
struct LogPolicy {
const LogPolicyVtable *vt;
};
#define lp_eventlog(lp, event) ((lp)->vt->eventlog(lp, event))
#define lp_askappend(lp, fn, cb, ctx) ((lp)->vt->askappend(lp, fn, cb, ctx))
#define lp_logging_error(lp, event) ((lp)->vt->logging_error(lp, event))
LogContext *log_init(LogPolicy *lp, Conf *conf);
void log_free(LogContext *logctx);
void log_reconfig(LogContext *logctx, Conf *conf);
void logfopen(LogContext *logctx);
void logfclose(LogContext *logctx);
void logtraffic(LogContext *logctx, unsigned char c, int logmode);
void logflush(LogContext *logctx);
void log_eventlog(LogContext *logctx, const char *string);
void logevent(LogContext *logctx, const char *event);
void logeventf(LogContext *logctx, const char *fmt, ...);
/*
* Pass a dynamically allocated string to logevent and immediately
* free it. Intended for use by wrapper macros which pass the return
* value of dupprintf straight to this.
*/
void logevent_and_free(LogContext *logctx, char *event);
enum { PKT_INCOMING, PKT_OUTGOING };
enum { PKTLOG_EMIT, PKTLOG_BLANK, PKTLOG_OMIT };
struct logblank_t {
@ -1191,6 +1239,10 @@ void log_packet(LogContext *logctx, int direction, int type,
const unsigned long *sequence,
unsigned downstream_id, const char *additional_log_text);
/* This is defined by applications that have an obvious logging
* destination like standard error or the GUI. */
extern LogPolicy default_logpolicy[1];
/*
* Exports from testback.c
*/
@ -1352,7 +1404,6 @@ int wc_unescape(char *output, const char *wildcard);
/*
* Exports from frontend (windlg.c etc)
*/
void logevent(Frontend *frontend, const char *);
void pgp_fingerprints(void);
/*
* verify_ssh_host_key() can return one of three values:
@ -1386,16 +1437,6 @@ int askalg(Frontend *frontend, const char *algtype, const char *algname,
void (*callback)(void *ctx, int result), void *ctx);
int askhk(Frontend *frontend, const char *algname, const char *betteralgs,
void (*callback)(void *ctx, int result), void *ctx);
/*
* askappend can return four values:
*
* - 2 means overwrite the log file
* - 1 means append to the log file
* - 0 means cancel logging for this session
* - -1 means please wait.
*/
int askappend(Frontend *frontend, Filename *filename,
void (*callback)(void *ctx, int result), void *ctx);
/*
* Exports from console frontends (wincons.c, uxcons.c)
@ -1403,7 +1444,6 @@ int askappend(Frontend *frontend, Filename *filename,
*/
extern int console_batch_mode;
int console_get_userpass_input(prompts_t *p);
void console_provide_logctx(LogContext *logctx);
int is_interactive(void);
/*