2 * Platform-independent routines shared between all PuTTY programs.
14 * Parse a string block size specification. This is approximately a
15 * subset of the block size specs supported by GNU fileutils:
19 * All numbers are decimal, and suffixes refer to powers of two.
22 unsigned long parse_blocksize(const char *bs
)
25 unsigned long r
= strtoul(bs
, &suf
, 10);
27 while (*suf
&& isspace((unsigned char)*suf
)) suf
++;
36 r
*= 1024ul * 1024ul * 1024ul;
47 * Parse a ^C style character specification.
48 * Returns NULL in `next' if we didn't recognise it as a control character,
49 * in which case `c' should be ignored.
50 * The precise current parsing is an oddity inherited from the terminal
51 * answerback-string parsing code. All sequences start with ^; all except
52 * ^<123> are two characters. The ones that are worth keeping are probably:
56 * <num> specified by number (decimal, 0octal, 0xHEX)
59 char ctrlparse(char *s
, char **next
)
68 } else if (*s
== '<') {
70 c
= (char)strtol(s
, next
, 0);
71 if ((*next
== s
) || (**next
!= '>')) {
76 } else if (*s
>= 'a' && *s
<= 'z') {
79 } else if ((*s
>= '@' && *s
<= '_') || *s
== '?' || (*s
& 0x80)) {
82 } else if (*s
== '~') {
90 prompts_t
*new_prompts(void *frontend
)
92 prompts_t
*p
= snew(prompts_t
);
95 p
->frontend
= frontend
;
97 p
->to_server
= TRUE
; /* to be on the safe side */
98 p
->name
= p
->instruction
= NULL
;
99 p
->name_reqd
= p
->instr_reqd
= FALSE
;
102 void add_prompt(prompts_t
*p
, char *promptstr
, int echo
)
104 prompt_t
*pr
= snew(prompt_t
);
105 pr
->prompt
= promptstr
;
110 p
->prompts
= sresize(p
->prompts
, p
->n_prompts
, prompt_t
*);
111 p
->prompts
[p
->n_prompts
-1] = pr
;
113 void prompt_ensure_result_size(prompt_t
*pr
, int newlen
)
115 if ((int)pr
->resultsize
< newlen
) {
117 newlen
= newlen
* 5 / 4 + 512; /* avoid too many small allocs */
120 * We don't use sresize / realloc here, because we will be
121 * storing sensitive stuff like passwords in here, and we want
122 * to make sure that the data doesn't get copied around in
123 * memory without the old copy being destroyed.
125 newbuf
= snewn(newlen
, char);
126 memcpy(newbuf
, pr
->result
, pr
->resultsize
);
127 smemclr(pr
->result
, pr
->resultsize
);
130 pr
->resultsize
= newlen
;
133 void prompt_set_result(prompt_t
*pr
, const char *newstr
)
135 prompt_ensure_result_size(pr
, strlen(newstr
) + 1);
136 strcpy(pr
->result
, newstr
);
138 void free_prompts(prompts_t
*p
)
141 for (i
=0; i
< p
->n_prompts
; i
++) {
142 prompt_t
*pr
= p
->prompts
[i
];
143 smemclr(pr
->result
, pr
->resultsize
); /* burn the evidence */
150 sfree(p
->instruction
);
154 /* ----------------------------------------------------------------------
155 * String handling routines.
158 char *dupstr(const char *s
)
163 p
= snewn(len
+ 1, char);
169 /* Allocate the concatenation of N strings. Terminate arg list with NULL. */
170 char *dupcat(const char *s1
, ...)
179 sn
= va_arg(ap
, char *);
186 p
= snewn(len
+ 1, char);
192 sn
= va_arg(ap
, char *);
203 void burnstr(char *string
) /* sfree(str), only clear it first */
206 smemclr(string
, strlen(string
));
211 int toint(unsigned u
)
214 * Convert an unsigned to an int, without running into the
215 * undefined behaviour which happens by the strict C standard if
216 * the value overflows. You'd hope that sensible compilers would
217 * do the sensible thing in response to a cast, but actually I
218 * don't trust modern compilers not to do silly things like
219 * assuming that _obviously_ you wouldn't have caused an overflow
220 * and so they can elide an 'if (i < 0)' test immediately after
223 * Sensible compilers ought of course to optimise this entire
224 * function into 'just return the input value'!
226 if (u
<= (unsigned)INT_MAX
)
228 else if (u
>= (unsigned)INT_MIN
) /* wrap in cast _to_ unsigned is OK */
229 return INT_MIN
+ (int)(u
- (unsigned)INT_MIN
);
231 return INT_MIN
; /* fallback; should never occur on binary machines */
235 * Do an sprintf(), but into a custom-allocated buffer.
237 * Currently I'm doing this via vsnprintf. This has worked so far,
238 * but it's not good, because vsnprintf is not available on all
239 * platforms. There's an ifdef to use `_vsnprintf', which seems
240 * to be the local name for it on Windows. Other platforms may
241 * lack it completely, in which case it'll be time to rewrite
242 * this function in a totally different way.
244 * The only `properly' portable solution I can think of is to
245 * implement my own format string scanner, which figures out an
246 * upper bound for the length of each formatting directive,
247 * allocates the buffer as it goes along, and calls sprintf() to
248 * actually process each directive. If I ever need to actually do
249 * this, some caveats:
251 * - It's very hard to find a reliable upper bound for
252 * floating-point values. %f, in particular, when supplied with
253 * a number near to the upper or lower limit of representable
254 * numbers, could easily take several hundred characters. It's
255 * probably feasible to predict this statically using the
256 * constants in <float.h>, or even to predict it dynamically by
257 * looking at the exponent of the specific float provided, but
260 * - Don't forget to _check_, after calling sprintf, that it's
261 * used at most the amount of space we had available.
263 * - Fault any formatting directive we don't fully understand. The
264 * aim here is to _guarantee_ that we never overflow the buffer,
265 * because this is a security-critical function. If we see a
266 * directive we don't know about, we should panic and die rather
269 char *dupprintf(const char *fmt
, ...)
274 ret
= dupvprintf(fmt
, ap
);
278 char *dupvprintf(const char *fmt
, va_list ap
)
283 buf
= snewn(512, char);
288 #define vsnprintf _vsnprintf
291 /* Use the `va_copy' macro mandated by C99, if present.
292 * XXX some environments may have this as __va_copy() */
295 len
= vsnprintf(buf
, size
, fmt
, aq
);
298 /* Ugh. No va_copy macro, so do something nasty.
299 * Technically, you can't reuse a va_list like this: it is left
300 * unspecified whether advancing a va_list pointer modifies its
301 * value or something it points to, so on some platforms calling
302 * vsnprintf twice on the same va_list might fail hideously
303 * (indeed, it has been observed to).
304 * XXX the autoconf manual suggests that using memcpy() will give
305 * "maximum portability". */
306 len
= vsnprintf(buf
, size
, fmt
, ap
);
308 if (len
>= 0 && len
< size
) {
309 /* This is the C99-specified criterion for snprintf to have
310 * been completely successful. */
312 } else if (len
> 0) {
313 /* This is the C99 error condition: the returned length is
314 * the required buffer size not counting the NUL. */
317 /* This is the pre-C99 glibc error condition: <0 means the
318 * buffer wasn't big enough, so we enlarge it a bit and hope. */
321 buf
= sresize(buf
, size
, char);
326 * Read an entire line of text from a file. Return a buffer
327 * malloced to be as big as necessary (caller must free).
329 char *fgetline(FILE *fp
)
331 char *ret
= snewn(512, char);
332 int size
= 512, len
= 0;
333 while (fgets(ret
+ len
, size
- len
, fp
)) {
334 len
+= strlen(ret
+ len
);
335 if (ret
[len
-1] == '\n')
336 break; /* got a newline, we're done */
338 ret
= sresize(ret
, size
, char);
340 if (len
== 0) { /* first fgets returned NULL */
348 /* ----------------------------------------------------------------------
349 * Base64 encoding routine. This is required in public-key writing
350 * but also in HTTP proxy handling, so it's centralised here.
353 void base64_encode_atom(unsigned char *data
, int n
, char *out
)
355 static const char base64_chars
[] =
356 "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
360 word
= data
[0] << 16;
362 word
|= data
[1] << 8;
365 out
[0] = base64_chars
[(word
>> 18) & 0x3F];
366 out
[1] = base64_chars
[(word
>> 12) & 0x3F];
368 out
[2] = base64_chars
[(word
>> 6) & 0x3F];
372 out
[3] = base64_chars
[word
& 0x3F];
377 /* ----------------------------------------------------------------------
378 * Generic routines to deal with send buffers: a linked list of
379 * smallish blocks, with the operations
381 * - add an arbitrary amount of data to the end of the list
382 * - remove the first N bytes from the list
383 * - return a (pointer,length) pair giving some initial data in
384 * the list, suitable for passing to a send or write system
386 * - retrieve a larger amount of initial data from the list
387 * - return the current size of the buffer chain in bytes
390 #define BUFFER_MIN_GRANULE 512
392 struct bufchain_granule
{
393 struct bufchain_granule
*next
;
394 char *bufpos
, *bufend
, *bufmax
;
397 void bufchain_init(bufchain
*ch
)
399 ch
->head
= ch
->tail
= NULL
;
403 void bufchain_clear(bufchain
*ch
)
405 struct bufchain_granule
*b
;
408 ch
->head
= ch
->head
->next
;
415 int bufchain_size(bufchain
*ch
)
417 return ch
->buffersize
;
420 void bufchain_add(bufchain
*ch
, const void *data
, int len
)
422 const char *buf
= (const char *)data
;
424 if (len
== 0) return;
426 ch
->buffersize
+= len
;
429 if (ch
->tail
&& ch
->tail
->bufend
< ch
->tail
->bufmax
) {
430 int copylen
= min(len
, ch
->tail
->bufmax
- ch
->tail
->bufend
);
431 memcpy(ch
->tail
->bufend
, buf
, copylen
);
434 ch
->tail
->bufend
+= copylen
;
438 max(sizeof(struct bufchain_granule
) + len
, BUFFER_MIN_GRANULE
);
439 struct bufchain_granule
*newbuf
;
440 newbuf
= smalloc(grainlen
);
441 newbuf
->bufpos
= newbuf
->bufend
=
442 (char *)newbuf
+ sizeof(struct bufchain_granule
);
443 newbuf
->bufmax
= (char *)newbuf
+ grainlen
;
446 ch
->tail
->next
= newbuf
;
454 void bufchain_consume(bufchain
*ch
, int len
)
456 struct bufchain_granule
*tmp
;
458 assert(ch
->buffersize
>= len
);
461 assert(ch
->head
!= NULL
);
462 if (remlen
>= ch
->head
->bufend
- ch
->head
->bufpos
) {
463 remlen
= ch
->head
->bufend
- ch
->head
->bufpos
;
465 ch
->head
= tmp
->next
;
470 ch
->head
->bufpos
+= remlen
;
471 ch
->buffersize
-= remlen
;
476 void bufchain_prefix(bufchain
*ch
, void **data
, int *len
)
478 *len
= ch
->head
->bufend
- ch
->head
->bufpos
;
479 *data
= ch
->head
->bufpos
;
482 void bufchain_fetch(bufchain
*ch
, void *data
, int len
)
484 struct bufchain_granule
*tmp
;
485 char *data_c
= (char *)data
;
489 assert(ch
->buffersize
>= len
);
494 if (remlen
>= tmp
->bufend
- tmp
->bufpos
)
495 remlen
= tmp
->bufend
- tmp
->bufpos
;
496 memcpy(data_c
, tmp
->bufpos
, remlen
);
504 /* ----------------------------------------------------------------------
505 * My own versions of malloc, realloc and free. Because I want
506 * malloc and realloc to bomb out and exit the program if they run
507 * out of memory, realloc to reliably call malloc if passed a NULL
508 * pointer, and free to reliably do nothing if passed a NULL
509 * pointer. We can also put trace printouts in, if we need to; and
510 * we can also replace the allocator with an ElectricFence-like
515 void *minefield_c_malloc(size_t size
);
516 void minefield_c_free(void *p
);
517 void *minefield_c_realloc(void *p
, size_t size
);
521 static FILE *fp
= NULL
;
523 static char *mlog_file
= NULL
;
524 static int mlog_line
= 0;
526 void mlog(char *file
, int line
)
531 fp
= fopen("putty_mem.log", "w");
532 setvbuf(fp
, NULL
, _IONBF
, BUFSIZ
);
535 fprintf(fp
, "%s:%d: ", file
, line
);
539 void *safemalloc(size_t n
, size_t size
)
543 if (n
> INT_MAX
/ size
) {
547 if (size
== 0) size
= 1;
549 p
= minefield_c_malloc(size
);
558 sprintf(str
, "Out of memory! (%s:%d, size=%d)",
559 mlog_file
, mlog_line
, size
);
560 fprintf(fp
, "*** %s\n", str
);
563 strcpy(str
, "Out of memory!");
569 fprintf(fp
, "malloc(%d) returns %p\n", size
, p
);
574 void *saferealloc(void *ptr
, size_t n
, size_t size
)
578 if (n
> INT_MAX
/ size
) {
584 p
= minefield_c_malloc(size
);
590 p
= minefield_c_realloc(ptr
, size
);
592 p
= realloc(ptr
, size
);
600 sprintf(str
, "Out of memory! (%s:%d, size=%d)",
601 mlog_file
, mlog_line
, size
);
602 fprintf(fp
, "*** %s\n", str
);
605 strcpy(str
, "Out of memory!");
611 fprintf(fp
, "realloc(%p,%d) returns %p\n", ptr
, size
, p
);
616 void safefree(void *ptr
)
621 fprintf(fp
, "free(%p)\n", ptr
);
624 minefield_c_free(ptr
);
631 fprintf(fp
, "freeing null pointer - no action taken\n");
635 /* ----------------------------------------------------------------------
636 * Debugging routines.
640 extern void dputs(char *); /* defined in per-platform *misc.c */
642 void debug_printf(char *fmt
, ...)
648 buf
= dupvprintf(fmt
, ap
);
655 void debug_memdump(void *buf
, int len
, int L
)
658 unsigned char *p
= buf
;
662 debug_printf("\t%d (0x%x) bytes:\n", len
, len
);
663 delta
= 15 & (unsigned long int) p
;
667 for (; 0 < len
; p
+= 16, len
-= 16) {
670 debug_printf("%p: ", p
);
671 strcpy(foo
, "................"); /* sixteen dots */
672 for (i
= 0; i
< 16 && i
< len
; ++i
) {
673 if (&p
[i
] < (unsigned char *) buf
) {
674 dputs(" "); /* 3 spaces */
677 debug_printf("%c%02.2x",
678 &p
[i
] != (unsigned char *) buf
679 && i
% 4 ?
'.' : ' ', p
[i
]
681 if (p
[i
] >= ' ' && p
[i
] <= '~')
682 foo
[i
] = (char) p
[i
];
686 debug_printf("%*s%s\n", (16 - i
) * 3 + 2, "", foo
);
690 #endif /* def DEBUG */
693 * Determine whether or not a Conf represents a session which can
694 * sensibly be launched right now.
696 int conf_launchable(Conf
*conf
)
698 if (conf_get_int(conf
, CONF_protocol
) == PROT_SERIAL
)
699 return conf_get_str(conf
, CONF_serline
)[0] != 0;
701 return conf_get_str(conf
, CONF_host
)[0] != 0;
704 char const *conf_dest(Conf
*conf
)
706 if (conf_get_int(conf
, CONF_protocol
) == PROT_SERIAL
)
707 return conf_get_str(conf
, CONF_serline
);
709 return conf_get_str(conf
, CONF_host
);
712 #ifndef PLATFORM_HAS_SMEMCLR
714 * Securely wipe memory.
716 * The actual wiping is no different from what memset would do: the
717 * point of 'securely' is to try to be sure over-clever compilers
718 * won't optimise away memsets on variables that are about to be freed
719 * or go out of scope. See
720 * https://buildsecurityin.us-cert.gov/bsi-rules/home/g1/771-BSI.html
722 * Some platforms (e.g. Windows) may provide their own version of this
725 void smemclr(void *b
, size_t n
) {
730 * Zero out the memory.
735 * Perform a volatile access to the object, forcing the
736 * compiler to admit that the previous memset was important.
738 * This while loop should in practice run for zero iterations
739 * (since we know we just zeroed the object out), but in
740 * theory (as far as the compiler knows) it might range over
741 * the whole object. (If we had just written, say, '*vp =
742 * *vp;', a compiler could in principle have 'helpfully'
743 * optimised the memset into only zeroing out the first byte.
744 * This should be robust.)