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.)