| blob | d652b3948224ed7e71b195c8ade084a218f22568 |
1 /*\r
2 * Platform-independent routines shared between all PuTTY programs.\r
3 */\r
4 \r
5 #include <stdio.h>\r
6 #include <stdlib.h>\r
7 #include <stdarg.h>\r
8 #include <limits.h>\r
9 #include <ctype.h>\r
10 #include <assert.h>\r
11 #include "putty.h"\r
12 \r
13 /*\r
14 * Parse a string block size specification. This is approximately a\r
15 * subset of the block size specs supported by GNU fileutils:\r
16 * "nk" = n kilobytes\r
17 * "nM" = n megabytes\r
18 * "nG" = n gigabytes\r
19 * All numbers are decimal, and suffixes refer to powers of two.\r
20 * Case-insensitive.\r
21 */\r
22 unsigned long parse_blocksize(const char *bs)\r
23 {\r
24 char *suf;\r
25 unsigned long r = strtoul(bs, &suf, 10);\r
26 if (*suf != '\0') {\r
27 while (*suf && isspace((unsigned char)*suf)) suf++;\r
28 switch (*suf) {\r
29 case 'k': case 'K':\r
30 r *= 1024ul;\r
31 break;\r
32 case 'm': case 'M':\r
33 r *= 1024ul * 1024ul;\r
34 break;\r
35 case 'g': case 'G':\r
36 r *= 1024ul * 1024ul * 1024ul;\r
37 break;\r
38 case '\0':\r
39 default:\r
40 break;\r
41 }\r
42 }\r
43 return r;\r
44 }\r
45 \r
46 /*\r
47 * Parse a ^C style character specification.\r
48 * Returns NULL in `next' if we didn't recognise it as a control character,\r
49 * in which case `c' should be ignored.\r
50 * The precise current parsing is an oddity inherited from the terminal\r
51 * answerback-string parsing code. All sequences start with ^; all except\r
52 * ^<123> are two characters. The ones that are worth keeping are probably:\r
53 * ^? 127\r
54 * ^@A-Z[\]^_ 0-31\r
55 * a-z 1-26\r
56 * <num> specified by number (decimal, 0octal, 0xHEX)\r
57 * ~ ^ escape\r
58 */\r
59 char ctrlparse(char *s, char **next)\r
60 {\r
61 char c = 0;\r
62 if (*s != '^') {\r
63 *next = NULL;\r
64 } else {\r
65 s++;\r
66 if (*s == '\0') {\r
67 *next = NULL;\r
68 } else if (*s == '<') {\r
69 s++;\r
70 c = (char)strtol(s, next, 0);\r
71 if ((*next == s) || (**next != '>')) {\r
72 c = 0;\r
73 *next = NULL;\r
74 } else\r
75 (*next)++;\r
76 } else if (*s >= 'a' && *s <= 'z') {\r
77 c = (*s - ('a' - 1));\r
78 *next = s+1;\r
79 } else if ((*s >= '@' && *s <= '_') || *s == '?' || (*s & 0x80)) {\r
80 c = ('@' ^ *s);\r
81 *next = s+1;\r
82 } else if (*s == '~') {\r
83 c = '^';\r
84 *next = s+1;\r
85 }\r
86 }\r
87 return c;\r
88 }\r
89 \r
90 prompts_t *new_prompts(void *frontend)\r
91 {\r
92 prompts_t *p = snew(prompts_t);\r
93 p->prompts = NULL;\r
94 p->n_prompts = 0;\r
95 p->frontend = frontend;\r
96 p->data = NULL;\r
97 p->to_server = TRUE; /* to be on the safe side */\r
98 p->name = p->instruction = NULL;\r
99 p->name_reqd = p->instr_reqd = FALSE;\r
100 return p;\r
101 }\r
102 void add_prompt(prompts_t *p, char *promptstr, int echo)\r
103 {\r
104 prompt_t *pr = snew(prompt_t);\r
105 pr->prompt = promptstr;\r
106 pr->echo = echo;\r
107 pr->result = NULL;\r
108 pr->resultsize = 0;\r
109 p->n_prompts++;\r
110 p->prompts = sresize(p->prompts, p->n_prompts, prompt_t *);\r
111 p->prompts[p->n_prompts-1] = pr;\r
112 }\r
113 void prompt_ensure_result_size(prompt_t *pr, int newlen)\r
114 {\r
115 if ((int)pr->resultsize < newlen) {\r
116 char *newbuf;\r
117 newlen = newlen * 5 / 4 + 512; /* avoid too many small allocs */\r
118 \r
119 /*\r
120 * We don't use sresize / realloc here, because we will be\r
121 * storing sensitive stuff like passwords in here, and we want\r
122 * to make sure that the data doesn't get copied around in\r
123 * memory without the old copy being destroyed.\r
124 */\r
125 newbuf = snewn(newlen, char);\r
126 memcpy(newbuf, pr->result, pr->resultsize);\r
127 smemclr(pr->result, pr->resultsize);\r
128 sfree(pr->result);\r
129 pr->result = newbuf;\r
130 pr->resultsize = newlen;\r
131 }\r
132 }\r
133 void prompt_set_result(prompt_t *pr, const char *newstr)\r
134 {\r
135 prompt_ensure_result_size(pr, strlen(newstr) + 1);\r
136 strcpy(pr->result, newstr);\r
137 }\r
138 void free_prompts(prompts_t *p)\r
139 {\r
140 size_t i;\r
141 for (i=0; i < p->n_prompts; i++) {\r
142 prompt_t *pr = p->prompts[i];\r
143 smemclr(pr->result, pr->resultsize); /* burn the evidence */\r
144 sfree(pr->result);\r
145 sfree(pr->prompt);\r
146 sfree(pr);\r
147 }\r
148 sfree(p->prompts);\r
149 sfree(p->name);\r
150 sfree(p->instruction);\r
151 sfree(p);\r
152 }\r
153 \r
154 /* ----------------------------------------------------------------------\r
155 * String handling routines.\r
156 */\r
157 \r
158 char *dupstr(const char *s)\r
159 {\r
160 char *p = NULL;\r
161 if (s) {\r
162 int len = strlen(s);\r
163 p = snewn(len + 1, char);\r
164 strcpy(p, s);\r
165 }\r
166 return p;\r
167 }\r
168 \r
169 /* Allocate the concatenation of N strings. Terminate arg list with NULL. */\r
170 char *dupcat(const char *s1, ...)\r
171 {\r
172 int len;\r
173 char *p, *q, *sn;\r
174 va_list ap;\r
175 \r
176 len = strlen(s1);\r
177 va_start(ap, s1);\r
178 while (1) {\r
179 sn = va_arg(ap, char *);\r
180 if (!sn)\r
181 break;\r
182 len += strlen(sn);\r
183 }\r
184 va_end(ap);\r
185 \r
186 p = snewn(len + 1, char);\r
187 strcpy(p, s1);\r
188 q = p + strlen(p);\r
189 \r
190 va_start(ap, s1);\r
191 while (1) {\r
192 sn = va_arg(ap, char *);\r
193 if (!sn)\r
194 break;\r
195 strcpy(q, sn);\r
196 q += strlen(q);\r
197 }\r
198 va_end(ap);\r
199 \r
200 return p;\r
201 }\r
202 \r
203 void burnstr(char *string) /* sfree(str), only clear it first */\r
204 {\r
205 if (string) {\r
206 smemclr(string, strlen(string));\r
207 sfree(string);\r
208 }\r
209 }\r
210 \r
211 int toint(unsigned u)\r
212 {\r
213 /*\r
214 * Convert an unsigned to an int, without running into the\r
215 * undefined behaviour which happens by the strict C standard if\r
216 * the value overflows. You'd hope that sensible compilers would\r
217 * do the sensible thing in response to a cast, but actually I\r
218 * don't trust modern compilers not to do silly things like\r
219 * assuming that _obviously_ you wouldn't have caused an overflow\r
220 * and so they can elide an 'if (i < 0)' test immediately after\r
221 * the cast.\r
222 *\r
223 * Sensible compilers ought of course to optimise this entire\r
224 * function into 'just return the input value'!\r
225 */\r
226 if (u <= (unsigned)INT_MAX)\r
227 return (int)u;\r
228 else if (u >= (unsigned)INT_MIN) /* wrap in cast _to_ unsigned is OK */\r
229 return INT_MIN + (int)(u - (unsigned)INT_MIN);\r
230 else\r
231 return INT_MIN; /* fallback; should never occur on binary machines */\r
232 }\r
233 \r
234 /*\r
235 * Do an sprintf(), but into a custom-allocated buffer.\r
236 * \r
237 * Currently I'm doing this via vsnprintf. This has worked so far,\r
238 * but it's not good, because vsnprintf is not available on all\r
239 * platforms. There's an ifdef to use `_vsnprintf', which seems\r
240 * to be the local name for it on Windows. Other platforms may\r
241 * lack it completely, in which case it'll be time to rewrite\r
242 * this function in a totally different way.\r
243 * \r
244 * The only `properly' portable solution I can think of is to\r
245 * implement my own format string scanner, which figures out an\r
246 * upper bound for the length of each formatting directive,\r
247 * allocates the buffer as it goes along, and calls sprintf() to\r
248 * actually process each directive. If I ever need to actually do\r
249 * this, some caveats:\r
250 * \r
251 * - It's very hard to find a reliable upper bound for\r
252 * floating-point values. %f, in particular, when supplied with\r
253 * a number near to the upper or lower limit of representable\r
254 * numbers, could easily take several hundred characters. It's\r
255 * probably feasible to predict this statically using the\r
256 * constants in <float.h>, or even to predict it dynamically by\r
257 * looking at the exponent of the specific float provided, but\r
258 * it won't be fun.\r
259 * \r
260 * - Don't forget to _check_, after calling sprintf, that it's\r
261 * used at most the amount of space we had available.\r
262 * \r
263 * - Fault any formatting directive we don't fully understand. The\r
264 * aim here is to _guarantee_ that we never overflow the buffer,\r
265 * because this is a security-critical function. If we see a\r
266 * directive we don't know about, we should panic and die rather\r
267 * than run any risk.\r
268 */\r
269 char *dupprintf(const char *fmt, ...)\r
270 {\r
271 char *ret;\r
272 va_list ap;\r
273 va_start(ap, fmt);\r
274 ret = dupvprintf(fmt, ap);\r
275 va_end(ap);\r
276 return ret;\r
277 }\r
278 char *dupvprintf(const char *fmt, va_list ap)\r
279 {\r
280 char *buf;\r
281 int len, size;\r
282 \r
283 buf = snewn(512, char);\r
284 size = 512;\r
285 \r
286 while (1) {\r
287 #ifdef _WINDOWS\r
288 #define vsnprintf _vsnprintf\r
289 #endif\r
290 #ifdef va_copy\r
291 /* Use the `va_copy' macro mandated by C99, if present.\r
292 * XXX some environments may have this as __va_copy() */\r
293 va_list aq;\r
294 va_copy(aq, ap);\r
295 len = vsnprintf(buf, size, fmt, aq);\r
296 va_end(aq);\r
297 #else\r
298 /* Ugh. No va_copy macro, so do something nasty.\r
299 * Technically, you can't reuse a va_list like this: it is left\r
300 * unspecified whether advancing a va_list pointer modifies its\r
301 * value or something it points to, so on some platforms calling\r
302 * vsnprintf twice on the same va_list might fail hideously\r
303 * (indeed, it has been observed to).\r
304 * XXX the autoconf manual suggests that using memcpy() will give\r
305 * "maximum portability". */\r
306 len = vsnprintf(buf, size, fmt, ap);\r
307 #endif\r
308 if (len >= 0 && len < size) {\r
309 /* This is the C99-specified criterion for snprintf to have\r
310 * been completely successful. */\r
311 return buf;\r
312 } else if (len > 0) {\r
313 /* This is the C99 error condition: the returned length is\r
314 * the required buffer size not counting the NUL. */\r
315 size = len + 1;\r
316 } else {\r
317 /* This is the pre-C99 glibc error condition: <0 means the\r
318 * buffer wasn't big enough, so we enlarge it a bit and hope. */\r
319 size += 512;\r
320 }\r
321 buf = sresize(buf, size, char);\r
322 }\r
323 }\r
324 \r
325 /*\r
326 * Read an entire line of text from a file. Return a buffer\r
327 * malloced to be as big as necessary (caller must free).\r
328 */\r
329 char *fgetline(FILE *fp)\r
330 {\r
331 char *ret = snewn(512, char);\r
332 int size = 512, len = 0;\r
333 while (fgets(ret + len, size - len, fp)) {\r
334 len += strlen(ret + len);\r
335 if (ret[len-1] == '\n')\r
336 break; /* got a newline, we're done */\r
337 size = len + 512;\r
338 ret = sresize(ret, size, char);\r
339 }\r
340 if (len == 0) { /* first fgets returned NULL */\r
341 sfree(ret);\r
342 return NULL;\r
343 }\r
344 ret[len] = '\0';\r
345 return ret;\r
346 }\r
347 \r
348 /* ----------------------------------------------------------------------\r
349 * Base64 encoding routine. This is required in public-key writing\r
350 * but also in HTTP proxy handling, so it's centralised here.\r
351 */\r
352 \r
353 void base64_encode_atom(unsigned char *data, int n, char *out)\r
354 {\r
355 static const char base64_chars[] =\r
356 "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";\r
357 \r
358 unsigned word;\r
359 \r
360 word = data[0] << 16;\r
361 if (n > 1)\r
362 word |= data[1] << 8;\r
363 if (n > 2)\r
364 word |= data[2];\r
365 out[0] = base64_chars[(word >> 18) & 0x3F];\r
366 out[1] = base64_chars[(word >> 12) & 0x3F];\r
367 if (n > 1)\r
368 out[2] = base64_chars[(word >> 6) & 0x3F];\r
369 else\r
370 out[2] = '=';\r
371 if (n > 2)\r
372 out[3] = base64_chars[word & 0x3F];\r
373 else\r
374 out[3] = '=';\r
375 }\r
376 \r
377 /* ----------------------------------------------------------------------\r
378 * Generic routines to deal with send buffers: a linked list of\r
379 * smallish blocks, with the operations\r
380 * \r
381 * - add an arbitrary amount of data to the end of the list\r
382 * - remove the first N bytes from the list\r
383 * - return a (pointer,length) pair giving some initial data in\r
384 * the list, suitable for passing to a send or write system\r
385 * call\r
386 * - retrieve a larger amount of initial data from the list\r
387 * - return the current size of the buffer chain in bytes\r
388 */\r
389 \r
390 #define BUFFER_MIN_GRANULE 512\r
391 \r
392 struct bufchain_granule {\r
393 struct bufchain_granule *next;\r
394 char *bufpos, *bufend, *bufmax;\r
395 };\r
396 \r
397 void bufchain_init(bufchain *ch)\r
398 {\r
399 ch->head = ch->tail = NULL;\r
400 ch->buffersize = 0;\r
401 }\r
402 \r
403 void bufchain_clear(bufchain *ch)\r
404 {\r
405 struct bufchain_granule *b;\r
406 while (ch->head) {\r
407 b = ch->head;\r
408 ch->head = ch->head->next;\r
409 sfree(b);\r
410 }\r
411 ch->tail = NULL;\r
412 ch->buffersize = 0;\r
413 }\r
414 \r
415 int bufchain_size(bufchain *ch)\r
416 {\r
417 return ch->buffersize;\r
418 }\r
419 \r
420 void bufchain_add(bufchain *ch, const void *data, int len)\r
421 {\r
422 const char *buf = (const char *)data;\r
423 \r
424 if (len == 0) return;\r
425 \r
426 ch->buffersize += len;\r
427 \r
428 while (len > 0) {\r
429 if (ch->tail && ch->tail->bufend < ch->tail->bufmax) {\r
430 int copylen = min(len, ch->tail->bufmax - ch->tail->bufend);\r
431 memcpy(ch->tail->bufend, buf, copylen);\r
432 buf += copylen;\r
433 len -= copylen;\r
434 ch->tail->bufend += copylen;\r
435 }\r
436 if (len > 0) {\r
437 int grainlen =\r
438 max(sizeof(struct bufchain_granule) + len, BUFFER_MIN_GRANULE);\r
439 struct bufchain_granule *newbuf;\r
440 newbuf = smalloc(grainlen);\r
441 newbuf->bufpos = newbuf->bufend =\r
442 (char *)newbuf + sizeof(struct bufchain_granule);\r
443 newbuf->bufmax = (char *)newbuf + grainlen;\r
444 newbuf->next = NULL;\r
445 if (ch->tail)\r
446 ch->tail->next = newbuf;\r
447 else\r
448 ch->head = newbuf;\r
449 ch->tail = newbuf;\r
450 }\r
451 }\r
452 }\r
453 \r
454 void bufchain_consume(bufchain *ch, int len)\r
455 {\r
456 struct bufchain_granule *tmp;\r
457 \r
458 assert(ch->buffersize >= len);\r
459 while (len > 0) {\r
460 int remlen = len;\r
461 assert(ch->head != NULL);\r
462 if (remlen >= ch->head->bufend - ch->head->bufpos) {\r
463 remlen = ch->head->bufend - ch->head->bufpos;\r
464 tmp = ch->head;\r
465 ch->head = tmp->next;\r
466 if (!ch->head)\r
467 ch->tail = NULL;\r
468 sfree(tmp);\r
469 } else\r
470 ch->head->bufpos += remlen;\r
471 ch->buffersize -= remlen;\r
472 len -= remlen;\r
473 }\r
474 }\r
475 \r
476 void bufchain_prefix(bufchain *ch, void **data, int *len)\r
477 {\r
478 *len = ch->head->bufend - ch->head->bufpos;\r
479 *data = ch->head->bufpos;\r
480 }\r
481 \r
482 void bufchain_fetch(bufchain *ch, void *data, int len)\r
483 {\r
484 struct bufchain_granule *tmp;\r
485 char *data_c = (char *)data;\r
486 \r
487 tmp = ch->head;\r
488 \r
489 assert(ch->buffersize >= len);\r
490 while (len > 0) {\r
491 int remlen = len;\r
492 \r
493 assert(tmp != NULL);\r
494 if (remlen >= tmp->bufend - tmp->bufpos)\r
495 remlen = tmp->bufend - tmp->bufpos;\r
496 memcpy(data_c, tmp->bufpos, remlen);\r
497 \r
498 tmp = tmp->next;\r
499 len -= remlen;\r
500 data_c += remlen;\r
501 }\r
502 }\r
503 \r
504 /* ----------------------------------------------------------------------\r
505 * My own versions of malloc, realloc and free. Because I want\r
506 * malloc and realloc to bomb out and exit the program if they run\r
507 * out of memory, realloc to reliably call malloc if passed a NULL\r
508 * pointer, and free to reliably do nothing if passed a NULL\r
509 * pointer. We can also put trace printouts in, if we need to; and\r
510 * we can also replace the allocator with an ElectricFence-like\r
511 * one.\r
512 */\r
513 \r
514 #ifdef MINEFIELD\r
515 void *minefield_c_malloc(size_t size);\r
516 void minefield_c_free(void *p);\r
517 void *minefield_c_realloc(void *p, size_t size);\r
518 #endif\r
519 \r
520 #ifdef MALLOC_LOG\r
521 static FILE *fp = NULL;\r
522 \r
523 static char *mlog_file = NULL;\r
524 static int mlog_line = 0;\r
525 \r
526 void mlog(char *file, int line)\r
527 {\r
528 mlog_file = file;\r
529 mlog_line = line;\r
530 if (!fp) {\r
531 fp = fopen("putty_mem.log", "w");\r
532 setvbuf(fp, NULL, _IONBF, BUFSIZ);\r
533 }\r
534 if (fp)\r
535 fprintf(fp, "%s:%d: ", file, line);\r
536 }\r
537 #endif\r
538 \r
539 void *safemalloc(size_t n, size_t size)\r
540 {\r
541 void *p;\r
542 \r
543 if (n > INT_MAX / size) {\r
544 p = NULL;\r
545 } else {\r
546 size *= n;\r
547 if (size == 0) size = 1;\r
548 #ifdef MINEFIELD\r
549 p = minefield_c_malloc(size);\r
550 #else\r
551 p = malloc(size);\r
552 #endif\r
553 }\r
554 \r
555 if (!p) {\r
556 char str[200];\r
557 #ifdef MALLOC_LOG\r
558 sprintf(str, "Out of memory! (%s:%d, size=%d)",\r
559 mlog_file, mlog_line, size);\r
560 fprintf(fp, "*** %s\n", str);\r
561 fclose(fp);\r
562 #else\r
563 strcpy(str, "Out of memory!");\r
564 #endif\r
565 modalfatalbox(str);\r
566 }\r
567 #ifdef MALLOC_LOG\r
568 if (fp)\r
569 fprintf(fp, "malloc(%d) returns %p\n", size, p);\r
570 #endif\r
571 return p;\r
572 }\r
573 \r
574 void *saferealloc(void *ptr, size_t n, size_t size)\r
575 {\r
576 void *p;\r
577 \r
578 if (n > INT_MAX / size) {\r
579 p = NULL;\r
580 } else {\r
581 size *= n;\r
582 if (!ptr) {\r
583 #ifdef MINEFIELD\r
584 p = minefield_c_malloc(size);\r
585 #else\r
586 p = malloc(size);\r
587 #endif\r
588 } else {\r
589 #ifdef MINEFIELD\r
590 p = minefield_c_realloc(ptr, size);\r
591 #else\r
592 p = realloc(ptr, size);\r
593 #endif\r
594 }\r
595 }\r
596 \r
597 if (!p) {\r
598 char str[200];\r
599 #ifdef MALLOC_LOG\r
600 sprintf(str, "Out of memory! (%s:%d, size=%d)",\r
601 mlog_file, mlog_line, size);\r
602 fprintf(fp, "*** %s\n", str);\r
603 fclose(fp);\r
604 #else\r
605 strcpy(str, "Out of memory!");\r
606 #endif\r
607 modalfatalbox(str);\r
608 }\r
609 #ifdef MALLOC_LOG\r
610 if (fp)\r
611 fprintf(fp, "realloc(%p,%d) returns %p\n", ptr, size, p);\r
612 #endif\r
613 return p;\r
614 }\r
615 \r
616 void safefree(void *ptr)\r
617 {\r
618 if (ptr) {\r
619 #ifdef MALLOC_LOG\r
620 if (fp)\r
621 fprintf(fp, "free(%p)\n", ptr);\r
622 #endif\r
623 #ifdef MINEFIELD\r
624 minefield_c_free(ptr);\r
625 #else\r
626 free(ptr);\r
627 #endif\r
628 }\r
629 #ifdef MALLOC_LOG\r
630 else if (fp)\r
631 fprintf(fp, "freeing null pointer - no action taken\n");\r
632 #endif\r
633 }\r
634 \r
635 /* ----------------------------------------------------------------------\r
636 * Debugging routines.\r
637 */\r
638 \r
639 #ifdef DEBUG\r
640 extern void dputs(char *); /* defined in per-platform *misc.c */\r
641 \r
642 void debug_printf(char *fmt, ...)\r
643 {\r
644 char *buf;\r
645 va_list ap;\r
646 \r
647 va_start(ap, fmt);\r
648 buf = dupvprintf(fmt, ap);\r
649 dputs(buf);\r
650 sfree(buf);\r
651 va_end(ap);\r
652 }\r
653 \r
654 \r
655 void debug_memdump(void *buf, int len, int L)\r
656 {\r
657 int i;\r
658 unsigned char *p = buf;\r
659 char foo[17];\r
660 if (L) {\r
661 int delta;\r
662 debug_printf("\t%d (0x%x) bytes:\n", len, len);\r
663 delta = 15 & (unsigned long int) p;\r
664 p -= delta;\r
665 len += delta;\r
666 }\r
667 for (; 0 < len; p += 16, len -= 16) {\r
668 dputs(" ");\r
669 if (L)\r
670 debug_printf("%p: ", p);\r
671 strcpy(foo, "................"); /* sixteen dots */\r
672 for (i = 0; i < 16 && i < len; ++i) {\r
673 if (&p[i] < (unsigned char *) buf) {\r
674 dputs(" "); /* 3 spaces */\r
675 foo[i] = ' ';\r
676 } else {\r
677 debug_printf("%c%02.2x",\r
678 &p[i] != (unsigned char *) buf\r
679 && i % 4 ? '.' : ' ', p[i]\r
680 );\r
681 if (p[i] >= ' ' && p[i] <= '~')\r
682 foo[i] = (char) p[i];\r
683 }\r
684 }\r
685 foo[i] = '\0';\r
686 debug_printf("%*s%s\n", (16 - i) * 3 + 2, "", foo);\r
687 }\r
688 }\r
689 \r
690 #endif /* def DEBUG */\r
691 \r
692 /*\r
693 * Determine whether or not a Conf represents a session which can\r
694 * sensibly be launched right now.\r
695 */\r
696 int conf_launchable(Conf *conf)\r
697 {\r
698 if (conf_get_int(conf, CONF_protocol) == PROT_SERIAL)\r
699 return conf_get_str(conf, CONF_serline)[0] != 0;\r
700 else\r
701 return conf_get_str(conf, CONF_host)[0] != 0;\r
702 }\r
703 \r
704 char const *conf_dest(Conf *conf)\r
705 {\r
706 if (conf_get_int(conf, CONF_protocol) == PROT_SERIAL)\r
707 return conf_get_str(conf, CONF_serline);\r
708 else\r
709 return conf_get_str(conf, CONF_host);\r
710 }\r
711 \r
712 #ifndef PLATFORM_HAS_SMEMCLR\r
713 /*\r
714 * Securely wipe memory.\r
715 *\r
716 * The actual wiping is no different from what memset would do: the\r
717 * point of 'securely' is to try to be sure over-clever compilers\r
718 * won't optimise away memsets on variables that are about to be freed\r
719 * or go out of scope. See\r
720 * https://buildsecurityin.us-cert.gov/bsi-rules/home/g1/771-BSI.html\r
721 *\r
722 * Some platforms (e.g. Windows) may provide their own version of this\r
723 * function.\r
724 */\r
725 void smemclr(void *b, size_t n) {\r
726 volatile char *vp;\r
727 \r
728 if (b && n > 0) {\r
729 /*\r
730 * Zero out the memory.\r
731 */\r
732 memset(b, 0, n);\r
733 \r
734 /*\r
735 * Perform a volatile access to the object, forcing the\r
736 * compiler to admit that the previous memset was important.\r
737 *\r
738 * This while loop should in practice run for zero iterations\r
739 * (since we know we just zeroed the object out), but in\r
740 * theory (as far as the compiler knows) it might range over\r
741 * the whole object. (If we had just written, say, '*vp =\r
742 * *vp;', a compiler could in principle have 'helpfully'\r
743 * optimised the memset into only zeroing out the first byte.\r
744 * This should be robust.)\r
745 */\r
746 vp = b;\r
747 while (*vp) vp++;\r
748 }\r
749 }\r
750 #endif\r