git.distorted.org.uk Git - u/mdw/putty/blob - windows/winstore.c

   1 /*
   2  * winstore.c: Windows-specific implementation of the interface
   3  * defined in storage.h.
   4  */
   5
   6 #include <stdio.h>
   7 #include <stdlib.h>
   8 #include <limits.h>
   9 #include "putty.h"
  10 #include "storage.h"
  11
  12 #include <shlobj.h>
  13 #ifndef CSIDL_APPDATA
  14 #define CSIDL_APPDATA 0x001a
  15 #endif
  16 #ifndef CSIDL_LOCAL_APPDATA
  17 #define CSIDL_LOCAL_APPDATA 0x001c
  18 #endif
  19
  20 static const char *const reg_jumplist_key = PUTTY_REG_POS "\\Jumplist";
  21 static const char *const reg_jumplist_value = "Recent sessions";
  22 static const char *const puttystr = PUTTY_REG_POS "\\Sessions";
  23
  24 static const char hex[16] = "0123456789ABCDEF";
  25
  26 static int tried_shgetfolderpath = FALSE;
  27 static HMODULE shell32_module = NULL;
  28 DECL_WINDOWS_FUNCTION(static, HRESULT, SHGetFolderPathA,
  29                       (HWND, int, HANDLE, DWORD, LPSTR));
  30
  31 static void mungestr(const char *in, char *out)
  32 {
  33     int candot = 0;
  34
  35     while (*in) {
  36         if (*in == ' ' || *in == '\\' || *in == '*' || *in == '?' ||
  37             *in == '%' || *in < ' ' || *in > '~' || (*in == '.'
  38                                                      && !candot)) {
  39             *out++ = '%';
  40             *out++ = hex[((unsigned char) *in) >> 4];
  41             *out++ = hex[((unsigned char) *in) & 15];
  42         } else
  43             *out++ = *in;
  44         in++;
  45         candot = 1;
  46     }
  47     *out = '\0';
  48     return;
  49 }
  50
  51 static void unmungestr(const char *in, char *out, int outlen)
  52 {
  53     while (*in) {
  54         if (*in == '%' && in[1] && in[2]) {
  55             int i, j;
  56
  57             i = in[1] - '0';
  58             i -= (i > 9 ? 7 : 0);
  59             j = in[2] - '0';
  60             j -= (j > 9 ? 7 : 0);
  61
  62             *out++ = (i << 4) + j;
  63             if (!--outlen)
  64                 return;
  65             in += 3;
  66         } else {
  67             *out++ = *in++;
  68             if (!--outlen)
  69                 return;
  70         }
  71     }
  72     *out = '\0';
  73     return;
  74 }
  75
  76 void *open_settings_w(const char *sessionname, char **errmsg)
  77 {
  78     HKEY subkey1, sesskey;
  79     int ret;
  80     char *p;
  81
  82     *errmsg = NULL;
  83
  84     if (!sessionname || !*sessionname)
  85         sessionname = "Default Settings";
  86
  87     p = snewn(3 * strlen(sessionname) + 1, char);
  88     mungestr(sessionname, p);
  89
  90     ret = RegCreateKey(HKEY_CURRENT_USER, puttystr, &subkey1);
  91     if (ret != ERROR_SUCCESS) {
  92         sfree(p);
  93         *errmsg = dupprintf("Unable to create registry key\n"
  94                             "HKEY_CURRENT_USER\\%s", puttystr);
  95         return NULL;
  96     }
  97     ret = RegCreateKey(subkey1, p, &sesskey);
  98     RegCloseKey(subkey1);
  99     if (ret != ERROR_SUCCESS) {
 100         *errmsg = dupprintf("Unable to create registry key\n"
 101                             "HKEY_CURRENT_USER\\%s\\%s", puttystr, p);
 102         sfree(p);
 103         return NULL;
 104     }
 105     sfree(p);
 106     return (void *) sesskey;
 107 }
 108
 109 void write_setting_s(void *handle, const char *key, const char *value)
 110 {
 111     if (handle)
 112         RegSetValueEx((HKEY) handle, key, 0, REG_SZ, value,
 113                       1 + strlen(value));
 114 }
 115
 116 void write_setting_i(void *handle, const char *key, int value)
 117 {
 118     if (handle)
 119         RegSetValueEx((HKEY) handle, key, 0, REG_DWORD,
 120                       (CONST BYTE *) &value, sizeof(value));
 121 }
 122
 123 void close_settings_w(void *handle)
 124 {
 125     RegCloseKey((HKEY) handle);
 126 }
 127
 128 void *open_settings_r(const char *sessionname)
 129 {
 130     HKEY subkey1, sesskey;
 131     char *p;
 132
 133     if (!sessionname || !*sessionname)
 134         sessionname = "Default Settings";
 135
 136     p = snewn(3 * strlen(sessionname) + 1, char);
 137     mungestr(sessionname, p);
 138
 139     if (RegOpenKey(HKEY_CURRENT_USER, puttystr, &subkey1) != ERROR_SUCCESS) {
 140         sesskey = NULL;
 141     } else {
 142         if (RegOpenKey(subkey1, p, &sesskey) != ERROR_SUCCESS) {
 143             sesskey = NULL;
 144         }
 145         RegCloseKey(subkey1);
 146     }
 147
 148     sfree(p);
 149
 150     return (void *) sesskey;
 151 }
 152
 153 char *read_setting_s(void *handle, const char *key)
 154 {
 155     DWORD type, size;
 156     char *ret;
 157
 158     if (!handle)
 159         return NULL;
 160
 161     /* Find out the type and size of the data. */
 162     if (RegQueryValueEx((HKEY) handle, key, 0,
 163                         &type, NULL, &size) != ERROR_SUCCESS ||
 164         type != REG_SZ)
 165         return NULL;
 166
 167     ret = snewn(size+1, char);
 168     if (RegQueryValueEx((HKEY) handle, key, 0,
 169                         &type, ret, &size) != ERROR_SUCCESS ||
 170         type != REG_SZ) return NULL;
 171
 172     return ret;
 173 }
 174
 175 int read_setting_i(void *handle, const char *key, int defvalue)
 176 {
 177     DWORD type, val, size;
 178     size = sizeof(val);
 179
 180     if (!handle ||
 181         RegQueryValueEx((HKEY) handle, key, 0, &type,
 182                         (BYTE *) &val, &size) != ERROR_SUCCESS ||
 183         size != sizeof(val) || type != REG_DWORD)
 184         return defvalue;
 185     else
 186         return val;
 187 }
 188
 189 FontSpec *read_setting_fontspec(void *handle, const char *name)
 190 {
 191     char *settingname;
 192     char *fontname;
 193     int isbold, height, charset;
 194
 195     fontname = read_setting_s(handle, name);
 196     if (!fontname)
 197         return NULL;
 198
 199     settingname = dupcat(name, "IsBold", NULL);
 200     isbold = read_setting_i(handle, settingname, -1);
 201     sfree(settingname);
 202     if (isbold == -1) return NULL;
 203
 204     settingname = dupcat(name, "CharSet", NULL);
 205     charset = read_setting_i(handle, settingname, -1);
 206     sfree(settingname);
 207     if (charset == -1) return NULL;
 208
 209     settingname = dupcat(name, "Height", NULL);
 210     height = read_setting_i(handle, settingname, INT_MIN);
 211     sfree(settingname);
 212     if (height == INT_MIN) return NULL;
 213
 214     return fontspec_new(fontname, isbold, height, charset);
 215 }
 216
 217 void write_setting_fontspec(void *handle, const char *name, FontSpec *font)
 218 {
 219     char *settingname;
 220
 221     write_setting_s(handle, name, font->name);
 222     settingname = dupcat(name, "IsBold", NULL);
 223     write_setting_i(handle, settingname, font->isbold);
 224     sfree(settingname);
 225     settingname = dupcat(name, "CharSet", NULL);
 226     write_setting_i(handle, settingname, font->charset);
 227     sfree(settingname);
 228     settingname = dupcat(name, "Height", NULL);
 229     write_setting_i(handle, settingname, font->height);
 230     sfree(settingname);
 231 }
 232
 233 Filename *read_setting_filename(void *handle, const char *name)
 234 {
 235     char *tmp = read_setting_s(handle, name);
 236     if (tmp) {
 237         Filename *ret = filename_from_str(tmp);
 238         sfree(tmp);
 239         return ret;
 240     } else
 241         return NULL;
 242 }
 243
 244 void write_setting_filename(void *handle, const char *name, Filename *result)
 245 {
 246     write_setting_s(handle, name, result->path);
 247 }
 248
 249 void close_settings_r(void *handle)
 250 {
 251     RegCloseKey((HKEY) handle);
 252 }
 253
 254 void del_settings(const char *sessionname)
 255 {
 256     HKEY subkey1;
 257     char *p;
 258
 259     if (RegOpenKey(HKEY_CURRENT_USER, puttystr, &subkey1) != ERROR_SUCCESS)
 260         return;
 261
 262     p = snewn(3 * strlen(sessionname) + 1, char);
 263     mungestr(sessionname, p);
 264     RegDeleteKey(subkey1, p);
 265     sfree(p);
 266
 267     RegCloseKey(subkey1);
 268
 269     remove_session_from_jumplist(sessionname);
 270 }
 271
 272 struct enumsettings {
 273     HKEY key;
 274     int i;
 275 };
 276
 277 void *enum_settings_start(void)
 278 {
 279     struct enumsettings *ret;
 280     HKEY key;
 281
 282     if (RegOpenKey(HKEY_CURRENT_USER, puttystr, &key) != ERROR_SUCCESS)
 283         return NULL;
 284
 285     ret = snew(struct enumsettings);
 286     if (ret) {
 287         ret->key = key;
 288         ret->i = 0;
 289     }
 290
 291     return ret;
 292 }
 293
 294 char *enum_settings_next(void *handle, char *buffer, int buflen)
 295 {
 296     struct enumsettings *e = (struct enumsettings *) handle;
 297     char *otherbuf;
 298     otherbuf = snewn(3 * buflen, char);
 299     if (RegEnumKey(e->key, e->i++, otherbuf, 3 * buflen) == ERROR_SUCCESS) {
 300         unmungestr(otherbuf, buffer, buflen);
 301         sfree(otherbuf);
 302         return buffer;
 303     } else {
 304         sfree(otherbuf);
 305         return NULL;
 306     }
 307 }
 308
 309 void enum_settings_finish(void *handle)
 310 {
 311     struct enumsettings *e = (struct enumsettings *) handle;
 312     RegCloseKey(e->key);
 313     sfree(e);
 314 }
 315
 316 static void hostkey_regname(char *buffer, const char *hostname,
 317                             int port, const char *keytype)
 318 {
 319     int len;
 320     strcpy(buffer, keytype);
 321     strcat(buffer, "@");
 322     len = strlen(buffer);
 323     len += sprintf(buffer + len, "%d:", port);
 324     mungestr(hostname, buffer + strlen(buffer));
 325 }
 326
 327 int verify_host_key(const char *hostname, int port,
 328                     const char *keytype, const char *key)
 329 {
 330     char *otherstr, *regname;
 331     int len;
 332     HKEY rkey;
 333     DWORD readlen;
 334     DWORD type;
 335     int ret, compare;
 336
 337     len = 1 + strlen(key);
 338
 339     /*
 340      * Now read a saved key in from the registry and see what it
 341      * says.
 342      */
 343     otherstr = snewn(len, char);
 344     regname = snewn(3 * (strlen(hostname) + strlen(keytype)) + 15, char);
 345
 346     hostkey_regname(regname, hostname, port, keytype);
 347
 348     if (RegOpenKey(HKEY_CURRENT_USER, PUTTY_REG_POS "\\SshHostKeys",
 349                    &rkey) != ERROR_SUCCESS)
 350         return 1;                      /* key does not exist in registry */
 351
 352     readlen = len;
 353     ret = RegQueryValueEx(rkey, regname, NULL, &type, otherstr, &readlen);
 354
 355     if (ret != ERROR_SUCCESS && ret != ERROR_MORE_DATA &&
 356         !strcmp(keytype, "rsa")) {
 357         /*
 358          * Key didn't exist. If the key type is RSA, we'll try
 359          * another trick, which is to look up the _old_ key format
 360          * under just the hostname and translate that.
 361          */
 362         char *justhost = regname + 1 + strcspn(regname, ":");
 363         char *oldstyle = snewn(len + 10, char); /* safety margin */
 364         readlen = len;
 365         ret = RegQueryValueEx(rkey, justhost, NULL, &type,
 366                               oldstyle, &readlen);
 367
 368         if (ret == ERROR_SUCCESS && type == REG_SZ) {
 369             /*
 370              * The old format is two old-style bignums separated by
 371              * a slash. An old-style bignum is made of groups of
 372              * four hex digits: digits are ordered in sensible
 373              * (most to least significant) order within each group,
 374              * but groups are ordered in silly (least to most)
 375              * order within the bignum. The new format is two
 376              * ordinary C-format hex numbers (0xABCDEFG...XYZ, with
 377              * A nonzero except in the special case 0x0, which
 378              * doesn't appear anyway in RSA keys) separated by a
 379              * comma. All hex digits are lowercase in both formats.
 380              */
 381             char *p = otherstr;
 382             char *q = oldstyle;
 383             int i, j;
 384
 385             for (i = 0; i < 2; i++) {
 386                 int ndigits, nwords;
 387                 *p++ = '0';
 388                 *p++ = 'x';
 389                 ndigits = strcspn(q, "/");      /* find / or end of string */
 390                 nwords = ndigits / 4;
 391                 /* now trim ndigits to remove leading zeros */
 392                 while (q[(ndigits - 1) ^ 3] == '0' && ndigits > 1)
 393                     ndigits--;
 394                 /* now move digits over to new string */
 395                 for (j = 0; j < ndigits; j++)
 396                     p[ndigits - 1 - j] = q[j ^ 3];
 397                 p += ndigits;
 398                 q += nwords * 4;
 399                 if (*q) {
 400                     q++;               /* eat the slash */
 401                     *p++ = ',';        /* add a comma */
 402                 }
 403                 *p = '\0';             /* terminate the string */
 404             }
 405
 406             /*
 407              * Now _if_ this key matches, we'll enter it in the new
 408              * format. If not, we'll assume something odd went
 409              * wrong, and hyper-cautiously do nothing.
 410              */
 411             if (!strcmp(otherstr, key))
 412                 RegSetValueEx(rkey, regname, 0, REG_SZ, otherstr,
 413                               strlen(otherstr) + 1);
 414         }
 415     }
 416
 417     RegCloseKey(rkey);
 418
 419     compare = strcmp(otherstr, key);
 420
 421     sfree(otherstr);
 422     sfree(regname);
 423
 424     if (ret == ERROR_MORE_DATA ||
 425         (ret == ERROR_SUCCESS && type == REG_SZ && compare))
 426         return 2;                      /* key is different in registry */
 427     else if (ret != ERROR_SUCCESS || type != REG_SZ)
 428         return 1;                      /* key does not exist in registry */
 429     else
 430         return 0;                      /* key matched OK in registry */
 431 }
 432
 433 void store_host_key(const char *hostname, int port,
 434                     const char *keytype, const char *key)
 435 {
 436     char *regname;
 437     HKEY rkey;
 438
 439     regname = snewn(3 * (strlen(hostname) + strlen(keytype)) + 15, char);
 440
 441     hostkey_regname(regname, hostname, port, keytype);
 442
 443     if (RegCreateKey(HKEY_CURRENT_USER, PUTTY_REG_POS "\\SshHostKeys",
 444                      &rkey) == ERROR_SUCCESS) {
 445         RegSetValueEx(rkey, regname, 0, REG_SZ, key, strlen(key) + 1);
 446         RegCloseKey(rkey);
 447     } /* else key does not exist in registry */
 448
 449     sfree(regname);
 450 }
 451
 452 /*
 453  * Open (or delete) the random seed file.
 454  */
 455 enum { DEL, OPEN_R, OPEN_W };
 456 static int try_random_seed(char const *path, int action, HANDLE *ret)
 457 {
 458     if (action == DEL) {
 459         if (!DeleteFile(path) && GetLastError() != ERROR_FILE_NOT_FOUND) {
 460             nonfatal("Unable to delete '%s': %s", path,
 461                      win_strerror(GetLastError()));
 462         }
 463         *ret = INVALID_HANDLE_VALUE;
 464         return FALSE;                  /* so we'll do the next ones too */
 465     }
 466
 467     *ret = CreateFile(path,
 468                       action == OPEN_W ? GENERIC_WRITE : GENERIC_READ,
 469                       action == OPEN_W ? 0 : (FILE_SHARE_READ |
 470                                               FILE_SHARE_WRITE),
 471                       NULL,
 472                       action == OPEN_W ? CREATE_ALWAYS : OPEN_EXISTING,
 473                       action == OPEN_W ? FILE_ATTRIBUTE_NORMAL : 0,
 474                       NULL);
 475
 476     return (*ret != INVALID_HANDLE_VALUE);
 477 }
 478
 479 static HANDLE access_random_seed(int action)
 480 {
 481     HKEY rkey;
 482     DWORD type, size;
 483     HANDLE rethandle;
 484     char seedpath[2 * MAX_PATH + 10] = "\0";
 485
 486     /*
 487      * Iterate over a selection of possible random seed paths until
 488      * we find one that works.
 489      *
 490      * We do this iteration separately for reading and writing,
 491      * meaning that we will automatically migrate random seed files
 492      * if a better location becomes available (by reading from the
 493      * best location in which we actually find one, and then
 494      * writing to the best location in which we can _create_ one).
 495      */
 496
 497     /*
 498      * First, try the location specified by the user in the
 499      * Registry, if any.
 500      */
 501     size = sizeof(seedpath);
 502     if (RegOpenKey(HKEY_CURRENT_USER, PUTTY_REG_POS, &rkey) ==
 503         ERROR_SUCCESS) {
 504         int ret = RegQueryValueEx(rkey, "RandSeedFile",
 505                                   0, &type, seedpath, &size);
 506         if (ret != ERROR_SUCCESS || type != REG_SZ)
 507             seedpath[0] = '\0';
 508         RegCloseKey(rkey);
 509
 510         if (*seedpath && try_random_seed(seedpath, action, &rethandle))
 511             return rethandle;
 512     }
 513
 514     /*
 515      * Next, try the user's local Application Data directory,
 516      * followed by their non-local one. This is found using the
 517      * SHGetFolderPath function, which won't be present on all
 518      * versions of Windows.
 519      */
 520     if (!tried_shgetfolderpath) {
 521         /* This is likely only to bear fruit on systems with IE5+
 522          * installed, or WinMe/2K+. There is some faffing with
 523          * SHFOLDER.DLL we could do to try to find an equivalent
 524          * on older versions of Windows if we cared enough.
 525          * However, the invocation below requires IE5+ anyway,
 526          * so stuff that. */
 527         shell32_module = load_system32_dll("shell32.dll");
 528         GET_WINDOWS_FUNCTION(shell32_module, SHGetFolderPathA);
 529         tried_shgetfolderpath = TRUE;
 530     }
 531     if (p_SHGetFolderPathA) {
 532         if (SUCCEEDED(p_SHGetFolderPathA(NULL, CSIDL_LOCAL_APPDATA,
 533                                          NULL, SHGFP_TYPE_CURRENT, seedpath))) {
 534             strcat(seedpath, "\\PUTTY.RND");
 535             if (try_random_seed(seedpath, action, &rethandle))
 536                 return rethandle;
 537         }
 538
 539         if (SUCCEEDED(p_SHGetFolderPathA(NULL, CSIDL_APPDATA,
 540                                          NULL, SHGFP_TYPE_CURRENT, seedpath))) {
 541             strcat(seedpath, "\\PUTTY.RND");
 542             if (try_random_seed(seedpath, action, &rethandle))
 543                 return rethandle;
 544         }
 545     }
 546
 547     /*
 548      * Failing that, try %HOMEDRIVE%%HOMEPATH% as a guess at the
 549      * user's home directory.
 550      */
 551     {
 552         int len, ret;
 553
 554         len =
 555             GetEnvironmentVariable("HOMEDRIVE", seedpath,
 556                                    sizeof(seedpath));
 557         ret =
 558             GetEnvironmentVariable("HOMEPATH", seedpath + len,
 559                                    sizeof(seedpath) - len);
 560         if (ret != 0) {
 561             strcat(seedpath, "\\PUTTY.RND");
 562             if (try_random_seed(seedpath, action, &rethandle))
 563                 return rethandle;
 564         }
 565     }
 566
 567     /*
 568      * And finally, fall back to C:\WINDOWS.
 569      */
 570     GetWindowsDirectory(seedpath, sizeof(seedpath));
 571     strcat(seedpath, "\\PUTTY.RND");
 572     if (try_random_seed(seedpath, action, &rethandle))
 573         return rethandle;
 574
 575     /*
 576      * If even that failed, give up.
 577      */
 578     return INVALID_HANDLE_VALUE;
 579 }
 580
 581 void read_random_seed(noise_consumer_t consumer)
 582 {
 583     HANDLE seedf = access_random_seed(OPEN_R);
 584
 585     if (seedf != INVALID_HANDLE_VALUE) {
 586         while (1) {
 587             char buf[1024];
 588             DWORD len;
 589
 590             if (ReadFile(seedf, buf, sizeof(buf), &len, NULL) && len)
 591                 consumer(buf, len);
 592             else
 593                 break;
 594         }
 595         CloseHandle(seedf);
 596     }
 597 }
 598
 599 void write_random_seed(void *data, int len)
 600 {
 601     HANDLE seedf = access_random_seed(OPEN_W);
 602
 603     if (seedf != INVALID_HANDLE_VALUE) {
 604         DWORD lenwritten;
 605
 606         WriteFile(seedf, data, len, &lenwritten, NULL);
 607         CloseHandle(seedf);
 608     }
 609 }
 610
 611 /*
 612  * Internal function supporting the jump list registry code. All the
 613  * functions to add, remove and read the list have substantially
 614  * similar content, so this is a generalisation of all of them which
 615  * transforms the list in the registry by prepending 'add' (if
 616  * non-null), removing 'rem' from what's left (if non-null), and
 617  * returning the resulting concatenated list of strings in 'out' (if
 618  * non-null).
 619  */
 620 static int transform_jumplist_registry
 621     (const char *add, const char *rem, char **out)
 622 {
 623     int ret;
 624     HKEY pjumplist_key, psettings_tmp;
 625     DWORD type;
 626     int value_length;
 627     char *old_value, *new_value;
 628     char *piterator_old, *piterator_new, *piterator_tmp;
 629
 630     ret = RegCreateKeyEx(HKEY_CURRENT_USER, reg_jumplist_key, 0, NULL,
 631                          REG_OPTION_NON_VOLATILE, (KEY_READ | KEY_WRITE), NULL,
 632                          &pjumplist_key, NULL);
 633     if (ret != ERROR_SUCCESS) {
 634         return JUMPLISTREG_ERROR_KEYOPENCREATE_FAILURE;
 635     }
 636
 637     /* Get current list of saved sessions in the registry. */
 638     value_length = 200;
 639     old_value = snewn(value_length, char);
 640     ret = RegQueryValueEx(pjumplist_key, reg_jumplist_value, NULL, &type,
 641                           old_value, &value_length);
 642     /* When the passed buffer is too small, ERROR_MORE_DATA is
 643      * returned and the required size is returned in the length
 644      * argument. */
 645     if (ret == ERROR_MORE_DATA) {
 646         sfree(old_value);
 647         old_value = snewn(value_length, char);
 648         ret = RegQueryValueEx(pjumplist_key, reg_jumplist_value, NULL, &type,
 649                               old_value, &value_length);
 650     }
 651
 652     if (ret == ERROR_FILE_NOT_FOUND) {
 653         /* Value doesn't exist yet. Start from an empty value. */
 654         *old_value = '\0';
 655         *(old_value + 1) = '\0';
 656     } else if (ret != ERROR_SUCCESS) {
 657         /* Some non-recoverable error occurred. */
 658         sfree(old_value);
 659         RegCloseKey(pjumplist_key);
 660         return JUMPLISTREG_ERROR_VALUEREAD_FAILURE;
 661     } else if (type != REG_MULTI_SZ) {
 662         /* The value present in the registry has the wrong type: we
 663          * try to delete it and start from an empty value. */
 664         ret = RegDeleteValue(pjumplist_key, reg_jumplist_value);
 665         if (ret != ERROR_SUCCESS) {
 666             sfree(old_value);
 667             RegCloseKey(pjumplist_key);
 668             return JUMPLISTREG_ERROR_VALUEREAD_FAILURE;
 669         }
 670
 671         *old_value = '\0';
 672         *(old_value + 1) = '\0';
 673     }
 674
 675     /* Check validity of registry data: REG_MULTI_SZ value must end
 676      * with \0\0. */
 677     piterator_tmp = old_value;
 678     while (((piterator_tmp - old_value) < (value_length - 1)) &&
 679            !(*piterator_tmp == '\0' && *(piterator_tmp+1) == '\0')) {
 680         ++piterator_tmp;
 681     }
 682
 683     if ((piterator_tmp - old_value) >= (value_length-1)) {
 684         /* Invalid value. Start from an empty value. */
 685         *old_value = '\0';
 686         *(old_value + 1) = '\0';
 687     }
 688
 689     /*
 690      * Modify the list, if we're modifying.
 691      */
 692     if (add || rem) {
 693         /* Walk through the existing list and construct the new list of
 694          * saved sessions. */
 695         new_value = snewn(value_length + (add ? strlen(add) + 1 : 0), char);
 696         piterator_new = new_value;
 697         piterator_old = old_value;
 698
 699         /* First add the new item to the beginning of the list. */
 700         if (add) {
 701             strcpy(piterator_new, add);
 702             piterator_new += strlen(piterator_new) + 1;
 703         }
 704         /* Now add the existing list, taking care to leave out the removed
 705          * item, if it was already in the existing list. */
 706         while (*piterator_old != '\0') {
 707             if (!rem || strcmp(piterator_old, rem) != 0) {
 708                 /* Check if this is a valid session, otherwise don't add. */
 709                 psettings_tmp = open_settings_r(piterator_old);
 710                 if (psettings_tmp != NULL) {
 711                     close_settings_r(psettings_tmp);
 712                     strcpy(piterator_new, piterator_old);
 713                     piterator_new += strlen(piterator_new) + 1;
 714                 }
 715             }
 716             piterator_old += strlen(piterator_old) + 1;
 717         }
 718         *piterator_new = '\0';
 719         ++piterator_new;
 720
 721         /* Save the new list to the registry. */
 722         ret = RegSetValueEx(pjumplist_key, reg_jumplist_value, 0, REG_MULTI_SZ,
 723                             new_value, piterator_new - new_value);
 724
 725         sfree(old_value);
 726         old_value = new_value;
 727     } else
 728         ret = ERROR_SUCCESS;
 729
 730     /*
 731      * Either return or free the result.
 732      */
 733     if (out)
 734         *out = old_value;
 735     else
 736         sfree(old_value);
 737
 738     /* Clean up and return. */
 739     RegCloseKey(pjumplist_key);
 740
 741     if (ret != ERROR_SUCCESS) {
 742         return JUMPLISTREG_ERROR_VALUEWRITE_FAILURE;
 743     } else {
 744         return JUMPLISTREG_OK;
 745     }
 746 }
 747
 748 /* Adds a new entry to the jumplist entries in the registry. */
 749 int add_to_jumplist_registry(const char *item)
 750 {
 751     return transform_jumplist_registry(item, item, NULL);
 752 }
 753
 754 /* Removes an item from the jumplist entries in the registry. */
 755 int remove_from_jumplist_registry(const char *item)
 756 {
 757     return transform_jumplist_registry(NULL, item, NULL);
 758 }
 759
 760 /* Returns the jumplist entries from the registry. Caller must free
 761  * the returned pointer. */
 762 char *get_jumplist_registry_entries (void)
 763 {
 764     char *list_value;
 765
 766     if (transform_jumplist_registry(NULL,NULL,&list_value) != ERROR_SUCCESS) {
 767         list_value = snewn(2, char);
 768         *list_value = '\0';
 769         *(list_value + 1) = '\0';
 770     }
 771     return list_value;
 772 }
 773
 774 /*
 775  * Recursively delete a registry key and everything under it.
 776  */
 777 static void registry_recursive_remove(HKEY key)
 778 {
 779     DWORD i;
 780     char name[MAX_PATH + 1];
 781     HKEY subkey;
 782
 783     i = 0;
 784     while (RegEnumKey(key, i, name, sizeof(name)) == ERROR_SUCCESS) {
 785         if (RegOpenKey(key, name, &subkey) == ERROR_SUCCESS) {
 786             registry_recursive_remove(subkey);
 787             RegCloseKey(subkey);
 788         }
 789         RegDeleteKey(key, name);
 790     }
 791 }
 792
 793 void cleanup_all(void)
 794 {
 795     HKEY key;
 796     int ret;
 797     char name[MAX_PATH + 1];
 798
 799     /* ------------------------------------------------------------
 800      * Wipe out the random seed file, in all of its possible
 801      * locations.
 802      */
 803     access_random_seed(DEL);
 804
 805     /* ------------------------------------------------------------
 806      * Ask Windows to delete any jump list information associated
 807      * with this installation of PuTTY.
 808      */
 809     clear_jumplist();
 810
 811     /* ------------------------------------------------------------
 812      * Destroy all registry information associated with PuTTY.
 813      */
 814
 815     /*
 816      * Open the main PuTTY registry key and remove everything in it.
 817      */
 818     if (RegOpenKey(HKEY_CURRENT_USER, PUTTY_REG_POS, &key) ==
 819         ERROR_SUCCESS) {
 820         registry_recursive_remove(key);
 821         RegCloseKey(key);
 822     }
 823     /*
 824      * Now open the parent key and remove the PuTTY main key. Once
 825      * we've done that, see if the parent key has any other
 826      * children.
 827      */
 828     if (RegOpenKey(HKEY_CURRENT_USER, PUTTY_REG_PARENT,
 829                    &key) == ERROR_SUCCESS) {
 830         RegDeleteKey(key, PUTTY_REG_PARENT_CHILD);
 831         ret = RegEnumKey(key, 0, name, sizeof(name));
 832         RegCloseKey(key);
 833         /*
 834          * If the parent key had no other children, we must delete
 835          * it in its turn. That means opening the _grandparent_
 836          * key.
 837          */
 838         if (ret != ERROR_SUCCESS) {
 839             if (RegOpenKey(HKEY_CURRENT_USER, PUTTY_REG_GPARENT,
 840                            &key) == ERROR_SUCCESS) {
 841                 RegDeleteKey(key, PUTTY_REG_GPARENT_CHILD);
 842                 RegCloseKey(key);
 843             }
 844         }
 845     }
 846     /*
 847      * Now we're done.
 848      */
 849 }