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