compat/mingw.c

   1 #include "../git-compat-util.h"
   2 #include "../strbuf.h"
   3
   4 unsigned int _CRT_fmode = _O_BINARY;
   5
   6 #undef open
   7 int mingw_open (const char *filename, int oflags, ...)
   8 {
   9         va_list args;
  10         unsigned mode;
  11         va_start(args, oflags);
  12         mode = va_arg(args, int);
  13         va_end(args);
  14
  15         if (!strcmp(filename, "/dev/null"))
  16                 filename = "nul";
  17         int fd = open(filename, oflags, mode);
  18         if (fd < 0 && (oflags & O_CREAT) && errno == EACCES) {
  19                 DWORD attrs = GetFileAttributes(filename);
  20                 if (attrs != INVALID_FILE_ATTRIBUTES && (attrs & FILE_ATTRIBUTE_DIRECTORY))
  21                         errno = EISDIR;
  22         }
  23         return fd;
  24 }
  25
  26 unsigned int sleep (unsigned int seconds)
  27 {
  28         Sleep(seconds*1000);
  29         return 0;
  30 }
  31
  32 int mkstemp(char *template)
  33 {
  34         char *filename = mktemp(template);
  35         if (filename == NULL)
  36                 return -1;
  37         return open(filename, O_RDWR | O_CREAT, 0600);
  38 }
  39
  40 int gettimeofday(struct timeval *tv, void *tz)
  41 {
  42         SYSTEMTIME st;
  43         struct tm tm;
  44         GetSystemTime(&st);
  45         tm.tm_year = st.wYear-1900;
  46         tm.tm_mon = st.wMonth-1;
  47         tm.tm_mday = st.wDay;
  48         tm.tm_hour = st.wHour;
  49         tm.tm_min = st.wMinute;
  50         tm.tm_sec = st.wSecond;
  51         tv->tv_sec = tm_to_time_t(&tm);
  52         if (tv->tv_sec < 0)
  53                 return -1;
  54         tv->tv_usec = st.wMilliseconds*1000;
  55         return 0;
  56 }
  57
  58 int pipe(int filedes[2])
  59 {
  60         int fd;
  61         HANDLE h[2], parent;
  62
  63         if (_pipe(filedes, 8192, 0) < 0)
  64                 return -1;
  65
  66         parent = GetCurrentProcess();
  67
  68         if (!DuplicateHandle (parent, (HANDLE)_get_osfhandle(filedes[0]),
  69                         parent, &h[0], 0, FALSE, DUPLICATE_SAME_ACCESS)) {
  70                 close(filedes[0]);
  71                 close(filedes[1]);
  72                 return -1;
  73         }
  74         if (!DuplicateHandle (parent, (HANDLE)_get_osfhandle(filedes[1]),
  75                         parent, &h[1], 0, FALSE, DUPLICATE_SAME_ACCESS)) {
  76                 close(filedes[0]);
  77                 close(filedes[1]);
  78                 CloseHandle(h[0]);
  79                 return -1;
  80         }
  81         fd = _open_osfhandle((int)h[0], O_NOINHERIT);
  82         if (fd < 0) {
  83                 close(filedes[0]);
  84                 close(filedes[1]);
  85                 CloseHandle(h[0]);
  86                 CloseHandle(h[1]);
  87                 return -1;
  88         }
  89         close(filedes[0]);
  90         filedes[0] = fd;
  91         fd = _open_osfhandle((int)h[1], O_NOINHERIT);
  92         if (fd < 0) {
  93                 close(filedes[0]);
  94                 close(filedes[1]);
  95                 CloseHandle(h[1]);
  96                 return -1;
  97         }
  98         close(filedes[1]);
  99         filedes[1] = fd;
 100         return 0;
 101 }
 102
 103 int poll(struct pollfd *ufds, unsigned int nfds, int timeout)
 104 {
 105         int i, pending;
 106
 107         if (timeout != -1)
 108                 return errno = EINVAL, error("poll timeout not supported");
 109
 110         /* When there is only one fd to wait for, then we pretend that
 111          * input is available and let the actual wait happen when the
 112          * caller invokes read().
 113          */
 114         if (nfds == 1) {
 115                 if (!(ufds[0].events & POLLIN))
 116                         return errno = EINVAL, error("POLLIN not set");
 117                 ufds[0].revents = POLLIN;
 118                 return 0;
 119         }
 120
 121 repeat:
 122         pending = 0;
 123         for (i = 0; i < nfds; i++) {
 124                 DWORD avail = 0;
 125                 HANDLE h = (HANDLE) _get_osfhandle(ufds[i].fd);
 126                 if (h == INVALID_HANDLE_VALUE)
 127                         return -1;      /* errno was set */
 128
 129                 if (!(ufds[i].events & POLLIN))
 130                         return errno = EINVAL, error("POLLIN not set");
 131
 132                 /* this emulation works only for pipes */
 133                 if (!PeekNamedPipe(h, NULL, 0, NULL, &avail, NULL)) {
 134                         int err = GetLastError();
 135                         if (err == ERROR_BROKEN_PIPE) {
 136                                 ufds[i].revents = POLLHUP;
 137                                 pending++;
 138                         } else {
 139                                 errno = EINVAL;
 140                                 return error("PeekNamedPipe failed,"
 141                                         " GetLastError: %u", err);
 142                         }
 143                 } else if (avail) {
 144                         ufds[i].revents = POLLIN;
 145                         pending++;
 146                 } else
 147                         ufds[i].revents = 0;
 148         }
 149         if (!pending) {
 150                 /* The only times that we spin here is when the process
 151                  * that is connected through the pipes is waiting for
 152                  * its own input data to become available. But since
 153                  * the process (pack-objects) is itself CPU intensive,
 154                  * it will happily pick up the time slice that we are
 155                  * relinguishing here.
 156                  */
 157                 Sleep(0);
 158                 goto repeat;
 159         }
 160         return 0;
 161 }
 162
 163 struct tm *gmtime_r(const time_t *timep, struct tm *result)
 164 {
 165         /* gmtime() in MSVCRT.DLL is thread-safe, but not reentrant */
 166         memcpy(result, gmtime(timep), sizeof(struct tm));
 167         return result;
 168 }
 169
 170 struct tm *localtime_r(const time_t *timep, struct tm *result)
 171 {
 172         /* localtime() in MSVCRT.DLL is thread-safe, but not reentrant */
 173         memcpy(result, localtime(timep), sizeof(struct tm));
 174         return result;
 175 }
 176
 177 #undef getcwd
 178 char *mingw_getcwd(char *pointer, int len)
 179 {
 180         int i;
 181         char *ret = getcwd(pointer, len);
 182         if (!ret)
 183                 return ret;
 184         for (i = 0; pointer[i]; i++)
 185                 if (pointer[i] == '\\')
 186                         pointer[i] = '/';
 187         return ret;
 188 }
 189
 190 /*
 191  * See http://msdn2.microsoft.com/en-us/library/17w5ykft(vs.71).aspx
 192  * (Parsing C++ Command-Line Arguments)
 193  */
 194 static const char *quote_arg(const char *arg)
 195 {
 196         /* count chars to quote */
 197         int len = 0, n = 0;
 198         int force_quotes = 0;
 199         char *q, *d;
 200         const char *p = arg;
 201         if (!*p) force_quotes = 1;
 202         while (*p) {
 203                 if (isspace(*p) || *p == '*' || *p == '?' || *p == '{')
 204                         force_quotes = 1;
 205                 else if (*p == '"')
 206                         n++;
 207                 else if (*p == '\\') {
 208                         int count = 0;
 209                         while (*p == '\\') {
 210                                 count++;
 211                                 p++;
 212                                 len++;
 213                         }
 214                         if (*p == '"')
 215                                 n += count*2 + 1;
 216                         continue;
 217                 }
 218                 len++;
 219                 p++;
 220         }
 221         if (!force_quotes && n == 0)
 222                 return arg;
 223
 224         /* insert \ where necessary */
 225         d = q = xmalloc(len+n+3);
 226         *d++ = '"';
 227         while (*arg) {
 228                 if (*arg == '"')
 229                         *d++ = '\\';
 230                 else if (*arg == '\\') {
 231                         int count = 0;
 232                         while (*arg == '\\') {
 233                                 count++;
 234                                 *d++ = *arg++;
 235                         }
 236                         if (*arg == '"') {
 237                                 while (count-- > 0)
 238                                         *d++ = '\\';
 239                                 *d++ = '\\';
 240                         }
 241                 }
 242                 *d++ = *arg++;
 243         }
 244         *d++ = '"';
 245         *d++ = 0;
 246         return q;
 247 }
 248
 249 static const char *parse_interpreter(const char *cmd)
 250 {
 251         static char buf[100];
 252         char *p, *opt;
 253         int n, fd;
 254
 255         /* don't even try a .exe */
 256         n = strlen(cmd);
 257         if (n >= 4 && !strcasecmp(cmd+n-4, ".exe"))
 258                 return NULL;
 259
 260         fd = open(cmd, O_RDONLY);
 261         if (fd < 0)
 262                 return NULL;
 263         n = read(fd, buf, sizeof(buf)-1);
 264         close(fd);
 265         if (n < 4)      /* at least '#!/x' and not error */
 266                 return NULL;
 267
 268         if (buf[0] != '#' || buf[1] != '!')
 269                 return NULL;
 270         buf[n] = '\0';
 271         p = strchr(buf, '\n');
 272         if (!p)
 273                 return NULL;
 274
 275         *p = '\0';
 276         if (!(p = strrchr(buf+2, '/')) && !(p = strrchr(buf+2, '\\')))
 277                 return NULL;
 278         /* strip options */
 279         if ((opt = strchr(p+1, ' ')))
 280                 *opt = '\0';
 281         return p+1;
 282 }
 283
 284 /*
 285  * Splits the PATH into parts.
 286  */
 287 static char **get_path_split(void)
 288 {
 289         char *p, **path, *envpath = getenv("PATH");
 290         int i, n = 0;
 291
 292         if (!envpath || !*envpath)
 293                 return NULL;
 294
 295         envpath = xstrdup(envpath);
 296         p = envpath;
 297         while (p) {
 298                 char *dir = p;
 299                 p = strchr(p, ';');
 300                 if (p) *p++ = '\0';
 301                 if (*dir) {     /* not earlier, catches series of ; */
 302                         ++n;
 303                 }
 304         }
 305         if (!n)
 306                 return NULL;
 307
 308         path = xmalloc((n+1)*sizeof(char*));
 309         p = envpath;
 310         i = 0;
 311         do {
 312                 if (*p)
 313                         path[i++] = xstrdup(p);
 314                 p = p+strlen(p)+1;
 315         } while (i < n);
 316         path[i] = NULL;
 317
 318         free(envpath);
 319
 320         return path;
 321 }
 322
 323 static void free_path_split(char **path)
 324 {
 325         if (!path)
 326                 return;
 327
 328         char **p = path;
 329         while (*p)
 330                 free(*p++);
 331         free(path);
 332 }
 333
 334 /*
 335  * exe_only means that we only want to detect .exe files, but not scripts
 336  * (which do not have an extension)
 337  */
 338 static char *lookup_prog(const char *dir, const char *cmd, int isexe, int exe_only)
 339 {
 340         char path[MAX_PATH];
 341         snprintf(path, sizeof(path), "%s/%s.exe", dir, cmd);
 342
 343         if (!isexe && access(path, F_OK) == 0)
 344                 return xstrdup(path);
 345         path[strlen(path)-4] = '\0';
 346         if ((!exe_only || isexe) && access(path, F_OK) == 0)
 347                 return xstrdup(path);
 348         return NULL;
 349 }
 350
 351 /*
 352  * Determines the absolute path of cmd using the the split path in path.
 353  * If cmd contains a slash or backslash, no lookup is performed.
 354  */
 355 static char *path_lookup(const char *cmd, char **path, int exe_only)
 356 {
 357         char *prog = NULL;
 358         int len = strlen(cmd);
 359         int isexe = len >= 4 && !strcasecmp(cmd+len-4, ".exe");
 360
 361         if (strchr(cmd, '/') || strchr(cmd, '\\'))
 362                 prog = xstrdup(cmd);
 363
 364         while (!prog && *path)
 365                 prog = lookup_prog(*path++, cmd, isexe, exe_only);
 366
 367         return prog;
 368 }
 369
 370 static int env_compare(const void *a, const void *b)
 371 {
 372         char *const *ea = a;
 373         char *const *eb = b;
 374         return strcasecmp(*ea, *eb);
 375 }
 376
 377 static pid_t mingw_spawnve(const char *cmd, const char **argv, char **env,
 378                            int prepend_cmd)
 379 {
 380         STARTUPINFO si;
 381         PROCESS_INFORMATION pi;
 382         struct strbuf envblk, args;
 383         unsigned flags;
 384         BOOL ret;
 385
 386         /* Determine whether or not we are associated to a console */
 387         HANDLE cons = CreateFile("CONOUT$", GENERIC_WRITE,
 388                         FILE_SHARE_WRITE, NULL, OPEN_EXISTING,
 389                         FILE_ATTRIBUTE_NORMAL, NULL);
 390         if (cons == INVALID_HANDLE_VALUE) {
 391                 /* There is no console associated with this process.
 392                  * Since the child is a console process, Windows
 393                  * would normally create a console window. But
 394                  * since we'll be redirecting std streams, we do
 395                  * not need the console.
 396                  */
 397                 flags = CREATE_NO_WINDOW;
 398         } else {
 399                 /* There is already a console. If we specified
 400                  * CREATE_NO_WINDOW here, too, Windows would
 401                  * disassociate the child from the console.
 402                  * Go figure!
 403                  */
 404                 flags = 0;
 405                 CloseHandle(cons);
 406         }
 407         memset(&si, 0, sizeof(si));
 408         si.cb = sizeof(si);
 409         si.dwFlags = STARTF_USESTDHANDLES;
 410         si.hStdInput = (HANDLE) _get_osfhandle(0);
 411         si.hStdOutput = (HANDLE) _get_osfhandle(1);
 412         si.hStdError = (HANDLE) _get_osfhandle(2);
 413
 414         /* concatenate argv, quoting args as we go */
 415         strbuf_init(&args, 0);
 416         if (prepend_cmd) {
 417                 char *quoted = (char *)quote_arg(cmd);
 418                 strbuf_addstr(&args, quoted);
 419                 if (quoted != cmd)
 420                         free(quoted);
 421         }
 422         for (; *argv; argv++) {
 423                 char *quoted = (char *)quote_arg(*argv);
 424                 if (*args.buf)
 425                         strbuf_addch(&args, ' ');
 426                 strbuf_addstr(&args, quoted);
 427                 if (quoted != *argv)
 428                         free(quoted);
 429         }
 430
 431         if (env) {
 432                 int count = 0;
 433                 char **e, **sorted_env;
 434
 435                 for (e = env; *e; e++)
 436                         count++;
 437
 438                 /* environment must be sorted */
 439                 sorted_env = xmalloc(sizeof(*sorted_env) * (count + 1));
 440                 memcpy(sorted_env, env, sizeof(*sorted_env) * (count + 1));
 441                 qsort(sorted_env, count, sizeof(*sorted_env), env_compare);
 442
 443                 strbuf_init(&envblk, 0);
 444                 for (e = sorted_env; *e; e++) {
 445                         strbuf_addstr(&envblk, *e);
 446                         strbuf_addch(&envblk, '\0');
 447                 }
 448                 free(sorted_env);
 449         }
 450
 451         memset(&pi, 0, sizeof(pi));
 452         ret = CreateProcess(cmd, args.buf, NULL, NULL, TRUE, flags,
 453                 env ? envblk.buf : NULL, NULL, &si, &pi);
 454
 455         if (env)
 456                 strbuf_release(&envblk);
 457         strbuf_release(&args);
 458
 459         if (!ret) {
 460                 errno = ENOENT;
 461                 return -1;
 462         }
 463         CloseHandle(pi.hThread);
 464         return (pid_t)pi.hProcess;
 465 }
 466
 467 pid_t mingw_spawnvpe(const char *cmd, const char **argv, char **env)
 468 {
 469         pid_t pid;
 470         char **path = get_path_split();
 471         char *prog = path_lookup(cmd, path, 0);
 472
 473         if (!prog) {
 474                 errno = ENOENT;
 475                 pid = -1;
 476         }
 477         else {
 478                 const char *interpr = parse_interpreter(prog);
 479
 480                 if (interpr) {
 481                         const char *argv0 = argv[0];
 482                         char *iprog = path_lookup(interpr, path, 1);
 483                         argv[0] = prog;
 484                         if (!iprog) {
 485                                 errno = ENOENT;
 486                                 pid = -1;
 487                         }
 488                         else {
 489                                 pid = mingw_spawnve(iprog, argv, env, 1);
 490                                 free(iprog);
 491                         }
 492                         argv[0] = argv0;
 493                 }
 494                 else
 495                         pid = mingw_spawnve(prog, argv, env, 0);
 496                 free(prog);
 497         }
 498         free_path_split(path);
 499         return pid;
 500 }
 501
 502 static int try_shell_exec(const char *cmd, char *const *argv, char **env)
 503 {
 504         const char *interpr = parse_interpreter(cmd);
 505         char **path;
 506         char *prog;
 507         int pid = 0;
 508
 509         if (!interpr)
 510                 return 0;
 511         path = get_path_split();
 512         prog = path_lookup(interpr, path, 1);
 513         if (prog) {
 514                 int argc = 0;
 515                 const char **argv2;
 516                 while (argv[argc]) argc++;
 517                 argv2 = xmalloc(sizeof(*argv) * (argc+1));
 518                 argv2[0] = (char *)cmd; /* full path to the script file */
 519                 memcpy(&argv2[1], &argv[1], sizeof(*argv) * argc);
 520                 pid = mingw_spawnve(prog, argv2, env, 1);
 521                 if (pid >= 0) {
 522                         int status;
 523                         if (waitpid(pid, &status, 0) < 0)
 524                                 status = 255;
 525                         exit(status);
 526                 }
 527                 pid = 1;        /* indicate that we tried but failed */
 528                 free(prog);
 529                 free(argv2);
 530         }
 531         free_path_split(path);
 532         return pid;
 533 }
 534
 535 static void mingw_execve(const char *cmd, char *const *argv, char *const *env)
 536 {
 537         /* check if git_command is a shell script */
 538         if (!try_shell_exec(cmd, argv, (char **)env)) {
 539                 int pid, status;
 540
 541                 pid = mingw_spawnve(cmd, (const char **)argv, (char **)env, 0);
 542                 if (pid < 0)
 543                         return;
 544                 if (waitpid(pid, &status, 0) < 0)
 545                         status = 255;
 546                 exit(status);
 547         }
 548 }
 549
 550 void mingw_execvp(const char *cmd, char *const *argv)
 551 {
 552         char **path = get_path_split();
 553         char *prog = path_lookup(cmd, path, 0);
 554
 555         if (prog) {
 556                 mingw_execve(prog, argv, environ);
 557                 free(prog);
 558         } else
 559                 errno = ENOENT;
 560
 561         free_path_split(path);
 562 }
 563
 564 char **copy_environ()
 565 {
 566         char **env;
 567         int i = 0;
 568         while (environ[i])
 569                 i++;
 570         env = xmalloc((i+1)*sizeof(*env));
 571         for (i = 0; environ[i]; i++)
 572                 env[i] = xstrdup(environ[i]);
 573         env[i] = NULL;
 574         return env;
 575 }
 576
 577 void free_environ(char **env)
 578 {
 579         int i;
 580         for (i = 0; env[i]; i++)
 581                 free(env[i]);
 582         free(env);
 583 }
 584
 585 static int lookup_env(char **env, const char *name, size_t nmln)
 586 {
 587         int i;
 588
 589         for (i = 0; env[i]; i++) {
 590                 if (0 == strncmp(env[i], name, nmln)
 591                     && '=' == env[i][nmln])
 592                         /* matches */
 593                         return i;
 594         }
 595         return -1;
 596 }
 597
 598 /*
 599  * If name contains '=', then sets the variable, otherwise it unsets it
 600  */
 601 char **env_setenv(char **env, const char *name)
 602 {
 603         char *eq = strchrnul(name, '=');
 604         int i = lookup_env(env, name, eq-name);
 605
 606         if (i < 0) {
 607                 if (*eq) {
 608                         for (i = 0; env[i]; i++)
 609                                 ;
 610                         env = xrealloc(env, (i+2)*sizeof(*env));
 611                         env[i] = xstrdup(name);
 612                         env[i+1] = NULL;
 613                 }
 614         }
 615         else {
 616                 free(env[i]);
 617                 if (*eq)
 618                         env[i] = xstrdup(name);
 619                 else
 620                         for (; env[i]; i++)
 621                                 env[i] = env[i+1];
 622         }
 623         return env;
 624 }
 625
 626 /* this is the first function to call into WS_32; initialize it */
 627 #undef gethostbyname
 628 struct hostent *mingw_gethostbyname(const char *host)
 629 {
 630         WSADATA wsa;
 631
 632         if (WSAStartup(MAKEWORD(2,2), &wsa))
 633                 die("unable to initialize winsock subsystem, error %d",
 634                         WSAGetLastError());
 635         atexit((void(*)(void)) WSACleanup);
 636         return gethostbyname(host);
 637 }
 638
 639 int mingw_socket(int domain, int type, int protocol)
 640 {
 641         int sockfd;
 642         SOCKET s = WSASocket(domain, type, protocol, NULL, 0, 0);
 643         if (s == INVALID_SOCKET) {
 644                 /*
 645                  * WSAGetLastError() values are regular BSD error codes
 646                  * biased by WSABASEERR.
 647                  * However, strerror() does not know about networking
 648                  * specific errors, which are values beginning at 38 or so.
 649                  * Therefore, we choose to leave the biased error code
 650                  * in errno so that _if_ someone looks up the code somewhere,
 651                  * then it is at least the number that are usually listed.
 652                  */
 653                 errno = WSAGetLastError();
 654                 return -1;
 655         }
 656         /* convert into a file descriptor */
 657         if ((sockfd = _open_osfhandle(s, O_RDWR|O_BINARY)) < 0) {
 658                 closesocket(s);
 659                 return error("unable to make a socket file descriptor: %s",
 660                         strerror(errno));
 661         }
 662         return sockfd;
 663 }
 664
 665 #undef connect
 666 int mingw_connect(int sockfd, struct sockaddr *sa, size_t sz)
 667 {
 668         SOCKET s = (SOCKET)_get_osfhandle(sockfd);
 669         return connect(s, sa, sz);
 670 }
 671
 672 #undef rename
 673 int mingw_rename(const char *pold, const char *pnew)
 674 {
 675         /*
 676          * Try native rename() first to get errno right.
 677          * It is based on MoveFile(), which cannot overwrite existing files.
 678          */
 679         if (!rename(pold, pnew))
 680                 return 0;
 681         if (errno != EEXIST)
 682                 return -1;
 683         if (MoveFileEx(pold, pnew, MOVEFILE_REPLACE_EXISTING))
 684                 return 0;
 685         /* TODO: translate more errors */
 686         if (GetLastError() == ERROR_ACCESS_DENIED) {
 687                 DWORD attrs = GetFileAttributes(pnew);
 688                 if (attrs != INVALID_FILE_ATTRIBUTES && (attrs & FILE_ATTRIBUTE_DIRECTORY)) {
 689                         errno = EISDIR;
 690                         return -1;
 691                 }
 692         }
 693         errno = EACCES;
 694         return -1;
 695 }
 696
 697 struct passwd *getpwuid(int uid)
 698 {
 699         static char user_name[100];
 700         static struct passwd p;
 701
 702         DWORD len = sizeof(user_name);
 703         if (!GetUserName(user_name, &len))
 704                 return NULL;
 705         p.pw_name = user_name;
 706         p.pw_gecos = "unknown";
 707         p.pw_dir = NULL;
 708         return &p;
 709 }
 710
 711 static HANDLE timer_event;
 712 static HANDLE timer_thread;
 713 static int timer_interval;
 714 static int one_shot;
 715 static sig_handler_t timer_fn = SIG_DFL;
 716
 717 /* The timer works like this:
 718  * The thread, ticktack(), is a trivial routine that most of the time
 719  * only waits to receive the signal to terminate. The main thread tells
 720  * the thread to terminate by setting the timer_event to the signalled
 721  * state.
 722  * But ticktack() interrupts the wait state after the timer's interval
 723  * length to call the signal handler.
 724  */
 725
 726 static __stdcall unsigned ticktack(void *dummy)
 727 {
 728         while (WaitForSingleObject(timer_event, timer_interval) == WAIT_TIMEOUT) {
 729                 if (timer_fn == SIG_DFL)
 730                         die("Alarm");
 731                 if (timer_fn != SIG_IGN)
 732                         timer_fn(SIGALRM);
 733                 if (one_shot)
 734                         break;
 735         }
 736         return 0;
 737 }
 738
 739 static int start_timer_thread(void)
 740 {
 741         timer_event = CreateEvent(NULL, FALSE, FALSE, NULL);
 742         if (timer_event) {
 743                 timer_thread = (HANDLE) _beginthreadex(NULL, 0, ticktack, NULL, 0, NULL);
 744                 if (!timer_thread )
 745                         return errno = ENOMEM,
 746                                 error("cannot start timer thread");
 747         } else
 748                 return errno = ENOMEM,
 749                         error("cannot allocate resources for timer");
 750         return 0;
 751 }
 752
 753 static void stop_timer_thread(void)
 754 {
 755         if (timer_event)
 756                 SetEvent(timer_event);  /* tell thread to terminate */
 757         if (timer_thread) {
 758                 int rc = WaitForSingleObject(timer_thread, 1000);
 759                 if (rc == WAIT_TIMEOUT)
 760                         error("timer thread did not terminate timely");
 761                 else if (rc != WAIT_OBJECT_0)
 762                         error("waiting for timer thread failed: %lu",
 763                               GetLastError());
 764                 CloseHandle(timer_thread);
 765         }
 766         if (timer_event)
 767                 CloseHandle(timer_event);
 768         timer_event = NULL;
 769         timer_thread = NULL;
 770 }
 771
 772 static inline int is_timeval_eq(const struct timeval *i1, const struct timeval *i2)
 773 {
 774         return i1->tv_sec == i2->tv_sec && i1->tv_usec == i2->tv_usec;
 775 }
 776
 777 int setitimer(int type, struct itimerval *in, struct itimerval *out)
 778 {
 779         static const struct timeval zero;
 780         static int atexit_done;
 781
 782         if (out != NULL)
 783                 return errno = EINVAL,
 784                         error("setitimer param 3 != NULL not implemented");
 785         if (!is_timeval_eq(&in->it_interval, &zero) &&
 786             !is_timeval_eq(&in->it_interval, &in->it_value))
 787                 return errno = EINVAL,
 788                         error("setitimer: it_interval must be zero or eq it_value");
 789
 790         if (timer_thread)
 791                 stop_timer_thread();
 792
 793         if (is_timeval_eq(&in->it_value, &zero) &&
 794             is_timeval_eq(&in->it_interval, &zero))
 795                 return 0;
 796
 797         timer_interval = in->it_value.tv_sec * 1000 + in->it_value.tv_usec / 1000;
 798         one_shot = is_timeval_eq(&in->it_interval, &zero);
 799         if (!atexit_done) {
 800                 atexit(stop_timer_thread);
 801                 atexit_done = 1;
 802         }
 803         return start_timer_thread();
 804 }
 805
 806 int sigaction(int sig, struct sigaction *in, struct sigaction *out)
 807 {
 808         if (sig != SIGALRM)
 809                 return errno = EINVAL,
 810                         error("sigaction only implemented for SIGALRM");
 811         if (out != NULL)
 812                 return errno = EINVAL,
 813                         error("sigaction: param 3 != NULL not implemented");
 814
 815         timer_fn = in->sa_handler;
 816         return 0;
 817 }
 818
 819 #undef signal
 820 sig_handler_t mingw_signal(int sig, sig_handler_t handler)
 821 {
 822         if (sig != SIGALRM)
 823                 return signal(sig, handler);
 824         sig_handler_t old = timer_fn;
 825         timer_fn = handler;
 826         return old;
 827 }