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 static inline time_t filetime_to_time_t(const FILETIME *ft)
  27 {
  28         long long winTime = ((long long)ft->dwHighDateTime << 32) + ft->dwLowDateTime;
  29         winTime -= 116444736000000000LL; /* Windows to Unix Epoch conversion */
  30         winTime /= 10000000;             /* Nano to seconds resolution */
  31         return (time_t)winTime;
  32 }
  33
  34 extern int _getdrive( void );
  35 /* We keep the do_lstat code in a separate function to avoid recursion.
  36  * When a path ends with a slash, the stat will fail with ENOENT. In
  37  * this case, we strip the trailing slashes and stat again.
  38  */
  39 static int do_lstat(const char *file_name, struct stat *buf)
  40 {
  41         WIN32_FILE_ATTRIBUTE_DATA fdata;
  42
  43         if (GetFileAttributesExA(file_name, GetFileExInfoStandard, &fdata)) {
  44                 int fMode = S_IREAD;
  45                 if (fdata.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY)
  46                         fMode |= S_IFDIR;
  47                 else
  48                         fMode |= S_IFREG;
  49                 if (!(fdata.dwFileAttributes & FILE_ATTRIBUTE_READONLY))
  50                         fMode |= S_IWRITE;
  51
  52                 buf->st_ino = 0;
  53                 buf->st_gid = 0;
  54                 buf->st_uid = 0;
  55                 buf->st_nlink = 1;
  56                 buf->st_mode = fMode;
  57                 buf->st_size = fdata.nFileSizeLow; /* Can't use nFileSizeHigh, since it's not a stat64 */
  58                 buf->st_dev = buf->st_rdev = (_getdrive() - 1);
  59                 buf->st_atime = filetime_to_time_t(&(fdata.ftLastAccessTime));
  60                 buf->st_mtime = filetime_to_time_t(&(fdata.ftLastWriteTime));
  61                 buf->st_ctime = filetime_to_time_t(&(fdata.ftCreationTime));
  62                 errno = 0;
  63                 return 0;
  64         }
  65
  66         switch (GetLastError()) {
  67         case ERROR_ACCESS_DENIED:
  68         case ERROR_SHARING_VIOLATION:
  69         case ERROR_LOCK_VIOLATION:
  70         case ERROR_SHARING_BUFFER_EXCEEDED:
  71                 errno = EACCES;
  72                 break;
  73         case ERROR_BUFFER_OVERFLOW:
  74                 errno = ENAMETOOLONG;
  75                 break;
  76         case ERROR_NOT_ENOUGH_MEMORY:
  77                 errno = ENOMEM;
  78                 break;
  79         default:
  80                 errno = ENOENT;
  81                 break;
  82         }
  83         return -1;
  84 }
  85
  86 /* We provide our own lstat/fstat functions, since the provided
  87  * lstat/fstat functions are so slow. These stat functions are
  88  * tailored for Git's usage (read: fast), and are not meant to be
  89  * complete. Note that Git stat()s are redirected to mingw_lstat()
  90  * too, since Windows doesn't really handle symlinks that well.
  91  */
  92 int mingw_lstat(const char *file_name, struct stat *buf)
  93 {
  94         int namelen;
  95         static char alt_name[PATH_MAX];
  96
  97         if (!do_lstat(file_name, buf))
  98                 return 0;
  99
 100         /* if file_name ended in a '/', Windows returned ENOENT;
 101          * try again without trailing slashes
 102          */
 103         if (errno != ENOENT)
 104                 return -1;
 105
 106         namelen = strlen(file_name);
 107         if (namelen && file_name[namelen-1] != '/')
 108                 return -1;
 109         while (namelen && file_name[namelen-1] == '/')
 110                 --namelen;
 111         if (!namelen || namelen >= PATH_MAX)
 112                 return -1;
 113
 114         memcpy(alt_name, file_name, namelen);
 115         alt_name[namelen] = 0;
 116         return do_lstat(alt_name, buf);
 117 }
 118
 119 #undef fstat
 120 int mingw_fstat(int fd, struct stat *buf)
 121 {
 122         HANDLE fh = (HANDLE)_get_osfhandle(fd);
 123         BY_HANDLE_FILE_INFORMATION fdata;
 124
 125         if (fh == INVALID_HANDLE_VALUE) {
 126                 errno = EBADF;
 127                 return -1;
 128         }
 129         /* direct non-file handles to MS's fstat() */
 130         if (GetFileType(fh) != FILE_TYPE_DISK)
 131                 return fstat(fd, buf);
 132
 133         if (GetFileInformationByHandle(fh, &fdata)) {
 134                 int fMode = S_IREAD;
 135                 if (fdata.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY)
 136                         fMode |= S_IFDIR;
 137                 else
 138                         fMode |= S_IFREG;
 139                 if (!(fdata.dwFileAttributes & FILE_ATTRIBUTE_READONLY))
 140                         fMode |= S_IWRITE;
 141
 142                 buf->st_ino = 0;
 143                 buf->st_gid = 0;
 144                 buf->st_uid = 0;
 145                 buf->st_nlink = 1;
 146                 buf->st_mode = fMode;
 147                 buf->st_size = fdata.nFileSizeLow; /* Can't use nFileSizeHigh, since it's not a stat64 */
 148                 buf->st_dev = buf->st_rdev = (_getdrive() - 1);
 149                 buf->st_atime = filetime_to_time_t(&(fdata.ftLastAccessTime));
 150                 buf->st_mtime = filetime_to_time_t(&(fdata.ftLastWriteTime));
 151                 buf->st_ctime = filetime_to_time_t(&(fdata.ftCreationTime));
 152                 return 0;
 153         }
 154         errno = EBADF;
 155         return -1;
 156 }
 157
 158 unsigned int sleep (unsigned int seconds)
 159 {
 160         Sleep(seconds*1000);
 161         return 0;
 162 }
 163
 164 int mkstemp(char *template)
 165 {
 166         char *filename = mktemp(template);
 167         if (filename == NULL)
 168                 return -1;
 169         return open(filename, O_RDWR | O_CREAT, 0600);
 170 }
 171
 172 int gettimeofday(struct timeval *tv, void *tz)
 173 {
 174         SYSTEMTIME st;
 175         struct tm tm;
 176         GetSystemTime(&st);
 177         tm.tm_year = st.wYear-1900;
 178         tm.tm_mon = st.wMonth-1;
 179         tm.tm_mday = st.wDay;
 180         tm.tm_hour = st.wHour;
 181         tm.tm_min = st.wMinute;
 182         tm.tm_sec = st.wSecond;
 183         tv->tv_sec = tm_to_time_t(&tm);
 184         if (tv->tv_sec < 0)
 185                 return -1;
 186         tv->tv_usec = st.wMilliseconds*1000;
 187         return 0;
 188 }
 189
 190 int pipe(int filedes[2])
 191 {
 192         int fd;
 193         HANDLE h[2], parent;
 194
 195         if (_pipe(filedes, 8192, 0) < 0)
 196                 return -1;
 197
 198         parent = GetCurrentProcess();
 199
 200         if (!DuplicateHandle (parent, (HANDLE)_get_osfhandle(filedes[0]),
 201                         parent, &h[0], 0, FALSE, DUPLICATE_SAME_ACCESS)) {
 202                 close(filedes[0]);
 203                 close(filedes[1]);
 204                 return -1;
 205         }
 206         if (!DuplicateHandle (parent, (HANDLE)_get_osfhandle(filedes[1]),
 207                         parent, &h[1], 0, FALSE, DUPLICATE_SAME_ACCESS)) {
 208                 close(filedes[0]);
 209                 close(filedes[1]);
 210                 CloseHandle(h[0]);
 211                 return -1;
 212         }
 213         fd = _open_osfhandle((int)h[0], O_NOINHERIT);
 214         if (fd < 0) {
 215                 close(filedes[0]);
 216                 close(filedes[1]);
 217                 CloseHandle(h[0]);
 218                 CloseHandle(h[1]);
 219                 return -1;
 220         }
 221         close(filedes[0]);
 222         filedes[0] = fd;
 223         fd = _open_osfhandle((int)h[1], O_NOINHERIT);
 224         if (fd < 0) {
 225                 close(filedes[0]);
 226                 close(filedes[1]);
 227                 CloseHandle(h[1]);
 228                 return -1;
 229         }
 230         close(filedes[1]);
 231         filedes[1] = fd;
 232         return 0;
 233 }
 234
 235 int poll(struct pollfd *ufds, unsigned int nfds, int timeout)
 236 {
 237         int i, pending;
 238
 239         if (timeout != -1)
 240                 return errno = EINVAL, error("poll timeout not supported");
 241
 242         /* When there is only one fd to wait for, then we pretend that
 243          * input is available and let the actual wait happen when the
 244          * caller invokes read().
 245          */
 246         if (nfds == 1) {
 247                 if (!(ufds[0].events & POLLIN))
 248                         return errno = EINVAL, error("POLLIN not set");
 249                 ufds[0].revents = POLLIN;
 250                 return 0;
 251         }
 252
 253 repeat:
 254         pending = 0;
 255         for (i = 0; i < nfds; i++) {
 256                 DWORD avail = 0;
 257                 HANDLE h = (HANDLE) _get_osfhandle(ufds[i].fd);
 258                 if (h == INVALID_HANDLE_VALUE)
 259                         return -1;      /* errno was set */
 260
 261                 if (!(ufds[i].events & POLLIN))
 262                         return errno = EINVAL, error("POLLIN not set");
 263
 264                 /* this emulation works only for pipes */
 265                 if (!PeekNamedPipe(h, NULL, 0, NULL, &avail, NULL)) {
 266                         int err = GetLastError();
 267                         if (err == ERROR_BROKEN_PIPE) {
 268                                 ufds[i].revents = POLLHUP;
 269                                 pending++;
 270                         } else {
 271                                 errno = EINVAL;
 272                                 return error("PeekNamedPipe failed,"
 273                                         " GetLastError: %u", err);
 274                         }
 275                 } else if (avail) {
 276                         ufds[i].revents = POLLIN;
 277                         pending++;
 278                 } else
 279                         ufds[i].revents = 0;
 280         }
 281         if (!pending) {
 282                 /* The only times that we spin here is when the process
 283                  * that is connected through the pipes is waiting for
 284                  * its own input data to become available. But since
 285                  * the process (pack-objects) is itself CPU intensive,
 286                  * it will happily pick up the time slice that we are
 287                  * relinguishing here.
 288                  */
 289                 Sleep(0);
 290                 goto repeat;
 291         }
 292         return 0;
 293 }
 294
 295 struct tm *gmtime_r(const time_t *timep, struct tm *result)
 296 {
 297         /* gmtime() in MSVCRT.DLL is thread-safe, but not reentrant */
 298         memcpy(result, gmtime(timep), sizeof(struct tm));
 299         return result;
 300 }
 301
 302 struct tm *localtime_r(const time_t *timep, struct tm *result)
 303 {
 304         /* localtime() in MSVCRT.DLL is thread-safe, but not reentrant */
 305         memcpy(result, localtime(timep), sizeof(struct tm));
 306         return result;
 307 }
 308
 309 #undef getcwd
 310 char *mingw_getcwd(char *pointer, int len)
 311 {
 312         int i;
 313         char *ret = getcwd(pointer, len);
 314         if (!ret)
 315                 return ret;
 316         for (i = 0; pointer[i]; i++)
 317                 if (pointer[i] == '\\')
 318                         pointer[i] = '/';
 319         return ret;
 320 }
 321
 322 /*
 323  * See http://msdn2.microsoft.com/en-us/library/17w5ykft(vs.71).aspx
 324  * (Parsing C++ Command-Line Arguments)
 325  */
 326 static const char *quote_arg(const char *arg)
 327 {
 328         /* count chars to quote */
 329         int len = 0, n = 0;
 330         int force_quotes = 0;
 331         char *q, *d;
 332         const char *p = arg;
 333         if (!*p) force_quotes = 1;
 334         while (*p) {
 335                 if (isspace(*p) || *p == '*' || *p == '?' || *p == '{')
 336                         force_quotes = 1;
 337                 else if (*p == '"')
 338                         n++;
 339                 else if (*p == '\\') {
 340                         int count = 0;
 341                         while (*p == '\\') {
 342                                 count++;
 343                                 p++;
 344                                 len++;
 345                         }
 346                         if (*p == '"')
 347                                 n += count*2 + 1;
 348                         continue;
 349                 }
 350                 len++;
 351                 p++;
 352         }
 353         if (!force_quotes && n == 0)
 354                 return arg;
 355
 356         /* insert \ where necessary */
 357         d = q = xmalloc(len+n+3);
 358         *d++ = '"';
 359         while (*arg) {
 360                 if (*arg == '"')
 361                         *d++ = '\\';
 362                 else if (*arg == '\\') {
 363                         int count = 0;
 364                         while (*arg == '\\') {
 365                                 count++;
 366                                 *d++ = *arg++;
 367                         }
 368                         if (*arg == '"') {
 369                                 while (count-- > 0)
 370                                         *d++ = '\\';
 371                                 *d++ = '\\';
 372                         }
 373                 }
 374                 *d++ = *arg++;
 375         }
 376         *d++ = '"';
 377         *d++ = 0;
 378         return q;
 379 }
 380
 381 static const char *parse_interpreter(const char *cmd)
 382 {
 383         static char buf[100];
 384         char *p, *opt;
 385         int n, fd;
 386
 387         /* don't even try a .exe */
 388         n = strlen(cmd);
 389         if (n >= 4 && !strcasecmp(cmd+n-4, ".exe"))
 390                 return NULL;
 391
 392         fd = open(cmd, O_RDONLY);
 393         if (fd < 0)
 394                 return NULL;
 395         n = read(fd, buf, sizeof(buf)-1);
 396         close(fd);
 397         if (n < 4)      /* at least '#!/x' and not error */
 398                 return NULL;
 399
 400         if (buf[0] != '#' || buf[1] != '!')
 401                 return NULL;
 402         buf[n] = '\0';
 403         p = strchr(buf, '\n');
 404         if (!p)
 405                 return NULL;
 406
 407         *p = '\0';
 408         if (!(p = strrchr(buf+2, '/')) && !(p = strrchr(buf+2, '\\')))
 409                 return NULL;
 410         /* strip options */
 411         if ((opt = strchr(p+1, ' ')))
 412                 *opt = '\0';
 413         return p+1;
 414 }
 415
 416 /*
 417  * Splits the PATH into parts.
 418  */
 419 static char **get_path_split(void)
 420 {
 421         char *p, **path, *envpath = getenv("PATH");
 422         int i, n = 0;
 423
 424         if (!envpath || !*envpath)
 425                 return NULL;
 426
 427         envpath = xstrdup(envpath);
 428         p = envpath;
 429         while (p) {
 430                 char *dir = p;
 431                 p = strchr(p, ';');
 432                 if (p) *p++ = '\0';
 433                 if (*dir) {     /* not earlier, catches series of ; */
 434                         ++n;
 435                 }
 436         }
 437         if (!n)
 438                 return NULL;
 439
 440         path = xmalloc((n+1)*sizeof(char*));
 441         p = envpath;
 442         i = 0;
 443         do {
 444                 if (*p)
 445                         path[i++] = xstrdup(p);
 446                 p = p+strlen(p)+1;
 447         } while (i < n);
 448         path[i] = NULL;
 449
 450         free(envpath);
 451
 452         return path;
 453 }
 454
 455 static void free_path_split(char **path)
 456 {
 457         if (!path)
 458                 return;
 459
 460         char **p = path;
 461         while (*p)
 462                 free(*p++);
 463         free(path);
 464 }
 465
 466 /*
 467  * exe_only means that we only want to detect .exe files, but not scripts
 468  * (which do not have an extension)
 469  */
 470 static char *lookup_prog(const char *dir, const char *cmd, int isexe, int exe_only)
 471 {
 472         char path[MAX_PATH];
 473         snprintf(path, sizeof(path), "%s/%s.exe", dir, cmd);
 474
 475         if (!isexe && access(path, F_OK) == 0)
 476                 return xstrdup(path);
 477         path[strlen(path)-4] = '\0';
 478         if ((!exe_only || isexe) && access(path, F_OK) == 0)
 479                 return xstrdup(path);
 480         return NULL;
 481 }
 482
 483 /*
 484  * Determines the absolute path of cmd using the the split path in path.
 485  * If cmd contains a slash or backslash, no lookup is performed.
 486  */
 487 static char *path_lookup(const char *cmd, char **path, int exe_only)
 488 {
 489         char *prog = NULL;
 490         int len = strlen(cmd);
 491         int isexe = len >= 4 && !strcasecmp(cmd+len-4, ".exe");
 492
 493         if (strchr(cmd, '/') || strchr(cmd, '\\'))
 494                 prog = xstrdup(cmd);
 495
 496         while (!prog && *path)
 497                 prog = lookup_prog(*path++, cmd, isexe, exe_only);
 498
 499         return prog;
 500 }
 501
 502 static int env_compare(const void *a, const void *b)
 503 {
 504         char *const *ea = a;
 505         char *const *eb = b;
 506         return strcasecmp(*ea, *eb);
 507 }
 508
 509 static pid_t mingw_spawnve(const char *cmd, const char **argv, char **env,
 510                            int prepend_cmd)
 511 {
 512         STARTUPINFO si;
 513         PROCESS_INFORMATION pi;
 514         struct strbuf envblk, args;
 515         unsigned flags;
 516         BOOL ret;
 517
 518         /* Determine whether or not we are associated to a console */
 519         HANDLE cons = CreateFile("CONOUT$", GENERIC_WRITE,
 520                         FILE_SHARE_WRITE, NULL, OPEN_EXISTING,
 521                         FILE_ATTRIBUTE_NORMAL, NULL);
 522         if (cons == INVALID_HANDLE_VALUE) {
 523                 /* There is no console associated with this process.
 524                  * Since the child is a console process, Windows
 525                  * would normally create a console window. But
 526                  * since we'll be redirecting std streams, we do
 527                  * not need the console.
 528                  */
 529                 flags = CREATE_NO_WINDOW;
 530         } else {
 531                 /* There is already a console. If we specified
 532                  * CREATE_NO_WINDOW here, too, Windows would
 533                  * disassociate the child from the console.
 534                  * Go figure!
 535                  */
 536                 flags = 0;
 537                 CloseHandle(cons);
 538         }
 539         memset(&si, 0, sizeof(si));
 540         si.cb = sizeof(si);
 541         si.dwFlags = STARTF_USESTDHANDLES;
 542         si.hStdInput = (HANDLE) _get_osfhandle(0);
 543         si.hStdOutput = (HANDLE) _get_osfhandle(1);
 544         si.hStdError = (HANDLE) _get_osfhandle(2);
 545
 546         /* concatenate argv, quoting args as we go */
 547         strbuf_init(&args, 0);
 548         if (prepend_cmd) {
 549                 char *quoted = (char *)quote_arg(cmd);
 550                 strbuf_addstr(&args, quoted);
 551                 if (quoted != cmd)
 552                         free(quoted);
 553         }
 554         for (; *argv; argv++) {
 555                 char *quoted = (char *)quote_arg(*argv);
 556                 if (*args.buf)
 557                         strbuf_addch(&args, ' ');
 558                 strbuf_addstr(&args, quoted);
 559                 if (quoted != *argv)
 560                         free(quoted);
 561         }
 562
 563         if (env) {
 564                 int count = 0;
 565                 char **e, **sorted_env;
 566
 567                 for (e = env; *e; e++)
 568                         count++;
 569
 570                 /* environment must be sorted */
 571                 sorted_env = xmalloc(sizeof(*sorted_env) * (count + 1));
 572                 memcpy(sorted_env, env, sizeof(*sorted_env) * (count + 1));
 573                 qsort(sorted_env, count, sizeof(*sorted_env), env_compare);
 574
 575                 strbuf_init(&envblk, 0);
 576                 for (e = sorted_env; *e; e++) {
 577                         strbuf_addstr(&envblk, *e);
 578                         strbuf_addch(&envblk, '\0');
 579                 }
 580                 free(sorted_env);
 581         }
 582
 583         memset(&pi, 0, sizeof(pi));
 584         ret = CreateProcess(cmd, args.buf, NULL, NULL, TRUE, flags,
 585                 env ? envblk.buf : NULL, NULL, &si, &pi);
 586
 587         if (env)
 588                 strbuf_release(&envblk);
 589         strbuf_release(&args);
 590
 591         if (!ret) {
 592                 errno = ENOENT;
 593                 return -1;
 594         }
 595         CloseHandle(pi.hThread);
 596         return (pid_t)pi.hProcess;
 597 }
 598
 599 pid_t mingw_spawnvpe(const char *cmd, const char **argv, char **env)
 600 {
 601         pid_t pid;
 602         char **path = get_path_split();
 603         char *prog = path_lookup(cmd, path, 0);
 604
 605         if (!prog) {
 606                 errno = ENOENT;
 607                 pid = -1;
 608         }
 609         else {
 610                 const char *interpr = parse_interpreter(prog);
 611
 612                 if (interpr) {
 613                         const char *argv0 = argv[0];
 614                         char *iprog = path_lookup(interpr, path, 1);
 615                         argv[0] = prog;
 616                         if (!iprog) {
 617                                 errno = ENOENT;
 618                                 pid = -1;
 619                         }
 620                         else {
 621                                 pid = mingw_spawnve(iprog, argv, env, 1);
 622                                 free(iprog);
 623                         }
 624                         argv[0] = argv0;
 625                 }
 626                 else
 627                         pid = mingw_spawnve(prog, argv, env, 0);
 628                 free(prog);
 629         }
 630         free_path_split(path);
 631         return pid;
 632 }
 633
 634 static int try_shell_exec(const char *cmd, char *const *argv, char **env)
 635 {
 636         const char *interpr = parse_interpreter(cmd);
 637         char **path;
 638         char *prog;
 639         int pid = 0;
 640
 641         if (!interpr)
 642                 return 0;
 643         path = get_path_split();
 644         prog = path_lookup(interpr, path, 1);
 645         if (prog) {
 646                 int argc = 0;
 647                 const char **argv2;
 648                 while (argv[argc]) argc++;
 649                 argv2 = xmalloc(sizeof(*argv) * (argc+1));
 650                 argv2[0] = (char *)cmd; /* full path to the script file */
 651                 memcpy(&argv2[1], &argv[1], sizeof(*argv) * argc);
 652                 pid = mingw_spawnve(prog, argv2, env, 1);
 653                 if (pid >= 0) {
 654                         int status;
 655                         if (waitpid(pid, &status, 0) < 0)
 656                                 status = 255;
 657                         exit(status);
 658                 }
 659                 pid = 1;        /* indicate that we tried but failed */
 660                 free(prog);
 661                 free(argv2);
 662         }
 663         free_path_split(path);
 664         return pid;
 665 }
 666
 667 static void mingw_execve(const char *cmd, char *const *argv, char *const *env)
 668 {
 669         /* check if git_command is a shell script */
 670         if (!try_shell_exec(cmd, argv, (char **)env)) {
 671                 int pid, status;
 672
 673                 pid = mingw_spawnve(cmd, (const char **)argv, (char **)env, 0);
 674                 if (pid < 0)
 675                         return;
 676                 if (waitpid(pid, &status, 0) < 0)
 677                         status = 255;
 678                 exit(status);
 679         }
 680 }
 681
 682 void mingw_execvp(const char *cmd, char *const *argv)
 683 {
 684         char **path = get_path_split();
 685         char *prog = path_lookup(cmd, path, 0);
 686
 687         if (prog) {
 688                 mingw_execve(prog, argv, environ);
 689                 free(prog);
 690         } else
 691                 errno = ENOENT;
 692
 693         free_path_split(path);
 694 }
 695
 696 char **copy_environ()
 697 {
 698         char **env;
 699         int i = 0;
 700         while (environ[i])
 701                 i++;
 702         env = xmalloc((i+1)*sizeof(*env));
 703         for (i = 0; environ[i]; i++)
 704                 env[i] = xstrdup(environ[i]);
 705         env[i] = NULL;
 706         return env;
 707 }
 708
 709 void free_environ(char **env)
 710 {
 711         int i;
 712         for (i = 0; env[i]; i++)
 713                 free(env[i]);
 714         free(env);
 715 }
 716
 717 static int lookup_env(char **env, const char *name, size_t nmln)
 718 {
 719         int i;
 720
 721         for (i = 0; env[i]; i++) {
 722                 if (0 == strncmp(env[i], name, nmln)
 723                     && '=' == env[i][nmln])
 724                         /* matches */
 725                         return i;
 726         }
 727         return -1;
 728 }
 729
 730 /*
 731  * If name contains '=', then sets the variable, otherwise it unsets it
 732  */
 733 char **env_setenv(char **env, const char *name)
 734 {
 735         char *eq = strchrnul(name, '=');
 736         int i = lookup_env(env, name, eq-name);
 737
 738         if (i < 0) {
 739                 if (*eq) {
 740                         for (i = 0; env[i]; i++)
 741                                 ;
 742                         env = xrealloc(env, (i+2)*sizeof(*env));
 743                         env[i] = xstrdup(name);
 744                         env[i+1] = NULL;
 745                 }
 746         }
 747         else {
 748                 free(env[i]);
 749                 if (*eq)
 750                         env[i] = xstrdup(name);
 751                 else
 752                         for (; env[i]; i++)
 753                                 env[i] = env[i+1];
 754         }
 755         return env;
 756 }
 757
 758 /* this is the first function to call into WS_32; initialize it */
 759 #undef gethostbyname
 760 struct hostent *mingw_gethostbyname(const char *host)
 761 {
 762         WSADATA wsa;
 763
 764         if (WSAStartup(MAKEWORD(2,2), &wsa))
 765                 die("unable to initialize winsock subsystem, error %d",
 766                         WSAGetLastError());
 767         atexit((void(*)(void)) WSACleanup);
 768         return gethostbyname(host);
 769 }
 770
 771 int mingw_socket(int domain, int type, int protocol)
 772 {
 773         int sockfd;
 774         SOCKET s = WSASocket(domain, type, protocol, NULL, 0, 0);
 775         if (s == INVALID_SOCKET) {
 776                 /*
 777                  * WSAGetLastError() values are regular BSD error codes
 778                  * biased by WSABASEERR.
 779                  * However, strerror() does not know about networking
 780                  * specific errors, which are values beginning at 38 or so.
 781                  * Therefore, we choose to leave the biased error code
 782                  * in errno so that _if_ someone looks up the code somewhere,
 783                  * then it is at least the number that are usually listed.
 784                  */
 785                 errno = WSAGetLastError();
 786                 return -1;
 787         }
 788         /* convert into a file descriptor */
 789         if ((sockfd = _open_osfhandle(s, O_RDWR|O_BINARY)) < 0) {
 790                 closesocket(s);
 791                 return error("unable to make a socket file descriptor: %s",
 792                         strerror(errno));
 793         }
 794         return sockfd;
 795 }
 796
 797 #undef connect
 798 int mingw_connect(int sockfd, struct sockaddr *sa, size_t sz)
 799 {
 800         SOCKET s = (SOCKET)_get_osfhandle(sockfd);
 801         return connect(s, sa, sz);
 802 }
 803
 804 #undef rename
 805 int mingw_rename(const char *pold, const char *pnew)
 806 {
 807         /*
 808          * Try native rename() first to get errno right.
 809          * It is based on MoveFile(), which cannot overwrite existing files.
 810          */
 811         if (!rename(pold, pnew))
 812                 return 0;
 813         if (errno != EEXIST)
 814                 return -1;
 815         if (MoveFileEx(pold, pnew, MOVEFILE_REPLACE_EXISTING))
 816                 return 0;
 817         /* TODO: translate more errors */
 818         if (GetLastError() == ERROR_ACCESS_DENIED) {
 819                 DWORD attrs = GetFileAttributes(pnew);
 820                 if (attrs != INVALID_FILE_ATTRIBUTES && (attrs & FILE_ATTRIBUTE_DIRECTORY)) {
 821                         errno = EISDIR;
 822                         return -1;
 823                 }
 824         }
 825         errno = EACCES;
 826         return -1;
 827 }
 828
 829 struct passwd *getpwuid(int uid)
 830 {
 831         static char user_name[100];
 832         static struct passwd p;
 833
 834         DWORD len = sizeof(user_name);
 835         if (!GetUserName(user_name, &len))
 836                 return NULL;
 837         p.pw_name = user_name;
 838         p.pw_gecos = "unknown";
 839         p.pw_dir = NULL;
 840         return &p;
 841 }
 842
 843 static HANDLE timer_event;
 844 static HANDLE timer_thread;
 845 static int timer_interval;
 846 static int one_shot;
 847 static sig_handler_t timer_fn = SIG_DFL;
 848
 849 /* The timer works like this:
 850  * The thread, ticktack(), is a trivial routine that most of the time
 851  * only waits to receive the signal to terminate. The main thread tells
 852  * the thread to terminate by setting the timer_event to the signalled
 853  * state.
 854  * But ticktack() interrupts the wait state after the timer's interval
 855  * length to call the signal handler.
 856  */
 857
 858 static __stdcall unsigned ticktack(void *dummy)
 859 {
 860         while (WaitForSingleObject(timer_event, timer_interval) == WAIT_TIMEOUT) {
 861                 if (timer_fn == SIG_DFL)
 862                         die("Alarm");
 863                 if (timer_fn != SIG_IGN)
 864                         timer_fn(SIGALRM);
 865                 if (one_shot)
 866                         break;
 867         }
 868         return 0;
 869 }
 870
 871 static int start_timer_thread(void)
 872 {
 873         timer_event = CreateEvent(NULL, FALSE, FALSE, NULL);
 874         if (timer_event) {
 875                 timer_thread = (HANDLE) _beginthreadex(NULL, 0, ticktack, NULL, 0, NULL);
 876                 if (!timer_thread )
 877                         return errno = ENOMEM,
 878                                 error("cannot start timer thread");
 879         } else
 880                 return errno = ENOMEM,
 881                         error("cannot allocate resources for timer");
 882         return 0;
 883 }
 884
 885 static void stop_timer_thread(void)
 886 {
 887         if (timer_event)
 888                 SetEvent(timer_event);  /* tell thread to terminate */
 889         if (timer_thread) {
 890                 int rc = WaitForSingleObject(timer_thread, 1000);
 891                 if (rc == WAIT_TIMEOUT)
 892                         error("timer thread did not terminate timely");
 893                 else if (rc != WAIT_OBJECT_0)
 894                         error("waiting for timer thread failed: %lu",
 895                               GetLastError());
 896                 CloseHandle(timer_thread);
 897         }
 898         if (timer_event)
 899                 CloseHandle(timer_event);
 900         timer_event = NULL;
 901         timer_thread = NULL;
 902 }
 903
 904 static inline int is_timeval_eq(const struct timeval *i1, const struct timeval *i2)
 905 {
 906         return i1->tv_sec == i2->tv_sec && i1->tv_usec == i2->tv_usec;
 907 }
 908
 909 int setitimer(int type, struct itimerval *in, struct itimerval *out)
 910 {
 911         static const struct timeval zero;
 912         static int atexit_done;
 913
 914         if (out != NULL)
 915                 return errno = EINVAL,
 916                         error("setitimer param 3 != NULL not implemented");
 917         if (!is_timeval_eq(&in->it_interval, &zero) &&
 918             !is_timeval_eq(&in->it_interval, &in->it_value))
 919                 return errno = EINVAL,
 920                         error("setitimer: it_interval must be zero or eq it_value");
 921
 922         if (timer_thread)
 923                 stop_timer_thread();
 924
 925         if (is_timeval_eq(&in->it_value, &zero) &&
 926             is_timeval_eq(&in->it_interval, &zero))
 927                 return 0;
 928
 929         timer_interval = in->it_value.tv_sec * 1000 + in->it_value.tv_usec / 1000;
 930         one_shot = is_timeval_eq(&in->it_interval, &zero);
 931         if (!atexit_done) {
 932                 atexit(stop_timer_thread);
 933                 atexit_done = 1;
 934         }
 935         return start_timer_thread();
 936 }
 937
 938 int sigaction(int sig, struct sigaction *in, struct sigaction *out)
 939 {
 940         if (sig != SIGALRM)
 941                 return errno = EINVAL,
 942                         error("sigaction only implemented for SIGALRM");
 943         if (out != NULL)
 944                 return errno = EINVAL,
 945                         error("sigaction: param 3 != NULL not implemented");
 946
 947         timer_fn = in->sa_handler;
 948         return 0;
 949 }
 950
 951 #undef signal
 952 sig_handler_t mingw_signal(int sig, sig_handler_t handler)
 953 {
 954         if (sig != SIGALRM)
 955                 return signal(sig, handler);
 956         sig_handler_t old = timer_fn;
 957         timer_fn = handler;
 958         return old;
 959 }