src/runtime/wrap.c

   1 /*
   2  * wrappers around low-level operations to provide a simpler interface
   3  * to the operations that Lisp (and some contributed modules) needs.
   4  *
   5  * The functions in this file are typically called directly from Lisp.
   6  * Thus, when their signature changes, they don't need updates in a .h
   7  * file somewhere, but they do need updates in the Lisp code. FIXME:
   8  * It would be nice to enforce this at compile time. It mighn't even
   9  * be all that hard: make the cross-compiler versions of DEFINE-ALIEN-FOO
  10  * macros accumulate strings in a list which then gets written out at
  11  * the end of sbcl2.h at the end of cross-compilation, then rerun
  12  * 'make' in src/runtime/ using the new sbcl2.h as sbcl.h (and make
  13  * sure that all the files in src/runtime/ include sbcl.h). */
  14
  15 /*
  16  * This software is part of the SBCL system. See the README file for
  17  * more information.
  18  *
  19  * This software is derived from the CMU CL system, which was
  20  * written at Carnegie Mellon University and released into the
  21  * public domain. The software is in the public domain and is
  22  * provided with absolutely no warranty. See the COPYING and CREDITS
  23  * files for more information.
  24  */
  25
  26 #include "sbcl.h"
  27
  28 #include <sys/types.h>
  29 #include <dirent.h>
  30 #include <sys/stat.h>
  31 #include <stdlib.h>
  32 #include <string.h>
  33 #include <ctype.h>
  34 #include <unistd.h>
  35 #include <errno.h>
  36 #include <limits.h>
  37 #ifndef LISP_FEATURE_WIN32
  38 #include <pwd.h>
  39 #include <sys/wait.h>
  40 #include <netdb.h>
  41 #endif
  42 #include <stdio.h>
  43
  44 #if defined(LISP_FEATURE_WIN32)
  45 #define WIN32_LEAN_AND_MEAN
  46 #include <fcntl.h>
  47 #include <errno.h>
  48 #endif
  49
  50 #include "runtime.h"
  51 #include "util.h"
  52 #include "wrap.h"
  53
  54 /* Although it might seem as though this should be in some standard
  55    Unix header, according to Perry E. Metzger, in a message on
  56    sbcl-devel dated 2004-03-29, this is the POSIXly-correct way of
  57    using environ: by an explicit declaration.  -- CSR, 2004-03-30 */
  58 extern char **environ;
  59 \f
  60 /*
  61  * stuff needed by CL:DIRECTORY and other Lisp directory operations
  62  */
  63
  64 /* Unix directory operations think of "." and ".." as filenames, but
  65  * Lisp directory operations do not. */
  66 int
  67 is_lispy_filename(const char *filename)
  68 {
  69     return strcmp(filename, ".") && strcmp(filename, "..");
  70 }
  71
  72 /* Return a zero-terminated array of strings holding the Lispy filenames
  73  * (i.e. excluding the Unix magic "." and "..") in the named directory. */
  74 char**
  75 alloc_directory_lispy_filenames(const char *directory_name)
  76 {
  77     DIR *dir_ptr = opendir(directory_name);
  78     char **result = 0;
  79
  80     if (dir_ptr) { /* if opendir success */
  81
  82         struct voidacc va;
  83
  84         if (0 == voidacc_ctor(&va)) { /* if voidacc_ctor success */
  85             struct dirent *dirent_ptr;
  86
  87             while ( (dirent_ptr = readdir(dir_ptr)) ) { /* until end of data */
  88                 char* original_name = dirent_ptr->d_name;
  89                 if (is_lispy_filename(original_name)) {
  90                     /* strdup(3) is in Linux and *BSD. If you port
  91                      * somewhere else that doesn't have it, it's easy
  92                      * to reimplement. */
  93                     char* dup_name = strdup(original_name);
  94                     if (!dup_name) { /* if strdup failure */
  95                         goto dtors;
  96                     }
  97                     if (voidacc_acc(&va, dup_name)) { /* if acc failure */
  98                         goto dtors;
  99                     }
 100                 }
 101             }
 102             result = (char**)voidacc_give_away_result(&va);
 103         }
 104
 105     dtors:
 106         voidacc_dtor(&va);
 107         /* ignoring closedir(3) return code, since what could we do?
 108          *
 109          * "Never ask questions you don't want to know the answer to."
 110          * -- William Irving Zumwalt (Rich Cook, _The Wizardry Quested_) */
 111         closedir(dir_ptr);
 112     }
 113
 114     return result;
 115 }
 116
 117 /* Free a result returned by alloc_directory_lispy_filenames(). */
 118 void
 119 free_directory_lispy_filenames(char** directory_lispy_filenames)
 120 {
 121     char** p;
 122
 123     /* Free the strings. */
 124     for (p = directory_lispy_filenames; *p; ++p) {
 125         free(*p);
 126     }
 127
 128     /* Free the table of strings. */
 129     free(directory_lispy_filenames);
 130 }
 131 \f
 132 /*
 133  * readlink(2) stuff
 134  */
 135
 136 #ifndef LISP_FEATURE_WIN32
 137 /* a wrapped version of readlink(2):
 138  *   -- If path isn't a symlink, or is a broken symlink, return 0.
 139  *   -- If path is a symlink, return a newly allocated string holding
 140  *      the thing it's linked to. */
 141 char *
 142 wrapped_readlink(char *path)
 143 {
 144     int bufsiz = strlen(path) + 16;
 145     while (1) {
 146         char *result = malloc(bufsiz);
 147         int n_read = readlink(path, result, bufsiz);
 148         if (n_read < 0) {
 149             free(result);
 150             return 0;
 151         } else if (n_read < bufsiz) {
 152             result[n_read] = 0;
 153             return result;
 154         } else {
 155             free(result);
 156             bufsiz *= 2;
 157         }
 158     }
 159 }
 160 #endif
 161 \f
 162 /*
 163  * realpath(3), including a wrapper for Windows.
 164  */
 165 char * sb_realpath (char *path)
 166 {
 167 #ifndef LISP_FEATURE_WIN32
 168     char *ret;
 169     int errnum;
 170
 171     if ((ret = calloc(PATH_MAX, sizeof(char))) == NULL)
 172         return NULL;
 173     if (realpath(path, ret) == NULL) {
 174         errnum = errno;
 175         free(ret);
 176         errno = errnum;
 177         return NULL;
 178     }
 179     return(ret);
 180 #else
 181     char *ret;
 182     char *cp;
 183     int errnum;
 184
 185     if ((ret = calloc(MAX_PATH, sizeof(char))) == NULL)
 186         return NULL;
 187     if (GetFullPathName(path, MAX_PATH, ret, cp) == 0) {
 188         errnum = errno;
 189         free(ret);
 190         errno = errnum;
 191         return NULL;
 192     }
 193     return(ret);
 194 #endif
 195 }
 196 \f
 197 /*
 198  * stat(2) stuff
 199  */
 200
 201 static void
 202 copy_to_stat_wrapper(struct stat_wrapper *to, struct stat *from)
 203 {
 204 #define FROB(stem) to->wrapped_st_##stem = from->st_##stem
 205 #ifndef LISP_FEATURE_WIN32
 206 #define FROB2(stem) to->wrapped_st_##stem = from->st_##stem
 207 #else
 208 #define FROB2(stem) to->wrapped_st_##stem = 0;
 209 #endif
 210     FROB(dev);
 211     FROB2(ino);
 212     FROB(mode);
 213     FROB(nlink);
 214     FROB2(uid);
 215     FROB2(gid);
 216     FROB(rdev);
 217     FROB(size);
 218     FROB2(blksize);
 219     FROB2(blocks);
 220     FROB(atime);
 221     FROB(mtime);
 222     FROB(ctime);
 223 #undef FROB
 224 }
 225
 226 int
 227 stat_wrapper(const char *file_name, struct stat_wrapper *buf)
 228 {
 229     struct stat real_buf;
 230     int ret;
 231
 232 #ifdef LISP_FEATURE_WIN32
 233     /*
 234      * Windows won't match the last component of a pathname if there
 235      * is a trailing #\/ or #\\, except if it's <drive>:\ or <drive>:/
 236      * in which case it behaves the other way around. So we remove the
 237      * trailing directory separator unless we are being passed just a
 238      * drive name (e.g. "c:\\").  Some, but not all, of this
 239      * strangeness is documented at Microsoft's support site (as of
 240      * 2006-01-08, at
 241      * <http://support.microsoft.com/default.aspx?scid=kb;en-us;168439>)
 242      */
 243     char file_buf[MAX_PATH];
 244     strcpy(file_buf, file_name);
 245     int len = strlen(file_name);
 246     if (len != 0 && (file_name[len-1] == '/' || file_name[len-1] == '\\') &&
 247         !(len == 3 && file_name[1] == ':' && isalpha(file_name[0])))
 248         file_buf[len-1] = '\0';
 249     file_name = file_buf;
 250 #endif
 251
 252     if ((ret = stat(file_name,&real_buf)) >= 0)
 253         copy_to_stat_wrapper(buf, &real_buf);
 254     return ret;
 255 }
 256
 257 #ifndef LISP_FEATURE_WIN32
 258 int
 259 lstat_wrapper(const char *file_name, struct stat_wrapper *buf)
 260 {
 261     struct stat real_buf;
 262     int ret;
 263     if ((ret = lstat(file_name,&real_buf)) >= 0)
 264         copy_to_stat_wrapper(buf, &real_buf);
 265     return ret;
 266 }
 267 #else
 268 /* cleaner to do it here than in Lisp */
 269 int lstat_wrapper(const char *file_name, struct stat_wrapper *buf)
 270 {
 271     return stat_wrapper(file_name, buf);
 272 }
 273 #endif
 274
 275 int
 276 fstat_wrapper(int filedes, struct stat_wrapper *buf)
 277 {
 278     struct stat real_buf;
 279     int ret;
 280     if ((ret = fstat(filedes,&real_buf)) >= 0)
 281         copy_to_stat_wrapper(buf, &real_buf);
 282     return ret;
 283 }
 284 \f
 285 /* A wrapper for mkstemp(3), which seems not to exist on Windows. */
 286 int sb_mkstemp (char *template) {
 287 #ifdef LISP_FEATURE_WIN32
 288   int fd;
 289   char buf[MAX_PATH];
 290
 291   while (1) {
 292     strcpy((char*)&buf, template);
 293     if (_mktemp((char*)&buf)) {
 294       if ((fd=open((char*)&buf, O_CREAT|O_EXCL|O_RDWR, S_IRUSR|S_IWUSR))!=-1) {
 295         strcpy(template, (char*)&buf);
 296         return (fd);
 297       } else
 298         if (errno != EEXIST)
 299           return (-1);
 300     } else
 301       return (-1);
 302   }
 303 #else
 304   return(mkstemp(template));
 305 #endif
 306 }
 307
 308 \f
 309 /*
 310  * getpwuid() stuff
 311  */
 312
 313 #ifndef LISP_FEATURE_WIN32
 314 /* Return a newly-allocated string holding the username for "uid", or
 315  * NULL if there's no such user.
 316  *
 317  * KLUDGE: We also return NULL if malloc() runs out of memory
 318  * (returning strdup() result) since it's not clear how to handle that
 319  * error better. -- WHN 2001-12-28 */
 320 char *
 321 uid_username(int uid)
 322 {
 323     struct passwd *p = getpwuid(uid);
 324     if (p) {
 325         /* The object *p is a static struct which'll be overwritten by
 326          * the next call to getpwuid(), so it'd be unsafe to return
 327          * p->pw_name without copying. */
 328         return strdup(p->pw_name);
 329     } else {
 330         return 0;
 331     }
 332 }
 333
 334 char *
 335 uid_homedir(uid_t uid)
 336 {
 337     struct passwd *p = getpwuid(uid);
 338     if(p) {
 339         /* Let's be careful about this, shall we? */
 340         size_t len = strlen(p->pw_dir);
 341         if (p->pw_dir[len-1] == '/') {
 342             return strdup(p->pw_dir);
 343         } else {
 344             char *result = malloc(len + 2);
 345             if (result) {
 346                 int nchars = sprintf(result,"%s/",p->pw_dir);
 347                 if (nchars == len + 1) {
 348                     return result;
 349                 } else {
 350                     return 0;
 351                 }
 352             } else {
 353                 return 0;
 354             }
 355         }
 356     } else {
 357         return 0;
 358     }
 359 }
 360 #endif /* !LISP_FEATURE_WIN32 */
 361 \f
 362 /*
 363  * functions to get miscellaneous C-level variables
 364  *
 365  * (Doing this by calling functions lets us borrow the smarts of the C
 366  * linker, so that things don't blow up when libc versions and thus
 367  * variable locations change between compile time and run time.)
 368  */
 369
 370 char **
 371 wrapped_environ()
 372 {
 373     return environ;
 374 }
 375
 376 #ifdef LISP_FEATURE_WIN32
 377 #include <windows.h>
 378 #include <time.h>
 379 /*
 380  * faked-up implementation of select(). Right now just enough to get through
 381  * second genesis.
 382  */
 383 int select(int top_fd, DWORD *read_set, DWORD *write_set, DWORD *except_set, time_t *timeout)
 384 {
 385     /*
 386      * FIXME: Going forward, we may want to use MsgWaitForMultipleObjects
 387      * in order to support a windows message loop inside serve-event.
 388      */
 389     HANDLE handles[MAXIMUM_WAIT_OBJECTS];
 390     int fds[MAXIMUM_WAIT_OBJECTS];
 391     int num_handles;
 392     int i;
 393     DWORD retval;
 394     int polling_write;
 395     DWORD win_timeout;
 396
 397     num_handles = 0;
 398     polling_write = 0;
 399     for (i = 0; i < top_fd; i++) {
 400         if (except_set) except_set[i >> 5] = 0;
 401         if (write_set && (write_set[i >> 5] & (1 << (i & 31)))) polling_write = 1;
 402         if (read_set[i >> 5] & (1 << (i & 31))) {
 403             read_set[i >> 5] &= ~(1 << (i & 31));
 404             fds[num_handles] = i;
 405             handles[num_handles++] = (HANDLE) _get_osfhandle(i);
 406         }
 407     }
 408
 409     win_timeout = INFINITE;
 410     if (timeout) win_timeout = (timeout[0] * 1000) + timeout[1];
 411
 412     /* Last parameter here is timeout in milliseconds. */
 413     /* retval = WaitForMultipleObjects(num_handles, handles, 0, INFINITE); */
 414     retval = WaitForMultipleObjects(num_handles, handles, 0, win_timeout);
 415
 416     if (retval < WAIT_ABANDONED) {
 417         /* retval, at this point, is the index of the single live HANDLE/fd. */
 418         read_set[fds[retval] >> 5] |= (1 << (fds[retval] & 31));
 419         return 1;
 420     }
 421     return polling_write;
 422 }
 423
 424 /*
 425  * Windows doesn't have gettimeofday(), and we need it for the compiler,
 426  * for serve-event, and for a couple other things. We don't need a timezone
 427  * yet, however, and the closest we can easily get to a timeval is the
 428  * seconds part. So that's what we do.
 429  */
 430 int gettimeofday(long *timeval, long *timezone)
 431 {
 432     timeval[0] = time(NULL);
 433     timeval[1] = 0;
 434
 435     return 0;
 436 }
 437 #endif
 438
 439
 440 /* We will need to define these things or their equivalents for Win32
 441    eventually, but for now let's get it working for everyone else. */
 442 #ifndef LISP_FEATURE_WIN32
 443 /* From SB-BSD-SOCKETS, to get h_errno */
 444 int get_h_errno()
 445 {
 446     return h_errno;
 447 }
 448
 449 /* From SB-POSIX, wait-macros */
 450 int wifexited(int status) {
 451     return WIFEXITED(status);
 452 }
 453 int wexitstatus(int status) {
 454     return WEXITSTATUS(status);
 455 }
 456 int wifsignaled(int status) {
 457     return WIFSIGNALED(status);
 458 }
 459 int wtermsig(int status) {
 460     return WTERMSIG(status);
 461 }
 462 int wifstopped(int status) {
 463     return WIFSTOPPED(status);
 464 }
 465 int wstopsig(int status) {
 466     return WSTOPSIG(status);
 467 }
 468 /* FIXME: POSIX also defines WIFCONTINUED, but that appears not to
 469    exist on at least Linux... */
 470 #endif  /* !LISP_FEATURE_WIN32 */
 471
 472 /* From SB-POSIX, stat-macros */
 473 int s_isreg(mode_t mode)
 474 {
 475     return S_ISREG(mode);
 476 }
 477 int s_isdir(mode_t mode)
 478 {
 479     return S_ISDIR(mode);
 480 }
 481 int s_ischr(mode_t mode)
 482 {
 483     return S_ISCHR(mode);
 484 }
 485 int s_isblk(mode_t mode)
 486 {
 487     return S_ISBLK(mode);
 488 }
 489 int s_isfifo(mode_t mode)
 490 {
 491     return S_ISFIFO(mode);
 492 }
 493 #ifndef LISP_FEATURE_WIN32
 494 int s_islnk(mode_t mode)
 495 {
 496 #ifdef S_ISLNK
 497     return S_ISLNK(mode);
 498 #else
 499     return ((mode & S_IFMT) == S_IFLNK);
 500 #endif
 501 }
 502 int s_issock(mode_t mode)
 503 {
 504 #ifdef S_ISSOCK
 505     return S_ISSOCK(mode);
 506 #else
 507     return ((mode & S_IFMT) == S_IFSOCK);
 508 #endif
 509 }
 510 #endif /* !LISP_FEATURE_WIN32 */