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 #include <fcntl.h>
  38
  39 #ifndef LISP_FEATURE_WIN32
  40 #include <pwd.h>
  41 #include <sys/wait.h>
  42 #include <netdb.h>
  43 #endif
  44 #include <stdio.h>
  45
  46 #if defined(LISP_FEATURE_WIN32)
  47 #define WIN32_LEAN_AND_MEAN
  48 #include <errno.h>
  49 #endif
  50
  51 #include "runtime.h"
  52 #include "util.h"
  53 #include "wrap.h"
  54
  55 /* Although it might seem as though this should be in some standard
  56    Unix header, according to Perry E. Metzger, in a message on
  57    sbcl-devel dated 2004-03-29, this is the POSIXly-correct way of
  58    using environ: by an explicit declaration.  -- CSR, 2004-03-30 */
  59 extern char **environ;
  60 \f
  61 /*
  62  * stuff needed by CL:DIRECTORY and other Lisp directory operations
  63  */
  64
  65 /* Unix directory operations think of "." and ".." as filenames, but
  66  * Lisp directory operations do not. */
  67 int
  68 is_lispy_filename(const char *filename)
  69 {
  70     return strcmp(filename, ".") && strcmp(filename, "..");
  71 }
  72
  73 /* Return a zero-terminated array of strings holding the Lispy filenames
  74  * (i.e. excluding the Unix magic "." and "..") in the named directory. */
  75 char**
  76 alloc_directory_lispy_filenames(const char *directory_name)
  77 {
  78     DIR *dir_ptr = opendir(directory_name);
  79     char **result = 0;
  80
  81     if (dir_ptr) { /* if opendir success */
  82
  83         struct voidacc va;
  84
  85         if (0 == voidacc_ctor(&va)) { /* if voidacc_ctor success */
  86             struct dirent *dirent_ptr;
  87
  88             while ( (dirent_ptr = readdir(dir_ptr)) ) { /* until end of data */
  89                 char* original_name = dirent_ptr->d_name;
  90                 if (is_lispy_filename(original_name)) {
  91                     /* strdup(3) is in Linux and *BSD. If you port
  92                      * somewhere else that doesn't have it, it's easy
  93                      * to reimplement. */
  94                     char* dup_name = strdup(original_name);
  95                     if (!dup_name) { /* if strdup failure */
  96                         goto dtors;
  97                     }
  98                     if (voidacc_acc(&va, dup_name)) { /* if acc failure */
  99                         goto dtors;
 100                     }
 101                 }
 102             }
 103             result = (char**)voidacc_give_away_result(&va);
 104         }
 105
 106     dtors:
 107         voidacc_dtor(&va);
 108         /* ignoring closedir(3) return code, since what could we do?
 109          *
 110          * "Never ask questions you don't want to know the answer to."
 111          * -- William Irving Zumwalt (Rich Cook, _The Wizardry Quested_) */
 112         closedir(dir_ptr);
 113     }
 114
 115     return result;
 116 }
 117
 118 /* Free a result returned by alloc_directory_lispy_filenames(). */
 119 void
 120 free_directory_lispy_filenames(char** directory_lispy_filenames)
 121 {
 122     char** p;
 123
 124     /* Free the strings. */
 125     for (p = directory_lispy_filenames; *p; ++p) {
 126         free(*p);
 127     }
 128
 129     /* Free the table of strings. */
 130     free(directory_lispy_filenames);
 131 }
 132 \f
 133 /*
 134  * readlink(2) stuff
 135  */
 136
 137 #ifndef LISP_FEATURE_WIN32
 138 /* a wrapped version of readlink(2):
 139  *   -- If path isn't a symlink, or is a broken symlink, return 0.
 140  *   -- If path is a symlink, return a newly allocated string holding
 141  *      the thing it's linked to. */
 142 char *
 143 wrapped_readlink(char *path)
 144 {
 145     int bufsiz = strlen(path) + 16;
 146     while (1) {
 147         char *result = malloc(bufsiz);
 148         int n_read = readlink(path, result, bufsiz);
 149         if (n_read < 0) {
 150             free(result);
 151             return 0;
 152         } else if (n_read < bufsiz) {
 153             result[n_read] = 0;
 154             return result;
 155         } else {
 156             free(result);
 157             bufsiz *= 2;
 158         }
 159     }
 160 }
 161 #endif
 162 \f
 163 /*
 164  * realpath(3), including a wrapper for Windows.
 165  */
 166 char * sb_realpath (char *path)
 167 {
 168 #ifndef LISP_FEATURE_WIN32
 169     char *ret;
 170     int errnum;
 171
 172     if ((ret = calloc(PATH_MAX, sizeof(char))) == NULL)
 173         return NULL;
 174     if (realpath(path, ret) == NULL) {
 175         errnum = errno;
 176         free(ret);
 177         errno = errnum;
 178         return NULL;
 179     }
 180     return(ret);
 181 #else
 182     char *ret;
 183     char *cp;
 184     int errnum;
 185
 186     if ((ret = calloc(MAX_PATH, sizeof(char))) == NULL)
 187         return NULL;
 188     if (GetFullPathName(path, MAX_PATH, ret, cp) == 0) {
 189         errnum = errno;
 190         free(ret);
 191         errno = errnum;
 192         return NULL;
 193     }
 194     return(ret);
 195 #endif
 196 }
 197 \f
 198 /*
 199  * stat(2) stuff
 200  */
 201
 202 static void
 203 copy_to_stat_wrapper(struct stat_wrapper *to, struct stat *from)
 204 {
 205 #define FROB(stem) to->wrapped_st_##stem = from->st_##stem
 206 #ifndef LISP_FEATURE_WIN32
 207 #define FROB2(stem) to->wrapped_st_##stem = from->st_##stem
 208 #else
 209 #define FROB2(stem) to->wrapped_st_##stem = 0;
 210 #endif
 211     FROB(dev);
 212     FROB2(ino);
 213     FROB(mode);
 214     FROB(nlink);
 215     FROB2(uid);
 216     FROB2(gid);
 217     FROB(rdev);
 218     FROB(size);
 219     FROB2(blksize);
 220     FROB2(blocks);
 221     FROB(atime);
 222     FROB(mtime);
 223     FROB(ctime);
 224 #undef FROB
 225 }
 226
 227 int
 228 stat_wrapper(const char *file_name, struct stat_wrapper *buf)
 229 {
 230     struct stat real_buf;
 231     int ret;
 232
 233 #ifdef LISP_FEATURE_WIN32
 234     /*
 235      * Windows won't match the last component of a pathname if there
 236      * is a trailing #\/ or #\\, except if it's <drive>:\ or <drive>:/
 237      * in which case it behaves the other way around. So we remove the
 238      * trailing directory separator unless we are being passed just a
 239      * drive name (e.g. "c:\\").  Some, but not all, of this
 240      * strangeness is documented at Microsoft's support site (as of
 241      * 2006-01-08, at
 242      * <http://support.microsoft.com/default.aspx?scid=kb;en-us;168439>)
 243      */
 244     char file_buf[MAX_PATH];
 245     strcpy(file_buf, file_name);
 246     int len = strlen(file_name);
 247     if (len != 0 && (file_name[len-1] == '/' || file_name[len-1] == '\\') &&
 248         !(len == 3 && file_name[1] == ':' && isalpha(file_name[0])))
 249         file_buf[len-1] = '\0';
 250     file_name = file_buf;
 251 #endif
 252
 253     if ((ret = stat(file_name,&real_buf)) >= 0)
 254         copy_to_stat_wrapper(buf, &real_buf);
 255     return ret;
 256 }
 257
 258 #ifndef LISP_FEATURE_WIN32
 259 int
 260 lstat_wrapper(const char *file_name, struct stat_wrapper *buf)
 261 {
 262     struct stat real_buf;
 263     int ret;
 264     if ((ret = lstat(file_name,&real_buf)) >= 0)
 265         copy_to_stat_wrapper(buf, &real_buf);
 266     return ret;
 267 }
 268 #else
 269 /* cleaner to do it here than in Lisp */
 270 int lstat_wrapper(const char *file_name, struct stat_wrapper *buf)
 271 {
 272     return stat_wrapper(file_name, buf);
 273 }
 274 #endif
 275
 276 int
 277 fstat_wrapper(int filedes, struct stat_wrapper *buf)
 278 {
 279     struct stat real_buf;
 280     int ret;
 281     if ((ret = fstat(filedes,&real_buf)) >= 0)
 282         copy_to_stat_wrapper(buf, &real_buf);
 283     return ret;
 284 }
 285 \f
 286 /* A wrapper for mkstemp(3), for two reasons: (1) mkstemp does not
 287    exist on Windows; (2) by passing down a mode_t, we don't need a
 288    binding to chmod in SB-UNIX, and need not concern ourselves with
 289    umask issues if we want to use mkstemp to make new files in
 290    OPEN. */
 291 int sb_mkstemp (char *template, mode_t mode) {
 292 #ifdef LISP_FEATURE_WIN32
 293 #define PATHNAME_BUFFER_SIZE MAX_PATH
 294 #define MKTEMP _mktemp
 295 #else
 296 #define PATHNAME_BUFFER_SIZE PATH_MAX
 297 #define MKTEMP mktemp
 298 #endif
 299   int fd;
 300   char buf[PATHNAME_BUFFER_SIZE];
 301
 302   while (1) {
 303     /* Fruit fallen from the tree: for people who like
 304        microoptimizations, we might not need to copy the whole
 305        template on every loop, but only the last several characters.
 306        But I didn't feel like testing the boundary cases in Windows's
 307        _mktemp. */
 308     strncpy(buf, template, PATHNAME_BUFFER_SIZE);
 309     buf[PATHNAME_BUFFER_SIZE-1]=0; /* force NULL-termination */
 310     if (MKTEMP(buf)) {
 311       if ((fd=open(buf, O_CREAT|O_EXCL|O_RDWR, mode))!=-1) {
 312         strcpy(template, buf);
 313         return (fd);
 314       } else
 315         if (errno != EEXIST)
 316           return (-1);
 317     } else
 318       return (-1);
 319   }
 320 #undef MKTEMP
 321 #undef PATHNAME_BUFFER_SIZE
 322 }
 323
 324 \f
 325 /*
 326  * getpwuid() stuff
 327  */
 328
 329 #ifndef LISP_FEATURE_WIN32
 330 /* Return a newly-allocated string holding the username for "uid", or
 331  * NULL if there's no such user.
 332  *
 333  * KLUDGE: We also return NULL if malloc() runs out of memory
 334  * (returning strdup() result) since it's not clear how to handle that
 335  * error better. -- WHN 2001-12-28 */
 336 char *
 337 uid_username(int uid)
 338 {
 339     struct passwd *p = getpwuid(uid);
 340     if (p) {
 341         /* The object *p is a static struct which'll be overwritten by
 342          * the next call to getpwuid(), so it'd be unsafe to return
 343          * p->pw_name without copying. */
 344         return strdup(p->pw_name);
 345     } else {
 346         return 0;
 347     }
 348 }
 349
 350 char *
 351 uid_homedir(uid_t uid)
 352 {
 353     struct passwd *p = getpwuid(uid);
 354     if(p) {
 355         /* Let's be careful about this, shall we? */
 356         size_t len = strlen(p->pw_dir);
 357         if (p->pw_dir[len-1] == '/') {
 358             return strdup(p->pw_dir);
 359         } else {
 360             char *result = malloc(len + 2);
 361             if (result) {
 362                 unsigned int nchars = sprintf(result,"%s/",p->pw_dir);
 363                 if (nchars == len + 1) {
 364                     return result;
 365                 } else {
 366                     return 0;
 367                 }
 368             } else {
 369                 return 0;
 370             }
 371         }
 372     } else {
 373         return 0;
 374     }
 375 }
 376 #endif /* !LISP_FEATURE_WIN32 */
 377 \f
 378 /*
 379  * functions to get miscellaneous C-level variables
 380  *
 381  * (Doing this by calling functions lets us borrow the smarts of the C
 382  * linker, so that things don't blow up when libc versions and thus
 383  * variable locations change between compile time and run time.)
 384  */
 385
 386 char **
 387 wrapped_environ()
 388 {
 389     return environ;
 390 }
 391
 392 #ifdef LISP_FEATURE_WIN32
 393 #include <windows.h>
 394 #include <time.h>
 395 /*
 396  * faked-up implementation of select(). Right now just enough to get through
 397  * second genesis.
 398  */
 399 int select(int top_fd, DWORD *read_set, DWORD *write_set, DWORD *except_set, time_t *timeout)
 400 {
 401     /*
 402      * FIXME: Going forward, we may want to use MsgWaitForMultipleObjects
 403      * in order to support a windows message loop inside serve-event.
 404      */
 405     HANDLE handles[MAXIMUM_WAIT_OBJECTS];
 406     int fds[MAXIMUM_WAIT_OBJECTS];
 407     int num_handles;
 408     int i;
 409     DWORD retval;
 410     int polling_write;
 411     DWORD win_timeout;
 412
 413     num_handles = 0;
 414     polling_write = 0;
 415     for (i = 0; i < top_fd; i++) {
 416         if (except_set) except_set[i >> 5] = 0;
 417         if (write_set && (write_set[i >> 5] & (1 << (i & 31)))) polling_write = 1;
 418         if (read_set[i >> 5] & (1 << (i & 31))) {
 419             read_set[i >> 5] &= ~(1 << (i & 31));
 420             fds[num_handles] = i;
 421             handles[num_handles++] = (HANDLE) _get_osfhandle(i);
 422         }
 423     }
 424
 425     win_timeout = INFINITE;
 426     if (timeout) win_timeout = (timeout[0] * 1000) + timeout[1];
 427
 428     /* Last parameter here is timeout in milliseconds. */
 429     /* retval = WaitForMultipleObjects(num_handles, handles, 0, INFINITE); */
 430     retval = WaitForMultipleObjects(num_handles, handles, 0, win_timeout);
 431
 432     if (retval < WAIT_ABANDONED) {
 433         /* retval, at this point, is the index of the single live HANDLE/fd. */
 434         read_set[fds[retval] >> 5] |= (1 << (fds[retval] & 31));
 435         return 1;
 436     }
 437     return polling_write;
 438 }
 439
 440 /*
 441  * Windows doesn't have gettimeofday(), and we need it for the compiler,
 442  * for serve-event, and for a couple other things. We don't need a timezone
 443  * yet, however, and the closest we can easily get to a timeval is the
 444  * seconds part. So that's what we do.
 445  */
 446 int gettimeofday(long *timeval, long *timezone)
 447 {
 448     timeval[0] = time(NULL);
 449     timeval[1] = 0;
 450
 451     return 0;
 452 }
 453 #endif
 454
 455
 456 /* We will need to define these things or their equivalents for Win32
 457    eventually, but for now let's get it working for everyone else. */
 458 #ifndef LISP_FEATURE_WIN32
 459 /* From SB-BSD-SOCKETS, to get h_errno */
 460 int get_h_errno()
 461 {
 462     return h_errno;
 463 }
 464
 465 /* From SB-POSIX, wait-macros */
 466 int wifexited(int status) {
 467     return WIFEXITED(status);
 468 }
 469 int wexitstatus(int status) {
 470     return WEXITSTATUS(status);
 471 }
 472 int wifsignaled(int status) {
 473     return WIFSIGNALED(status);
 474 }
 475 int wtermsig(int status) {
 476     return WTERMSIG(status);
 477 }
 478 int wifstopped(int status) {
 479     return WIFSTOPPED(status);
 480 }
 481 int wstopsig(int status) {
 482     return WSTOPSIG(status);
 483 }
 484 /* FIXME: POSIX also defines WIFCONTINUED, but that appears not to
 485    exist on at least Linux... */
 486 #endif  /* !LISP_FEATURE_WIN32 */
 487
 488 /* From SB-POSIX, stat-macros */
 489 int s_isreg(mode_t mode)
 490 {
 491     return S_ISREG(mode);
 492 }
 493 int s_isdir(mode_t mode)
 494 {
 495     return S_ISDIR(mode);
 496 }
 497 int s_ischr(mode_t mode)
 498 {
 499     return S_ISCHR(mode);
 500 }
 501 int s_isblk(mode_t mode)
 502 {
 503     return S_ISBLK(mode);
 504 }
 505 int s_isfifo(mode_t mode)
 506 {
 507     return S_ISFIFO(mode);
 508 }
 509 #ifndef LISP_FEATURE_WIN32
 510 int s_islnk(mode_t mode)
 511 {
 512 #ifdef S_ISLNK
 513     return S_ISLNK(mode);
 514 #else
 515     return ((mode & S_IFMT) == S_IFLNK);
 516 #endif
 517 }
 518 int s_issock(mode_t mode)
 519 {
 520 #ifdef S_ISSOCK
 521     return S_ISSOCK(mode);
 522 #else
 523     return ((mode & S_IFMT) == S_IFSOCK);
 524 #endif
 525 }
 526 #endif /* !LISP_FEATURE_WIN32 */