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 \f
  66 /*
  67  * readlink(2) stuff
  68  */
  69
  70 #ifndef LISP_FEATURE_WIN32
  71 /* a wrapped version of readlink(2):
  72  *   -- If path isn't a symlink, or is a broken symlink, return 0.
  73  *   -- If path is a symlink, return a newly allocated string holding
  74  *      the thing it's linked to. */
  75 char *
  76 wrapped_readlink(char *path)
  77 {
  78     int bufsiz = strlen(path) + 16;
  79     while (1) {
  80         char *result = malloc(bufsiz);
  81         int n_read = readlink(path, result, bufsiz);
  82         if (n_read < 0) {
  83             free(result);
  84             return 0;
  85         } else if (n_read < bufsiz) {
  86             result[n_read] = 0;
  87             return result;
  88         } else {
  89             free(result);
  90             bufsiz *= 2;
  91         }
  92     }
  93 }
  94 #endif
  95 \f
  96 /*
  97  * realpath(3), including a wrapper for Windows.
  98  */
  99 char * sb_realpath (char *path)
 100 {
 101 #ifndef LISP_FEATURE_WIN32
 102     char *ret;
 103     int errnum;
 104
 105     if ((ret = calloc(PATH_MAX, sizeof(char))) == NULL)
 106         return NULL;
 107     if (realpath(path, ret) == NULL) {
 108         errnum = errno;
 109         free(ret);
 110         errno = errnum;
 111         return NULL;
 112     }
 113     return(ret);
 114 #else
 115     char *ret;
 116     char *cp;
 117     int errnum;
 118
 119     if ((ret = calloc(MAX_PATH, sizeof(char))) == NULL)
 120         return NULL;
 121     if (GetFullPathName(path, MAX_PATH, ret, &cp) == 0) {
 122         errnum = errno;
 123         free(ret);
 124         errno = errnum;
 125         return NULL;
 126     }
 127     return(ret);
 128 #endif
 129 }
 130 \f
 131 /* readdir, closedir, and dirent name accessor. The first three are not strictly
 132  * necessary, but should save us some #!+netbsd in the build, and this also allows
 133  * building Windows versions using the non-ANSI variants of FindFirstFile &co
 134  * under the same API. (Use a structure that appends the handle to the WIN32_FIND_DATA
 135  * as the return value from sb_opendir, on sb_readdir grab the name from the previous
 136  * call and save the new one.) Nikodemus thought he would have to do that to support
 137  * DIRECTORY on UNC paths, but turns out opendir &co do TRT on Windows already -- so
 138  * leaving that bit of tedium for a later date, once we figure out the whole *A vs. *W
 139  * issue out properly. ...FIXME, obviously, as per above.
 140  *
 141  * Once that is done, the lisp side functions are best named OS-OPENDIR, etc.
 142  */
 143 extern DIR *
 144 sb_opendir(char * name)
 145 {
 146     return opendir(name);
 147 }
 148
 149 extern struct dirent *
 150 sb_readdir(DIR * dirp)
 151 {
 152     return readdir(dirp);
 153 }
 154
 155 extern int
 156 sb_closedir(DIR * dirp)
 157 {
 158     return closedir(dirp);
 159 }
 160
 161 extern char *
 162 sb_dirent_name(struct dirent * ent)
 163 {
 164     return ent->d_name;
 165 }
 166 \f
 167 /*
 168  * stat(2) stuff
 169  */
 170
 171 static void
 172 copy_to_stat_wrapper(struct stat_wrapper *to, struct stat *from)
 173 {
 174 #define FROB(stem) to->wrapped_st_##stem = from->st_##stem
 175 #ifndef LISP_FEATURE_WIN32
 176 #define FROB2(stem) to->wrapped_st_##stem = from->st_##stem
 177 #else
 178 #define FROB2(stem) to->wrapped_st_##stem = 0;
 179 #endif
 180     FROB(dev);
 181     FROB2(ino);
 182     FROB(mode);
 183     FROB(nlink);
 184     FROB2(uid);
 185     FROB2(gid);
 186     FROB(rdev);
 187     FROB(size);
 188     FROB2(blksize);
 189     FROB2(blocks);
 190     FROB(atime);
 191     FROB(mtime);
 192     FROB(ctime);
 193 #undef FROB
 194 }
 195
 196 int
 197 stat_wrapper(const char *file_name, struct stat_wrapper *buf)
 198 {
 199     struct stat real_buf;
 200     int ret;
 201
 202 #ifdef LISP_FEATURE_WIN32
 203     /*
 204      * Windows won't match the last component of a pathname if there
 205      * is a trailing #\/ or #\\, except if it's <drive>:\ or <drive>:/
 206      * in which case it behaves the other way around. So we remove the
 207      * trailing directory separator unless we are being passed just a
 208      * drive name (e.g. "c:\\").  Some, but not all, of this
 209      * strangeness is documented at Microsoft's support site (as of
 210      * 2006-01-08, at
 211      * <http://support.microsoft.com/default.aspx?scid=kb;en-us;168439>)
 212      */
 213     char file_buf[MAX_PATH];
 214     strcpy(file_buf, file_name);
 215     int len = strlen(file_name);
 216     if (len != 0 && (file_name[len-1] == '/' || file_name[len-1] == '\\') &&
 217         !(len == 3 && file_name[1] == ':' && isalpha(file_name[0])))
 218         file_buf[len-1] = '\0';
 219     file_name = file_buf;
 220 #endif
 221
 222     if ((ret = stat(file_name,&real_buf)) >= 0)
 223         copy_to_stat_wrapper(buf, &real_buf);
 224     return ret;
 225 }
 226
 227 #ifndef LISP_FEATURE_WIN32
 228 int
 229 lstat_wrapper(const char *file_name, struct stat_wrapper *buf)
 230 {
 231     struct stat real_buf;
 232     int ret;
 233     if ((ret = lstat(file_name,&real_buf)) >= 0)
 234         copy_to_stat_wrapper(buf, &real_buf);
 235     return ret;
 236 }
 237 #else
 238 /* cleaner to do it here than in Lisp */
 239 int lstat_wrapper(const char *file_name, struct stat_wrapper *buf)
 240 {
 241     return stat_wrapper(file_name, buf);
 242 }
 243 #endif
 244
 245 int
 246 fstat_wrapper(int filedes, struct stat_wrapper *buf)
 247 {
 248     struct stat real_buf;
 249     int ret;
 250     if ((ret = fstat(filedes,&real_buf)) >= 0)
 251         copy_to_stat_wrapper(buf, &real_buf);
 252     return ret;
 253 }
 254 \f
 255 /* A wrapper for mkstemp(3), for two reasons: (1) mkstemp does not
 256    exist on Windows; (2) by passing down a mode_t, we don't need a
 257    binding to chmod in SB-UNIX, and need not concern ourselves with
 258    umask issues if we want to use mkstemp to make new files in
 259    OPEN. */
 260 int sb_mkstemp (char *template, mode_t mode) {
 261 #ifdef LISP_FEATURE_WIN32
 262 #define PATHNAME_BUFFER_SIZE MAX_PATH
 263 #define MKTEMP _mktemp
 264 #else
 265 #define PATHNAME_BUFFER_SIZE PATH_MAX
 266 #define MKTEMP mktemp
 267 #endif
 268   int fd;
 269   char buf[PATHNAME_BUFFER_SIZE];
 270
 271   while (1) {
 272     /* Fruit fallen from the tree: for people who like
 273        microoptimizations, we might not need to copy the whole
 274        template on every loop, but only the last several characters.
 275        But I didn't feel like testing the boundary cases in Windows's
 276        _mktemp. */
 277     strncpy(buf, template, PATHNAME_BUFFER_SIZE);
 278     buf[PATHNAME_BUFFER_SIZE-1]=0; /* force NULL-termination */
 279     if (MKTEMP(buf)) {
 280       if ((fd=open(buf, O_CREAT|O_EXCL|O_RDWR, mode))!=-1) {
 281         strcpy(template, buf);
 282         return (fd);
 283       } else
 284         if (errno != EEXIST)
 285           return (-1);
 286     } else
 287       return (-1);
 288   }
 289 #undef MKTEMP
 290 #undef PATHNAME_BUFFER_SIZE
 291 }
 292
 293 \f
 294 /*
 295  * getpwuid() stuff
 296  */
 297
 298 #ifndef LISP_FEATURE_WIN32
 299 /* Return a newly-allocated string holding the username for "uid", or
 300  * NULL if there's no such user.
 301  *
 302  * KLUDGE: We also return NULL if malloc() runs out of memory
 303  * (returning strdup() result) since it's not clear how to handle that
 304  * error better. -- WHN 2001-12-28 */
 305 char *
 306 uid_username(int uid)
 307 {
 308     struct passwd *p = getpwuid(uid);
 309     if (p) {
 310         /* The object *p is a static struct which'll be overwritten by
 311          * the next call to getpwuid(), so it'd be unsafe to return
 312          * p->pw_name without copying. */
 313         return strdup(p->pw_name);
 314     } else {
 315         return 0;
 316     }
 317 }
 318
 319 char *
 320 passwd_homedir(struct passwd *p)
 321 {
 322     if (p) {
 323         /* Let's be careful about this, shall we? */
 324         size_t len = strlen(p->pw_dir);
 325         if (p->pw_dir[len-1] == '/') {
 326             return strdup(p->pw_dir);
 327         } else {
 328             char *result = malloc(len + 2);
 329             if (result) {
 330                 unsigned int nchars = sprintf(result,"%s/",p->pw_dir);
 331                 if (nchars == len + 1) {
 332                     return result;
 333                 } else {
 334                     return 0;
 335                 }
 336             } else {
 337                 return 0;
 338             }
 339         }
 340     } else {
 341         return 0;
 342     }
 343 }
 344
 345 char *
 346 user_homedir(char *name)
 347 {
 348     return passwd_homedir(getpwnam(name));
 349 }
 350
 351 char *
 352 uid_homedir(uid_t uid)
 353 {
 354     return passwd_homedir(getpwuid(uid));
 355 }
 356 #endif /* !LISP_FEATURE_WIN32 */
 357 \f
 358 /*
 359  * functions to get miscellaneous C-level variables
 360  *
 361  * (Doing this by calling functions lets us borrow the smarts of the C
 362  * linker, so that things don't blow up when libc versions and thus
 363  * variable locations change between compile time and run time.)
 364  */
 365
 366 char **
 367 wrapped_environ()
 368 {
 369     return environ;
 370 }
 371
 372 #ifdef LISP_FEATURE_WIN32
 373 #include <windows.h>
 374 #include <time.h>
 375 /*
 376  * faked-up implementation of select(). Right now just enough to get through
 377  * second genesis.
 378  */
 379 int select(int top_fd, DWORD *read_set, DWORD *write_set, DWORD *except_set, time_t *timeout)
 380 {
 381     /*
 382      * FIXME: Going forward, we may want to use MsgWaitForMultipleObjects
 383      * in order to support a windows message loop inside serve-event.
 384      */
 385     HANDLE handles[MAXIMUM_WAIT_OBJECTS];
 386     int fds[MAXIMUM_WAIT_OBJECTS];
 387     int num_handles;
 388     int i;
 389     DWORD retval;
 390     int polling_write;
 391     DWORD win_timeout;
 392
 393     num_handles = 0;
 394     polling_write = 0;
 395     for (i = 0; i < top_fd; i++) {
 396         if (except_set) except_set[i >> 5] = 0;
 397         if (write_set && (write_set[i >> 5] & (1 << (i & 31)))) polling_write = 1;
 398         if (read_set[i >> 5] & (1 << (i & 31))) {
 399             read_set[i >> 5] &= ~(1 << (i & 31));
 400             fds[num_handles] = i;
 401             handles[num_handles++] = (HANDLE) _get_osfhandle(i);
 402         }
 403     }
 404
 405     win_timeout = INFINITE;
 406     if (timeout) win_timeout = (timeout[0] * 1000) + timeout[1];
 407
 408     /* Last parameter here is timeout in milliseconds. */
 409     /* retval = WaitForMultipleObjects(num_handles, handles, 0, INFINITE); */
 410     retval = WaitForMultipleObjects(num_handles, handles, 0, win_timeout);
 411
 412     if (retval < WAIT_ABANDONED) {
 413         /* retval, at this point, is the index of the single live HANDLE/fd. */
 414         read_set[fds[retval] >> 5] |= (1 << (fds[retval] & 31));
 415         return 1;
 416     }
 417     return polling_write;
 418 }
 419
 420 /*
 421  * Windows doesn't have gettimeofday(), and we need it for the compiler,
 422  * for serve-event, and for a couple other things. We don't need a timezone
 423  * yet, however, and the closest we can easily get to a timeval is the
 424  * seconds part. So that's what we do.
 425  */
 426 #define UNIX_EPOCH_FILETIME 116444736000000000ULL
 427
 428 int gettimeofday(long *timeval, long *timezone)
 429 {
 430     FILETIME ft;
 431     ULARGE_INTEGER uft;
 432     GetSystemTimeAsFileTime(&ft);
 433     uft.LowPart = ft.dwLowDateTime;
 434     uft.HighPart = ft.dwHighDateTime;
 435     uft.QuadPart -= UNIX_EPOCH_FILETIME;
 436     timeval[0] = uft.QuadPart / 10000000;
 437     timeval[1] = (uft.QuadPart % 10000000)/10;
 438
 439     return 0;
 440 }
 441 #endif
 442
 443
 444 /* We will need to define these things or their equivalents for Win32
 445    eventually, but for now let's get it working for everyone else. */
 446 #ifndef LISP_FEATURE_WIN32
 447 /* From SB-BSD-SOCKETS, to get h_errno */
 448 int get_h_errno()
 449 {
 450     return h_errno;
 451 }
 452
 453 /* From SB-POSIX, wait-macros */
 454 int wifexited(int status) {
 455     return WIFEXITED(status);
 456 }
 457 int wexitstatus(int status) {
 458     return WEXITSTATUS(status);
 459 }
 460 int wifsignaled(int status) {
 461     return WIFSIGNALED(status);
 462 }
 463 int wtermsig(int status) {
 464     return WTERMSIG(status);
 465 }
 466 int wifstopped(int status) {
 467     return WIFSTOPPED(status);
 468 }
 469 int wstopsig(int status) {
 470     return WSTOPSIG(status);
 471 }
 472 /* FIXME: POSIX also defines WIFCONTINUED, but that appears not to
 473    exist on at least Linux... */
 474 #endif  /* !LISP_FEATURE_WIN32 */
 475
 476 /* From SB-POSIX, stat-macros */
 477 int s_isreg(mode_t mode)
 478 {
 479     return S_ISREG(mode);
 480 }
 481 int s_isdir(mode_t mode)
 482 {
 483     return S_ISDIR(mode);
 484 }
 485 int s_ischr(mode_t mode)
 486 {
 487     return S_ISCHR(mode);
 488 }
 489 int s_isblk(mode_t mode)
 490 {
 491     return S_ISBLK(mode);
 492 }
 493 int s_isfifo(mode_t mode)
 494 {
 495     return S_ISFIFO(mode);
 496 }
 497 #ifndef LISP_FEATURE_WIN32
 498 int s_islnk(mode_t mode)
 499 {
 500 #ifdef S_ISLNK
 501     return S_ISLNK(mode);
 502 #else
 503     return ((mode & S_IFMT) == S_IFLNK);
 504 #endif
 505 }
 506 int s_issock(mode_t mode)
 507 {
 508 #ifdef S_ISSOCK
 509     return S_ISSOCK(mode);
 510 #else
 511     return ((mode & S_IFMT) == S_IFSOCK);
 512 #endif
 513 }
 514 #endif /* !LISP_FEATURE_WIN32 */