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