liblua/liolib.c

   1 /*
   2 ** $Id: liolib.c,v 2.111 2013/03/21 13:57:27 roberto Exp $
   3 ** Standard I/O (and system) library
   4 ** See Copyright Notice in lua.h
   5 */
   6
   7
   8 /*
   9 ** POSIX idiosyncrasy!
  10 ** This definition must come before the inclusion of 'stdio.h'; it
  11 ** should not affect non-POSIX systems
  12 */
  13 #if !defined(_FILE_OFFSET_BITS)
  14 #define _FILE_OFFSET_BITS 64
  15 #endif
  16
  17
  18 #include <errno.h>
  19 #include <stdio.h>
  20 #include <stdlib.h>
  21 #include <string.h>
  22
  23 #define liolib_c
  24 #define LUA_LIB
  25
  26 #include "lua.h"
  27
  28 #include "lauxlib.h"
  29 #include "lualib.h"
  30
  31
  32 #if !defined(lua_checkmode)
  33
  34 /*
  35 ** Check whether 'mode' matches '[rwa]%+?b?'.
  36 ** Change this macro to accept other modes for 'fopen' besides
  37 ** the standard ones.
  38 */
  39 #define lua_checkmode(mode) \
  40         (*mode != '\0' && strchr("rwa", *(mode++)) != NULL &&   \
  41         (*mode != '+' || ++mode) &&  /* skip if char is '+' */  \
  42         (*mode != 'b' || ++mode) &&  /* skip if char is 'b' */  \
  43         (*mode == '\0'))
  44
  45 #endif
  46
  47 /*
  48 ** {======================================================
  49 ** lua_popen spawns a new process connected to the current
  50 ** one through the file streams.
  51 ** =======================================================
  52 */
  53
  54 #if !defined(lua_popen) /* { */
  55
  56 #if defined(LUA_USE_POPEN)      /* { */
  57
  58 #define lua_popen(L,c,m)        ((void)L, fflush(NULL), popen(c,m))
  59 #define lua_pclose(L,file)      ((void)L, pclose(file))
  60
  61 #elif defined(LUA_WIN)          /* }{ */
  62
  63 #define lua_popen(L,c,m)                ((void)L, _popen(c,m))
  64 #define lua_pclose(L,file)              ((void)L, _pclose(file))
  65
  66
  67 #else                           /* }{ */
  68
  69 #define lua_popen(L,c,m)                ((void)((void)c, m),  \
  70                 luaL_error(L, LUA_QL("popen") " not supported"), (FILE*)0)
  71 #define lua_pclose(L,file)              ((void)((void)L, file), -1)
  72
  73
  74 #endif                          /* } */
  75
  76 #endif                  /* } */
  77
  78 /* }====================================================== */
  79
  80
  81 /*
  82 ** {======================================================
  83 ** lua_fseek/lua_ftell: configuration for longer offsets
  84 ** =======================================================
  85 */
  86
  87 #if !defined(lua_fseek) /* { */
  88
  89 #if defined(LUA_USE_POSIX)
  90
  91 #define l_fseek(f,o,w)          fseeko(f,o,w)
  92 #define l_ftell(f)              ftello(f)
  93 #define l_seeknum               off_t
  94
  95 #elif defined(LUA_WIN) && !defined(_CRTIMP_TYPEINFO) \
  96    && defined(_MSC_VER) && (_MSC_VER >= 1400)
  97 /* Windows (but not DDK) and Visual C++ 2005 or higher */
  98
  99 #define l_fseek(f,o,w)          _fseeki64(f,o,w)
 100 #define l_ftell(f)              _ftelli64(f)
 101 #define l_seeknum               __int64
 102
 103 #else
 104
 105 #define l_fseek(f,o,w)          fseek(f,o,w)
 106 #define l_ftell(f)              ftell(f)
 107 #define l_seeknum               long
 108
 109 #endif
 110
 111 #endif                  /* } */
 112
 113 /* }====================================================== */
 114
 115
 116 #define IO_PREFIX       "_IO_"
 117 #define IO_INPUT        (IO_PREFIX "input")
 118 #define IO_OUTPUT       (IO_PREFIX "output")
 119
 120
 121 typedef luaL_Stream LStream;
 122
 123
 124 #define tolstream(L)    ((LStream *)luaL_checkudata(L, 1, LUA_FILEHANDLE))
 125
 126 #define isclosed(p)     ((p)->closef == NULL)
 127
 128
 129 static int io_type (lua_State *L) {
 130   LStream *p;
 131   luaL_checkany(L, 1);
 132   p = (LStream *)luaL_testudata(L, 1, LUA_FILEHANDLE);
 133   if (p == NULL)
 134     lua_pushnil(L);  /* not a file */
 135   else if (isclosed(p))
 136     lua_pushliteral(L, "closed file");
 137   else
 138     lua_pushliteral(L, "file");
 139   return 1;
 140 }
 141
 142
 143 static int f_tostring (lua_State *L) {
 144   LStream *p = tolstream(L);
 145   if (isclosed(p))
 146     lua_pushliteral(L, "file (closed)");
 147   else
 148     lua_pushfstring(L, "file (%p)", p->f);
 149   return 1;
 150 }
 151
 152
 153 static FILE *tofile (lua_State *L) {
 154   LStream *p = tolstream(L);
 155   if (isclosed(p))
 156     luaL_error(L, "attempt to use a closed file");
 157   lua_assert(p->f);
 158   return p->f;
 159 }
 160
 161
 162 /*
 163 ** When creating file handles, always creates a `closed' file handle
 164 ** before opening the actual file; so, if there is a memory error, the
 165 ** file is not left opened.
 166 */
 167 static LStream *newprefile (lua_State *L) {
 168   LStream *p = (LStream *)lua_newuserdata(L, sizeof(LStream));
 169   p->closef = NULL;  /* mark file handle as 'closed' */
 170   luaL_setmetatable(L, LUA_FILEHANDLE);
 171   return p;
 172 }
 173
 174
 175 static int aux_close (lua_State *L) {
 176   LStream *p = tolstream(L);
 177   lua_CFunction cf = p->closef;
 178   p->closef = NULL;  /* mark stream as closed */
 179   return (*cf)(L);  /* close it */
 180 }
 181
 182
 183 static int io_close (lua_State *L) {
 184   if (lua_isnone(L, 1))  /* no argument? */
 185     lua_getfield(L, LUA_REGISTRYINDEX, IO_OUTPUT);  /* use standard output */
 186   tofile(L);  /* make sure argument is an open stream */
 187   return aux_close(L);
 188 }
 189
 190
 191 static int f_gc (lua_State *L) {
 192   LStream *p = tolstream(L);
 193   if (!isclosed(p) && p->f != NULL)
 194     aux_close(L);  /* ignore closed and incompletely open files */
 195   return 0;
 196 }
 197
 198
 199 /*
 200 ** function to close regular files
 201 */
 202 static int io_fclose (lua_State *L) {
 203   LStream *p = tolstream(L);
 204   int res = fclose(p->f);
 205   return luaL_fileresult(L, (res == 0), NULL);
 206 }
 207
 208
 209 static LStream *newfile (lua_State *L) {
 210   LStream *p = newprefile(L);
 211   p->f = NULL;
 212   p->closef = &io_fclose;
 213   return p;
 214 }
 215
 216
 217 static void opencheck (lua_State *L, const char *fname, const char *mode) {
 218   LStream *p = newfile(L);
 219   p->f = fopen(fname, mode);
 220   if (p->f == NULL)
 221     luaL_error(L, "cannot open file " LUA_QS " (%s)", fname, strerror(errno));
 222 }
 223
 224
 225 static int io_open (lua_State *L) {
 226   const char *filename = luaL_checkstring(L, 1);
 227   const char *mode = luaL_optstring(L, 2, "r");
 228   LStream *p = newfile(L);
 229   const char *md = mode;  /* to traverse/check mode */
 230   luaL_argcheck(L, lua_checkmode(md), 2, "invalid mode");
 231   p->f = fopen(filename, mode);
 232   return (p->f == NULL) ? luaL_fileresult(L, 0, filename) : 1;
 233 }
 234
 235
 236 /*
 237 ** function to close 'popen' files
 238 */
 239 static int io_pclose (lua_State *L) {
 240   LStream *p = tolstream(L);
 241   return luaL_execresult(L, lua_pclose(L, p->f));
 242 }
 243
 244
 245 static int io_popen (lua_State *L) {
 246   const char *filename = luaL_checkstring(L, 1);
 247   const char *mode = luaL_optstring(L, 2, "r");
 248   LStream *p = newprefile(L);
 249   p->f = lua_popen(L, filename, mode);
 250   p->closef = &io_pclose;
 251   return (p->f == NULL) ? luaL_fileresult(L, 0, filename) : 1;
 252 }
 253
 254
 255 static int io_tmpfile (lua_State *L) {
 256   LStream *p = newfile(L);
 257   p->f = tmpfile();
 258   return (p->f == NULL) ? luaL_fileresult(L, 0, NULL) : 1;
 259 }
 260
 261
 262 static FILE *getiofile (lua_State *L, const char *findex) {
 263   LStream *p;
 264   lua_getfield(L, LUA_REGISTRYINDEX, findex);
 265   p = (LStream *)lua_touserdata(L, -1);
 266   if (isclosed(p))
 267     luaL_error(L, "standard %s file is closed", findex + strlen(IO_PREFIX));
 268   return p->f;
 269 }
 270
 271
 272 static int g_iofile (lua_State *L, const char *f, const char *mode) {
 273   if (!lua_isnoneornil(L, 1)) {
 274     const char *filename = lua_tostring(L, 1);
 275     if (filename)
 276       opencheck(L, filename, mode);
 277     else {
 278       tofile(L);  /* check that it's a valid file handle */
 279       lua_pushvalue(L, 1);
 280     }
 281     lua_setfield(L, LUA_REGISTRYINDEX, f);
 282   }
 283   /* return current value */
 284   lua_getfield(L, LUA_REGISTRYINDEX, f);
 285   return 1;
 286 }
 287
 288
 289 static int io_input (lua_State *L) {
 290   return g_iofile(L, IO_INPUT, "r");
 291 }
 292
 293
 294 static int io_output (lua_State *L) {
 295   return g_iofile(L, IO_OUTPUT, "w");
 296 }
 297
 298
 299 static int io_readline (lua_State *L);
 300
 301
 302 static void aux_lines (lua_State *L, int toclose) {
 303   int i;
 304   int n = lua_gettop(L) - 1;  /* number of arguments to read */
 305   /* ensure that arguments will fit here and into 'io_readline' stack */
 306   luaL_argcheck(L, n <= LUA_MINSTACK - 3, LUA_MINSTACK - 3, "too many options");
 307   lua_pushvalue(L, 1);  /* file handle */
 308   lua_pushinteger(L, n);  /* number of arguments to read */
 309   lua_pushboolean(L, toclose);  /* close/not close file when finished */
 310   for (i = 1; i <= n; i++) lua_pushvalue(L, i + 1);  /* copy arguments */
 311   lua_pushcclosure(L, io_readline, 3 + n);
 312 }
 313
 314
 315 static int f_lines (lua_State *L) {
 316   tofile(L);  /* check that it's a valid file handle */
 317   aux_lines(L, 0);
 318   return 1;
 319 }
 320
 321
 322 static int io_lines (lua_State *L) {
 323   int toclose;
 324   if (lua_isnone(L, 1)) lua_pushnil(L);  /* at least one argument */
 325   if (lua_isnil(L, 1)) {  /* no file name? */
 326     lua_getfield(L, LUA_REGISTRYINDEX, IO_INPUT);  /* get default input */
 327     lua_replace(L, 1);  /* put it at index 1 */
 328     tofile(L);  /* check that it's a valid file handle */
 329     toclose = 0;  /* do not close it after iteration */
 330   }
 331   else {  /* open a new file */
 332     const char *filename = luaL_checkstring(L, 1);
 333     opencheck(L, filename, "r");
 334     lua_replace(L, 1);  /* put file at index 1 */
 335     toclose = 1;  /* close it after iteration */
 336   }
 337   aux_lines(L, toclose);
 338   return 1;
 339 }
 340
 341
 342 /*
 343 ** {======================================================
 344 ** READ
 345 ** =======================================================
 346 */
 347
 348
 349 static int read_number (lua_State *L, FILE *f) {
 350   lua_Number d;
 351   if (fscanf(f, LUA_NUMBER_SCAN, &d) == 1) {
 352     lua_pushnumber(L, d);
 353     return 1;
 354   }
 355   else {
 356    lua_pushnil(L);  /* "result" to be removed */
 357    return 0;  /* read fails */
 358   }
 359 }
 360
 361
 362 static int test_eof (lua_State *L, FILE *f) {
 363   int c = getc(f);
 364   ungetc(c, f);
 365   lua_pushlstring(L, NULL, 0);
 366   return (c != EOF);
 367 }
 368
 369
 370 static int read_line (lua_State *L, FILE *f, int chop) {
 371   luaL_Buffer b;
 372   luaL_buffinit(L, &b);
 373   for (;;) {
 374     size_t l;
 375     char *p = luaL_prepbuffer(&b);
 376     if (fgets(p, LUAL_BUFFERSIZE, f) == NULL) {  /* eof? */
 377       luaL_pushresult(&b);  /* close buffer */
 378       return (lua_rawlen(L, -1) > 0);  /* check whether read something */
 379     }
 380     l = strlen(p);
 381     if (l == 0 || p[l-1] != '\n')
 382       luaL_addsize(&b, l);
 383     else {
 384       luaL_addsize(&b, l - chop);  /* chop 'eol' if needed */
 385       luaL_pushresult(&b);  /* close buffer */
 386       return 1;  /* read at least an `eol' */
 387     }
 388   }
 389 }
 390
 391
 392 #define MAX_SIZE_T      (~(size_t)0)
 393
 394 static void read_all (lua_State *L, FILE *f) {
 395   size_t rlen = LUAL_BUFFERSIZE;  /* how much to read in each cycle */
 396   luaL_Buffer b;
 397   luaL_buffinit(L, &b);
 398   for (;;) {
 399     char *p = luaL_prepbuffsize(&b, rlen);
 400     size_t nr = fread(p, sizeof(char), rlen, f);
 401     luaL_addsize(&b, nr);
 402     if (nr < rlen) break;  /* eof? */
 403     else if (rlen <= (MAX_SIZE_T / 4))  /* avoid buffers too large */
 404       rlen *= 2;  /* double buffer size at each iteration */
 405   }
 406   luaL_pushresult(&b);  /* close buffer */
 407 }
 408
 409
 410 static int read_chars (lua_State *L, FILE *f, size_t n) {
 411   size_t nr;  /* number of chars actually read */
 412   char *p;
 413   luaL_Buffer b;
 414   luaL_buffinit(L, &b);
 415   p = luaL_prepbuffsize(&b, n);  /* prepare buffer to read whole block */
 416   nr = fread(p, sizeof(char), n, f);  /* try to read 'n' chars */
 417   luaL_addsize(&b, nr);
 418   luaL_pushresult(&b);  /* close buffer */
 419   return (nr > 0);  /* true iff read something */
 420 }
 421
 422
 423 static int g_read (lua_State *L, FILE *f, int first) {
 424   int nargs = lua_gettop(L) - 1;
 425   int success;
 426   int n;
 427   clearerr(f);
 428   if (nargs == 0) {  /* no arguments? */
 429     success = read_line(L, f, 1);
 430     n = first+1;  /* to return 1 result */
 431   }
 432   else {  /* ensure stack space for all results and for auxlib's buffer */
 433     luaL_checkstack(L, nargs+LUA_MINSTACK, "too many arguments");
 434     success = 1;
 435     for (n = first; nargs-- && success; n++) {
 436       if (lua_type(L, n) == LUA_TNUMBER) {
 437         size_t l = (size_t)lua_tointeger(L, n);
 438         success = (l == 0) ? test_eof(L, f) : read_chars(L, f, l);
 439       }
 440       else {
 441         const char *p = lua_tostring(L, n);
 442         luaL_argcheck(L, p && p[0] == '*', n, "invalid option");
 443         switch (p[1]) {
 444           case 'n':  /* number */
 445             success = read_number(L, f);
 446             break;
 447           case 'l':  /* line */
 448             success = read_line(L, f, 1);
 449             break;
 450           case 'L':  /* line with end-of-line */
 451             success = read_line(L, f, 0);
 452             break;
 453           case 'a':  /* file */
 454             read_all(L, f);  /* read entire file */
 455             success = 1; /* always success */
 456             break;
 457           default:
 458             return luaL_argerror(L, n, "invalid format");
 459         }
 460       }
 461     }
 462   }
 463   if (ferror(f))
 464     return luaL_fileresult(L, 0, NULL);
 465   if (!success) {
 466     lua_pop(L, 1);  /* remove last result */
 467     lua_pushnil(L);  /* push nil instead */
 468   }
 469   return n - first;
 470 }
 471
 472
 473 static int io_read (lua_State *L) {
 474   return g_read(L, getiofile(L, IO_INPUT), 1);
 475 }
 476
 477
 478 static int f_read (lua_State *L) {
 479   return g_read(L, tofile(L), 2);
 480 }
 481
 482
 483 static int io_readline (lua_State *L) {
 484   LStream *p = (LStream *)lua_touserdata(L, lua_upvalueindex(1));
 485   int i;
 486   int n = (int)lua_tointeger(L, lua_upvalueindex(2));
 487   if (isclosed(p))  /* file is already closed? */
 488     return luaL_error(L, "file is already closed");
 489   lua_settop(L , 1);
 490   for (i = 1; i <= n; i++)  /* push arguments to 'g_read' */
 491     lua_pushvalue(L, lua_upvalueindex(3 + i));
 492   n = g_read(L, p->f, 2);  /* 'n' is number of results */
 493   lua_assert(n > 0);  /* should return at least a nil */
 494   if (!lua_isnil(L, -n))  /* read at least one value? */
 495     return n;  /* return them */
 496   else {  /* first result is nil: EOF or error */
 497     if (n > 1) {  /* is there error information? */
 498       /* 2nd result is error message */
 499       return luaL_error(L, "%s", lua_tostring(L, -n + 1));
 500     }
 501     if (lua_toboolean(L, lua_upvalueindex(3))) {  /* generator created file? */
 502       lua_settop(L, 0);
 503       lua_pushvalue(L, lua_upvalueindex(1));
 504       aux_close(L);  /* close it */
 505     }
 506     return 0;
 507   }
 508 }
 509
 510 /* }====================================================== */
 511
 512
 513 static int g_write (lua_State *L, FILE *f, int arg) {
 514   int nargs = lua_gettop(L) - arg;
 515   int status = 1;
 516   for (; nargs--; arg++) {
 517     if (lua_type(L, arg) == LUA_TNUMBER) {
 518       /* optimization: could be done exactly as for strings */
 519       status = status &&
 520           fprintf(f, LUA_NUMBER_FMT, lua_tonumber(L, arg)) > 0;
 521     }
 522     else {
 523       size_t l;
 524       const char *s = luaL_checklstring(L, arg, &l);
 525       status = status && (fwrite(s, sizeof(char), l, f) == l);
 526     }
 527   }
 528   if (status) return 1;  /* file handle already on stack top */
 529   else return luaL_fileresult(L, status, NULL);
 530 }
 531
 532
 533 static int io_write (lua_State *L) {
 534   return g_write(L, getiofile(L, IO_OUTPUT), 1);
 535 }
 536
 537
 538 static int f_write (lua_State *L) {
 539   FILE *f = tofile(L);
 540   lua_pushvalue(L, 1);  /* push file at the stack top (to be returned) */
 541   return g_write(L, f, 2);
 542 }
 543
 544
 545 static int f_seek (lua_State *L) {
 546   static const int mode[] = {SEEK_SET, SEEK_CUR, SEEK_END};
 547   static const char *const modenames[] = {"set", "cur", "end", NULL};
 548   FILE *f = tofile(L);
 549   int op = luaL_checkoption(L, 2, "cur", modenames);
 550   lua_Number p3 = luaL_optnumber(L, 3, 0);
 551   l_seeknum offset = (l_seeknum)p3;
 552   luaL_argcheck(L, (lua_Number)offset == p3, 3,
 553                   "not an integer in proper range");
 554   op = l_fseek(f, offset, mode[op]);
 555   if (op)
 556     return luaL_fileresult(L, 0, NULL);  /* error */
 557   else {
 558     lua_pushnumber(L, (lua_Number)l_ftell(f));
 559     return 1;
 560   }
 561 }
 562
 563
 564 static int f_setvbuf (lua_State *L) {
 565   static const int mode[] = {_IONBF, _IOFBF, _IOLBF};
 566   static const char *const modenames[] = {"no", "full", "line", NULL};
 567   FILE *f = tofile(L);
 568   int op = luaL_checkoption(L, 2, NULL, modenames);
 569   lua_Integer sz = luaL_optinteger(L, 3, LUAL_BUFFERSIZE);
 570   int res = setvbuf(f, NULL, mode[op], sz);
 571   return luaL_fileresult(L, res == 0, NULL);
 572 }
 573
 574
 575
 576 static int io_flush (lua_State *L) {
 577   return luaL_fileresult(L, fflush(getiofile(L, IO_OUTPUT)) == 0, NULL);
 578 }
 579
 580
 581 static int f_flush (lua_State *L) {
 582   return luaL_fileresult(L, fflush(tofile(L)) == 0, NULL);
 583 }
 584
 585
 586 /*
 587 ** functions for 'io' library
 588 */
 589 static const luaL_Reg iolib[] = {
 590   {"close", io_close},
 591   {"flush", io_flush},
 592   {"input", io_input},
 593   {"lines", io_lines},
 594   {"open", io_open},
 595   {"output", io_output},
 596   {"popen", io_popen},
 597   {"read", io_read},
 598   {"tmpfile", io_tmpfile},
 599   {"type", io_type},
 600   {"write", io_write},
 601   {NULL, NULL}
 602 };
 603
 604
 605 /*
 606 ** methods for file handles
 607 */
 608 static const luaL_Reg flib[] = {
 609   {"close", io_close},
 610   {"flush", f_flush},
 611   {"lines", f_lines},
 612   {"read", f_read},
 613   {"seek", f_seek},
 614   {"setvbuf", f_setvbuf},
 615   {"write", f_write},
 616   {"__gc", f_gc},
 617   {"__tostring", f_tostring},
 618   {NULL, NULL}
 619 };
 620
 621
 622 static void createmeta (lua_State *L) {
 623   luaL_newmetatable(L, LUA_FILEHANDLE);  /* create metatable for file handles */
 624   lua_pushvalue(L, -1);  /* push metatable */
 625   lua_setfield(L, -2, "__index");  /* metatable.__index = metatable */
 626   luaL_setfuncs(L, flib, 0);  /* add file methods to new metatable */
 627   lua_pop(L, 1);  /* pop new metatable */
 628 }
 629
 630
 631 /*
 632 ** function to (not) close the standard files stdin, stdout, and stderr
 633 */
 634 static int io_noclose (lua_State *L) {
 635   LStream *p = tolstream(L);
 636   p->closef = &io_noclose;  /* keep file opened */
 637   lua_pushnil(L);
 638   lua_pushliteral(L, "cannot close standard file");
 639   return 2;
 640 }
 641
 642
 643 static void createstdfile (lua_State *L, FILE *f, const char *k,
 644                            const char *fname) {
 645   LStream *p = newprefile(L);
 646   p->f = f;
 647   p->closef = &io_noclose;
 648   if (k != NULL) {
 649     lua_pushvalue(L, -1);
 650     lua_setfield(L, LUA_REGISTRYINDEX, k);  /* add file to registry */
 651   }
 652   lua_setfield(L, -2, fname);  /* add file to module */
 653 }
 654
 655
 656 LUAMOD_API int luaopen_io (lua_State *L) {
 657   luaL_newlib(L, iolib);  /* new module */
 658   createmeta(L);
 659   /* create (and set) default files */
 660   createstdfile(L, stdin, IO_INPUT, "stdin");
 661   createstdfile(L, stdout, IO_OUTPUT, "stdout");
 662   createstdfile(L, stderr, NULL, "stderr");
 663   return 1;
 664 }
 665