ls.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * tiny-ls.c version 0.1.0: A minimalist 'ls'
   4  * Copyright (C) 1996 Brian Candler <B.Candler@pobox.com>
   5  *
   6  *  This program is free software; you can redistribute it and/or modify
   7  *  it under the terms of the GNU General Public License as published by
   8  *  the Free Software Foundation; either version 2 of the License, or
   9  *  (at your option) any later version.
  10  *
  11  *  This program is distributed in the hope that it will be useful,
  12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  *  GNU General Public License for more details.
  15  *
  16  *  You should have received a copy of the GNU General Public License
  17  *  along with this program; if not, write to the Free Software
  18  *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  19  */
  20
  21 /*
  22  * To achieve a small memory footprint, this version of 'ls' doesn't do any
  23  * file sorting, and only has the most essential command line switches
  24  * (i.e. the ones I couldn't live without :-) All features which involve
  25  * linking in substantial chunks of libc can be disabled.
  26  *
  27  * Although I don't really want to add new features to this program to
  28  * keep it small, I *am* interested to receive bug fixes and ways to make
  29  * it more portable.
  30  *
  31  * KNOWN BUGS:
  32  * 1. ls -l of a directory doesn't give "total <blocks>" header
  33  * 2. ls of a symlink to a directory doesn't list directory contents
  34  * 3. hidden files can make column width too large
  35  *
  36  * NON-OPTIMAL BEHAVIOUR:
  37  * 1. autowidth reads directories twice
  38  * 2. if you do a short directory listing without filetype characters
  39  *    appended, there's no need to stat each one
  40  * PORTABILITY:
  41  * 1. requires lstat (BSD) - how do you do it without?
  42  */
  43
  44 #define TERMINAL_WIDTH  80              /* use 79 if your terminal has linefold bug */
  45 #define COLUMN_WIDTH    14              /* default if AUTOWIDTH not defined */
  46 #define COLUMN_GAP      2                       /* includes the file type char, if present */
  47 #define HAS_REWINDDIR
  48
  49 /************************************************************************/
  50
  51 #include "internal.h"
  52 #if !defined(__GLIBC__) && (__GLIBC__ >= 2) && (__GLIBC_MINOR__ >= 1)
  53 # include <linux/types.h>
  54 #else
  55 # include <sys/types.h>
  56 #endif
  57 #include <sys/stat.h>
  58 #include <stdio.h>
  59 #include <unistd.h>
  60 #include <dirent.h>
  61 #include <errno.h>
  62 #include <stdio.h>
  63 #ifdef BB_FEATURE_LS_TIMESTAMPS
  64 #include <time.h>
  65 #endif
  66
  67 #define TYPEINDEX(mode) (((mode) >> 12) & 0x0f)
  68 #define TYPECHAR(mode)  ("0pcCd?bB-?l?s???" [TYPEINDEX(mode)])
  69 #ifdef BB_FEATURE_LS_FILETYPES
  70 #define APPCHAR(mode)   ("\0|\0\0/\0\0\0\0\0@\0=\0\0\0" [TYPEINDEX(mode)])
  71 #endif
  72
  73 #define FMT_AUTO        0
  74 #define FMT_LONG        1                       /* one record per line, extended info */
  75 #define FMT_SINGLE      2                       /* one record per line */
  76 #define FMT_ROWS        3                       /* print across rows */
  77 #define FMT_COLUMNS     3                       /* fill columns (same, since we don't sort) */
  78
  79 #define TIME_MOD        0
  80 #define TIME_CHANGE     1
  81 #define TIME_ACCESS     2
  82
  83 #define DISP_FTYPE      1                       /* show character for file type */
  84 #define DISP_EXEC       2                       /* show '*' if regular executable file */
  85 #define DISP_HIDDEN     4                       /* show files starting . (except . and ..) */
  86 #define DISP_DOT        8                       /* show . and .. */
  87 #define DISP_NUMERIC    16              /* numeric uid and gid */
  88 #define DISP_FULLTIME   32              /* show extended time display */
  89 #define DIR_NOLIST      64                      /* show directory as itself, not contents */
  90 #define DISP_DIRNAME    128             /* show directory name (for internal use) */
  91
  92 #ifndef MAJOR
  93 #define MAJOR(dev) (((dev)>>8)&0xff)
  94 #define MINOR(dev) ((dev)&0xff)
  95 #endif
  96
  97 static unsigned char display_fmt = FMT_AUTO;
  98 static unsigned short opts = 0;
  99 static unsigned short column = 0;
 100
 101 #ifdef BB_FEATURE_AUTOWIDTH
 102 static unsigned short terminal_width = 0;
 103 static unsigned short column_width = 0;
 104 static unsigned short toplevel_column_width = 0;
 105 #else
 106 #define terminal_width  TERMINAL_WIDTH
 107 #define column_width    COLUMN_WIDTH
 108 #endif
 109
 110 #ifdef BB_FEATURE_LS_TIMESTAMPS
 111 static unsigned char time_fmt = TIME_MOD;
 112 #endif
 113
 114 #define wr(data,len) fwrite(data, 1, len, stdout)
 115
 116 static void writenum(long val, short minwidth)
 117 {
 118         char scratch[128];
 119
 120         char *p = scratch + sizeof(scratch);
 121         short len = 0;
 122         short neg = (val < 0);
 123
 124         if (neg)
 125                 val = -val;
 126         do
 127                 *--p = (val % 10) + '0', len++, val /= 10;
 128         while (val);
 129         if (neg)
 130                 *--p = '-', len++;
 131         while (len < minwidth)
 132                 *--p = ' ', len++;
 133         wr(p, len);
 134         column += len;
 135 }
 136
 137 static void newline(void)
 138 {
 139         if (column > 0) {
 140                 wr("\n", 1);
 141                 column = 0;
 142         }
 143 }
 144
 145 static void tab(short col)
 146 {
 147         static const char spaces[] = "                ";
 148
 149 #define nspaces ((sizeof spaces)-1)     /* null terminator! */
 150
 151         short n = col - column;
 152
 153         if (n > 0) {
 154                 column = col;
 155                 while (n > nspaces) {
 156                         wr(spaces, nspaces);
 157                         n -= nspaces;
 158                 }
 159                 /* must be 1...(sizeof spaces) left */
 160                 wr(spaces, n);
 161         }
 162 #undef nspaces
 163 }
 164
 165 #ifdef BB_FEATURE_LS_FILETYPES
 166 static char append_char(mode_t mode)
 167 {
 168         if (!(opts & DISP_FTYPE))
 169                 return '\0';
 170         if ((opts & DISP_EXEC) && S_ISREG(mode)
 171                 && (mode & (S_IXUSR | S_IXGRP | S_IXOTH))) return '*';
 172         return APPCHAR(mode);
 173 }
 174 #endif
 175
 176 /**
 177  **
 178  ** Display a file or directory as a single item
 179  ** (in either long or short format)
 180  **
 181  **/
 182
 183 static void list_single(const char *name, struct stat *info,
 184                                                 const char *fullname)
 185 {
 186         char scratch[PATH_MAX + 1];
 187         short len = strlen(name);
 188
 189 #ifdef BB_FEATURE_LS_FILETYPES
 190         char append = append_char(info->st_mode);
 191 #endif
 192
 193         if (display_fmt == FMT_LONG) {
 194                 mode_t mode = info->st_mode;
 195
 196                 newline();
 197                 wr(modeString(mode), 10);
 198                 column = 10;
 199                 writenum((long) info->st_nlink, (short) 5);
 200                 fputs(" ", stdout);
 201 #ifdef BB_FEATURE_LS_USERNAME
 202                 if (!(opts & DISP_NUMERIC)) {
 203                         memset(scratch, 0, sizeof(scratch));
 204                         my_getpwuid(scratch, info->st_uid);
 205                         if (*scratch) {
 206                                 fputs(scratch, stdout);
 207                                 if (strlen(scratch) <= 8)
 208                                         wr("          ", 9 - strlen(scratch));
 209                         } else {
 210                                 writenum((long) info->st_uid, (short) 8);
 211                                 fputs(" ", stdout);
 212                         }
 213                 } else
 214 #endif
 215                 {
 216                         writenum((long) info->st_uid, (short) 8);
 217                         fputs(" ", stdout);
 218                 }
 219 #ifdef BB_FEATURE_LS_USERNAME
 220                 if (!(opts & DISP_NUMERIC)) {
 221                         memset(scratch, 0, sizeof(scratch));
 222                         my_getgrgid(scratch, info->st_gid);
 223                         if (*scratch) {
 224                                 fputs(scratch, stdout);
 225                                 if (strlen(scratch) <= 8)
 226                                         wr("         ", 8 - strlen(scratch));
 227                         } else
 228                                 writenum((long) info->st_gid, (short) 8);
 229                 } else
 230 #endif
 231                         writenum((long) info->st_gid, (short) 8);
 232                 //tab(26);
 233                 if (S_ISBLK(mode) || S_ISCHR(mode)) {
 234                         writenum((long) MAJOR(info->st_rdev), (short) 3);
 235                         fputs(", ", stdout);
 236                         writenum((long) MINOR(info->st_rdev), (short) 3);
 237                 } else
 238                         writenum((long) info->st_size, (short) 8);
 239                 fputs(" ", stdout);
 240                 //tab(32);
 241 #ifdef BB_FEATURE_LS_TIMESTAMPS
 242                 {
 243                         time_t cal;
 244                         char *string;
 245
 246                         switch (time_fmt) {
 247                         case TIME_CHANGE:
 248                                 cal = info->st_ctime;
 249                                 break;
 250                         case TIME_ACCESS:
 251                                 cal = info->st_atime;
 252                                 break;
 253                         default:
 254                                 cal = info->st_mtime;
 255                                 break;
 256                         }
 257                         string = ctime(&cal);
 258                         if (opts & DISP_FULLTIME)
 259                                 wr(string, 24);
 260                         else {
 261                                 time_t age = time(NULL) - cal;
 262
 263                                 wr(string + 4, 7);      /* mmm_dd_ */
 264                                 if (age < 3600L * 24 * 365 / 2 && age > -15 * 60)
 265                                         /* hh:mm if less than 6 months old */
 266                                         wr(string + 11, 5);
 267                                 else
 268                                         /* _yyyy otherwise */
 269                                         wr(string + 19, 5);
 270                         }
 271                         wr(" ", 1);
 272                 }
 273 #else
 274                 fputs("--- -- ----- ", stdout);
 275 #endif
 276                 wr(name, len);
 277                 if (S_ISLNK(mode)) {
 278                         wr(" -> ", 4);
 279                         len = readlink(fullname, scratch, sizeof scratch);
 280                         if (len > 0)
 281                                 fwrite(scratch, 1, len, stdout);
 282 #ifdef BB_FEATURE_LS_FILETYPES
 283                         /* show type of destination */
 284                         if (opts & DISP_FTYPE) {
 285                                 if (!stat(fullname, info)) {
 286                                         append = append_char(info->st_mode);
 287                                         if (append)
 288                                                 fputc(append, stdout);
 289                                 }
 290                         }
 291 #endif
 292                 }
 293 #ifdef BB_FEATURE_LS_FILETYPES
 294                 else if (append)
 295                         wr(&append, 1);
 296 #endif
 297         } else {
 298                 static short nexttab = 0;
 299
 300                 /* sort out column alignment */
 301                 if (column == 0);               /* nothing to do */
 302                 else if (display_fmt == FMT_SINGLE)
 303                         newline();
 304                 else {
 305                         if (nexttab + column_width > terminal_width
 306 #ifndef BB_FEATURE_AUTOWIDTH
 307                                 || nexttab + len >= terminal_width
 308 #endif
 309                                 )
 310                                 newline();
 311                         else
 312                                 tab(nexttab);
 313                 }
 314                 /* work out where next column starts */
 315 #ifdef BB_FEATURE_AUTOWIDTH
 316                 /* we know the calculated width is big enough */
 317                 nexttab = column + column_width + COLUMN_GAP;
 318 #else
 319                 /* might cover more than one fixed-width column */
 320                 nexttab = column;
 321                 do
 322                         nexttab += column_width + COLUMN_GAP;
 323                 while (nexttab < (column + len + COLUMN_GAP));
 324 #endif
 325                 /* now write the data */
 326                 wr(name, len);
 327                 column = column + len;
 328 #ifdef BB_FEATURE_LS_FILETYPES
 329                 if (append)
 330                         wr(&append, 1), column++;
 331 #endif
 332         }
 333 }
 334
 335 /**
 336  **
 337  ** List the given file or directory, expanding a directory
 338  ** to show its contents if required
 339  **
 340  **/
 341
 342 static int list_item(const char *name)
 343 {
 344         struct stat info;
 345         DIR *dir;
 346         struct dirent *entry;
 347         char fullname[MAXNAMLEN + 1], *fnend;
 348
 349         if (lstat(name, &info))
 350                 goto listerr;
 351
 352         if (!S_ISDIR(info.st_mode) || (opts & DIR_NOLIST)) {
 353 #ifdef BB_FEATURE_AUTOWIDTH
 354                 column_width = toplevel_column_width;
 355 #endif
 356                 list_single(name, &info, name);
 357                 return 0;
 358         }
 359
 360         /* Otherwise, it's a directory we want to list the contents of */
 361
 362         if (opts & DISP_DIRNAME) {      /* identify the directory */
 363                 if (column)
 364                         wr("\n\n", 2), column = 0;
 365                 wr(name, strlen(name));
 366                 wr(":\n", 2);
 367         }
 368
 369         dir = opendir(name);
 370         if (!dir)
 371                 goto listerr;
 372 #ifdef BB_FEATURE_AUTOWIDTH
 373         column_width = 0;
 374         while ((entry = readdir(dir)) != NULL) {
 375                 short w = strlen(entry->d_name);
 376
 377                 if (column_width < w)
 378                         column_width = w;
 379         }
 380 #ifdef HAS_REWINDDIR
 381         rewinddir(dir);
 382 #else
 383         closedir(dir);
 384         dir = opendir(name);
 385         if (!dir)
 386                 goto listerr;
 387 #endif
 388 #endif
 389
 390         /* List the contents */
 391
 392         strcpy(fullname, name);         /* *** ignore '.' by itself */
 393         fnend = fullname + strlen(fullname);
 394         if (fnend[-1] != '/')
 395                 *fnend++ = '/';
 396
 397         while ((entry = readdir(dir)) != NULL) {
 398                 const char *en = entry->d_name;
 399
 400                 if (en[0] == '.') {
 401                         if (!en[1] || (en[1] == '.' && !en[2])) {       /* . or .. */
 402                                 if (!(opts & DISP_DOT))
 403                                         continue;
 404                         } else if (!(opts & DISP_HIDDEN))
 405                                 continue;
 406                 }
 407                 /* FIXME: avoid stat if not required */
 408                 strcpy(fnend, entry->d_name);
 409                 if (lstat(fullname, &info))
 410                         goto direrr;            /* (shouldn't fail) */
 411                 list_single(entry->d_name, &info, fullname);
 412         }
 413         closedir(dir);
 414
 415         if (opts & DISP_DIRNAME) {      /* separate the directory */
 416                 if (column) {
 417                         wr("\n", 1);
 418                 }
 419                 wr("\n", 1);
 420                 column = 0;
 421         }
 422
 423         return 0;
 424
 425   direrr:
 426         closedir(dir);
 427   listerr:
 428         newline();
 429         perror(name);
 430         return 1;
 431 }
 432
 433 static const char ls_usage[] = "ls [-1a"
 434 #ifdef BB_FEATURE_LS_TIMESTAMPS
 435         "c"
 436 #endif
 437         "d"
 438 #ifdef BB_FEATURE_LS_TIMESTAMPS
 439         "e"
 440 #endif
 441         "ln"
 442 #ifdef BB_FEATURE_LS_FILETYPES
 443         "p"
 444 #endif
 445 #ifdef BB_FEATURE_LS_TIMESTAMPS
 446         "u"
 447 #endif
 448         "xAC"
 449 #ifdef BB_FEATURE_LS_FILETYPES
 450         "F"
 451 #endif
 452         "] [filenames...]\n\n"
 453         "Options:\n"
 454         "\t-a\tdo not hide entries starting with .\n"
 455 #ifdef BB_FEATURE_LS_TIMESTAMPS
 456         "\t-c\twith -l: show ctime (the time of last\n"
 457     "\t\tmodification of file status information)\n"
 458 #endif
 459         "\t-d\tlist directory entries instead of contents\n"
 460 #ifdef BB_FEATURE_LS_TIMESTAMPS
 461         "\t-e\tlist both full date and full time\n"
 462 #endif
 463         "\t-l\tuse a long listing format\n"
 464         "\t-n\tlist numeric UIDs and GIDs instead of names\n"
 465 #ifdef BB_FEATURE_LS_FILETYPES
 466         "\t-p\tappend indicator (one of /=@|) to entries\n"
 467 #endif
 468 #ifdef BB_FEATURE_LS_TIMESTAMPS
 469         "\t-u\twith -l: show access time (the time of last\n"
 470         "\t\taccess of the file)\n"
 471 #endif
 472         "\t-x\tlist entries by lines instead of by columns\n"
 473         "\t-A\tdo not list implied . and ..\n"
 474         "\t-C\tlist entries by columns\n"
 475 #ifdef BB_FEATURE_LS_FILETYPES
 476         "\t-F\tappend indicator (one of */=@|) to entries\n"
 477 #endif
 478         ;
 479
 480 extern int ls_main(int argc, char **argv)
 481 {
 482         int argi = 1, i;
 483
 484         /* process options */
 485         while (argi < argc && argv[argi][0] == '-') {
 486                 const char *p = &argv[argi][1];
 487
 488                 if (!*p)
 489                         goto print_usage_message;       /* "-" by itself not allowed */
 490                 if (*p == '-') {
 491                         if (!p[1]) {            /* "--" forces end of options */
 492                                 argi++;
 493                                 break;
 494                         }
 495                         /* it's a long option name - we don't support them */
 496                         goto print_usage_message;
 497                 }
 498
 499                 while (*p)
 500                         switch (*p++) {
 501                         case 'l':
 502                                 display_fmt = FMT_LONG;
 503                                 break;
 504                         case '1':
 505                                 display_fmt = FMT_SINGLE;
 506                                 break;
 507                         case 'x':
 508                                 display_fmt = FMT_ROWS;
 509                                 break;
 510                         case 'C':
 511                                 display_fmt = FMT_COLUMNS;
 512                                 break;
 513 #ifdef BB_FEATURE_LS_FILETYPES
 514                         case 'p':
 515                                 opts |= DISP_FTYPE;
 516                                 break;
 517                         case 'F':
 518                                 opts |= DISP_FTYPE | DISP_EXEC;
 519                                 break;
 520 #endif
 521                         case 'A':
 522                                 opts |= DISP_HIDDEN;
 523                                 break;
 524                         case 'a':
 525                                 opts |= DISP_HIDDEN | DISP_DOT;
 526                                 break;
 527                         case 'n':
 528                                 opts |= DISP_NUMERIC;
 529                                 break;
 530                         case 'd':
 531                                 opts |= DIR_NOLIST;
 532                                 break;
 533 #ifdef BB_FEATURE_LS_TIMESTAMPS
 534                         case 'u':
 535                                 time_fmt = TIME_ACCESS;
 536                                 break;
 537                         case 'c':
 538                                 time_fmt = TIME_CHANGE;
 539                                 break;
 540                         case 'e':
 541                                 opts |= DISP_FULLTIME;
 542                                 break;
 543 #endif
 544                         default:
 545                                 goto print_usage_message;
 546                         }
 547
 548                 argi++;
 549         }
 550
 551         /* choose a display format */
 552         if (display_fmt == FMT_AUTO)
 553                 display_fmt = isatty(fileno(stdout)) ? FMT_COLUMNS : FMT_SINGLE;
 554         if (argi < argc - 1)
 555                 opts |= DISP_DIRNAME;   /* 2 or more items? label directories */
 556 #ifdef BB_FEATURE_AUTOWIDTH
 557         /* could add a -w option and/or TIOCGWINSZ call */
 558         if (terminal_width < 1)
 559                 terminal_width = TERMINAL_WIDTH;
 560
 561         for (i = argi; i < argc; i++) {
 562                 int len = strlen(argv[i]);
 563
 564                 if (toplevel_column_width < len)
 565                         toplevel_column_width = len;
 566         }
 567 #endif
 568
 569         /* process files specified, or current directory if none */
 570         i = 0;
 571         if (argi == argc)
 572                 i = list_item(".");
 573         while (argi < argc)
 574                 i |= list_item(argv[argi++]);
 575         newline();
 576         exit(i);
 577
 578   print_usage_message:
 579         usage(ls_usage);
 580         exit(FALSE);
 581 }