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 #define DIR_RECURSE     256                     /* -R (not yet implemented) */
  92
  93 static unsigned char display_fmt = FMT_AUTO;
  94 static unsigned short opts = 0;
  95 static unsigned short column = 0;
  96
  97 #ifdef BB_FEATURE_AUTOWIDTH
  98 static unsigned short terminal_width = 0;
  99 static unsigned short column_width = 0;
 100 static unsigned short toplevel_column_width = 0;
 101 #else
 102 #define terminal_width  TERMINAL_WIDTH
 103 #define column_width    COLUMN_WIDTH
 104 #endif
 105
 106 #ifdef BB_FEATURE_LS_TIMESTAMPS
 107 static unsigned char time_fmt = TIME_MOD;
 108 #endif
 109
 110 #define wr(data,len) fwrite(data, 1, len, stdout)
 111
 112 static void writenum(long val, short minwidth)
 113 {
 114         char scratch[128];
 115
 116         char *p = scratch + sizeof(scratch);
 117         short len = 0;
 118         short neg = (val < 0);
 119
 120         if (neg)
 121                 val = -val;
 122         do
 123                 *--p = (val % 10) + '0', len++, val /= 10;
 124         while (val);
 125         if (neg)
 126                 *--p = '-', len++;
 127         while (len < minwidth)
 128                 *--p = ' ', len++;
 129         wr(p, len);
 130         column += len;
 131 }
 132
 133 static void newline(void)
 134 {
 135         if (column > 0) {
 136                 wr("\n", 1);
 137                 column = 0;
 138         }
 139 }
 140
 141 static void tab(short col)
 142 {
 143         static const char spaces[] = "                ";
 144
 145 #define nspaces ((sizeof spaces)-1)     /* null terminator! */
 146
 147         short n = col - column;
 148
 149         if (n > 0) {
 150                 column = col;
 151                 while (n > nspaces) {
 152                         wr(spaces, nspaces);
 153                         n -= nspaces;
 154                 }
 155                 /* must be 1...(sizeof spaces) left */
 156                 wr(spaces, n);
 157         }
 158 #undef nspaces
 159 }
 160
 161 #ifdef BB_FEATURE_LS_FILETYPES
 162 static char append_char(mode_t mode)
 163 {
 164         if (!(opts & DISP_FTYPE))
 165                 return '\0';
 166         if ((opts & DISP_EXEC) && S_ISREG(mode)
 167                 && (mode & (S_IXUSR | S_IXGRP | S_IXOTH))) return '*';
 168         return APPCHAR(mode);
 169 }
 170 #endif
 171
 172 /**
 173  **
 174  ** Display a file or directory as a single item
 175  ** (in either long or short format)
 176  **
 177  **/
 178
 179 static void list_single(const char *name, struct stat *info,
 180                                                 const char *fullname)
 181 {
 182         char scratch[PATH_MAX + 1];
 183         short len = strlen(name);
 184
 185 #ifdef BB_FEATURE_LS_FILETYPES
 186         char append = append_char(info->st_mode);
 187 #endif
 188
 189         if (display_fmt == FMT_LONG) {
 190                 mode_t mode = info->st_mode;
 191
 192                 newline();
 193                 wr(modeString(mode), 10);
 194                 column = 10;
 195                 writenum((long) info->st_nlink, (short) 5);
 196                 fputs(" ", stdout);
 197 #ifdef BB_FEATURE_LS_USERNAME
 198                 if (!(opts & DISP_NUMERIC)) {
 199                         memset(scratch, 0, sizeof(scratch));
 200                         my_getpwuid(scratch, info->st_uid);
 201                         if (*scratch) {
 202                                 fputs(scratch, stdout);
 203                                 if (strlen(scratch) <= 8)
 204                                         wr("          ", 9 - strlen(scratch));
 205                         } else {
 206                                 writenum((long) info->st_uid, (short) 8);
 207                                 fputs(" ", stdout);
 208                         }
 209                 } else
 210 #endif
 211                 {
 212                         writenum((long) info->st_uid, (short) 8);
 213                         fputs(" ", stdout);
 214                 }
 215 #ifdef BB_FEATURE_LS_USERNAME
 216                 if (!(opts & DISP_NUMERIC)) {
 217                         memset(scratch, 0, sizeof(scratch));
 218                         my_getgrgid(scratch, info->st_gid);
 219                         if (*scratch) {
 220                                 fputs(scratch, stdout);
 221                                 if (strlen(scratch) <= 8)
 222                                         wr("         ", 8 - strlen(scratch));
 223                         } else
 224                                 writenum((long) info->st_gid, (short) 8);
 225                 } else
 226 #endif
 227                         writenum((long) info->st_gid, (short) 8);
 228                 //tab(26);
 229                 if (S_ISBLK(mode) || S_ISCHR(mode)) {
 230                         writenum((long) MAJOR(info->st_rdev), (short) 3);
 231                         fputs(", ", stdout);
 232                         writenum((long) MINOR(info->st_rdev), (short) 3);
 233                 } else
 234                         writenum((long) info->st_size, (short) 8);
 235                 fputs(" ", stdout);
 236                 //tab(32);
 237 #ifdef BB_FEATURE_LS_TIMESTAMPS
 238                 {
 239                         time_t cal;
 240                         char *string;
 241
 242                         switch (time_fmt) {
 243                         case TIME_CHANGE:
 244                                 cal = info->st_ctime;
 245                                 break;
 246                         case TIME_ACCESS:
 247                                 cal = info->st_atime;
 248                                 break;
 249                         default:
 250                                 cal = info->st_mtime;
 251                                 break;
 252                         }
 253                         string = ctime(&cal);
 254                         if (opts & DISP_FULLTIME)
 255                                 wr(string, 24);
 256                         else {
 257                                 time_t age = time(NULL) - cal;
 258
 259                                 wr(string + 4, 7);      /* mmm_dd_ */
 260                                 if (age < 3600L * 24 * 365 / 2 && age > -15 * 60)
 261                                         /* hh:mm if less than 6 months old */
 262                                         wr(string + 11, 5);
 263                                 else
 264                                         /* _yyyy otherwise */
 265                                         wr(string + 19, 5);
 266                         }
 267                         wr(" ", 1);
 268                 }
 269 #else
 270                 fputs("--- -- ----- ", stdout);
 271 #endif
 272                 wr(name, len);
 273                 if (S_ISLNK(mode)) {
 274                         wr(" -> ", 4);
 275                         len = readlink(fullname, scratch, sizeof scratch);
 276                         if (len > 0)
 277                                 fwrite(scratch, 1, len, stdout);
 278 #ifdef BB_FEATURE_LS_FILETYPES
 279                         /* show type of destination */
 280                         if (opts & DISP_FTYPE) {
 281                                 if (!stat(fullname, info)) {
 282                                         append = append_char(info->st_mode);
 283                                         if (append)
 284                                                 fputc(append, stdout);
 285                                 }
 286                         }
 287 #endif
 288                 }
 289 #ifdef BB_FEATURE_LS_FILETYPES
 290                 else if (append)
 291                         wr(&append, 1);
 292 #endif
 293         } else {
 294                 static short nexttab = 0;
 295
 296                 /* sort out column alignment */
 297                 if (column == 0);               /* nothing to do */
 298                 else if (display_fmt == FMT_SINGLE)
 299                         newline();
 300                 else {
 301                         if (nexttab + column_width > terminal_width
 302 #ifndef BB_FEATURE_AUTOWIDTH
 303                                 || nexttab + len >= terminal_width
 304 #endif
 305                                 )
 306                                 newline();
 307                         else
 308                                 tab(nexttab);
 309                 }
 310                 /* work out where next column starts */
 311 #ifdef BB_FEATURE_AUTOWIDTH
 312                 /* we know the calculated width is big enough */
 313                 nexttab = column + column_width + COLUMN_GAP;
 314 #else
 315                 /* might cover more than one fixed-width column */
 316                 nexttab = column;
 317                 do
 318                         nexttab += column_width + COLUMN_GAP;
 319                 while (nexttab < (column + len + COLUMN_GAP));
 320 #endif
 321                 /* now write the data */
 322                 wr(name, len);
 323                 column = column + len;
 324 #ifdef BB_FEATURE_LS_FILETYPES
 325                 if (append)
 326                         wr(&append, 1), column++;
 327 #endif
 328         }
 329 }
 330
 331 /**
 332  **
 333  ** List the given file or directory, expanding a directory
 334  ** to show its contents if required
 335  **
 336  **/
 337
 338 static int list_item(const char *name)
 339 {
 340         struct stat info;
 341         DIR *dir;
 342         struct dirent *entry;
 343         char fullname[MAXNAMLEN + 1], *fnend;
 344
 345         if (lstat(name, &info))
 346                 goto listerr;
 347
 348         if (!S_ISDIR(info.st_mode) || (opts & DIR_NOLIST)) {
 349 #ifdef BB_FEATURE_AUTOWIDTH
 350                 column_width = toplevel_column_width;
 351 #endif
 352                 list_single(name, &info, name);
 353                 return 0;
 354         }
 355
 356         /* Otherwise, it's a directory we want to list the contents of */
 357
 358         if (opts & DISP_DIRNAME) {      /* identify the directory */
 359                 if (column)
 360                         wr("\n\n", 2), column = 0;
 361                 wr(name, strlen(name));
 362                 wr(":\n", 2);
 363         }
 364
 365         dir = opendir(name);
 366         if (!dir)
 367                 goto listerr;
 368 #ifdef BB_FEATURE_AUTOWIDTH
 369         column_width = 0;
 370         while ((entry = readdir(dir)) != NULL) {
 371                 short w = strlen(entry->d_name);
 372
 373                 if (column_width < w)
 374                         column_width = w;
 375         }
 376 #ifdef HAS_REWINDDIR
 377         rewinddir(dir);
 378 #else
 379         closedir(dir);
 380         dir = opendir(name);
 381         if (!dir)
 382                 goto listerr;
 383 #endif
 384 #endif
 385
 386         /* List the contents */
 387
 388         strcpy(fullname, name);         /* *** ignore '.' by itself */
 389         fnend = fullname + strlen(fullname);
 390         if (fnend[-1] != '/')
 391                 *fnend++ = '/';
 392
 393         while ((entry = readdir(dir)) != NULL) {
 394                 const char *en = entry->d_name;
 395
 396                 if (en[0] == '.') {
 397                         if (!en[1] || (en[1] == '.' && !en[2])) {       /* . or .. */
 398                                 if (!(opts & DISP_DOT))
 399                                         continue;
 400                         } else if (!(opts & DISP_HIDDEN))
 401                                 continue;
 402                 }
 403                 /* FIXME: avoid stat if not required */
 404                 strcpy(fnend, entry->d_name);
 405                 if (lstat(fullname, &info))
 406                         goto direrr;            /* (shouldn't fail) */
 407                 list_single(entry->d_name, &info, fullname);
 408         }
 409         closedir(dir);
 410
 411         if (opts & DISP_DIRNAME) {      /* separate the directory */
 412                 if (column) {
 413                         wr("\n", 1);
 414                 }
 415                 wr("\n", 1);
 416                 column = 0;
 417         }
 418
 419         return 0;
 420
 421   direrr:
 422         closedir(dir);
 423   listerr:
 424         newline();
 425         perror(name);
 426         return 1;
 427 }
 428
 429 static const char ls_usage[] = "ls [-1a"
 430 #ifdef BB_FEATURE_LS_TIMESTAMPS
 431         "c"
 432 #endif
 433         "d"
 434 #ifdef BB_FEATURE_LS_TIMESTAMPS
 435         "e"
 436 #endif
 437         "ln"
 438 #ifdef BB_FEATURE_LS_FILETYPES
 439         "p"
 440 #endif
 441 #ifdef BB_FEATURE_LS_TIMESTAMPS
 442         "u"
 443 #endif
 444         "xAC"
 445 #ifdef BB_FEATURE_LS_FILETYPES
 446         "F"
 447 #endif
 448 #ifdef FEATURE_RECURSIVE
 449         "R"
 450 #endif
 451         "] [filenames...]\n";
 452
 453 extern int ls_main(int argc, char **argv)
 454 {
 455         int argi = 1, i;
 456
 457         /* process options */
 458         while (argi < argc && argv[argi][0] == '-') {
 459                 const char *p = &argv[argi][1];
 460
 461                 if (!*p)
 462                         goto print_usage_message;       /* "-" by itself not allowed */
 463                 if (*p == '-') {
 464                         if (!p[1]) {            /* "--" forces end of options */
 465                                 argi++;
 466                                 break;
 467                         }
 468                         /* it's a long option name - we don't support them */
 469                         goto print_usage_message;
 470                 }
 471
 472                 while (*p)
 473                         switch (*p++) {
 474                         case 'l':
 475                                 display_fmt = FMT_LONG;
 476                                 break;
 477                         case '1':
 478                                 display_fmt = FMT_SINGLE;
 479                                 break;
 480                         case 'x':
 481                                 display_fmt = FMT_ROWS;
 482                                 break;
 483                         case 'C':
 484                                 display_fmt = FMT_COLUMNS;
 485                                 break;
 486 #ifdef BB_FEATURE_LS_FILETYPES
 487                         case 'p':
 488                                 opts |= DISP_FTYPE;
 489                                 break;
 490                         case 'F':
 491                                 opts |= DISP_FTYPE | DISP_EXEC;
 492                                 break;
 493 #endif
 494                         case 'A':
 495                                 opts |= DISP_HIDDEN;
 496                                 break;
 497                         case 'a':
 498                                 opts |= DISP_HIDDEN | DISP_DOT;
 499                                 break;
 500                         case 'n':
 501                                 opts |= DISP_NUMERIC;
 502                                 break;
 503                         case 'd':
 504                                 opts |= DIR_NOLIST;
 505                                 break;
 506 #ifdef FEATURE_RECURSIVE
 507                         case 'R':
 508                                 opts |= DIR_RECURSE;
 509                                 break;
 510 #endif
 511 #ifdef BB_FEATURE_LS_TIMESTAMPS
 512                         case 'u':
 513                                 time_fmt = TIME_ACCESS;
 514                                 break;
 515                         case 'c':
 516                                 time_fmt = TIME_CHANGE;
 517                                 break;
 518                         case 'e':
 519                                 opts |= DISP_FULLTIME;
 520                                 break;
 521 #endif
 522                         default:
 523                                 goto print_usage_message;
 524                         }
 525
 526                 argi++;
 527         }
 528
 529         /* choose a display format */
 530         if (display_fmt == FMT_AUTO)
 531                 display_fmt = isatty(fileno(stdout)) ? FMT_COLUMNS : FMT_SINGLE;
 532         if (argi < argc - 1)
 533                 opts |= DISP_DIRNAME;   /* 2 or more items? label directories */
 534 #ifdef BB_FEATURE_AUTOWIDTH
 535         /* could add a -w option and/or TIOCGWINSZ call */
 536         if (terminal_width < 1)
 537                 terminal_width = TERMINAL_WIDTH;
 538
 539         for (i = argi; i < argc; i++) {
 540                 int len = strlen(argv[i]);
 541
 542                 if (toplevel_column_width < len)
 543                         toplevel_column_width = len;
 544         }
 545 #endif
 546
 547         /* process files specified, or current directory if none */
 548         i = 0;
 549         if (argi == argc)
 550                 i = list_item(".");
 551         while (argi < argc)
 552                 i |= list_item(argv[argi++]);
 553         newline();
 554         exit(i);
 555
 556   print_usage_message:
 557         usage(ls_usage);
 558         exit(FALSE);
 559 }