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 #ifndef MAJOR
  94 #define MAJOR(dev) (((dev)>>8)&0xff)
  95 #define MINOR(dev) ((dev)&0xff)
  96 #endif
  97
  98 static unsigned char display_fmt = FMT_AUTO;
  99 static unsigned short opts = 0;
 100 static unsigned short column = 0;
 101
 102 #ifdef BB_FEATURE_AUTOWIDTH
 103 static unsigned short terminal_width = 0;
 104 static unsigned short column_width = 0;
 105 static unsigned short toplevel_column_width = 0;
 106 #else
 107 #define terminal_width  TERMINAL_WIDTH
 108 #define column_width    COLUMN_WIDTH
 109 #endif
 110
 111 #ifdef BB_FEATURE_LS_TIMESTAMPS
 112 static unsigned char time_fmt = TIME_MOD;
 113 #endif
 114
 115 #define wr(data,len) fwrite(data, 1, len, stdout)
 116
 117 static void writenum(long val, short minwidth)
 118 {
 119         char scratch[128];
 120
 121         char *p = scratch + sizeof(scratch);
 122         short len = 0;
 123         short neg = (val < 0);
 124
 125         if (neg)
 126                 val = -val;
 127         do
 128                 *--p = (val % 10) + '0', len++, val /= 10;
 129         while (val);
 130         if (neg)
 131                 *--p = '-', len++;
 132         while (len < minwidth)
 133                 *--p = ' ', len++;
 134         wr(p, len);
 135         column += len;
 136 }
 137
 138 static void newline(void)
 139 {
 140         if (column > 0) {
 141                 wr("\n", 1);
 142                 column = 0;
 143         }
 144 }
 145
 146 static void tab(short col)
 147 {
 148         static const char spaces[] = "                ";
 149
 150 #define nspaces ((sizeof spaces)-1)     /* null terminator! */
 151
 152         short n = col - column;
 153
 154         if (n > 0) {
 155                 column = col;
 156                 while (n > nspaces) {
 157                         wr(spaces, nspaces);
 158                         n -= nspaces;
 159                 }
 160                 /* must be 1...(sizeof spaces) left */
 161                 wr(spaces, n);
 162         }
 163 #undef nspaces
 164 }
 165
 166 #ifdef BB_FEATURE_LS_FILETYPES
 167 static char append_char(mode_t mode)
 168 {
 169         if (!(opts & DISP_FTYPE))
 170                 return '\0';
 171         if ((opts & DISP_EXEC) && S_ISREG(mode)
 172                 && (mode & (S_IXUSR | S_IXGRP | S_IXOTH))) return '*';
 173         return APPCHAR(mode);
 174 }
 175 #endif
 176
 177 /**
 178  **
 179  ** Display a file or directory as a single item
 180  ** (in either long or short format)
 181  **
 182  **/
 183
 184 static void list_single(const char *name, struct stat *info,
 185                                                 const char *fullname)
 186 {
 187         char scratch[PATH_MAX + 1];
 188         short len = strlen(name);
 189
 190 #ifdef BB_FEATURE_LS_FILETYPES
 191         char append = append_char(info->st_mode);
 192 #endif
 193
 194         if (display_fmt == FMT_LONG) {
 195                 mode_t mode = info->st_mode;
 196
 197                 newline();
 198                 wr(modeString(mode), 10);
 199                 column = 10;
 200                 writenum((long) info->st_nlink, (short) 5);
 201                 fputs(" ", stdout);
 202 #ifdef BB_FEATURE_LS_USERNAME
 203                 if (!(opts & DISP_NUMERIC)) {
 204                         memset(scratch, 0, sizeof(scratch));
 205                         my_getpwuid(scratch, info->st_uid);
 206                         if (*scratch) {
 207                                 fputs(scratch, stdout);
 208                                 if (strlen(scratch) <= 8)
 209                                         wr("          ", 9 - strlen(scratch));
 210                         } else {
 211                                 writenum((long) info->st_uid, (short) 8);
 212                                 fputs(" ", stdout);
 213                         }
 214                 } else
 215 #endif
 216                 {
 217                         writenum((long) info->st_uid, (short) 8);
 218                         fputs(" ", stdout);
 219                 }
 220 #ifdef BB_FEATURE_LS_USERNAME
 221                 if (!(opts & DISP_NUMERIC)) {
 222                         memset(scratch, 0, sizeof(scratch));
 223                         my_getgrgid(scratch, info->st_gid);
 224                         if (*scratch) {
 225                                 fputs(scratch, stdout);
 226                                 if (strlen(scratch) <= 8)
 227                                         wr("         ", 8 - strlen(scratch));
 228                         } else
 229                                 writenum((long) info->st_gid, (short) 8);
 230                 } else
 231 #endif
 232                         writenum((long) info->st_gid, (short) 8);
 233                 //tab(26);
 234                 if (S_ISBLK(mode) || S_ISCHR(mode)) {
 235                         writenum((long) MAJOR(info->st_rdev), (short) 3);
 236                         fputs(", ", stdout);
 237                         writenum((long) MINOR(info->st_rdev), (short) 3);
 238                 } else
 239                         writenum((long) info->st_size, (short) 8);
 240                 fputs(" ", stdout);
 241                 //tab(32);
 242 #ifdef BB_FEATURE_LS_TIMESTAMPS
 243                 {
 244                         time_t cal;
 245                         char *string;
 246
 247                         switch (time_fmt) {
 248                         case TIME_CHANGE:
 249                                 cal = info->st_ctime;
 250                                 break;
 251                         case TIME_ACCESS:
 252                                 cal = info->st_atime;
 253                                 break;
 254                         default:
 255                                 cal = info->st_mtime;
 256                                 break;
 257                         }
 258                         string = ctime(&cal);
 259                         if (opts & DISP_FULLTIME)
 260                                 wr(string, 24);
 261                         else {
 262                                 time_t age = time(NULL) - cal;
 263
 264                                 wr(string + 4, 7);      /* mmm_dd_ */
 265                                 if (age < 3600L * 24 * 365 / 2 && age > -15 * 60)
 266                                         /* hh:mm if less than 6 months old */
 267                                         wr(string + 11, 5);
 268                                 else
 269                                         /* _yyyy otherwise */
 270                                         wr(string + 19, 5);
 271                         }
 272                         wr(" ", 1);
 273                 }
 274 #else
 275                 fputs("--- -- ----- ", stdout);
 276 #endif
 277                 wr(name, len);
 278                 if (S_ISLNK(mode)) {
 279                         wr(" -> ", 4);
 280                         len = readlink(fullname, scratch, sizeof scratch);
 281                         if (len > 0)
 282                                 fwrite(scratch, 1, len, stdout);
 283 #ifdef BB_FEATURE_LS_FILETYPES
 284                         /* show type of destination */
 285                         if (opts & DISP_FTYPE) {
 286                                 if (!stat(fullname, info)) {
 287                                         append = append_char(info->st_mode);
 288                                         if (append)
 289                                                 fputc(append, stdout);
 290                                 }
 291                         }
 292 #endif
 293                 }
 294 #ifdef BB_FEATURE_LS_FILETYPES
 295                 else if (append)
 296                         wr(&append, 1);
 297 #endif
 298         } else {
 299                 static short nexttab = 0;
 300
 301                 /* sort out column alignment */
 302                 if (column == 0);               /* nothing to do */
 303                 else if (display_fmt == FMT_SINGLE)
 304                         newline();
 305                 else {
 306                         if (nexttab + column_width > terminal_width
 307 #ifndef BB_FEATURE_AUTOWIDTH
 308                                 || nexttab + len >= terminal_width
 309 #endif
 310                                 )
 311                                 newline();
 312                         else
 313                                 tab(nexttab);
 314                 }
 315                 /* work out where next column starts */
 316 #ifdef BB_FEATURE_AUTOWIDTH
 317                 /* we know the calculated width is big enough */
 318                 nexttab = column + column_width + COLUMN_GAP;
 319 #else
 320                 /* might cover more than one fixed-width column */
 321                 nexttab = column;
 322                 do
 323                         nexttab += column_width + COLUMN_GAP;
 324                 while (nexttab < (column + len + COLUMN_GAP));
 325 #endif
 326                 /* now write the data */
 327                 wr(name, len);
 328                 column = column + len;
 329 #ifdef BB_FEATURE_LS_FILETYPES
 330                 if (append)
 331                         wr(&append, 1), column++;
 332 #endif
 333         }
 334 }
 335
 336 /**
 337  **
 338  ** List the given file or directory, expanding a directory
 339  ** to show its contents if required
 340  **
 341  **/
 342
 343 static int list_item(const char *name)
 344 {
 345         struct stat info;
 346         DIR *dir;
 347         struct dirent *entry;
 348         char fullname[MAXNAMLEN + 1], *fnend;
 349
 350         if (lstat(name, &info))
 351                 goto listerr;
 352
 353         if (!S_ISDIR(info.st_mode) || (opts & DIR_NOLIST)) {
 354 #ifdef BB_FEATURE_AUTOWIDTH
 355                 column_width = toplevel_column_width;
 356 #endif
 357                 list_single(name, &info, name);
 358                 return 0;
 359         }
 360
 361         /* Otherwise, it's a directory we want to list the contents of */
 362
 363         if (opts & DISP_DIRNAME) {      /* identify the directory */
 364                 if (column)
 365                         wr("\n\n", 2), column = 0;
 366                 wr(name, strlen(name));
 367                 wr(":\n", 2);
 368         }
 369
 370         dir = opendir(name);
 371         if (!dir)
 372                 goto listerr;
 373 #ifdef BB_FEATURE_AUTOWIDTH
 374         column_width = 0;
 375         while ((entry = readdir(dir)) != NULL) {
 376                 short w = strlen(entry->d_name);
 377
 378                 if (column_width < w)
 379                         column_width = w;
 380         }
 381 #ifdef HAS_REWINDDIR
 382         rewinddir(dir);
 383 #else
 384         closedir(dir);
 385         dir = opendir(name);
 386         if (!dir)
 387                 goto listerr;
 388 #endif
 389 #endif
 390
 391         /* List the contents */
 392
 393         strcpy(fullname, name);         /* *** ignore '.' by itself */
 394         fnend = fullname + strlen(fullname);
 395         if (fnend[-1] != '/')
 396                 *fnend++ = '/';
 397
 398         while ((entry = readdir(dir)) != NULL) {
 399                 const char *en = entry->d_name;
 400
 401                 if (en[0] == '.') {
 402                         if (!en[1] || (en[1] == '.' && !en[2])) {       /* . or .. */
 403                                 if (!(opts & DISP_DOT))
 404                                         continue;
 405                         } else if (!(opts & DISP_HIDDEN))
 406                                 continue;
 407                 }
 408                 /* FIXME: avoid stat if not required */
 409                 strcpy(fnend, entry->d_name);
 410                 if (lstat(fullname, &info))
 411                         goto direrr;            /* (shouldn't fail) */
 412                 list_single(entry->d_name, &info, fullname);
 413         }
 414         closedir(dir);
 415
 416         if (opts & DISP_DIRNAME) {      /* separate the directory */
 417                 if (column) {
 418                         wr("\n", 1);
 419                 }
 420                 wr("\n", 1);
 421                 column = 0;
 422         }
 423
 424         return 0;
 425
 426   direrr:
 427         closedir(dir);
 428   listerr:
 429         newline();
 430         perror(name);
 431         return 1;
 432 }
 433
 434 static const char ls_usage[] = "ls [-1a"
 435 #ifdef BB_FEATURE_LS_TIMESTAMPS
 436         "c"
 437 #endif
 438         "d"
 439 #ifdef BB_FEATURE_LS_TIMESTAMPS
 440         "e"
 441 #endif
 442         "ln"
 443 #ifdef BB_FEATURE_LS_FILETYPES
 444         "p"
 445 #endif
 446 #ifdef BB_FEATURE_LS_TIMESTAMPS
 447         "u"
 448 #endif
 449         "xAC"
 450 #ifdef BB_FEATURE_LS_FILETYPES
 451         "F"
 452 #endif
 453 #ifdef FEATURE_RECURSIVE
 454         "R"
 455 #endif
 456         "] [filenames...]\n";
 457
 458 extern int ls_main(int argc, char **argv)
 459 {
 460         int argi = 1, i;
 461
 462         /* process options */
 463         while (argi < argc && argv[argi][0] == '-') {
 464                 const char *p = &argv[argi][1];
 465
 466                 if (!*p)
 467                         goto print_usage_message;       /* "-" by itself not allowed */
 468                 if (*p == '-') {
 469                         if (!p[1]) {            /* "--" forces end of options */
 470                                 argi++;
 471                                 break;
 472                         }
 473                         /* it's a long option name - we don't support them */
 474                         goto print_usage_message;
 475                 }
 476
 477                 while (*p)
 478                         switch (*p++) {
 479                         case 'l':
 480                                 display_fmt = FMT_LONG;
 481                                 break;
 482                         case '1':
 483                                 display_fmt = FMT_SINGLE;
 484                                 break;
 485                         case 'x':
 486                                 display_fmt = FMT_ROWS;
 487                                 break;
 488                         case 'C':
 489                                 display_fmt = FMT_COLUMNS;
 490                                 break;
 491 #ifdef BB_FEATURE_LS_FILETYPES
 492                         case 'p':
 493                                 opts |= DISP_FTYPE;
 494                                 break;
 495                         case 'F':
 496                                 opts |= DISP_FTYPE | DISP_EXEC;
 497                                 break;
 498 #endif
 499                         case 'A':
 500                                 opts |= DISP_HIDDEN;
 501                                 break;
 502                         case 'a':
 503                                 opts |= DISP_HIDDEN | DISP_DOT;
 504                                 break;
 505                         case 'n':
 506                                 opts |= DISP_NUMERIC;
 507                                 break;
 508                         case 'd':
 509                                 opts |= DIR_NOLIST;
 510                                 break;
 511 #ifdef FEATURE_RECURSIVE
 512                         case 'R':
 513                                 opts |= DIR_RECURSE;
 514                                 break;
 515 #endif
 516 #ifdef BB_FEATURE_LS_TIMESTAMPS
 517                         case 'u':
 518                                 time_fmt = TIME_ACCESS;
 519                                 break;
 520                         case 'c':
 521                                 time_fmt = TIME_CHANGE;
 522                                 break;
 523                         case 'e':
 524                                 opts |= DISP_FULLTIME;
 525                                 break;
 526 #endif
 527                         default:
 528                                 goto print_usage_message;
 529                         }
 530
 531                 argi++;
 532         }
 533
 534         /* choose a display format */
 535         if (display_fmt == FMT_AUTO)
 536                 display_fmt = isatty(fileno(stdout)) ? FMT_COLUMNS : FMT_SINGLE;
 537         if (argi < argc - 1)
 538                 opts |= DISP_DIRNAME;   /* 2 or more items? label directories */
 539 #ifdef BB_FEATURE_AUTOWIDTH
 540         /* could add a -w option and/or TIOCGWINSZ call */
 541         if (terminal_width < 1)
 542                 terminal_width = TERMINAL_WIDTH;
 543
 544         for (i = argi; i < argc; i++) {
 545                 int len = strlen(argv[i]);
 546
 547                 if (toplevel_column_width < len)
 548                         toplevel_column_width = len;
 549         }
 550 #endif
 551
 552         /* process files specified, or current directory if none */
 553         i = 0;
 554         if (argi == argc)
 555                 i = list_item(".");
 556         while (argi < argc)
 557                 i |= list_item(argv[argi++]);
 558         newline();
 559         exit(i);
 560
 561   print_usage_message:
 562         usage(ls_usage);
 563         exit(FALSE);
 564 }