misc-utils/namei.c

   1 /*
   2  * Copyright (C) 2008 Karel Zak <kzak@redhat.com>
   3  *
   4  * This file is part of util-linux.
   5  *
   6  * This file 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 file 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  * The original namei(1) was written by:
  17  *      Roger S. Southwick (May 2, 1990)
  18  *      Steve Tell (March 28, 1991)
  19  *      Arkadiusz Miśkiewicz (1999-02-22)
  20  *      Li Zefan (2007-09-10).
  21  */
  22
  23 #include <stdio.h>
  24 #include <unistd.h>
  25 #include <getopt.h>
  26 #include <string.h>
  27 #include <stdlib.h>
  28 #include <errno.h>
  29 #include <sys/types.h>
  30 #include <sys/stat.h>
  31 #include <sys/param.h>
  32 #include <pwd.h>
  33 #include <grp.h>
  34
  35 #include "c.h"
  36 #include "xalloc.h"
  37 #include "nls.h"
  38 #include "widechar.h"
  39 #include "strutils.h"
  40 #include "closestream.h"
  41 #include "idcache.h"
  42
  43 #ifndef MAXSYMLINKS
  44 #define MAXSYMLINKS 256
  45 #endif
  46
  47 #define NAMEI_NOLINKS   (1 << 1)
  48 #define NAMEI_MODES     (1 << 2)
  49 #define NAMEI_MNTS      (1 << 3)
  50 #define NAMEI_OWNERS    (1 << 4)
  51 #define NAMEI_VERTICAL  (1 << 5)
  52
  53
  54 struct namei {
  55         struct stat     st;             /* item lstat() */
  56         char            *name;          /* item name */
  57         char            *abslink;       /* absolute symlink path */
  58         int             relstart;       /* offset of relative path in 'abslink' */
  59         struct namei    *next;          /* next item */
  60         int             level;
  61         int             mountpoint;     /* is mount point */
  62         int             noent;          /* this item not existing (stores errno from stat()) */
  63 };
  64
  65 static int flags;
  66 static struct idcache *gcache;  /* groupnames */
  67 static struct idcache *ucache;  /* usernames */
  68
  69 static void
  70 free_namei(struct namei *nm)
  71 {
  72         while (nm) {
  73                 struct namei *next = nm->next;
  74                 free(nm->name);
  75                 free(nm->abslink);
  76                 free(nm);
  77                 nm = next;
  78         }
  79 }
  80
  81 static void
  82 readlink_to_namei(struct namei *nm, const char *path)
  83 {
  84         char sym[PATH_MAX];
  85         ssize_t sz;
  86         int isrel = 0;
  87
  88         sz = readlink(path, sym, sizeof(sym));
  89         if (sz < 1)
  90                 err(EXIT_FAILURE, _("failed to read symlink: %s"), path);
  91         if (*sym != '/') {
  92                 char *p = strrchr(path, '/');
  93
  94                 if (p) {
  95                         isrel = 1;
  96                         nm->relstart = p - path;
  97                         sz += nm->relstart + 1;
  98                 }
  99         }
 100         nm->abslink = xmalloc(sz + 1);
 101
 102         if (*sym != '/' && isrel) {
 103                 /* create the absolute path from the relative symlink */
 104                 memcpy(nm->abslink, path, nm->relstart);
 105                 *(nm->abslink + nm->relstart) = '/';
 106                 nm->relstart++;
 107                 memcpy(nm->abslink + nm->relstart, sym, sz - nm->relstart);
 108         } else
 109                 /* - absolute link (foo -> /path/bar)
 110                  * - or link without any subdir (foo -> bar)
 111                  */
 112                 memcpy(nm->abslink, sym, sz);
 113
 114         nm->abslink[sz] = '\0';
 115 }
 116
 117 static struct stat *
 118 dotdot_stat(const char *dirname, struct stat *st)
 119 {
 120         char *path;
 121         size_t len;
 122
 123 #define DOTDOTDIR       "/.."
 124
 125         if (!dirname)
 126                 return NULL;
 127
 128         len = strlen(dirname);
 129         path = xmalloc(len + sizeof(DOTDOTDIR));
 130
 131         memcpy(path, dirname, len);
 132         memcpy(path + len, DOTDOTDIR, sizeof(DOTDOTDIR));
 133
 134         if (stat(path, st))
 135                 err(EXIT_FAILURE, _("stat of %s failed"), path);
 136         free(path);
 137         return st;
 138 }
 139
 140 static struct namei *
 141 new_namei(struct namei *parent, const char *path, const char *fname, int lev)
 142 {
 143         struct namei *nm;
 144
 145         if (!fname)
 146                 return NULL;
 147         nm = xcalloc(1, sizeof(*nm));
 148         if (parent)
 149                 parent->next = nm;
 150
 151         nm->level = lev;
 152         nm->name = xstrdup(fname);
 153
 154         if (lstat(path, &nm->st) != 0) {
 155                 nm->noent = errno;
 156                 return nm;
 157         }
 158
 159         if (S_ISLNK(nm->st.st_mode))
 160                 readlink_to_namei(nm, path);
 161         if (flags & NAMEI_OWNERS) {
 162                 add_uid(ucache, nm->st.st_uid);
 163                 add_gid(gcache, nm->st.st_gid);
 164         }
 165
 166         if ((flags & NAMEI_MNTS) && S_ISDIR(nm->st.st_mode)) {
 167                 struct stat stbuf, *sb = NULL;
 168
 169                 if (parent && S_ISDIR(parent->st.st_mode))
 170                         sb = &parent->st;
 171                 else if (!parent || S_ISLNK(parent->st.st_mode))
 172                         sb = dotdot_stat(path, &stbuf);
 173
 174                 if (sb && (sb->st_dev != nm->st.st_dev ||   /* different device */
 175                            sb->st_ino == nm->st.st_ino))    /* root directory */
 176                         nm->mountpoint = 1;
 177         }
 178
 179         return nm;
 180 }
 181
 182 static struct namei *
 183 add_namei(struct namei *parent, const char *orgpath, int start, struct namei **last)
 184 {
 185         struct namei *nm = NULL, *first = NULL;
 186         char *fname, *end, *path;
 187         int level = 0;
 188
 189         if (!orgpath)
 190                 return NULL;
 191         if (parent) {
 192                 nm = parent;
 193                 level = parent->level + 1;
 194         }
 195         path = xstrdup(orgpath);
 196         fname = path + start;
 197
 198         /* root directory */
 199         if (*fname == '/') {
 200                 while (*fname == '/')
 201                         fname++; /* eat extra '/' */
 202                 first = nm = new_namei(nm, "/", "/", level);
 203         }
 204
 205         for (end = fname; fname && end; ) {
 206                 /* set end of filename */
 207                 if (*fname) {
 208                         end = strchr(fname, '/');
 209                         if (end)
 210                                 *end = '\0';
 211
 212                         /* create a new entry */
 213                         nm = new_namei(nm, path, fname, level);
 214                 } else
 215                         end = NULL;
 216                 if (!first)
 217                         first = nm;
 218                 /* set begin of the next filename */
 219                 if (end) {
 220                         *end++ = '/';
 221                         while (*end == '/')
 222                                 end++; /* eat extra '/' */
 223                 }
 224                 fname = end;
 225         }
 226
 227         if (last)
 228                 *last = nm;
 229
 230         free(path);
 231
 232         return first;
 233 }
 234
 235 static int
 236 follow_symlinks(struct namei *nm)
 237 {
 238         int symcount = 0;
 239
 240         for (; nm; nm = nm->next) {
 241                 struct namei *next, *last;
 242
 243                 if (nm->noent)
 244                         continue;
 245                 if (!S_ISLNK(nm->st.st_mode))
 246                         continue;
 247                 if (++symcount > MAXSYMLINKS) {
 248                         /* drop the rest of the list */
 249                         free_namei(nm->next);
 250                         nm->next = NULL;
 251                         return -1;
 252                 }
 253                 next = nm->next;
 254                 nm->next = add_namei(nm, nm->abslink, nm->relstart, &last);
 255                 if (last)
 256                         last->next = next;
 257                 else
 258                         nm->next = next;
 259         }
 260         return 0;
 261 }
 262
 263 static int
 264 print_namei(struct namei *nm, char *path)
 265 {
 266         int i;
 267
 268         if (path)
 269                 printf("f: %s\n", path);
 270
 271         for (; nm; nm = nm->next) {
 272                 char md[11];
 273
 274                 if (nm->noent) {
 275                         int blanks = 1;
 276                         if (flags & NAMEI_MODES)
 277                                 blanks += 9;
 278                         if (flags & NAMEI_OWNERS)
 279                                 blanks += ucache->width + gcache->width + 2;
 280                         if (!(flags & NAMEI_VERTICAL))
 281                                 blanks += 1;
 282                         blanks += nm->level * 2;
 283                         printf("%*s ", blanks, "");
 284                         printf("%s - %s\n", nm->name, strerror(nm->noent));
 285                         return -1;
 286                 }
 287
 288                 xstrmode(nm->st.st_mode, md);
 289
 290                 if (nm->mountpoint)
 291                         md[0] = 'D';
 292
 293                 if (!(flags & NAMEI_VERTICAL)) {
 294                         for (i = 0; i < nm->level; i++)
 295                                 fputs("  ", stdout);
 296                         fputc(' ', stdout);
 297                 }
 298
 299                 if (flags & NAMEI_MODES)
 300                         printf("%s", md);
 301                 else
 302                         printf("%c", md[0]);
 303
 304                 if (flags & NAMEI_OWNERS) {
 305                         printf(" %-*s", ucache->width,
 306                                 get_id(ucache, nm->st.st_uid)->name);
 307                         printf(" %-*s", gcache->width,
 308                                 get_id(gcache, nm->st.st_gid)->name);
 309                 }
 310
 311                 if (flags & NAMEI_VERTICAL)
 312                         for (i = 0; i < nm->level; i++)
 313                                 fputs("  ", stdout);
 314
 315                 if (S_ISLNK(nm->st.st_mode))
 316                         printf(" %s -> %s\n", nm->name,
 317                                         nm->abslink + nm->relstart);
 318                 else
 319                         printf(" %s\n", nm->name);
 320         }
 321         return 0;
 322 }
 323
 324 static void __attribute__((__noreturn__)) usage(void)
 325 {
 326         const char *p = program_invocation_short_name;
 327         FILE *out = stdout;
 328
 329         if (!*p)
 330                 p = "namei";
 331
 332         fputs(USAGE_HEADER, out);
 333         fprintf(out,
 334               _(" %s [options] <pathname>...\n"), p);
 335
 336         fputs(USAGE_SEPARATOR, out);
 337         fputs(_("Follow a pathname until a terminal point is found.\n"), out);
 338
 339         fputs(USAGE_OPTIONS, out);
 340         fputs(_(
 341                 " -x, --mountpoints   show mount point directories with a 'D'\n"
 342                 " -m, --modes         show the mode bits of each file\n"
 343                 " -o, --owners        show owner and group name of each file\n"
 344                 " -l, --long          use a long listing format (-m -o -v) \n"
 345                 " -n, --nosymlinks    don't follow symlinks\n"
 346                 " -v, --vertical      vertical align of modes and owners\n"), out);
 347         printf(USAGE_HELP_OPTIONS(21));
 348
 349         printf(USAGE_MAN_TAIL("namei(1)"));
 350         exit(EXIT_SUCCESS);
 351 }
 352
 353 static const struct option longopts[] =
 354 {
 355         { "help",        no_argument, NULL, 'h' },
 356         { "version",     no_argument, NULL, 'V' },
 357         { "mountpoints", no_argument, NULL, 'x' },
 358         { "modes",       no_argument, NULL, 'm' },
 359         { "owners",      no_argument, NULL, 'o' },
 360         { "long",        no_argument, NULL, 'l' },
 361         { "nolinks",     no_argument, NULL, 'n' },
 362         { "vertical",    no_argument, NULL, 'v' },
 363         { NULL, 0, NULL, 0 },
 364 };
 365
 366 int
 367 main(int argc, char **argv)
 368 {
 369         int c;
 370         int rc = EXIT_SUCCESS;
 371
 372         setlocale(LC_ALL, "");
 373         bindtextdomain(PACKAGE, LOCALEDIR);
 374         textdomain(PACKAGE);
 375         close_stdout_atexit();
 376
 377         while ((c = getopt_long(argc, argv, "hVlmnovx", longopts, NULL)) != -1) {
 378                 switch(c) {
 379                 case 'l':
 380                         flags |= (NAMEI_OWNERS | NAMEI_MODES | NAMEI_VERTICAL);
 381                         break;
 382                 case 'm':
 383                         flags |= NAMEI_MODES;
 384                         break;
 385                 case 'n':
 386                         flags |= NAMEI_NOLINKS;
 387                         break;
 388                 case 'o':
 389                         flags |= NAMEI_OWNERS;
 390                         break;
 391                 case 'x':
 392                         flags |= NAMEI_MNTS;
 393                         break;
 394                 case 'v':
 395                         flags |= NAMEI_VERTICAL;
 396                         break;
 397
 398                 case 'h':
 399                         usage();
 400                 case 'V':
 401                         print_version(EXIT_SUCCESS);
 402                 default:
 403                         errtryhelp(EXIT_FAILURE);
 404                 }
 405         }
 406
 407         if (optind == argc) {
 408                 warnx(_("pathname argument is missing"));
 409                 errtryhelp(EXIT_FAILURE);
 410         }
 411
 412         ucache = new_idcache();
 413         if (!ucache)
 414                 err(EXIT_FAILURE, _("failed to allocate UID cache"));
 415         gcache = new_idcache();
 416         if (!gcache)
 417                 err(EXIT_FAILURE, _("failed to allocate GID cache"));
 418
 419         for(; optind < argc; optind++) {
 420                 char *path = argv[optind];
 421                 struct namei *nm = NULL;
 422                 struct stat st;
 423
 424                 if (stat(path, &st) != 0)
 425                         rc = EXIT_FAILURE;
 426
 427                 nm = add_namei(NULL, path, 0, NULL);
 428                 if (nm) {
 429                         int sml = 0;
 430                         if (!(flags & NAMEI_NOLINKS))
 431                                 sml = follow_symlinks(nm);
 432                         if (print_namei(nm, path)) {
 433                                 rc = EXIT_FAILURE;
 434                                 continue;
 435                         }
 436                         free_namei(nm);
 437                         if (sml == -1) {
 438                                 rc = EXIT_FAILURE;
 439                                 warnx(_("%s: exceeded limit of symlinks"), path);
 440                                 continue;
 441                         }
 442                 }
 443         }
 444
 445         free_idcache(ucache);
 446         free_idcache(gcache);
 447
 448         return rc;
 449 }
 450